TWISTING MACHINE FOR POLYGONAL CROSS-SECTION BARS TWISTING MACHINE FOR POLYGONAL CROSS-SECTION BARS

摘要

A twisting machine for polygonal cross-section bars having an independent jaw chuck (3) fitted on a mandrel (2) and a counteracting support (4) slidable on a prismatic guide (5), which is firmly connected to the machine and parallel to said mandrel (2) is disclosed. The jaw chuck (3) comprises mutually co-operating means of rotary connection between said mandrel (2) and said chuck (3), in the form of a groove for ball re-circulating and means of mutually engagement, such as an abutment projection (20) diametrally projecting from and integral with the mandrel (2) and a longitudinal pin (9) connected to the chuck (3), which are adapted to drive into rotation the chuck (3) by means of the mandrel (2), after a free rotation of the mandrel along an arc with an angle less than a round angle.