Patent GB-983294-A (GB)
Title: Controlling device for automatic machines, especially wood-working machines
IPC: B24B21/00
Filed: 1961-04-10
Abstract: 983,294. Abrasive band machines. K. HEESEMANN. April 10, 1961 [April 8, 1960], No. 12820/61. Heading B3D. In a controlling device or automatic machines, particularly woodworking machines, for the control of movements from a time switch system by which the movements of devices operating in the zone of the workpiece are automatically controlled in accordance with the different speeds at which the workpiece passes through the machine, in the feed zone of the workpiece at least one mechanical control element in the form of an abutment roller actuated by the workpiece when the latter arrives at a predetermined position closes the switch of the time switch system to effect, through mechanism driven from the drive for the workpiece feed, the control operation. An endless grinding band 5 passes round pulleys 3, 4, the pulley 3 being driven by a motor 3a. A workpiece 12 is fed under the lower run of the band 5 by an endless conveyer band 10 passing round cylinders 8, 9 carried by members vertically adjustable on uprights which carry the pulleys 3, 4. The cylinder 8 is driven by a motor 8a through an infinitely variable gear 8b. A table 11 is located below the upper run of the conveyer band 10. A pressure beam 15 is movable by a piston and cylinder device 16 through levers 15a so that it can be lowered to press the lower run of the grinding band 5 against the workpiece. An arm 13a carries a housing 19b supporting a roller 19 spring-urged towards the conveyer band 10 and in the path of the workpiece. When the leading edge of the workpiece forces the roller 19 up, contacts 21 in the housing 19b are closed, energizing an electromagnet 22 which moves a roller 23 to press a rod 24 into contact with a friction wheel 25 on a shaft 25a connected to the cylinder 8. The rod 24 is raised by the friction wheel 25 and in its upper position a trip finger 24a thereon actuates a switch- 26 thus energizing an electromagnet 26a which actuates a valve 16a controlling the admission of air to the device 16 so that the beam 15 is lowered into its operative position. The stroke of the rod 24 is so adjusted by a screw 27 that the rod travels from its lower position to its upper position while the leading edge of the workpiece travels from the roller 19 to a position 14 under the band 5. Simultaneously, with energization of electromagnet 26a, the electromagnet 22 is de-energized and the rod 24 falls. When the roller 19 runs off the trailing edge of the workpiece, an electromagnet 29 is energized and moves a roller 30 to press a rod 31 into contact with a friction wheel 32 on the shaft 25a. The rod 31 is raised by the friction wheel 32 until a trip finger thereon actuates a switch, whereby the electromagnet 26a is de-energized and the pressure beam 15 moved upwardly when the trailing edge of the workpiece has reached a position 18 as determined by the setting of a set-screw associated with the rod 31. Instead of the rods and friction wheels, toothed racks with pinions or cam switch wheels may be used. When the workpiece reciprocates, a second roller is provided.