Patent GB-705754-A (GB)
Title: Improvements in screw thread rolling devices
IPC: B21H3/04
Filed: 1951-06-21
Abstract: 705,754. Rolling screw-threads. KRUSE. H., and FETTE, C., [trading as FETTE, W. [Firm of]]. June 21, 1951, No. 14723/51. Class 83 (4) In a thread rolling head with rolls arranged concentrically with the workpiece and eachhaving rolling grooves perpendicular to the roll axis whereby the latter is in an inclined position to the workpiece at an angle corresponding to the pitch angle, the rolls are provided on one halt of a coupling which is axially slidable androtatable relatively to the other half of the coupling, in order that the rolls may be disengaged from the work. Rolls 3 a, b, c, Figs 1, 2, 3, freely rotatable on eccentrics 5 a<SP>1</SP>, b<SP>1</SP>, c<SP>1</SP>. on spindles 5a, b, c, are carried between plates 1, 2, which together with a housing 10 bolted to the plate 2, constitute one half of the coupling. The roll spindles carry gear wheels 6 a, b, c which mesh with a central gear wheel 7 axially slidable on a shaft 8 which 'forms the other half of the coupling. Dogs 10a on the housing 10 engage dogs 8b on a flange 8a of the shaft 8 and the housing and shaft are connected by a spiral spring 11, whose axially directed spring pressure tends to hold the dogs engaged and whose spiral spring pressure tends to rotate the shaft 8 and gear wheels 6 a, b, c; 7, in the direction indicated in Fig. 1 to open the roll pass. In operation, the shaft 8 is carried in a lathe support and the rolls adjusted to the diameter of the workpiece by mutual adjustment observed on a scale O of the plate 2 and housing 10 by means of bolts 9 a, b, c. When the end of the workpiece engages the adjustable stop 14 the dogs 10a and 8b are disengaged and the spring 11 rotates the housing 10, the gear wheels 6 a, b, c roll on the wheel 7 and the eccentrics 5 a<SP>1</SP>, b<SP>1</SP>, c' rotate to open the rolls. A hand lever 12 on the housing 10 allows the rolls to be opened by hand. The dogs are arranged stepwise to limit the relative rotation of the two halves of the coupling and ensure that the rolls will be returned to their original position. In a modification, Figs. 5 and 6, the head is rotatable. Eccentrically mounted  rolls are carried oh the rotating shaft 8<SP>1</SP> and the roll spindles are rotated by cranks 6 a<SP>1</SP>, b<SP>1</SP>, c<SP>1</SP>, engaging slots 15a of a disc 15 adjustably bolted. to the housing 10<SP>1</SP>. Axtally slidable on the shaft 8<SP>1</SP> and rotatable therewith is a control member, 17 within which is axially slidably positioned a sleeve 18 spring loaded by springs 19 and carrying dogs 18a which engage with the housing 10'. Engagement of the end of the workpiece with a stop 24 carried by a spring loaded member 22 causes this latter and the sleeve 18, by means of pins 21, to move to the right and the dogs to disengage from the housing, which then rotates under the action of the spring 11<SP>1 </SP>to open the rolls. The movement of the housing also forces the control member to the right under the action of rollers 17a moving on the inclined sides of slots 10c in the housing extension 10b. Reengagement of the rolls is then achieved by movement of the control member 17 to the left by a hand lever (not shown) engaging a peripheral groove 17b. The hand lever may also be used to disengage the rolls, slots 22a in the member 22 permitting movement of the sleeve 18 and pins 21 to the right without movement of the member 22. In further modifications, reengagement of the rolls is achieved by retarding the housing by means of a friction clutch to load the spiral spring and allow the dogs to engage. In another modification, Figs. 9 and 10 (not shown) the roll adjustment is made by segmental gears on the roll spindle which engage teeth formed internally of the housing..The roll surfaces, Fig. 11, are concave to the roll axis so that the ridges penetrate uniformly deeply for substantially the full length of the rolls, and are inclined to a degree X depending upon the characteristics, particularly hardness, of the workpiece at both ends to allow of the rolls being reversed when one set of end faces is worn.