Patent US3752327A successfully refreshed from Google Patents.
US3752327A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Multiple stage crane boom
Assignee: Hyster Co
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Filing: 1971-04-29
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Granted: 1973-08-14
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Expires: 1991-04-29
Abstract
Abstract A multiple stage crane boom has a vertically pivotable outer stage, a movable intermediate stage telescoping within the outer stage and a movable inner stage telescoping within the intermediate stage. A material-handling device is raised and lowered with respect to the outer end of the inner stage by a winch-powered cable. The boom is extended and retracted through simultaneous extension and retraction of the intermediate and inner stages by separate but simultaneously energized hydraulic cylinders. These cylinders are mounted and hydraulically interconnected in a manner which eliminates the need for extensible hydraulic hoses between the cylinders and the fluid pressure source. A cable-phasing arrangement interconnecting the stages provides in conjunction with the cylinders a boost to ensure proper phasing movement of the movable stages upon extension and retraction should friction tend to restrain one of such stages upon application of hydraulic power to the cylinders.
Inventors
- 👤 J Olson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 14:17
CPC Classifications
B; B66; B66C; B66C23/00; B66C23/62; B66C23/64; B66C23/70; B66C23/701
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
481 words
A multiple stage extensible and retractable boom for a crane comprising: a first outer boom stage, a second intermediate boom stage extendible and retractable relative to said and telescoping within said first boom stage, a third inner boom stage extendible and retractable relative to and telescoping within said second boom stage, a first reversible fluid cylinder means for extending and retracting said second boom stage relative to said first stage, a second reversible fluid cylinder means for extending and retracting said third boom stage relative to said second stage, said first and second cylinder means being operable at the same time for simultaneous extension and retraction of said second stage relative to said first stage and said third stage relative to said second stage, and flexible cable-phasing booster means interconnecting said first, second and third stages in a manner so as to ensure that upon simultaneous operation of both said cylinder means to extend said second and third stages and upon extension of one of said second and third stages, the other of said second and third stages will also extend at the same time, said first and second cylinder means having their extension sides hydraulically interconnected and their retraction sides hydraulically interconnected, with the extension and retraction sides of said first cylinder means only being directly connectable to a source of fluid pressure, said first cylinder means having a piston rod connected to said first stage and a cylinder portion connected to said second stage, said second cylinder means having a piston rod connected to said second stage and a cylinder portion connected to said third stage, a first fluid passage means leading from selective communication with said source and extending axially through the piston rod of said first cylinder means into communication with the retraction side of said first cylinder means, a second fluid passage means extending from the retraction side of said first cylinder means axially through the piston rod of said second cylinder means and into communication with a retraction side of said second cylinder means, third fluid passage means extending from selective communication with said source axially through the piston rod and into communication with an extension side of said first cylinder means, fourth fluid passage means extending from the extension side of said first cylinder means axially through the piston rod of said second cylinder means into communication with the extension side of said second cylinder means, said cable-phasing means including flexible cable means fixed at one point to an outer portion of said first stage, then in succession passing over a sheave means on an inner end portion of said second stage, fixed to said third stage at a second point inwardly of the outer end of said second stage, passing over a second sheave at an outer end portion of said second stage and fi4ed at a third point to said first stage.
Claim 2
Dependent Claim
481 words
A multiple stage extensible and retractable boom for a crane comprising: a first outer boom stage, a second intermediate boom stage extendible and retractable relative to said and telescoping within said first boom stage, a third inner boom stage extendible and retractable relative to and telescoping within said second boom stage, a first reversible fluid cylinder means for extending and retracting said second boom stage relative to said first stage, a second reversible fluid cylinder means for extending and retracting said third boom stage relative to said second stage, said first and second cylinder means being operable at the same time for simultaneous extension and retraction of said second stage relative to said first stage and said third stage relative to said second stage, and flexible cable-phasing booster means interconnecting said first, second and third stages in a manner so as to ensure that upon simultaneous operation of both said cylinder means to extend said second and third stages and upon extension of one of said second and third stages, the other of said second and third stages will also extend at the same time, said first and second cylinder means having their extension sides hydraulically interconnected and their retraction sides hydraulically interconnected, with the extension and retraction sides of said first cylinder means only being directly connectable to a source of fluid pressure, said first cylinder means having a piston rod connected to said first stage and a cylinder portion connected to said second stage, said second cylinder means having a piston rod connected to said second stage and a cylinder portion connected to said third stage, a first fluid passage means leading from selective communication with said source and extending axially through the piston rod of said first cylinder means into communication with the retraction side of said first cylinder means, a second fluid passage means extending from the retraction side of said first cylinder means axially through the piston rod of said second cylinder means and into communication with a retraction side of said second cylinder means, third fluid passage means extending from selective communication with said source axially through the piston rod and into communication with an extension side of said first cylinder means, fourth fluid passage means extending from the extension side of said first cylinder means axially through the piston rod of said second cylinder means into communication with the extension side of said second cylinder means, said cable-phasing means including flexible cable means fixed at one point to an outer portion of said first stage, then in succession passing over a sheave means on an inner end portion of said second stage, fixed to said third stage at a second point inwardly of the outer end of said second stage, passing over a second sheave at an outer end portion of said second stage and fi4ed at a third point to said first stage.
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) | 1976-08-13 | 1977-02-12 | 1977-08-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-08-13 | 1981-02-12 | 1981-08-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-08-13 | 1985-02-12 | 1985-08-14 | $7700.00 | Window Closed / Lapsed |