US3633460A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Extension means of a multistage extensible boom
Assignee: Tadano Ltd
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Filing: 1969-12-11
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Granted: 1972-01-11
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Expires: 1989-12-11
Abstract
Abstract The present invention discloses an extension means of a multistage extensible boom having more than three boom members and a plurality of hydraulic cylinders and characterized in that each of the hydraulic cylinders is provided with a compressed oil chamber on its extending side and a compressed oil chamber on its retracting side, both of the compressed oil chambers are in serial communication with each other, one of the hydraulic cylinders is connected to the oil pressure supply and discharge circuit, and a plurality of changeover valves controllable by the oil pressure or solenoids are interconnected to respective oil pressure supply circuits connecting the preceding hydraulic cylinder with the succeeding hydraulic cylinder, so that the oil pressure is easily controlled for successively and in regular sequence to actuate respective boom members to an extending or retracting position. A unitary control valve or a plurality of control valves is provided for operating the changeover valves, thereby providing simplicity and accuracy in operation.
Inventors
- 👤 Kazuhiro Ohniwa
- 👤 Seiiti Ishikawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 06:50
CPC Classifications
F; F15; F15B; F15B11/00; F15B11/16; F15B11/20; F15B11/205; B; B66; B66C; B66C23/00; B66C23/62; B66C23/64; B66C23/70; B66C23/701; B66C23/705
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
157 words
In an extension means of a multistage extensible boom having more than three boom members telescopically extensibly connected to each other and a plurality of hydraulic cylinders associated with respective boom members and extending longitudinally from a base portion of said multistage extensible boom to a top portion thereof spaced longitudinally from the base portion, which comprises a compressed oil chamber provided on an extending side of a respective hydraulic cylinder and a compressed oil chamber provided on a retracting side thereof; both of said oil chambers being in serial communication with each other; one of said hydraulic cylinders positioned closest to the base portion of said boom being connected to an oil pressure supply and discharge circuit; and a plurality of changeover valves controllable by one of oil pressure and solenoids and each connected to said oil pressure supply and discharge circuits and each connecting a preceding said hydraulic cylinder with a succeeding said hydraulic cylinder.
Claim 2
Dependent Claim
157 words
In an extension means of a multistage extensible boom having more than three boom members telescopically extensibly connected to each other and a plurality of hydraulic cylinders associated with respective boom members and extending longitudinally from a base portion of said multistage extensible boom to a top portion thereof spaced longitudinally from the base portion, which comprises a compressed oil chamber provided on an extending side of a respective hydraulic cylinder and a compressed oil chamber provided on a retracting side thereof; both of said oil chambers being in serial communication with each other; one of said hydraulic cylinders positioned closest to the base portion of said boom being connected to an oil pressure supply and discharge circuit; and a plurality of changeover valves controllable by one of oil pressure and solenoids and each connected to said oil pressure supply and discharge circuits and each connecting a preceding said hydraulic cylinder with a succeeding said hydraulic cylinder.
Claim 3
Dependent Claim
204 words
In an extension means of a multistage extensible boom having more than three boom members telescopically extensibly connected to each other and a plurality of hydraulic cylinders associated with respective boom members and extending longitudinally from a base portion of said multistage extensible boom to a top portion thereof spaced longitudinally from the base portion, which comprises a compressed oil chamber provided on an extending side of a respective hydraulic cylinder and a compressed oil chamber provided on a retracting side thereof; both of said oil chambers being in serial communication with each other; one of said hydraulic cylinders positioned closest to the base portion of said boom being connected to an oil pressure supply and discharge circuit; a plurality of changeover valves controllable by one of an oil pressure and solenoids and each connected to working-pressure supply and exhaust circuits connecting a preceding hydraulic cylinder with a succeeding hydraulic cylinder; control circuits connected to each of said changeover valves controllable by one of oil pressure and solenoids; and a unitary chAngeover valve or switching means connected to each of said control circuits; said unitary changeover valve or switching means being arranged for selectively operating each of said changeover valves to a desired position.
Claim 4
Dependent Claim
204 words
In an extension means of a multistage extensible boom having more than three boom members telescopically extensibly connected to each other and a plurality of hydraulic cylinders associated with respective boom members and extending longitudinally from a base portion of said multistage extensible boom to a top portion thereof spaced longitudinally from the base portion, which comprises a compressed oil chamber provided on an extending side of a respective hydraulic cylinder and a compressed oil chamber provided on a retracting side thereof; both of said oil chambers being in serial communication with each other; one of said hydraulic cylinders positioned closest to the base portion of said boom being connected to an oil pressure supply and discharge circuit; a plurality of changeover valves controllable by one of an oil pressure and solenoids and each connected to working-pressure supply and exhaust circuits connecting a preceding hydraulic cylinder with a succeeding hydraulic cylinder; control circuits connected to each of said changeover valves controllable by one of oil pressure and solenoids; and a unitary chAngeover valve or switching means connected to each of said control circuits; said unitary changeover valve or switching means being arranged for selectively operating each of said changeover valves to a desired position.
Claim 5
Dependent Claim
53 words
An extension means of a multistage extensible boom as claimed in claim 1, wherein one of said changeover valves controllable by one of oil pressure and solenoids is also connected to said oil pressure supply and discharge circuit connected to one of hydraulic cylinders positioned closest to the base portion of said boom.
Claim 6
Dependent Claim
53 words
An extension means of a multistage extensible boom as claimed in claim 2, wherein one of said changeover valve controllable by one of oil pressure and solenoids is also connected to said oil pressure supply and discharge circuit connected to one of hydraulic cylinders positioned closest to the base portion of said boom.
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) | 1975-01-10 | 1975-07-12 | 1976-01-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-01-10 | 1979-07-12 | 1980-01-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-01-10 | 1983-07-12 | 1984-01-11 | $7700.00 | Window Closed / Lapsed |