Improvements in Metal Tubes or Bars, especially applicable to the Frames of Velocipedes.
Year: 1893

page_text: Date of Application, 23rd May, 1893
Complete Specification Left, 23rd Feb., 1894-Accepted, 21st Apr., 1894
PROVISIONAL SPECIFICATION.
Improvements in Metal Tubes or Bars, especially applicable to the
Frames of Velocipedes.
I, WILLIAM BORTHWICK SMITH, of 139, Cannon Street, in the City of
London, Engineer, do hereby declare the nature of this invention to be as
follows:-
This invention relates to metal tubes or bars, and more especially to such tubes
or bars when used for the frames or other parts of bicycles, tricycles, or other
velocipedes, and it has for its object novel methods of making such frames, by which
they are very strong, light, durable, and inexpensive.
Supposing that the invention is to be applied to the frame of a bicycle or other
velocipede, which is ordinarily made of steel tube of suitable diameter and of
uniform thickness, by the present invention I make such tube so that the parts
which receive strain when in use are so proportioned that the strain is properly
distributed over them.
When such tube is used for instance to form the framing of a velocipede, one
part of its section is usually under compression whilst the other part is in tension,
and in order that the strength of the tube may be properly proportioned, I make
the part of the tube under compression of greater sectional area that the other part,
the bore of the tube being nearer the latter.
And in order further to increase the vertical strength, I sometimes make the
vertical depth of the tube greater than its horizontal width, its section therefore
being more or less elliptical.
The improved tubes may be formed by rolling and drawing in the usual way.
In a modified form I make the bar in the form of a flanged beam or girder,
instead of a tube, the vertical plate of the beam having a horizontal flange at its
upper and lower edge, the upper one having preferably the greater sectional area.
In order to improve the appearance of such a beam I prefer to curve the edges of
the upper flange downward and of the lower flange upward so that their edges
nearly or quite meet, the periphery of the tube so formed being circular or nearly
so whilst great strength is obtained by means of the vertical central flange.
The upper and lower flanges are preferably made thicker at the centre where
they join the vertical flange, than at their edges which are gradually tapered down.
The longitudinal edges of the upper and lower flanges where they meet, may be
brazed or soldered together.
The tube or hollow bar of the kind described, may be made of sheet metal, such
as steel, folded into the shape required. For instance, a strip of steel of sufficient
width may be bent into the shapes shewn in Figures 1 and 2 in the accompanying
drawing.
Or the edges of the bent strip may be made to meet in the centre of the top or
the bottom flange. Or the strip may be bent into the form shewn in Figure 3,
and in all cases the edges of the strip where they meet may be brazed or soldered
together.
In order to join the ends of the tube or bar formed as described to other bars or
fittings, a junction piece may be used consisting of a flange fitting for a sufficient
distance into the end of the tube, the flange being divided in the part which so fits
into the tube so that one part fits upon one side and the other part upon the other
side of the central plate of the tube.
The outer end of the plug is properly shaped to receive and attach any other
tube or fitting which is to be fixed to the inner tube, and it is fixed by rivets screws

page_text: or brazing. Or the central plate may project beyond the flanges, and be rivetted
into and joined to other tubes or fittings.
I do not confine myself to any precise details of shape and proportion of the
different parts, which may be varied more or less to suit different circumstances.
The improved tube or bar is very strong, light, and easily made, and it may be
applied to other purposes as well as to the frames of velocipedes.
Dated this 23rd day of May 1893.
EDWARDS & Co.,
35, Southampton Buildings, London, Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Metal Tubes or Bars, especially applicable to the
Frames of Velocipedes.
I, WILLIAM BORTHWICK SMITH, of 139, Cannon Street, in the City of
London, 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 and accompanying drawing, that is to say :-
This invention relates to metal tubes or bars, and more especially to such tubes
or bars when used for the frames or other parts of bicycles, tricycles, or other
velocipedes, and it has for its object novel methods of making such frames, by which
they are very strong, light, durable, and inexpensive.
Supposing that the invention is to be applied to the frame of a bicycle or other
velocipede, which is ordinarily made of steel tube of suitable diameter and of
uniform thickness, by the present invention I make such tube so that whilst light
it is very strong, and so that the parts which receive the strain when in use are so
proportioned that the strain is properly distributed over them.
When such tube is used for instance to form the framing of a velocipede, one
(the upper) part of its section is usually under compression, whilst the other
(lower) part is in tension, and in order that the strength of the tube may be
properly proportioned, I make the (upper) part of the tube under compression of
greater sectional area than the other part. And in order further to increase the
vertical strength, I sometimes make the vertical depth of the tube greater than its
horizontal width, its section being therefore more or less elliptical.
In the accompanying drawing which is in illustration of the invention, Figure 1
shews in transverse section such an elliptical tube, the upper part of which at a (which
is in compression) being shewn of greater thickness than the lower part at 6 (which
is in tension).
The improved tubes may be formed by rolling and drawing in the usual way.
In a modified form I make the bar in the form of a flanged beam or girder, as
illustrated in Figure 2, instead of a tube, the vertical plate of the beam having a
horizontal flange at its upper and lower edges of which the upper flange may have,
though not necessarily, the greater sectional area. In order to improve the
appearance of such a beam I prefer (as shewn in side view, and in cross section, in
Figure 3) to curve the edges of the upper flange c downward and of the lower
flanged upward, so that their edges nearly or quite meet, the periphery of
the tube so formed being circular or nearly so, or elliptical or other suitable
shape, whilst great strength is obtained by means of the vertical central flange.
The upper and lower flanges c and d are preferably made thicker at the
centre where they join the vertical flange e, than at their edges which are
gradually tapered down. The longitudinal edges of the upper and lower flanges
where they meet, may be brazed or soldered together.
The tube or hollow bar of the kind described, may be made of sheet metal, such
as steel, folded into the shape required.

page_text: For instance, as illustrated in Figure 4, a strip of steel of sufficient width may be
bent into the shape shewn, having upper and lower transverse flanges.
Or, the upper and lower transverse flanges may be curved as shewn in Figure 5..
The edges of the bent strip may be made to meet in the centre of the top flange
(as shewn in Figure 6) or of the vertical central flange as shewn in Figures 5 and 7
the section of the tube shewn in Figure 7 being elliptical instead of circular. Or
the strip may be bent into the form shewn in Figure 8, and in all cases the edges
of the strip where they meet may be brazed or soldered together.
In order to join the ends of the tube or bar formed as described to other bars or
fittings, a junction piece may be used consisting of a flange or plug fitting for a
sufficient distance into the end of the tube, the flange being divided in the part
which so fits into the tube so that one part fits upon one side and the other part
upon the other side of the central plate of the tube. The outer end of the plug is
properly shaped to receive and attach any other tube or fitting which is to be fixed
to the inner tube, and it is fixed by rivets, screws or brazing.
Figure 9 illustrates another method of fitting and fixing the end of one tube
against the side of another tube.
are
"In this case the curved sides of the tube f which is to fit against the tube
cut away, leaving the central web or flange projecting, this web or flange being
passed through slots in the tube g, and the two tubes being then brazed, rivetted,,
screwed, or otherwise firmly fixed together.
I do not confine myself to any precise details of shape and proportion
of the different parts, which may be varied more or less to suit different
circumstances.
The improved tube or bar is very strong, light, and easily made, and it may
be applied to other purposes such as light girders for machinery or buildings,
where sufficient strength combined with great lightness is required, as well as to the
frames of velocipedes.
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. A metal tube, having the part which is in compression when under strain of
greater thickness than the part in tension, substantially as and for the purposes
described and illustrated in Figure 1.
2. A metal tube or bar consisting of a vertical flange, having upper and lower
horizontal flanges the outer edges of which are bent toward each other, substantially
as and for the purpose described and illustrated in Figures 3, 5, 6, and 7.
3. The method of forming metal tubes or bars of the kind described in
Claims 1 and 2, of sheets of metal bent and curved substantially in the manner and
for the purpose described, and illustrated in Figures 5, 6, 7, and 8.
4. The method of forming metal tubes or bars of a sheet of metal bent
and curved, substantially in the manner and for the purpose described, and
illustrated in Figure 8.
5. The method of forming bars having upper and lower horizontal flanges con-
nected by a vertical web or flange, of sheets of metal bent and curved, substantially
in the manner and for the purpose described and illustrated in Figure 4.
6. In combination with the tubes made as described and illustrated in
Figures 3, 5, 6, 7, and 8, the method of jointing such tubes together substantially
as described, and illustrated in Figure 9.
Dated thio 23rd day of February 1801
EDWARDS & Co.,
35, Southampton Buildings, London, Agents for the Applicant.