Motor vehicles – Motor-carrying attachments – Driven steering wheel type
Reexamination Certificate
2002-06-27
2004-07-27
Hurley, Kevin (Department: 3611)
Motor vehicles
Motor-carrying attachments
Driven steering wheel type
C180S211000
Reexamination Certificate
active
06766871
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of Use
The present invention relates to power units used to drive manually operated conventional wheelchairs, and more particularly, to novel power units that are automatically operated from a control switch to be attachable to and detachable from conventional wheelchairs for producing power driven wheelchairs.
Attachable power systems for manually operated wheelchairs are well known in the art. Various configurations have been designed with a variety of attachment methods, control methods, and detachment methods that allow the wheelchair to be converted back to a conventional manually operated wheelchair.
In all instances of prior art design known to the inventor the conventional wheelchair must be fitted with brackets, clamps, bars or sockets, or the apparatus must be pre-sized and manually configured to be custom fitted to a particular variant of a conventional manually operated wheelchair. In particular instances, the rear wheels must be removed to add specialized hubs, or powered hubs are added with the rear wheels still attached. In many instances of the prior art, both wheelchair modifications and pre-sizing of the power apparatus are required to adapt the power apparatus to the wheelchair. Adding attachment accessories to the wheelchair or having to pre-size the assembly requires tools, time and intervention on the part of the user or others that severely limits the convenience of use of the apparatus.
In the instances of a powered apparatus mounted under the wheelchair, the frame of the wheelchair has been the preferred location of attachment. Using the frame for attachment can place lateral or torsional stress on the frame of the wheelchair limiting the service life of the wheelchair. In many cases, holes must be drilled into the frame of the wheelchair to accommodate the attachment means, further limiting the service life of the wheelchair. Wheelchair users are very protective of their wheelchairs and are reluctant to make alterations or add attachments that may damage or reduce the service life of their wheelchair.
Although often referred to as “standard”, conventional wheelchairs of the manually operated type are manufactured by more than 60 different companies worldwide and embody significant variations in height, width, and frame layout. These variations have heretofore represented a difficult challenge to the manufacture of a universal or near-universal power apparatus that can be quickly and securely attached and detached from a wide variety of conventional manually operated wheelchairs.
If a wheelchair power apparatus is only going to be used by an individual user on a single specific wheelchair then the inconvenience represented by prior art designs is limited in frequency. However if the power apparatus is to be used by different wheelchair users with different wheelchairs on a regular basis, such as in a retail sales environment, then the inconvenience imposed by prior art designs becomes intolerable. Retrofitting of the wheelchair or pre-sizing of the device places a difficult burden on the user.
2. Background Setting of the Prior Art
Various types of electrical motor or engine powered drive units for wheelchairs are known or proposed in the prior art. U.S. Pat. No. 3,921,032 describes a front mounted drive apparatus that attaches to tubes that have been added to a conventional wheelchair in proximity to the armrests of the wheelchair. A ramp is used to raise the front wheels of the wheelchair, thus raising the receiving tubes to match the attachment bars of the apparatus. The apparatus is manually aligned by the user or attendant to receive the attachment bars.
U.S. Pat. No. 3,921,744 proposes a device that uses added receiving sockets mounted on the outer front frame of the wheelchair.
U.S. Pat. No. 4,386,672 proposes an apparatus that mounts to the under frame and crossbars of a foldable wheelchair. The apparatus width is preset. The user or attendant manually aligns and attaches a connector beneath the seat of the wheelchair. Throughout the prior art, one sees devices that require excessive intervention either by the user or a second party to prepare the propulsion device or the wheelchair for addition of a drive mechanism.
In a video by Stand Aid of Iowa Inc. describing a device called “Roll-Aid”, special brackets and lift bar are used to retrofit the wheelchair. Once retrofitted, the wheelchair is ready to accept the attachment of the Roll-Aid powering device. The wheelchair is rolled forward over the Roll-Aid and the brakes of the wheelchair are locked. The Roll-Aid is then put into reverse and attaches to the lift bar that was retrofitted to the wheelchair. A release cord is picked up off the ground and tied to the backrest or arm of the wheelchair.
Once the apparatus is attached, the brakes are released from the wheelchair and the Roll-Aid is ready to be put to use. When detachment is desired, the user locks the brakes on the wheelchair, reaches around the back or side of the wheel chair and manually manipulates the release cord. The video illustrates that the release cord is tied to the arm of the wheelchair as an attachment.
The lift bar required in the Roll-Aid retrofitting may prevent a foldable wheelchair from being folded until the bar is removed.
In the paper entitled “Manual Wheelchair Propulsion” obtained from the web site cosmos.buffalo.edu/t2rerc, the author points out “Experts and industry contacts mentioned power assisted add on units for manual wheelchairs as an area for further technology development and improvement.” A selection of specifically noted problems with current art include:
Adding a power assist unit to a manual wheelchair will increase the weight of the wheelchair and may offset the distribution of mass or balance and center of gravity, possibly making it more difficult for the user to propel when the power assist is disengaged.
Heavy power assist units can stress the wheelchair frame if the wheelchair is not specifically designed to accommodate the unit.
Some of the units are cumbersome to attach and detach, requiring the assistance of a second person.
A selection of specific issues to consider in the area of improved power assisted propulsion technology noted in the report include:
Can the products work across a wide range of wheelchairs?
Can the unit be easily engaged and disengaged as a function of power demand?
Can the products be less cumbersome to attach and detach?
As will be seen in the sections that follow, the apparatus of the present invention addresses these areas of needed technological improvement noted by the University at Buffalo and addresses additional deficiencies noted in the prior art.
SUMMARY OF THE INVENTION
The primary object of the present invention is to provide a power apparatus for a conventional manually operated wheelchair that is easily attached to the wheelchair by the unassisted user without the use of tools and that is readily adaptable across the broad range of wheelchair widths, heights, and frame layouts currently on the market.
It is a further object of the present invention to provide an attachable power apparatus for a conventional manually operated wheelchair wherein the power apparatus self adjusts to attach to the front wheels of wheelchairs having various front wheel spacings, front wheel thicknesses, and front wheel diameters.
It is a further object of the present invention to provide an attachable power apparatus for a conventional manually operated wheelchair wherein the power apparatus has a very low center of gravity to provide for greater stability and safety. The apparatus of the present invention is attached to the wheelchair at the lowest possible point to improve the stability of a standard manually operated wheelchair when in use.
It is a further object of the present invention to provide an attachable power apparatus for a conventional manually operated wheelchair that allows the wheelchair to be turned in a radius defined by the length of the overall assembly of the wheelchair and the power apparatus when t
Browning Bushman PC
Hurley Kevin
Torres Carlos A.
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