Patent GB-565784-A (GB)
Title: Improvements in and relating to lathes and like machine tools
IPC: B23B13/00
Filed: 1943-02-22
Abstract: 565,784. Lathes; chucks. WARNER & SWASEY CO. Feb. 22, 1943, No. 2904. Convention date, Feb. 21, 1942. [Class 83 (iii)] In bar-stock feeding means for lathes &c., the chuck - actuating mechanism and the feeding mechanism are both operated alternately by an intermittently rotated shaft which is driven through a clutch under control of a cam disc on the shaft. In one form, for operating on relatively thin stock, the chuck collet 22, Fig. 1, is advanced into a bevelled cap 23 on the spindle 21, for gripping the stock 24, by a sleeve 25 and levers 29 expanded by a sliding cone 32. The cone is moved by a yoke 33 on a lever 36 having eccentric arcuate surfaces 38, 39 engaged by a roller 42 on a disc 40 attached to the intermittently rotated shaft 41 which is driven by a worm-wheel 44, Fig. 2, and worm 46 splined to a shaft 47. This shaft is axially slidable by means of a lever 54, against the pressure of a spring 50, to cause a clutch part 58 splined thereon to engage a clutch 59 driven by an electric motor 61, the shaft acting on the clutch part 58 through a flange 66 and spring pins 65 to produce a yielding engagement of the clutch. The end thrust of the worm 46 moves a sleeve 62 axially to operate mechanism for indicating the gripping pressure of the chuck jaws, as described in Specification 554,489. The lever 54 carries a roller 57 engaging the periphery of the disc 40 and is operated by a handle 56. Also mounted on the shaft 41 is a cam disc 45, Fig. 6, carrying a roller 69 engaging Geneva slots 73, 77 in arms 71, 75 which are geared together by toothed segments 72, these arms serving to rock a shaft 74 attached to a lever 78 connected by a link 81 to a stock-feeding slide 82, Fig. 1. A feeding sleeve 27 with spring fingers engaging the stock 24 is moved axially by the slide 82 through a yoke and a collar 84. In operation, the shaft 41 is normally stationary with the roller 57 lying in one of two diametrically opposed recesses 43 in the periphery of the disc 40, the clutch 59 disengaged, the collet 22 gripping the stock as shown in Fig. 1, and the feeding slide 82 in its rearward position. To feed the stock, the operator depresses the handle 56 momentarily, removing the roller 57 from the recess 43 and moving the shaft 47 to engage the clutch 59. The shaft 41 is thereupon rotated by the wormwheel 44, the disc 40 rotating anti-clockwise as viewed in Fig. 1 to cause the roller 42 to act on the surface 38 and rock the lever 36 clockwise to release the chuck jaws 22. Simultaneously, the roller 69, Fig. 6, which is rotating clockwise in this Figure, passes from the slot 73 to the slot 77 and so does not actuate the feeding slide 82 whilst the chuck is being opened, but when this has occurred, the roller 69 rocks the arm 75 to actuate the slide 82 and feed the stock through the required distance, which is determined by adjusting the pivot of the link 81 on the lever 78 by a screw 80. During the feeding movement, the roller 42 rides along the surface 38 without affecting the lever 36, since this surface has now become concentric with the axis of the shaft 41. The disc 40 has now completed half a revolution and the roller 57 drops into the next recess 43 to disengage the clutch 59 and allow the spring 60 to bring the parts to rest rapidly by engaging the clutch part 58 with a braking surface 68, Fig. 2. The operator may then check the length of stock fed, or if he maintains pressure on the handle 56 the disc 40 will continue to rotate, the roller 42 first rocking the lever 36 to close the chuck and then riding along the concentric surface 39 whilst the roller 69 passes into the slot 73 to rock the lever 78 and return the feed sleeve 27 to its retracted position. The operator then releases the handle 56 and the roller 57 enters the original recess 43 to bring the parts to rest. The roller 42 operates on the lever 36 at a short radius relatively to the lever pivot 35 during the chuck opening movement and at a long radius during closing, thus giving a motive force suitable to the conditions. In a modified feed for use with thick bar stock, the link 81 is connected to a slide 86, Fig. 13, having rotatably mounted therein a sleeve 89 carrying a flange 90 provided with axially projecting wedges 93 which are radially adjustable in T-slots on the flange to suit stock of different diameters.. The wedges pass through radial slots in a collar 104, 102 rotatably mounted in a housing 98 which is attached to the slide 86 with a limited motion allowed by slots and screws 96, 97 and is provided with radially adjustable jaw carriers 107. The carriers have backing rollers 108 for the wedges 93 whose other surfaces engage rollers 110 on the radially movable jaws 109. Adjustment of the carriers to suit stock of different diameters is effected by tangential right- and left-handed screws meshing with racks on oppositely disposed carriers. Motion of the housing 98 on its ways 20 is restrained by a friction strip therein pressed by springs against the ways. The rear end of the sleeve 89 engages by a spring ring 122 with a sleeve 120 carrying a collar 119 provided with wedges 93 similar to those on the flange 90 and acting on jaws 109 supported in a fixed housing 126. Axial motion of the collar 119 relatively to the housing 126 is limited by headed pins. In operation, the chuck is operated in the same manner as in the first example and after it has been opened the slide 86 is moved forwards by the link 81. The sleeve 120 is carried forward by the spring ring 122 to withdraw the wedges from the housing 126 to release the jaws 109 from the stock, after which the headed pins prevent further movement of the sleeve 120 and the spring connection 122 slips. Simultaneously, in its forward movement the sleeve 89 pushes the wedges 93 thereon into the housing 98 to cause the jaws 109 to grip the stock, after which the friction of the housing 98 on its ways is overcome and the housing and slide move forward to feed the stock. On completion of the feed, the chuck closes and the slide 86 is then retracted by the link 81, this motion first causing the wedges 93 to be withdrawn from the housing 98 and the other wedges 93 to be inserted into the housing 126. The stock is thus held by the axially stationary jaws in the housing 126, as well as by the chuck jaws, and the slide 86 returns to the starting position shown in Fig. 13, drawing the housing 98 therewith through the slots and screws 96, 97. The jaws in the housing 126 continue to grip the work during the machining operation.