GB408394A - Improvements in or relating to means for measuring or setting out angles - Google Patents

Abstract

408,394. Grinding. BLAY, G., and SWIFT, E. A., Upper Market Street, Woolwich, London. Dec. 7, 1932, No. 34671. [Class 60.] In apparatus for measuring or setting out angles, a screw carrying an indicator to be engaged with a part to be set, e.g. a rotary table, is axially movable by rotation of a nut and has fixed thereto an arm engaging a cam shaped to cause rotation and additional axial movement of the screw so that equal angles of movement of the nut correspond to equal angles subtended by the axial displacement of the screw at a fixed point, e.g. the centre of the rotary table. In a modification the nut may be axially movable and carry the indicator. In a form adapted to be attached at 76 to a surface grinding machine, the work during a grinding operation is placed against the accurately ground side face 78<1> of an arm 78 on a spindle 77 rotatably mounted in the supporting plate 75. A sector plate 79 fixed to the spindle 77 has a number of accurately spaced holes 80 to accommodate a removable setting pin 81, which is brought into contact with the contact arm 83 when setting the arm 78. The arm 83 supported on the screw 11 is adjustable by the nut 12, arm 34 and cam 38, so shaped that upon axial movement of the screw 11 due to rotation of the nut 12, a rotation and further axial movement of predetermined amount is given to the screw 11 and saddle 22. The cam may also be shaped to compensate for inaccuracies of the thread.