Patent GB-461596-A (GB)
Title: Improvements in or relating to machines for effecting milling, profiling, or the like operation
IPC: B23C1/027
Filed: 1936-04-29
Abstract: 461,596. Fluid - pressure servomotor - control systems. CINCINNATI MILLING MACHINE CO. April 29, 1936, No. 12191. Convention date, May 31, 1935. [Class 135] [Also in Group XXII] A machine for milling, profiling, or like operations has the slides actuated by servomotor mechanism including a control device one part of which is mounted on a slide and which is operated selectively either manually or by power to cause operation of the servo mechanism to move the slide. In the application to a milling machine, the work table 10, and saddle 11 move horizontally in perpendicular directions, and the saddle carries a tool-head 12 which is movable vertically. The table is traversed by a hydraulic cylinder 13 while the saddle 11 and tool-head 12 are similarly traversed by hydraulic cylinders 19, 24, respectively. The servomotors controlling the admission of fluid to these cylinders are all of similar construction, the cylinder 24 being supplied by pipes 29, 30, leading from longitudinal passages 35, 36, in a valve member 33 carried by the slide 12 and supplied by a pipe 40 leading through a central passage 39 to a diametral bore 41. The passages 35, 36, lead to annular grooves 37, 38. An outer sleeve 44 of the valve is provided with pairs of arcuate exhaust grooves 46, 48, and a pair of grooves 42 communicating with the inlet bore 41. In the neutral position of the valve neither of the grooves 37, 38, is in commmication with its coacting exhaust grooves but if the sleeve 44 is displaced one end of the cylinder will be connected to exhaust and movement of the slide 12 occurs until after a movement equal to the movement of sleeve 44, the valve is restored to neutral. The sleeve 44 carries a nut segment engaging an axially fixed screw 53 on a shaft 55 which is rotated to impart the desired movement to the slide. The upper end of this shaft carries a piston engaging a bore 70 in the housing 34 moving with the slide. Exhaust oil from the valve 33 is used to lubricate parts of the gearing and for this purpose it passes through openings 51 into the housing 34 whence it passes into the chamber 70 through passage 74 and return pipe 76 into a gear box 59 and thence by pipe 77 to the reservoir. The shaft 55 extends into the gear box and carries reversing bevels 60, 61, driven from a power shaft 63 and controlled by a sliding clutch member 64. Shaft 55 may also be driven when the clutch is in neutral through bevel gearing 78 from a hand wheel. All the servo units are supplied from a header 84 leading to an accumulator 81 fed by a pump 82 driven through chain gearing 98, 95 from a motor 101, Fig. 9. The motor also drives the tool spindle 102 through clutch 106, shaft 105 and fourspeed gearing comprising two sliding pairs 114, 115, controlled from hand levers, and coacting with gears on a shaft 120 which is geared either directly or through an idler with a gear 122 driving a shaft 126. This shaft is connected by bevel gearing 129, 132, and gears 133 to the tool spindle 102. The hand controls for the screws of the servo mechanisms are operated by wheels 152.. 154 on the front of the machine the wheels 153, 154, being connected to their respective screw shafts by chains 164, 168, Fig. 9. The wheel 152 is associated with a dial plate graduated in thousands of an inch. In one example the wheel has one hundred graduations and works in conjunction with a linear scale 159 to indicate the total movement. Or the dial may have 250 divisions and the linear scale 159 graduated in quarter inches. Additional hand wheels are provided for operating the screws from the rear of the machine table. The power operation of the servo screws through the shafts 63 is associated with trip dogs for terminating the feed at the required points. In one form the shaft 63 of the tool-head mechanism carries a fluid motor 176 supplied from the accumulator 81 through a throttle valve 182, which is set by a hand operated cam to determine the flow to the motor 176. A dial 192 indicates the setting. Similar throttle mechanism is associated with the table and saddle feeds. In a modification, Fig. 12 the screw may be driven by an electric motor 195 whose speed is controlled by a rheostat 198 and dial mechanism 204. In another modification the shaft 63 is operated from the main motor through change speed gearing 210, 'Fig. 13 controlled by a cam 224 which is rotated by a hand wheel 226 provided with indicating mechanism. The clutch 64 is operated by a lever arm 231, Fig. 9 connected to a lever 233 having a trip lug 235 coacting with dogs 236 on the slide 12 and having three positions determined by a segment 238. At the end of the required movement the clutch is returned to neutral by one of the trip dogs. The clutch may also be moved either from the handle 240 or from a handle 243 on the front of the machine. Similar mechanism is provided for the table and saddle feeds. In a modification a single variable-speed motor 266 controls the drive of all the servo screws through the gearing shown in Fig. 10.