Patent GB-475960-A (GB)
Title: Improvements in speed changing devices for metal cutting or other machine tools
IPC: B23Q5/18
Filed: 1936-02-26
Abstract: 475,960. Driving - gear for lathes &c. WARNER & SWASEY CO. Feb. 26, 1936, No. 5737. Convention date, Feb. 26, 1935. [Class 83 (iii)] [Also in Group XXIV] A metal-cutting or other machine tool such as a lathe has the spindle or other part driven through a driving clutch and change-speed gearing including a part movable in a rotary direction to preset it for a certain speed and in an axial direction to obtain the speed with a single control handle which is moved in one plane to control the driving clutch, and in another plane to control the speed selecting and changing device. The spindle 32 is driven through a two-speed motor (not shown) and a pulley 33, Fig. 14, on a shaft 34, carrying multi-plate clutches 35 for forward or reverse drive operated by a splined member 36. Gears 38, 37 drive in 'opposite directions gears 42, 39 mounted on a countershaft 40 which is geared by a sliding cluster 44 to another shaft 49 driving through a gear 48 a loose sleeve 51 on the spindle connected by either of gears 50, 52 to a sliding gear pair 53, 55 on a shaft 54. A second pair 57, 56 on the shaft 54 coact with gears 58, 59 on the spindle, the train thus giving 12 spindle speeds or, with a two-speed motor, 24 spindle speeds. The clutch 36 is operated by a yoke 60, Fig. 4, through a rod 61 and lever arm 62 on a shaft 63. The three-step gear cluster is shifted by a yoke 64 through levers 65, 67 and shaft 66. The gear pair 53, 55 is shifted by a lever 68 loose on the shaft 66 and the gear pair 56, 57 is shifted by a lever 70 on a shaft 71 connected through lever 73, and link 74 to an arm 75. Levers 67, 68 and the arm 75 carry pins 76 ... 78 respectively which lie between a pair of spools 79, 79a movable along a shaft 80. The spools, Fig. 13, have projections of varying length so that the pins are adjusted to various positions by angular adjustment of the spools, the angular positions being determined by a series of thirteen depressions 86. These depressions are engaged by forks mounted on sleeves 91, 93 respectively. In their separated position the spools may be given a stop-by-step movement by means of a dial 81, to preselect the gear next required. The axial movement of the spools to permit their being indexed is effected from an operating lever 104 through lever mechanism. The lever 104 extends from a hub 103 connected by a lever 101 to a disc 98 on a shaft 97 which through an equalizing bar imparts equal inward or outward movement to the spools. The lever 104 is retained in its upper position by a friction shoe. Downward movement of this lever rocks downwardly a block 106 and compresses a spring 107. The lever 104 may also be rocked horizontally to control the clutches 35 for forward or reverse spindle rotation. When these clutches are in neutral position the spring 107 can move block 106 upwardly to engage tongue 106a with a stationary block and lock the control lever in neutral. A locking pin 109 coacts with a two part locking lever 110, 111, the latter part having a locking tooth engaging in one of two depressions in an extension of the lever 70 controlling the gear pair 57, and a second locking tooth 111b engaging in one of three recesses in an extension of lever 65 controlling the cluster 44. When the control lever 104 is in neutral position, locking pin 109 enters a recess 63b and a spring 110b rocks the lever 110, 111 and the locking teeth are thus disengaged. After the gears are shifted by downward movement of control lever 104, the lever is moved horizontally to engage forward or reverse clutch. The recess 63b is then out of register with its pin and the latter re-engages the locking teeth. Shaft 40 carries a brake drum 114 engaged by a shoe 115, Fig. 15, connected to a pivoted link 116 having a cam projection coacting with a similar projection on a rod 118 carrying a gear segment 119 meshing with a rack on the sleeve which carries the yoke 60. When the control lever 104 is moved to neutral position, the rod 118 is rocked to depress the link 116 and apply the brake. The shaft 83 operated by the speed selecting dial passes through a sleeve carrying a cam 120a which depresses a rod 122 by an amount depending directly on the selected speed, thus lowering one end of the brake shoe and regulating braking force in direct proportion to the operating speed of the spindle. In order to rotate the cam 120a a bevel gear 83b on shaft 83 drives a shaft 83d, Fig. 16a, carrying a pair of splined stepped spools 83e, 83f. When the control lever 104 is raised to move the spools 79, 79a outwardly, the spools 83e, 83f are also moved outwardly endwise by lever mechanism. After selecting the speed the spools are moved inwards again into engagement with a pin on a rack bar 120c which rotates the cam 120a and thus positions it in accordance with the speed setting to vary the braking resistance. The turning of the speed dial and the spools may be effected automatically under the control of lever 104. The shaft 34 has a pulley 123 driving a pulley 125, Fig. 2, geared to a toothed clutch member coacting with a toothed star wheel 132a on the shaft 80. When the spools 79, 79a are moved outwards by the upward movement of control lever 104thesleeve 93 actuates a rod 135 to engage the clutch members to drive the shaft 80 and rotate the spools 79, 79a and the dial 81 by power. In a modification, three pairs of spools, one for each gear cluster, is employed. The speed dial 81 is mounted on a shaft geared to shafts 141a, 142a rotating synchronously with the dial and a shaft 143a rotating at twice the dial speed. The shafts 141a, 142a each carry a pair of spools controlling the gear pairs 53, 56 respectively while shaft 143a has spools controlling the gear cluster 44. The spools are operated by flanged members sliding on a shaft 140 and actuated by racks operated by meshing gear segments 149, actuated through shaft 151, rod 101a and hub 103a from a control handle 104a. Hydraulic power means may be provided for moving the spools endwise and shifting the gears. When the control lever 104b, Fig. 26, is raised, a control valve 171 is set to admit fluid to a cylinder 166 and rock a lever 168 actuating the spools, and when the lever is moved downwards the valve is shifted so that the spools are moved inwardly to shift the gears. The power means for indexing the spools as described above may be used in conjunction with this hydraulic mechanism for effecting the endwise movement. The projections of the spools are so designed that the pins operating the gear cones are shifted in predetermined sequence in such a way that the gear train is not broken at more than one place at the same time.