Patent GB-1070505-A (GB)
Title: Apparatus for resistance-selecting and short-circuiting electric detonators
IPC: F42B3/198
Filed: 1965-03-17
Abstract: 1,070,505. Feeding webs. ASAHI KASEI KOGYO KABUSHIKI KAISHA. March 17, 1965 [Aug. 6, 1964; Aug. 13, 1964; Aug. 14, 1964; Aug. 21, 1964 (2)], No. 11371/65. Heading B6B. [Also in Divisions B3, B8 and F3] Electric detonators are tested by measuring their resistance and short-circuiting them, using a turntable 1 including a number of detonator holders 2 which are indexed past working stations 4-12. Each detonator (141) (Fig. 17, not shown), including lead wires (142) having naked terminal portions (143), is fed by an operator at a feed station 3 to a clamp 2, the portions (143) being clamped in spaced relation on each side of an insulator, the portions are trimmed at station 4 and opened by a unit 15. The resistance of each detonator is measured at 5 and if the detonator is satisfactory a signal is sent to a discharging unit 6 (Fig. 5, not shown). The signal energizes an electromagnet (29) to force an arm (28) downwardly, thus urging a spring-loaded rod (22) downwardly to bring a cam (22A) out of contact with a cam (30) on the bottom of a holder 2. If a signal is not sent, due to a faulty detonator, the cam (22) rotates the cam (30) as the turntable is indexed to cause the detonator to be unclamped and rejected. At stations 7 and 8 the detonator leads are gathered together using a vertical rotating tube with a conical recess at its lower end. The leads are enclosed by a section of foil (144), Fig. 17, at station 9 (Fig. 9, not shown). Foil from a coil (40) is fed intermittently by ratchet driven wheels (41) and (42) until it reaches a cutter (49), where it is cut into a short length and then pressed downwardly in V-shape by an inserting rod (48). The foil is retained between resilient fingers (55) and is then tilted by a pinion (54) through 90 degrees to embrace the terminals. The terminals are subsequently forced into the V-shaped foil to be lightly clamped. Short-circuiting is effected at station 10 by pressing the foil tightly on the leads. The foil (144) (Fig. 12, not shown) is crimped between a cam-operated die (85) and a corresponding adjustably spring-loaded die (84). Rotation of a cam (91) moves the die (84) to the right to crimp the foil between the die (84) and the die (85) which is accommodated in a groove of a cam-operated pressure supporting rod (81). The arm (82) is moved to the left after crimping, and the die (85) and rod (81) retracted to the right by springs (89) and (88) respectively. Instead of using foil for short-circuiting the leads may be simply twisted together at station 12. The twisting machine (Fig. 13, not shown) includes a pair of arms (110) and (111) which are biased apart by springs (112) and (113). The arms are rotated by a pulley wheel (108) and lowered relative to a fixed support (100) on rotation of a cam (103) against which a follower (102) is urged by a spring (115). As the arms are lowered they are forced together by a fixed bearing (114) having a frusto-conical inner race until the leads (143) are gripped and twisted. The pulley is rotated by contact of a roller (106) on the end of shaft (105) with the side of the rotating cam (103). The terminals are finally gripped between a pair of endless belts to discharge the detonators at station 13.