IMPROVEMENTS IN THE CONSTRUCTION OF VELOCIPEDES
Year: 1879

page_text: LETTERS PATENT to Josiah Turner, of the Coventry Machinists' Company,
Coventry, in the County of Warwick, and Alfred Dewey, of Holborn Viaduct,
in the City of London, Mechanic, for the Invention of "IMPROVEMENTS IN
THE CONSTRUCTION OF VELOCIPEDES,”
PROVISIONAL SPECIFICATION left by the said Josiah Turner and Alfred
Dewey at the Office of the Commissioners of Patents on the 17th July 1879.
JOSIAH TURNER, of the Coventry Machinists' Company, Coventry, in the County
of Warwick, and ALFRED DEWEY, of Holborn Viaduct, in the City of London,
Mechanic. "IMPROVEMENTS IN THE CONSTRUCTION OF VELOCIPEDES.'
This Invention relates, firstly, to an improvement in the driving mechanism of
velocipedes, whereby the effective driving power of the foot will be maintained
upon the crank shaft for a greater portion of its rotation than heretofore.
A convenient mode of attaining this end in bicycles, for example, is to fit to the
fork a pair of dead excentrics through which the crank axle passes, its centre of
motion being in advance of the center of the excentrics. To those excentrics we fit
metal straps which terminate in a slotted radial extension. In the slots of these
extension pieces we fit sliding blocks, which carry a pin that connects with the
adjacent arm of the crank axle, and forms a pivotted connection therewith.
Attached to the extremities of these radial extensions of the excentric straps are
the treadles, which are thus caused to work the crank axle through the straps.
By this arrangement of driving gear the crank axle can be propelled before onc
dead point is reached, and up to if not after its second dead point has been passed.
The second improvement relates to a mode of adjusting the "rake " of the
steering fork of bicycles, when such fork is connected to the back bone by vertical
centres. The bearing which receives the lower centre we now propose to make
adjustable horizontally, and to give it a slight traverse motion by means of a bell
crank lever or its equivalent, which may be actuated by connection with a steering
handle to which an axial motion may be imparted for the purpose of altering the
adjustment of the rake.

page_text: The last improvement in velocipedes relates to a mode of adapting a small
machine to the use of a long legged rider. To this end the steering-fork is extended
=towards_the_ground-a-sufficient_distance below the axle of the steering wheel to
permit of its prongs forming bearings for crank axles which will carry-chain-
pinions for driving the axle of the steering wheel. The crank axles mounted one
in each prong are fitted-with-treadles, and these pinions are connected by means of
chains with chain pinions-on-the-axle of the steering wheel at either side thereof.
Thus, the rider sitting upon a low seat will be enabled to work the treadles at
the full stretch of his legs, and so near-the-ground-as- to increase the safety of the
vehicle, or greatly diminish the risk of serious accident to the rider.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Josiah Turner and Alfred Dewey in the Great Seal Patent Office
on the 17th January 1880.
JOSIAH TURNER, of the Coventry Machinists' Company, Coventry, in the County
of Warwick, and ALFRED DEWEY, of Holborn Viaduct, in the City of London,
Mechanic. "IMPROVEMENTS IN THE CONSTRUCTION OF VELOCIPEDES."
This Invention relates, firstly, to an improvement in the driving mechanism of
velocipedes, whereby the effective driving power of the feet upon the crank shaft
will be increased at certain parts of the rotation of the crank shaft.
A convenient mode of attaining this end in bicycles, for example, is to fit to the
fork a pair of dead excentrics through which the crank axle passes. To these
excentrics we fit metal straps, which terminate in a radial extension for receiving a
pin that couples it with the slotted adjacent arm of the crank axle. These pins
serve to carry the treadles, which as the crank axle is rotated move radially
towards and from their centre of motion, and thus afford a varying leverage for the
working of the driving wheel.
In Sheet I. of the accompanying Drawings Fig. 1 shews in sectional plan view
so much of a bicycle as will serve to explain the first head of this Invention, and
Fig. 2 is a side view of the portion of the bicycle shewn in Fig. 1.
In these views A is the driving axle, and A¹ its crank arms; B shews a portion
of the driving wheel, and C a portion of the steering fork in which are the
bearings for the crank axle.
D, D, is a pair of dead excentrics attached to the outer sides of the fork, and
fitted to these excentrics are metal straps with extension pieces E, to which are
secured adjustably the treadle pins F. These pins serve also to couple the parts E ·
with the crank arms A'.
Gare the treadles swivelling on the connecting pins F.
The positions of the two excentrics it will be seen are such that a line drawn
through their largest radius will be at right angles or thereabouts with a central
line drawn through the fork, and in advance of the fork.
The crank arms A¹ being slotted longitudinally to receive their connecting
pins F, these pins will as the crank axle is rotated slide to-and-fro in the slots,
being firmly secured (adjustably) by clamping nuts to the excentric strap pieces E.
As the connecting treadle pins F are acted on by the feet of the rider, the
excentric strap pieces will be caused to travel around their excentrics, and they
will thus present an ever varying length of leverage to the feet of the rider.
This leverage it will be seen increases as the crank arrives at the best position
to receive the pressure of the rider's foot, and by this means a very efficient
driving action will be secured.
In order to diminish the friction of the straps on the excentrics, the well known
contrivance of antifriction balls may be employed (as shewn at Fig. 2) or in lieu of
these antifriction rollers mounted in recesses formed in the periphery of the
excentrics, as shewn in the detached view Fig. 3, may be employed.
This Invention relates, secondly, to a mode of adjusting the "rake" of the
steering fork of bicycles, when such fork is connected to the backbone by vertical
centres. For this purpose we now propose to make the centres adjustable in the
vertical plane of the backbone, giving the same a slight rocking motion by means
of a bell-crank lever or its equivalent.
The equivalent which we employ by preference is a loose cam, by turning which
against a fixed bearing surface the adjustment of the inclination of the fork is
effected.
In Sheet II. of the Drawings Fig. 4 is a plan view of the steering head of a
bicycle shewing our improvement applied, and Fig. 5 is a side elevation of the
neute

page_text: A is the forward extremity of the backbone to which is jointed at B a bracket
piece C, for connecting with the fork D of the driving wheel.
The stem of this fork-is-recessed,-as-shewn at D₁, to receive the vertical rounded
edge of the hinged piece C. Through the upper end of the stem a centre pin E
-is-passed to enter a socket.formed to receive it in the centre of the rounded part
=-of-the-bracket C.
=
-The-lower end of this portion of the bracket is fitted with a similar centre [pin E',
which enters a cup socket let into the lower portion of the stem of the fork D. By
this arrangement of the vertical-centres suitable provision-is-made-for-holding the
lubricating oil.
Mounted loosely on the stem of the fork above the level of the bracket piece C
and immediately below the steering handles F is a cam G, with a radial extension
for receiving a handle G' for working it. On a level with this cam the front end
of the backbone is shaped to receive an antifriction bowle G2 against which the
cam bears, the contact of the bowle and cam being maintained by the weight of the
rider.
In the Drawing, the cam is shewn in the position which ensures the verticality
of the fork and when in this position a shoulder of the hinged bracket piece Č
butts against a shoulder on the forward end of the backbone. When however tho
fork is required to be canted backwards to the position indicated by the dotted line
Fig. 5, the handle G¹ is moved from its drawn position Fig. 4 to the dotted position,
by which movement the smallest acting radius of the cam will be presented to the
bowle G².
This shifting of the handle G¹ will therefore give the fork D its greatest rake,
and will thereby ensure safety to the rider in descending a bill. The amount of
"rake" will of course be determined by the position of the handle G', which may
be set at any point between the two extreme positions shewn in the Drawing.
Having now set forth the nature of our Invention of "Improvements in the
Construction of Velocipedes," and explained the manner of carrying the same into
effect, we wish it to be understood that under the above in part recited Letters
Patent we claim :-
First. The arrangement of mechanism described with reference to Sheet I. of the
Drawings, whereby an extended leverage for receiving the propelling action of the
rider is provided at the points of rotation of the crank shaft, where it may be most
efficiently employed.
Secondly. The arrangement described with reference to Shect II. of the
Drawings for adjusting the "rake" of the front fork of bicycles.
In witness whereof, I, the said Alfred Dewey, have hereunto set my hand and
seal, the Sixteenth day of January, in the year of our Lord One thousand
eight hundred and eighty.