FR93863E - Improvements to machines for lapping flat surfaces. - Google Patents

Abstract

1,250,646. Lapping. R. S. STOKUIS & FILS. 11 Dec., 1968 [12 Dec., 1967], No. 58907/68. Heading B3D. A lapping machine of the kind in which workpieces are held in annular holders above a lapping table and pressed on to a lapping disc, rotating in an aperture in the table, by weighted covers slidable within the holders, has cover lifting means suspended from an articulated arm pivoted on the shaft about which the disc rotates. The holders are located by means which are indexed to bring them to loading and unloading positions. A base (1) carries an annular table 2 surrounding a circular, flat, horizontally disposed bed 3 rotating at slow speed. Cylindrical rings 4 contain workpieces which are pressed against the bed by heavy metal covers 5. The rings are located by arms 8 carried by a central vertical shaft 10 connected with indexing means for permitting the shaft to rotate intermittently in the direction of rotation of the bed through an angle equal to half the angular spacing of the rings. An arm 70 freely pivoted by bearings 71 on the shaft 10 is pivotally connected by bearings 73 to a lever 74 of rectangular cross-section. An electric motor 75 secured to the lever 74 drives, through reduction gearing 76, a pinion 77 fixed to a cam 78 having a lobe 78a operating a reversing switch 19. To the pinion is fixed one end of a chain 80 which passes over an idler 81 and from which is suspended a hub 83, having a journal (83a) on which a thick disc 85 is rotatably mounted by bearings (84). The hub 83 is connected by links 88 to a support 87 fixed to the lever 74, thus restricting the disc 85 to vertical movement. The disc 85 is frustoconical to facilitate engagement in a crown 89 fixed to each cover 5, and has radial pins 86 engageable with bayonet slots 95 in the crown. The end of the lever 74 has a handle 90 and a button 91 for operating a switch 92 for starting the motor 75. An unloading table 57 is slightly below the bed and a loading table 58 is slightly above the bed; the edge of the table 58 adjacent the table 57 has a ramp (93) extending down to the level of the table 57. Operation.-When the operator considers that workpieces contained in one of the rings 4 are suitably lapped, he stops the machine with that ring opposite the table 57 and by manoeuvring the arm 70, 74 by the handle 90 he brings the disc 85 above the cover 5 of that ring. He then lowers the disc 85 and engages the pins 86 in the bayonet slots 95 in the crown 89. By moving the arm 70, 74 the ring 4 is brought on to the unloading table 57 and, by pressing the button 91, the cover 5 is raised. The cover may then be moved into position on workpieces contained in another ring 4 waiting on the loading table. The arms 8 are then displaced one step and the loaded ring fed on to the bed 3 by means of the arm 70, 74. The unloaded ring can be moved from table 57 to table 58 by means of the arm 70, 74. During lapping the table 58 is moved back into position 58a so as not to interfere with rings which project slightly beyond the bed.