Abstract: The present invention is directed to an overhead travelling crane for lifting and transporting a heavy load over an obstacle including a carriage with front and rear wheels mounted on independent axles for movement along respective rails. The rails engaged by the rear wheels are horizontal while those engaged by the front wheels each have a first section sloping upwardly from a starting point at one side of the obstacle, a central horizontal section extending over the obstacle and a final downwardly-sloping section. In use, a load is engaged with a support member adjacent the front end of the carriage and the carriage is driven along the rails to transport the load, the load being raised as the front wheels climb the first sections of their rails and being lowered as the front wheels descend the final sections.

Abstract: Rolling mills for rolling seamless tubes from axially pierced blanks or billets using a restrained mandrel have suffered from a high dead time in the oprating cycle due to the necessity of returning a mandrel-restraining cross-piece or other member from its final position back to its initial position through the roll stands before beginning the positioning of the next billet to be rolled. This invention overcomes the above-mentioned problem by providing an elongate axially extending recess in the mandre-restraining crosspiece which allows the next billet to be positioned before the end of the preceding rolling operation. The mandrel-restraining crosspiece is ready to be connected up immediately to the next billet when the mandrel-restraining crosspiece has returned to its initial working position, by enabling the crosspiece to pass over the billet which goes through the recess.

Abstract: The present invention is directed to a device for inserting and thrusting a bar into a double rolling pressure piercing mill (PPM) machine comprises a drum-shaped bedplate coaxially keyed to a motor-driven shaft having its axis of rotation parallel to the PPM's rolling axis, a first and a second thrust means on the drum-shaped bedplate having acting lines (R R.sub.1) parallel to the PPM's rolling axis and circumferentially spaced from each other by a predetermined center angle, a motor for angularly moving the drum-shaped bedplate from a position in which the line R coincides with the rolling axis to a second position in which the line R.sub.1 coincides with said rolling axis and vice-versa.

Abstract: A device whereby a square bar is inserted and pushed into a press-piercing mill (PPM), the bar being disposed along the rolling and drilling axis of the mill, the apparatus being characterized in that it comprises:a first thrust means (20) having a direction of action (R.sub.1) and thrusting the bar (7) at a speed set for introducing the bar into the (PPM);a second thrust means (14) having a direction of action (R) and thrusting the bar (7) at a speed set for rolling and simultaneously drilling the bar (7) in the (PPM), andan actuator (34) for simultaneously moving the first and second thrust means (20, 14) from a position in which the direction of action (R.sub.1) coincides with PPM rolling axis (A) and the direction of action (R) is at a distance from the rolling axis (A) to a position in which the direction of action (R.sub.1) is at a distance from the rolling axis (A) and the direction of action (R) coincides with the axis (A) and vice versa.

Abstract: A device for controlling the speed of a mandrel in a continuous retained-mandrel rolling mill, such device comprising a rod having a double rack provided at one end with a means for removably securing an end of a mandrel and a number of pinions engaging the rack on the rod, each pinion being driven in rotation by a corresponding motor-driven shaft which, via respective clutches is connected to a motor and speed-reducing group provided with a brake for each motor-driven shaft. Further, the device includes a second set of pinions engaging the rack on the rod, each pinion being driven in rotation by a corresponding motor and speed-reducing group provided with a brake.