Improvements in or relating to the measurement of errors in, for example, gears in transmission systems

摘要

910,939. Electric measuring systems. SYKES Ltd., W. E. Dec. 12, 1958 [July 7, 1958], No. 40226/58. Class 40 (1). A method of measuring errors in angular velocity ratio of a transmission system involves the use of rotary carriers bearng recorded magnetic traces, the recording on one carrier being produced by playing back the recording on the other carrier with the use of the transmission system. Gears 1, 2, errors in which are to be measured, are fixed on shafts 3, 4. A drum 6 rotated by a motor 7 bears two identical magnetic traces which are picked up by a fixed head 8 and a head 5 moving with shaft 3 which is constantly rotated. The difference frequency from these heads is derived in a mixer 13 and fed to heads 9 and 12 which, at this stage, are fixed and which record two traces on a drum 10 driven, at this stage, by shaft 4. Heads 9, 12 are now disconnected from mixer 13 and connected to the input of a mixer 15; head 12 remains fixed, but head 9 is rotated by shaft 4 and drum 10 is rotated by a motor 11. Thus a second difference frequency is derived in mixer 15. The two difference frequencies are equal and are independent of the speed of rotation of the motors 7 and 11. The phase relationship between the two difference frequencies is determined in a meter 16 and variations therein which are indicative of errors, are recorded by apparatus 17. If meter 16 is arranged to respond only to variations which occur at a lower frequency than the rate of rotation of the drums, then errors due to lack of uniformity in the records will be avoided.