NZ195628A - Drive unit for wheelchair:friction drive or braking - Google Patents

Description

195628 PATENTS FORM NO..5 No.: 195628 COMPLETE SPECIFICATION PATENTS ACT 1953 Date: 24 November 1980 1 ;S Complete After Provisional A DRIVE CONTROL UNIT I, ERIC WILLIAM BOND of 52 Chesterton Street, Johnsonville, Wellington, New Zealand a British subject and New Zealand citizen, hereby declare the invention, for which I pray that a Patent may be granted to me and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to a drive control unit and more particularly but not exclusively to a drive control unit for a wheel chair.

Whilst the present invention will hereinafter be described particularly with reference to its application in the provision of a drive to a wheel chair it will be appreciated by persons skilled in the art that numerous other uses would be possible.

It is an object of one embodiment of the invention to provide a drive control unit which in a speedy and efficient manner can control the drive to the wheels of a wheel chair for example.

According to one embodiment of the invention there is thus provided a drive unit for a wheel chair comprising: (a) a housing adapted for pivotal mounting on a frame work of a wheel chair; (b) a drive means providing a rotating drive having opposite ends thereof extending externally of said housing; (c) said drive means at each of said ends being adapted in use to be engageable with and drive a respective wheel of the wheel chair; (d) braking means extending outwardly from said housing on either side thereof and adapted, in use, to be engageable 195628 with a respective one of said wheels; (e) a mounting means enabling said housing to twist relative to its pivotal mounting when mounted on said frame work; whereby said drive means movable with said housing can in -Steering the wheelchair engage a selected one of said wheels while said braking means also movable with said housing can on the opposite side of said housing engage with the other said wheel.

The present invention will now be described by way of example with reference to the accompanying drawings wherein: FIGURE 1: shows, diagramatically, a front view of a wheel chair including a drive control unit according to one embodiment of the invention; FIGURE 2: shows a view from the side of the wheel chair of Figure 1; FIGURE 3: shows a rear underneath view of one end of the drive unit of the preceding figures; FIGURE 4: shows a front part-sectioned view of the drive unit of Figure 3 but including additional gearing; FIGURE 5: shows, schematically, a side view of the drive unit of the preceding Figures; FIGURE 6: shows a diagrammatic part-sectioned view of a control mechanism for the drive unit of the preceding figures; FIGURE 7: shows, diagrammatically, the drive unit of the preceding figures in association with the control mechanism of Figure 6. 195628 Referring to the accompanying drawings, in Figure 1 and 2 a wheelchair 1 is shown with a seat 2, armrests 3, front wheels 4, rear wheels 5, foot racks 6 and rear wheel grip 7.

A drive control unit according to one embodiment of the invention is referenced generally by arrow 8 and is shown fitted on the framework 11 of the wheelchair 1.

The unit 8 is shown comprising a housing or casing 9, pivoted at pivotal points 10 on the framework 11. To this end a shaft 12 has outer ends thereof extending externally of the housing 9 with spring-loaded pins 13, operable by means of triggers 14, able to be accommodated within a mounting provided on either side of the framework 11.

The housing 9, mounted on shaft 12 as hereinafter described, is thus able to pivot forwardly or rearwardly relative to the framework 11 about the pivot points 10 as indicated by the arrows A-A in Figure 5.

Within the housing 3, see Figure 3 especially, the shaft 12 passes through a tubular mounting 15 pivotally rotationally secured to the housing 9 by means of a pin or bolt 16 such that the housing 9 can twist and rotate about the mounting 15.

Suitably a resilient surround such as a rubber ring 83 is provided about the pin or bolt 16. 195628 The mounting 15, suitably be packed with grease, together with the mounting, described below, of a lever 18 relative to the housing 9, enables the housing 9 to twist relative to the longitudinal axis of the shaft 12 and thus to the framework 11. In this way as well as the housing 9 having a rearward and forward tilting facility about the pivot points 10, the housing 9 is also able to twist or rotate about a lateral and vertical plane as indicated by arrows B-B in Figure 5. In particular, one side of the housing 9 can be raised relative to its other side for the purpose which will hereinafter become clear. The housing 9 is shown having on either side thereof a cut-away portion 17 allowing for the twisting of the housing sides about the shaft 12 extending outwardly therefrom.

The lever member 18 is shown, in Figure 3 particularly, having a free end 21 provided with an over-sized or enlarged aperture 22 through which a pivot pin or the like 23 can extend from a side wall portion 24. This dimensioning of aperture 22 and pin 23 again enables the twisting of the housing 9, relative to the fixed axis defined by the shaft 12, to take place. An opposite end of the lever 18 is shown with a transverse member 25, knurled at 26, and secured with the lever 18 by means of a bolt of the like 27. The bolt 27 is shown off-centre relative to the longitudinal axis of member 25. In this way the member 25 can by rotation in its mounting on the lever 18 have its position on the lever 18 adjusted so as ■ •• 195628 to provide a corresponding adjustment of the braking provided by the member 25.

The lever 18 together with its boss 19 and a web 20 accommodates the shaft 12 along part of its length, the lever 18 being able to rotate about the shaft 12.

Also extending outwardly from the housing 9 through a bearing or race 58 is shown a shaft 28 having a respective free end 29 on either side of the housing 9 which may suitably be splined or grooved and thereby be adapted to transmit a frictional driving force to a respective wheel 5 upon rotation „ As shown in Figure 4 a sleeve 8Q can be fitted over each shaft end 29, the sleeves 80 having internal splines or grooves 82 to mate with those of the respective end 29 and external splines or grooves 81 to transmit the drive to the respective wheel 5. The outside diameter of the sleeves 80 is chosen to give the required gearing of the drive to the wheels.

The shaft 28 as seen from Figures 3 and 4 particularly is driven by means of a drive arrangement including; a motor 30, a drive pulley 34 secured to the motor shaft by means of drive boss 33, drive belts 37, a large diameter driven pulley 36, and a boss 35 secured to the shaft 28. Operation of the motor 30 will thus provide a constant shaft rotation through the pulleys 34 and 36, the reduction ratio suitably being of the order of 3:1 from a speed of 3000 r.p.m.; the drive can then be applied through one or both ends 29 of the shaft 28 to one or both of the wheels 35.

The lever 18 also has, as shown particularly in Figures 3 and 5, an arm 38 having a groove or channel 39 extending therethrough from an underside surface thereof.

The groove 39 can accommodate the free end of a respective 195628 cable 41, 41' which may be prevented from leaving by means of an adjustable retaining stop 42, which can further adjust the position of the lever 18 correctly relative to the housing 9 and wheel 5. To the rear of the housing 9 and the pair of levers 18 is shown positioned a battery support or holder 4 3 having a battery 45 mounted thereon. At a front end of the support 43 a pair of hooks 44 can be provided one on either side thereof which hooks 44 can be hooked over respective lever arms 38. The rearward side of the support 4 3 may suitably be secured in suitable manner to the framework 11 and may be associated with battery charging and other ancilliary equipment (not shown).

The weight of the battery 45 acting on the support 4 3 ^nd arms 44 is utilized to hold the levers 18 in a position in which the ends 29 of the shaft 28 are both engaging respective wheels 5 to drive same. To remove the frictional engagement of the drive ends 29 from the respective wheels 5 the cables 41 can be operated jointly or singly which will raise a respective lever 18 and in so doing will space the respective drive ends 29 ' from the wheel 5. That can also frictionally engage the end 26 of the braking means 25 on that same side with a respective wheel.

If the wheelchair 1 is required to be turned then an appropriate one of the cables 41 can be pulled so that while drive from a drive end 29 is maintained on one wheel 5 the other wheel has the drive taken off and the braking means 25 applied. 195628 Referring particularly to Figures 6 and 7 the control of the drive to the wheels 5 is shown provided by means of a control unit 47. This is shown having a switch 56 by means of which power from the battery 44 to the motor 30 through the leads 64, 6 3 can be switched on or off. With the switch 56 in the on position the motor drive can be further controlled by means of a control arm 49 manually operated by the person sitting in the wheel chair. The control arm 49, pivoted at 57 to the unit 47, is shown in Figure 6 having a slide 52 which can engage beneath a top wall of a rear plate 50 of the unit 47, a front wall 48 being secured to the rear wall 50 by means of bolts or screws 51. The arm 49 between its front and rearward positions can control a switch 53 and provide a reversal of the voltage polarity applied to the motor and thus the direction of movement of the wheel chair 1. Suitably, the front position of the arm 49 will provide a forward movement of the wheel chair 1 while in its rear position the arm 49 will provide a reverse movement of the wheel chair 1. In the substantially central position shown in Figure 6 this may represent a no-voltage position at which the wheel chair is effectively in "neutral" with again no drive being applied to the wheels 5. The switch assembly 53 which may be of any suitable type is shown having electrical leads 54 connected thereto through the switch 56 and including a fuse 55.

The back plate 50 of the assembly 47 is shown connected at its top and bottom with the free ends of the cables 41 and 41' which are prevented from leaving the rear plate 50 by means of suitable stops or abuttments 46. If, as is shown in Figure 7, the cable 41' is connected at the top of the back plate 50 and the cable 41 is connected at the bottom, movement of the arm 49 away from the wheel chair 1, i.e. to the right, will result in the drive to the right hand wheel 5 being taken off and braking applied thereto so that a turn to the right results. Conversely movement of the arm 49 to the left, i.e. towards the wheel chair, will apply a force to the cable 41' to cause a braking of the left hand wheel 5 and a turn to the left. To enable the total sideways movement of the assembly 47 in the direction of arrow C in Figure 1, its rear plate 50 is shown provided with a pair of brackets 68, 69 whilst a bracket assembly 60 may be attached to the wheel chair framework 11. A pair of off centre cam-like members 61 and 61' operated by lever 59 are accommodated by respective brackets 68 and 69 while a shaft connecting the two members 61, 61' can be accommodated by the bracket assembly 60.

Due to the action of the members 61, 611 operation of the lever 59 causes a degree of transverse movement of the plate 50 towards or away from the bracket .60 and the framework 11 and thus applies force to both cables 41, 41' at the same time. This results in both wheels being released from both braking and driving forces and allows the wheel chair to be pushed. In the drive position of the lever 59 operation of one of the cables 41, 41' for steering purposes will be obtained by the sideways tilting of the assembly 47, its brackets 68, 69 rotating about the shaft connecting the members 61 and 61'.

To summarize therefore, with the switch 56 in its on position power from the battery 45 via leads 64 to the motor 30 provides a continuous rotation of the shaft 28. With 195628 the control arm 49 in either its forward or reverse positions this provides a corresponding forward or reverse motion of the wheel chair 1. If however a sideways movement of the control assembly 4 7 has been effected by a sideways pushing or pulling action on the control arm 49 then a turn to the right or left can be achieved, a respective cable 41, 41' overcoming the weight of the battery 45 acting on a respective lever 18 and applying the braking member 25 to that particular wheel. To achieve this braking of a single wheel the housing 9 is able to twist about the pivotal mounting points 10 by means of a shaft support assembly 15 and the pivotal arrangement 22, 23 for the lever 18.

Operation of a lever 59 may also disengage both driving and braking of the wheels 5 when required.

Whilst an electric motor 13 has been described hereinabove it is to be appreciated that alternative drive means and alternative control arrangements, for example hydraulic, could be alternatively provided.

The control assembly 8 of the present invention requires minimal adaptation of an existing wheel chair prior to its being fitted thereto. The adaptation may essentially comprise merely the provision of suitable mounts on the framework 11 in which the spring-loaded pins 13 may be inserted.

Although this invention has been described by way of example with reference to one possible embodiment thereof it is to be understood the modifications and improvements may be made thereto without departing from the scope of the invention as defined in the appended claims.

Claims (12)

WHAT I CLAIM IS:

1. A drive unit for a wheel chair comprising: (a) a housing adapted for pivotal mounting on a frame work of a wheel chair; (b) a drive means providing a rotating drive having opposite ends thereof extending externally of said housing; (c) said drive means at each of said ends being adapted in use to be engageable with and drive a respective wheel of the wheel chair; (d) braking means extending outwardly from said housing on either side thereof and adapted, in use, to be engageable with a respective one of said wheels; (e) a mounting means enabling said housing to twist relative to its pivotal mounting when mounted on said frame work; whereby said drive means movable with said housing can in steering the wheel chair engage a selected one of said wheels while said braking means also movable with said housing can on the opposite side of said housing engage with the other said wheel.

2. A drive unit as claimed in Claim 1 wherein the pivotal mounting means for said housing comprises a shaft extending therethrough, a mounting means provided about said shaft and secured with.said housing to provide a pivotal and rotational mounting of said housing relative to said shaft.

3. A drive unit as claimed in Claim 2 wherein said mounting ccnprises a tubular merrber through which said shaft passes, a bolt or pin pivotally and rotaticnally securing said housing with said 1 n c; / o Q I s O (— o T 11 mounting, a resilient surround provided for said bolt or pin in its securement within said mounting.

4. A drive unit as claimed in Claim 3 wherein said braking means comprises a lever rotatably mounted about said shaft and having at one end an oversized aperture accommodating a pivot pin extending from said housing, an opposite end of said lever including a transverse member adapted to frictionally engage with, to brake,a respective one of said wheels.

5. A drive unit as claimed in Claim 4 wherein said tranverse member is connected with said lever by an off-centre securement means whereby the position of said transverse member relative to said lever can be adjusted in controlling the braking effect.

6. A drive unit as claimed in Claim 4 or Claim 5 wherein said lever includes a slot or groove accommodating a free end of a cable which can control the raising and lowering of the lever and the application of said braking means or said drive means to a respective wheel.

7. A drive unit as claimed in Claim 6 wherein said drive means comprises a shaft extending through bearing means outwardly from either side of said housing and movable with said housing to engage or disengage the drive to a respective wheel.

8. A drive unit as claimed in Claim 7 wherein a sleeve is provided to extend over the end of each of said drive shafts to increase the effective diameter thereof thus gearing the drive to the wheels.

9. A drive unit as claimed in Claim 8 wherein said drive J C i ^ shafts are driven by an electric motor, a battery mountable —> oh ? <£// °n said framework providing a power supply therefor , a ^ 3X - 12 - 'I» 195628 support for said battery being engaged with a respective lever on either side of said housing to apply weight thereto moving said housing and said drive shafts to a position at which said drive shafts are both frictionally engaged with a respective wheel.

10. A drive unit as claimed in Claim 9 wherein each cable of a respective lever is connected with a control unit movably mounted on said framework, one of said cables being connected to a top of said unit and the other of said cables being connected to a bottom of said unit, means to release said drive unit from a position adjacent said framework so as to apply tension to both the said cables and to release both said drive and brake means from said wheels, a control lever operable to reverse the direction of polarity of the voltage applied to the electric motor and to also pivot said control unit relative to said framework to apply tension on a selected one of said cables whereby drive is applied to one wheel and the braking means is applied to the other wheel to thus steer the wheel chair.

11. A drive unit as claimed in Claim 10 wherein said releasing means comprises a lever operate to rotate a pair of cam members against the back of the control unit to move it away from said framework in tensioning both said cables.

12. A drive unit substantially as herein described with reference to the accompanying drawings. ERIC WILLIAM BOND By his attorneys, BALDWIN, SON & CAREY - 13 -