Patent GB-250744-A (GB)
Title: Improvements in or relating to machines for making nut blanks
IPC: B23B41/00
Filed: 1925-03-30
Abstract: 250,744. Frayer, L. A. March 30, 1925. Combined turning and drilling machines; chucks; sockets. - In a machine for making nut blanks or like articles from bar stock, the bar :.s fed intermittently and is turned by chamfering and severing tools, and the drill, which is mounted in alignment with the work, is fed through a guide which serves also as a work stop and is reciprocated relatively to the drill to allow the escape of cuttings and to push the finished work-piece off the drill. The machine comprises two operative units mounted in a frame 15 and driven from a single electromotor 70 by a belt 71 passing over main shafts 72. Each unit comprises a feed tube 16, Fig. 12, through which the hexagonal stock bar 14 passes, the stock being gripped at the forward end by an interchangeable spring collet 16a and at the rear end by a gripper having balls 18 located in tapered pockets in a cage ring 17 so that the balls grip the stock on the forward movement but slide over it on the rear movement. The feed tube is reciprocated by a forked lever 20 which is trunnioned to a ring 21 to allow rotary movement of the stock. A sleeve 23 surrounding the feed tube carries a work-gripping collet 24 coacting with a tapered recess in the work-spindle 25, and the collet is normally closed by the centrifugal action of weights 27 connected to levers 29. The work-spindle, together with the sleeve and feed tube, rotated by a gear 30 driven from a pinion on the main shaft 72. The drill 31 is mounted in a spindle carried in a quill driven from the shaft 72 by a belt passing over the sprocket 34. The drill spindle is also supported in bearings in a non-rotary sleeve 35 actuated by a pinion 36. In order to eject the drill, the pinion 36 may be actuated by a hand wheel to engage an ejector rod 37 with the casing 38. The drill guide comprises a bushing mounted in a body 40 slidably adjusted on a hinged platen 48 by worm gearing 47. The drill guide is reciprocated during operation by means of a pinion 44 on a rock shaft 45 actuated through levers 84, 84<a> from a cam 74 on a cam shaft 73 driven by spur and worm gearing from the main shaft. The rock shaft 45 also carries a spiral gear 54 engaging a segment 53 on a shaft 52 on which is a lever 51 carrying the chamfering tool 50. The lever 51 is connected to its shaft bv a friction device and the correct movement of the chamfering tool is determined by adjustable stops on the platen 48. The cut-off tool 62 is mounted on a lever 63 similarly actuated from a spiral gear 66 on the rock-shaft. The reciprocation of the drill and the actuation of the chamfering and severing tools are all effected through lever mechanism from the cam 74. The stock feed is actuated from a cam groove 75 through levers 80, 81 and the chuck is opened by a cam 76 through further lever mechanism 83, 86. Clutches are incorporated in the cam shaft drives so that the two units can be operated either simultaneously or independently. Pumps 96 operated by belts 97 from the main shaft can be provided for circulating cooling liquid to the cutting-tools. In order to set the tools before operation a triangular block 67, Fig. 11, is substituted for the drill guide in the platen 48 the apex of the block serving as a guide for locating the cutting edges of the tools. In operation the drill guide, which acts as a feed stop, moves towards the stock while the chamfering and severing tools and the drill are withdrawn. The chuck is then opened, the stock fed to the stop and the chuck closed. The drill then moves into the cut and the chamfering and severing tools are also brought forward, the latter finishing its work just before the withdrawal of the drill. During the drilling, the drill guide moves back over the drill but on completion of the cut the chamfering and severing tools are withdrawn, and the drill guide moves forward over the returning drill thus forcibly stripping the finished blank. which passes on to a grating 98 which separates the chips from the nut blanks.