Improvements in Gas or other Motive Power Engines.
Year: 1890

page_text: Date of Application, 19th June, 1890
Complete Specification Left, 19th Mar., 1891-Accepted, 25th Apr., 1891 ·
PROVISIONAL SPECIFICATION.
Improvements in Gas or other Motive Power Engines.
I, GEORGE ROBSON, of 13, Shakespeare Terrace, Sunderland, in the County of
Durham, Engineer and Iron Merchant, do hereby declare the nature of this inven-
tion to be as follows:-
-
My invention relates to improvements in gas or other motive power engines.
The novelty of my invention consists substantially of constructing the cylinder of
the engine so as to contain two pistons of equal diameters but having unequal
strokes and working in opposite directions but actuating the same crank shaft.
One piston actuating a crank or cranks from what may for the purpose of this
description be called the front end of the cylinder and the other piston actuating a
crank or cranks through the back end of the cylinder.
The cranks of the two pistons may be set at any suitable angle to each other.
By these arrangements and selecting a suitable point for the explosion of the gases
between the pistons, I can get the crank or cranks at an angle to the line of
travel of the pistons at the time of the explosion without any unnecessary cylinder.
space being used.
I would have it clearly understood that I do not limit myself to any particular
method of introducing the gases into the cylinder nor do I confine myself to
exerting power on one side of the pistons only nor of the method of compressing
the gases nor to any particular arrangement of design as to the carrying out of my
invention.
Dated this 16th dov of Lu 1800
GEORGE ROBSON.
COMPLETE SPECIFICATION.
Improvements in Gas or other Motive Power Engines.
I, GEORGE ROBSON, of 13, Shakespeare Terrace, Sunderland, in the County of
Durham, Engineer and Iron Merchant, do hereby declare the nature of this inven-
tion, 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 improvements in gas or other motor power engines.
The novelty of my invention consists substantially of constructing the cylinder
of the engine so as to contain two pistons of equal diameter but having unequal
strokes and working in opposite directions but actuating the same crank shaft.
I will describe my invention with reference to the accompanying drawings in
which
Figure 1 shows a longitudinal section of a single cylindered engine with double
pistons actuating the same crank shaft.
Figure 2 is a cross-section through the centre of the cylinder showing
valves.
Figure 3 shows in section an arrangement of gas, igniting and admission valves
and method of operating the ignition.
Figure 4 is a cross-section through the guide bars of the rear piston.
Like letters indicate like parts throughout the following description.
a is a motor cylinder with water jacket a' mounted on a bed plate a' in the
isual way. a, a, are pistons of which as operates through connecting rod a
crank a on crankshaft a while a operates through two lateral connecting
rods a cranks a' of crankshaft a'. Thus a may have a 7-inch stroke and a* a

page_text: 5-inch stroke making a combined stroke of 12 inches, both pistons operating one
shaft. The cranks of the two pistons may be set at any suitable angle to each
other. In Fig. 1 they are shown set at an angle of 215° but this angle may be
reduced or the cranks may be set at an angle of 180° to one another. An effect of
having a double-pistoned engine with one cylinder as described enables any single
cylindered engine to have its cranks so set as that one thereof may always be off
the dead centre.
bis the admission port to the cylinder and the exhaust. 2 is the admission
valve for gas and air or air alone, 3 the gas admission valve and the valve for
timing the ignitions. All these valves may be arranged and worked in any suitable
manner or as indicated in the drawing wherein the gas and admission valves are
operated by levers 7 worked from cams on side shaft s, the timing valve being
operated by one of the side connecting rods a² of the rear-piston. In this arrange-
ment, a small roller fitted on the side of the rod as is caused to strike a projection
on the lever mounted as shown which thus operates the timing valve situated
between the admission valve and the ignition tube. Through a boss in an extension
of the rear piston the gudgeon y passes and in an extension of the cylinder for this
purpose, the blocks work in lateral guides cast on the cylinder extension as
shown in Fig. 4. The gudgeon ends take the ends of the lateral connecting
rods.
7"
When an explosive mixture is admitted to the cylinder-and exploded, the pistons
are driven outwards from each other; the momentum of the engine returning the
pistons drives out the products of combustion through the exhaust port and carries
the pistons outwards again when a fresh explosive charge may be drawn in and
compressed between the pistons in their return stroke.
On ignition the motions are repeated.
Steadiness, regularity and a high speed may thus be obtained.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is
1. A double-pistoned single-cylindered engine wherein the pistons travel unequal
distances in opposite directions and actuate one crank shaft substantially as herein
set forth.
2. A single-cylindered engine containing two pistons having unequal strokes and
working in opposite directions whereof the rearmost piston is connected by two
lateral connecting rods and the foremost piston by one medial rod to the same
crank shaft, the cranks of which may be set at any suitable angle to each
other the several parts being arranged and operating substantially as herein set
forth.
A. CRAWHALL CHAPMAN,
3, St. Nicholas Buildings, Newcastle-on-Tyne, Patent Agent for Applicant.