Patent GB-442818-A (GB)
Title: Improvement in stock feeding mechanism for lathes or like machine tools
IPC: B23B13/00
Filed: 1935-05-07
Abstract: 442,818. Feeding stock-bars in lathes. JONES & LAMSON MACHINE CO., Spring. field, Vermont, U.S.A. May 7,1935, No. 13466. Convention date, May 7, 1934. [Class 83 (iii)] In a feed mechanism for a bar stock lathe an actuating-mechanism is arranged so that it may be selectively positioned either to open the chuck and then to move gripping fingers to feed or retract the stock or else to leave the chuck closed and then to traverse the gripping fingers. The headstock 2 of a turret latch carries a ball-bearing spindle fitted with a collet chuck 7 operated by a tube 10 bearing at its rear end on a flanged collar 10<a>. The collet tube is moved to the right, Fig. 4, to close the chuck by pivoted fingers 16 actuated by a cam sleeve 20 housed in a casing 25 secured to the headstock. The casing has upper and lower bearings 26, 27 the bearing 26 carrying a rock sleeve 30 enclosing a rock shaft 31 journalled in the lower bearing and having a lever 34 pivoted at 33 to its upper end. The surfaces 37, 38 limit the pivotal movement of the lever. The sleeve 30 has extensions 40 carrying rollers which operate the cam sleeve 20 of the chuck. The lever 34 carries a plug 50 coacting with a similar plug 55 on the sleeve 30 so that when the lever is rocked from the Fig. 10 position to the Fig. 3 position the sleeve 30 is actuated to close the chuck. When the lever is in the full line position of Fig. 5 opposite movement of the lever causes the plug 50 to engage a projection 62 on a pivoted abutment and so open the chuck. After a predetermined movement and when the chuck is fully open the abutment rides off a cam piece 64 and thus frees the lever 34 for further movement. When the lever 34 is in the dotted position of Fig. 5, the plug 50 is lifted clear of the projection 62 so that the chuck opening movement of the sleeve 30 cannot be effected. The stock is supported in a stand comprising a pair of vertical rods 74, Fig. 2, carrying a body portion 72 spaced from the housing 25 by parallel guide bars 86. The stand carries adjustable work engaging rollers 76 and a pivoted retaining plate 81. The head also guides a movable rackbar 85. The bars 86 carry stock feeding means, Fig. 14, comprising a ball-bearing sleeve 100 carrying a scroll plate actuated by a bevel pinion 109 and serving to operate work engaging jaws 116, 117. Two of these jaws, diametrically opposed, are fitted with spring plungers 125 while the other two have adjustably fixed jaws 122. The jaws are able to slip over the work when the chuck is closed. The feed head 90 is actuated by the rack-bar 85 which is operated by the chuck lever 34. For this purpose the rack-bar coacts with a pivoted member 142, Fig. 15, controlled by a spring plunger 153 and by a second plunger 158 operated by an arm 160 on a, control shaft 161 carrying at its other end a lever 171 coacting with a screw 172 on the sleeve 30. When the chuck is closed the abutment screw is located so that the projection 144 of the member 142 engages the rack-bar and the feed head is movable to the left by the rack 85 but is not movable to the right. The rod 31 is connected to the rack-bar by links 180, 181 and lost-motion connection 1820. When the handle 34 is rocked through the arc a, Fig. 10, the chuck is opened and the lost-motion 1820 taken up, and the projection 172 removed from lever 171 so that the plunger 153 can engage the point 142 with the rack bar. Further movement of the lever through arc b then shifts rack bar to the right and feeds the work through the chuck. When the lever is returned through the arc b the rack bar is moved to the left but the feed head is not actuated. Thus by reciprocation of the lever through arc b any desired feed up to a stop 190 may be obtained after which the lever is moved through the arc a to close the chuck. When the feed head has been fed as far as possible to the right it is returned by oscillating the lever in its upper path (dotted in Fig. 5). The chuck sleeve is now not actuated to open the chuck and the projection 144 is maintained in engagement with the rack bar by the projection 172 so that the rack bar carries the feed head with it on its leftward movements but slips through it when moving to the right. By holding the lever 171 in the required position by hand the dog 144 may be held engaged with the rack with the chuck open so that the feed head and stock bar may be moved backwards if necessary.