Hand truck World

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.

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