Patent GB-190123830-A (GB)
Title: Improvements in Automatic Machines for making Metal Screws and other Analogous Articles.
Filed: 1901-11-23
Granted: 1902-06-05
Abstract: 23,830. Lake, H. H., [Waltham Screw Co.]. Nov. 23. Lathes; milling; screwing.- An automatic machine for miking finished metal screws and other analogous articles from wire has a headstock 30, Fig. 1, tailstock 112, and cam shaft 19 mounted on a bed 10. The cam shaft is driven by worm gearing 17 and a cone pulley 16. The main spindle 34, Fig. 5, has a fast pulley 40 and loose pulleys 43, 44, and can be driven in opposite directions by open and crossed belts 41, 42. The belt forks 68, 69 are freely pivoted on a rock-shaft 59, and are pulled by springs 70, 71 to move the belts on to the loose pulleys. The rock-shaft is operated by an arm 60 on it engaging a cam 63, and has secured to it arms to move the belt forks against the action of their springs. The cam 63 is shaped first to move the open belt on to the fast pulley, and then back to the loose pulley, while the crossed belt is moved to the fast pulley, and then to allow both belts to run on the loose pulleys, the spindle remaining at re-t. The feeding of the wire 23 is effected by a sleeve 24, split at its front end to grip the wire frictionally and pulled forwards by a spring 51 and lever 47 engaging between collars 49,50 on the shaft. The wire is held by interchangeable spring jaws 32 on the end of a drawing in spindle 26, which has no longitudinal movement. the jaws being closed by the coned end of the main spindle, which is pushed forward by springs 38 inserted between collars 36, 39 on the two spindles. The wire is released by a slight backward movement of the main spindle, produced by a yoke 46, operated by a rock-shaft 29, arm 54, and cam disc 56, the position of the cam being angularly adjustable on its disc to determine the time of opening. When freed, the wire is fed forwards against a disc stop 81 by the sleeve 24, and is then gripped, the sleeve being drawn back by a cam 52 acting on the lever 47. The amount of feed is adjusted by varying the amount of lost motion between the lever 47, and the collars 49, 50. A hand-lever 75 is provided to open the jaws when the spindle is at rest. The stop disc 81, Figs. 1 and 8<a>, is carried by a screwed projection 85 on a block 83, sliding on a rocking- arm 80, pivoted at 78 below the main spindle. The disc can be adjusted on the projection 85 to suit different lengths of screws, and the block 83 may be moved to or from the screw to allow the disc to engage the point or the shoulder of the screw when determining the feed. The turning- tool 82 is segmental, and is mounted on a block 90 adjustable across the arm 80 to suit different lengths of screws and is fed inwards by raising the arm 80. The arm is raised by a cam 100, operating a lever 96, pivoted at 97, and engaging a stud 77 on a slide 94, adjustable on the arm 80 to vary its angular movement for wire or screws of different diameters. A lug 99 on a spring 88 on the lever 96 may be forced downwards by a screw 89 to compensate for wear between it and the cam, with which it is held in contact by a spring 101. The cam 100 has three sections, the lungest being a gradual rise to effect the cutting- feed, the second concentric to hold the stop disc and tool clear of the wire as shown to allow it to be screwed, and the third a drop to allow the disc to be moved into the path of the wire while the feed takes place. The screwing-die 110 is secured to a plunger 111 sliding in the tailstock and normally withdrawn by a spring 113. The plunger is moved forwards by a lever 114 and cam 117, and is prevented from rotating, while screwing, by a pin 120 on it engaging a slide 121. When the pin reaches the end of the slide 121, the plunger and die rotate with the work, ceasing to cut. The main spindle is then reversed and the plunger held against rotation by a spring pawl 125, so that the die is screwed off, the lever 114 having been returned by a spring 116. The lost motion between the lever 114 and the plunger may be varied by a screw 118 to regulate the movement of the plunger for screws of various lengths, and the length of thread cut may be regulated by adjusting the slide. After the die is disengaged, the spindle is brought to rest, and the wire fed forwards, so that the next screw may be turned. Just before the tool 82 severs the screwed blank, a transfer chuck 135, Fig. 18, carried by an arm 133 on a rock-shaft 132, Fig. 1, is brought into engagement with the blank. The chuck is split to form spring jaws, and is pulled into a coned holder 134 on the arm 133 by a leaf spring 27. A coiled spring 150 on the rockshaft serves to bring the chuck opposite to the screw when allowed to by a cam, and to press the rock-shaft against a face cam 153, which allows the shaft and chuck to move forwards and screw on to the screwed blank B, Fig. 18, twisting it off. The cams then move the chuck and screw opposite a circular saw to cut the nick. The chuck is then pressed forwards by a lever 145 and cam 148, releasing the finished screw, which is ejected by a spring plunger 140, the spring of which is compressed by the insertion of the blank B. During the nicking operation the holder 134 is steadied by engagement with a standard 161, against which it is tightened by a slight rise on the face cam 153. The saw 175 is carried by a spindle in the forked end of a bell-crank lever 172, pivoted on a slide 166, Fig. 14, adjustable parallel to the main spindle by a screw 168 to suit various lengths of heads or depths of nicks. The lever 172 is held against end movement on the pivot pin 173, but this pin can be axially adjusted and locked to bring the saw directly opposite the screw. The saw is driven by a pulley 177 and band from a countershaft. The lever 172 is rocked by a cam 180 to cut the nick and returned by a spring. A stop-motion is provided to stop the machine when the wire stock becomes too short to be fed. When this takes place, the lever 47, Fig. 5, is pulled forwards an excessive amount by the spring 51, and operates a lever 186, releasing a lever 190 which trips a weighted lever and operates the fork of the main driving-belt.