US3750846A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Lazy tong type boom structure with extension aid
Assignee: Del Mar Engineering Laboratories
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Filing: 1971-12-01
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Granted: 1973-08-07
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Expires: 1991-12-01
Abstract
Abstract A boom structure including a plurality of crossed links having their centers and ends pivotally connected to define a lazy tong structure includes a compression spring positioned to exert a force between the next to last and last links making up the lazy tong structure when the structure is in collapsed position to aid extension of the structure. The spring has one end secured close to the central point of the next to last link and its other end is free. The opposing last link portion includes a guiding cone for receiving the free end of the compression spring when the structure is collapsed. When the lazy tong structure is extended, the compression spring effects initial extension of the next to last and last links while the initial crossed links at the base of the boom are separated by the driving force for extending the structure. A smooth unfolding of the respective links can thus be realized.
Inventors
- 👤 T Huxley
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 13:43
CPC Classifications
B; B66; B66F; B66F11/00; B66F11/04; B66F11/042; A; A01; A01D; A01D46/00; A01D46/20; B66F11/044; E; E04; E04G; E04G1/00; E04G1/18; E04G1/22
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
156 words
A boom structure comprising: a plurality of crossed links having their centers and ends pivotally connected to define a lazy tong structure, a first end of said structure constituting the base of said boom and the second end terminating in a load carrying means; and a force providing means secured to the central portion of a next to last link pivoted to the next to last center pivot point, and oriented to exert a force on the central portion of a last link pivoted to the last center pivot point when the structure is collapsed, the next to last and last center pivot points being closest to each other in the collapsed position, said force providing means being free of the last link after a given partial extension has taken place, said extension being sufficient to enable the unfolding load, transmitted through the links of the lazy tong structure, to fully extend the last crossed links.
Claim 2
Dependent Claim
156 words
A boom structure comprising: a plurality of crossed links having their centers and ends pivotally connected to define a lazy tong structure, a first end of said structure constituting the base of said boom and the second end terminating in a load carrying means; and a force providing means secured to the central portion of a next to last link pivoted to the next to last center pivot point, and oriented to exert a force on the central portion of a last link pivoted to the last center pivot point when the structure is collapsed, the next to last and last center pivot points being closest to each other in the collapsed position, said force providing means being free of the last link after a given partial extension has taken place, said extension being sufficient to enable the unfolding load, transmitted through the links of the lazy tong structure, to fully extend the last crossed links.
Claim 3
Dependent Claim
57 words
The structure of claim 1, in which said force providing means comprises a compression spring having one end secured to said next to last link and its other end free of any connection, said last link including an opposing guide cone for receiving the free end of said compression spring when said lazy tong structure is collapsed.
Claim 4
Dependent Claim
83 words
The structure of claim 1, in which said boom structure includes an additional plurality of crossed links having their centers and ends pivotally connected to define a lazy tong structure parallel to the first plurality of links, the respective pivot points including common cross-rods, said force providing means exerting a separating force between the links pivoted to the next to last and last cross-rods defining the next to last and last center pivot points of the lazy tongs respectively, when in collapsed position.
Claim 5
Dependent Claim
54 words
The structure of claim 3, in which said force provided means comprises a pair of compression springs secured at first ends respectively to the central portions of the next to last links of the lazy tong structures, the other ends of the springs being free when the lazy tong structures are in extended positions.
Claim 6
Dependent Claim
41 words
The structure of claim 4, in which the central portions of the last links include a pair of guide cones positioned to receive and compress the free ends of said pair of springs respectively when the lazy tong structures are collapsed.
Claim 7
Dependent Claim
138 words
A collapsible boom comprising a plurality of pairs of crossed links including first means for pivotally attaching each pair of links to one another at the location of their crossings and second means for pivotally attaching the ends of each pair of links to the ends of an adjacent pair of links, a first pair of links adjacent one end of the boom and mounting said boom on a support means, a last pair of links, at the end of said boom opposite said first pair, for supporting a load carried by said boom, means for extending and retracting said boom by causing said pairs of links to pivot about said first attaching means, and means acting between at least two adjacent pairs of said links for preventing the complete retraction of said boom by said retracting means.
Claim 8
Dependent Claim
138 words
A collapsible boom comprising a plurality of pairs of crossed links including first means for pivotally attaching each pair of links to one another at the location of their crossings and second means for pivotally attaching the ends of each pair of links to the ends of an adjacent pair of links, a first pair of links adjacent one end of the boom and mounting said boom on a support means, a last pair of links, at the end of said boom opposite said first pair, for supporting a load carried by said boom, means for extending and retracting said boom by causing said pairs of links to pivot about said first attaching means, and means acting between at least two adjacent pairs of said links for preventing the complete retraction of said boom by said retracting means.
Claim 9
Dependent Claim
47 words
The boom of claim 6 wherein said preventing means also includes means for aiding in the extension of said boom by exerting a separating force between two of said pairs of links at substantially the location of the said first attaching means in each of said pairs.
Claim 10
Dependent Claim
27 words
The boom of claim 6 wherein said preventing means is located so as to act between said last pair of links and the next-to-the-last pair of links.
Claim 11
Dependent Claim
29 words
The boom of claim 8 wherein said preventing means also comprises means for exerting a separatiNg force between said last pair of links and the next-to-the-last pair of links.
Claim 12
Dependent Claim
40 words
The boom of claim 6 wherein said preventing means comprises spring means secured to one of said pairs of links adjacent said first attaching means thereof and acting against an adjacent pair of links adjacent said first attaching means thereof.
References Cited (Backward Citations)
US2471901A
Cited
US3470981A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-08-06 | 1977-02-05 | 1977-08-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-08-06 | 1981-02-05 | 1981-08-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-08-06 | 1985-02-05 | 1985-08-07 | $7700.00 | Window Closed / Lapsed |