Patent Application
20130145914
The invention concerns a crank shear, especially for cutting rolled strip, which comprises two pairs of blades that can be mounted on blade holders, wherein the blade holders are supported opposite each other in a vertical plane in a pair of eccentric drive shafts and are pivoted on torque supporting levers in double-joint mechanisms in interaction with hydraulic control units that act on these double-joint mechanisms.
Widely used crank shears have the disadvantage that they have only one pair of blades, usually with a convex cutting edge. Rotary shears used for the same application are known from the prior art, which have two pairs of blades, each of which has one convex and one concave cutting edge. In this regard, to achieve the ability to have a greater influence on the strip ends, the leading end of the strip is cut, for example, with a convex blade cutting edge, while the tail end of the strip is cut with a concave blade cutting edge.
The document EP 0 075 448 describes a crank shear with two pairs of blades which are supported opposite each other in a vertical plane in a pair of eccentric drive shafts and are pivoted on torque supporting levers in double-joint mechanisms with at least one hydraulic control unit that acts on these double-joint mechanisms.
The previously known shear for cutting metal strip has two blade holders, which can be rotated relative to each other, so that the blades can be alternately brought by their two blade holders into cutting positions with the metal strip. Each blade holder has a mounting for two blades and can be moved between two positions, in which the corresponding blades can each be brought into an operating position.
With this arrangement, one pair of blades at a time can be sharpened, while the other pair is used for cutting, and then both pairs can possibly be exchanged for one another.
A disadvantage of the previously known crank shear with two pairs of blades is the passage position of extremely small width that can be occupied between the pairs of blades, which, for example, during the passage of an upwardly bent leading end of a strip, can result in collision with the shear. A disruption of this type costs operating time and material. Another difficulty with the previously known shear is that the blades cannot be mounted in the blade holders with the provenly effective blade guard clamp.
The document EP 0 075 448 A discloses a crank shear with two pairs of blades that can be mounted on blade holders. The pairs of blades can be brought into a cutting position or into a maintenance position by means of a double-joint mechanism. The cutting position or the maintenance position is set by means of actuating cylinders that act on the corresponding double-joint mechanism. This document does not address the question of how a safe position for the passage of upwardly bent rolled strip can be reached.
Proceeding on the basis of the aforementioned prior art, the objective of the invention is to specify a design of the crank shear with two pairs of blades that avoids the aforementioned problems and disadvantages and, in particular, allows a significantly wider passage position for the rolled strip and also allows the use of the proven blade guard clamp without any difficulties.
In this regard, one embodiment of the invention provides that in a spread position of the torque supporting levers of approximately 90° and at the shortest separation of the eccentric shafts and a running direction of the rolled strip towards the supporting levers, a position of the pair of blades is reached for the cropping cut at the leading end of the strip, in which the hydraulic control unit on the upper supporting lever of the double-joint mechanism is fully extended, and the hydraulic control unit on the lower supporting lever of the double-joint mechanism is fully retracted.
In addition, the invention provides that in an approximately horizontal parallel position of the torque supporting levers opposite the running direction of the rolled strip and at the shortest separation of the eccentric shafts, and with the upper and lower double-joint mechanism extended approximately linearly, a position of the rear pair of blades for cutting the tail end of the strip is reached, in which the hydraulic control unit on the upper supporting lever of the double-joint mechanism is fully retracted, and the control unit on the lower supporting lever of the double-joint mechanism is fully extended.
The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of the disclosure. For a better understanding of the invention, its operating advantages, specific objects attained by its use, reference should be had to the drawings and descriptive matter in which there are illustrated and described preferred embodiments of the invention.
In the drawing:
The blade holders 1, 2 form axially parallel pairs of bearing surfaces 16 to 18 for the pairs of blades 3, 4 on approximately radial projections 13 to 15, with the upper pair of blades 3 arranged on inner, oppositely oriented bearing surfaces 16, 17 of a curved recess 20 of the upper blade holder 1, and with the lower pair of blades 4 arranged on the outer bearing surfaces 18 of a relatively narrow projection 15 oriented towards the recess 20.
In a spread position of the torque supporting levers 7, 8 of approximately 90° and at the shortest separation D of the eccentric shafts 5, 6 and a running direction 21 of the rolled strip 22, the crank shear has reached a position of the pair of blades 3 for the cropping cut at the leading end 23 of the strip. In this position, the hydraulic control unit 11 on the upper supporting lever 7 of the double-joint mechanism 9 is fully extended to spread the supporting lever 7, and the control unit 12 on the lower supporting lever 8 of the double-joint mechanism 10 is fully retracted. Reference number 19 identifies the roller table for conveying the rolled strip 22.
Finally,
While specific embodiments of the invention have been shown and described in detail to illustrate the inventive principles, it will be understood that the invention may be embodied otherwise without departing from such principles.
| Number | Date | Country | Kind |
|---|---|---|---|
| 102 58 887.2 | Dec 2002 | DE | national |
The present application is a Continuation Application of U.S. patent application Ser. No. 10/538,970, filed Jun. 14, 2005, which is a 371 of International application PCT/EP2003/014225, filed Dec. 15, 2003, which claims priority of DE 102 58 887.2, filed Dec. 17, 2002, the priority of these applications is hereby claimed and these applications are incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 10538970 | Jun 2005 | US |
| Child | 13764475 | US |
