Improvements in Actuating Mechanism for Dial Indicators.
Year: 1892

page_text: COMPLETE SPECIFICATION.
Improvements in Actuating Mechanism for Dial Indicators.
A communication by CHARLES F. HOLT, Gentleman, and WILLIAM S. STAR,
Apothecary, both of the City of New London, in the County of New London
and State of Connecticut, United States of America.
I, WILLIAM PHILLIPS THOMPSON, F.C.S. M.I.M.E. of the Agency for
Foreign Patent Solicitors, 6 Lord Street Liverpool, and 6 Bank Street,
Manchester both in the County of Lancaster and 323 High Holborn in the County
of Middlesex, Civil 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 is specially adapted for use with that class of mechanisms in which
a graduated dial, and intermittently moving pointers, are provided to register
certain movements at a distance, as for example in so called electric clocks, which
may be distributed at various distant points and controlled by a single time-piece
centrally located.
In the annexed drawings,
Figure 1 is a front-face view of a complete indicator embodying this improve-
ment, and
Figure 2 a similar view with the dial and hands removed to expose the opera-
tive parts of the indicator.
Figure 3 is a cross-sectional view of a complete indicator on line x-x of
Figure 2, and
Figure 4 is a similar view on line 2-2.
Figure 5 shows a central, sectional view, considerably enlarged, of the hands and
the pinions to which they are attached.
In the drawings, a denotes the enclosing case of the indicator, the operative
parts being pivoted in and between the front and rear plates (bc).
To the front-plate 6 is secured a graduated dial d. The movements of the
hands or pointers are substantially the same as in ordinary electric clocks, that is
to say, one of said hands is caused to travel with a step by step" movement
and, when it has completed the round of the dial, the other hand moves forward
one step.
The dial here shown is intended for use with a ship's log, the inner graduated
circle and shorter pointer being provided to register each quarter mile travelled,
while the outer graduated circle and longer pointer register every ten miles (that
is, every complete revolution of the short pointer).
e indicates a central pivot, to which the longer pointer is fastened. This pivot
has secured to it a gear el having, for the present purpose, 100 teeth.
On the front end of said pivot e is a tubular shaft having secured near its inner
end a gear fl with 40 teeth, and to its outer end the shorter pointer. The number
of teeth in the described gears may, of course, be varied according to the desired
distances to be registered.
A second pivot g, supported between the front and back plates of the indicator,
bears a gear g¹ that meshes with the gear f¹ and also a mutilated gear g³ with a
single tooth that meshes, at stated times, with the larger gear el. The gear fl
serves as the driver of the train and it will be understood that when said gear is
set in motion, the large gear e¹, will be moved forward only one tooth for each
complete revolution of the driver.
•
Gear is controlled and moved step by step, by a novel arrangement of pawl
and escapement, forming the most essential feature of this invention which will now
be described.
'

page_text: A denotes an electro-magnet which we will assume is in the line of an electric
circuit which includes the usual battery and also a ship's log, or other circuit
maker and breaker.
gear
i denotes the armature of the magnet, pivoted to a bracket i¹, secured to the back
plate of the indicator, and bearing at its inner end a pawl which engage
successively the teeth of gear f¹. When the electric circuit is closed and the armature
rocked on its pivot, the pawl k advances a distance equal to a single tooth and the
gear is correspondingly moved. Projecting upward from the armature lever i,
near the end that co-acts with the magnet, is an arm m whose end is bent toward
gear and of such size and length that it may enter between the teeth of said
when the armature is raised out of contact with the magnet, as in Figure 2 of the
drawings. Jointed to the projection m, near its end, is a lever n that is pivoted to
the front-plate of the indicator, and is formed with a pawl shaped, short arm that
is rocked to enter between the teeth of gear f¹ when the armature is drawn into
contact with the magnet. The described arrangements of armature and
connections provide a pawl for actuating gear f¹ along tooth by tooth and also a
double system of locking bolts or escapement, which permit the said gear to be
moved only one tooth at a time.
In order to further prevent any accidental displacement of gear 1, a frictional
or so called " drag" spring o is preferably provided, which may be secured to one
of the plates b-c, or to a rod extending from plate to plate. One end of said spring
bears lightly on the face of gear f¹, and serves to hold said gear when not
positively engaged and controlled by the described pawl and compound escapement.
A spring pawl or detent s is also provided, which is suitably fastened to or
between the plates of the indicator, and whose free end engages one of the teeth of
the large gear e¹. This detent serves to hold gear e' at all times in proper relation
to the mutilated gear 9 so that the single tooth of the latter shall always mesh
properly with the teeth of the former. The mutilated gear 92 could be provided
with any number of teeth, instead of one, as here shown, but, for the present form
of indicator, one only is required.
This device, as a whole, is simple in construction, inexpensive to produce and has
the further advantage of requiring but little power to operate. The pointers are
secured to their respective pinions by thumb-nuts which allow said points to be
released and set in any desired position on the dial.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, as communicated to me by
my foreign correspondents, I declare that what I claim is :-
1. In combination with a train of gearing controlling the movements of two
pointers as set forth, and an electro-magnet, an armature of lever form having an
actuating pawl and a locking pawl as described, and an independently pivoted
locking pawl connected with said armature-locking pawl, substantially as specified.
2. In combination with a toothed wheel, an angle lever having an actuating
pawl at one end and a locking pawl at the other end, and an independently pivoted
locking pawl connected with said angle lever in manner and for the purpose
specified..
Dated this 23rd day of May 1892.
WM. P. THOMPSON & Co.,
Agents for the Applicant.