Patent GB-691919-A (GB)
Title: Single spindle automatic lathe
Inventor: MILLER CARROLL ELLIS
IPC: B23B7/12
Filed: 1950-04-17
Abstract: 691,919. Automatic lathes. CONE AUTOMATIC MACHINE CO., Inc. April 17, 1950, No. 9384/50. Class 83 (iii). A single spindle automatic lathe comprises a rotary work-carrying spindle, an indexing tool-carrying turret provided with a number of tool supports at different angular positions arranged for successive operative index positions with relation to work carried by said spindle, means for indexing said turret, means for starting said indexing means, and mechanism carried by said turret for stopping the indexing means when the index station corresponding with the work spindle has been reached and said indexing mechanism has completed its cycle of operations. The automatic turret lathe is similar in general construction to that described in Specification 618,417, and is provided with a single work spindle 6, a tool-turret 11 with tool-slides 15 and feed means which couple up with a slide, when brought into the working position. Similarly an overhead cam-shaft 5 is provided which may be driven at different speeds for working and idle movements, the driving arrangement for this is, however, not described in the present Specification. Indexing.-The rear of the turret stem 34, Fig. 3, has secured thereto a Geneva wheel 30 with slots 31 into which engage intermittently the end of an indexing arm 32 keyed to a shaft 33. The latter is driven for the indexing movement from a cross-shaft 42, Fig. 6, which is driven continuously by a sprocket-wheel and chain from an electric motor 48. A clutch 43 serves to engage the drive from the crossshaft to a worm 41 which drives a worm-wheel 40 secured to the shaft 33. A further clutch 50, with its operating lever linked by a rod 60 to the operating lever for clutch 43, operates as a brake. The cross-shaft 42 may be turned by hand through this clutch in reverse direction to set up the machine on which a switch 57 is operated to disconnect the power supply to the whole machine. A pair of roller-ended bellcrank levers 63, 64, connected to the rod 60 through lugs 59 and forked extremities 61, 62 on the levers, Fig. 7b, are used to control the clutch operation. The control members 70, Figs. 3 and 10, for this purpose, are carried on the ends of spindles 71, one for each turret slide, journalled in the Geneva plate 30 intermediate each indexing slot. On the rear end of the spindles dogs 80 and 72 are carried, the former are arranged in the plane of a cam-plate 81 Fig. 10, carried by the indexing arm 32 and the latter are spaced to lie in different planes matching the planes in which adjustable rings 74 carrying dogs 73 are arranged on a hub 75, driven from cam-shaft 5, which rotates freely on the end of shaft 33. The outward ends of spindles 71 carry crank-arms 85 with pins 86 and anchor springs 87 which bias the crank-arms into an operative or inoperative position determined by the flats on the sides of the crank-arm and stop-members 90. When turned to the inoperative position the turret will continue to index past this position and by this means one or more turret slide stations may be " jumped." Immediately before an indexing operation of the turret the clutch 43 is disengaged and control levers 63, 64 are in the position of Fig. 7b with roller 66 raised. Control member 70 underlies roller 66 and when the appropritate lobe or dog 73 on bush 75 (rotated from the main cam-shaft 5) strikes the dog 72, shaft 71 is rotated in an anticlockwise direction and roller 65 is raised, roller 66 drops, moving drag-link 60 to engage clutch 43 and thus setting shaft 33 and the indexing arm 32 rotating. Cam 81, Fig. 7a, is thus brought into action against dog 80 and shaft 71 (occupying the top position) is held against clockwise rotation induced by its bias spring, it remains thus as during the indexing it moves out of position with the Geneva wheel 30. When the succeeding shaft 71 comes up to the top position its bias spring holds the member 70 in the right-hand " dotted " position, Fig. 7b, and the roller 66 is lifted to throw out the clutch 43 and engage the brake to bring the indexing mechanism once more to rest. Locking and transverse feed (taper turning).- The turret is locked in indexed position by a finger 101, Fig. 10, engaging one of a series of notches 103 formed in the periphery of the Geneva wheel 30. The finger is pressed in the locking direction by a leaf-spring 108 and is pivoted at its lower end to a lever 100 which is in turn pivoted at 104 and has a roller 106 engaging a cam 107 carried on the shaft 33. The upper end of the finger 101 is guided by a pivoted slide-block 111 so that it is capable of limited rotative movement with the lever 100. The fulcrum 104 is arranged on a vertical slide 112, Fig. 5, connected by a link 113 to a bell-crank 115 which may be operated by a cam 118 arranged on cam drum 119 carried by the main cam-shaft 5. The turret may thus be rocked in the locked position for effecting an undercut operation on the work or for taper turning. This matter forms the subject of Specification 691,959. Tool-slide operation.-As each tool-slide is brought into its operative position an auxiliary slide member 152, Figs. 3, 6 and 16, is brought into engagement with a roller 150 on the end of a feed control lever 138. This lever is fulcrumed at 137 to a slide-block 136 adapted to move parallel to the machine axis on fixed guideways. A roller 135 carried by this slide engages a cam groove 131 in a cam member 130 secured to the shaft 33. This mechanism effects the rapid approach and return of the operative tool-slide but remains at rest during the slow tool feed. The upper end of the lever 138 is attached by an adjustable link to a further slide-block 141 carried on a guide-bar 142 and with a supporting fork 143 sliding along the cam-shaft 5. The slide 141 is provided with a sloping segmental cam face 144 adapted to be contacted at suitable times by cam followers 145 which are selectively positionable around the periphery of a drum 146 on the control shaft 5. A stop 148 limits the right-hand movement of the slide and the position of the selective roller 145 in conjunction with the cam-face 144 determines the basic feed movement transmitted to the end 150 of the lever 138. The auxiliary slide 152 is connected by a pin 176 to a bar 177, the forward end of which is provided with cam follower roll 178 adapted to ride in an angle slot 179 in a guide plate 180, Fig. 16, secured to the turret. Above the follower roll on the bar a slide-block 183 is secured adapted to engage a groove 184 cut across the lower face of a disc 185. This disc is rotatably adjustable in a mounting on a slide 190 which is secured by bolts 195 to the toolslide proper 15. Means are provided for the sensitive adjustment of the disc 185 and a combination of feed movements may be given to the tool slide in a manner similar to that described in Specification 634,518. Specification 691,958 also is referred to.