from Plastic Compound, and Apparatus therefor.
Year: 1886

page_text: from Plastic Compound, and Apparatus therefor.
I, OLIVER IMRAY of N° 28 Southampton Buildings, Chancery Lane, in the
County of Middlesex, Fellow of the Institute of Patent Agents, 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 manufacture of clock-cases and other articles from
a plastic composition which is subjected to the pressure of a plunger in a mould
of suitable design according to the character and form of the article to be made.
The object of the invention is to provide an economical and convenient means of
producing, with but little time and labour, a mechanically pressed clock case or
like article formed in a single piece from a suitable plastic composition, susceptible
of a high finish.
For this purpose a special composition to be hereinafter described is moulded by
pressure in moulds of the required configuration, constructed as I will now proceed
to describe with reference to the accompanying drawings in which :-
Fig. 1 is a vertical transverse section of a mould for a clock case, with its
plunger and with the press frame and accompaniments shewn in dotted lines.
Fig. 2 is a perspective view of the plunger.
Fig. 3 is a perspective view of the mould partly separated with the face plate
turned down to expose its inner side and with its plug or disc portion detached.
Fig. 4 is a plan view of the mould.
Fig. 5 is a perspective view of a clock case or cast, made in accordance with this
invention.
A is what will be termed the "bottom plate" of the mould. This bottom plate
has its upper face formed to correspond with the lower face of a plunger B, and
between these surfaces is shaped the top or roof C of the clock case. It will be
observed that in the pattern shewn, the top of the clock case is partly arched, and
to produce this effect the upper face of the bottom plate A will be concaved and

page_text: the lower face of the plunger-B, will be convexed to correspond. It is obvious,
however, that in order to produce a different design the configuration of the bottom
plate and plunger will be varied accordingly.
At each end of the bottom plate A, is a flange a that is pierced for the passage
of bolts or screws by which the said plate is secured to the moveable. platen of a
hydraulic press. After the bottom plate A, has thus been secured in the press
the end plates D, D, are placed in position. These end plates are provided at their
lower ends with flanges, or lugs b, which rest on the flanges a of the bottom plate
and serve for the passage of screw holts c or other fastenings, by which said end
plates are secured to the body of the bottom plate. The end plates D, and bottom
plate A, may also be connected by means of dowels on one part entering mortices
in the other part.
The inner faces of the end plates D, D, as shewn are provided above and below
with transverse mouldings or bevilled depressions d and e which form corresponding
end projections d and e¹ at the base and upper portion of the clock case respectively.
These end pieces D D, are also provided on their inner front edges with vertical
offsets or projections ff of a rectangular or other suitable shape to form corre-
sponding vertical depressions or rebates f¹ f1 at the front corners or vertical edges
of the clock case. The upper portions of these end pieces are internally reduced
in thickness or set 'outward as shewn at g, to afford a sufficient space for accom
modating the enlarged base E of the clock case, while the surface between the
transverse mouldings or depressions d, e can be either plain, or have any suitable
relief according to the design selected. The exterior of each end plate D is
provided with a vertical strengthening rib, or ribs h, and with edge-flanges or
projections and k for the passage of screw bolts m, or other fastenings, that secure
the front plate F and back plate G in position.
In setting up the mould I prefer to first secure the bottom and end plates
together in the press as above described and then attach the back plate G, to the
said bottom and end plates by means of the screw bolts m, and with dowels on
one part entering corresponding mortices in the other part; or other suitable
fastenings may be employed. The front plate F, of the mould is secured in place
by means of its bolts m, and other fastenings if desired, in the same manner as the
back and end plates. By reference to Fig. 3 it will be seen that both the front
and back plates are provided with flanges that are pierced to correspond with
the similar flanges or projections k of the end plates and so afford a hold for the
fastening bolts. The back and front plates may also be provided with dowels or
tenons n to enter suitable mortices p in the bottom and end plates. It is obvious,
however, that instead of these bolts and tenons, or in addition thereto, other suitable
fastenings or clamps can be used. It will be seen, by referring to Fig. 1 that the
lower edges of the front plate F, and back plate G, rest directly on the platen of
the press, in such a manner as to cause the said plates to form a close and firm
joint with the adjacent edges of the bottom plate A, and end plates D, to which
they are securely connected.
The inner side of the front mould plate F, may be formed as shewn in Fig. 3
with transverse mouldings or bevilled surfaces d'and e* which occupy a position
at right angles to the corresponding surfaces d and e of the end pieces, when the
parts are connected and serve to form the front lower and upper mouldings d³, es
of the clock case, the said upper moulding being centrally curved to correspond
with the arched top of the case as shewn in Fig. 5. The inner face of the front
plate is also shaped at top and bottom, as shewn at g¹. Fig. 3, to afford space for
forming the front of the projecting clock base and its overhanging top, as shewn
in Fig. 1.
On the inner face of the front plate F near each end is a projecting pattern H,
of any desired form or outline for the purpose of moulding a similar recess K, in
the front of the clock case. These recesses K, K, and also the rebates f1 f¹ at the
front vertical corners of the clock case, are to be filled in with any appropriate
mosaic work or other desired ornamentation.

page_text: At or about the centre of the front plate F, and back plate G is a circular
internally threaded opening. L for receiving a cylindrical screw threaded plug M,
which projects a suitable distance into the mould. These plugs M M form circular
patterns to mould recesses that are afterward cut or broken through to make, the
circular openings N, N, in. the front and back of the clock case for introducing the
clock mechanism. Each pattern plug M, has at its outer end a flange m¹ that limits
the inward projection of said pattero, and it also has a central perforation closed
by a small screw plug m² the withdrawal of which, after completing the moulding
of the clock case, admits sufficient air to overcome any difficulty from suction in
subsequently removing the larger plugs M, and then detaching the mould and its
contained cast from the plunger.
The outer faces of the front plate F, and back plate G are provided with a series
of vertical strengthening ribs h² as shewn in Figs. 1 and 4. These ribs h¹ also
serve to afford a bearing for a jacket consisting of metallic plates to be placed
edgewise on the press platen at each side of the closed mould, the said jacket, as
shewn by dotted lines in Fig. 1, being held in place by angle plates that are bolted
to the press platen and provided with adjustable screw bolts for pressing the jacket
into close contact with the ribs on the exterior of the mould. By this means the
closed mould is so strengthened and braced as to obviate any liability of its being
weakened or spread apart under the pressure to which its contents are to be
subjected.
The plunger. B, is formed on its lower face to correspond with the form to be
given to the top of the clock case by the inner face of the bottom plate A, as before
mentioned. This plunger is preferably tapered as shewn in Figs. 1 and 2 for the
purpose of facilitating its disengagement from the moulded article without injury
thereto. If desired, the front vertical edges of the plunger may be fluted at f
to impart an inward swell to the clock case at the parts in rear of the corner
rebates above described. The upper part of the plunger B is bevilled in front
at g² to correspond with the swell or bevil on the inner front side of the base, E of
the clock case; and at each end of the plunger is an offset or transverse ledge a¹
for moulding a recess b¹ in the base of the clock case to receive the sounding
board, as shewn by dotted lines in Fig. 5. The upper end of the plunger B, is
formed with a horizontal laterally projecting rim P, having lugs, or flanges cl
perforated for the passage of screw bolts c by which said plunger is secured to the
fixed platen of the press, as shewn in Fig. 1. The plunger rim P, corresponds, in
general outline, with the interior of the upper end of the mould so as to be
received within the same for the purpose of pressing the lower edges of the inverted
clock case; and in the vertical edges of this plunger rim are formed vertical
grooves c³ to permit the escape of air and moisture during the operation of pressing
and moulding the clock case or like article.
It will be observed that the several parts of the mould are separable from each
other, and that the mould and plunger are so arranged as to form the clock case,
or like article in an inverted position. This arrangement enables the cast to be
formed and pressed with great facility and permits the ready disengagement of the
mould and plunger without injury to the cast.
Although I have described and illustrated a particular form of mould and
plunger it will be understood that I do not confine myself to the exact configuration
of parts as shewn, it being obvious that the design will be varied according to the
effect to be produced.
When a moulding apparatus of any particular pattern or design is first arranged
in the press it is preferable to place, the plunger in the mould after securing the
bottom, end and back pieces, and before closing the mould. The front plate, of the
mould will then be set in position and secured. The moveable or lower press
platen will now be elevated, as shewn in dotted outline in Fig. 1, until the flanged
rim of the plunger is brought in contact with the upper or fixed press platen to
which it can then be secured with the necessary accuracy of adjustment with
relation to the mould that is carried by the moving platen. The moveable press

page_text: platen and attached mould are then lowered leaving the plunger B, fixed to the
upper stationary platen, in a depending position, and ready to be received in the
mould when the latter is again raised. "
}
In the operation of making a clock case, or similar article, according to this
invention, the mould will be secured in position on the moveable platen of a
hydraulic or other, suitable power press; and a plastic composition.consisting of the
ingredients to be presently described, or their equivalents, will be placed in said
mould. This plastic composition' is arranged around the mould in contact with its
bottom and sides, in such a manner as to leave a central space for the entrance of
the plunger. The quantity of the composition to be placed in the mould will
depend of course on the size and thickness of the article to be made, and should be
sufficient to closely and uniformly fill the space between the plunger and mould so
that under the operation of pressing, a dense, firm and finely grained casting will
be produced. Before introducing the plastic coin position the interior of the mould
should be oiled and oil should also be applied to the plunger. On elevating the
lower press platen and attached mould the plunger will enter and press the plastic
composition against the bottom and sides of the mould so as to completely fill all
the space between said mould' and plunger, beneath the plunger rim P, while the
vertical grooves c³ in the said rim will afford a vent' for escape of air and moisture:
After say fifteen or twenty minutes engagement with the plunger, the composition
will have set sufficiently to permit the removal of the casting. If the mould has
been surrounded with' a strengthening jacket, as before described, this jacket will
now be reinoved. The small screw plugs m³ are then withdrawn to permit the
entrance of sufficient air to prevent suction in the removal of the circular pattern
plugs M, the withdrawal of which admits an increased quantity of air to overcome
suction in disengaging the mould and contained casting from the plunger.. After
withdrawing the plugs M, M, a small stick or suitable implement. can be introduced
through the openings L in the front and back plates to break away the thin
portion of the casting between said openings 'and the plunger. The moveable
press platen and attached" mould can now be lowered without exposing the cast to
injury. In order to remove the casting from the mould it is preferable to first
detach the back plate G, then the front plate F, and finally the end plates, D, D,
after which the moulded clock case or like article can be lifted from the bottom
plate A, and set aside.
I
After removing the article from the mould any surface imperfections, that may
occur, are to be filled with the same composition, and the surface is then smoothed
with a 'hone or by other suitable means. If desired the article can then be dipped
in a dye composed preferably of extract of logwood, five pounds, copperas, one
pound, and tincture of iron, half a pint, the whole being boiled in about twenty-
tive gallons of water until the ingredients are thoroughly dissolved and mixed.
This dye is preferably used hot and the clock case may be permitted to remain
therein about fifteen minutes, or long enough to colour. any light specks remaining
after the honing operation. After the article is taken out of the dye and dried it
is subjected to any well known polishing manipulation to impart a fine glossy
surface.
F
The composition of matter which. I prefer to employ for the purposes of this
invention consists of "Keene's cement". such, for instance, as is manufactured by
J. B. White & Bro, England, to which cement water, alum, rosin and glue is added
in about the proportions hereinafter stated. In making this composition there is
first formed a mixture of water, say two gallons, alum one pound, rosin one pound,
and glue one half pound. The alum, rosin and glue are first dissolved in the water
and when required for use it is preferred to add a suitable colouring matter, for
instance English or ivory drop black, in sufficient quantity to impart the desired
shade. One pound of the black to ten pounds of the cement is a suitable pro-
portion. With this mixture is thoroughly incorporated a sufficient quantity of
Keene's cement, saý ten pounds to make a mass having the consistency of tempered
potter's clay. Either Glauber's salts or Epsom salts, or sulphate of manganese, or

page_text: any two or all of these ingredients, may be used in the composition instead
of alum.
A composition clock case moulded under pressure in a single piece, and in an
inverted position, from the material described will have a firm hard and dense
texture of fine grain and capable of taking a high polish.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed, I declare that what
I claim is
1. The use for moulding clock cases and other articles, of a plastic compound
consisting of Keene's cement, alum, rosin, and glue, prepared substantially as
herein described.
2. The herein described method of making clock cases and similar articles from a
plastic compound capable of hardening whereby the compound while plastic is
moulded in an inverted position under pressure by means of a plunger and after
Betting is honed, dyed and has its surface finished, substantially as set forth.
3. In a mould for clock cases, the combination of a bottom plate shaped to
mould the top of the case, end plates detachably secured to the said bottom
plate, and front and back plates detachably secured to the bottom and end plates,
substantially as described.
4. In a mould for clock cases, the combination with the vertical front and back
plates having circular internally threaded openings, of circular screw threaded
pattern plugs adapted to close said openings, substantially as described.
5. Constructing the circular pattern plugs referred to in the preceding claim,
with a perforation closed by a plug and with a flange at the outer end thereof,
substantially as and for the purposes set forth.
6. In a mould for clock-cases, the combination of a bottom plate adapted to
mould the top of the case, detachable end plates shaped to mould the ends and
front vertical corners of said case, a detachable back plate, and a detachable front
plate shaped to mould the front of the case, said front and back plates being
provided with central openings closed by detachable and centrally perforated
pattern plugs, substantially as described.
7. In combination with apparatus for moulding clock cases composed of a bottom
plate to shape the top of the case, and detachable front, back and end plates,
with or without external ribs, the use of a plunger constructed and operating
substantially as described.
8. Constructing the plunger referred to in the preceding claim with vertical
flutings f, ledges or offsets a¹, and vent grooves c³, substantially as and for the
purposes set forth.
9. The use in combination with a mould for a clock case or similar object, of a
press whose table is provided with a supporting jacket for the sides of the mould,
while the plunger for the mould is attached to the platen of the press.
10. An improved manufacture of moulded clock cases or similar objects formed
of a single piece of plastic composition, by charging a mixture of cement, alum,
rosin and glue, while in a plastic condition into a mould in which it is subjected to
pressure by a plunger.
Dated thin gat dan of Anil 1000