WO1998051557A1

WO1998051557A1 - A braking system for wheelchairs, wheeled walking frames and the like

Info

Publication number: WO1998051557A1
Application number: PCT/AU1998/000343
Authority: WO
Inventors: John William Bagnall
Original assignee: Individual
Current assignee: Individual
Priority date: 1997-05-09
Filing date: 1998-05-11
Publication date: 1998-11-19
Anticipated expiration: 1999-11-09
Also published as: AUPO672397A0

Abstract

A braking system for a wheel (112) of a wheelchair, wheeled walking frame or any other mobile load bearing frame has a brake pad actuating arm (108) which is pivotable about a pivot pin (110) which is at a first fixed reference location with respect to the wheel (112) and a brake pad (114) mounted on the actuating arm for frictionally engaging the wheel. There is a lever arm (116) which is pivotable about a pivot pin (118) which is at a second fixed reference location with respect to the wheel (112). A brake cable means (120) is connected to the lever arm (116) for pivotally moving the lever arm (116) from a first position to a second position where it urges against the actuating arm (108), the cable means (120) being manually operable by brake cable actuating means, such as a handbrake grip lever or touch lever arm operating a solenoid. Operation of the actuating means causes the cable means (120) to pivotally move the lever arm (116) to the second position against the force of a spring (100), whereby the actuating arm (108) is urged to pivotally move so that the brake pad (114) mounted thereon frictionally engages the wheel (112).

Description

A BRAKING SYSTEM FOR WHEELCHAIRS. WHEELED WALKING FRAMES

AND THE LIKE FIELD OF INVENTION The present invention relates to a braking system for wheelchairs, wheeled walking frames, as well as any other wheeled ambulatory aid used by infirm or invalid persons, and any other mobile load bearing frame. Although the invention is to be specifically described with respect to both a wheeled walking frame and a wheelchair, the scope of the invention is not to be restricted thereto, but is intended to embrace any mobile invalid supporting or load bearing frame having a manually operable braking system acting on one or more wheels of the frame. In the case of wheeled walking frames, such wheels will be swivel wheels being free to swivel about a full 360° without compromising the effective operation of the braking system. Accordingly, the invention has application also in food trolleys, mobile commodes and like mobile load bearing frames so as to improve the mobility and control thereof. BACKGROUND ART

Wheeled walking frames, also known as wheeled invalid walkers, are an effective ambulatory and recuperative aid for persons requiring a form of self-supporting crutch. Wheeled invalid walkers have numerous advantages over their immobile counterparts, not the least of which is a greater manoeuvrability. However, wheeled walkers are often found to be difficult to control by the person requiring support, particularly if such a user has significantly diminished balance or strength. Wheeled walkers may inadvertently roll or creep away from a desired stationary position whilst the user is obtaining balance against the walker, say, as the user grips on the walker to stand up.

For purposes of improved control, particularly of walkers having swivel type wheels, braking devices have been provided which act on the wheels to prevent undesirable movement of the walker away from a stationary position.

US Patent Specification No 4,029,31 1 discloses an invalid walker having a hand operated braking device acting on swivel-type wheels. Similar walkers are disclosed in UK Patent Specification No 2,261 ,1 73; Australian Patent Specification No 643,910 and Australian Patent

Specification No 47,805/96. Such walkers, however, are restricted in their manoeuvrability to the extent that their brake acting wheels are unable to swivel about a full 360°.

For instance, the invalid walker of US Patent Specification No 4,029,31 1 has a brake return tension spring that prevents a full and unimpeded swivelling of its swivel wheel about 360° or more, by virtue of the fixing of one end of the spring at an immovable location on the frame post for the swivel wheel.

There may be many occasions where it is desirous that the brake acting wheels be allowed to swivel about 360° or more whilst maintaining full operability of the braking devices therefor, say, where a user causes the wheels to swivel in the course of achieving a balance against the walker, or where subtle movement of the walker is required in tight locations.

Wheelchairs are widely used by persons unable to walk, such as those recovering from an immobilizing disorder and by those requiring a permanent means of mobility. Conventional wheelchairs have a pair of small diameter front swivel wheels and a pair of larger diameter rear fixed wheels. The most effective braking effect on such wheelchairs would be achieved by providing for the braking system to apply braking force to the rotation of the rear fixed wheels which have a greater diameter and therefore would have a greater torque, than the front swivel wheels. Wheelchair braking systems of the prior art have been generally of a directly acting type whereby the lever or the like upon which the user applies braking action also supports the brake pad which acts upon the wheel. Such braking systems are considered primitive in many other fields, such as in the automotive manufacturing industry, as they do not allow for a desirably high level of control or adjustment of the braking force.

Furthermore, known prior art wheelchair braking systems do not have the facility for readily removing a worn brake pad and replacing it quickly and easily with the new brake pad.

Such deficiencies of wheelchair braking systems are also present in many braking systems for wheeled walking frames.

It is therefore an object of the present invention to overcome the shortcomings of prior art braking systems for wheelchairs and wheeled walking frames. SUMMARY OF INVENTION According to the invention there is provided a braking system for a wheel of a wheelchair, wheeled walking frame or any other mobile load bearing frame, said braking system including:

(i) a brake pad actuating arm which is pivotable about a first fixed reference location with respect to said wheel, (ii) a brake pad mounted on said actuating arm for frictionally engaging said wheel, (iii) a lever arm which is pivotable about a second fixed reference location with respect to said wheel, (iv) a brake cable means connected to said lever arm for pivotally moving said lever arm from a first position to a second position where it urges against the said actuating arm, and

(v) brake cable actuating means adapted for manual operation, so that operation of the said actuating means causes the said cable means to pivotally move the said lever arm to the said second position, whereby the said actuating arm is urged to pivotally move so that the said brake pad mounted thereon frictionally engages the said wheel.

In a preferred form, the braking system includes a coil spring return means for providing pressure upon said lever arm so that it may resume its first position thereby providing clearance between said brake pad and said wheel when the said brake cable actuating means is not operated, said coil spring return means being in concentric alignment with the longitudinal axis of said brake cable means.

Preferably, the lever arm is independently rotatable about the longitudinal axis of the said brake cable means so as to enable the said wheel to swivel freely from any restriction or impediment imposed by location of the said cable means.

In a further preferred form, the cable is operable by a hand brake grip lever or by a touch lever arm actuating a solenoid. BRIEF DESCRIPTION OF THE DRAWINGS

In order that the invention may be readily understood and put into practical effect, reference will be made to the accompanying drawings, in which;- Fig. 1 is a side elevational view of a wheeled walking frame which includes a braking system according to a first preferred embodiment of the invention, Fig. 2 is a side elevational view of a wheeled walking frame which includes a braking system according to a second preferred embodiment of the invention, Fig. 3 is an exploded view of a hand grip assembly for the walking frame of Figs. 1 and 2, Fig. 4 is a side elevational view of a wheeled walking frame which includes a braking system according to a third preferred embodiment of the invention, Fig. 5 is an enlarged side view of a portion of the hand grip assembly for the walking frame of Fig. 4, Fig. 6 is a sectional front view through A-A of the assembly of Fig. 5,

Fig. 7 is a sectional side view through B-B of the assembly of Fig. 6, Fig. 8 is a side elevational view of a brake acting swivel wheel assembly of the walking frame of Figs. 1 , 2 and 4, Fig. 9 is a front elevational view of the brake acting swivel wheel assembly of Fig. 8, and

Fig 1 0 is an enlarged part sectional side view of part of the braking system for the swivel wheel assembly of Figs. 8 and 9. Fig 1 1 is a front elevational view of a wheeled walking frame which includes a braking system according to a fourth preferred embodiment of the invention,

Fig 1 2 is a side elevational view of the wheeled walking frame of

Fig 1 1 , is a front elevational view of a brake acting swivel wheel assembly of the walking frame of Figs 1 1 and 1 2, is a side elevational view of the swivel wheel assembly of Fig

1 3, is a part sectional front view of part of the braking system for the swivel wheel assembly of Figs 1 3 and 1 4, is a part sectional side view of part of the braking system for the swivel wheel assembly of Figs 1 3 and 1 4 with the brake pad not frictionally engaging the swivel wheel, is a view similar to that of Fig 1 6 with an unworn brake pad frictionally engaging the swivel wheel, is a view similar to that of Figs 1 6 and 1 7 with a worn brake pad frictionally engaging the swivel wheel, is a side elevational view of part of a preferred braking system of the present invention for a fixed wheel of a wheelchair, is a top view of the braking system shown in Fig. 1 9, is a sectional side elevational view of the braking system shown in Figs 1 9 and 20, is a top view of the brake pad used in the braking system of Figs. 1 9, 20 and 21 , is a left side view of the brake pad shown in Fig 22, is a front side view of the brake pad shown in Fig 22, is a sectional side elevational view of a handgrip and handbrake lever assembly showing a brake cable actuating means and brake lock system for the wheelchair braking system of Figs 1 9 to 24, as well as for the wheeled walking frame braking system of Figs 1 to 1 8, Fig 26 is a side elevational view of the hand grip and handbrake lever assembly shown sectionally in Fig 25, Fig 27 is a sectional side elevational view similar to that of Fig 25 showing the brake lock system in its locked position. Fig 28 is a side elevational view of an occupant operable braking system for a wheelchair according to another embodiment of the invention, Fig 29 is a top view of the braking system shown in Fig 28, Fig 30 is a side elevational view of another occupant operable braking system for a wheechair according to yet another embodiment of the invention, and

Fig 31 is a top view of the braking system shown in Fig 30. MODES FOR CARRYING OUT THE INVENTION

The wheeled walking frame 10 of Fig. 1 consists of a tubular frame assembly having a pair of extendable anterior posts (only right side anterior post 1 2 shown), a middle cross post (not shown) and a lower U-shaped cross post 1 3 and a U-shaped handle bar cross post 1 , each of which cross posts interconnect the anterior posts 1 2, a pair of frame support posts (only right side frame support post 1 6 shown) having a rearwardly extending portion 1 8 and a downwardly extending portion 20, and a pair of lower carriage posts (only right side carriage post 22 shown).

Extending downwardly from the rear end of the lower carriage posts 22 are a pair of rear wheel mount posts 26 which are formed continuously with their respective lower carriage post 22. A pair of front wheel mount posts 24 are weld connected downwardly from the front end of the lower carriage posts 22. The lower U-shaped cross post 1 3 is formed continuously with the pair of lower carriage posts 22, such that the cross post 1 3 and the pair of carriage posts 22 are originally a single post which is then formed into a U-shape member consisting of its component posts 1 3, 22.

The left side of the frame assembly is a mirror image of the right side shown in Fig. 1 .

The middle cross post and the U-shaped handle bar cross post 1 4 are connected by welding to the anterior posts 1 2 which are themselves connected by welding to the carriage posts 22. Each of the frame support posts 1 6 are connected at both of their ends to their respective anterior post 1 2 and carriage post 22 by welding. The frame assembly is supported on four swivel wheels, the two front wheels 25 being acted upon by a braking system, while the two rear wheels 23a are not adapted for braking. Each of the anterior posts 1 2 have a fixed position portion 28 and a movable portion 30 which is telescopically extendable therewithin so as to adjust the length of the anterior post 1 2. The movable portion 30 is secured at a desired position with respect to the fixed position portion 30 by the screwing of a bolt 32 through a threaded socket 33 providing access for the bolt 32 into the anterior post, whereby the bolt 32 may be urged rigidly against the movable portion 30. At each end of the U-shaped handle bar cross post 14 is a hand grip

34 and a conventional handbrake grip lever assembly 36. Each lever assembly 36 is operably connected by a first actuating cable 38 slidably located within a flexible sheath to a second brake cable 40 which operates the brake means shown in Fig. 10. Retraction of the first actuating cable 38 by gripping the lever 37 of assembly 36 causes the second brake cable

40 to be pulled upwardly. The conventional handbrake lever assembly 36 may be augmented or substituted by one or more touch lever arms mounted on the frame assembly.

A touch lever arm 44 is pivotally connected to portion 1 8 of support post 1 6 by a bolt 46. The arm 44 is held closely to the support post 1 6 by a retaining bolt and return coil spring arrangement 48 as shown in Fig. 3. There is an aperture (not shown) in the lever arm 44 through which the shaft of the retaining bolt passes, with the head of the retaining bolt being located at the underside of the lever arm 44. The maximum diameter of the retaining bolt head is greater than that of the aperture so that the lever arm 44 is restricted from pivoting downwardly beyond the distance provided by the length of the bolt shaft which emerges from the lever arm 44. The return coil spring is located concentrically around the bolt shaft and is adapted to abut at one of its ends against the upperside of the lever arm 44 and at the other of its ends against the underside of the support post 1 6. A microswitch 50 for activating a battery powered electrical circuit (located within the tubular frame members) is mounted on the support post 1 6 and is switched "on" when the user grips the lever arm 44 to pivot it upwardly against the pressure exerted by the coil spring. The microswitch 50 will remain "on" only for as long as it is being pressed by the lever arm 44. Release of the lever arm 44 by the user will allow the lever arm 44 to return under influence of the coil spring to its original position where the microswitch 50 is no longer being pressed and the electrical circuit is no longer being activated. When the microswitch is pressed to its "on" position, current will pass along the circuit and operate a solenoid 52 mounted on the anterior post 1 2. The solenoid 52 controls the upward pulling of the second brake cable 40, thereby enabling the touch lever arm 44 to ultimately operate the brake means shown in Fig. 10. The battery 54 is located within a cradle

56 mounted on the anterior post 1 2.

A second touch lever arm 58 is pivotally connected to the lower portion 20 of support post 1 6 by a bolt 59. The lever arm 58 operates similarly to the lever arm 44 via a microswitch and retaining bolt with return coil spring arrangement (not shown).

The wheeled walking frame 60 shown in Fig. 2 has an identical frame assembly as the walking frame of Fig. 1 , but differs in that (i) it lacks a conventional handbrake lever assembly mounted on the handle bar cross post 1 4, (ii) the two rear swivel wheels 25b are acted upon by a braking means rather than the two front swivel wheels 23b, (iii) the battery 54 is located within a cradle 56 mounted on the lower portion 20 of the support post 1 6, as is the solenoid 52, rather than on the anterior post 1 2, (iv) it lacks a second touch lever arm. There may be circumstances where a rear swivel wheel acting braking system, as shown in Fig. 2, is advantageous over the system shown in Fig. 1 .

The wheeled walking frame 62 shown in Fig. 4 also has an identical frame assembly as the walking frame of Fig. 1 , but differs in that the touch lever arms 44 and 58 are replaced by a single touch lever arm 64 which extends alongside the support post 1 6, thereby enabling the user to have greater accessibility to operate the braking means.

As shown in Figs. 5, 6 and 7, the touch lever arm 64 is sunk into a continuous groove extending along the underside of the support post 1 6 and is retained therein by the resilient nature of its component parts, particularly the outwardly projecting members 66, 67 which abut against the inside edge of the tubular frame 68. A plurality of tongue springs 70 are located within the frame 68, each of which provide a spring resistance against the movement of the lever arm 64 therewithin. There are also a plurality of microswitches 72 which are mounted on the support post 1 6 and which are activated when the user grips the lever arm 64 to pull it towards the frame 68 against the pressure exerted by the tongue springs

70. The operation of the microswitches 72 are identical to the operation of the microswitch 50 as described in relation to Figs. 1 and 3.

The brake acting swivel wheel assembly shown in Figs. 8, 9, and 1 0 consists of a wheel 74, a wheel housing 76 with axle arrangement 78 for allowing linear rotation of the wheel 74, a spigot bolt 80 for enabling simultaneous swivel action of the wheel 74 and housing 76, and a brake means (as shown enlarged in Fig. 1 0) which is part of the braking system of the present invention. The spigot bolt 80 is mounted within the wheel mount post 24 (as shown in Fig. 1 ) and has a hollow continuous bore 82 through which passes the second brake cable 40, the operation of which has been described above.

The brake means is independently mounted to the wheel housing 76 and so can swivel in concert with the wheel 74.

There is a brake pad actuating arm 84 upon which is mounted a brake friction pad 86 for frictionally engaging the periphery 85 of the wheel

74. The actuating arm 84 is pivotally connected by pin 89 to wheel housing 76, and there is a return spring 91 mounted at one end to the housing 76 and at the other end to the actuating arm 84 which provides a bias for the actuating arm 84 to move away from the wheel 74. The actuating arm 84 may be acted upon by a brake lever arm 90 which is pivotable about pivot pin 92 mounted to the wheel housing 76. The lever arm 90 has a pair of actuating arm adjusting screws 94 secured side by side through the lever arm 90, the heads 95 of which are adapted to press against the actuating arm 84 when the opposite end of the lever arm 90 is pulled upwardly by the pulling of the second cable 40. The pressing of the screw heads 95 against the actuating arm 84 causes the brake pad 86 to firmly contact the periphery 85 of the wheel 74, thereby restraining linear rotation thereof.

The second brake cable 40 has an enlarged end member or terminal head piece 96 that fits within a cavity 98 formed in the underside of the lever arm 90 so as to enable, when required, simultaneous upward movement of the second cable 40 and lever arm 90 but independent simultaneous swivel motion of the lever arm 90, actuating arm 84, wheel housing 76 and wheel 74 with respect to the second cable 40. The head piece 96 and cavity 98 thereby co-operate to provide a bearing type arrangement. There is a coil return spring 1 00 aligned concentrically along the longitudinal axis of the lower part of the second cable 40, and abutting, at its upper end, against the lower surface of the spigot bolt 80 and, at its lower end, against the upper surface of the lever arm 90. The cavity 98 and the coil return spring 1 00 around the lower part of the second cable 40 are aligned with the axis of swivelling of the wheel 74 and housing 76. The uppermost part of the second brake cable 40 (not shown in Figs.

8 to 1 0) is connected to an eyelet which is, in turn, connected to a vertical movement actuating member of the solenoid 52. This actuating member is also able to rotate on a bearing surface of the solenoid 52 about its vertical axis. When the second cable 40 is pulled upwardly by operation of the solenoid responding electrically to the gripping of the handbrake lever 37 or touch lever arms 44, 58, 64, any swivelling of the wheel 74 and housing 76 will not cause the second cable 40 to rotate about its longitudinal axis, but rather remain stationary. In this instance, the head piece 96 is serving as a bearing means allowing the lever arm 90, actuatint arm 84, wheel housing 76 and wheel 74 to simultaneously swivel independently of the second cable 40.

When the second cable 40 is not being pulled upwardly as mentioned above, any swivelling of the wheel 74 and housing 76 will cause the second cable 40 to rotate about its longitudinal axis. In this instance, the solenoid 52 is providing the bearing means for allowing the wheel 74 and second cable 40 to swivel independently of the location of the solenoid 52.

The wheeled walking frame 1 00 of Figs. 1 1 and 1 2 has a tubular frame that has been ergonomically designed to suit most users, but in all other respects it operates in a similar fashion to the walking frames of Figs. 1 to 1 0. It merely differs from the aforementioned walking frames in that it has side mounted battery packs 1 02, 1 03 and a rubber protected lower cross post 104. Adjustment of the height of the handle bar cross post 1 05 may be effected by operation of a pair of levers 106, 107. Although not shown, the battery packs may be mounted across the front of the lower cross post 1 04.

The brake acting swivel wheel assembly shown in Figs. 1 3 to 1 8 is similar in many respects to the assembly of Figs. 8, 9 and 1 0. Specifically, it includes a brake pad actuating arm 1 08 which is pivotable about a pivot pin 1 1 0 mounted on the wheel housing 1 1 1 and located at a first fixed reference location with respect to the wheel 1 1 2. There is a brake pad 1 1 4 mounted on the actuating arm 108 which is adapted to frictionally engage the wheel 1 1 2 and a lever arm 1 1 6 which is pivotable about a pivot pin 1 1 8 also mounted on the wheel housing 1 1 1 and located at a second fixed reference location with respect to the wheel 1 1 2. A brake cable 1 20 is connected to the lever arm 1 1 6 and is adapted to pivotally move the lever arm 1 1 6 from a first position, such as that shown in Fig. 1 6, to a second position, such as that shown in Figs. 1 7 and 1 8, where the lever arm 1 1 6 urges against the actuating arm 1 08 by pressure applied through the member 1 22. The brake cable actuating means is not shown but it can be any of the actuating means described with reference to Figs. 1 to 10.

Operation of the brake cable actuating means causes the cable 1 20 to move the lever arm 1 1 6 to the positions shown in Figs 1 7 and 1 8 so as to cause frictional engagement of the brake pad 1 1 4 with the wheel 1 1 2. The wheel 1 1 2 remains free to swivel about a full 360° and more by virture of the location of the cable 1 20 through the bore of the wheel mount post 1 24 and because of the enlarged end member 1 25 of the cable 1 20 which is independent of any rotational movementof the lever arm about the longitudinal axis of the cable.

The wheelchair braking means shown in Figs. 1 9 to 24 is part of a braking system that is similar to the braking system described wih reference to the walking frames in Figs. 1 to 1 8. Some simple adaptations have been made to suit the operation of the braking system to the fixed large diameter wheels of a wheelchair, namely, no part of the braking system needs to swivel or rotate since the wheel itself does not swivel, and the braking means is mounted to a fixed position with respect to the wheelchair frame so that it is forward of the wheel, rather than above the wheel as for the walking frame. Otherwise, the basic components and opertion of the wheelchair braking means as shown in Figs. 1 9 to 24 are generally similar to those of the aforementioned walking frames. A brake pad actuating arm 1 30 is pivotable about a pivot pin 1 32 which is mounted at a first location on a bracket 1 34 which is, in turn, mounted on a frame portion 1 45 of the wheelchair. There is a brake pad 1 36 mounted on a V-shaped member 1 37 which is welded to a fastening plate 1 38. The fastening plate 1 38 is fastened by bolts 1 39 through bolt receiving apertures 143 to the actuating arm 1 30. The brake pad 1 36 is adapted to frictionally engage the correspondingly profiled rubberized periphery 1 40 of the wheel 1 42. There is a lever arm 1 44 pivotable about pivot pin 1 46 which is also mounted on bracket 1 34 but at a second location thereof. A brake cable 1 48 is removably connected to the lever arm 1 44 and is adapted to pivotally move the lever arm 1 44 from a first position, such as that shown in Fig 21 , where the wheel 1 42 is free to rotate, to a second position, where the lever arm 1 44 urges against the actuating arm 1 30 by pressure applied through the member 1 49. The brake pad 1 36 may by positioned lower down the actuating arm 1 30 than is shown (with suitable adjustment of the position of the lower bolt) . Some subtle adjustment of the position of the bracket 1 34 may be required in that case. A differently profiled wheel periphery will also require a different brake pad receiving face shape to the one shown in Fig. 22. The brake cable actuating means is shown in Figs 25, 26 and 27 which also show a ratchet-type brake lock system, to be described in more detail later.

Operation of the brake cable actuating means is effected by the user, in this case, the wheelchair attendant, gripping the hand grip 1 60 and the handbrake grip lever 1 62 so as to bring them closer together. The lever

1 62 is pivotally attached by pivot pin 161 to casing 1 63 and, during its pivotal movement, drags a link member or grub screw 1 64 which is connected to a cable 1 48 slidably located within a flexible sheath 1 65. The sheath 1 65 and its enclosed cable 148 are protected from excessive rubbing against any component of the casing 1 63 by being located in an arched passageway formed in the casing 1 63. When the lever 1 62 is gripped by the user, the cable 1 48 is drawn rearwardly through its sheath

1 65 which causes the lever arm 1 44 to pivotally move as described above which, in turn, interacts with the actuating arm 1 30 to apply braking foce ont he wheel through the brake pad 1 38.

Enclosed within the casing 1 63 is a ratchet-type brake lock system consisting of a ratchet-type member 1 66 pivotally connected by pin 1 67 to the casing 1 63 and biased by return spring 1 68 so as to resume the position as shown in Fig. 25 when no undue force is applied. The member

1 66 may be moved to the position shown in Fig. 27 by the user moving the arm 1 69, which is attached to and movable with the member 1 66, but which is located on the outside of the casing 1 63 for user access. In the engaged position shown in Fig. 27 the teeth 1 70 of the ratchet-type member are meshingly engaged with the teeth 172 of the adjacent surface of the lever 1 62 and are unable to be released therefrom by virtue of the preset angulation of the teeth. With the member 1 66 in the position shown in Fig. 27, the brake pad is held lockably against the wheel periphery and the wheel is unable to rotate. Disengagement may only occur when the lever 1 62 is raised slightly so as to provide a clearance between the two sets of teeth, whereupon the member 1 66 will resume its original position under influence of the return spring 1 68. The wheelchair may also include a braking system according to the present invention which is operable by the wheelchair occupant, rather than the wheelchair attendant. Two such systems are shown in Figs. 28 to 31 . The first such braking system shown in Figs. 28 and 29 consists of a hand grip operated mechansim 171 located on a horizontal frame member 1 73 which is situated below the wheelchair seat.

When the lever 175 is pivotally moved by the user about pivot pin 1 79 it draws the cable 1 76 (enclosed in flexible sheath 1 77) which initiates the series of pivotal movements between lever arm and actuating arm described earlier so that the brake pad 1 86 can engage against the wheel periphery 180. The bracket 182 which supports the lever arm and actuating arm is supported on underlying frame 1 84 via support means 1 83. A ratchet-type brake lock system may also be present to augment its operation for the benefit of the wheelchair occupant. Fig. 29 shows a circularly profiled wheel periphery and the correspondingly profiled brake pad 1 86.

Figs. 30 and 31 show an occupant operable braking system that is electromagnetically controlled, rather than being handgrip lever with draw cable controlled. The occupant grips the touch bar 1 89 which activates the switch 1 90 and sends an electrical impulse via wire 1 91 to the solenoid 1 92. A battery 1 93 powers the system. The solenoid controls the movement of a cable located in sheath 1 95. The manner in which the solenoid and cable control the action of the brake pad on the wheel periphery is similar to that of the braking means described earlier.

The above mentioned braking systems for a wheelchair and wheeled invalid walker allow the user to exercise a high level of control over the braking force to be applied by virtue of the arrangement of lever arm and actuating arm working in concert and in response to the movement of the cable. In particular, there is am enhanced mechanical advantage provided by the juxtaposition and pivotal interrelationship of the lever arm and actuating arm, both of which are mounted in fixed locations with reference to the wheel upon which they act. This mechanical advantage is particularly helpful to disabled, infirmed and geriatric users.

Furthermore, the lever arm is swivelable, in the case of swivel wheels for wheeled walking frames, with the wheel, and the cable which connects to the lever arm does not swivel therewith, but rather allows the lever arm, and hence the wheel, to freewheel about the cable. Various modifications may be made in details of design and construction without departing from the scope and ambit of the invention.

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:-

1 . A braking system for a wheel of a wheelchair, wheeled walking frame or any other mobile load bearing frame, said braking system including:

(i) a brake pad actuating arm which is pivotable about a first fixed reference location with respect to said wheel,

(ii) a brake pad mounted on said actuating arm for frictionally engaging said wheel,

(iii) a lever arm which is pivotable about a second fixed reference location with respect to wheel,

(iv) a brake cable means connected to said lever arm for pivotally moving said lever arm from a first position to a second position where it urges against the said actuating arm,

2. The braking system of claim 1 including a coil spring return means for providing pressure upon said lever arm so that it may resume its first position thereby providing clearance between said brake pad and said wheel when the said brake cable actuating means is not operated, said coil spring return means being in concentric alignment with the longitudinal axis of said brake cable means.

3. The braking system of claim 1 wherein the lever arm is independently rotatable about the longitudinal axis of the said brake cable means so as to enable the said wheel to swivel freely from any restriction or impediment imposed by location of the said cable means.

4. The braking system of claim 1 wherein the cable is operable by a hand brake grip lever or by a touch lever arm actuating a solenoid.