Patent GB-477474-A (GB)
Title: Improvements in or relating to machines for effecting milling, profiling or the like operation
IPC: B23Q35/18
Filed: 1936-09-02
Abstract: 477,474. Milling-machines. CINCINNATI MILLING MACHINE CO. Sept. 2, 1936, No. 24058. Convention date, Sept. 11, 1935. Addition to 461,596. [Class 83 (iii)] [Also in Group XXIX] The milling or like machine as described in the parent Specification is modified by the provision of servomotor mechanism adapted to provide rapid traverse of the moving parts as well as feed movements. The bed 10 has longitudinal ways 11 for a table 12 and transverse ways for a ram 14. The front of the ram has vertical ways for the tool head 16. A cylinder 18 secured to the bed has a fluidpressure piston 19 which operates the table 12, the control being effected by a servo-valve mounted in a housing through which passes a non-rotary lead screw 23, Fig. 18a, working in a nut 24 abutting the spring-pressed valve plunger 25. The nut is splined to a sleeve 27 carrying a spiral gear 30 by which the nut is rotated to operate the valve plunger and admit fiuid to the cylinder, thus moving the lead screw to reposition the valve plunger to stop flow to the cylinder. The valve plunger operates in a ported sleeve 31<1> which is connected by a line 45 to a, constant delivery pump 46 driven by a motor 47. The gear 31, Fig. 13, which rotates the nut is mounted on a shaft 53 journalled in the table apron 54 and operable at high and low speeds either by hand or by power. The end 57 of this shaft carries a splined clutch member 58 and a loose sprocket wheel 59 which may be operated from a hand wheel 64 through chain gearing 60. The apron 54 also carries a power shaft 66 driven by belt gearing from a motor 71 and carrying a bevel gear which has a friction surface driving a friction gear on a shaft 79. The bevel gear also drives a gear 71<1> mounted on a shaft 77 and connected by clutch teeth to a gear pair 104, 106. The shaft 79, driven at variable speed by the friction gearing under the control of a shifter fork 80, carries a clutch member 91 connectable to a pinion 92 engaging the gear 104. The lever operating the clutch 91 also operates the clutch 78 whereby the gear 104 is driven at high speed for quick traverse, the clutches being selectively engaged by oscillation of a shaft 99, Fig. 7, by means of a control rod 102. The gears 104, 106 drive in opposite directions gears 108, 109 which are selectively engaged by a reversing clutch member 111 on a shaft 53. The positions of the clutches 111, 78 and 91 are controlled by a single reciprocating member 103, Fig. 7, operated by a lever 122 on a shaft 123 which may be actuated from a handle 124 either manually or by dogs 126, 127 on the table. The member 103 has rack teeth operating a cam 113 which controls the reversing clutch 111. When the lever 122 is in neutral position the slow feed clutch 91 is engaged and a hydraulic cylinder 130 is actuated to rock a lever 132 so as to engage the manual clutch 58 and lock the control member at 134. For power operation the lever 124 is moved to position 135 or 136, Fig. 8, whereupon lever 133 is rocked to disengage the hand feed clutch 58 and to operate reverse clutch 111 in one direction or other. Further movement of lever 124 to 138 or 139 causes the bevelled parts 137 of the member 103 to raise the rod 102 and rotate shaft 99, thus disengaging the feed clutch and engaging the rapid traverse clutch 78. The interlock cylinder 130, Fig. 18, is supplied from the line 45 through a resistance 140 and line 141, which is also connected to the servo-valve so that if excessive movement of the servo plunger occurs the line 141 is opened to exhaust and the clutch 58 disengaged by a spring 146. When the rapid traverse clutch is engaged a valve 148 is automatically opened to admit fluid from a rapid traverse pump 151 into the supply line 45 to augment the supply to cylinder 18. The ram 14 is operated by a cylinder 159, Fig. 5, connected to a second servo-valve 166 similar to the valve described above but supplied from an independent pump 168. The servo-plunger may be operated either from a hand wheel or by power means comprising both feed and rapid traverse drives similar to those described above. A trip control plunger is operated by dogs on the ram to actuate the member 103. A valve 196 controls delivery from a rapid traverse pump 151 to augment the fluid supply to the servo-valve when the control member is in rapid traverse position. The ram houses the motor 200 which drives the tool spindle 17. For this purpose the motor is connected through belts 202 to a variable speed gear-box 205 whereby a shaft 215 may be driven at eight speeds. This shaft drives a vertical shaft 217 which passes into a housing 218 forming part of the tool head and which drives a sleeve pinion 219 connected to a gear 221 splined on the tool spindle. The sleeve pinion is formed with clutch teeth 222 and may be moved vertically to move the gear teeth out of mesh with the gear 220 and to engage the clutch teeth with teeth 227 on a member connected to the spindle by belts 230 to impart a high speed spindle drive. The spindle head is counterbalanced by a weight suspended from a chain 235. The tool-head 16 is moved vertically by a cylinder 238, Fig. 16, moving over a stationary piston 239 and connected to plates 245, 246, Fig. 17, which for plain milling operations connect the lines 241, 242 with lines 247, 248 leading to a servo-valve 253 supplied by a pump 256. The valve plunger carries a lead screw 260 running in a fixed nut. The movement of the cylinder 238 initiated by rotation of the lead screw causes movement of the valve housing 253 to stop the cylinder movement. A gear 262 is keyed to a shaft 266 connected by a sliding joint to the lead screw, the shaft 266 being rotatable for manual operation by either of the hand wheels 270, 273. The tool head movement is indicated by a scale. For power rotation of the lead screw a detachable power bracket, Fig. 15, may be secured to the tool head to drive the gear 262 which meshes with gear 280. This gear is connected through reversing bevel gearing to a shaft 286 driven by a motor 288 through variable friction gearing 287 similar to that described for the table drive. The reversing clutch 282 is operated by a shifter rod 291 controlled by a handle 295 or automatically by dogs secured to a rotatable dog carrying member 306. For adapting the machine for tracer control an additional bracket 310 is bolted to the power bracket and includes an interlock valve 312 and tracer control valve 314 which are connected to the supply by substituting a plate 279, Fig. 16, for the plate 246. The tracer control is similar to that described in Specification 477,456. The bracket 310 carries a slide 316 having guides for a horizontal slide 318 to which the tracer head 317 is adjustably clamped. The ram and table may then be manually or power driven to guide the tracer over the pattern, the vertical movements being automatically effected by the tracer. In some cases a narrow cam plate 321 may be attached to the side of the bed and the tracer aligned with said cam while the cutter reproduces the profile during the ram movement. The table is then indexed longitudinally and the operation repeated so that any length of surface may be produced from a narrow cam.' In a similar way the tracer may be set over a longitudinal cam 323 and a cut made by reciprocation of the table, the ram being then indexed transversely while keeping the slide 318 stationary and the table reciprocation repeated. A radiator 330 is mounted in the bed of the machine and an electric fan 331 maintains the circulation of air therethrough.