Patent ID: 7559220

Claim:
Bar speed changing device, to change a first speed at which bars of a given length travel along an axis (X) thereof after leaving a rolling train up to a second speed at which said bars are fed, comprising: at least one first pair of rotating means, having their respective axes of rotation parallel to one another, so as to create a support for the bars, at least one second pair of rotating means, having their respective axes of rotation parallel to one another, arranged at a predefined distance from the first pair of rotating means, in order to define an intermediate passage for the bars, in which the bars can slide axially, motors that make the rotating means of the first and second pairs rotate around their respective axes at a controlled speed during bar feed, means for controlling the speed of the rotating means to keep the rotating means turning at the second feeding speed and actuator means comprising a pneumatic cylinder of the push type for bringing the rotating means of the second pair closer to the first pair, so that the bar can be gripped between the rotating means during the movement to generate friction between the rotating means and the bars, and a hydraulic cylinder of the pull type for moving the rotating means of the second pair away from the first pair.