FR2615100A1 - Manual tracked wheelchair with gear reduction system for climbing and descending staircases - Google Patents

Abstract

The invention relates to a device making it possible to climb staircases using the power of the muscles of the upper limbs. It consists of a torque gear reduction system. The user pulls on the handrails 1 and 1', thus transmitting to the wheels 4 and 4', connected to the wheels 5 and 5' by two tracks fitted with spikes, an adequate torque. Transmission is provided by two gears 2 and 3 and a belt 8. For descent, the wheelchair is controlled using the handrails 6 and 6', this phase, in contrast to the preceding one, being preformed in forwards motion. The wheels 5 and 5' are fitted with ratchet wheels. The left wheel is locked for turning left and the right wheel for turning right.

Description

MANUAL TRACKED WHEELCHAIR WITH SYSTEM
DEMULTIPLICATION FOR GOING UP AND DOWN FROM STAIRS
The present invention relates to a wheelchair intended to allow a paraplegic handicapped person (having a full muscular capacity of the upper limbs) to ascend and descend staircases, sidewalks and slopes Up to 350 inclination with respect to the horizontal.

 There are armchairs of identical use but all are electric, hence a limited autonomy and a weight of the order of 90 kilograms.

 The device according to the invention makes it possible to remedy these drawbacks. In fact, it includes a reduction in the forces produced by the user, thus obtaining sufficient torque to allow the obstacles described above to be crossed.

 Initially, the invention will be described according to its operating principle, the technological details will be repeated later.

 Figure I shows in schematic form and in perspective, the device according to the invention.

 Figure 2 shows in schematic form, the device according to the invention.

 Thanks to the handrails (I) and (I ') the user transmits to the large wheels (4) and (4'), via the pinions (2) and (3) and a belt (8), enough torque to climb stairs.

 The wheels (4) and (5), (4 ') and (5') are connected by two internal belts (7) and (7 ') equipped with external crampons capable of hanging on the steps.

 The ascent takes place in reverse, the wheels (4) and (4 ') are mounted on free wheels with reverse locking thus coupling with the shaft carrying the pinion (3).

 The wheels (5) and (5 '), mounted free, are fitted with a disengageable ratchet wheel system allowing the wheelchair to be locked when, during the ascent phase, the user releases the handrails (I) and (I ').

 For the descent which takes place in forward gear, the wheelchair is controlled using the handrails (6) and (6 ') secured to the large wheels (4) and (4').

 Each time an obstacle is crossed, the seat is kept in a horizontal position by means of a tilting system.

 In normal operation, the user moves the chair using the handrails (6) and (6 '). To turn, the inner wheel is locked in the center of rotation and the user drives the other wheel forward. In other words, we block the left wheel to turn left and the right wheel to turn right.

 Now, the invention will be described in more detail with reference to the drawings.

 Figure 3 shows, from the side, the device according to the invention.

 Figure 4 shows, from behind, the device according to the invention.

 Figure 5 shows, in section, the torque reduction system.

 Figure 6 shows, in section, the mounting of the small front wheels.

 Figure 7 shows the ratchet and the ratchet wheel.

 Figure 8 shows the ratchet control.

 Figure 9 shows, in section, the track tensioner.

 FIG. 10 represents, in perspective, the chassis of the device according to the invention.

 The present device consists of a welded chassis (22).

It consists of two aluminum alloy side plates, reinforced by profiles and connected by a set of crosspieces. To limit the weight of the device, the side plates are hollowed out in certain places
Fig. IO.

 The present device consists of a reclining seat (9); in addition to the horizontal position, the seat can be tilted at 200 and 400, this allowing the user to remain in a horizontal position while crossing obstacles. The axis of rotation of the seat is fixed to the chassis.

The seat is indexed by a double lateral system consisting of a stud held in position by a return spring. Fig. 3 and 4.

 The present device consists of two large rear wheels (4) and (4 ') and two small front wheels (5) and (5').

 The large wheels have a stocky, zoidal notch on their periphery intended to drive the tracks (7) and (7 '): FIG. 3. The large wheels (4) and (4 ') are mounted on free wheels and on bearings - Fig. 5.

The wheels (4) and (4 ') have lateral flanges whose function is to prevent the tracks from "jumping" - Fig. 5.

 The small wheels (5) and (5 ') have an external notch identical to that of the wheels (4) and (4') - Fig. 3. The small wheels (s) and (5 ') are mounted free (on bearings) on the axle 21 - Fig. 6.

 Ratchet wheels (I5) and (I5 ') mounted integral with the wheels (5) and (5') - Fig. 6.

 A cable control (I6) acts on an intermediate piece (I7) integral with an axis (fus) on which are mounted, keyed, the two pawls (3I) and (32).

A return spring (I9) keeps the pawls in position on the ratchet wheels - Fig. 8. The wheels (s) and (5 ') are equipped with lateral flanges which prevent the tracks from dislodging
Fig. 6.

The axis (I8) is secured to the chassis by two pins (20) and (20 ')
The torque reduction system consists of handrails (I) and (I ') integral with the primary shaft (IO) on which the toothed pinion (2) is located. A toothed belt (8) connects the pinion (2) to the notched pinion (3), integral with the secondary shaft (If). Fig. 5. The reduction ratio between the pinion (2) and the pinion (3) is 5. A tensioner (I3) ensures the tension of the belt (8) but also the passage of the seat in an inclined position at 400 - Fig. 5.

 The primary axis (IO) is held in translation relative to the chassis thanks to the pins (I2). -The secondary axis (II) is held in translation relative to the chassis thanks to the pins (I4). The pinions (2) and (3) are keyed and held in translation by elastic rings on their respective shafts - Fig. 5.

 The tracks (7) 'and (7') - have a drive notch corresponding to that of the wheels (4), (4 ') and (5), (5'). On the outside, they also have a more pronounced notch, capable of hooking the stair treads - Fig. 3.

 Tensioners ensure better absorption of the steps, for a more flexible movement - Fig. 3. They consist of a roller (23) carried by an axis (26) bridged in a sheath at (27), the roller being kept in contact with the track by a return spring (28) - Fig. 9.

 A retractable stop (29) constitutes a safety device in the event of displacement of the center of gravity of the assembly. A tension spring (30) allows the stop, during the ascent phase, to retract the edges of the steps.

Claims (7)

 I.- Device for going up and down stairs, sidewalks and slopes at 350 relative to the horizontal, c ectérisd in that it includes a reduction in torque allowing the user to maneuver it thanks to the force muscle of its upper limbs. Thanks to the handrails (I) and (I '), the user transmits to the wheels (4) and (4'), via the toothed pinions (2) and (3) and a toothed belt (8 ), sufficient torque to climb stairs.  2.- Device according to claim I characterized in that the wheels (4) and (4 ') are mounted on free wheels allowing their locking relative to their shaft in the ascent phase.  3.- Device according to claim I or claim 2 characterized in that the wheels (5) and (5 '), mounted free, are equipped with disengageable ratchet wheels.  4.- Device according to any one of the preceding claims, characterized in that the wheels (4) and (4 ') are equipped with handrails (6) and (6').  5.- Device according to any one of the preceding claims, characterized in that the wheels (4) and (5), (4 ') and (5') are equipped with a track having an internal notching as well as a set of spikes exteriors capable of hanging on the steps.  6.- Device according to any one of the preceding claims, characterized in that a tilting system with several positions allows the seat to be kept horizontal.  7.- Device according to any one of the preceding claims characterized in that the mechanically welded frame consists of two side plates of aluminum alloy reinforced by profiles and connected by crosspieces.