Patent GB-828800-A (GB)
Title: Improvements in or relating to measuring attachments for the co-ordinate tables of precision drilling machines
IPC: B23Q17/24
Filed: 1956-05-28
Abstract: 828,800. Drilling-machine details. M.S.O. MASCHINENUND SCHLEIFMITTELWERKE A.G. May 28, 1956 [May 28, 1955; Jan. 7, 1956], No. 16505/56. Class 83 (3). A measuring-attachment for the compound table of a co-ordinate drilling-machine comprises scales reading in opposite directions and pointers for the scales. The readings 2f, 2g may be disposed above and below graduations 2e, common to both scales, Fig. 4, or located between separate sets of graduations which may read in opposite directions from a common zero (Fig. 5, not shown). The scales may be graduated both in inches and centimetres; oppositely-directed scales and graduations may be of different colours. For fine adjustment, the scales are viewed through a microscope, or an enlarged image 7, 8, Fig. 6, of a corresponding scale is projected optically on to a ground glass screen 6, a scale 11 sub-dividing the main scale 7, 8 being introduced into the optical system and viewed through the microscope, or on the screen 6, on which it may be engraved. For still finer adjustments, the screen 6 and scale 11 may be displaced, relatively to the projected sub-divisions 7, 8, by turning a ring 13, the amount of this displacement being indicated by a scale 11a with oppositely-directed readings 9a, 10a. As applied to adjusting the compound table 23, 25 of the drilling-machine of Fig. 9, a coarse-adjustment scale 28 for the cross-slide 23 is mounted adjustably on a support 32 on the machine-bed 15, and a coarse scale 29 for the table 25 is adjustably-mounted on a support 33 on the table. The scales are viewed through lenses 34, 35, mounted on the cross-slide in supports 36, Fig. 10, and protected by glass 40. A diaphragm 41, Fig. 11, secured eccentrically to the bottom of the lens-holder 37 and perpendicular to a cross-wire 42, conceals the scalereadings not in use and can be re-positioned to expose these readings by rotating the holder. The operative scale is illuminated through a slot 51 in the holder by one of a pair of lamps 43, 44, behind light-filters 52, 53 of different colour. For producing the enlarged image 7, 8, Fig. 6, of two graduations similar to those on the coarse scales 28, 29, two further scales are provided, that (58) corresponding to scale 28 being supported adjustably on the bed 15, Fig. 14, and that (58a, not shown) corresponding to scale 29 being similarly mounted on the table. A carriage 59 for the scale 58 is pressed by a spring 67 against a micrometer-screw 64 in a nut 65 on the bed 15, and coupled by gears 63 to a motor 62 having separate windings for each direction of rotation. The carriage is brought automatically to the mid-position of its travel by operating a press-button 80, on a control panel, Fig. 16, in circuit with the motor 62, and with switches 76, 77, Fig. 15, operated by the ends of the carriage 59. Further switches 78, 79 limit the adjustment of the carriage 59. The screens 6, buttons 86, 87 controlling the lamps 43, 44, a lamp 81 illuminated when the scales 58, 58a are in their mid-positions, and buttons 82-85 controlling operation of the motors 62 (62a) for adjusting the scales 58, 58a away from their mid-positions, are located on the control panel. Instead of a rotating lens mounting with an eccentric diaphragm, the scale may be rotated to expose the readings in the desired direction and change the colour of the light illuminating the scale. Operation.-For setting the table 25 so that a hole may be drilled in a workpiece at a distance of, say, 180.128 mm. from a datum hole in the work, press-button 80 is operated to brirg the scales 58, 58a to the mid-positions. The mounting for the lens 35 for scale 29 is then adjusted to illuminate the scale reading in the required direction, and the scale is adjusted to zero beneath the cross-wire 56, as shown in Fig. 13. Scale 11a, Fig. 6, is then set to zero before scale 58a, corresponding to scale 29, is adjusted from its mid-position to bring its projected graduations 7, 8 between the doubleline zero graduations of scale 11, the latter adjustment being effected under control of the press-button 84, 85 by a motor 62a (Fig. 17, not shown) similar to motor 62. Scale 11a is then set to displace the scale 11 by 28/1000 mm. by rotating the ring 13, readings 9a or 10a of scale 11a being followed, which are the same colour as the light-filter illuminating the coarse scale 29. Adjustment of the table follows until the crosswire 56 beneath lens 35 coincides with the dimension 180 mm. on scale 29. Further adjustment of the table is then made until the graduation 7 or 8 of scale 58a is located between the double-line graduation 0.1 mm. on scale 11, readings 9 or 10 of scale 11, which may be in staggered relationship, being followed, which are the same colour as the operative light filter.