Brakes – Vehicle
Reexamination Certificate
2000-08-09
2001-11-13
Oberleitner, Robert J. (Department: 3613)
Brakes
Vehicle
C188S031000, C188S069000, C280S304100
Reexamination Certificate
active
06315085
ABSTRACT:
BACKGROUND OF THE INVENTION
It has long been recognized that an occupant of a wheel chair can be injured, potentially severely, if the chair is not braked against unwanted motion prior to the applicant attempting to rise out of the chair. This danger occurs because many wheel chair users lack the strength or agility to move from a sitting to a standing position or from a standing position to a sitting position without applying downward pressure on the arms of the wheel chair to assist themselves. Although wheel chairs are equipped with braking mechanisms, these mechanisms are purely manual in operation. That is, the brake must be set by an affirmative motion of either the wheel chair user or the user's helper.
If the brake is not set, at a certain point in the movement from a sitting to a standing position, or from a standing to a sitting position, accompanied by downward force on the arms of the wheel chair, the force applied to the arms of the chair by the user is actually angled toward the back of the wheel chair instead of down towards the surface on which the wheel chair rests. This backward force causes the wheel chair to roll back away from the user, often before the user has gained his balance, causing the user to fall to the ground, frequently injuring the hips, coccyx, or the like.
The purpose of this invention is to provide a means to apply the brake in a semi automatic fashion as soon as the occupant attempts to rise from the chair to prevent such catastrophes as described above.
SUMMARY OF THE INVENTION
There have been many attempts to provide automatic or semi-automatic brake applicators for wheel chairs for many of the reasons set forth herein. Most of the prior art devices involve the use of springs which must be matched to the size and weight of the user to function properly or levers which not only must be tuned to the size and weight of the user, but also expose the user and the user's helper to numerous pinch points which can trap hands and fingers causing serious injury or clothing or blankets thus inhibiting the intended mode of operation of such devices.
For example, in U.S. Pat. No. 5,203,433 to Dugas, the wheel chair brake is actuated when the user rises from the seat. The seat is equipped with a spring to bias it in an upper position in which the brake is applied. The force of the spring is overcome by the weight of the user sitting in the chair thereby causing the brake to be released. Use of this device requires that the springs in the seat not be so powerful that a person who is light in weight cannot overcome its force, yet, at the same time be powerful enough to engage the brake when actuated.
U.S. Pat. No. 5,894,912 to Dobben also provides an automatic means to engage a braking device when the wheelchair is unoccupied. In the Dobben device, the brake is released when weight is placed upon sensing levers which run under the legs of the user, or alternatively, when brake actuation handles which are attached to the push handles of the wheel chair are squeezed. Again, in order for the device to function based upon the user's rising from the chair, the device must be tuned to the weight of the user. If clothing such is a blanket or quilt is trapped in the device, it may not release the brake upon occupancy of the chair by the user, or, alternatively, fail to set the brake as the user attempts to rise from the chair.
U.S. Pat. No. 4,350,227 to Knoche provides a spring loaded arm rest biased in a upper position connected to a rod which is in turn connected to a brake actuation lever. The upward biased arm rest is held in a lower position by the weight of the arm of the user. When the user's arm is lifted from the armrest, the spring loading moves the armrest to the upper position causing the rod to also move upward which in turn causes the brake to be engaged. Obviously, as will be seen, this design offers many drawbacks when compared to the present invention. The Knoche device, first of all, requires that springs of sufficient tension be selected to allow the weight of the arm of the user to depress the arm rest into the lower position while, at the same time, when the arm rest is unloaded, the spring must be strong enough to cause the brake to engage. Additionally, the arms of the user must remain on the armrest at all times, otherwise the brakes will be engaged by the upward motion of the rod in response to the armrest being raised to the upper position as a result of the lack of a depressing weight on the arm rest.
REFERENCES:
patent: D. 412869 (1999-08-01), Bissell
patent: 3302757 (1967-02-01), Eagleson, Jr. et al.
patent: 4320818 (1982-03-01), Knoche
patent: 4350227 (1982-09-01), Knoche
patent: 4623043 (1986-11-01), Babilas
patent: 4852697 (1989-08-01), Kulik
patent: 5203433 (1993-04-01), Dugas
patent: 5358266 (1994-10-01), Roth et al.
patent: 5492355 (1996-02-01), Berry
patent: 5799756 (1998-09-01), Roberts et al.
patent: 5894912 (1999-04-01), Dobben
Oberleitner Robert J.
Torres Melanie
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