Hydraulic work tool with a device for impact damping

Patent metadata

Field	Value
Publication number	US-12539586-B2
Application number	US-202118265175-A
Country	US
Kind code	B2
Filing date	Dec 2, 2021
Priority date	Dec 3, 2020
Publication date	Feb 3, 2026
Grant date	Feb 3, 2026

Abstract

The invention relates to a hydraulic cylinder ( 6 ) with a hydraulically actuatable working piston ( 10 ) movable therein for transferring a working force to an object ( 20 ) to be processed outside of the hydraulic cylinder ( 6 ) accompanied by the buildup of a counterforce, wherein the working piston ( 10 ) has an actuation surface ( 12 ), the actuation surface ( 12 ) borders an actuation space present between the working piston ( 10 ) and the hydraulic cylinder ( 6 ) in a working direction (R) in which the working force is transferred, and for executing an operation, hydraulic fluid can act for moving the working piston ( 10 ) in the working direction (R) toward the actuation surface ( 12 ), accompanied by an enlargement of the actuation space. The invention further relates to a hydraulic work tool ( 1 ) with a hydraulic cylinder ( 6 ), and to a shock absorption method using such a hydraulic cylinder ( 6 ). In order to achieve an effective shock absorption, the invention proposes that an intermediate piston ( 11 ) be arranged before the working piston ( 10 ) in the working direction (R), that the actuation space be divided by the intermediate piston ( 11 ) into an entrance space ( 14 ) and a working space ( 15 ), wherein the entrance space ( 14 ) is formed between a cylinder floor ( 21 ) and the intermediate piston ( 11 ), and the working space ( 15 ) is formed between the working piston ( 10 ) and the intermediate piston ( 11 ), that the hydraulic fluid can flow out of the entrance space ( 14 ) into the working space ( 15 ), accompanied by an enlargement of the working space ( 15 ), and that a mechanical coupling between the working piston ( 10 ) and the intermediate piston ( 11 ) can compensate for an actuation emanating from the hydraulic fluid located in the working space ( 15 ) given a loss in counterforce.

First claim

The invention claimed is:

1 . A set-up comprising:
a hydraulic cylinder; a hydraulically actuatable working piston, the working piston is moveable within the hydraulic cylinder and is configured to transmit a working force to an object to be machined outside the hydraulic cylinder, building up a counterforce, wherein the working piston comprises a pressurization surface which limits a pressurization space existing between the working piston and the hydraulic cylinder in a direction of operation, in which the working force is transmitted; hydraulic fluid provided in the hydraulic cylinder, wherein an ingress of the hydraulic fluid into the pressurization space enlarges the pressurization space and acts on the working piston to move the working piston in the direction of operation to the pressurization surface; and a counterholder, wherein the counterholder is formed by an intermediate piston arranged in front of the working piston in the direction of operation, and the intermediate piston comprises a coupling extension for interaction with a coupling stop of the working piston, or wherein the counterholder is formed by the hydraulic cylinder and the working piston is mechanically coupled to the hydraulic cylinder via a spindle part, and wherein the working piston is configured to be mechanically restrained in the direction of operation before reaching a stop position via a mechanical coupling between the working piston and the counterholder when a drop in the counterforce occurs, thereby preventing additional movement of the working piston in the direction of operation, which can occur without the drop in the counterforce.

2 . The set-up according to claim 1 ,
wherein the pressurization space is divided by the intermediate piston into a preliminary space and a working space, wherein the preliminary space is formed between a cylinder bottom of the hydraulic cylinder and the intermediate piston, and the working space is formed between the working piston and the intermediate piston, wherein the hydraulic fluid is formed to flow from the preliminary space into the working space in order to enlarge the working space, and wherein the mechanical coupling between the working piston and the intermediate piston is formed to compensate for an effect of the hydraulic fluid located in the working space when a drop in the counterforce occurs.

3 . The set-up according to claim 1 , wherein, with the intermediate piston, only the working piston serves to act on the object, in a sense of a transmission of the working force onto the object.

4 . The set-up according to claim 1 , wherein the coupling extension is designed to pass through the pressurization surface.

5 . The set-up according to claim 1 , wherein the coupling stop is formed in the pressurization direction behind the pressurization surface.

6 . The set-up according to claim 1 , wherein the intermediate piston is preloaded in a position distanced away from the working piston.

7 . The set-up according to claim 1 , wherein the intermediate piston comprises a passage opening and furthermore comprises a valve arranged within the passage opening, wherein the valve is moveable between an opening position and a closure position.

8 . The set-up according to claim 7 ,
wherein the pressurization space is divided by the intermediate piston into a preliminary space and a working space, wherein the preliminary space is formed between a cylinder bottom of the hydraulic cylinder and the intermediate piston, and the working space is formed between the working piston and the intermediate piston, wherein the hydraulic fluid is formed to flow from the preliminary space into the working space in order to enlarge the working space, wherein the mechanical coupling between the working piston and the intermediate piston is formed to compensate for an effect of the hydraulic fluid located in the working space when a drop in counterforce occurs, and wherein the valve is configured to allow the hydraulic fluid to flow from the preliminary space into the working space.

9 . The set-up according to claim 7 , wherein the valve is configured to allow a reduced flow rate of the hydraulic fluid in the closed position in comparison to the opening position.

10 . The set-up according to claim 7 , wherein the valve is configured to be guided into the opening position by a stop.

11 . The set-up according to claim 7 , wherein the valve is preloaded to its closure position.

12 . The set-up according to claim 1 , wherein the intermediate piston leaves a gap opening to an inner surface of the hydraulic cylinder.

13 . The set-up according to claim 1 , wherein the pressurization space is divided by the intermediate piston into a preliminary space and a working space, and wherein the intermediate piston is configured to be applied independently of the working force, with a retaining force which has a supporting effect with regard to a flow of the hydraulic fluid into the working space via the intermediate piston in order to enlarge the working space.

14 . The set-up according to claim 13 , wherein the restraint retaining force allows the intermediate piston to move in the direction of operation.

15 . The set-up according to claim 1 , wherein the spindle part is rotatable.

16 . The set-up according to claim 1 , wherein the spindle part is fixed into position.

17 . The set-up according to claim 1 , wherein the spindle part is fixed in the intermediate piston.

18 . The set-up according to claim 1 , wherein the spindle part is fixed in the hydraulic cylinder.

19 . A combination of the set-up according to claim 1 and a hydraulic tool comprising a working head.

20 . The set-up and the hydraulic tool according to claim 19 , wherein the hydraulic tool is a cutting tool.

21 . A set-up comprising:
a hydraulic cylinder; a hydraulically actuatable working piston comprising a coupling stop, the working piston being moveable within the hydraulic cylinder and is configured to transmit a working force to an object to be machined outside the hydraulic cylinder, building up a counterforce, the working piston comprising a pressurization surface, which limits a pressurization space existing between the working piston and the hydraulic cylinder in a direction of operation, in which the working force is transmitted; hydraulic fluid provided in the hydraulic cylinder, wherein an ingress of the hydraulic fluid into the pressurization space enlarges the pressurization space and acts on the working piston to move the working piston in the direction of operation to the pressurization surface, a counterholder comprising an intermediate piston or being formed by the hydraulic cylinder, and a coupling extension is formed on the counterholder; and wherein the working piston is configured to be mechanically restrained before reaching a stop position in the direction of operation by a mechanical coupling between the working piston and the counterholder when a drop in the counterforce occurs, thereby preventing additional movement of the working piston in the direction of operation, which can occur without a drop in the counterforce.

22 . Method for absorbing shock of a hydraulically actuatable working piston that is moveable within a hydraulic cylinder, for transmitting a working force to an object to be machined outside the hydraulic cylinder, building up a counterforce, wherein the working piston comprises a pressurization surface, the pressurization sur

Assignees

• Klauke Gmbh Gustav

Inventors

• Frenken Egbert

Classifications

• B25F5/005

  Hydraulic driving means · CPC title

• B25B27/10 Primary

  inserting fittings into hoses · CPC title

• B23D29/002

  for cutting wire or the like · CPC title

• B25B27/146

  Clip clamping hand tools · CPC title