Method for supporting the breaking hammer and striking piston

Abstract

To provide an improved breaking hammer and a method of supporting a striking piston.SOLUTION: The breaking hammer comprises a striking device 4 provided with a reciprocating piston 9. The piston is supported to a frame at its end portions by means of a first piston bearing element 19 and a second piston bearing element 20. The second piston bearing element comprises a collar sealing element 13 facing toward a working collar 10 of the piston. The piston bearing elements are easily mountable and dismountable separate components.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a hydraulic breaking hammer, which comprises a striking device with a striking piston, the striking piston being supported by a bearing inside a frame of the striking device so as to be axially movable.

[0002] The present invention further relates to a method for supporting the piston of the striking device of a hydraulic breaking hammer.

[0003] The field of the invention is defined more particularly in the preambles of the independent claims. [Background technology]

[0004] The demolition hammer is used to destroy hard materials such as rock, concrete, etc. The demolition hammer comprises a striking device for generating an impact pulse to a demolition tool connectable to the demolition hammer. The striking device comprises a piston arranged axially movably inside a frame of the striking device. The piston is supported by a bearing relative to the frame of the striking device. Known bearing solutions exhibit several drawbacks. Summary of the Invention

[0005] SUMMARY OF THE INVENTION It is an object of the present invention to provide a new and improved breaking hammer and method of supporting a striking piston.

[0006] The breaking hammer according to the invention is characterized by the characterizing features of the independent device claim.

[0007] The method according to the invention is characterized by the characterizing features of the independent method claim.

[0008] The disclosed solution concept involves a piston of the percussion device supported at its distal end by a bearing, and an intermediate portion of the piston that provides a pressure surface for the piston to move in the impact and return directions. At the return end is a sleeve-like second piston bearing element. This element, or bushing, is a separate component that can be integrally attached to the frame of the percussion device. The second bearing element is a dual-purpose element that not only bears but also seals the piston. For sealing purposes, the second piston bearing element is provided with a seal housing for receiving a collar seal element. The collar seal element seals the radial gap between the radial outer surface of the actuation collar and the inner surface of the second piston bearing element. The collar seal element is a replaceable component.

[0009] The advantage of the disclosed solution is that the separate second piston bearing element can be easily and quickly attached and detached from the frame of the impact device. Furthermore, the piston bearing is located at the distal end of the piston, providing good support for the piston. The disclosed structure also allows for a reduction in the overall length of the impact piston and the entire impact device, which has a positive effect on the handling and weight of the demolition hammer.

[0010] According to one embodiment, the seal housing is disposed at the tool-side end of the second bearing element and includes a seal groove on the inner surface of the second bearing element. The collar seal element is a slide ring mounted in the seal groove. Replacement of the seal ring is easy when the second bearing element is first removed from the frame.

[0011] According to one embodiment, the aforementioned slide ring is made of a plastic material having good sliding bearing properties.

[0012] According to one embodiment, the second piston bearing element is provided with a dedicated lubrication channel.

[0013] According to one embodiment, hydraulic fluid is continuously supplied to the second bearing during the operating cycle through a lubrication channel. The lubrication channel may be connected, for example, to a high-pressure accumulator. The lubricant can lubricate and cool the bearing. Proper lubrication of the bearing prevents the striking device from seizing under harsh conditions and use.

[0014] According to one embodiment, the second bearing element is provided with a dedicated reservoir channel, the reservoir channel is provided with a restriction, and the reservoir channel is connected to the reservoir, the reservoir channel can release pressure from the area between the seals to the reservoir and can also provide lubrication to the seals.

[0015] According to one embodiment, the second piston bearing element is provided with an end cushion space that, together with the working collar, forms a closed pressure space when the piston's return movement exceeds a predetermined dead center where the piston transitions between return and impact movement. In other words, the second piston bearing element or bushing located at the return end of the percussion device may be a triple-purpose element that provides bearing, sealing, and deceleration for the piston.

[0016] According to one embodiment, the first and second piston bearings mentioned above are both replaceable elongated bearing bushings.

[0017] According to one embodiment, the bearing bushing is made of tempered steel. Alternatively, the bearing bushing may be made of other metallic materials such as bronze or cast iron.

[0018] According to one embodiment, the first bearing bushing includes at least one seal housing with at least one seal facing the piston, and the first bearing bushing located at the impact end of the striking device is therefore also an easily replaceable component, facilitating maintenance.

[0019] According to one embodiment, the percussion device includes a direct-acting pressure accumulator arranged at the return end of the piston and configured to accumulate pressure energy when the second end of the piston projects into the accumulator during its return movement. The second seal housing faces the piston and includes a gas seal element that fluid-tightly separates the bearing portion of the second piston bearing element and the pressure accumulator from each other. The second piston bearing element is provided at its second end with a second seal housing that faces the pressure accumulator and can receive a gas seal. In other words, the second piston bearing element or bushing arranged at the return end of the percussion device is a quadruple-purpose element that provides bearing, hydraulic sealing, deceleration, and gas sealing for the piston.

[0020] According to one embodiment, the second working pressure space located on the return side is limited only by the piston and the second piston bearing element. In other words, the second piston bearing element or bushing located at the return end of the percussion device is a five-purpose element that provides bearing for the piston, hydraulic sealing, deceleration, gas sealing and limiting the second working pressure space.

[0021] According to one embodiment, the first and second piston bearings are both replaceable elongated bearing bushings. The outer diameters of the bushings radially opposed to the frame are equal. Furthermore, the frame of the striking device has a central through-hole, and at least both ends of the central through-hole have equal, coaxial inner diameters that match the outer diameters of the bearing bushings. Therefore, the inner diameters of both ends of the frame can be precisely machined on a single machine using a single fastener, thereby ensuring that the bearing support surfaces are coaxial.

[0022] In one embodiment, the frame of the striking device has a middle section between the end sections, the inner diameter of which is equal to the diameter of the end sections. In other words, there are three bores with the same diameter. This simplifies the construction of the piston bearing elements and facilitates machining of the frame.

[0023] According to one embodiment, the machined inner diameters of the through openings in the frame of the percussion device are all coaxial and have the same diameter, which is advantageous for ease of manufacture.

[0024] According to one embodiment, the control device is configured to direct a substantially constant hydraulic fluid pressure to a first working pressure space for moving the piston in a return direction, and is configured to supply and release hydraulic fluid pressure to and from a second working pressure space, thereby controlling the reciprocating movement of the piston during a working cycle. In other words, the percussion device provides alternating pressure conditions (high pressure - tank pressure) on the impact side of the piston.

[0025] According to one embodiment, the operating principle of the impact device differs from that disclosed in the above embodiment. The impact device may alternatively have alternating high-pressure-tank pressure conditions that affect the return movement of the piston and a substantially constant high-pressure condition that pushes the piston in the impact direction. A further alternative is a solution in which the alternating high-pressure-tank pressure conditions are controlled during the actuation cycle in both directions of movement. These disclosed alternative solutions may also utilize the piston bearing and sealing solutions and other features disclosed herein.

[0026] According to one embodiment, the solution relates to a method for supporting a piston of a hydraulic breaking hammer, the method comprising: supporting the piston axially movably relative to a frame of the impacting device of the breaking hammer by a first piston bearing and a second piston bearing; and sealing the working pressure spaces of the impacting device from each other by a sealing element arranged on the working collar of the piston. The method further comprises: arranging the first piston bearing at a tool end of the piston and the second piston bearing at an opposite return end of the piston; using a separate sleeve-shaped bearing bushing for at least the second piston bearing element; providing a first seal housing facing the piston for the second piston seal bushing; attaching a replaceable collar seal element to the first seal housing; and attaching the second piston bearing bushing together with the collar seal element to the frame of the impacting device, the second piston bearing element providing a bearing and a seal for the piston.

[0027] According to one embodiment, the method includes providing a striking device with a tubular frame having a through-hole, with both ends having coaxial and equal-sized inner diameters. Separate first and second piston bearing bushings are axially pressed into the ends of the through-hole. All seals in the piston bearing bushings are installed and removed when the bushings are removed from the frame, thereby facilitating maintenance and repair work.

[0028] The above disclosed embodiments can be combined to form a desired solution with the required features disclosed.

[0029] Some embodiments are explained in more detail in the accompanying drawings. [Brief explanation of the drawings]

[0030] [Figure 1] 1 is a schematic side view of an excavator equipped with a demolition hammer; [Figure 2]1 is a schematic cross-sectional side view of a hydraulically operated impact device of a breaking hammer. [Figure 3] 10 is a schematic partial cross-sectional side view of a second piston bearing bushing that can be mounted on the opposite end of the striking device. FIG. [Figure 4] FIG. 4 is a schematic view of the second piston bearing bushing of FIG. 3. [Figure 5] 1 is a schematic view of a first piston bearing bushing that can be mounted on the tool end of the striking device. FIG. [Figure 6] 1 is a schematic diagram illustrating some of the problems and features of the disclosed second piston bearing bushing. [Figure 7] FIG. 2 is a schematic cross-sectional side view of the frame of the striking device. DETAILED DESCRIPTION OF THE INVENTION

[0031] For clarity, the figures show some embodiments of the disclosed solution in a simplified manner.In the drawings, like reference numerals denote like elements.

[0032] FIG. 1 shows a demolition hammer 1 arranged at the free end of a boom 2 of a work machine 3, such as an excavator. Alternatively, the boom 2 may be arranged, for example, on any mobile carriage or on a fixed base of a crushing device. The demolition hammer 1 comprises an impact device 4 for generating an impact pulse. The demolition hammer 1 may be pressed by the boom 2 against the material 5 to be destroyed, and an impact may be generated simultaneously with the impact device 4 against a tool 6 connected to the demolition hammer 1. The tool 6 transmits the impact pulse to the material 5 to be destroyed. The impact device 4 is hydraulic and is thereby connected to the hydraulic system of the work machine 2. The impact pulse is generated in the impact device 4 by a striking piston that is moved back and forth in an impact direction A and a return direction B under the influence of a hydraulic fluid. Furthermore, the demolition hammer 1 may comprise a protective casing 7 in which the impact device 4 can be arranged. The impact device 4 may comply with the solutions disclosed herein.

[0033] 2 discloses the basic structure of the impact device 4 of the breaking hammer. The impact device 4 comprises a frame 8, inside which a striking piston 9 is arranged so as to move in an impact direction A and a return direction B. The piston 9 comprises an actuating collar 10 in its middle. On the impact direction A side of the collar 10 there is a first working pressure space 11, and on the return direction B side there is a second working pressure space 12, inside which the pressure of the hydraulic fluid is controlled by a control device CD. The working pressure spaces 11, 12 are separated from each other by a collar seal element 13. A gap 14 or annular gap surrounds the actuating collar 10, and this gap 14 is sealed by the collar seal element 13.

[0034] The piston 9 comprises a first working pressure surface 15 for moving the piston 9 in the return direction B and a second working pressure surface 16 for moving the piston 9 in the impact direction A. The control device CD is able to alternate the pressure in the second working pressure space 12 by connecting the second pressure space to a tank T or a pressure source PS. The control device CD is able to connect the first working pressure space 11 to the pressure source during the working cycle. The effective area of ​​the second working pressure surface 16 is greater than the area of ​​the first working pressure surface 15, so that the supply of high pressure to the second working pressure space 12 moves the piston in the impact direction A. It should be noted that the pressure flow control and the effective area of ​​the working pressure surfaces can also be arranged and dimensioned in other ways, as already mentioned above in this specification.

[0035] The striking piston 9 is supported on the frame 8 by a first piston bearing 17 and a second piston bearing 18. The first and second piston bearings 17, 18 are separate sleeve-like piston bearing elements 19, 20 that can be axially mounted inside a central through-hole 21 in the frame 8. The first piston bearing element 19 supports the piston 9 at the lower end of the striking device 4, and the second piston bearing element 20 supports it at the upper end. The piston bearing elements 19, 20, or bushings, are provided with one or more hydraulic seals 22, 23 for sealing the inner diameter of the piston bearing element 19, 20 to the outer diameter of the piston 9. In addition to these seals and sealing portions, the piston bearing elements 19, 20 include bearing portions 24, 25 for providing plain bearings at both ends of the piston 9. The piston bearing elements 19, 20 may also include end cushion spaces 26, 27 that form closed pressure spaces with the working pressure surfaces 15, 16 when the piston exceeds its normal stroke length in the impact direction A and return direction B. As can be seen, the second working pressure space 12 may be defined between the piston 9 and the second piston bearing element 20. The bearing portion 25 of the second bearing element 20 may be provided with a dedicated lubrication channel 28 for providing lubrication from a lubrication source L for the plain bearing surface. Both piston bearing elements 19, 20 may be provided with dedicated tank channels 29, 30 equipped with a throttling device 31 and connected to a tank T.

[0036] The striking piston 9 has an impact surface 32 facing in the impact direction A and configured to strike the tool. A rear surface 33 of the piston 9 faces in the return direction B and is configured to move in a gas space 34 of a direct acting pressure accumulator 35. At the end of the sealing part of the second piston element 20 there is a gas sealing element 36 for separating the bearing part 25 and the gas space 34 from each other in a fluid-tight manner.

[0037] The control device CD may be, for example, a control valve, a control valve assembly, or a set of directly or indirectly controlled valve elements. The control device CD may comprise one or more control elements that move along a linear or rotary control path and control one or more of the control pressure channels.

[0038] FIG. 2 further discloses the axial mounting directions M1 and M2 of the piston bearing elements 19, 20 inside the through openings 21 of the frame 8.

[0039] 3 and 4 show a second piston bearing element 20 substantially identical to that shown in FIG. 2. FIG. 3 further shows a seal housing 23' for receiving a hydraulic seal element. The seal housing 23' may have grooves 23a and 23b. The seal housing 36' for the gas seal element may have a seal groove 36a. The seal housing 13' for receiving an actuating collar seal element may have a seal groove 13a. Furthermore, the outer surface of each end of the second piston bearing sleeve 20 may have seal grooves 37 and 38 for receiving outer seal elements facing the longitudinal through-openings in the frame. The bushing 20 may have several transverse openings 39 for supplying hydraulic fluid through the sleeve-like structure.

[0040] Figure 5 discloses a first piston bearing element 19 according to that shown in Figure 2. Inside the element 19 there is a seal housing 22' for the hydraulic seal and on the outer surface there is a seal groove 40 for the outer seal element.

[0041] The first and second piston bearing elements 19, 20 can be pre-assembled by providing them with sealing elements. Mounting the sealing elements on separate bushings is much easier than mounting them on the complete striking device structure.

[0042] The features disclosed in FIG. 6 have already been described herein above.

[0043] FIG. 7 shows an elongated sleeve-like frame 8 of a percussion device, with a central opening 21 provided with equal, coaxial inner diameters D1 and D2. The diameters D1 and D2 correspond to the equal outer diameters of the first and second piston elements 19 and 20. Therefore, the bearing bushings 41 and 42 for receiving the bearing bushings 19 and 20 have equal diameters. Furthermore, the middle of the frame may have a third section 43 configured to receive the lower end portion of the bushing 20. The inner diameter D3 of the third section 43 may also have the same diameter as the end diameters D1 and D2. All diameters D1, D2, and D3 are also coaxial. Between the precise sections 41, 42, and 43, there may be an unmachined section that serves as a chamber for the pressure connection P. As can be seen, the structure of the frame 8 is relatively simple and easy to manufacture.

[0044] The drawings and the associated description are intended only to illustrate the concept of the invention, in details which may vary within the scope of the claims. [Explanation of symbols]

[0045] 1 Destruction Hammer 2. Boom 3. Work machinery 4. Percussion device 5 Material 6 Tools 7 Protective casing 8 frames 9 Striking Piston 10 Actuation Color 11 First working pressure space 12 Second working pressure space 13 Color Seal Elements 13' Seal Housing 13a Seal groove 14 Gap 15 first working pressure surface 16 Second working pressure surface 17 First piston bearing 18 Second piston bearing 19 First piston bearing element, bearing bushing 20 Second piston bearing element, bearing bushing, second piston bearing sleeve 21 Central through opening 22 Hydraulic seal 22' Seal Housing 23 Hydraulic seal 23' Seal Housing 23a Groove 23b Groove 24 Bearing section 25 Bearing section 26 End cushion space 27 End cushion space 28 Lubrication Channels 29 Dedicated Tank Channel 30 Dedicated Tank Channel 31 Aperture device 32 Impact Surface 33 Rear 34 Gas Space 35 Direct acting pressure accumulator 36 Gas seal element 36' Seal Housing 36a Seal groove 37 Seal groove 38 Seal groove 39 Lateral opening 40 Seal groove 41 Bearing bushing 42 Bearing bushing 43 Third Section A Impact direction B Return direction CD control unit D1 Coaxial inner diameter D2 Coaxial inner diameter D3 inner diameter L Lubricant source M1 Axial installation direction M2 Axial installation direction P pressure connection PS pressure source T Tank

Claims

1. A hydraulic breaking hammer (1), a percussion device (4) comprising a frame (8) and a piston (9) arranged inside the frame (8), the percussion device (4) being configured to perform a working cycle including reciprocating longitudinal movements of the piston (9) in an impact direction (A) and a return direction (B) by means of the pressure of a hydraulic fluid supplied to a first working pressure space (11) and a second working pressure space (12) of the percussion device (4); at least one control device (CD) for controlling the supply and discharge of said hydraulic fluid to at least one of said first working pressure space (11) and said second working pressure space (12) for carrying out said working cycle; an actuation collar (10) of the piston (9) disposed between the first actuation pressure space (11) and the second actuation pressure space (12), the outer surface of the actuation collar (10) being sealed by a collar seal element (13) so that the first actuation pressure space (11) and the second actuation pressure space (12) are hydraulically separated; a first piston bearing (17) and a second piston bearing (18) arranged at an axial distance from each other; Equipped with the first piston bearing (17) and the second piston bearing (18) are configured to provide support for opposite first and second ends of the piston (9), such that the first working pressure space (11), the working collar (10) and the second working pressure space (12) are all located between the first piston bearing (17) and the second piston bearing (18); At least the second piston bearing (18) is a second piston bearing element (20) that is integrally mountable to the frame (8); a radial gap (14) between an outer surface of the operating collar (10) and the second piston bearing element (20), and at least one collar seal element (13) is arranged to seal the gap (14); The second piston bearing element (20) comprises at least one first seal housing (13') for the collar seal element (13). A destructive hammer (1) characterized by:

2. the first seal housing (13') is disposed at the tool side end of the second piston bearing element (20) and has a seal groove (13a) on the inner surface of the second piston bearing element (20); The color seal element (13) is a slide ring attached to the seal groove (13a).

2. The breaking hammer according to claim 1,

3. The second piston bearing element (20) is provided with a dedicated lubrication channel (28).

3. A demolition hammer according to claim 1 or 2, characterized in that:

4. The second piston bearing element (20) is provided with an end cushion space (27), and the end cushion space (27) is configured to form a closed pressure space together with the operating collar (10) when the piston (9) travels beyond a predetermined dead center at which the movement of the piston in the return direction (B) changes between the movement in the return direction and the movement in the impact direction (B, A). A breaking hammer according to any one of claims 1 to 3, characterized in that

5. The first piston bearing (17) and the second piston bearing (18) are both replaceable elongated bearing elements (19, 20). A breaking hammer according to any one of claims 1 to 4, characterized in that

6. the impact device (4) comprises a direct acting pressure accumulator (35), the direct acting pressure accumulator (35) being arranged at the return direction (B) end of the piston (9) and configured to accumulate pressure energy when the second end of the piston (9) protrudes into the direct acting pressure accumulator (35) during its movement in the return direction (B); the second piston bearing element (20) is provided with at least one second seal housing (36') at its second end facing the direct acting pressure accumulator (35); The second seal housing (36') is provided with a gas seal element (36) that faces the piston (9) and fluid-tightly separates the bearing portion (25) of the second piston bearing element (20) and the direct acting pressure accumulator (35) from each other. A breaking hammer according to any one of claims 1 to 5, characterized in that

7. The second working pressure space (12) arranged on the return direction (B) side is limited only by the piston (9) and the second piston bearing element (20). A breaking hammer according to any one of claims 1 to 6, characterized in that

8. the first piston bearing (17) and the second piston bearing (18) are both replaceable elongated bearing elements (19, 20), and the bearing elements (19, 20) radially facing the frame (8) have the same outer diameter; The frame (8) of the percussion device (4) is provided with a central through-opening (21), at least both ends of which have coaxial inner diameters (D1, D2), which are equal in size and coincide with the outer diameters of the bearing elements (19, 20), which are equal in size. A breaking hammer according to any one of claims 1 to 7, characterized in that

9. the control device (DC) is configured to direct a substantially constant hydraulic fluid pressure to a first working pressure space (11) for moving the piston (9) in the return direction (B), and is configured to control the reciprocating movement of the piston (9) during a working cycle by supplying and releasing hydraulic fluid pressure to and from the second working pressure space (12). A breaking hammer according to any one of claims 1 to 8, characterized in that

10. A method for supporting a piston (9) of a hydraulic breaking hammer (1), comprising: supporting the piston (9) axially movably relative to the frame (8) of the striking device (4) of the breaking hammer (1) by a first piston bearing (17) and a second piston bearing (18); sealing the working pressure spaces (11, 12) of the percussion device (4) from each other by means of a collar seal element (13) arranged on the working collar (10) of the piston (9); Including, The first piston bearing (17) is disposed at an end of the piston (9) on the impact direction (A) side, and the second piston bearing (18) is disposed at an opposite end of the piston (9) on the return direction (B) side; using a second piston bearing element (20) for at least said second piston bearing (18); providing said second piston bearing element (20) with a first seal housing (13') facing said piston (9); receiving the replaceable collar seal element (13) in the first seal housing (13'); mounting the second piston bearing element (20) on the frame (8) of the striking device (4), the second piston bearing element (20) providing a bearing and a seal for the piston (9); A method characterized by:

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