Year: 1886

page_text: I, OLIVER IMRAY of No. 28 Southampton Buildings, Chancery Lane in the
County of Middlesex, Fellow of the Institute of Patent Agents do hereby declare
the nature of this invention to be as follows:-
My invention relates to a speed indicator or apparatus for indicating and
registering speed of rotation in cases where fluid under pressure is available as
for instance in an engine room or in a railway train having its brakes worked by
compressed air. For this purpose I arrange the sliding stem of a centrifugal
governor to bear directly or indirectly against one side of a flexible diaphragm
within a chamber that is provided on the other side of the diaphragm with an
inlet and an outlet valve, so as to admit by the one, fluid under pressure and to
discharge by the other, the fluid so admitted or a portion thereof. These valves
are both worked by the diaphragm, and as a convenient and simple construction
for that purpose I attach to the diaphragm directly or indirectly a stem sliding
through an inlet and an outlet aperture and filling the same so that there is no
passage for fluid except very slight leakage. Certain parts of the length of the
stem I groove or flatten, so that when these parts are in the apertures there is
passage for fluid. The apparatus works in the following manner. The centrifugal
governor being driven by the machine or shaft the speed of which it is desired to
ascertain, its stem presses against the diaphragm with more or less force as the
speed of rotation is greater or less. The diaphragm is thus moved so as to open
the inlet valve whereupon the pressure of the admitted fluid acts in opposition to
the pressure of the governor stem moving the diaphragm back until the inlet valve
becomes closed or nearly so and then if the pressure of the fluid within the
diaphragm chamber still exceeds that which is due to the centrifugal force of the
governor, the diaphragm is moved farther back until the outlet valve becomes
opened relieving in part the fluid pressure on the diaphragın. This pressure in the
diaphragm chamber is thus always regulated automatically so as to balance the
centrifugal force of the governor and a pressure gauge connected to the diaphragm
Pine 21

page_text: chamber will therefore give an indication by which the speed of the governor can
be ascertained. The pressure gauge may be arranged to act like a steam engine
indicator recording on a moving surface a diagram shewing the varying speed
during a given period. The pressure in the diaphragm chamber may also be
arranged to act on a valve so that when the speed attains a predetermined maxi-
mum this valve is opened admitting steam or other fluid under pressure into a
cylinder to act on a piston working a regulating valve or brake or both, so that
the speed becomes moderated.
Although I have described the action of the indicator as being effected by air or
fluid under pressure, obviously by suitable inversions the action may be effected by
rarefied air or fluid under atmospheric pressure.

page_text: I, OLIVER IMRAY, of No. 28 Southampton Buildings, Chancery Lane in the
County of Middlesex, Fellow of the Institute of Patent Agents, 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 a speed indicator or apparatus for indicating and
registering speed of rotation in cases where fluid under pressure is available as,
for instance in an engine room or in a railway train having its brakes worked by
compressed air. For this purpose I arrange the sliding stem of a centrifugal
governor to bear directly or indirectly against one side of a flexible diaphragm
within a chamber that is provided on the other side of the diaphragm with an
inlet and an outlet valve, so as to admit by the one fluid under pressure and to
discharge by the other the fluid so admitted or a portion thereof. These valves
are both worked by the diaphragm, and as a convenient and simple construction
for that purpose I attach to the diaphragm, directly or indirectly, a stem sliding
through an inlet and an outlet aperture and filling the same so that there is no
passage for fluid except very slight leakage. Certain parts of the length of the
stem I groove or flatten, so that when these parts are in the apertures there is
passage for fluid. The apparatus works in the following manner. The centrifugal
governor being driven by the machine or shaft the speed of which it is desired to
ascertain, its stem presses against the diaphragm with more or less force as the
speed of rotation is greater or less. The diaphragm is thus moved so as to open
the inlet valve whereupon the pressure of the admitted fluid acts in opposition to
the pressure of the governor stem moving the diaphragm back until the inlet valve
becomes closed or nearly Bо and then if the pressure of the fluid within the
diaphragm chamber still exceeds that which is due to the centrifugal force of the
governor, the diaphragm is moved farther back until the outlet valve becomes
opened relieving in part the fluid pressure on the diaphragm. This pressure in the
diaphragm chamber is thus always regulated automatically so as to balance the
centrifugal force of the governor and a pressure gauge connected to the diaphragın
chamber will therefore give an indication by which the speed of the governor can
be ascertained. The pressure gauge may be arranged to act like a steam engine
indicator recording on a moving surface or diaphragm shewing the varying speed
during a given period. The pressure in the diaphragın chamber may also be
arranged to act on a valve so that when the speed attains a predetermined maxi-
mum this valve is opened admitting steam or other fluid under pressure into a
cylinder to act on a piston working a regulating valve or brake or both, so that
the speed becomes moderated.
Although I have described the action of the indicator as being effected by air or
fluid under pressure, obviously by suitable inversions the action may be effected by
rarefied air or fluid under atmospheric pressure.
The accompanying drawings represent the construction of a speed indicator
according to my invention, Fig. 1. is a longitudinal section, Fig. 2 an end view
partly in section with the cover shewn in Fig. 3 removed to shew the interior,

page_text: Fig. 4 is a plan partly in section, Fig. 5 is a front view, and Fig. 6 is a part section
to an enlarged scale shewing the inlet and outlet ports and the sliding stem which
governs them. In all these figures like parts are marked by similar letters and
figures of reference.
.
A is a cylindrical casing and cover screwed to a front part B which forms a
pulley to be driven by a band at any suitable speed relatively to that of the shaft
of which the speed has to be indicated. Within the casing A extends from the
front part B an elongated boss C which is fitted to revolve on the stationary
tubular bearing S as on an axle and is held lengthwise by washers UV and
nut W.
At the rear end of the boss C project two brackets D on which are
pivotted at E bell crank levers having heavy horizontal arms F, and vertical
arius G which bear against volute rails t projecting from a disc H. The disc H is
fixed by a nnt h on a spindle I which passes through the bearing S free to revolve
and slide therein. From an oil cup Z lubricant is supplied to the outer and inner
surfaces of S. The end of the spindle I bears against a piece J which, in its turn,
bears against a spindle K that is free to slide, but is prevented from turning by a
stud b engaging in a chase in K. The spindle K bears against a piston L in front
of which is a flexible diaphragm M held round its outer edge by a boss O clamped
in the pedestal T of the apparatus by a screw cover L¹, and round its inner edge
by a cap P screwed into the piston L. Within the cavity of the piston L is held
with certain freedom the head of a sliding rod or needle N which operates as a
slide valve as it moves to and fro in a central hole bored along the boss O. This
hole is crossed first, by a hole 1 which communicates with a supply of fluid under
pressure such as compressed air, and secondly, by a hole 2 which by a channel 3
communicates with the space 4 in front of the diaphragm M. The longitudinal
hole in which the needle N is fitted terminates in front in an outlet 5 which is
preferably guarded by a screw cap R to prevent noise of escaping fluid. The
needle N has part of its side cut away at two places, or it might be merely
reduced in diameter at these places to form passages for air; when the needle
moves towards the right the passage at its end makes communication from 4 by
the passages 3 and 2 to 5 aud so allows escape of air from the space 4; when the
needle moves to the left its other passage makes communication from 1 to 4 and so
admits fluid under pressure to the space in front of the diaphragm M, which space
communicates by a side branch 7 (Fig. 5) with a pressure gauge. When the
pulley B and casing A with the boss C, its brackets D and the weights F, also the
spindle I are all caused to revolve together, the weights. F tend by centrifugal
force to move outwards, and the arms G press the disc H towards the left, tending
thereby to push the spindles I, J and K, the piston L and the diaphragm M in
opposition to the fluid pressure in the space 4. If this pressure be such that it is
overcome by the push on the diaphragm, the needle N is moved to the left making
a communication with the passage 1 and so admitting fluid under pressure into
the space 4. If, on the other hand, the pressure in the space 4 is greater than is
necessary to resist the push against the diaphragm, the needle N moving towards
the right puts the passage 2 in communication with 5, thus allowing escape of
fluid from the space 4 and reducing the pressure therein. In this manner so long
as there is a supply of fluid to the inlet 1 at a pressure somewhat greater than the
maximum pressure required to counteract the push on the diaphragm resulting
from centrifugal force, the fluid pressure in the space 4 is automatically adjusted
exactly to balance that force as it is transmitted to the diaphragm, and consequently
the pressure gauge connected with the space 4 gives an indication by which the
centrifugal force and, consequently, the speed of revolution can be ascertained. As
the centrifugal force and corresponding pressure are proportional to the square of
the number of revolutions, the pressure gauge employed may be graduated with
divisions corresponding with squares, so that the number of revolutions can be read
directly from the gauge without computation.
The pressure of the fluid in the space 4, besides being employed to act on a
'gauge to indicate speed, may obviously be applied to act on a piston or diaphragm

page_text: connected to a valve or other regulator for the purpose of controlling the speed of
the engine or machine from which the instrument is worked.
In order to correct the instrument for wear of the driving pulley B the disc H
has on it two volute segments t against some part of which the arms G bear, by
turning this disc H a little round relatively to the other revolving parts, the
bearing points of the arms G on the segments t can be adjusted at greater or less
distance from the centre, and consequently the leverage with which the arms F act
on the diaphragm can be increased or diminished. For thus adjusting the leverage
the spindle I is provided with a stud i free to slide in the groove of a screw cap x.
By turning the cap a partly round, the spindle I and the disc H are turned partly
round relatively to the other revolving parts. The screw cap x is consequently
made with an index working over graduations as shewn in Fig. 3.
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. The construction and use of a speed indicator applicable also as a regulator,
wherein the centrifugal force of revolving loaded arms pressing in one direction
a diaphragm is resisted by fluid pressure automatically adjusted to balance the
centrifugal force by means of a slide valve moved by the diaphragın, the fluid
pressure so adjusted indicating on a gauge the speed of revolution or being applied
to work a regulator, substantially as herein described.
2. In a speed indicator or regulator such as is referred to in the preceding claim,
in combination with the diaphragm M, the needle N, and the passages governed by
it as a slide valve, substantially as herein described and particularly illustrated by
Fig. 6 of the drawings.