US3876222A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Tension limiting apparatus
Assignee: PRODUCTION TECHNOLOGIES Inc A CORP OF OR
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Filing: 1973-09-05
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Granted: 1975-04-08
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Expires: 1993-09-05
Abstract
Abstract There is disclosed a tension limiting device which is operative to de-energize a winch when tension in the winch line either exceeds a predetermined value or falls below another predetermined value. The device is designed for use in a trailer in which the frame may be raised or lowered relative to the ground. The device incorporates a first lever connected to the winch line which is opposed by a second and third spring biased levers. Suitable limit switches are placed in the path of movement of one of the levers to de-energize the winch.
Inventors
- 👤 Roland H Thorsell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 06:44
CPC Classifications
B; B66; B66D; B66D1/00; B66D1/54; B66D1/58; B62; B62D; B62D53/00; B62D53/04; B62D53/06; B62D53/061; B62D53/062
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
269 words
Apparatus comprising an elongate tensile element and means for changing the stress in the element in both tensioning and relaxing directions; and means responsive to a first low level and a first higher level tension in the element for deactivating the stress changing means in the relaxing and tensioning directions respectively including a frame; a first member movably mounted on the frame and connected to the element for moving the first member in a first direction in accordance with tension in the element; means, including a second member movably mounted on the frame for biasing the first member in a second opposite direction at a first small force upon application of the first low level of tension to the element and for biasing the first member in the second direction at a second larger force upon application of the first higher level of tension to the element; a switch actuator carried by one of said members defining a path of movement extending in the first and second directions, the actuator having a neutral position intermediate the path; a first low tension and a second high tension limit switch disposed in the path of movement in the second and first directions respectively from the neutral position; the first member biasing means including means biasing the second member against the first member; and a third member movably mounted on the frame, and means inoperative upon the application of the first low level of tension to the element and operative upon the application of the first higher level of tension to the element for biasing the third member against the first member.
Claim 2
Dependent Claim
269 words
Apparatus comprising an elongate tensile element and means for changing the stress in the element in both tensioning and relaxing directions; and means responsive to a first low level and a first higher level tension in the element for deactivating the stress changing means in the relaxing and tensioning directions respectively including a frame; a first member movably mounted on the frame and connected to the element for moving the first member in a first direction in accordance with tension in the element; means, including a second member movably mounted on the frame for biasing the first member in a second opposite direction at a first small force upon application of the first low level of tension to the element and for biasing the first member in the second direction at a second larger force upon application of the first higher level of tension to the element; a switch actuator carried by one of said members defining a path of movement extending in the first and second directions, the actuator having a neutral position intermediate the path; a first low tension and a second high tension limit switch disposed in the path of movement in the second and first directions respectively from the neutral position; the first member biasing means including means biasing the second member against the first member; and a third member movably mounted on the frame, and means inoperative upon the application of the first low level of tension to the element and operative upon the application of the first higher level of tension to the element for biasing the third member against the first member.
Claim 3
Dependent Claim
33 words
The apparatus of claim 1 wherein the means biasing the second member includes a spring connected between the frame and the second member for continuously biasing the second member against the first member.
Claim 4
Dependent Claim
44 words
The apparatus of claim 1 wherein the means biasing the third member comprises a spring biasing the third member continuously in the second direction and an abutment for engaging the third member and preventing movement thereof in the second direction beyond a predetermined limit.
Claim 5
Dependent Claim
13 words
The apparatus of claim 3 wherein each of the members comprises a lever.
Claim 6
Dependent Claim
59 words
The apparatus of claim 4 comprising means pivotally mounting the first and third levers to the frame and means pivotally mounting the second lever to the third lever, the means biasing the second and third levers comprising a spring connected between the frame and the second lever for continuously biasing the second and third levers in the second direction.
Claim 7
Dependent Claim
27 words
The apparatus of claim 4 wherein the pivotal connections of the first, second and third levers are generally aligned in the neutral position of the switch actuator.
Claim 8
Dependent Claim
48 words
The apparatus of claim 4 wherein the distance between the third lever pivotal connection and the point of engagement of the first and third levers is substantially less than the distance between the second lever pivotal connection and the point of engagement of the first and second levers.
Claim 9
Dependent Claim
24 words
The apparatus of claim 4 comprising a pair of elongate elements and means pivotally connecting the pair of elongate elements to the first lever.
Claim 10
Dependent Claim
27 words
The apparatus of claim 8 wherein the pivotal connecting means comprises means for equalizing tension in the pair of elongate elements upon application of unequal tension thereto.
Claim 11
Dependent Claim
62 words
The apparatus of claim 9 wherein the connecting means includes first and second ears and the equalizing means includes first and second connecting levers pivotally mounted to the first and second ears respectively, the elongate elements being separately connected to the first and second connecting levers away from the pivotal mounting thereof, and means linking the first and second connecting levers together.
Claim 12
Dependent Claim
87 words
The apparatus of claim 6 further comprising a vehicle including a frame; means for movably supporting the frame on an underlying surface; means adjustably mounting the movable support means on the frame between an upper position and a lower position in which the frame rests on the underlying surface; and means for moving the support means relative to the frame including the elongate element and the means for changing the stress in the elongate element, the elongate element being interengaged between the frame and the mounting means.
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) | 1978-04-07 | 1978-10-07 | 1979-04-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-04-07 | 1982-10-07 | 1983-04-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-04-07 | 1986-10-07 | 1987-04-08 | $7700.00 | Window Closed / Lapsed |