Improvements in the Means of Joining Edges of Sheet. Strip, and Thin Plate Metal, for the purpose, more especially, of Facilitating and Improving the Manufacture of Tubes, Cisterns, and other Hollow Metallic Articles.
Year: 1892

page_text: Date of Application, 28th July, 1892
Complete Specification Left, 29th Apr. 1893-Accepted, 17th June, 1993
PROVISIONAL SPECIFICATION.
Improvements in the Means of Joining Edges of Sheet. Strip, and
Thin Plate Metal, for the purpose, more especially, of Facilitating
and Improving the Manufacture of Tubes, Cisterns, and other
Hollow Metallic Articles.
I, FRANK ARTHUR WILLIAMS, of Church Road, Albrighton in the County of
Salop, Manager of Tool Works, do hereby declare the nature of this invention to
be as follows:-
Tubes, cisterns, and other hollow articles made up of sheet, strip or thin plate
metal of which one or more edges have to be securely joined together, have such
edges joined by riveting, welding, brazing or soldering. All these methods are
more or less unsatisfactory, and in some cases it is almost impracticable to make a
really pressure tight joint by any of them.
Now, according to this invention, two edges of sheet, strip or thin plate metal
are joined together by the use of a channel piece and expanding key. The
channel piece consists of a strip of metal of the required length formed channel
shape in transverse section of which the sides of the channel are undercut in shape
making the channel wider at the bottom, or at a point between the bottom and top,
than at the top. The expanding key is formed also as a strip of metal of the
length of the channel piece, and is of an arched or corresponding shape in
transverse section. The edges of the sheet, strip or thin plate metal to be joined
are turned down so that they may be placed inside the channel against the sides
thereof, respectively; and these edges are bent also, preferably, into such form
that when portions thereof are against the sides of the channel the margin thereof
beds upon the bottom of the channel on each side, respectively. The key is of a
width to allow of its being just easily placed, with its concave side inwards, within
the channel after the edges of the sheet, strip or thin plate metal bent as aforesaid
have been placed therein; and when the key has been thus placed within the
channel the crown thereof is hammered or pressed down so as to expand the key
widthways and cause it to press firmly against the portions of the sheet, strip or
thin plate metal which are against the sides of the channel and upon the margins
thereof which are upon the bottom of the channel, and thus tightly grip the sheet,
strip or thin plate metal between the edges of the key and the sides and bottom of
the channel. In joining together sheet metal in this manner the joint may be
made cold, but if the edges of thicker metal are to be joined in this manner the
margins of such edges may be heated so that the edges of the key will bed them-
selves more securely therein.
In making a tube of considerable diameter in sheet, strip or thin plate metal, it
is frequently convenient to form it of two or more strips of metal suitably curved
transversely so that when put together they make up between them the complete
circle of the tube. In building up a tube in this manner each of the longitudinal
joints may be made by the use of a channel piece and key as above described.
In testing tubes of large diameter made in the ordinary manner a considerable
quantity of water is required, as each tube must be filled before the pressure can
be put on but in the case of tubes in which the joints are made in the manner of
this invention each joint may be tested by simply filling the space between the
key and the bottom of the channel with water and subjecting the water to the
required pressure; and such a test will usually be sufficient because ordinarily
the test is made simply to ascertain that the joints will stand good.
If two edges are to be joined together at an angle, such as the edges at the
corner of a tank or of a square or polygonal tube, the outer sides of the channel
piece may be formed slanted or bevelled so as to come against and support the

page_text: sheet, strip or thin plate metal for a short width or margin thereof on each side of
the joint and in any case the sides of the channel piece may be formed to give
such support on each side of the joint.
:
The channel piece may, if desired, be formed with longitudinal ridges, or
projections more or less sharp, for the sheet, strip or thin plate metal to bed
against, in which case such ridges or projections will bed or slightly cut into the
sheet, strip or thin plate metal; similarly, the key may be formed with its edges
more or less sharp so as to bed or slightly cut into the sheet, strip or thin plate
metal.
If two curved edges of sheet, strip, or thin plate metal are to be joined together
in the manner of this invention both the channel piece and key are, of course,
curved in shape longitudinally to the curved shape of the required joint.
Dated this 27th day of July 1892
STEPHEN WATKINS,
Wolverhampton, Agent for the Applicant.
COMPLETE SPECIFICATION.
Improvements in the Means of Joining Edges of Sheet, Strip, and
Thin Plate Metal, for the purpose, more especially, of Facilitating
and Improving the Manufacture of Tubes, Cisterns, and other
Hollow Metallic Articles.
1, FRANK ARTHUR WILLIAMS, of Church Road, Albrighton in the County of
Salop, Manager of Tool Works, 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 :-
Tubes, cisterns, and other hollow articles made up of sheet, strip or thin plate
metal of which the edges are securely joined together, have, according to the usual
methods of manufacture, such edges joined by riveting, welding, brazing or
soldering. All these methods are more or less unsatisfactory, and in some cases it.
is almest impracticable to make a really pressure-tight joint by any of them; and,
moreover, the employment of such methods necessitates, as a rule, the use of
thicker metal than would be necessary if a joint could be made which was as strong
as the solid or main portion of the sheet, strip or plate metal.
Now, according to this invention, two edges of sheet, strip or thin plate metal
are joined together by the use of a channel-piece, or female holder, and expansible
key or male holder, whereby riveting, welding, brazing or soldering is avoided, and
the joint is or may be made as strong or nearly as strong as the solid portion of the
sheet, strip or plate metal. The channel-piece, or female holder, consists of a bar
of metal of the required length, formed channel-shaped in transverse section, of which
the sides of the channel are, preferably, undercut in shape making the channel
wider at the bottom, or at a point between the bottom and top, than at the top.
The key, or male holder, is formed also as a bar of metal of the length of the
channel-piece, and is of an arched or analogous shape in transverse section leaving
a hollow in its inner face so that it may be expanded in width by pressing cr
hammering down the arch or back in a direction to straighten it transversely of
the key and thus elongate it in such direction.
The edges of the sheet, strip, or plate metal to be joined are turned down so that
they may be placed inside the channel.
The key is of a width to allow of its being just casily placed, with its concave
side inwards, within the channel after the edges of the sheet, strip, or plate metal,
bent as aforesaid, have been placed therein and drawn apart from one another as
far as the sides of the channel will allow; and when the key has been thus placed
within the channel the arch or back is hammered or pressed down so as to expand
or open out the key widthways for its entire depth, but chiefly at its inner face so
that it readily adapts itself to the sectional shape of the inside of the channel, and

page_text: cause it to press firmly against the portions of the sheet, strip, or plate metal, which
are within the channel, and to tightly grip such portions between the sides of the
key and the sides of the channel for the entire, or approximately entire, depth of
the channel.
The sheet, strip, or plate metal may be coated (both outside and inside, if
desired) with a layer of other sheet metal, and the edges of such coating will be
turned down similarly as the edges of the metal which is coated thereby, and be
placed therewith in the channel; and thus there will be two (or three) thicknesses
of metal on cach side to be gripped between the sides of the key and the sides of
the channel.
The invention is illustrated, according to different modifications, by the drawings
herewith. The illustrations are given, by way of example, as shewing the
application of the invention to the joining of sheet, strip or plate metal used in
building up tubes or other articles of a circular or rounded form.
Figure 1 is a transverse section through a joint after an expansible key has been
placed within the channel-piece, but previously to such key being expanded to
complete the joint.
Figure 2 is a corresponding view to Figure 1, but shews the key expanded and
the joint consequently made.
Figure 3 is a corresponding view to Figure 2, but illustrates a joint in which the
channel-piece is on the exterior.
Figure 4 is also a corresponding view to Figure 2, but shews a modified form of
key.
Figure 5 is a reduced scale section of a tube (or other article of a circular or
rounded form) in which the sheet, strip or plate metal making up the whole
circumference in joined in two places around the circumference.
Figure 6 is a short length of the outside of the tube (or other article) shewn by
Figure 5, and shews the exterior of one of the joints.
Figure 7 is a view corresponding to Figure 1, but shews a packing of lead or
other soft metal string or wire inserted between the edges of the metal to be joined
and the sides of the channel.
Figure 8 illustrates a modification of a complete joint in the case of sheet, strip
or plate metal which is coated, both outside and inside, with a layer of other metal.
Figures 9 and 10 correspond, respectively, to Figures 1 and 2, and illustrate a
modification of the invention specially adapted for joining together the edges of
sheet metal of the lighter gauges such as No. 14 B.W.G. and thinner.
In the joint illustrated by Figures 1 and 2, A. A are two sheets, strips or plates
of metal. B is the channel-piece, or female holder, and C a key, or male holder,
formed of an arched shape in cross section which leaves a hollow c along its inner
face. The channel is shewn as formed with undercut sides. To make the joint,
the edges or margins a a of the sheet, strip or plate metal are first bent back and
inserted within the channel, as shewn by Figure 1, and the key is then placed
within the channel and between the edges a a, and the back is finally pressed or
hammered down and thereby lengthened in a direction transversely of the key and
the key is consequently expanded widthways, as shewn by Figure 2, and presses
the edges a a against the undercut sides of the channel, and grips such edges
between itself and the sides of the channel. As the crown or arch is pressed or
hammered down the sides of the key open outwards at an angle on each side, and
thus adapt themselves to the inclination of the sides of the channel, and firmly bed
up against the edges a a of the sheet, strip or plate metal for the whole depth of
the channel. The key not only firmly grips the edges a a between itself and the
sides of the channel, but does so, owing to its hollowed shape, under an elastic strain
which ensures the permanence of the grip and the consequent soundness of the joint.
The angles or corners which the sides of the channel make with the plate or sole
thereof are slanted off as shewn, or as nearly so as may be convenient in practice,
to suit the shape of the ends of the edges or margins a a which are to abut there-
against. The key illustrated by Figures 1 and 2 is formed with outwardly curved

page_text: flanges or flaps which, after the key has been expanded within the channel-piece,
are pressed or hammered down around the exterior rounded corners which the
turned-in parts of the sheet, strip or plate metal make with the main portions thereof.
In Figure 2 these flanges or flaps are shewn to have been hammered or pressed down,
the security of the joint being thus increased.
In the tube (or other article of rounded form) shewn in transverse section by
Figure 5, and of which a short length is shewn in side elevation by Figure 6, the
whole circumference is made up of two pieces of sheet, strip or plate metal. The
two pairs of edges are shewn as joined in the manner illustrated by Figures 1 and 2.
Such an article may, of course, be made up of more than two widths of sheet, strip
or plate metal, in which case the number of longitudinal joints will be increased.
And in some instances, such as in the case of tubes of say from three to ten inches
diameter, the entire circumference may be made up of a single sheet, strip or
plate bent into a tubular form, such a tube having of course only one longitudinal
joint.
In the joint illustrated by Figure 3, in which the channel piece is exterior, the
parts employed correspond to the parts illustrated by Figures 1 and 2. The
edges a a of the sheet, strip or plate metal are bent outwardly, and the key C is
put in position from the inside of a tube or other article in connection with which it
is used. The illustration shews the joint completed.
In the modified form of key shewn by Figure 4 the flanges or flaps f, of the key
shewn by Figures 1 and 2, are omitted, and in lieu thereof the outer corners fl of
the key are shewn to project slightly outwards so that they may be readily caulked
into the joint. The joint is shewn as complete, except for this caulking-in of the
corners of the key.
The parts illustrated by Figure 7 are the same as those illustrated by Figure 1,
but in this modification a lead or other soft metal string or wire d is placed against
the side of the channel on each side as shewn (and preferably in an angle thereof,
as shewn), so as to form a jointing material between the edges or margins a a of the
metal to be joined and the undercut sides of the channel; and this soft metal is
spread out to a very thin film by the pressure exerted by the expansion of the key.
Other jointing material, such for instance as packing string or red lead, may be
used if desired.
In Figure 8, which corresponds to Figure 2, the sheet, strip or plate metal A A
is shewn to be coated, both outside and inside, with a layer or sheet e of other
metal that is to say, supposing, for instance, the sheet, strip or plate metal A A
to be of steel or iron the layers of metal e may be of brass or aluminium or other
desired coating metal. The coating metal is turned in at its edges, and such edges
are placed, together with the edges of the sheet, strip or plate metal A, within the
channel and are firmly held by being gripped, together with the edges a of the
metal A, between the sides of the key and the sides of the channel.
In the joint illustrated by Figures 9 and 10 the inner sides of the channel are
formed of a Vor angular shape, as shewn, and the key C is formed with the lower
corners slanted off from the vertical sides, as shewn, so that when expanded its sides
will assume the same shape as the inner sides of the channel. As the key is
expanded within the channel, and the sides consequently opened out, sharp edges c¹
of the key press into the metal of the edges aa and force such edges to assume
the V or angular shape of the sides of the channel, as shewn by Figure 10. This
joint is more especially adapted for the lighter gauges of sheet metal such as
No. 14 B.W.G. and thinner. The sides of the key and the sides of the channel
grip between them the edges a a for the whole depth of the channel the outer sides
of the edges fitting against the inner sides of the channel and the sides of the key
fitting against the inner sides of the edges, but the grip is somewhat concentrated
at the apices of the V's or angles. It will be understood that the thinness of the
sheet metal readily permits of the edges a a being forced into the shape shewn by
Figure 10. In this modification the inner sides of the channel have somewhat the
appearance of the parts of the other modifications against which the ends of the

page_text: edges or margins a a of the sheet, strip or plate metal abut. They are, however,
for a quite distinct purpose as will be clearly understood by inspecting Figures 9
and 10. The ends of the edges a a do not abut against them, but against the base
or sole of the channel, the slanted bottom edges of the key pressing as they are
turned outwards against the lower bent portions of the edges.
Joints made in any manner above described may be made cold; but it will
frequently be an advantage to bend or turn in the edges or margins of the sheet,
strip or plate metal whilst the metal is hot.
In testing tubes of large diameter made in the ordinary manner a considerable
quantity of water is required, as each tube must be filled before the pressure can be
put on but in the case of tubes in which joints are made in the manner of this
invention each joint may be tested by simply filling the space formed by the hollow
of the key with water, and subjecting the water to the required pressure; and such
a test will usually be sufficient, because ordinarily the test is made simply to
ascertain that the joints will stand good. Moreover, if a joint is found to be leaky
at any point it can readily be made good by hammering down the key at such point
and thereby further expanding it and thus causing its sides to bear at such point
more tightly against the edges a a.
If one of the sheets, strips or plates which has been used in making up an article has
become damaged and needs replacing, the same can readily be removed by first
cutting longitudinally through the backs of the keys by which it has been joined in
place, and then removing the keys from the channel-pieces.
It will be obvious that joints as above described may be used for articles varying
greatly in shape. In using them for the longitudinal joints of taper tubes, and
other taper articles, the joints will be the same, or substantially the same, as for
parallel tubes or other parallel-sided articles. When a curved joint is required,
such as a joint passing over the end of a dome-shaped article, the channel-piece and
key are of course curved longitudinally to suit the curve of the sheets, strips or
plates to be joined. If the joint is used for the corner of a tank or cistern or like
article, the channel-piece is of course shaped on each side to allow the two sheets or
plates of metal which are joined together at such corner to pass away from the joint
in directions at right angles to one another; and the shape of the outer sides of the
channel-piece may, of course, be varied as required to suit the different shapes of
articles in respect of which the joint is used.
The term "thin plate metal" is used in a relative sense, not as meaning that the
metal must necessarily be very thin, but rather as distinguishing it from very thick
metal which could not be conveniently manipulated to form joints of the character
described. The exact thickness of the metal which may be so manipulated will, of
course, depend very largely on the proportions of the parts of the joint and on the
facilities which may be at hand for causing the necessary pressure for the expansion
of the key.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is: :―
1. The means of joining edges of sheet, strip, or thin plate metal which comprise
a channel-piece, or female holder, to receive the edges of the metal to be joined, and
a key, or male holder, which is expanded or widened within the channel, and is
thereby caused to grip and securely hold the edges of the sheet, strip, or plate metal.
between its sides and the sides of the channel, substantially as described.
2. The means of joining edges of sheet, strip, or thin plate metal which comprise
a channel-piece, or female holder, to receive the edges of the metal to be joined, and
a key, or male holder, formed of an arched or analogous shape in transverse section
which is opened out or expanded throughout its whole depth within the channel by
pressing or hammering down the back or crown thereof and is thereby caused to
grip and securely hold the edges of the sheet, strip or plate metal between its

page_text: sides and the sides of the channel under an elastic tension due to the hollowed form
of the key, substantially as described.
3. The means of joining edges of sheet, strip or thin plate metal which comprise
a channel-piece, or female holder, having undercut sides, to receive the edges of the
metal to be joined, and a key, or male holder, placed within the channel and
between the edges of the sheet, strip or plate metal and formed hollow at its inner
face and with the back thereof formed of an arched or outwardly bent shape, which
is expanded widthways throughout its entire depth, but chiefly at its inner face, by
elongating the back in a direction transversely of the key by pressing or hammering
the arch or outwardly bent part in a direction tending to straighten it, whereby the
edges of the sheet, strip or plate metal are firmly gripped between the sides of the
key and the sides of the channel, substantially as described.
4. The means of joining edges of sheet, strip or thin plate metal substantially as
described, according to different modifications, with reference to the drawings
herewith.
Dated this 27th dow of Anvil 1002
STEPHEN WATKINS,
Wolverhampton, Agent for the Applicant.