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.

1 . A device for transmitting the motion to a roll of a rolling stand comprising:
 a telescopic drive shaft having two telescopic members sliding within each other by a predefined sliding stroke,   a snap-action locking mechanism for locking the two telescopic members to a predefined working length,   an elastic device exerting a preloading force axially directed along the two telescopic members, in the end part of the sliding stroke,   a drive shaft support incorporating a drive shaft extending and shortening device and a release mechanism, adapted to be remotely controlled, for releasing the snap-action locking mechanism.   
     
     
         2 . A device according to  claim 1 , wherein one of said two telescopic members has an inner cavity and a first end incorporating a fitting device adapted to be attached to the roll, and the other one of the two telescopic members is coaxial to the first cylinder, has a first end housed within the inner cavity of the first cylinder, has a second end incorporating a universal or cardan joint adapted to be fitted onto a motion transmission shaft so as to allow an angular rotation of the drive shaft with respect to the rolling stand. 
     
     
         3 . A device according to  claim 2 , wherein the drive shaft support comprises:
 a slide having at least one or more hinges at a first end defining a first rotation axis, so as to allow an angular rotation of the slide with respect to the rolling stand about the first rotation axis, and   a carriage longitudinally sliding along said slide, incorporating disengageable attaching means to the first cylinder, first actuating means adapted to rotate the slide about the one or more hinges, and wherein the drive shaft extending and shortening device ( 60 ) is adapted to slide the carriage with respect to the slide ( 50 ).   
     
     
         4 . A device according to  claim 3 , wherein the first rotation axis is arranged parallel to the rolling axis when mounted on the rolling stand. 
     
     
         5 . A device according to  claim 4 , wherein the universal or cardan joint has the junction center of the drive shaft and of the motion transmission axis coinciding with the first rotation axis of the one or more hinges. 
     
     
         6 . A device according to  claim 5 , wherein the attaching means are provided with a groove made on the carriage and a peripheral ring integrally fixed to the surface of the first cylinder. 
     
     
         7 . A device according to  claim 6 , comprising a support base whereon the one or more hinges are attached. 
     
     
         8 . A device according to  claim 7 , wherein the device for releasing the snap-action locking mechanism comprises two hydraulic pistons adapted to exert a compression force on extremities of a spring which keeps the snap-action locking mechanism locked. 
     
     
         9 . A method for removing a device according to  claim 1  from a rolling stand, comprising the following steps:
 rotating the drive shaft support slide upwards about the first axis so as to move from a stand-by position thereof, angularly away from the drive shaft, to a hooked position with the drive shaft, with the carriage arranged in an axial position whereby the groove fits onto the ring, 
 rotating the drive shaft about the longitudinal axis thereof so as to align the two hydraulic cylinders with the axis of the spring of the snap-action locking mechanism, shifting the first cylinder by means of the carriage by a short stretch directed in an opposite direction with respect to arrow F 2 , sufficient for opposing the force of the elastic device for releasing the snap-action locking mechanism from the fit, 
 exerting a compression force on the spring by means of the two hydraulic cylinders, thus releasing the snap-action locking mechanism, 
 telescopically sliding the first cylinder in the direction of arrow F 2  by a predetermined length by means of the carriage, 
 rotating the drive shaft downwards about the first rotation axis. 
 
     
     
         10 . A rolling stand for rolling metal members comprising a device according to  claim 1 .