Patent GB-683595-A (GB)
Title: An improved method of and apparatus for manufacturing nuts for bolts or like
IPC: B21K1/64
Filed: 1951-06-18
Abstract: 683,595. Making nuts. FRAY, V. H. June 18, 1961 [Nov. 21, 1960], No. 14376/51. Classes 83 (ii), 83 (iii) and 83 (iv). [Also in Group XXIV] Punching.-A method of making nuts comprises feeding a strip into a press which punches a series of holes, feeding the strip into a tapping device either by means of the holes or by means of notches formed in the edges of the strip and then feeding the strip into a machine which punches out nuts having the tapped holes at the centres. The punching machine comprises a table 2, Figs. 1 and 10, with two guide grooves, along the first of which the strip 7 is fed by rolls 6, 6a, and a cross-head 3 carrying punches 8 and 9 and reciprocated from a crank-shaft 4 which also drives the feed rolls through a pawl- and-ratchet. From its first passage through the press during which the punch 8 forms a series of equidistant holes, the strip forms a loop 7a leading to a device for tapping the holes and then forms another loop 7b and passes again through the press where the nuts are removed by punch 9. During this second traverse the strip is fed by a pivoted lever 13, Fig. 7, carried by the cross-head 3. On the descent of the cross-head, a pin 22 at the lower end of the lever enters a tapped hole and as the upper end moves clear of a bar 15, a spring 18 rotates the bar as far as allowed by a stop 23 to feed the strip forward in its guide groove beneath the punch 9. Tapping.-The tapping device comprises a frame 24 along the base of which the strip is fed by an intermittently-rotated sprocket 27, Fig. 4, with teeth which engage in the holes 10. Secured to the frame are two guide-rods 39, 39a carrying a cross-head 40 which may be moved down against springs 42 by a cam 61. Mounted in the cross-head are two spindles 44 carrying taps 58 and secured to each spindle is a double-faced cone 45 positioned between upper and lower conical friction clutch members 46, 46a, Fig. 5, rotated in opposite directions by skew gears such as 48, 49 from shafts 50, 52 driven by a pulley 55 and coupled by gears 54, 84a. The cam 61 controlling the movement of the cross-head is driven by a chain and sprocket from the press crank-shaft 4, the chain also driving the feed sprocket 27 through Geneva mechanism. The cam is connected to its driving-shaft 62 through a plate 64 carrying two pins 64a, Fig. 11, pressed by springs 65 into two depressions formed in the cam at different distances from the centre. If, during the descent of the cross-head a pin 59 does not enter a hole 10, the pressure causes the plate 64 to move independently of the cam 61 for a complete revolution, while the springs 42 force the cam back slightly while another feed movement of the strip occurs. If the pin 59 does register with a hole, then each tap will register with a hole, the pressure on the spindles causes them to engage the upper clutch parts 46 and rotate the taps to form the screw threads. On an upward movement of the cross-head, the cones will be engaged by the lower clutch part and the taps rotated in the reverse direction and extracted.