US3877544A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Stress balanced extendible boom structure
Assignee: Del Mar Engineering Laboratories
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Filing: 1973-07-13
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Granted: 1975-04-15
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Expires: 1993-07-13
Abstract
Abstract A lazy tong or scissor-type of extendible boom structure having one end mounted on a platform. The boom structure can be extended, elevated, and/or rotated independently by drive structure mounted on the platform and a load-carrying basket is mounted on the opposite end of the boom. The boom comprises a pair of parallel lazy tongs, each comprising pairs of beams which are pivoted to one another in scissorlike fashion, the pivoted beams opposite each other on the two lazy tongs forming one ''''bay.'''' Stress transmitting rigid structural cross members are fixed between the inner beams of each bay and similar cross members are nested at interference-free positions and between the outer beams of each bay to balance the torque within the pair of lazy tongs and prevent rotation of the beams and consequent twisting of the extended boom when an asymmetrical load is applied thereto, such as by an off-center load in the platform or basket or by the locating of the platform base in a nonhorizontal plane.
Inventors
- 👤 Fenwick Harris Mccollum
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 06:50
CPC Classifications
B; B66; B66F; B66F11/00; B66F11/04; B66F11/044
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
180 words
A boom for locating a basket suspended from the end thereof at a predetermined position in which an asymmetrical load may be applied to said boom comprising a pair of lazy tongs arranged in parallel relationship, each including a plurality of bays comprising an inner beam, an outer beam, means near the centers of said inner and outer beams for pivotally connecting them together, means interconnecting said pair of lazy tongs to prohibit rotation of said boom about the central axis thereof when an asymmetrical load is applied thereto by said basket, which load tends to extend one of said lazy tongs and retract the other comprising first torsion transmitting means fixed between the inner beams in each bay intermediate and pivot connection means and each end thereof and second torsion transmitting means fixed between the outer beams in each bay intermediate said pivot connection means and each end thereof, said first and second torsion transmitting means being so constructed as to have equal torsional spring rates, and means at the outermost bay for supporting and mounting a basket thereon.
Claim 2
Dependent Claim
180 words
A boom for locating a basket suspended from the end thereof at a predetermined position in which an asymmetrical load may be applied to said boom comprising a pair of lazy tongs arranged in parallel relationship, each including a plurality of bays comprising an inner beam, an outer beam, means near the centers of said inner and outer beams for pivotally connecting them together, means interconnecting said pair of lazy tongs to prohibit rotation of said boom about the central axis thereof when an asymmetrical load is applied thereto by said basket, which load tends to extend one of said lazy tongs and retract the other comprising first torsion transmitting means fixed between the inner beams in each bay intermediate and pivot connection means and each end thereof and second torsion transmitting means fixed between the outer beams in each bay intermediate said pivot connection means and each end thereof, said first and second torsion transmitting means being so constructed as to have equal torsional spring rates, and means at the outermost bay for supporting and mounting a basket thereon.
Claim 3
Dependent Claim
35 words
The boom of claim 1 including means acting only along the central axis of said boom for selective extension and retraction thereof regardless of whether said boom is subject to uniformly distributed or asymmetrical loads.
Claim 4
Dependent Claim
28 words
The boom of claim 1 including mounting means to which said boom is attached for support thereof, and independently actuatable means for elevating, rotating, and extending said boom.
Claim 5
Dependent Claim
197 words
A boom comprising a pair of lazy tongs forming a plurality of pivotally connected bays, each bay including a pair of parallel inner beams, one in each lazy tong, a pair of parallel outer beams, one in each lazy tong, and means pivotally connecting the inner beam and the outer beam of each lazy tong in each bay near the centers of said inner and outer beams, means for suspending support apparatus from the outermost bay of the boom, whereby asymmetrical loading may be imposed on the boom, thereby causing one lazy tong to tend to retract and the other to extend, a pair of first torsion transmitting means extending between the inner beams in each bay and fixed thereto to preVent rotation of said inner beams upon the application of asymmetrical loading forces to said support means, and a pair of second torsion transmitting means extending between the outer beams in each bay and fixed thereto to prevent rotation of said lazy tongs about the central axis of said boom upon the application of asymmetrical loading forces to said support means, said first and second means being so constructed as to have identical torsional spring rates.
Claim 6
Dependent Claim
197 words
A boom comprising a pair of lazy tongs forming a plurality of pivotally connected bays, each bay including a pair of parallel inner beams, one in each lazy tong, a pair of parallel outer beams, one in each lazy tong, and means pivotally connecting the inner beam and the outer beam of each lazy tong in each bay near the centers of said inner and outer beams, means for suspending support apparatus from the outermost bay of the boom, whereby asymmetrical loading may be imposed on the boom, thereby causing one lazy tong to tend to retract and the other to extend, a pair of first torsion transmitting means extending between the inner beams in each bay and fixed thereto to preVent rotation of said inner beams upon the application of asymmetrical loading forces to said support means, and a pair of second torsion transmitting means extending between the outer beams in each bay and fixed thereto to prevent rotation of said lazy tongs about the central axis of said boom upon the application of asymmetrical loading forces to said support means, said first and second means being so constructed as to have identical torsional spring rates.
Claim 7
Dependent Claim
37 words
The boom of claim 3 including a support means, guide means mounted on said support means, and means on the lowermost beam for cooperating with said guide means to control the extension and retraction of said boom.
Claim 8
Dependent Claim
165 words
In a boom comprising a pair of parallel lazy tongs, each includes a plurality of bays comprising an inner and outer beam, which support a work platform in suspension therefrom at the outer ends thereof and including apparatus for preventing the collapse of one lazy tongs and the extension of the other as a result of asymmetrical loading being applied to said boom, means for preventing the rotation of said boom about the central axis thereof as a result of torsion forces generated by said collapse and extension means comprising at least one torsion transmission member extending between and fixed to the outer beams in each bay of said boom, and at least one torsion transmission member extending between and fixed to the inner beams in each bay of said boom, the torsional spring rate of said lazy tong extension and collapse prevention means in any given bay being equal to the torsional spring rate of said boom rotation prevention means in the same bay.
Claim 9
Dependent Claim
165 words
In a boom comprising a pair of parallel lazy tongs, each includes a plurality of bays comprising an inner and outer beam, which support a work platform in suspension therefrom at the outer ends thereof and including apparatus for preventing the collapse of one lazy tongs and the extension of the other as a result of asymmetrical loading being applied to said boom, means for preventing the rotation of said boom about the central axis thereof as a result of torsion forces generated by said collapse and extension means comprising at least one torsion transmission member extending between and fixed to the outer beams in each bay of said boom, and at least one torsion transmission member extending between and fixed to the inner beams in each bay of said boom, the torsional spring rate of said lazy tong extension and collapse prevention means in any given bay being equal to the torsional spring rate of said boom rotation prevention means in the same bay.
Claim 10
Dependent Claim
55 words
The boom of claim 6 including a support means upon which the inner ends of the boom is mounted, and means on said support means for exerting forces along the central axis of said boom to uniformly extend and retract the latter regardless of asymmetry of uniformity of loading of said boom by said platform.
Claim 11
Dependent Claim
72 words
The boom of claim 7 wherein said force exerting means comprises a single drive means and means, situated generally along the central axis of said boom, connecting said single drive means to a cross member, and a cross member in the lowermost bay of said boom pivotally attached to the lazy tong on each side of the boom for transmitting extension and retraction forces from said connecting means to said lazy tongs.
Claim 12
Dependent Claim
26 words
The device of claim 6 including means mounted on said support means for independently altering the rotational location of said boom relative to said support means.
Claim 13
Dependent Claim
27 words
The device of claim 6 including means mounted on said support means for independently altering the angle of elevation of said boom relative to said support means.
Claim 14
Dependent Claim
188 words
In a boom comprising a pair of parallel lazy tong, each including a plurality of bays comprising an inner and outer beam, from which a load bearing member is suspended at the outer end of the boom, which load bearing member may subject one lazy tong to collapsing forces and the other lazy tong to extension forces as a result of asymmetrical force loading, the method of prohibiting such non-uniform movement of the lazy tongs while also prohibiting the rotation of the outer end of the boom relative to the inner end thereof about the central axis of the boom comprising the steps of transmitting torsional forces exerted on the inner beam of each lazy tong in each bay to the opposite inner beam in the other lazy tong in the same bay via members having a first length and a first total spring rate, and transmitting torsional forces exerted on the outer beam of each lazy tong in each bay to the opposite outer beam in the other lazy tong in the same bay via members having a second, longer length but said first total spring rate.
Claim 15
Dependent Claim
188 words
In a boom comprising a pair of parallel lazy tong, each including a plurality of bays comprising an inner and outer beam, from which a load bearing member is suspended at the outer end of the boom, which load bearing member may subject one lazy tong to collapsing forces and the other lazy tong to extension forces as a result of asymmetrical force loading, the method of prohibiting such non-uniform movement of the lazy tongs while also prohibiting the rotation of the outer end of the boom relative to the inner end thereof about the central axis of the boom comprising the steps of transmitting torsional forces exerted on the inner beam of each lazy tong in each bay to the opposite inner beam in the other lazy tong in the same bay via members having a first length and a first total spring rate, and transmitting torsional forces exerted on the outer beam of each lazy tong in each bay to the opposite outer beam in the other lazy tong in the same bay via members having a second, longer length but said first total spring rate.
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) | 1978-04-14 | 1978-10-14 | 1979-04-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-04-14 | 1982-10-14 | 1983-04-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-04-14 | 1986-10-14 | 1987-04-15 | $7700.00 | Window Closed / Lapsed |