IMPROVEMENTS IN APPARATUS FOR ENGRAVING OR CUTTING GLASS. AND [OR] OTHER HARD SUBSTANCES
Year: 1883

page_text: PROVISIONAL SPECIFICATION left by John Henry Johnson at the Office
of the Commissioners of Patents on the 31st July 1883. Communicated
to bim from Raphael Josia a person resident at Florence in the Kingdom of
Italy Engineer.
66
JOHN HENRY JOHNSON of 47 Lincolns Inn Fields, in the County of Middlesex,
Gentleman, IMPROVEMENTS IN APPARATUS FOR ENGRAVING OR CUTTING GLASS.
AND [OR] OTHER HARD SUBSTANCES," a communication to me from Raphael Josia,
a person resident at Florence in the Kingdom of Italy, Engineer.
This Invention relates to apparatus for engraving or cutting glass crystal or
other hard substances such as metals marble and the like and it consists in the
employment as hereinafter described of arms or pallets revolving in a case supplied
with hard granular material such as sand or emery which is projected by centrifugal
force against the surface that is to, be engraved or cut.
Those parts of the surface of the glass or other substance that are not intended
to be cut or engraved are covered with a protective covering or coating as
hereinafter described and the unprotected portions of the surface are then exposed
to the abrading action of the sand, emery, or other hard granular material.
The improved apparatus constructed according to this invention is provided
with a main driving shaft carrying a series of revolving arms or pallets enclosed
in a drum or case supplied through suitable valves with sand or emery from
chambers arranged at the sides of this drum.
The dust resulting from the action of the apparatus escapes through a wire
gauze screen into a discharge passage and the sand after acting on the glass or
other article falls upon inclined planes whereby it is directed back into the
lateral chambers. The main shaft is driven by a pulley on an intermediate shaft
which may be driven by hand or by means of a belt passed round a suitable
pulley fast on the said intermediate shaft. The articles to be cut or engraved
are placed over an opening in a table above the revolving pallets and the entire
machine is supported upon a frame of cast iron.
The design cut or otherwise formed in a sheet of varnished paper or india
rubber or other suitable material is placed over the opening in the table above
the pallets and the article to be cut or engraved is then placed over the said
D9.71

page_text: sheet or the drawing or design is drawn upon the surface of the article with
protecting ink which may be composed of gelatine, glycerine, honey, water, and
lamp black, mixed to a suitable consistency at about forty degrees centigrade or
the said design may be formed by means of photography with gelatine.
The shaft carrying the pallets is then set in motion and the valves between the
said chambers and the drum are gradually opened whereupon the sand being
whirled round by the arms or pallets is projected by centrifugal force against the
article, then falls down the inclined planes into the lateral chambers and is returned
to the drum to be used again. The dust resulting from the operation is carried
away by the draught of air produced by the pallets and after passing through the
wire gauze screen passes through a passage into a discharge pipe or passage to the
exterior of the building, or other suitable place of discharge.
The power of one man ordinarily suffices to produce the required effect upon the
-surface of the article in a few minutes the unprotected parts being worn or caten
away by the abrading action of the sand or emery so that the design or drawing is
faithfully reproduced even in its minutest details:
When operating on round surfaces the article is held as in a lathe 'between an
adjustable centre and a chuck on a rotating shaft. The article being enclosed in a
drum of wood or pasteboard the sand is confined and caused to fall back into the
chambers hereinbefore described.