GB2147802A

GB2147802A - Improvements in and relating to castors

Info

Publication number: GB2147802A
Application number: GB08327464A
Authority: GB
Inventors: John Philip Gear
Original assignee: Revvo Castor Co Ltd
Current assignee: Revvo Castor Co Ltd
Priority date: 1983-10-13
Filing date: 1983-10-13
Publication date: 1985-05-22
Also published as: GB8327464D0; GB2147802B

Abstract

A castor has a wheel carrier (1) pivotal about mounting element (9) which is engageable with a vehicle, being a trolley or truck or whatever is to be movably supported. A deformable braking member (13) is mounted on the carrier and is deformable by an operating arm (20) pivotally carried by the wheel carrier. Movement of the arm (20) in one sense deforms the member (13) urging a first part (21) of the braking member against the wheel (W) and another part (19) into locking engagement with the mounting element, movement of the operating arm (20) in the opposite sense freeing the wheel and carrier for rotation about their respective axes. <IMAGE>

Description

SPECIFICATION Improvements in and relating to castors This invention is concerned with improvements in and relating to castors and more particularly to castors having a parking brake facility.

There have been a number of proposals for braking a castor wheel for parking purposes having the facility of not only holding the wheel against rotation about its rolling axis but also holding the wheel carrier against rotation about the axis about which the castor wheel carrier is pivotal relative to the item being supported, e.g. a vehicle or an article of furniture (hereafter referred to as "the vehicle").

One such proposal has an inverted U-section wheel carrier between the arms of which the wheel is located, the carrier being provided in its upper bridging wall with bearing surfaces on which run balls retained on those surfaces by races carried by a castor mounting pin engageable with the vehicle.

Within the wheel carrier is mounted a lever just below the bridging wall, the lever being pivotal on a spindle offset relative to the mounting pin and parallel with the wheel axis. The lever is pivoted by a foot operable cam, carried by the wheel carrier and movable to press that end of the lever remote from the mounting pin axis to urge the lever against the wheel to thereby brake the wheel against rolling rotation. Upon such movement the other end of the lever engages a serrated member rotationally fast relative to the mounting pin which results in locking of the wheel carrier against movement about the mounting pin axis.The cam is shaped so that, when it is moved by application of a force from a free' position to press the lever into the braking attitude, it will lock relative to the wheel carrier in a braked position and so that when moved by a force acting on the cam in a different direction the cam returns to a free position and the lever will be released from the wheel and from the serrated member.

According to one aspect of the present invention there is provided a castor comprising a wheel carrier, a wheel carried by the wheel carrier, bearing means on the wheel carrier for rotation of the wheel carrier about a mounting element which can be made rotationally fast relative to a vehicle as herein defined, a resiliently deformable braking member mounted on the wheel carrier and an operating arm, pivotal about an axis parallel with the wheel axis, movement of that arm in one sense from a free position to a braking position deforming the braking member and bringing a first part of that member into braking engagement with the wheel and a second part into mechanical locking engagement with the mounting element to hold the wheel carrier against angular movement relative to the mounting element, movement of the operating arm in the opposite direction unlocking the second part of the deformable braking member relative to the mounting element and disengaging the first part of the deformable member from the wheel.

Further features and advantages of the present invention will appear from the following description of two embodiments thereof, given by way of example only, reference being made to the accompanying drawings in which: Figures 1 and 2 are part sectioned elevations of one embodiment of this invention in the free and braked conditions respectively.

Figures 1 and 2 show a wheel carrier 1 of inverted U-section having side walls, such as 2 and a top wall 3. A wheel W being rotatably mounted in the carrier. The carrier top wall defines tracks 4 for upper balls 5 and lower balls 6 which are retained by races 7, 8 fast with a mounting element 9 which will non-rotatably engage the vehicle (not shown) by means of, for example, a bolt. Lower race 8 is arranged to be rotationally fast with the mounting element 9 and has serrations 11.

Anchored to the top wall 4 at 12 is a resiliently deformable member 13 which is a resilient strip having one end 14 of V-form and terminating in lip 15, at an acute angle to the adjacent limb of the Vform and the other end bifurcated by a central part 16 bent back to form an anchor piece leaving two spaced arms 18 each defining a step 18a and having a turned up end to form a lip 19.

In Figure 1 the member 13 is in the free condition where an inverted U-section operating arm 20 having a foot pedal 20a pivoted about the wheel axis is in a first free position in which the member 13 retains the arm and damps any rattle or movement of that arm. If arm 20 is pivoted clockwise as viewed in the drawings, the part 14 of the member 13 is depressed until a brake pad 21 bears on the wheel periphery as shown in Figure 2, thereby braking the wheel against rolling rotation. The arm will stay in the braking position when lip 15 engages an aperture 22 in the arm 20. That movement of the arm 20 to the braking position also causes the lips 19 on arms 18 of member 13 to engage serrations 11, member 13 during the braking and locking movement undergoing resilient deformation including a pivoting action at the region of the root of the bifurcation.

The arm 20 may be released by moving it anticlockwise back over V-form part 14.

The above described embodiment lends itself to a facility whereby a basic castor, having no braking facility is produced having a wheel carrier, wheel, mounting element, a top wall 3 provided with an integral apertured haunch 27 and a locking piece can readily be modified.

To modify that basic castor to one having a braking and locking facility, a kit of parts could be provided in order to make the conversion which will be possible without dismounting the castor. This kit will comprise an arm 20, a pair of bearings and a bolt to mount the arm 20 in the wheel bearings, a member 13 and a bolt or rivet to anchor that member on the haunch.

The end 14 of member 13 and the arms 18 are shaped as shown to provide appropriate shape and strength for positive locking.

The foot pedal 20a preferably has a dip moulded pad 20b.

Instead of securing the mounting element 9 to the vehicle by means of a bolt or the like, there may be provided a top plate 9a, shown in broken lines in Figure 1, rotationally fast with member 9 and having apertures 9b for receiving screws, bolts or the like engageable with the vehicle.

Claims

1. A castor comprising a wheel carrier, a wheel carried by the wheel carrier, bearing means on the wheel carrier for rotation of the wheel carrier about a mounting element which can be made rotationally fast relative to a vehicle as herein defined, a resiliently deformable braking member mounted on the wheel carrier and an operating arm, pivotal about an axis parallel with the wheel axis, movement of that arm in one sense from a free position to a braking position deforming the braking member and bringing a first part of that member into braking engagement with the wheel and a second part into mechanical locking engagement with the mounting element to hold the wheel carrier against angular movement relative to the mounting element, movement of the operating arm in the opposite direction unlocking the second part of the deformable braking member relative to the mounting element and disengaging the first part of the deformable member from the wheel.

2. A castor according to Claim 1 in which the resiliently deformable braking member comprises a resilient strip which each adjacent end includes a lock portion, one engageable with the mounting element and one engageable with the operating arm when that arm is in the braking position.

3. A castor according to Claim 2 in which the lock portion and mounting element define interengageable projection means and recess means which hold the wheel carrier against rotation relative to the mounting element.

4. A castor according to Claim 2 or Claim 3 wherein the lock portion engageable with the operating arm and that arm define an interengageable projection means and recess means engageable to hold the first part of the braking member against the wheel in the braking position of the arm.

5. A castor according to Claim 4 in which the strip includes a formation which the operating arm engages as it is moved toward the braking position and through which the arm urges the second part of the braking member against the wheel.

6. A castor according to any of Claims 2 to 5 in which the strip is anchored to the wheel carrier by way of a portion of the strip which is displaced from the strip at a region between the ends of the strip.

7. A castor according to Claim 6 in which the strip is bifurcated at that end which engages the mounting element, the anchor portion of the strip being that part of the strip between arms of the bifurcated part which has been turned back upon itself and secured to the mounting element.

8. A castor substantially as herein described with reference to the accompanying drawings.