GB651539A - Improvements in or relating to machines for drilling button blanks - Google Patents

Abstract

651,539. Machines for drilling button blanks. EAST ANGLIAN ENGINEERING CO., Ltd. May 13, 1948, No. 13163. [Class 83 (iii)] A machine for drilling button blanks of the kind having a rotary indexible blank carrier and at least one reciprocable drilling spindle is characterized in that means are provided for indexing the drill spindle and for retaining each blank in the drilling position during a period containing two or more axial drilling movements whereby the drill enters successively holes at spaced positions in each blank. The blanks are fed automatically from a hopper 11, Fig. 1, down a shoot 12 to an indexible carrier 13, Fig. 8, provided with notches 64. The blanks 65 are retained in the carrier by spring-pressed guide-plates and clamped in the drilling position by a plate 113 operated as described below. Two opposed drill spindles 16, 17, Fig. 1, on spaced parallel axes, are provided in the example described and are driven by belts 18, 19, from a countershaft 21. Each drill spindle is mounted in its fixed housing 25, Fig. 6, within two eccentric bushes 26, 27 ; these are relatively adjustable to pre-set the spacing between holes to be drilled. The outer bush 27 is rotated intermittently to index the spindle by a gear. wheel 33 engaging a wheel 35 forming part of a Geneva wheel 36 which is driven from a shaft 38 rotated by means independent of the spindle drive. Axial movement of the spindles is obtained through a pivoted yoke-piece 41 connected to a slider 43 having a roller cam follower 45 secured to its underside; the follower is spring-urged against a cam 48 driven through bevel gears from the shaft 38. The latter is driven through a dog-clutch 123, Fig. 2, by worm gearing and in turn drives through toothed gearing in the gear-box 119 a shaft 92. This shaft may be driven at half the speed of shaft 38, or, by interchanging the gears, at a quarter the speed of shaft 38. In the latter arrangement the drills may have shouldered portions and are arranged to re-enter the holes in the opposite direction to the drilling to cut away the burrs from the " backs " of the holes. Variations in the Geneva motion and gearing enable different combinations of holes to be drilled. The blank-carrier is indexed by ratchet mechanism 72, 98, Fig. 9, arranged on the opposite side to that on which the buttons are carried. This mechanism is operated by a lever 76 pivotally connected to a bell-crank lever 77, one arm of which has a follower 82 engaging a cam 83 on the shaft 38. This cam is arranged to operate the carrier indexing means at each revolution of shaft 38 but a further cam 86 on shaft 92 lifts the follower 82 and reduces the number of carrier indexing movements to one in two, or, one in four, revolutions of shaft 38, according to the gear ratio between the two shafts. A further bellcrank lever 102 operated by similar cams on the shafts 38, 92, but arranged with a slightly longer dwell, is provided with a shoe 109 which depresses a lever 111 to release a completed blank from the clamping-plate 113, after which the button drops from the carrier and falls into a shoot 24. The Provisional Specification refers to a series of plates to be used with the hopper, each plate being suitable for a certain minimum button-blank diameter, the plate, which is rotated, allowing only blanks of the required size to pass to the machine.