Hand truck World

A set of add-on front castors or casters, configured for attachment to a conventional three wheeled jogging stroller. The add-on front castors includes a casters system with a first casters system end, a second casters system end and a mid-casters system. A first castor mounts proximate the first casters system end and a second castor mounts proximate the second casters system end The add-on front castors also includes a fork clamp that mounts proximate the mid-casters system. The fork clamp is attachable to a front wheel fork of the jogging stroller. The front wheel fork is configured to accept a hubbed axle of the single forward wheel that is detachable to so that the front wheel fork can receive the fork clamp of the add-on front castors. The fork clamp of the front castors is attached to the front fork by first inserting the front fork between a top clamp plate a bottom clamp plate. A clamp screw threads between the top clamp plate and the bottom clamp plate, and a clamp knob is mounted to an end of the clamp screw. By turning the clamp screw, the front fork is compressed between the top clamp plate and the bottom clamp plate to securely mount the fork clamp to the front fork. The add-on castor allows a jogging stroller to function much as a conventional “baby stroller,” with swiveling castors for quick changes in the direction of forward or rearward travel.

1. An add-on front caster set for a jogging stroller, the front castors comprising:

a casters system having a first casters system end, a second casters system end and a mid-casters system;

a first castor mounted proximate the first casters system end;

a second castor mounted proximate the second casters system end;

a fork clamp mounted proximate the mid-casters system,

the fork clamp attachable to a front wheel fork of the jogging stroller;

the front wheel fork conventionally configured to accept a hubbed axle of a single forward wheel, and

the jogging stroller is a three wheeled stroller having a single forward wheel and a pair of rearward wheels, the single forward wheel detachable from the front wheel fork;

the front wheel fork having a first fork end and a second fork end; and

the fork clamp attaches to the front wheel fork proximate the first fork end and the second fork end.

2. An add-on front castors for a jogging stroller, the front castors comprising:

a casters system having a first casters system end, a second casters system end and a mid-casters system;

a first castor mounted proximate the first casters system end;

second castor mounted proximate the second casters system end;

a fork clamp mounted proximate the mid-casters system,

the fork clamp attachable to a front wheel fork of the jogging stroller;

a fork end receiver mounted proximate the mid-casters system for receiving the wheel front fork of the jogging stroller;

the front wheel fork of the jogging stroller including a first fork end and a second fork end;

the fork end receiver of the add-on front castors includes a first fork end receiver and a second fork end receiver; and

the first fork end receivable into the first fork end receiver, and the second fork end receivable into the second fork end receiver.

3. The add-on front castors of claim 2, wherein:

the fork end receiver has a top clamp plate, and the top clamp plate includes said first fork end receiver and said second fork end receiver.

4. A method for adding a front casters to a three wheeled jogging stroller, the three wheeled jogging stroller having a front wheel and a pair of rear wheels, the method comprising the steps of:

a) removing the front wheel from a front wheel fork of said jogging stroller; and

b) attaching a fork clamp of said front castors to the front wheel fork, the fork clamp mounted on a casters system, the casters system having a first casters system end, a second casters system end and a mid-casters system, a first castor mounted proximate the first casters system end, a second caster mounted proximate the second casters system end, and the fork clamp mounted proximate the mid-casters system.

5. The method of claim 4, wherein the step of attaching the fork clamp to the front wheel fork additionally includes the steps of:

c) inserting the front wheel fork between a top clamp plate a bottom clamp plate;

d) tightening a clamp screw by turning a clamp knob, the clamp screw threaded between the top clamp plate and the bottom clamp plate, and the clamp knob mounted to an end of the clamp screw; and

e) compressing the front wheel fork between the top clamp plate and the bottom clamp plate to securely mount the fork clamp to the front wheel fork.

6. The method of claim 4, additionally including the step of:

c) inserting the front wheel fork of the jogging stroller into a fork end receiver.

7. The method of claim 4, additionally including the step of:

c) inserting the front wheel fork of said jogging stroller into a fork end receiver, the front wheel fork having a first fork end and a second fork end, the fork receiver positioned proximate the mid-casters system of said front castors, and the fork end receiver of said add-on front castors including a first fork end receiver and a second fork end receiver; and the first fork end receivable into the first fork end receiver, and the second fork end receivable into the second fork end receiver.

8. An improvement for a conventional jogging stroller, the conventional jogging stroller including a frame having a front fork, the front fork including a first fork end and a second fork end, a single detachable forward wheel attached to the front fork, and a pair of rearward wheels attached to the frame, wherein said improvement comprises:

an add-on front castors, the add-on front castors including a casters system having a first casters system end, a second casters system end and a mid-casters system;

a first castor mounted proximate the first casters system end;

a second castor mounted proximate the second casters system end;

a fork clamp mounted proximate the mid-casters system,

the fork clamp attachable to the front fork of the jogging stroller; and

a first fork end receiver mounted proximate the mid-casters system of said add-on front castor, and a second fork end receiver mounted proximate the mid-casters system of said add-on front castor, the first fork end receivable into the first fork end receiver, and the second fork end receivable into the second fork end receiver.

9. An improvement for a conventional jogging stroller, the conventional jogging stroller including a frame having a front fork, a single detachable forward wheel attached to the front fork, and a pair of rearward wheels attached to the frame, wherein said improvement comprises:

an add-on front castors, the add-on front castors including a casters system having a first casters system end, a second casters system end and a mid-casters system;

a first castor mounted proximate the first casters system end;

a second castor mounted proximate the second casters system end;

a fork clamp mounted proximate the mid-casters system,

the fork clamp attachable to the front fork of the jogging stroller;

a fork end receiver mounted proximate the mid-casters system for receiving the front fork of the jogging stroller; and

the fork end receiver includes a top clamp plate

The invention provides a front wheel attachment for a three wheeled stroller, and more specifically a method and apparatus for an add-on set of wheel castors or casters, for a jogging stroller.

Based upon a simple tricycle, the jogging stroller has become a “must have” for the convenient transportation of small children. The conventional jogging stroller is based upon a triangular or alternatively a “T” shaped frame. The frame has a front fork near the forward point of the frame. A single forward wheel attaches to the front fork, and a pair of rearward wheels attach to the rear of the frame.

The three wheels of the jogging stroller form a stable tripod. Therefore, three wheeled strollers have a significant advantage over their four wheeled, baby stroller and baby carriage predecessors in that a three wheeled configuration is better suited to steer, negotiate bumps and more comfortably carry a passenger. The term “jogging stroller” typically pertains to a subtle variation of a three wheeled push-stroller; suggesting that the person pushing the stroller can safely jog or run while pushing the stroller over varying terrain. The jogging type of three wheeled stroller may include oversized wheels and a hand brake, to better facilitate running and stopping with the stroller.

Many users of jogging strollers seek a stroller that can do more than a single function or be used for more than a single utility or purpose. A multifunctional stroller can provide the economy and convenience of a single stroller while performing various tasks or duties that typically would require additional strollers, each designed for a single, specific purpose.

Jogging type strollers are made for use on relatively straight and wide sidewalks, paths and streets. With their large diameter wheels, maneuvering the jogging stroller in close or confined areas can be difficult. The user must tip the stroller to lift the front wheel of the jogging stroller up and rearward. The user can then pivot the stroller about the rear pair of wheels, while keeping the front tire off the ground. In typically congested areas, such as stores, malls and office buildings, this tipping and pivoting is very awkward and cumbersome, and so results in a significant problem. Therefore, a jogging stroller is needed that solves the problem of limited “close-quarters” maneuvering.

SUMMARY

The invention provides a method and apparatus for an add-on front castors uniquely configured for attachment to a jogging stroller of conventional design. The conventional jogging stroller is typified as having a frame with a front wheel fork, which can be simply referred to as a front fork. A single forward wheel attaches to the front fork, and a pair of rearward wheels attach to the rear of the frame.

The add-on front castors of the present invention includes a casters system as a primary component. The casters system has a first casters system end, a second casters system end and a mid-casters system. The mid-casters system is the portion of the casters system between the first casters system end and the second casters system end. A first castor mounts proximate the first casters system end and a second castor mounts proximate the second casters system end.

The add-on front castors also includes a fork clamp that mounts proximate the mid-casters system. The fork clamp is attachable to a front wheel fork of the jogging stroller. The front wheel fork is conventionally configured to accept a hubbed axle of the single forward wheel. The single forward wheel is detachable, allowing the front wheel fork to receive the fork clamp of the add-on front castors.

In a preferred alternative of the present invention, a fork end receiver is mounted proximate the mid-casters system. The fork end receiver can receive the front fork of the jogging stroller. The front fork of the conventional jogging stroller includes a first fork end and a second fork end. In a preferred embodiment of the present invention, the fork end receiver of the add-on front castors includes a first fork end receiver and a second fork end receiver. The first fork end is received into the first fork end receiver, and the second fork end is received into the second fork end receiver.

The first castor and the second castor are wheeled assemblies that each include a minimum of a single wheel. Preferably, the first castor includes a first swivel and the second castor includes a second swivel. The swivels allow the castors to respond instantly to directional changes in the motion of the jogging stroller.

The method of the present invention adds the front castors to a three wheeled jogging stroller. First, the front wheel is removed from the front fork of the jogging stroller. The fork clamp of the front castors is then attached to the front fork. Additionally, the method of the present invention can include attaching the fork clamp to the front fork by first inserting the front fork between a top clamp plate and a bottom clamp plate. Then a clamp screw is tightened by turning a clamp knob on the fork clamp. The clamp screw threads between the top clamp plate and the bottom clamp plate, and the clamp knob is mounted to an end of the clamp screw. By turning the clamp screw, the front fork is compressed between the top clamp plate and the bottom clamp plate to securely mount the fork clamp to the front fork.

To better seat the front fork into the add-on front castors, the method of the present invention can include inserting the front fork of the jogging stroller into a fork end receiver. The front fork includes a first fork end and a second fork end, and the fork end receiver is positioned proximate the mid-casters system of the front castors. The fork end receiver includes a first fork end receiver and a second fork end receiver. The first fork end is received into the first fork end receiver, and the second fork end is received into the second fork end receiver.

According to one aspect of the invention, the add-on castors gives the user the ability to quickly and easily modify the jogging stroller for tight cornering in cramped areas without tilting the stroller back to pivot about the rear wheels for turning. Specifically, the stroller configuration of the present invention includes an add-on castors that allows a jogging stroller to function much as a conventional “baby stroller,” with swiveling castors for quick changes in the direction of forward or rearward travel.

The castors comprise a support surface which is mounted upon at least two casters, one of the casters being steerable and having a castor like structure and in which steering can take place by tilting of the castoring axis of the castor like structure.

1. The castors comprising a support surface, a plurality of casters on which said support surface is mounted, a castor like structure including a castoring axis and a castorelement freely pivotable about said castoring axis for at least one of said casters, steering pivot means for enabling tilting of said castoring axis relative to said support surface and steering means operable for tilting said castoring axis of saidcastor like structure about said steering pivot means to steer the vehicle.

2. The castors as comprising three said casters.

3. The castors and comprising two fixed casters at one end and said castor like structure at the other end.

4. The castors wherein said support surface comprises a platform mounted on a frame, with said casters support directly to said frame.

5. The castors wherein said casters comprise pneumatic wheels.

6. The castors as comprising stop means for limiting the tilting of said castoring axis.

7. The castors comprising a framework, two pneumatic wheels supporting a rear of said framework, a steerable castored wheel supporting a front of said framework and including a castoring axis and a castor wheel freely pivotable about said castoring axis, aseat member mounted towards the rear of said framework, a foot support crossbar mounted towards the front of said framework, steering pivot means for enabling tilting of said castoring axis relative to said seat member and steering means operable by aperson seated in said seat for tilting said castoring axis of said steerable castor wheel about said steering pivot means to thereby steer the vehicle.

8. The castors as said framework comprises a generally “T” shaped structure comprising a cross bar and a stem with said rear pneumatic wheels located at the end of said crossbar and said castor wheel fixedly attached to the baseof said stem, and said steering pivot means is arranged to enable at least said base part of said stem to be pivotable about its own axis to incline said castoring axis of said castor wheel.

9. The castors wherein said steering means comprises a joystick extending upwardly from and mounted on said pivotable part of said stem for controlling the movement of said pivotable part of said stem to steer the vehicle.

10. The castors wherein said crossbar is mounted on said pivotable part of said stem for movement therewith.

11. The castors as comprising a hand-operated brake acting on said rear pneumatic wheels.

12. The castors as comprising stop means for limiting tilting of said castoring axis.

13. The castors comprising an “L” shaped framework including a base part for carrying luggage or other articles and an upright rear part, two fixed pneumatic wheels supporting the rear of said base part where it is connected said upright part, a castoredwheel supporting the front of said base part and including a castoring axis and a castor wheel freely pivotable about said castoring axis, steering pivot means for enabling tilting of said castoring axis relative to said base part and steering meansoperable for tilting said castoring axis of said castored wheel about said steering pivot means to steer the vehicle.

14. The castors wherein said steering pivot means comprises a horizontally rearwardly extending rod pivotable about its own axis for carrying said castored wheel, and said steering means comprises a handle connected to saidrod for pivotal movement therewith and extending upwardly to the region of the top of said upright rear part.

15. The castors as said steering pivot means comprises a horizontal pivot at the front of the base part for carrying said castored wheel and said steering means comprises a handle extending said castoring axis of saidcastored wheel upwards.

16. The castors as comprising stop means for limiting the tilting of said castoring axis.

17. The castors comprising a substantially “U” shaped frame including two horizontally extending parts spaced apart vertically and joined by a part extending between them, a pair of fixed pneumatic wheels carrying one end of the lower of the said twohorizontally extending parts, a castored wheel carrying the other end of said lower horizontally extending part and including a castoring axis and a castor wheel freely pivotable about said castoring axis, steering pivot means for enabling tilting ofsaid castoring axis relative to said frame and steering means operable for tilting said castoring axis of said castored wheel about said steering pivot means to steer the vehicle.

18. The castors wherein said steering pivot

means comprises a pivot with a horizontal axis on which said castored wheel is mounted and said steering means comprises a handle for extending said castoring axis.

19. The castors as comprising stop means for limiting the tilting of said castoring axis.

This invention relates to the castors and in particular to a steerable vehicle.

SUMMARY

It is an object of the invention to seek to provide a steerable vehicle having a novel form of steering arrangement.

According to the first aspect of the invention, the castors comprises a support surface mounted upon at least two casters wherein at least one of the casters is steerable and has a castor like structure in which steering takes place by tilting ofthe castoring axis of the castor like structure.

According to a second aspect of the invention, the castors comprises a framework supported by two pneumatic wheels at the rear and a steerable castored wheel at the front, a seat member mounted towards the rear of the framework, a foot support cross barmounted towards the front of the framework and steering means operable by a person seated in the seat for tilting the castoring axis of the steerable castored wheel.

According to a third aspect of the invention the castors comprises an “L” shaped framework having a base part for carrying luggage or other articles and an upright rear part, wherein two fixed pneumatic wheels support the rear of the base part where it isconnected to the upright part, a castored wheel supports the front of the base part and means are provided for tilting the castoring axis of the castored wheel to enable the vehicle to be steered.

According to a fourth aspect of the invention, the castors comprises a substantially “U” shaped frame comprising two horizontally extending parts spaced apart vertically and joined by a part extending between them, wherein one end of the lower ofthe two horizontally extending parts is carried by a pair of fixed pneumatic wheels, the other end of said lower horizontally extending part is carried by a castored wheel and steering means are provided for tilting the castoring axis of the castored wheel toenable the vehicle to be steered.

Single or twin pneumatic wheels castors have a body journalling the pneumatic wheels about a horizontal axis, with the body capable of swivelling on a mounting member about a vertical axis spaced from the pneumatic wheels axis. An operating member is movable axially but non-rotatably by a cam along the vertical axis between a lower position in which the body is held to the operating member and thus to the mounting member in a predetermined angular orientation, the whole being free to turn, an intermediate position in which the pneumatic wheels are free to turn and the body is free to swivel and an upper position in which a pneumatic wheels braking force is applied frictionally or mechanically by a casters lever (44, 105), the engagement of the operating member with the casters lever also holding the body in its angular position when the casters was applied.

1. The castors comprising:

a body, pneumatic wheels means rotatably mounting said pneumatic wheels means on said body,

an elongate hollow mounting member,

means mounting said body on said mounting member for rotation about a substantially vertical axis spaced from said pneumatic wheels rotatable means, and

casters means for braking said pneumatic wheels means against rotation, said casters means comprising:

a casters member slidably guided in said hollow mounting member for movement downwardly along said substantially vertical axis to release said braking, and

casters member operating means carried by said mounting member and selectively operable to act on said casters member at the region of the upper end thereof to effect said movements of said casters member.

2. The castors wherein said casters member operating means comprises a camming mechanism.

3. The castor wherein said casters member operating means comprises a cable mechanism, said mechanism including a cable of which at least the lower portion extends substantially along said substantially vertical axis.

4. The castor wherein said casters means further comprises a braking lever, and means pivotably mounting said braking lever on said body, said braking lever being movable by said casters member into braking engagement with said pneumatic wheelsmeans.

5. The castor further comprising biassing means biassing said casters member against upward movement, and wherein said casters member operating means comprises a cam, means mounting said cam on said mounting member for rotation about asubstantially horizontal axis, and a cam follower carried by said casters member at the upper end thereof, said cam follower being engaged with said cam.

6. The castor wherein said mounting member has an upper end portion carrying said cam mechanism and constructed as a housing comprising demountable wall portions.

7. The castor further comprising a spring biassing said casters member to move downwardly, and wherein said casters member operating means comprises a cable movable lengthwise within a sheath, said cable being connected to said castersmember at the upper end thereof, and said sheath being connected to said mounting member.

8. The castor further comprising screw threaded means between upper and lower portions of said casters member for selective adjustment of the length thereof.

9. The castor wherein said braking lever is mounted on said body by screw-threaded adjustment means and wherein biassing means biasses said braking lever against said braking engagement.

10. The castor further comprising casters pad wherein said pneumatic wheels means comprises a single pneumatic wheels and said braking lever is pivotably mounted on said body between first and second ends of said braking lever, said first end beingengageable by said operating member and said second end carrying said casters pad for frictionally engaging said pneumatic wheels.

11. The castors comprising:

a body,

two pneumatic wheels mounted on opposed sides of said body for rotation about a common axis, said pneumatic wheels have sleeve portions between said common axis and the outer peripheries thereof,

means rotatably mounting said pneumatic wheels means on said body,

an elongate hollow mounting member,

means mounting said body on said mounting member for rotation about a substantially vertical axis spaced from said pneumatic wheels axis, and

casters means for braking said pneumatic wheels against rotation, and casters means comprising:

an operating member slidably guided in said hollow mounting member for movement along said substantially vertical axis and being movable upwardly to exert a braking effect on said pneumatic wheels, and

a braking lever movable by said operating member to brakingly engage the exteriors of said pneumatic wheels sleeve portions.

12. The castors wherein said sleeve portions and said braking lever have thereon teeth interengageable to effect said braking.

13. The castors comprising:

a body,

pneumatic wheels means,

means rotatably mounting said pneumatic wheels means on said body,

an elongate hollow mounting member,

means mounting said body on said mounting member for rotation about a substantially vertical axis spaced from said pneumatic wheels axis, and

casters means for braking said pneumatic wheels means against rotation, said casters means comprising:

an operating member slidably guided in said hollow mounting member for movement along said substantially vertical axis and being movable upwardly to exert a braking effect on said pneumatic wheels means,

a braking lever movable by said operating member into braking engagement with said pneumatic wheels means,

screw-threaded adjustment means mounting said braking lever on said body, and

biassing means biassing said braking lever against said braking engagement.

14. The castors comprising:

a body,

pneumatic wheels means,

means rotatably mounting said pneumatic wheels means on said body,

an elongate hollow mounting member,

means mounting said body on said mounting member for rotation about a substantially vertical axis spaced from said pneumatic wheels axis, and

casters means for braking said pneumatic wheels means against rotation, said casters means comprising:

an operating member slidably guided in said hollow mounting member for movement along said substantially vertical axis and being movable upwardly to exert a braking effect on said pneumatic wheels means,

a braking lever movable by said operating member with braking engagement with said pneumatic wheels means,

means restraining said operating member against rotation relative to said mounting member, and

formations on said operating member and on said braking lever, said formations being co-operably engageable on said upward movement of the operating member to thereby prevent the rotation of said body about said substantially vertical axis.

15. The castors comprising:

a body,

pneumatic wheels means,

means rotatably mounting said pneumatic wheels means on said body,

a mounting member,

means mounting said body on said mounting member for rotation about a substantially vertical axis spaced from said pneumatic wheels axis,

casters means for braking said pneumatic wheels means against rotation, said casters means comprising an operating member movable upwardly to exert a braking effect on said pneumatic wheels means, and

formations on said operating member and on said body, said formations being co-operably engageable on downward movement of said operating member to thereby hold said body in a predetermined angular relationship to said mounting member.

16. The castors comprising:

a body,

two pneumatic wheels,

means mounting said pneumatic wheels on said body for rotation about a substantially horizontal axis, each of said pneumatic wheels having an outer rim and means defining an external cylinderical surface concentric with said substantially horizontal axis and locatedradially inwardly of said outer rim,

castor mounting means,

means mounting said body on said castor mounting means for swivelling about a substantially vertical axis spaced from said horizontal pneumatic wheels axis,

a casters arm, said casters arm having two portions each adapted for braking engagement with a respective one of said cylindrical surfaces,

means mounting said casters arm on said body for pivotation between positions respectively of disengagement from said pneumatic wheels and of braking engagement therewith,

an elongate operating member, said casters arm portions being located on said casters arm between said operating member and said casters arm mounting means,

means guiding said elongate operating member on said castor mounting means for movement along said substantially vertical axis from a non-braking position to a position in which said operating member acts on said casters arm to cause said brakingengagement of said casters arm, said operating member movement being in the upward direction.

17. The castors comprising:

a body,

pneumatic wheels means,

means mounting said pneumatic wheels means on said body for rotation about a substantially horizontal axis,

castor mounting means,

means mounting said body on said castor mounting means for swivelling about a substantially vertical axis spaced from said horizontal pneumatic wheels axis,

a casters arm,

means mounting said casters arm to said body for pivotation between positions respectively for disengagement from said pneumatic wheels and of braking engagement therewith,

an elongate operating member,

means guiding said elongate operating member on said castor mounting means for movement along said substantially vertical axis from a non-braking position to a position in which said operating member acts on said casters arm to cause said brakingengagement of said casters arm, said operating member movement being in the upward direction,

means restraining said operating member and said mounting means against relative rotation about said substantially vertical axis,

an upwardly facing surface on said operating member with a series of teeth extending radially of said vertical axis formed on said upwardly facing surface, and

a tooth formed on an end portion of said casters arm, said tooth being engageable with said casters arm, thereby preventing said swivelling of said body on said mounting means.

18. The castors comprising:

a body,

pneumatic wheels means,

means mounting said pneumatic wheels means on said body for rotation about a substantially horizontal axis,

castor mounting means,

means mounting said body on said castor mounting means for swivelling about a substantially vertical axis spaced from said horizontal pneumatic wheels axis,

a casters arm,

means mounting said casters arm on said body for pivotation between positions respectively of disengagement from said pneumatic wheels and of braking engagement therewith,

an elongate operating member,

means guiding said elongate operating member on said castor mounting means for movement along said substantially vertical axis from a non-braking position to a position in which said operating member acts on said casters arm to cause said brakingengagement of said casters arm, said operating member movement being in the upward direction,

operating member drive means, said operating member comprises yoke means receiving a drive for said operating member from said drive means,

a casters arm actuating element aligned with said yoke means and engageable with said casters arm, and

screw-threaded means between said yoke means and said actuating element permitting adjustment of the length of said operating element effective between said drive means and said casters arm.

The invention relates to castors and more particularly to castors incorporating braking means.

There is known from United Kingdom Patent Specification GB No. 2 096 254 A The castors comprising a body mounting pneumatic wheels for rotating about a rolling axis, an attachment member for mounting the body on an article, the body and attachment memberbeing relatively movable about an upright swivelling axis spaced from the rolling axis, and a braking element movable downwardly along the swivelling axis to casters the pneumatic wheels against rotation and to hold the body against the swivelling movement. Thedownward movement of the braking element to effect braking necessarily imposes on the castor forces which tend to separate its components parts, and it moreover presents difficulty in employing the castor for remote controlled braking as by a Bowdencable connection.

It is accordingly an object of the present invention to provide The castors in which braking forces are applied in a direction tending to urge the component parts thereof together.

It is also an object of the invention to provide The castors having pneumatic wheels braking means suited to operation by way of a Bowden cable.

It is a further object of the invention to provide The castors having a braking element engageable with the pneumatic wheels thereof to apply a braking force thereto, and an operating member linked with the braking element and movable upwardly to cause thebraking force to be applied.

SUMMARY

In accordance with the invention there is provided The castors comprising a body rotatably carrying at least one pneumatic wheels, a mounting member on which the body is carried for rotation in use about a generally vertical axis spaced from the pneumatic wheels axis,and a casters mechanism for braking the pneumatic wheels against rotation, the casters mechanism including an operating member guided by the mounting structure for upward movement to exert a braking effect on the at least one pneumatic wheels.

Because of the upward direction of movement of the operating member to effect braking, the forces acting in the castor during braking tend to hold the castor parts together rather than to urge them apart as occurs when an operating member has tobe moved downwardly to apply braking pressure, as in conventional castor braking arrangements.

The operating member can be operable by means of a cam accommodated in the mounting structure, but the direction of movement of the casters operating member makes it readily possible to arrange for casters operation from locations remote from thecastor, for example, by way of a Bowden cable connection, in a much more convenient way than is permitted by the conventional constructions.

The invention can be readily embodied in single pneumatic wheels or twin pneumatic wheelsed castors in which the movement of the operating member to apply the braking force is arranged also to latch the body against swivelling about the vertical axis. Additionally,the operating member can be arranged to be movable to cause the body to be latched relative to the mounting structure in a predetermined angular orientation about the vertical axis, without pneumatic wheels braking.

Free floating castors includes a casters system assembly mounted to move relative to a vertical axis of rotation at which it is attached to a trolley to provide space for the casters system to move freely within a fixed area. At least one shaft extends perpendicular to the vertical axis of rotation and the axis of rotation of the casters system on its axle. A bearing permits movement of the axle along the shaft in between two limits. In a second embodiment, a rotary joint assembly is connected between the vertical axis of rotation and the casters system to permit the casters system to revolve through 360° around a vertical axis of the rotary joint assembly.

1. A castors apparatus for attachment to a trolley comprising:

a bearing for attachment to a trolley and having a generally vertically extending castors vertical axis;

a bracket assembly retained by said bearing and rotatable about said castors vertical axis, said bracket assembly including at least one generally horizontally extending shaft having a stop at either end thereof;

at least one casters system rotatably mounted on an axle for engaging and rolling along a surface; and

a mounting means attached to said axle and engaging said shaft for permitting free movement of said casters system and said axle in a generally horizontal plane along said shaft between both said stops transverse to said castors vertical axis within a predetermined area surrounding said castors vertical axis, said mounting means including at least one pulley attached to said axle and having a peripheral groove engaging said shaft, whereby when said bearing is attached to a trolley, said casters system and said axle trail said castors vertical axis along a path of travel of the trolley and said casters system is prevented from wedging and/or fishtailing upon reversal of a direction of the trolley along the path of travel.

2. The castors apparatus wherein said bracket assembly includes another generally horizontally extending shaft, both shafts being positioned on opposite sides of said casters system, said mounting means engaging each of said shafts for permitting the free movement of said casters system.

3. The castors apparatus including another casters system rotatably mounted on said axle for engaging and rolling along a ground surface; said shaft being positioned between both casters systems.

4. The castors apparatus wherein said mounting means includes at least one roller attached to said axle and engaging said shaft.

5. The castors apparatus wherein said shaft is an upper shaft and including a lower shaft extending generally parallel to and below said upper shaft between both stops, said mounting means engaging said upper shaft when said casters system is resting on a surface and engaging said lower shaft only when said casters system is lifted away from the surface.

6. The castors apparatus including another casters system rotatably mounted on an axle for engaging and rolling along a ground surface; another shaft extending generally parallel to said at least one shaft, generally horizontal extending both shafts being positioned between said casters systems, and a generally “T” shaped housing attached to said axle between both casters systems and both shafts, and one of a roller and a linear bushing attached to said housing and engaging both shafts to attach both casters systems to said bracket assembly.

7. The castors apparatus wherein said shaft is one of circular or square in cross section.

8. A castors apparatus for attachment to a trolley comprising:

a bearing adapted to be attached to a trolley and having a generally vertically extending castors vertical axis;

a bracket assembly retained by said bearing and rotatable about said castors vertical axis, said bracket assembly including at least one generally horizontally extending shaft;

at least one casters system assembly rotatably mounted on an axle for engaging and rolling along a ground surface;

a mounting means attached to said axle and engaging said shaft for permitting free movement of said casters system transverse to said castors vertical axis within a predetermined area surrounding said castors vertical axis whereby when said bearing is attached to a trolley, said casters system trails said castors vertical long a path of travel of the trolley and said casters system is prevented from wedging and/or fishtailing upon reversal of a direction of the trolley along the path of travel along of travel; and

another casters system rotatably mounted on an axle for engaging and rolling along a ground surface, another shaft extending generally parallel to said one shaft, both shafts being positioned between both casters systems, and a generally “T” shaped housing attached to said axle to said housing and engaging both shafts to attach both casters systems to said bracket assembly.

9. The castors apparatus wherein said bracket assembly includes another generally horizontally extending shaft, said shafts being positioned on opposite sides of said casters system, said mounting means engaging each of said shafts for permitting the free movement of said casters system.

10. The castors apparatus wherein each said mounting means includes at least one of a pulley, a roller or a pinion engaging said shaft.

11. The castors apparatus wherein said bracket assembly includes means coupling said casters system and axle to said bracket assembly.

12. A castors apparatus for attachments to a trolley comprising:

a bearing for attachment to a trolley and having a generally vertical extending castors vertical axis;

a bracket assembly retained by said bearing and rotatable about said castors vertical axis, said bracket assembly including a generally horizontally extending upper shaft having a stop at either thereof and a lower shaft extending generally parallel to and below said upper shaft;

at least one casters system rotatably mounted on an axle for engaging and rolling along a surface; and

a mounting means attached to said axle and engaging said shafts for permitting free movement of said casters system and said axle generally horizontal plane along said upper shaft between both stops transverse to said castors vertical axis within a predetermined area surrounding said castors vertical axis whereby when said bearing is attached to a trolley, said casters system and said axle trail said castors vertical axis along a path of travel of the trolley and said casters system is prevented from wedging and/or fishtailing upon reversal of a direction of the trolley along the path of travel.
Description

BACKGROUND

The present invention relates generally to castors and more particularly to free floating castors.

The state of the art castors, as we are all aware, are casters systems that trail the direction of motion of the platform or trolley onto which they are mounted. The casters system in the castors assembly has freedom to revolve, in the horizontal plane, around the vertical axis of the castors assembly, through 360°. The casters system being located at a certain distance (trail distance) from the single vertical axis of the assembly at the end of a trail arm makes the casters system follow the direction of the motion of the trolley.

Standard castors have two inherent flaws one, the castors have a tendency to get wedged, and two, swiveling/fishtailing of the trolley onto which the castors are fitted when the direction of motion is reversed.

Wedging is a momentary restriction in the smooth motion of a castors trolley experienced during reversal of direction of its travel. While reversing the direction of motion, the castors becomes dynamically unstable. The casters system initially follows the reverse path and then deviates. During this process, the castors have to revolve to realign. The castors could either revolve in the same or opposite directions. Wedging occurs when both castors revolve either inwards or outwards, i.e., in opposite directions. During the reversal motion, the casters systems get dragged momentarily until they realign. In order to overcome wedging, extra efforts needs to be applied which will be proportional to the weight on the casters systems. This difficulty would, in day-to-day life, have been experienced while handling baggage trolleys at airports, etc.

Fishtailing of the trolley also occurs while reversing. Owing to the revolving action, the castors could revolve in the direction opposite to the intended one. For instance, while reversing the direction from forward to rearward, the castors could revolve in clockwise direction. Thereby, the trolley will swing towards the right hand side. In case of an obstruction ahead and in order to avoid it, one needs to apply additional force to turn left. However, on doing so, one finds a momentary resistance to the effort because the castors are revolving in the wrong direction. By continuing to pull backwards, one could hit the obstacle. The way out would be to push forward again, make the castors revolve in the opposite direction and then pull back or apply enough force to drag the casters systems in the desired direction.

SUMMARY

The present invention concerns an apparatus for improving the operation of castors by providing space for the casters system to move freely. The casters system thus can float freely within a fixed area. The principle of implementing the free floating castors can be done in two ways. One is by providing at least one shaft perpendicular to both the castors vertical axis and the casters system axle axis and thus making the casters system axle free to along the shaft between two stoppers/limits. The second principle is that of double rotary joints wherein an additional vertical rotary axis/joint is provided equidistant between the vertical axis and the center of the casters system. The additional rotary axis/joint enables the trail arm to revolve through 360° in the horizontal plane around it. In comparison to this, the standard castors have only one vertical axis.

The entire assembly can be fabricated according to any desired specification. There is no limit either to its size or weight carrying capacity. In terms of costs, the only added cost being that of shaft or rotary joint to a certain extent additional machining and fabrication charges.

Free floating castors find its usage and can be installed on all trolleys, equipment bodies, automated guided vehicles, etc. on which the standard castors are installed and on platforms/bodies on which the phenomenon of “wedging”/”fish-tailing” hitherto precluded installation/usage of castors. The free floating castors, according to the present invention, is easier in operation, allows free and better maneuverability thereby increasing its efficiency–enabling installation of the device on a wider range of platforms–and is cost effective, when compared with the state of the art castors.

For those of you who want to gain some insight into Casters, it will do you a great deal of good to first understand the terminology related to castors. Which includes jargon or names of completed casters, parts of castors, and how do they work together. Besides this it will also help you to understand the difference between a complete caster, a wheel and a complete wheel.Casters are a combination of the caster yoke, a complete wheel; including the bearings, an axle and any other optional parts desired like, brakes, thread guards, and so on. A wheel is mere wheel unless it is attached to a caster yoke and axle. Likewise, a caster yoke is not considered a castor unless it has a wheel incorporated into it and without his it would simply be called caster yoke. 

Coming to the industry and market related to castors, both the wholesalers and the distributors stock “parts”, in the sense that all the unassembled parts that make up completed casters. The parts that are unassembled are basically stocked to provide the greatest range of potential caster combinations and at the same time limiting inventory.

It is important to note that castor yoke may be available in various combinations and permutation. One castor yoke may have anywhere between 10-20 wheel types, 1-10 bearing types and many other optional parts available in making up a completed caster. The wholesalers or distributor will add or incorporate parts depending upon individual needs and requirement of the client.

It is advised that before getting castors assembled it is important to check out the advantages, disadvantages and characteristics of what you are going to get installed and assembled.

Castors serve a full range of business, institutional, and industrial applications. If the client needs help identifying his/her requirements or needs a caster designed to fit the exact needs and specifications then such clients should contact the wholesalers or distributors and discuss everything in detail before ordering one.

Whether one is looking for innovative technology, or a more sophisticated design, along with functionality aspect should be conveyed to the seller clearly so that you don’t end up getting into a wrong or a bad deal. Since casters can be tailor made depending upon individual requirement, it is advised that the needs are identified before assembling of castors start. If you are planning to order casters online, it is important that you visit the right website, that sells what it promises and has a clearly laid out refund and return policy.

Pneumatic wheels are replacement wheels that are extremely suitable for uneven such as Agricultural, Institutional; Industrial floors that usually demand rough and tough usage. Some of their features include the shock absorbing characteristics, their quiet operation, and ease of rolling that make them ideal for rough surface. Pneumatic Wheels are suitable for manual operation for both indoor and outdoor environments.It is important to consider various factors while trying to identify proper castors and Pneumatic wheel because at the end each application is unique in its usage, function and output. IT is advised that a buyer should consider buying the castor or Pneumatic wheel that is suits their needs and application.

Criteria to consider before Selecting Castors and Pneumatic wheels include load weight, floor conditions, unusual conditions, temperature, swivel radius, Rollability and technical assistance.

The more heavy load is, larger the wheel diameter required for the castor and the Pneumatic wheel. The load weight also influences the rollability. It is advised that for loads over 250 pounds bearings be incorporated. When the momentary load imposed upon a castor or wheel when the load is dropped on equipment, strike obstruction or vibrates it should be able to absorb the shock and impact.

Casters and the Pneumatic wheels you opt for must be large enough to suit your peculiar floor conditions. It should be able to deal with cracks in the floor, moldings, or any other unforeseen obstacles.

The larger the wheel, the easier it is to roll. Make a note that a hard, narrow crowned tread rolls more easily than a flat soft tread on a smooth floor, but the wheel may be hard on the floor. Soft treads protect floors and pass over floor obstructions more easily. Make sure you use the largest wheel diameter for best results. Likewise, the larger the swivel radius, the easier the castor will rotate.

Before buying Casters and Pneumatic wheels you should identify your needs and then look for the particular features to suit your requirements. If need be you should seek technical assistance. This will help you getting the right castors and wheels.

When are castors not casters? You might think you know what someone is talking about when then say the word castors to you. Below is just some of the meanings of this interesting word. 

Castors 1
Definition: A genus of rodents, including the beaver. See Beaver.
Casters 2
Definition: Castoreum. See Castoreum.
Castors 3
Definition: A hat, esp. one made of beaver fur; a beaver.
Casters 4
Definition: A heavy quality of broadcloth for overcoats.
Castors 5
Definition: See Casters, a small wheel.
Casters 6
Definition: the northernmost of the two bright stars in the constellation Gemini, the other being Pollux.
Castors 7
Definition: Alt. of Castorite
Casters 8
Definition: type genus of the Castoridae: beavers
castors 9
Definition: a hat made of beaver fur or similar material
casters 10
Definition: a pivoting roller attached to the bottom of furniture or trucks or portable machines to make them movable
castors 11
Definition: a shaker with a perforated top for sprinkling powdered sugar
Casters 12
Definition: a multiple star with 6 components; second brightest in Gemini; close to Pollux

This invention relates to castors, for example for builders’ staging and hospital beds. The castor includes an upright spindle on which wheel-carrying plates are mounted, a wheel having an axle extending through openings in the plates, a wheel braking device, cam means for moving the axle along the openings to and from a braking position, said openings being of constant depth so that the axle has substantially no play and the cam means has cam slots so shaped that movement of the cam plates causes braking device to engage the wheel firmly when not loaded, the load being then shared by the axle and the wheel.

Hospital bed castors comprising a wheel carrying device including an upright spindle, wheel carrying plates spaced apart from each other and carried by the lower end of the spindle, a wheelhaving an axle, said axle extending horizontally through horizontally elongated openings in the plates, a wheel braking surface carried by said device between said plates, a pivot having a fixed axis extending through the axle-carrying plates and saidaxis being parallel with the axle to one side thereof, and cam plates pivoted on said pivot, said cam plates having elongated cam slots extending at a substantial angle to the elongated openings, said slots being engaged by the wheel axle and of suchshape as to move the wheel axle along the elongated openings during pivoting of said cam plates, said axle moving from a position where the wheel is spaced from the braking surface to a position where the wheel is engaged by said braking surface, saidopenings being made of constant depth so that the axle has substantially no vertical play, and the cam slots being shaped in such a manner that movement of the cam plates by the user to the brake-on position causes the braking surface and the wheel to beengaged firmly even when not loaded, the said elongated openings stopping short of passing beneath said braking surface whereby the load is shared by the axle and the surface.

Casters as claimed wherein the braking surface is provided by an abutment which is located at such a position that it contacts the wheel in the brake-on position within the arc taken about said axle and extending from 10° to 80° offset from the top of the wheel on the forward side of the castor, the cam plates having a handle which extends below the abutment.

casters as claimed wherein the braking surface is provided by a bar mounted in the plates and located between them.

casters as claimed wherein the braking surface abutment is located at such a position that it serves as a stop engaged by the handle extending from the cam plates.

This invention relates to castors for use on builders’ staging, hospital beds and other devices that require to be wheeled along at times and locked against movement at other times by braking the wheels of the castors.

casters of this kind forms the subject according to which the castor comprises a wheel carrying device including an upright spindle and wheel carrying plates spaced apart from each other andcarried by the lower end of the spindle, a wheel having an axle, said axle extending through openings in the plates, a wheel braking surface carried by said device and cam plates pivoted on the axle carrying plates for moving the wheel axle along theopenings from a position where the wheel is spaced from the braking surface to a position where the top part of the wheel is engaged by said braking surface, said openings in the plates being elongated on a horizontal line and having adjacent endslocated directly below the vertical axis of the spindle where they are enlarged vertically to give the axle a small vertical play; said cam plates having cam slots therein engaged by the axle and being pivoted on the wheel carrying plates at their endsremote from said enlarged ends of said openings at a point substantially horizontally in line with said horizontal openings.

While this castor has been very successful in practice certain difficulties are sometimes experienced. In particular it is necessary to form said openings with a fairly high degree of accuracy. Moreover, when the braking surface deforms thetyre above a certain load the axle seats on the upper surfaces of the openings and any greater load does not increase the braking force. The braking force depends on the load. Substantially no load is taken on the axle but the load is transmittedthrough the wheel to the ground. If the openings are further enlarged vertically to obtain greater braking load, a wedging action occurs which makes it difficult to release the brake.

According to the present invention the openings are made of constant depth so that the axle has substantially no vertical play and the cam slots are shaped in such a manner that movement of the cam plates by the user to the brake-on positioncauses the braking surface to engage the wheel firmly even when not loaded, the load being then shared by the axle and the wheel.

Thus the cam surfaces of the slots press the wheel directly on to the braking surface. By actual tests we have found that the braking effect is practically the same when the castor is under substantially no load as when it is loaded up to fullload e.g. 600 lbs. whereas with the castor of British Patent 882617 the braking is very effective under high load but is too small at substantially no load to be acceptable in certain conditions especially after some wear on the braking surface. Withthe present invention a greater amount of wear of the braking surface can be tolerated. Wear is also less with the present invention because no relative movement accurs between the braking surface and the wheel after they have been engaged whereas withthe castor of British Patent 882617 some such relative movement does occur e.g. when a workman is getting on and off a light weight staging fitted with the castors.

Preferably the braking surface is provided by an abutment which is provided at such a position that it contacts the wheel (i.e. in the brake-on position) within an arc extending from 10° to 80°, offset from the top of the wheel onthe forward side of the castor i.e. the side of the axle remote from the pivot of the cam plates, the cam plates having a handle which extends below the abutment.

The abutment may be formed by turning down the front part of a plate that connects the wheel carrying plates together, or by a separate bar located below that abutment. The separate bar is preferred especially if the wheel carrying plates areformed integrally by pressing a plate into an approximately U-shaped section; the bar then serving to strengthen and stiffen this plate section.
With this construction a greatly increased braking action has been achieved .

Retractable castors mechanism for attachment to an article of furniture or other heavy object including a castor shank that is rotatably received by a socket of a retaining member. A mainspring biases the retaining member and the castor downwardly, and a latch pin is engageable with the retaining member to latch the castor against the force of the spring in an inoperative retracted position. The latch is operated by a releasing lever having a foot portion that rests against the floor, so that a slight push of the article across the floor causes the latch pin to disengage the retaining member, allowing the castor to descend to an operative position.

A retractable castor mechanism for mounting on a movable article so that the article can be rolled along a floor comprising:

a housing;

a retaining member slidably received by said housing for vertical reciprocation therein and including an outer sleeve and an inner socket;

a castor having a shank inserted in said socket and movable with said retaining member between an extended operative position and a retracted inoperative position;

a spring disposed within said sleeve and biasing said caster toward said operative position;

latching means for latching said castor in said inoperative position against the force of said compression spring;

said latching means including a latch pin movable into a retaining member engaging position;

a releasing lever pivotably mounted on the outside of said housing and connected to said latch pin;

said releasing lever having a foot portion positioned with respect to said housing to frictionally engage said floor when said castor is in said inoperative position; and

latch spring means for urging said foot portion toward said floor and simultaneously urging said latch pin toward said socket engaging position, whereby said retaining member and said castor can be released by said latch pin to move said castorfrom said inoperative position to said operative position by moving said article relative to said floor.

The retractable castor mechanism of claim 1 wherein said foot portion includes a movable tip for frictionally engaging said floor and a tip spring engaging said lever and urging said tip against said floor.

A retractable castor mechanism for mounting on a movable article so that the article can be rolled along a floor comprising:

a housing;

a castor movable relative to said housing between an extended operative position and a retracted inoperative position;

said castor including a shank received within said housing for substantially vertical reciprocation;

resilient means for biasing said castor downwardly toward said operative position; and

means for releasably latching said castor in said inoperative position against the force of said resilient means, said latching means comprising a releasing lever movable between a castor latching position and a castor unlatching position and alatch spring biasing said lever toward said castor latching position, said lever having a foot portion oriented with respect to said housing to frictionally engage said floor when said lever is in said castor latching position, whereby said lever can bemoved from said castor latching position to said castor unlatching position by moving said article relative to said floor.

The retractable castor mechanism of wherein:

said latching means further comprises an opening in said housing, and a latch pin connected to said lever and extending through said opening; and

said mechanism further comprises retaining means within said housing for transmitting the force of said resilient means to said castor, said retaining means being engageable by said latch pin to latch said castor in said inoperative position.

The retractable castor mechanism of, wherein said foot portion of said releasing lever includes a movable tip for engaging said floor and means for biasing said tip against said floor when said lever is in said latched position.

The retractable castor mechanism of, further comprising a retaining member including a socket in which said castor is received, said retaining member being slidably received by said housing for vertical reciprocation therein.

The retractable castor mechanism of, wherein said latching means furhther includes a horizontally movable latch pin connected to said lever for engaging said retaining member when said lever is in said castor latching position.

A retractable castor mechanism for mounting on a movable article so that the article can be rolled along a floor comprising:

a housing;

a castors movable relative to said housing between an extended operative position and a retracted inoperative position;

sais castor including a shank received within said housing for substantially vertical reciprocation;

resilient means for biasing said castor downwardly toward said operative position; and

means for releasably latching said castor in said inoperative position against the force of said resilient means, said latching means comprising a releasing lever mounted on said housing having a foot portion positioned with respect to saidhousing to frictionally engage said floor when said castor is in said inoperative position, said latching means releasing said castor from said inoperative position in response to movement of said releasing lever, whereby said castor can be caused tomove from said inoperative position to said operative position by moving said article relative to said floor.

The retractable castor mechanism of, wherein said latching means further includes latch spring means connected to said housing, urging said foot portion against said floor.

The retractable castor mechanism, wherein said foot portion includes a movable tip and spring means for urging said tip against said floor for frictional engagement therewith when said castor is in said inoperative position.

A retractable castor mechanism for mounting on a movable article so that the article can be rolled along a floor comprising:

a housing;

a castor movable relative to said housing between an extended operative position and a retracted inoperative position;

said castor including a shank received within said housing for substantially vertical reciprocation;

means for releasably latching said castor in said inoperative position against the force of said resilient means; and

a retaining member having a socket within which said shank is rotatably received for vertical reciprocation therewith, said socket being engaged by said resilient means and urged downwardly within said housing by said resilient means.
Description
BACKGROUND

The present invention relates to castors, and more particularly to a castor mechanism that permits a castor to be moved from an operative position to an inoperative position.

Articles of furniture and other heavy objects are often provided with castors so that they can be moved more easily. The castors do not, however, provide a base for the article that is as solid as the legs or bottom surface of the articleitself. It is desirable, therefore, that the castors be made retractable to provide better support and to lower the article to its normal height when it is not being moved.

Retractable castor mechanisms that have been proposed previously are often difficult to operate. Many require that the article be lifted off the castor which is then secured in a retracted position. This arrangment is unsatisfactory because thedesired to avoid lifting the article is often the reason for providing castors in the first place. Even if the article is not heavy, it is usually difficult for one person to simultaneously lift it and operate the castor mechanism. Other difficultiesarise because a single person cannot operate more than one such mechanism at a time, while most articles require four or more castors for adequate support.

Some previously known castor mechanisms have included jacks by which the article can be raised and lowered, but such mechanisms are often unduly complex and difficult to use, especially in a confined area. Moreover, most previously known castormechanisms required that the user be able to reach the mechanism to extend or retract it, and the location of the mechanism under the article and near the floor is often not conveniently accessible.

A principal object of the present invention is to provide an improved castor mechanism that can be operated conveniently by forces applied to the article on which the castor is mounted, without direct access to the castor mechanism itself.

SUMMARY

The present invention comprises a retractable castor mechanism for attachment to items of furniture such as chairs, sofas, desks, tables and beds, and to other relatively heavy objects, such as home appliances and industrial machines. Themechanism can be latched in a retracted inoperatve position to allow the article to rest on its own legs by simply pressing downwardly on the article. It can be unlatched, so that the article is raised by a spring and rides on the castors by simplypulling the article a very short distance along the floor.

The mechanism includes a castor of conventional construction having a vertical shank that may be rotatably received by a socket in a retaining member. A mainspring engages the retaining member and biases the castor downwardly toward the bottomof a housing causing it to extend beneath the article in an operative position.

When the retaining member is moved upwardly in the housing retracting the castor into an inoperative position, a latching mechanism holds the retaining member and the castor against the force of the spring. The latching mechanism can include alatch pin that projects through the housing to engage the retaining member and a pivotable releasing lever that operates the latch pin. A latch spring biases the lever and pin toward a latching position.

The releasing lever may have a foot portion that frictionally engages the floor when the castor is retracted. In response to a slight pull of the article along the floor, the drag produced by the foot causes the lever to pivot against the forceof the latch spring, and the movement of the lever withdraws the latch pin from engagement with the retaining member. The mainspring, acting through the retaining member, then returns the castor to its operative position.

Other features and advantages of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the invention.

The castor mechanism can be included as an original part of the article, or it can readily be added to a pre-existing article. In either case, the housing is simply positioned on the inside surface of the leg or other member so thatthe castor 14 is even with the bottom of the article when retracted. Wood screws 62 are then used to secure the housing to the leg.

The mechanism 10 is small and compact, of simple construction, and is easily manufactured, but provides convenient movement of the castor 14 between its operative and inoperative positions by simply pressing down on the article or pulling thearticle a short distance along the floor.

While a particular form of the invention has been illustrated and described, it will be apparent that various modifications can be made without departing from the spirit and scope of the invention.

A support structure for a caster or castors, castors provided with such a support-structure, and a trolley with castors is described. The support structure comprises a first member , a second member  that is rotatable with respect to the first member about a pivot axis, and magnetic means that is operable up to a certain torque to restrain movement of the rotatable member from one angular position with respect to the first member. Preferably the magnetic means comprises at least one hair of magnetically co-operable components. Preferably one component of the at least one pair of components is a permanent magnet. In another angular positions without registration of the first and second members free rotation is possible unless and until re-registration occurs.

The present invention relates to a support structure for castors, to casters provided with such a support structure, and to a trolley with castors, especially a manually movable trolley, such as a supermarket trolley, a roll container, or a hospital trolley, but without limitation to same.

The majority of such trolleys, intended for the transport of goods or persons, are normally provided with four castors, each freely rotatable through 360°. In practice, this frequently leads to steering difficulties, either duringrequired straight line movement, or when negotiating a corner or bend.

With a view to providing some steering control it is known to restrain the freedom of rotation of castors by means of a spring loaded pin engaging in a recess, but such control proposals have been subject to minimal adoption.

An aim of the present invention is the provision of an improved support structure for castors, and consequently an improved castor, and an improved trolley with castors.

Accordingly a first aspect of the present invention provides a support structure for castors comprising a first member, a second member that is rotatable with respect to the first member about a pivot axis, and magnetic means that is operable upto a certain torque to restrain movement of the rotatable member from one angular position with respect to the first member.

Conveniently, said one angular position corresponds to a desired registration of the first and second members. In other angular positions the magnetic means may be operable to permit free rotation unless and until re-registration occurs. Additionally or alternatively the magnetic means may be operable to bias the rotatable member into said one angular position when displaced therefrom.

The first and second members may comprise first and second plates. The first and second members may be located in co-axial spaced apart relationship so as to provide mutually facing surfaces. Bearing means may be located between the first andsecond members.

The magnetic means comprises at least one magnet. Preferably the magnetic means comprises at least one permanent magnet. More particularly the magnetic means comprises at least one pair of magnetically co-operable components, which may be theaforesaid first and second members, separate components or at least one separate component. More preferably they are two separate components. When separate components are provided one component of at least one pair of magnetically co-operablecomponents is conveniently mounted with respect to each of said first and second members. More particularly a small air gap between the magnetically co-operable components creates a magnetic flux that provides said restraining effect.

A specific embodiment of the invention provides a support structure for castors, comprising: (i) first and second plates located in co-axial, spaced apart relationship so as to provide mutually facing surfaces, (ii) bearing means located betweenthe plates whereby one plate is rotatable with respect to the other plate, and (iii) one component of at least one pair of co-operable components being mounted on each plate, at least one of which pair of components is a permanent magnet adapted, in oneangular position of the rotary plate with respect to the non-rotary plate, to be brought into registration with a relatively small air gap between adjacent surfaces of the two co-operable components to create a magnetic flux that, up to a certain torquerestrains rotation, and in other angular positions without registration permits free rotation unless and until re-registration occurs.

When the co-operable components are in register, i.e. aligned opposite one another, the magnetic flux restrains rotation of the rotatable member so that, when applied to castors of, for example, a super market trolley, directional stability isachieved assisting steering of the trolley. Also, due to the use of magnetic flux to restrain rotation, there are no contact faces and no parts subject to wear. Clearly, the torque required to exceed the magnetic flux is a factor of the surface area ofthe magnet(s), and the air gap.

A second aspect of the invention provides castors suitable for a manually movable trolley and comprising a support structure according to the first aspect of the invention.

The castor comprises a wheel, roller or other ground engaging rolling element that is mounted rotatably with respect to a support bracket. Conveniently the support bracket constitutes or forms part of the aforesaid second (rotatable) member. Preferably the support bracket is U shaped. Most usually bearing means is provided between the first and second members. Preferably at least one ball or roller bearing is used.

A third aspect of the invention provides a trolley provided with at least one, and preferably four, castors in accordance with the second aspect of the invention.

Most usually the non-rotatable member is attached to a leg of the trolley by a bolt, the head of which engages an outer surface of the rotatable member via a second ball or roller bearing. The trolley may be a super market trolley, a rollcontainer, a patient trolley or any other wheeled conveyance provided with at least one castor for steering purposes. Preferably the trolley is manually movable.

Where provided the aforesaid first and second plates may be circular. Conveniently one of the first and second members, and preferably an upper one of the members, has an annular skirt or rim extending therefrom toward the other one of themembers. More preferably still the skirt shrouds a part of the other member. The skirt preferably encloses the magnetic means.

Where a pair of co-operable components is utilized one component of the pair may be a permanent magnet and the other component of the pair may be a ferro-magnetic element. Alternatively, both components of the pair may be permanent magnets. Thepolarity of the magnets may be such as to rely on attraction or repulsion to achieve the desired registration of the relatively movable members. The permanent magnets may be disc magnets, bar magnets, ring magnets or any other shape of magnet. Anyferro-magnetic element that is used preferably has a shape that is the same as or complimentary to the shape of the permanent magnet or magnets that are used. The ferro-magnetic element is preferably steel. In one embodiment discs are used for themagnetically co-operable components. In another embodiment the magnetically co-operable components are arcuate, and extend over a limited area in the form of a predetermined quadrant, e.g.