A machine for grinding or/and lapping port hole cover interior seatings and a methodof reconditioning a cover seating at a port hole having an internal cover

摘要

770,450. Grinding; lapping. DEWRANCE & CO.; Ltd. April 27, 1955 [April 30, 1954], No. 12582/54. Class 60 [Also in Group XXIV] A machine for grinding and lapping a planar seating 4 on the interior of a valve body 2 around a port 3 of greater length than width, this seating being engaged, when the valve is in use, by a port hole cover pressed thereagainst by the fluid pressure within the valve body. comprises a casting 10 having a base part 10a and an upstanding flange 10b. The base 10a has holes corresponding with studs 13 permanently fixed to the valve body 2; the base is clamped against shoulders on the studs by nuts 14. A dovetailed slide 18 is mounted in the flange 10b for movement in the direction of the length of the port 3. the travel of the slide being limited by adjustable stop screws 22 carried by the slide and engaging the ends of the flange 10b. A bracket 25 clamped to the slide 18 includes a sleeve 28 extending downwardly through an elongated aperture 11 in the base 10a and split down one side, stud bolts 31 extending through radial flanges 30 on each side of the split foradjusting the diameter of the bore of the sleeve. A hollow shaft 35 fits within the sleeve 28 so as to be rotatable and axially movable. A flange 47 on the shaft 35 is located between a shoulder on the lower end of a feed gear worm-wheel 44 and a ring 4.9 threaded on the end thereof; the worm-wheel 44 is internally threaded to mesh with external threads on a boss 38 of a. guide 39 secured to the bracket 25. Rotation of the. worm-wheel 44 thus effects axial movement of the shaft 35 without restraining 'its rotation. The worm-wheel 44 is rotated by a worm 110 mounted on a shaft 111 carrying a grip-wheel 112: Mounted on the bracket 25 to one side of the shaft 35 is a gear-box 80 through which extends an axially movable shaft 84 carrying at one end a crank handle 87 and at the other end a worm 88; the shaft carries bevel gears 90, 91 for engagement with a bevel gear 92 on a shaft 94 carrying a chain-wheel 95 connected by a chain to a chain-wheel 52 slidable on the hollow shaft 35 but coupled thereto by a key 53. The worm 88 engages a worm-wheel 101 on a shaft 102 having a screw-threaded end 102a engaging a nut member 104 fastened to the flange 10b. Rotation of the crank handle 87 thus causes traverse of the slide 18 relative to the base 10 in a direction parallel to the length of the port 3 and in a sense dependent upon the sense of rotation of the handle. Reaction between the worm 88 and worm-wheel 101 causes shaft 84 to move axially engaging one or other of the bevel gears 90, 91 with the bevel gear 92 so that the hollow shaft 35 is always rotated in the same sense despite reversal of the sense of rotation of the handle 87. The lower end of the hollow shaft 35 carries a support member 58 extending laterally of the axis of the shaft 35 and disposed within the valve body below the seating 4 to be operated upon. The support member 58 comprises an elongated main part 125 secured by screw threads to the lower. end of the shaft 35 and having a dovetailed groove 126 in which is fitted a slide 128. The slide 128 has secured thereto a housing 140, projecting through a slot 141 in the main part 125, in which is mounted by ball bearings a spindle 146 to the upper end of which is secured a cup grinding wheel 149 which is thus carried bodily around the axis of the shaft 35 as the shaft 35 rotates. The slide 128 is adjusted relative to the part 125, so as to adjust the eccentricity of the grinding wheel 149 relative to the axis of the shaft 35, by a spindle 133 carried by a bracket 131 of the part 125 and having a screwthreaded end engaging a screw-threaded hole in the slide 128, the spindle carrying at its outer end a grip-wheel 136 for rotating it. The slide 128 carries two flanged jockey pulleys 160 each rotating on a spindle 162 having a flange 163 and a squared part 162a fitting within slots 166, 167 in the slide 128 and part 125; the upper screw-threaded end 168 of each spindle carries a nut 169, provided with. a gripwheel surface 170, which acts through a washer 171 on the upper surface of part 125 to draw flange 163 of the spindle into tight contact with the lower surface of the slide 128, thus securing the jockey pulleys and the slide 128 in their adjusted positions. A driving belt 177 passes around a flanged pulley 154 keyed to the grinding-wheel spindle 146, around the jockey pulleys 160 and around a flanged pulley 74 secured on the lower end of a shaft 64 which extends through a slot 175 in the slide 128 and is journalled in the hollow shaft 35. The upper end of the shaft 64 carries a flanged pulley 69 driven through belt 119 by. an electric motor 115 clamped to a block 116 secured to the rear face of the slide 18; shims, between the motor and block serve to adjust the belt tension. The grinding wheel may be replaced by a lapping disc,