Year: 1888

page_text: Date of Application, 20th July, 1888
Complete Specification Left, 20th Apr., 1889
Complete Specification Accepted, 25th May, 1889
I HENRY PLATT HALL of Gorse Bank Werneth Oldham in the County of Lancaster
Engineer, do hereby declare the nature of this Invention to be as follows:-
My invention relates to improvements in the ignition mechanism of motor engines
operated by the explosion of mixtures of gas or other fluid and air and more
particularly to those engines in which the explosive mixture is fired by means of a
heated tube.
I find that when at starting the engine is turning slowly round the valve admitting
the explosive mixture in the cylinder to the igniting tube should open when the crank
is on the dead centre or very slightly before but when the engine is running at or
about full speed the valve requires to be opened considerably sooner in order to ignite
the mixture at the commencement of the outward stroke of the piston.
My improvement consists then in applying a suitable mechanical device in such a
way that it will control the time of opening of the ignition valve and insure the ignition
of the explosive charge at the proper time as above specified.
A suitable arrangement for the purpose but which is described only by way of
example would be to use two cams placed close together one of which would be set
a little in advance of the other. A bowl attached to the lever or other mechanism for
In starting
working the firing valve would be actuated by one or other of these cams.
the bowl would be set so as to be acted on by the less advanced cam and when the
engine had attained its normal speed the bowl would be moved so as to be acted upon
by the more advanced cam; the change of position of the bowl in this case would
easily be effected by hand.
Instead of the above method of using two cams a double cam might be used, i.e. a
cam with two projections placed in different planes that one or the other projection
might act upon the bowl as required.
A further modification would be to have the position of the bowl controlled by
the governor; in that case it is preferable to use a broad cam the projection on
which is set in an oblique direction to the axis of the stud or shaft on which the cam

page_text: In starting the less advanced portion of the projection would be used to operate the
valve and as the engine attained its normal speed the bowl would be gradually moved
across the cam by a lever acted on by the governor the more advanced portions of the
cam being thus made to operate the firing valve.
Another arrangement would be to move the cam laterally on the shaft this can be
done either by hand or by the governor the bore of the cam having a helical groove
in which a key or projection on the shaft fits such lateral movement of the cam
would by means of the above mentioned helical groove and key cause the cam to
make a small rotary movement on the shaft and make the projection act on the firing
arrangements by opening the firing valve proportionately sooner as the engine attains
its normal speed.
By these means the explosive mixture in the cylinder would be always ignited at
approximately the same position of the piston and all risk of back ignition on starting
would be avoided.

page_text: Improvements in Motor Engines Operated by the Combustion
of Explosive Mixtures of Fluids.
I, HENRY PLATT HALL, of Gorse Bank, Werneth, Oldham, in the County of
Lancaster, 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 improvements in the ignition mechanism of motor engines
operated by the explosion of mixtures of gas or other fluid and air and more
particularly to those engines in which the explosive mixture is fired by means of a
heated tube.
I find that when, at starting, the engine is turning slowly round the valve admitting
the explosive mixture in the cylinder to the igniting tube should open when the
crank is on the dead centre or very slightly before; but when the engine is running
at or about full speed the valve requires to be opened considerably sooner in order to
ignite the mixture at the commencement of the outward stroke of the piston.
My improvement consists in applying a suitable mechanical device in such a way
that it will control the time of opening the ignition valve and insure the ignition of
the explosive charge at the proper time as above specified.
In
A suitable arrangement for the purpose, but which is described only by way of
example, would be to use two cams placed close together one of which would be set
a little in advance of the other. A bowl attached to the lever or other mechanism
for working the firing valve would be actuated by one or other of these cams.
starting, the bowl would be set so as to be acted on by the less advanced cam, and
when the engine had attained its normal speed, the bowl would be moved so as to be
acted upon by the more advanced cam; the change of position of the bowl in this case
would easily be effected by hand.
Instead of the above method of using two cams a double cam might be used, i.e. a
cam with two projections placed in different planes that one or the other projection
might act upon the bowl as required.
A further modification would be to have the position of the bowl controlled by the
governor; in that case it is preferable to use a broad cam, the projection on which
is set in an oblique direction to the axis of the stud or shaft on which the cam
rotates.
In starting, the less advanced portion of the projection would be used to operate the
valve and as the engine attained its normal speed the bowl would be gradually moved
across the cam by a lever acted on by the governor, the more advanced portions of the
cam being thus made to operate the firing valve.
Another arrangement would be to move the cam laterally on the shaft; this can
be done either by hand or by the governor the bore of the cam having a helical
groove in which a key or projection on the shaft fits, such lateral movement of the

page_text: cam, would, by means of the above mentioned helical groove and key cause the cam
to make a small rotary movement on the shaft, and make the projection act on the
firing arrangements by opening the firing valve proportionately sooner as the engine
attains its normal speed.
And in order that my invention may be fully understood and readily carried into
effect I will describe the accompanying Sheet of Drawings reference being had to the
figures and letters marked thereon.
Figures 1, 2, and 3 are three views illustrating an arrangement of two cams for
controlling the time of opening of the ignition valve according to my invention.
Figs. 4, 5, and 6 illustrate another arrangement with a broad cam and a bowl the
position of the former being controlled automatically by the governor.
Figs. 1, 8, and 9 illustrate a third arrangement in which also the position of the
cam on the shaft is adjusted by the governor.
Similar letters refer to similar parts throu hout the several views.
Referring first to the arrangement illustrated by Figs. 1, 2, and 3 in which a
designates the rotating cam shaft, bb two cams mounted thereon side by side
preferably cast together in one piece, 6 being the less advanced or starting can and
the more advanced or full speed cam; e designates the bowl and d the lever which
is fulcrumed at d¹ and operates the spindle e see Fig. 7 of the ignition or firing valve
not shown. F
At starting the bowl c would lie in contact with the cam b being held in place by
a pin fas shown but when the engine bas attained its normal or desired speed the pin f
is taken out the bowl c moved by hand into its othor position over the full speed cam b¹
and the pin freplaced.
In place of securing the cams on the shaft a I may mount them loose on the
shaft so that their relative axial positions to one another can be readily changed. To
effect this I make a fast collar on the shaft against which one of the cams lies and the
side or face of the second cam lies in contact with the first one the cams being held in
their positions by a friction nut which screws on the shaft and bears against the second
cam by slackening the nut either or both of the cams can be moved ax'a'ly on the
shaft a and be again secured by turning and tightening up the nut.
In Figs. 4, 5, and 6 there is a broad cam 62 the projection on which is set at an
oblique angle to the axis of the shaft. The cam 2 is mounted loosely on a feather key
on the shaft a and has a groove b³ turned in it which is clipped by the forked end of
a lever g connected to and operated by the governor not shown.
As the engine increases in speed the cam is traversed by the governor through
the forked lever g on to the more advanced portion of the cam b³.
It is obvious that instead of mounting the cam so as to be moved by the governor
the same effect could be attained by securing the cam on its shaft and connecting the
governor to the bowl so as to move it along the cam.
In Figs. 7, 8, and 9 the bore of the cam
has a helical groove into which fits
a projection a¹ on the shaft a, the cam being mounted loosely on the shaft as in the
preceeding arrangements. The cam has a groove turned in it which is clipped
by the forked end of the governor lever g as aforesaid. Then when the cam is
traversed along the shaft a by the action of the governor it is also moved axially on
the shaft by means of the helical groove and the projection a¹ so causing the
projecting portion of the cam to be more or less advanced according to the speed of
the engine.
By these means the explosive mixture in the cylinder would be always ignited
at approximately the same position of the piston whether the engine be running
fast or slow and all risk of back ignition on starting would be avoided.
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. In motor engines operated by the combustion of explosive fluid mixtures
ignited by an incandescent tube I claim controlling the time of opening of the

page_text: ignition or firing valve by means of a suitable mechanical device whereby the ignition
of the explosive charge at the proper moment is insured for the purposes and in the
manner substantially as specified.
2. The several combinations and arrangements of parts constituting suitable
mechanical devices for effecting the object of my improvements substantially as herein
described with reference to the accompanying Drawings.
Dated this 18th day of Anvil 1880
H. B. BARLOW,
17, St. Ann's Square, Manchester,
Agent for Applicant.