Patent GB-531759-A (GB)
Title: Improvements in or relating to horizontal boring, drilling, milling and like machines
IPC: B23B39/02
Filed: 1939-07-07
Abstract: 531,759. Variable-speed gearing. GIDDINGS & LEWIS MACHINE TOOL CO. July 7, 1939, No. 19835. Convention date, June 7. [Class 80 (ii)] [Also in Group XXII] A facing attachment particularly for use in a horizontal boring, drilling, and milling machine comprises a tool support which is rotatable with the axiallymovable tool-spindle of the machine and is formed with a transverse guide way along which a tool may be traversed by gearing including change-speed and reversing gearing mounted in the attachment during its rotation so that, in facing, the tool moves in a spiral path over the work. The machine has the usual tailstock support 12 and headstock support 14 arranged at opposite ends of the bar, and the table 11 is carried on a saddle 16 movable along the bed by a screw 18 driven from a motor 21 through gearing 20. Vertical screws for the simultaneous power adustment of the headstock and tailstock are also operated from the gearing 20. The headstock carries a main sleeve 30 rigid with a gear 31 driven from the motor 21 through a vertical shaft 39, gearing 36, change speed mechanism 34 and gears 32. A tool-spindle 40 is splined in the sleeve 30 and may carry a boring-tool socket 41. The spindle may be axially adjusted by hand or power by means of a rack 42 rotatably anchored to the spindle at 43 and actuated from a vertical shaft 47 through worm gearing 46 and pinion 44. Hand adjustment is effected from a wheel 48 and for power feed the shaft 47 is driven from the gearing 20. The facing attachment comprises a housing 51 secured to the sleeve 30 and carrying a transverse slide 53 which is slotted to pass the spindle 40. The slide may carry either a facing tool 56 or telescoping boring tool 59 or boring tool 59a. While the tool 56 is facing the work may be bored by a tool carried in the socket 41. The facing tool is fed radially at a speed having a selected relation to the rotational speed of the work. The radial feed is derived from a stationary gear 68 on which rolls a gear 67 connected through spiral gears 70, change-speed gearing 69, bevel gears 72, shaft 75, reversing clutch 76, shaft 77, reversing clutch 78, and gears 79 to a worm 81 engaging a rack on the slide. The reversing clutch 78 serves for manual reverse of the feed and has a neutral position for stopping the feed. In order to obtain a wide range of speeds with the use of small gears, the gear connections are additive and give speeds in geometric progression. The driving member consists of a double gear 87, 84, mounted on a stationary shaft 83, carrying similar loose double gears 85, 88, and 86, 89. The larger gears 87, 88, 89 mesh directly with gears 97, 99, 101 respectively of a set of six gears 97-102 mounted loosely on a shaft 91. An intermediate shaft 90 carries a loose gear 92 and two loose double gears 93, 95, and 94, 96. To select a gear a spring-pressed sliding key 103 on the driven shaft 74 is engaged with one of the gears 97-102 the movement being effected from a dial through pinion 109 and circular rack 110. When the key is engaged in the gear 97 a drive is obtained directly from driving gear 87 but if the key engages gear 102 the drive is transmitted through gears 84, 94, 96, 88, 85, 93, 95, 89, 86, 92, 102. At each step of the key from gear to gear a reversal of the drive occurs but to obtain a unidirectional movement of shaft 77 the setting dial is connected to a three lobed cam 111 which actuates a rod 112 to change over the reversing clutch 76. Reversal of the feed of the facing slide is obtained from the clutch 78 actuated by a lever 125. Manual feed is obtained by turning the shaft 126 by means of a hand crank.