US3064744A - Self-propelled wheel chair - Google Patents

Description

5 Sheets-Sheet l Filed July ll, 1960 INVENTOR. #4i/@V62 JENA/W65 u?! @Mw NOV 20, 1962 H. c. JENNlNGs 3,064,744

SELF-PROPELLED WHEEL CHAIR Nov. ZO, 1962 H. c. JENNINGS 3,064,744

SELF-PROPELLED WHEEL CHAIR Filed July ll, 1960 3 Sheets-Sheet 3 Iillll IIIIIIIIIII J JNVENTOR. 5 7 #469V c. ./EA/A//A/@s 5 56 BY www@ nited States @t `lennings, Inc., Los Angeles, Calif., a corporation of California Filed July llll, 196i), Ser. No. 41,988 2 Claims. (Cl. Mil-6.5)

This invention relates to improvements in self-propelled invalid wheel chairs.

A primary object of the invention is to provide a wheel chair which has two separate electric motor drives, one for each drive wheel of the chair and arranged in a novel manner adjacent each side frame of the chair so that when the storage batteries and supporting frame therefor are removed from the chair the drives for the drive wheels will be so located -as not to interfere with the collapse of the chair which will enable it to be readily transported or stored in a relatively small space.

Another object of the invention is to provide an invalid wheel chair having two separate, reversible electric motor drives enabling either drive wheel to be driven forwardly or rearwardly independently of each other. Such a drive is necessary to enable the chair to be driven forwardly or rearwardly, or by driving one wheel forwardly while the other wheel is driven rearwardly, to effect a turning of the chair. Such motor drives frequently will not drive the drive wheels forwardly or rearwardly in perfect synchronism with each other. Consequently, if the chair is being propelled forwardly and one drive Wheel is being driven slightly faster than the other, the chair will tend to deviate from a straightforward path.

With the foregoing and other objects in view, which will be made manifest in the following detailed description and specifically pointed out in the appended claims, reference is had to the accompanying drawings for 4an illustrative embodiment of the invention, wherein:

FIGURE l is a rear view in elevation of the invalid wheel chair emboding the present invention;

FG. 2 is a front view in elevation of the same;

FIG. 3 is a side view in elevation of the same;

FIG. 4 is a partial view in vertical section taken substantially upon the line 4 4 upon FIG. 2 in the direction indicated;

FIG. 5 is a partial view in vertical section taken substantially upon the line 5 5 upon FIG. 2;

FIG. 6 is a partial view in horizontal section taken substantially upon the line 6 6 upon FIG. 3; and

FIG. 7 is a partial view taken substantially upon the line 7 7 upon FIG. 2.

Referring to the accompanying drawings wherein similar reference characters designate similar parts throughout, the improved invalid wheel chair consists essentially of two opposed side frames generally indicated at 10 and 11. Each side frame has a rear leg 12 extending upwardly and providing sides 13 for a rbackrest which sides terminates in handles 14 by which the chair can be manually propelled by a person other than an invalid.

At the bottoms of the rear legs 12 there are bottom members 15, the forward ends of which have extensions welded thereto which are bent upwardly as at 16 and which are connected to front legs 17. The upper ends of the front legs are rigidly connected to the rear legs by horizontal members 1S.

Portions of the bottom members have knuckles 19 rotatably mounted thereon to which the lower ends of X-brace members 2li are rigidly secured. These X-brace members are pivotally connected to each other by a pivot bolt 21. Their upper ends are rigidly secured to seat rails 22, the forward ends of which have ttings 23 pivotally mounted thereon that carry portions 24 that arent C telescope downwardly within the front legs 17. The rear ends of the seat rails have pivotally mounted thereon claws which slide upwardly on the rear legs 13.

A flexible seat 25 connects the seat rails and in a similar manner, a flexible backrest 26 connects the rear legs 13. On the outer sides of the side frames there are sockets 27 rigidly secured thereto which receive the lower ends of armrest supports 28 supporting armrests 29.

The above-described construction conforms particularly to one design of wheel chair which can be collapsed by merely pushing the side frames lil and 11 towards each other. During such movement of the side frames towards each other the members 20 of the X-brace merely pivot on their pivot bolt 2l and the seat rails 22 rise with respect to the side frames, such movement being permitted by the rotatable connection between the ttings 23 and the forward ends of the seat rails and the rotatable connections between the claws at the rear ends of the seat rails. When the seat rails rise the portions 24 merely rise partially from within the front legs 17 and the claws at the rear ends of the seat rails merely slide upwardly on the rear legs 13.

The swinging movements of the lower ends of the X-brace members 2li with respect to the bottom member l5 is afforded by the rotatable connection between the sleeves 19 with their respective bottom members.

At the rear ends of the side frames lll and 11 there are rigidly secured axle housings 30 that serve to mount axles for independently rotatable drive wheels 31 and 32. Similarly, at the lower ends of the front leg 17 there are rigidly mounted housings 33 for the spindles of forks 34 of caster wheels 35, it being understood that the spindles for the forks 34 enable the forks and caster wheels to be turned relatively to the side frames 10 and 11 in any required direction.

Each drive wheel has rigidly secured thereto such as by brackets 36 a drive rim 37 around which is trained an endless belt 38. Each belt 38 is also trained around a drive pulley 39 that is rotatably mounted on the housing for a reversible electric motor 40. The housing for each electric motor is pivotally mounted as at 41 so as to be suspended from the top member 18 of its respective side frame. Each belt 38 is also trained around a tightener pulley `42 that is rotatably mounted as at 43 on a link 44 that is pivotally mounted as at 45 on the motor housing 40. A link 46 is pivotally mounted as at 47 to each rear leg 12 of the side frames and is pivotally connected as at 48 to the rear end of its respective link 44. A handle 49 is rigidly mounted on each link 46 and has a twisted portion engageable with ratchet teeth 50 on a bracket 51 that is rigidly secured to each top member 18 of the side frames. Thus, by moving the handle 49 forwardly or rearwardly on disengaging the ratchet teeth the links 44 and 46 can be caused to assume positions of greater angularity with respect to each other than as shown in FIG. 4, or more nearly approaching positions in alignment with each other. The closer that these links are in alignment with each other causes the tightener pulley 42 to tighten the belt 38 to a greater extent. Conversely, if the angular relationship between the links 44 and 46 is greater than that illustrated the elfect of the tightener pulley on the belt 38 is to loosen it. The change in position of the links 44 and 46 is permissible by the motor housing 40 merely pivoting at 41 on its side frame. The reversible motors within the motor housings 40 are supplied with electric current from one or more storage batteries 52 which are supported on a storage battery holder 53 that rests on the side frames 16 and 11 between the rear legs 13. 'These storage batteries are electrically connected through a control box 54 that is mounted on one of the side frames and the control box in turn is electrically connected to a steering control box 55 mounted on one of the side frames.

The steering control box has a handle 56 that is mounted for universal movement in the box and is engageable with four contacts therein. Forward tilting of the handle 56 causes both electric motors to be energized to drive both drive Wheels forwardly. Conversely, rearward tilting of the handle 56 causes both motors to be reversely driven and to drive both drive wheels reawardly. If the handle 56 is tilted toward the left the motor driving the right-hand drive wheel is driven forwardly but the motor driving the left-hand drive wheel is driven rearwardly thus causing the wheel chair to be turned to the left. The converse situation exists when the handle 56 is tilted toward the right.

It frequently is very difficult to have both motors drive their respective drive wheels at exactly the same speed particularly when belt drives are employed Such as those illustrated. If one drive wheel is driven slightly faster than the other the wheel chair will tend to deviate from a straight path. To overcome this the forks 34 on the caster wheels are equipped with flanges 57 in which there are apertures 58, see FIG. 5, engageable by detents 59 that are urged downwardly by the compression springs 60. The compression of the compression springs can be adjusted by threaded adjusting bolts 61. These detents are located in housings 62 on the forward sides of the spindle housings 33. The apertures 58 are so located on the flanges 57 that when they are engaged by the detents 59 the forks 34 of the caster wheels 35 direct the caster wheels in a straight-forward direction. When the caster wheels are held in this direction they will cause the wheel chair to proceed in a straight-forward direction regardless of the fact that either drive wheel may be urged to rotate a little faster or a little slower than the other drive wheel.

When the handle 56 is tilted either to the right or to the left causing the drive wheels to be reversely driven the effort exerted thereby towards turning the wheel chair is sufficient to cause the caste-r wheels to turn their flanges 57 and cam the detents S9 out of the apertures 58. Once that the detents 59 are cammed out of their apertures the caster wheels 35 are then free to turn in any direction required. However, whenever the turn has been completed and the wheel chair is returned into a straight-forward direction the detents 59 will return to their positions in the apertures 58 and thus releasably hold the caster wheels in positions that will require the Wheel chair to proceed in a straight-forward direction. It will be observed that in this arrangement that each deter1t59 will offer a considerable resistance to an initial departure of caster wheels I from their straight ahead positions, but that after the detent is cammed out of the aperture 58, that the detent can then slide rather freely on the flange 57. Consequently, if there is any effort to return a caster wheel toward its straight ahead position this can be rather easily accomplished until the detent 59 snaps into its aperture 58. It is usually undesirable to have a caster wheel urged to return to its straight ahead position with greater effort the farther that it is turned from the straight ahead position. It is more desirable to have the greatest effort required to make the initial departure from a straight ahead position, and after such departure has been made, to have further turning of the caster Wheel accomplished quite easily.

A feature of the invention concerns the footrests. On the forward legs 17 of the side frames there are vertically aligned upstanding pins 63 and 64. The footrests supports which support the footrests 66 have ears 67 and 68 mounted thereon which are receivable over the pins 63 and 64, respectively. The tops of the footrests supports 65 are shaped to t against the forward sides of the front legs 17. The ears 68 also extend around the forward sides of the front legs 17 and are equipped with inclined camming surfaces 69, see FIG. 7. Near these camming surfaces the ears are provided with apertures adapted to partially receive spring urged detents 70 that 4 are vertically slidable in housings 71 and which can be lifted by handles 72. When a handle 72 is lifted to disengage the detent 70 from the ear 68, its footrest supports and footrest 66 can then be swung outwardly about the pins 63 and 64 as centers. When both footrests supports are swung outwardly the front of the wheel chair is left open and unobstructed by the footrests so that the wheel chair can be driven up close to tables and the like.

Whenever it is desired to return the footrests to their normal positions forwardly of the wheel chair, it is merely necesssary to swing the footrests supports 65 inwardly or towards each other. In the course of this swinging movement the camming surface 69 on the ear 68 engages the detent and cams it upwardly until the footrests support has reached its position extending forwardly of the front leg. In that position the detent 70 which is springactuated is automatically snapped into its aperture in the ear 63 releasably locking the footrest in its normal position.

One important feature of the invention resides in the nature of the belts 38, the drive rims 37 and the drive pulleys 39. The drive pulleys 39 are in the nature of V pulleys and the drive belts 38 are V belts designed to fit the drive pulleys 39. However, the rims 37 on the drive wheels are in the form of flat pulleys. If the rims 37 are made of V-shaped form to tit and accommodate the V belt 3S it becomes almost impossible to push the chair manually even though the belts may be in the Slack positions. Under these circumstances, the V belts tend to grab in the V of the rim even though they are slack. If the rims 37 are in the form of fiat pulleys the bottoms of the V belts slide easily relatively thereto in the slack position even though they are passing around a large flat rim.

When the idler 42 is tightened by manipulation of the handle 49 it moves up between the driven rim 37 and the drive pulley 39 tending to produce a greater wrap-around of the belt around both the drive pulley 39 and the rim 37. The greater wrap-around of these pulleys that it is pos sible to obtain allows less tension to be exerted on the V belt 33. Thus, the idler functions not only as a clutch to tighten the V belt but on being tightened tends to produce greater wrap-around each pulley. It also serves as a brake when the chair is not in motion because of the gear reduction in the drive between the motor and the drive pulley 39. The links 44, 46, and 49 are in a position to give a toggle effect with great mechanical advantage in moving the idler 42 into belt-tightening position.

From the above-described construction it will be appreciated that an improved self-propelled invalid wheel chair has been provided having many novel advantages. Whenever it is desired to collapse the wheel chair the battery support 53 and the batteries must be disconnected and removed. However, when the batteries and the battery support are removed the arrangement of the motors and their motor housings 40 and the belt drives to the drive wheels is such that the wheel chair can be collapsed in the usual manner. This is due to the fact that the motors and the drives are located within the planes of the side frames or substantially so.

Although one drive wheel may be urged to rotate faster or slower than its companion drive wheel, nevertheless by means of the detents 59 the caster wheels can be kept headed in a straight-forward direction until such time as it is desired to make an intentional turn. When this is desired proper manipulation of the handle 56 will cause the drive wheels to urge the chair to turn with sufficient effort to cam the detents 59 out of their apertures S8 and thus allow the wheel chair to be turned. The drive construction does not prevent the use of footrests which can optionally be swung outward or returned to their normal positions extending forwardly of the front legs and releasably locked therein.

Various changes may be made in the details of construction without departing from the spirit and scope of the invention as defined by the appended claims.

I claim:

1. A self-propelled invalid wheel chair having two opposed side frames, drive wheels and caster wheels rotatably mounted on said side frames, a drive rirn rigid with each drive wheel, an electric motor swingably mounted on each side frame having associated therewith a drive pulley driven thereby, a pair of links for each side frame, one link of each pair being pivotally connected to the other link of each pair, one link of each pair being pivotally connected to the rnotor on its side frame and the other tween the links of each pair, an idler pulley mounted for j rotation on one of the links of each pair, and endless belts trained over the drive rims, drive pulleys, and idler pulleys.

2. A self-propelled invalid wheel chair having two opposed side frames, drive wheels and caster wheels rotatably mounted on said side frames, a drive rim rigid with each drive Wheel, an electric motor swingably mounted on each side frame having associated therewith a drive pulley driven thereby, a pair of links for each side frame, one link of each pair being pivotally connected to the other link of each pair, one link of each pair being pivotally connected to the motor on its side frame and the other link of each pair being pivotally connected to its side frame, a handle rigid with one of the links of each pair by which the angular relationship between the links of each pair may be varied, means for releasably holding the handle in adjusted position, an idler pulley mounted for rotation on one of the links of each pair, and endless belts trained over the drive rims, drive pulleys, and idler pulleys.

ieei'ences Cited in the tile of this patent UNITED STATES PATENTS l 641,514 Hunt Ian. 16, 190() 2,272,981 Nelson Feb. 10i, 1942 2,456,088 Scircle Dec. 14, 1948 2,474,085 Albright I une 21, 1949 2,567,065 Ginsterblum Sept. 4, 1951 2,592,449 Miller Apr. 8, 1952 2,798,565 Rosenthal et al. July 9, 1957 2,862,569 Strunk Dec. 2, 1958

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