Patent GB-712897-A (GB)
IPC: G01B7/28
Abstract: 712,897. Surface and outline gauges. TANDLER, W. S. Oct. 2, 1950 (Sept 30, 1949], No. 23987/50. Class 106 (2) An apparatus for gauging the dimensions and contours of a workpiece or for gauging the successive positions assumed by a moveable machine part, comprises means for taking the probe device repeatedly into temporary contact with the workpiece, means for effecting a relative displacement between the probe device and the workpiece intermediate successive contacts electrically operated means for marking a record strip at each contact of the probe device with the workpiece, and means for effecting relative movement between the recording device and the record strip in accordance with relative displacements between the probe device and the workpiece. The workpiece 14 is held in a rotatable support 12. A carriage 20 slides to and from the workpiece 14 and secured to the carriage 20 is a block 21 on which a carriage 23 is slidably mounted for movement in a direction at right angles to that of the carriage 20. The carriage 23 has an arm 24 carrying a slide 25 adjustably supporting a probe carrier 26 having a pair of probes 28 and 29 mounted on resilient arms at its base. These probes are moved into engagement with one side or the other of the workpiece 14 during the gauging operation and, intermediate of the probes 28 and 29 are a pair of safety feelers 30 and 31 spaced from the probes 28 and 29. The feelers 30 and 31, by electrical means, stop further movement of the arm 24 when either of the probes 28 or 29 is bent too far upon engagement with the workpiece 14. The carriage 23 is moved by a motor 32 driving also a drum 36 having a plurality of marks 37 corresponding to the position at which measurements are to be made on the workpiece for a fixed vertical position of the probe carrier 26. The marks 37 may be holes drilled in the drum 36 and they are scanned by a photo-electric scanner 38 mounted on an arm secured to the carriage 20. A knob 125 enables the drum 36 to be rotated manua'ly. The carriage 20 is driven by a motor 42 which also drives a record drum 43 having electrically sensitive paper 43<SP>1</SP> for recording gauging measurements. A stylus 44, for the recording drum 43, is secured to a carriage 45 engaging a lead screw 46 in a frame 47. The lead screw 46 is driven by an electrically operated ratchet mechanism 48 to move the stylus 44 laterally one step each time the probe contacts the workpiece at a fresh point. A knob 126 enables the record drum 43 to be rotated manually. The drums 36 and 43, and the rotatable support 12 all have calibrated markings 49, 51 and 53 co-operating with fixed pointers 50, 52 and 54 respectively. Automatic operation. - On pushing the start button 56, the motor 32 rotates moving the drum 36 past the scanner 38 and the probe 28 past the test piece 14. When the first mark 37 on the drum 36 passes in front of the scanning mechanism 38, the motor 32 stops and the motor 42 starts, rotating the drum 43 and bringing the probe 28 into engagement with the test piece 14. At the instant of contact, a mark is made on the paper on the drum 43. The ratchet mechanism 48 then advances the stylus 44 one step and the motor 42 reverses its direction of travel for a time determined by a timer T so as to bring the probe 28 clear of the test piece 14, and return the drum 43 to its original position. The motor 42 then stops and the motor 32 again starts to advance the probe 28 to another position as controlled by the scanner 38 whereupon another measurement is made as described above. This process is repeated until the entire contour is measured on one side. The probe assembly is then brought around to the other side of the test piece 14 by manual control of the motors 42 and 32 and the probe selector switch 109 is thrown over to its other position corresponding to the reverse direction of measurement and the process outlined above is repeated for the opposite side of the test piece 14. Measurements are taken at different elevations by adjusting the height of the probe-holder 26. In Fig. 3 are shown upper, middle and lower elevations along a test piece 14 respectively. The lower set of marks 99 correspond to the offsets obtained on the side of the test piece 14 nearest the apparatus while the marks 111 correspond to the offsets for the side away from the apparatus. Manual operation.-The knobs 126 and 125 are manually rotated to bring the probes 28 and 29 into engagement with the test piece 14 at a number of different points. Each time a probe engages the work piece 14 a mark is made on the paper 43<SP>1</SP> and the stylus 44 is then manually stepped to an adjacent portion of the strip 43'. Alternatively a light goes on each time a probe engages the work piece 14 and the readings on the dials 49 and 51 are then noted. Semi-automatic operation.-The lead 63 is broken and the stop button 56 is connected between the leads 66 and 80 to energize the relay P1 instead of the relay SP. The drum 36 is then adjusted manually to bring the probe 28 to a desired position. The start button 56 is then pressed to automatically bring the probe 28 into and out or engagement with the test piece 14 thereby causing the stylus 44 to make a mark on the record strips 43'. Another gauging position is then chosen by manually adjusting the drum 36. Determining deviation between test piece and specification-This may be accomplished bv prenaring in advance a record strip having marks 114 and 115 thereon, Fig. 4, which represent accurately the desired contours for the opposite sides of the test part 14. resnectively. Such a record strip may be prepared by mounting it on the record drum 43, moving the stylus successively to the several gauging stations, moving the drum 43 at each station until the scale 51 at the position of the indexing member 52 corresponds exactly to the known offset for that station, and supplying electrical energy to the stylus 44 may be promake a mark on the record strip at that position. To this end, the stylus 44 may be provided with an auxiliary energizing circuit (not shown) adapted to be closed by a push button. The record strip may also be prepared by running the machine automatically with a master part having the correct form in place of the test part 14. The part to be tested is then inserted in the apparatus and the actual offsets are recorded on the previously prepared record strip as represented by the marks 99 and 111 in Fig. 3. The marks 99 and 111 then represent the actual contours of the opposite sides of the test part 14, while the vertical distances between those marks and the corresponding marks 114 and 115, respectively, give the deviations between the two. Modifications.-The Specification describes modifications of the above apparatus whereby (a) a rotating cam, (b) the movement of a member such as tappet and (c) gear teeth may be gauged.