IMPROVEMENTS IN AND RELATING TO VELOCIPEDES
Year: 1880

page_text: LETTERS PATENT to Thomas Pritchard, the younger, of Coventry, in the
County of Warwick, for an Invention of "IMPROVEMENTS IN AND RELATING
TO VELOCIPEDES.”
PROVISIONAL SPECIFICATION left by the said Thomas Pritchard, jr., at the
Office of the Commissioners of Patents on the 11th November 1880.
THOMAS PRITCHARD, the younger, of Coventry, in the County of Warwick.
"IMPROVEMENTS IN AND RELATING TO VELOCIPEDES."
This Invention has for its objects:
=
Firstly. Improved means of transmitting motion to the wheels of that class of
velocipedes in which the driving wheels are allowed independent motions in
turning or performing a curvilinear path, and consists in attaching to one side of
the hub of the driving wheel an internally toothed wheel, the whole running loose
on the main shaft. On this shaft, concentrically with the internally toothed wheel,
I fix or key another toothed wheel. Intermediately between and gearing into both
these wheels is a smaller wheel or pinion running loose on a stud or pin carried by
the chain wheel actuated from the treadles.
For protection from dust, damage, etc., the working parts may be enclosed in a
box or case.
It will be seen that when the machine is running in a straight path the main
wheels receive direct motion from the chain wheel actuating the pinion which
operates the main gears, but on directing the machine in a curvilinear path the
pinion revolving on its axis can also be carried round the main gears in either
direction as required by the rider, thereby allowing each wheel to move indepen-
dently of the other.
Secondly. A novel method of obtaining different speeds, as may be required in
ascending hills. For this purpose I employ differential chain gearing, each
arrangement of gearing for transmitting different speeds to the main wheels being
put in and out of action by a clutch operated by a lever or equivalent
mechanism.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Thomas Pritchard, jr., in the Great Seal Patent Office on the
11th May 1881.
THOMAS PRITCHARD, the younger, of Coventry, in the County of Warwick.
"IMPROVEMENTS IN AND RELATING TO VELOCIPEDES,"
This Invention has for its object improved means of transmitting motion to the
wheels of that class of velocipedes in which the driving wheels are allowed
independent motions in turning or performing a curvilinear path.
To elucidate my Invention I have annexed a Sheet of Drawings, to which I now
refer.
velocipede.
Fig. 2 shows a view of the chain wheel on axle and the pinion which gears into
the two large toothed wheels in Figure 1. The chain wheel is so constructed as to
form a dust-proof covering for the whole gearing motion.
Fig. 3 shows a part front viow (partly in section) of a velocipedo with my
gearing affixed.
To the hub of the large or road wheel A is secured the internally toothed
wheel B.
This wheel A, carrying the wheel B, runs loose on the axle C, as shown in dotted
lines in Figure 3.
To the axle C is fixed the spur wheel D.
A chain wheel (Figure 2) runs loose on the axle C, and to which rotary motion
is transmitted through an endless chain from the chain wheel on the crank shaft E,
or these wheels might be otherwise geared together.
F is the small pinion, which revolves on its own axis, and takes its bearing
horizontally in the chain wheel (Figure 2), and which gears into the internally
toothed wheel B and also into the spur wheel D. The other large driving or road
wheel G is secured upon the axle C.
The rotary motion (as communicated from the chain wheel on the crank shaft),
being imparted whenever there is exactly the same amount of resistance offered by
the two large or road wheels A and G (as when travelling in a straight path), the
pinion F remains stationary on its axis, and transmits an amount of driving power
equally to each of tho road wheels A and G; but whenever the pressure upon these
two wheels becomes unequal, for example, as when turning a corner or pursuing a
curvilinear path, the pinion F (being loose upon its axis) will yield under the
unequal pressure and revolve, thus allowing either of the large or road wheels to
go faster or slower than or even turn in a contrary direction to the other.
Immediately the pressure upon both wheels becomes equal the pinion F will of
necessity become stationary and takes or carries round both wheels as before.
I arrange the teeth of the wheel B to project laterally, as shown in Figuro 3,
and a projecting annular ring or flange I formed on tho chain wheel overlaps this
and thus acts as a box to keep out dirt or grit. It is obvious that the details of
my Invention may be varied without departure from the principlo thereof.
Having now described my Invention, and the best mode known to me of
performing the same, I would have it understood that what I claim as novel and
original is,―
Firstly. In combination with the spur pinion F, carried by the wheel operating

page_text: the gearing, the internally toothed wheel secured to one main wheel, and the spur
wheel D driving the other main wheel for the purposes described.
Secondly. The general arrangement of apparatus, substantially as and for the
purposes described.
In witness whereof, I, the said Thomas Pritchard, the younger, have hereunto
set my hand and seal, this Ninth day of May, in the year of our Lord
1881.
THOMAS PRITCHARD, THE YOUNGER. (LS)