Abstract
A body of an impact unit, an impact unit and a method of forming a body of an impact unit is disclosed. The body can be an elongated hollow piece including at least two body parts. The body parts are arranged successively in an axial direction of the body and are connected to each other by axial connecting joints. The connecting joints include several slanted fastening screws for connecting the body parts together.
Claims
1. A body of an impact unit, comprising: an elongated hollow piece having a first end and a second end and an inner space inside which operable elements of an impact unit are mountable; at least two body parts arranged successively in an axial direction of the body, each of the body parts having axial connecting surfaces; and an axial connecting joint disposed between the at least two successive body parts, the connecting joint including a plurality of fastening screws, wherein the connecting surfaces of the body parts face towards each other and are pressed towards each other by the fastening screws, wherein the fastening screws are slanted relative to an axial direction of the body.
2. The body as claimed in claim 1, wherein the fastening screws have first end portions provided with turning heads and second end portions provided with threads, wherein the fastening screws are slanted so that longitudinal axes of the fastenings screws are at the threaded second end portions, the second end portions being closer to a central axis of the body then the first end portions provided with the turning heads.
3. The body as claimed in claim 2, wherein the turning heads of the fastening screws of the connecting joint face towards the second end of the body.
4. The body as claimed in claim 2, wherein the turning heads of the fastening screws of the connecting joint face towards the first end of the body.
5. The body as claimed in claim 2, wherein the connecting joint includes at least one first fastening screw facing towards the first end and at least one second fastening screw facing towards the second end.
6. The body as claimed in claim 2, wherein the fastening screws each have an angle relative to a normal of the axial connecting surfaces of the connecting joint, a magnitude of the angle being between 5-15°.
7. The body as claimed in claim 1, wherein the fastening screws include turning heads provided with flat first support surfaces facing towards the axial connecting joint, the axial connecting joint including a support flange on a side of the turning heads, the support flange being provided with openings through which the fastening screws pass, the connecting joint having several flat second support surfaces located at the openings, the flat second surfaces are facing towards the flat first support surfaces of the fastening screws, and wherein the flat first support surfaces and the flat second support surfaces are perpendicular relative to the longitudinal axis of the slanted fastening screws, the flat first support surfaces and the flat second support surfaces being pressed against each other when the fastening screws are tightened.
8. The body as claimed in claim 7, wherein the connecting joint includes a first support flange located at one end of the body part and being provided with an annular first connecting surface facing towards another body part, the first support flange having an annular supplementary surface located on an opposite side of the first support flange, the annular supplementary surface of the first support flange being slanted relative to a line perpendicular to an axial center line of the body, and wherein the slanted annular supplementary surface is provided with several flat second support surfaces for supporting the turning heads of the fastening screws.
9. An impact unit comprising: a body; an impact device located inside the body; and a coupling means device disposed at one end of the body and arranged to connect a tool to the impact unit, the body being an elongated hollow piece having a first end and a second end and an inner space inside which operable elements of an impact unit are mountable, at least two body parts arranged successively in an axial direction of the body, each of the body parts having axial connecting surfaces, and an axial connecting joint disposed between the at least two successive body parts, the connecting joint including a plurality of fastening screws, wherein the connecting surfaces of the body parts face towards each other and are pressed towards each other by the fastening screws, wherein the fastening screws are slanted relative to an axial direction of the body.
10. The impact unit as claimed in claim 9, wherein the impact unit is implemented in a breaking hammer.
11. The impact unit as claimed in claim 9, wherein the impact unit is implemented in a rock drilling machine.
12. A method of forming a body of an impact unit, the method comprising: forming at least two separate elongated hollow body parts; providing the body parts with axial connecting surfaces; arranging the body parts axially successively; and pressing the axial connecting surfaces of the body parts towards each other and fastening the body parts together by several slanted fastening screws, wherein a direction of the slanted fastening screws deviates from axial direction of the body.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0043] FIG. 1 is a schematic and sectional side view of a breaking hammer, which is provided with an impact device arranged inside a longitudinal body.
[0044] FIG. 2 is a schematic and sectional side view of an alternative body of a breaking hammer,
[0045] FIGS. 3-5 are schematic and sectional side views of some feasible axial connecting joints,
[0046] FIG. 6 is a schematic and partly sectional axial view of a body part provided with a support flange and flat support surfaces located at screw holes,
[0047] FIG. 7 is a schematic axial view of a rectangular support flange of a body part,
[0048] FIG. 8 is a schematic side view of the rectangular flange shown in FIG. 7, and
[0049] FIG. 9 is a schematic side view of a fastening screw.
[0050] 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.
[0051] The foregoing summary, as well as the following detailed description of the embodiments, will be better understood when read in conjunction with the appended drawings. It should be understood that the embodiments depicted are not limited to the precise arrangements and instrumentalities shown.
DETAILED DESCRIPTION OF SOME EMBODIMENTS
[0052] FIG. 1 discloses a basic structure of a breaking hammer 1. The breaking hammer 1 includes a first end A, or front end, at a tool 2 side end, and a second end B, or rear end, at the opposite end. At the second end B may be mounting means for connecting the breaking hammer 1 to a boom of working machine. The breaking hammer 1 includes an elongated body 3. The body 3 may be surrounded by means of a protective casing 4. The body 3 is a hollow structure, whereby it is provided with an inner space for receiving an impact device ID inside the body 3. The impact device ID may include a percussion piston 5 and a pressure accumulator 6. The percussion piston 5 is arranged to move longitudinally C to and fro relative to the body 3 by directing pressurized fluid to working pressure spaces 7, 8 inside the body. Transverse fluid channels FC may open to inner surfaces defining the pressure spaces. An impact surface 9 of the percussion piston 5 is arranged to strike an upper end 10 of the breaking tool 2. Thus, inside the body 3 are located operable elements of the impact unit for generating impact pulses to the tool 2.
[0053] In FIG. 1 the body 3 includes three body parts 11 instead of one single uniform body structure. A first main body part 11a is located at the first end A side of the body 3 and a second main body part 11b is connected to a rear end of the first main body part 11a. Further, an end body part 11f is connected to a rear end of the second body part 11b. The body parts 11a, 11b, 11f are arranged successively in axial direction of the body 3. Between the first body part 11a and the second body part 11b is a first axial connecting joint 12a and between the second body part 11b and the end body part 11f is a rear axial connecting joint 12e. At the axial connecting joint 12a axial connecting surfaces AC of the first body part 11a and 11b are pressed against each other by means of several fastening screws 13. At the rear axial connecting joint 12e connecting surfaces AC of the second body part 11b and the end body part 11f are pressed towards each other by means of fastening screws 13. At the rear axial connecting joint 12e there may be an intermediate element 14 between the body parts 11b and 11f. Inside the end body part 11f may be a pressure accumulator for storing pressurized fluid to an inner space of the body part. The rear end of the percussion piston 5 may be located inside the end body part 11f and the front end of the piston 5 may extend to an inner space of the first body part 11a.
[0054] As it is disclosed in FIG. 1, the fastening screws 13 are slanted relative to central axis D of the body 3. The fastening screw 13 may include a turning head 15 at one end of the screw and a thread end 16 at an opposite end. In FIG. 1 the fastenings screws 13 of both axial connecting joints 12a and 12e are oriented so that the turning heads 15 are facing towards the second end B, i.e. rear end of the breaking hammer 1. Further, longitudinal axis 17 of the fastening screws 13 are at the turning heads 15 at a greater transverse direction from the central axis D than at the thread end 16. The fastening screw 13 has a slanting angle S between the longitudinal axis 17 and normal line N of the axial connecting surface AC. FIG. 1 further shows that slanting angle of the fastening screws 13 of the axial connecting joints 12a and 12e may be slightly different.
[0055] The percussion piston 5 extends over the axial connecting joints 12a, 12e and moves in the axial direction relative to the axial connecting joints. Further, the first body part 11a may include one or more transverse connecting pins 19 for connecting the breaking tool 6 to the first body part 11a.
[0056] FIG. 2 discloses a breaking hammer 1 provided with a body 3, which includes six successively arranged body parts 11a-11f. Between the body parts are axial connection joints 12a-12e for connecting opposing axial connection surfaces AC of the body parts together. The axial connecting joints 12a-12e may include fastening screws 13a, 13b, which are slanted relative to the central axis D of the body 3. Turning heads 15 of first fastening screws 13a are facing towards the second end B of the body 3 and turning heads 15 of the second fastening screws 13b are facing towards the first end A of the body. Thus, the body 3 may include axial connecting joints having differently orientated slanted fastening screws 13a, 13b. In the first axial connection joint 12a it is further illustrated by means of a broken line 20, that there may be fastening screws having opposing orientation in one single axial connecting joint. Further, broken lines 21 indicate inner surfaces of the hollow body parts 11a-11f.
[0057] FIG. 3 discloses in more detailed the rear axial connecting joint 12e of the body 3 disclosed in FIG. 1. The end body part 11f may have a pressure space 22, and it may also serve as an end cover for the body 3. The end body part 11f includes a support flange 23 provided with screw holes 24 for the fastening screws 13. The support flange 23 further includes several recesses 25, which are located at the screw holes 24 and are dimensioned to receive turning heads 15 of fastening screws 13. Bottoms 26 of the recesses 25 are flat and they are orientated perpendicularly relative to the longitudinal axis 17 of the fastening screws 13. Thereby, the bottoms 26 are slanted so that they match with bottom surfaces of the turning heads 15 of the slanted fastening screws 13. The second body part 11b includes several threaded blind holes 27 for receiving the thread ends 16 of the fastening screws 13. Naturally, the blind holes 27 must have the same slanting direction as the fastening screws 13 and the screw holes 24. Further, the intermediate element 14 may be a substantially disc shaped piece and it may be provided with control surfaces 28 or edges on its inner surface side. The intermediate element 14 may also be provided with sealing elements, whereby axial connecting surfaces AC of the body parts 11b and 11f may be without any sealing means.
[0058] FIG. 4 discloses in more detailed the first axial connecting joint 12a of the body 3 disclosed in FIG. 1. The second body part 11b includes a support flange 29 provided with flat second support surfaces 31. The support flange 29 includes several screw holes 24 through which slanted fastening screws 13a are arranged. Turning heads 15 of the fastening screws 13a are located on the side of the second body part 11b and the first body part is provided with threaded blind holes 27. Longitudinal axis 17 of the fastening screws 13a are located at bottoms of the turning heads 15 at a first distance L1 from the central axis D of the body, and at the thread end 16 at a shorter second distance L2.
[0059] FIG. 5 discloses an alternative connecting joint 12 to the one disclosed in FIG. 4. The basic structure and features correspond to the axial connection joint 12a disclosed in FIG. 4. However, the support flange 29 is part of the first body part 11a and the turning heads 15 of the fastening screws 13b are on the first end A side of the body. Centers of bottoms of the turning heads 15 are located at a greater first distance L1 from the central axis D compared to the thread ends 16. In other words, the first distance L1 is examined at an intersection point between a bottom surface of the turning head 15 and a longitudinal axis 17 of the fastening screw 13, and the second distance L2 is examined at an intersection point between the longitudinal axis 17 and an outermost end of the fastening screw 13.
[0060] FIG. 6 discloses a support flange 29, which is located at a first end of a body part 11. The support flange includes an annular supplementary surface 30, which is slanted and is facing towards the second end of the body part 11. On an opposite side of the supplementary surface side is an annular connecting surface facing towards another body part. The annular supplementary surface 30 is provided with several flat second support surfaces 31 at screw holes 24. The flat second support surfaces 31 may extend from an outer circumference 32 of a body part 11 to an outer circumference 33 of the support flange 29. As can be noted, the surfaces 30 and 31 may alternate on the support flange 29. An alternative to the flat second support surfaces 31 is to form recesses 25 with flat bottoms at the screw holes 24, as it is disclosed above in this patent application. The screw holes 24 are located on a pitch diameter 34. Due to the slanted fastening screws, the pitch diameter 34 may be dimensioned to be relatively small compared to diameter of the outer circumference 32 of the body part 11. This way, diameter of an outer circumference 33 of the support flange 29 may be relatively small. In FIG. 6 the size of the support flange 29 is exaggerated in order to improve clarity. FIG. 6 further discloses that the body part 11 may include one or more axial fluid channels 35 between an inner circumference 36 and the outer circumference 32.
[0061] FIGS. 7 and 8 disclose a rectangular support flange 29 of a body part 11. The support flange 29 includes two flat support surface portions 31a and 31b, which have differing orientation. The support surfaces 31a and 31b are slanted relative to the central axis D of the body. A division line 36 is formed between the differently slanted surfaces 31a, 31b and it is located at the central axis D. FIG. 8 shows that the slanted support surface 31a matches with a bottom of a turning head 15 of a slanted fastening screw 13. Slanting angle of the surfaces 31a, 31b are selected in accordance with a slanting angle S of the fastening screw 13.
[0062] FIG. 9 further discloses a fastening screw 13 comprising a turning head 15 at a first end and threads 16 at a second end portion. At a bottom of the turning head 15 is a flat first support surface 40, which may be pressed against a flat second support surface as it is disclosed above.
[0063] Further, an alternative solution relates to a body of an impact unit having one or more connecting joints in a transverse direction to the longitudinal axis of the body. In other words, the connecting joint connects two body parts in another direction than in the axial direction of the body of the impact unit. This kind of connection joint may connect a body part of a pressure accumulator or a valve arrangement to the main body of the impact unit. The transverse connecting joint may have one or more slanted fastening screws in accordance to all the features disclosed in this patent application. This alternative solution is disclosed in FIG. 2, wherein the transversal body part 37, the transversal connecting joint 38 between the body 3 and the transversal element 37 is shown together with the transversal slanted fastening screws 39.
[0064] 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.
