Hydraulic breaking hammer with lubricated implement guide sleeve

(54) Designation; Hydraulic breaker with lubricated tool sleeve (56) Published publications: SE B 456 919 (47) Abstract:

A hydraulic percussion includes a cap (10) with a longitudinal bore (12), a cylinder sleeve (14), and a rear end piece (16) abutting the cylinder sleeve (14), a piston (15) reciprocated in the cylinder sleeve (14) for delivering blows to a working tool inserted into a guide sleeve (20) at the front of the bore (12), said guide sleeve (20) has radial openings (22a, b) for communicating lubricant from a lubricant channel (21) in the housing (10) to the inside of the guide sleeve (20), wherein the guide sleeve (20) is provided with external sealing rings (23ad) which form annular spaces between the lubricant channel (21) and the radial openings: »(22a, b) for spreading lubricant on the outer surface of the guide sleeve, a distribution valve (31) communicating with a the pressure medium source and the cylinder sleeve (14) and having both a gap seal (44) and a seat seal (45.46) for improved density, and a pressure accumulator (50) with an expansion chamber (52), wherein a movable diaphragm (59) is limited in its outward movement by a ball-shaped bulge (66) integrally formed with one of the walls (58) of the expansion chamber.

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Summary.

A hydraulic percussion includes a housing (10) with a longitudinal bore (12), a cylinder sleeve (14), and a rear end piece (16) abutting the cylinder sleeve (14), a piston (15) reciprocated in the cylinder sleeve (14) for delivering blows to a working tool inserted into a guide sleeve (20) at the front end of the bore (12), said guide sleeve (20) has radial openings (22a, b) for communicating lubricant from a lubricant channel (21) in the housing (10). ) to the inside of the guide sleeve (20), wherein the guide sleeve (20) is provided with external sealing rings (23ad) which form annular spaces between the lubricant channel (21) and the radial openings (22a, b) for spreading lubricant on the outer surface of the guide sleeve, a distribution valve (31) communicating with a pressure medium source and the cylinder sleeve (14) and having both a gap seal (44) and a seat seal (45,46) for improved tightness, and a pressure accumulator (50) with an expansion chamber (52), wherein a movable diaphragm (59) is limited in its outward movement by a ball-shaped bulge (66) integrally formed with one of the walls (58) of the expansion chamber.

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The present invention relates to a hydraulic breaker of the type comprising a housing with a longitudinal bore, a piston back and forth driven in the bore, a guide sleeve for receiving a working tool, and a lubricant supply channel in the housing communicating with radial openings in the guide sleeve for supply of lubricant. to the inside of the guide sleeve.

For a previously known breaking hammer of this type, see e.g. US 5,445,232, it is well known to apply lubricated grease to the inside of the tool sheath, but there is also a problem with the guide sleeve getting stuck in the housing. This means that after a period of use, there is a tendency for the guide sleeve to get stuck in the bore of the housing due to the frictional action during vibration movements of the guide sleeve. This results in difficulties in removing the guide sleeve from the housing for service, replacement and the like. Expensive efforts and time must be sacrificed just to remove the guide sleeve from the housing, which is completely unacceptable.

The main object of the invention is to create a break hammer of the type described above where the guide sleeve is prevented from being caught in the housing bore and removal of the guide sleeve from the housing bore is facilitated.

Further objects and advantages of the invention will be apparent from the following description and claims.

A preferred embodiment of the invention is described below with reference to the accompanying drawing.

Drawing:

Fig. 1 shows a longitudinal section through a hydraulic breaker according to the invention.

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Fig. 2 shows on a larger scale a section through the distribution valve of the breaker hammer in Fig. 1.

Fig. 3 shows on a larger scale a partial section through the tool sleeve of the breaking hammer in Fig. 1.

The hydraulic breaker hammer illustrated in the drawings includes a housing 10 formed with a rear mounting flange 11 for connection to a mechanical support such as an excavator arm. The housing 10 is provided with an elongated through bore 12 which carries in its rear part a cylinder sleeve 14 for sealing control of a piston 15. At the rear end of the housing 10 is screwed a end piece 16 which serves as the end closure of the bore 12. This end piece 16 is formed in one piece with a tubular neck portion 17 which extends into the bore 12 and abuts the rear end of the cylinder sleeve 14. The latter is held clamped in its position in the bore 12 between the end portion 17 of the end piece 17 and an abutment 18 in the bore 12. The neck portion 17 also forms a guide member for the piston 15 and carries a sealing ring 19 for engagement with the rear end of the piston 15.

At its forward end, the bore 12 carries a tool guide sleeve 20 which is arranged to receive the rear end of a working tool (not shown). For lubricating the inside of the guide sleeve 20, a supply channel 21 is provided in the housing 10 for lubricant which communicates via the radius of openings 22a, b, the guide sleeve 20 the inside of the sleeve 20. Furthermore, the guide sleeve 20 is provided on its outside with four O-rings 23 ad, the tasks of which are two, namely by holding friction engagement with the bore 12 to retain the guide sleeve 20 in the bore 12, and to seal between them two annular spaces 24,25. The apertures 22 a, b of the guide sleeve 20 are located between the O-rings 23 a, b and 23 c, d, respectively, so that lubricants must pass through the spaces 24,25 to reach the radial openings 22 a, b and the inside of the guide sleeve 20.

See Fig. 3. The spaces 24,25 are thus filled with lubricant

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P20-04804-050615 (grease), and thanks to the axial extension of the spaces 24,25, the lubricant is spread over a substantial portion of the outside of the guide sleeve 20, thereby preventing the guide sleeve 20 from becoming trapped in the bore 12.

The housing 10 includes an inlet channel 28 for pressure means for supplying pressure means to the cylinder sleeve 14 so as to drive the piston 15 in its reciprocating motion and to deliver blows to the working tool inserted in the control sleeve 20. The piston 15 has two opposite driving surfaces 29,30. , of which the lower surface 30 is continuously connected to the print media source, while the upper surface 29 is intermittently pressurized via a distribution valve 31. The distribution valve 31 has a media inlet 32 ​​communicating with the inlet duct 28, and a media outlet 33 communicating with the upper drive surface 29 of the piston 15. Further, the distribution valve 31 comprises a valve bore 35 and a valve member 34 which is sealedly controlled in the bore 35. The valve element 34 consists of a tubular guide portion 36 guided in the bore 35, and an end wall 37. In the end wall 37, openings 38 are provided for connecting the inside of the guide portion 36 and the media inlet 32 ​​to the outer surface of the end wall 37. The end wall 37 has a reduced diameter actuating member 40 which extends coaxially in a direction opposite the guide portion 36 and forms an intermittent portion. pressurized activation bore 41.

The end wall 37 has a slightly larger cross-sectional area than the guide portion 36, and since the valve member 34 has open ends, the pressure medium will act constantly both on the surface formed by the guide portion 36 and, via the openings 38, on the outer surface of the end wall 37. In the position where the activation bore 41 is connected to the tank, i.e. when no pressure acts on the actuating member 40, a closing force occurs on the valve member 34 since the remaining portion of the end wall 37 is smaller than the guide portion

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P20-04804-050615 surface. When instead the actuating bore 41 is pressurized, the total surface of the end wall 37 and the actuating part 40 will generate a force which will dominate the force generated by the action of the pressure medium on the surface of the control portion 36. This means that the valve member 34 is switched to its open position. (Not shown).

The valve element 34 is arranged to control the communication between the inlet 32 ​​and the outlet 33, and for this purpose the valve element 34 is designed with a double sealing function, namely both a gap seal and a seat seal. The seat seal is the primary seal and is formed by an annular seat 45 at the end of the bore 35 in cooperation with an annular contact surface 46 of the end wall 37. The gap seal is a secondary seal and is formed by a circumferential surface 44 of the end wall 37 in cooperation with the valve bore 35, as illustrated by the closed position shown in Fig. 1. By a combined gap seal and seat seal as described above, a high degree of seal of the valve is achieved, and thereby a high efficiency of the percussion.

The percussion shown in the drawing also includes pressure absorber accumulator 50 which is partly made up of percussion housing 10 and partly by a lid 51 mounted on housing 10. Accumulator 50 comprises an expansion chamber 52 which is conventionally divided by a flexible diaphragm 53 into a print media chamber 54 and a gas cushion chamber 55. The expansion chamber 52 is bounded by an inner wall 57 and an outer wall 58, the outer wall 58 being formed by the lid 51.

The accumulator also includes a movable diaphragm support 59 consisting of a stem portion 61 and a diaphragm supporting head 62. The latter is located in the print media chamber 54, while the stem portion 61 is slidably guided in a bore in

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P20-04804-050615 inner wall 57. Openings 64 are arranged parallel to stem portion 61 to communicate pressure medium into expansion chamber 52, and head 62 is arranged to cover these openings 64 at low pressure levels as diaphragm 53 is pressed against inner wall 57. A spring 65 is provided. arranged to exert an adjusting force on the membrane support 59 in the direction of the membrane 53. In order to limit the length of the guiding stem portion 61, a stop means in the form of a protrusion 66 is arranged on the outer wall 58 of the expansion chamber. This protrusion 66 is formed integrally with the lid 51. This movement limiting arrangement for the membrane support 59 is simple in its design. contains some extra details.

The lubrication arrangement for the guide sleeve according to the invention involves improved and simplified handling of the guide sleeve during service and replacement. However, the embodiments of the invention are not limited to the example described but can be freely varied within the scope of the claims.

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