Drive unit for a wheelchair

Abstract

A drive unit (10) for a wheelchair (1) comprises a drive wheel (11) driven by an electric motor (12) for propelling the wheelchair (1), an energy storage device (19) connected to the electric motor (12) for supplying energy to the electric motor (12), and a control unit for controlling the operation of the electric motor (12). The drive unit (10) further comprises an actuating device (14) for continuous, repeating actuation of a movement sequence by a person sitting in the wheelchair (1).The drive unit (10) also has a sensor device for detecting the actuation of the actuating device (14) by the person, wherein actuation of the actuating device (14) acts exclusively via the sensor device on the drive of the drive wheel (11) and a control device of the drive unit (10) is configured to control the electric motor (12) to drive the drive wheel (11) depending on the actuation of the actuating device (14) detected by the sensor device.

Description

[0001] The invention relates to a drive device for a wheelchair, wherein the drive device has a drive wheel drivable by an electric motor for driving the wheelchair, an energy storage device connected to the electric motor for supplying energy to the electric motor and a control device for controlling the operation of the electric motor.

[0002] A wheelchair is typically used to transport people with physical disabilities. The wheelchair usually has a chair-like seat with pivoting wheels so that the seat can be moved along a surface by the wheels rolling. Often two large wheels are mounted at the rear of the seat on rigidly aligned pivot axes, while at the front of the seat two wheels that are smaller than the large wheels are pivoted to facilitate a change of direction when the wheelchair is moved. A wheelchair can be manually propelled by a person sitting in it, usually by manually driving the large rear wheels. For this purpose, an outer concentric rim or an additional ring is often formed or attached to the large wheels.A wheelchair can also be moved by a second person who grasps the wheelchair using handles usually located behind the seat and pushes it in front of them.

[0003] Various drive devices are also known in practice with the help of which a wheelchair can be propelled and moved without the person sitting in the wheelchair having to grasp and turn the large wheels, and without an additional person being needed to push or pull the wheelchair. For example, with a drive device permanently connected to the wheelchair, an electric motor and a rechargeable energy storage device can be arranged under the seat and the two large wheels can be driven by the electric motor. The person sitting in the wheelchair only has to control the operation of the electric motor and thus the electric drive of the wheelchair using a suitable control device. A wheelchair equipped in this way has a high dead weight due to the additional drive device and cannot usually be folded or collapsed.

[0004] Drive devices are also known that can be detachably connected to the wheelchair and are only connected to the wheelchair for the duration of the drive device's use. Such drive devices have, for example, a hand crank that is connected to an additional drive wheel via a drive chain. Such a drive device can be connected and secured to the wheelchair with the aid of a suitable coupling device in such a way that the two front small wheels of the wheelchair are raised and only the drive wheel of the drive device and the two rear large wheels roll over the ground. By operating the hand crank, the person sitting in the wheelchair can drive the drive wheel of the drive device.Such a drive device can also have a gear with different transmission ratios or reductions, so that the power required to drive the wheelchair with the hand crank can be adapted to a desired travel path of the wheelchair or to personal needs or characteristics of the person sitting in the wheelchair.

[0005] Furthermore, drive devices for wheelchairs are known that can be connected to the wheelchair only when needed; these devices drive the drive wheel using an electric motor. The person sitting in the wheelchair then only needs to use a control device to control the desired operation of the electric motor and thus the movement of the wheelchair caused by the drive wheel, which can be achieved without any physical effort. Depending on the physical limitations of the person using the wheelchair, different control devices have been developed that can be operated in different ways, manually or using other body parts. Control devices are also known that can be operated and controlled without physical contact by the person, for example, through voice commands or gestures.

[0006] Drive systems with the components mentioned above are also known in practice. These, in addition to driving the drive wheel with an electric motor, also allow manual operation by the person sitting in the wheelchair. For this purpose, they also feature a hand crank connected to the drive wheel via a drive chain. The person sitting in the wheelchair can then either drive the wheelchair manually using the hand crank or, for example, have the drive wheel driven by the electric motor after gradually becoming tired.

[0007] It is considered an object of the present invention to design a drive device for a wheelchair in such a way that the drive device is designed to be as space-saving and low-maintenance as possible and enables high user acceptance.

[0008] This object is achieved according to the invention in that the drive device has an actuating device for a continuously repeating movement sequence by a person sitting in the wheelchair, in that the drive device has a sensor device for detecting the actuation of the actuating device by the person sitting in the wheelchair, in that an actuation of the actuating device acts on the drive of the drive wheel exclusively via the sensor device, and in that the control device is designed to control the electric motor for driving the drive wheel depending on the actuation of the actuating device detected by the sensor device.Unlike conventional drive systems, the control device is not operated via individual switches, a joystick, or a touchscreen, which can be used to convert individual movements of the person into control signals for activating the electric motor. Instead, a continuously repeated movement sequence is provided for continuous operation of the electric motor and the resulting drive of the drive wheel. With this sequence, the person sitting in the wheelchair actuates the actuating device, thereby causing the electric motor to drive the drive wheel and the wheelchair to move forward. The movement sequence specified by the actuating device can be adapted to the physical abilities of the person sitting in the wheelchair.Through the continuously repeated movement sequence required to move the wheelchair, the extremities used for the movement sequence or the body areas of the person involved in the movement sequence can be specifically trained and strengthened.

[0009] The continuously repeated sequence of movements can, for example, be carried out with one hand or with both hands of the person, with one foot or with both feet or legs of the person, or with the upper body or even with the shoulders or even with the head of the person. In many cases it is useful if the arms or legs of the person sitting in the wheelchair are trained and strengthened by operating the operating device. Since a wheelchair is often used by people with limited abilities or with paralysis of the lower body and in particular of the legs, the operating device is preferably designed so that the continuously repeated sequence of movements can be carried out with one hand or with both hands.

[0010] A suitable sensor device detects the continuously repeated movement sequence and uses it to control the electric motor driving the drive wheel. A mechanical operative connection between the actuating device and the drive wheel is neither required nor provided. The actuating device is connected via the sensor device solely for signal transmission to the electric motor and the drive wheel driven by it. The drive device therefore does not have a torque-transmitting drive train connecting the actuating device to the drive wheel. The drive device therefore requires only a few movably mounted components. In particular, no continuous drive train and, in particular, no drive chain or drive shaft are required to transmit mechanical actuation of the actuating device to the drive wheel.

[0011] The sensor device can be designed and configured such that only a time duration for a fully executed movement sequence or a number of fully executed movement sequences within a predetermined time interval is recorded. The sensor device can also be designed and configured such that the sensor device records a temporal progression of the individual movement sequences or a force or torque exerted by the person on the actuating device during the execution of a movement sequence. Depending on the characteristic variables to be recorded for the movement sequences, the sensor device can be based on a measuring principle adapted thereto and can comprise, for example, an optical sensor, a force sensor, or an electrical or magnetic sensor.

[0012] The sensor device can, for example, detect a rotary movement of the wheelchair's large wheels forced by the person sitting in the wheelchair and use this to control the electric motor that drives the drive wheel. The large wheels of the wheelchair then form the actuating device. The sensor signals are transmitted, expediently wirelessly, either to the control device or from the control device to the electric motor and the drive wheel driven by it. The electric motor and the drive wheel as well as the energy storage device are mounted on a drive device frame, which can be detachably connected to the wheelchair if necessary. In many cases, however, it is expedient for the drive device to have a separate actuating device that can be connected to the wheelchair together with the drive device frame or detached from it again.

[0013] The movement sequence specified by the actuating device can also be a substantially linear movement process, in which a linearly displaceable pressure plate or a gripping element is moved back and forth with a foot or hand. It is also conceivable for the legs and, in particular, the arms to perform a continuously repeated pivoting movement, such as a pumping movement with a pivoting arm, which is detected by the sensor device and used to control the electric motor.

[0014] According to an advantageous embodiment of the inventive concept, the actuating device has a crank mechanism with a crankshaft. The crank mechanism can be a pedal crank that can be operated with the person's feet or legs. It can also be a hand crank, whereby the crankshaft can be aligned vertically or, preferably, horizontally and set in rotation with the aid of suitably designed crank elements. A uniform rotary movement of the crank mechanism is perceived by many people as a pleasant and at the same time efficient movement sequence. Some conventional drive devices for a wheelchair already have hand cranks that can drive the drive wheel of the drive device via a mechanical connection usually designed as a bicycle chain.It has been shown that such an actuating device forms an actuating device which is easy and comfortable to operate for many people, so that a high level of user acceptance can also be expected for the drive device designed according to the invention.

[0015] In a particularly advantageous manner, it is optionally provided that the control device is configured such that, depending on a speed or effort with which the movement sequence is carried out during actuation of the actuating device, an adapted drive speed or drive power of the electric motor is specified. In many applications, it can expediently be provided that the faster the person performs the continuously repeated movement sequence specified by the actuating device, the faster the wheelchair is driven by the electric motor acting on the drive wheel. It can also be provided that the sensor device can be used to continuously detect a force or torque which is exerted by the person on the actuating device during execution of a movement sequence.Depending on the sensor values, the control device can then specify the drive power or a corresponding torque transmitted by the electric motor to the drive wheel. In many cases, it may be expedient for the drive power of the drive wheel to increase as the work exerted by the person during operation of the actuating device increases. The drive power transmitted by the electric motor to the drive wheel is then perceived as a manually applied drive power, which in conventional drive devices is generated by a drive train that mechanically transmits a force exerted by the person or a torque from the actuating device to the drive wheel and mechanically converts it into drive power.In this way, it is easier for one person to control the electrically driven drive wheel and intuitive use of the drive system is possible, which further improves user acceptance.

[0016] According to an advantageous embodiment of the inventive concept, the sensor device comprises a rotary encoder with which a rotational movement of the crankshaft of the crank device can be detected. The rotary encoder can, for example, be an incremental encoder that delivers a zero pulse and a number of step pulses for each complete revolution of the crankshaft. The rotary encoder can also be an absolute value encoder that outputs a unique sensor value for each angular position of the crankshaft. Regardless of the specific design of the rotary encoder, the rotary encoder can be used as a tachometer by, for example, recording and evaluating the time required for one complete revolution of the crankshaft or the time between two step pulses, or for a predetermined angular difference.Using a rotary encoder as a sensor device, the rotational movement of the crankshaft and thus a continuous actuation of the crank mechanism or the actuating device by the person sitting in the wheelchair can be detected and used to control the electric motor for driving the drive wheel.

[0017] It can also be provided that the electric motor also operates as a sensor, and a speed or current consumption during the movement of the electric motor, or a torque exerted by the electric motor, is recorded using suitable measuring devices and taken into account and used to control the electric motor. For example, it can be detected whether the drive system is moving the wheelchair over an uphill or downhill surface, or whether the drive wheel is spinning on a smooth surface.

[0018] It is optionally possible for the drive device to have a braking device with which the continuously repeated movement sequence during actuation of the actuating device, and in particular a rotational movement of the crankshaft of the crank device, can be counteracted. With a view to achieving the simplest possible design, the braking device can exert a fixed, predetermined braking effect on the actuating device or on the rotational movement of the crankshaft. It is also conceivable for the braking device to enable several different braking effects, which can be selectively selected and predetermined by the person for a braking effect exerted by the braking device on the actuating device or the crank device.It is also conceivable that a braking effect of the braking device can be changed as desired within a range specified by the braking device, so that the person can select any braking effect within the range specified by the braking device and have it exerted by the braking device on the actuating device.

[0019] By combining the actuating device with a braking device, the drive device can also be used as a training device by the person sitting in the wheelchair. It is also possible for only the braking effect of the braking device on the actuating device to be specified for a training session, and for the control device to not control the electric motor in a drive idle mode and therefore not drive the drive wheel. In this case, the drive device can be connected to the wheelchair without the drive wheel being driven and the wheelchair moving through continuous actuation of the actuating device in a training mode. In such a training mode, the person can sit in the wheelchair and actuate the actuating device of the drive device for training without the wheelchair being moved or displaced.It is also conceivable that the drive device does not need to be connected to the wheelchair for use as an exercise device, and that the person does not need to be sitting in the wheelchair to engage in physical exercise by continuously operating the drive device's actuation mechanism. This provides another possible use for the drive device, which can further increase user acceptance of the drive device.

[0020] According to a particularly advantageous embodiment of the inventive concept, the drive device comprises a generator device, with which the person sitting in the wheelchair can operate the generator to generate electrical energy. A generator shaft can, for example, be designed and used as the crankshaft of the crank device. It is also possible for the crankshaft of the crank device to be operatively connected to the generator device, and for the generator device to be operated by a rotational movement of the crankshaft of the crank device.In the event that the actuating device does not specify a circular movement sequence for actuating the actuating device, a generator operation of the generator device can still be enabled and carried out by means of a suitably designed operative connection in which a suitably designed gear unit connects the actuating device to the generator device.

[0021] The generator device can be permanently connected to the actuating device. In this case, the sensor device can be arranged on the generator device and detect the actuation of the actuating device by the person via the resulting generator operation.

[0022] Alternatively, it is also conceivable for the generator device to be optionally connected to the actuating device or decoupled from the actuating device. The generator device can also be designed so that the generator device can also be used as a braking device to counteract the actuation of the actuating device.

[0023] By operating the actuating device, the person sitting in the wheelchair can not only control the drive of the drive wheel, which is provided by the drive mechanism, and thus the movement and, in particular, the propulsion of the wheelchair, but can also simultaneously generate the electrical energy required to drive the drive wheel. In this way, the wheelchair can be driven and moved by the drive mechanism solely through the movement sequence continuously repeated by the person.

[0024] Optionally, the energy storage device may include a rechargeable accumulator, and the drive device may be configured such that the energy storage device can be charged by the generator device. Conveniently, the accumulator may also be connected to a power supply device, such as a standard household power grid, and charged via that power supply.

[0025] It is also possible for the person to operate the actuating device over a period of time in a training mode, thereby generating electrical energy via the generator device, which is stored in the energy storage device without driving the drive wheel or moving the wheelchair. For example, before a planned longer journey with the drive device, the energy storage device can be charged in advance in a training mode, and the electrical energy required for the planned longer journey can be generated by the person operating the actuating device. A separate connection of the energy storage device to a power supply network and separate charging of the energy storage device are then unnecessary.

[0026] According to an essential aspect of the inventive concept, it is provided that the actuating device or the generator device has no mechanical operative connection for transmitting drive power to other components of the drive device. Although the actuating device can, for example, be connected to a braking device or to a generator device in a force-transmitting or torque-transmitting manner, no drive power is transmitted to the drive wheel through such a mechanical operative connection. The operation of the electric motor and thus the drive of the drive wheel is controlled exclusively via sensor signals from the sensor device. The sensor signals from the sensor device can be transmitted either wired or wirelessly from the sensor device to the control device, where they can be suitably processed and converted into control signals for controlling the operation of the electric motor.The control signals can also be transmitted from the control unit to the electric motor either wired or wirelessly.

[0027] This allows the number of moving parts and components of the drive system to be reduced to a minimum. The drive system can therefore also be very lightweight and designed to be low-maintenance or largely maintenance-free. This makes it considerably easier for the person sitting in the wheelchair to use the drive system and to connect it to the wheelchair as needed, or to detach and remove it from the wheelchair.

[0028] To improve the drive and movement comfort of the drive system and the wheelchair powered by it, the drive wheel can optionally be pivoted about a pivot axis aligned transversely to the rotational axis of the drive wheel. By pivoting the drive wheel, a change in the direction of movement of the wheelchair can then be easily achieved.

[0029] The actuating device can be designed and arranged such that the person can simultaneously specify the orientation of the drive wheel during continuous actuation of the actuating device and can use the actuating device as a steering device for the drive wheel pivotably mounted about the pivot axis. It is also conceivable that, in addition to the actuating device, a separate steering device is provided, with which the orientation of the drive wheel can be specified.

[0030] The drive device expediently also has a coupling device for a detachable connection to a wheelchair. A wheelchair can then be easily retrofitted with the drive device and connected or detached as needed. The coupling device is advantageously designed so that the coupling device can be easily operated by the person sitting in the wheelchair, using as few and simple steps as possible, in order to connect the drive device to the wheelchair via the coupling device, or to detach it from the wheelchair again after the drive device has been used.

[0031] An exemplary embodiment of the invention is explained in more detail below, as shown in the drawings. It shows: Fig. 1 a perspective view of a wheelchair connected to a drive device via a coupling device, and Fig. 2 an enlarged detailed view of an area II of the Fig. 1 illustrated drive device with an actuating device for the drive device designed as a hand crank.

[0032] A wheelchair 1 depicted in the figures has a seat 2 for a person sitting in the wheelchair 1, whereby the person is not depicted in the figures. On a chair-like frame 3 of the wheelchair 1, a large wheel 5 is arranged on two frame rods 4 in a rear area of ​​the seat 2 on two opposite sides of the frame 3. The respective axes of rotation of the two large wheels 5 are rigidly aligned and the large wheels 5 are rotatably mounted on the frame 3 such that rotation of the large wheels moves the wheelchair in a forward direction. In a front area of ​​the seat 2, two small wheels 6 are pivotally mounted on the frame 3 of the wheelchair 1, also on opposite sides of the frame 3.Handles 8 are arranged on a backrest 7 of the seat 2 of the wheelchair 1, with the aid of which a person standing or walking behind the wheelchair 1 can push and move the wheelchair 1 with a person sitting in it.

[0033] The wheelchair 1 is detachably connected to a drive device 10 via a coupling device 9. The drive device 10 has a pivotably mounted drive wheel 11, which can be driven by an electric motor 12. In the exemplary embodiment shown, the electric motor 12 is designed as a hub motor and is arranged in the drive wheel 11 to save space. The drive wheel 11 is connected to an actuating device 14 via a tube 13. The actuating device 14 has a hand crank 15 with two crank handles 17 arranged on opposite sides of a crankshaft 16. Using the crank handles 17, a person sitting in the wheelchair 1 can set the crankshaft 16 of the actuating device 14, designed as a hand crank 15, in a rotational movement.

[0034] The actuating device 14 is connected to a generator device 18 such that the crankshaft 16 is operatively connected to the generator device 18 to transmit torque. A rotational movement of the crankshaft 16 caused by the person actuates the generator device 18 and generates electrical energy. The electrical energy generated by the generator device 18 can be fed directly to the electric motor 12 and used to operate the electric motor 12. It is also possible for the electrical energy to be fed to an energy storage device 19 with one or more accumulators housed in the tube 13. The energy storage device 19 can also be connected to a standard household power supply network via a charging cable.

[0035] The generator device 18 can also be used as a braking device for the actuating device 14. It is generally possible to provide a separate braking device in addition to the generator device 18, although this is not shown in the figures.

[0036] To drive the wheelchair 1 with the drive device 10, the drive device 10 must be connected to the wheelchair 1 via the coupling device 9. A person sitting in the wheelchair 1 must continuously repeat the movement sequence specified by the actuating device 14 or the hand crank 15. The movement of the hand crank 15 is detected by a sensor device (not shown separately) and transmitted to a control device (also not shown separately). Based on sensor measurements from the sensor device, the control device generates control signals and controls the operation of the electric motor 12, which drives the drive wheel 11 and moves the wheelchair 1 connected to the drive device 10.The drive wheel 11 is pivotally mounted on the tube 13 and can be pivoted and aligned accordingly by pivoting the actuating device 14 during operation so that the wheelchair 1 driven by the drive wheel 11 is moved in the desired direction.

[0037] The drive device 10 can also be used as a training device. For this purpose, the drive device 10 can be put into a training mode in which the drive wheel 10 is not driven despite continuous actuation of the actuating device 14 by a person. The actuating device 14 can be used by the person to continuously perform the movement sequence specified by the actuating device 14, i.e., to continuously rotate the hand crank 15. This movement sequence can not only be used for training and to strengthen the person, but can also be used to generate electrical energy and store it in the energy storage device 19 in order to use this energy to operate the electric motor 12 and thus drive the wheelchair 1 at a later time.

Claims

[1] Drive device (10) for a wheelchair (1), wherein the drive device (10) has a drive wheel (11) drivable by an electric motor (12) for driving the wheelchair (1), an energy storage device (19) connected to the electric motor (12) for supplying energy to the electric motor (12) and a control device for controlling the operation of the electric motor (12), characterized bythat the drive device (10) has an actuating device (14) for a continuously repeating movement sequence by a person sitting in the wheelchair (1), that the drive device (10) has a sensor device for detecting the actuation of the actuating device (14) by the person, that an actuation of the actuating device (14) acts on the drive of the drive wheel (11) exclusively via the sensor device, and that the control device is designed to control the electric motor (12) for driving the drive wheel (11) depending on the actuation of the actuating device (14) detected by the sensor device. [2] Drive device (10) according to claim 1, characterized bythat the control device is arranged in such a way that, depending on a speed or an effort of force with which the movement sequence is carried out during the actuation of the actuating device (14), a drive speed or a drive power of the electric motor (12) adapted thereto is predetermined. [3] Drive device (10) according to claim 1 or claim 2, characterized by that the actuating device (14) has a crank device with a crankshaft (16). [4] Drive device (10) according to claim 3, characterized by that the sensor device has a rotary encoder with which a rotational movement of the crankshaft (16) of the crank device can be detected. [5] Drive device (10) according to one of the preceding claims, characterized bythat the drive device (10) has a braking device with which the continuously repeated movement sequence during the actuation of the actuating device (14) can be counteracted. [6] Drive device (10) according to one of the preceding claims, characterized by that the drive device (10) has a generator device (18) with which a generator operation for generating electrical energy can be carried out by the person sitting in the wheelchair (1). [7] Drive device (10) according to claim 6, characterized by that the energy storage device (19) has a rechargeable accumulator and that the drive device (10) is designed such that the energy storage device (19) can be charged with the generator device (18). [8] Drive device (10) according to one of the preceding claims, characterized bythat the actuating device (14) or the generator device (18) has no mechanical operative connection for transmitting a drive power to other components (11, 12) of the drive device (10). [9] Drive device (10) according to one of the preceding claims, characterized by that the drive wheel (11) is pivotally mounted about a pivot axis aligned transversely to a rotation axis of the drive wheel (11). [10] Drive device (10) according to claim 9, characterized by that the drive device (10) has a steering device with which an orientation of the drive wheel (11) about the pivot axis can be predetermined. [11] Drive device (10) according to one of the preceding claims, characterized by that the drive device (10) has a coupling device (9) for a detachable connection to a wheelchair (1).

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