Cabbing device for gemstones
OwnerClarence Poolinventor
Life of this patent
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Abstract
A machine device for generating a convex surface, especially for the formation of the front surface of a cabochon, inherently symmetrical without irregularities and in a range of sizes both spheroid and ovoid, and comprising a manually operable dop-stick to which workpieces are replaceably attached to be shaped about two selectively distinct radii, by advanceably offering the workpieces into grinding engagement with an abrasive wheel.
Claims16
A device for generating the convex surface of a cabochon selectively about two right angularly related axes, by offering the same up to a grinding surface, and including;
- a horizontally disposed base centered on a vertical plane before said grinding surface,
- a standard with means adjustably positioning the same with respect to said grinding surface, and comprised of a platform disposed over the base and a substantially vertical pivot standing upward therefrom to move in said plane toward the grinding surface,
- a hub free to be revolvably manipulated about the first mentioned pivot and having a horizontal series of transversely disposed pivot openings extending from the first mentioned pivot,
- and an elongated dop-head arm free to be revolvably manipulated about the second mentioned pivot openings and having a multiplicity of transverse pivot openings in a series extending longitudinally thereof to be individually and selectively aligned with one of said series of pivot openings on the hub,
- the dop-head arm being coupled a selective position by a replaceable pivot pin, whereby a workpiece carried by a head at the forward extremity thereof swivels about two distinct selected axes of rotation into engagement with the grinding surface to form a compound curvature thereon.
A replaceable dop-head adapter for alternative positioning upon the controlled end of a manually operable dop-stick in a machine generating a compound convex surface on a rough stone secured to a controlled dop-head arm and offered into engagement with a grinding surface, and including;
- a forwardly adjustable standard having a substantially vertical pivot standing upward therefrom to move in a plane toward the grinding surface,
- a hub free to be revolvably manipulated about the first mentioned pivot and having a horizontal transversely disposed pivot spaced forward of the said first mentioned pivot, whereby the dop-stick and dop-head arm is controlled to swivel about two distinct axes,
- a slotted sleeve member of cylinder form projecting forwardly from the dop-stick and dop-head arm respectively,
- an adapter plate having a front face to receive said rough stone to be grounded about distinct axes and disposed normal to the dop-stick and dop-head arm respectively,
- and a keyed member projecting from the back side of the plate and slideably engaged with said slotted member for rotative positioning of said dop-head adapter thereon,
- whereby the dop-head adapter is alternatively replaceable upon the controlled ends of said dop-stick and dop-head arm to move the said rough stone about said two distinct axes.
Dependencies are inferred from the claim text.