Brakes – Vehicle – Ground-engaging
Reexamination Certificate
2001-05-18
2002-02-19
Schwartz, Christopher P. (Department: 3613)
Brakes
Vehicle
Ground-engaging
C188S00200R, C280S304100
Reexamination Certificate
active
06347688
ABSTRACT:
BACKGROUND
The field of our invention is mechanisms for stabilizing wheelchairs, in particular mechanisms that prevent a wheelchair from moving in a backward direction when the patient is either entering or exiting the wheelchair. More particularly our invention relates to manual wheelchairs and not motorized wheelchairs. In the past wheelchairs were traditionally equipped with manually operated brakes that prevented the wheels from moving. These manual brakes required that the patient or assistant remember to engage the brakes prior to the patient either entering, or exiting, the wheelchair. The lever that controls the manual brakes were within easy reach of the patient. However the patient, or the assistant, could easily forget to engage the brake with the wheelchair rolling out from under the patient if the patient tried to exit the chair alone. The resulting fall could be harmful or even fatal. The same result could occur if the brakes were not engaged prior to the patient trying to enter the wheelchair. With patients that have diminished capacity the possibility is always present that the patient could disengage the brake and forget. There have been several inventions that have attempted to overcome this problem using locks that are engaged on the wheels when the patients weight is partially removed from the seat area. The disadvantage with these inventions is that they require major modifications to existing wheelchairs and in many instances cannot be used to modify so called standard wheelchairs. These inventions are also flawed in that the wheelchair may easily flip over backward during the patients entry or exit as the patient places his/her weight on the back portion of the armrests.
The uncontrolled movement of the wheelchair in a backward direction when the patient is either entering or exiting the wheelchair is the greatest danger and the specific risk that the present invention attempts to overcome. Due to the restriction of backward movement that results when the patients weight is partially or fully removed from the seat area of a wheelchair a bypass mechanism is required in order that the wheelchair may be easily moved when empty.
The present invention provides an improved wheelchair stabilizer that prevents the wheelchair from moving in a backward direction when the patient is either entering or exiting the wheelchair.
An object of the invention is to provide a wheelchair stabilizer that may be easily and inexpensively adapted to existing wheelchairs.
A further object of the invention is to provide an improved wheelchair stabilizer that provides for a pressure activated bypass mechanism that permits easy movement of the wheelchair when empty and further that the bypass mechanism return to neutral when not pressurized.
SUMMARY OF THE INVENTION
The invention portrayed is an improved Wheelchair Rollback Stop for wheelchairs, of the type typically used on wheelchairs that are utilized by patients at nursing homes and hospitals.
The invention is a new and improved wheelchair stabilizer that prevents a wheelchair from moving in a backward direction when the patient is either entering or exiting the wheelchair.
The present invention is an improvement on current wheelchair safety devices. Our invention prevents a wheelchair from rolling backward as the occupant attempts to enter or exit the wheelchair. This device is necessary because many patients with cognitive loss and who suffer from stokes cannot be taught to lock their wheelchairs prior to entering or exiting the wheelchair. This leads to falls, many with injury to the patient. The improvements we made are as follows: 1. Prevents the wheelchair from rolling backwards when entering, as well as exiting, the wheelchair; 2. Stronger and more durable, because our device stops the wheelchair with the use of two levers, one on each axle, that apply pressure to the floor rather than the wheels. This design allows the device to be manufactured out of much thicker material than other similar devices; 3. Our device does not prevent the wheelchair from folding, for easy transport and storage. 4. Our device is safer because all components are under the wheelchair out of reach of the occupant and nearby patients.
The uncontrolled movement of the wheelchair in a backward direction when the patient is either entering or exiting the wheelchair is the greatest danger and the specific risk that the present invention attempts to overcome. Due to the restriction of backward movement that results when the patients weight is partially or fully removed from the seat area of a wheelchair a bypass mechanism is required in order that the wheelchair may be easily moved when empty. The bypass mechanism that is included in the invention is hand pressure activated that permits easy movement of the wheelchair when empty and further provides that the bypass mechanism return to neutral when not pressurized. Other bypass mechanisms could easily be used.
All component parts are out of reach of the patient thereby eliminating the possibility of the stabilizer being deactivated by the patient.
The invention incorporates a multi part lever mechanism that is activated when no patient is seated on the seat area of the wheelchair, when the patient is preparing (or being assisted) to sit on the seat area and the patients weight is not fully pressing on the seat area, or the patient is getting up (or being assisted) from the seat area of the wheelchair and the patients weight pushing on the seat area is being reduced. The lever mechanism is deactivated when the seat area of the wheelchair is depressed by the patients weight. When the lever mechanism is activated a plurality of posts with tips that include friction means are pressed against the ground preventing the wheelchair from freely rolling, in particular in a backward direction. The wheelchair will roll forward in a normal manner.
The invention may be easily added to modify existing wheelchairs. The axle bolts of the unmodified wheelchairs are removed and longer bolts are substituted. The longer bolts act as a fulcrum. Bearings that are sized and shaped to fit on the bolts are fixedly attached to the major members of the levers, the major members are tubular. Rod like members that are bent at an angle are sized and shaped to have a first end slideably fit within the first end of the tubular major members. Cane tip members with friction tips, on one end, are sized and shaped to have the non tip end slideably fit within the second end of the tubular major members. The usual configuration has a right side lever and a left side lever. The left rod like member and right rod like member are positioned in order that their second ends are positioned beneath the seat area of the wheelchair. A plurality of springs are positioned in order to force the left and right rod like members against the bottom of the seat area. A plurality of adjustable stops are attached to the right side and left side lever. Th e adjustable stops are positioned to come in contact with a frame member of the wheelchair frame in order that the upper movement of the left and right rod like member may be restricted. These two components result in the activation position of the lever being adjusted for the individual user of the wheelchair. The cane tip members make contact with the ground when the lever is in the activation position. The cane tip members are angled against the ground in order that resistance is increased when the wheelchair moves in a backward direction. A pressure activated bypass is provided that has a cable attached to the tubular major member of the lever. The cable is attached at a point between the cane tip member and the bearing and travels thru a bracket that is positioned on a frame member of the wheelchair that is above the tubular major member. As pressure is applied to a hand grip the cable is shortened resulting in the tubular major member being raised off the ground. When pressure is released from the hand grip the tubular major member is allowed to return to be in contact with the ground
While the inventi
Hall Janet C.
Hall Steven R.
Baird James F.
Schwartz Christopher P.
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