Device and method for generating percussive pulses or vibrations for a construction machine

Abstract

A device and a method for generating percussive pulses or vibrations for a construction machine, in which a piston is reversibly reciprocated in a working space in a housing between a first reversal point and a second reversal point, wherein, for the purpose of generating the percussive pulses or vibrations, the piston is set into a reversible movement by a pressure fluid and the pressure fluid is led into and out of the working space in the region of the first reversal point and the second reversal point. The position of the piston is detected by way of a sensor, in that depending on the detected position of the piston a control unit controls at least one controllable valve, through which pressure fluid is led into and/or out of the working space, wherein by the control unit the movement of the piston is controlled.

Claims

1. A device for generating percussive pulses or vibrations for a construction machine, the device comprising: a housing, a piston which is reversibly reciprocated in a working space in the housing between a first reversal point and a second reversal point, and a pressure fluid supply, through which pressure fluid is able to be led into and out of the working space in a region of the working space on a side of the first reversal point and in a region of the working space on a side of the second reversal point, wherein the piston is able to be set into the reversible movement in order to generate the percussive pulses or vibrations, wherein a sensor having a bar-shaped first measuring component and a ring-shaped magnet as a second measuring component, and configured to determine a position of the piston in the working space is provided, at least one controllable valve is arranged, through which the pressure fluid is able to be led into and/or out of the working space, a control unit is provided which is connected to the sensor and the at least one controllable valve, wherein the control unit is configured to control and change the movement of the piston in the working space, the ring-shaped magnet is fixed at the piston and is arranged in a free space within the piston, at the housing the bar-shaped first measuring component of the sensor is firmly arranged, the first measuring component extending into the working space and into the free space in the piston, and the piston with the ring-shaped magnet slides contact-free along the bar-shaped first measuring component.

2. The device according to claim 1, wherein the valve is an electromagnetic valve.

3. The device according to claim 1, wherein the sensor has a linear sensor.

4. The device according to claim 1, wherein the piston is configured to strike onto a percussion surface which is arranged on at least one reversal point in order to generate a percussive pulse.

5. The device according to claim 1, wherein the control unit is configured to set and adjust a frequency and/or a stroke of the piston.

6. The device according to claim 1, wherein the control unit has a program memory configured to store different control programs for controlling the piston.

7. A construction machine, comprising: the device for generating percussive pulses or vibrations according to claim 1.

8. The construction machine according to claim 7, wherein the construction machine is an earth drilling apparatus.

9. The construction machine according to claim 7, wherein the construction machine is one of a pile driver and a vibrator.

10. A method for generating percussive pulses or vibrations for a construction machine with the device according to claim 1, in which the piston is reversibly reciprocated in the working space in the housing between the first reversal point and the second reversal point, wherein, for the purpose of generating the percussive pulses or vibrations, the piston is set into the reversible movement by means of the pressure fluid and the said pressure fluid is led into and out of the working space in the region of the working space on the side of the first reversal point and in the region of the working space on the side of the second reversal point, wherein the position of the piston is detected by way of a sensor and depending on the detected position of the piston the control unit controls the at least one controllable valve, through which the pressure fluid is led into and/or out of the working space, wherein by the control unit the movement of the piston is controlled.

Description

(1) The invention will be described below by reference to a preferred embodiment, which is shown schematically in the attached drawing, in which:

(2) The FIGURE shows a schematic of a preferred embodiment of the present disclosure.

(3) In the single drawing a device 10 according to the invention is illustrated which is designed to generate percussive pulses. The device 10 has a housing 12 with a cylindrical working space 14, in which a piston 20 of approximately cylindrical shape is supported in a linearly movable manner such that it is reversible between two reversal points. The piston 20 is supported in a fluid-tight manner in the housing 12 and, as shown in the embodiment, can protrude with one side from the housing 12. With a free front face 24 the piston 20 strikes onto a corresponding percussion surface 18 which can be an insertion end of a drill drive shaft.

(4) In the region of the upper first reversal point a first opening 15 for a first supply line 31 of a pressure fluid supply 30 is provided on the housing 12. In the region of a lower second reversal point the working space 14 is connected through a second opening 16 to a second supply line 32 of the pressure fluid supply 30. By means of a controllable valve 36, which is designed as a 2/4 directional control valve in the illustrated embodiment, the two openings 15, 16 are alternately connected to a hydraulic pressure source P and an unpressurized disposal tank T. Through this, two opposite pressure chambers in the working space 14 are each alternately filled with pressure fluid and emptied of the pressure fluid. As a result, the piston 20 is set into a desired reversible movement in the housing 12.

(5) According to the invention a measuring means 40 with a first elongate measuring component 42 is provided on the housing 12. The first measuring component 42 is of bar-shaped design and extends into the working space 14 and into a free space 22 arranged correspondingly thereto in the piston 20. In the free space 22 in a lower region thereof a ring-shaped magnet is arranged as second measuring component 44. The second measuring component 44 is firmly connected to the movable piston 20 while the elongate first measuring component 42 is firmly attached to the housing 12. The measuring means 40 is designed e.g. as an inductive linear sensor which precisely ascertains the position of the second measuring component 44 and therefore of the piston 20 with respect to the elongate first measuring component 42 and thus the position of the piston 20 in the working space 14.

(6) Via a line connection 52 the measuring means 40 is connected to a control unit 50, whereby analog signals or digital data on the current position of the piston 20 in the working space 14 are transmitted. Depending on a predetermined program or control logic of the control unit 50 the controllable valve 36 is actuated via electromagnetic elements 37 so that e.g. the first supply line 31 is connected to the unpressurized tank T and the second supply line 32 to the pressure source P, as illustrated in the drawing. When the valve 36 is switched over by the control unit 50 the pressure source P can then be connected to the first supply line 31 while the tank T is connected to the second supply line 32. In this valve position the lower region of the working space 14 is emptied of pressure fluid while an upper region of the working space 14 is at the same time filled with pressure fluid, in which case the piston 20 then moves from the upper first reversal point downwards to the lower second reversal point. When the measuring means 40 establishes that a trigger point of the piston 20 has been reached in the housing 12, a switch-over of the valve 36 can then be effected again by the control unit 50 so that a change of direction is brought about by actuating the electromagnetic elements 37 of the controllable valve 36 via the control lines 54.

(7) Through a corresponding change of the control logic in the control unit 50 the frequency of the piston 20 and the stroke of the piston 20 between the two reversal points can be changed and set without further ado.