Patent GB-257178-A (GB)
Title: Machine for producing wood screws from pressed blanks
IPC: B23G7/00
Filed: 1926-03-01
Abstract: 257,178. Weber, G. March 1, 1926. Turning wood-screws; steady rests.-Wood-screws are made from pressed blanks by successive operations of threading, nicking, and turning the head, in a machine comprising an intermittently rotated work carrier which is provided with a number of circumferential grooves adapted to receive the blanks at a feeding station and to convey them. at each part-rotation. to the successive working stations. The workcarrier 4 is mounted on a shaft 3, and comprises end walls connected by four radial walls, and the blankholding grooves 5 are provided in removable blocks 6 fitted at the corners of the work holder. The blanks are retained in their grooves by spring-pressed levers 7 pivoted on shafts 8 which also carry levers 10 which may be actuated when required to release the clamping-levers. The shaft 3 may be moved axially by a lever 11 actuated bv a cam 15 on the cam-shaft 16. The working positions are determined by the engagement of a locking pi 19, carried by a disc 17 secured to the shaft 3 with recesses 20 located in a flange on the fixed bearing 2. When the shaft 3 is moved rearwardly by the lever 11 the locking pin is disengaged whereupon the indexing movement is effected by a pin 22 which is carried by a link 23 actuated by a lever 25 and cam 27 and is adapted to engage holes 21 in the disc 17. Finished work-pieces are ejected and fresh blanks fed to the work-holder at the station A. The feed mechanism comprises an inclined shoot 28 which, in order to permit the indexing movement, may be moved by cam End lever mechanism about a pivot 30 to the position shown in dotted lines in Fig. 1. When the shoot is in operative position. a finger on a vertical rod is actuated by lever mechanism to press the shank of the blank into one of the grooves 5, the clamping member 7 being pushed aside against the pressure of the spring 9. The ejector mechanism which acts immediately before the blank feed comprises a rod 35 carrying an Ejecting pin 36 and actuated through lever mechanism from a cam, the finished screw dropping on to a shoot 40 and passing to a receptacle. The blanks are threaded at the station B. The forward axial movement of the work holder ir to its locking position brings the head of a blank between the jaws 41 of a chuck which is then closed. In order to allow the blank to be rotated, the clamping lever 7 is withdrawn by mechanism engaging a finger 49 on the arm 10. A thread cutter 42 is mounted in a holder 43 secured to a rotatable and axially movable shaft 44, rotation of this shaft to engage the cutter with the work being effected by a cam 46. Further lever mechanism is employed to give the longitudinal movement to the cutter in correct relation with the rotational speed of the chuck 41. After completion of the threading, the chuck is opened, the blank withdrawn by the rearward unlocking movement of the work holder, and, at the next indexing movement, conveyed to the station C where it is nicked by a circular saw 50 driven from a shaft 57 through bevel gearing 56 and spur gears 55. The bearings 52 of the sawspindle are carried by arms 53 which are oscillated about the shaft 54 to bring the saw up to the blank by a connecting rod 58 actuated by a cam on the shaft 16. In order to hold the blank during the nicking operation, the arm 61 mounted on a sliding member 60 is moved by a cam lever 62 to press against the clamping lever 7. Areversible ,plate 63 carried by the arm has bevelled notches 64 one of which passes under the head of the screw to provide further support during the nicking. The blank is next moved to the station D where the head is turned by a rotary tool head comprising a sleeve 66 rotated by a spur wheel 67 and provided with levers 71, 72, pivoted at 68 and carrying at their outer ends a profiled turning-tool 76 and a steady rest 77 respectively. The turning-tool is adapted to finish the plane and conical faces of the head simultaneously. The steady rest has recesses 78 one of which is adapted to support the screw blank immediately below the head. The levers 71, 72, are closed after the insertion of the blank by a wedge member 75 which is so shaped that first the steady rest is brought up to engage the blank and then the turning tool is gradually fed forward, the blank being held in its groove against rotation by a finger 82 on an arm 81 secured to the sliding member 60. The finished blank then moves to the station A where it is ejected. The tool 42 may be replaced by a milling-cutter.