US4016803A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Servo device
Assignee: Danfoss AS
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Filing: 1975-11-10
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Granted: 1977-04-12
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Expires: 1995-11-10
Abstract
Abstract The invention relates to a servo assembly having a stationary part including a housing, a movable member and a servo motor. Of primary interest is the stopping mechanism which includes a stop unit on the movable member and two pressure operated, vertically reciprocal stop members mounted in the housing. Two hydraulic circuits are provided with a first circuit for the two stop members and the second circuit for the servo motor. Throttle valving for the first circuit is provided between the two stop members and the housing. Prior to reaching a stopping position the stop unit on the movable member actuates a switch which relieves the pressure in the first circuit and causes one of the stop members to descend to an intermediate position where throttling occurs and the other stop member to descend to a final position where throttling may or may not occur. The throttling causes substantial braking of the movable member during a short distance of travel just prior to the stopping position being reached. A rib on the stop unit of the movable member is arranged to control the intermediate and final positions of the two vertically movable stop members.
Inventors
- 👤 Svend Ove Soby
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 21:31
CPC Classifications
B; B23; B23Q; B23Q15/00; B23Q15/20; B23Q15/22; B23Q15/24
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
256 words
A servo device comprising movable and stationary members, hydraulic servo motor means for moving said movable member along a path in either of two selected directions, a transversely extending stop unit attached to said movable member, a rib on said stop unit, fluid pressure operated first and second adjacently arranged stop members movable transversely relative to said path, said stop members jointly defining a recess having a width generally equal to the width of said rib for cooperating with said rib to prevent movement of said movable member, first valve and circuit means for supplying a working fluid to said servo motor means, said first circuit means having throttle valve means formed between said stationary member and at least one of said stop members for throttling the fluid flow from said first valve to said servo motor means, first switch means operated by said stop members to open said first valve when said stop members are in initial up positions and to close said first valve when both of said stop members are in final down positions resting on said stop unit, second valve and circuit means for moving each of said stop members to initial positions which clear said rib and actuate said first switch means, second switch means actuated by said stop unit for closing said second valve to cause said stop members to descend until one rests in an intermediate position on said rib wherein throttling occurs in said first circuit and the other rests in a final position on said stop unit.
Claim 2
Dependent Claim
256 words
A servo device comprising movable and stationary members, hydraulic servo motor means for moving said movable member along a path in either of two selected directions, a transversely extending stop unit attached to said movable member, a rib on said stop unit, fluid pressure operated first and second adjacently arranged stop members movable transversely relative to said path, said stop members jointly defining a recess having a width generally equal to the width of said rib for cooperating with said rib to prevent movement of said movable member, first valve and circuit means for supplying a working fluid to said servo motor means, said first circuit means having throttle valve means formed between said stationary member and at least one of said stop members for throttling the fluid flow from said first valve to said servo motor means, first switch means operated by said stop members to open said first valve when said stop members are in initial up positions and to close said first valve when both of said stop members are in final down positions resting on said stop unit, second valve and circuit means for moving each of said stop members to initial positions which clear said rib and actuate said first switch means, second switch means actuated by said stop unit for closing said second valve to cause said stop members to descend until one rests in an intermediate position on said rib wherein throttling occurs in said first circuit and the other rests in a final position on said stop unit.
Claim 3
Dependent Claim
29 words
A servo device according to claim 1 wherein said throttle valve means are in both of said stop members and connected to opposite sides of said servo motor means.
Claim 4
Dependent Claim
35 words
A servo device according to claim 1 wherein said throttle valve means includes ports in said stationary member and openings in said stop members which cooperate to throttle the flow in said first circuit means.
Claim 5
Dependent Claim
20 words
A servo device according to claim 3 including an adjusting member for varying the effect of said throttle valve means.
Claim 6
Dependent Claim
23 words
A servo device according to claim 1 including spring means for biasing said stop members towards final resting positions on said stop unit.
Claim 7
Dependent Claim
36 words
A servo device according to claim 1 wherein said second switch means includes tappet means mounted in said stationary member, said tappet means being actuatable upon being contacted by a leading edge of said stop unit.
Claim 8
Dependent Claim
40 words
A servo device according to claim 6 wherein said tappet means includes a plurality of tappets, said stop unit having grooves for receiving all but one of said tappets to allow only said one of said tappets to be actuated.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-04-11 | 1980-10-11 | 1981-04-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-04-11 | 1984-10-11 | 1985-04-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-04-11 | 1988-10-11 | 1989-04-12 | $7700.00 | Window Closed / Lapsed |