Patent GB-134240-A (GB)
Title: Improvements in Apparatus for Cutting or Polishing Gems.
Inventor: IMRAY OLIVER
IPC: B24B9/16
Filed: 1918-04-11
Abstract: 134,240. Imray, O., (Ries, F.). April 11, 1918. Gems, treating.-Relates to apparatus for cuting or polishing diamonds and other precious stones, of the kind in which the gem is held by adjustable fingers in a dop carried by a universally adjustable part mounted on a vertically slidable carriage, and comprises a carriage D slidable vertically in guides 6, 7 on the frame C and having thereon a boss 11, in which is carried an angularly adjustable socket E carrying an angularly adjustable arm F extending over the lap and carrying at its end an adjustable member G in which is mounted the adjustable gem-holding device H. The downward movement nf the carriage D is limited by the engagement of a graduated nut, carried by a screwed stem 35 on the carriage, with the frame, and the carriage may be lifted for inspection of the gem by means of a, lever 22 the inner end of which engages a roller 26 on the carriage, the weight of the carriage being counterbalanced during lifting by a weight 19 adjustably mounted on a lever 18 adapted to be turned on its pivot 16 either to add to the weight of the carriage or to counterbalance this; when turned to counterbalance the carriage, as shown in Fig. 1, the lever 18 engages a forked lever 15, lifting this to engage the boss 11. The lever 22 is then depressed by a thumb-piece 28 and lifts the carriage, a spring pawl 29 engaging a pin 33 on the frame to hold it in the raised position. In order to allow the descent of the carriage to be followed as the gem is ground, an indicator 39 is provided pivoted to the frame at 40 and engaged at its inner end by a pin on the carriage, the outer end 43 of the indicator moving over a scale 44. The socket E carrying the arm F may be turned in the split boss 11 and clamped in position by a screw 14, its adjustment being indicated by a pointer 45 and a scale 46, and the angular setting of the arm, about its axis, in the socket is determined by the engagement of a member 51, carried by the arm, with a stop-pin 52 adjustable on the socket by means of a screw 54 and a scale 55; the arm is clamped in position by a screw 48. At the outer end of the arm, a squared part 56 is provided, having therein an aperture for the stem of a member G, which may be set in any of eight angular positions about the axis of the stem by means of numerals on the top face of the squared part of the arm and locked in position by a nut 59. The lower end of the member G is bifurcated to receive a holder H pivoted on a pin 61 and having an extension 63 with a tapered socket therein adapted to receive the end of a collet I adjustable about its axis in the aperture to positions determined bv the engagement of an indexpin 70 with holes 69 in a flange 68 on the collet. The gem K is carried by a dop J seated in the collet and is maintained in position by means of prongs L, Fig. 12, fitted in sockets 74 in the collet and held therein by screws 75, the lower ends of the prongs engaging the gem so that the portion being cut is exposed; to expose fresh portions, the position of the prongs is changed. In a modification, Fig. 6, a prong M bears against the face of the gem, and the prongs L are replaced by a universal prong N, which may comprise two pivoted fingers 80 clamped on to the gem by a screw 83, or may comprise tongs having fingers actuated by a screw and having pins at their ends remote from the gem slidable in slots.