Patent GB-763793-A (GB)
Title: Direct reading linear-dimension gauge apparatus
IPC: G01B5/20
Filed: 1955-01-21
Abstract: 763,793. Linear-dimension gauges. CREEK, J. O., and DAWSON, E. W. Jan. 21, 1955, No. 1905/55. Class 106 (2). A linear dimension gauge has a base 1 on which is supported a feeler 24 and a dial gauge 25, a carriage 2 mounted on the base for longi. tudinal sliding movement and carrying the work to be gauged, e.g. turbine blade B, a drum 4 mounted on the base 1 for rotation about an axis parallel to the direction of movement of the carriage 2 and having spaced longitudinal ridges 4a in its periphery and transverse recesses 4b in the ridges 4a, and a stop-pin 6 mounted in the carriage 2 adapted to enter any of the recesses to position the carriage in several predetermined longitudinal positions relative to the base 1, the longitudinal positions of the recesses in one ridge being different from those in another ridge. A hand knob 9 is secured by a shaft 5 to the drum 4, and has a series of holes 9a, Fig. 4, each of which registers with one of the ridges 4a. A hub having a handle 10 fits freely around the shaft 5 and is secured to a bearing-plate 8 so as to permit a limited rotary movement of the handle 10 about the shaft 5. A pin protruding from the surface of the hub engages one of the holes 9a in the knob 9. The knob 9 is spring-urged in a clockwise direction so that the stop-pin 6, Fig. 6, is pressed into the wedge-shaped recess 4b. To change the longitudinal position of the carriage 2 the handle 10 is depressed, producing a limited anti-clockwise rotation of the knob 9, freeing the stop 6. To engage the stop 6 with a recess 4b in a different ridge 4a the carriage 2 is moved forward so that the stop 6 emerges from one groove and disengages the drum. The knob 9 is pulled out to disengage the pin on the hub from one of the holes 9a, the knob 9 then being rotated and the pin engaged with the appropriate hole 9a, the carriage 2 is then moved back until the stop 6 registers with the required recess 4b when the handle 10 is released, engaging the stop in the recess. A table 15 is mounted for transverse sliding movement on the carriage 2 between stops 17 which can be secured to the table 15 by screws 19, the stops 17 carrying screws 20 adapted to bear against abutments 18 secured to the carriage 2. Chucks 23, 23a on brackets 21 carried by the table 15 support the workpiece, e.g. the blade B, between the anvil 24a and the feeler wheel 24 of a dial gauge 25. The apparatus can be adapted to make several measurements of thickness, e.g. at leading edge, central axis and trailing edge of the blade B, at each of two stations along its axial length, the measurement being repeatable for any number of similar workpieces at the same points in each case. The blade B, which has a locating boss adapted to engage a corresponding bore in the chuck 23 is placed in position in the chucks and the brackets 21 fixed in position on the table 15 by screws 22. The stops 17 are set relatively to the abutments 18 by appropriate gauge blocks so that readings are made on the blade at the two predetermined stations. At each station readings are made with the stop 6 engaged successively in three predetermined recesses 4b in the ridges 4a. The chucks 23, 23a may be mounted so as to permit rotation of the workpiece about its longitudinal axis. In further embodiments of the invention the chucks 23, 23a are adapted to rotate the blade about its longitudinal axis, and the blade mounting may remain stationary while the gauge mechanism moves relatively to it.