JPH0418964B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a shearing device for shearing sections of predetermined length from an object to be cut, such as a billet or steel bar, for use as material for solid sections. A driven roller table is provided for transporting the workpiece through the working chamber of the shear, in which case the roller table is first raised and then lowered again to pass the workpiece through. This type is equipped with a holding device for fixing the workpiece to the corresponding support, a device for triggering the shear stroke, and a clamp-feeding device that is movable in the axial direction. relating to things.

BACKGROUND OF THE INVENTION Materials for solid sections are mainly produced by shearing steel bars or billets, since this is a cutting process without material loss. Also, the productivity is significantly greater than that of other cutting methods such as sawing, fusing, breaking, etc.

For cost reasons, billet,
That is, it is required to process the material from the pre-rolling line. However, if conventional shearing devices are used in this case, mass variations of up to approximately ±4% occur. Such variations can be caused by incorrectly formed parts, excessive tool wear,
This can lead to disturbances such as overloading of tools and machines, so it is of course necessary to prevent mass fluctuations from occurring. The volume variations of the cut sections that occur during this shearing are caused, on the one hand, by large manufacturing tolerances of the semi-finished product (billet) and, on the other hand, by the influence of the machines and tools.

When adjusting the length of the section to be sheared, it is known to transport the workpiece through a shear by means of a roller table to a stop on the delivery side of the shear, in which case the driven rollers of the roller table This causes a shift. In this case, in order to be able to feed the object to be cut, generally
The roller level of the roller table is raised until the workpiece runs frictionlessly between the hold-down device and the corresponding bearing or the lower knife into the working chamber of the shear. A shearing stroke is then triggered by a contact connection between the stopper and the object to be cut. In this case, before shearing, a hold-down device is activated to lower the roller table, thereby protecting it against the impacts of the material to be cut that occur during the shearing process. Furthermore, during the cutting the stopper can be reversed, thereby preventing the sheared section from being clamped between the stopper and the knife. In this case, when the roller table is lowered, it is unavoidable that the object to be cut is also displaced in its axial direction.

In other known shearing devices, therefore, the workpiece to be cut is reliably and forcibly held and guided when approaching the stop, so that the workpiece can be guided, for example, when the roller table is lowered. Disturbances caused by positional changes, the inherent weight of the object to be cut, the coefficient of friction between the driven roller and the object to be cut, etc. are reliably eliminated. In this case, also due to the perfect guidance of the material to be cut when approaching the stopper,
It has become possible to reduce the mass error clearly to less than ±0.5%, which provides the prerequisites for accurate and burr-free forging. As a result, dimensional variations in the member can be kept to a very small level, and it is therefore possible to manufacture shear planes with high dimensional accuracy without post-work. Also, compared to forging with burrs, weight savings can be achieved in forging without burr gaps. This results in high durable strength for forged parts.

However, this known shearing device has the following drawbacks. That is, during shearing, plastic deformation occurs on both sides of the shear plane of the workpiece due to the upright knife, and this deformation is very obvious at the ends of the block and at the opposite ends of the workpiece. This plastic deformation occurs not only in the transverse or radial direction of the workpiece, but also in the axial direction of the material, which results in an increase in the length of the workpiece. That is, during shearing, the block and the workpiece move in opposite directions in the axial direction. Furthermore, this plastic deformation is not constant and largely depends on the material and strength. Since the material to be cut is a heat-treated material sent from a pre-rolling line, various structural states and therefore strengths are formed inside the material. As a result, different magnitudes of plastic deformation occur in the vicinity of the shear knife, which has a disadvantageous effect on the shear division being carried out with as uniform a mass as possible.

OBJECT OF THE INVENTION It is therefore an object of the invention to improve the construction of a clamping and feeding device such that it does not lead to the disadvantageous plastic deformations that conventionally occur in sheared sections.

Means for Solving the Problem In order to solve this problem, the configuration of the present invention includes:
In a shearing device of the type mentioned at the outset, the clamping and feeding device has a continuously adjustable stroke limiting device, by means of which the length of the cutting section can be adjusted and the length of the cut section can be adjusted. A stationary clamping device for gripping the workpiece is mounted on the shear, the clamping jaw of the clamping device being axially loaded by a return spring.

Effects of the Invention With this embodiment, the influence of different plastic deformations occurring during shearing can be eliminated when adjusting the shear section length. These different plastic deformations are
In the fixation of the workpiece or the end of the workpiece, a corresponding return movement occurs, which leads to a relatively large error in the length of each section;
The mass uniformity of each sheared block is improved by the effect of its plastic deformation. The workpiece fed using the clamp-feeding device is held firmly in its shearing position. The axial movement of the clamping device that occurs during shearing is then absorbed by the return spring. The shear section length is also adjusted by an adjustable stroke limiter.

The return spring has two functions. On the one hand, the return spring thus compensates the workpiece in the axial direction during shearing and can then bring it back to the starting position. On the other hand, the return spring also enables the stationary clamping device to clamp the workpiece without play in the starting position.

Embodiment In the shearing device shown in the drawings, a drive cylinder 3 and a lower knife holder 4 holding a lower shear knife 5 are arranged in the shear 1 between two mounts 2. In this case, these parts form one immovable structural unit. The knife holder 4 also serves as a corresponding support for the hold-down device 9. The drive cylinder 3 has a drive piston 6 which is provided with an upper knife holder 7 for holding an upper knife 8 . A further drive piston 6a for the hold-down device 9 is arranged in the drive piston 6. A counter-holding device 4a is arranged on the lower knife holder 4, which is designed as a cylinder in its lower part and cooperates with a metering piston 4b.

As can be seen from the drawing, a clamp/feeding device 14 is disposed on the inlet side of the shear 1, and this clamping/feeding device includes a clamp jaw 15, which grips the object to be cut, such as a billet or a steel bar, in between.
It has 16. Both clamps 15, 16
is brought into a clamping position towards the workpiece 11 by means of a piston-cylinder unit 17 connected to a rod 18. In this case, the clamping jaws 15, 16 form a clamping device, which clamps the workpiece 11 with a constant force. Further, reference numeral 20 indicates a column for the clamp-feeding device 14.

The shear 1 shown does not have a stop device for the front end of the workpiece 11. Instead, the clamping and feeding device has an additional function.
This clamping and feeding device 14 consists first of all of an additional clamping device 30 which is in principle fixedly arranged.
have. This clamping device 30 can be mounted on a shaft 31 . The stationary clamping device 30 has clamping jaws 32 and 33, both of which are under the action of return springs 34, 35. Each return spring has a corresponding bearing in a U-shaped element 36, which is part of a holder 37 for an axially movable clamping and feeding device 14. Clamping device 30 mounted in a fixed position
The actuation of each clamping jaw 32, 33 is preferably carried out hydraulically or pneumatically.

The axially movable clamping and feeding device 14 preferably has a continuously adjustable stroke limiting device 39 with an adjustment motor 40, which device 39
The length of the cut section to be sheared from the workpiece 11 is adjusted by this. Each clamp jaw 15, 16 arranged in the clamp/feeding device 14
Also advantageously, blade springs 41, 42 are provided to enable play-free capture of the workpiece in the starting position.

Each return spring 34, 35 of the clamping device 30, which is arranged in a fixed position, releases the workpiece 1 during shearing.
It functions to absorb the axial movement that occurs in 1. As a result, the material to be cut can be compensated in the axial direction during shearing, so that it can again assume its original position. Various plastic deformations that may occur in the workpiece and the cutting section only result in a corresponding return movement of the clamping device 30. Similarly, the return springs 41 and 42 of the clamp-feeding device 14
This also serves to enable play-free acquisition of the workpiece in the starting position.

After pulling back the movable knife 8, the respective return spring pushes the workpiece forward again to the predetermined starting position. Only after this return movement has taken place, the axially movable clamping and feeding device 14 is closed;
The clamping device 30 is then opened and the movable clamping and feeding device 14 moves with the workpiece 11 to drive it into the predetermined shearing position. After this, the stationary clamping device 30 is closed and the movable clamping and feeding device 14 is opened and travels back to its predetermined starting position.

[Brief explanation of drawings]

The drawing is a side view schematically showing an embodiment of a shearing device according to the invention. 1... Shear, 2... Frame, 3... Drive cylinder,
4, 7...Knife holder, 4a...Compatible holding device, 4
b... Piston, 5, 8... Knife, 6, 6a... Drive piston, 9... Holding device, 11... Object to be cut, 1
4... Clamp and feed device, 15, 16, 32, 3
3... Clamp jaw, 17... Piston cylinder unit, 18... Rod, 20... Strut, 21... Roller table, 22... Roller, 23... Lifting cylinder, 24... Shock absorber, 25... Piston cylinder unit, 26... Piston, 27... Piston rod, 2
8...roller, 30...clamp device, 31...shaft, 3
4, 35, 41, 42... Return spring, 36... U-shaped member, 37... Holder, 39... Stroke limiting device, 40
...adjustment motor.

Claims (1)

[Scope of Claims] 1. A shearing device for shearing sections of a predetermined length from an object to be cut, such as a billet or a steel bar, for use as a raw material for a solid section, the device comprising: A driven roller table is provided for conveying the material to be cut, in which case the roller table is first raised and then lowered again in order to pass the material to be cut, and a corresponding bearing is provided. In a type that is provided with a holding device for fixing the workpiece to be cut, a device for triggering the shear stroke, and a clamp-cum-feeding device movable in the axial direction,
The clamping and feeding device 14 has a continuously adjustable stroke limiting device 39, by means of which the length of the cutting section can be adjusted, and a fixed position clamp for gripping the workpiece. A device 30 is mounted on the shear, the clamping jaws 32, 33 of the clamping device being axially moved by return springs 34,
35. 2. Shearing device according to claim 1, in which the clamping device 30 is pivotably suspended on a shaft 31. 3 Clamp Jyo 1 of clamp and feed device 14
3. Shearing device according to claim 1 or 2, wherein 5, 16 are under the action of their own return springs 41, 42. 4 Clamp jaws 32, 3 of clamp device 30
Claims 1 to 3, characterized in that the corresponding receptacles of the return springs 34, 35 for 3 are formed by the holders 36, 37 of the clamping and feeding device 14. shearing device.