Year: 1888

page_text: 1, ALFRED JULIUS BOULT of 323 High Holborn, in the County of Middlesex,
M.I.M.E. 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 improvements in that class of cylinders which are composed
of metal strips coiled into a tube. It is particularly an improvement on the invention
described in Letters Patent of the United States heretofore granted, numbered 285,576.
The main object of this invention is to give a smooth uniform outer surface to the
cylinder and secondly to give increased strength thereto.
In
In the drawings, Fig. 1. is a perspective view of a partially formed cylinder and
illustrates one mode of carrying out this invention; Fig. 2. is a longitudinal section
of this cylinder on a larger scale than Fig. 1. Fig. 3. is a sectional view of a piece
of the metal ribbon prepared for winding; Figs. 4 & 5. are modified forms of cylinders.
In the Letters Patent referred to above, I have described a mode of making
cylinders by coiling a ribbon of sheet metal, with the edges close together to the form
of a tube, then coiling upon this tube another ribbon, breaking joints with the first
and finally uniting the coils and the tubular formed bands together, by solder.
carrying out that invention the edges of the metal were allowed to abut against cach
other and experience proves it difficult to wind the metal strips with their edges
abutting to each other closely, and the difficulty is increased by the practical inability
of cutting or trimming the metal to an absolutely straight edge. It generally happens
therefore, by reason of improper trimming, coiling or otherwise, that openings appear
between the abutting edges of the metal and these openings, although they become
close by solder, during the operation of uniting the bands together, tend first, to limit
the strength of the cylinder and second to form a wearing surface composed of two

page_text: metals, solder and steel, and for many uses, this is decidedly objectionable and un-
satisfactory and to obviate such difficulties and objections, is the object of this invention.
To this end the metal ribbon is given a beveled edge a, and an obversely beveled
edge e which may be done by grinding off the metal along the edges of the ribbon, as
shown in figure 3 of the accompanying drawings. The ribbon, thus prepared, is next
coiled, spirally, to the form of a tube; the two beveled edges of the metal are thus
brought together and lapped, one over the other, and are united by solder. A cylinder
formed in this manner presents a smooth uniform outer surface and has strength
suflicient for many purposes, but when exceptional strength is required a second
ribbon of sheet metal may be coiled upon the first tube, the two being allowed to
break joints with each other and the whole united together with solder by immersion
in a bath of the molten metal. In such case, the ribbon last coiled, is the only one
that compasses the outer surface of the cylinder and therefore, it is immaterial, in
such cases, except for purposes of strength whether the inner coils have their edges
lapped or abutted together. Greater strength will be obtained, of course, when all
edges are lapped, and therefore it is preferable to form them in this manner, though
in the drawings I have represented each of these three formations.
Having now particularly described and ascertained the nature of the said invention,
as communicated to me by my foreign correspondent, and in what manner the same
is to be performed, 1 declare that what I claim is :-
1. A sheet metal cylinder composed of a ribbon of sheet metal coiled spirally to the
form of a tube, the edges of the metal being beveled and lapped, one over the other,
and united by solder, substantially as described.
2. A sheet metal cylinder composed of a ribbon of sheet metal coiled spirally upon
a second tube or band also formed of sheet metal, the outer and inner bands breaking
joints with each other and the edges of the outer band being beveled and lapped and
the whole united together by solder, substantially as specified.
3. A sheet metal cylinder composed of two or more ribbons of sheet metal coiled
spirally one upon the other and breaking joints one with the other, substantially as
described the edges of the said metal ribbons being beveled and lapped and the whole
united together with solder substantially as set forth.
Dated this 9th day of March 1888.