Patent GB-597784-A (GB)
Title: Improvements in automatic lathes and like machine tools
IPC: B23B9/02
Filed: 1945-08-27
Abstract: 597,784. Lathes. WICKMAN, Ltd., A. C. Aug. 27, 1945, No. 21930. Convention date, Nov. 8, 1944. [Class 83 (iii)] A multi-spindle lathe or like machine in which the work spindles are successively indexed to a cut-off position comprises a cut-off tool slide, a bar-stop and a linkage for advancing and retracting said tool slide, including a movable fulcrum, an element pivotally mounted on said fulcrum, another linkage for moving said bar-stop to " in " and " out " positions, means for operating said linkages in timed relationship so that said tool slide is advanced as said bar-stop is moved to its out " position - and retracted as said bar-stop is moved to its " in " position, and means operated by said bar-stop mechanism to shift said fulcrum in said tool-slide' linkage to increase the tool-slide movement effected by said tool-slide linkage. The slide 20, Fig. 3, carrying the cutting-off tool 22, moves on guideways 19 in a bracket secured to the machine frame. The slide is advanced and retracted by a lever 25 keyed to a sleeve 26 which engages the forward end of a yoke 24 adjusted to control the tool position by a micrometer screw 23. A compression spring 28 maintains the end of the lever against the forward portion of the yoke and thus takes up backlash. Rotatable within the sleeve 26 is a shaft 31 which carries the axially adjustable stock-stop 30, Fig. 1. The shaft 31 and the sleeve 26 are oscillated from a cam disc 40 on a shaft 41 driven in timed relation with the turret indexing drive of the machine. The cam groove 43 controls the movements of a follower 53 carried by a lever 50 pivoted at 51. This lever is connected through a sliding yoke block 56 to a vertical rack 54 having a link 58 at its upper end secured to a lever 57 keyed to the shaft 31. The stock-stop is thus moved over, to gauge the length of stock, and moved away again, at intervals determined by the form of the cam-track 43, in order that the cutting-off tool may operate. A further camtrack 42 disposed on the opposite face of the disc 40 controls the movements of a follower 72 carried by a lever 70. This lever is pivoted on a pin 63 which is integral with, and eccentrically disposed in relation to, a spindle having fixed thereon a pinion 60 meshing with the rack 54. Thus, in addition to the oscillation of the lever 70 due to the cam-track 42, a further reciprocation is superimposed on the lever in accordance with the movements of the stock-stop linkage, this reciprocation giving a high-speed feed and return to the cutting tool-slide 20. Movements of the lever 70 are transmitted to the tool-slide through an arcuate slot 74 carrying an adjustable block 75 through a link 79 pivoted at one end to the block and at the other end to a lever 78 keyed to the sleeve 26 which carries the operating lever 25 for the tool-slide. With the tool in its innermost position, the linkage is as shown in Fig. 5, and the block 75 may be adjusted to alter the working stroke of the tool, controlled by the cam groove 42, without affecting the position of the tool, since the arcuate groove in this condition intersects at right angles the line joining the pivots at 60 and 80. Specification 430,243 is referred to.