IMPROVEMENTS IN THE MANUFACTURE OF VELOCIPEDES
Year: 1877

page_text: PROVISIONAL SPECIFICATION left by Josiah Turner at the Office of the
Commissioners of Patents on the 20th December 1877.
JOSIAH TURNER, of the Coventry Machinists' Company, Coventry, in the County
of Warwick. IMPROVEMENTS IN THE MANUFACTURE OF VELOCIPEDES."
"
The chief object of this Invention is to construct bicycles which will possess
strength and rigidity with a diminution of weight. A reduction of weight in these
machines has been effected by making certain of the parts hollow, such as the
back bone and the forks, and by the use of steel in place of wrought iron.
. I now propose to form the tubular parts of these machines of such a section as
will ensure great power of resistance to both vertical and lateral strains. Thus
instead of the circular section given to the backbone, I make the steel tube three
sided, prefering the form of an equilateral triangle in cross section, and this tube
I taper from the front to the rear end.
The way in which I propose to construct this novel form of backbone is as
follows:-I provide a set of shaping rollers, say, three pairs suitably graduated in
form to reduce the tube to be operated upon by graduated steps for the desired
sectional form. These pairs of rolls will each consist of a V roll and a flat roll, the
flat roll being slightly recessed to provide shoulders for lining the lateral spread of
the metal. Through this set of shaping rolls I pass a clylindrical seamless steel tube
heated to a red heat, and I thus reduce the tube from end to end to the desired
sectional figure, viz., an equilateral triangle with rounded angles.
In order to taper this tube or lengths thereof to form a backbone for a bicycle,
I provide a pair of rolls of such size that their peripherical measurement will be
equal to the greatest length of backbone required, and in these rolls I cut one or
more tapering grooves of a triangular form corresponding to the taper desired for the
backbone. Through these rolls I pass the steel tube which has been reduced to a
uniform triangular section, and I thereby draw down the tube to the desired taper.
It only then remains to give the tube the curve desired for the backbone, which
may be done in any ordinary manner.
The mode of fitting the parts to this backbone will be similar to that adopted in
fitting backbones to other sections.

page_text: I also propose as an improvement in the forks of bicycles to make the prongs of a
hollow triangular section, and to fit the head and socket bearings thereto by
brazing.
In order further to lighten the bicycle I construct the spokes of the wheels of
wire of just sufficient gauge to ensure the obtaining of the desired strength, and
instead of reducing the strength of this wire by screwing the end which enters the
hub of the wheel, I fit a tubular screw to the end of the wire and tap the hub to
receive this increased diameter of screw.
In order to secure this hollow screw to a wire spoke, I submit the wire to the
action of dies, which will knock up a head on the end of the wire and form fins on
the under side thereof.
The end of the hollow screw which is to fit against this head, I nick to receive
the fins, and then by brazing or soldering I secure the screw permanently to the
wire; to the other end of the screw I fit a nut which is made with a conical
extension to embrace the wire spoke. When the spoke is screwed into the hub, this
nut is screwed down to the hub and forms a lock nut to the spoke. It serves also
by reason of its conical extensions as a lateral support for the spoke, and hides any
irregularities due to the different distances at which the screws (when the spokes ar
brought to tension) will stand out from the hub.
This improvement in the wheels is applicable to velocipedes generally.
As an improvement in three wheeled velocipedes I propose to arrange the driving
gear so as to reduce at pleasure the speed of the running wheels when ascending
inclines, and thereby to enable the rider to ascend hills with less exertion than has
been hitherto required. To this end I mount the driving wheels on a straight shaft
which runs in bearings in the carriage frame, and this shaft I connect by gearing
with the crank or treadle shaft which is mounted on centres.
To the crank shaft are keyed two spur wheels of different diameters, and on the
straight shaft are mounted loosely two spur wheels gearing into these. A clutch
fitted to the straight shaft lies between the loose spur wheels, and serves to lock
either wheel as desired to its shaft.
When the larger wheel on the crank shaft is the driver, the speed of the two
shafts will be the same, but when the smaller wheel is made the driver, the speed of
rotation of the straight shaft and consequently of the travelling wheels will be pro-
portionately diminished.
When both of the loose spur wheels are freed from the clutch, the velocipede will
run down hill without any movement of the feet on the pedals.