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US4987978A Expired / Lapsed US ⏱️ 0.0 years remaining

Wheelchair safety brakes

Assignee: Individual
•
Filing: 1989-10-10
•
Granted: 1991-01-29
•
Expires: 2009-10-10
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Abstract

Abstract A safety brake for use on an invalid wheelchair, specifically for the purpose of making travel up an incline, such as a ramp, easier and safer. When ascending an incline, the user often has difficulty getting a new grip quickly enough to avoid rolling back downhill. The present invention can, at the user's option, be set to permit travel forward only, or backward only. Thus, it permits the user to safely move up an incline either forward or backward without risk of rolling down when changing the grip of the hands. It consists of a somewhat egg shaped (when viewed from the end) cam on a housing, which has longitudinal serrations on both sides to grip the tire, and which housing is rotatably mounted on a core. The core having two cam segments engageable by a spring loaded cam follower which serves to urge the serrations of the housing against the tire of the wheelchair to permit travel in only one direction, depending upon which of the two cam segments the follower is set to engage, at the user's option. The serrations on the housing cam's one side will slide over the tire in one direction while gripping it if it tries to turn in the other direction. This invention will be activated when the brake lever is set in locked position. When the brake lever is released the wheels can rotate in either direction in the normal way.

Inventors

  • 👤 Thoger G. Jungersen

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-26 11:23
CPC Classifications
A; A61; A61G; A61G5/00; A61G5/10; A61G5/1005; A61G5/1035; A61G5/1013; A61G5/1018; A61G5/101; B; B62; B62B; B62B5/00; B62B5/04; B62B5/0485

Claims Analysis

Total Claims: 4
Claim 1
Independent Claim 183 words
A safety brake mechanism for a wheelchair to prevent rollback when the user changes position of the hands while ascending an incline, such as a ramp, permitting the user to selectively travel forward only or backward only, comprising a frame attached to the wheelchair, a brake handle pivoted to the frame, a core member attached to the lever adjacent the tire of the wheelchair, an oval shaped housing having a serrated cam surface on opposite sides thereof, the housing being rotatably mounted on the core member, the core member having two activating cam segments, one for forward movement only, one for backward movement only, for cooperating with the housing for positioning thereof, a spring activated mechanism engaging either cam segment for locating the housing as described by the wheelchair user, actuation of the housing by the user causing one or the other of the serrated cam surfaces to contact the tire of the wheelchair in a manner permitting the serrated cam to slide over the surface of the tire in one direcion while engaging the tire to stop movement in the other direction.
Claim 2
Dependent Claim 183 words
A safety brake mechanism for a wheelchair to prevent rollback when the user changes position of the hands while ascending an incline, such as a ramp, permitting the user to selectively travel forward only or backward only, comprising a frame attached to the wheelchair, a brake handle pivoted to the frame, a core member attached to the lever adjacent the tire of the wheelchair, an oval shaped housing having a serrated cam surface on opposite sides thereof, the housing being rotatably mounted on the core member, the core member having two activating cam segments, one for forward movement only, one for backward movement only, for cooperating with the housing for positioning thereof, a spring activated mechanism engaging either cam segment for locating the housing as described by the wheelchair user, actuation of the housing by the user causing one or the other of the serrated cam surfaces to contact the tire of the wheelchair in a manner permitting the serrated cam to slide over the surface of the tire in one direcion while engaging the tire to stop movement in the other direction.
Claim 3
Dependent Claim 20 words
A brake as in claim 1 in which the activating cam segments are located in the end of the core.
Claim 4
Dependent Claim 22 words
A brake as in claim 1 is which a control lever actuated by the user in an integral part of the housing.

References Cited (Backward Citations)

GB1243032A Cited
GB2110780A Cited
US4589525A Cited
US4887830A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1994-01-28 1994-07-30 1995-01-29 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1998-01-28 1998-07-30 1999-01-29 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 2002-01-28 2002-07-30 2003-01-29 $7700.00 Window Closed / Lapsed

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