Patent GB-655353-A (GB)
Title: Improvements in or relating to drilling machines for drilling and swarf clearing
IPC: B23Q15/00
Filed: 1947-11-14
Abstract: 655,353. Control of motors. REGIE NATIONALE DES USINES RENAULT. Nov. 14, 1947, No. 30333. Convention date, Jan. 24. [Class 38(iii)] [Also in Group XXII] An electric-motor control system for a step-by-step drilling machine (see Group XXII), comprises a distributer (not shown) of the kind described in Specification 634.539, having contacts '2D to 6D operated by a cam P which is provided on the moveable tool-head, and a distributer switch 29 operated by another cam for advancing the head rapidly under the influence of a high-speed traversing motor and a feeding and drilling motor, stopping the traversing motor just before the actual drilling operation commences, re-starting the traversing motor in the reverse direction to withdraw the head, and reversing the traversing motor to repeat the cycle. In the inoperative position, the switches o are closed, button 2 has been pressed to energize relay 3 and close the contacts 3a, 3b, and the other contacts are as shown. The drilling motor, controlled by a relay 12, and the traversing motor, caused to advance the head by control of a relay 6, are energized by depressing a button 10, the relay 12 then closing contacts 12a, 12b and the relay 6 opening contacts 6a, 6b. As the head advances, the first surface on the cam P closes contact 6D, the second surface closes contact 2D and the third surface closes contact 4D and opens contact 3D, subsequent surfaces temporarily closing contact 3D and opening contact 4D. The traversing motor is stopped when the switch 29 is opened and the drilling operation commences with only the drilling motor operative, de-energization of the relay 6 effecting closing of the contact 6b and the contact 6a which has a time-delay. If the switch 29 is opened immediately before the third surface on the cam P has influenced the distributer, this surface would not be effective in producing a withdrawal of the head because of the time-delay of contact 6a. Upon the next following notch in the cam P closing the contact 3D, a relay 7 is energized through contacts 6a and 4D and effects operation of the traversing motor in the reverse direction and opening of a contact 7b in order to withdraw the drill. The rapid withdrawal is terminated by the cam P opening the contact 4D which de-energizes the relay 7 resulting in the closing of contact 7b and the re-energization of relay 6 to again effect rapid advance. This rapid advance continues until terminated by the switch 29 with the drill almost in the most forward position previously reached. The time delay of the switch 6a then allows the next surface on the cam P to pass the distributer without reintroducing the traversing motor. A succession of steps are introduced into the drilling operation until the maximum depth has been reached, when the cam P opens the contact 5D which de-energizes the relay 12 resulting in a contact 12c being closed and the relay 7 being energized through the contact 2D. The cycle is ended when the contact 2D is opened by the cam P. The machine may be stopped by temporarily depressing a button 1 which de-energizes the relay 3. By temporarily depressing the button 2, a circuit may be made through contacts 12c, 2D to withdraw the head. A button 17 may be temporarily depressed to de-energize the relay 6 and energize the relay 7. A button 11 may be held in the depressed position to energize a relay 9 which opens contact 9a and closes contact 9b to effect withdrawal of the head until contact 6D is opened. The button 11 may be depressed temporarily so that the return of the head is stopped by the contact 2D.