US3824896A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hydraulic compression circuits
Assignee: Hoerner Waldorf Corp
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Filing: 1971-11-24
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Granted: 1974-07-23
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Expires: 1991-11-24
Abstract
Abstract The cycle of operation of a compression platen or the like reciprocated by a main cylinder by adding one or more additional cylinders having piston rods engaging the platen. Fluid pressure is directed against the pistons in the main cylinder and additional cylinders in a direction to move the platen in a compression direction. The other ends of the additional cylinders are connected to the fluid pressure supply line through a check valve to circulate the fluid being forced from the additional cylinders back to the cylinders without flowing through the reservoir pump, moving the platen at relatively high speed and relatively low force. When resistance to movement of the platen exceeds a predetermined amount, the circulating line is closed and fluid from the additional cylinders is bypassed to the reservoir.
Inventors
- 👤 H Tull
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 03:04
CPC Classifications
B; B28; B28B; B28B11/00; B28B11/14; F; F15; F15B; F15B11/00; F15B11/16; F15B2211/00; F15B2211/30; F15B2211/32; F15B2211/327; F15B2211/40; F15B2211/405; F15B2211/40576; F15B2211/40584; F15B2211/41; F15B2211/411; F15B2211/415; F15B2211/41509; F15B2211/41527; F15B2211/42; F15B2211/426; F15B2211/428; F15B2211/46; F15B2211/47; F15B2211/473; F15B2211/50; F15B2211/505; F15B2211/50509; F15B2211/50518; F15B2211/515; F15B2211/5159; F15B2211/55; F15B2211/60; F15B2211/63; F15B2211/6303; F15B2211/6306; F15B2211/6313; F15B2211/6336; F15B2211/70; F15B2211/71; F15B2211/7107; F15B2211/7114; F15B2211/7128; F15B2211/75
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
373 words
A hydraulic circuit for use in combination with a movable platen which is subject to increasing resistance to movement during its movement in one direction, a main cylinder, piston rod and piston connected to said platen for reciprocating the same, the end of the cylinder through which the piston rod extends comprising the rod end and the other end comprising the head end, a fluid pump and a fluid reservoir, including: at least one additional cylinder, piston rod and piston engaging said platen for urging said platen in said one direction, the end of the cylinder through which the piston rod extends comprising the rod end and the other end comprising the head end. a reversing valve, a conduit from said pump to said reversing valve, a conduit from said reversing valve to said reservoir, a first passage from said reversing valve to the head ends of both said cylinders, a second passage from said reversing valve to the piston rod end of said main cylinder, whereby said reversing valve may direct fluid from said pump to either of said passages while connecting the other passage to said reservoir, a first connection from the piston rod end of said additional cylinder to said first passage, said connection including a check valve through which fluid may flow from said additional cylinder to said first passage to combine with fluid therein, but said check valve preventing a reverse flow, a second connection from said first connection to said reservoir and including a normally closed bypass valve, and means operable by movement of said movable platen to a point near the end of its compression stroke to open said bypass valve to direct fluid from said piston rod end of said additional cylinder to said reservoir, closing said check valve, a pilot valve connected in parallel relation with said check valve and operable, when open, to permit a reverse flow from said first passage to the piston rod end said additional cylinder, said pilot valve being opened by fluid pressure from said pump in said second passage, whereby when said reversing valve directs fluid under pressure to said second passage, fluid may flow from said first passage to the piston rod end of said additional cylinder.
Claim 2
Dependent Claim
373 words
A hydraulic circuit for use in combination with a movable platen which is subject to increasing resistance to movement during its movement in one direction, a main cylinder, piston rod and piston connected to said platen for reciprocating the same, the end of the cylinder through which the piston rod extends comprising the rod end and the other end comprising the head end, a fluid pump and a fluid reservoir, including: at least one additional cylinder, piston rod and piston engaging said platen for urging said platen in said one direction, the end of the cylinder through which the piston rod extends comprising the rod end and the other end comprising the head end. a reversing valve, a conduit from said pump to said reversing valve, a conduit from said reversing valve to said reservoir, a first passage from said reversing valve to the head ends of both said cylinders, a second passage from said reversing valve to the piston rod end of said main cylinder, whereby said reversing valve may direct fluid from said pump to either of said passages while connecting the other passage to said reservoir, a first connection from the piston rod end of said additional cylinder to said first passage, said connection including a check valve through which fluid may flow from said additional cylinder to said first passage to combine with fluid therein, but said check valve preventing a reverse flow, a second connection from said first connection to said reservoir and including a normally closed bypass valve, and means operable by movement of said movable platen to a point near the end of its compression stroke to open said bypass valve to direct fluid from said piston rod end of said additional cylinder to said reservoir, closing said check valve, a pilot valve connected in parallel relation with said check valve and operable, when open, to permit a reverse flow from said first passage to the piston rod end said additional cylinder, said pilot valve being opened by fluid pressure from said pump in said second passage, whereby when said reversing valve directs fluid under pressure to said second passage, fluid may flow from said first passage to the piston rod end of said additional cylinder.
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) | 1977-07-22 | 1978-01-21 | 1978-07-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-07-22 | 1982-01-21 | 1982-07-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-07-22 | 1986-01-21 | 1986-07-23 | $7700.00 | Window Closed / Lapsed |