Patent GB-695725-A (GB)
Title: Improvements in devices for gauging hole centre distances
IPC: G01B7/12
Filed: 1950-08-09
Abstract: 695,725. Electric control systems. TANDLER, W. S., and TANDLER, G. B., [trading as INDUSTRIAL SCIENTIFIC CO.]. Aug. 9. 1950 [Aug. 9, 1949], No. 19849/50. Class 40 (i) [Also in Group XIX] An apparatus for indicating whether a hole is correctly positioned in a part subjected to a gauging operation comprises a probe extending into the hole, means producing transverse motion between the probe and the wall of the hole, means responsive to engagement of the probe device with the wall of the hole, and means for indicating whether or not the probe device engages with the wall of the hole between pre-determined positions of the probe. The apparatus includes relays and motors for automatically causing. the probe to perform a gauging operation in one direction, to reverse and then to perform a gauging operation in a second direction transverse to the first direction, the gauging operations being checked by a circuit including indicating lamps (see Group XIX), the sequence of operations being recorded on rotating drums in a manner providing a measure of the position of the holes. The means by which such recordings are made is described more fully below. Particular embodiment. The Figures show an apparatus for checking the position. of two holes 14 and 15 in a plate 13. The plate 13 is positioned by pins 17 Fig. 2 over an opening in a housing 10. Into each hole 14 and 15 extend probes 20' and 20 respectively, both probes being mounted on a carriage 25 slidable-on a guide 26 in a direction to and from a contact 74 Fig. 1. The guide 26 is itself part of a'carriage 41 slidable in a direction to and from a contact 72. By this means the probes 20 and 20<SP>1</SP> can be moved transversely of the holes 14 and 15 in mutually perpendicular directions. Mounted on the carriage 25 are'four additional probes 57, 58, 65 and 66. The additional probes 57 and 58 are adapted to contact rods 59 and 60 respectively of two micrometers 61 and 62 secured to the casing. Similarly the additional probes,65 and 66 are adapted to contact the rods 67 and 68 respectively of the two other micrometers 69 and 700. Setting up of apparatus. A plate 13 with the holes accurately positioned is placed on the pins 17. The carriage 25 is moved away from the contact 74 and the probe elements 20 and 20<SP>1</SP> are adjusted by screws 31 and 31<SP>1</SP> respectively till they just engage the portions of the walls of the holes 14 and 15 respectively which are remote from the contact 74. The micrometer barrels 61 and 62 are then adjusted until they just engage the probes 57 and 58 respectively. The micrometer barrel 61 is then backed off by an amount equal to the maximum tolerance specified for the hole centre distance and the micrometer barrel 62 is advanced a distance equal to the minimum tolerance specified. In a similar fashion, the probe elements 20 and 20<SP>1</SP> are adjusted by the adjusting screws 32 and 32<SP>1</SP> with the carriage 41 in a position towards the left of the housing 10 in figure 2 until they just engage the left-hand portions of the walls of the holes 14 and 15, respectively. Also, the micrometer barrels 69 and 70 are adjusted so that their spindles 67 and 68, respectively, just engage the probe elements 65 and 66. The micrometer barrel is then backed off an amount equal to the maximum tolerance specified for the hole centre distances, while the micrometer barrel 69 is advanced an amount equal to the minimum tolerance specified for the hole centre distances. Operation of apparatus. In operation, the submaster plate is removed and a plate 13 to be gauged is substituted therefor. The longitudinal carriage 25 is then moved forwardly (Fig. 2), to bring the several probe elements into engagement with the piece or with one of the micrometer spindles as the case may be. If the centres of the holes 14 and 15 are within the tolerances specified for the longitudinal direction of movement of the carriage 25, it will be understood that the probe element 58 will engage the spindle 60 before either of the probes .20 or 20' engages the walls of the holes 14 and 15 and that the probe element 57 will engage the micrometer spindle 59 after the probe elements 20 and 20' have engaged the walls of the holes 14 and 15. The longitudinal carriage 25 is then returned to its initial position and the transverse carriage 41 is moved towards the left to bring the probe elements into engagement with the piece 13 and with the micrometer spindles respectively. Here again, if the centre distances of the holes 14 and 15 for the transverse direction of movement of the carriage 41 are within the tolerances specified, the probe element 65 will engage the micrometer spindle 67 before either of the probe elements 20 or 20<SP>1</SP> engage the walls of the holes 14 and 15 in the plate 13, while the probe element 66 will engage the micrometer spindle 68 after the probe elements 20 and 20' have engaged the walls of the holes 14 and 15. By observing the order of engagement of the probe elements 20 and 20<SP>1</SP> with the walls of the holes 14 and 15 and of the probe elements 57, 58, 65 and 66 with their respective micrometer spindles 59, 60, 67 and 68, it may be noted whether or not the centre of the holes 14 and 15 lie inside or outside of the specified tolerances. The several probes are automatically moved in the manner described above by electrically controlled motors LM, TM and the engagement of any of the probe elements with the wall of a hole in the plate 13, or with a micrometer spindle, as the case may be, is caused to actuate indicating means. Recording. Record drums 36 and 47 are rotated with the screws advancing the carriage 25 and 41. When the carriage 41 is moving, a pulse is transmitted to a stylus 48 bearing on electrically sensitive paper on the drum 47 when the probe 20 engages the watch plate 13 and also when the probe 20' engages the watch plate 13. The distance between the starting point on the paper on the drum 47 and the point where a record is made by the stylus 37 is a measure of the distance from a reference location to the centre of the holes 14 and 15. When the carriage 25 is moving, similar marks are made by a stylus 38 bearing on electrically sensitive paper on the drum 36. After records have been made corresponding to one part, the styli 37 and 48 may be moved longitudinally of the drums 36 and 47 by manipulation of the hand-wheels 40 and 50, respectively, so that a further record may be made, and the several records may be identified by suitable markings on the electrically sensitive record strips. Reference has been directed by the Comptroller to Specification 662,073, [Group XIX].