초록 ▼

A hydraulic tool including a frame; a ram movably connected to the frame; and a hydraulic drive system on the frame for moving the ram on the frame by hydraulic pressure. The hydraulic drive system includes an automatic release system for automatically releasing hydraulic fluid from the hydraulic dr

A hydraulic tool including a frame; a ram movably connected to the frame; and a hydraulic drive system on the frame for moving the ram on the frame by hydraulic pressure. The hydraulic drive system includes an automatic release system for automatically releasing hydraulic fluid from the hydraulic drive system. The automatic release system comprises a first valve which is adapted to be automatically opened by a predetermined hydraulic pressure and a second valve which is adapted to be opened by hydraulic fluid passing through the first valve.

대표청구항 ▼

What is claimed is: 1. A hydraulic tool comprising: a frame; a ram movably connected to the frame; and a hydraulic drive system on the frame for moving the ram on the frame by hydraulic pressure, wherein the hydraulic drive system comprises an automatic release system for automatically releasing hy

What is claimed is: 1. A hydraulic tool comprising: a frame; a ram movably connected to the frame; and a hydraulic drive system on the frame for moving the ram on the frame by hydraulic pressure, wherein the hydraulic drive system comprises an automatic release system for automatically releasing hydraulic fluid from the hydraulic drive system, wherein the automatic release system comprises a first valve which is adapted to be automatically opened by a predetermined hydraulic pressure and a second valve which is adapted to be opened by hydraulic fluid passing through the first valve, wherein the second valve comprises a second valve seat on the frame, a ball adapted to sit on the valve seat and a pilot spool at the valve seat and adapted to move the ball off of the valve seat. 2. A hydraulic tool as in claim 1 wherein the pilot spool comprises a conduit therethrough. 3. A hydraulic tool as in claim 2 wherein the pilot spool comprises a rear end and a relatively smaller front end. 4. A hydraulic tool as in claim 1 further comprising a bumper biased by a spring against the ball. 5. A hydraulic tool as in claim 4 wherein a portion of the bumper projects into a ram cylinder of the frame which houses the ram. 6. A hydraulic tool as in claim 1 wherein the first valve comprises a first valve seat on the frame and a valve needle having a general cone shaped end located in the first valve seat and biased by a spring against the first valve seat. 7. A hydraulic tool as in claim 1 further comprising a manual release system for manually releasing hydraulic fluid from the hydraulic drive system. 8. A hydraulic tool as in claim 7 wherein the manual release system comprises a member adapted to be manually moved by a user to manually move a portion of the second valve. 9. A hydraulic tool as in claim 7 wherein the manual release system comprises a member adapted to be manually moved by a user to manually move a portion of the first valve. 10. A hydraulic tool as in claim 7 wherein the manual release system is substantially separate from the first and second valves. 11. A hydraulic tool comprising: a frame; a ram movably connected to the frame; and a hydraulic drive system on the frame for moving the ram on the frame by hydraulic pressure, wherein the hydraulic drive system comprises an automatic release system for automatically releasing hydraulic fluid from the hydraulic drive system, wherein the automatic release system comprises a first valve and a second valve, wherein the second valve is adapted to be closed by physical contact of the ram against a bumper portion of the second valve. 12. A hydraulic tool as in claim 11 wherein the second valve comprises a second valve seat on the frame, a ball adapted to sit on the valve seat and a pilot spool at the valve seat and adapted to move the ball off of the valve seat. 13. A hydraulic tool as in claim 12 wherein the pilot spool comprises a conduit therethrough. 14. A hydraulic tool as in claim 13 wherein the pilot spool comprises a rear end and a relatively smaller front end. 15. A hydraulic tool as in claim 12 wherein the bumper portion biased by a spring against the ball. 16. A hydraulic tool as in claim 15 wherein the bumper portion projects into a rain cylinder of the frame which houses the ram. 17. A hydraulic tool as in claim 12 wherein the first valve comprises a first valve seat on the frame and a. valve needle having a general cone shaped end located in the first valve seat and biased by a spring against the first valve seat. 18. A hydraulic tool as in claim 11 further comprising a manual release system for manually releasing hydraulic fluid from the hydraulic drive system. 19. A hydraulic tool as in claim 18 wherein the manual release system comprises a member adapted to be manually moved by a user to manually move a portion of the second valve. 20. A hydraulic tool as in claim 18 wherein the manual release system comprises a member adapted to be manually moved by a user to manually move a portion of the first valve. 21. A hydraulic tool as in claim 18 wherein the manual release system is substantially separate from the first and second valves. 22. A hydraulic tool comprising: a frame; a ram movably connected to the frame; and a hydraulic drive system on the frame for moving the ram on the frame by hydraulic pressure, wherein the hydraulic drive system comprises an automatic release system for automatically releasing hydraulic fluid from the hydraulic drive system and a manual release system for manually releasing hydraulic fluid from the hydraulic drive system, wherein the automatic release system comprises a first valve and a second valve, and wherein the manual release system is adapted to allow a user to manually move a portion of the first valve or the second valve. 23. A hydraulic tool as in claim 22 wherein the second valve comprises a second valve seat on the frame, a ball adapted to sit on the valve seat and a pilot spool at the valve seat and adapted to move the ball off of the valve seat, and wherein the pilot spool comprises a conduit therethrough, and wherein the first valve is adapted to be automatically opened by a predetermined hydraulic pressure and the second valve is adapted to be opened by hydraulic fluid passing through the first valve. 24. A hydraulic tool comprising: a frame; a ram movably connected to the frame; and a hydraulic drive system on the frame for moving the ram on the frame by hydraulic pressure, wherein the hydraulic drive system comprises an automatic release system for automatically releasing hydraulic fluid from the hydraulic drive system, wherein the automatic release system comprises a first valve which is adapted to be automatically opened by a predetermined hydraulic pressure and a second valve which is adapted to be opened by hydraulic fluid passing through the first valve, wherein the automatic release system is configured to close the first valve while the second valve remains open. 25. A hydraulic tool as in claim 24 wherein the automatic release system is configured to close the first valve before the ram reaches its rearward position.