Irregular Forms of Patterns.
Year: 1898

page_text: Irregular Forms of Patterns.
I, ARTHUR GEORGE HOPPER, of Albion Works, Armley Road, Leeds, in the
County of York, Engineer, do hereby declare the nature of this invention to be
as follows:-
This invention relates to the preparing of moulds for casting toothed wheels
and articles having similar irregular forms, the object being to prevent the
breaking away of the sand, as the pattern is being withdrawn, or, in other words,
to ensure (say) the teeth of a wheel pattern lifting cleanly, without the necessity
for using water, as hitherto, which makes the sand very damp, and so causes the
teeth to be brittle.
In carrying out this invention, I employ plaster of Paris blocks in the ordinary
manner, and I fit loosely in a recess thereof, a flat ring, having, as it were,
internal teeth of a size equal to the spaces between the teeth of the wheel to be
cast.
This ring, which may be of any convenient thickness, is formed by casting
onto the pattern, in suitable white metal, which does not contract, and it is intended
to serve as a stripping-plate, to prevent the sand breaking away as the pattern is
being withdrawn.
Upon the plaster block fitted with this ring, I lay the pattern, with its teeth
registering with the spaces in the ring, and the sand is then rammed into the
box in the usual way.
The mould is then turned over, and the plaster block is removed, leaving the
ring behind on the sand.
The ring is then suitably clamped down, and the pattern is withdrawn, which
can be done by any ordinary labourer, without fear of breaking the teeth of the
mould, if ordinary care be taken.
The ring is then removed and the sand mould is ready for use.

page_text: Improvements relating to the Moulding of Toothed Wheel and other
Irregular Forms of Patterns.
I, ARTHUR GEORGE HOPPER, of Albion Works, Armley Road, Leeds, in the
County of York, Engineer, do hereby declare the nature of this invention and in
what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement:-
This invention relates to the preparing of moulds for casting toothed wheels
and articles having similar irregular forms, the object being to prevent the
breaking away of the sand, as the pattern is being withdrawn, or, in other words,
to ensure (say) the teeth of a wheel pattern lifting cleanly without the necessity
for using water, as hitherto, which makes the sand very damp, and so causes the
teeth to be brittle.
In carrying out this invention, I employ plaster of Paris blocks in the ordinary
manner, and I fit loosely in a recess thereof, a flat ring, having, as it were,
internal teeth of a size equal to the spaces between the teeth of the wheel to be
cast.
This ring, which may be of any convenient thickness, is formed by casting
onto the pattern, in suitable white metal, which does not contract, and it is intended
to serve as a stripping plate, to prevent the sand breaking away as the pattern is
being withdrawn.
Upon the plaster block fitted with this ring, I lay the pattern, with its teeth
registering with the spaces in the ring, and the sand is then rammed into the
box in the usual way.
The mould is then turned over, and the plaster block is removed, leaving the
ring behind on the sand.
The ring may be suitably clamped down, or held in position, while the pattern
is withdrawn, which can be done by any ordinary labourer, without fear of
breaking the teeth of the mould, if ordinary care be taken.
The ring is then removed, and the sand mould is ready for use.
In the accompanying drawing,
Fig. 1 is a cross section of a mould complete ;
Fig. 2 is a similar view of the sand box; and
Fig. 3 is a plan view of the ring.
A is the plaster of Paris block, contained in its box, which is provided with
registering pegs in the usual way. In the face of the block A is formed an
annular recess, in which the ring B is placed, so that its face comes flush with
the face of the block A. This ring is cast onto the pattern, and has internal
teeth, as before explained (see Fig. 3). C is the pattern, which is laid on the
block A so that its teeth register with the spaces in the teeth of the ring. Dis
the sand-box, which is then placed in position, and is filled with sand, which
is rammed round the pattern. When properly rammed, the mould is turned
upside down and the block A is removed, leaving the ring B on the top of the
sand, and the pattern in it (see Fig. 2). The pattern is now withdrawn from the
sand, the ring preventing the breaking away of the teeth, and the ring is then
removed for future use.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what 4
I claim is:―
1. The mode of preparing moulds for casting toothed wheels and other

page_text: irregular forms, as herein shewn and described, and consisting in casting onto
the pattern, in a soft metal which will not contract on cooling, a ring or plate:
fitting this ring or plate into the plaster block, on which the sand is rammed,
and afterwards, when the block is removed, using the said ring as a stripping
plate, as and for the purpose set forth.
2. In preparing moulds for casting toothed wheels and other irregular forms,
the use, as a stripping plate, of a ring or plate of a soft metal which will not
contract on cooling, and having a contour corresponding to that of the article
to be produced, as herein shown and described.
Dated this 25th day of March 1900
NEWTON & SON,
Agents for the Applicant.