Improvements in or relating to the Manufacture of Cans, Canisters and the like.
Year: 1898

page_text: Date of Application, 22nd Feb., 1898-Accepted, 18th Feb., 1899
COMPLETE SPECIFICATION.
Improvements in or relating to the Manufacture of Cans, Canisters
and the like.
A communication from THE CANISTER MACHINE COMPANY LIMITED, of East Side,
Cross Street, Dundas, Ontario, Canada, Manufacturers.
I, ALFRED JULIUS BOULT, of 111, Hatton Garden, in the County of Middlesex,
Chartered Patent Agent, 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 making of heads for cans and canisters, and,
though not limited to any particular kind of head is more particularly designed
for that class of cans or canisters shown in Letters Patent of Great Britain,
granted to Henry Clarkson Hunter on the 8th day of March 1893, No. 5033.
In cans and canisters of this class it is desirable to remove the head
without disturbing the rim of the head, which is attached to the edge of the
can body. It is also desirable in any kind of cans, canisters and the like, in
which the contents are used for domestic purposes, that the head should be
readily removable without the use of special tools. To this end a partial removal
of the metal or material of the head, on the line of required rupture has been
devised, in a simple and economical manner,
The invention herein set forth includes the machinery for and the method of
forming such a weakened line, of uniform thinness, but without actual rupture,
this not taking place until the head is intentionally severed.
The easy removal of the head without the use of a special tool requires that
it be extremely thin on the weakened line. If this be done by stamping or by
a graving tool, there is danger that the line may be in some parts left too thick,
and that in some parts the metal may be cut to such a degree as to cause a
break. To remedy this and to rapidly form the weakened line with absolute
uniformity and certainty is the special object of my method, which consists in
gradually applying pressure upon the head. on the line to be weakened, by
means of dies movable one with relation to the other in planes a fixed distance
apart, the initial pressure being applied at the corner of the can.
The invention also includes the mechanism as herein set forth:
The invention is illustrated in the accompanying drawings, in which,
Figure 1 shows a side elevation in which parts are in section.
Figure 2 represents an end view with parts also in section.
Figures 3, 4 and 5 show detached parts, and represent details of construction.
In these drawings the bed of the machine is shown at B, supported on a
suitable standard A. It has a dovetail path in which slide a carriage C formed
with an inclined platform 2 on which is a wedge 3 whose incline is reversed to
that of the platform, so that the upper surface of the wedge is level. On this
upper surface is a stud 4 which holds the die 5. The wedge is adjustable to

page_text: raise or lower and so adjust the die in height, by means of a screw 6. The
wedge, when adjusted, is held by clamping screws 7 and 8. The die is seated
squarely and firmly on the wedge. Above the face of the die, and with its
axis in a line parallel with the face of the die, is a pressure device which may
consist of a roller 1), having a plain cylindrical bearing surface of hardened
steel. It is mounted in bearings in the sides 9, of a frame E, which is a part
of the bed casting.
On the ends of the axles of the roller are shrunk sleeves 10 and 11, and on
the ends of the roller are cog extensions 12. These cogs engage with rack
bars 13, on the carriage C, so that as the roller is turned it causes the carriage
to move under itself. The roller bears also on ribs 14 on the carriage to relieve
the bearings. On the end of the sleeve 11 is a gear which engages with a rack
bar 15, which is held in engagement with the teeth of the gear 15 by means of
an idle wheel 16, shown detached in Figure 3 and in place in Figure 1. The
back of the rack bar is grooved to engage with a rib on the idle wheel.
The lower end of the rack bar is pivoted to a wrist pin 17 on the gear wheel F
driven by a pinion G on the main driving shaft through pulley H. As the
rack bar is reciprocated it turns the roller first in one direction and then in
the opposite, causing it to reciprocate the carriage, and carry the dic back and
forth under the roller, while the roller turns. The rack bar has a curved rear
face, as shown in Figure 1 so that it is wider at the upper and lower bearing
ends, to compensate for the different angles it is compelled to assume, and always
to fit the space between the gear and the idle wheel.
The accuracy and success of the operation depends upon certainty and
uniformity in the space between the edge of the die and the opposite face of
the roller or other pressure device, in which space the weakened line is formed.
The moving roller which applies the pressure progressively, saves strain upon
the machine and therefore tends to maintain accuracy in the space between the
die edge and the pressure device, but the essential feature consists in the main-
tenance of this fixed relation between pressure devices and this may be done in
a powerful machine by the instant application of the pressure on the whole
surface. But this relation must be maintained by positive limitation of the
pressure device in its relation to the die, in the machine, itself. so that there
shall always be the same space between the pressure device and the die edge
when the machine acts on the head, whatever may be the thickness of the
sheet metal of the head.
The die is shown more clearly in section in Figure 4. It may be of any
configuration in plan required by the shape of the can. The form shown has
rounded corners and flattened sides. A rib 21 around the edge is provided with
a blunted edge adapted to form the groove in the head, which constitutes the
weakened line.
As
The die is fitted to receive the stamped head. with its outer face resting on
the rib 21. The head is put on the die, when the latter is in position shown in
Figure 1. The elevation of the die is regulated by the wedge so that a very
narrow space is left between said edge and the lower surface of the roller.
the die carrying the head passes under this roller the plate of the head is pressed
evenly and with absolute accuracy upon the die edge and the said edge is sunk
therein, a distance determined by the space between the edge and the roller
without regard to the varving thickness of the metal. This sinking of the edge
of the die into the metal by pressure leaves a very thin but compressed film of
the metal or other material of the head, and this film, though compact, and still
impervious, is capable of easy rupture.
The die is carefully arranged, as shown in Figure 5 so that the corner first
goes under the roller. and the work is thus done progressively and from the
narrowest to the widest part by pressure between surfaces having fixed limits
in relation to each other, one of these surfaces being a roller.
In a round can the same effect would be produced in any position.

page_text: Having now particularly described and ascertained the nature of the said in-
vention, as conimunicated to me by my foreign correspondents, and in what
manner the same is to be performed, I declare that what I claim is:
1-In a machine for forming a weakened line in a can head, a die having an
edge adapted to form a groove and a pressure device adapted to press positively
upon the head on the die and mechanism for limiting the space between the
pressure device and the die edge, substantially as described.
2 The die having an edge adapted to form a groove on the sheet metal and
a progressively moving pressure device, with mechanism for limiting the space
between the pressure device and the die edge, substantially as described.
Dated this 22nd day of February 1898.
BOULT & WADE,
Agents for the Applicant.