| 摘要 |
<p>1421331 Polishing gem stones SPECTRUM DIAMONDS (PTY) Ltd 20 March 1973 [23 March 1972] 13719/72 Heading B3D Apparatus for polishing, shaping, grinding or cutting gem stones, such as natural or artificial rubies, emeralds, semi-precious stones, diamonds, handglasses and the like, comprises a polishing head for supporting a gem stone for pol ishing on a surface, the head being mountedon support means rigidly attached to a piston of a dashpot-assembly, lifting means for raising the piston together with the support means- and polishing head, and a liquid flow control system for the dashpot including means for providing liquid flow to the dashpot as the piston is lifted by activation of the lifting means and means for regulating liquid flow from the dashpot for controlled lowering of the polishing head when the lifting means is de-activated to bring the gem stone into contact with the polishing surface. The apparatus described is identical with that described in Specification 1,421,332:</p> |
