Improvements in Steam Engine Indicators.
Year: 1894

page_text: Date of Application, 20th Feb., 1894-Accepted, 12th Jan., 1895
COMPLETE SPECIFICATION.
Improvements in Steam Engine Indicators.
I, WILLIAM HOUGHTALING, of 91 Sterling Street Bridgeport, County of
Fairfield, in the State of Connecticut, United States of America, Machinist, 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 and accompanying drawings:
--
This invention relates to an attachment to steam engine indicators already
in use and to the same improvements embodied in the construction of new
instruments.
To render the invention perfectly clear, I will now proceed to describe the same
with reference to the annexed drawings:
Figure 1, Sheet 1, is an elevation, partly in section of the principal parts of the
ordinary type of indicator with the new attachment connected therewith.
Figure 2 a plan view partly in section of the same.
Figure 3 a detached view partly in section of the clutch mechanism engaged.
Figure 4, Sheet 2, a side elevation of the diagram barrel with an improvement
and also showing the clutch mechanism in section.
Figure 5 a horizontal section of Figure 4.
Figure 6 a horizontal view through the line a-, Figure 4.
Figure 7, a modification of the device shown at top of Figure 4.
Figure 8, Sheet 3, a plan view partly in section of an entire cord pulley
attachment.
Figure 9 a sectional view of the clutch.
Figure 10 an end view of a part of the clutch showing ratchet and pawl-lever
engaged.
Figure 11 a view showing one position of the parts of the olutch engaged.
Figure 12 an end view of the pawl-lever and ratchet disengaged; and
Figure 13 a view of the spring pin in contact with the pawl-lever.
In the use of these instruments it is essential to overcome all lost motion between
the diagram barrel and the pulley, that connects by a cord with a reciprocating
part of the engine, and also that the parts should be operated by a positive motion
and with the slightest friction to insure certainty of operation.
In the use of a clutch engagement in transmitting motion from the cord pulley
to the diagram barrel it is also found desirable in practice to previously turn the
diagram barrel slightly forward and clear of its recoil stop so that when the
engagement is made the slight extra tension given to the cord will prevent
the barrel from slamming against its stop in its recoil movement.
My improvements, therefore, consist in devices, which I will more particularly
refer to hereinafter, to effect the results named in instruments of special construction
and also those now in use, and to manipulate the same by one or both hands of the
operator as desired.
Referring to the respective parts indicated in Sheet 1 of the drawings, in which
the same reference figures indicate corresponding parts in Sheets 2 and 3, 12 is
the diagram barrel with a retracting spring and cord groove at its base and 21 the
steam cylinder carrying the pencil mechanism all as ordinarily used in this class of
nstruments.

page_text: In this illustration the attachment embodying my improvements is applied to
the ordinary form of indicator already in use and is mounted upon the arm or base
plate 15 which is made interchangeable with a similar plate in the ordinary indicator
that supports the leading off cord guide pulley, so that all that is necessary in
applying the new attachment is to substitute the one fixture for the other, each
being secured to the base 13 by the nut 14.
The attachment is composed in this instance of a supporting base plate 15
provided with short standards 55 that form bearings for the worm shaft 6 to which
the cord pulley 22 is connected. The diameter of this pulley should be adapted
to a given length of stroke of the engine piston to transmit the desired amount of
motion to the diagram barrel to produce its extreme oscillation and for different
strokes of engine piston, pulleys of greater or less diameter must be substituted.
The clutch mechanism consists of the collar 5 fixed to the shalt 6, the sliding
collar 7 carrying the parallel pins 8 and 9, the clutch extension 10, and the loose
ring 11 surrounding the sliding collar 7.
The cord pulley 22 is fitted loosely upon the shaft 6 and connected with a
retracting spring 33 by means of the pin 44, its hub projecting with a cam face (see
Fig. 11, Sheet 3), and notched to form the clutch engagement with the extension 10
of the sliding pin 8. The object of this construction is to automatically disengage
the clutch bolt 10 by the reverse motion of the pulley 22 when the operator has
failed to engage the clutch at the proper time which is at the commencement of
the stroke of engine piston. The effect of this operation is to prevent further
movement of the diagram barrel, which returns to its normal position by the action
of its recoil spring, thus preventing any markings on the diagram sheet.
As I have before stated, in making the clutch engagement, it is desirable to
turn the diagram barrel slightly forward and clear of its recoil stop. To accomplish
this and avoid grasping the diagram barrel which disarranges the diagram sheet,
I have shown different adaptations herein of means for effecting this, the attachment
shown on Sheet 1 consisting of an anxiliary barrel 16 constructed with a toothed
ring 17 that engages with the worm on the shaft 6 of the clutch mechanism. This
barrel 16 is mounted on a spindle 18, rotates freely thereon, and is connected to
the diagram barrel 12, by means of the cord 19 which encircles and is secured at
one end to the diagram barrel 12 at its base, and to the auxiliary barrel 16 by
winding and securing it by passing it through one or more holes 20 or slots 21 and
holding its free end by means of a flat spring 25 connected to the hub 23 of the
barrel 16. This connects the clutch mechanism with the diagram barrel.
The device for turning the diagram barrel slightly forward consists in a loose
knob or thumb-piece 1 placed upon the projecting end of the spindle 18 and is
provided with a depending pin or stud 4 that engages when the knob 1 is turned
with a corresponding pin 3 projecting from the hub 23 of the auxiliary barrel 16.
These pins 3 and 4 project past each other and are relatively placed to be free
from contact when the clutch is disengaged from the cord pulley 22.
Previous to making the clutch engagement the knob is first turned to bring
the respective pins 3 and 4 in contact and by a slight further turn the respective
barrels 16 and 12 are advanced clear of the recoil stop 2 of the diagram barrel and
held in one hand until the clutch engagement is made with the other hand. The
instant the clutch engagement is effected, the pins move away from each other,
leaving the knob 1 stationary and free while the diagram oscillates in its operation.
It is obvious that the recoil stop may, if desired, be applied to, the auxiliary
barrel as shown at a, without changing the operation.
The thumb piece 1 is also of use in arresting the oscillations of the barrel, after
a diagram has been taken.
This is effected by rotating the thumb piece sufficiently to bring the pins 3 and 4
in contact which will retard the recoil oscillation of the barrel and cause the
clutch mechanism to be automatically disengaged.
In Sheet 2, I have shown a modification of my invention wherein in the
construction of new instruments the clutch mechanism with its worm gear is

page_text: connected directly with the diagram barrel 12 by constructing the latter with a
toothed ring at its base, and applying the device for previously advancing the
barrel, in making the clutch engagement, directly at the top of the diagram barrel,
its spindle being elongated for such purpose.
In Figure 7, Sheet 2, a modified construction is shown, in which the bottom of
the hub of the knob 1 may be constructed with a cam surface and shoulder and
the projecting part of the diagram barrel correspondingly made, as a substitute
for the pins 3 and 4 or a hand lever as shown at 26 may be connected to the base
of the barrel to effect the same purpose.
In both instances described, both hands of the operator are necessary to
manipulate the instrument. I have therefore, shown in Sheet 3 a form in which
both operations that of first advancing the diagram barrel and subsequently making
the clutch engagement, may be accomplished with one hand.
In this modification of my invention a ratchet plate 29 and pawl lever 30 is
attached respectively to the collar 7 and loose ring 11, the pawl having an extension
which serves as a handle for the operator.
The pawl is maintained in its free position as shown in Figure 12 by means of
the spring 32 and pin 31 which constantly bears upon the inner surface of the
extension or handle of the pawl lever.
In operation the clutch bolt 10 being drawn back and free through the medium
of the loose ring 11 on the sliding collar 7 the pawl 30 is engaged with the
ratchet 29 by the same hand of the operator when the loose ring carrying the
pawl 30 is turned slightly backward, the movement being transmitted to the diagram
barrel. The clutch engagement is then made by moving the sliding collar 7
inward the same as in the other modifications.
Upon the proper engagement of the clutch extension 10, the pawl 30 is instantly
disengaged, due to the rotary motion imparted to the ratchet 29 by the action of
the inclined portion of the ratchet teeth, the pawl being held in its free position
by the contact of the pin 31. In this instance it will be seen that the entire
manipulation of the attachment is effected through the medium of the loose collar 11
only necessitating the use of but one hand of the operator.
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. An attachment for steam engine indicators consisting of an auxiliary barrel
adapted to oscillate co-incident with the diagram barrel combined with a cord
pulley connecting with a reciprocating part of the engine and a clutch mechanism
for connecting and disconnecting the parts for operation.
2. In combination with the diagram barrel of a steam engine indicator, an
auxiliary barrel having a cord connection therewith, a clutch mechanism geared to
said auxiliary barrel, and means for slightly rotating the same previous to the
clutch engagement, as set forth.
3. An attachment for steam engine indicators comprising an auxiliary barrel
adapted to oscillate coincident with the diagram barrel, a clutch mechanism, and
means for independently rotating the diagram barrel, supported by an arm projecting
from the diagram barrel spindle, made interchangeable with the arm carrying the
leading off cord mechanism.
4. In a steam engine indicator, the combination with the diagram barrel, of a
hand device for rotating said barrel connecting directly therewith, substantially as
and for the purpose specified.
5. In a steam engine indicator, the combination of the diagram barrel, an
independent hand device capable of direct communication therewith, for rotating
the same or arresting its rotation, as set forth.
6. In a steam engine indicator, the combination with the diagram barrel, of a
hand device connecting directly therewith for rotating said barrel and a clutch
mechanism adapted to automatic disengagement, as set forth.

page_text: 7. In a steam engine indicator, the combination with the diagram barrel provided
with the pin 3 and the thumb-piece 1, provided with the pin 4, substantially as and
for the purpose specified.
8. In a steam engine indicator attachment, in which the shaft of the cord pulley
is geared with the diagram barrel and provided with a clutch for communicating
the motion of said pulley at will, the combination of means for turning the shaft
independent of the pulley so that the diagram barrel may be slightly rotated for
the purpose explained.
9. The combination of the diagram barrel, the pulley shaft geared therewith, a
collar fixed to said shaft, and an adjacent collar loosely mounted on said shaft, said
collars being provided with an interposed device for connecting them at will for
the purpose set forth.
10. The combination with the fixed and loose collars as described, of an engaging
pawl and ratchet attached respectively therewith, said pawl having an extended
part for operating the same, and a brake connection for maintaining it in position,
as set forth.
Dated this 19th February 1894
GEORGE BARKER,
77, Colmore Row, Birmingham, Agent.