VIBRATORY HAMMER WITH ELECTRIC MOTOR

Abstract

Abstract: A vibratory hammer (1) for driving or retracting sheet piles, pipes or other elements into or from the soil, comprises a vibration case (2). A clamp (17) is attached to the vibration case (2). The clamp (17) comprises gripping jaws (18) for gripping the sheet piles or other elements. A yoke (3) is connected to the vibration case (2) via one or more vibration damping elements for suspending the vibratory hammer (1) from a hoist cable or the like. In the vibration case (2) an even number of pairwise arranged eccenter weights are rotationally mounted. The vibratory hammer comprises at least one synchronous electric motor (13A) for driving the rotation of the eccenter weights.

Claims

1.-14. (canceled)

15. A vibratory hammer for driving or retracting sheet piles, pipes or other elements into or from the soil, said vibratory hammer comprising: a vibration case; an even number of pairwise arranged eccenter weights, which are rotationally mounted in the vibration case; at least one synchronous electric motor as a drive motor for driving the rotation of the eccenter weights; a clamp attached to the vibration case, said clamp comprising gripping jaws for gripping the sheet piles, pipes or other elements; and a yoke for suspending the vibratory hammer from a hoist cable or the like, said yoke being connected to the vibration case via one or more vibration damping elements.

16. The vibratory hammer according to claim 15, wherein the at least one synchronous electric motor is a permanent-magnet synchronous motor (PMSM).

17. The vibratory hammer according to claim 15, wherein the at least one synchronous electric motor is attached to the vibration case.

18. The vibratory hammer according to claim 17, wherein the at least one synchronous electric motor is attached to the vibration case on the outer side of the vibration case.

19. The vibratory hammer according to claim 16, wherein the at least one synchronous electric motor is integrated in an eccenter shaft, wherein stator windings are located inside the eccenter shaft and permanent magnets are arranged around the stator windings inside the eccenter shaft of the eccenter weight.

20. The vibratory hammer according to claim 15, wherein the vibratory hammer comprises four eccenter weights arranged in two pairs one above the other.

21. The vibratory hammer according to claim 15, wherein the eccenter weights of one pair are synchronized by one or more gears.

22. The vibratory hammer according to claim 15, wherein different pairs of eccenter weights are synchronized by one or more gears.

23. The vibratory hammer according to claim 15, wherein each of the eccenter weights is directly driven by one of said at least one synchronous electric motors.

24. The vibratory hammer according to claim 15, wherein each pair of eccenter weights is driven by one of said at least one synchronous electric motors.

25. The vibratory hammer according to claim 15, wherein a frequency drive or an inverter, associated with each individual synchronous electric motor of the at least one synchronous electrical motor, is mounted on the vibratory hammer.

26. The vibratory hammer according to claim 25, wherein the frequency drive and/or inverter is integrated in the at least one synchronous electric motor.

27. The vibratory hammer according to claim 25, wherein an electronic control system is provided which is connected with the frequency drive or inverter of each of the at least one synchronous electric motor so as to control the at least one synchronous electric motor.

28. The vibratory hammer according to claim 27, wherein the control system is configured to electronically control the phase angle between the eccenter weights or pairs of eccenter weights.

29. The vibratory hammer according to claim 27, wherein the control system is configured to provide a proportional control of centrifugal force and speed.

30. The vibratory hammer according to claim 29, wherein the control system is configured to operate at a constant centrifugal force but with a proportional speed and thus vibration frequency.

Description

[0032] The invention will be further described in the following detailed description of a possible embodiment with reference to the drawing, in which:

[0033] FIG. 1 shows a front elevational view of a vibratory hammer according to the invention,

[0034] FIG. 2 shows a side elevational view of the vibratory hammer of FIG. 1,

[0035] FIG. 3 illustrates a cross section through the line A-A indicated in FIG. 2,

[0036] FIG. 4 illustrates a cross section through the line B-B indicated in FIG. 1,

[0037] FIG. 5 shows a front elevational view of another vibratory hammer according to the invention,

[0038] FIG. 6 shows a side elevational view of the vibratory hammer of FIG. 5,

[0039] FIG. 7 illustrates a cross section through the line B-B indicated in FIG. 6, and

[0040] FIG. 8 illustrates a cross section through the line A-A indicated in FIG. 5.

[0041] In the FIGS. 1-4 a vibratory hammer 1 is schematically illustrated. The vibratory hammer 1 comprises a vibration case 2 and a yoke 3.

[0042] The yoke 3 is a part designed to suspend the vibratory hammer 1 from a crane, a rig or similar equipment. It comprises a member which can cooperate with a crane hook or the like to attach it to a hoisting cable. The yoke 3 in this specific embodiment comprises an outer housing 4 which includes the hook means 7 to cooperate with a hoisting hook of a crane or rig. The yoke 3 furthermore comprises an inner part 5 which is rigidly attached to the vibration case 2. The inner part 5 is received in the outer housing 4 and connected thereto via multiple vibration absorbing elements 6 for example made of an elastomer material. The vibration absorbing elements 6 prevent that vibrations generated in the vibration box 2 by operating the vibratory hammer 1, are transferred to the equipment from which the vibratory hammer 1 is suspended.

[0043] In the vibration box 2 two pairs of rotational eccenter weights are arranged, the eccenter weights of one pair being indicated by reference numeral 8A, and the eccenter weight of the other pair being indicated by reference numeral 8B. The eccenter weights 8A and 8B are each arranged on an eccenter shaft 9A and 9B, respectively. The eccenter shafts 9A, 9B are mounted in the vibration case 2 with bearings 10. Gears 11A an 11B are mounted on the eccenter shafts 9A and 9B, respectively (cf. FIG. 3). The gears 11A of the eccenter shafts 9A of an upper pair of eccenter weights 8A mesh with each other whereby the two eccenter weights 8A of the upper pair are synchronised with each other. Similarly, the gears 11B of the eccenter shafts 9B of a lower pair of eccenter weights 8B mesh with each other whereby the two eccenter weights 8B of the lower pair are synchronised with each other.

[0044] In a region of the vibration case 2 next to the pairs of eccenter weights two permanent magnet synchronous motors (PMSM) 13A and 13B are mounted to the outer side of the vibration case 2. In particular the motor 13A is arranged on the front side of the vibration case 2. The other motor 13B is arranged on the or back side of the vibration case 2. The PMSM's 13A, 13B each have a motor shaft which is connected to a respective drive shaft 12A, 12B, which is rotationally mounted in the vibration case 2. A gear wheel 14A is mounted on the drive shaft 12A. A gear wheel 14B is mounted on the drive shaft 12B. The gear wheel 14A meshes with one of the gear wheels 11A, the gear wheel 14B meshes with one of the gear wheels 11B. Thus the motor 13A is arranged to drive the upper pair of eccenter weights 8A and the other motor 13B is arranged to drive the lower pair of eccenter weights 8B.

[0045] On the other side of the pairs of eccenter weights 8B a synchronisation shaft 15 is mounted in the vibration case 2. Two gears 16A and 16B are mounted on the synchronisation shaft 15. The gear 16A meshes with one of the gear wheels 11A and the gear 16B meshes with one of the gear wheels 11B. Thus, via the synchronistaion shaft 15 the rotation of the upper pair of eccenter weights 8A is synchronised with the rotation of the lower pair of eccenter weights 8B. The gears 11A of the eccenter shafts 9A of an upper pair of eccenter weights 8A mesh with each other whereby the two eccenter weights 8A of the upper pair are synchronised with each other. During the start-up or shut down stages the rotation frequencies decrease and resonance may occur which may cause damage to the environment such as buildings nearby. The synchronisation shaft 15 may have an adjustment mechanism which allows to adjust the phase angle between the upper pair and lower pair of eccenter weights during the start-up and the shut down stage of the vibratory hammer 1, whereby the resonance of the environment can be avoided.

[0046] At a lower side of the vibration case 2 a clamp 17 is attached to the vibration case 2. The clamp 17 comprises jaws to grip an upper side of a sheet pile or another object to be driven into the soil or to be retracted from the soil. The vibrations caused by the rotating eccenter weights are transferred from the vibration case 2 through the clamp 17 into the sheet pile or other object, which thereby vibrates and loosens the soil in which it is driven or from which it is retracted.

[0047] Another possible embodiment of a vibration hammer 21 is shown in FIGS. 5-8. In this embodiment like parts are indicated by the same reference numerals as in the FIGS. 1-4 and for a description of those parts reference is made to the foregoing description. This embodiment has four permanent magnet synchronous motors 23 which are mounted to the outside of the vibration case 2 in line with the eccenter shafts 9A, 9B. In this embodiment the respective motor shafts of the synchronous motors 23 extend are directly coupled to the eccenter shafts 9A, 9B. The synchronisation between the eccenter weights 8A, 8B is done electronically via a controller that controls the synchronous motors 23. The controller may also be configured to take care of the adjustment of the phase angle between the upper and lower pair of eccenters 8A, 8B during the start-up and shut down stage of the vibratory hammer 21.

[0048] In another possible embodiment, which is a sort of hybrid between the embodiments of FIGS. 1-4 and of FIGS. 5-8, the eccenter weights 8A or 8B of one pair are driven by one motor and are coupled and thus synchronised by gears as is shown in FIG. 3. The phase angle between the pairs can be electronically controlled by the controller instead of using the synchronisation shaft 15, which is thus omitted in such an embodiment.

[0049] A frequency drive or an inverter associated with each individual synchronous electric motor 13A, 13B, 23 may be mounted on the vibratory hammer 1, 21 for example on the yoke or on the vibration case. It may also be possible to integrate the frequency drive and inverter in the motor. A higher level control system, which is not located on the vibratory hammer may be connected by wires or wireless with the frequency drive and inverter and may be used to control the speed and synchronisation of the motors 13A, 13B, 23.