WO2004020155A1 - Accumulator with foam plastic for a liquid driven hammer device - Google Patents

Accumulator with foam plastic for a liquid driven hammer device Download PDF

Info

Publication number
WO2004020155A1
WO2004020155A1 PCT/SE2003/001313 SE0301313W WO2004020155A1 WO 2004020155 A1 WO2004020155 A1 WO 2004020155A1 SE 0301313 W SE0301313 W SE 0301313W WO 2004020155 A1 WO2004020155 A1 WO 2004020155A1
Authority
WO
WIPO (PCT)
Prior art keywords
accumulator
liquid
hammer device
driven hammer
liquid driven
Prior art date
Application number
PCT/SE2003/001313
Other languages
French (fr)
Inventor
Lennart Donsé
Original Assignee
Atlas Copco Rock Drills Ab
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Atlas Copco Rock Drills Ab filed Critical Atlas Copco Rock Drills Ab
Priority to AU2003253548A priority Critical patent/AU2003253548A1/en
Publication of WO2004020155A1 publication Critical patent/WO2004020155A1/en

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
    • B25D—PERCUSSIVE TOOLS
    • B25D9/00—Portable percussive tools with fluid-pressure drive, i.e. driven directly by fluids, e.g. having several percussive tool bits operated simultaneously
    • B25D9/14—Control devices for the reciprocating piston
    • B25D9/145—Control devices for the reciprocating piston for hydraulically actuated hammers having an accumulator
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
    • B25B—TOOLS OR BENCH DEVICES NOT OTHERWISE PROVIDED FOR, FOR FASTENING, CONNECTING, DISENGAGING OR HOLDING
    • B25B21/00—Portable power-driven screw or nut setting or loosening tools; Attachments for drilling apparatus serving the same purpose
    • B25B21/02—Portable power-driven screw or nut setting or loosening tools; Attachments for drilling apparatus serving the same purpose with means for imparting impact to screwdriver blade or nut socket

Definitions

  • the present invention relates to an accumulator for a liquid driven hammer device.
  • EP 885693 it is previously known to replace the accumulator gas with a body of foamed plastics to bias the membrane.
  • the membrane is kept because the foamed plastics is exerted to destructive influence when in contact with hydraulic fluid, EP 885693, col. 1, lines 47-50.
  • the present invention aims at avoiding the above mentioned drawbacks.
  • This is achieved by replacing the normal gas accumulator with a body of foamed plastic, preferably microcellular polyurethane, provided with a sealing surface layer, preferably in form of a lining of polyurethane, to separate the liquid with varying pressure from the inside of the body.
  • a sealing surface layer preferably in form of a lining of polyurethane
  • the invention thus makes it possible to place the accumulator closer to the place where pressure variations are created.
  • the accumulator shown in the drawing is intended to be mounted in a hydraulic conduit where one has a varying pressure.
  • the idea according to the invention is however not limited to conduit accumulators but can equally well be directly connected to a machine which has channels with varying pressure to smooth large pressure variations and reduce the risk for cavitation. It is also possible to place the accumulator inside the machine close to the source of pressure vaiations.
  • the accumulator shown in the drawing comprises a housing 1.
  • Housing 1 comprises a central part 6 and a cylindrical part 7 about it. Between parts 6,7 there is a room 2 in which a body 4 of foamed plastics is arranged. Body 4 is provided with a surface layer 5.
  • the central part 6 surrounds a channel 3 in which a liquid with varying pressure is situated.
  • the central part 6 comprises a number of radial openings 8 which connect channel 3 with room 2.
  • Cylinder part 7 is kept in place by an end piece 9 and a nut 11.
  • hydraulic conduits are pressed against conical surfaces 12 and 13.
  • the foamed plastics body is advantageously made of microcellular polyurethane, and the surface layer 5 which separates the inside of body 4 from the liquid with varying pressure is advantageously made of a sealing lining of polyurethane.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Pipe Accessories (AREA)
  • Supply Devices, Intensifiers, Converters, And Telemotors (AREA)
  • Percussive Tools And Related Accessories (AREA)

Abstract

Accumulator for liquid driven hammer device comprising a housing (1), a room (2) arranged in the housing in connection with a channel (3) in which a liquid with varying pressure is situated in which the room (2) comprises a body (4) of foamed plastics provided with a surface layer (5) which separates the liquid from the inside of the body (4). The foamed plastics is microcellular polyurethane and the surface layer (5) is a sealing lining of polyurethane.

Description

ACCUMULATOR WITH FOAM PLASTIC FOR A LIQUID DRIVEN HAMMER DEVICE .
The present invention relates to an accumulator for a liquid driven hammer device.
In liquid driven hammer devices one uses accumulators to smooth pressure variations in the hydraulic system and see to it that the hammer device momentarily is provided with a sufficient amount of hydraulic liquid during its working stroke. In previously known accumulators, see for instance US 4264107, gas volumes under pressure are used to take care of the momentary flows caused by the pressure pulsations. The liquid can hereby be separated from the gas volume either by a membrane or by a piston. Both these alternatives are shown in US 4264107. Both these accumulators have the drawback that they have to be supplied with pressure gas, usually nitrogen, at intervals since there is a certain leakage. It has turned out that the gas leakage through a rubber membrane at lower pressures becomes larger through the pores in the rubber membrane than at higher pressures which results therein that a low pressure accumulator loses its accumulator capacity after a relatively short time. If, furthermore, the pressure is relatively high there is the additional drawback that the accumulator must be made and tested according to actual pressure vessel norms. This is both time-consuming and requires special equipment.
According to another impact device, see EP 885693, it is previously known to replace the accumulator gas with a body of foamed plastics to bias the membrane. The membrane is kept because the foamed plastics is exerted to destructive influence when in contact with hydraulic fluid, EP 885693, col. 1, lines 47-50.
The present invention, which is defined in the subsequent claims, aims at avoiding the above mentioned drawbacks. This is achieved by replacing the normal gas accumulator with a body of foamed plastic, preferably microcellular polyurethane, provided with a sealing surface layer, preferably in form of a lining of polyurethane, to separate the liquid with varying pressure from the inside of the body. In this way it is possible to dispense with the accumulator membrane. The invention thus makes it possible to place the accumulator closer to the place where pressure variations are created. An embodiment of the invention is described below with reference to the acompanying drawing which shows a section through an accumulator according to the invention.
The accumulator shown in the drawing is intended to be mounted in a hydraulic conduit where one has a varying pressure. The idea according to the invention is however not limited to conduit accumulators but can equally well be directly connected to a machine which has channels with varying pressure to smooth large pressure variations and reduce the risk for cavitation. It is also possible to place the accumulator inside the machine close to the source of pressure vaiations. The accumulator shown in the drawing comprises a housing 1. Housing 1 comprises a central part 6 and a cylindrical part 7 about it. Between parts 6,7 there is a room 2 in which a body 4 of foamed plastics is arranged. Body 4 is provided with a surface layer 5. The central part 6 surrounds a channel 3 in which a liquid with varying pressure is situated. The central part 6 comprises a number of radial openings 8 which connect channel 3 with room 2. Cylinder part 7 is kept in place by an end piece 9 and a nut 11. In use hydraulic conduits are pressed against conical surfaces 12 and 13. The foamed plastics body is advantageously made of microcellular polyurethane, and the surface layer 5 which separates the inside of body 4 from the liquid with varying pressure is advantageously made of a sealing lining of polyurethane.

Claims

Claims:
1. Accumulator for liquid driven hammer device comprising a housing (1), a room (2) arranged in the housing in connection with a channel (3) in which a liquid with varying pressure is situated, characterized in that the room (2) comprises a body (4) of foamed plastics provided with a surface layer (5) which separates the liquid from the inside of the body (4).
2. Accumulator according to claim 1, characterized in that the foamed plastics is microcellular polyurethane and that the surface layer (5) is a sealing lining of polyurethane.
PCT/SE2003/001313 2002-08-29 2003-08-26 Accumulator with foam plastic for a liquid driven hammer device WO2004020155A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU2003253548A AU2003253548A1 (en) 2002-08-29 2003-08-26 Accumulator with foam plastic for a liquid driven hammer device

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE0202545A SE525600C2 (en) 2002-08-29 2002-08-29 Accumulator for liquid-powered percussion with a body of foamed plastic
SE0202545-0 2002-08-29

Publications (1)

Publication Number Publication Date
WO2004020155A1 true WO2004020155A1 (en) 2004-03-11

Family

ID=20288823

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/SE2003/001313 WO2004020155A1 (en) 2002-08-29 2003-08-26 Accumulator with foam plastic for a liquid driven hammer device

Country Status (3)

Country Link
AU (1) AU2003253548A1 (en)
SE (1) SE525600C2 (en)
WO (1) WO2004020155A1 (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2010077199A1 (en) * 2008-12-29 2010-07-08 Atlas Copco Rock Drills Ab Accumulator membrane unit, method for the production thereof and rock drilling machine including such an accumulator membrane unit
US9151386B2 (en) 2013-03-15 2015-10-06 Caterpillar Inc. Accumulator membrane for a hydraulic hammer
US9555531B2 (en) 2013-03-15 2017-01-31 Caterpillar Inc. Hydraulic hammer having co-axial accumulator and piston
US9592598B2 (en) 2013-03-15 2017-03-14 Caterpillar Inc. Hydraulic hammer having impact system subassembly

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2231292A (en) * 1989-05-04 1990-11-14 Desoutter Ltd Hydraulic impulse torque generator
US5653263A (en) * 1990-11-10 1997-08-05 Robert Bosch Gmbh Bubble storing device with bubble having different zones
SE509915C2 (en) * 1997-06-09 1999-03-22 Atlas Copco Tools Ab Hydraulic torque pulse generator

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2231292A (en) * 1989-05-04 1990-11-14 Desoutter Ltd Hydraulic impulse torque generator
US5653263A (en) * 1990-11-10 1997-08-05 Robert Bosch Gmbh Bubble storing device with bubble having different zones
SE509915C2 (en) * 1997-06-09 1999-03-22 Atlas Copco Tools Ab Hydraulic torque pulse generator

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2010077199A1 (en) * 2008-12-29 2010-07-08 Atlas Copco Rock Drills Ab Accumulator membrane unit, method for the production thereof and rock drilling machine including such an accumulator membrane unit
US8291937B2 (en) 2008-12-29 2012-10-23 Atlas Copco Rock Drills Ab Accumulator membrane unit, method for production thereof and rock drilling machine including such an accumulator membrane unit
US9151386B2 (en) 2013-03-15 2015-10-06 Caterpillar Inc. Accumulator membrane for a hydraulic hammer
US9555531B2 (en) 2013-03-15 2017-01-31 Caterpillar Inc. Hydraulic hammer having co-axial accumulator and piston
US9592598B2 (en) 2013-03-15 2017-03-14 Caterpillar Inc. Hydraulic hammer having impact system subassembly
US9822802B2 (en) 2013-03-15 2017-11-21 Caterpillar Inc. Accumulator membrane for a hydraulic hammer
US10562166B2 (en) 2013-03-15 2020-02-18 Caterpillar Inc. Hydraulic hammer having co-axial accumulator and piston

Also Published As

Publication number Publication date
AU2003253548A1 (en) 2004-03-19
SE0202545D0 (en) 2002-08-29
SE0202545L (en) 2004-03-01
SE525600C2 (en) 2005-03-15

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