Patent GB-698647-A (GB)
Title: Combined testing device and machine tool
IPC: G01M1/38
Filed: 1951-09-06
Abstract: 698,647. Milling; machine tool details. MOTCH & MERRYWEATHER MACHINERY CO. Sept. 6, 1951 [Feb. 5, 1951], No. 21073/51. Class 83 (iii). [Also in Groups XVIII and XXIII] A machine tool, such as a milling or drilling machine or a parting-off lathe, is combined with weighing means which measure the amount of overweight of a work-piece, such as the connecting-rod or piston of an internal-combustion engine, and, according to the amount of overweight, gauging means on the machine tool are automatically set to control the tool movement so that an amount of material is removed to reduce the work to the correct weight. As described, a connecting-rod W has a projecting boss at the crank-pin end and an annular boss at the wrist pin end and is first weighed on scales M, such as those described in U.S.A. Specification 2,282,052 which indicates the overweight of both ends on indicators 24, 25, and is then placed in a work-holder 21 on a milling-machine having two separate nnits 8, 17 in which wedge stops have been adjusted by the movement of the scales through Selsyn circuits so that a side-milling cutter 10 and end-milling cutter 20 remove the correct amount of material from the bosses. The milling unit 8, Fig. 20, is mounted on a slide traversable from left to right by a hydraulic cylinder 225, Fig. 24, and its side-milling cutter 10 is mounted in a quill 27 and driven by a motor 11. The quill is fed by a hydraulic cylinder 59 connected to a bracket 39 clamped on the quill and carrying a probe 9. The milling unit 17, Fig. 21, is mounted on a slide 15 traversable from left to right by a hydraulic cylinder 140 and its end-milling cutter 20 is mounted on a spindle 105 driven by a motor 18. Operation. The amount of overweight of each end of the work W on the scales causes rotation of a pair of scale Selsyns out of correspondence with a pair of Selsyns on the milling units and the current consequently generated is amplified to operate relays causing reversible motors 132, 152 to rotate the milling unit Selsyns into correspondence. This rotation of the motors adjusts a wedge stop 71, Fig. 20, on the unit 8 and a wedge stop 121, Fig. 21, on the unit 17 and the quill 27 is then withdrawn from a previous partially-advanced position against a stop 61. The adjusted stop 71 causes a spring-loaded plunger 75 to be advanced in the bracket 39 and, through a time delay, a valve 207, Fig. 24, is operated to direct pressure to a cylinder 87 which advances a wedge 88 and pin 89 to clamp the plunger in the position determined by the stop 71. When both stops are adjusted, a warning lamp goes out, indicating that the work may be removed from the scales and placed on a pair of plugs 142, 143, Fig. 1, on the work-holder 21. A starting button is then depressed and relays operate a solenoidcontrolled valve 212 to supply hydraulic pressure from a pump 201 to a cylinder 144 which advances a clamp 146 to hold the work on the plug 142. If the work is properly loaded in the holder, a switch 149 is tripped and the build-up of pressure in hydraulic lines 208, 214 trips other switches 210, 215 so that a valve 245 is operated to direct pressure to a cylinder 59, thereby advancing the quill 27 and probe 9. Immediately before the probe engages the work, a collar 46 on it pushes a bush 48 to the left and the movement of the bush, through a rack-andpinion and a gear segment 84, positions a wedge stop 85. The movement of the bush ceases when the probe engages the work and further movement of the quill and probe compresses the spring 45 until the forward end of plunger 75 contacts the stop 85 and a limit switch 79 is operated. The switch 79 controls a valve 219 through a time-delay relay and fluid is admitted to a cylinder 91 which, by a wedge 93, causes a pivoted split sleeve to clamp the quill in the advanced position. Pressure build-up in line 220 now trips switch 222 and, through the valve 224, fluid pressure is supplied by the line 227 to cylinder 225 to traverse the slide 13 rapidly until the piston closes a side port so that the return fluid is regulated by a flow-control valve 232 with resultant slow traverse during the actual machining. At the end of the traverse, a switch 282 is tripped, causing the valves 224, 245 to be moved by springs to a position blocking both lines 226, 227 and 246, 247 for the slide traverse and quill advance, respectively, and operating the valve 207 to release the locking-pin 89 so that the plunger 75 is returned to the right by its spring. Switch 79 is thus opened and valve 219 operated to release the quill clamping means, the release of pressure in line 220 operating switch 222 and energizing valve 245 so that the quill is retracted until it operates a switch 272 and causes the valve 245 to block both lines 246, 247 and leave the quill in a partially retracted position. Operation of switch 272 also causes the slide 13 to be returned rapidly to the starting position. Simultaneously with the advance of the quill 27, the switches 149, 215 have caused a valve 235 to direct pressure to cylinder 140, thus advancing the slide 15 rapidly until the piston closes a side port so that the return fluid is regulated by a flow control valve 240 to give slow advance during machining. The depth of cut is determined by a gauging stop 23 forcing a spring- loaded plunger 119 into engagement with the previously-adjusted wedge 121 and operating a switch 115 which, through a time-delay relay, operates valve 235 first to stop the advance and then retract the slide until switch 291 is tripped to operate the valve 235 again to stop the movement of the slide. Operation of the switch 291, and of the switch 272 by the partially - retracted quill, also operate the valve 212 so that the work clamp 146 is released and the work-piece may be removed and replaced by another which has been weighed. New work may be placed on the scales as soon as one is removed but the weighing operation will not commence until the quill 27 has advanced to remove the plunger from the wedge stop 71 and the slide 15 has advanced its full predetermined distance, the quill closing switch 157 in one Selsyn circuit and a switch 170 operated by the slide 15 closing another switch in the other Selsyn circuit through a time-delay relay. The setting of the wedge 121 alone controls the depth of cut of the face-milling cutter 20, since the face of the work is always identically located, and the effect of the probe 9 in setting the forward wedge 85 is to deduct from the travel of the quill 27 the amount by which the end of the boss on the work extends beyond an arbitrary point. If the end of the work is always identicallylocated, the probe may be dispensed with. By using a rear stop 71, which is left behind after the plunger 75 has adjusted and locked, the weighing of the next work-piece can be completed during the actual milling operation. The stop 71 may be a cam or screw instead of a wedge. As an alternative to the quill 27, the slide 13 may be mounted for both longitudinal and lateral traverse and the probe may be provided with separate piston and cylinder means for reciprocating it. The work-holder may be traversed instead of the tool. Individual operation of the two slides, the quill and the work-clamp is provided for by a manual selector and push-button switches.