Improvements in or relating to Machines for Moulding Screw-bottle- stoppers and other Articles from Plastic Material.
Year: 1896

page_text: Date of Application, 2nd May, 1896-Accepted, 4th July, 1896
COMPLETE SPECIFICATION.
Improvements in or relating to Machines for Moulding Screw-bottle-
stoppers and other Articles from Plastic Material.
I, CHRISTIAN HAMILTON GRAY of The Indiarubber Guttapercha 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 :-
The object of this invention is the construction of machines for moulding screw
bottle-stoppers and other articles with or without screw threads from a plastic
material such for instance as rubber composition, celluloid vulcanite or the like;
hitherto such articles have been made in a series of operations partly manual and
partly mechanical, and as a whole tedious and expensive, whereas by the use of a
machine such as is hereinafter described the speed of production is increased and
the cost reduced.
In the accompanying drawings
Figure 1 is a front elevation, partly in section, of a machine constructed according
to this invention, for the manufacture of screw bottle-stoppers;
Figure 2 is an end elevation, also partly in section, of the same machine;
Figs. 3, 4 and 5, drawn to a larger scale than that of Figs. 1 and 2 are views of
details of the machine illustrated in the two figures last named,
Fig. 3 being an elevation, partly in section, of the turret or mould carrier and
other adjacent parts of the machine,
Fig. 4 being a plan of part of a toothed rack fixed on the main frame and of a
screw-mould rotatable by that rack, and
Fig. 5 being a central section of the screw-mould, with a moulded screw bottle-
stopper in place therein, the stopper being shown in elevation;
Fig. 6 is an elevation and Fig. 7 a vertical section to the same scale as that of
Fig. 3, of an alternative construction of turret and its appurtenances designed for
moulding a stopper with a corrugated or roughened flange or head.
Like letters indicate like parts throughout the drawings.
With reference first to Figs. 1 to 5, A are parts constituting the main frame of
the machine. B is the turret shaft, which rotates intermittently in bearings A¹ on
the frame A, C is the turret or mould-carrier fixed on the turret shaft B so as to
turn therewith.
The turret or mould-carrier C is of disc form in the present example; at equal
angular distances around its circumference are moulds D each shaped internally to
correspond with the exterior shape of the stopper or other article to be moulded
in it; the shape of stopper which the moulds in the present instance are intended
to produce is shown in Fig. 5, the stopper being lettered X. Each mould (sec
Figures 1 and 3) comprises a circular portion D' with a central perforation internally
screw-threaded (see Figs. 4 and 5) to mould the male screw-thread of the stopper X
and having teeth D' around its outer circumference to enable it to be rotated.
C' is a suitably divided cover-plate for each mould perforated centrally at C' and
secured to the turret; into the perforation C fits a boss D³ formed on the part D'
of the mould so that in effect the cover-plate not only keeps the part D¹ in place
but also serves as a bearing wherein it can turn. The teeth D extend beyond the
sides of the turret C and cover-plate C¹ so as to be able to gear with a fixed rack

page_text: carried on the frame A. Below the part D' and supporting the same are two
parts D' in which, jointly, the cavity for moulding the head of the stopper X is
formed. These two parts during the moulding operation occupy the position in
which they are shown in Fig. 1, but are separable, being arranged to slide away
from each other along guide-channels partly formed in the turret C by guides D'
(Fig. 3) and in part formed by the underside of the plate C'; they travel in
directions parallel with the turret shaft B. The plane of division between the
parts D is one which contains the axes of the several moulds and intersects the
axis of the turret shaft B at right angles; thus each part contains one half of
the mould for the head of the stopper. The parts D' are grooved at D' Fig. 1 for
a purpose hereinafter explained and their outer sides D' are adapted to bear
against bars E during a part of each complete rotation of the turret. The bars E
are parallel to each other and are secured in place at each side of the turret C as
shown by strong pins E' which enter recesses in the frame A; the bars are slightly
bevelled on the sides E2 and are so situated relatively to the circular path of the
moulds D that the latter in the rotation of the turret pass between them, the
parts D' of each mould being pressed towards each other by the bars E during
transit. The outer face of each bar E bears against cheek-pieces A³ on the
frame A so that the bars E are strengthened against the reaction of the parts D',
and the frame is tied by a stay rod U. The cheek-pieces A³ are formed as wedges
and are adjustable on ribs on the main frame so that they can be moved to pack up
the bars E in case of wear. Between each mould and the turret shaft B are
spindles F, one of which is appropriated to each mould and arranged to reciprocate
in a line co-axial with the mould axis, being adapted to move in a part C³ of the
turret formed to receive and guide it.
Gis a pin which is fixed in the lower end of each spindle F and arranged to
extend at opposite sides through slots C in the turret so as to be caused by cams
to move the spindle as desired. The end F¹ of each spindle F is recessed at F so
that when moved outward radially from the shaft B it can engage the head of the
stopper and prevent the stopper from rotating during one of the operations
presently to be described. C (Fig. 3) are openings in the turret for the discharge
of the moulded stopper.
H are grooved cams fixed to the frame A to more the spindles F in or out
radially as desired, by acting upon the pins G during the movement of the latter
with the rotating turret.
J are other cams in the form of curved flanged bars fixed to the frame A; the
flanges of the cams enter and operate upon the grooved portions D of the mould
parts D. K is a toothed segmental rack (see Fig. 3) by which the toothed parts D'of
the moulds are engaged and rotated during that part of their travel which lies within
the angular limit of the rack. To obviate danger of breaking the teeth of the rack K
or the teeth D of the part D' of the mould as they come together, the end K¹ of
the rack is hinged at K (Fig. 4) so that it will yield, if necessary, to allow the
teeth to gear properly. K is a spring placed between the fixed and yielding parts
of the rack to keep the latter normally in line with the fixed part. The form of
the cams H and J and the extent of the cam J and rack K are chosen in a manner
well understood by engineers, to give the parts controlled thereby the desired
movements in the order required and therefore do not need to be more specifically
described. L is a heavy weight in the form of a table caused to rise and fall
vertically above the turret C and carrying a compressor V which is weighted by
the table L and which, with the mechanism for controlling the table, is hereinafter
described,
L' is a spring knife carrier secured to the table L and having at its end a
preferably detachable cutter or knife L' in such proximity to the moulds D that
as it descends towards the adjacent mould it will shave off any of the plastic
material which projects from said mould. L' is a pendulum pivotted to the upper
part of the knife or to the table L so as to be moved up and down with the knife
and by bearing against it prevent any undue oscillation or vibration of said knife;

page_text: the knife and pendulum having different periods of vibration, each neutralizes the
vibration of the other and thus the knife is kept steady.
L' is a sliding block carried by the table L so that it can be pushed in between
the cross-piece of the frame A and the table to prevent the latter from descending.
To operate the turret and table the driving shaft M is provided; it turns in
bearings A on the frame A and has a spur-wheel M¹ fixed on near one end. N is
a shaft journalled in bearings A' in the frame A and driven from any convenient
source of power; upon it is fixed a spur-pinion N' (Fig. 2) which gears with the
spur-wheel M' so as to rotate the driving shaft M.
O is a circumferentially-grooved ratchet wheel fixed on the turret shaft B and
having at its circumference teeth O' at the same angular intervals as the moulds D
on the turret C. P is a pawl to impart intermittent motion to the ratchet wheel O
and the turret shaft B; it is pivotted on the crank pin M' of the crank M³ formed
in the driving shaft M. On one end of the pawl which is received in the groove O'
in the ratchet wheel O is a transverse pin Pi to engage the teeth O'; on the other
end of the pawl which is extended beyond the crauk-pin M2, is a counterbalance P
to keep the pin P bearing always against the teeth O'. The reciprocating
table L is caused to rise slowly and permitted to descend rapidly by cams Qof
some such profile as is indicated in Fig. 2; one of these is keyed near each end
of the driving-shaft M. R are rods adapted to be reciprocated vertically by the
cams Q, in guides A formed on the frame A. The upper ends of the rods R
carry the table L; the lower ends are of inverted T-form as shown in Fig. 2 and
are provided with wearing-strips R' to bear on the cams Q. The wearing strips
have tongues R2 to engage with the T-ends, and are so placed that the frictional
drag of the cams Q tends always to keep the tougues close against the T-ends.
The direction of rotation of the cams and other rotating parts is indicated by
arrows in Fig. 2.
V is the body of the compressor secured to the table L and projecting downwards
from it through a guide A formed on the frame A, to act on the contents of the
moulds D carried by the turret C. V1 is a screw-threaded socket in which
the screw-threaded rod V2 is adjustable to vary the effective length of the
compressor as desired. W is a lock-nut to secure the rod V2 after adjustment.
To the lower end of the red V2 is secured the plunger V3 and in the lower end V*
of the plunger or a die carried by it and readily removable therefrom is a concave
or other matrix shaped to impart the desired form, imprint or pattern to that part
of the plastic "blank" with which it comes in contact. Y is a sleeve encircling
the plunger projecting in advance of the same and having its end Y' shaped to fit
close against the opposed face of the mould D below it. In the present example
the sleeve is provided at its upper end with a flange Y2 and the rod V2 has a
flanged disc V secured to it, a spring Z being retained in compression between
the flange Y' and disc V to exert a pressure tending always to keep the sleeve Y
at that extreme of its travel on the plunger V at which it is shown in the drawing,
but permitting the sleeve to yield and remain stationary relatively to the mould D
as soon as it comes against the face thereof whilst the plunger V3 moves on till its
lower end is level with or near to the top of the part D; when this occurs the
operation of compression is complete. V is a stud screwed into the plunger Va
and entering a slot Y formed in the sleeve Y so as to limit the downward
movemment of the sleeve under the influence of the spring Z. The spring Z
might be omitted if the extension Y were suitably weighted or otherwise con-
trolled so as to tend always to move to that extreme of its travel at which it is
shown in the drawing.
Further, the arrangement might be inverted, that is to say, a portion of the
mould provided with a yielding sleeve Y could be placed in the position of
the part D a solid plunger being then applied to the compression-device V.
The manufacture of a screw bottle-stopper by this machine is effected as
follows;-
A preferably cylindrical piece or plug of softened vulcanite of suitable size is

page_text: placed in each mould D just before it passes under the plunger V. The shaft M
being driven continuously and at uniform speed by the shaft N, causes the pawl P
to operate the turret shaft B intermittently by way of the ratchet wheel O to
bring the moulds D in succession under the plunger V, below which every mould
makes a momentary pause. During this pause cams Q permit the heavy table L
to descend rapidly and bring down the plunger V upon the piece of vulcanite
(which projects from the mould orifice) and force it into the mould cavity in the
parts D and D so that it takes the form of the space bounded by the walls of that
cavity and the lower end of the plunger V, thus in one operation the stopper is
completely moulded.
When the end Y¹ of the sleeve Y meets the face of the mould D in the advance
of the whole compression-device V towards the latter the sleeve Y is stopped,
being allowed by the spring Z to yield relatively to the plunger V which continues
to move onward and effect the compression of the mass in the mould. During the
moulding operation the bars E bear against the parts D of the mould to resist
the bursting tendency induced by the compression of its contents. Next, the
plunger Vis slowly raised with the table L by the eams Q, in readiness for
operating on the plastic or softened material in the next succeeding mould. When
the plunger Vs recedes from the mould D the sleeve Y' remains in contact with the
latter till the stud V reaches the top end of the slot Y whereupon the sleeve rises
with the plunger in readiness for the succeeding operation, and the turret C moves
onward for another portiou of a revolution, taking the mould containing the
moulded stopper into the range of the cam J and towards the rack K; these
and the cams H operate as follows during the successive movements of the
turret ;-
First the cams J cause the mould sections D to move apart, clear of the head of
the stopper, and next the cams H act on the pin G to move the spindle F radially
outward from the shaft B until the recessed end of the spindle F, reaches the
head X (Fig. 5) of the moulded stopper X which is received in the cavity.F.
By the time that this movement of the spindle F is completed the teeth D² on the
portion D of the mould are brought by the turret into gear with the fixed rack K
and the part D is rotated; this rotation screws the moulded stopper out of the
part D towards the centre of the turret, inasmuch as the stopper itself being
engaged by the rod F is prevented from rotating. The rod F is moved inward
towards the centre of the turret by the cams H, at preferably the same speed as
that at which the stopper is being unscrewed in the same direction by the part D
but to a greater distance, so that the stopper after being screwed completely out of
the part D will fall away from the head Ft of the spindle F, and out of the
opening C in the turret into a shoot or receptacle not shown in the drawings; it
should be understood that at the time this discharging operation occurs the
spindle F will have moved with the turret so as to lie in some such position as is
indicated at Y (Fig. 2) and consequently the released stopper falls away from the
turret. As the mould moves onward to be again charged the parts thereof and
the spindle F are caused by the cams H and J to reassume the relative positions
in which they are shown in Fig. 1 and after the mould is re-charged a similar
cycle of operations ensues; the several moulds commence and complete their cycles
in turn as will be readily understood.
In the alternative construction of turret illustrated in Figs. 6 and 7 which is
specially devised for making screw bottle stoppers with heads of circular form,
the flanged and ribbed or milled circumference X of the stopper shown in that
figure is formed by a portion D of the mould which in the former example
(Fig. 2) was divided but in this example is made in one piece, the central
perforation therein being tapered to facilitate the exit of the completed stopper.
Externally the part D is flanged and so secured that it can be readily removed
and replaced by dies of the same external but different internal form. The convex
part of the stopper-head is shaped by a plunger such as V3 in Fig. 2 which is given
a concave end. The screw-threaded stem X³ of the stopper is moulded in the

page_text: cavity of a die D' which is rotatable in bearings in the turret C and has a bevel-
wheel D' fixed to it and extending beyond the sides of the turret. This bevel
wheel is adapted to engage with a continuous toothed rack K fixed on the main
frame of the machine so that after the stopper is moulded, the bevel wheel D' is
rotated to screw the stopper out of the mould. To prevent the stopper from rotating
whilst being thus unscrewed I form the mould portion D' in one with a bar D³,
Fig. 7, with which it is free to move to about the extent of twice the length of the
stopper stem X inwards and outwards en lines radiating from the axis of the
turret shaft Beach of the bars D' carries a projection or anti-friction roller D
which engages with the groove of a fixed and conveniently circular cam S arranged
eccentrically to the axis of the turret shaft B.
During the descent of the plunger V the turret is stationary as before described
and consequently the die Di has no movement about its axis. As soon as the
moulding operation is completed and the plunger V ascends the turret C is moved
outwards as indicated by the arrow in the drawing, and the wheel D³ and die D'
are consequently rotated and by reason of the screw thread on the stopper the die
moves the latter outwards, the stopper ineanwhile being prevented from rotating by
the mould portion D' to which its head for the time being adheres.
By the last described arrangement the mould portions D' although always
brought at the proper moment to their moulding position at the upper part of the
turret, are, by the eccentric cam S gradually moved outwards during their descent
until they are quite clear of the turret at the lower part of the latter, at which part
a bar or tappet T is located, this bar being provided with an arm T' extending
upwards into the path of the table L so that at each descent of the latter the
tappet T is moved downwards and the stopper then beneath it is driven out of the
mould part D. After this ejection the cam or eccentric S returns the part D* to
the position in which it is shown in Fig. 1, that is to say to its moulding position.
The cam or eccentric S is adapted to move the mould part D' outwards at a speed
corresponding to that at which the stopper is moved outwards by the rotation of
the mould part D'; in Fig. 6 wherein the wheel D' is adapted to rotate eight times
at each rotation of the turret C, one eighth of the rotation of the latter is sufficient
to free the stopper from the mould D. A hydraulic or steam press or a spring or
springs may be employed instead of the table L to exert the desired pressure ou
the compressor V and its plunger V; and instead of the disc type of mould-
carrier, a belt or a series of links or a reciprocating bar, or a table turning in a
horizontal plane can be employed to carry the moulds and present them in turn to
the compressor. The racks K herein before referred to may be carried on springs
or other elastic supports to ensure easy working of the wheels with which they
gear and to avoid risk of breaking the teeth of the rack and wheels.
Although this invention is hereinbefore described with reference by way of
example to the manufacture of screw bottle-stoppers, it is applicable with equal
advantage to the manufacture from plastic material of other articles with or
without screw threads. Moreover the plungers V may be arranged in a series,
descending simultaneously to operate upon material in moulds the latter being
arranged in groups upon the mould-carrier instead of singly.
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 moulding-machine for rubber composition celluloid or the like the
combination with moulds and a compressor of a mould-carrier movable to bring
the moulds in turn into the path of the compressor.
2. In a moulding-machine for rubber composition celluloid or the like the
combination with moulds and a compressor of a mould-carrier such as Cand
mechanism to operate and control the compressor and bring the moulds in turn into
its path for the purpose described.
3. In a moulding-machine for rubber composition celluloid or the like a mould

page_text: such as D comprising a rotatable member such as D₁ and a member or separable
members such as D substantially as and for the purpose described.
4. In a moulding-machine for rubber composition celluloid or the like the
combination with a mould such as D of a device such as F for the purpose
described.
5. In a moulding-machine for rubber composition celluloid or the like such as
described the combination with a mould-carrier such as C having moulds such as D
of stationary cams such as H and J and fixed rack K with or without the bars E
substantially as and for the purpose described.
6. In a moulding-machine for rubber composition celluloid or the like ratchet
and pawl mechanism substantially such as described for operating the mould-
carrier.
7. In a moulding-machine for rubber composition celluloid or the like a knife
such as L moving with the compressor with or without a pendulum L³ operating
substantially as and for the purpose described.
8. In a moulding-machine for rubber composition celluloid or the like a fixed
rack such as K with a yielding portion K' substantially as and for the purpose
described.
9. In a moulding-machine for rubber composition celluloid or the like a rack such
as K so supported as to be capable of yielding for the purpose described.
10. In a moulding-machine for rubber composition celluloid or the like removing
n moulded screw from its mould while still in the machine by rotating the mould
while the screw is held or by rotating the screw while the mould is held.
11. In a moulding-machine for rubber composition celluloid or the like a mould
such as D substantially as and for the purpose described and illustrated in
Figures 13 and 5 or Figure 6 of the accompanying drawings.
12. In a moulding-machine for rubber composition celluloid or the like a
turret C substantially as and for the purpose described and illustrated in Figure 3
or Figures 6 and 7 of the accompanying drawings.
13. The combination and arrangement of parts constituting the complete
moulding machine substantially as and for the purpose described and illustrated
in Figures 1 and 2 of the accompanying drawings.
Dated this 1st day of May 1896.
C. H. GRAY.
Boult & Wade,
Agents for the Applicant.