Improvements in Sheet Metal Cans.
Year: 1895

page_text: Date of Application, 18 h Apr., 1895-Accepted, 18th May, 1895
[Communicated from abroad by JOHN LEE, of San Mateo, in the County of
San Mateo and State of California, United States of America, Manufacturer.]
Improvements in Sheet Metal Cans.
I, HENRY HARRIS LAKE, of the Firm of Haseltine, Lake & Co., Patent
Agents, 45 Southampton Buildings, in the County of Middlesex, 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:-
My invention relates to sheet metal cans, and more particularly to the
construction of what is known as tearing strip or key opening cans.
Heretofore these tearing strip or key opening cans have usually been made by
providing the body or head portion of the can with a tearing strip marked off or
bounded by one or more scores, beads or weakened lines along which the strip
tears or separates; the tearing strip being furnished with a projecting tongue to
start the winding. This projecting tongue is usually made integral with the
tearing strip, but it has sometimes been made of a separate short piece soldered to
the tearing strip. The provision of the can with weakened lines to mark off the
tearing strip requires a special operation in the manufacture of the can, thus
adding materially to the cost of manufacture; and the provision of the projecting
tongue, if it be made integral with the tearing strip, requires a special construction
of can making machinery and dies, and also adds considerably to the amount of
stock or tin plate required to make. the cans; and if the tongues are made in a
separate piece the soldering of the same in place is a somewhat slow and expensive
operation, requiring care to prevent the strip being soldered fast, throughout its
whole length, and unless specially located interfering with the usual rapid and
inexpensive method of soldering the end and side seams of the can itself. And
the scored or weakened lines in the can frequently so diminish the strength of the
can as to cause them to burst in the processing, or to render them liable to injury
in handling and shipment, especially if the weakened lines are not formed with the
greatest care.
The object of my invention is to provide a key opening can of a simple, cheap
and practical construction; which may be opened easily and perfectly by winding
a tearing strip around a key; in which the full strength of the ordinary can will be
preserved; which require no special score, beads or weakened lines to enable the
can to be opened; which may be made by the ordinary dies, machinery and process
of manufacture; and in which the separate projecting tongue may be soldered in
place by the same operation by which the head itself is soldered to the body.
I have discovered, and herein my invention consists, that the ordinary right angle
flange of the can head, which fits outside the can body, will of itself, without any
special provision or scores or weakened lines serve perfectly as a tearing strip; anil
that the same will separate perfectly and naturally at the corner between said
flange and the flat or disk portion of the head; I find also that a separate tongue
to begin the winding may be conveniently attached and soldered in place at the
same time the head is soldered to the body in the usual manner by rolling in an
inclined position through a bath of molten solder, by the simple expedient of
making the tongue of a partially tinued and partially untinned strip, so that the
untinued portion which projects outside will not be soldered fast to the periphery

page_text: of the can while the tinned portion will be soldered fast. By this simple expedient
I securely and properly solder the tongue in place by one and the same operation
with that employed for soldering the head to the body and without any additional
labour or expense.
In utilizing the exterior flange of the can head as the tearing
strip, the key around which the flange or strip is being wound is held at an angle
to the axis of the can, so as to cause the lower or free edge of this flange or strip
to be separated from the body in advance of the upper edge of this flange or strip
where it separates from the flat or disk portion of the head. This causes the
tearing to be done by a kind of shearing action, and prevents any tendency of the
strip to run out. By separating the lower edge of the strip first, or in advance of
its upper edge the tendency is to cause the line of tear to run or incline in the
apposite direction from the free edge of the strip, that is to say to run or incline
toward the flat or disk portion of the head. And as the line of tear thus tending
to run or incline toward the disk cannot run into the circular disk portion of the
head; it of course follows that the flange or strip must continually separate at the
corner between the flange and circular disk portion of the head.
In practising any invention I make the corner uniting the flange and disk of
the head as near a right angle corner as can conveniently be done, that is to say I
prefer not to make the corner greatly rounded, as is sometimes done in the making
of caus.
My invention also cousists in the novel devices and novel combinations of parts
and devices herein shown and described and more particularly pointed out in the
claims.
In the accompanying drawing, which forms a part of this Specification, and in
which similar letters of reference indicate like parts throughout all the figures,
Figure 1 is a perspective view of a can embodying my invention; Figure 2
is a similar view illustrating the method of opening the can by winding the
flange of the head about a key held at an angle or inclination to the axis of the
can;
Figure 3 is a detail sectional view on line 3-3 of Figure 1;
Figure 4 is a detail sectional view at right angles to the axis of the can;
Figure 5 is a detail plan view of the separate tongue strip, the shaded portion
indicating the black or untinned part and the plain portion indicating the tinned
part of the tongue strip; and
Figure 6 is a detail perspective view illustrating the method or process of
soldering the separate tongue strip in place by the act of soldering the end seam
of the can in the usual manner by rolling the can through a solder bath.
The
In the drawing A represents the can body and B the can head, the same being
furnished with the usual flange & fitting outside the body. The can head flange bis
provided at one point with a slit or cut across the same, at which the separate
tongue D is inserted between the can head flange and can body, leaving a portion d
of the tongue strip projecting outside for attachment to the key F to start the
winding. The portion d¹ of the tearing strip D, which is inserted between th
flange of the can head and the can body, is tinned or otherwise prepared so that it
may be soldered to the can head and body, and make a perfect closure.
portion d of the tongue D however, which projects outside and is to remain free
from the can so that the key may be conveniently applied is of plain or untinned
sheet steel or iron or otherwise prepared, so that when the end seam of the can is
rolled in a bath of molten solder or otherwise brought in contact with the solder in
the act of soldering the head to the body, this outside untinned portion of the
tongue D will not take the solder or be soldered to the exterior surface of the can.
I am thus enabled by the simple act of soldering the head and body together to
also at the same time solder the separate tongue D in place, and leave its projecting
end d entirely free and unattached; and this without any extra care or expense. To
limit the extent to which the tongue D may be inserted in the slit b', I preferably
provide it with a shoulder or offset d. And the flange b of the can head may also
be preferably provided with a slight offset, shoulder or pocket & to receive the

page_text: tongue strip. Ordinarily the frictional fit, bite or clamping action between the
flange of the can head and the can body, especially if the can heads are made tight
fitting, as they should be, will be sufficient in itself to properly hold or clamp the
tongue strip D in place during the soldering operation or until it is soldered fast;:
but if preferred the strip D may be additionally secured to the flange b by piercing and
clinching the parts together, as indicated in Fig. 4 at b* d'. The can head B is
also preferably provided with the usual countersunk portion 68, but the portion be
which is united by the corner with the flange should be a flat plain disk, as
indicated in the drawing.
By simply holding the key F at an angle to the axis of the can during the
winding operation, as indicated in Fig. 2, the lower free edge 68 of the flange will
separate from the body A of the can in advance of the upper or corner edge b' of
the flange. But this same method of tearing the flange from the can by causing
its free or lower edge to separate in advance of its upper edge, may be effected in
other ways, as for example by making the key tapering.
:
By thus utilizing the corner, or change in direction, between the cylindrical
flange of the can head and the flat or disk portion of the head, itself, as the line of
separation for the tongued tearing strip, I entirely avoid the necessity for weakening
the can with any special score or weakened line." It will of course be understood
that this corner or change in direction between the flange of the head and the disk
portion thereof is necessarily present in all cans having outside fitting flanged
heads and while it may be true that the act of making or drawing up such
Hanged heads may slightly weaken the strength of the stock in the flange, and
possibly also to some extent too at the corner where the drawing operation
terminates and is less severe; still, as this slight weakening is only the ordinary
weakening of such flange or corner incident to every can including those having no
self opening construction or tongued tearing strip of any kind, it will of course be
understood that by use of the words: "unscored," "unweakened," "no score or
weakened line "I do not mean thereby the slight weakening incident to the bending
of the stock to give the necessary change of direction or to form the corner between
the disk and flange of the head. Nor do I mean thereby that the head of my can
has not the ordinary right angle flange and the ordinary corner uniting such flange
with the flat disk-portion of the head. On the contrary, what I do mean by these
words is what is ordinarily understood by those skilled in the art, viz.: the usual
special score or weakened lines heretofore employed for marking off the tearing
strip.
In my can, while it may possibly be true that the stock may possibly be slightly
weakened at the corner uniting the flange and the disk portion of the head, it is
really the right angle change in direction between the cylindrical head and the disk,
and the rigid support given by the edge of the disk directly at the line of separation
to the key and coil in the act of winding the flange. about the key and separating
the flange from the disk, which, I think, enables such corner or change of direction
to serve without any special score or special weakening as an efficient line of
separation for a tearing strip. At least this is the best explanation I am now able
to give of the reason why my invention does actually operate, and since making the
discovery I have given some considerable time, study and experimenting to the
matter. My experiments lead me to believe that if the flange of the head be
formed, or could be formed, without weakening the stock at all at the corner, the
corner may be utilized just the same as an efficient line of separation.
Having now particularly described and ascertained the nature of my said iuven-
tion, and in what manner the same is to be performed, as communicated to me by
my foreign correspondent, I declare that what I claim is :-
1st. A sheet metal can having no scores or weakened line, comprising the
body A and head B furnished with a flange fitting outside of the body and
soldered thereto, said can head flange & being provided with a projecting tongue
and serving itself as a tearing strip for opening the can by separating from the

page_text: flat or disk portion of the head at the corner uniting the flange therewith,
substantially as specified.
2nd. The combination with can body A of head B having outside fitting
flange b furnished with a slit or cut across the same, said head B having no
scored or weakened line, and a separate tongue strip D in part inserted between
the flange of the can head and the can body and soldered thereto, the corner
uniting the flange of the head with the flat or disk portion thereof itself serving
as the line of separation of the flange from the head in coiling said flange as a
tearing strip around the key, substantially as specified.
3rd. The combination with a can body A of head B having outside fitting flange b
furnished with a slit or cut across the same, said head B having no scored or
weakened line, and a separate tongue strip D in part inserted between the flange
of the can head and the can body and soldered thereto, the outside portion of said
tongue strip being untinned and the inside portion tinned, the corner uniting the
flange of the head with the flange or disk portion thereof itself serving as the line
of separation of the flange from the head in coiling said flange as a tearing strip
around the key, substantially as specified.
4th. The combination with can body A of head B having outside fitting flange b
furnished with a slit or cut across the same, said head B having no scored or
weakened line, and a separate tongue strip D in part inserted between the flange of
the can head and the can body and soldered thereto, said tongue strip and can head
flange being pierced and clinched together, the simple corner uniting the flange
and the flat or disk portion of the head itself serving as the line of separation,
substantially as specified.
5th. The combination with can body A of head B having outside fitting flange b
furnished with a slit or cut across the same, said head B having no scored or
weakened line, and a separate tongue strip D in part inserted between the flauge of
the can head and the can body and soldered thereto, said tongue strip D being
provided. with an offset d', the simple corner uniting the flange and the flat or
disk portion of the head itself serving as the line of separation, substantially as
specified.
6th. The combination with can body A of head B having outside fitting flange b
furnished with a slit or cut across the same, said head B having no scored or
weakened line, and a separate tongue strip D in part inserted between the flange of
the can head and the can body and soldered thereto, said tongue strip D being
provided with an offset d³, and said can head flange having an offset or pocket b³,
the simple corner uniting the flange and the flat or disk portion of the head itself
serving as the line of separation, substantially as specified.
Dated this 18th day of April 1895.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.