Patent GB-410906-A (GB)
Title: Improvements in or relating to automatic lathes
IPC: B23B13/00
Filed: 1933-01-13
Abstract: 410,906. Lathes. HAHN, H., HAHN, 0., and TESSKY, K., (trading as INDEXWERKE HAHN & KOLB), Esslingen-on- Neckar, Germany. Jan. 13, 1933, No. 1164. Convention date, Jan. 20, 1932. [Class 83 (iii).] An automatic bar-feed mechanism for a hollow spindle lathe has means whereby, in order to compensate for differences in lengths of the stock bars, a push rod 11 serving to push the bars into the chuck is longitudinally displaceable in relation to its operating mechanism and is automatically fixed thereto according to the particular length of the stock bar. When the stock bar 84 has reached the position shown in Fig. 1 the guide tube 1 may swing around the pivot 2 for manually inserting a fresh stock bar in the forward end. During this movement a bevel wheel 3 on a shaft 4 rolls on a fixed bevel segment 6 thus rotating the shaft 4. This causes a stop 7 to act through a projection 8 to rotate an eccentric 9, so permitting a wedgebolt 12 to actuate clamping-dogs 10 to release the push-rod 11. The clamping-dog carrier is connected to a weight 18. The stock feed is arrested by a pivoted yoke 85, normally held aside by a spring bolt. A slide 13 on the guide tube 1 may be moved backward by a handle 38 and locked by a projection 15 to a fixed stop 14. During this movement the clamping-dog carrier 17 is moved backwards by a rod 16 and the weight 18 raised. The slide 13 also carries a pawl 20 which pushes back a rod 21 until a recess 22 in the rod is engaged and locked by a lever 23. When the parts are in this position a fresh stock bar can be pushed into the guide tube, the push rod 11 being moved back a distance which varies with the length of the stock bar. When the guide tube is swung back to the working position the shaft 4 is again rotated and the locking lever 23 is released whereupon the rod 21 is moved forward by a spring until a tappet 30 strikes the push-rod 11 which forces the stock bar against its stop. Further swinging movement of the guide tube causes the wedge bolt 12 to be moved upwards to clamp the push rod 11 and also causes the stop yoke 85 to be moved to inoperative position. Instead of the shaft 4 being operated automatically, it may be moved manually by a handle 40 secured to an extension of the shaft. In another modification, Fig. 8, the push-rod is moved automatically and the stock-bars are automatically fed from a magazine. In this form, when the stock-bar is used up, a lever 52 is automatically rocked, thus allowing a clutch to connect an auxiliary control shaft 55 with a constantly driven worm-wheel 99. The drive to the main control shaft 107 is at the same time interrupted. When the shaft 55 rotates a segmental lever 109 is rocked thus acting through a rope 114 to move back the dog carrier 17 and carriage 61. Further, a cam on the shaft 55 acts through a lever 69, Fig. 11, to slide the bottom 70 of the magazine and allow a fresh bar to drop into the channel 72 whereupon also the work stop 77 is moved by lever mechanism opposite the channel 72. A lever 32 on the shaft 76 rotates the eccentric 9 to release the clamping-dogs whereupon the push rod 11 is moved back behind the fresh stock bar by a spring 80. Further rotation of the shaft 76 withdraws the locking lever 23 from the rod 21 which is then moved to the right by its spring until the tappet 30 engages the push rod and causes it to feed the fresh bar against the work-stop. Finally the shaft 76 is reversed by the cam 104 and the push rod is clamped to the member 17, and the rope 114 is reversed to move the stock bar into the machine. After a revolution of the shaft 55 it is automatically declutched and the clutch of the main control shaft re-engaged. In another modification the clamping mechanism for adjusting the push rod to the length of the stock bar may be between the member 17 and the rope 114.