Patent US3708937A successfully refreshed from Google Patents.
US3708937A
Expired / Lapsed
US
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Trapezoidal telescoping crane boom
Assignee: Kidde Inc
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Filing: 1970-09-28
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Granted: 1973-01-09
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Expires: 1990-09-28
Abstract
Abstract A crane boom comprises plural extensible and retractable telescoping sections each of which is trapezoidal in cross section. The trapezoidal cross sectional shape imparts to a boom of given weight greater lifting capacity or longitudinal rigidity and greater lateral stability than any other cross sectional shape. The trapezoidal cross section allows for a much more efficient placement of wear pads between boom sections and web stiffeners on the sides and bottoms of the sections. Adequate internal space is provided for boom extending and retracting means whether hydraulic or mechanical.
Inventors
- 👤 R Sterner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 19:10
CPC Classifications
B; B66; B66C; B66C23/00; B66C23/62; B66C23/64; B66C23/70; B66C23/701; B66C23/705
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
189 words
A telescoping crane boom comprising a base section for the boom having means to pivot it about one end thereof, at least one additional extensible and retractable boom section telescopically engaged within the base section with means connected thereto adapted to load only the outer free end of the crane boom, power means to extend and retract the telescoping boom, all sections of the telescoping boom being trapezoidal in transverse cross section and including upwardly converging side webs, a relatively narrow top plate secured to the side webs and a relatively wide bottom plate unit secured to the side webs, a reinforcement for the top plate of at least the base section of the boom adjacent the forward end of the base section to resist stresses produced thereon by extension and loading of the next forwardmost boom section having upper wear pads bearing against the top plate of the base section, and said reinforcement comprising an overlayplate mounted on said top plate, and a pair of side reinforcing bars adjacent the overlay plate and near the tops of the side webs and secured thereto and to said top plate.
Claim 2
Dependent Claim
189 words
A telescoping crane boom comprising a base section for the boom having means to pivot it about one end thereof, at least one additional extensible and retractable boom section telescopically engaged within the base section with means connected thereto adapted to load only the outer free end of the crane boom, power means to extend and retract the telescoping boom, all sections of the telescoping boom being trapezoidal in transverse cross section and including upwardly converging side webs, a relatively narrow top plate secured to the side webs and a relatively wide bottom plate unit secured to the side webs, a reinforcement for the top plate of at least the base section of the boom adjacent the forward end of the base section to resist stresses produced thereon by extension and loading of the next forwardmost boom section having upper wear pads bearing against the top plate of the base section, and said reinforcement comprising an overlayplate mounted on said top plate, and a pair of side reinforcing bars adjacent the overlay plate and near the tops of the side webs and secured thereto and to said top plate.
Claim 3
Dependent Claim
25 words
The structure of claim 1, and plural longitudinally spaced web stiffeners secured to said side webs of at least said base section of the boom.
Claim 4
Dependent Claim
19 words
The structure of claim 2, and additional transverse longitudinally spaced web stiffeners for said bottom plate unit secured thereto.
Claim 5
Dependent Claim
51 words
The structure of claim 3, and a pair of longitudinal side reinforcing bars extending along the lower corners of at least said base section of the boom and secured to said side and bottom web stiffeners, said side webs and bottom plate unit formed of relatively thin gage material for lightness.
Claim 6
Dependent Claim
28 words
The structure of claim 4, and all of said web stiffeners comprising channel bars having their open sides facing and abutting the webs to which they are welded.
Claim 7
Dependent Claim
159 words
A telescoping crane boom comprising a base section for the boom having means to pivot it about one end thereof, at least one additional extensible and retractable boom section telescopically engaged within the base section with means connected thereto adapted to load only the outer free end of the crane booM, power means to extend and retract the telescoping boom, all sections of the telescoping boom being trapezoidal in transverse cross section and including upwardly converging side webs, a relatively narrow top plate secured to the side webs and a relatively wide bottom plate unit secured to the side webs, a pair of laterally spaced wear elements on the bottom plate unit of at least said base section near the forward end thereof to receive directly the bottom plate unit of the next forwardmost additional boom section, and said wear elements disposed directly under the side webs of said next forwardmost additional boom section for transmitting forces directly thereto.
Claim 8
Dependent Claim
159 words
A telescoping crane boom comprising a base section for the boom having means to pivot it about one end thereof, at least one additional extensible and retractable boom section telescopically engaged within the base section with means connected thereto adapted to load only the outer free end of the crane booM, power means to extend and retract the telescoping boom, all sections of the telescoping boom being trapezoidal in transverse cross section and including upwardly converging side webs, a relatively narrow top plate secured to the side webs and a relatively wide bottom plate unit secured to the side webs, a pair of laterally spaced wear elements on the bottom plate unit of at least said base section near the forward end thereof to receive directly the bottom plate unit of the next forwardmost additional boom section, and said wear elements disposed directly under the side webs of said next forwardmost additional boom section for transmitting forces directly thereto.
Claim 9
Dependent Claim
46 words
The structure of claim 6 in which the cross sectional height of any boom section is unity and the width of said top plate is from 0.35 to 0.6 of unity and the width of said bottom plate unit is from 0.8 to 1.1 of unity.
Claim 10
Dependent Claim
70 words
The structure of claim 6, and a pair of upper wear elements interposed between the top plates of the two boom sections and being located substantially directly above side side webs of the next forwardmost additional boom section for transmitting forces directly thereto whereby the side webs function substantially as columns to absorb said forces, and means to retain the upper wear elements on the next additional forwardmost boom section.
Claim 11
Dependent Claim
63 words
A telescopic crane boom as set forth in claim 6 in which said bottom plate unit of at least one of said boom sections includes a pair of longitudinal reinforcing bars extending along the lower corners of the boom section connected beneath the side webs thereof, and a bottom web of relatively thin gage material connected between said pair of longitudinal reinforing bars.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-01-09 | 1976-07-10 | 1977-01-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-01-09 | 1980-07-10 | 1981-01-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-01-09 | 1984-07-10 | 1985-01-09 | $7700.00 | Window Closed / Lapsed |