the mechanism of the formation of peaks

摘要

956,024. Lathes. NATIONAL MACHINERY CO. Nov. 22, 1961 [Feb. 8, 1961], No. 41824/61. Headings B3B and B3T. A lathe 11 for turning points on the shank ends of bolts &c. 36 comprises a rotating cutterhead 31, a reciprocating work-carriage 22, first gripping means 42, 46, operated by movement of the carriage, for gripping the head 43 of a blank 36 to locate it axially, and second gripping 42, 49, also operated by carriage movement, for gripping the shank 44 of the blank and locating it laterally. As shown, the lathe is mounted on a machine 10 for making bolts from wire-stock, the blanks being sheared from the stock, headed between dies, pointed in the lathe, and provided with screwthreads by a thread-roller 14. The cutter-head 31 has one or more cutters 33, 34 and a tapered shank engaging a spindle 29 which is rotated from an electromotor 138, by a toothed belt. Prestressed bearings support the spindle, and a disc 133 protects the bearings from coolant and swarf. The carriage 22 is guided in a frame 21 by rolls 24, the right-hand ones of which are carried by eccentrics 26 adjustable by screws 27 to take up play. The bolt-head is clamped against a lip 42 on the carriage by a rod 46 pressed upwardly by a spring 48. Acting on the rod 46 is a plunger 50 pressed by a spring 57 against an adjustable abutment 61 on a lever 58 pivoted at 59 to the frame 21 and having a cam surface 63 engaging a roller assembly 79. This bears against a pad 78 on the carriage and is carried by a rod 67 having secured by screws to its upper end a stop-collar 69 normally forced by a spring 77 against a sleeve 73 fixed in the frame 21, the compression of the spring being adjustable by a nut 74 on the collar 69. Thus the roller assembly is held resiliently as the carriage is moved down, causing the lever 58 to turn about the pivot 59 and operate the clamping rod 46. At the clamping pressure predetermined by the setting of nut 74, the roller assembly 79 begins to move down with the carriage. A similar spring-supported rod 89 carries a roller assembly 86 for operating the shank-clamping jaw 49. This is supported on a vertical pivot, Fig. 3 (not shown), and biased against the opposing jaw 42, by a spring 94 which allows a turned blank to be ejected by engagement with a succeeding blank. Clamping pressure of the jaw 49 is increased by the rollassembly 86 which operates the jaw through a lever 81 as the carriage is lowered. Adjustment of the stop-collars 69 on the rods 67, 89 decides whether the head or shank of the bolt shall be clamped first or whether they shall be clamped simultaneously. Carriage, feed.-This is effected, against the influence of a spring (not shown) acting on a rod 126 connected to the carriage, by a cam 19 connected to the drive for the heading dies. A follower 98 engaging the cam is carried by a lever 18, 99 which is on a pivot 97 and is connected by a rod 121 to a lever 122 engaging a roller 124 on the carriage. A toggle linkage 18, between the two arms of the lever 18, 99 and set by a spring 111, collapses upon excessive resistance to movement of the carriage, permitting the arm 18 to rotate relatively to the arm 99. The toggle-linkage may be self-setting if a stop-screw 127 prevents too much release movement of the linkage. Blanks transferring.-Blanks are delivered from a feed-tube 12 to a slide 146, Fig. 6, from which they are pushed between the jaws 42, 53 by a bar 144, which is connected to a lever 143 operated, by links and levers, from a cam 141. A gating element 148 operated by the bar 144 is retracted when the bar is advanced. The turned blank ejected from the jaws 42, 53 by the succeeding blank passes into the feed system 13 of the thread roller.