Year: 1887

page_text: We, MARTIN VAN BUREN ETHRIDGE, HENRY EDWARD WAITE, and JOHN SWANN,
all of 6 Standiford Street. Boston in the County of Suffolk and State of Massachusetts
in the United States of America, Gentlemen, 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 an improvement in that class of clocks commonly known
as twenty four hour clocks, in which the hours, of the day are indicated by a
series of numbers from one to twenty four instead of repeating a series of from one
to twelve twice.
The object of the invention is to improve the striking mechanism by substituting
for the single bell or gong, two bells, or a bell and gong, a blow upon one of
which shall indicate ten, two, blows, twenty, and a blow upon the other the numerals,
one to ten.
The invention further consists in the means employed for reducing the rotation
of the snail to one revolution in twenty four hours; the construction and
arrangement of the hammer and its operating mechanism; the additional hand for
indicating universal time, whereby a dial is provided with which local time and
universal time can be indicated simultaneously on a face having a single circle of
twelve divisions; the method of cheaply constructing the spindles which constitute
the improved dial used in connection with this invention, said method consisting in
certain steps to be hereinafter specified; and it also comprises certain other details of
construction and arrangement as will be hereinafter fully described.
Fig. 1, is the perspective of the mechanism of a clock provided with our improved
snail operating gear, and the hour striking device.
Fig. 2, is a front view of the face partly in section.
Fig. 3, is a plan enlarged of the slotted ring which governs the movement of the
hammer.
Fig. 4, is an enlarged view of the striking rack.
Fig. 5, is a perspective showing the hands and shafts upon which they are
carried.
F fio fant elevation

page_text: Fig. 7, is a vertical section in the rear of the front plate and parallel therewith.
Fig. 8, is a top plan showing the general arrangement of parts with relation to
each other.
Fig. 9, is a plan view of the equalizing mechanism for the main spring.
Fig. 10 is an elevation of the same.
Fig. 11, is a front view of a spindle constructed by our improved process.
Fig. 12, is a perspective view of a numeral block shell.
Fig. 13, is a view of the turnstile before it is bent into the shape to be attached
to the spindle.
Fig. 14, is a top plan of turnstile after it has been thus bent.
Fig. 15, shows molds for fashioning the numeral blocks and numeral block
shells.
In all these figures, like parts are indicated by the same letters of reference, A,
being the supporting case or frame, which carries the operative parts of the clock
B, and, B¹ the two plates attached to case, A, in which are formed the journal
bearings for the several rotary shafts carrying the clock gear.
The time train of gearing in this clock is substantially the same as that in
common use, and being therefore well known requires no specific description. The
devices for striking the hours are to a great extent new and will therefore be fully
described. As the clock is intended to indicate the whole twenty four hours of a
day, instead of half that time it is necessary that the snail wheel, C, should be twice
as long in making a complete revolution as in the twelve hour clock.
This is accomplished by placing the snail wheel and its connected driving gear, C,
upon a stud, a, projecting from the plate. B, motion being communicated to said gear
wheel, (, by a pinion, C, having half as many teeth as the wheel, C, and mounted
upon the hollow shaft, D, which carries the hour hands of the clock. It will thus be
apparent that the snail wheel will make but a single revolution while the shaft, D, is
making two.
The periphery of this snail, C, is cut into a series of cam teeth which governs
the stroke of the striking hammer, as does the same device in the ordinary clock
movement, with this difference, that while the snail of the ordinary clock movement
has its periphery cut into a regularly increasing series to give the stroke from one
to twelve this is cut so as to give one stroke for one o'clock, two for two o'clock, and
so on up to nine o'clock, which is indicated by nine strokes, then one for ten o'clock,
two for eleven, and so on up to nineteen, which is indicated by ten strokes. The
reasons for this change in the formation of the snail will be apparent when it is
understood that both a gong and bell, or their equivalents are used to indicate the
time, each stroke upon the bell indicating a unit, while each stroke upon the gong
represents ten.
Only one hammer, E, is used to make the stroke, which is accomplished by making
the position of the hammer adjustable to the front and rear, so that when units are to
be struck it shall be opposite the bell, F, and when striking tens opposite the gong, F1,
the bell and going being secured to the case, A, in suitable position to receive the
blows. As the same material is not the best for striking upon both the bell and
gong, the hammer is provided with striking surfaces composed of different materials.
The part, b, which comes in contact with the bell, F, being preferably of lead,
while the part, 61, which comes in contact with the gong is faced with leather.
The striking arm, E', to which the hammer is attached is pivoted to an adjustable
lug, G¹, secured at any desired point on the rocker shaft, G, by a set screw or
other suitable means. The pivoting of the striking arm to this lug allows the
hammer to swing laterally so as to be brought into a position of contact with
either bell or gong, as may be desired, while the connection with the rocker shaft
allows it to swing in the same manner as the ordinary striking arm and hammer in
making the stroke.
To give the desired lateral movement to the striking arm a cam ring, H, fig. 3,
having its periphery notched or slotted as hereinafter described is secured to the
wheel, H, attached to the weight or spring drum, H".

page_text: Resting against this cam ring is the wedge shape projection, c, extending from
the lower end of a lever, I, which is pivoted to the bracket, I', secured to the front
and rear plates, B, B¹.
A spring, c¹, is also secured to this bracket, and serves to keep the end c, of the
lever continually in contact with the cam ring. To the upper end of the lever, I,
is secured a slotted horizontal arm, I", which has a limited movement laterally
governed by the forked guard, K, (fig. 1.) the downward projections on which prevent
too great a movement of the arm, and insure a proper position for the hammer with
relation to the bell and gong at each shift. This horizontal arm embraces the striking
arm and governs its lateral movements as follows:--When the striking train is
released by the time train the cam ring, H, commences its revolutions. The periphery
of this ring is laid out in the example thereof shown in figure, 3, so that every twelfth
of an inch answers to a blow of the hammer. The point, c, of the lever, I, rides on
the face of the ring near its outer edge, being retained in contact with said face by
the spring, c', as heretofore siated. While the point, c, is riding on the ring from
the notch, d, to d¹, the blow will be on the bell, F, as the striking lever is made to
retain its position opposite the same by the lever, I and its slotted arm, I", the number
of said blows being governed by the snail, C; but when the point, c, drops into the
notch, done blow will be struck on the gong, F1, as the movement of the lever, I,
shifts the position of the hammer and striking lever to the right until the hammer is.
in line with the said gong and this blow will indicate ten o'clock. The point, c, will
remain in this notch, d, for an hour when the striking train being again released one
blow will be struck on the gong counting ten, but as the cam revolves the point, c,
will ride up on space between the notch, d', and the notch, d, thus shifting the
position of the hammer, and causing the next blow to be delivered upon the bell
counting one, and making the time indicated by the two blows eleven. The notch, d³,
counts one on the gong for ten, and the succeeding space upon which the point rides,
two on the bell indicating twelve o'clock, the formation of the snail being such as to
give three blows for that hour. This is continued until twenty o'clock is reached
the space between the notches of the cam ring being increased to add an additional
stroke or unit each day. Then the notch, d³, is entered by the point, c, and two blows
struck on the gong, the point, e, will remain in this notch, d³, for an. hour. when the
striking train being again released two blows will be struck on the gong indicating
two tens or twenty o'clock, and the cam revolving causes the point, c, to ride up on
the next space causing the next blow to be delivered on the bell making the time
indicated by the three blows twenty one o'clock, and so on until the whole-twenty
four hours have been indicated, the units by strokes on the bell, and the tens by.
similar strokes on the gong.
The devices for operating the striking train independently of the time train, when it
is desired to bring the two into unison, consist of a wire, L, extending vertically from
the pawl N', of the striking rack, N, outside of the plate, B, said wire passing through
and being guided by the loop, e, attached to the plate.
By this means the pawl may be lifted, and the striking train started without
interfering with the time train.
The actuating power of the striking rack is imparted through a single toothed-
pinion, P, arranged for operation in the ordinary and well known way, see figure, 6.
The dial used with the herein before described mechanism is preferably that for.
which letters patent have previously been granted to Martin Van Buren Ethridge, in
which the dial plate is perforated with a series of twelve openings, each occupying
the place of one of the figures indicating hours on the common dial plate. Opposite.
each of these openings is placed a radial shaft carrying a rectangular or other suitably
shaped block on the faces of which are placed numerals indicating two of the twenty
four hours of the day, one of these numbers representing twelve, or a number below
These numeral blocks.
it, and the other a number between twelve and twenty four.
are properly turned to present the desired figures to view, by an arm attached to the
hour hand thimble as shown in the part of the dial broken away in Fig. 2. In this
Fig. and in Fig. 5, g, represents the hour hand, g¹, the minute hand, and,. h, an

page_text: additional hand made shorter than the others, the thimble of which is pressed on to
that of the hour hand so that the two move together, although they may be adjusted
relatively to each other. The object of this third hand is to indicate universal time
or that of the meridian of Greenwich, while the other hands indicate the local time or
that of the meridian in which the clock is located.
For example a clock in New York giving the local time of that meridian will have
the third hand set five hours ahead of the other hour hand giving the local time as is
clearly shown in figure, 2, where the local time is indicated as 18, minutes past,
23 o'clock, while the universal time, or that of Greenwich is 18 minutes past 4 o'clock.
The clock thus shows by simple inspection both the local and universal time, and
this is done simultaneously on a single circle of twelve divisions.
The radially arranged rotary spindles which compose the dial used by us as above
explained each consists of a rod carrying a block having the numerals denoting the
hours delineated on its faces and each carrying also a turnstile arrangement by means
of which in connection with an arm on the hour hand thimble the spindles are
consecutively rotated. It becomes therefore a matter of importance to construct
these spindles as cheaply as possible in order to lessen the cost of the dial plate entire.
The method of construction which we adopt therefore is as follows:-
Rods of proper length and size are first prepared, as, R, Fig. 11. This rod is
provided at or near one end with a block made of any suitable material. It may be
inade in a mold similar to that shown in Fig. 15. In this case the mold will fashion
the block plate or discs with figures more or less raised so that they may be quickly
painted or colored. The material used for molding may be of any plastic sort
provided it has adhesive qualities to enable the block to be molded firmly upon the
rod, the latter passing through the middle of it. Again in carrying out the process
hollow shells may be provided as shown in Fig. 12. They may be of rectangular or
other convenient form on whose faces the figures are to be marked. These shells may
be formed in a mold, similar to that shown in Figure, 15.
It is desirable also that the mold shall impart depressions to the outer faces of the
shell, which depressions, shall be outlined like the figures to be marked on said sides
and adapted to be filled with a material of a different color from the shell so that the
figures may be prominent.
The shells are secured to the rods by first locating the rod centrally through the
shell, and then around the rod inside of the shell we fill a cheap plastic substance
which will harden in the shell and firmly bind shell and rod together.
The turnstiles with which the spindles are to be provided, are punched from a
piece of shell metal into the form shown in Figure, 13. For this purpose an ordinary
punch and die which will give the metal the shape required will be sufficient. The
shape of this metal blank which is to form the turnstile is that of a cross having the
edges of its arms slightly tapering, if desired and having each arm provided on its
end with a projecting pin or lug, u. The centre of the cross is pierced with an
aperture, v, about the size of the rod, R, of the spindle. The metallic plate thus
shaped has its arms bent up until they meet each other, or in such a manner as to
leave a square plate having a central perforation at about right angles to the armis.
Then the pins, u, are bent out at right angles to the arm of the cross.
The turnstile is now ready to be attached to the rod which is done by passing this
rod through the aperture, v, and then soldering the turnstile firmly to the rod. The
completed spindle is shown in Figure, 11.
Figures, 9, and, 10, of the drawing show devices to be used for equalizing the
power of the main spring. Such devices are serviceable in time pieces whose motive
power is a main spring, and especially when some slight additional power is needed in
turning the blocks of the dial; preferably used in connection with this invention. In
the illustration, T, represents a main spring, and, U, one of the shafts of the
mechanism near said spring. V, is an arm having a tension spring W, secured to
it, said arm being pivoted to the clock frame by the stud, T¹, and said tension
spring, W, resting upon the shaft U. The extremity of the arm, V, is provided
with a projection X, which enters the coil of the main spring.

page_text: "
When the spring, T, is wound up it carries the arm, V. down with it thus increasing
the tension of the spring, W, on the shaft, U. As the main spring, T, unwinds or
runs down" the tension on the shaft, U, grows less, thus enabling the power of
the main spring to be equalized. The shaft, V, is here only shown by way of
illustrating a convenient mode of locating the tension device in position in a time
piece where there are several shafts adjacent to the main spring. But it is obvious
that a stud or post or projection may serve the purpose of a stop or rest, for the
spring, W, equally well with the shaft, U.
Having now particularly described and ascertained 'the nature of our said inven-
tion and in what manner the same is to be performed we declare that what we
claim is
1. The combination of the bell and gong, the two faced hammer, E, the laterally
swinging arm, E', carrying said haminer the rocker shaft, G, having the adjustable
lug, G, to which the arm, E, is pivoted, the spring or weight drum, H", wheel, H³,
secured thereto, cam ring, H, attached to the wheel, H', and notched peripherally in
the manner set forth, the pivoted lever, I having a projection, c, that engages the
cam ring and a slotted cam, I", which embraces the arm, E', and the forked
guard, K, all arranged to operate substantially as described.
2. The combination of the driving gear, C₁, the actuating pinion, C", therefor
having half as many teeth as the gear C, the hollow shaft, D, on which the
pinion, C, is mounted, the snail wheel, C, provided on its periphery with cam teeth
the striking rack, N, the single toothed pinion, P, and pawl, N³, all arranged to
operate substantially as described.
3. The combination of the bell and gong, the laterally swinging striking arm,
carrying a hammer, the rocker shaft with which the swinging arm is pivotally con-
nected the spring or weight drum, the gear wheel secured to the drum, the peripherally
notched cam ring attached to said gear wheel, the pivoted lever having a projection
that engages the cam ring and a slotted arm that embraces the striking arm, and the
mechanisin described for setting in motion the striking devices, substantially as
described.
4. The combination of the snail wheel, C, constructed as shown, the driving
gear, C, said snail wheel and driving gear being connected and placed on a stud, a,
the pinion, C, having half as many teeth as the gear, C₁, the striking rack, N,
pawl, N¹ single toothed pinion, P, the bell and gong, the striking arm carrying the
hammer, the cam ring, spring or weight drum, and the spring actuated lever, provided
with a slotted arm, all arranged to operate substantially as described.
5. The combination of the bell and gong, the laterally swinging striking arm, El,
carrying a hammer, E, having faces, b, and, b, the rocker shaft, G, having the
adjustable lug, G', to which the arm, E1, is pivoted, the drum, H¹¹, wheel, H', secured
thereto, cam ring, H, attached to the wheel, H', and notched peripherally as shown,
the bracket, I', lever, I, pivoted to said bracket and having projection, c, and slotted
arm, I", the spring e', guard, K, snail wheel, C, and gears, C³, and, (1, all arranged
and operated as set forth.
6. In a time piece the combination with the main spring and an adjacent shaft, of
a pivoted arm provided with a projection engaging said main spring, and with
a spring arm hearing upon said shaft, substantially as
and for the purposes
specified.
7. In a twenty four hour clock, a dial for simultaneously indicating local and
universal time, composed of a series of individually shifting numeral blocks which
expose their faces in a single dodecimally graduated circle, in combination with two
local time pointers, and one universal time pointer substantially as described.
8. The herein described method of making spindles for time piece dials which
consists in providing rods with plastic numeral blocks molded thereon, and also with
turnstiles punched from sheet metal bent into the required shape, and attached thereto,
substantially as described.
9. The herein described method of making spindles for time piece dials, which

page_text: consists in molding upon a rod plastic blocks having raised figures on the surface of
said blocks substantially as and for the purpose described.
10. The hereindescribed method of providing rods with numeral blocks for use as
spindles in timepiece dials, which consists in making shells on whose outer surface
the numerals may be marked, and attaching these shells to rods, by a plastic filling,
substantially as described.
11. The hereindescribed method of providing rods with numeral blocks for use as
spindles in time piece dials, which consists in forming shells having numeral depres-
sions on the exterior surface; filling said depressions with a differently colored
substance from shell and then attaching the shell to the rod by inserting a plastic
substance within said shell about the rod, substantially as described.
12. The hereindescribed method of providing rods with numeral blocks for use as
spindles in time piece dials, which consists in molding shells and attaching these
shells to rods by locating them about the rod and inserting a plastic filling substan-
tially as described.