INSERT BUSHING ARRANGEMENT, BREAKING HAMMER AND RELATED METHOD

Abstract

An insert bushing arrangement of a breaking hammer, a breaking hammer and a method of supporting a breaking tool of a breaking hammer is provided. The insert bushing arrangement includes a bearing support inside which an insert bushing is mountable. Between the bearing support and the insert bushing is one or more intermediate material layers for preventing jamming of the components.

Claims

1. An insert bushing arrangement of a breaking hammer comprising: an insert bushing mountable axially inside a bearing support, wherein an inner cylindrical surface of the insert bushing is arranged as a slide bearing surface against a breaking tool, which is movable relative to the insert bushing; an insert locking element configured to limit axial movement of the insert bushing relative to the bearing support; and an intermediate material layer disposed between opposing surfaces of the bearing support and the insert bushing.

2. The insert bushing arrangement as claimed in claim 1, wherein material of the intermediate material layer differs from materials of the bearing support and the insert bushing.

3. The insert bushing arrangement as claimed in claim 1, wherein the insert bushing includes a cylindrical intermediate element, which is a separate element mountable between the bearing support and the insert bushing and is configured to serve as the intermediate material layer.

4. The insert bushing arrangement as claimed in claim 3, wherein a thickness of the intermediate material layer is at least 0.5 mm.

5. The insert bushing arrangement as claimed in claim 3, wherein the cylindrical intermediate element includes an axial groove extending end to end and radially through the element.

6. The insert bushing arrangement as claimed in claim 3, wherein the insert bushing includes at least two intermediate segment elements, which are separate elements mountable between the bearing support and the insert bushing and are together configured to form a cylinder-like element and to serve as the intermediate material layer.

7. The insert bushing arrangement as claimed in claim 3, wherein the cylindrical intermediate element is a symmetrical piece, whereby a mounting direction of the element is freely selectable.

8. The insert bushing arrangement as claimed in claim 3, wherein the intermediate element is provided with at least one material layer serving as an isolating material layer between the intermediate element and at least one of the bearing support and the insert bushing.

9. The insert bushing arrangement as claimed in claim 1, wherein at least one of the bearing support and the insert bushing is provided with at least one coated intermediate material layer.

10. The insert bushing arrangement as claimed in claim 1, wherein the bearing support includes a frame bushing, which is mountable removably to a frame of the breaking hammer and a frame locking element arranged for locking the frame bushing to the frame of the breaking hammer, wherein the insert bushing is mountable axially inside the frame bushing, and wherein the inner cylindrical surface of the insert bushing serves as a slide bearing surface against a breaking tool, which is movable relative to the arrangement, the insert bushing being removable without dismounting the frame bushing.

11. The insert bushing arrangement as claimed in claim 1, wherein the bearing support includes a bearing housing formed directly to the frame of the breaking hammer and including support surfaces towards the insert bushing.

12. A breaking hammer, comprising: a percussion device including a frame and an impact element arranged inside the frame; a breaking tool connectable to the percussion device and arranged to protrude from the frame; a bearing support, which is located at a tool side end of the frame; and an insert bushing arrangement in accordance with claim 1 having at least an insert bushing mounted removably inside the bearing support, wherein inner surfaces of the insert bushing are configured to serve as slide bearing surfaces against the breaking tool.

13. A method of supporting a breaking tool of a breaking hammer, the method comprising: providing a tool side lower end of the breaking hammer with at least one insert bushing; arranging the insert bushing inside a bearing support of the breaking hammer; retaining the insert bushing by means of an insert locking element inside the bearing support; providing the breaking hammer with an intermediate material layer between the bearing support and the insert bushing and thereby isolating the bearing support and the insert bushing from direct material contact at least at a slide bearing zone therebetween; and selecting material properties between the intermediate material layer and the bearing support, and further, between the intermediate material layer and the insert bushing to have a poor mutual adhesion tendency and to thereby prevent sticking of the materials.

14. The method according to claim 13, further comprising preventing axial movement of the insert bushing in axial direction by means of a locking ring.

15. The method according to claim 13, further comprising using a frame bushing as the bearing support; and removing the insert bushing without removing the frame bushing and executing the removal at a work site of the breaking hammer.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0055] Some embodiments are described in more detail in the accompanying drawings, in which

[0056] FIG. 1 is a schematic side view of an excavator, which is provided with a breaking hammer.

[0057] FIG. 2 is a schematic and cross-sectional side view of a percussion device of a breaking hammer.

[0058] FIG. 3 is a schematic side view of an insert bushing arrangement including three components of a frame bushing, a cylindrical intermediate element and an insert bushing.

[0059] FIG. 4 is a schematic and partial cross-sectional side view of an insert bushing arrangement in a situation where the components are mounted one inside another.

[0060] FIG. 5 is a schematic and partly cross-sectional view of an alternative insert bushing arrangement, wherein an insert bushing and a cylindrical intermediate element have been mounted inside a bearing housing formed to a lower end of the frame of the breaking hammer.

[0061] FIG. 6 is a schematic longitudinal view of a cylindrical intermediate element provided with a longitudinal slit.

[0062] FIG. 7 is a schematic longitudinal view of a cylindrical intermediate element having two halves.

[0063] FIG. 8 is a schematic cross-sectional view of a cylindrical intermediate element comprising a ring-shaped frame made of base material and a coating on an outer surface of the frame.

[0064] FIG. 9 is a schematic longitudinal view of a bearing housing provided with a coating and further showing an insert bushing mountable inside the bearing housing.

[0065] For the sake of clarity, the figures show some embodiments of the disclosed solution in a simplified manner. In the figures, like reference numerals identify like elements.

DETAILED DESCRIPTION

[0066] FIG. 1 shows a breaking hammer 1 arranged on a free end of a boom 2 in a working machine 3, such as an excavator. Alternatively, the boom 2 may be arranged on any movable carriage or on a fixed platform of a crushing apparatus. The breaking hammer 1 includes a percussion device 4 for generating impact pulses.

[0067] The breaking hammer 1 may be pressed by means of the boom 2 against material 5 to be broken and impacts may be simultaneously generated with the percussion device 4 to a tool 6 connected to the breaking hammer 1. The tool 6 transmits the impact pulses to the material 5 to be broken. The percussion device 4 may be hydraulic, whereby it may be connected to the hydraulic system of the working machine 2. Alternatively, the percussion device 4 may be electrically or pneumatically powered.

[0068] The impact pulses may be generated in the percussion device 4 by means of a percussion element, such as a percussion piston, which may be moved back and forth in the impact direction and return direction under the influence of hydraulic fluid. Further, the breaking hammer 1 may have a protective casing 7, inside which the percussion device 4 may be located. At a lower end of the breaking hammer, i.e., at the tool side end, is an insert bushing arrangement 8 for bearing the tool 6 to a frame of the breaking hammer. The insert bushing arrangement 8 includes a bearing support, such as frame bushing, an intermediate material layer and an insert bushing described further herein.

[0069] FIG. 2 discloses a structure of a percussion device 4 of a breaking hammer 1. The breaking hammer has a lower end A at a tool side end and an upper end B. A percussion device 4 may include a percussion piston 9 arranged to move to and fro relative to a frame 10 of the percussion device 4. An impact surface 11 of the percussion piston 9 is arranged to strike an upper end of a tool, which is not shown in FIG. 2. The tool is allowed to move in the axial direction P during the use. The frame 10 may have an upper frame part 10a and a lower frame part 10b.

[0070] At the lower end of the lower frame part 10b of the breaking hammer 1 is a bushing housing 12 configured to receive an insert bushing arrangement 8, which serves as a lower tool bushing. The tool is also supported by means of an upper tool bushing 13, which is mounted in place when the lower frame 10b is detached. The tool is configured to pass through the lower and upper tool bushings 8, 13, which both serve as bearing and support elements for the tool. However, the lower tool bushing 8 is subjected to greater mechanical forces and wear than the upper tool bushing 13, whereby the lower tool bushing 8 needs to be serviced and changed more often. Since the bushing housing 12 of the lower tool bushing 8 opens towards the lower end A of the breaking hammer 1, components of the insert bushing arrangement 8 can be dismounted without dismantling the basic structure of the frame 10.

[0071] The mentioned insert bushing arrangement 8 includes a frame bushing 14, which serves as a bearing support for an insert bushing 15 mounted inside the frame bushing 14. The frame bushing 14 may be locked to the lower frame part 10b by means of a transverse locking pin 16.

[0072] FIG. 3 is an exploded view of an insert bushing arrangement 8 and FIG. 4 is an assembled view of the same. The insert bushing arrangement 8 includes a frame bushing 14, an insert bushing 15 and an intermediate material layer 17. The frame bushing 14 may have at least one transverse groove 18 on its outer surface in order to be locked by means of a locking pin to a frame of a breaking hammer.

[0073] The insert bushing 15 is mountable axially inside an opening 19 of the frame bushing 14. The intermediate material layer 17 may be a cylindrical or sleeve-like element 17a, which is mountable axially between the frame bushing 14 and the insert bushing 15. The insert bushing 15 and the cylindrical intermediate element 17a may be locked axially to the frame bushing 14 by means of an insert locking element 20, which may be a locking ring, for example. The intermediate element 17a may be cut in the axial direction so that it has an axial groove 21 or slit, which facilitates mounting of the intermediate element 17a. The wall thickness of the intermediate element 17a is relatively small compared to the wall thickness of the bushings 14 and 15. The lengths of the components 14, 15 and 17a correspond substantially to each other.

[0074] An inner surface 22 of the insert bushing 15 serves as a slide bearing surface facing a breaking tool. The insert bushing 15 is provided with a lubricating groove 23 and radial openings 24 for allowing lubricant to pass to the bearing surfaces. For the same reason, the intermediate element 17a includes matching openings 25, and the frame bushing 14 is provided with a lubrication groove 26 and radial openings 27.

[0075] The intermediate element 17a isolates an outer surface 29 of the insert bushing 15 and an inner surface 30 of the frame bushing 14 from direct contact and thereby prevents the bushings 14, 15 from jamming There exists minor movements between the surfaces 29 and 30 during the use of the breaking hammer and this may cause the jamming and may thereby make removal of the insert bushing 15 difficult in work site conditions. The jamming phenomena ruins the basic principle of the easily changeable insert bushing.

[0076] The pre-assembled structure shown in FIG. 4 may be mounted easily and fast in place and when a need exists the insert bushing 15 and the intermediate element 17a may be substituted without a need to remove the frame bushing 14. Due to the use of the intermediate material layer 17, the removal of the insert bushing 15 can be done using simple and light-weight hand tools.

[0077] FIG. 5 discloses an alternative solution, which differs from the one shown in FIGS. 2-4 in that there is no frame bushing, but instead a bearing housing 31 serves as bearing support and receives the insert bushing 15 and the intermediate element 17a. The bearing housing 31 is formed directly to a frame 10 of the breaking hammer. In some cases, the intermediate material layer 17 may include a coating on surfaces of the bearing housing 31.

[0078] At a lower end of the frame 10 may be a sealing bushing or element 32, which includes a frame 33 and one or more tool seals 34. FIG. 5 further discloses a lubricating channel 35 for conveying lubricant between the insert bushing arrangement 8 and the breaking tool 6.

[0079] FIG. 6 discloses a cylindrical intermediate element 17a provided with a longitudinal groove 21, slit or cutting.

[0080] In FIG. 7 the intermediate element 17a has two halves 17b and 17c. The halves 17b, 17c are dimensioned so that when the halves are set to correspond diameter of the bearing support, there are two slits 21 between their ends.

[0081] FIG. 8 discloses an intermediate element 17a including a ring-shaped frame 36 made of base material, such as aluminum alloy, and a coating 37, such as an anodization layer, on an outer surface of the frame 36. In other words, the element 17a may have bi-material configuration.

[0082] FIG. 9 discloses a bearing housing 31 provided with a coating 38. The coating 38 may serve as an intermediate material layer between an insert bushing 15 mountable inside the bearing housing 31.

[0083] The bearing support and its different embodiments are marked with reference markings BS in FIGS. 2-5 and 9.

[0084] Although the present embodiment(s) has been described in relation to particular aspects thereof, many other variations and modifications and other uses will become apparent to those skilled in the art. It is preferred therefore, that the present embodiment(s) be limited not by the specific disclosure herein, but only by the appended claims.