An Improved Method of Joining Metal Tubes to Lugs and other Fittings for Bicycle Frames and other Purposes.
Year: 1897

page_text: PROVISIONAL SPECIFICATION.
An Improved Method of Joining Metal Tubes to Lugs and other
Fittings for Bicycle Frames and other Purposes.
WILLIAM HENRY BOYD, 327, Green Lanes, Small Heath, Birmingham, Manu-
facturer, do hereby declare the nature of this invention to be as follows:-
I make lugs with corrugation inside either vertical or spiral, and I make ends
of the tubes with similar corrugations. I slit the end of the tube in several places
to the depth of about one eighth of an inch, and I also make a slight indenta-
tion all round the outside of the tube where the corrugation ends. I then make
lug red hot and insert tube cold. I make the tube to fit very tightly. When
the lug is cold the contraction causes the joint to be perfect and immovable. I.
afterwards insert a tool which has a bulb to fit top of tube where the slits are,
and by pressure on this tool the slit portions of tube are widened out and by pres-
sure with a tool at end of rim of lug, the rim is forced into the indentation at
bottom of the corrugations on tube, and the two make it quite impossible to move
the tube either up or down in the lug or in fact to move it in any way.
I can also use plain lugs and tubes with an expanding tool to be used inside
tube to produce the joint, but I prefer the corrugated.
An Improved Method of Joining Metal Tubes to Lugs and other
Fittings for Bicycle Frames and other Purposes.
I, WILLIAM HENRY BOYD, of 327, Green Lanes, Smallheath, Birmingham, in
the County of Warwick, Commission Agent, 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:-
I make lugs to taper inside nearly the whole way through from end where tube
enters lug. Where taper ceases, I make a recess or another short taper in lug
in opposite direction to the first taper.
I make one or more corrugations inside lugs from mouth to the end of first taper
or I can leave them plain inside as I think fit.
I then taper the ends of tubes to exactly fit the inside of lugs, these tapered
tubes to be either corrugated or plain according to the lugs made use of.
I slit the ends of these tubes to the depth of an eighth of an inch or more as
may be necessary.

page_text: Instead of tapered lugs and tubes I can use parallel ones, either plain or corru-
gated, for joints but I prefer to use them tapered and corrugated.
I further make a circular corrugation or collar in tubes at place from which
taper starts in same.
The accompanying drawings and descriptions will more fully explain my in-
vention and how it may be put into practice.
Figure I upper part the lug A is tapered inwardly from mouth to .E. From E
it is tapered in an opposite direction and marked F. B is the corrugated
tapered end of Tube to fit lug A. D is a circular corrugation or collar on the
tubes.
The lug is heated and the Tube B driven in cold as far as D.
The slit end C of Tube is then expanded against the taper F of lug A.
The mouth rim of the lug A is then forced into the corrugation D of Tube B In
cooling the lug shrinks on to the Tube and forms an immoveable joint.
In bottom part a plain tapered joint is shewn G is a plain tube with tapered
end The slit ends of the tube C are expanded at F the corrugation or collar L
is made bevelled and so also is the rim of mouth of lug The lug is heated
and shrunk on as above the rim of mouth pressed into corrugation and in con-
sequence of its bevelled shape a firm joint, which cannot be turned round, is
made.
H and K is a line perpendicular to the axis of the tube and lug, while the
plane of the groove L is oblique to such axis.
Figures 2 and 3 shew joints made with parallel lug and tube. A is outside lug
as it appears in finished joint. B is a parallel tube with corrugation at D. where
mouth of Tug is pressed in C are slits at end of tube which is expanded in end
cf lug after it has been heated and shrunk on tube.
Figure 4 is a section of a lug and a tube with 6 corrugations inserted in it.
Figure 5 is a tube with a tapered end.
Figure 6 is a section of a fork tube with corrugations.
Figure 7 is a Bicycle Frame complete as it appears when finished. The letters
A shew joints.
Figure 8 shews two tubes joined together by my method. B shews end of tube
reduced with a circular corrugation at D. C shews slit end of Tube. The
female tube is heated and the male tube driven in cold. The end of the female
tube is forced into corrugation at D and a perfectly water, gas or air proof joint
is formed.
Figures 9 and 10 shew a tool used to expand slit ends of tubes in certain lugs.
M shews the bulb. These tools are made of various sizes and are used by bulb
being forced down in slit ends of tubes until they are properly expanded."
Tubes and sockets for other purposes I put together in the same manner.
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:-
A method of joining metal tubes to lugs and other fittings for Bicycle Frames
and other purposes, without Brazing, which will make absolutely immoveable
and sound joints without any loss of strength whatever.
W. H. BOYD.
Birmingham.