Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61G—TRANSPORT, PERSONAL CONVEYANCES OR ACCOMMODATION SPECIALLY ADAPTED FOR PATIENTS OR DISABLED PERSONS; OPERATING TABLES OR CHAIRS; CHAIRS FOR DENTISTRY; FUNERAL DEVICES
  • A61G5/00—Chairs or personal conveyances specially adapted for patients or disabled persons, e.g. wheelchairs
  • A61G5/10—Parts, details or accessories
  • A61G5/1056—Arrangements for adjusting the seat
  • A61G5/1059—Arrangements for adjusting the seat adjusting the height of the seat
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61G—TRANSPORT, PERSONAL CONVEYANCES OR ACCOMMODATION SPECIALLY ADAPTED FOR PATIENTS OR DISABLED PERSONS; OPERATING TABLES OR CHAIRS; CHAIRS FOR DENTISTRY; FUNERAL DEVICES
  • A61G5/00—Chairs or personal conveyances specially adapted for patients or disabled persons, e.g. wheelchairs
  • A61G5/04—Chairs or personal conveyances specially adapted for patients or disabled persons, e.g. wheelchairs motor-driven
  • A61G5/041—Chairs or personal conveyances specially adapted for patients or disabled persons, e.g. wheelchairs motor-driven having a specific drive-type
  • A61G5/046—Chairs or personal conveyances specially adapted for patients or disabled persons, e.g. wheelchairs motor-driven having a specific drive-type at least three driven wheels
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61G—TRANSPORT, PERSONAL CONVEYANCES OR ACCOMMODATION SPECIALLY ADAPTED FOR PATIENTS OR DISABLED PERSONS; OPERATING TABLES OR CHAIRS; CHAIRS FOR DENTISTRY; FUNERAL DEVICES
  • A61G5/00—Chairs or personal conveyances specially adapted for patients or disabled persons, e.g. wheelchairs
  • A61G5/10—Parts, details or accessories
  • A61G5/1051—Arrangements for steering
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61G—TRANSPORT, PERSONAL CONVEYANCES OR ACCOMMODATION SPECIALLY ADAPTED FOR PATIENTS OR DISABLED PERSONS; OPERATING TABLES OR CHAIRS; CHAIRS FOR DENTISTRY; FUNERAL DEVICES
  • A61G2203/00—General characteristics of devices
  • A61G2203/10—General characteristics of devices characterised by specific control means, e.g. for adjustment or steering
  • A61G2203/14—Joysticks
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61G—TRANSPORT, PERSONAL CONVEYANCES OR ACCOMMODATION SPECIALLY ADAPTED FOR PATIENTS OR DISABLED PERSONS; OPERATING TABLES OR CHAIRS; CHAIRS FOR DENTISTRY; FUNERAL DEVICES
  • A61G5/00—Chairs or personal conveyances specially adapted for patients or disabled persons, e.g. wheelchairs
  • A61G5/06—Chairs or personal conveyances specially adapted for patients or disabled persons, e.g. wheelchairs with obstacle mounting facilities, e.g. for climbing stairs, kerbs or steps

Definitions

• the invention relates to self-propelled steering wheelchairs designed for use in the domestic environment by disabled persons, characterised by being very compact in plan view, by a small steering radius and by the fact that it can be adjusted up and down to allow the disabled person to move with sufficient freedom and convenience in an environment of normal composition.
• the wheelchairs referred to are of the type which comprises a base structure of basically rectangular plan view, with bevelled corner regions and oriented so that the major dimension is longitudinal, and which at present stands on the ground via four small-diameter caster wheels arranged in the corner regions of this structure and with two rubber-tyred wheels of larger diameter mounted at the ends of a leaf spring.
• This spring is positioned along the longitudinal centre axis of the base structure and pivoted to it at an intermediate point of the spring on a transverse central axis, so that these wheels are both in permanent contact with the ground, even if there are small upward or downward irregularities in the ground.
• These larger-diameter wheels are both powered for forward or reverse travel and both have servo-controlled steering, in the sense that they are designed to steer simultaneously and in opposite directions to allow the wheelchair to pivot on itself if required.
• the use of small-diameter caster wheels causes serious problems in overcoming even small obstacles and the casters rapidly damage delicate floors such as those with a covering of wood or synthetic materials.
• the number of caster wheels is reduced to two and these wheels are located in the centre line or preferably slightly forward of the centre line of the side members of the base frame which thus has only four wheels of large diameter: two casters at the sides, as stated earlier, and two central driving and steering wheels which have themselves however also been modified in the following manner.
• driving wheels of known type mounted on the ends of the leaf spring which is pivoted at an intermediate point to the carriage frame, bore on the ground only by the pressure provided by the elasticity of the leaf spring and not by the weight of the user sitting on the chair.
• Fig. 1 is a diagrammatic side view of the wheelchair in the low position for travelling over the floor;
• Fig. 2 is a perspective view from one side of the carriage base of the wheelchair; - Figs. 3 and 4 illustrate other details of the carriage base depicted in
• Fig. 5 illustrates in part by a block diagram the electrical circuit controlling the wheelchair
• - Fig. 6 is a perspective rear view of the wheelchair highlighting the wheelchair lifting and lowering means
• Fig. 7 is a diagrammatic end elevation of the other details of the lifting and lowering means of Figure 6.
• the reference number 1 denotes the carriage frame, the plan view of which is basically rectangular, with the corner regions suitably bevelled.
• Fixed to the rear cross member 101 is a straight guide 2 that extends upwards and slightly backwards and on which a runner 3 carrying the chair P, with its arms, on which the disabled person sits can be caused to travel by means of a servocontrol that will be described later.
• the frame 1 is usually designed to hold a single rechargeable electric battery, its size being calculated to keep the wheelchair running for a specified number of hours, which are those of normal usage of the wheelchair in the course of one day.
• the battery could be designed with a capacity such as to ensure a small reserve of operation beyond the officially stated time, and yet sometimes this reserve might not be sufficient.
• the battery would be connected up to the recharger while still partially charged and could therefore experience incomplete recharging because of the known effects of polarization of its electrodes.
• a longitudinal housing 4 is formed on the centre line of the frame 1 : it consists for example of longitudinal sections 104 of flat type and L-section crosspieces 204 and is able to hold two rechargeable electric batteries A, A' having identical characteristics, preferably chosen to have a single capacity such that one battery discharges completely at or even before the end of the normal daily use of the wheelchair. From the diagram shown in Figure 5, it can be seen that the batteries A, A' are connected by their positive poles to a switch 5 whose common 105 is connected to two electronic boards 6 and 106. Board 6 controls the operation of the various electric traction and steering motors M of the chair (see later) through the joystick 7 on one of the arms of the chair.
• Board 106 controls, via controls 122 also on an arm of the chair, the operation of the electric seat-moving motors M'.
• the common 105 of the switch 5 is also connected to the outlet of a battery charger 8 which, via an on-off switch 9 and a plug 10 can be connected to the household mains supply when recharging the batteries.
• Means (not illustrated) are provided so that, by selecting the recharging function via the on-off switch 9, all the functions of the chair are automatically disabled.
• the negative poles of the batteries are connected to the negative pole of the boards 6, 106.
• the chair is supplied by only one of the two batteries A or A', and towards the end of the day, if the chair is used normally, it is expected that this battery will have discharged and this condition, besides being indicated by a slowing down of the movements of the wheelchair, is notified by a warning device 11 , which may be optical, for example.
• a warning device 11 which may be optical, for example.
• the switch 5 to isolate the discharged battery and connect the charged battery to the boards 6, 106.
• the switch 5 At the end of the day, when the wheelchair is put away and the plug 10 connected to the mains, the user moves the switch 5 to the position it was not in, to connect the drained battery to the battery charger 8 and activates this component through the on- off switch 9.
• the user turns off the on-off switch 9, removes the plug 10 from the mains and operates the switch 5 to isolate the battery which was charged overnight and activate the battery that was used only temporarily on the previous day.
• FIGS. 1 to 4 and 6 show that the base frame 1 stands on the ground via four wheels only, preferably with rubber treads, all of large diameter and all the same as each other.
• two caster wheels 12 are mounted so as to rotate freely on vertical pins 112, slightly forwards of the centre line of the frame 1 , one on each side of the said frame.
• a third wheel 13 rotates about its own vertical pin 113 mounted on a bracket 201 located in the centre line of the rear face of the frame 1.
• a fourth wheel 14 is located centrally at the front of the frame 1 and rotates about a vertical pin 114 connected to the end of a leaf spring 15 which runs longitudinally along the centre line of the frame 1 and is welded to the intermediate crosspieces of the frame 4 and at the other end to the cross member 101 and/or to the neighbouring crosspiece 204 of the same frame 1 on which the batteries are carried.
• the free end of the leaf spring 15 is characterized by an upwardly concave profile, such that the spring does not normally touch the front crosspiece 204' of the frame 4 and, when the wheelchair is at rest, the wheel 14 is in the position indicated in Figure 4 at 14' in chain line, so that the chair contacts the ground through the wheels 14, 13 and through only one of the side wheels 12.
• Both wheels 13 and 14 are powered by respective motor/gearbox assemblies 16, 16' having identical characteristics and with d.c. electric motors M able to turn in both directions of rotation, connected to the board 6 of Figure 5 and flanged to the frames of these wheels, which at the top have lever arms 213, 214 of identical length, oriented one on the left-hand side and the other on the right-hand side of the frame 1.
• the motor/gearbox assembly 19 is flanged to a bridge 20 fixed beneath and in the intermediate part of the frame 4, as can be seen in Figures 2, 3 and 6, roughly where the leaf spring 15 is fixed at an intermediate point, so that the steering position of the wheel 14 does not vary when the spring 15 oscillates.
• the synchronous steering in opposite directions of the wheels 13 and 14 brought about by the motor/gearbox assembly 19 will allow the wheelchair to steer, if required, about itself and to move even in narrow spaces.
• suitable electronic and/or mechanical means are provided to limit the steering angle, so that the system of tie rods 17, 17' and levers 213, 214 do not pass dead centre.
• the leaf spring 15 is still not touching the crosspiece 204' at the front of the frame 4, so the user can lean his or her body forwards so that the wheelchair rocks on the side wheels 12, which act as fulcra, and lifts the rear wheel 13, which can thus easily surmount the obstacle, assisted by its own rotation and by the traction of the front driving wheel 14.
• either or both of the driving and steering wheels 13 and/or 14 may be double wheels or may be replaced by pairs of wheels whose steering movements are synchronized.
• servocontrols have been used for the movement of the runner 3, so that these conditions can also be reached.
• Figures 6 and 7 show that the guide 2 is a portal frame and that the channel-section sides of the runner 3 slide, with intermediate inserts of a suitable plastic material, up and down its uprights.
• a plate 21 At the bottom of the guide 2, fixed to its uprights, is a plate 21 to which is flanged a motor/gearbox assembly 22 with a d.c. electric motor M' able to turn in both directions of rotation, the slow shaft of which passes through a hole in the said plate 21 and is secured to a small-diameter sprocket 23.
• the motor M' of the motor/gearbox assembly 22 is operated via the control 122 located on one of the arms of the wheelchair and connected to the board 106, Figure 5.
• a downward bracket 124 Fixed to the top member of the guide 2 is a downward bracket 124 to which is rotatably attached a sprocket 24 larger than the drive sprocket 23, and at least one robust chain 25 passes around these sprockets and is connected by its ends to a bracket 26 integral with the runner 3 so that as the motor/gearbox assembly 22 rotates in one direction or the other, the chair rises or falls.
• the gearbox of the assembly 22, like those of assemblies 16, 16' and 19, is of irreversible type, e.g. is a worm and helical wheel.
• the plate 21 carry a small casing 27 equipped with a collar 127 circumscribing that part of the sprocket 23 which carries the chain 25. It has divergent ends 127 and supports a small integral shoe 227 that acts on the inside of the said chain run, so as to orient it correctly, even if slack, as it meshes with the drive sprocket 23.
• the chain run extending between the sprockets 23, 24, which is continuous, is enclosed in a tubular guide of polygonal section 28 mounted on the adjacent upright of the guide 2, e.g. by means of brackets 128, and the pin of a shoe 29 of e.g. plastic is inserted into one of the links of this chain run.
• This shoe 29 has bevelled front and rear edges and is guided as it travels inside the said guide 28.
• Openings are provided in the wall of the guide 28 on which the shoe 29 runs, to house the terminals of microcontacts 30, 30' which stop the movement of the chair at the top of its lifting travel and at the end of the maximum descent travel respectively, while an intermediate microcontact 30" operated for example by the runner 3 or by parts attached to this runner, enables horizontal movement of the vehicle only if the chair P is close enough to the frame 1 to ensure the stability and safety of the said horizontal movement.
• the electric cables 31 connecting the lower actuators on the frame 1 to the controls on the arms of the chair, only one of which is visible in Figure 6, are of spiral type: a cylindrical helical spring 32 passes through the middle of each, the top end 132 being fixed to the runner 3, together with a length of the cable 31 , while the bottom end is fixed at 232 to the fixed plate 21 , together with a corresponding point of the said cable 31 , all of this being done in such a way that the cable can lengthen and shorten while being guided by the spring and without interfering with the relatively moving parts of the wheelchair which will be equipped with appropriate protective casings having both safety functions and aesthetic functions, though these have not been illustrated as they are not necessary to an understanding of the invention.
• the present wheelchair is also equipped at the front and underneath the seat with a known parallel-motion structure 33 supporting at the front a footrest 133 which can be adjustably extended and which, when the chair is fully down, rests via its own component 233 on the frame 1 to keep the said footrest a suitable distance from the ground.
• the structure 33 is hooked to the wheelchair by a chain which ensures the correct downward extension of the jointed structure 33 when the chair is raised.
• the invention dispenses with this chain, which can restrict the user's movements, and replaces it with an adjustable screw 34 attached for example to the upper link of the parallelogram 33 and extending towards the opposite link so as to touch the nearest of the vertical sides of the parallelogram when the chair is up and the links are inclined downwards. This will be obvious to, and is easily carried out by, those skilled in the art.

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• Health & Medical Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Animal Behavior & Ethology (AREA)
• General Health & Medical Sciences (AREA)
• Public Health (AREA)
• Veterinary Medicine (AREA)
• Handcart (AREA)

Applications Claiming Priority (3)

Publications (1)

Family

ID=32375517

Family Applications (1)

Country Status (3)

Families Citing this family (4)

Family Cites Families (3)

• 2002
  • 2002-11-25 IT IT000121U patent/ITBO20020121U1/it unknown
• 2003
  • 2003-10-24 WO PCT/EP2003/011806 patent/WO2004047709A1/en not_active Ceased
  • 2003-10-24 EP EP03769448A patent/EP1496828A1/de not_active Withdrawn

Non-Patent Citations (1)

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