Patent GB-831644-A (GB)
Title: Improved thread rolling head
Inventor: BOTHE KURT
IPC: B21H3/04
Filed: 1956-02-10
Abstract: 831,644. Rolling screw threads. WERKZEUGFABRIK TREPTOW VEB. Feb. 10, 1956, No. 4173/56. Class 83 (4). In a thread rolling head having freely rotatable rolls 7, Fig. 1, which are radially displaceable on eccentric shafts 8 to release the work, the shafts 8 are adjustable for pitch angle and are carried by articulated bearings 9 in a casing 6 and a rotatably adjustable bearing plate 1, while means is provided for preventing relative movements between the shafts 8 and rotatable controlling elements such as gears 14. The bearing plate 1 is attached to distance pieces 2 of the casing 6 by means of screws 3 engaged through slots 3a, Fig. 4, in the plate 1 to permit the required adjustment for right- or left-hand thread. The shafts 8 have pins 8a at each end which are mounted in pivotal bearings 9 articulated on pins 9a. At one end the pins 9a pivot in the plate 1 and at the other end the pins 9a pivot in bearings 12. Distance discs 10, 10a limit the axial movement of the rolls 8. The eccentric shafts 8 are rotated to release the work by the gears 14 which are coupled to the shafts through square-ended engagement members 16 located in recesses 19a of the gears and held axially by pins 17. The gears 14 are automatically rotated by spiral springs 24 when the required length of thread has been rolled, the spring loading then being reset before the next rolling operation. In a modification the pins 8a, Fig. 5, are connected to the gears 14 through a spherical or universal joint 9d. The rolling head carrying the spring loading means comprises a carrier 18 attached to a rotating member such as a lathe head by means of a flange 43 through an intermediate cylinder 30, pins 42 and roller bearing 31, The casing 6 is secured on the member 18 by a handle 21 and a work-receiving tube 27 is rotatably mounted at the centre of the carrier 18. The springs 24 are mounted between tensioning rings 25, 26 keyed to the carrier 18 and tube 27 respectively, a gear 15 keyed on the tube 27 engaging the gears 14 to rotate the shafts 8 and release the work when relative rotation between the tube 27 and member 18 is permitted. This rotation is normally prevented by keys 28 attached to a flange 27e of the tube 27 and engaging recesses 29 'in the carrier 18. Initial adjustment of the eccentricity of the shafts 8 may be made by relative rotation of the casing 6 on the carrier 18 and locking in position by a handle 21 passing through a circumferential slot 22 and screwed into the carrier 18. The tube 27 is rigidly attached to a retaining ring 32 having a key 39 projecting through a circumferential slot 37 in the cylinder 30 and engaging a traversing ring 41 which is moved longitudinally by means (not shown) as the work traverses, and finally moves the tube 27 to release keys 28 by engagement with the keys 39. Relative rotational movement between the tube 27 and cylinder 30 is limited by the engagement of the key 39 with the side wall of slot 37. The springs 24 are reset on return of the traverse by engagement of the ring 41 with a brake 34 which causes the carrier 18 to rotate relatively to the cylinder 30 and tube 27 until the key 39 engages the opposite side wall of the slot 37 at which position the keys 28 re-engage. The springs 24 are alternatives for right or left hand thread and are selectively engaged for operation by grub-screws 26b, 26c.