GB464916A - Improved method of and apparatus for machining and/or threading pipe sockets and the like, particularly boring tube sockets - Google Patents

Abstract

464,916. Machining pipe sockets &c. WEISER, R. F. Aug. 23, 1935, No. 23707. [Classes 83 (ii) and 83 (iii)] In making pipe sockets or the like, all the preliminary machining operations, prior to threading, are performed on one end of the blank by means of a single tool assembly, the blank being then turned end for end without re-chucking and the preliminary operations performed on the opposite end of the blank with the same tool assembly. The machine comprises two rotatable face plates 6, 7, carrying chucks, 8, 9 and a column 10 fitted with a cross rail 11 on which three tool heads 12 ... 14 are independently movable. The heads 12, 14, each carry the tools for preliminary machining operations on a socket S, Fig. 1, consisting of facing the ends to length at 1 boring the double-taper bore, recessing at 3, chamfering the thread start and chamfering the outside at 4. The head 13 is for cutting a continuous double-taper thread 2. The tool heads are traversed along the rail 11 by hydraulic cylinders 15 .. 17. A blank secured in the chuck 8 is first machined at one end by bringing the head 12 over the chuck axis. The head 12 is then moved to the left and the head 13 brought into alignment with the chuck to perform the screwing operation on one end during which the operator chucks a blank in chuck 9 and machines the same by bringing up the head 14. This head is then withdrawn to the right and the screwing head brought up to thread one end of the second blank during which the blank in chuck 8 is reversed end for end and the head 12 brought up to machine the other end of said blank, the operations being then repeated in the above sequence. The cylinders 15, 17 move with the machining heads and have fixed differential pistons 18, 19, Fig. 3. Fluid is supplied from a pump through a line 24 to manual valves 26, 27 directing fluid to opposite ends of the cylinders. In the position shown in Fig. 3 pressure fluid is admitted to the left end of cylinder 15 to move said cylinder to the left. Near the end of the movement the reduced piston portion 18b enters a chamber 18c at the cylinder end from which mild escapes to the exhaust line through an adjustable valve 38 to cushion the end of the movement. By shifting valve 26 fluid is admitted to the opposite cylinder end to move the head to the right, the end of the movement being cushioned as before by the piston portion 18a entering chamber 18d. The speed of this terminal slow movement is adjusted by a needle valve and serves to effect the facing of the socket to length. The movement is limited, to determine the exact adjustment of the machining head according to the work diameter by a boss 300 abutting screws 45. The boss 300 carries a valve 43 which is operated against a spring to admit fluid to a bore 48 to initiate the vertical movement of the machining head. The tapping head 13 is traversed laterally by a similar cylinder 16, its terminal positions over the chucks 8, 9 being determined by stop screws 52. Each machining head comprises a shank 55, Fig. 6, inclined according to the taper to be bored and carrying a plate 62 and a reduced extension 57 provided with a tool 58 which faces the socket to length during the traversing movement and forms the taper bore during the axial movement. A second tool 59 mounted in the shank at right angles to the first, recesses and chamfers the socket end while a tool 60 mounted on the plate 62 performs the external chamfering. The shank is secured to a slide 56 movable in adjustable inclined guides 64, 65 set to the required taper. The part 56 is formed as a cylinder with a stationary piston 67 with a differential end portion 73. Pressure fluid, constantly delivered above the piston by a bore 72, serves to maintain the head in raised position except when the valve 43 is opened on completion of the end facing operation. When this occurs fluid is admitted to a valve 78, Fig. 10, having a hollow plunger 79 enclosing a rod 86 secured to the slide 56. A pivoted handle operates the plunger 79. When fluid is admitted to valve 78 it passes to the lower side of the piston through passage 71 and the slide 56 descends until the spring 87 and other resilient devices in the handle cause the plunger 79 to move downwardly and shut off the line 71, whereupon the slide 56 moves upward to a stop shoulder 76. The valve plunger is returned by the handle. In a modification the valve 78 may be fully automatic. The face plates 6, 7 are driven from a motor 109 through a gear box 110 having shafts 111, 112 connected to the two face plates. For machining operations the face plates are driven through a friction clutch 119 and spur gears 120. For tapping, the drive is through gears 115, 118 and single tooth coupling 122. A gear 125 drives a vertical shaft 126 connected to the tapping-head through a coupling 148. The tap head includes a vertical slide 129 carrying a nut 130 engaged by a screw 131 driven from a vertical shaft 134 connected to the shaft 126 by gearing 140, 144, Fig. 15. The screw may be driven from the shaft 134 either forwardly for the tapping operation by gears 135, 138 or reversely at the higher speed to withdraw the tool by gears 132, 133a, selection being made by a clutch 133. The tool 149 is preferably of the receding chaser collapsable type. The clutch 133 may be automatically operated by a striker bar 152 carrying abutments 151, 153. An auxiliary spring-urged nut 155 eliminates backlash between the screw and the nut 130. Chucks.-The reversible chuck for holding the workpieces comprises a body 158, Fig. 17, carrying a frame 159 which is rotatable in the body on horizontal hollow trunnions 161 carrying nuts to receive screws operating the chuck jaws. The frame is secured against rotation by wedge blocks 164 operated by bolts 165 which may be rotated by a circular rack 166 on a hand wheel 168. The socket S rests on an extension of the wedges 164, Fig. 17. The socket is thus machined and tapped on the top half and the chuck is reversed to perform similar operations on the other half. In order to obtain continuity of the tapped thread, the tap is first set by hand so that any selected tooth of the tool is an exact number of pitches from the chuck centre. The coupling 148 is then connected. The operation .sequence is described in detail in the Specification.