Improvements in the Construction of Frames for Bicycles and Similar Vehicles.
Year: 1897

page_text: Date of Application, 21st May, 1897--Accepted, 10th July, 1897
COMPLETE SPECIFICATION.
Improvements in the Construction of Frames for Bicycles and Similar
Vehicles.
I, HENRI PIEPER of 16 Rue des Bayards, Liège, Belgium, Manufacturer, do hereby
declare the nature of this invention and in what inanner the same is to be performed,
to be particularly described and ascertained in and by the following statement :--
My invention relates to the construction of frames for bicycles and similar
vehicles.
Frames for bicycles have hitherto been constructed of metal tubes secured to a
bracket and joined together at other connections by suitable lugs. At all the joints
the tubes are usually brazed or soldered strongly to the bracket and to the lugs.
Such brazing or soldering necessitates considerable heating and has the
disadvantages, first-of throwing out of shape the bracket and the head, and
second of impairing the rigidity and elasticity which the tubes have acquired at
their joining places in the operation of drawing, and especially in the final operation
of cold drawing. Brazing is also attended with the disadvantage that it forms a
sort of alloy with steel rendering that metal brittle and destroying its temper and
other valuable qualities. The tubes moreover being made very thin in order to
avoid undue weight in the machine, the brazing operation is consequently rendered
very difficult as it is liable to burn the tubes.
In my improved method of construction, I obviate the above disadvantages by
suppressing all brazing of the joints. At the ends of the tubes I form a screw
thread in such a manner as to preserve throughout the threaded part the gauge, or
thickness of the metal, of the tube. By this method no weakness is caused by the
screw-threading. The gauge of the tubes, or the thickness of the metal being often
less than one millimetre, it could not withstand screw-cutting in the ordinary way
without being actually weakened at the very places where the greatest strength is
needed..
In the joints of the bracket and of the lugs, however, where there is more
thickness of metal, I cut the screws in the usual manner.
The tubes, being screwed firmly into the lugs, form therewith a continuous part
which is capable of resisting all strains more effectually than when the parts are
joined by brazing as heretofore, and at the same time the other defects of that
method are avoided. In order to still further strengthen the joints of the thin
threaded tubes with the lugs, I insert in the threaded end of the tube a small steel
ring or liner, screwed externally to the same pitch so as to fit tightly into the tube.
Finally, to prevent the entrance of water or moisture and to obviate rust in the
screw-threaded joints, the lugs and the ends of the screwed tubes are tinned before
being joined, and after the frame has been put together the joints are heated up to
the fusion point of tin. This is done at a temperature sufficiently low not to affect
in any way the temper or rigidity of the metal.
DESCRIPTION.
On the accompanying drawings illustrating my invention,
Figure 1 is a longitudinal section of part of a tube of a bicycle frame having a
senow throad A formed on the end thereof by my improved method:

page_text: Figure 2 is a section of a round plate liner or ring B screwed to fit the internal
thread of the tube shewn on Fig. 1;
Figure 3 shews the annular plate screwed in position in the end of the tube;
Figure 4 is a section of a lug C internally threaded to receive the end of the
tube shewn on Fig. 1: this thread being cut in the metal of the lug;
Figure 5 shews one end of a tube screwed into its respective lug;
As shewn on Figure 6 (sheet 2), in constructing the frame, the lower tube D, the
down tube E, and the chain stays F are screwed into the lugs of the crank
bracket G. The saddle lug H, Figure 7 (Sheet 3) is next screwed on the down
tube E, and in this lug is inserted the top or horizontal tube I. The two lugs K and L
for the head or tube J are then screwed respectively on the lower and top
tubes, D and I. To complete the frame as shewn on Figure 8 (Sheet 4), it is only
necessary to insert the head J in the lugs K and L which are internally smooth.
The bearing-jaws M, or extremities of the chain stays F, are finally connected to
the saddle lug H as is usually done by means of two back stays with forked ends
secured by bolts to the parts H and M.
In order to obtain an accurate fitting of the head J in its lugs K and L, each of
the latter, as shewn on Figures 9 and 10 (Sheet 5), is provided internally at the
thickened part N with a circular groove P. The head J which is smooth throughout
from end to end, see Figure 11, is inserted between the two lugs K, L, and by means
of a special tool or die an annular rib R is formed in the metal of the tube to
correspond with the groove P in the lugs K, L. The ends of the tubes and the lugs
having been previously tinned, it is only necessary to heat the joints to a
temperature high enough to melt the tin whereby the several parts of the frame are
secured together. By this method a solid and compact structure capable of resisting
great strains is completed.
The screw thread in the down tube E at the position of the saddle lng H may be
formed externally in such a manner as to preserve the same internal diameter in the
tube, see Figure 12 (Sheet 6). In this case the saddle pillar S may be fitted in the
down tube E. Or the screw thread may be formed internally, see Figure 13, in
which case a length of tube T of the same internal diameter as the screw thread is
inserted within the down tube E and immediately in contact with the screw-thread,
and the saddle pillar S will be fitted therein. In this case the length of tube T
must of course be inserted in the down tube E before the two ends of the latter are
screwed having been previously tinned it can be soldered to the tube E at the
same time as the lug H.
:
Figures 14, 15 and 16 (Sheet 7) shew the method of fitting the fork on the
steering-rod.
In the steering-rod or tube V is formed a screw-thread V' (Fig. 14), and in the
fork a thread Wis cut (Fig. 15). The fork and tube being joined together fitting
is completed by screwing a steel ring or liner X into the tube V (Fig. 17).
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. In the construction of bicycle frames, the formation of the joints by means of
tubes screwed into lugs, such tubes having screw-threads formed in the metal in
such a manner that the screws ensure the same thickness of the metal, or gauge of
the tube, at every part, thereby avoiding the weakness caused by a cut screw, as
described herein and as illustrated on the accompanying drawings.
2. In the construction of bicycle frames, the use of a metallic ring screwed into
the ends of the tubes to strengthen the same at their joints, as described with
reference to accompanying drawings.
3. In the construction of bicycle frames, the method of securing together the
parts of the frame by means of a screw-thread formed at every joint, as described
herein and as illustrated on accompanying drawings.

page_text: 4. In the construction of bicycle frames, the adjustment of the head by forming
in the tube thereof by means of a special tool two circular ribs fitting into a
corresponding annular groove formed in each lug, as described.
5. In the construction of bicycle frames, the connection of the fork to the steering-
rod by means of a screw formed in the tube of the same, substantially as shewn and
described with reference to accompanying drawings.
Dated this 21st day of May 1897.
For the Applicant,
GEDGE & FEENY,
60 Queen Victoria Street, London, E.C., Chartered Patent Agents.