SPRING HAMMER FOR RAPPING A SURFACE

Abstract

A spring hammer for rapping a surface, the spring hammer includes an anvil with an impact surface. The anvil can fastened to the surface to be rapped. A movable piston has a first end that is in operation moved towards the impact surface of the anvil. A guiding structure guides the piston to move in a defined direction with respect the anvil and a device for launching the piston to move the piston towards the impact surface of the anvil. The piston is a solid block in which the first end of the piston is machined to an integrated flexible spring geometry.

Claims

1. A spring hammer for rapping a surface, the spring hammer comprising: an anvil with an impact surface, which anvil can be fastened to the surface to be rapped; a movable piston having a first end that is in operation moved towards the impact surface of the anvil; a guiding structure for guiding the piston to move in a defined direction with respect to the anvil; and a device for launching the piston to move the piston towards the impact surface of the anvil, wherein the first end of the piston or the impact surface of the anvil is machined to form an integrated flexible spring geometry.

2. A spring hammer in accordance with claim 1, wherein the spring coefficient of the flexible spring geometry such that the maximum deceleration of the piston is on the order five hundred grams to one thousand grams.

3. A spring hammer in accordance with claim 2, wherein the flexible spring geometry comprises a curved hollow part integrated to an end of a solid block part of the piston.

4. A spring hammer in accordance with claim 2, wherein the flexible spring geometry comprises a curved hollow part integrated to a solid portion of the anvil.

5. A spring hammer in accordance with claim 3, wherein the curved hollow part has an open free end.

6. A spring hammer in accordance with claim 1, wherein the flexible spring geometry is made of high quality tempering steel material.

7. A spring hammer in accordance with claim 1, wherein the device for launching the piston comprises a spring.

8. A spring hammer in accordance with claim 7, wherein the spring is a compression spring.

9. A spring hammer in accordance with claim 7, wherein the spring is an extension spring.

10. A spring hammer in accordance with claim 9, further comprising at least two extension springs, arranged outside the guiding structure.

11. A spring hammer in accordance with claim 7, further comprising a tensioner for tensioning the spring.

12. A spring hammer in accordance with claim 11, wherein the tensioner for tensioning the spring comprises a pneumatic tensioning device.

13. A piston for a spring hammer, the spring hammer comprising: an anvil with an impact surface, which anvil can be fastened to the surface to be rapped, a movable piston having a first end that is in operation moved towards the impact surface of the anvil; a guiding structure for guiding the piston to move in a defined direction with respect to the anvil; and a device for launching the piston to move the piston towards the impact surface of the anvil, wherein the first end of the piston or the impact surface of the anvil is machined to form an integrated flexible spring geometry, and wherein the first end of the piston is machined to form an integrated flexible spring geometry.

14. An anvil piece for a spring hammer, the spring hammer comprising: an anvil with an impact surface, which anvil can be fastened to the surface to be rapped, a movable piston having a first end that is in operation moved towards the impact surface of the anvil; a guiding structure for guiding the piston to move in a defined direction with respect to the anvil; and a device for launching the piston to move the piston towards the impact surface of the anvil, wherein the first end of the piston or the impact surface of the anvil is machined to form an integrated flexible spring geometry, and wherein the impact surface of the anvil piece is machined to form an integrated flexible spring geometry.

15. A spring hammer in accordance with claim 13, wherein the spring coefficient of the flexible spring geometry such that the maximum deceleration of the piston is on the order five hundred grams to one thousand grams.

16. A spring hammer in accordance with claim 15, wherein the flexible spring geometry comprises a curved hollow part integrated to an end of a solid block part of the piston.

17. A spring hammer in accordance with claim 15, wherein the flexible spring geometry comprises a curved hollow part integrated to a solid portion of the anvil.

18. A spring hammer in accordance with claim 16, wherein the curved hollow part has an open free end.

19. A spring hammer in accordance with claim 13, wherein the flexible spring geometry is made of high quality tempering steel material.

20. A spring hammer in accordance with claim 13, wherein the device for launching the piston comprises a spring.

21. A spring hammer in accordance with claim 20, wherein the spring is a compression spring.

22. A spring hammer in accordance with claim 20, wherein the spring is an extension spring.

23. A spring hammer in accordance with claim 22, further comprising at least two extension springs, arranged outside the guiding structure.

24. A spring hammer in accordance with claim 20, further comprising a tensioner for tensioning the spring.

25. A spring hammer in accordance with claim 24, wherein the tensioner for tensioning the spring comprises a pneumatic tensioning device.

26. A spring hammer in accordance with claim 14, wherein the spring coefficient of the flexible spring geometry such that the maximum deceleration of the piston is on the order five hundred grams to one thousand grams.

27. A spring hammer in accordance with claim 26, wherein the flexible spring geometry comprises a curved hollow part integrated to an end of a solid block part of the piston.

28. A spring hammer in accordance with claim 26, wherein the flexible spring geometry comprises a curved hollow part integrated to a solid portion of the anvil.

29. A spring hammer in accordance with claim 27, wherein the curved hollow part has an open free end.

30. A spring hammer in accordance with claim 14, wherein the flexible spring geometry is made of high quality tempering steel material.

31. A spring hammer in accordance with claim 14, wherein the device for launching the piston comprises a spring.

32. A spring hammer in accordance with claim 31, wherein the spring is a compression spring.

33. A spring hammer in accordance with claim 31, wherein the spring is an extension spring.

34. A spring hammer in accordance with claim 32, further comprising at least two extension springs, arranged outside the guiding structure.

35. A spring hammer in accordance with claim 31, further comprising a tensioner for tensioning the spring.

36. A spring hammer in accordance with claim 35, wherein the tensioner for tensioning the spring comprises a pneumatic tensioning device.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The invention is described below with reference to the accompanying drawings, in which

[0022] FIGS. 1 to 3 schematically illustrate cross sections of different spring hammers in accordance with the present invention.

[0023] FIG. 1 illustrates a spring hammer 10 in accordance with a preferred embodiment of the present invention. The spring hammer comprises an anvil 12 with an impact surface 14 at one end of the anvil. The other end of the anvil is attached by means of a welded seam 16 to a hammering beam 18. If the wall to be rapped is, for example, an outer wall of a reactor, channel or funnel, the other end of the hammering beam 18, which is not seen in FIG. 1, may be welded to the wall. Alternatively, in such a case, a separate hammering beam 18 may not be necessary, but the anvil 12 may be attached directly to the wall to be rapped. If, in turn, there are, for example, heat exchange tube banks in a gastight space of a reactor or a steam boiler are to be rapped, the hammering beam 18 may be flexibly sealed to the wall of the gas space and welded to the heat exchange tubes or their connecting piece. Since the different sealing and attaching methods of the hammering beam are of a known technique, they will not be described below in detail.

[0024] The spring hammer comprises a movable piston 20 having a first end 22 with a flexible spring geometry. The flexible spring geometry advantageously comprises a curved hollow part with an open free end, integrated to a solid portion of the anvil. The first end is in operation moved towards the impact surface 14 of the anvil.

[0025] Material of the piston is advantageously high quality tempering steel to suit for spring use and the required machining. However, a large range of materials can be suitable, as long as they tolerate the reasonable cyclic tensile and compressive loads, and are easy enough to machine properly.

[0026] The spring hammer also comprises a cylindrical vessel 24 acting as a guiding structure that allows the piston 20 to move only in a defined direction with respect to the anvil. The cylindrical vessel is attached to the anvil 12, for example, by bolts 26. The bolts are mounted in place by using suitable flexible elements, such as flexible bushings 27, to dampen the effect of the hits to the guiding structure. The bolts 26 are herein arranged perpendicular to the hammering direction, but they could alternatively be arranged through a suitable flange, as is clear to a person skilled in the art of connecting pieces, in the direction of or opposite to the hammering direction. In such cases, the flexible elements are advantageously springs, such as suitable disc springs.

[0027] The second end of the piston 20, opposite to the first end of the piston, is attached to an end plate 28. The end plate 28 is arranged outside an outer end 29 of the cylindrical vessel 24. Multiple extension springs 30, such as four extension springs, are arranged between a flange 32 in the cylindrical vessel 24 and the end plate 26.

[0028] The spring hammer 10 in FIG. 1 is illustrated in an impact position, in other words, in a position, in which the springs 30 are in their minimum length and the first end 22 with a flexible spring geometry of the piston 20 is in contact with the anvil 12. When using the spring hammer, the springs 30 are tensioned by drawing the piston 20 outwards by a suitable tensioning device. The tensioning device, not shown in FIG. 1, is usually pneumatic, but it may alternatively be, for example, electromagnetic or be, based on using a separately supported motor. Thus, in operation, the piston 20 is first excited by moving the piston further from the anvil, after which, the springs 30 are released so as to launch the piston to move towards the impact surface 14 of the anvil. When the springs 30 are tensioned to a desired tension, the impact is caused by releasing the springs whereby the first end 22 of the piston 20 hits at a high speed to the impact surface 14 of the anvil 12. Since the direction of the hammer movement of the hammer 18 is defined by the guiding means, i.e., the cylindrical vessel 24, the impact is always appropriately directed relative to the anvil.

[0029] The flexible spring geometry at the first end 22 of a movable piston 20 has advantageously a high spring constant so as to dampen the stopping of the piston 20. The flexible spring geometry extends the duration of a single impact without substantially diminishing the total amount of the hammering energy. According to an exemplary solution, the deceleration of the hammer movement is, preferably, at most on the order of one thousand grams.

[0030] The strokelength, in other words, the change in the length of the spring to be utilized when using the apparatus, is preferably fifty millimeters to one hundred millimeters, such as sixty mm. According to a preferred embodiment, the mass of the hammer is about forty kg, the spring force at maximum tension about one thousand Newtons and at the end of the impact still about five hundred Newtons. Thereby the initial acceleration of the impact is twenty-five m/s.sup.2 and the impact energy one hundred twelve Nm. By adjusting the strokelength of the spring hammer, it is naturally possible to adjust the strength of the impact. The advantageous values of the parameters of the spring hammer depend on the application when the spring hammer is used, so they may deviate a lot from the exemplary values described above.

[0031] In FIG. 2, which illustrates another preferred embodiment of the spring hammer in accordance with the invention, the parts corresponding to those illustrated in FIG. 1 are disclosed with the same reference numbers as in FIG. 1.

[0032] FIG. 2 illustrates a spring hammer 10′ in accordance with a second preferred embodiment of the present invention. The spring hammer 10′ differs from spring hammer 10 shown in FIG. 1 mainly in that the extension springs 30 are replaced by a compression spring 30′ that is arranged between a second end 34 of the piston and the end plate 26. Thus, the spring 30′ is tensioned by compressing it by suitable means, such as pneumatically, towards the end plate 26. Otherwise, the operation of the spring hammer 10′ corresponds to that of spring hammer 10 shown in FIG. 1.

[0033] FIG. 3 illustrates a spring hammer 10″ in accordance with a third preferred embodiment of the present invention. The spring hammer 10″ differs from spring hammer 10 shown in FIG. 1 in that a flexible spring geometry 22 is arranged at the impact surface 14′ of the anvil instead of the first end of the piston 20. Thus, the flexible spring geometry is not moving with the piston, but it stays with the anvil, i.e., it is not movable in the operation of the spring hammer. Such a flexible spring geometry, however, has the same effect to dampen the hits of the piston as the solutions described above. An anvil with a flexible spring geometry arranged at the impact surface 14′ of the anvil can naturally also be arranged to a spring hammer with a compression spring, as shown, for example, in FIG. 2.

[0034] According to a further aspect of the present invention, a piston with a first end machined to form an integrated flexible spring geometry, as shown in FIGS. 1 and 2, or an anvil with an impact surface machined to form an integrated flexible spring geometry, as shown in FIG. 3, can be a separate product, for example, a spare part to an existing spring hammer.

[0035] The present invention is described above with reference to an exemplary embodiment, but the invention also comprises many other embodiments and modifications. It is thus evident that the disclosed exemplary embodiment is not intended to restrict the scope of invention, but the invention comprises a number of other embodiments that are limited by the accompanying claims and the definitions therein alone.