Patent GB-552716-A (GB)
Title: Improvements in metal cutting or other machine tools
IPC: B23Q5/18
Filed: 1941-09-19
Abstract: 552,716. Lathes. WARNER & SWASEY CO. Sept. 19, 1941, No. 12131. Convention date, Nov. 20, 1940. [Class 83 (iii)] [Also in Group XXIV] A lathe &c. has the spindle or other movable part driven at different speeds through change speed gearing controlled by selecting or pre-selecting means including mechanical means such as indexible spools, the indexing of the spools being power-actuated under electrical control. The work spindle is driven from a main pulley 27, Fig. 2, which drives a shaft 28 carrying a friction clutch 29 engageable either with a gear 32 to drive a gear 37 on a shaft 34 in a forward direction or with a gear 33 to drive a gear 36 through an idler 35 in reverse direction. The shaft 34 carries a triple gear 38 ... 40 coacting with gears 41 ... 43 to impart a three speed drive to a shaft 44 which drives a loose double gear sleeve 45 coacting with gears 49, 50 on a shaft 48 which carries a further double gear 51, 52 engageable with gears 53, 54 or the spindle 26. Twelve spindle speeds are thus obtained in either direction. A single control lever 55 is movable in both horizontal and vertical planes The horizontal movement rocks the housing 56 which has a part 61 connected by a lever 63 to the yoke which operates the clutch 29, forward, reverse, and neutral positions being associated with the horizontal lever movement. The indexible means for shifting the gears comprise a pair of axially movable spools 66, 67 mounted on a shaft 68 and having co-operating pairs of projections engaged by pins 86, 94, 98 connected to the various gear shifters. When the lever 55 is moved vertically a bell-crank 73, 76 operates a pair of sleeves connected by an equalizer bar 84 to impart axial movement to the spools. The indexing of the spools to preselect the various gears is effected by an electric motor 105a controlled by switches which may be set by the operator so that a predetermined succession of speeds may be obtained for successive steps in a work cycle which may be repeated without further settings. The motor 105a, Fig. 3, drives a gear 108 on a shaft 109 connectable through a member 111 to an enlargement on the spool shaft 68 by friction shoes 112. A ratchet 113 in this train is engaged by a pawl 114 controlled by a solenoid 116, the part 117 of which normally disengages the pawl after one revolution of the shaft 68. To stop the indexing movement after different fractional revolutions a series of solenoids 119A ... L, Fig. 14a, one for each speed, are spaced around a one toothed disc 120 on the shaft 68. When any solenoid is actuated its plunger projects into the path of the tooth 121 to arrest the spools in the required position and the solenoids are energized in any required sequence by a switch 129, Fig. 14, and a series of push button switches 130 arranged on a panel 131 in a number of rows corresponding to the number of steps in a cycle (six in the form shown). When any switch is depressed a contact portion bridges contacts 134, 135. To restore all the switches to their normal outer position when the set-up is to be altered a button 141 associated with each row operates a bar provided with camming portions arranged to return any switch which has been depressed. The switch 129 includes a bar 144, contacts 145 corresponding in number to the steps of the cycle and movable bridging contact 146. The latter is actuated by the control lever 55. For this purpose the lever arm 76 of the spool-separating mechanism is connected by lever mechanism 148, 150 to a ratchet 153 on a shaft 154 which at each downward movement of the control lever imparts axial movement to a sleeve 156 to move the bridging contact 146 from one contact 145 to the next. The shaft 154 carries a dial 159 which gives a visual indication of the step in the work cycle which is being or is about to be carried out. When the cycle has been completed, the shaft 154 is restored by a spring, which is rendered effective by an additional movement of the control lever. The control lever movement also effects the temporary closing of the circuit of solenoid 116. For this purpose the lever 148, Fig. 3, actuates a switch 176 so that at each actuation of the control lever the plunger 117 is retracted to allow one revolution of the part 113. One end of all the solenoids 119A ... L, Fig. 14a, is connected to the negative line 199 while the other ends are connected to the various contact bars 135. The contact members 134 of any particular row are all connected to a corresponding contact 145, Fig. 14, and through the bridging contact 146 and bar 144 to the positive line. In operation, the operator preselects the required speeds for the various cycle steps, by actuation of the appropriate push buttons, one in each row. The hand wheel 163 is then rotated to position a sleeve 166 so that it causes the spring return of shaft 154 when the desired number of cycle steps have been performed. The main switch 182 is now closed and with the bridging contact 146 on its first contact 145 the proper solenoid for the speed desired for the first cycle step will be energized. This projects the plunger of, say, solenoid 119J, Fig. 14a. The lever 55 is then raised first partially to separate the spools and then fully to close switch 174, withdraw plunger 117 of solenoid 116, and allow one rotation of the part 111. Generally the disc 120 on the spool shaft is stopped by its plunger before the completion of a revolution and the clutch between the parts 110, 111 then slips. The spools are now indexed. Lowering of the control lever brings the spools together and shifts the gears to obtain the speed for the first step. The same lever movement moves the bridging contact 146 onto the next contact corresponding to the second step. The operator now moves control lever horizontally to engage the main driving clutch for either forward or reverse rotation. At the completion of the first step the control lever is again put in neutral, then raised to separate the spools and index them to the position corresponding to the next speed and so on for all the cycle steps. In a modification only a single row of switches may be employed and the step-by-step switch dispensed with. In this case the operator preselects or selects each different speed for the different steps either while one step is in progress or just before a step is initiated. The gearing described may be applied to operate parts other than the work-spindle such as the slide rest, cross slide or turret saddle.