GB1169190A - Variable Spindle Speed Transmission System - Google Patents

Abstract

1,169,190. Boreing machines. FOSDICK MACHINE TOOL CO. 1 Dec., 1966, No. 53921/66. Heading B3C. [Also in Division F2] A variable-speed transmission for rotating the spindle 6 of a jig borer comprises an expanding pulley gearing followed by a planetary gearing which gives a low ratio or direct drive. The expanding pulley gearing comprises a driving pulley 30 driven by an electric motor 28 and having a fixed flange 66 and an axially movable flange 67 which is connected through a bearing to a sleeve 80 which is in screw-threaded connection with a shaft 87 which can be reversibly rotated by an electric motor 48 to adjust the pulley diameter. A driven pulley has a spring biased axially slidable flange 70, The output shaft 32 of the pulley gearing is connected by a toothed belt 50 to an input shaft 51 of the planetary gearing. The planetary gearing has input and output suns meshing stepped planets in a carrier 140 which can be clutched to the input shaft 51 by an electromagnetically controlled friction clutch 168 to give direct drive from the input shaft 51 to an output gear 53, and which can be stationed by an electromagnetically controlled brake 170 for low ratio drive. The output gear can be stationed by an electromagnetically controlled brake 171 to station the jig borer spindle. The brake 171 and the low ratio brake 170 can be momentarily engaged alternately to jog the spindle. The electric motor 48 of the pulley gearing and the clutch and brakes of the planetary gearing may be controlled by separate manual controls, alternatively the transmission may be regulated automatically under tape control. Indicating output speed.-A tachometer generator 37 is driven by the output shaft 32 of the pulley gearing and energizes a tachometer having two sets of calibrations corresponding to the direct drive and low ratio settings of the planetary gearing. Spindle feed.-The output gear 53 of the planetary gearing drives a spindle sleeve 52 which rotates the spindle at the desired speed by way of a splined spindle drive shaft 15. The spindle 6 is journalled within a non-rotatable quill 5 which is shiftable vertically with respect to the drill head 3 at a selected feed rate to advance the spindle with respect to the workpiece 10. The sleeve 52 is also connected, by a tooth belt 55, to the input shaft of a changespeed gear for the spindle feed transmission. Feed motion is thus transmitted to the spindle at a selected rate which is related to the selected spindle speed. Rapid advance and retract is provided by rapid traverse motor 45, energization of which disengages the clutches of the spindle feed change-speed gearing.