Patent GB-279731-A (GB)
Title: Improvements in laying out system for metal cutting & like machine tools
IPC: B23Q16/00
Filed: 1927-05-18
Abstract: 279,731. Shaw, J. C., and Shaw, R. D. May 18, 1927. Drilling-machines; milling-machines. - In a method of and apparatus for spacing work on milling-machines, die-sinking machines, drillpresses &c., a feed mechanism is operated by an electromagnetically controlled clutch in circuit with a contact which may be displaced by an adjustable dog to stop the feed at any required point. The feed may be operated from an electric motor or by hand. As applied to a milling or die-sinking machine, the work 20 is secured by dogs 21 on a table 11 movable by a screw 13 on guides 12 carried by a saddle 2 slidable along guides 3 on the machine frame by a screw 4. When a power feed is used an electric motor 10 rotates a bevel pinion 9 which drives bevels 8 in opposite directions, each of the bevels 8 carrying an electromagnet 5 adapted to co-operate with an armature 6 slidably keyed to the end of the screw 4. An identical drive is provided for the screw 13, controlled by electromagnetic clutches 14. The clutches 5, 14 are in a high-tension circuit of 110 volts supplied by the mains, the circuit being completed from the negative main L- to the position L+ through a relay switch 52 and double-pole switch 63. The relay 52, which is normally opened by a spring 53, is controlled by an electromagnet 48 in circuit with a low-tension generator 50, a contact 43 fixed on the machine frame and a contact 42 on a lever 24 pivoted to the machine frame. The contacts 42, 43 are normally closed by a spring 45 and the lever 24 carries a hardened button 25 which is engaged by a stop on the saddle to stop the feed at a predetermined point. The stop may comprise theend 26 of a micrometer 27 carried by a block 28 adjustable along a bar 29 fixed to the saddle 2, or the end of a vernier slidable along a scale which replaces the bar 29, or by the end of a variable gauge made up of gauge-blocks. The block 28, Fig. 4, is secured to the bar 29 in its adjusted position by a screw 32 and is provided with a recess 36 to receive a gauge rod 40 which contacts with a hardened stud 37 at the end of the recess. The interchangeable gauge rod 40 is used for setting the block 28 relatively to a fixed block 33 carrying a projecting hardened stud 39. In operation, to locate a point A on the work at a given distance from the machined edges 87, 88, the procedure is as follows :-The tool is preferably removed from its spindle, represented by the circle B, Fig. 1, and replaced by an arbor having an accurately ground button at the end. The clock 28 is moved along the bar 29 until the studs 37, 39 are in contact and is then locked in position. The switch 63 is next closed to actuate the appropriate clutch 5 and traverse the saddle until the button 25 on the lever 24 encounters the end 26 of the micrometer 27 and thereby breaks the contacts 42, 43 and allows the spring 53 to break the circuit to the clutch and stop the traverse of the saddle. Tc establish a zero reading the distance from the spindle B to the edge 87 is measured and the block 28 is then displaced along the bar 29 by means of gauge rods 40 and adjustment of the micrometer by a distance equal to the difference between the points A and B from the edge 87, the saddle having meanwhile been withdrawn, to allow the setting to be made, by closing the switch 63 to energize the reverse clatch 5. The switch 63 is then closed to move the buttons 25, 26 into contact, whereupon the saddle is stopped with the spindle B in the same vertical line as the point A. A similar adjustment having been made in a vertical direction, the point A is located exactly. Should the spacing mechanism not be required, a bridge connection 65 is substituted for the socket connection 56 to short-circuit the relay 52. In a machine wherein the screws 4, 13 are operated by hand, a single electromagnetic clutch is interposed between each hand-wheel and its screw and is controlled by a relay such as the relay 52, so as to declutch the handle from its screw when the buttons 25, 26 engage. Driving machines; gauging-devices. - The method and apparatus are stated to be applicable to other metal-cutting and like machine tools such as lathes and planing-machines.