Wheelchair having manual drive and brake
Patent Information
- Application Number
- PCT/EP2026/060835
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2025-04-17
- Filing Date
- 2026-04-15
- Publication Date
- 2026-10-22
Smart Images
Figure EP2026060835_22102026_PF_FP_ABST
Abstract
Description
[0001] Wheelchair with manual drive and brake
[0002] The invention relates to a wheelchair comprising:
[0003] a seating area;
[0004] a first wheel and a second wheel, the first and second wheels being arranged on opposite sides of the seat; and
[0005] a first manual wheel drive for driving the first wheel and a second manual wheel drive for driving the second wheel, wherein the first and the second manual wheel drive each have an actuating lever and the first manual wheel drive is coupled to the first wheel via a first power transmission unit and the second manual wheel drive is coupled to the second wheel via a second power transmission unit.
[0006] To protect the joints of wheelchair users and optimize the power transmission from the muscles to the wheelchair wheels, wheelchairs with joint-friendly manual wheel drives are known from current technology. These utilize lever or crank mechanisms to indirectly drive the wheelchair wheels, thereby also enabling power transmission. Compared to direct manual propulsion via handrims, these mechanisms offer more ergonomic, joint-friendly, and efficient wheelchair movement.
[0007] A wheelchair with a crank mechanism is known from the prior art, for example, from US 6,910,701 B1. In this wheelchair, the rotary motion of two cranks on opposite sides of the wheelchair is transmitted to the wheels by means of belts or chains. This makes it possible for a wheelchair user to propel the wheelchair without using handrims on the wheels.
[0008] EP 3 823 576 Bl discloses a wheelchair with two mechanical wheelchair drives on opposite sides of the wheelchair, which are also coupled to the wheelchair wheels via belts or other means. Each wheelchair drive has a length-adjustable lever mounted on a guide plate. A non-circular guide is integrated into the guide plate, which causes the length of the lever to change during rotation. The shape of the guide can be optimized to minimize stress on the joints and muscles while simultaneously maximizing the mechanical power transmitted to the wheelchair wheels.
[0009] A disadvantage of conventional wheelchairs with lever and crank mechanisms is that they require separate and independent braking systems to ensure safe braking. For this purpose, corresponding brake levers are attached to the handles of the lever and crank mechanisms, connected to brake units on the wheels, such as disc or drum brakes, via hydraulic or wire lines. However, these hydraulic or wire lines can be a nuisance for the user when propelling the wheelchair, as they can protrude from the levers or cranks and become entangled in clothing, the wheelchair itself, or surrounding objects. Furthermore, the constant twisting or pivoting motion during wheelchair propulsion can cause the hydraulic or wire lines to wear out quickly and eventually fail.Another disadvantage is the high level of design effort required to guide the hydraulic or wire lines around moving parts, such as levers or cranks.
[0010] Another disadvantage of known wheelchairs with lever and crank mechanisms is that turning the wheelchair in tight radii, or even turning it on the spot around a vertical axis, is very difficult or impossible. With these prior art wheelchairs, the user must use any handrims on the wheels to enable turning on the spot, or brake on one side and propel the wheelchair on the other to at least be able to navigate a relatively tight turning radius, if turning on the spot is not possible. Therefore, wheelchairs with lever or crank mechanisms are rather unsuitable for confined indoor spaces. Further wheelchairs with lever and crank mechanisms are known from WO 2006 / 062643 A2 and US 2025 / 0073102 A1. US 11,730,644 B2 discloses a wheelchair with a handrim for driving the wheelchair wheels in both directions and for braking.
[0011] EP 0 136 705 Bl describes a gearbox for muscle-powered vehicles.
[0012] In light of the above, the object of the present invention is to mitigate or even completely eliminate the disadvantages of the prior art. Preferably, the object of the present invention is to provide a wheelchair of the type mentioned above that allows turning on the spot and simplifies braking.
[0013] This problem is solved by a wheelchair with the features of claim 1.
[0014] According to the invention, in a wheelchair of the type mentioned above, a first wheel hub unit is provided in or on a first wheel hub of the first wheel and a second wheel hub unit is provided in or on a second wheel hub of the second wheel, wherein the first and the second wheel hub units are designed to
[0015] - in a first position, a rotation of the first / second wheel by the first / second manual wheel drive in a forward direction,
[0016] - in a second position, a freewheel of the first / second wheel ,
[0017] - in a third position, braking of the first / second wheel and
[0018] - in a fourth position, a rotation of the first / second wheel by the first / second manual wheel drive in a reverse direction
[0019] to enable this. Advantageously, the wheelchair according to the invention allows not only forward movement but also braking and turning both or individual wheels in a reverse direction using the wheel drives. This eliminates not only separate braking systems with any hydraulic or wire lines at the operating levers, as required in wheelchairs of known type, but also makes it possible to turn the wheelchair essentially around a vertical axis in place by turning one wheel forward on one side and the other wheel backward on the other. Advantageously, the wheelchair according to the invention is therefore particularly well suited for indoor use. The first and second manual wheel drives can be essentially identical in design but mirrored relative to each other.The first and second manual wheel drives can preferably be mounted on a base frame of the wheelchair. The operating levers of the wheel drives are preferably rotatably mounted. Each operating lever can have a handle for gripping, which can be rotatably mounted on the respective operating lever, preferably at one end of the respective operating lever. The seat of the wheelchair is arranged between the manual wheel drives. A backrest can be attached to the seat. To rest the feet of a wheelchair user, at least one footrest can be provided, which can be attached to the base frame of the wheelchair. To stabilize the wheelchair, additional wheels, which can have a smaller diameter than the first and second wheels, can be provided. The additional wheels can, for example, be mounted on the at least one footrest or on the base frame.The additional wheels can be mounted in wheel suspensions that can be rotatably attached to at least one footrest or to the base frame about a vertical axis. The first and second power transmission units can each comprise, for example, a belt, a chain, a shaft, and / or a gearbox for power transmission between the first and second wheel drive, respectively, and the first and second wheel, respectively. A belt is preferred due to its lower weight and simpler guidance. One or more guide rollers can be provided to guide the belt. It is preferred if the first and second power transmission units are essentially identical, or at most mirrored. According to the invention, the first and second wheel hub units are arranged in or on the first and second wheel hubs, respectively. This results in a particularly compact design of the wheelchair.The first and second wheel hub units are essentially identical, but mirrored. Each wheel hub unit can be moved into a first, second, third, and fourth position. Preferably, the transition between positions is achieved by rotating the actuating levers of the first and second wheel drives, respectively, in the corresponding direction. For example, if the first wheel drive is rotated forward, the first wheel hub unit moves into the first position. If the first wheel drive, in particular its actuating lever, is held in position or moved slightly backward while the first wheel rotates forward, the first wheel hub unit moves into the second position. If the first wheel drive is rotated (further) backward, the first wheel hub unit moves into the third position.If the first wheel drive is rotated further in the reverse direction, the first wheel hub unit is moved into the fourth position. In the fourth position, the first wheel is rotated in the reverse direction. In the first position, a rotation of the actuating lever in the forward direction is preferably translated into a rotation of the first wheel in the forward direction. In the fourth position, a rotation of the actuating lever in the reverse direction is preferably translated into a rotation of the first wheel in the reverse direction. In other words, in both the first and fourth positions, the first wheel is driven by rotating the actuating lever of the first wheel drive. The positions of the first wheel hub unit can be achieved by moving an element within the first wheel hub unit. An analogous situation arises for the second wheel hub unit and the second wheel drive.The descriptions of the first wheel hub unit are therefore transferable to the second wheel hub unit. In the first position of the first wheel hub unit, rotation of the first wheel in the forward direction is possible. For this purpose, a frictional and / or positive locking connection can be established within the first wheel hub unit, which allows force and torque transmission from the first power transmission unit to the first wheel in the forward direction. In the second position, the frictional and / or positive locking connection can be released, so that essentially no force and torque transmission takes place between the first wheel and the first power transmission unit. The first wheel can rotate freely in the second position of the first wheel hub unit; a freewheel is present. In the third position, a further frictional and / or positive locking connection can be established, in particular by means of brake linings or...Friction elements are manufactured that generate a braking torque which is transmitted to the first wheel to reduce its speed. The friction and / or positive engagement and the further friction and / or positive engagement can be located at different points in the first wheel hub unit. In the fourth position, the further friction and / or positive engagement can be used to enable force and torque transmission from the first power transmission unit to the first wheel in the reverse direction. In one embodiment of the invention, the positions are arranged sequentially in the specified order. To change between the positions, they must be traversed in the specified order in this embodiment. Thus, to change from the first to the third position or vice versa, it is necessary to temporarily switch to the second position. The description also applies to the second wheel hub unit and the second wheel drive.The forward direction is opposite to the reverse direction. Preferably, the first and second wheel hub units are at least partially integrated into the first and second wheel hubs, respectively. In one embodiment of the invention, the first and / or the second wheel hub unit each have a coaster brake or can be formed by one. This allows the first and second wheel hub units to be easily moved into the first, second, third, and fourth positions.
[0020] Directional terms such as "up", "down", "forward" and "backward" refer to the intended use of the wheelchair.
[0021] It is advantageous if the first wheel hub unit has a first rotating part coupled to the first power transmission unit, and the second wheel hub unit has a second rotating part coupled to the second power transmission unit. The first and second rotating parts can be identical but mirror images of each other. For coupling with the power transmission units, it is advantageous if the first and second rotating parts are each coupled to a gear or have, in particular, a gear. The first rotating part can be supported by a first rotary bearing, in particular a ball bearing. The second rotating part can be supported by a second rotary bearing, in particular a ball bearing.
[0022] It is advantageous if
[0023] - the first turned part has a first thread, in particular an external thread, which engages with a mating thread, in particular an internal thread, of a displaceable first coupling element, wherein a rotation of the first turned part causes a displacement of the first coupling element within a first wheel hub housing,
[0024] - the second rotating part has a second thread, in particular an external thread, which engages with a mating thread, in particular an internal thread, of a displaceable second coupling element, wherein a rotation of the second rotating part causes a displacement of the second coupling element within a second wheel hub housing, wherein by displacing the first and the second coupling elements the first and second wheel hub units can be moved between the first, second, third and fourth positions. The first and the second coupling elements are preferably designed as sleeve elements which at least partially surround the first and the second rotating part, respectively. Preferably, the first and the second coupling elements have essentially the form of a hollow cylinder with a rounded outer surface. By rotating the first and the second coupling elements, the first and second coupling elements can be moved between the first and second positions by the interaction of the threads and corresponding mating threads.The second clutch part can be moved.
[0025] In one embodiment of the invention, the first and second coupling elements are each arranged in an end position when the first and second wheel hub units are in the first and fourth positions, respectively. The end positions refer to the displacement of the coupling element along an axis of the respective wheel hub unit. In the end positions, further displacement of the first and second coupling elements in one direction along the axis of the first or second wheel hub unit is blocked; only displacement in the opposite direction is possible. In the end positions, a positive and / or frictional engagement can exist between the first / second coupling element and an inner wall of the first / second wheel hub housing of the first / second wheel hub unit or an inner wall of the first / second wheel hub.The final position of the first and second coupling elements in the fourth position can also essentially correspond to the position of the first and second coupling elements in the third position.
[0026] To enable freewheeling, it is advantageous if the first and second coupling elements are each arranged in a central position when the first and second wheel hub units are in the second position. In the central position, the first / second coupling element can be decoupled from an inner wall of the first / second wheel hub housing of the first / second wheel hub unit or an inner wall of the first / second wheel hub, so that there is no frictional and / or positive engagement between the first / second coupling element and an inner wall of the first / second wheel hub housing of the first / second wheel hub unit or an inner wall of the first / second wheel hub.
[0027] To facilitate freewheeling, it is advantageous if the first wheel hub unit has a first spring that biases the first clutch element towards the center position when the first wheel hub unit is in the first position, and the second wheel hub unit has a second spring that biases the second clutch element towards the center position when the second wheel hub unit is in the first position. The first and second springs can, for example, be coil springs. The first spring can be arranged around an axis of the first wheel hub unit. The second spring can be arranged around an axis of the second wheel hub unit. To drive the first and second wheels in the forward and reverse directions, it can be advantageous if
[0028] - in the first, third and fourth positions of the first wheel hub unit, the first coupling element is frictionally and / or positively connected to an inner wall of the first wheel hub housing of the first wheel hub unit or to an inner wall of the first wheel hub, so that a rotary movement of the first manual wheel drive is transmitted to the first wheel; and in the first, third and fourth positions of the second wheel hub unit, the second coupling element is frictionally and / or positively connected to an inner wall of the second wheel hub housing or to an inner wall of the second wheel hub, so that a rotary movement of the second manual wheel drive is transmitted to the second wheel.
[0029] Particularly with regard to braking, it is advantageous if the first wheel hub unit has at least one first friction element and the second wheel hub unit has at least one second friction element, wherein the first friction element is in frictional contact with the first coupling element and the inner wall in the third and fourth positions of the first wheel hub unit, and wherein the second friction element is in frictional contact with the second coupling element and the inner wall in the third and fourth positions of the second wheel hub unit. The inner wall can be the inner wall of the respective wheel hub housing or the inner wall of the respective wheel hub. In the third and fourth positions, the first friction element is preferably arranged between the first coupling element and the inner wall of the first wheel hub housing or the first wheel hub.The second friction element is preferably arranged between the second coupling element and the inner wall of the second wheel hub housing or the second wheel hub in the third and fourth positions. By rotating the actuating lever of the respective wheel drive, the respective coupling element can be moved and brought into contact with the first or second friction element. By holding the first actuating lever of the first wheel drive in the third position of the first wheel hub unit, the first rotating wheel can be braked. By holding the second actuating lever of the second wheel drive in the third position of the second wheel hub unit, the second rotating wheel can be braked. The first and second friction elements can, for example, be formed by brake pads and made of steel.
[0030] In a preferred embodiment of the invention, the wheelchair may have the following features:
[0031] a first clutch which can be activated by a first actuating element, so that the actuating lever of the first wheel drive is decoupled from the first wheel, and / or
[0032] A second clutch, which can be activated by a second actuating element, so that the actuating lever of the second wheel drive is decoupled from the second wheel. The first and second clutches can each be independent of the first and second clutch elements. Preferably, the first and second clutches can each be independent clutches. The first and second clutches can, for example, be used to align the actuating levers of the first and second wheel drives in parallel, if necessary. The first and / or second clutches can thus form a kind of freewheel mechanism. This can be advantageous after braking or cornering. The first and second clutches can each have two clutch parts to decouple the actuating levers from the respective wheels, i.e., the first and / or second wheel.In the engaged state, the coupling components of a coupling transmit rotary movements of the actuating levers from one input side to one output side of the coupling. In the disengaged state, the coupling components are decoupled, so no rotary movements of the actuating levers are transmitted to the output side. In the disengaged state of the first coupling, it allows free rotation of the actuating lever of the first wheel drive. In the disengaged state of the second coupling, it allows free rotation of the actuating lever of the second wheel drive. The first and second couplings can be actuated by their respective actuating elements. The first and / or second coupling can be activated by their respective actuating elements, for example, hydraulically or mechanically, such as by cable or linkage.In another embodiment, the first and / or second coupling can be an electric coupling supplied with an electrical energy storage device and actuated by an actuator, for example, an electric motor or an inductive element. Such electric couplings are known from the prior art, so they will not be discussed in detail. In this case, the actuating element can be, for example, an electronic button or lever that sends an actuation signal wirelessly or via cable to the first or second coupling, which is then actuated.
[0033] It is therefore advantageous if the first actuating element is located on the first actuating lever of the first wheel drive and the second actuating element is located on the second actuating lever of the second wheel drive. The first and second actuating elements can be, for example, a button, a switch, or a lever.
[0034] To transmit torque from the first and second wheel drives to the first and second wheel hub units, respectively, it is advantageous for the first and second power transmission units to each have a transmission belt, a transmission chain, and / or a transmission gearbox. The first power transmission unit is mechanically coupled to the first wheel drive and to the first wheel hub unit. The second power transmission unit is mechanically coupled to the second wheel drive and to the second wheel hub unit. To guide a chain or transmission belt, the power transmission units can have pulleys. In one embodiment of the invention, transmission gearboxes can be provided in the power transmission units to translate torque. These gearboxes can also be switchable, allowing for the selection of multiple speed ratios. To transmit the torque, the first and second wheel hub units can be equipped with a transmission belt, a transmission chain, and / or a transmission gearbox.The second wheel hub unit, as well as the first and second wheel drives, may be equipped with chainrings, wheels, gears, or toothed belt pulleys. This is particularly advantageous when transmission chains or belts are used, as the chainrings, wheels, gears, or toothed belt pulleys can be operatively connected to them to transmit torque.For example, the actuating lever of the first wheel drive can preferably be non-rotatably connected to a chainring, wheel, gear, or toothed belt pulley, around which a transmission belt or chain of the first power transmission unit is at least partially wound, and the first wheel hub unit has a further chainring, wheel, gear, or toothed belt pulley, around which the transmission belt or chain is also at least partially wound, so that a torque can be transmitted from the actuating lever to the chainring, wheel, gear, or toothed belt pulley, subsequently to the transmission belt or chain, then to the further chainring, wheel, gear, or toothed belt pulley, and finally to the first wheel. The further chainring, wheel, gear, or toothed belt pulley can be non-rotatably connected to the first rotating part or be formed by it.The same applies to the second wheel drive, the second wheel hub unit and the second wheel.
[0035] In a preferred embodiment, the actuating lever of the first and second wheel drives is rotatably mounted, preferably rotatably through 360°. The first power transmission unit is designed to transmit a rotary movement of the actuating lever of the first wheel drive to the first wheel hub unit, and the second power transmission unit is designed to transmit a rotary movement of the actuating lever of the second wheel drive to the second wheel hub unit. A shaft or a bearing pin may be provided to rotatably mount the actuating lever of the first and second wheel drives.
[0036] A particularly ergonomic, joint-friendly, and efficient wheelchair drive is achieved when the operating levers of the first and second manual wheel drives are adjustable in length. The length of the operating lever can vary depending on its position. This length adjustment can be made possible, for example, by having the operating levers of the first and second manual wheel drives have inner and outer sections that can be telescopically extended relative to each other.
[0037] It is particularly preferred if the actuating lever of the first and second manual wheel drives can each be guided along a closed, non-circular guide on a guide plate, such that the length of the actuating lever changes during rotation. The guide can be designed, for example, as a rail or cam guide. A guide element, such as a guide pin, arranged on each actuating lever can be connected to and guided by the rail or cam guide. The guide element and the rail or cam guide thus ensure a change in the length of each actuating lever during rotation. The axis of rotation of the actuating lever remains fixed to the guide plate.
[0038] It is advantageous if the curve is a preferably substantially teardrop-shaped closed curve with a wide and a narrow end curve section, wherein each end curve section has a vertex and the narrow end curve section of the closed curve points towards the backrest of the wheelchair. This curve shape represents the result of an optimization problem in which the power transmitted from the muscles to the wheelchair wheel was maximized while reducing joint deflection. The end curve sections can be approximated by circular arcs. According to the invention, the narrow end curve section of the curve has a smaller approximate curve radius than the wide end curve section.
[0039] A particularly efficient curve shape with regard to force transmission and joint protection is achieved when a longitudinal axis running between the apexes of the wide and narrow end curve sections is inclined at least 5°, preferably at least 10°, preferably substantially 15°, but not more than 30°, to the horizontal, especially with the wide end curve section pointing downwards. The wide end curve section is preferably inclined downwards towards the seat surface or towards a floor surface.
[0040] A particularly favorable implementation form results when the curve can be described essentially by the following mathematical equations: 1 sin(" (ii sin" Hl 2 * ff )
[0041]
[0042] , where 0 corresponds to an angle as the running coordinate, the coordinates X and Y describe the path of the guide in a Cartesian coordinate system, the parameter β is set between -20° and 30°, the parameters A and B between 0.01 m and 0.25 m, and the parameter n between 0.2 and 0.9. The running coordinate 0 preferably has values between 0 and 2*n or between 0° and 360°. The curve described by the given equations essentially corresponds to a particularly favorable path of the guide. Depending on the perspective, this can also be mirrored. However, the actual orientation of the guide described by the curve is such that the narrow end curve section points towards the backrest of the wheelchair, and the longitudinal axis is preferably inclined downwards with the wide end curve section, i.e., towards a floor surface or the seat surface.The shape of the guide may expediently deviate slightly from the curve described by the equations above, for example to smooth out discontinuities. Particularly in the narrow end-curve region, it is advantageous for the rotary movement of the actuating lever if the curve or the guide is flattened.
[0043] The invention is described in more detail below with reference to figures, to which it is not, however, limited. These show:
[0044] Fig. 1 shows a wheelchair according to the invention;
[0045] Fig. 2 the first wheel hub unit in a state installed in a first wheel; Fig. 3 the first wheel hub unit in a first position in a cross-section;
[0046] Fig. 4 shows the first wheel hub unit in a second position in a cross-section;
[0047] Fig. 5 shows the first wheel hub unit in a third position in a cross-section; and
[0048] Fig. 6 shows the first wheel hub unit in a fourth position in a cross-section.
[0049] Fig. 1 shows a wheelchair 1 with a seat 2, a backrest 3, a first wheel 4a, and a second wheel 4b. The wheels 4a and 4b can be rotated forward (V) and backward (R). Viewed from the front, the wheelchair 1 also has additional wheels 5, which have a smaller diameter than the wheels 4a and 4b. These additional wheels 5 are mounted on support bars 6, to which footrests 7 for supporting the feet of a wheelchair user (not shown) can also be attached. The support bars 6 can be attached to a base frame 8 of the wheelchair 1. Handles 9 for pushing the wheelchair 1 are arranged on the backrest 3.
[0050] To propel the wheelchair 1, a first manual wheel drive 10a and a second manual wheel drive 10b are provided on opposite sides of the wheelchair 1. The wheel drives 10a and 10b are purely manual drives that can be actuated by hand. Each wheel drive 10a and 10b has a rotatably mounted actuating lever 11, which is preferably length-adjustable. The length adjustment is made possible by telescopic actuating lever sections. The actuating levers 11 can have rotatably mounted handles 51 for gripping by a wheelchair user. Each of the two wheel drives 10a and 10b has a guide plate 12 with a non-circular guide 13. The guide 13 can, for example, be designed as a rail or cam guide. The guide 13 causes a change in length of the actuating lever 11 during its rotational movement.A guide element (not shown) arranged on the respective actuating lever 11, for example a guide pin, can be connected to and guided by the rail or cam guide. The guide element and the guide 13 thus ensure a change in length of the respective actuating lever 11 during the rotational movement. A particularly preferred embodiment of the guide 13 provides that the guide 13 corresponds to a preferably substantially teardrop-shaped closed curve 14 with a wide 15 and a narrow end curve section 16, wherein the end curve sections 15, 16 each have a vertex and the narrow end curve section 16 of the closed curve 14 points towards the backrest 3 of the wheelchair 1. A connecting line between the two vertices of the end curve sections 15, 16 is inclined downwards.
[0051] To transmit the rotary motion of the actuating levers 11 to a respective wheel hub unit 21a, 21b, a first power transmission unit 17a is assigned to the first wheel drive 10a and a second power transmission unit 17b to the second wheel drive 10b. The first 17a and the second power transmission unit 17b each preferably have a transmission belt 19, which can be guided closely to the wheelchair 1 by means of deflection pulleys (not visible), so that the transmission belt 19 is protected. The transmission belt 19 can also be guided behind covers. The transmission belt 19 can be a closed belt that is ribbed towards its center. To couple the transmission belts 19 of the power transmission units 17a, 17b with the actuating levers 11, the actuating levers 11 can be coupled with power transmission wheels, for example gears, around which the transmission belts 19 are guided.
[0052] According to the invention, a first wheel hub unit 21a is provided in or on a first wheel hub 20a of the first wheel 4a, and a second wheel hub unit 21b is provided in or on a second wheel hub 20b of the second wheel 4b. Particularly preferably, the first wheel hub 20a and the second wheel hub 20b each have a receiving space for the first 21a and second wheel hub unit 21b, respectively. The wheel hub units 21a and 21b are preferably identical but mirrored. According to the invention, the first wheel hub unit 21a is configured to
[0053] - in a first position a rotation of the first wheel 4a by the first manual wheel drive 10a in the forward direction V,
[0054] - in a second position a freewheel of the first wheel 4a,
[0055] - in a third position, braking of the first wheel 4a and
[0056] - in a fourth position, a rotation of the first wheel 4a by the first manual wheel drive 10a in the reverse direction R
[0057] to enable. Similarly, the second wheel hub unit 21b is designed to
[0058] - in a first position, a rotation of the second wheel 4b by the second manual wheel drive 10b in the forward direction V,
[0059] - in a second position a freewheel of the second wheel 4b,
[0060] - in a third position, braking of the second wheel 4b and
[0061] - in a fourth position, a rotation of the second wheel 4b by the second manual wheel drive 10b in the reverse direction R
[0062] To enable this. In one embodiment, the first 21a and the second wheel hub unit 21b can each have a coaster brake or be formed by one. This allows the first 21a and the second wheel hub unit 21b to be easily moved into the four positions.
[0063] The first wheel hub unit 21a and the second wheel hub unit 21b are identical in design, but preferably mirror images of each other. Elements and features of one side of the wheelchair 1, in particular the first wheel hub unit 21a, are designated with the letter 'a' as an index. Elements and features of the other side of the wheelchair 1, in particular the second wheel hub unit 21b, are designated with the letter 'b' as an index. The operation of the wheelchair 1 is primarily explained with reference to the first wheel hub unit 21a. However, the above and following explanations concerning the first wheel hub unit 21a apply analogously to the second wheel hub unit 21b, which is preferably mirror images of the first.
[0064] Fig. 2 shows a cross-sectional view of the first wheel hub unit 21a, revealing that a first gear 22a is coupled to the first wheel hub unit 21a. The first gear 22a serves to transmit power via the transmission belt 19 of the first power transmission unit 17a. The first wheel hub unit 21a has a first outer wheel hub housing 27a, which is rotationally fixed to the first wheel hub 20a of the first wheel 4a.
[0065] Figures 3 to 6 show the first wheel hub unit 21a in the four positions.
[0066] Fig. 3 shows the first wheel hub unit 21a in the first position. As can be seen in Fig. 3, the first wheel hub unit 21a has a first rotating part 23a which is coupled to the first power transmission unit 17a. For this purpose, the first rotating part 23a forms the first gear 22a or is non-rotatably connected to it. As can be seen in Fig. 3, the first rotating part 23a has a first thread 24a, in particular an external thread, which engages with a first mating thread 25a, in particular an internal thread, of a displaceable first coupling element 26a, wherein a rotation of the first rotating part 23a causes a displacement of the first coupling element 26a within the first wheel hub housing 27a along a first axis 28a of the wheel hub unit 21a. The first axis 28a coincides with or is arranged parallel to an axis of rotation of the first wheel 4a.The first coupling element 26a can be displaced by rotating the first rotating part 23a along the first axis 28a. The first coupling element 26a is preferably substantially sleeve-shaped and has the mating thread 25a on an inner surface. The first rotating part 23a can be supported by means of a first ball bearing 29a. In the embodiment shown, the first rotating part 23a has a conically tapered shaped section 30a and a central shaped section 50a attached thereto with the first thread 24a. In the first position, the first coupling element 26a is in an end position and is connected via a frictional connection 18 to an inner wall 31a of the first wheel hub housing 27a of the first wheel hub unit 21a or directly to an inner wall 32a of the first wheel hub 20a, so that a rotary movement of the first manual wheel drive 10a is transmitted to the first wheel 4a.In particular, a rotation of the actuating lever 11 in the forward direction V is transmitted in this way, resulting in a rotation of the first wheel 4a in the forward direction V. The frictional engagement 18 is preferably a frictional engagement 18 rotating around the first axis 28a. In the end position of the first position, the first coupling part 26a can only be moved in one direction 100 along the first axis 28a, but not in the other direction 200.
[0067] By holding the actuating lever 11 of the first wheel drive 10a while the first wheel 4a rotates, or by slightly rotating the actuating lever 11 in the reverse direction R, the first wheel hub unit 21a can be moved into the second position (see Fig. 4). Through the interaction of the first thread 24a and the first mating thread 25a, the first coupling element 26a is pushed into a central position in which there is no frictional or positive engagement between the coupling element 26a and the inner wall 31a of the first wheel hub housing 27a or the inner wall 32a of the first wheel hub 20a. The frictional engagement 18 of the first position is thus released or significantly reduced. The second position can also be described as the freewheel position, in which the first wheel 4a can rotate without this rotational movement being transmitted to the actuating lever. There is no or only very slight frictional engagement of the first coupling element 26a.If a frictional connection exists in this position, it is the weakest frictional connection of all positions. To facilitate reliable engagement of the first coupling element 26a, the first wheel hub unit 21a can have a first spring 33a that biases the first coupling element 26a towards the center position. In the center position, the first coupling element 26a can be moved in both directions 100, 200 along the first axis 28a, i.e., back to the left in the direction 200 (first position of the first wheel hub unit 21a) or to the right in the direction 100 (third or fourth position of the first wheel hub unit 21a).
[0068] By rotating the actuating lever 11 of the first wheel drive 10a in the reverse direction R and then holding it in place, the first wheel hub unit 21a can be moved from the second position to the third position (see Fig. 5) by pushing the first coupling element 26a further in the direction 100. In the third position, the first coupling element 26a can be in or almost in an end position, which, however, is opposite to the end position according to the first position. If the first coupling element 26a is in the end position in the third position, the first coupling part 26a can only be moved in the other direction 200 along the first axis 28a, but not in the one direction 100.It is evident that in the third position, at least one first friction element 34a, in particular a brake pad, of the first wheel hub unit 21a is in frictional contact with the first coupling element 26a and the inner wall 31a of the first wheel hub housing 27a or the inner wall 32a of the first wheel hub 20a. A frictional connection 18 thus exists between the first friction element 34a, the first coupling element 26a, and the inner wall 31a or inner wall 32a. This converts the kinetic energy of the first wheel 4a into heat energy, thereby braking the first wheel 4a. For this purpose, the actuating lever 11 of the first wheel drive 10a is preferably held firmly by the wheelchair user. The frictional connection 18 in the third position is located in a different position than the frictional connection 18 in the first position. The frictional connection 18 can be a frictional connection 18 rotating around the first axis 28a.The first friction element 34a is pushed outwards away from the first axle 28a by the first coupling element 26a. The first friction element 34a is articulated to a first bearing element 35a and is pivotable. To enable reliable braking, a torque support 36a is provided, which can be connected to a first frame part 37a of the wheelchair 1. The first frame part 37a can, in turn, be connected to the base frame 8 of the wheelchair 1. In the embodiment shown, the first frame part 37a is U-shaped and at least partially surrounds the first wheel 4a.
[0069] By further rotating the actuating lever 11 of the first wheel drive 10a in the reverse direction R, the first wheel hub unit 21a can be moved into the fourth position (Fig. 6), in which, by rotating the actuating lever 11 of the first wheel drive 10a in the reverse direction R, the first wheel 4a can also be rotated in the reverse direction R. The fourth position can essentially correspond to the third position with respect to the position of the first coupling element 26a. However, in one embodiment, the first coupling element 26a may only be pressed into its end position in the fourth position. In other words, the first coupling element 26a may be pushed somewhat further in the direction 100, i.e., towards the bearing element 35a, than is the case in the third position. In the fourth position, the first coupling element 26a can thus be in its end position furthest towards 100.In the fourth position, the frictional engagement 18 can generate a greater frictional effect than in the third position. The rotational movement of the first wheel drive 10a in the reverse direction R can be transmitted to the first wheel 4a due to the frictional contact of the at least one first friction element 34a. In this process, the first rotating part 23a, the first coupling element 26a, the at least one first friction element 34a, and the bearing element 35a are moved in the reverse direction R. In particular, a rotation of the actuating lever 11 in the reverse direction R is transmitted in this way, resulting in a rotation of the first wheel 4a in the reverse direction R. In one embodiment of the invention, the position of the first coupling element 26a in the fourth position can correspond to the position of the first coupling element 26a in the third position.The only difference between the two positions is that a rotary movement of the actuating lever 11 of the first wheel drive 10a is transmitted in the reverse direction to the first wheel 4a.
[0070] By rotating the actuating lever 11 of the first wheel drive 10a in the forward direction V, the first wheel hub unit 21a can be moved from the fourth to the third position, then to the second, and finally to the first position. To realign the actuating levers 11, particularly after braking and cornering, a first clutch 38a and a second clutch can be provided, which can be manually activated by a first actuating element 39a and a second actuating element. The clutches, which can form a freewheel mechanism, decouple the actuating lever 11 of the first wheel drive 10a from the first wheel 4a and the actuating lever 11 of the second wheel drive 10b from the second wheel 4b. The first actuating element 39a can be arranged on the actuating lever 11 of the first wheel drive 10a or on its handle 51.The second actuating element can be arranged on the actuating lever 11 of the second wheel drive 10b or on its handle 51. The first 38a and the second clutch are preferably independent of the first 21a and second wheel hub unit 21b, in particular their second position, which also causes the wheels 4a, 4b to freewheel.
Claims
23 Claims:
1. Wheelchair ( 1 ) , having: a seat (2 ) ; a first wheel (4a) and a second wheel (4b) , wherein the first (4a) and the second wheel (4b) are arranged on opposite sides of the seat surface (2 ); and a first manual wheel drive (10a) for driving the first wheel (4a) and a second manual wheel drive (10b) for driving the second wheel (4b), wherein the first (10a) and the second manual wheel drive (10b) each have an actuating lever (11) and the first manual wheel drive (10a) is coupled to the first wheel (4a) via a first power transmission unit (17a) and the second manual wheel drive (10b) is coupled to the second wheel (4b) via a second power transmission unit (17b), characterized in that a first wheel hub unit (21a) is provided in or on a first wheel hub (20a) of the first wheel (4a) and a second wheel hub unit (21b) is provided in or on a second wheel hub (20b) of the second wheel (4b), wherein the first (21a) and the second wheel hub unit (21b) are designed to - in a first position a rotation of the first (4a) / second wheel (4b) by the first (10a) / second manual wheel drive (10a) in a forward direction (V) , - in a second position a free run of the first (4a) / second wheel (4b) , - in a third position, braking of the first (4a) / second wheel (4b) and - in a fourth position, a rotation of the first (4a) / second wheel (4b) by the first (10a) / second manual wheel drive (10b) in a reverse direction (R) to enable.
2. Wheelchair (1) according to claim 1, characterized in that the first wheel hub unit (21a) has a first rotating part (23a) coupled to the first power transmission unit (17a), and the second wheel hub unit (21b) has a second rotating part coupled to the second power transmission unit (17b).
3. Wheelchair (1) according to claim 2, characterized in that the first rotating part (23a) has a first thread (24a), in particular an external thread, which engages with a first mating thread (25a), in particular an internal thread, of a displaceable first coupling element (26a), wherein a rotation of the first rotating part (23a) causes a displacement of the first coupling element (26a) within a first wheel hub housing (27a). - the second rotating part has a second thread, in particular an external thread, which engages with a second mating thread, in particular an internal thread, of a displaceable second coupling element, wherein a rotation of the second rotating part causes a displacement of the second coupling element within a second wheel hub housing, wherein by displacing the first (26a) and the second coupling element the first (21a) and second wheel hub unit (21b) can be moved between the first, second, third and fourth positions.
4. Wheelchair ( 1 ) according to claim 3, characterized in that the first (26a) and the second coupling element are each arranged in an end position when the first (21a) and the second wheel hub unit (21b) are in the first and fourth positions.
5. Wheelchair ( 1 ) according to claim 3 or 4, characterized in that the first (26a) and the second coupling element are each arranged in a central position when the first (21a) and the second wheel hub unit (21b) are in the second position .
6. Wheelchair (1) according to claim 5, characterized in that the first wheel hub unit (21a) has a first spring (33a) which biases the first coupling element (26a) towards the center position when the first wheel hub unit (21a) is in the first position, and the second wheel hub unit (21b) has a second spring which biases the second coupling element towards the center position when the second wheel hub unit (21b) is in the first position.
1. Wheelchair (1) according to any one of claims 3 to 6, characterized in that - in the first, third and fourth positions of the first wheel hub unit (21a) the first coupling element (26a) is frictionally and / or positively connected to an inner wall (31a) of the first wheel hub housing (27a) of the first wheel hub unit (21a) or to an inner wall (32a) of the first wheel hub (20a), so that a rotary movement of the first manual wheel drive (10a) is transmitted to the first wheel (4a); and In the first, third and fourth positions of the second wheel hub unit (21b), the second coupling element is frictionally and / or positively connected to an inner wall of the second wheel hub housing or to an inner wall of the second wheel hub, so that a rotary movement of the second manual wheel drive (10b) is transmitted to the second wheel (4b).
8. Wheelchair ( 1 ) according to claim 7, characterized in that the first wheel hub unit (21a) has at least one first friction element (34a) and the second wheel hub unit (21b) has at least one second friction element, wherein the first friction element (34a) is in frictional contact with the first coupling element (26a) and the inner wall (31a, 32a) in the third and fourth positions of the first wheel hub unit (21a) and wherein the second friction element is in frictional contact with the second coupling element and the inner wall in the third and fourth positions of the second wheel hub unit (21b).
9. Wheelchair ( 1 ) according to one of claims 1 to 8, characterized by a first clutch (38a) which can be activated by a first actuating element (39a) so that the actuating lever (11) of the first wheel drive (10a) is decoupled from the first wheel (4a), and / or a second clutch which can be activated with a second actuating element, so that the actuating lever ( 11 ) of the second wheel drive ( 10b ) is decoupled from the second wheel (4b ).
10. Wheelchair ( 1 ) according to claim 9, characterized in that 26 the first actuating element ( 39a ) is arranged on the actuating lever ( 11 ) of the first wheel drive ( 10a ) and the second actuating element is arranged on the actuating lever ( 11 ) of the second wheel drive ( 10b ).
11. Wheelchair ( 1 ) according to one of claims 1 to 10 , characterized in that the first ( 17a ) and the second power transmission unit ( 17b ) each have a transmission belt ( 19 ) , a transmission chain and / or a transmission gearbox .
12. Wheelchair ( 1 ) according to one of claims 1 to 11 , characterized in that the actuating lever ( 11 ) of the first ( 10a ) and second wheel drive ( 10b ) is rotatably mounted, preferably rotatably by 360°, and the first power transmission unit ( 17a ) is designed to transmit a rotary movement of the actuating lever ( 11 ) of the first wheel drive ( 10a ) to the first wheel hub unit ( 21a ) and the second power transmission unit ( 17b ) is designed to transmit a rotary movement of the actuating lever ( 11 ) of the second wheel drive ( 10b ) to the second wheel hub unit ( 21b ).
13. Wheelchair ( 1 ) according to one of claims 11 or 12 , characterized in that the actuating lever ( 11 ) of the first ( 10a ) and the second manual wheel drive ( 10b ) is length-variable .
14. Wheelchair ( 1 ) according to claim 13 , characterized in that the actuating lever ( 11 ) of the first ( 10a ) and the second manual wheel drive ( 10b ) can each be guided along a closed guide ( 13 ) of a guide plate ( 12 ) which deviates from the circular shape, so that a change in length of the actuating lever ( 11 ) takes place during the rotational movement .