AUTOMATIC BRAKING DEVICE FOR HYDRAULIC PRESSURE CHAIR

• US 3,777,617 A
• Filed: 11/16/1971
• Issued: 12/11/1973
• Est. Priority Date: 12/14/1970
• Status: Expired due to Term

• Current Assignee: Masaharu Okiyama
• Original Assignee: Masaharu Okiyama
• Inventors: Okiyama, Masaharu
• Primary Examiner(s): Schwadron, Martin P.
• Assistant Examiner(s): Zupcic, A. M.
• Application Number:
  US05/199,276
• Time in Patent Office: 756 Days
• Field of Search: 91/41,44 92/24,25,27,28 60/52HD 188/67 248/410 297/347
• US Class Current: 91/44
• CPC Class Codes: A47C 3/30 with vertically-acting fluid cylinder
• CPC Class Codes: F15B 15/262 using friction, e.g. brake pads

Abstract

This invention provides an automatic braking device for vertically adjustable hydraulic chairs. The invention is incorporated within the hydraulics and instantly stops and locks the chair seat at any height, without the requirement of external locking means.

Claims

1. An automatic braking device for a hydraulic lift system comprising:

a. a plunger having a first axis along its length connected to a load and moveable under hydraulic pressure along said first axis;

b. a U-shaped brake bracelet having two legs disposed in a common plane which is perpendicular to said first axis and a gap between said legs, said legs and said gap encircling said plunger, said legs being operative to move in said plane to close and open said gap;

c. framework and pivot means for pivotally mounting said framework means about a second axis which is perpendicular to said first axis, said framework means being pivotally moveable;

d. a brake shoe disposed on said framework means which is operative to move said legs to close and open said gap in response to said pivoting movement of said framework means; and

e. means to pivotally move said framework about said second axis.

2. An automatic braking device as claimed in claim 1 wherein said means to pivotally move said framework means comprises a piston rod moveable in a direction parallel to said plunger and a coil spring operative to bias said piston rod in a first position.

3. An automatic braking device as claimed in claim 2 further comprising a first chamber for housing said plunger and a second chamber for housing said piston rod, said chambers being in communication with each other by means of at least one passageway.

4. An automatic braking device as claimed in claim 3 further comprising valve means for controlling hydraulic flow into said chambers, said valve means comprising a spring operative to react more quickly than said coil spring to permit hydraulic flow into said first chamber after movement of said piston rod is stopped.

5. An automatic braking device as claimed in claim 1 wherein said brake bracelet further comprises a face and wherein said brake shoe slants in relation to said face, said slanting of said brake shoe being operative to move said brake bracelet legs to close and open said gap upon pivoting of said brake bracelet.