Patent Application
20240041674
This disclosure relates to a power add-on device for a manual wheelchair.
Many individuals with spinal cord injuries require the assistance of a wheelchair for mobility. Manually-operated wheelchairs can be physically taxing to operate for long periods of time, especially outdoors and in extreme elements. Electric wheelchairs alleviate some of the difficulties associated with manual wheelchairs but can be prohibitively expensive for many potential users.
Several patents disclose devices capable of electrically powering a manual wheelchair. For example, U.S. Pat. No. 8,684,113 to Laconis, entitled “Attachable, Powered Drive Apparatus for Wheelchairs,” discloses an assembly consisting of a single powered wheel and a steering column attached to the front of a manual wheelchair. Another patent, U.S. Pat. No. 9,144,525 to Richter, entitled “Motion Assistance System for Wheelchairs,” discloses a drive wheel attached to at least one point on the manual wheelchair. Yet another patent, KR101017146B1, discloses a pair of drive wheels attached to each rear wheel of the manual wheelchair.
Although such inventions can be useful and provide powered assistance, they fail to provide quick mobility, for long ranges, over a variety of terrains. Moreover, while these devices themselves typically do not contact the existing wheels of the manual wheelchair, even those devices which do contact the wheels lack the ability to quickly shift between manual and powered operation.
Embodiments described herein may include two elements that are attached to a manual wheelchair: a structural assembly that houses the power add-on device and a controller for operating the device. The structural assembly is attached such that a portion of the assembly, namely, the drive wheels, contacts the rear wheels of the manual wheelchair to provide powered assistance via frictional force. A controller is attached to the wheelchair such that a user sitting in the wheelchair can control the structural assembly. Of course, some embodiments could be “built-in” to a wheelchair such that nothing in this disclosure should be read to limit the application of the embodiments to an “add-on” or aftermarket device.
In one embodiment, the structural assembly is attached to the wheelchair in a fixed position behind the backrest of the wheelchair. The structural assembly is further positioned such that each of the drive wheels are in contact with one of the set of rear wheels of the wheelchair. The structural assembly includes a frame and a cover attached via a hinge such that the cover swings up to open and swings down to close. The frame houses several other elements of this embodiment, including at least one of each of the following: a power source, a piston assembly, a motor, a single-board computer, a temperature sensor, and a cooling fan. In one embodiment, the frame also contains two holes positioned on opposite sides of the frame facing the rear wheels of the wheelchair. In certain embodiments, the frame also contains two male latches positioned facing the rear wheels, and the cover contains at least one venting hole to regulate the temperature inside the structural assembly.
In one embodiment, the structural assembly is attached to the wheelchair via a top mount and bottom mount. The top mount comprises two strap assemblies each further comprising a strap mount, at least two pieces of webbed strap, and a side release buckle with a male and female portion. Each top mount is connected to a frame hole facing the rear wheels. The bottom mount comprises two rigid structures each further comprising a clamp and a female latch. The female latch attaches to the male latch on the frame.
In one embodiment, the controller is attached to the armrest of the wheelchair. The controller in this embodiment comprises a joystick, a “start” button, a “stop” button, and an “emergency stop” button.
In the above and other embodiments, the drive wheels act upon the rear wheels of the wheelchair in response to one or more electric motors. The motors turn the drive wheels using a gear assembly. The drive wheels, in contact with the rear wheels, generate a frictional force that turns the rear wheels without manual operation. The motors are in operational connection with a power source. In one embodiment, the power source is a battery.
Some embodiments also include two piston assemblies that can rapidly disengage the gear assembly to prevent the motor from acting upon the drive wheels, thereby quickly halting any powered assistance of the manual wheelchair. Each piston assembly is in contact with one motor and drive wheel through a gear assembly. Each piston assembly includes a linear actuator and a gear holder. The embodiments featuring a piston assembly could be “built in” to a motorized wheelchair rather than being part of an add-on or aftermarket device.
Many embodiments are operated by the user using the controller. The controller may utilize existing short-range wireless technology to communicate with the motorized components via a single-board computer. By way of example, in one embodiment, the controller contains a Bluetooth transceiver to interact with a Raspberry Pi computer attached to the frame. The controller includes a base to be attached to the wheelchair. The controller may be powered using AAA batteries and contains a battery indicator light.
With reference to
Handles 103 are attached on the left and right side of the frame. These handles allow for the powered device to be easily attached onto and removed from the wheelchair. The latching system 110 may include a top mount 111, attached to or near the handlebars of a wheelchair used to manually push a wheelchair user, and a bottom mount 116, attached to the vertical bars of the wheelchair on the left and right sides of the back seat of the wheelchair. Each top mount 111 may include two pieces of webbing, wherein one piece of webbing is attached on one end to a male strap clip 112 and on the other end to a female strap clip 113, such that the ends of the webbing may lock into a secure loop. The top mount 111 may further include the second piece of webbing with one end attached perpendicularly to the first piece of webbing and the other end attached to one of a set of strap mounts 114. The strap mounts may be affixed to the outer sides of the powered device 100, such that the top mount 111 securely attaches the powered device to the manual wheelchair. With reference to
The power add-on device includes a powered device 100 mounted onto the back of the wheelchair and controller 200 for controlling the device (for example, see
The drive wheels receive rotational force from the motor via the gearbox. The motor applies a rotational force that is transmitted through the bevel gear assembly to the piston assembly, and then transmitted from the piston assembly to the drive wheel assembly. The drive wheels then transmit their own rotational force to the wheels of the wheelchair.
In one embodiment, the motors 130 apply a force to the drive wheels 120 via a set of disassociated shafts. Each of the motors 130 are connected to a shaft internal to the structural assembly 100. Meanwhile, each of the drive wheels 120 are connected a separate shaft which protrudes out from the structural assembly 100 to allow the drive wheels to contact the rear wheels of the wheelchair. Each shaft is connected to a bevel gear. There is a small gap between the bevel gears. In this embodiment, the piston assembly contains a bevel gear such that, when the piston assembly is engaged (
With reference to
With reference to
The present embodiments improve upon the related art by allowing the user to manually operate the wheelchair without removing the powered device 100. When the piston assembly is disengaged, the spaced bevel gears prevent any rotational force from being transmitted from the motors 130 to the drive wheels 120. Furthermore, the disassociated shafts enable the drive wheels to move freely when the piston assembly is disengaged. Thus, when the device is shifted to “stop” or “emergency stop” mode, the drive wheels will freely move in response to a user's manual operation of the wheelchair. In other words, the user need not adjust or remove the powered device 100 to operate the wheelchair manually.
These advancements over the related art increase the safety of the user and the efficiency of the device. In prior systems that apply drive wheels to the rear wheel of the manual wheelchair, the drive wheels must be physically removed from the rear wheel to switch to manual assistance. This is because, unlike the embodiments herein, the related art does not utilize drive wheels that can freely rotate on the rear wheel when the device is powered off. Thus, if a related art device were suddenly switched off, the user would experience a sudden lurch caused by the rigid deactivated drive wheels in contact with the rear wheels. With the present disclosure, however, the freely rotating drive wheels allow a user to slowly decelerate in the wheelchair using their combined body weight with the weight of the wheelchair.
Furthermore, where the related art requires the user to manually adjust the device to switch between powered assistance and manual operation of the wheelchair-a process that can require several seconds or minutes, or require the assistance of another person, for each adjustment—the present disclosure allows the user to quickly toggle between powered and manual assistance using the controller 200 without adjusting the device itself and takes a fraction of the time to complete, versus the related art.
