US3411598A - Stairclimbing wheelchair - Google Patents

Description

N 19. 1968 R. J. WEAVER 3,411,598

STAIRCLIMBING WHEELCHAIR Filed April 29, 1966 7 Sheets-Sheet 1 INVENTOR.

' RUFUS .1 WEA VER FIG. 1 BY 5 R. .1. WEAVER STAIRCLIMBING WHEELCHAIR 7 Sheets-Sheet 2 Filed April 29. 1965.

IIIICIIjEEEEE [NI/ENT'OR 1 RUFUS .z 'W'Al ER er I ATTORNEY Nov. 19,1968

R. J. WEAVER STAIRCLIMBING WHEELCHAIR Filed April 29, 1966 7 Sheets-Sheet 5 qMZ5O 1" I lllllllllllm Fig 354 54 rlla | IIIIIIII Innm v In llllflm FIG. /2a' INVENTOR RUFUS 4 WEAVER @KQYWMX A TTO/ZNEK Nov. 19, 1968 R. J. WEAVER 3,411,598

STAIRCLIMBING WHEELCHAIR 7 Sheets-Sheet 4 Filed April 29, 1966 FIG. 4'

78 FIG. 9

INVENTOR RUFUS J. WEAVER ATT ORA/Er;

Nov. 19, 1968 Filed April 29, 1966 R. J. WEAVER STAIRCLIMBING WHEELCHAIR 2 68 aee FIGS 7 Sheets-Sheet 5 INVENTOR RUFUS J WEAVER AT R/VEY 1963 i R. J. WEAVER 3,411,598

STAIRCLIMBING WHEELCHAIR Filed April 29, 1966 7 Shets-Sheet e INVE N TOR RUFUS J. WEA VER @LFM/W A T'TORJVE' V Nov. 19, 1968 R. .1. WEAVER 3,411,598

STAIRCLIMBING WHEELCHAIR I Filed April 29, 1966 7 Sheets-Sheet 7 FIG.

INVENTOR By RUFUS .1 'WEAVER v. ATTORNEY United States Patent 3,411,598 STAIRCLIMBING WHEELCHAIR Rufus J. Weaver, 14 East St., New London, Conn.

Filed Apr. 29, 1966, Ser. No. 546,242 16 Claims. (Cl. 1808) ABSTRACT OF THE DISCLOSURE My invention relates to a stair-climbing mechanism useful to mount a staircase automatically with a selfpropelling drive up the staircase and, in reverse, down the staircase usually carrying a load and is particularly useful in combination with ambulatory means, typically a wheeled vehicle such as a wheelchair which conveniently may be safely moved up and down a staircase and provide wheeled support and usual ambulatory movement to the stair-climbing means in horizontal motion.

In broadest aspect, the stair-climbing mechanism hereof is a combination of a stair frame element comprising rails disposed at opposite sides of the stair-climbing element, usually parallel to the sides, the stair-climbing rails most desirably being shaped as a continuous track shaped to conform alternately to risers and treads comprising the stair to he climbed, and in similar dimensions to coact with a standard staircase composed of risers and treads so that the rails will lie as parallel tracks upon at least a pair, typically three or more steps, of the staircase to be climbed, and movably support between them a driving mechanism. The driving mechanism preferably is encased in a housing having a bottom configuration also similarly sized and shaped to conform to treads and risers of the same staircase to be climbed while housing the driving mechanism.

The driving mechanism provides output rotary drive from upper and lower positions of opposite lateral sides and, for example, consists of two pair of crank arms and coupled to means for synchronously driving both pairs, with the outer crank pins each pivotally attached to a separate level such as an upper and lower stair rail, one at each side. In rotary movement, the four coupled crank arms rotate synchronously in a direction to climb the staircase, first raises the box housed driving assembly from a position resting on the two or three steps of the staircase supported between stationary held lateral resting rails as a stationary support on each side of the box, and continuous counter-clockwise rotation of the crank arms will lift the box-like climbing mechanism vertically and to the rear, rising upon its crank pins and carrying the housed driving assembly upward and to the rear to deposit it on the next higher step. From the 4 oclock position the boxlike climbing mechanism has its bottom contoured to meet the steps and disposed at the next step. At that point with the crank arms still rotating and with the housed body now resting stationary, the pins will then begin to lift the rails from the staircase both moving together at opposite sides of the housed drive, and carry them upward and to the rear to deposit the rails firmly upon the next higher step beside the housed box-like climbing mechanism. Thus, in continuous synchronous rotation of the crank arms, alternately raising the box from the rail to a next higher step and then raising the rail from the box, step by step, the climbing mechanism will climb the staircase. In reversal of the direction of rotation of the crank arms, the box-like mechanism will descend the staircase.

Patented Nov. 19, 1968 ice As the box approaches the top of the staircase, a prop arm is provided having a drive means to be automatically lowered to engage the level land area at the top of a staircase to support the highest step end of the box horizontally stable until the climbing mechanism is completely cleared of the staircase.

For preparing the mechanisms for alternate climbing or ambulatory use, at both upper and lower ends of the staircase, a mechanism means is provided for raising the drive housing, hereinafter called the box, and lowering the box into engagement with a wheeled support means such as a wheelchair, whereby it may be moved ambulatory in wheeled support, for normal translatory motion upon the wheeled support as an ordinary wheelchair.

To accommodate the engagement and disengagement of the climbing mechanism with the wheeled carriage for optimum positioning as it approaches the staircase for climbing or descending, the device hereof includes means for lowering the box-like stair climbing means and for moving it horizontally backward (or forward upon com pletion of vertical motion), whereby the climbing means may engage several steps of the staircase while the Wheeled mechanism remains only adjacent below the lower or above the uppermost step, whereby the device further includes means for moving the climbing mechanism laterally forward'or to the rear of the wheels of the chair.

For securely placing the housed climbing mechanism upon the lower or upper steps of the staircase, ready for climbing or descending, the mechanism includes means for raising or lowering the climbing mechanism with re spect to the ambulatory wheel platform comprising, for example, the wheelchair. Moreover, this means allows shifting and tilting to balance the load to be raised or lowered up and down the staircase; for example, the wheelchair and occupant thereof upon the climbing mechanism. The wheeled chair thus has means whereby it may not only move horizontally with respect to the climbing mechanism for adjustment to climbing or ambulatory positions, but means are provided for tilting the chair backward not only to allow balance of the load on the center of the chair-climbing mechanism as it climbs, but also to allow the wheels of the chair to be cleared of the steps while climbing.

Finally, various safety means are included to brake all ambulatory wheeled movements at the top and bottom of a staircase, at points where optimum flexibility of control by the occupant are needed.

It is an object of this invention to provide a stair-climbing mechanism which will allow stable support of an object when climbing and descending a staircase.

It is a further object to combine the stair-climbing means with a wheeled vehicle such as a wheelchair so that the climbing means may be used to carry the wheelchair and an occupant up and down a staircase safely and at the termination of the climbing, the occupied climbing means is converted to an ambulatory wheelchair.

It is a further object to provide a climbing mechanism for a wheelchair housing a driving motor and gearing coupled to an output drive for climbing a staircase, including means for actuating the motor and control elements for an occupant of a wheelchair for climbing a staircase, descending the same, balancing a wheelchair upon said climbing means :and then resetting a climbing box-like housing containing said mechanism closely beneath the wheelchair for ordinary ambulatory use of the device as a wheelchair useful in ordinary horizontal movement controlled by the occupant.

Other objects will be inherent in the description which ensues made in conjunction with the drawings herein provided to be illustrative of the operation of the climbing device, made in conjunction with a wheelchair, as an illustrative example, but not limiting of the use of the climbing device, except as provided in the claims.

FIG. 1 is a side elevation with parts broken away showing a wheelchair combined with :a box-like, stair-climbing mechanism;

FIG. 2 is a front view of the chair of FIG. 1;

FIG. 3 is a top plan view of FIG. 2 with the occupants seat omitted to show the arrangement of parts and operating mechanisms;

FIG. 3a is a detail of a coupling element;

FIG. 4 is :a side sectional view taken upon the line 44 of FIG. 3;

FIG. 5 is a perspective view of the box-like stairclimbing mechanism with some obstructing parts omitted;

FIG. 6 is a top plan view of FIG. 5 showing the stairclimbing drive assembly;

FIG. 7 is a detail taken on the line 77 of FIG. 6 illustrating the back prop raising and lowering drive;

FIG. 8 is a detail illustrating the back prop raising, lowering and locking means;

FIG. 9 is a side view of the box-like housing and a triggering means which hold the back prop in operative position during the climbing movement;

FIGS. 10, 10a, 10b, 10c and 10d illustrate the various positions of movement of stair-climbing and descending of the rail with respect to the box-like housing;

FIG. 11 is a side detail illustrating schematically the preliminary steps for tilting the chair for mounting the steps, including means for lowering of the box-like climbing mechanism and mechanism for tilting the chair and raising the wheels;

FIG. 12 is a side view of a detail illustrating a pivoted gear between means for raising and lowering the box and for moving the box horizontally;

FIG. 12a is a wiring diagram for electrical circuits.

Wheelchair Referring first to FIGS. 1 through 3, a wheelchair is shown with a seat 10 supported between cross and side bars 13 and joining a back 12 with parallel side arm rests 14 and manually rotatable side wheels at each side 16. It is fitted at the forward end with a pair of foot rests extending from vertical support shafts 22, depending from either end 26 of a pivotally supporting cross brace 28. A pair of ears 11 are fixed to the corner of the sides 13 and cross bar 13 and are bored to pivotally support therebetween the shaft 28 and its dependent foot supports 22. Both foot supports are pivotally mounted about a support rod 22 through a frictionally fit sleeve 30 so that the foot supports may be rotated from a usable to an out-of-use position. The shaft 28 extends at opposite ends through a support ear 11 at one side of the chair to terminate in a horizontal pivot pin 29, to which is permanently fixed a crank arm 31, so that by rotation of the crank arm 31 the shaft 28 correspondingly rotates and angularly raises or lowers the leg support 22 and foot rests 20 attached thereto. Foot support 20 is pivotally mounted with a horizontal stop at 32 for folding back out of normal use position. Thus, in normal construction, a wheelchair is provided with the usual arm and leg supports which may be further adjusted for comfort by means, not shown, as known in the art.

Chair tilting structure:

As shown in FIGS. 1, 3, 5, 8, 9 and 11, the climbing and chair control assembly is housed in a box-like structure 75, mounted to a pair of channel iron rectangular frames consisting of an upper stationary chair supporting frame member 47 and a lower frame member 110 supporting the box 75 which slides horizontally ot the rear on rack gears 136 for positioning to mount a staircase. In addition to the side wheels 16, a pair of small rear wheels 34 are supported from foldable vertical braces 36 to rotate upon axle pins 38. The Vertical braces 36 in turn are supported each by a rear brace 40 which pivotally is mounted through an upper arcuate bend 42 to a pivot 44 which is pivoted in the rear end of a side brace 46 extending outward from and in the same horizontal place as frame 47. The rear brace 40 is correspondingly bent at the lower end to engage an upper pivot 50 in the support shaft 36. A forward arcuate bracing member 52 is curved to engage a forward pivot pin 54. The forward end of the side brace 13 and the lower end of arcuate arm 52 is pivoted to pin 53 in shaft 36. Pivotal movement of arcuate arms 52 and 40 with the tilting of the chair and seat 10 will move the rear wheel 34 and support shaft 36 from vertical to raised horizontal position, as seen in FIG. 11.

The support ear 11 (FIGS. 2 and 3) is integrally joined at its lower end to a horizontal bracing arm 11a, spacing the ear 11 laterally to terminate in a parallel second ear 111) from which pivot 54 supports forward wheel brace 52. A stop 60, intermediate the pivots 50 and 58 on shaft 36, in the lower ambulatory position of the rear wheel 34, engages the edge of the forward brace 52 to stop the support shaft 36 firmly in vertical position, preventing any further pivotal movement rearwards and maintains the vertical support 36 aligned for ambulatory support of the roller 34 for movement as shown in FIG. 1. A second stop 61 on the brace 46 engages the arcuate portion 42 at the upper end of the rear wheel brace 40 to secure the upper pivot 50, the vertical wheel shaft 36, and the arm 40 against further rearward movement to maintain it firmly vertical.

The chair 10 is mounted to tilt as shown in FIG. 11 upon its upper track support base 47 from both ends ]of a lower pivot shaft 182 extending across through the opposite channel side 5 of frame member 47. For this purpose a pair of tilting arms 62 at each opposite side of the chair are each pivotally mounted at their lower ends to an end pivot shaft 182 extending through the sides 47 near the forward end thereof and at their upper ends are pivotally fastened one to each of the chair frame sides 13 through a pivot 66 each disposed at about the center of each side 13 of the chair seat frame 10. A tilt linking arm 68 has one end fastened near the upper end of the pivot arm 62 through a pivot pin 70 and the other end of arm 68 is secured through pivot 72 to crank arm 31. (FIG. 2). Thus, referring to FIGS. 1, 2 and 11, the chair may be tilted backwards to the position of FIG. 11, moving pivot arm 62 through crank arm 31 and link 68, which also raises the leg supports 22 therewith in tilted position. During chair tilting movement the rear wheel support arm 40 is drawn horizontally forward until it engages stop 61 on arm 46 which is positioned to. extend laterally from the track support frame 47 a sufiicient distance to engage bracing arm 40. Simultaneously the rear wheel 34 support 36- will be moved horizontally on its lower pivots 50 and 58. The arm 52 in engagement with the support shaft 36 moves slightly forward as the seat 10 is tilted angularly upward. Thus, between the movement of pivots 50 and 58 the support 36 and wheel 34 are turned upward and horizontally as shown in FIG. 11. To accommodate the sliding motion of the rear corner 102 of the chair upon the upper flange of frame 47, a sliding ear (not shown) is pivotally fastened to the corner 102 and has a pair of flanges 48 forming a yoke, of which the lower slides beneath and the upper one upon the upper flange of the frame 47 for sliding support.

Stair climbing means, mounting to chair and positioning The stair climbing means, the box 75 is mounted directly beneath the chair seat 10' interfitted between side wheels 16 and is sized to slide rearward and forward as shown in FIGS. 1 and 11. In normal ambulatory horizontal mot-ion of the chair, the box 75 fits closely under and is dimensionally co-extensive with the frame 47. In that position it is supported by the wheels 16 in substantial clearance of its lowermost ortion 76 above the floor to allow rolling portability of the box unimpededly across a horizontal surface by rolling of wheels 16 and 34. The lateral dimension of the box 75 is sufiiciently narrow not only to clear the distance between the wheels 16, but also to provide space for a pair of track members 78 disposed at each side of the climbing mechanism box 75 as shown in FIGS. 1, 5, 6 8, 9 and 10.

The bottom of the chair climbing box is shaped to correspond to several, here shown as three, step levels 76, 80 and 82, each separated by intermediate riser walls 77 and 81, to correspond dimensionally to a standard staircase. It is desirable to indent the upper riser walls 77 and 81 with narrow arcuate portions 84 and 86 to nest with and accommodate a forward overhanging or protruding lip of a corresponding step of any typical staircase 88 (FIG. 1) over which the bottom configuration of the box 75 is intended to fit and conform without obstruction as it moves stepwise up and down the staircase. Moreover, the indentations 84 and 86 provide a somewhat firmer resting position and, in any case, accommodate the lip-like forward edges, even protective carpeting, frequently encountered upon any staircase step, so that the corresponding vertical riser portions 77 and 81 of the lower end of the box 75 can fit close in snugly against the riser portion of the staircase in climbing. As stated, the box 75 in initial climbing position needs to be positioned against the lowermost steps 88a, 88b and 880 of the staircase 88, the initial position for climbing the stairs. This involves lowering of the box 75 from its normal ambulatory position beneath the wheelchair to the floor or lower step level and movement to the rear of its ambulant carriage position (as shown in FIG. In that position the lower rear wheel 34 of the chair is approximately in contact and engages the riser portion 77 of the first step. Thus, the first steps of positioning the device for climbing is to move the box carriage to the rear so that the box will lie in position above the lowermost steps for engagement thereof, and the rear wheels 34 position the box assembly over the steps so that it will have moved the adequate distance to the rear of the chair needed for this purpose.

Mechanical chair tilting, rocking and box movement means To accommodate this rearward motion of the box, the lower side of the chair 16 is pivotally secured to a frame 47. The chair may be moved pivotally upward to its tilted position of FIG. 11, by rotation of pivot shaft 182 and tilt arms 62 connected to its opposite ends. With the tilting movement the rear corners of the chair slide forward upon the upper flange of the channel 47 to the tilted position of FIG. 11, and the back of the chair moves forward, sliding upon the frame 47 To insure'smooth forward sliding motion, a pair of ears 94 are secured by pivots 96 (FIG. 2), to the frame 13, depending pivotally therefrom, engaging the upper flange of the frame surface 47 for sliding movement of the end corner of the seat to and from the tilt position.

The frame 47 in toto may be formed of channel iron having three closed rectangular sides, open at the rear, and has a centrally disposed cross brace 106 (FIG. 3). A pair of downturned vertical rack gears 108 depend from brace 106 with teeth mounted on the forward surface, with spur gears 162 and 164 on a countershaft 148 constituting a raising and lowering mechanism for the box 75, as better shown in FIGS. 4 and 12. A box carriage consisting of a lower channel frame member 110 is disposed immediately below, and is similarly sized and movable parallel downward from the frame element 47. It is also of channel iron shape. Both frame elements 47 and 110 as shown in FIGS. 1 and 11 are joined together by a lazy tong raising and lowering means comprising one diagonal arm 112 pivotally fixed at its lower end through pivot 114 to the channel member 110 and slidably fixed at its opposite end in a slot 116 through a sliding pin 118, which slidably engages the slot 116 in frame 47. A cooperative lazy tong arm 120 is pivotally fixed at its upper end through pivot 122 in the upper frame member 47 and slidably fixed through slot l24'through sliding pin 126 in the lower frame element 110. A central pivot 128 pivotally secures both lazy tong arms 112 and 120 together at their centers. The action of the lazy tong bars will be to raise and lower the frame 110 with respect to upper frame 47 which is always maintained horizontal and stationary.

The frame 110 similarly of channel iron is rectangular and open at the rear end, the latter braced at its upper edge by a cross bar 130 which in turn supports a gear drive housing 132 (FIG. 3). The lower flange element of the channel iron 110 slidably supports a rectangular frame member 134, preferably of angle iron, the open angle directed upward and inward. Two parallel sides of frame member 134 each has a rack gear 136 fixed thereon for cooperation with a driving spur gear 138 mounted for drive on counter shaft 148. The sliding frame 134 has the upper edge of the box firmly fastened thereto by several fastening ear members 137 disposed at the front and rear edges.

The lower frame member 110 is further braced by a forward intermediate cross bar 140 which has downturned ends 142 which firmly engage the top of the channel 110 and support the bar 140 upward in about the plane of the frame 47. The downturned ends 142 of brace 140 (FIGS. 4 and 12) are bored to receive a pivot shaft 144. Fixed to pivot shaft 144 for rotation therewith are a pair of arcurate pivot arms 146. The lower end of pivot arm 146 pivotally supports a pivotally swinging drive 148 which carries both spur gears 164 aligned thereon for meshing with vertical rack gears 108, and also carries spur gears 138 aligned for meshing with horizonal rack gears 136. By pivotal movement of pivot arms 146 and pivot shaft 148 to an upper position, spur gears 164 will mesh with vertical rack gears 108 for raising and lowering of the lower frame 110 and box mounted thereon vertically; lazy tong arms 112 and 120 fol-ding and unfolding to accommodate the raising and lowering of the lower frame 110. When pivot arms 146 are at the lower pivotal position, the spur gears 138 will mesh with horizontal racks 136 for horizontal drive thereof. A small electric driving motor 150 is firmly mounted to support frame element 132 to drive through a series of reduction gears 152 through a final output gear 154 to supply slow rotary output, which connects through shaft 156, thence through a similarly rotatable coupler 158, through shaft 160, terminating in a beveled pinion gear 162 which engages a ring gear 165 fixed to rotatably drive the pivot shaft 148.

The pivot shaft 148 suspended on pivots 146- has spur gears 138 at an extreme end fixed to shaft 148 and inner spur gears 164 fixed at inner positions on shaft 148 as shown in FIGS. 3 and 12. A sprocket gear 166 is mounted axially slidable but splined to pivot shaft 148 as controlled and will rotate with the shaft 148 when a clutch means 168 is engaged as shown in FIG. 3. A clutch throw-out collar wheel 170 is also rotatably mounted and fixed to the spur gear 166 for movement axially by a forked end clutch throw-out arm 172 operated from a hand control lever 174 (FIGS. 3 and 12) which manually may move the clutch 168 laterally into engaged or disengaged position. The clutch throw-out lever 174 is held within a slot of a pivot shaft cage 176 (FIG. 3) which has a rectangular shape allowing both the crosswise movement described for engaging and disengaging the clutch 166 as well as forward and rearward movement. The cage 176, however, is supported pivotally by a link arm 177 (FIG. 12) pivotally fastened to an intermediate part of rear pivot arm 146 which supports the rear end of the pivot shaft 148, so that upon movement of the control lever 174 forward, it will cause the pivot shaft 148 to be depressed downward with pivot arms 146. In the downward position the spur gears 138 will engage the racks 136 and move the same either to the rear or on reverse rotation, forward, depending upon the direction of rotation of the motor 150. When the control level 174 is moved in the revers direction, the pivot shaft 148 is raised upward on pivot arms 146, in which position spur gears 164 will engage the vertical rack gears 108 and will cause the frame member 110 to move up or down on its lazy tong pivoted arms as shown in FIG. 11 together with the box 75 fastened thereto, again depending upon the direction of rotation of motor 150. Thus, by manual operation of control lever 174 the box 75 is lowered or moved to the rear or forward to assembled position as shown in FIGS. 11 and l.

A sprocket chain 178 may be entrained around both gear 166 and a forward sprocket gear 180, the latter being rotatably fixed to rotate with a chair tilt drive shaft 182 which extends at opposite ends through the frame member 47 and is rotatably supported therein with each and engaging pivot shaft 62 for imparting a tilting pivotal movement to the chair frame By lateral movement of the hand lever 174 engaging the clutch 168, rotary power is imparted to shaft 182 through the sprocket chain and gearing to impart tilting movement to the chair 10. The sprocket chain 178 may be loose enough to accommodate lateral movement of gear 166 on shaft 148 for purposes of disengaging the clutch 168.

A lock assembly 216, shown in detail in FIG. 3, is provided for locking the chair in tilt position, FIG. 4. For this purpose a lateral translational shaft 218 is mounted to lie upon and move parallel to support beam 106. The inner end is provided with a shoulder 220 and is positioned to be intercepted by operating level 174 in lateral movement, whereby the shaft 218 is moved longitudinally therewith along beam 106. The shanking of the shaft 218 is slotted at 222 to receive a retaining pin 224 mounted in sliding fit in slot 222, slidingly retaining the shaft 216 in longitudinal movement. The end of the shaft 216 is bored to receive a downturned arm of a rotary toggle 236 mounted to rotate about pivot pin 237, the opposite arm of the toggle being fixed in a bore 226, imparting corresponding longitudinal motion to a second actuating shaft 228. The shaft 228 is similarly mounted to slide upon the cross brace 106 and is similarly slidingly pinned thereto by a pin 230 within a sliding slot 232, thereby allowing sliding longitudinal movement parallel to and displaced the radial distance of said toggle 236 from the shaft 218. A spring 238 biases the toggle and shafts into actuating engagement with the control shaft 174 in its normal central inoperative position. A chair tilting locking pin comprising a bent angle shaft 242 is integrally secured to the end shaft 228 and is simultaneously moved laterally opposite as the control lever 174 is actuated laterally. The dimensions of the several levers and support of the locking rod 242 is such that the rod 242 will lie directly in back of the corner end 102 of the chair in tilt position as shown in FIGS. 3 and 11. Thus, the end 102 of rod 242 will lie behind the corner and will lock the chair in the tilt position when the control lever 174 is in neutral vertical position and will be withdrawn from that locking position when the lever is depressed laterally.

When the chair is in normal ambulatory horizontal position, another locking device 190 is operative to main tain the chair locked to the horizontal position and the spring 238 will bias the locking rod end 242 to merely slide against the side frame 13 without locking effect thereon.

In reverse direction of rotation, motor 150 and shaft 182, lowering tilt arms 62, the chair is returned to normal horizontal position. By holding the shaft 174 relatively vertical, the clutch 168 is maintained normally disen gaged. The shaft 182 (FIGS. 3 and 4) has fixed thereto a cam member 184 fastened eccentrically at each surface to one end of a pair of spring-like disengaging arms 186.

A latching bar 188 having a latching lip 187 is slidably mounted in a locking cage 190, which in turn is securely fastened to the forward end of frame 47. A compression spring 192 is secured about the locking bar 188 to bias the latch lip 187 outwardly, engaging the upper surface of the forward frame element 13 to latch it. A pair of lateral pins 194 extend laterally from each side of and are fastened to the latching bolt 188 to be engaged one each by the curved surface of a spring-like disengaging arm 186, each arm 186 being fixed for rotation in a pivot 196. As thus described, the continued rotation of shaft 182 in chair-tilting direction, simultaneously rotating cam 184 forces the latch engaging arms 186 downward and thereby the inner curved body of arms 186 engage pins 194 which force the latching bar 192 to move in reverse direction against pressure of spring 192, as the arms 186 turn downward with cam 184, releasing the latching bar lip 187 from engagement with the forward frame surface 13, thereby freeing the chair seat for pivotal upward tilting rotation from frame member 47. Upon reversal of drive of shaft 182 and return to normal horizontal seated position of the chair, the latching member 187 on frame 47 will reengage the forward frame portion of the chair 13 and lock it in horizontal position.

Upon movement of the control lever 174 to the rear, the spur gears 164 will engage the vertical racks 108 and rotation of shaft 148 through clutch 166 will raise or lower the box 75. A braking means is provided to fix the vertical position of the box 76, which comprises a set of vertically disposed serrated teeth 196 each mounted on a horizontal sliding bar 198 and coupled together by a spring shaft 200 lying upon and slidingly held thereon by sleeves 202 at each end upon cross brace 140. A retaining bracket 206 extends outward from the cross shaft having a turned up collar 208 to receive the center portion of the flat end of a spring member 210 having bent ends lying against the edge of bar 200 biasing bot-h sliding bars 198 and teeth 196 against vertical rack gears 108, thereby locking the carriage frame 110 and box in fixed position upon the vertical gears.

The sliding shafts 198 each have a hole 212 in an outer end (FIG. 3) which receive and secure thereto the end of a cable 214, the cable body being trained through a guide slot 216. The opposite end of the cable 214 is fixed to the lower ends of each corresponding pivot arm 146 (FIG. 12). When the control arm 174 is moved to the rear, thus causing the spur gears 164 to engage the vertical racks 108. The upward pivotal movement of arms 146 draw upon the lower end of the cable 214, as the pivot shaft 148 is moved upward therewith and, thus, simultaneously disengages the serrated teeth 196 braking hold upon the racks 108. Thus, as described, the vertical movement of carriage frame 110 and box 75 available through rack gears 108 is continually stopped by the breaking contact of teeth 196 in bars 198 biased by spring 210 against the racks 108, except when positive vertical drive is applied by spur gears 164 against the racks 108 for raising or lowering the box 75 and its carriage frame 110. Upon termination of the vertical drive effect, the brake immediately is applied by the spring bias of spring 210 upon bar 200.

Thus, it will be noted that the reversible driving motor 150 imparts power for drive through pinion 162 and ring gear 165 for operation of the several motions controlled by lever 174. In clutch position, other than vertical, it controls the tilt and horizontal positioning of the chair by lateral movement. In forward positioning of the lever 174, it controls the drive of the horizontal gears 136 to move the climbing box to the rear for engagement of the steps, or reassembles the climbing box for ambulatory motion of the box upon its wheels directly beneath the chair. Upon movement of control lever 174 to the rear, the pivotal shaft 148 is moved upward for engagement of the vertical drive with racks 108 as described.

The ring gear 165 has long teeth to accommodate pivotal movement of shaft 148 so that the pinion 162 may slide inward and outward against the teeth of gear 165 without losing meshing contact therewith.

Stair climbing safeguards It is desirable for a stair-climbing chair, where the wheels are deliberately lifted from support position during climbing, the device resting on the chair climbing box, on the staircase, and upon approaching the top of a staircase for descent, to provide maximum safety whereby the chair itself will sense the presence of the floor ready for movement upon its wheels; and will lock automatically where the support of the floor has terminated; for instance, at the top of a staircase ready for descent. For this purpose, and referring to FIGS. 1, 2 and 3, the wheels 16 are each supported from a central hub 250 upon an axle shaft 252 fixed to a horizontal bracket 254 in turn supported by forward bracing 52 so that the wheels 16 move arcuately upward with the brace 52 and with the front end of the chair 10 as it is carried upward to the tilt position. Locking sprocket wheels 256 are mounted to the inner sides on shafts 252 to rotate with the hubs 250. Each of the sprocket wheels 256 have teeth curved on a vertical edge 258, in the direction of reverse rotation of wheels 16, and a straight side on edge 259 to cooperate with a locking bar 260. The locking bar 268 as shown in FIGS. 1 and 3 supports an inner frame 262 which fits around one of the teeth of a locking sprocket wheel 256. The forward end of the frame 262 terminates at the center of the sprocket to form an abutment against a vertical sprocket tooth surface 259 in its vertical 12 oclock position, preventing, as an abutment, any further rotation of the sprocket wheel 256 in the forward rotational direction, so that each wheel 16 becomes locked against forward rotation when the locking bar and frame 260 are lowered to engage the vertical surface of a tooth 259. In the reverse direction, the wheel is free to rotate so that the locking effect is only against forward rotational motion only. The locking bar 254 supports a vertical sleeve 266 at its forward end which slidingly receives a vertical reciprocable locking rod 268 which at its lower end 270 senses the level of the floor. When the floor is not present to intercept and support the vertical position of the rod 268 holding the bar 260 and frame 262 in its upper position, to stop its further descent, the locking bar 260 attached to rod 268 will have descended to locking position upon the locking wheel- 256. Where, however, the floor level is reached at a higher position in normal translational rolling movement of the chair upon the floor, the locking bar 260 will normally be held by the floor level upward and out of engagement with the locking wheel 256; so that the wheel 16 will be free to rotate.

Stair climbing means Referring to FIGS. 1, 5 and 10, the stair climbing mechanism is housed within the box 75, have sides and ends at shown, but may be open or closed both at the top and bottom, but which by its bottom contour corresponds to the stepwise shape of a couple of steps to be climbed and therein is an essential operating element, cooperating in the stepwise climbing of the staircase. To this end the bottom of the box has a lowermost step level 76, as referred to above, an intermediate step level 80 and an upper step level '82 corresponding to the steps of the staircase, each joined by vertical correspondingly shaped step riser elements 77 and 81 connecting the step elements 76, 80 and 82. Thus, the step levels 76, 80 and 82 are all adapted to lie upon and snugly fit upon a staircase 88 as shown in FIGS. 1 and 10.

As will appear, the box is designed to move up or down the staircase progressively one step at a time, despite its bottom configuration to rest upon and lie against three steps at a time of the staircase. The selection of the three step configuration is for optimum safety and stability. It will operate approximately as well, and can be redesigned according to the principles hereof, to operate against two steps with slight loss of stability, or against four steps with even more stability, as desired.

For operation of the structure shown with three steps, the box contains operating means driving a pair of horizontal rotary output shafts 274 and 276 extending laterally from each side, each of which terminate in pivotally supported crank pins 278 and 280 on each side of the box respectively, being each interconnected eccentrically to output shafts 274 and 276 in any suitable manner for displacement through arcuate or circular arm 2'82 and 284. The arcuate arm drives are structurally convenient by imparting a spring-like resilience to the eccentric drive, but is not otherwise essential. Any interconnecting displacement rod for connecting a crank pin 278 or 280 with an output shaft 274 and 276 will suflice. A further advantage in the arcuate structure of the crank arms 282 and 284 is the increase in safety from possible interference of irregularities in the step to inhibit somewhat rotary motion by the presence of a rug or interference by some object or obstruction by which a crank arm might be intercepted. The likelihood of such interference by step irregularities is reduced to a minimum by the arcuate arms 282 and 2-84.

The crank pins 280 and 282 are each pivotally secured through a sleeve bearing to upper and lower positions respectively on a track member 78, one disposed at each opposite side of the box 75, and each engaged at upper and lower step heights correspondingly by crank pins 278 and 280, so that both tracks at each opposite side 78 will be actuated simultaneously in unison, each being displaced to exactly the same vertical step degree to avoid all possible variation or eccentricity in movement of one track member from the other. A front cross bar 286 is mounted across both tracks and extends even in any eccentric displacement position an adequate clearance distance from the forward surface of the box 75. The cross bar 286 has a bend 288 adapted to allow clearance of an electric cutout switch 290 which, as will appear, extends outward from any step edge from the forward side, and vertically below the surface 76, to engage the floor after termination of descent of the box to terminate the mechanical descending motion.

In preparation for ascending the steps, the occupant of the chair will wheel the chair back until the rear wheels 34 engage the lowest riser 77 of the first step 80. By operation of the control lever 174 moving it in the forward direction, lowering the pivot shaft 148 arcuately downward whereby spur gears 138 engage the rack gear 136, the box 75 is attached thereto through forward ear-like brackets 137 and after ear-like brackets 139, as shown in FIGS. 1 and 5. Directly above the staircase, that is, above the position as shown in FIG. 1, after the rack gears 136 have been driven to completely move the box to a position over the stairs, the box is then lowered by moving control lever 174 in the reverse direction, thereby causing spur gears 164 to engage vertical rack gears 108, simultaneously releasing the brake mechanism as described, and allowing the box to descend to resting engagement upon the first three steps of the staircase as shown in FIGS. 1, 5 and 10.

Thereafter the control lever 174 is moved back to the central neutral position and then to the right, causing the clutch 168 to become engaged, driving thepivot shaft 182, simultaneously unlocking the horizontal lock .190 by releasing latch 188, and also drawing back bar 228 to release the lock angle 242, whereby the chair tilts to the position shown in FIG. 11 with the wheels raised. The control lever 174, then returned to vertically normal postion, causes the locked angle 242 to engage the back of the chair, locking and preventing release of the chair from its tilted position of FIG. 1. Finally, the control lever 174 is moved again in the direction forward and motor 150 is reversed, whereby the spur gears engage the horizontal racks 136 and the tilted chair sliding on frame 110 is moved back to the aligned position of the upper and lower frames 47 and 110 as shown in FIG. 11, balanced over the box. The last step of the preparation to climb operation consists of lowering the frames 47 and tilted chair thereon to the lowered position of the lazy tong arms by moving the control lever to the rear with motor 150 still driving in reverse, engaging the spur gears 164 on vertical racks 108 again and thereby lowering the upper frame 47 upon the lower frame 110 and box 75, the entire assembly now resting upon the lower staircase steps, the chair balanced in locked tilted position ready for ascent.

The box operating mechanism now actuated, eccentrically moves stepwise; first the box is lifted up to the next higher step and then the track, as shown in the diagram, stepwise of FIGS. 10a, 10b, 10c and 10d. In that position shown for take off, FIG. 10a, the lowest end of the tracks 78 will lie upon the floor surface with the box 75 resting on staircase steps, step surface 76, 80 and 82. As the output shafts 274 and 276 rotate, the box is first lifted eccentrically upon its lower and upper crank pins 278 and 280 as pivots, moving upward and to the rear, reaching an upper step position as shown in FIG. 10b. It will be seen that the crank pins have actually moved from a 9 oclock position of FIG. 10a to about a oclock position of FIG. b in transferring the box upward to the next step. With continued rotation of the crank arms, the track then begins to be lifted while the box remains stationary. Thus, when the crank pins have reached about a 1 oclock position and the track is intermediately raised as shown in FIG. 10c, and then completes its intermediate climb, moving the tracks 78 almost completely to the next step, it moves from the 1 oclock position of FIG. 10c to the upper track position of FIG. 10d, whereby the box and track have now completed the climb and are ready to move another step as shown in FIG. 10a. Thus by continuous rotation of the cranks, the'chair, box and track take single steps first of the box and then of the track as the device moves very steadily and stably up the staircase.

For descending the steps, the normal descending operation, after starting the descent is merely the exact reverse of that described for ascending. After climbing or descending, the operator again raises the chair from the box and relevels the chair frame 110, reversing the tilting motion of the chair until the wheels then contact and rest upon the fioor,-reversin-g the movement of the box to the closed position of FIG. 1, whereby the box is assembled with the chair for horizontal ambulatory movement. It will be noted that in the reverse direction descent of the stairs, it is the track which descends first as the first step, the box following, but the preparation for descent and the handling of the box upon reaching the top of the stair is different as will appear.

Stair climbing and descending drive The driving mechanism to actuate the output shafting 274 and 276 is shown in FIG. 6 and comprises driving motor 300, supported by brackets 302 from the forward wall of the box 75, having a spur gear 304 mounted on its armature shaft 306 which meshes with a train of reduction gears 308 to finally mesh at substantially reduced speed with a final reduction gear 312 fastened to output shaft 276. A ring side gear 314 fastened to shaft 276 for rotation therewith meshes with spur gear 316 at the upper end of coupling shaft 320 and transfers and couples the rotation of shaft 276 with shaft 274 throughout spur gear 318 meshing with a reversed ring side gear 322 fastened thereto. Thus, both output shafts 274 and 276 are positively driven through direct reduction gearing by electric motor 300 at substantially reduced speed. The coupling shaft 320 is supported in a bushing for free rota- 12 tion 324 in the end of a bracket 326 secured to the side wall of the box as shown.

The operating circuit for motor 300 is a duplex circuit both of which are completed through an operators control switch 292 mounted conveniently, wherever desired, for example, on the arm rest 14 near the hand of the operator. Closing of the switch 292 will then actuate one of the duplex circuits if it is otherwise completed through the second circuit for operation. One of the motor control circuits is completed through a floor switch 290. The circuit through switch 290 is open when the box is out of contact with a step. The second circuit to motor 300 is made and broken by an outer switch arm 294 and an inner switch arm 297 carrying a circuit completing contact 295 when the outer arm 294 extends coaxially with the inner arm 297 to which it is attached by hinge 299. A slot 296 is cut in the wall of box 75 through which the arm 297 is extended as shown from a slot and subhousing 296 within the box 75. The arm 294 is extended through slot 296 and may extend outward by actuation of a backdrop mechanism, as will appear. In that extended position the arm 294 will be intercepted by movement of the upper ends of track 78, the outer arm portion 294 being bent downward on its pivot 299' to break the circuit to motor 300 through contacts 295. Thus the second circuit broken by operation of the track is shown. In extended position of arm 297, the circuit is made, and only when bent at its joint 295 is the circuit broken. The inner arm 297 is extended or withdrawn into slot 296 as actuated by the said backdrop, but when it is withdrawn within the slot, the position of the second circuit closed through contacts 295 is always maintained except for the instance when it is positively broken by movement to intercept track 78 by either motion of climbing or by direct lowering of the backdrop as will appear. The hand switch 292 may be a reversing switch so that pushed forward it will direct the current in one direction to the motor 300 whereby it will drive the shafts 274 and 276 in a direction to ascend the stairs, and in opposite movement will reverse the switch for opposite rotary motion in descending. With switch 290 inactive, the circuit will be completed to motor 30 through switch 294 in active position as explained, except in specific instances as will appear. After the box has begun to ascend and lower switch 290 is in contact with the stop, the circuit to the motor will remain closed, and the motor 300 will be actuated through either circuit.

A backdrop bar 362 (FIG. 8) is provided to support the box and chair at the top of the staircase, and is normally held in folded (dotted line) position for climbing and other operations. For actuation thereof, a shaft 328 is mounted for rotation between the sides of the box 75, parallel to and above output shaft 276. A triggering arm 330 as shown in FIGS. 6, 7, 8 and 9, extends downward from the pivot through a curved body to below the step line level 80, to intercept the top of a stair in substantially every position of movement of the box as it passes up the staircase in climbing to remain substantially housed within the open bottom section 80 or protruding therefrom sufficient to engage the top of various portions of the staircase as the box ascends only a limited distance.

The lower curved end triggering arm 330 is fastened through a horizontal eye 334 to one end of an arm or link 336 which is pivotally secured to move slidingly with shaft 338. The ends of the shaft 338 are slidably supported for horizontal movement in slot 342 in one side wall of the box 75 (FIG. 9) and at its opposite end in a slot 344 Within a framing support 346 for the reducing gear drive 308, the framing element 346 being fastened to the box walls in forward bracket 348 and side bracket 349. Thus, as the trigger arm 330 contacts and rides upon the step surfaces in upward movement, and in stair contact holds the sliding shaft 338 at an intermediate point of the slots 344 and 342, a position is shown in which an wheels the chair upon the surface near to the top step, a position where both the locking supports 268 extend beyond the top step and drop to a lower locking position upon locking teeth of wheels 256, thereby securing the wheels against further rolling movement. The backdrop 362 is then lowered by manually operating control arm 161 to cause the coupler 158 to move the driving pinion 167 (FIGS. 3a, 4, 6 and 8) into engagement with gear 378 keyed to shaft 328 which rotates spur gear 380 which in turn rotates idler gear 358, eccentrically lowering the backdrop 362 from its folded position at the supporting position of FIG. 8 through movement of link 370. Simultaneously, the switch arm 294 is turned by gear 384 in mesh with worm gear 382 to the extended dotted line track intercepting position of FIG. 6 to be engaged by the end 402 of the track 78 and breaking the motor 300 circuit through switch 295. Thereafter the box 75 is lowered to the floor as described for ascending and the chair is then moved to pivotal position of FIG. 11. Switch 290 extending over the staircase allows activation of the first circuit and hand switch 292 is activated to cause motor 300 to operate in reverse direction which causes the track 78 to move in reversed direction down onto the first step and then the box follows in that sequential cycle until the assembly reaches the bottom of the staircase as described for FIGS. 10a and 10d.

As the descending operation begins by activating the motor 300 to first move the track down upon the first step, switch arm 330 will not have engaged any step, as shown in FIG. 9, and sliding shaft 338 will be forward with spur gear 356 meshing with sectional gear 352, but rotating in reverse direction, whereby the lowered backd-rop as shown in FIG. 8 will be raised by the reverse motion of idler gear 358, and thereby will automatically be raised to the folded position of FIG. 5. Simultaneously, the reverse drive upon spur gear 380 will retract the extended switch arm 297 within the slot housing 296, closing the second circuit for further descending operation, the reverse of ascent.

FIG. 12a is a detail of the basic wiring showing the electrical connection of the motor 300, shown as the motor M, controlled by the several switches as described above. For instance, the switch 90 is shown here as 381, switch 385 corresponding to contact 295, and hand switch 292 corresponding to switch 390. By that arrangement it is clear that the motor M will be inoperative when any of the switches 380, 385, and 390 are open breaking the circuit to the motor M.

I claim:

1. Stair climbing and descending means comprising a combination of a housing and drive means therein, said housing having its bottom shaped to rest in stable support upon a plurality of steps and interconnecting risers of a staircase in a vertically disposed series, a track member on each side of said housing correspondingly sized and shaped to a similar number of steps and interconnecting risers, said drive means being coupled through the sides of said housing eccentrically to both tracks, synchronously driving said tracks in alternate cycles to lift said housing to the next higher step in eccentric movement of said eccentric coupling elements upon said tracks while said tracks are held stationary as a supporting base for said housing, and then to lift said tracks to the next higher step with said housing held stationary as a supporting base for said tracks in continuous stair climbing movement, said cycles being reversed in stair descending movement.

2. Stair traversing means as defined in claim 1 having a backdrop foldably disposed beneath the upper step conforming end of said housing, sized to support the upper end of said housing when dropped into a stable resting position on a horizontal surface support at the top or bottom of a staircase, and means further actuated by said drive means to rise and lower said backdrop when horizontal support is needed.

forming end of said housing and sized to support the upper end of said housing when dropped into a stable resting position on a horizontal support surface such as at the top or bottom of a staircase, means further actuated by said drive means to raise and lower said backdrop when horizontal support is needed, and a triggering arm positioned to be engaged by the steps during climbing movement and to hold said backdrop drive inactive to lower said backdrop during said stepclimbing movement.

4. Stair traversing means as defined in claim 1 wherein the said drive means comprises an electric motor drivingly coupled eccentrically to said track, an electric switch means comprising a switch arm simultaneously movable to extended position engageably by movement of said track to break the circuit to said motor simultaneously with the lowering of said backdrop when the top of the stairs is reached in climbing.

'5. Stair traversing means as defined in claim 1 combined with a wheelchair, means for securing said stair climbing means beneath said chair whereby the assembled chair and stair climbing means is ambulatory in horizontal movement.

6. Stair climbing means as defined in claim 1 combined with a wheelchair, means for securing said stair climbing means beneath said chair whereby the assembled chair and stair climbing means is ambulatory in horizontal movement, said wheelchair being mounted on the top of said housing pivotally to allow tilting of the chair from horizontal ambulatory position to titled angular position, balanced on said stair climbing means during step climbing movement thereof.

7. Stair climbing means as defined in claim 1 combined with a wheelchair, means for securing said stair climbing means beneath said chair whereby the assembled chair and stair climbing means is ambulatory in horizontal movement, said wheelchair being mounted on the top of said housing pivotally to allow tilting of the chair from horizontal ambulatory position to tilted angular position, balanced on said stair climbing means during step climbing movement thereof, and means for raising, lowering and horizontal sliding of'said stair climbing means and track beneath the wheelchair, preparatory to mounting, climbing and descent of a staircase.

8. Stair traversing means as defined in claim 1 including a wheelchair comprising a seat and wheels attached thereto for horizontal ambulatory movement, said chair being secured to said housing, means for sliding said housing forward and to the rear of said chair, means for tilting said chair to balanced position on said housing, said tilting means including means for folding the wheels of said chair out of ambulatory support position preparatory to changing from ambulatory to climbing movement of the assembly.

9. Stair traversing means as defined in claim 1 including a wheelchair comprising a seat and wheels for horizontal ambulatory movement, said chair being secured to said housing means for horizontal sliding movement of said housing forward and to the rear of said chair, means for tilting said chair to balanced position on said housing, said tilting means including means for folding the wheels of said chair out of ambulatory support position preparatory to changing from ambulatory to climbing movement of the assembly, and means for locking the chair to said assembly alternately in horizontal position for ambulatory movement and in angularly tilted position for stair climbing movement.

10.'Stair traversing means as defined in claim 1 including a wheelchair comprising a seat and Wheels for horizontal ambulatory movement, said chair being secured to said housing means for horizontal sliding movement of said housing forward and to the rear of said chair, means for tilting said chair to balanced position on said housing, said tilting means including means for folding the wheels inner spur gear 350 keyed to shaft 338 is held out of mesh with a sectional gear 352 fastened to output shaft 276.

A spring 354 biases the sliding shaft 338 and gear 350 into engagement with the sectional gear 352 so that upon release of the triggering arm 330 from engaging pressure upon the steps of the staircase, the shaft 338 and spur gear 350 will slide into driving mesh with the sectional gear 352. At the right side wall of the box 75 as seen in FIGS. 6 and 9, the sliding shaft 338 extends through slot 342 for sliding support. A second spur gear 356 is keyed to the right end of shaft 338 and slides in slot 342 as well as rotates with shaft 338 so that it is stationary when shaft 338 is held out of contact with sectional gear 352 by arm 330, but rotates when sectional gear 352 meshes with spur gear 35% The spur gear 356 then meshes with a large speed-reducing gear 358 which is supported on a sleeve bearing 360 for free rotation upon driving output shaft 276, independently of shaft 276 as it is driven by sectional gear 352 when meshing with spur gear 350.

Sectional gear 352 is permanently keyed to output shaft 276 for continuous rotation therewith. However, it is timed and positioned thereon for initial tooth alignment approximately when the upper crank pin 280 is at a position between 9 and 1 oclock, and track 78 has been moved to a position allowing emplacement upon the steps; and the continuing cycle would then begin to lift the box upward for the next step; that is, the beginning position of FIG. 10a. At that point the box having reached the uppermost step of the staircase, it is necessary to provide for lowering of backdrop support 362 (FIG. 8) for the box as the rear end of the box lifts above the topmost step. For this purpose, while the steps are in the process of being climbed, the sliding shaft 338 is held by the trigger arm 330, riding on the step surfaces, out of meshing contact wtih the sectional gear 352. The backdrop 362 comprises a horizontal bar 364 which is attached to arms 362, horizontal but in raised out of use (dotted line position of FIG. 8) which become vertical arms when the backdrop support is lowered. The arms 366 attached to bar 364 are pivotally connected at 368 to the inner step surface 80 as it joins the riser wall of the box 81. In step climbing position the backdrop 362 is maintained folded upon its pivot 368 beneath the upper step surface 82 of the box, as shown in FIG. 8. In that position switch arm 297 and 294 remain housed within the box 75 in straight contact circuit completed position to motor 300 as shown in FIG. 6. An arcuate connecting link bar 370 is pivoted at 372 to an intermediate point of backdrop arm 366, and at its opposite inner end is pivoted eccentrically at a point near the gear teeth 374 upon the t idler gear 358.

In operation of the backdrop, as the climbing box 75 and chair therein reaches the topmost step of the staircase, and the box undersurface 82 begins to rise above the topmost step, the pressure of the step surface against trigger arm 300 is released, allowing the sliding shaft 338 to move rearward in its sliding slots 342 and 344, meshing of spur gear 350 with the sectional gear 352 and spur gear 356 with idler gear 358. The consequent rotation of shafts 274, sectional gear 352 and spur gears drives idler gear and link arm 370 downward, lowering the backdrop to floor support position of the end of the box 75. This movement is that of :dotted line to full line position of FIG. 8.

Moreover, as the idler gear 358 is forced to rotate by spur gear 356, it will also force rotation of spur gear 380, in a direction which in turn will drive shaft 328, worm gear 382 thereon, and spur gear 384 meshing therewith, to force the switch arm 294 and 297 outward of the slot 296, in the dotted line position shown in FIG. 6. The arm portion 294 thereof then will extend into the pathway of the continuous moving track 78 so that as the box lifts above the last step and the backdrop 330 is lowered, the track will strike the arm 294, bending it downward on its pivot 299 to separate the contacts 295, opening the second circuit and inactivating the driving motor 300. Thus, as the box continues to climb above the uppermost step, the backstop is positively driven into full and support position so that the box will remain stably supported horizontally above the top step of the staircase.

Upon reaching this point the control lever 274 is actuated to drive the chair back to horizontal support position as described. As the chair reaches horizontal support position, both wheels become lowered to touch the upper front portion above the staircase, but locking arms 268 have descended below the top of the stair and will maintain the frames 262 looked upon toothed locking wheel 256 as described. In that position the occupant of the chair will merely roll the wheels backward to release the lock and thus automatically disengage the locking supports 268. As they reach the floor level position, the chair will be able to be manually rolled off.

In this position the backdrop 362 may be raised by a manually controlled backdrop raising mechanism. For this purpose coupler 158 (FIGS. 3 and 3a) is mounted to freely swivel through a swiveling arm 157, to which is linked a hand actuating lever 159 which extends upward to a point near the hand of the operator (not shown) through the bent arm portion 161 for hand control by the chair occupant. The ring gear 163 is mounted in continuous driving rotation by output shaft 156 which meshes with an idler pinion 165 which in turn drives an opposite pinion 167 on an idler shaft 169 supported for rotation within a bushing 171 in the coupler frame 173. The output idler pinion 167 thus is moved into coupling and uncoupling engagement with a gear 378 (FIG. 6) keyed to drive shaft 328 on which is mounted a spur gear 380 in mesh with idler gear 358. As the coupling frame 173 is manually rotated for engagement of the pinion 167 with ring gear 178 to drive the shaft 328, spur gear 380 thereon and idler gear 358 will be caused to rotate in reverse direction, and the backdrop bar 364 will thus be raised to the dotted line position shown in FIG. 8. Simultaneously a vertically mounted worm gear 382 meshes with a spur gear 384 for rotation by shaft 328 (FIG. 6). In this direction of rotation the switch arm 294 and 297 attached to the pivot shaft of 384 is turned inward of the slot 296 to the position shown, completing the second circuit.

As the box moves above the staircase with forward end 76 resting upon the upper front 386 and backdrop 364 is lowered into contact with the floor, as described, switch extending over the open space of the top step is expanded by its spring into circuit closure to motor 300, but switch 295 has been bent on its hinge 299 out of contact position by movement of the track in its last step rotation. The box bottom surface 76 contacts the floor at the top of the steps and is supported between the backdrop 364 and the forward surface of the box 76. In this position, a braking element comprising a vertically slidable shaft 388 mounted for vertical sliding movement about a pin 3% slidingly fitted within a slot 392 in the shaft 388 allows vertical sliding movement of the shaft 388 when a footpiece 394 is engaged by the fioo-r of the upper step portion 386. A spring 394 attaching to a cleat 396 and pin 398 biases the shaft 388 downward, and the upward pressure of the floor 386 upon the footpiece 394 moves the shaft 388 vertically upward against the tension of spring 394. A braking shaft comprising a serrated toothed bar 396 has its forward end pivotally secured to the side of the box to pivotally support the inner end of the braking bar 396. When the footpiece 394 is moved upward by the floor together with freely movable outer end 480, pivotally attached to the upper end of braking bar 394, the bar surface is moved into frictional engagement with the teeth of idler gear 358, preventing rotation of idler gear 358 in upper staircase position. It is from that position that the chair and box are returned to ambulatory position.

For descending the staircase the operator of the chair of said chair out of ambulatory support position preparatory to changing from ambulatory to climbing movement of the assembly, means for locking the chair to said assembly alternately in horizontal position for ambulatory movement and in angularly tilted position for stair climbing movement, brake means for locking said wheels against rotation in horizontal ambulatory position, and means sensitive to the floor level for actuating said braking means when the floor level support is discontinued during staircase climbing and descent.

11. stair climbing means as defined in claim 1 combined with a wheelchair, means for securing said stair climbing means beneath said chair whereby the assembled chair and stair climbing means is ambulatory in horizontal movement, means for raising, lowering and sliding said stair climbing means and track horizontally to the rear from beneath the chair, preparatory to mounting of the steps, means for tilting said chair to balanced position on said stair climbing means for mounting of the steps, and independent drive means alternately connectable to said means for tilting and returning said chair to horizontal position and raising and lowering said housing with respect to the chair, and carrying said housing to the rear of said chair and returning to ambulatory position beneath said chair.

12. Stair climbing means as defined in claim 1 having a chair member, a frame beneath said chair member, means pivotally securing said seat to said frame member, and means for tilting said seat angularly backward upon said pivot and frame member.

13. The wheelchair defined in claim 1 wherein the com- 18 bination further includes means for locking said chair alternately in horizontal and tilted positions.

14. The wheelchair as denfied in claim 1 further including means for raising and lowering said housing beneath said seat.

15. Wheelchair as defined in claim 1 having a supporting frame therebeneath and having a housing fastened beneath said frame, means for raising and lowering said housing beneath said chair, said housing including means for stably supporting said seat in horizontal position, wheels pivotally secured to said chair supporting both the chair and housing above the horizontal level for horizontal ambulatory movement of the housing and chair, and means for pivotally folding said wheel out of groundengaging position when the chair is tilted to angular position on said supporting frame.

16. The wheelchair as defined in claim 1 further including means for sliding said housing directly to the rear of said chair and returning the housing for support beneath said seat, and means for raising and lowering said housing beneath said chair.

References Cited UNITED STATES PATENTS 468,022 2/1892 Bray 2805.28 2,751,027 6/1956 McLaughlin l9.l 3,142,351 7/1964 Green -8 3,227,465 1/1966 Massle 2805.2

LEO FRIAGLIA, Primary Examiner.

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