GB945680A - Improvements in or relating to multi-spindle automatic machine tools - Google Patents

Abstract

945,680. Automatic lathes; bar feeds. BIRFIELD ENGINEERING Ltd. May 30, 1961 [May 30, 1960], No. 18980/60. Headings B3B and B3T. Control apparatus for a multispindle bar machine automatically feeds a new bar to the " empty " spindle when the slug end is too short to reach the stock stop. A combination of electric and pneumatic circuitry is used. The machine comprises a rotary indexing drum 2, Fig. 1, with spindles such as 5. A main cam-shaft 3 controls indexing of the drum and feed of the tools and also operation of the collet 4 at the parting-off station. When the collet is opened a conventional reciprocating gripper device operates to feed the bar against a stock stop 6, Fig. 3. During machining the stock stop is pivoted aside on the shaft 29 but in the stock feed operation below, only the section 32 is moved by a pneumatic cylinder 34. A stock reel 7, Fig. 4, is positioned behind the drum 2 for indexing movement therewith and guides 8 therein are aligned with the machine spindles. Stock bars 19 are positioned on a ramp 14 adjacent the position or station in alignment with the parting off station of the machine. Five spaced lifting cylinders 20 lift the lowest bar over the step 18 to charge the reel. A pusher 23, Fig. 1, attached to a chain 26 driven by an electric motor 25, moves the bar 19 into a spindle 5. A separate " short-feed " chain 36 driven through an overload clutch is employed to move the pusher to its final feed position. The control means includes a switch-operating cam-shaft 55 driven from the main cam-shaft 3 and a control gear cabinet 62 with switches for automatic or manual operation. If the bar at the parting-off station is exhausted and does not reach the stock-stop 6 a switch therein remains closed and the automatic change can take place if the control box 62 is so set. A main camshaft control lever 73 is moved to stop the camshaft 3 so that normal machine operation is halted and cylinder 34 swings part of the stockstop away so that the slug end may be ejected. A timing cylinder with a flow regulator then comes into operation prior to the lifting of a fresh bar over the step 18 and into the reel behind the slug-end. The timing cylinder ensures that the bar is in position in the reel before motor 25, driving the pusher, is operated. When the leading end of the fresh bar 19 reaches a set position forward of the stock reel a switch is tripped which starts the motion of the short feed chain 36 which carries on the feed of the bar up to a position where the end can be faced at the start of a fresh cycle of operations. Motor 25 is then reversed to return the pusher back to its rearward position and lever 73 is finally moved to start up the main cam-shaft.