Patent GB-403534-A (GB)
Title: Improvements in or relating to machines for drilling holes in doors and inserting retaining pins in such holes and within the joining dowels
IPC: B27F4/00
Filed: 1933-02-13
Abstract: 403,534. Control of several motors. WELCH, A. R., 106, Karr Avenue, Hoquiam, Washington, U.S.A. Feb. 13, 1933, No. 4400. Convention date, Feb. 23, 1932. [Class 38 (iii).] Travelling to predetermined limits. In making wooden doors according to the method described in Specification 384,145, [Group X], a machine is used in which the various movements are effected by separate electric motors which are controlled by relay switches to ensure the correct sequence of operations. The machine comprises side frames 9, 90, Fig. 1, which are moved to and from each other to clamp the door D by means of right and left handed screws 93 driven by a hand-controlled clutch 97 and oppositely rotating clutches 95, 96 rotated by an electric motor 99. A drilling unit is mounted at each corner of the door D, as shown in Fig. 1, and in operation, the clutch 97 is actuated by a hand lever 97<1> to rotate the screws 93 in the closing direction and a switch is operated to start the motor 99. The circuit to this motor is maintained by a solenoid and is completed through a switch 8 on one drill head to ensure the latter being fully retracted before the clamp can close. Switches 7, one on each drill head, in circuit with the motors 6 for feeding the drills, are held open by fingers 71 on the slides 4 when the latter are retracted, in order to prevent movement of the drill-heads until a push button, in parallel with the switches 7, has been actuated manually to energize a relay and close the circuits to all the motors 6. The drills then commence their feeding movements, thereby closing the switches 7 so that the push button may be released by the operator, the motor circuits being maintained closed by solenoids. As each drill head is retracted after the drilling operation, a stationary spring catch 50, Fig. 5, engages a pin 54 on a rotatable cam 5, thereby turning the cam through 90‹ and causing a rise 51 thereon to engage a roller 53 on the holder 10 to oscillate the latter about its pivot 40 into the position shown in Fig. 5. In this position, the fingers 71 are out of line with the switches 7 so that the circuits to the motors 6 are not broken, and at the next forward reciprocation of the carriages 4 the hoppers 2 are brought against the door D. The springs 21 are then compressed and ejectors 22, in line with the holes drilled in the work, press two pins out of the bottom of the hopper into the drilled holes. As the carriages 4 are retracted, the cams 5 are again rotated through 90‹ and the drills are returned to the horizontal position shown in Fig. 3, whereupon the fingers 71 engage the switches 7 to open them and stop the motors 6, and the switch 8 is closed to allow actuation of the motor 99 when the appropriate switch is operated manually. With the clutch 97 in the reverse position, the screws 93 are now rotated to open the clamps and release the door. The motors 15 which drive the drills are rotated continuously and are started by a push button which energizes a solenoid to maintain the motor circuit switch closed, these circuits embodying thermo control elements. Emergency press buttons are provided for stopping any of the motors at any time. The Specification includes a wiring diagram of the circuits used.