VIBRATION GENERATOR

Abstract

The invention relates to a vibration generator having at least one shaft which can be driven in a rotating manner and on which at least one unbalanced unit is arranged that is constructed of at least two weight elements, of which a first weight element is firmly mounted on the shaft and a second weight element is supported in a radially adjustable manner which, depending on the speed of rotation of the shaft, is adjustable between a radially internal first position and a radially external second position. According to the invention a locking means is provided, through which the adjustable second weight element is secured in the first position up to a predetermined triggering speed of rotation of the shaft and, on reaching the triggering speed of rotation, is released and adjustable.

Claims

1. Vibration generator, having at least one shaft which can be driven in a rotating manner and on which at least one unbalanced unit is arranged that is constructed of at least two weight elements, of which a first weight element is firmly mounted on the shaft and a second weight element is supported in a radially adjustable manner which, depending on the speed of rotation of the shaft, is adjustable between a radially internal first position and a radially external second position, wherein a locking means is provided, through which the adjustable second weight element is secured in the first position up to a predetermined triggering speed of rotation of the shaft and, on reaching the triggering speed of rotation, is released and adjustable.

2. Vibration generator according to claim 1, wherein the second weight element is supported in a displaceable manner along at least one linear guide which is directed transversely to an axis of rotation of the shaft.

3. Vibration generator according to claim 1, wherein the locking means has at least one locking element which is adjustable between a locking position and a release position.

4. Vibration generator according to claim 3, wherein the at least one locking element is adjustable transversely to the linear guide of the second weight element.

5. Vibration generator according to claim 3, wherein the at least one locking element is held in a spring-tensioned manner in the locking position and engages in a locking recess on the adjustable second weight element.

6. Vibration generator according to claim 5, wherein the locking recess has a run-in and/or run-out slope.

7. Vibration generator according to claim 3, wherein two locking elements are provided which are directed and displaceable in opposite directions.

8. Vibration generator according to claim 1, wherein at least one resetting spring is provided, through which the second weight element can be reset into the radially internal first position.

9. Vibration generator according to claim 1, wherein the unbalance of the unbalanced unit is reduced by adjusting the second weight element into the radially external second position.

10. Vibration generator according to claim 1, wherein the unbalance of the unbalanced unit is increased by adjusting the second weight element into the radially external second position.

11. Vibratory pile driver having a carrier, on which a vibration generator is supported in a vertically adjustable manner, wherein a vibration generator according to claim 1 is provided.

12. Drilling apparatus having a drill drive, by which a drill rod can be driven in a rotating manner, wherein a vibration generator according to claim 1 is provided.

Description

[0021] The invention is explained in the following by way of a preferred embodiment illustrated schematically in the drawings, wherein show:

[0022] FIG. 1 a schematic illustration of a vibration generator according to the invention;

[0023] FIG. 2 a cross-sectional view of an unbalanced unit of a vibration generator according to the invention, in which an adjustable weight element is located in a radially internal first position; and

[0024] FIG. 3 a cross-sectional view of the unbalanced unit according to FIG. 2, with the second weight element being located in a radially external second position.

[0025] In FIG. 1 the construction of a vibration generator 10 according to the invention with two pairs of unbalanced units 20 is shown in a strongly schematic manner. A first pair of unbalanced units 20 is driven in a rotating manner by a first drive 14 which is designed as a hydraulic motor. By way of gear wheels, not shown, the two unbalanced units 20 of the first pair are connected to each other in a rotating manner, with a first unbalance 20 being driven clockwise in a rotating manner in the direction of rotation D1 and a second unbalanced unit 20 being driven in a rotating manner in the opposite direction of rotation D2. Due to this arrangement the unbalances of both unbalanced units 20 of a pair of unbalances can add up in the vertical direction while compensating each other in the horizontal direction. Accordingly, a second pair of unbalanced units 20 is arranged and driven in a rotating manner by a second drive 14 which is also a hydraulic motor. The two pairs of unbalanced units 20 are coupled via a phase adjusting means 18 which is only indicated schematically and through which an angle of rotation of both pairs of unbalanced units 20 can be adjusted with respect to each other.

[0026] The construction of the unbalanced units 20 according to the invention is illustrated and explained in greater detail in conjunction with FIGS. 2 and 3. To form an unbalanced unit 20 on a shaft 12, which is driven in a rotating manner about an axis of rotation 13, a first weight element 22 is arranged on the shaft 12 asymmetrically thereto. Due to the asymmetrical arrangement of the first weight element 22 an unbalance is generated when the unbalanced unit 20 is driven in a rotating manner. To reduce the amount of unbalance a second weight element 24 is supported in an adjustable manner relative to the shaft 12 and the first weight element 22. The second weight element 24 has two parallel directed guide bores 25, with which the second weight element 24 is positioned in a displaceable manner onto two bolt-shaped linear guides 26 directed transversely to the shaft 12 on the first weight element 22. The linear guides 26 each project into an open cylindrical receiving space 27 designed on the second weight element 24. In the receiving space 27 a resetting spring 28 is arranged in each case which is supported on the one hand on a base of the receiving space 27 of the second weight element 24 and on the other hand on a support ring 23. The support ring 23 is respectively arranged at a free end of the bolt-shaped linear guide 26 and is fixed by a screw-nut-like fastening element.

[0027] On the first weight element 22 a locking means 30 with two pin-shaped locking elements 32 is arranged in a receiving bore. At their free end the pin-shaped locking elements 32 have a rounded head 36. The locking elements 32 directed transversely to the shaft 12 are tensioned in the outward direction by a tension spring 34. The tension springs 34 are each supported in the inward direction by a center piece 31. Through the tension springs 34 the two locking elements 32 are pressed with their respective head 36 into a locking recess 40 which is of approximately triangular shape in cross section and designed on the adjacent adjustable second weight element 24. Through this, the second weight element 24 is locked in a radially internal first position according to FIG. 2.

[0028] With an increasing speed of rotation of the shaft 12 a centrifugal force exerted on the second weight element 24 rises. When a triggering speed of rotation has been reached the locking pins 32 are pressed contrary to the tensioning force of the tension spring 34 by a wedge-shaped run-in slope 42 and a wedge-shaped run-out slope 44 on the locking recess 40 back into the receiving bore of the first weight element 22. As a result, the second weight element 24 is then released and adjustable in the radial direction. Due to the applied centrifugal force the second weight element 24 can assume a radially external second position which is shown in FIG. 3. In this radially external second position the weight of the second weight element 24 is displaced radially outwards in such a manner that the asymmetrical weight distribution of the first weight element 22 is compensated partially and thus the unbalance is reduced.

[0029] During radial outward displacement the resetting spring 28 is compressed and tensioned. Hence, when the speed of rotation of the shaft 12 is reduced the second weight element 24 can be pressed back into the radially internal first position according to FIG. 2. On reaching the first starting position the pin-shaped locking elements 32 are once again pressed by the respective tension springs 34 in the outward direction into the opposite locking recesses 40 on the second weight element 24.