CA1213511A - Wheel chair for handicapped persons - Google Patents

Abstract

ABSTRACT
A wheelchair for handicapped persons with a seat disposed on a movable frame, a battery set for the power supply of drive motors coordinated to the wheels of the wheelchair and a steering system for controlling the stop of the wheel groups for the purpose that the wheelchair can drive up and down stairs automatically, which is characterized in that the movable frame comprises two frames disposed on top of each other, which carry a compressed air container with coordinated compressor and where vertically standing double acting piston cylinder units hinged at the longitudinal side pieces for the vertical adjustment of eight wheelchair wheels combined to four wheel groups, such that the frames with the piston cylinder units are adjustable relative to their side projection like a parallelogram, that the seat is hinged at the upper frame, and where a stabilization system is coordinated to the seat under maintaining of its horizontal position at different relative positions of the upper and lower frames.

Description

WHEEL CHAIR FOR HANDICAPPED PERSONS

The invention relates to a wheelchair adap-ted Eor climbing and descending stairs by utilizing a pneuma-tic system.

It is an object of -the invention to provide a wheelchair for handicapped persons such that the person sit-ting in the wheelchair is in principle in the posi-tion to drive down and up stairs with this wheelchair without the aid of a further person, where an auxiliary person or an accompanying person would possibly only have the job to exert a safeguarding function for psychological reasons against a too rapid crossing of the individual steps.

This object is achieved by means of a wheelchair compris-ing a frame comprising an upper sub-frame adjustably linked to a lower sub-frame, a seat adjustably mounted to the frame, groups of wheels supporting the frame, and electric drive means drivingly connected to the groups of wheels for displacing the wheelchair in a horizontal direction. The wheelchair also comprises a first pneumatic drive system connected to the groups of wheels for select-ively displacing the wheels vertically, a second pneumatic drive system connected to the frame and to the seat for adjusting -the position of the seat relative -to the frame, detection means connected to the groups of wheels for

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detecting -the presence of a vertical barrier and the absence of a horizontal support for each group of wheels, and a control unit for actuating the first and second pneumatic drive system to selectively raise or lower groups of wheels while simultaneously adjusting the position of the seat relative to the frame so as to maintain the seat in a horizontal position. By means of this invention, a wheelchair is thus provided which is adapted to climb or descend stairs while maintaining the seat in a horizontal position.

The possibility exists with such a wheelchair that for...

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example the wheel ~roup, which encounters a vertical hindrance presant as the edge of a stair step, is lifted up into the region of the flat surface of the step such that the wheelchair can move again in the direction of the stair. Upon each successive hitting by a wheel group against the edge of a step the corresponding wheel groups are lifted up, where an inclined position of the two frames of the motion frame results. With reference to the individual wheel groups of the wheelchair there results an endless track type of movement up along the stair. The stabilization system coordinated to the seat assures that the seat maintains its horizontal position even in case of different relative positions between the upper and the lower frame.

Safety, control and handling provisions are coordinated to the wheelchair in accordance with further embodiments of the invention, as they are described in the subclaims.

In the following, the invention is illustrated in more detail by way of the drawing.
It is shown in:
Fig. 1 a schematic representation of a side view of a wheelchair standiny on a planar surface;

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Fig. 2 a rear view of the wheelchair on a planar surface;
Fig. 3 a plan view onto the wheelchair;
Fig. 4 a schematic representation of a side view of the wheelchair standing on several steps of a stair;
Fig. 5 and 6 in each case show details of the wheel support in an exploded view;
Fig. 7 ls a sectiona] view of a pressure switch for the safeguarding of the wheels against unintended adjustment in vertical direction.

The drawings show the various views of a schematically represented wheelchair for handicapped persons. The frame of this wheelchair cornprises two frames 1 and 2 disposed on top of each other, in particular constructed from rectangular tube. The lower frame 1 comprises two longitudinal braces 3 and 4 running parallel in driving direction of the wheelchair and two parallel disposed cross braces 5 and 6, which form a midd]e rectangular frame part at a distance from the ends of the longitudinal braces 3 and 4 and are attached to the longitudinal braces. Preferably, the upper frame has the same shape as the lower frarne, that is the upper ~rame comprises two longitudirla]ly running braces 7 and 8, which are connectecl to each other by cross braces 9

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and 10. The shape of the upper frame 2 and thereby also the shape of the lower frame result in particular from Fig. 3.

Cylinders 11a to 11h of double acting piston cylinder units are hinged to the two frarnes 1 and 2 over the length of the longitudir)al braces dlstributed on the two sides of the frarnes 1 and 2, such that the frarnes 1 and 2 together with the cylinders in the side projection forrn a parallelogram lin~age, 7;he movability of which results as shown substantially in the Figs. 1 and ll (horizontal starting position on the one hand and sloped position on the other hand) The cylinders 11a to 11h or, respectively, the corresponding piston cylinder units serve to provide the vertical adjustment of pneumatic wheels 12a to 12h, the support of which is described further below.

Pneurnatic cylinders 13 or, respectively, 14 are hinged in each case between longitudir7al braces 3 ancl 7 disposed on top of each other ancd 4 and ~ on the other side, which serve t;o stabilize or, respectively, fix in each case the relative position between the upper and the lower f`ranle.

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A seat 17 is tiltably disposed at the upper frame 2 by way of two bearing blocks 15, 16 attached to longitudinal braces 7 or, respectively, 8. Hand].ebars 18 or, respectively, 19 disposed at the two longitudinal sides of the :Eranle serve to stabi].ize the seat 17 arld the handlebars are on the one hand attached to the lower frarne l and on the other hand to bottorn side of the seat 17. The length of the handlebars 18, 19 as well as the position of the upper and of the lower hinge points are adjusted relative to each other such that independent frorn the position of the two -~rames 1 and 2 in each case the same relative position of the seat is assured relative to a horizontal reference plane, as can be gathered from Figs. 1 and 4. Also other units, preferably in the shape of pneurnatic cylinders can be provided for the stabilization of the seat in its horizontal position. The seat 17 essentially cornprises a rectangular ~rarne 20, where~
foot supports 22 are attached via a linkage 21, as well as a seat shell 23.

A dri.ve switch not showrl and a steering provision not shown are mounted to the seat l7.
Basic :further cornponerlts o:f the invent;iorl wheelchair are a set of batteries 24 rotatably attached to the upper frame 2, a compressed air container 25 rigidly mounted at the lower frame 1 with coordinated compressor 26 and a steer-ing system not shown in detail for controlling the fold-ing of the individual wheel groups.

The compressed air container 25 fed with compressed air from the compressor 26 is connected on the one hand to the cylinders lla to llh as well as on the other hand to the pneumatic cylinders 13 and 14 via lines not shown here.
A level control provision 27 is attached to the rear side of the seat 17 associated with a corresponding control device and serves to maintain the preset relative position of the seat 17 relative to the horizontal reference plane and for controlling the supplying of the individual cylinder units lla to llh and 13, 14 with compressed air.

Parallel aligned contact bows 28a to 28h movable in horizontal direction are coordinated to the wheels form-ing in each case a group of wheels. The contact bows 28a to 28h are provided on the one hand with lower bottom contacts 29a to 29h and they can on the other hand actuate side contacts no-t shown by way of a horizontal shi~ting.

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An elec.cric drive motor 30a to 30h is coordinated to each wheel 12a to 12h. The drive motors are connected to the battery set 24 by way o:f ].ines not shown here.

The sequence of operational. functioning of the inventi.on wheelchair for driving up ascending stairs is as fol.lows: The drive motors 30a to 30h cirive the wheels 12a to 12h at low speed in backward direction. If the contact bows 29d, 29h of the rear wheel pair 12d, 12h push against the first step riser I and are adjusted in a horizontal direction and thereby actuate the side contacts, rnicroprocessors of all wheel sets integrated into the level control provision and the control device 27 are actuated in order to stop all drive motors 30a to 30h and to supply on the other hand all other cylinders 11a to 11e with the exception of the cylinders 11d, l1h with compressed air, such that the coordinated pistons and thereby the wheels 12a to 12g are driven downward, whereby the wheel set corrlpri.sing the wheels 12d and 12h is lifted ~p together wi.th the frames 1 and 2 ~ntil the coordinated contact bows 2~d and 2~h are released, that i.s they do not any longer contact the step riser I.

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New control orders are released within the apparatus 27 based on the thus achieved release of the contact bows 28dJ
28h in such a way chat all drive rnotors 30a to 30h are driven agairl in reverse gear.

Upon each successive contacting of a contact bow pair against one of the step risers I, II, III, or ~I Or a staircase the same or cornparable operations repeat in the way that on the one hand the drive motors 30a to 30h are stopped and that on the other hand certain wheel sets are rnoved in or out such that in each case the wheel set contacting with its contact bows against one of the step risers is adjusted relative to the other wheel sets. Thereby at the same time an inclined position of the two frames 1 and 2 results, where control orders ~rom the control device 27 on the one har1d are transrnitted to the cylinders 12a to 12h and on the other hand to the pneumatic cylinders 13 and 14, in order to control the corresponding inclined slope of the two f`rarnes 1 and 2 depending on the state ofrnoving in or rnoving out of the individual wheel sets.

The individual wheels are hlocked against forward rnotion d~ring the upward motion of the wheel chair.

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The following functioning sequence results for the driving down a descending stair: The drive rrlotors 30a to 30h are driven ac a srnall speed in forward direction. I~ the front running wheels 12a, 12e leave the uppermost step surface VIa and irnMediately thereupon the coordlnated floor contacts 29a, 29e irnpact this step surface and are loaded thereby, then the pneurnatic cylinders 11a, 11e are blocked. Upon further rnotion the floor con'cacts 29a, 29e are again relieved with che consequence thac all drive motors are stopped. At the same time the cylinder units 11a, 11b are released and drive to the step sur~ace IIIa disposed below.
Then the drive motors 30a to 30h are put again into operation after a time delay controlled by microprocessors such that the wheels 12a to 12h are driven in forward direction. Upon each following release and reloading of the floor contacts the corresponding control orders are released with the provision that it is always assured that at least three wheel sets rernain in contact with the floor and on the other hand the inc]inecl position of the frarnes 1 and 2 is controlled depending on the height level taken by the individ~al whee:l set depending in turn on the downwarcl motion of the whee:Lchair in each case.

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In order to provide for the case of a sudden pressure drop in the compressed air system, a blocking system is provided in order to block all cylinders 11a to 11h as well as the pneurnatic cylirlders 13 and 14 in their position in each case.

The Figs. 5 ancd 6 show the support or, respectively, the suspension o~ the individual wheels including the piston cylinder uni.ts with hinged support at the longitudinal braces. The individual piston cylinder unit 11 comprises a cylinder 31, which is provided at its upper and lower ends with radially protruding thicker sections 32 or, respectively, 33. The axle journals 34 or, respectively~ 35 are attached at these thicker sections 32 ancl 33, which axle journals are preferably from a hollow stock in order to connect the upper and lower ends of the cylinder 31 to the compressed air container 25 by way of compressed air lines.

The two longitudinal braces ~ and 4 are provided wi.th bearing bores 36 :~or t;he receiv:irlg o:~ the axle journals 34 or, respectively, 35. The piston rod 3~ protrucl:i.ng ~rom the cyllnder 31 has a threaded sectiorl 39 at its lower end.

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A parallel guiding element 40 is slid onto the cylinder 31 between the radia].ly thicker sections 32 and 33, For this purpose at least one of the two thicker sections 32 or 33 is demountably attached to the cylinder 31. The parallel guiding element 40 comprises a first tube section 41 surrounding the cyli.nder 31 and the lower and upper trapezoidal stiffening plates 42 are rigidly connectecl to a second tube section 43 running parallel to the first tube section 41.

A steering strap 53 is attached on the side of the first tube section 41 of the parallel guiding element 40.

The second tube section 43 serves to provide the shiftable support in axial direction of the parallel guide tube 44 shown in Fig. 6, which is assured against a rotation relative to the second tube section 43. A cross bow 45 iS
attachecl in the region of the lower section of the parallel guide tube 44 and a bearing cheek 46 is attached to the cross bow 45, which beari.ng cheek 46 again runs in parallel to the parallel guide tub~ L~
The cross bow 45 is provided with a threaded bore 52 open toward the top and the threaded shaft 39 of the piston rod 38 is screwed into the threaded bore 52.
~eari.ng bushings 47 or, respectively, 48 for receiving the axis of a wheel 12 are tlisposed at the lower ends of both the parallel guide tube114 as well as of the bearing cheek 46. The cheek 46 is provided with a further support bore 49 f`or the attachrnent of a drive motor 30, wh.ich serves to drive the wheel 12 via usual drive elernents not shown here in detail.

A contact box 50 is attached at the lower end of the parallel guide tube IILI preferably in the region of the bearing bushlng 47, which serves a contact bow 28 with horizontally disposed guide bores 51. The contact bow 58 carries the floor contact 29 described above at its bottorn side. The contact bow 28 can be slid with regard to the contact box 50 in horizontal direction against an elastic pretensioning force in order to be able to actuate the side contacts disposed in the contact box 50 i.n the way described already above.

Upon supplying the piston cylirlder unit 11 wi.th corllpressed air the piston rod 38 is e:ither moved inward or outward, whereby a correspondingly directed force is transferred onto the cross bow attached at the parallel gulde tube 44. The parallel guide tube 44 ls thereby adjusted in vertical direction wichin the second tube section 43 and thereby also the wheel 12 supported between the lower end of the parallel guide tube L14 and the bearing cheek 46.

A pressure switch 54 is coordinated to the second tube section 43 and thus to the parallel gulde tube 44 (compare Figs. 2, 5 and 7).

The pressure switch 54 attached on the side of the second tube section 43 ln the reglon of a wall openlng cornprises a cyllnder caslng 55, which shiftably supports a plunger 56.
This plunger 56 ls on the one side loaded with a spring 58, whlch exerts on the plunger 56 a force in such a dlrectlon that a pressure sta~Dp 59 dlsposed on the other side of the plunger, whlch is supported slldably ln an opening 61 of a cylinder cover 60, is moved out of the cyl.lnder to such an extent that lt is pressed against the parallel ~uide tube 44 through the above recited wall openi.ng of the second tube section L13 in the contact and bolting position. A compressed air line 62 joins the cylincler space of the cylinder 55 `` ~Z1~

disposed toward the cylinder cover 60, which pressure line 62 is also connected to the compressed air container 25. In order to adjust a wheel there is also required a supplying of compressed air to the plunger 56 of the coordinated pressure switch 54 in addition to the supplying of compressed air to the cyl inder 31 in each case. The supplying of compressed air to the plunger 56 allows to move the pressure piston 59 against the force of the spring 58 from the position moved into the second tube sec.tion Ll3 anà
bolting the parall.el guide tube 44. As soon as the parallel guide tube 4LI has reached again a final position, the supplying o:E compressed air to the plunger 56 is interrupted such that the pressure piston 59 is moved into its position locking the parallel guide tube under the influence of the force of the spring 58.

The pressure switch 54 thus fulfills the purpose to prevent uncontrol led vertical repositionings of the individual wheels in case of interferences in the compressed air system .

A steering systern or a steer:i.ng linkclge not shown engages the individua]. steering straps 53 of the parall.el guide ~35~g~

elements 40 in a way not part of the invention. In order to set the trace of the indiviciual wheels, the individual parallel guiding element 40 is turned with its first tube section 41 arour~d the axis of the cylinder 11, which entails a corresponding tiltirlgrrlotion of the ,second t~be section 43. This tilti,ng nlotion is f'ol],owed by the parallel gruide tube 44 secured within the second tube section against rotation, which results in a correspondin~, change o:f the course or, respectively, steering position of the individual wheel 12.

Claims (13)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A wheelchair adapted for climbing and descending stairs, comprising a frame, said frame comprising an upper subframe adjustably linked to a lower subframe, a seat adjustably mounted to said frame, groups of wheels supporting said frame, electric drive means drivingly connected to said groups of wheels for displacing said wheelchair in a horizontal direction, first pneumatic drive means connected to said groups of wheels for selectively displacing said groups of wheels vertically, second pneumatic drive means connected to said frame and to said seat for adjusting the position of said seat relative to said frame, detection means connected to said groups of wheels for detecting the presence of a vertical barrier and the absence of a horizontal support for each group of wheels and for generating signals in response thereto, and control means for generating signals to actuate said first and second pneumatic drive means to selectively raise or lower groups of wheels and to simultaneously adjust the position of said seat relative to said frame so as to maintain said seat in a horizontal position in response to signals received from said detection means, whereby said wheelchair is adapted to climb or descend stairs while said seat is maintained in a horizontal position.

2. The wheelchair of claim 1 wherein said upper subframe is parallel to said lower subframe.

3. The wheelchair of claim 1 wherein said upper subframe and said lower subframe assume a parallelogram linkage when said wheelchair is climbing or descending stairs.

4. The wheelchair of claim 1 wherein each of said groups of wheels is perpendicular to the plane of the ground when said wheelchair is climbing or descending stairs.

5. The wheelchair of claim 1 wherein each of said groups of wheels has a separate electric drive means associated with it.

6. The wheelchair of claim 1 wherein said control means further controls operation of said electric drive means.

7. The wheelchair of claim 1 wherein said seat is hinged to said upper subframe.

8. The wheelchair of claim 1 further comprising side handlebars hinged to said lower subframe and to said seat.

9. The wheelchair of claim 1 wherein said electric drive means is powered by batteries mounted to said frame.

10. The wheelchair of claim 1 wherein said control means includes at least one microprocessor.

11. The wheelchair of claim 1 wherein said first and second pneumatic drive means are air driven.

12. The wheelchair of claim 1 wherein said detection means are mechanical detection means.

13. The wheelchair of claim 1 comprising four groups of wheel pairs.