Patent GB-861335-A (GB)
Title: Temperature control of machine tool
IPC: B23Q11/14
Filed: 1959-08-19
Abstract: 861,335. Milling-machines; machine-tool details. CINCINNATI MILLING MACHINE CO. Aug. 19, 1959 [Dec. 17,1958], No. 28330/59. Class 83 (3). A machine - tool comprises means 106, 108, 112, for measuring the temperatures of a base portion 14 and of related portions 19, 20, 29, affected by the heat of working, and means for controlling the temperatures of the heated portions. In a four-spindle milling-machine, four workpieces 11 and a pattern 12 are supported by centres 22 adjustable by hand wheels 23 on a tailstock 17, adjustable vertically by a power-driven screw. The lower ends of the workpieces and pattern are supported on headstocks 21 carried by the tables 19 on the bed-plate 20. The cutters 31 are carried in the housing 29 movable angularly by linkage 35 controlled by an hydraulic device 34 on a saddle 27, movable vertically by further hydraulic means. The angular movements of the housing are controlled by a tracer 38, which also controls the motors driving the headstocks 21. The saddle is fed by an increment for each revolution of the headstocks. The pivotal support for the housing 29 consists of a shaft 32 mounted in a fixed bearing 33 and a floating bearing 26. The cutter spindles 41, Fig. 3, are housed in sleeves 44, and are rotated by a motor 58 driving through a chain 57, a shaft 48, bevel-gearing, and pinions 45. The machine is designed to function accurately when the housing 29 has a temperature 15 F. above that at a remote point 62 in the machine base, and when the temperatures of the bed-plate 20 and the tables 19 are equal to that at the point 62. The latter temperatures are controlled by the cutting-fluid flowing over the bed-plate and the tables during its passage from a pump 65, through a heat-exchanger 67 and a nozzle 68, back to the sump via a trough 69 containing a scavenging-screw 71. The housing 29 is cooled by fluid from the hydraulic system. From a sump 75 held at a temperature of 120 F. by an electric heater 76, the fluid is pumped through a heat-exchanger 81 to pipes 83, 84, in the housing 29, the pipes being perforated so that the housing walls are sprayed by the fluid, and to pipes 85 from which fluid is supplied through pipes 88 to the perforated gears 45 and through pipes 89, 90. to the spindle bearings. Thence the fluid flows through a pipe 96, an expandible sleeve 97 and a trough 98, back to the sump. The heatexchangers are connected to a cooling-water supply 145. The outlet of water from the exchanger 67 through a valve 110 is controlled by a thermostat 107 connected to the bulb 108 in the bed 20, and supplied with compressed-air from a source 103 via a thermostat 105 connected to the bulb 106 at the point 62. The outlet from the exchanger 81, through a valve 114, is controlled by a thermostat 111 connected to the bulb 112 in the housing 29. When the machine temperatures are not correct, either a light 119 is extinguished, or in a modification, the tools are automatically swung away from the work. In a further modification, the temperature of the housing may be controlled either relatively to the bed 20, instead of to the point 62, or according to the difference in temperature between the housing and the bed.