US 3196970 A
Abstract available in
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Description (OCR text may contain errors)
D. E. BRENNER STAIR-CLIMBING WHEEL CHAIR 3 Sheets-Sh 1 Filed May 17 1963 0,44:- f. BRf/VMSE July 27, 1965 D. E. BRENNER STAIR-CLIMBING WHEEL CHAIR 5 Sheets-Sheet 2 Filed May 17, 1963 INVENTOR. But f. Exam/v52 July 27, 1965 D. E. BRENNER 3,196,970
STAIR-CLIMBING WHEEL CHAIR Filed May 17, 1963 s Sheets-Sheet s j BY Armqwe'f United States Patent SsALhLEMBlNG Cilr'lLi Dale Brenner, 2912 Fine View Drive, York, Fa. Filed May 17, 19%, Ser. No. 231,163 lit Qlairns. El. 1342-3) This invention pertains to a stair-climbing wheel chair, and, more particularly, to a chair of this type capable of being adjusted to ascend and descend Stairways of differ ent tread widths and heights.
Conventional invalid chairs have been used for many years and are well suited for transportation of invalids over horizontal surfaces, such as floors. in somewhat recent years, various attempts have been made to devise wheel chairs capable of ascending and descending stairs, particularly with reasonable safety, and especially through the utilization of a minimum amount of either physical or motive energy. Certain of these prior attempts have been quite complex and, accordingly, costly to produce. l-Iotwithstanding this, however, it must be recognized that there are relatively wide variations in the widtns and heights of stair treads in ditferent homes and buildings, whereby an invalid wheel chair capable of climbing stairs of one size would not be adapted to climb stairs of a different size, i.e., the heights and widths of stair treads in one dwelli or building, as distinguished from those another, it being understood that in each instance, all of the stair treads of a particular or given stair will have the same width and height.
it is the principal object of the present invention to provide a wheel chair capable of climbing stairs and including propelling means which are adjustable to render the chair capable of climbing stairs having treads of different heights and widths than those of other stairs, within reasonable limits, thereby renderina the chair substantially universal for use in climbing stairs.
Another object of the invention is to provide the aforementioned chair with wheel means to be used in normal, horizontal movement of the chair when not climbing stairs, said wheel means being mounted so as to be rendered inoperable when the propelling means which permit the chair to climb stairs are rendered operative.
Still a further object of the invention is to include means in the above-described chair by which the same may be colla ed, at least to a limited extent, transversely, thereby rendering the chair capable of being stored in a small r space than otherwise would be possible, and also of enabling the chair to be readily placed within a motor vehicle for use by an invalid occupant of the vehicle when the destination is reached.
Still another object of the invention is to provide the aforementioned type of chair with power means to actuate the propelling means for use when the chair is adapted to climb stairs.
One further object of the invention is to provide a plurality of propelling units in the aforementioned type of chair which are spaced longitudinally of the frame of the chair, fore and aft of the center of gravity of the seat means or the chair, each unit having a plurality of stair tread engageable members, which, in their referred embodiment, are non-rotatable with respect to the engagement thereof with such stair treads.
Still another object of the invention ancillary to the immediate foregoins objects is to provide said units with spider-like members rotatable about horizontal axes and having shoe means pivotally connected with the outer ends of the arms of the spider-like means so as to be ported in pendent fashion therefrom, the width of t c shoes being suilicient to afford firm, fiat engagement of substantial areas with the stair treads.
Still another object of the invention, ancillary to the immediate foregoing object, is to provide connecting means between the spider-like means of said units and the shoes pivotally connected thereto so as to permit radial adjustment of the pivots of the shoes with respect to the pivots of the spider-like means, whereby said propelling means Comprising said units are adapted to stairs of reasonably different heights and widths of treads, as distinguished from those of other stairs.
Details of the foregoing objects and of the invention, as wel as other objects thereof, are set forth in the following speciiicat -n and illustrated in the accompanying drawings comprising a part thereof.
in the drawings:
PEG. 1 is an eXem-p ary side view of a stair-climbing chair embodying the principles of the present invention and illustrated in process of negotiating an exemplary set of stairs, the wheel means employed durin" horizontal movement of the chair over a floor surface being shown to inoperative position in said view.
2 is a side elevation showin the chair illustrated in FIG. 1 adapted to movement over a horizontal surface, such as a floor, while the stair-negotiating propelling are disposed in inoperative position;
F 3 is a front view of the chair arranged in the position shown in 2 part of the middle portion of the chair being broken away to foreshorten the view.
FIGS. 4 and 4a respectively are side and rear views of the seat means of the chair shown in the preceding View.
PEG. 5 is a top plan view of the chair shown in FIGS. 1 through 3 with the seat means removed therefrom so as better to illustrate details of the power means of the chair.
FIG. 6 is a fragmentary rear end view of the drive shaft which is energiz d by the power means shown in PEG. 5, the scale employed in EEG. 6 being larger than that used in PEG. 5.
FIGS. 7 and 8 respectively are side and end views of one of the side frame members or" the chair shown in FlGS. 1 through 3.
FIG. 9 is a fragmentary front view of the power pack illustrated on a larger scale than that of FIG. 5 and illustrating the power pack shown in the latter figure.
PEG. it) is a side elevation, partly in section, of the motor and gear reduction unit employed in the drive means shown in FIG. 5.
PEG. 11 is a rear View of a cross strut of the frame of the chair shown in FIG. 5 and by which the motor of the power unit is supported.
FIG. 12 is a fragmentary plan View of part or" the frai e by which the power pack is supported and illustrated in partially contracted condition.
FIG. 13 is a fragmentary perspective view of part of the frame mechanism illustrated in FiG. 12.
FIG. 14 is a face view of one of the spider means of a propelling unit and showing a preferred method of adjustably supporting stair-tread engageable shoes thereon.
FIG, 15 is an enlarged fragmentary side elevation of one extremity of an arm of the spider means of the propelling units and illustrating an exemplary shoe adjustably connected thereto.
FIG. 16 is a side edge view of the fragmentary mechanism illustrated in FIG. 15.
PEG. 17 is a fragmentary edge View of the bell crank by which the principal supporting wheels for the chair while transversing horizontal floor surfaces are moved between operative and inoperative position and maintained in such selected position.
FIG. 18 is a fragmentary enlarged view of the adjust able mounting means for the rear supporting wheels em- :plates in detail. and aft bearings 32- and 34 to receive bearing shafts for the propelling units 18 and 20. Said side plates, also, in the uppermost portion thereof, including an open ended bearing notch 36 within which trunnions on the seat unit means.
ployed when the chair is negotiating horizontal surfaces, as shown in FIG, 2.
FIGS. 22 and 19 respectively are edge views and face views illustrating a fragmentary portion of the extremity of a bell crank which supports the large Wheels employed in FIG. 2 for horizontal movement of the chair.
FIG. 20 is a fragmentary view of part of the frame by which an idler, belt-tensioning roller is adjustably supported for vertical movement.
FIG. 21 is a fragmentary view of the forward portion of the frame which supports the drive means for the forward propelling unit.
Referring to FIG. 1, there is illustrated a stair-climbing wheel chair which embodies the principles of the present invention and is illustrated in process of traversing a set of stairs 10. In this illustration, it is not important whether the wheel chair is ascending or descending the stairs because the only difference is, under such circumstances, that the power means is of a reversible nature and is controlled by the operator 12 for selective operation in either direction. When transversing the stairs 10, the chair and the operator are disposed in relationship to the stairs so that the operator faces downstairs, primarily because, in relation to the construction of the chair, it is more convenient to arrange the propelling means and other supporting means for the chair in such relationship to the seat of the chair that it is less complicated than if the seat and operator faced upstairs while traversing the stairs.
According to the preferred construction of the present invention, the chair embodying the principles of the present invention includes mechanism which is designated illustrated in stair-negotiating arrangement and in horizontal surface travel, said chair assembly basically comprises a frame 16, a pair of longitudinally spaced propelling units 18 and 20, a seat unit 22, and wheel means -comprising a pair of forward wheels 24 and, preferably,
a pair of rearwheels 26. The seat unit 22, selectively, may be either fixed in its position with respect to frame 16, or pivotally suspended from the upper portion thereof so as to permit the weight of the occupant or operator 12 to cause the seat to find its own position with respect to the frame through the operation of gravity.
As will be seen from FIGS. 1, 2 and 7, the frame 16 comprises a plurality of similarly shaped side plates 28 and 30, it being understood these respectively are mirror images of each other. In side view, the frame 16 may be considered somewhat to be A-shaped, as is evident particularly from FIG. 7 which shows one of the side Each of said side plates comprise fore 22 are received so as to provide support for said seat Further, intermediately of the confines of each side plate is still another bearing hole 38 provided for purposes of supporting the forward wheels 24, as described in detail hereinafter.
The opposite side plates 28 and 3d of frame 16 are connected together by a plurality of transverse struts or connecting members, which are best illustrated in plan view in FIG. 5, wherein only a portion of the chair as sembly is shown, principally comprising the frame 16,
, the propelling units 18 and 2b, and the power mechanism 4 for actuating the propelling units. The transverse connecting means for the side plates comprises an articulated rear connector comprising a pair of interconnected plates 4%) and 42, which respectively are connected by bolts, at the opposite ends thereof, to side plates 23 and 30, as clearly shown in FIG. 5. The opposite ends of plates 49 and 42 are connected together by bolt and Wing nuts .4, the bolt extending through appropriate hole in plates 42, for example, and plate 46' having longitudinal slots 46 therein, which likewise receive the bolts referred to and, when the nuts 44 are loosened, the plates 40 and 42 may be adjusted longitudinally with respect to each other to a limited extent, particularly for purposes of permitting theframe 16 of the chair to be contracted transversely to a limited degree for purposes of facilitating more compact storage and transportation of the chair when not in use.
A forward transverse strut also is articulated, especially for purposes of facilitating the contraction of the frame of the chair referred to above, said strut comprising a plurality of Z-shaped brackets 48, each of which have one end flange fixedly connected respectively to the frame plates 28 and 3%, as best illustrated in FIGS. 5 and 12. The opposite ends of the brackets 48 are pivotally connected to hinge members 5t and 52, said hinge members also being connected together. However, the latter also may be maintained in transverse position with respect to the frame 16, Within a common plane, by means of a latch member 54, see FIG. 5. Hinge member 50 also is provided with a boss 56 from which a mounting stud 58 projects upwardly to pivotally support a power pack 69, for purposes to be described hereinafter.
Also extending between the opposite side plates 28 and 3th of the frame, intermediately of the front and rear transverse strut means, is a longitudinally contractible drive shaft 62, comprising, for example, complementary elongated socket and shaft members which are axially slidable,but are non-rotatable relative to each other, the opposite ends of the drive shaft 62 being supported within bearings 34 within the side plates 28 and 30, as shown in detail in FIG. 6. The details of the articulated shaft 62 by which longitudinal expansion and contraction may take place also is illustrated to advantage in FIG. 6. Further, from said figure, it will be seen that a gear housing 64, which contains reduction gearing specifically illustrated as a worm gear 66 and worm 68, as shown in FIG.
6, is associated with power shaft 62, the worm gear 66 being keyed theretoin conventional manner, and said shaft also extending through suitable bearings in opposite sides of the gead housing 64, likewise in accordance with conventional construction.
Worm 68 is driven by drive shaft 70 of motor 72. A
motor-supporting bracket '74, best shown in FIGS. 5 and 10, is fixed by suitable bolts, or the like, to plate 42 of the rear strut means. A suitable electrical conductor 76 extends between power pack 6%? and motor 72, as well as similarly extending to a control switch 78, shown in FIG. 1, as being mounted conveniently for operation by the hand of the occupant 12. Such electrical conductor prefer-ably is flexible and also is provided with plug and socket connector means to permit ready connecting and disconnecting of the conductor, when desired.
Particularly from FIG. 5, it will be seen that when the wing nuts 44 on the rear strut means and latch 54- on the forward strut means are loosened and disconnected respectively, said transverse strut means may be contracted a limited extent, as can the articulated, telescopically arranged drive shafts 62, thereby permitting movement of frame plates 28 and 36 toward each other a substantial amount. Such contracting is made possible particularly due to the pivotally arranged support for the power pack about the axis of the mounting stud 58, the collapsing of the forward strut, at least to a partial degree, being illustrated in exemplary manner in FIG. 12. When so contracted or collapsed, the frame 16 readily may be stored in more compact space, or placed within a motor vehicle in a smaller space than otherwise would be possible if the frame could not be collapsed or contracted.
Frame 16 supports the propelling units it; and as, which respectively comprise transversely spaced pairs of spiders 8% one of which is shown in detail in FIG. 14. In the preferred embodiment, each spider is provided with four arms of equal length and spaced even circumferentially. The outer end of each arm is provided with a series of intersecting holes 82, which comprise means permitting longitudinal adjustment of the arms, in a radial direction with respect to the axis of each spider, whereby stair tread-engaging pads or feet 34 may be respectively connected to the outer end of each arm of each spider. It is to be understood, incidentally, that the above-described specific means for affording longitudinal adjustment of the feet 84 with respect to the outer end of one arm of each spider is merely exemplary and cornprises a relatively inexpensive means for accomplismng such adjustment simply by suitably positioning pivot bolts 8:: correspondingly within a selected hole of the groups of holes 32 in the outer end of each arm of each spider.
Each spider is provided with a hub 88, which is connected by means of a transverse key 99, or other suitable means, either to opposite end portions of the drive shaft 62, or to the inner ends of short drive shafts 92, see FIG. 21, which extend through bearings 32 in the forward portion of the side frame plates 23 and of frame 16. Also keyed to each of the short drive shafts 92, as well as to the opposite ends of the main drive shaft 62, are sprocket gears or pulleys 94, which are fixed by keys 95 respectively to the shafts which support said sprocket gears. Also supported within an elongated, vertically extending slot 98 in each frame plate 23 and 33, see FIG. 7, is an adjustable idler pulley or gear which is rotatable about a short shaft 1162, details of which are best shown in FIG. 20.
Extending around the sprocket gears or pulleys 9 which are pivotally supported respectively adjacent each of the side plates 23 and 3% of th frame, and also around the idler pulley or gear lid) on each frame, is a flexible sprocket chain or V-belt 1%. In view of the fact that main drive shaft 92 is driven by the motor 72-, which is energized by power pack as, the sprocket gears or pulleys 94, which are connected directly to main drive shaft 62, respectively will drive the sprocket chains or V-belts 1% connected thereto and, as a result, likewise drive the forward spocket gears or pulleys 94 which are connected to the short drive shafts $2 to which the spiders it of the forward propelling units 13 are connected. The spiders ill of the rearward propelling units 2%, which are connected directly to the main drive shaft 62, as shown in FIG. 6, will be directly driven by said main drive shaft. Hence, through the action of the sprocket chains or V- belts ill-l at opposite sides of the frame, which chains or belts preferably are maintained relatively taut through the idler tensioning gears or pulleys laid, it will be seen that precise orientation of the pads or shoes 84 in the forward and rearward propelling units is and 29 will be maintained, as will be described hereinafter in greater detail.
Supported preferably by the upper portions of each of the side plates 23 and 30 of frame 16, within the bearing notches 3% thereof, is a preferably skeleton-like and lightweight seat unit 22, details of which are best shown in FIGS. 4 and 4a. Said seat unit, in the preferred construction, comprises tubular, or other suitable types, of side frames 1%, each of said frames including arm plates 3E3. The upper ends of said side frames also extend rearwardly to provide hand grips lit? by which an attendant, if desired, may propel the occupant of the chair over a horizontal surface, such as a floor 112-, when the propelling units are immobilized and the forward and rearward wheels 24 and 2-6 are placed in operation, as will be described hereinafter.
. gage successive stair treads, as shown in FIG. 1.
Each of the side frames tee of the seat unit 22, beneath each arm plate 1%, for example, is provided with a trunnion 11d and, extending outward from the lower forward end of each side frame we of the seat unit 22 is a foot tread 115 which, if desired, may be pivotally connected to the lower end of each side frame so as to be capable of being folded to a more compact position.
As best seen from FIGS. 1 and 2, there is a flexible back member 116, made from canvas or the like, which extends between the rear uprig it portions of the side frames 1 36 of seat unit 22 and, also extending between the lower horizontal portions of side frames tee is a similar flexible seat member or panel 118. To maintain these back and seat members relatively taut, and also otherwise to rigidify the seat unit 22, collapsible transverse struts 12d and 122 provided, the location of these best being illustrated in Figs. 4 and 4a. It also wil be seen that portions of said struts are hingedly connected and maintained rigid by suitable latch members 3'24, which are shown in detail in FlG. 4a. Such arrangement enables the space side frames ass to be contracted toward each other, as when the side plates 28 and fill of the frame 16 likewise are being contracted so as to render the entire chair unit more compact for storage or transportation.
As best shov n in FIGS. 1 and 2, the seat unit 22 is supported by the trunnions 114, at opposite sides thereof, being disposed within the open bearing notches 36 in the upper portion of frame 16. By such arrangement, when the seat unit 22 is occupied by a person, said seat unit and occupant will find its own level and the design of the seat unit, particularly ith the position of the trunnions 31dthereon, is such that when the chair assembly is negotiating stairs, as shown in FIG. 1, the center of gravity of the seat unit and occupant is disposed between the effective feet of the longitudinally spaced propelling units it? and if desired, suitable latch means, not shown, may be provided between frame 16 and the seat unit 22 so as to hold the seat unit against pivotal movement about the axes of its trunnions 114, if desired, especially when the chair is negotiating a horizontal surface, such as shown in FIG. 2, when the wheels 24 and as are employed in lieu f the propelling units 18 and 2t).
When the chair assembly is negotiating a flight of stairs it), either in ascending or descending movement, it can be seen that, at four times during each revolution of the spiders 36 of each of the forward and rearward propelling units, two of the pads or feet 84 on each spider will en- This situation only occurs momentarily, however, and, immediately thereafter, only one foot 84 on each spider will engage a stair tread, but, even under such circumstances, transverse pairs of such feet 84 will engage the same stair tread. Accordingly, at no time will less than four of the feet 34, arranged substantially in a square, in plan view, he in contact with longitudinally spaced stair treads between which the center of gravity of the occupant of the chair will be disposed so as to assure ample support and steady movement of the occupant either up or down the stairs.
To insure that the above-described re ationship of the pads or feet 34 with respect to the stair reads will occur, and assuming that all of the stair treads in any particular set of stairs are of equal width and the risers are of equal height, the effective length of each arm of each spider may be adjusted in view of the series of intersecting holes 82, for example, or other equivalent means, by which the required ef ective length of each arm of the spiders may be determined so as to insure substantially the same position of engagement between each of the feet 34- and the succesive stair treads of any given set of stairs. Such effective length of the arms of the spiders 8d normally would be determined at the time the chair is new, for example, and is being adapted to a specific set of stairs, or, in the event the chair is taken to a new location where the width of the treads or height of the risers of the stairs is different from that for which the setting previously has been arranged, then a readjustment of the feet with respect to the spiders will be required. Unless some suitable form of adjustment is provided, however, it readily can be seen that any fixed relationship in regard to the effective length of the spider arms would enable the chair to be used only on one particular stair arrangement for which that given effective length of the spider arms is adapted for use.
While it is conceivable that the motor 72 can be oper ated at such speeds that ascent and descent of a set of stairs can be accomplished in a relatively short space of time, it nevertheless is preferred, particularly for purposes of conserving current of any given power pack 6%, that 'the propelling units 13 and 20 be utilized only for purposes of negotiating stairs. When the chair is to be used on a horizontal surface, such as floor 112, the chair is arranged so that a pair of so-called conventional forward wheels 24 may be lowered from the inoperative position thereof, shown in FIG. 1, to the operative position, shown in FIG. 2. Similarly, the pair of so-called conventional rear wheels 26 may be lowered from the inoperative position shown in FIG. 1, in which they also are clearly out of contact with any of the stairs, to the operative position thereof shown in PEG. 2.
When the wheels 24 and 26 are so lowered to their operative position, as illustrated in FIG. 2, it will be seen that the feet 84 of the propelling units 18 and 29 are at least slightly spaced above the floor surface 112, whereby they will not contact the same. Further, especially as is clearly evident from FIG. 5, the pads or feet 34 preferably are relatively narrow in a transverse direction, thereby affording rather ample space between the inner edges thereof and providing ready means by which a person who is to occupy the chair may approach the seat of the same, or be carried, so as to be disposed within said seat. It also is mentioned that, for purposes of simplification, FIG. does not illustrate the wheels 24 and 26, or the mounting means therefor; nor does it illustrate the seat unit 22.
The forward wheels 24, which are of substantial diameter and of the normal wheel-chair type having manual propelling means, are individually rotatably supported upon a short shaft 126 extending transversely from one end of a bell crank 123. One bell crank is connected to rounds the shaft and exerts pressure in a direction to hold the bearing sleeves 142 against the bosses 145.
When the chair is disposed in the position shown in FIG. 2, whereby the rear wheels 25 are in operative position, they are maintained in such position by means of any suitable indexing means, such as a pin 150, which preferably is fixed to boss 146, while the outer end thereof is receivable within a complementary hole 152 provided in each bearing sleeve 142. The springs 148 will serve to maintain the pins 15% within the holes 152.
Preferably, the sleeves 142 each are provided with a second hole 154-, see FIGS. 7 and 18, which also is capable of receiving the outer end of indexing pin 15%? when the spring 143 is compressed and the bearing sleeve 142 is revolved about the axis of shaft 144, through manipulation of suitable handle 156, until the bearing sleeves 142 and the wheel assemblies carried thereby are disposed in the position shown in FIG. 1, which is the inoperative position of the rear wheels 26. When this position is reached, each of said rear wheels will be maintained in such position by engagement of the pins 150 within the second holes 154 of the bearing sleeves 142, and the springs 145 will maintain such engagement of the pins and holes. It also will be seen that the handles 156 are positioned for relatively easy engagement by the hands of the occupant of the chair for manipulation between operative and inoperative positions.
While the invention has been described and illustrated in its several preferred embodiments and has included certain details, it should be understood that the invention is not to be limited to the precise details herein illustrated and described, since the same may be carried out in other said frame fore and aft of the center of gravity of said each of the side plates 28 and 30 of frame 16, intermediately of its ends, upon a short pivot 136, one of which is shown in FIG. 17. Preferably, the opposite arm or end of each bell crank 128 is relatively long and terminates in a handle 132, which, conveniently, is engage able by the occupant of the wheel chair so that he may manipulate the wheels 24 between operative and inoperative positions. bell cranks preferably is somewhat flexible, thereby permitting the outer ends of said longer arms of the bell crank to move a limited extent laterally outwardly fromoperative position, as shown in FIG. 2, whereas when the longer arms of the bell cranks 128 are snapped rearwardly behind the uppermost lugs 136, as shown in FIG. 1, the wheels 24 will be maintained, against the action of gravity, in the inoperative positions thereof.
The rear wheels 26 preferably are mounted in yokes 138 having vertical shafts 145), which are swiveled within bearing sleeves 142 provided with short supporting shafts 144 extending laterally therefrom and projecting through bosses or pads 146 provided on the rear, lower corners of side plates 28 and 31), as best shown in FIGS. 5, 7, 8 and 18. Preferably, the outer end of each supporting shaft 144 is headed and a compression spring 143 sur- Further, said longer arm of each of the seat means thereon, a plurality of stair step-enageable members pivotally supported in pendant manner by said propelling means and having flat surfaces engageable with the treads of spaced stair steps, means adjustably connecting said members to said propelling means to adapt said members for engagement with stair trends of different heights and widths, and means to actuate said propelling means and members supported thereby.
2. The stair-climbing wheel chair according to claim 1 in which the center of gravity of said seat means when occupied by a person will shift between forward and rearward positions relative to said frame by pivotal movement of said seat means about the apex of said frame while remaining between the forward and rearward ends of said frame.
3. The stair-climbing wheel chair set forth in claim 1 further characterized by said units comprising pairs of transversely spaced spider members and said stepengageable members are feet members having flat sur faces normally extending lowermost and horizontal and engageable with stair treads successively.
4. The stair-climbing wheel chair set forth in claim 3 further characterized by said spider members being supl ported by said frame for rotation about axes extending transversely of said frame and each member comprising a plurality of radially extending arms, and means pivotally connecting said feet members to said arms of said spider. members, the pivot means for said feet members amass o fore and aft of the center of gravity of said frame and all of said wheel means being supported by said frame for movement between lowered operative position for engagement with a floor surface and raised inoperative position out of engagement with such floor surface, said wheel means when in lowered operative position elevating said frame and stair step-engageable members above the lower portions or" said wheel means to prevent engagement of said step-engageable members with such floor surface.
6. A stair-climbing wheel chair comprising in combination, a frame substantially A-sliaped in side elevation, seat means supported by the apex of said frame for pivotal movement between two operative positions, propelling means supported by the lower portion of said frame and movable relative to said frame and comprising a plurality of spider units spaced fore and aft of the center of gravity of said seat means when in stair-climbing position, a plurality of members respectively pivotally supported by the arms of said spider units and having flat feet members successively en ageable with spaced treads of steps when climbing or descending the same, means to actuate said units to propel said chair up and down Stairways, forward wheel means supported by said frame intermediately of said spider units and rear wheel means supported rear wardly of said units, means supporting said forward and rearward wheel means for movement between lowered operative position for engagement with a floor surface and raised inoperative position out of engagement with such floor surface, said wheel means when in lower operative position elevating said frame and stair step-engageable members to prevent engagement of said me. bars on said units with such floor surface.
7. The stair-climbing wheel chair set forth in claim 6 further including manually operable means interconnected to said wheel means and arranged to move said wheel means between operative and inoperative positions.
' 8. The stair-climbing wheel chair set forth in claim 7 1Q further characterized by said manually operable eing handles movable relative to position-maintaining nernbers to hold the selected positions of said handles.
The stair-climbing chair according to claim 6 in which said means supporting said forward wheel means comprises a bellcrank pivotaily supported by opposite sides of said A-shaped frame, one leg of each bellcrank having bearing means supporting said wheel means and the other leg of each bellcranlr extending upwardly from the pivots of said bellcranlrs and comprising handles readily engsgeable by an occupant of said chair to raise and lower said forward wheel means between elevated inoperative position and floor engageable positions.
It The stair-climbing chair according to claim 9 further including position-maintaining means on said frame engageable by said handle legs of said bellcranks and operable respectively to maintain said bellcranlrs in position to maintain said forward Wheel means in said operative and inoperative positions.
References Cited by the Examiner UNETED STATES PATENTS 1,263,726 4/18 Altgelt -8 1,551,127 8/25 Whyel 288-5 2,460,824 4/46 Jackson 186-8 2,736,564 2/56 Loam et al 280-526 2,798,565 7/57 Rosenth-al et a1. 180-65 2,931,449 4/60 King 188-8 3,127,188 3/64 Greub 280-522 3,133,742 5/64 Richison et a1. 289-528 3,142,351 7/64 Green 189-8 FOREIGN PATENTS 187,291 7/07 Germany.
B. HERSH, Primary Examiner.
LEO FRIAGLIA, Examiner.