Improvements in Pransmitting notary motion.
Year: 1897

page_text: Date of Application, 16th Mar., 1897
Complete Specification Left, 15th Dec., 1897-Accepted, 5th Feb., 1898
I, DAVID DUNCAN Esson, of 25, Stone Street, Faversham, in the County of Kent,
Engineer, do hereby declare the nature of this invention to be as follows:
:―
My invention relates to means for transmitting rotary motion from one shaft to
another by means of fluid pressure.
According to my invention I use an enclosed body of water or other liquid which
is caused to circulate, through suitable pipes, by means of a piston on the driving
shaft and to act upon a piston on the driven shaft.
In carrying out my invention I find it advantageous to make use of two rotary
piston wheels each of which is mounted excentrically in a chamber or cylinder so
that the surface of the piston wheel will joint against the surface of the cylinder at
the point of shortest diameter.
The two chambers are connected together by two circulating pipes one being on
each side of the joint line between the piston wheel and cylinder.
Each piston wheel carries say two sliding pistons which always move in contact
with the surface of the cylinder in such a manner that when one piston is pressed
into the piston wheel the other is fully extended, whereby the exposed areas of the
two pistons are different.
With this arrangement as one piston is rotated the fluid in front of the piston
which is shortening is caused to act behind the piston in the other cylinder which
is lengthening whilst the fluid in front of this piston is simply being returned to
the cylinder of the driving piston.
When my invention is applied for transmitting motion from the crank axle of a
bicycle to the driving wheel the bars of the frame may be advantageously used as
the circulating pipes.
Improvements in Pransmitting notary motion.
I, DAVID DUNCAN ESSON, of 25, Stone Street, Faversham, in the County of Kent,
Engineer, 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:-
My invention relates to means for transmitting rotary motion from one shaft
to another by means of fluid pressure.
According to my invention I use an enclosed body of water or other fluid which
is caused to circulate, through suitable pipes, by means of a piston on the driving
shaft and to act upon a piston on the driven shaft.

page_text: In carrying out my invention I find it advantageous to make use of two rotary
piston wheels each of which is mounted so that the surface of the piston wheel
will joint against the surface of the cylinder at a point.
The two chambers are connected together by two circulating pipes one being
on each side of the joint line between the piston wheel and cylinder.
Each piston wheel carries say two sliding pistons which always move in contact
with the surface of the cylinder in such a manner that when one piston is pressed
into the piston wheel the other is fully extended.
To enable my invention to be fully understood I will describe the same by
reference to the accompanying drawing, in which :-
Figure 1 is a sectional elevation of apparatus for carrying out my invention;
and,
Figure 2 is a sectional plan of the same.
a indicates say the driving shaft and 6 the shaft to be driven. C, d are rotary
piston wheels mounted on the shafts a and b respectively, each of the said
piston wheels, as shewn in the drawing, being provided with two sliding pistons e, e¹
which at their outer ends are of the same width as the piston wheel and which are
normally pressed outwards by springs f,f. g,h are the casings or chambers in
which the said piston wheels work, the said chambers being of such shape and
having the shafts a, b passing through them in such a manner that the piston
wheels will make contact with the walls of the said chambers on the partitions i
between two ports or openings j, k formed in each chamber. 7, are the circulating
pipes each of which extends from the port j of one chamber to the port of the
other chamber.
It is to be understood that the piston wheel and pistons in each cylinder are
arranged in such a manner that they move between the two sides of the same,
suitable packing being employed, if necessary, in order to make good joints for
preventing leakage around the wheel and pistons.
With this arrangement when the apparatus is filled with water or other fluid and
rotary motion is imparted to the shaft a so as to move the piston wheel c in the
direction of the arrow in Figure 1, fluid will be forced from the piston chamber g
through the port. j of the said chamber to the port k of the chamber h and act upon
one of the pistons of the piston wheel d to cause the latter to rotate in the direction
of the arrow 2, Figure 1, the other piston of the piston wheel d forcing the water in
front of it through the port j back to the port of the piston chamber g.
If the sectional areas of the water spaces in connection with the two piston wheels
are the same and the said piston wheels are of the same diameter, the rotary motion
transmitted from one piston to the other will be uniform. If, however, the driven
piston wheel is of smaller diameter than the driving piston wheel, then
the driven piston wheel d will rotate faster, the relative speeds of the driving
and driven shafts being in proportion to the relative diameters of their respective
piston wheels.
m is a screw plug which normally closes an aperture through which fluid can
be introduced into the apparatus, and n, n are stuffing-boxes upon the piston
chambers through which the shafts a and b pass and which serve for preventing
leakage around the said shafts.
It will be obvious that with this arrangement rotary motion can be transmitted
from one shaft to another without regard to the relative positions of the said
shafts.
My invention is very advantageously applied for transmitting motion from the
crank axle of a bicycle to the driving wheel in which case the tubes of the frame
may advantageously be arranged to serve as the circulating pipes.
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 apparatus for transmitting rotary motion from one shaft to another, by

page_text: means of fluid pressure, the combination of two rotary piston wheels fixed upon
the driving and driven shaft respectively casings enclosing the said piston wheels
and each provided with inlet and outlet ports, and circulating pipes connecting
the inlet port of one chamber with the outlet port of the other chamber, substantially
as described.
2. In apparatus for transmitting rotary motion by means of fluid pressure from
one shaft to another, the combination of a rotary piston wheel mounted on the
driving shaft and enclosed in a casing, a piston wheel mounted on the
driven shaft and also enclosed in a casing and two circulating pipes connecting the
two casings each of the said piston wheels being in contact with its respective
casing on a partition between the ports or apertures to which the circulating pipes
are connected and being provided with sliding pistons substantially as described.
Dated this 15th day of December 1897.
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.