Drive shaft for transmitting motion to a roll

Abstract

A drive shaft for transmitting motion to a roll of a tube rolling stand comprising a telescopic body, a slide and a support base. The telescopic body is fixed by one end with a cardan joint to the drive shaft of the gearbox, and on the other end has a fitting for attaching the roll. The slide is hinged to the support base and may rotate under the bias of a jack to either engage or release the telescopic body. A snap-action locking device, contained within the telescopic body, comprises a cylinder, on which two rocker arms are hinged, and a spring which spreads the rocker arms making the two teeth fit into two holes in the wall of the cylinder, when the drive shaft is at its maximum working length. The carriage has two pistons to work on the two rocker arms thus freeing the locking device and allowing the telescopic sliding of the cylinder in the cylinder and the downward rotation of the drive shaft.

Description

FIELD OF THE INVENTION[0001]The present invention relates to a drive shaft for transmitting motion from a motor or gearbox to a roll, in particular for rolling tubes.STATE OF THE ART[0002]A very common technique for rolling tubes without welding operated with a mandrel is nowadays carried out on a rolling mill comprising a sequence of rolling stands with two rolls or three rolls. The rotation axes of the rolls of each rolling stand are mutually coplanar and lie on a plane orthogonal to the rolling axis.[0003]Typically in two-roll rolling stands, the rolls of one stand are arranged offset by 90° with respect to the previous adjacent rolling stands, whereas in three-roll rolling stands the rolls of a rolling stand are usually offset by a 60° angle with respect to the adjacent rolling stands in the direction of the rolling line. In three-roll rolling stands of the latter type, during rolling, the rolls of each rolling stand receive the motion generated by respective gearbox by means of...

AI Technical Summary

Benefits of technology

The present invention provides a rotary motion drive shaft that is lightweight and easy to handle. It allows for a long shortening strokes during the release operation. This drive shaft also simplifies the maintenance operation of the rolling stand as it reduces the number of steps needed to extract the rolls. The drive shaft is designed to connect the slow shaft of a gearbox to a roll, and it allows for a lower number of operations. The drive shaft support slide moves from a stand-by position to a hooked position to align the two hydraulic cylinders with the spring of the snap-action locking mechanism. The drive shaft is then rotated downwards to release the snap-action locking mechanism. The telescopically sliding cylinder also releases the snap-action locking mechanism by exerting a compression force on the spring.

Problems solved by technology

The way in which the drive shaft is assembled and disassembled is not disclosed but generally the detachment also requires moving the gearbox and the motor fitted on the slide, which is a rather laborious operation.

A disadvantage of this solution is the need to provide a high number of Belleville washers in the drive shaft, which increases the overall weight of the drive shaft.

Furthermore, this solution does not offer a very favorable shortening ratio of the drive shaft.

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