US 4,209,272 AGranted

Apparatus and method of forming holes in plate glass

OwnerMasaaki Miyanagainventor

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Abstract

This disclosure relates to apparatus and method of forming circular holes in plate glass. A circular cut is made in the glass to a predetermined depth, which is less than the thickness of the glass by approximately 0.5 to 1.0 mm. After this cut has been made, the cutting apparatus is removed and the glass is softly struck adjacent to the circular cut in order to break loose the glass disc enclosed by the cut. The edge or margin of the hole may then be smoothed by grinding or polishing. The glass cutting apparatus includes a circular saw or glass cutter which is rotated to cut the glass. A stopper of the apparatus is adjustably mounted adjacent the cutting edge of the saw and stops the saw from cutting further after a predetermined depth has been reached. The position of the stopper may be adjusted for different thicknesses of glass.

Claims1

Dependent claims

A method of sawing a hole in plate glass using glass cutting apparatus including a circular core drill and stopper means mounted radially within said core drill, said drill having cutting teeth on a forward cutting edge and at least one axial slot formed therein, and the stopper means being movable axially of said drill, said method comprising the steps of:

positioning said apparatus with the drill and the stopper means against one side of said plate glass, viewing from a distance of more than approximately 30 cm. and from an angle of approximately 45.degree. from said axis the reflection of said stopper means from the other side of said glass and noting on said one side the location where said reflection passes through said one side;
moving said stopper means axially away from said one side until the reflection of said stopper means from said one side coincides with said location;
noting the distance between said cutting edge and said stopper means and calculating the thickness of said plate glass;
moving said stopper means toward said one side to make said distance less than said thickness by approximately 0.05 to 1.0 mm;
and cutting into said glass until said stopper means engages said one side.

2 more elements

Dependencies are inferred from the claim text.