ROTARY DRIVER FOR A HELICAL PILE FOUNDATION ATTACHED TO A BOOM ARM OF AN EXCAVATOR FORMING A COUNTER-SUPPORT
A rotary driver 1 for a helical pile foundation 2 attached to a boom arm 3 of an excavator 5 forming a counter-support is described by means of which the helical pile foundation 2 can be screwed into or out of the ground in a defined direction. The rotary driver 1 is supplied by the excavator 5 with appropriate power, preferably hydraulic power, and is arranged at the front end of the boom arm 3 of the excavator 5. A rotary drive 6 is provided for this purpose at the front end of the boom arm 3 which transmits a drive torque 11 to the helical pile foundation 2, for which purpose a chucking device 7 for the helical pile foundation 2 is provided at the end of the rotary drive 6 facing toward the helical pile foundation 2. An additional counter-support 4 is arranged on the rotary drive 6, on the front end of the boom arm 3, or on the chucking device 7 and is anchored in the ground at the end opposite the area of arrangement. The additional counter-support 4 at least partially compensates for the forces acting on the helical pile foundation laterally to the plane of extension of the boom arm 3 due to the drive torque 11.
The invention relates to a rotary driver for a helical pile foundation that is attached to a boom arm of an excavator forming a counter-support. The helical pile foundation is screwed into or out of the ground using the rotary driver. Power for driving the turning device is provided by the excavator.
Rotary drivers of this type which are attached to an excavator arm and by means of which helical pile foundations can be screwed into the ground or screwed out again from the same are known. U.S. Pat. No. 4,199,033 describes a rotary device that is attached to an excavator arm and is capable of driving a helical pile foundation into the ground. The rotary device is fastened to the excavator arm in the form of a hydraulic drive unit on whose lower, groundward-facing side is arranged a chucking device for the helical pile foundation. The helical pile foundation is driven around its longitudinal axis by means of a rotary device. Corresponding pivot axes make it possible for the helical pile foundation to be pivoted in any direction that deviates from a vertical insertion direction and to be screwed into the soil in a desired direction or screwed out again from the same.
In the known device, the excavator arm is attached to the upper part of the rotary driver. When a large deflection of the excavator arm occurs, a relatively large tilting moment can occur when screwing in the helical pile foundation, so that the helical pile foundation can wobble or tilt while it is being screwed in. This makes it difficult to screw in the helical pile foundation at a desired, defined angle, which is disadvantageous. If there is an axial offset between the load application point and the screw axis, a feed force creates a skewing moment when the excavator boom arm is pushed down. This skewing moment causes the helical pile foundation that is to be screwed in to deviate from the desired installation direction. During the installation process, the excavator operator can counteract this by attempting to compensate for the degree of skewing. The drawback here is that the installation process is highly dependent on the skill of the excavator operator. When the helical pile foundation is being screwed in using the rotary driver attached to the excavator arm, a torque is exerted on the helical pile foundation, whereby transverse forces are produced which act on the helical pile foundation. In addition, forces arise in the longitudinal direction of the excavator forming a counter-support. The forces exerted on the helical pile foundation as a result, including the torque from the rotary driver, result in a disadvantageous deviation from the desired screw-in angle of the helical pile foundation in the ground during the installation process.
It is the object of the invention, in contrast to the known rotary driver for a helical pile foundation attached to a boom arm of an excavator forming a counter-support, is for at least a portion of the acting transverse forces and the skewing moment to be compensated for when there is an axial offset, thus enabling the excavator operator to better control the vertical alignment of the helical pile foundation using the available articulation forces.
This object is achieved with a rotary driver for a helical pile foundation which is attached to a boom arm of an excavator forming a counter-support and has the features according to claim 1. Expedient refinements are defined in the dependent claims.
According to the invention, a helical pile foundation is screwed into or out of the ground or soil by means of a rotary driver that is attached to a boom arm of an excavator forming a counter-support. The rotary driver has a rotary drive and a chucking device for the helical pile foundation, the rotary drive being supplied with power from the excavator, being arranged at the front end of the boom arm, and transmitting a drive torque to the helical pile foundation for the purpose of screwing into or out of the ground via the chucking device. The excavator itself forms a counter-support for the installation process, which, depending on the size of the excavator, can often no longer fully compensate for the transverse force resulting from the driving torque.
According to the invention, an additional counter-support is therefore provided which acts on the rotary drive, on the front end of the boom arm of the excavator, or on the chucking device for the helical pile foundation and is anchored in the ground. The additional counter-support is designed so as to compensate for the forces acting on the helical pile foundation laterally to the plane of extension of the boom arm of the excavator due to the drive torque. Such an additional counter-support is easy to anchor in the ground—e.g., in the manner of a peg as when anchoring a tent—and likewise easy to fasten to the front end of the boom arm or to the chucking device or to the outer, preferably cylindrical housing of the rotary drive of the rotary driver. This additional counter-support absorbs at least a portion of the forces that arise from the lateral forces and from the skewing moment when there is an axial offset. This enables the excavator operator to better control the vertical alignment of the helical pile foundation while screwing it in. The additional counter-support can also be another vehicle, particularly another excavator, in which case the anchoring in the ground is achieved by means of the drive chains.
The additional counter-support is preferably embodied as a tension cable or a tension chain. The tension cable is attached to the side of the helical pile foundation from which the helical pile foundation moves as a result of the skewing relative to the ideal screw axis. Advantageously, the tension cable or tension chain is connected via a winding device to the rotary drive, the front end of the boom arm or the chucking device in such a way that the shortening of the effective length of the tension cable or tension chain as a result of screwing the helical pile foundation into the ground is compensated for, so that the force exerted by the counter-support on the helical pile foundation during installation remains substantially constant.
More preferably, the additional counter-support is embodied as a tie rod or push rod, i.e., as a substantially rigid component that can compensate for the tensile forces or compressive forces that occur as a result of the skewing moment. If the additional counter-support is attached to the side of the rotary drive, the front end of the boom arm, or the chucking device in such a way that only tensile forces have to be compensated for by the additional counter-support, the dimensioning of the tie rod can be made smaller than, for example, in the case of a push rod, because the problem of buckling forces does not exist with a tensile load. Preferably, the additional counter-supports are telescopic in the form of the tie rod or push rod, so that both forces can be absorbed and corresponding changes in length can be compensated for in order to maintain a constant counter-support force.
The additional counter-support is preferably hydraulically coupled to the drive torque of a rotary drive embodied as a hydraulic motor. The various units that can be connected to an excavator arm are usually supplied with hydraulics, so that the preferred design for the counter-support is for the rotary drive to be embodied as a hydraulic motor that receives the hydraulic power from the excavator.
Preferably, the additional counter-support is designed in such a way or is able to absorb such forces that a force component is generated which compensates for the skewing moment, acts counter to the deflection force on the helical pile foundation caused by the drive torque, and is so great that the helical pile foundation does not drift out of its desired installation direction while being screwed into the ground.
The counter-support is preferably designed or acts on the rotary drive, on the front end of the boom arm, or on the chucking device in such a way that, in addition to the lateral force component acting counter to the skewing moment, a force component acts in the installation direction, thus enabling the screwing process to be additionally supported.
Further advantages, potential applications, and details of the rotary driver according to the invention, which is attached to the boom arm of an excavator forming a counter-support and is used for screwing in a helical pile foundation, are described in the enclosed drawing, in which:
The state shown in
It will readily be understood that the additional counter-support 4 can be embodied not only as a tie rod 4.3 (see
- 1 rotary driver
- 2 helical pile foundation
- 3 boom arm, excavator
- 4 additional counter-support
- 4.1 tension cable
- 4.2 tension chain
- 4.3 tie rod
- 5 excavator
- 6 hydraulic motor
- 7 chucking device
- 8 housing of hydraulic motor
- 9 lateral forces
- 10 longitudinal forces/force couple
- 11 drive torque of hydraulic motor
- 12 control plunger
Claims
1. A rotary driver for a helical pile foundation attached to a boom arm of an excavator forming a counter-support, by means of which the helical pile foundation can be screwed into or out of a ground and which has a rotary drive that is arranged at the front end of the boom arm and transmits a drive torque to the helical pile foundation, as well as a chucking device for the helical pile foundation, wherein
- an additional counter-support acts on the rotary drive, on the front end of the boom arm, or on the chucking device and is anchored in the ground, which counter-support at least partially compensates for the force acting laterally to the plane of extension of the boom arm on the helical pile foundation.
2. The rotary driver as set forth in claim 1, wherein the additional counter-support is embodied as a tension cable or a tension chain.
3. The rotary driver as set forth in claim 1, wherein the additional counter-support is embodied as a tie rod or a push rod.
4. The rotary driver as set forth in claim 1, wherein the rotary drive is supplied with power from the excavator.
5. The rotary driver as set forth in claim 4, wherein the rotary drive is a hydraulic motor.
6. The rotary driver as set forth in claim 5, wherein the additional counter-support is hydraulically coupled to the drive torque of the hydraulic motor.
7. The rotary driver as set forth in claim 1, wherein the additional counter-support generates such a force component acting counter to the deflection force caused by the drive torque on the helical pile foundation that the helical pile foundation can be prevented from drifting out of its desired installation direction while it is being screwed in.
8. The rotary driver as set forth in claim 7, wherein the additional counter-support is designed in such a way that there is a force component acting in the installation direction and supporting the installation process.
9. The rotary driver as set forth in claim 2, wherein the rotary drive is supplied with power from the excavator.
10. The rotary driver as set forth in claim 3, wherein the rotary drive is supplied with power from the excavator.
11. The rotary driver as set forth in claim 2, wherein the additional counter-support generates such a force component acting counter to the deflection force caused by the drive torque on the helical pile foundation that the helical pile foundation can be prevented from drifting out of its desired installation direction while it is being screwed in.
12. The rotary driver as set forth in claim 3, wherein the additional counter-support generates such a force component acting counter to the deflection force caused by the drive torque on the helical pile foundation that the helical pile foundation can be prevented from drifting out of its desired installation direction while it is being screwed in.
13. The rotary driver as set forth in claim 4, wherein the additional counter-support generates such a force component acting counter to the deflection force caused by the drive torque on the helical pile foundation that the helical pile foundation can be prevented from drifting out of its desired installation direction while it is being screwed in.
14. The rotary driver as set forth in claim 5, wherein the additional counter-support generates such a force component acting counter to the deflection force caused by the drive torque on the helical pile foundation that the helical pile foundation can be prevented from drifting out of its desired installation direction while it is being screwed in.
15. The rotary driver as set forth in claim 6, wherein the additional counter-support generates such a force component acting counter to the deflection force caused by the drive torque on the helical pile foundation that the helical pile foundation can be prevented from drifting out of its desired installation direction while it is being screwed in.
Type: Application
Filed: Nov 21, 2022
Publication Date: May 25, 2023
Inventors: Günther Thurner (Strasskirchen), Martin Thurner (Strasskirchen)
Application Number: 17/991,021