Improvements in Engine Counters or Revolution Indicators.
Year: 1899

page_text: PRUVIDIONAL DEAL
Improvements in Engine Counters or Revolution Indicators.
I, JAMES SCOTT MONRO, 44, Constitution Street, Leith, in the County of Mid-
lothian, North Britain, Engineer, do hereby declare the nature of this invention
to be as follows:-
This invention relates improvements in engine counters or revolution indicators.
The improvements consist firstly, in the application of a system of jointed
levers, commonly known as the "toggle motion" in combination with an ordi-
nary ratchet motion, for driving the first or units wheel.
The advantages of this combination are that notwithstanding a large excess
of motion imparted to the "toggle motion" from its connection to the moving
parts of a steam engine or other machine, the ratchet pawl and wheel cannot
advance beyond the position attained when the toggle motion reaches or passes
the straight line, thus securing that the units wheel shall come gradually to rest
in the exact position required. An excess of motion can be imparted to the levers
when the connection with the engine is first made; without affecting the smooth
working of the counter, and thus allowance is made for lost motion through wear-
ing of joints etc. in the connection.
Secondly, in the locating of the disc spindles upon the arc of a circle at dis-
tances of 18 degrees apart. The effect of this arrangement is that the projections
which are fixed to each wheel for the purpose of driving the succeeding wheel,
comes opposite a tooth in the wheel to which it is fixed, instead of opposite a
space, as would be the case if the discs were placed in a straight line. The advan-
tages of this arrangement being that a projection from the side of the tooth is all
that is required to turn the succeeding wheel and also that the arch form of the
machine allows of the free working of the toggle motion.
Improvements in Engine Counters or Revolution Indicators.
I, JAMES SCOTT MONRO, Marine Engineer, c/o Messrs. Walker Brothers & Co.,
168, Oxford Street, Glasgow, in the County of Lanark, Scotland, formerly of
44, Constitution Street, Leith, in the County of Midlothian, Scotland, do hereby
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declare the nature of this invention and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement:-
This invention relates to improvements in engine counters or revolution indi-
cators. An arrangement of jointed levers A, B, Fig. 1, commonly known as the
"toggle motion " is employed to actuate the ratchet lever C, Fig. 1, carrying
the pawl D, Fig. 1, which drives the units wheel E, Fig. 1. The advantage of
this arrangement is, that although an excessive amount of stroke be imparted to
the toggle motion, from its connection to a steam engine or other machine, the
stroke of the ratchet lever and pawl is not affected, as they cannot advance beyond
the position attained when the toggle motion reaches or passes the straight line,
thus ensuring that the units wheel shall come to rest in the exact position re-
quired. It is intended that an excess of stroke should be provided when first
making the connection, so as to allow for lost motion through wearing of. joints
etc. in the connection. The fulcrum stud F, Fig. 1, on which the toggle motion
oscillates, is fixed in the lever G, Fig. 1, and any wear of the toggle motion can
be compensated by advancing this lever slightly towards the right hand, and fix-
ing by the screw H, Fig. 1.
The toggle motion is actuated either by a link I, Fig. 1 attached to the central
joint, or by a lever J, Fig. 1, fitted into a recess in the end of lever A, at a suit-
able angle. Springs K, Fig. 1, attached to projecting arms on the levers A, and
B, Fig. 1, tend to raise the central joint of the toggle motion during the return
or idle stroke of the ratchet, even although the toggle motion has passed the
straight line.
A
At each complete revolution of the ratchet wheel E, Fig. 1 a steel pin e, Fig. 1
fixed in the side of it, gears with wheel E Fig. 1, which is placed to the left of
and close behind wheel E, thus turning wheel E to the extent of one tooth.
special striking lever e¹ Fig. 1, is mounted on the spindle of, and attached to
wheel E', so as to gear with wheel E Fig. 1, which is placed to the left of, but
considerably in front of wheel E¹. A series of similar wheels E³, E, E³, E,
follow, each one to the left of, and behind the preceding wheel, and each one,
except the last, carrying a pin, e³, e, es, Fig. 1, which gears with the succeeding
wheel. A pin may be fixed in wheel E, similar to the others, but the special
striker is preferred as by this arrangement wheel E can be placed midway between
the frames.
Detent springs L, Fig. 1, fixed on stays M Fig. 1, retain the wheels in their
proper positions between each movement.
The spindles of the gear wheels are located upon the arc of a circle at distances
of 18° apart. The effect of this arrangement is that the pin which is fixed in each
wheel for the purpose of driving the succeeding wheel, comes opposite to, and
can be easily fixed in a tooth, instead of opposite a space, where it could not be
so conveniently fixed, which would be the case if the spindles were placed in a
straight line. The arc arrangement also allows of the machine being much shorter
than it would otherwise be, and provides a suitable space in which the toggle
motion may work.
Enamelled or engraved discs N, Fig. 2, are fixed on the front ends of the
spindles, and show the numerals through suitable openings in a blinding plate.
The counter can be set to zero by means of a small screw-driver, fitting the cut
provided in the end of each spindle.
Sheet 1 of the accompanying drawings shows the arrangement of the works.
Sheet 2 shows the outer case, partly in section, and the arrangement of discs over-
lapping each other, also part of the blinding plate which is fixed on the door.
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:-
1st. The application of the toggle motion to actuate the ratchet lever, substan-

page_text: tially as described, and illustrated in the accompanying drawings, and for the
purpose specified.
2nd. The locating of the spindles which carry the gear wheels and numeral
dises, upon the arc of a circle at distances of 18° apart, substantially as described,
and illustrated in the accompanying drawings, and for the purposes specified.
Dated-this-19th-day of July 1899.