EP1979259A1

EP1979259A1 - Hook of a crane

Info

Publication number: EP1979259A1
Application number: EP07702625A
Authority: EP
Inventors: Ulrich Müller; Thorsten Seising; Detlef Sonnenschein; Andreas Tacke
Original assignee: BETR FORSCH INST ANGEW FORSCH; BFI VDEH Institut fuer Angewandte Forschung GmbH
Current assignee: BETR FORSCH INST ANGEW FORSCH; BFI VDEH Institut fuer Angewandte Forschung GmbH
Priority date: 2006-01-10
Filing date: 2007-01-09
Publication date: 2008-10-15
Anticipated expiration: 2027-01-09
Also published as: ATE482900T1; WO2007080090A1; DE502007005192D1; DE102006001423A1; EP1979259B1

Abstract

The invention relates to a lifting gear having a receptacle for receiving the component of a load, on which component the load is raised, and in particular to a hook (1) of a crane having at least one piezoelectric element (20) which is arranged in the region of the hook mouth (3) in such a way that it is loaded by the weight of a load which is carried by the hook (1), which weight is transmitted to the hook (1) via a journal (4) which is held in the hook mouth (3).

Description

Betriebsforschungsinstitut VDEh-Institute for Applied Research GmbH

Sohnstrasse 65, 40237 Dusseldorf

Hook of a crane

The invention relates to a hoist with a receptacle for receiving the component of a load on which the load is raised, and in particular a hook of a crane and in this particular possibility of monitoring the correct load pickup by the hook and takes the priority of the German patent application 10th 2006 001 423.5.

Already from the published in 1957 AT 192 857 the effort is known to monitor the load of a hook hook with a load cell, as the crane operator can hardly reasonably perform such monitoring due to its clear distance to the load hook position. AT 192 857 suggests on

Reason for the hook mouth to set up a load cell as a trigger contact. As soon as the hook loads the load cell, it emits a signal. By the arrangement of the load cell in the bottom of the hook mouth, the delivery of the signal is synonymous with the correct detection of the load, as the picked up by the hook jaw pin the load comes into contact only with the load cell when it is in the hook mouth. A disadvantage of the crane transport of molten masses in pans is the arrangement of the trip contact - load cell - in the power main circuit, which makes a to the usually large load matched load capacity and thus size of the contactor required. Furthermore, a patch on the jaw pressure cell reduced the depth of the hook mouth and thus the

Safety of the complete inclusion of the pin in the jaw, or the security against falling out of the pin with angled hook. DE 44 47 393 C1 teaches a further development of the known from AT 192 857 principle and proposes to provide two inductive sensors in the jaw of a lamellar hook of a huts crane. These sensors can determine the positive engagement of the hook mouth with the pin contactless. As a result, the construction known from DE 44 47 393 C1 can also be detected when the pin approaches the hook mouth.

Thus, a disadvantage of known from AT-PS 192 857 device is eliminated, which can not indicate the approach to the load, so that the crane operator may need to make several blind bumps before he has picked up the load properly.

The sensors respond to the approach of conductive, metallic objects. The sensors are installed in recesses of the jaw, which open to the jaw. These recesses are closed by a cover that does not affect the induction principle to the journal support side of the jaw.

When threading the Pfannengehängezapfens in the jaw takes place a switching of the output signal, if the defined switching distance of the sensors is exceeded, or a downshift, if the switching distance should be exceeded. Due to the geometric relationships between peg and jaw shell and the defined size of the switching distance is the proper

Position of the pin in the mouth socket clearly detected. This sensor arrangement takes into account both the safety requirements (two redundant sensors per hook) and the environmental conditions (encapsulation in the mouth shells).

A disadvantage of the construction known from DE 44 47 393 C1, that the inductive sensors must be provided in recesses of the inner surface of the mouth socket in order to determine the approach of the pin to the bottom of the jaw. In this case, the recess must not be closed with the inductive effect of the sensors influencing covers. Especially among the

Operating conditions of a steelworks that characterize high abrasive loads, especially dirt and scale, this design is disadvantageous or requires special, the elasticity limiting armor, since it can cause damage to the covers. Furthermore, it has been found in practical operation that this known construction nevertheless leads to incorrect measurements, for example, if metal splashes from the melt settle on the cover of the sensors. The inductively measuring sensors can not distinguish between these splashes of the melt and the pin of the load, so that a positive gauge is displayed, although the pin was not recorded in the hook mouth.

Against this background, the present invention seeks to propose a structure for a hoist with a receptacle for receiving the component of a load on which the load is raised, and in particular a structure for the hook of a crane, with which the recording of the male component can be reliably determined in the intended recording.

This object is solved by the subject matter of claim 1 and claim 10. Advantageous embodiments are specified in the subclaims.

The invention is based on the basic idea to determine the correct absorption of the load by the inclusion of a hoist, in which it is checked whether a weight is transmitted to the hoist in the area of the recording. For only in this way can it be determined with certainty that the element to be lifted, for example the pin to be picked up by the hook mouth, is actually located in the receptacle. To determine this weight transfer, the invention proposes to provide a force sensor in a recess of the hoist itself and to guide the recess so that it has no opening for receiving. However, the encapsulation of the force sensor in the hoist itself thereby weakens the hoist itself to a slight extent, but gives the measuring device a good temperature resistance in the absence of direct contact with the component of the load on which the load is lifted. Depending on the routing of the recess, the surrounding wall of the hoist even exerts an insulating effect.

Furthermore, the proposed measuring arrangement is insensitive to cottage dust, since contact with the cottage dust can be well avoided. This is often stored in recordings, such as those of the hoist from. According to the invention, however, the outlet of the recess is not formed in the receptacle, but may, for example, take place at a location of the hoist where no deposition of metallurgical dust is possible, such as at an underside of the hoist. Also, the proposed measuring arrangement is resistant to mechanical stress, since the force sensor is protected in the recess.

In the preferred embodiment, which will be explained further below, a piezo element is arranged in the region of the hook mouth such that it is loaded by the weight of the load carried by the hook only when the hook mouth holds the pin correctly. The use of a piezo element offers the advantage of a compact size, which allows the installation in standard hooks, such as the standardized according to DIN 15407 lamellar single hook for pig iron and Stahlgießpfannen, without having to deviate from the standard dimensions. Nevertheless, the piezoelectric element allows a reliable detection of the loads loading it.

By only the embodiment of the hook of a crane is explained in more detail below, the invention is not limited to this embodiment. The designs described below are also readily transferable to the hoist proposed by the invention in its claimed universality and are disclosed as training a hoist, the hook mouth is the recording of the hoist equate.

With proper threading of the pin in the hook mouth immediately after the initiation of the lifting operation and the associated initiation of the lifting force of

Pin in the mouth socket occurs an elastic deformation of the mouth shell. These

Deformation is detected by the sensor and detected by an evaluation. In case of improper threading the pin in the jaw, z. B. when lifting the load with the hook tips, so outside the jaw, this sensor signal is not generated due to the intended installation. At the

Deposition of the load it comes to the relief of the mouth shells, which likewise from the

Sensors detected and detected by the transmitter.

By the piezoelectric element according to the invention is arranged in the region of the hook mouth and not for example at the tip of the hook or in areas between the hook jaw and the suspension, it is ensured that the piezoelectric element indicates a load only when the pin transmitting the load is actually in the Hook mouth is located.

As a piezoelectric element is particularly suitable as a so-called quartz dowel. These

Sensors are suitable for measuring the forces in structures of machines, tools etc. indirectly via the strain.

In a preferred embodiment, the piezoelectric element is arranged in the region of the hook mouth. Here it can determine whether the hook mouth is loaded by a weight force. If this is the case, the pin is also in the hook mouth, so that the correct load bearing is detected correctly. Furthermore, the use of a single piezo element offers a cost advantage. According to an alternative embodiment, two piezo elements are arranged opposite each other outside of the hook mouth. For safety reasons, it may be desired, for example, to provide two piezo elements in the hook should one of the piezo elements fail. To the hook mouth in the area of its base not too much through recesses for receiving

To weaken piezoelectric elements, the piezoelectric elements outside of the hook base, for example, arranged on the edge side as the inductive sensors shown in DE 44 47 393 C1. Also in these positions, the piezo elements are loaded at least by a component of the weight transferred from the pin to the hook, so that they can reliably display the recording of the pin in the hook mouth even in this position. This is especially true when heavy loads are transported through the hook. This leads to a significant load on the piezo elements, which can be determined very reliably.

In a preferred embodiment, at least one piezoelectric element is in one

Recess of a jaw of the hook mouth arranged. Hooks, in particular the lamellar hooks used by lodge cranes often have a mouth protecting the hook's mouth. This jaw shell regularly has a wall thickness of more than 35 mm, so that it can accommodate, for example, conventionally cylindrical piezoelectric elements with a diameter of 10 mm, without a change in the outer shape of the mouth shell must be made. This also offers the advantage of being able to easily retrofit existing hooks, since in the simplest design, only the mouth socket needs to be replaced or machined, that is, for example, a recess has to be introduced into the jaw shell.

In a preferred embodiment, the recess receiving the piezoelectric element is oriented perpendicular to the radial direction of the jaw shell defined by the curvature of the jaw shell. This makes it possible to make the recess sideways, whereby the insertion and replacement of the

Piezoelectric element is simplified. In addition, the pin facing the inner surface of the jaw remains untouched, so that the known from DE 44 47 393 C1 covers known recesses of the inner surface of the jaw known problems can be avoided. In a further preferred embodiment, the recess from the bottom in the

Maulschale introduced. Thus, there are no openings, holes or the like in the area of the support surface of the jaw claws and, consequently, a deterioration of the sensors is excluded by the environmental conditions. In a preferred embodiment of the invention, measures are provided to lead cables that are necessary for connecting the piezoelectric element with an evaluation, protected. In a preferred embodiment, it is intended to avoid passing a cable along an outer surface of a component of the hook, since such a cable may snag and tear against surrounding elements or be crushed and damaged in contact with other elements. In a preferred embodiment, the mouth of the hook has an inner surface, which comes into contact with the pin of the load, and an adjacent to the inner surface, standing at an angle to the inner surface side surface in which a groove is provided, which receives from the piezoelectric element

Recess runs along the side surface. In this groove, a cable can be inserted, so that it is prevented that this cable, for example, rests against the outer surface of the side surface and is damaged there. Particularly preferably, this groove is closed by an attached cover, so that the groove and in particular the piezoelectric element receiving recess are protected.

In a preferred embodiment, the groove terminates at a cable recess in the jaw shell which extends from the side surface into the interior of the jaw shell. Depending on the construction of the hook, it has proven to be advantageous to remove the cable to be continued from the mouth shell in the area of the center (as seen in FIG

Width direction of the hook) lead out of the jaw shell of the mouth and from there continue, for example, through a through hole in the hook. This central guide of the cable ensures a particularly good protection of the cable.

Particularly preferably, the hook is designed as a lamellar hook of a huts crane, since the advantages achieved by the invention in huts cranes are particularly large.

In a preferred embodiment, a cable connected to the piezoelement is guided into a channel of a blind lamella. This has the advantage that the cable is protected from the house dust, the direct radiant heat and from mechanical damage.

In a preferred embodiment, an evaluation unit is connected to the piezoelectric element, which can determine the weight of the load received by the hook from the signal emitted by the piezoelectric element.

Alternatively, an evaluation unit can be provided, which converts the signal output by the piezoelectric element into a binary signal, wherein the one value is the Indicates loading of the piezo element with a weight above a certain threshold and the other value indicates the missing load.

The signal emitted by the piezoelectric element can be amplified by a charge amplifier provided in the region of the hook or on the hook. This is particularly preferred if one (the) evaluation unit itself is arranged at a considerable distance from the hook. For example, the evaluation unit may be arranged in the crane cab. Particularly preferred is the

Charge amplifier protected by a special housing temperature-protected or possibly even cooled. This facilitates the use of a charge amplifier in the area of the lifting of liquid molten metals and the radiated from them

Warmth.

The invention will be explained in more detail with reference to a drawing showing only one exemplary embodiment. It shows:

1 is a perspective view of a blind blade of a laminated hook according to the invention with a jaw shell inserted into the hook mouth,

Fig. 2 is an enlarged partial view of a detail of the blind blade and the jaw shell of FIG. 1 and

Fig. 3 shows another detail of the mouth of the lamellae hook according to the invention.

Fig. 1 shows the lower portion of a blind slat 1 of a composite of a plurality of juxtaposed slats lamellar hook, as standardized, for example, in DIN 15407. In the hook mouth of the slats a mouth 3 is arranged. The jaw cup 3 receives the pin 4 of a load received by the hook, for example, a pig iron and steel ladle.

The blind blade has a leading through the blind blade 1 and along the blind blade continuing recess 5, in which a cable 6 is performed. In the angle to the load-receiving inner surface of the jaw 3 standing side surface 7 of the mouth 3, a groove 8 is provided. As shown particularly clearly in FIG. 2, this recess extends along the side surface 7 of the jaw shell

3. It connects a recess 9 with a cable recess 10, which extends from the side surface into the interior of the mouth 3. This cable recess makes it possible, as can be clearly seen from the perspective view of FIG. 2, the cable 6 in the region of the center of the mouth 3 from the jaw shell 3 out and into the recess 5 to lead. In the recess 9, a piezoelectric element 20 is provided.

3 shows the arrangement of the piezoelectric element 20 in the recess 9. In addition, it can be seen in this figure that the blind plate 1 is arranged between other plates 11. In addition, Fig. 3 shows that the recess 9 and the groove 8 can be closed by a cover 12.

To receive a load, the hook is brought by the crane operator to the pin so that it is received by the hook mouth. Here comes the

When the load is correctly picked up, the pins should rest on the jaw. A simple

Lifting the hook causes the weight of the pin 2 to press the mouth cup.

This pressure is at least partially forwarded by the jaw shell to the piezoelectric element 20, which is thereby loaded and emits an electrical signal. The delivery of the electrical signal allows the crane operator to recognize that the load has been properly received in the hook jaw and not resting, for example, on the tip of the hook.

Fig. 1 further shows that in the mouth 3, three recesses 9 are provided, in which redundant piezoelectric elements are arranged to obtain a reliable signal on the correct recording of the load even in case of failure of a piezoelectric element.

Claims

claims:

1. hook of a crane with at least one piezoelectric element, which is arranged in the region of the hook mouth so that it is only loaded by the weight of a load carried by the hook when the pin is held in the hook mouth.

2. Hook according to claim 1, characterized in that the piezoelectric element is arranged in the region of the hook mouth.

3. hook according to claim 1, characterized by two piezo elements, which are arranged opposite each other outside of the immediate hook mouth.

4. hook according to one of claims 1 to 3, characterized in that at least one piezoelectric element is arranged in a recess of a jaw of the hook mouth.

5. hook according to claim 4, characterized in that the recess extends perpendicular to the defined by the curvature of the mouth shell radial direction of the mouth shell.

6. Hook according to one of claims 4 or 5, characterized by an inner surface of the mouth cup, which comes into contact with the pin of the load, and an inner surface adjacent, standing at an angle to the inner surface side surface in which a groove is provided which from the receiving the piezoelectric element recess starting along the side surface.

7. Hook according to claim 6, characterized in that the groove terminates at a cable recess in the mouth shell, which extends from the side surface into the interior of the mouth shell.

8. hook according to one of claims 1 to 7, characterized in that the hook is designed as a lamellar hook of a hut crane.

9. hook according to claim 8, characterized in that a cable connected to the piezoelectric element is guided in a channel of a blanking plate.

10. hoist with a receptacle for receiving the component of a load to which the load is raised, characterized by a self-introduced into the hoist, not open for receiving recess and one in the recess introduced force sensor, wherein the recess is guided in such a way and the force sensor is arranged in the recess, that the force sensor is arranged in the region of the receptacle by being loaded by the weight of a lifted load of the hoist only when the component of the load, where the load is lifted, is held in the receptacle.