SPECIFICATIONModular wheel chairBACKGROUND OF THE INVENTION 1. Fieldofthe inventionThis invention relates to a wheelchair. More particularly relates to a modular wheelchair comprising three interlocking modules, embodiments of each of the modules being interchangeable with other embodiments of the same module.
2. Description of the prior artThere is a recognised need for a wheelchair which has interchangeable components to enable itto be used for persons of different degrees of disability. A person with the highest degree of disability requires a chair which can be operated automatically and which has the lowest centre of gravity. A middle class of disability involves the need for a wheelchair which can be operated by an attendant and which has a middle height of centre of gravity and a third type of chair is one in which the disabled person is able to operate the chair himself, such a chair having relatively, the highest centre of gravity.
Accordingly it is an object of this invention to go some way towards achieving this desideratum or at least to provide the public with a useful choice.
SUMMARY OF THE INVENTIONAccordingly the invention may be said broadly to consist in a modular wheelchair comprising:a first module having a main frame and at least one associated wheel,a second module comprising a first sub-frame and a pair of associated wheels,a third module comprising a seat and a second sub-frame, andinterlocking means for locking together said first, second and third modules, the arrangement being such that in use a wheelchair may be assembled by interlocking said modules.
In a first alternative said second module comprises a pair of wheels each having circular hand rails rotary therewith the arrangement being such that the centre of gravity is relatively high and rearward.
In a second alternative said second module includes a pair of wheels of smaller diameter than in said first alternative, the centre of gravity of said second alternative being relatively central.
In a third alternative said second module includes a pair of wheels and a driving means for said wheels, the centre of gravity of this third alternative being relatively to the front and lower than in the first and second alternatives.
Preferably there is provided first interlocking means between said first module and said second module, a male member being on said second module and a female member being on the said first module.
Preferably there is provided a second interlocking means between said third module and said first module, the interlocking means comprising a retaining member from said third module interlocking with a recess in said first module and a catch for securing said third module to said first module.
The invention consists in the foregoing and also envisages constructions of which the following gives examples.
BRIEF DESCRIPTION OF THE DRAWINGSThe invention may be more fully understood by having reference to the accompanying drawings wherein:Figure 7 is an exploded view of one alternative embodiment of the invention,Figure 2 is an exploded view of the first and second modules in another alternative of the invention,Figure 3 is a perspective view of the second module according to the invention showing the first sub-frame.
Figure 4 is a detailed perspective view of the remote control of said one alternative embodiment,Figure 5 is a detailed exploded view of the battery charger and control mechanism,Figures 6 and 7 are respectively front and side elevations of a braking mechanism for use in the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTReferring to Figures 1 and 2 the first module 10 of the invention comprises a backbone 18 having side members 20 protruding therefrom and hollowed out portions, the front of which is an interlocking member receiving recess 21. Backbone 18 and side members 20 are cast out of the same piece of aluminium. Female recesses or bores 22 are provided in the backbone 18 for receiving corresponding male members 23 or 23a for interlocking the first module with the second module in a manner which will be explained hereinbelow. Locking bar 26 is rotating within a bore in backbone 18. Handle 27 is provided to rotate bar 26.
At the bottom of each side member 20 there is a bore to receive the pins 45 of sprung castors 46 which are fitted as indicated by arrows F. Small pneumatic tyres as are well known in the art are provided in castors 46.
There are three alternative embodiments for the second module illustrated in the lower left hand corner of Figure 1 and in Figures 2 and 3. Referring toFigures 2 and 3 the main component of the second module 16, first and second alternatives comprises a main cross frame member 56 and a pair of longitudinal members 58. At the rear of longitudinal members 58 are a pair of bearings 62 and 64 for receiving different sets of rear wheels. Foot pedals 66 are provided at the rear of members 58. At the front of the longitudinal frame member 58 is a slot 60. Male members 23a are provided to interlock frame cross member 56 with backbone 18 of the first module.
Referring to Figure 1 the first sub-frame 14 of the third alternative, second module comprises a fibreglass basket 48. Projecting frontwardly from the basket are a pair of male interlocking members 23 which correspond with the bores 22 of the first module. It will be seen that there are a pair of recesses 24 whose radius of curvature corresponds with the circumference of bars 26 in the first module.
There is fitted in the basket 48 two electric motors 52, for example that for use on a windshield wiper of a large truck. Also illustrated is a control box 50, the details of which are more fully set out hereinbelow.
A pair of wheels 54, only one of which is illustrated for clarity, are provided. Wheel 54 is driven by motor 52.
The third module 12 of the wheelchair according to the invention comprises a seat 32 made, for example, of polypropylene and covered with a suitable padded fabric. This seat is mounted on the base portion 28 of the second sub-frame. In side view the base portion 28 has an L-shape, the stem of the L supporting the seat. The back portion 30 of the second sub-frame telescopes in a direction G into the upstanding leg of the base portion 28. Handles 31 are provided protruding rearwardlyfrom back portion 30.
The leg portion 42 of the second sub-frame is also telescopically fitted in direction D onto the otherfree ends of the base portion 28 of the second sub-frame.
Footrests 44 are of cast aluminium and are of the usual type provided on wheelchairs, that is they are pivotal about a horizontal axis.
Arm rest 34 slides in direction A into retainer slots 36. Remote control 35 may be fitted onto either the right or left hand arm rest 34 depending on a preference of the disabled person.
Retaining member 40 in the form of a strong piece of spring steel is provided to fit within recess 21 of the first module. Latch members 38 cooperate withlocking bar 26 in a manner to be described hereinbelow.
Referring to Figure 4 the remote control module 35 comprises a main housing 71 which carries a joy stick 72. Indicator light 73 indicates the degree of charge in the battery. On/off switch 74 operates the control mechanism. Horn button 77 operates thehorn. Arm 75 is provided to fit the remote control onto the arm 34 of the wheelchair by sliding it indirection C. Cord 76 leads to the battery and controlbox. Control box 50 is illustrated in Figure 5. Cord 76ends in a plug 78 into control box 50. A circuitbreaker 80 is provided on the top of the control box50. The circuit breaker can be reset on overload andprotects the motor against damage from reversing the polarity. Plug 82 is a key and a battery charger.
Facia 79 fits onto the front of the control box 50.
The hand brake is illustrated in Figures 6 and 7. It comprises a knob 84 mounted on the top of lever 86.
Lever 86 drives link 88 which in turn is pivotallymounted on brake plate 90.
Base plate 87 is provided for mounting the handbrake at a suitable position on one of the modules so that the brake plate 90 can be applied against one of the wheels.
Returning to Figure 1 when the wheelchair is to beassembled handle 27 is rotated to be in a verticallyupright position. Recesses in bar 26 which aresemi-circular in section corresponding to recesses24 in members 23 are in registry with bores 22 inbackbone 18. Thus when male members 23 areinserted in the direction of arrow E into the bores 22insertion can continue until recesses 24 are in registry with locking bar 26. Locking bar 26 is then rotated through 90 clockwise which engages a non-recessed portion of bar 26 with recesses 24 locking the second module to the first module of the wheelchair. In a similar manner male members 23a of the first and second alternatives of the second module can be interlocked with the first module main frame.
Slot 60 of longitudinal frame member 58 is engaged over a bolt extending inwardly in the downwardly extending portion of side frame 20.
When the bolt is tightened into a threaded bore in side members 20 and onto this slot torsional motion of frame member 58 is substantially prevented.
The third module is interlocked with the first module by inserting retaining member 40 into slot 21 in the backbone 18 of the main frame. The main frame is then lowered in the direction of arrow B and the flat recessed portions of locking bar 26 are aligned vertically upwardly so that the narrow portions of the catches 38 pass over them. Handle 27 is then rotated through a further 90 in a clockwise direction to be in the locking position illustrated inFigure 1.
Arm rest 34 is adjustable by pushing outwardly. A dowel extending outwardly within retainer 36 is disengaged from the slots illustrated allowing up or down movement of the arm rest.
Similarly the height of the back portion 30 can be adjusted by telescoping the frame upward or downward as desired so that hand grips 31 are at a suitable height.
The joy stick 72 is of a conventional electronic type and the arrangement being such that the further it is pushed forward the more quickly the motor runs in a forward direction and vice-versa.
Indicator light 73 glows green when the battery is at full charge, flickers red when the charge is running low and is a continuous red when the charge is so low the chair will no longer be operable.
The hand brake illustrated in Figures 6 and 7 is operated by pushing the knob 84 from right to left (referring to Figure 7) to thereby push brake plate 90 against a rotating wheel adjacent to it.
In the first alternative of the invention illustrated inFigure 2 the second module consists in a spoked wheel 70 having a hand rim (not illustrated) for manual propulsion of the wheelchair. The stub axle of the wheel is fitted into upper bearing 62 in longitudinal frame 58. In this alternative the wheelchair has its highest and most rearward centre of gravity.
In the embodiment illustrated in Figure 2 the second alternative, wheel 68 is mounted on a stub axle in lower bearing 64 of longitudinal frame member 58. In this embodiment the centre of gravity is lower and more forward as compared to that illustrated in Figure 2.
When the chair is assembled in the second alternative, foot pedals 66 may be used by an attendant to the wheelchair to tilt up the front of a chairfor mounting curbs and other obstacles.
The third alternative mode is that illustrated inFigure 1 wherein the second module is the electric drive discussed hereinabove. In this third alternative the centre of gravity is still more forward and lower than that of the embodiment illustrated in Figure 3.