Patent GB-931276-A (GB)
Title: Automatic multiple spindle machine tool
IPC: B23B39/16
Filed: 1961-03-28
Abstract: 931,276. Programmed electric control systems. KEARNEY & TRECKER CORPORATION. March 28, 1961 [Oct. 31, 1960], No. 11272/61. Class 38 (6). [Also in Group XXII] A multi-spindle drilling machine comprises a bed 20, Fig. 1, a drill head 25 movable on ways 26, 27 by an hydraulic motor 30 which drives a screw-and-nut mechanism (not shown) a machining cycle control box 65 mounted on the drill head, a set-up device 95 for automatically setting the tool spindles and the control box, and a tape-reader 115, which transmits the information supplied by a tape 117 to an electrical control circuit in cabinet 118 to regulate the machine operation. The drill head 25 has ten spindles 35 to 44 journalled in laterallyadjustable guides 45 to 54 and driven by an hydraulic motor 60 which is connected to a transmission 61, Fig. 4. Each spindle, e.g. 36, Figs. 3, 4 and 5, is journalled in a guide 46 by sleeve bearings 196, 197, carried by guide 46, and is held against a thrust bearing 202 by lock nuts 203. Guide 46 extends through a slot 215 in head 25, and is clamped against face 216 of the slot by hydraulically-actuated clamps 226, 227 which pass through an elon gated slot 225 in guide 46. Clamp* 227 which is laterally fixed in head 25, has a clamping head 228 which is urged against a face 219 of guide 46 to clamp the latter, by Belleville washers 237, and is released by an hydraulic cylinder 241 whose pistonrod 242 engages a bolt 240, in the clamp 227. Laterally movable clamp 226 is carried by a slotted bridge clamp 250 and a bearing 252 on the clamp engages a further slot 253 in a web 232 of head 25. A further bearing 260 on the clamp engages a slot 261 in a second bridge clamp 262 which is axially movable on pins 275, 276, and has screwed thereto a slotted plate 265. Bearing 260 is retained in slot 261 by a sleeve 268, washer 270, and nut 269, secured to the end of clamp 227. Slots 251, 253, 261, 267 are aligned so that with clamps 226, 227 released, guide 46 can be adjusted radially relative to fixed clamp 227, and can be pivoted about clamp 227 with clamp 226 moving transversely in the aforesaid slots. Bridge clamp 250, is moved in a direction to engage a collar 249 on clamp 226, and thus clamp guide 46 by Belleville washers 285, 286, and is released by hydraulic cylinders 193, 194. Each of the guides 45-54 has a fixed clamp and a movable clamp, with a common set of bridge clamps for guides 45-47, and 48, 49, and 50- 52, and 53-54. each actuated by a pair of hydraulic cylinders, and a separate cylinder for each fixed clamp. Set-up device 95 comprises a base 96 slidably supported on ways 21, 22, on bed 20, a column 97 integral with the base and a spindle grip 98 axially and vertically movable relative to column 97, which engages spindles 35-44, and levers 66, 78, 82, 92 in control box 65 to move them to their required position. Grip 98 is carried by a slide 162, Fig. 6, vertically movable in column 97 by a screw 106 rotated by an hydraulic motor 105 to engage a nut 107, and is slidably supported for axial movement by bearings 171, 172, in a cylinder 173. Such movement is produced by hydraulic pressure passing through ports 184, 185, and engaging a piston 175 on grip 98. A drive unit 90, Fig. 1, is connected to set-up device 95 by a screw 109 and the two assemblies are movable together along the ways 21, 22 between an operating position in front of head 25, and a parking position at the right-hand end of the ways, by a piston and cylinder assembly 123. When the assembly is moved to its operating position a bolt 127, Fig. 7, locates unit 90 on the bed, a pair of hydraulic pistons 132 are actuated to clamp unit 90, an hydraulic motor 108 is actuated to drive screw 109 which co-operates with a split backlash eliminating nut 128, 129, secured to base 96 to move the latter relative to unit 90. Cycle control box 65 comprises levers 66, 78, 82, 92, which are vertically adjustable in slots in box 65 by grip 98, the levers being connected to slides of potentiometers which when adjusted, regulate the rate of feeding head 25, speed of spindles 35, 44, the points at which fast traverse and feed rate of head 25 occur, and the point at which the feed drive of head 25 is reversed to retract the latter respectively. A lever 146 is also engageable by grips 98 to be moved horizontally to the left to close a switch to establish the feed cycle for performing a tapping operation, or to the right to open the switch for other operations. A bracket 550, Fig. 9, mounted on bed extension 23, carries a screw 551 rotated by an hydraulic motor 86, which engages a nut 553 to move the latter along the screw. A slider 554 of a potentiometer is secured to the nut and the latter carries a dog 87 which engages a limit switch 560 carried by the head 25 to change the feed rate of the latter. A second hydraulic motor 561 is mounted on bracket 550 and a screw 562 rotated by the motor engages a nut 564 secured to a slider 565. A dog 88 on the nut engages a limit switch 570 on head 25 to terminate and reverse the direction of the feed of the latter. A third limit switch 575 carried by head 25 is engaged by a dog 576 to terminate the movement of head 25 in the retracted direction. In operation, a manually operated switch located in control panel 117, Fig. 1, is actuated to supply hydraulic pressure to the piston and cylinder mechanism 123 which moves assemblies 90, 95 up to their operating position. A further manual switch is actuated to supply hydraulic pressure to pistons 132 and assembly 90 is clamped to the bed 20. Grip 98 is retracted and the tape 117 is moved through tape reader 115 to operate a control circuit for actuating motors 105, 108. The first block of information on the tape therefore moves grip 98 in its retracted condition into alignment with one of the spindles 35-44, e.g. spindle 35. The tape control circuit includes discriminator circuits which compare the required vertical and horizontal positions of grip 98 as supplied by the tape, and the actual positions indicated by feed-back devices 130, 170, Fig. 7, carried by assembly 90 and column 97 respectively and the motors 105, 108 rotate until the positions coincide. A new block of information on the tape provides for supply of hydraulic fluid to cylinder 173 which moves grip 98 into engagement with spindle 35 and when fully advanced a dog 186 actuates a limit switch 187 to energize a solenoid which actuates a valve which supplies hydraulic pressure to cylinder 321, Fig. 5, thus compressing Bellville washer 320 to release clamp 312, and to a further solenoid to supply pressure to cylinders 297, 298, thus releasing bridge clamp 250. Motors 105, 108 move grip 98 along with spindle 35 into the required position according to information supplied by the tape, and grip 98 is retracted, whereupon clamp 312 is actuated to clamp guide 45, and a limit switch 189 is actuated by a dog 188 to actuate the tape reader for supplying a further block of information. This procedure continues for each spindle except that when a group of spindles say 35- 37, is located the bridge clamp is actuated to grip the guides 45-47. Grip 98 also locates the levers 66, 78, 82, 92, 146 of cycle control box 65 in the same manner from information received from tape 117. The set-up device 95 and drive unit 90 may be used for a battery of machine tools.