US3913448A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hydraulic actuator
Assignee: Loughborough University
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Filing: 1972-07-31
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Granted: 1975-10-21
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Expires: 1992-07-31
Abstract
Abstract A hydraulic actuator comprises a cylinder containing a doubleacting piston, a port adjacent each end of the cylinder and a piston-controlled intermediate port opened by the piston in moving to an intermediate position, each of the ports being connected to progressively adjustable valve means (for example a continuously rotatable valve means) coupled to operate in timed relationship to one another. The hydraulic actuator may also include a second cylinder containing a second piston which carries a probe extending axially into the first cylinder to abut the first-mentioned piston and having a port connected to continuously rotatable valve means arranged to operate in timed relationship to the first-mentioned valve means. There is also described a knitting machine including a plurality of needles, a separate hydraulic actuator for each needle of the machine, and on-off valve means for controlling supply of hydraulic fluid under pressure to the hydraulic actuators to operate hydraulic actuators in sequence to effect a knitting operation. The said valve means may be arranged to operate actuators of needles at spaced location simultaneously and the actuators of each of a number of groups of actuators sequentially. Each of the hydraulic actuators may be of the kind described above.
Inventors
- 👤 Terence Patrick Priestley
- 👤 John Duncan Garside
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 23:16
CPC Classifications
F; F16; F16H; F16H43/00; D; D04; D04B; D04B15/00; D04B15/94; F15; F15B; F15B11/00; F15B11/02; F15B13/00; F15B13/02; F15B13/06; F15B21/00; F15B21/02; F15B2211/00; F15B2211/30; F15B2211/305; F15B2211/30505; F15B2211/30525; F15B2211/3056; F15B2211/30585; F15B2211/32; F15B2211/321; F15B2211/70; F15B2211/705; F15B2211/7051; F15B2211/7055
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
212 words
A hydraulic actuator comprising a first cylinder containing a first double-acting piston, first and second ports each adjacent a different end of said first cylinder and piston-controlled port means intermediate the ends of said first cylinder opened and closed by said first piston in moving between the ends of said first cylinder, said first and second ports being connected to first and second sequential valve portion controlled ports in a housing independent of the actuator and respectively controlling connection of said first and second ports in a predetermined sequence to a source of pressurized hydraulic medium and to exhaust, said piston-controlled port means including a first piston-controlled port connected to a third sequential valve portion controlled port in said housing, a second cylinder aligned end-to-end with said first cylinder and containing a second piston, a probe slidable relative to the cylinders and extending from the first cylinder to the second cylinder to prevent the two pistons moving closer to one another than a predetermined minimum, said second cylinder having a third port connected to a fourth sequential valve portion controlled port, and coupling means in said housing connecting said first, second, third and fourth valve portions to insure operation of each valve portion in timed relationship with the other three valve portions.
Claim 2
Dependent Claim
212 words
A hydraulic actuator comprising a first cylinder containing a first double-acting piston, first and second ports each adjacent a different end of said first cylinder and piston-controlled port means intermediate the ends of said first cylinder opened and closed by said first piston in moving between the ends of said first cylinder, said first and second ports being connected to first and second sequential valve portion controlled ports in a housing independent of the actuator and respectively controlling connection of said first and second ports in a predetermined sequence to a source of pressurized hydraulic medium and to exhaust, said piston-controlled port means including a first piston-controlled port connected to a third sequential valve portion controlled port in said housing, a second cylinder aligned end-to-end with said first cylinder and containing a second piston, a probe slidable relative to the cylinders and extending from the first cylinder to the second cylinder to prevent the two pistons moving closer to one another than a predetermined minimum, said second cylinder having a third port connected to a fourth sequential valve portion controlled port, and coupling means in said housing connecting said first, second, third and fourth valve portions to insure operation of each valve portion in timed relationship with the other three valve portions.
Claim 3
Dependent Claim
50 words
A hydraulic actuator as claimed in claim 1, in which the third port of said second cylinder is adjacent one end of the latter, said second cylinder also having a second piston-controlled port means opened and closed by said second piston in moving between the ends of said second cylinder.
Claim 4
Dependent Claim
55 words
A hydraulic actuator as claimed in claim 2, including an actuating member connected to said first piston for movement between two end positions, and wherein said second piston is operable through the intermediary of said probe for moving said first piston to position the actuating member in a third position intermediate said two end positions.
Claim 5
Dependent Claim
60 words
A hydraulic actuator as claimed in claim 3, in which said piston-controlled port means of said first cylinder further includes a third piston-controlled port which, when opened by said first piston, connects one of said first and second ports to exhaust when said first piston is in a position corresponding to one of said end positions of the actuating member.
Claim 6
Dependent Claim
47 words
A hydraulic actuator as claimed in claim 4, in which said first piston-controlled port of said first cylinder, when opened by said first piston, connects said second port to exhaust when said first piston is in a position corresponding to said third position of the actuating member.
Claim 7
Dependent Claim
18 words
A hydraulic actuator as claimed in claim 1, including means for continuously rotating the four sequential valve portions.
Claim 8
Dependent Claim
33 words
A hydraulic actuator as claimed in claim 1, in which said four sequential valve portions are assembled in a unit which is mounted in a common casing and means for rotating said unit.
Claim 9
Dependent Claim
34 words
A hydraulic actuator as claimed in claim 1, in which said probe is carried by one of the pistons and extends axially into the cylinder of the other piston to abut the other piston.
Claim 10
Dependent Claim
44 words
A hydraulic actuating system comprising a plurality of hydraulic actuators as claimed in claim 1, in which said coupling means is common to the sequential valve portions of all the actuators, whereby all the valve portions are operated in timed relationship with one another.
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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) | 1978-10-20 | 1979-04-21 | 1979-10-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-10-20 | 1983-04-21 | 1983-10-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-10-20 | 1987-04-21 | 1987-10-21 | $7700.00 | Window Closed / Lapsed |