Improvements in Steam-engine and like Indicators.
Year: 1899

page_text: PROVISIONAL SPECIFIC
Improvements in Steam-engine and like Indicators.
We, LEWIS ROBERT DORAN, Gallowflat House, Rutherglen, Engineer, and
ARTHUR TAGGART, 30, Sutherland Terrace, Glasgow, Engineer, do hereby declare
he nature of this invention to be as follows:--
This invention relates to improvements in indicating devices specially adapted
o indicators for registering pressures in steam or other engines and has for its
bject to facilitate the changing of the diagram cards especially when running at
high speed; and also to provide more efficient means for multiplying the motion
mparted to the recording pencil.
in accordance with our invention we construct the paper and cord drums
separate from each other and mount them upon the central supporting spindle
in the same relative positions to those of existing indicators each being under
the influence of an independent spring. The cord drum is rotated in the
usual way and the paper drum is driven therefrom by a pin or stud which
comes in contact with a similar pin or stud arranged in the path of the former.
The lower end of the paper drum is provided with teeth to receive a detent in
the usual way, but in place of employing an ordinary detent which causes the
paper drum to receive a shock when the stop of the cord drum lifts it off at
each stroke and thus adds to the difficulty of getting on a card, we may employ
a detent or pawl acted upon by a flat or other spring and carried by a ring,
sleeve or collar capable of being rotated or partially rotated by a knob or handle.
In order therefore to arrest the paper drum the aforementioned collar or sleeve
is rotated, causing the detent or pawl to engage with one of the teeth and by its
continued rotation in a direction opposite to that exerted by the drum's spring
remove the pin of the paper drum out of the reach of the cord-drum pin.
The sleeve may be retained in position by a horse shoe shaped split ring
situated above same which may also be formed with stops or projection for
regulating the extent of travel of the pawl.
To re-start the drum the pawl is returned to its former position. This
arrangement ensures the drum starting without shock as the detent is not
released from the paper drum until the tension of the latter's spring is being
borne by the pin of the cord drum.
Further, in order that the motion imparted to the recording pencil may be
more efficiently multiplied, we pivot the pencil carrying arm to a short link
which in turn is pivoted or hinged to a standard or arm mounted upon any
A pair of toggles or hinged links are pivoted
convenient part of the indicator.
to the beforementioned standard and to a point upon the pencil carrying arm
lazy tongs" and being such that
respectively, the arrangement resembling a
when one of the toggles is subjected to a very slight motion from the piston
through the piston rod and connecting link a very considerable motion is given
to the pencil thus producing a diagram of greater exactitude. One of the
guide of
toggles may be fitted with a pin or projection arranged to work in a
suitable form for the purpose of securing a perfectly vertical motion.

page_text: With this indicator also we may attach the end of the spring to the piston
within the cylinder by passing the end thereof through an aperture formed in a
stud attached to the piston and screwed into the end of the piston rod, thus
lightening the weight of the moving parts. The end of the spring may be
retained in position by brazing or otherwise.
Also if desired we may mount the pulley for guiding the cord to the drum,
in a swivelling bearing supported by a split socket within which it is retained
by a pinching or clamping screw. By this means the cord is always led directly
to the centre of the drum no matter at what angle it may be relatively with the
indicator.
Dated this 8th day of September 1800
Improvements in Steam-engine and like Indicators.
We, LEWIS ROBERT DORAN, of Gallowflat House, Rutherglen, near Glasgow,
Engineer, and ARTHUR TAGGART, of 30, Sutherland Terrace, in the City of
Glasgow, 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:-
This invention relates to improvements in indicators for steam or other
engines and has for its object to facilitate the changing of the diagram cards
especially when running at high speed and also to provide more efficient means
ior multiplying the motion imparted to the recording pencil.
The invention is illustrated by the accompanying drawings, Fig. 1 being a
vertical section of our improved indicator and Fig. 2 a plan of the same with the
cylinder cover and parallel motion removed.
In accordance with our invention the paper drúm A and cord drum B are
separate from each other and are mounted upon the central supporting spindle C
in the same relative positions to those of existing indicators each being under
the influence of an independent spring A', B¹, respectively. The cord drum B
is rotated in the usual way and the paper drum A is driven therefrom by a pin
or stud E arranged in the path of a pin or stud F on the cord drum B. In
order that a new card may be placed around the paper drum A whilst the cord
drum B is connected to the engine, the lower end of the paper drum A is pro-
vided with teeth A³ to receive a detent in the usual way, but in place of em-
ploying an ordinary detent which causes the paper drum A to receive a shock
when the stop of the cord drum B lifts it off at each stroke and thus adds to
the difficulty of getting on a card, we may employ a detent or pawl G acted
upon by a flat or other spring H which normally holds it out of action, and
centred at G¹ on a ring sleeve or collar I capable of being rotated or partially
rotated around the outside of the cylinder K by a knob or handle J to bring it
into action. In order to arrest the paper drum A the aforementioned collar or
sleeve I is rotated to the position shewn by the dotted lines, Fig. 2, causing
the detent or pawl G to engage with one of the teeth A2 and by its continued
1otation in a direction opposite to that exerted by the springs, it removes the
pin E of the paper drum out of the reach of the cord drum pin F.
The sleeve I may as shewn be retained in position by a horse shoe shaped
ring M situated above the sleeve I and entering an annular groove K¹ in the

page_text: ylinder K, which latter may also be formed with stops or projections K³ for
egulating the extent of travel of the sleeve I.
To restart the paper drum A the sleeve I is returned to the position indicated
n full lines, Fig. 2, which shews the detent G just leaving the teeth A². This
atter movement ensures the drum A starting without shock as the detent G is
not released from the teeth A2 of the paper drum A until the tension of the
atter's spring A¹ is being borne by the pin F of the cord drum B.
Further, in order that the motion imparted to the recording pencil may be
more efficiently multiplied, we pivot the pencil carrying arm N to a short
link which in turn is pivoted or hinged to a standard or stationary arm P
mounted upon any convenient part of the indicator. A pair of toggles or hinged
links Q, R, are pivoted respectively to the beforementioned standard P and
to a point N¹ upon the pencil carrying arm, the arrangement resembling a
lazy tongs" and being such that when one of the toggles Q is subjected to a
very slight motion from the piston S through the piston rod S₁ and connecting
link T a very considerable motion is given through the toggle R to the pencil
arm N thus producing a diagram of greater exactitude. One of the toggles.
preferably the toggle R, may be fitted with a pin or projection R' arranged to
work in a guide U of suitable form for the purpose of securing a perfectly
vertical motion.
With this indicator also we may attach the end of the spring V to the piston S
within the cylinder K by passing the end thereof an aperture formed in a
stud Wattached to the piston S and screwed into the end of the piston rod S¹,
thus lightening the weight of the moving parts. The end of the spring W
may be retained in position by brazing or otherwise.
Having now particularly described and ascertained the nature of our said
invention, and in what manner the same is to be performed, we declare that what
we claim is:-
1. An indicator for steam or other engines the several parts of which are
constructed, combined and arranged to operate, substantially as described.
2. An indicator for steam or other engines comprising a cord drum, an inde
pendent paper carrying drum having a series of teeth thereon and mounted
upon the same spindle as the cord drum, springs controlling these drums, a
pencil carrying arm arranged in proximity to the paper drum and forming one
element of a parallel motion consisting of a link jointed to said pencil arm and
to a stationary standard, a pair of toggle links connected to the standard and to
the pencil arm, and also connected by a short link to the piston rod and a
detent or pawl centred on a movable collar or sleeve capable of being rotated
to bring said detent into engagement with a series of teeth on the paper drum,
substantially as and for the purpose set forth.
a
stud
in
3. In an indicator for steam or other engines, the combination with a paper
drum having a series of teeth thereon, and mounted on a central spindle, of a
drum,
the
pin secured
or
spring for controlling said
a spring
paper drum, a cord drum independent of the paper drum,
a pin or stud therein in engagement
for controlling the cord drum and
with the paper drum, so that the paper and cord drums normally rotate together,
a detent or pawl adapted to engage the teeth on the paper drum, a movable
collar or sleeve on which said detent or pawl is centred capable of being rotated
to bring the detent into engagement with the teeth upon the paper carrying
0 drum, to turn said drum to such a position that its stud is held out of the path
of the pin on the cord drum, and a spring bearing on said pawl and normally
holding it out of engagement with the teeth, substantially as and for the purpose
set forth.
4. In an indicator for steam or other engines, the combination with a rotating
5 paper drum of a parallel motion consisting of a pencil carrying arm, a link con-
necting said pencil arm to a stationary standard, a pair of toggle links con-

page_text: nected to said standard and to the pencil arm, a guide pin on one of the toggle
links, a stationary guide in which said pin moves, and a short link connected
to the other toggle link and to the piston rod, substantially as and for the pur-
pose set forth.
WALLACE FAIRWEATHER,
Of the Firm of Cruikshank & Fairweather,
Chartered Patent Agents,
62, Saint Vincent Street, Glasgow
Agent for the Applicants."