GB522412A - Improvements in gear hobbing machines - Google Patents

Abstract

522,412. Gear-cutting. GARNER, J. R. Dec. 1, 1938, No. 34956. [Class 83 (iii)] A gear hobbing machine comprises a hollow frame 1 having vertical slideways 5 which extend substantially the full depth of the frame and carry a vertical slide 4 fitted at the top with a cross slide 6 carrying the hob head 7 and provided with gearing for transmitting the drive from gearing mounted in the main frame to the hob spindle. The central recess 2, Fig. 4, in the rectangular frame has on either side hollow pillars 3 one of which houses a balance weight 8 for the vertical slide while the other serves as a housing for electrical equipment operating in the manner described in Specification 522,413. The compartment 30 of the frame houses the driving mechanism and is formed with a sloping roof portion 11 which carries the upper bearing 10 of the work spindle 9. The closed base 31 of the frame has an upstanding part 14 carrying the bottom spindle bearing 15. The hobbing head 7 on the cross slide overhangs the roof 11 which prevents cuttings from reaching the gearing and diverts them to an opening 16a leading to a cuttings chamber 16 from which the coolant flows through a passage 16b into a well whence it is recirculated. Lubricating oil is pumped from a well 1a to a distributing chamber from which pipes lead to the various parts to be lubricated. The work spindle is hollow so that-swarf may also pass through the spindle into the housing 14. The change gears are accessibly housed in a compartment 18 closed by a plate 18a. The vertical slide is operated by a screw 19 driven by bevel gears from a feedshaft 21, Fig. 11. The hob spindle is normally driven from themotor 27 through shaft 42, change speed gearing 44, shafts 43, 24 bevel gears 38, splined vertical shaft 23, bevel gears 22, shaft 34, and other gearing. The shaft 24 is also connected through change gears 46 to the work spindle 9. Further change gears 47 connect the work spindle to the feed shaft 21. When cutting helical gears, the rotation of the work is. modified through the differential gearing 45 which is driven from the feed shaft 21 through gearing 48 and change gearing 49. In order to obtain a quick return feed an electrically operated plunger controls two clutches 39, 41. The clutch 39 connects a belt drive 40 directly from the motor to the feed shaft, and disconnects the shaft 42. The clutch 41 disconnects the feed shaft from the work spindle. The in-and-out feed of the cross slide are operated from a separate motor on the cross slide controlled in the manner described in Specification 522,413. At the end of the slow downfeed the cross slide is withdrawn and the main motor stopped, reversed and the fast feed clutches energised to return the slide upwards. The machine may be used for either climb or down hobbing.