Patent US3841494A successfully refreshed from Google Patents.
US3841494A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Sequenced crane boom
Assignee: FMC Corp
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Filing: 1972-08-02
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Granted: 1974-10-15
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Expires: 1992-08-02
Abstract
Abstract The invention concerns a hydraulically operated telescoping crane boom which is sequenced by means of a latch mechanism and sequencing valves such that the boom sections are automatically extended in order starting with the innermost section first. During retraction, the sequence is reversed; the outermost section being retracted first. Alternate forms are disclosed adding a manually operated section to the automatically operated boom and an entirely manually operated boom embodying the specific sequencing.
Inventors
- 👤 P Chalupsky
- 👤 O Nephew
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 01:20
CPC Classifications
B; B66; B66C; B66C23/00; B66C23/06; B66C23/62; B66C23/64; B66C23/70; B66C23/701; B66C23/705
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
214 words
In a telescoping boom having an outer fixed section, movable intermediate and inner boom sections, means for connecting a first power cylinder between the outer and intermediate boom sections for extending the latter, means for connecting a second power cylinder between the intermediate and inner boom sections for extending the latter, each of the cylinders including telescoping rod and case elements defining cavities effective to cause extension and retraction of the cylinders in response to fluid pressure, fluid supply means for directing fluid under pressure successively through the first and second cylinders, wherein the improvement comprises piston means in the extension cavity of said first cylinder having a first effective piston area exposed to fluid pressure from said supply means and an auxiliary piston, said second cylinder having piston means of larger effective area than the first area of said first cylinder for causing said second cylinder and intermediate boom section to extend before said first cylinder and inner boom section extend in response to fluid pressure, and valve means in said first cylinder piston means for exposing the auxiliary piston area to fluid pressure to augment said first area and cause extension of said inner boom section when the fluid pressure reaches a predetermined value after said intermediate boom section has been extended.
Claim 2
Dependent Claim
214 words
In a telescoping boom having an outer fixed section, movable intermediate and inner boom sections, means for connecting a first power cylinder between the outer and intermediate boom sections for extending the latter, means for connecting a second power cylinder between the intermediate and inner boom sections for extending the latter, each of the cylinders including telescoping rod and case elements defining cavities effective to cause extension and retraction of the cylinders in response to fluid pressure, fluid supply means for directing fluid under pressure successively through the first and second cylinders, wherein the improvement comprises piston means in the extension cavity of said first cylinder having a first effective piston area exposed to fluid pressure from said supply means and an auxiliary piston, said second cylinder having piston means of larger effective area than the first area of said first cylinder for causing said second cylinder and intermediate boom section to extend before said first cylinder and inner boom section extend in response to fluid pressure, and valve means in said first cylinder piston means for exposing the auxiliary piston area to fluid pressure to augment said first area and cause extension of said inner boom section when the fluid pressure reaches a predetermined value after said intermediate boom section has been extended.
Claim 3
Dependent Claim
31 words
The boom of claim 1 wherein said first cylinder piston means includes sequencing valve means for preventing retraction of the inner boom section until the intermediate boom section has been retracted.
Claim 4
Dependent Claim
39 words
The boom of claim 2 wherein said first cylinder piston means includes a relief valve effective between said auxiliary and first cavities to permit escape of fluid from said auxiliary cavity allowing complete retraction of said intermediate boom section.
Claim 5
Dependent Claim
38 words
The boom of claim 3 wherein one of said telescoping elements of each of said cylinders includes pilot check means for preventing release of fluid from its extension cavity until fluid pressure is applied to its retraction cavity.
Claim 6
Dependent Claim
61 words
The boom of claim 3 wherein said cylinder connecting means for each cylinder includes diametrically opposed sets spaced lugs disposed to receive vertical pins between them, and means on said movable boom sections defining bosses for retaining said vertical pins and for cooperating with said pins and lugs to transmit extension and retracting forces between said boom sections and said cylinders.
Claim 7
Dependent Claim
47 words
The boom of claim 5 wherein said spacing between said lugs is defined by straight vertical surfaces, and said vertical pins have a diameter less than said spacing for permitting relative sliding motion between said lugs and said vertical pins upon deflection of the boom under load.
Claim 8
Dependent Claim
19 words
The boom of claim 5 wherein said lugs are located on the rear portion of the cylinder case elements.
Claim 9
Dependent Claim
125 words
The boom of claim 5 wherein an auxiliary boom section is telescopingly received within said inner boom section, a set of apertures in said outer intermediate and inner boom sections in alignment for inserting said vertical pins associated with said second cylinder when said boom sections are retracted, connector means secured to the outward end of said second cylinder, alignable openings in said connector means auxiliary and inner boom sections, a first removable pin insertable through alignable openings in said connector means and said auxiliary section to drivingly connect said second cylinder to said auxiliary boom section and retaining means for retaining said vertical pins in a partially inserted position to disengage said second cylinder and lock said inner intermediate and outer boom sections together.
Claim 10
Dependent Claim
36 words
The boom of claim 8 wherein a second removable pin is Insertable in alignable openings to lock said inner and auxiliary boom sections together when said auxiliary section is either in an extended or retracted position.
References Cited (Backward Citations)
DE1282268B
Cited
US3396852A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-10-14 | 1978-04-15 | 1978-10-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-10-14 | 1982-04-15 | 1982-10-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-10-14 | 1986-04-15 | 1986-10-15 | $7700.00 | Window Closed / Lapsed |