DE2058858A1 - Hoist tongs - Google Patents

Description

Patent attorneys Dipl.-Ing. F. Weickmann,

Dipl.-Ing. H.Weickmann, Dipl. -Phys.Dr. K. FiNCKE Dipl.-Ing. F. A. Weickmann, Dipl.-Chem. B. Huber

8 MUNICH 86, POST BOX 860 820

MOHLSTRASSE 22, NUMBER 48 39 21/22

<983921/22>

Gn / Ba

British Steel Corporation

33 G-rosvenor Place
London, SW 1, (England)

Hoist tongs

The invention relates to a hoist tongs with a pair of arms articulated to one another, which have a pair of arms on a workpiece form attacking cheeks.

Such hoist tongs are used for lifting and transporting of relatively heavy workpieces or goods, for example of steel blocks in steelworks, and are used often operated remotely for security reasons. You must maintain an open position of the jaws engaging the workpiece can and set up for quick and easy closing after arranging in the exact position to the workpiece · In addition, the jaws must be easy and quick to open to allow the workpiece to be opened once it has reached its destination release and must be in the open position for the purpose of implementation remain open during a subsequent lifting operation.

It is known that such conditions can be met by a so-called

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tes locking mechanism, which is controlled by a rope that is independent of the hoist or crane rope. Even though this device work satisfactorily even under difficult operating conditions, such as for example with soot occur in the steel industry, they require an additional equipment of the crane not only with an additional one and independent control mechanism for the locking gear, but also with an additional manual control device that can be operated in an already limited space got to.

Efforts have therefore been made to reduce the cost and operational difficulties of achieving the above Requirements for a hoist tongs of the type described above to reduce that the hoist tongs are to be provided with automatically locking and releasing devices on the jaws on the arms of the Responding upward thrust acting on the jaws.

Hoist pliers in which these facilities have locking mechanisms have been proposed in large numbers, but these are too sensitive to blows as they occur, for example, and etc. during pivoting against the sides of a deep furnace are therefore not acceptable because of their high w costs.

The invention is based on the object of providing a lifting tool tong of the type described above, in which the the disadvantages listed above are eliminated. The solution is that the hoist tongs consist of a pair of pivotable arms articulated to one another for forming on a workpiece attacking jaws and a locking element is connected to these arms, which in a first position ^

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± in which the closing of the jaws is prevented, and in a second position in which the jaws are closed can, depending on the opening movements of the jaws is movable.

In a preferred embodiment it is provided that the locking element on one of the arms for the plant one with this cooperating guide element of the other Arm is pivoted.

One embodiment of the hoist tongs according to the invention provides that the locking element is pivotably mounted on an arm is and an opening for receiving the guide element of the other arm, wherein the opening is formed so that the guide element as a result of the continuous opening movements the jaws at least over part of the opening forming and slides.

The opening is preferably designed so that the opening has a blocking area in which the guide element is held against a corresponding closing movement of the jaws is, wherein the blocking area is a receptacle for the guide element has, in its movement in relation to the locking element in the corresponding to the closing movement of the jaws Direction is prevented. Alternatively, the resistance to this movement can be achieved in that the blocking area has an additional locking element, which through the guide element is offset, with part of the offset corresponding to the opening of the jaws and which then corresponds to one of the Opening of the jaws corresponding movement of the guide element prevented.

In a further embodiment of the invention it is provided that the first and the second position of the locking element two difficult

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Include point displacements of the same, for example, it is provided that the locking element during his Relative movement to the guide element on the other arm can be moved into a center of gravity position, which is the closing of the Jaws corresponds, and only offset from this position by a relative movement corresponding to the opening of the jaws can be. The guide element is pressed against the area of the opening in a center of gravity position, which has the receptacle or the additional locking element so that the constant securing can take place. In response to opening the jaw, the locking element is then swiveled into the second division of the center of gravity, in which the guide element * ment is pressed against the opposite wall area, whereby a re-entry into the receptacle during the further The course of the work process is prevented.

It is also provided that the locking element between the focus positions according to the cam control principle with respect to of the guide element and the wall of the opening are movable is. Securing in the focus positions can be effected solely by gravity, or with the support of a so-called snap spring, which is more suitable Way is to be arranged in the locking mechanism.

fe The guide element preferably has a role to to reduce the frictional resistance occurring during the relative rotation on the wall of the opening.

The arms of the hoist tongs are preferably spaced from one another mutually arranged plates connected by webs are formed. In this case, the locking mechanism between the Plates be arranged to give this protection against impact and shock. The locking mechanism can be in any

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Area of each of the pairs of arms to be arranged, the cooperate to open and close the jaws.

In the accompanying drawings, an embodiment of the hoist tongs according to the invention is shown schematically, which is explained in detail with reference to the description below. The drawings show:

Fig. 1 is a perspective view of the invention Lifting pliers;

2 shows a section through the elongated hoist tongs, wherein the claws abut a piglet;

FIG. 3 shows a side view of the lifting forceps according to FIG. 1 in section and in a first operating position} and

FIG. H shows a partial section through the locking mechanism recognizable in FIG. 2 in a second operating position.

The hoist tongs shown in the drawings have two arms 2 and h according to FIG. The arms 2 and 4 are pivotably articulated to one another at a point located essentially between their ends, whereby jaws that can be placed on a workpiece are formed at the lower ends and lowering it for treatment, for example in a soaking oven - the jaws are provided with points 8 which press into the sides of the steel block and reduce the risk of accidental release during the lifting process.

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Two support arms 9 and 10 are articulated with their lower ends mitteis bolts 12 and λΗ with the arms 2 and k , while their upper ends are hinged to a bracket 16, by means of which the hoist tongs on a hook or a loop of a suitable Hoist can be attached. In operation, the lifting of the hoist tongs causes the jaws 8 to close and thus to grip the workpiece between them.

A locking mechanism is for securing the jaws in their open position for picking up the workpiece and then automatic release of the jaws for the purpose of closing the same provided.

This locking mechanism has a locking element 20 which is arranged by means of a pivot pin 21 on the arm k and ends at its upper end in a substantially straight-line part 2k which, although it is shown open in the drawing, can also be closed. A guide element 26 in the form of a fixed pin or a roller on the arm 2 is arranged in the opening 22 of the locking element 20 and slides cyclically on the wall of the same.

When the jaws according to FIG. 2 are in contact with a workpiece, or in some other way in their closed position, the guide element 2ö is at the upper end of the wall part 2k. The length of the wall part 2k is dimensioned so that any deflection of the guide element 26 over each possible degree of closing of the Eakken supported by a ^{stop r} j6 attached to the arm K and limiting the pivoting of the arm 2; will.

When the hoist tongs are lowered onto a support surface,

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an upward thrust acts directly or indirectly from the workpiece on the arms 2 and 4 and causes the jaws to open and thus a downward movement of the guide element 20 on the warid part 2k up to the bend 30

The center of gravity of the locking element 20 is arranged so that the equilibrium ratio in the state described above is an automatic pivoting of the locking element 20, with further downward movement, the stop 26 causes relative to the opening 22 and thereby with the receptacle 32 in the Wall of the opening 22 rests against the guide element 26 (see Figure 3) · The shape of the receptacle 32 is such that a closure the jaws 8 as long as the weight of the hoist tongs alone is worn by the bracket 16 is prevented.

A subsequent and independent upward thrust against the arms 2 and k when the hoist tongs are further lowered onto the support surface opens the jaws for the purpose of releasing the workpiece, if it was previously held on the wall of the opening 22 to its lowest point 3 ^ (see Figure k); further opening is prevented by a stop 28 when this point is reached.

At this stage, the locking element 20 has reached its second equilibrium position, through the action of the guide element 26 on the wall of the opening 22, so that when the jaws are closed as a result of lifting the hoist tongs, the wall part kO of the wall of the opening 22 against the Guide element 26 is forced. As a result, the guide element 26 runs to the upper wall part Zh until the end of the complete cycle without reaching the receptacle 32 again.

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The hoist tongs are thus ready for further work depending on further forces acting on the arms 2 and k.

In use, a crane that lifts the automatic hoist tongs according to the invention is often operated from a control stand that is considerably high above the ground. In order to enable the operator to monitor the degree of opening of the jaws, in particular to recognize whether the jaws are open enough to allow the locking mechanism to become effective, a suitable signaling device can be provided on the k hoist tongs. This can be of any known type, for example a follow-up pointer, which can simply consist of an extension of the straight part of the Yand part Zk of the locking element 20.

It is evident that this was caused by the receptacle 32 automatic locking mechanism also in other ways, for example can be achieved by a further pivotable locking element. A so-called snap spring can also be provided which additionally or independently secures the locking element in its eccentric positions by spring force Furthermore, the lifting tool tongs described, which are equipped with jaws in the form of tips, can open any other type of jaws on-P ways that are suitable for attacking other workpieces, such as barrels, planks, sacks that are not related to the metal industry in association with.

For reasons of safety, the crane hook is equipped with devices that allow the hoist tongs to loosen, even if it is excessive Lowering, prevented.

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Claims (12)

Claims ebezeug tongs with a pair of attached to each other Arms which form a pair of jaws engaging a workpiece, characterized in that on the arms (2, 4) a locking mechanism with a locking element (20) is arranged which is in a first position in which the closing of the jaws (8) is prevented and in a second position in which the jaws (8) can be closed, can be moved as a function of the opening movements of the jaws (8). 2. Hoist pliers according to claim 1, characterized in that the locking element (20 ) is pivotably mounted on one of the arms (4) for contact with a guide element {2.6) of the other arm (2) cooperating with this. 3 · Hoist tongs according to claim 1 and 2, characterized in that the locking element (20 ^ is pivotably mounted on one arm (h) and has an opening (22) for receiving the guide element (26) of the other arm (2) wherein the opening (22) is designed in such a way that the guide element (26) slides at least over part of the wall forming the opening (22) as a result of the continuous opening movements of the jaws (8). · Lifting tool tongs according to claim 3, characterized in that the opening (22) has a blocking area in which the guide element (26) is held against a corresponding closing movement of the jaws (8). 5 · Hoist tongs according to claim 4, characterized in that that the restricted area has a receptacle (32) for the guide 109824/1234 element (26), in which its movement in relation to the locking element (26) in the closing movement of the Baking (8) corresponding direction is prevented. 6. Hoist pliers according to claim 4, characterized in that that the blocking area has an additional blocking element which is offset by the guide element (26), wherein part of the offset corresponds to the opening of the jaws (8) and which then corresponds to one of the opening of the Baking prevents corresponding movement of the guide element (26). 7 · Hoist tongs according to one or more of claims 1 to 6, characterized in that the first and the second position of the locking element (20) have two shifts in the center of gravity include the same. 8. Hoist pliers according to claim 7 »characterized in that that the locking element (20) during its relative movement to the guide element (26) on the other arm (2) in a center of gravity position is movable, which corresponds to the closing of the jaws (8), and from this position only by one of the Opening the jaws (8) can be offset corresponding relative movement. 9 »Hoist tongs according to claim 3 to 8, characterized in that that the locking element (20) between the focal positions according to the cam control principle beaüglich des Guide element (26) and the wall of the opening (22) is movable. 10. Hoist pliers according to claims 7 to 9, characterized in that that the locking element (2θ) in the center of gravity 1 0 9 8 2 Λ / 1 234 lungs are secured by a snap spring. 11. Hoist pliers according to one of claims 1 to 9, characterized characterized in that the locking element (2θ) in his Center of gravity is held by gravity, for which it is stored under its center of gravity. 12. Hoist pliers according to claims 3 to 11, characterized in that that the guide element (26) has a roller for the purpose of smoother rotation on the wall of the opening (22). 13 · Hoist tongs according to claims 1 to 12, characterized in that the arms (2, A) are each provided with two identical, arranged at a distance from one another and connected by webs (5) Plates are formed, between which the locking mechanism (20) is arranged. 109824/1234