Patent GB-232615-A (GB)
Title: Improvements in screw machines
IPC: B23G1/10
Filed: 1925-04-16
Abstract: 232,615. Globig, A., and Malmedie & Co. Maschinenfabrik Akt.-Ges. April 17, 1924, [Convention date]. Void [Published under Sect. 91 of the Act]. Lathes; turning wood-screws. -In a machine for making bolts, studs or wood-screws the blanks are carried to a series of tools in a single turret provided with revolving chucks, the blanks being turned end for end at one stage of the sequence of operations. The turret c is keyed to a rotatable sleeve 32, Fig. 2, and is intermittently rotated and indexed by a spring-plunger 60 mounted on a slide 59, Fig. 1, reciprocated by a lever 57 and a cam on the shaft x, this shaft being driven at 31, Fig. 3, at a speed of one revolution per stage of the turret, and carrying all the cams which control the movements of the machine. In making screws having a head, the blanks are inserted at A, Fig. 1, in a chuck which is closed by a camoperated sliding rod 63 having a rigid arm 63<1>. At the station B a rod t having a turning-tool mounted in the lever-rest e is oscillated by a cam to shape the head, and at D a similar rest t<1> faces the head after it is has been nicked at the station C. When the blank reaches the station E, the chuck is opened and spring fingers on a lever y, seize the blank, withdraw it, and reverse it by means of a pinion 72 and a. camreciprocated rack 71, Fig. 3. An arm 11, carried by a rod 12 reciprocated by a cam 80, then pushes the blank head-first into the same or a succeeding chuck which is closed bv a camoperated rod 14. The thread of the screw is next cut by turning-tools 19, Figs. 1 and 2, mounted in blocks 20 radially adjustable by screws 28 on a quadrant-shaped rest 35 keyed to a shaft 34 coaxial with the turret and capable of rocking and sliding under the influence of cams and springs. Additional tools 21 may act on the ends of the screws at the beginning of the threading operation. The screwing feed is supplied by a lead-screw 37, Fig. 3, on a spindly belt-driven at 49 and engaging the end of the shaft 34, and a nut-segment 38 carried by a lever 39 oscillated by a cam 41. When the screw 37 has passed off the nut-segment the turret is indexed, the rest 35 is rotated by a cam 82 and lever 44 to allow the tools to clear the threads already cut, the nut-segment is withdrawn by the cam 41 and springs 54 return the tool-rest. In a modification of the blank reversing-mechanism, the spring fingers are rotatably mounted in a, lever oscillated in two perpendicular directions by cams, to pick up the blank, the fingers being rotated by a quick-pitch screw actuated by a solenoid to reverse the blank. The chucks are carried by spindles b, Fig. 2, having pinions 51 rotated by a central gear 50 chain-driven from the cam-shaft x at 53. In a modification, the spindles b have a bearing at each end and a pinion at the middle, the gear 50 then being accommodated in the turret which is hollow. Steady rests. - A spider g, Figs. 1 and 2, keyed to a sleeve 33 coaxial with the turret has a series of radial arms which support the work at each tool station. The spider normally revolves with the turret but when the blanks are being reversed in the chucks it is given a backward rotation to clear the heads of the screws by means of a cam 43 and an arm 85 in the sleeve. A spring g<1> keeps the arms pressed against the work. Copying mechanism.-In turning wood-screws, a conical form is given to the thread by means of the cam 82, Figs. 2 and 3, along which a roller 46 on the arm 44 passes and gives a rotary motion to the tool-rest 35 as it is being traversed. Milling-machines.-A milling-cutter h, Fig. 1, is mounted on a spindle i carried by a slide k reciprocated axially by a cam and spring to cut a slot in the bolt or screw-head. The spindle is driven by a belt v from the cam-shaft x. The blank is held stationary during nicking by spring- fingers o carried by an arm m on a shaft n oscillated by a cam, the chuck jaws being opened to release the blank by a cam-operated rod. Instead of a, single slot, flats for a spanner may be cut on the bolt-head. Chucks.-The chucks for rotating the blanks comprise lever-jaws 5, 5<1>, Fig. 2, shaped so as to grip either the head or shank of a, screw and closed by a bevelled sleeve 56 rotatable with the jaws and movable axially by cam-operated sliding rods. Springs 55 open the jaws when they are released by the sleeves.