Patent GB-939853-A (GB)
Title: Automatic machine for the drilling of a succession of bores in parts made of hard material
IPC: B28D5/02
Filed: 1960-08-12
Abstract: 939,853. Drilling. INDUFI S.A. DE PARTICIPATIONS. Aug. 12, 1960 [Aug. 17, 1959 ; April 14, 1960], No. 28043/60. Class 83 (3). An automatic drilling-machine comprises a workpiece magazine 33, a vertically-movable drill spindle 32, a work clamp 24 and a container 23 for finished workpieces. The drill head 21 is carried on a piston 28a resting on a roller carried by a lever controlled by a cam. The magazine 33 feeds stones to be drilled to a passage 34a which is rocked about a pivot 35 by a camcontrolled lever 38 to cause the stones to approach a feed opening through which the stones can pass singly. The stones are carried from the feed opening to the clamp 24 and from the clamp to the container 23 by oscillating transfer arms 25, 26 operated in unison by rack gearing, the arms being also raised and lowered by a cam-operated lever 45. The arm 25 carries a strap 57 which dips into an abrading and lubricating solution in a container and conveys a drop on to the work. The arms also carry air delivery and suction pipes 25a, 26a, connected to a pump operated by a cam. The work is gripped by jaws 62 on the end of a rod 60 urged upwardly by a lever 69 engaged by a weighted lever 73. The work is released by a spring 67 pulling the jaws against a conical portion 63 which spreads the jaws outwardly. The work can only be released when a cam lowers a lever 68. All the cams are on a single shaft rotated by an electric motor associated with an electromagnetic brake. In operation, the arms 25, 26 are swung and lowered and suction is applied to the pipes 25a, 26a to pick up a stone from the feed opening and a drilled stone from the work-holder. The arms then swing back and the suction is released to drop the workpieces as shown in Fig. 9. The arms continue to swing and are lowered to cause the abrasive solution to be deposited on the stone to be drilled. If no workpiece has been deposited in the holder or if the drill has broken, the rapid rising of the arm 69 causes switches 76, 77 to be closed so that a warning light is illuminated and the motor is stopped. In a modification, the oscillating transfer arms are moved vertically by separate cams and the magazine is not rocked. A hand-lever 30a, Fig. 18, permits manual raising of the drill head. Clutches, such as 190, permit the cam-shaft 78 to be rotated by a hand-lever 108. The workpiece is clamped by a rubber sleeve 110, Fig. 22, and released by pressing an apertured plate 115 downwardly to expand a collar 111 on the sleeve. A diaphragm is fitted to the sleeve 110 to connect it to a pulley 120 by which it is rotated by a motor 117, which motor also rotates the container for the abrading material. When the drill has worn to a predetermined extent, a lever, moved with the workpiece, closes a switch to stop the machine. The magazine comprises a plastic container 132, Fig. 24, and a rotary feed-wheel 133, there being a glass sheet 132c above the stones to prevent the effect of electrostatic action between the stones and the plastic. The wheel 133 is rotated intermittently by a ratchet device driven by the movement of the oscillating transfer arms. The stones are carried round until they engage one-by-one in a notch. A dog on a cam on the cam-shaft actuates a cycle-counting mechanism 144. The spindle is vibrated axially.