Land vehicles – Wheeled – Occupant propelled type
Reexamination Certificate
2002-05-23
2003-10-21
Lerner, Avraham (Department: 3618)
Land vehicles
Wheeled
Occupant propelled type
C188S00200R, C301S006800
Reexamination Certificate
active
06634665
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to the field of wheelchairs and, more specifically, to an electrical braking system and quick release, detachable wheels for manual wheelchairs.
2. Description of the Related Prior Arts
Numerous types of braking mechanisms for manual wheelchairs are known in the art. The most typical manual wheelchair brake is a manual “over center” locking device which is activated by a lever arm and, when forced into its locking position, presses a braking member against the surface of the wheelchair tire creating a frictional braking action. Several factors mitigate against the usefulness and reliability of these types of brakes. Loss of tire pressure reduces the frictional force exerted by the crossbar on the tire and hence reduces the braking effect. A significant air pressure loss leaves these brakes useless. During transfer in and out of the chair, this type of brake allows the tire to slide underneath the crossbar and the wheelchair to move. Similarly, the brakes are ineffective and will not adequately hold the wheelchair on an incline. Other types of manual brakes include caliper type brakes manually activated with a lever arm mounted to a cable and brake assembly causing brake pads to press against the rim of the wheelchair wheel.
In these types of brakes, the frictional braking force exerted is directly related to the manual force which must be exerted on the lever arm by the brake operator to activate the brake. Wheelchair users who have arm or hand limitations may not be physically able to operate these brakes. These braking mechanisms only apply a braking force to one wheel. If an equal braking force is desired on both wheels, the user is required to use both arms and attempt to apply an equal force to both lever arms at the same time. This is difficult, if not impossible. Wheelchair frame and wheel design most often require the placement of the lever arms on the frame of the wheelchair near the user's knees. The placement of these lever arms interferes with the user's transfer in and out of the wheelchair. These lever arms require lifting the user's body in order to clear the lever during transfer.
A patent to Ross and Gunther, U.S. Pat. No. 5,358,266 describes a plate attached to a braking member, which applies a braking frictional force to the wheelchair tire when electronically activated by a solenoid rod. The solenoid rod is activated by means of a switch attached to the seat of the wheelchair. When the wheelchair user is raised out of the seat, the switch is activated and operates the braking mechanism. Also disclosed in this patent is a manually activated lever arm to operate the same braking member when the wheelchair user is seated. The same deficiencies discussed above apply to this wheelchair while the wheelchair user is seated. A wheelchair user with arm or hand limitations may not be able to operate the hand lever and the lever arm braking mechanism to apply a braking force to one wheel. In addition, the position of the lever arm may interfere with transfer in and out of the wheelchair.
Electric wheelchairs with various forms of braking means are common in the prior art. These braking means include gear reduction mechanisms, electromagnetic braking by means of a resistance applied to the electric motors, electronically activated frictional braking mechanisms where a solenoid is electrically energized to move brake shoes into frictional contact with a brake drum, and conventional manual brakes operated by a lever mechanism. These electric wheelchairs are heavy, cumbersome, difficult to transport, and do not promote physical activity by the user.
Wheelchair users have reason to frequently remove the wheels from their wheelchairs. It is often done for storage purposes, for brake adjustment, for wheel repair, and for wheel exchange. For example, in order to store a wheelchair in a vehicle, it is often desirable to remove the wheels.
Heretofore, the wheels on manual wheelchairs and other types of wheelchairs have been attached to the wheelchair frame by some type of hub with the wheels secured to the hub with nuts and bolts. In order to remove the wheels from the wheelchair, it has been necessary to unscrew and remove each of the nuts and bolts securing the wheel to the hub. This is a time consuming and cumbersome process. Once again, wheelchair users who have arm or hand limitations may not be physically able to remove the nuts and bolts.
More recently, it has become common in the art to attach wheels to manual wheelchairs using quick release locking pins which hold the wheel to the axle. In this type of design, it is difficult to also have a braking means on the wheelchair wheel other than the manual “over center” locking device which presses a braking member against the surface of the tire as described herein. Heretofore, other brakes have been ineffective on wheelchairs with quick release locking pins because the braking means had to be released and moved or disassembled in order to remove the wheel and thereby defeating the purpose of the quick release locking pin.
It is desirable to have a lightweight, manual wheelchair with an effective easily operatable electronic braking mechanism and, at the same time, quick release detachable wheels.
SUMMARY OF THE INVENTION
It is an object of this invention to provide an electronically activated braking system for a lightweight, manual wheelchair, which allows the wheelchair to maintain its lightweight and maneuverability characteristics.
It is a further object of this invention to have an electronically activated braking system for manual wheelchairs which eliminates the need for users of the wheelchair to manually operate brakes by means of a lever mechanism.
It is a further object of this invention to provide a braking system for manual wheelchairs, which provides equal braking force to both wheels of a wheelchair simultaneously.
It is a further object of this invention to provide a braking means for a manual wheelchair, which can be activated without the use of a manually operated lever that interferes with transfer in and out of the wheelchair by the user.
It is a further object of this invention to provide a braking means for manual wheelchairs, which eliminates movement of the wheelchairs on inclines and during transfer in and out of the wheelchair by the user.
It is a further object of this invention to provide a braking means for manual wheelchairs, which allows for detaching the wheelchair wheels without disturbing the braking means.
It is a further object of this invention to provide for quick release, easily detachable wheels.
It is a further object of this invention to provide for detachable wheels, which eliminates the need for users of the wheelchair to unscrew numerous nut and bolt combinations in order to remove the wheel.
It is a further object of this invention to provide for quick release, easily detachable wheels which allow the wheels to be removed without removing the disk and brake assembly.
In order to achieve these objectives, this invention provides for an electronic braking system, which is comprised of a braking means, a cable pulley system for activating the braking means, a DC liner actuator with actuator rod connected to the cable pulley system, a motion limit switch, a rechargeable twelve-volt battery electronically connected to the DC actuator, and a double throw control switch electronically connected to the battery for activating the battery power.
It is anticipated that the preferred braking means is a caliper-type brake positioned to clamp onto a metal disk mounted axially to a hub which rotates on the axle of each wheelchair wheel. The hub on which the disk is mounted interlocks with the hub on which the wheelchair wheel is mounted. The interlocking hubs are locked together with a locking pin, which extends axially through the center of the mated hubs such that the hubs are locked and rotate together when the wheelchair wheel is turned.
The locking pin is equipped with retractable
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