Patent GB-339852-A (GB)
Title: Improvements in or relating to gear cutting machines
IPC: B23F1/04
Filed: 1930-01-27
Abstract: 339,852. Gleason Works, (Assignses of Hill, M. H., and Carlsen, L. 0.). Sept. 21, 1929, [Convention date]. Gear - cutting. - A gear generating machine such as a bevel gear shaper having relative rolling movement between the blank and the tool mechanism, the blank indexing being effected from the rolling mechanism during withdrawal of the blank from the tools, has means whereby, for gashing out non-generated teeth, the rolling movement may be controlled so that it occurs only when the blank is withdrawn from the tools. The tool mechanism, which is mounted in a slide 22, includes a pair of tools acting on opposite tooth faces of the gear blank and reciprocated in opposite directions. The blank G is mounted in a cradle 25 which may be oscillated in guides in a standard 21. A plate 26 carried by the cradle is provided with concentric arcuate slots 27, 28 on which the workhead carrier 30 is angularly adjustable. The work head 31 is longitudinally adjustable on its carrier to set the blank to the required cone distance. The work-head carrier is guided for its angular adjustment by a tongue 145 engaging the slot 28 and the head is guided for the longitudinal adjustment by a tongue 146 engaging a groove 147 in the head. A single pair of bolts 149, 150 passing through elongated slots in the work-head serve to clamp the work-head after its longitudinal adjustments. For this purpose the bolt 150 may first be rotated to clamp the carrier 30 to the plate 26 between a T-shaped nut and a collar 154 and subsequently a nut 155 moving on a threaded part of the bolt 150 may be rotated to clamp the work-head to its carrier. In order to exclude dirt from the slots 148, guard plates 160 which are pivoted together at 161 and are notched at 162 to receive the clamping bolts are arranged to guard the slots 148 in all positions of adjustment of the head. The work head 31 has an extension 33 on which is journaled a sleeve 34 keyed to a member 35 which is clamped by bolts 38 to an arm 37 engaging an adjustable gear segment 39 which engages a crown gear segment 40 to control the rolling movement of the blank. The gear blank is secured by a draw-bolt 46 in a hollow work-spindle 42 journaled in the workhead. The work-spindle carries an index disc 52 and a ratchet wheel 50. A plate 54 on the sleeve 34 carries an adjustable plate 57 carrying a pivoted lever arm 59 in which is mounted a locking-dog 60 coacting with the notches in the disc 52 to connect the sleeve 34 and work-spindle 42 during cutting, so that the rolling movement is communicated to the work-spindle. A fixed pawl 65 coacting with the ratchet wheel is controlled by a cam surface 68 on the arm 59. The rolling movement continues until a pivoted trip dog 70 engages a lug 75 to rock the arm 59 about its pivot and withdraw the locking bolt. The cam surface 68 is then lifted from the pawl 65 which thereupon engages its ratchet wheel, thus locking the work-spindle against movement with the sleeve 34. During further rolling movement the locking-dog moves into the next notch in the index wheel thus indexing the blank and again locking the work-spindle and sleeve. The pawl 65 is at the same time withdrawn by the cam surface 68. The plate 57 and with it the arm 59 and the locking-dog may be angularly adjusted by a screw 81 in order to adjust the blank slightly with reference to the tools. During indexing the tools are withdrawn from the work. For this purpose a control shaft carries a tool feed-cam 91 and a cradle-oscillating cam 92. A slide 94 is connected by an adjustable pivot 96 to a lever 97 which is actuated by the cam 91 and is pivoted at its upper end to a block 93 on the tool slide 22, thus giving the required feed and withdrawal movements to the tool mechanism. A complete withdrawal of the tools for changing the blank may be effected by means of :t shaft 131 actuated by a lever 130 and connected to the slide 94. A lever arm 108 pivoted at 105 is actuated by the cradle cam 92 and is connected to an adjustable rod 109 which oscillates the cradle 25, For gashing operations the generating motion is preferably not used and in this case the cradlecperating cam has a concentric portion maintaining the cradle stationary during cutting and a raised portion serving to move the cradle to actuate the indexing mechanism after withdrawal of the tools. The cam shaft is driven from a motor (not shown) through feed change gears and worm gear. A removable gauge is provided to locate successive roughed blanks in the same position on the work-spindle. The gauge comprises a collar 170 having a pin located in a notch in the spindle and carrying an adjustable bracket 173 fitted with a plate 177 which is adjustable about the axis of a stud 178. The plate carries an adjustable bar 180 on which is pivoted a plate 183 carrying a pivoted finger 187 which is adapted to engage a tooth space in the blank. In use the blank is first set by engaging the tools correctly in a roughed out tooth space and the gauge is then adjusted until the finger 187 engages in a tooth space. The movable parts of the gauge are then locked in this position and subsequently succeeding fresh blanks may be located with the gauge finger engaging a roughed out tooth space and may then be clamped in the correct position relative to the tools.