IMPROVEMENTS IN SPLIT SECOND TIME REGISTERS
Year: 1879

page_text: LETTERS PATENT to Philip Syng Justice, of 14, Southampton Buildings, in
the County of Middlesex, Engineer, for the Invention of "IMPROVEMENTS IN
SPLIT SECOND TIME REGISTERS." A communication from abroad by William
B. Fowle, of the City of Newton, County of Middlesex, in the State of
Massachusetts, United States of America, Gentleman.
Sealed the 19th December 1879, and dated the 27th September 1879.
PROVISIONAL SPECIFICATION left by the said Philip Syng Justice at the
Office of the Commissioners of Patents on the 27th September 1879.
PHILIP SYNG JUSTICE, of 14, Southampton Buildings, in the County of Middlesex,
Engineer. "IMPROVEMENTS IN SPLIT SECOND TIME REGISTERS." A communication
from abroad by William B. Fowle, of the City of Newton, County of Middlesex,
in the State of Massachusetts, United States of America, Gentleman.
This Invention relates to instruments for measuring to the nearest tenth of a
second, for instance, or the shortest intervals of time, for scientific or sporting
purposes, the class of instruments to which my Invention relates being those in
which "split second hands," so called, are employed to note the extent of the
interval of time sought. My improvements relate to certain mechanism by which
the two portions of the split second hand are operated.
In the accompanying Drawing Fig. 1 represents a face view or plan of the
mechanism embracing my improvements, and Fig. 2 a vertical cross section through
the watch and second hands.
A represents the pillar plate of the movement, and B the arbor of the "third"
pinion" of the movement, the pivot of such arbor, which extends through the plate
and which carries the principal feature of my improvements, being shown at a. D
represents a "heart cam" formed with a tubular hub b which loosely encompasses
the pivot a, such cam being prevented under ordinary circumstances from rotating
upon the pivot a by a spring C interposed between the hub and a shoulder b₁
formed upon the arbor B, the stress of this spring being sufficient to overpower the
stress of a tight hair spring, which in turn exerts its stress between the cam and a
toothed plate or disc carried by a friction collet E encompassing the hub of the
cam, as hereinafter explained, and yet being sufficiently loose to permit of the heart
[Price 6d1

page_text: being returned to its zero or normal position by the action of the push plate, also
to be described.
F represents the friction collet above alluded to, such collet loosely encompassing
the lower part of the hub b of the heart D, and being formed upon its lower end
with a collar or flange c which serves as a base to a circular disc or plate F, the
tubular bub d of which disc adheres with light friction to the collet E, and at its
upper end, which extends considerably above the top or outer end; such collet
carries the lowermost of the two split second hands, which is shown at G; the hub
of such hand G encompasses tightly the hub d of the disc in order that the said
hand G shall cling to the disc F as the collet E rotates within the hub of such disc,
when the latter is locked rigidly in position by a latch bar, to be hereinafter
explained.
The upper or outer one of the two split second hands is shown at H as having a
tubular hub which tightly encompasses the upper end of the hub "b" of the
heart D, so as to rotate with such heart, while the said hub fis held loosely within
the upper end of the hub of the disc F to avoid contact with the latter. A
washer is placed over the hand H upon the pivot a and a pin passed through the
latter, so as to compress the spring Ĉ upon the shoulder b¹ of the arbor B. The
minute hand pivot is shown at I, and its heart cam J while alongside of the two is
arranged upon the plate A, a thin plate K pivotted at one end to said plate A, as
shown, in order to adapt it to approach or recede from the two hearts, the office of
such plate K, which I term a push" plate, being to restore the hearts and conse-
quently the minute and double or split second hands to their normal or zero points.
To effect this the plate K has two spurs j, k, so disposed with respect to the hearts
that when pushed in toward such hearts they shall press against their peripheries
and restore them to their zero points.
"
The periphery of the disc F is indented or toothed, as shown in the Drawings,
and I pivot to the plate A and alongside of such disc a latch bar provided with a
spur m which extends through the bevel of the case and so adjusted with respect
to the disc that when pushed inwardly it shall engage and arrest the revolution of
the disc if the train is in motion, and when withdrawn permit the disc to rotate.
Between the heart D and the disc F and encircling the pivot a I arrange a coiled
hair spring n, one end of such spring being secured to the heart and the other to
the disc.
When the train is in motion and the disc F is free from control of the latch the
two hands travel together (provided the balance is free) by and with the pivot a,
as the heart D which carries the hand H clings to such pivot with sufficient friction
to overcome the stress of the spring C upon the arbor B, while the collet E which
carries the disc F and hand, G cling to the hub of the heart with sufficient friction
to travel with such heart.
To prevent injuring the hair spring n by a too long continued rotation of one
hand away from the other I affix to the under side of the disc F a stop pin c'
arranged in a concentric path with a second stop pin or post d rivetted upon the
top of the heart D. If the revolution of the hand H is continued throughout an
entire circle the two pins come in contact and further rotation of said hand H with
respect to the hand G is arrested. The post d also constitutes a support to one.
end of the hair spring n.
The operation of the mechanism is briefly as follows:-Supposing the main
spring to be wound up and the motion of the train arrested by the stopping of the
balance, as before explained, the two hands G, H, being together and standing at
the normal or zero point of the dial.
When it is desired to measure a short interval of time the latch bar "1" is first
turned into engagement with and so as to prevent rotation of the disc F and hold
the hand G motionless and the pendant knob turned in the direction to release the
balance, and put the arbor B and other hand H in rotation as well as the heart D,
the hand thus denoting the beginning of the interval of time to be noted and
the hand H travelling away from the first with the passage of time; the heart D.

page_text: also rotates with the arbor, while the collet E is stationary, thereby coiling up the
spring n and creating a power to restore the primary position of the hands.
As the interval of time to be noted expires the knob is turned in the opposite
direction and the balance is arrested, thereby stopping the hand H at this point.
The distance between the two points denotes upon the scale of the dial the interval
of time, and as the hands remain stationary until the knob is again returned the
interval of time may be leisurely noted.
To restore the two hands to their original position, that is, coincident with each
other, the latch is removed from the disc F, and the relaxation of the spring n
effects a rotation of the said disc, and the hand & returns to the heart H.
To ascertain the duration of another interval of time the above manipulation
may be repeated with the two hands standing together as left; or by pushing in
the push plate K the two hands may be returned together to their zero point.
It will thus be seen that by turning of the pendant knot in one or the other
direction the hands are arrested or allowed to travel, while by means of the latch
bar one of such hands is arrested while the other continues to travel, thus splitting
the second hand, while finally the pushing inward of the shank of the pendant
knob effects through an intermediate slide an inward movement of the push plate
and a restoration of the two hands together to the zero point.
The purpose of the heart spring C is to compel the two hands to travel in unison by
and with the arbor as the spring bends on the arbor sufficiently for this; but when
the toothed wheel is stopped by the latch the heart-spring slips about the arbor,

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Philip Syng Justice in the Great Seal Patent Office on the 23rd
December 1879.
PHILIP SYNG JUSTICE, of 14, Southampton Buildings, in the County of Middlesex,
Engineer. "IMPROVEMENTS IN SPLIT SECOND TIME REGISTERS." A communication
from abroad by William B. Fowle, of the City of Newton, County of Middlesex,
in the State of Massachusetts, United States of America, Gentleman.
This Invention relates to instruments for measuring to the nearest tenth of a
second, for instance, or the shortest intervals of time, for scientific or sporting
purposes; the class of instruments to which my Invention relates being those in
which "split second hands," so called, are employed to note the extent of the
interval of time sought.
My improvements relate to certain mechanism by which the two portions of the
split second hand are operated.
"
In the accompanying Drawing Fig. 1 represents a face view or plan of the
mechanism embracing my improvements; and Fig. 2 a vertical cross section through
the watch and second hands. A represents the pillar plate of the movement; and
B the arbor of the "third pinion" of the movement, the pivot of such arbor, which
extends through the plate, and which carries the principal feature of my improve-
ments, being shown at a; D represents a "heart cam
formed with a tubular
hub b, which loosely encompasses the pivot a, such cam being prevented under
ordinary circumstances from rotating upon the pivot a by a spring C interposed
between the hub and a shoulder b¹ formed upon the arbor B, the stress of this
spring being sufficient to overpower the stress of a tight hair spring, which in turn
exerts its stress between the cam and a toothed plate or disc carried by a friction
collet E encompassing the hub of the cam, as hereinafter explained, and yet being
sufficiently loose to permit of the heart being returned to its zero or normal
position by the action of the push plate, also to be described. E represents
the friction collet above alluded to, such collet loosely encompassing the lower
part of the hub b of the heart D, and being formed upon its lower end with
a collar or flange c which serves as a base to a circular disc or plate F, the
tubular hub d of which disc adheres with light friction to the collet E, and at its
upper end which extends considerably above the top or outer end such collet carries
the lowermost of the two split second hands, which is shown at G; the hub of such
hand G encompasses tightly the hub d of the disc in order that the said hand G
shall cling to the disc F as the collet E rotates within the hub of such disc when
the latter is locked rigidly in position by a latch bar, to be hereinafter explained.
The upper or outer one of the two split second hands is shown at H as having
a tubular hub f, which tightly encompasses the upper end of the hub b of
the heart D so as to rotate with such heart, while the said hub f is held loosely
within the upper end of the hub of the disc F to avoid contact with the latter; a
washer g is placed over the hand H upon the pivot a, and a pin passed through the
latter so as to compress the spring C upon the shoulder 61 of the arbor B. The
minute hand pivot is shown at I, and its heart cam J, while along side of the two
is arranged upon the plate A a thin plate K, pivotted at one end to said plate A, as
shown, in order to adapt it to approach or recede from the two hearts, the office of
such plate K, which I term a push plate, being to restore the hearts, and consequently
the minute and double or split second hands, to their normal or zero points. To
effect this the plate K has two spurs j, k, so disposed with respect to the hearts
that when pushed in towards such hearts they shall press against their peripheries
and restore them to their zero points.

page_text: The periphery of the disc F is indented or toothed, as shown in the Drawings,
and I pivot to the plate A and alongside of such disc a latch bar 7, provided with a
spur m which extends through the bevel of the case, and so adjusted with respect to
the disc that when pushed inwardly it shall engage and arrest the revolution of the
disc if the train is in motion, and when withdrawn permit the disc to rotate.
Between the heart D and disc F, and encircling the point a, I arrange a coiled hair
spring n, one end of such spring being secured to the heart and the other to the
disc.
When the train is in motion and the disc F is free from control of the latch the
two hands travel together (provided the balance is free) by and with the pivot a,
as the heart D which carries the hand H clings to such pivot with sufficient friction
to overcome the stress of the spring C upon the arbor B, while the collet E which
carries the disc F and hand G cling to the hub of the heart with sufficient friction
to travel with such heart. To prevent injuring the hair spring n by a too long
continued rotation of one hand away from the other I affix to the under side of the
disc F a stop pin c¹ arranged in a concentric path with a second stop pin or post d
rivetted upon the top of the heart D. If the revolution of the hand H is continued
throughout an entire circle the two pins come in contact, and further rotation of
said hand H with respect to the hand G is arrested. The post d' also constitutes a
support to one end of the hair spring n. The operation of the mechanism is briefly
as follows: Supposing the main spring to be wound up and the motion of the
train arrested by the stopping of the balance, as before explained, the two hands
G, H, being together, and standing at the normal or zero point of the dial. When
it is desired to measure a short interval of time the latch bar is first turned into
engagement with and so as to prevent rotation of the disc F, and hold the hand G
motionless, and the pendant knob turned in the direction to release the balance and
put the arbor B and other hand H in rotation, as well as the heart D, the hand
thus denoting the beginning of the interval of time to be noted, and the hand H
travelling away from the first with the passage of time; the heart D also rotates
with the arbor while the collet E is stationary, thereby coiling up the spring n and
creating a power to restore the primary position of the hands.
As the interval of time to be noted expires the knob is turned in the opposite
direction, and the balance is arrested, thereby stopping the hand H at this point.
The distance between the two points denotes upon the scale of the dial the interval
of time, and as the hands remain stationary until the knob is again returned, the
interval of time may be leisurely noted. To restore the two hands to their original
position, that is, co-incident with each other, the latch is removed from the disc F,
and the relaxation of the spring n effects a rotation of the said. disc, and the
hand G returns to the hand H. To ascertain the duration of another interval of
time the above manipulation may be repeated with the two hands standing together
as left, or by pushing in the push plate K the two hands may be returned together
to the zero point. It will thus be seen that by the turning of the pendant knob
in one or the other direction the hands are arrested or allowed to travel, while
by means of the latch bar one of such hands is arrested, while the other con-
tinues to travel, thus splitting the second hand, while finally the pushing in of
the shank of the pendant knob effects through an intermediate slide an inward
movement of the push plate, and a restoration of the two hands together to the
zero point. The purpose of the heart spring C is to compel the two hands to travel
in unison by and with the arbor, as the spring bends on the arbor sufficiently for
this, but when the toothed wheel is stopped by the latch the heart spring slips
about the arbor.
Having thus described the nature of the Invention of my foreign correspondent,
what I claim and desire to secure by Letters Patent is,-
First. The combination with the arbor and the heart cain D, of the disc F, friction
collet E, spring n, and the split second hands, carried one by the heart cam and the
other by the disc, substantially as set forth.

page_text: Second. The combination with the arbor and the heart cam D carrying one split
second hand, and communicating movement to the devices which carry the other
split second hand, of the heart spring C, substantially as set forth.
Third. In combination with the cam D and the disc F mounted on the arbor and
connected with one another by a frictional and spring connection as described, the
latch bar , substantially as and for the purpose set forth.
Fourth. The combination, substantially as set forth, of the minute heart cam J,
the heart cam D, and the disc F, mounted on the arbor and connected with one
another by a frictional and spring connection as described, the push plate K, and
the latch bar 1, for joint operation, substantially as described.
In witness whereof, I, the said Philip Syng Justice, have hereunto set my
hand and seal, this Twenty third day of December, in the year of our Lord
1879.
PHILIP S. JUSTICE. (L.S.)