US3642148A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Device for achieving permanent equilibration in tower cranes
Assignee: Richier SA
•
Filing: 1970-05-21
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Granted: 1972-02-15
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Expires: 1990-05-21
Abstract
Abstract A device for obtaining permanent equilibration in tower cranes of the type including a load jib, over which a carriage fitted with a lifting hook travels, and a jib over which a carriage carrying a counterweight is adapted to be shifted, said device including in combination: means for measuring the moment resulting from the weight of the load, on the one hand, and from the position of the load carriage on the jib, on the other hand, means for shifting the counterweight carrier on the corresponding jib, and means for increasing the duration of the loading operation in order to enable the counterweight carrier to move only slowly and progressively as the load moment varies, without any disorderly motions.
Inventors
- 👤 Pierre Durand
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 12:36
CPC Classifications
B; B66; B66C; B66C9/00; B66C9/14; B66C23/00; B66C23/62; B66C23/72; B66C2700/00; B66C2700/03; B66C2700/0385; B66C2700/0392
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
178 words
A device for obtaining permanent equilibration in tower cranes of the type including a load jib, a carriage fitted with a load-lifting hook, a winding hoist cable connected at its free end to said carriage for imparting movement to the latter over said jib, a second jib, a carriage supporting a counterweight adapted to be shifted over said second jib, comprising the combination of means for measuring the moment resulting from the weight of the load on the one hand, and from the position of the load carriage on the load jib on the other hand, means for shifting the counterweight-supporting carriage on said second jib, and means for increasing the duration of the loading operation to enable said last-mentioned carriage to move slowly and progressively only in response to variations in the load moment while eliminating sudden motions thereof, the increase in the duration of the loading operation being in response to an increase in the length of hoist cable unwound from its winding end, and a device for temporarily slackening the tension in said hoist cable.
Claim 2
Independent Claim
178 words
A device for obtaining permanent equilibration in tower cranes of the type including a load jib, a carriage fitted with a load-lifting hook, a winding hoist cable connected at its free end to said carriage for imparting movement to the latter over said jib, a second jib, a carriage supporting a counterweight adapted to be shifted over said second jib, comprising the combination of means for measuring the moment resulting from the weight of the load on the one hand, and from the position of the load carriage on the load jib on the other hand, means for shifting the counterweight-supporting carriage on said second jib, and means for increasing the duration of the loading operation to enable said last-mentioned carriage to move slowly and progressively only in response to variations in the load moment while eliminating sudden motions thereof, the increase in the duration of the loading operation being in response to an increase in the length of hoist cable unwound from its winding end, and a device for temporarily slackening the tension in said hoist cable.
Claim 3
Dependent Claim
145 words
A device as claimed in claim 1, wherein the device slackening the tension of the cable temporarily is hydraulic, and comprises a multistrand block interposed between the fixed point of the hoist cable and the lifting hook, the first set of sheaves of said block being fast, while the second set of sheaves is mounted on a movable support connected to the fast support of the first set of sheaves by a single action hydraulic jack, the working chamber of said jack being connected to at least one oleopneumatic accumulator adjusted to a given pressure, in order that, at the time of the loading operation, the tension of the cable causes first the shifting of the movable support of said second set of sheaves towards said first set of sheaves, and then, only when said support has completed its travel, the elevation of the load.
References Cited (Backward Citations)
US446043A
Cited
US2413701A
Cited
FR1135807A
Cited
FR1212461A
Cited
US3240353A
Cited
US3381826A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-02-14 | 1975-08-16 | 1976-02-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-02-14 | 1979-08-16 | 1980-02-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-02-14 | 1983-08-16 | 1984-02-15 | $7700.00 | Window Closed / Lapsed |