Patent GB-625009-A (GB)
Title: Improvements in gear finishing machine
IPC: B23F19/00
Filed: 1945-07-30
Abstract: 625,009. Gauging-apparatus. NATIONAL BROACH & MACHINE CO. July 30, 1945, No. 19510. Convention date, Aug. 16, 1944. [Class 106 (ii)] [Also in Group XXII] In a machine for finishing large gear-wheels by use of an intermeshing generator cutter rotating on a crossed axis with the work and reciprocated axially thereto, means are provided for setting the work axis parallel to the line of reciprocation and for testing the helix angle and pitch diameter of the work. The machine comprises a bed 10 carrying bearings (not shown) for the spindle of the work 17 which are horizontally and vertically adjustable relatively to the guides A for the reciprocating carriage 13 carrying the cutter 12. The work is rotatable by means of a headstock 11. For setting the work axis parallel to the guides A, a slide 24 of polygonal cross-section is mounted in bearings 26 on the carriage 13 and may be advanced to project over the work spindle B, Fig. 4, by means of hand wheels 32 and gearing 28 enga,ging a rack 27 on the slide. A member 35 is vertically adjustable on the end of the slide and carries a dial indicator 37 with an actuating plunger 37a so that for vertical adjustment of the work the gauge 37 is made to read zero when the plunger 37a contacts the highest point of the work spindle at one end thereof, and the member 35 is then locked by bolts 36. A saddle 40 is next adjusted by a rack and pinion, hand operated at 49, along guides 41 on slide 24 until a dial indicator 42 on the saddle reads zero when its plunger 42a is in engagement with an anvil 43a on a bracket 43 fixed to the carriage 13. The slide 24 is then withdrawn by hand wheels 32, the carriage 13 is traversed to the other end of the work spindle, and the slide advanced again until the gauge 42 meets the anvil 43a again with zero reading. The reading of gauge 37 'then indicates the vertical alignment of the work axis. For horizontal alignment of the work, the member 35 is lowered until a pointer 38c on a bell-crank lever 38 thereon is level with the work axis and the gauge 37 is raised so that arm 38a of lever 38 may engage its plunger 37a. Corresponding horizontal readings may then be taken with the slide 24 projected at opposite ends of the work spindle. The means for measuring the helix angle and pitch diameter of the work comprise two housings 50, Figs. 1 and 10, located on each side of the carriage 13 and movable transversely on the carriage by a screw 52 and gearing 56, hand operated at 55. The forward end of each housing carries a member 57 transversely adjustable to a small extent on ball-bearing guides 58 by means of a rack and pinion 60, 61, hand operated at 63, the member 57 having a plate 64 angularly movable with a central pivot 66 mounted by a ball-bearing 67 on member 57. Backlash between plate 64 and member 57 is taken up by balls and hardened plates 64b and the angular movement of plate 64 is limited by a pin 79 in the member passing through slots in the plates 64b. A bar 65 is attached to plate 64 and carries two adjustable slides 68, Fig. 9, each provided with a conical pin 71 shaped to engage the work on the pitch surface when inserted between two teeth. In use, the pins 71 are adjusted to be equally distant from the pivot 66 and spaced apart a distance which is approximately two-thirds of the length of face on the work and is an exact multiple of the linear pitch of the teeth parallel to the work axis, this adjustment being made by gauge blocks placed between cylindrical surfaces 71a and 66a on the pins and pivot respectively. The bar 65 is next set horizontally by placing a gauge block on an anvil projecting from the member 57, resting a pin 73 attached to the bar on the gauge block and engaging the plunger of a dial indicator 72 mounted on the member 57 on the top of the pin 73 with the indicator reading zero. The housing 50 is then projected towards the work and the member 57 adjusted laterally until the pins 71 make full contact with the flanks of the teeth, the indicator 72 then showing whether the bar 65 has been displaced from its horizontal position due to error of helix angle on the work, the axial pitch of the teeth being known to be correct. To correct such error, the angular setting of the cutter 12 on the carriage 13 is adjusted accordingly. To test the pitch diameter of the work, a dial indicator 74 on the carriage 13 is spaced from a finger 75 on the housing 50 by means of gauge blocks 76 and a micrometer 78 by an amount exactly equal to the pitch radius of the work, the indicator reading zero. With the gauges removed, the housing is advanced to the work, and if the pins 71 engage the work before the finger 75 restores the indicator to zero, the work is oversize and requires further cutting.