Improvements in or relating to Tubes suitable for the Construction of Velocipede Frames and similar Structures.
Year: 1897

page_text: Date of Application, 16th June, 1897
Complete Specification Left, 16th Mar., 1898-Accepted, 16th Apr., 1898
PROVISIONAL SPECIFICATION.
Improvements in or relating to Tubes suitable for the Construction
of Velocipede Frames and similar Structures.
I, ARCHIBALD SHARP, of 13, Fairlawn Grove, Chiswick, in the County of
Middlesex, Engineer, do hereby declare the nature of this invention to be as
follows:-
My invention relates to tubes suitable for the construction of velocipede frames
and similar structures and has for its principal object the combination of rigidity
and lightness in a high degree and the provision of increased resistance to bending
under strains in certain directions to which individual members of the frame or
the like are specially subjected.
In the case of a rear driving safety bicycle, for instance, there is a considerable
lateral strain on the chain stays and in order to obtain a narrow tread it is advan-
tageous to keep these tubes as narrow as possible thus necessitating the arranging
of the metal, in a tube of even gauge, comparatively close to the neutral axis.
To attain my object I preferably employ high carbon sheet steel, nickel sheet
steel or the like. Each tube consists preferably of two strips of material, and the
cross section of each strip is brought to the form of three sides of a rectangle. The
two strips are then placed together with their sides overlapping. The section of
the tube so formed is therefore rectangular, one pair of opposite sides having a
double thickness, and the other pair of opposite sides a single thickness.
One strip
may be slightly wider than the other, so that both sides of the narrower strip will
lie within or between the sides of the wider strip; or the strips may be of equal
width so that one side of each strip' will lie within the adjacent side of the other
and the remaining side of each will lie outside the remaining side of the other.
Or the strips may be made wider and with their sides doubled back on them-
selves, inwardly and outwardly, so that if the strips be slid together lengthwise the
respective folds will interlock and hold the two strips together. In this case one
pair of opposite sides of the rectangular tube will be four times the thickness of
the other pair of opposite sides.
Or a weldless or welded tube of large diameter may be drawn down through dies,
pressed or otherwise suitably treated so that two opposite sides of the (preferably
rectangular) tube will be folded to a treble thickness and the remaining parts left
single.
The overlapping parts of the various tubes above referred to may be secured
together by brazing, soldering, rivetting, electric welding, seaming or other means
suitable for the purpose. And to further strengthen such tubes additional strips
of material may be enclosed and secured within the said overlapping parts.
I do not confine myself to rectangular sections for the tubes though such are
usually preferable as then the bulk of the material, in the girders constituted by,

page_text: the tubes may be located in the flanges and the webs left light in the most economical
manner.
Dated the 15th day of June 1897
G. DOUGLAS LEECHMAN,
18, Hertford Street, Coventry, 75, Chancery Lane, London, W.C., and
49, Middle Abbey Street, Dublin, Patent Agent for the Applicant.
Improvements in or relating to Tubes suitable for the Construction
of Velocipede Frames and similar Structures.
I, ARCHIBALD SHARP, of 13, Fairlawn Grove, Chiswick, in the County of
Middlesex, Engineer, 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 tubes suitable for the construction of velocipede frames
and similar structures and has for its principal objects the combination of rigidity
and lightness in a high degree and the provision of increased resistance to bending
under strains in certain directions to which individual members of the frame or
the like are specially subjected.
In the case of a rear driving safety bicycle, for instance, there is a considerable
lateral strain on the chain stays and in order to obtain a narrow tread it is advan-
⚫tageous to keep these tubes as narrow as possible thus necessitating the arranging
of the metal, in' a tube of even gauge comparatively close to the neutral axis.
The accompanying drawings show transverse sections of various tubes and parts
of tubes constructed according to my invention. The constituent members of the
tubes are shown somewhat separate for clearness. Like numerals refer to like
parts throughout the drawings.
.
preferably employ high carbon sheet steel, nickel sheet steel or the like for the
construction of my tubes. Each tube consists preferably of two strips 2, 3 of the
material, and the cross section of each strip is brought to the form of three sides of
a rectangle or of a form approximating to that of a rectangle. The two strips
are then placed together with their sides overlapping (Figs. II, III). The section
of the tube so formed is therefore rectangular or approximately rectangular; one
pair (4) of opposite sides has a double thickness, and the other pair 5 of opposite
sides has a single thickness. One strip (3) may be slightly wider than the other (2)
so that both sides of the narrower strip will lie within or between the sides of the
wider strip as in Fig. II. Or the strips may be of equal width so that one side
of each strip will lie within the adjacent side of the other and the remaining side of
each will lie outside the remaining side of the other as in Fig. III. In this case
one side of each strip may be slightly deeper than the other, as shown.
Or the strips may be made wider and with the sides of one, say 2, doubled back 4
on themselves inwardly, and the sides of the other (3) doubled on themselves out-
wardly. Then the strips are slid together lengthwise so that the respective folds
will interlock and hold the two strips together as shown in Fig. IV. In this case
the pair 5 of opposite sides of the tube are four times the thickness of the other
pair 4.
#
Or a weldless or welded tube of large diameter may be drawn down through
dies, pressed or otherwise suitably treated so that two opposite sides (5) of the
4

page_text: (preferably rectangular) or approximately rectangular) tube will be folded to a
treble thickness and the remaining parts 4 left single as shown in Fig. V.
To further strengthen such tubes additional strips 6 of suitable material may be
enclosed and secured within the overlapping parts, as shown, for example, in
Fig. VI.
The said overlapping parts of the various tubes above referred to may be secured
together by brazing, soldering, rivetting, electric welding, seaming or other means
suitable for the purpose, such as are employed by manufacturers of hollow rims
for cycle and other wheels.
I prefer to construct my tubes of rectangular or approximately rectangular section,
as then the bulk of the material in the girders constituted by the tubes is located in
the flanges (5) and the webs (4) are left light in the most economical manner. But
instead of an accurately rectangular form it as preferable, in practice to make
the tube with slightly bowed surfaces and rounded corners as shown diagram-
matically in Fig. VII. This construction prevents injury which might arise from
bending the material at sharp angles and from thinning the edges in polishing.
Further, the brazing or the like and the polishing are facilitated as the material
is much less liable to buckle when curved than when straight.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is:-
1. Tubes, for velocipede frames and similar structures, having one pair of opposite
sides of single thickness and the other pair of opposite sides of double or more
thickness, constructed by securing together two trough-sectioned strips of material,
substantially as described and for the purpose set forth.
2. Tubes, for velocipede frames and similar structures, having one pair of opposite
sides of single thickness, and the other pair of opposite sides of triple thickness,
constructed by suitably treating weldless or welded tubes, substantially as described
and for the purpose set forth.
3. In tubes of the kinds referred to in the preceding claiming clauses, the employ-
ment of one or more additional strips, such additional strips being enclosed and
secured within the overlapping parts of the said tubes, and as illustrated by way
of example in Figure VI of the accompanying drawings.
4. Tubes for velocipede frames and similar structures constructed substantially
as herein described with reference to the several figures of the accompanying
drawings
Dated this 15th day of March 1898.
G. DOUGLAS LEECHMAN,
18, Hertford Street, Coventry, 75, Chancery Lane, London, W.C., and
9, Exchange Chambers, New Street, Birmingham,
Patent Agent for the Applicant.