Patent GB-391456-A (GB)
Title: Improvements in and relating to hydraulically operated automatic lathes and like machine tools
IPC: B23Q11/00
Filed: 1931-10-27
Abstract: 391,456. Lathes. TRIGGS, W. W., 57, Lincoln's Inn Fields, London.-(Warner & Swasey Co. ; 5701, Carnegie Avenue, Cleveland, Ohio, U.S.A.) Oct. 27, 1931, No. 29739. [Class 83 (iii).] In an automatic lathe or like machine tool wherein the tool or work supporting slide is moved hydraulically relatively to the rotary work or tool-supporting spindle, the hydraulic means including a motor and control valve with provision for automatically varying the slide movements and the spindle speed, means are provided for ensuring the constancy of a selected relation between the feed motion of the slide and the spindle speed which include a connection between the spindle, slide, and valve. The connection preferably includes a differential mechanism. Feed-motions, tool and saddle.- The lathe comprises a bed 20, Fig. 1, carrying a headstock 23, turret slide 22, and compound transverse front and rear slides 27 which are controlled by the feeding movements of the turret slide. The headstock is axially adjustable on the bed and carries a gear splined to a control shaft 31 to permit the adjustment. The turret slide 22 is connected by a pin 22a, Fig. 5, to a hydraulic cylinder 43 whose pistonrod 44 is attached to the bed 20, the effective area at the free end of the piston being double that at the rod side. The fluid is controlled by a valve 53 in a casing 52, Figs. 1 and 18, fitted with a supply pipe 45 leading from a pump 204 (not shown), driven by a motor 205 (not shown) and with an exhaust pipe 46, a relief valve 45a being provided. Pipes 47, 48 lead to the piston rod 44 and thence by passages 49, 50 in the rod to opposite sides of the piston. The valve is so constructed that to give a rapid forward feed to the slide 22, fluid passes from the pump to the pipe 48, as shown in Fig. 18, and the exhaust from the other side of the piston passes through the pipe 47 and the valve to the pipe 48 so that the pump will only be required to supply the same quantity of fluid as is required for a rapid withdrawal of the slide at the same speed. For this purpose, the valve 53 will be in its extreme left-hand position and the pump then supplies the passage 49 through the pipe 47 and the passage 50 is connected through the valve to exhaust. A slow cutting feed is imparted to the slide when the piston 53c of the valve moves sufficiently to the left to uncover the passage 113 slightly and to connect the pipe 47 to exhaust through passages 111, 115. The valve is connected by a lostmotion coupling 99, Figs. 21 and 22, to a slide 72 carried by a housing 71 secured to the bed 20. A spur gear 78 and a worm wheel 79, Figs. 22 and 24, are secured to the same axle and are journalled in an opening 72a in the slide, the spur gear meshing constantly with a rack 76 secured to the turret slide 22 and the worm wheel being engageable by a drop worm 81 mounted in a bracket 83 which is pivoted on a driving shaft 40. The shaft 40 is driven at an automatically variable speed from the lathe spindle 24 and has splined thereon a gear 85 which drives the worm 81 continuously whilst the spindle rotates. In operation, the valve 53 is moved to starting position by oscillating a hand-lever 73, Fig. 22, from the stop position A to the position B, causing the slide 22 to be fed rapidly towards the headstock 23 until a cam 63, Fig. 21, on an indexable drum 62 moving axially with the slide, encounters a lever 87 pivoted by a pin and slot 88 to the housing 71. This oscillates a lever 91, pivoted at 92 to the housing, to actuate a spring plunger 93 attached to the bracket 83 and causes the worm 81 to be engaged with the wheel 79. The rack 76 then rotates the gears 78, 79 faster than they are rotated by the worm, thus causing their axle to be displaced and moving the slide 72 and valve 53 to the slow-feeding position corresponding to position C of the lever 73. When the turret attains its cutting speed, as determined by the speed of rotation of the shaft 40 and worm 81, the gears 78, 79 rotate on a stationary axis, but should the speed of the turret slide tend to vary from this cutting speed, the axis will be displaced and the valve 53 will be moved to restore the constant rate of feed. The cutting feed continues until an extension 55, Fig. 5, of the cylinder 43 engages a stop 56 on an indexable drum 57, thereby stopping the feed positively. The continued rotation of the worm 81 then rolls the gear 78 on the stationary rack 76 and moves the lever 73 beyond the rapid feed position B to a position D, thus causing a dwell in the feed and allowing all spring of the cutting tools to be taken up. A spring 99a in the lost-motion coupling 99 allows the lever to move beyond position B although the valve 53 is in the extreme position for rapid forward feed. After the predetermined dwell has elapsed, a spring pin 100, Fig. 21, on the slide 72 engages a cam 64 on the drum 62 and depresses a plunger 102, causing a cam surface 102a thereon, Fig. 24, to displace a trigger 97 and release the bracket 83, allowing the worm 81 to drop out of engagement with the wheel 79. Simultaneously, a cam surface 102b on the plunger 102 engages a trigger 107 and removes it from the end of a spring plunger 106 located in the housing 71. The plunger 106 then moves the slide 72 rapidly to the left, causing the lever 73 to assume position E for rapid withdrawal of the turret. The spring 106a of the plunger 106 is compressed by a pin 105 attached to the slide 72 when the latter is moved to the right for the forward feed and is locked by the trigger 107 until released by the plunger 102. A projection 103, Fig. 21, on the slide 72 is adapted to depress the plunger 102 if the cam 64 should fail to act, and the plunger is of sufficient width to engage the pin 100 throughout a considerable range of adjustment of the cam 64, according to the required amount of dwell of the turret. If the plunger 102 is depressed by the projection 103, instead of by the cam 64, the plunger 106 is moved inwards by the pin 105 beyond the trigger 107 so that when the worm drops the trigger returns into position to engage the plunger 106 and prevents it from moving the slide 72 to the left. The valve 53 is therefore not moved to the rapid return position and the turret remains in its forward position to warn the operator that the cam 64 is not in proper adjustment. The worm 81 may be dropped at any time by manipulation of the trigger 97 through a handle 98, and may be engaged with the wheel 79 by manipulating the lever 91 through a handle 110. On approaching the end of its rearward movement, the turret slide moves the slide 72 to the right, for the rapid forward feed of the next cycle, through a dog 108 thereon pressed by a spring 108a which is stronger than the spring 106a. A lever 109 lies in the path of the dog to delay its action until the lever has been moved from operative position by a cam 65, Fig. 21, on the drum 62. The cam 65 may be omitted from the final side of the drum 62 to prevent the turret slide from being started on a new series of cycles, the valve 53 then remaining in the withdrawal position until the pressure in the cylinder 43 is relieved by the operator or until a new series of cycles is initiated by moving lever 73 to the rapid forward position. The cam drum 62 and the stop drum 57 are indexed for each cycle of movements of the turret slide by a shaft 61, Fig. 5, connected by a chain and sprocket 66 to a shaft splined to the drum 62 and by gearing 60 to the drum 57. A lever 169, pivoted beneath the cylinder 43 engages a spiral cam 168 on the shaft 61 towards the end of the rearward movement of the turret slide 22 to index the shaft 61, the cam 168 having as many grooves as there are stations on the turret 25 and the lever being pressed by a spring 170 so as to ride over the cam during forward movement of the slide. Speed-controlling mechanism; brakes, applications of; clutch-operating mechanism. The headstock spindle 24, Figs. 1 and 16, is driven from an electric motor 191 through a main shaft 189, clutch 188, and change-gear shafts 185, 186, giving six speeds to the spindle. The speeds are controlled by two clutches 185a, 186a, operated by fluid cylinders 184, 183 respectively and an over-running clutch. The main clutch 188 is operated by a fluid cylinder 187, and a stationary brake 190 is provided to stop rotation of the spindle immediately the clutch is thrown out. The cylinders 183, 184, 187 are operated by valves in a chest 172 which are controlled bv cams 173 .. 176 on the indexable shaft 61. The shaft 40, which drives the worm for determining the speed of the cutting feed of the turret slide, is driven from the spindle 24 through a gear train 30, splined shaft 31, and change-speed gear 37 controlled by a sliding key 41 actuated by a fluid cylinder 194 and yoke 195. The cylinder 194 is controlled by a valve in the chest 172 operated by a cam 177 having as many rises as there are stations in the turret 25, and the position of the key 41 for each station is determined by the piston-rod engaging one of a series of stops in an indexable drum 196. The drum is indexed by a Geneva motion 197 and a gear train 197a. The cam 176 which controls the main clutch 188 normallv throws out the clutch to stop the spindle 24 after a series of cycles (i.e. when the turret 25 has passed through all its stations), but it may be rendered inoperative by axial movement thereof to allow the spindle to rotate continuously for uninterrupted operation of the lathe. Axial movement of the cam is caused by a hand-lever 199, Figs. 7 and 9, movable in aT-slot 202 and fulcrumed in a slot 20a of the machine frame 20. A slidable rod 200 is pivoted to the lever 199 and carries an arm 203 passing under the boss of the cam 176. As shown in Figs. 7 and 9, the arm 203 is out of alignment with the stem 181 of the valve for the cylinder 187 and the spindle 24 is at rest. Movement of the lever 199 along the slot 202 moves the