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US3783976A Expired / Lapsed US ⏱️ 0.0 years remaining

Safety device for hydraulically operated lift

Assignee: Individual
•
Filing: 1972-07-26
•
Granted: 1974-01-08
•
Expires: 1992-07-26
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Abstract

Abstract The device is shown as associated in the usual subfloor pit with a conventional hydraulically powered lift mechanism to loss or substantial droppage of the hydraulic pressure correspondingly depressurizes the safety cylinder unit, enabling its built-in housing is mounted atop the lift''s power cylinder superstructure; and a pivotal, bifurcated arm or fork-shaped actuator head embraces the fixed housing, an operating extension tail of said head projecting from one side of the latter. The furcations of said pivoted head carry trunnion-like actuator pins, which extend through vertically elongated slots in opposite sides of the fixed housing; and the ends of said trunnions are received in outer side openings of each of a pair of identical collets. These are actuable in the fixed housing parallel to the axis of the lift''s hydraulic power rod or piston for releasable frictional radial engagement with said rod of arcuate inner collet areas, thus to safety-halt an undesired downward retrograde movement of the latter. To this end external tapered collet wedge surfaces engage correspondingly tapered internal wedge surfaces of the fixed housing. The same source of hydraulic power which operates the lift rod is at all times in communication with a spring return-type safety cylinder unit of the device; and the plunger of this unit is connected to the extension tail of the pivotal actuator head. This is in a manner such that normal hydraulic pressure urges the head in a direction to de-wedge the collets from clamping engagement with the lift power rod, through the agency of the head''s trunnions. A LOSS OR SUBSTANTIAL DROPPAGE OF THE HYDRAULIC PRESSURE CPRRES PMDOMG:U DE RESSIROZES THE SAFETY CYLINDER UNIT, ENABLING ITS BUILT-in return spring to operate the actuator head in the opposite direction and cause the collet members to grip the power rod against fall. Supplemental spring means normally assist in insuring separation of the collets from the rod when the device is not in operation.

Inventors

  • 👤 J Kerr

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-03 19:05
CPC Classifications
B; B66; B66F; B66F7/00; B66F7/28; B66F7/10; B66F7/16; B66F7/18

Claims Analysis

Total Claims: 14
Claim 1
Independent Claim 213 words
A safety device for a lift or like rod axially powered operationally under fluid pressure in one direction but normally subject to retrograde axial movement in the event of a predetermined droppage of its fluid pressure operating power, said device being actuable to check said retrograde movement and comprising collet-type means releasably engageable with said rod to so check the latter, and means operatively connected to said checking means, being responsibly powered by the source of fluid pressure operating power for said rod, to actuate said safety device in said event of operating power droppage, said collettype checking means comprising a collet unit including a pair of like collet members disposed radially outwardly of said fluid pressure-powered rod and movable radially inward to grip the latter, and a housing unit within which said collet members operate, said units having coacting axially tapered wedging surfaces operatively engageable with one another upon relative axial shift of said units to releasably radially engage said collet members with said rod, and a single actuator head operatively connecting one of said units to said responsively powered means to effect said relative axial shift of said units, anD an attendant radial shift of said collet members to grip said rod, in said event of fluid pressure operating power droppage.
Claim 2
Dependent Claim 213 words
A safety device for a lift or like rod axially powered operationally under fluid pressure in one direction but normally subject to retrograde axial movement in the event of a predetermined droppage of its fluid pressure operating power, said device being actuable to check said retrograde movement and comprising collet-type means releasably engageable with said rod to so check the latter, and means operatively connected to said checking means, being responsibly powered by the source of fluid pressure operating power for said rod, to actuate said safety device in said event of operating power droppage, said collettype checking means comprising a collet unit including a pair of like collet members disposed radially outwardly of said fluid pressure-powered rod and movable radially inward to grip the latter, and a housing unit within which said collet members operate, said units having coacting axially tapered wedging surfaces operatively engageable with one another upon relative axial shift of said units to releasably radially engage said collet members with said rod, and a single actuator head operatively connecting one of said units to said responsively powered means to effect said relative axial shift of said units, anD an attendant radial shift of said collet members to grip said rod, in said event of fluid pressure operating power droppage.
Claim 3
Dependent Claim 56 words
The safety device of claim 1, in which said housing unit is a fixed one within which said collet members operate parallel to the operating axis of said rod, said actuator head operatively connecting both of said collet members to said responsively powered means to effect axial shift of said collet members in the housing unit.
Claim 4
Dependent Claim 54 words
The safety device of claim 2, in which said responsively powered means comprises a fluid pressure cylinder unit having an element operated in one direction only under fluid pressure from said source, said element being operatively connected to said actuator head to effect said releasable checking engagement of said collet members with said rod.
Claim 5
Dependent Claim 27 words
The safety device of claim 3, in which said operated element of said cylinder unit is spring-returned in a direction opposite its direction of fluid pressure operation.
Claim 6
Dependent Claim 42 words
The safety device of claim 4, in which said operated element of said cylinder unit has pivoted arm means operatively connecting the same with said actuator head and through said head with said collet members for said axial shift of the latter.
Claim 7
Dependent Claim 32 words
The safety device of claim 4, in which said arm means has trunnion elements extending through said fixed housing unit for operating engagement with the respective collet members for said axial shift.
Claim 8
Dependent Claim 32 words
The safety device of claim 6, and further comprising means acting automatically on said collet members to release them from checking engagement with said rod upon restoration of fluid pressure operating power.
Claim 9
Dependent Claim 42 words
The safety device of claim 3, in which said operated element of said cylinder unit has pivoted arm means operatively connecting the same with said actuator head and through said head with said collet members for said axial shift of the latter.
Claim 10
Dependent Claim 32 words
The safety device of claim 8, in which said arm means has trunnion elements extending through said fixed housing unit for operating engagement with the respective collet members for said axial shift.
Claim 11
Dependent Claim 32 words
The safety device of claim 2, and further comprising means acting automatically on said collet members to release them from checking engagement with said rod upon restoration of fluid pressure operating power.
Claim 12
Dependent Claim 54 words
The safety device of claim 1, in which said responsively powered means comprises a fluid pressure cylinder unit having an element operated in one direction only under fluid pressure from said source, said element being operatively connected to said actuator head to effect said releasable checking engagement of said collet members with said rod.
Claim 13
Dependent Claim 27 words
The safety device of claim 11, in which said operated element of said cylinder unit is spring-returned in a direction opposite its direction of fluid pressure operation.
Claim 14
Dependent Claim 37 words
The safety device of claim 1, and further comprising means acting automatically on said one unit to cause a release of said collet members from checking engagement with said rod upon restoration of fluid pressure operating power.

References Cited (Backward Citations)

FR1103862A Cited
US3096075A Cited
US3695144A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1977-01-07 1977-07-09 1978-01-08 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1981-01-07 1981-07-09 1982-01-08 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1985-01-07 1985-07-09 1986-01-08 $7700.00 Window Closed / Lapsed

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