EP4001509B1 - Method and construction machine for soil compaction - Google Patents

Description

The invention relates to a method for soil compaction with a construction machine, in which a carrying cable is guided along a mast, the carrying cable is wound up and unwound by means of a rotatably mounted winch drum of a cable winch, the winch drum is driven in rotation by means of a winch drive and a compacting element is arranged on the carrying cable which is moved vertically by the suspension cable, the suspension cable being unwound from the winch drum of the cable winch and the compaction element being lowered from a position above a floor surface on the suspension cable down to the floor surface, the compaction element striking the floor surface and thereby hitting the floor compressed, according to the preamble of claim 1.

The invention also relates to a construction machine for soil compaction with a mast, a carrying cable which is guided along the mast, a cable winch with a rotatably mounted winch drum on which the carrying cable is attached for winding and unwinding, a winch drive for driving the winch drum in rotation, a A compacting element attached to the suspension cable for vertical movement, and a control unit by which the cable winch is operable to unwind the suspension cable from the winch drum, the compaction element on the suspension cable being lowered to a ground surface and the compacting element being raised to compact the ground hitting the ground surface, according to the preamble of claim 11.

A generic construction machine is, for example, from the EP 3 708 528 A1 out.

When a compaction element is lowered by means of such a construction machine, it is usually provided that after the compaction element hits the ground, the winch drum is braked by means of a corresponding braking device. Since the compression element strikes a ground surface at a relatively rapid lowering speed, so-called slack rope and undesired rope oscillations can form on the support rope, which continues over the masthead to a winch drum. This rope oscillation can cause rope wraps on the winch drum to jump out of their intended position. With further operation of the winch drum, this can lead to incorrect winding of the carrying cable on the winch drum, with the cable crossing the grooves on the drum.

Such a disorderly winding of the rope on the winch drum can lead to damage to the winch drum and in particular to increased wear of the support rope. As a result, not only can the service life of the suspension cable be significantly reduced, but the maximum load capacity of the suspension cable can also be impaired overall.

To ensure proper winding, the teaches EP 3 708 528 A1 to provide a rope pressure device with at least one pressure element in the area of the winch drum. As a result, the cable vibration of the support cable can be reliably prevented from spreading to the cable area wound up on the winch drum. The rope pressing device means an additional design effort and is associated with a corresponding space requirement on the construction machine. Furthermore, the rope pressing device also requires maintenance at certain time intervals.

The invention is based on the task of specifying a method and a construction machine for soil compaction, with which the negative effects of cable vibration of the supporting cable on the cable winding on the winch drum are counteracted in a particularly efficient manner.

The object is achieved according to the invention on the one hand by a method having the features of claim 1, 6 or 9 and on the other by a construction machine with the Features of claim 11 solved. Preferred embodiments of the invention are given in the dependent claims.

A method for soil compaction according to the invention is characterized in that the winch drum is decoupled from the winch drive via a coupling device when the support cable is being unwound, that before the compaction element strikes the ground surface the winch drive is driven in a direction of rotation for winding up the support cable and that after the When the compacting element hits the ground surface, the coupling device couples the winch drum to the winch drive, which is already rotating.

The invention is based on the knowledge that insufficient tension of the suspension cable in the area of the winch caused by cable vibration can result in cable windings on the winch drum jumping out of their intended position. According to the method according to the invention, the winch drive is decoupled from the winch drum via a coupling device when the support cable is unwound in a period of time before the compression element hits the ground surface. The movement of the winch drum is therefore independent of the movement of the winch drive. This independence can be used to operate the winch drive early in a direction of rotation, which is required to wind up the suspension cable. The coupling device allows the winch drum to be reconnected or coupled to the winch drive, particularly immediately after the compaction element has struck the ground surface, whereby the torque of the winch drive applied to the drive shaft can have a direct effect on the winch drum and a resulting abrupt starting rotary movement of the winch drum Direction of winding up the support rope leads to very rapid rope tension in the area of the winch.

The usual start-up phase of a winch drive is avoided. According to the invention, immediately after or when the compression element hits the ground surface, a winding force can be applied to the support cable via the winch drum, so that it is immediately tightened again in the area of the winch. Due to this immediately adjusting rope tension a formation of slack rope in the winch and the associated jumping of rope windings on the winch drum from their intended position counteracted to a considerable extent. This reduces the risk of unwanted misalignment of rope windings on the winch drum.

In principle, the carrying cable can be connected directly to the compression element. A chain and/or a steel cable hanger is preferably arranged as a buffer between the support cable and the compression element. As a result, compression of the carrying cable by standing on the compression element can be avoided when braking. In the case of a steel cable hanger, at least one additional weight, for example in the form of a steel traverse, can optionally be arranged between the support cable and the steel cable hanger.

In principle, the soil compaction process can be carried out manually by a machine operator. According to a development of the invention, it is particularly advantageous that the method is carried out automatically by means of a control unit. The control unit can in particular be connected to the winch drive and the clutch device and actuate them accordingly. The control unit can also be connected to one or more sensors, by means of which a position of the compression element and/or the cable tension is detected. The clutch device can be designed as a lockable overrunning clutch, with locking or unlocking being able to be effected by the control unit.

In principle, the coupling device can be designed in any suitable manner. According to a further development of the invention, it is particularly expedient for the coupling device to comprise a free-fall brake, with the carrying cable being unwound when the compression element is in free fall. After opening the brake, a free-fall brake allows the winch drum to be driven with low friction solely by the weight of the compression element attached to the supporting cable, with the compression element being able to hit the ground surface in free fall, so to speak. In this free fall, there is a certain minimum tensile stress on the suspension cable. The free-fall brake can be used electronically or by appropriate mechanical components to prevent a free-fall when it hits the ground and there is a reduction in cable tension. or free-running mode are ended, with a coupling, ie the production of a torque-transmitting connection, being produced directly between the winch drive and the winch drum. The free-fall brake, which can be part of the clutch device or form it as a whole, can be connected to the control unit, which can basically include an electronic computer unit.

In principle, the clutch device can be actuated at any point in time. A preferred method variant of the invention consists in the coupling device carrying out a coupling when the compacting element reaches the ground surface. This ensures that, on the one hand, the compression element falls as freely as possible and, on the other hand, torque is transmitted from the winch drive to the winch drum immediately after it hits the ground in order to generate the desired cable tension of the carrying cable in the area of the winch.

In principle, any torque can be set on the winch drive for any period of time. According to a development of the method according to the invention, it is advantageous that a tightening torque is generated by the winch drive when coupling, by means of which the carrying cable is tensioned in the area of the winch. The tightening torque can preferably be designed in such a way that this leads to a desired cable tension, but the compression element is not lifted from the ground. A second, higher torque can then be set for lifting. However, it is also possible to set a tightening torque at which the compression element is immediately lifted so that it can be moved back to a starting position above the ground surface in order to carry out a further compression process.

According to one embodiment of the method, it is provided that after the compaction element has hit the ground, the carrying cable in the area of the winch is first briefly stretched and then, before the compacting element is lifted from the ground again, the carrying cable is automatically unwound from the winch drum by a certain amount by the control unit becomes. Preferably, the carrying cable is wound up again immediately afterwards.

According to this method according to the invention, it is provided to counteract an incorrect winding of the carrying cable on the winch drum by first briefly tensioning the carrying cable in the region of the winch without lifting the compression element from the ground. Subsequently, before the compression element is lifted from the ground, the carrying cable tensioned in this way is automatically unwound and relaxed by the control unit by a certain amount, any misalignment of the winding on the winch drum that may have occurred being removed again by unwinding.

The carrying cable can then be automatically wound up again by the control unit and the compaction element can be lifted off the ground until the compaction element again reaches the desired starting position above the ground for a renewed compaction process.

With this method according to the invention it is ensured that even if an offset occurs on the cable winding, this is automatically and reliably eliminated again by the control unit and thus no permanent incorrect winding of the support cable can form on the winch drum. This also reliably counteracts cable wear.

The amount or degree of unwinding of the suspension cable before lifting the compression element again by winding up the suspension cable can be adjusted in any suitable manner. According to a further development of the invention, it is particularly advantageous that the carrying cable is unwound until the carrying cable is wound correctly on the winch drum. This ensures clean winding over the long term and therefore less wear and tear on the suspension cable.

With a corresponding arrangement of the winch drum on a construction machine, the winding can be observed directly by a machine operator from a control cabin. Clean cable winding can also be ensured with any arrangement of the winch drum according to a further development of the invention by using a sensor unit, in particular a camera unit or a radar unit or another suitable sensor, to detect a winding of the suspension cable on the winch drum. The image of the camera unit for example, it can be displayed to a machine operator in the machine cabin. Detection can take place optically, without contact using energy waves, tactilely, electronically, magnetically, by reed contact or in any other suitable manner.

Alternatively or additionally, the sensor unit can be connected to the control unit, which uses signals or data recorded by the sensor unit to determine whether the winding on the winch drum is correct. The signal or the data can in particular be an image. The sensor signal recorded for the rope winding is evaluated electronically, for example with image processing software. Depending on a possible misalignment of a cable winding on the winch drum, the machine operator or the control unit can set an amount or a measure of the unwinding of the support cable individually until the cable winding on the winch drum is correct. The amount of unwinding can be specified as an angle of rotation for the winch drum or a length for the carrying cable or a period of time for the control of the winch drive (at a defined speed).

According to a further development of the method according to the invention, it is provided that the amount of unwinding of the support cable is set automatically by the control unit or by a machine operator before a renewed lifting process of the compression element. The amount can be constant or variable.

With regard to the construction machine, the invention is characterized in that a control unit is provided, which is designed to carry out one of the methods for soil compaction described above. The control unit can in particular be an electronic control unit and in particular can be integrated into an existing control unit of a construction machine.

In principle, the winch drum can also be arranged directly on the mast and in particular in an upper region of the mast. According to a further development of the invention, it is particularly expedient for the carrying cable to be guided over a mast head at the upper end of the mast. The winch drum and the winch drive can thus be provided directly or close to a carrier device be so that the construction machine as a whole has as low an overall center of gravity as possible.

The carrier device can in particular have an undercarriage with an uppercarriage rotatably mounted thereon. The undercarriage can in particular include a chassis, in particular a crawler chassis.

To ensure correct winding on the winch drum, it is expedient according to a development of the invention for at least one sensor unit, in particular a camera unit, a radar unit or an ultrasonic sensor or another suitable sensor, to be installed in the area of the winch drum for detecting a winding of the suspension cable the winch drum is arranged.

Fig. 1

eine Seitenansicht einer erfindungsgemäßen Baumaschine, und

Fig. 2

eine perspektivische Detailansicht einer Windentrommel.

The invention is explained in more detail below using a preferred exemplary embodiment, which is illustrated schematically in the attached drawings. In the drawings show:

1

a side view of a construction machine according to the invention, and

2

a perspective detailed view of a winch drum.

A constructed as a crawler crane construction machine 10 of the invention 1 has a mobile carrier device 12 . The carrier device 12 includes a crawler chassis 14 on which an upper carriage 15 is rotatably mounted. A mast 16 is mounted on the superstructure 15 so as to be pivotable about a horizontal pivot axis and is also referred to as a cantilever arm. In order to pivot the mast 16, a holding beam 26, a support beam 28 and an adjusting cable mechanism 27 are provided on the superstructure 15 in a manner which is basically known.

At least one carrying cable 20 is guided from the superstructure 15 via a mast head 18 of the mast 16, on which a compacting element 30 is suspended, which in the exemplary embodiment shown is designed as an impact weight 32 for soil compaction. In the exemplary embodiment, the carrying cable 20 is driven in an adjustable manner via a double winch arrangement in the upper carriage 15, as is known in principle from the prior art. In order to avoid cable vibration, a cable pressing device 40 can be arranged on each of the two sections of the support cable 20, one of which on the support beam 26, also called A-frame, and the other is attached to the mast 16. The ends of the supporting cable 20 are each attached to a cable winch in the superstructure 15, so that a double cable winch arrangement is provided for fast lifting processes. A control unit can be provided on the superstructure 15, in particular in a cabin.

According to 2 a possible arrangement of a cable winch 22 for the construction machine 10 according to the invention is shown. The cable winch 22 has a winch drum 24 for winding and unwinding the carrying cable 20 . The winch drum 24 can be driven in rotation in basically both directions of rotation via a winch drive 23 shown only partially via an interposed coupling device 25 .

The clutch device 25 can be designed as a lockable overrunning clutch or a so-called free-fall brake, with the carrying cable 20 being unwound solely by the weight of the compression element 30 in free fall, so to speak. When the compaction element 30 hits a ground surface for soil compaction, the coupling device 25 can immediately reestablish a non-rotatable connection between the winch drive 23 and the winch drum 24 .

According to the invention, provision is made for the winch drive 23 to be driven, preferably via the control unit, in a winding-up direction, clockwise in the exemplary embodiment shown, before a new connection is made by the coupling device 25 . Thus, a tightening torque of the winch drive 23 is applied to the winch drum 24 immediately when the coupling device 25 is coupled. A desired tension of the support cable 20 in the area of the cable winch 22 can thus be brought about. This effectively counteracts the formation of slack rope and in particular the transmission of a rope vibration of the suspension rope 20 to the winding of the suspension rope 20 on the winch drum 24 . A camera unit 50 as a sensor unit can monitor a clean winding of the supporting cable 20 on the winch drum 24 . Instead of the camera unit 50, a radar unit, ultrasonic or other suitable sensor such. B. an optical sensor, a magnetic sensor or a reed contact can be used.

Depending on the image or sensor signal captured by the camera unit 50 or the sensor signal displayed, a machine operator or preferably automatically via the control unit can unwind the support cable 20 on the winch drum 24 if an undesired offset of the support cable 20 occurs before the compression element 30 being lifted off the ground again.

In particular, after a cable vibration has calmed down, the winch drum 24 can be used to wind it up cleanly, with the compression element 30 then being lifted off the ground. A clean winding of the suspension cable 20 on the winch drum 24 can thus be established.

In addition, a fundamentally known further rope pressure device 40 with a plate-shaped pressure element 42 can be provided on the winch drum 24 . The pressure element 42 is movably mounted by means of a base support 46 and can be pressed against the cable winding on the winch drum 24 by means of a pressure cylinder 48 to additionally avoid a cable offset.

Claims (13)

1. Method for soil compaction using a construction machine (10), wherein

   - a support cable (20) is guided along a mast (16),

   - the support cable (20) is wound and unwound by means of a rotatably mounted winch drum (24) of a cable winch (22),

   - the winch drum (24) is driven in rotation by means of a winch drive (23), and

   - there is arranged on the support cable (20) a compacting element (30) which is moved vertically by the support cable (20), wherein the support cable (20) is unwound from the winch drum (24) of the cable winch (22) and the compacting element (30) is lowered from a position above a soil surface on the support cable (20) to the soil surface, wherein the compacting element (30) strikes the soil surface and the soil is thereby compacted,
   characterised in that

   - the winch drum (24) is uncoupled from the winch drive (23) by means of a coupling device (25) while the support cable (20) is being unwound,

   - even before the compacting element (30) strikes the soil surface, the winch drive (23) is driven in a rotational direction for winding the support cable (20), and

   - after the compacting element (30) has struck the soil surface, the coupling device (25) couples the winch drum (24) with the winch drive (23) which is already being driven in rotation.
2. Method according to claim 1,
   characterised in that
   the method is carried out automatically by means of a control unit.
3. Method according to claim 1 or 2,
   characterised in that
   the coupling device (25) comprises a free-fall brake, wherein the support cable (20) is unwound in the event of free fall of the compacting element (30).
4. Method according to any one of claims 1 to 3,
   characterised in that
   when the compacting element (30) reaches the soil surface, the coupling device (25) carries out coupling.
5. Method according to any one of claims 1 to 4,
   characterised in that
   a tightening torque is generated by the winch drive (23) in coupling, by means of which tightening torque the support cable (20) is tensioned in the region of the cable winch (22).
6. Method according to any one of claims 1 to 5,
   characterised in that
   after the compacting element (30) has struck the soil, the support cable (20) is first tensioned in the region of the cable winch (22) and then, before the compacting element (30) is lifted from the soil again, the support cable (20) is automatically unwound by the control unit from the winch drum (24) by a certain amount, which can preferably be set by the driver of the machine.
7. Method according to claim 6,
   characterised in that
   the support cable (20) is unwound until the support cable (20) is wound correctly on the winch drum (24).
8. Method according to either claim 6 or claim 7,
   characterised in that
   the amount by which the support cable (20) is unwound before the compacting element (30) is lifted again is set by a machine operator or automatically by a control unit.
9. Method according to any one of claims 1 to 8,
   characterised in that
   winding of the support cable (20) on the winch drum (24) is detected by means of a sensor unit, in particular a camera unit (50) or a radar unit.
10. Method according to claim 9,
    characterised in that
    the sensor unit is in communication with a control unit which determines, on the basis of a signal acquired from the sensor unit, whether there is correct winding on the winch drum (24).
11. Construction machine for soil compaction, comprising

    - a boom (16),

    - a support cable (20) which is guided along the boom (16),

    - a cable winch (22) having a rotatably mounted winch drum (24) to which the support cable (20) is attached for winding and unwinding,

    - a winch drive (23) for driving the winch drum (24) in rotation,

    - a compacting element (30) which is arranged on the support cable (20) for vertical movement, and

    - a control unit by means of which the cable winch can be operated to unwind the support cable (20) from the winch drum, wherein the compacting element (30) is lowered on the support cable (20) to a soil surface and the compacting element (30) strikes the soil surface in order to compact the soil,

    characterised in that
    there is provided a control unit which is configured to carry out the method for soil compaction according to any one of claims 1 to 10.
12. Construction machine according to claim 11,
    characterised in that
    the support cable (20) is guided by way of a boom head (18) at the top end of the boom (16).
13. Construction machine according to claim 11 or 12,
    characterised in that
    there is arranged in the region of the winch drum (24) at least one sensor unit, in particular a camera unit (50) or a radar unit, for detecting incorrect winding of the support cable (20) on the winch drum (24).

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