Patent GB-301371-A (GB)
Title: A machine for pointing and threading screw blanks or the like
IPC: B23G7/00
Filed: 1928-02-06
Abstract: 301,371. Landis Machine Co., (Assignees of Mathias, S. W.). Nov. 28, 1927, [Convention date.]. Lathes; screwing .-Machines for turning and threading articles such as bolts and screws and similar castings or forgings comprise a blank supplying hopper C, pointing, rounding, chamfering or ending up mechanism. E, threading- mechanism G, and work turret D. The machine is driven by a single pulley 2, if desired from a self-contained motor L. A pulley 17 on the shaft 2 drives a coolant pump K. The pulley 2 is connected to a sleeve, keyed on the shaft 3, by a taper plunger 18 so controlled by an adjustably loaded spring as to yield in the event of overload. Drive is transmitted through change gearing 4, 5 and oevel gears 7 to a gear 11 meshing with wide face gears 13, 15 on the threading and turning spindles respectively. Hand drive is provided for at 21. The principal parts of the machine have separate frames or casings which are bolted to the main frame A. Cam shaft drive.-The main cam shaft 58, Fig. 10. is yieldingly driven through a: worm wheel 56<2> connected to the shaft by taper-ended spring-controlled plungers and driven by a worm 56<1> at a constant high speed, for turret indexing and idle movements of the slides, through a clutch gear 60 driven by a pinion 59 on the shaft 3, or at a speed correlated to the speed of the die-head, for feeding, by a clutch gear 26 driven through change gears from a pinion 23 keyed to the gear 5. The clutch 57 is controlled by a pivoted yoke 62, Fig. 17, operated with lost motion by a lever 64 linked to a bell crank 65 carrying a roller 65<3> for engagement by a dog on the cam shaft and a roller 65<2> engaging a V-ended spring plunger 67, which imparts a load-and-fire action. The roller 65<3> is engaged by a fixed dog 68<1> on a wheel carried by the shaft 58 and located to come into action at the end of the indexing movement. A second, reversely acting, dog 68<2> is adjusted in a slot 68<3> to come into action at the end of the threading operation. The lost motion is controlled by screws 71 on the lever 64 engaging pins 72 on the yoke. Pins 69 also on the yoke engage adjustably fixed abut ments 70 to limit the throw of the clutch. The auxiliary cam shaft is driven at the same speed as. the main cam shaft 58 by a gear 100 acting through an idler. Threading-mechanism. - A self-opening-die head is carried by a spindle 14, Fig. 10, mounted in adjustable taper roller bearings in a slide 28 moving in gibbed ways on the frame, a taper gib with end adjusting screws being provided to adjust for wear. The ways of the slide 28 extend almost, to the front of the die-head and carry an adjustable screw 39 set to engage the face of the turret when the desired length has been threaded and so cause the die-head to open. On the return stroke an abutment on the frame engages a lever carried by a rock shaft 40<1> and causes a yoke 40 to reset the head. The cam feeding-means and spring starting-mechanism described in Specification 313,002 are employed. Turning is effected by a hollow cutter head comprising a formed tool 50 with a lateral clamping and an end adjusting screw and carried by a spindle 16 mounted in roller bearings on a slide similarly to the threading spindle. Feed is effected by a cam groove 38<1> and roller 55<1>. Turrets; work-holders.-These are described in Specification 313,004. Blanks, transferring.-Blanks are supplied from a hopper C to a shoot 107, Figs. 22 and 27, by sector blades 106 passing through a slot in the hopper and spaced apart according to the diameter of bolt shank so that the blanks hang in the shoot by their heads. The blades 106 are carried by an arm 105 on a rock shaft actuated by a second arm linked through universal joints to a crank 85<1>, Fig. 2. on the upper end of the auxiliary cam shaft. On the wall 107<2>, Fig. 41, of the shoot an escapement mechanism may be mounted which only permits the blanks to aklvance singly to the end stop M. The mechanism comprises guides for plungers 132, 133 relatively adjustable according to the diameter of the blanks. The plungers are yieldingly actuated through springs by pins 138 passing through slots in the plungers and engaging the ends of the springs. The pins are actuated by links 137 adjustably pivoted to a double arm 136 on a rock shaft to vary the throw of the plungers according to the diameter of the blanks. The rock shaft is actuated in the direction to insert the stop plunger 132 between two blanks by a spring and in the direction to insert the release plunger 133 by a cam on the arm 105. The means for transferring the blanks from the shoot to the work-holders are described in Specification 313,003. When the levers ope': to release the finished bolt, as described in the above-mentioned Specification, a spring acts, under the control of a cam, to eject the bolt if it does not at once fall away. The ejector is pivotally mounted to yield in the event of obstruction during milling. The cam positively retracts the ejector, before the fingers present a new blank, by means of a two-armed lever. The bolts fall on to a trough 160, Fig. 47, with a perforated bottom which allows coolant to drain to a trough 176 for return to the machine. The trough is supported by a swinging arm 162 and by a suspension 164 from a bell crank 166 oscillated by a connecting rod 173 through springs 174, which permit yielding when a lug 160<1> on the trough strikes an abutment screw 175. The shock thus imparted causes the bolts to travel towards the discharge end of the trough. The connecting rod is actuated by a lever 170 with stroke adjustment at 172 from a cam groove 168 in the side of the constantly running gear 60. In a modification the screw 175 is dispensed with and a cam having a steep drop is employed. If the trough is not employed the bolts fall into a bin J. Cuttings are collected in a bin I.