GB940608A - Scribing instrument - Google Patents

Abstract

940,608. Engraving. S. E. PAVELEK. May 1, 1961, No. 15720/61. Heading B6J. [Also in Division B4] A scribing instrument comprises a ring-like body, means for supporting said body a predetermined distance above a working surface with its axis perpendicular thereto, a tube supported concentrically in the body so as to be freely rotatable as the body is moved over the working surface by an operator, and a tool having a working point and supported on means rotatable with and rigidly fastened to the tube so as to be disposed eccentrically of the axis of the body. A ring 20, Fig. 2, is supported on a working surface by three legs 14 each comprising a ball 15 spring-urged downwardly, so that downward pressure by the operator is necessary during the engraving operation. A carrier 16 is threaded into the ring so as to be vertically adjustable for depth of cut by rotation. The carrier embodies an annular recess receiving a bearing structure 23 having a stationary part clamped in the recess by a plate 25 and an inner part 27 rotatable about the axis 39 on balls 28, said inner part supporting a tube 29. A work head member 35 is supported frictionally, or positively by screws 37, on the tube 29. A cutting blade 40 is supported in a block 44 mounted in one of recesses 47, 48 in the member 35 at different distances from the axis 39 so as to position the working point 41 at one of two selected distances from the axis. Alternatively, the blade can be cemented into a transparent plastic disc supported on the work head. A magnifying lens 54 is removably supported by a structure 55 on the carrier 16. In another form, Fig. 5, the tube 76 is threaded internally to receive the work head 77, and the work head has ribs 78 and a groove 79 to receive a needle carrier block 80. The block 80 is mounted on the head 77 by means of an arcuate groove 82, Fig. 6, and a screw 84 which can be tightened to prevent rotation of the block about the axis. The needle 85 is radially adjustable by a screw 98. The carrier 73 can be locked into position in the ring 70 by means of a slot 86 through a segment of the carrier to remove part of one of the threads and provide separated thread portions 87, 88. An aperture 89 through the separated portions is threaded only in the portion 88. A stud 90 is inserted in the aperture 89 and turned to engage its threads with those of the aperture. The stud 90 is bored to receive a lens and mounting 92. The tube and head can be mechanically rotated by a shaft 93, a friction wheel 95 attached to which rests on a flange 75 of the tube when a stem 96 is inserted in a socket 97 on the carrier 73. The work head can be locked within the ring by a slidable plate 102 having arms 104 for releasably engaging the sides of the block 80.