GB854498A - Improvements in or relating to the gauging of cam profiles - Google Patents

Abstract

854,498. Gauging departure from standard form. BIRMINGHAM SMALL ARMS CO. Ltd. April 3, 1957 [Jan. 24, 1956], No. 2250/56. Class 106 (2). Apparatus for gauging the profiles of cams 60 formed integrally with a cam-shaft 1 by coupling the shaft 1 for rotation with a standard cam-shaft 2, the shafts rotating in unison, comprises gauging members 28, 29, adapted to contact and radially follow the respective cams 60, 61 to be compared, supported by an arm 20 bridging both shafts 1, 2 and engaging at one end with a plane surface 22 extending along the apparatus, the other end of the arm 20 being mounted to slide on and swing about a shaft 19 disposed parallel to the master camshaft 2, and including means 33 for detecting any departure between the profiles of the cams 60, 61 being compared. As shown, the shaft 1 is mounted in half-bearings 4, 5, 6, and the standard cam-shaft 2 is similarly mounted. The cams 60, 61 being compared are engaged by feelers 28, 29, mounted in guides 24, 25 on the arm 20, and the difference between their movements is indicated on a dial gauge 33. The shafts 1, 2 are geared together by means of an idler pinion, so that they are rotated at the same speed and in the same direction by means of a hand wheel 45, means 50, 52 being described to adjust the angular position of the shafts and indicate angular discrepancies between the cams. The half-bearings 9, 5, 6 are mounted on blocks 10, 11, 12, adjustable along slides in the base 3 to accommodate different sizes of camshaft. In operation, the feelers 28, 29 are placed on steeply rising portions of the cam-flanks, the dial gauge 33 is adjusted to zero by means of an adjustable anvil 34, and the angular position of the shaft 1 noted by means of a scale on the hand wheel 45 co-operating with an index mark on a fixed arm 59. The hand wheel is now turned until the feelers 28, 29 contact the cam peaks, and it is then turned further through the same angle, and the dial gauge 33 read again. The adjustment 50, 52 is then operated to reduce the reading of the gauge by half, the hand wheel turned back to its original position and the dial gauge re-set to zero. The cams 60, 61 are then in the same angular position. The above sequence is then repeated to check this setting. The profile error can then be read from the gauge 33 during one complete rotation of the hand wheel 45.