Improvements in or relating to Compression-devices for Moulding- machines.
Year: 1896

page_text: Date of Application, 2nd May, 1896-Accepted, 8th Aug., 1896
COMPLETE SPECIFICATION.
Improvements in or relating to Compression-devices for Moulding-
machines.
I, CHRISTIAN HAMILTON GRAY of the Indiarubber, Gutta-percha and
Telegraph Works Company Limited of Silvertown in the County of Essex,
Indiarubber Manufacturer, 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 compression-devices for moulding-machines such for
example as are described in the Specification of Letters Patent No. 9353 of 1896
granted to me. In these machines a plunger constituting one end of a compressor
exerts pressure on a body of plastic material to impart a desired form to it by
compressing it into a mould constituted in part by the end of the plunger, the
mould cavity having a shape corresponding to that which the plastic material is
required to assume.
The object of the present invention is to prevent the plastic material from
spreading laterally between the meeting faces of the plunger and the companion
part of the mould during compression, and accordingly the plunger is provided
with a preferably yielding tubular extension or sleeve; the end of the sleeve is
normally in advance of the plunger and meets the opposed face of the mould
before compression begins, in order that the plastic material previously placed in
the mould may be completely enclosed during compression in a manner which
prevents undesired lateral spreading thereof.
The accompanying drawing illustrates a compressor according to this invention
partly in section and partly in elevation, together with a mould just below it and
containing a "blank" of plastic material in readiness to receive the impact of the
plunger.
In
A is the body of the compressor secured to the apparatus by which the
compressor is caused to reciprocate in the direction of its length. A¹ is a screw-
threaded socket in which the screw-threaded rod A 2 is adjustable to vary the
effective length of the compressor as desired. B is a lock-nut to secure the rod A2
after adjustment. To the lower end of the rod A 2 is secured a plunger A 3 and
in the lower end A. 4 of the plunger or a die carried by it and readily removable
therefrom is a coucave or other matrix shaped to impart the desired form imprint
or pattern to that part of the plastic "blank" D with which it comes in contact.
E is a sleeve encircling the plunger, projecting in advance of the same, and having
its end E' shaped to fit close against the opposed face of the mould F below it.
the present example the sleeve is provided at its upper end with a flange E 2 and
the rod A 2 has a flanged disc À 5 secured to it, a spring G being retained in
compression between the flange E2 and disc A 5 to exert a pressure tending always
to keep the sleeve E at that extreme of its travel on the plunger A 3 at which it is
shown in the drawing, but permitting the sleeve to yield and remain stationary
relatively to the mould F as soon as it comes against the face thereof, whilst the
plunger A 3 moves on till its lower end is level with or near to the top of the
part F; when this occurs the operation of compression is complete. A 6 is a stud
screwed into the plunger A 3 and entering a slot E3 formed in the sleeve E
so as to limit the downward movement of the sleeve under the influence of the
Spring G

page_text: When the end E¹ of the sleeve E meets the face of the mould F in the advance
of the whole compression-device towards the latter the sleeve E is stopped, being
allowed by the spring G to yield relatively to the plunger A 3 which continues to
move onward aud effect the compression of the mass D. When the plunger A 3
recedes from the mould F the sleeve E remains in contact with the latter till the
stud A 6 reaches the top end of the slot E3 whereupon the sleeve rises with the
plunger in readiness for the succeeding operation. The details of construction,
and the arrangement of the spring and the retaining-devices for the same and for
the sleeve E may be varied without departure from this invention. The spring G
may be omitted if the sleeve E be suitably weighted or otherwise controlled so as
to tend always to move to that extreme of its travel at which it is shown in the
drawing. However the sleeve may be applied by a cam or other means, without
the spring or weight, a yielding contact being provided if necessary.
Further, the arrangement might be inverted, that is to say, a portion of the
mould provided with a yielding sleeve E could be placed in the position of the
part F and a solid plunger being then applied to the compression-device.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is ;-
1. In a compression-device for moulding-machines the combination with a plunger
or mould of a sleeve such as E for the purpose described.
2. In a compression-device for moulding-machines the combination with a plunger
or mould of a sleeve such as E a spring G and means to limit the movement of
the sleeve under the action of the spring substantially as and for the purpose
described.
3. The combination and arrangement of parts constituting the complete com-
pression-device for a moulding-machine substantially as and for the purpose
described and illustrated in the accompanying drawing.
of Ma. 1900
C. H. GRAY.
Boult & Wade,
Agents for the Applicant.