CRANE

Abstract

The present invention relates to a crane with a height-adjustably mounted control or personnel stand that can be lifted and lowered by at least two lifting elements, wherein the two lifting elements are articulated to a balancing rocker that is mounted on a rocker bearing head connected to the control or personnel stand so as to be luffable about a horizontal pivot axis, wherein a monitoring and/or safety device is provided to monitor and/or ensure the safety of the control stand. According to the invention, the pivot axis is configured as a measurement axis for detecting the load state of the luffable bearing of the balancing rocker and for providing a load signal to the monitoring and/or safety device.

Claims

1. A fast-erecting crane comprising: a telescopable and/or luffable tower with a height-adjustable mounted control and/or personnel stand configured to be lifted and lowered by two lifting elements, wherein the two lifting elements are articulated to a balancing rocker that is luffably mounted on a rocker bearing head connected to the control and/or personnel stand about a horizontal pivot axis; a monitoring and/or safety device for monitoring the control and/or personnel stand, wherein the pivot axis is configured as a measurement axis for detecting the load state of the luffable bearing of the balancing rocker and for providing a load signal to the monitoring and/or safety device.

2. The crane of claim 1, further comprising a lever mechanism for generating a change of the measurement axis load acting on the measurement axis in dependence on a rotation of the balancing rocker relative to the rocker bearing head, and wherein the lever mechanism is associated with the balancing rocker and/or the rocker bearing head and/or the measurement axis.

3. The crane of claim 2, wherein the lever mechanism is configured to convert a holding and/or braking moment occurring during limiting and/or braking of the rotation of the balancing rocker with respect to the rocker bearing head into a load acting on the measurement axis.

4. The crane of claim 1, further comprising pivot stops on the balancing rocker and the rocker bearing head, wherein the pivot stops are out of engagement in a non-deflected neutral position of the balancing rocker and come into engagement when reaching a predetermined swivel position of the balancing rocker and block a further swivel movement of the balancing rocker relative to the rocker bearing head.

5. The crane of claim 4, wherein the pivot stops are arranged on a partial circle around the measurement axis and/or adjacent to the outer circumference of the measurement axis.

6. The crane of claim 5, wherein said partial circle has a diameter of less than 300% of the outside diameter of the measurement axis.

7. The crane of claim 6, wherein the pivot stops are in a horizontal plane transverse to the luffing axis of the lifting elements.

8. The crane of claim 7, wherein the pivot stops in their engaged position are configured to generate an abutment force eccentrically to the axis of rotation.

9. The crane of claim 4, wherein the pivot stops are in a horizontal plane transverse to the luffing axis of the lifting elements.

10. The crane of claim 4, wherein the pivot stops in their engaged position are configured to generate an abutment force eccentrically to the axis of rotation.

11. The crane of claim 1, further comprising an evaluating device for evaluating the measurement signal of the measurement axis, wherein the evaluating device is configured to employ a height and/or a change of the measurement signal of the measurement axis to distinguish between an overload of the control and/or personnel stand at a proper operating condition of the lifting elements and the balancing rocker, and a malfunction of the lifting elements and/or the balancing rocker.

12. The crane of claim 11, wherein the evaluating device is configured to compare the measurement signal of the measurement axis with at least a first threshold value and a second threshold value, wherein the first threshold value characterizes the load acting on the measurement axis on transition between maximum permissible load and overload of the control and/or personnel stand at a proper operating condition of the lifting elements and the balancing rocker, and wherein the second threshold value characterizes an increase of the load acting on the measurement axis with an excessive deflection of the balancing rocker from its neutral position.

13. The crane of claim 1, wherein the measurement axis is non-rotatably attached to the rocker bearing head, and wherein the balancing rocker is retained at the measurement axis so as to be rotatable relative to the measurement axis.

14. The crane of claim 1, wherein the measurement axis is configured to detect transverse forces acting on the measurement axis in terms of their amount and/or direction.

15. The crane of claim 1, wherein the measurement axis is configured to detect bending moments acting on the measurement axis.

16. The crane of claim 1, wherein the measurement axis comprises a sensor system, a strain gauge and/or a strain-sensitive thin-film coating and/or a magnetic field-based sensor array.

17. The crane of claim 1, wherein the rocker bearing head is rigidly attached to the control and/or personnel stand.

18. The crane of claim 1, wherein the at least two lifting elements are each configured as flexurally slack traction elements, in particular lifting cables.

19. The crane of claim 1, wherein the balancing rocker defines a triangle with its articulation points of the lifting elements and the pivot axis, wherein the articulation points of the lifting elements are along a straight line above the pivot axis.

20. The crane of claim 19, wherein in the non-deflected neutral position of the balancing rocker the pivot axis is positioned on the balancing rocker centrally between the articulation points of the lifting elements.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The present invention will subsequently be explained in detail with reference to a preferred exemplary embodiment and associated drawings, in which:

[0040] FIG. 1: shows a schematic side view of a fast-erecting crane configured as a tower crane according to an advantageous embodiment of the invention, whose crane operator cabin is height-adjustably mounted on the tower of the crane;

[0041] FIG. 2: shows a perspective representation of the crane operator cabin of FIG. 1 and its suspension;

[0042] FIG. 3: shows a perspective representation of the suspension of the crane operator cabin of FIG. 2, which shows the balancing rocker with the two lifting cables articulated thereto as well as the measurement axis by which the balancing rocker is pivotally articulated to the rocker bearing head of the suspension;

[0043] FIG. 4: shows a top view of the balancing rocker and the measurement axis of the suspension from the preceding Figures, wherein the balancing rocker is shown in a non-deflected neutral position in which the pivot stops are out of engagement; and

[0044] FIG. 5: shows a top view of the balancing rocker and the measurement axis similar to FIG. 4, wherein the balancing rocker is shown in a position that is rotated due to the breakage or a slack cable of one of the lifting cables, in which position the pivot stops have come into engagement.

DETAILED DESCRIPTION

[0045] As shown in FIG. 1, the crane 1 can be configured as a tower crane and have a tower 2 which is upright in operation and carries a cantilevered boom 3. With its lower end, the tower 2 can sit on a turntable 4 that is rotatable about an upright axis and is supported on an undercarriage 5 which can be configured as a truck or can be traversable in some other way, but possibly can also form a rigid, non-traversable supporting base.

[0046] A trolley 7 can be mounted on the boom 3 so as to be longitudinally traversable, which trolley can be moved to and fro by means of a trolley cable 8. Via the trolley 7, a lifting cable 6 comprising a load hook can be unwound.

[0047] The crane 1 comprises a control and/or personnel stand 9 that can be configured as a crane operator or elevator cabin 10. Said control and/or personnel stand 9 is height-adjustably mounted. In particular, said crane operator or elevator cabin 10 can be mounted on the tower 2 so as to be longitudinally traversable, for example by a cabin traveling gear that is guided on the tower profile, for example on its longitudinal beams.

[0048] As is shown in FIGS. 2 to 5, the control and/or personnel stand 9 can be retained and be brought into various height positions via a suspension 11 that can engage the chassis, in particular the upper surface of the crane operator or elevator cabin 10. Said cabin 10 can be moved up and down on an outside of the tower 2, for example by means of a roller guide or rail guide along the tower. Possibly, however, the cabin can also be arranged in the interior of the tower profile, for example when it is only utilized as a climbing aid to reach the boom or a control stand arranged at the top, and the tower profile is voluminous enough.

[0049] Said suspension 11 in particular can comprise a balancing rocker 12 to which two lifting elements 13 in the form of lifting cables can be articulated, which can be lifted and lowered via a suitable lifting gear drive. For example, two cable drums can be provided to wind and unwind the two lifting cables.

[0050] By means of a pivot axis 14 which extends horizontally and engages a central portion of the balancing rocker 12, said balancing rocker 12 is pivotally mounted on a rocker bearing head 15 which can be rigidly connected to the control stand 9, in particular attached to the chassis of the cabin 10.

[0051] As is shown in FIG. 3, said rocker bearing head 15 can form a bearing yoke, for example, between whose legs the balancing rocker 12 dips with a bearing portion, wherein the legs of the rocker bearing head 15 and the bearing portion of the balancing rocker 12 can include aligned pivot bearing bores, through which said pivot axis 14 extends. In principle, however, it would also be possible to reverse the arrangement, for example to provide two yoke legs at the bearing portion of the balancing rocker 12, between which the rocker bearing head 15 extends. Further configurations for example in the manner of a cantilevered pivot bearing connection would also be possible.

[0052] Said pivot axis 14 is configured as a measurement axis 16 in order to detect the transverse forces acting on the pivot axis 14. Said measurement axis 16 can be configured in the manner of a force measuring bolt, wherein a suitable sensor system can be provided on the measurement axis 16, which can detect said bearing forces and loads that act on the bolt. As mentioned above, said sensor system 17 can comprise for example strain gauges on the measurement axis or a thin-film coating applied thereon in order to measure deformations and hence loads.

[0053] As is shown by a comparison of FIGS. 4 and 5, said measurement axis 16 can be non-rotatably held at the rocker bearing head 15 so that it does not follow rotary movements of the balancing rocker 12. Alternatively, the measurement axis 16 can also be rotatably mounted relative to the rocker bearing head 15 and/or to the balancing rocker 12 so that it does not assume a predetermined rotational position.

[0054] The pivotability of the balancing rocker 12 relative to the rocker bearing head 15 advantageously can be limited by pivot stops 18 that can be provided on the balancing rocker 12 and the rocker bearing head 15. In particular, said pivot stops 18 can be arranged around the pivot axis 14 in the direct vicinity of its outer circumference, i.e. in particular around the bearing bores through which the pivot axis 14 extends.

[0055] For example, said pivot stops 18 can be formed by protrusions that are formed on the balancing rocker 12 and the rocker bearing head 15 so as not to collide with each other when the balancing rocker 12 pivots relative to the rocker bearing head 15.

[0056] As is shown in FIGS. 4 and 5, said pivot stops 18 can be out of engagement with each other in a non-deflected neutral position of the balancing rocker 12, which is shown in FIG. 4, so that the balancing rocker 12 can rotate out of the neutral position unimpededly. On the other hand, the pivot stops 18 come into engagement when the balancing rocker has carried out a predetermined swivel movement, for example by an angle of about +/−10° to +/−20°.

[0057] When the pivot stops 18 come into engagement with each other, as is shown in FIG. 5, for example because one of the lifting elements 13 is broken or has been unwound too far, the load state at the measurement axis 16 changes significantly. The eccentrically arranged pivot stops 18 and the forces transmitted thereby exert additional forces on the pivot axis 14, which must balance the lever situation. The loads detected on the measurement axis 16, in particular transverse forces and/or bending moments, undergo a significant change as soon as the pivot stops 18 come into engagement. This change in principle can be the removal of a load or an additional load, which can be detected on the measurement axis.

[0058] Advantageously, said pivot stops 18 are configured such that engagement forces are obtained on the abutment surfaces in engagement with each other, which are eccentric with respect to the pivot axis 14 and/or have a lever arm in order to generate a reaction in the measurement axis. In particular, a resultant engagement force can act eccentrically to the measurement axis when pivot stops are in engagement.

[0059] As is shown in FIGS. 4 and 5, the pivot stops 18 can comprise two pairs of pivot stops 18, which are arranged on opposite sides of the measurement axis 16, preferably more or less—at least approximately—in a plane that extends horizontally through the pivot axis 14. For example, the pivot stops 18 can extend in a range of 2 o'clock to 4 o'clock or 8 o'clock to 10 o'clock when the pivot axis 14 is viewed in its axial direction.

[0060] The pivot stops 18 advantageously are arranged in such a way that depending on the tilting movement of the balancing rocker always only one pair of stops comes into engagement on one side of the pivot axis 14.

[0061] The pivot stops 18 form a lever mechanism that converts the torque or holding moment occurring on limitation of the swivel movement of the balancing rocker 12 into a significant change of the load acting on the measurement axis 16. In particular, the lever mechanism formed by the pivot stops 18 can multiply the load introduced into the suspension by the cabin, so that the load acting on the measurement axis 16 increases distinctly, in particular increases very much more than would be the case when the permissible load capacity is exceeded only slightly, for example on entry of an additional person.

[0062] As is shown in FIG. 5, what is obtained when a pivot stop pair comes into engagement during a correspondingly far rotation of the balancing rocker, on the one hand is a lever arm of the measurement axis or of the cabin load going through the measurement axis relative to the pivot stop pair in engagement and on the other hand a lever arm of the still carrying cable 13 relative to the pivot stop pair 18, wherein said lever arms each substantially can correspond to the horizontal distance between the center of the measurement axis and the point of engagement of the pivot stops on the one hand and the line of action of the cable tractive force and the point of engagement of the pivot stops 18 on the other hand.

[0063] As the cable force in the still carrying cable 13 corresponds to the load of the cabin along with payload and attachment parts, so that a vertical equilibrium of forces can be obtained, the change of the load obtained on the measurement axis can be controlled by the length of said lever arms.

[0064] For example, the length of said lever arms can be formed by a corresponding design of the geometry of the balancing rocker and the rocker bearing head, in particular the articulation point of the lifting elements 13 at the balancing rocker and the arrangement of the pivot stops 18 in such a way that the load occurring on the measurement axis 16 and hence measured increases by 50% or more, when said pivot stops 18 come into engagement due to a corresponding swivel movement of the balancing rocker 12. For example, when the cabin 10 along with a permissible, maximum payload has a weight of 1000 kg, said lever arms can be adjusted such that a load of 1500 kg occurs on the measurement axis 16 when the pivot stops 18 come into engagement. In so far, it is easy to distinguish between a normal overload and a cable breakage or a faulty spooling, for example when a first threshold value of 1050 kg is exceeded and a second threshold value of for example 1400 kg is not exceeded yet, so that a normal overload with a still operable suspension can be assumed, while in the event of an exceedance of said second threshold value of for example 1400 kg a cable breakage or a faulty spooling can be assumed. Said values are to be understood merely by way of example.

[0065] The sensor system 17 associated with the measurement axis 16 emits a load signal which characterizes the load situation at the measurement axis 16, in particular the transverse forces obtained there in terms of their amount and/or in terms of their direction.

[0066] Said load signal of the sensor system 17 can be evaluated by a control device 20 of the crane 1, which control device 20 is of the electronic type and for example can comprise a microprocessor that can execute a control program stored in a memory.

[0067] Said control device 20 can include an evaluating device 19 that evaluates the measurement signal of the measurement axis 16 in the above-mentioned way, in particular compares the same with two threshold values which on the one hand characterize the normal transition from a normal, permissible load capacity to an overload and on the other hand characterize the engagement of the pivot stops 18 and the resulting change of the load acting on the measurement axis.

[0068] Said control device 20 on the one hand can emit a warning signal and/or at least stop one drive of the crane, in particular the lifting gear drive for the height adjustment of the control stand 9, when the load signal of the sensor system 17 indicates an exceptional load state, for example excessive transverse forces on the measurement axis.

[0069] Alternatively or additionally, however, said control device 20 possibly can also intervene in the actuation of the drives by way of precaution. For example, when the sensor system 17 detects that the balancing rocker tilts too strongly, the control device 20 can try to adjust the lifting gear drive from which the lifting cable that is too slack or too tight is unwound.

[0070] Alternatively or additionally, the control device 20 can also emit a preventive maintenance signal when the load signals of the sensor system 17 still do not indicate a critical state, but already indicate significant changes with respect to the original load spectrum when new.