Hydraulic drive

Patent metadata

Field	Value
Publication number	US-10800124-B2
Application number	US-201715724771-A
Country	US
Kind code	B2
Filing date	Oct 4, 2017
Priority date	Oct 4, 2016
Publication date	Oct 13, 2020
Grant date	Oct 13, 2020

Abstract

In a hydraulic drive of a tool piston in a cylinder first and second flat contact areas each are contiguous, when moving into and in the open position of the valve member between the detent element and the valve member, wherein a pressure-limiting valve that can be loaded with the pressure in the cylinder from a closed position to an open position and a detent element loaded by a spring in the locking direction to positively hold a neck of a valve member of the pressure-limiting valve are arranged in the open position, wherein the detent element at least via the tool piston at its return to a released position can be moved and, when moving the valve member to the open position of the pressure-limiting valve, non-positively acts on the valve member.

First claim

What is claimed is:

1. A hydraulic drive of a tool piston in a cylinder that can be loaded against a return spring by a pump, the hydraulic drive comprising a pressure-limiting valve that can be loaded with pressure in the cylinder from a closed position to an open position against spring force, and a detent element, wherein the detent element is loadable by a spring to a locked position, to hold a valve member of the pressure-limiting valve lifted from a seat in the open position, wherein the detent element is arranged transversely to the valve member and can be moved from the locked position to a released position at least via the tool piston at its return stroke, wherein, in the locked position, the detent element is configured to support the valve member, and when the valve member is moving to the open position of the pressure-limiting valve, the detent element is configured to act on the valve member laterally, wherein when moving the valve member into its open position, or when the valve member is in its open position, contact areas of the detent element and the valve member are contiguous, and wherein the detent element comprises a longitudinally drilled cylindrical detent sleeve that is penetrated by the valve member in a transverse passage, and a through-hole of the detent sleeve forms a part of a pressure line and a part of a return line.

2. The hydraulic drive according to claim 1 , wherein the contact areas comprise a flat contact area on each of the detent element and the valve member, and the flat contact areas are contiguous in the open position of the pressure-limiting valve and in the locked position of the detent element.

3. The hydraulic drive according to claim 1 , wherein the contact areas comprise a partially cylindrical contact area on each of the detent element and the valve member, and the partially cylindrical contact areas are contiguous when the valve member is being moved to the open position of the pressure-limiting valve.

4. The hydraulic drive according to claim 1 , wherein axes of a pump port, a housing hole for the detent element and a hole for the valve member intersect at right angles in one point, wherein the housing hole and the hole are arranged in a valve insert having the seat.

5. The hydraulic drive according to claim 4 , wherein the valve insert is built into a hydraulic drive block containing the pump port and being connectable to the cylinder via a single hydraulic interface, and a bypass of the valve insert extends from the pump port to the through-hole.

6. The hydraulic drive according to claim 1 , wherein the valve member has a guided neck of small diameter, a shank carrying a sealing surface and therebetween a collar having a diameter that is at least larger than that of the neck and having a cylindrical outer circumference, and can be displaced with the collar in the transverse passage of the detent sleeve.

7. The hydraulic drive according to claim 2 , wherein the flat contact area on the detent sleeve is restricted by the transverse passage, a bottom of a flattening in a cylinder jacket of the detent sleeve and a recess in the flattening.

8. The hydraulic drive according to claim 6 , wherein the transverse passage is a cross hole of a diameter that corresponds at least to the diameter of the collar, and an arc curvature of a cross hole side having a wall thickness of the detent sleeve corresponds to a cylinder curvature of the outer circumference of the collar and forms a contact area of the detent sleeve.

9. The hydraulic drive according to claim 2 , wherein axes of a pump port, a housing hole for the detent sleeve and a hole for the valve member intersect at right angles in one point, wherein the housing hole and the hole are arranged in a valve insert having the seat.

10. The hydraulic drive according to claim 9 , wherein the detent sleeve is guided without a seal with a slide fitting in the housing hole.

11. The hydraulic drive according to claim 4 , wherein the valve member has a guided neck of small diameter, a shank carrying a sealing surface and therebetween a collar having a diameter that is at least larger than that of the neck and having a cylindrical outer circumference, and can be displaced with the collar in the transverse passage of the detent sleeve.

12. The hydraulic drive according to claim 11 , wherein in the valve insert between the shank of the valve member and the hole for the valve member a space forms a further part of the return line up to the seat.

13. The hydraulic drive according to claim 11 , wherein of the seat in the valve insert is larger than the diameter of the neck of the valve member guided in the hole.

14. The hydraulic drive according to claim 5 , wherein the spring loading the detent element is assigned to an end of the detent element that protrudes into the cylinder or another end facing away from the cylinder and is supported in the block.

15. The hydraulic drive according to claim 1 , wherein the detent sleeve has inlets to the through-hole that are distributed in a circumferential direction and offset to each other toward an axis of the detent sleeve.

16. The hydraulic drive according to claim 1 , wherein height of the hydraulic drive seen in a longitudinal direction of the cylinder is smaller than a diameter of the tool piston.

17. A hydraulic drive for a tool piston in a cylinder that can be loaded against a return spring by a pump, the hydraulic drive comprising:
a pressure-limiting valve that can be loaded with pressure in the cylinder from a closed position to an open position against spring force; and
a detent element that is loadable by a spring to a locked position, to hold a valve member of the pressure-limiting valve lifted from a seat in the open position, wherein the detent element is arranged transversely to the valve member and can be moved from the locked position to a released position at least via the tool piston at its return stroke, wherein, in the locked position, the detent element is configured to support the valve member, and when the valve member is being moved to the open position of the pressure-limiting valve, the detent element is configured to act on the valve member laterally, wherein when the valve member is in the open position of the pressure-limiting valve, flat contact areas of the detent element and the valve member are contiguous, and wherein the detent element comprises a cylindrical detent sleeve that is penetrated by the valve member in a transverse passage, and a through-hole of the detent sleeve forms a part of a pressure line and a part of a return line.

18. A tool comprising the hydraulic drive of claim 17 .

19. A hydraulic drive for a tool piston in a cylinder that can be loaded against a return spring by a pump, the hydraulic drive comprising:
a pressure-limiting valve that can be loaded with pressure in the cylinder from a closed position to an open position against spring force; and
a detent element that is loadable by a spring to a locked position, to hold a valve member of the pressure-limiting valve lifted from a seat in the open position, wherein the detent element is arranged transversely to the valve member and can be moved from the locked position to a released position at least via the tool piston at its return stroke, wherein, in the locked position, the detent element is configured to support the valve member, and when the valve member is being moved to the open position of the pressure-limiting valve, the detent element is configured to act on the valve member laterally, wherein when the valve member is in i

Assignees

• Hawe Hydraulik Se

Inventors

• Haehl Alexander

Classifications

• B30B15/22 Primary

  controlling the degree of pressure applied by the ram during the pressing stroke · CPC title

• F15B15/204

  Control means for piston speed or actuating force without external control, e.g. control valve inside the piston (F15B11/02, F15B15/22 take precedence) · CPC title

• F15B11/08

  with only one servomotor · CPC title

• F15B13/01

  Locking-valves or other detent {i.e. load-holding} devices · CPC title

• F15B15/225

  with valve stems operated by contact with the piston end face or with the cylinder wall · CPC title