Patent GB-1005074-A (GB)
Title: Machine tool change-speed transmission
IPC: B23Q5/14
Filed: 1964-05-21
Abstract: 1,005,074. Change speed control. CINCINNATI MILLING MACHINE CO. May 21, 1964 [Sept. 23, 1963], No. 21134/64. Heading F2D. [Also in Division B3] Ratio shift meshing in a milling machine cutter spindle change speed gear 12 is facilitated by intermittently inching the gear input shaft 14 by supplying short energizing pulses to the driving motor 13 from a pulse generator operated in response to actuation of a rotary manual gear selector valve 59. Fluid pressure gear-shift servomotors A-H are selectively fed from a pump 31 through a main line 30 and a port 32 and passage 22 in the selector valve and exhausted through a port 24 and a bore 25 of an axially slidable plunger 26 constrained, by a pin 36 and slot 35, to rotate with the rotary selector valve barrel 21. In its spring-biased position shown, the plunger 26 connects the main line 30 also to a line 60 and a toothed member 38 is engaged by a fixed detent 37 to circumferentially locate the selector valve, whereas when it is rightwardly manually pulled by a knob 58 the passage 22 and the line 60 are exhausted. The pulse generator comprises a cylinder 61 having a plunger 63 slowly leftwardly moved by pressure in the line 60 entering the cylinders through a restriction 66, and rightwardly returned by a spring 64, the cylinder exhausting through a one-way valve 65 and the line 60. On the slow leftward movement of the plunger, ridges 67 thereon effect intermittent deflection of a spring-centred lever 68 to intermittently close contact pairs 70, 71 to provide pulses in a line 57. The pulses are shortened by an adjustable electrical or pneumatic timer 76 between the contacts 70, 71. In operation, the selector knob 58 can be axially moved or rotated only when the milling machine spindle is not powered. For this condition a switch SW1 is in its stop position shown, in which a power source 43 is connected and disconnected from lines 44, 45 respectively, and a de-energized solenoid valve 50 connects the main line 30 to a line 42 to actuate a pressure switch 54 to open contacts 55 to the driving motor 13, apply a brake 53 to the shaft 9 geared to the change speed gear input shaft 14, and lift a spring-loaded detent pin 39 and thereby permit rightward axial movement of the plunger 26. To change spindle speed the knob 58 is rightwardly pulled and rotated until a dial 59 indicates the desired speed. The line 60 is exhausted and the plunger 63 is spring shifted rightwardly to respectively open and close limit switch contacts 47, 79 and 74, 46. The closed contacts 74 connect the power source 43 through lines 75, 48 to energize the solenoid valve 50 to exhaust the line 42 to release the brake 53, close the contacts 55, and allow the pin 39 to be inwardly urged in detent readiness. On release of the knob 58 the plunger 26 reconnects the main line 30 to the passage 22 to actuate the gear shift servomotors and to the line 60 to slowly leftwardly move the plunger 63 to provide short pulses to the motor 13 through the switch SW1, line 44, closed contacts 46, contacts 70, timer 76, contacts 71, line 57 and closed contacts 55. Only when the plunger 63 is fully leftwardly moved do the contacts 74, 46 open and the contacts 47, 79 close. Opening the contacts 74 de-energizes the solenoid valve 50 to re-apply the brake 53 to await spindle operation or another speed change. To rotate the spindle, the switch SW1  is operated to connect the power source 43, through the line 45 and contact 79, to the contact 55 and to energize the solenoid valve 50, through the line 45 and contacts 47, to exhaust the line 42 to release the brake 53 and allow contact 55 to close and energize the motor 13.