From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Description and diagram of gear testers, specifically the helix angle tester and the involute form tester.
| Identifier | ExFiles\Box 174\2\ img068 | |
| Date | 27th March 1937 guessed | |
| -4- (4) Gear Testers. The helix angle tester (photo 9) is self-explanatory. The master rack is pushed in until it jambs in the teeth and the helix angle read from the dial on the sine bar while the depth to which the master rack tooth enters is read on the second dial indicator. The involute form tester (of which unfortunately I have no photo) consists of a knife edge wide rack tooth which contacts with one side of the gear tooth and is moved horizontally with a straight edge on which rolls a wheel whose diameter equals the gear base circle. This wheel is mounted coaxially with the gear being tested and deviations from the involute are read on a dial. [DIAGRAM TEXT] WHEEL WHICH MOVES INWARD & APPLIES PRESSURE BASE CIRCLE WHEEL STRAIGHT EDGE GEAR KNIFE EDGE RACK ARM ROTATABLE ON PIN PIN FIXED TO STRAIGHT EDGE DIAL INDICATOR MOUNTED ON STRAIGHT EDGE I understand the manufacture of this machine gave considerable trouble in the early stages. It now has very fine work put into it. The straight moves on roller slides. The pitch error testing machine - see leaflet - I did not see. | ||