U.S. patent number 3,704,583 [Application Number 05/222,260] was granted by the patent office on 1972-12-05 for date indicating mechanism for watches.
This patent grant is currently assigned to Societe Suisse pour l'Industrie Horlogere SA. Invention is credited to Peter Dome.
United States Patent |
3,704,583 |
Dome |
December 5, 1972 |
DATE INDICATING MECHANISM FOR WATCHES
Abstract
A date indicating mechanism for watches, of the type having a
rotatable ring carrying date numbers on one side, equidistantly
spaced over the circumference thereof, and means for periodically
moving the ring past an inspection window for the date numbers, the
improvement comprising drive means for the ring carrying the date
numbers, said drive means consisting of a rotatable disk carrying
pins meshing with slits provided on one edge of the date number
ring and with engagement means on the periphery of a substantially
circular cam driven by the gear train of the watch.
Inventors: |
Dome; Peter (Brugg bei Biel,
CH) |
Assignee: |
Societe Suisse pour l'Industrie
Horlogere SA (Geneve, CH)
|
Family
ID: |
4217069 |
Appl.
No.: |
05/222,260 |
Filed: |
January 31, 1972 |
Foreign Application Priority Data
Current U.S.
Class: |
368/37;
968/180 |
Current CPC
Class: |
G04B
19/24 (20130101); G04C 17/0058 (20130101); G04B
19/25353 (20130101) |
Current International
Class: |
G04B
19/00 (20060101); G04B 19/253 (20060101); G04b
019/24 () |
Field of
Search: |
;58/4R,4A,5,58 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
172,591 |
|
Nov 1921 |
|
GB |
|
1,042,477 |
|
Oct 1958 |
|
DT |
|
Primary Examiner: Miller, Jr.; George H.
Claims
I claim:
1. In a date indicating mechanism for watches, of the type having a
rotatable date number ring carrying on one side n date numbers
equidistantly spaced over the entire circumference of the ring and
means for periodically driving the ring through an angular distance
corresponding to 360.degree./n past an inspection window permitting
the date numbers on the ring to be individually and successively
observed, the improvement of said drive means comprising a series
of n slits equidistantly spaced around the circumference of the
rotatable date number ring, said slits being open at one edge of
the date number ring and having parallel longitudinal edges, a
longitudinal axis oriented toward the center of the date number
ring, and a radial length substantially corresponding to half the
distance between the two points of intersection between the two
opposed longitudinal edges of two adjacent ones of said slits and
the edge of the date number ring containing the open ends of said
slits;
a disk located in a plane extending parallel to the plane of the
date number ring and rotatably mounted on a shaft centered
substantially at right angles to the edge of the date number ring
containing the open ends of said slits; said disk carrying four
equidistantly angularly spaced pins each spaced from the axis of
said shaft of said disk by a distance substantially corresponding
to half the distance between the two points of intersection of the
two adjacent longitudinal edges of two neighboring ones of said
slits in the date number ring with the edge of the latter
containing the open ends of said slits, the width of said pins
being substantially equal to that of said slits; said pins, located
in diametrically opposed positions on said disk with respect to the
axis of rotation thereof, having a projecting portion of a length
at least greater than the distance between the adjacent surfaces of
said date number ring and said disk, the other two of said pins
having a projecting portion of a length smaller than said
distance;
a rotatable substantially circular cam located in a plane extending
parallel to the plane of said date number ring and having an
operative profile composed of a first and a second portion, said
first portion extending in a circular direction around the axis of
rotation of said rotatable cam and being designed for locking said
date number ring in one of its n angular positions, the axis of
rotation of said rotatable cam being positioned so that said first
portion of the rotatable cam will engage two neighboring ones of
said pins on said disk;
said second portion of said rotatable cam being designed for moving
said date number ring from a given angular position to the next one
and including a radial projection having a width corresponding at
most to the distance between two neighboring ones of said pins, and
two recesses arranged one on each side of the radial projection and
having a width at least corresponding to that of said pins, and
a kinematic chain for moving said rotatable cam by one revolution
each 24 hours from the gear train of the watch.
2. A date indicating mechanism as claimed in claim 1, wherein said
disk and the two shorter pins mounted thereon are made of
non-magnetic material whereas the two longer pins are made of
magnetizable material and are secured with one of their ends in
holes extending through the thickness of said disk so as to
terminate with said ends flush with the surface of said disk
opposed to the surface of said disk carrying said projecting
portions of said pins, a magnetizable armature is located in front
of said surface of said disk opposed to the surface of said disk
carrying said projecting portions of said pins, said date number
ring is made of magnetizable material, and a permanent magnet is
arranged between said armature and a region of said date number
ring near the region thereof where said magnetizable pins engage
said slits in said date number ring, so that at least one of said
magnetizable pins is permanently maintained in engagement with said
date number ring due to the magnetic attraction exerted
therebetween, irrespective of the angular position occupied by said
pin carrying disk.
Description
This invention relates to a date indicating mechanism for watches,
of the type having a rotatable ring carrying on one side n date
numbers equidistantly spaced over the entire circumference of the
ring and means for periodically the ring through an angular
distance corresponding to 360.degree./n past an inspection window
permitting the date numbers on the ring to be individually and
successively observed.
Many date indicating mechanisms of this type are already known,
they being designed mainly for mechanically operated watches in
which the date numbers carried by a movable member appear
successively in the inspection window. The position of the movable
member is generally determined by a spring locking member which
successively engages between the teeth of a toothed edge provided
on the movable member as the latter is rotated step by step. During
the daily operation of the movable member the driving member must
therefore overcome the spring force of the locking member to
disengage it from the toothed edge. The power required for this
purpose is derived directly from the wheel train of the watch and
thus must be supplied by the watch drive spring.
If this slight loss of power may be tolerated in this type of watch
in which the drive power is supplied by a drive spring which is
either manually or automatically wound up from time to time, it is
different with electromechanically and electronically driven wrist
watches in which this loss of power causes a considerable reduction
of the useful life of the supply battery. Further, since there is
very little space available in such wrist watches supply batteries
must necessarily be small and consequently power consumption must
be reduced to a minimum to permit the produced watches to be sold
and to compete on the market with other watches, particularly
mechanically driven watches/adapted to be wound up
automatically.
This is certainly one of the reasons why the conventional date
indicating mechanisms, although they have already been tested for
many years, have not been generally adopted in electromechanically
or electronically driven wrist watches.
As is known, these watches are all provided with an electric
circuit generating current pulses each carrying a minute quantity
of power and designed either to control a mechanical regulating
device or drive a motor. By adding a date indicating mechanism to
such watches, the regulating device or motor must also drive this
mechanism in addition to the time indicating means and then this
mechanism constitutes a frequent source of faults caused mainly by
the spring locking member.
To eliminate this drawback a date indicating mechanism has already
been proposed in which a Maltese cross wheel is rotatably mounted
on an axle extending perpendicularly to the plane of the date
number ring and is driven by the hour hand wheel through a drive
wheel making one complete revolution every 24 hours. This Maltese
cross wheel is provided with a pin engaging in slits provided on
the date number ring, and with a circle segment member cooperating
with concave surfaces provided on the teeth located between said
slits. Thus the segment member secures the date number ring in the
required position.
In this form of construction positioning of the date number ring is
effected by engagement by two concentric surfaces carried by two
movable members, i.e., the Maltese cross wheel and the date number
ring, which are eccentrically mounted with,respect to each other.
As the date number ring is generally not supported for pivotal
movement about a shaft its center of rotation is usually determined
by a circular bearing surface provided on the bearing plate of the
watch so as to engage the date number ring.
This manner of providing for rotary movement of the date number
ring of course makes it necessary to leave a certain amount of play
between the date number ring and its centering bearing surface on
the bearing plate of the watch to avoid seizing. This is the reason
why in this form of construction the Maltese cross is supported on
a rocker lever urged by a spring against the date number ring to
eliminate the play and ensure intimate engagement between the two
concentric positioning surfaces. By pressing these surfaces
together considerable friction is produced during rotation of the
Maltese cross wheel. Consequently, although this form of
construction has permitted to eliminate the source of faults caused
by the locking member in the conventional construction, this
proposed new structure has another even greater drawback which is
the relatively high friction produced between the positioning
surfaces.
It is the object of the present invention to eliminate the
above-mentioned drawbacks of the hitherto proposed constructions.
This object is achieved according to the invention by providing a
date indicating mechanism for watches, in which the drive means
comprise:
a series of n slits equidistantly spaced around the circumference
of a date
number ring, said slits being open at one edge of the date number
ring and having parallel longitudinal edges, a longitudinal axis
oriented toward the center of the date number ring, and a radial
length substantially corresponding to half the distance between the
two points of intersection between the two opposed longitudinal
edges of two adjacent ones of said slits and the edge of the date
number ring containing the open ends of said slits;
a disk located in a plane extending parallel to the plane of the
date number ring and rotatably mounted on a shaft centered
substantially at right angles to the edge of the date number ring
containing the open ends of said slits, said disk carrying four
equidistantly angularly spaced pins each spaced from the axis of
said shaft by a distance substantially corresponding to half the
distance between the two points of intersection of the two adjacent
longitudinal edges of two neighboring ones of said slits in the
date number ring with the edge of the latter containing the open
ends of said slits, the width of said pins being substantially
equal to that of said slits and two of said pins, located in
diametrically opposed positions on said disk with respect to the
axis of rotation thereof, having a projecting portion of a length
at least greater than the distance between the adjacent surfaces of
said date number ring and said disk, the other two of said pins
having a projecting portion of a length smaller than said distance;
a rotatable cam located in a plane extending parallel to the plane
of the date number ring and having an operative profile composed of
a first and a second portion, said first portion extending in a
circular direction around the axis of rotation of said rotatable
cam and being designed for locking the date number ring in one of
its n angular positions, the axis of rotation of said rotatable cam
being positioned so that said first portion of the rotatable cam
will engage two neighboring ones of said pins on said disk, said
second portion of the rotatable cam being designed for moving the
date number ring from a given angular position to the next one and
including a radial projection having a width corresponding at most
to the distance between two neighboring ones of said pins, and two
recesses arranged one on each side of the radial projection and
having a width at least corresponding to that of said pins, and a
kinematic chain for moving said rotatable cam by one revolution
each 24 hours from the gear train of the watch.
A preferred embodiment of the invention will now be described by
way of example and with preference to the accompanying drawings, in
which:
FIG. 1 is a top plan view of a date indicating mechanism according
to the present invention;
FIG. 2 is a section taken on the line II--II of FIG. 1;
FIGS. 3 to 8 are part views of FIG. 1, showing different positions
of the date number ring, pin supporting disk and rotatable cam,
and
FIG. 9 is a part view showing another embodiment of the date number
ring, pin supporting disk and rotatable cam.
The mechanism shown in the drawings is designed to produce at about
24.00 hours of each day a substitution of the indication of the
date number appearing in an inspection window G provided in a dial
C of a watch.
As shown in FIG. 1, this mechanism comprises a date number ring 1
composed of two portions, namely a first annular portion 1A
carrying on its upper face the numbers 1 through 31 corresponding
to the number of days in a month, and a second cylindrical portion
1B supporting the date number ring 1 on a seat 2A provided on a
bearing plate 2 of the watch, the seat 2A having an annular shape
and extending symmetrically around a shaft 3 carrying the hour hand
of the watch the rest of which is not shown in the drawings as it
does not relate to the present invention.
Along its inner edge the date number ring 1 is provided with 31
equidistantly spaced slits 4 each having two parallel longitudinal
edges and an axis of symmetry oriented toward the center of the
date number ring 1. The radial length of each slit 4 is slightly
greater than half the distance between the ends a and b of the
opposed longitudinal edges of two neighboring slits 4.
The illustrated date indicating mechanism further comprises a disk
5 rotatably mounted on a shaft 6 whose longitudinal axis extends
substantially at right angles relative to a point on the inner edge
of the date number ring 1, the shaft 6 being secured in the bearing
plate 2. The disk 5 carries four pins 7A, 7B, 8A and 8B having a
diameter substantially corresponding to the width of the slits 4 in
the date number ring 1 and symmetrically arranged in opposed pairs
on the disk 5 with respect to the shaft 6.
The pins 7A, 7B, 8A and 8B are secured in the disk 5 in the manner
shown in FIG. 2 with reference to the pin 7B and their lower ends
are flush with the bottom surface of the disk 5. The distance
between the axes of symmetry of the pins 7A and 7B and 8A and 8B,
respectively, substantially corresponds to the distance between the
longitudinal axes of symmetry between two neighboring slits 4 as
measured at the level of the inner edge of the date number ring
1.
Finally, the length of the projecting portion of the two pins 8A
and 8B is greater than the distance between the top of the disk 5
and the bottom of the annular portion 1A of the date number ring 1
whereas the length of the projecting portion of the two pins 7A and
7B is smaller than this distance, as seen in FIG. 2. Therefore,
when the disk 5 is rotated around the axis of the shaft 6, for
example, in clockwise direction, the pins 8A and 8B will mesh with
the teeth 1C between the slits 4 in the annular portion 1A of the
date number ring 1 whereas the pins 7A and 7B will pass below the
lower surface of this portion 1A without touching it.
In the illustrated embodiment the two pins 8A and 8B are made of
ferromagnetic material as is the entire date number ring 1 whereas
the disk 5 and the pins 7A and 7B are preferably made of
non-magnetic material. The pins 8A and 8B as well as the sector of
the date number ring 1, delimited roughly by two straight radial
lines tangent to the disk 5 in diametrically opposed positions of
the latter, form part of a magnetic circuit including a permanent
magnet 9, secured to the bearing plate 2 adjacent the cylindrical
skirt 1B of the date number ring 1, and an L-shaped magnetizable
armature 10 engaging the magnet 9 with its shorter leg and the
bearing plate 2 with its longer leg which rests on the bearing
plate 2 and extends in part below the disk 5 and thus faces the
lower ends of the pins 8A and 8B irrespective of the angular
position of the disk 5 so that the air gap between these pins and
the armature 10 will remain always the same. The purpose of this
magnetic circuit will appear from the following description.
The illustrated date indicating mechanism further comprises a
rotatable substantially circular cam 11 firmly secured to a gear
wheel 12 and rotatably mounted on a shaft 13 extending upwardly
from the mounting plate 2 in a position such that the plane passing
through the longitudinal axes of the shafts 13 and 6 forms a
dihedral angle with the plane passing through the longitudinal axis
of the shaft 6 and that of the shaft 3.
The gear wheel 12 is driven by a gear wheel 14 mounted on the shaft
3 and driven directly by a gear wheel 15 of the hour hand of the
watch. The diameter of the gear wheel 12 and that of the gear wheel
14 are so chosen that the circular cam 11 will make one complete
revolution every 24 hours.
As seen in FIG. 1, the circular cam 11 engages with its circular
edge portion two pins on the disk 5, which in the position of the
disk 5 shown in FIG. 1 are the pins 7A and 8A, so that the disk 5
cannot move angularly in either direction of rotation. In this
position of the disk 5 the pins 8A and 8B engage in two slits 4 in
the date number ring 1 and as the diameter of these pins
substantially corresponds to the width of the slits 4, they ensure
perfect locking of the date number ring 1 in its angular position
provided that the disk 5 itself remains locked by the circular cam
11.
However, to ensure such locking the dimensions of the slits 4 in
the date number ring 1, the angular spacing of the slits 4, the
dimensions of the pins 8A and 8B as well as their positions on the
disk 5 and the position of the disk 5 on the bearing plate 2 must
be very accurate. Such accurate dimensions can be achieved in
practice but in the illustrated embodiment it is not indispensable,
particularly in view of the action exerted by the permanent magnet
9 and the magnetic circuit in which this magnet is incorporated and
which has been described above.
In fact, supposing that the width of the slits 4 is slightly
greater than the diameter of the pins 8A and 8B, in which case
there would be some play between the pins and the edges of the
slits so that the date number ring 1 could perform a slight angular
movement, this play is compensated in the illustrated embodiment by
the action of the magnetic circuit since the pins 8A and 8B as well
as the date number ring 1 are traversed by magnetic flux and
consequently at least one of these pins is magnetically attracted
toward one of the longitudinal edges of the slit in which it is
located and thus firmly engages that edge of the slit.
As shown in FIG. 1, the periphery of the circular cam 1 is not
completely circular. In fact, a length of about 1/10 of the
circumference of the cam 1 is occupied by two recesses 16 and 17
and a projection 18 located between the recesses 16 and 17. The
projection 18 has a substantially trapezoidal shape, its width at
the top is slightly smaller than the distance between two adjacent
ones of the pins 7A, 8A, 7B and 8B on the disk 5 and its length is
such that it does not engage the shaft 6, for example, during
angular movement of the circular cam 11 from the position indicated
in FIG. 4 to that shown in FIG. 6.
The recesses 16 and 17 each have an approximately semicircular
shape, a width slightly greater than the diameter of the pins 7A,
7B, 8A and 8B and a depth slightly greater than half the diameter
of the pins. The circular cam 11, in fact, does not only serve the
purpose of locking the disk 5 as described above, but also serves
for periodically moving the disk 5 once during each revolution of
the circular cam 11, through an angular distance of 180.degree.
which corresponds to a movement of the date number ring 1 through
an angular distance of 360.degree. /31 , i.e., the distance
required to replace a date number appearing in the inspection
window G of the dial C by the following date number, as will be
explaine hereafter by reference to FIG. 1 and FIGS. 3 through 8 of
the drawings.
In the illustrated embodiment the circular cam 11 is driven by the
gear wheel 14 in an anticlockwise direction. As the circular cam 11
engages with its circular peripheral portion the pins 8A and 8B,the
disk 5 and consequently the date number ring 1 are locked in their
positions indicated in FIG. 1. This condition is maintained until
the projection 18 engages the pin 7A, as shown in FIG. 3, for
thereafter the disk 5 in moved in a clockwise direction by the
projection 18, as seen in FIG. 4. As the disk 5 further has its
pins 8A and 8B meshing with the teeth 1C of the date number ring 1,
angular movement of the disk 5 will produce a corresponding angular
movement of the date number ring 1, particularly through the action
of the pin 8A which moves angularly in a circular path and
simultaneously penetrates more deeply into the interior of the slit
4 in which it is located (FIG. 1), and exerting a pressure on the
edge of this slit 4 which in the drawing is located on the
right.
If the speed of rotation of the circular cam 11 is constant, the
angular movement of the date number ring 1 follows a sinusoidal
course. Thus the speed of angular movement of the date number ring
1 is relatively small when the projection 18 begins to exert its
pressure on the pin 7A, as shown in FIG. 3, and gradually increases
as the projection 18 approaches its position shown in FIG. 5, in
which position the longitudinal axis of the projection 18 is in
alignment with the plane passing through the axes of simmetry of
the shaft 13 and 6 and consequently the pin 8A occupies its
position located most closely to the bottom of the slit 4 in which
it is engaged. Thus the speed of angular movement of the date
number ring 1 is greatest when this ring passes through the
position shown in FIG. 5 and thereafter it decreases until it is
reduced to zero.
Once the circular cam 11 has passed beyond the position shown in
FIG. 5 there will come a moment when the pin 7A has moved
sufficiently away from the projection 18 so that the latter can no
longer shift the pin 7A. However, movement of the disk 5 continues
due to the pressure exerted by the edge of the recess 17 on the pin
8B located in this recess when the pin 7A separates from the
projection 18, as shown in FIGS. 6 and 7. The movement of the disk
5 does not stop until the pin 8B is in the position occupied by the
pin 8A in FIG. 1 or until the pin 8A is in the position occupied by
the pin 8B in FIG. 1.
The dimensions of the circular cam 11, projection 18, recesses 16
and 17 and the transmission ratio of the gear wheels 12 and 14 are
such that the time required for moving the disk 5 through an
angular distance of 180.degree. is about 1 to 2 hours. Consequently
the time required for moving the date number ring 1 through an
angular distance of 360.degree./31, i.e., the time required for
replacing the date number appearing in the inspection window G by
the following date number, is likewise about 1 to 2 hours.
It should be noted that with the described date indicating
mechanism the date number ring 1 will remain locked not only when
it is kept in its rest position by the pair of pins 8A and 8B
engaging in two adjacent slits 4 and by the pair of pins 8A and 7A
engaged by the circular peripheral portion of the cam 11, but also
during the angular movement of the date number ring 1 imparted
thereto by the pin 8A or 8B on the disk 5, the projection 18 on the
circular cam 11 or the recess 16 or 17 in which engage the pins of
the disk 5, the angular position of the circular cam 11 being
controlled by the gear train of the watch.
The previously mentioned reciprocal magnetic attraction between the
pins 8A and 8B, on the one hand, and the date number ring 1, on the
other, occurs irrespective of the angular position of the disk 5,
i.e., irrespective of the degree of penetration of the pin 8A or 8B
into one of the slits 4 in the date number ring 1. Therefore, this
pin will always be in material engagement with a portion of one
edge of the slit so as to eliminate the influence of the play which
may exist between the pins and the teeth of the date number ring
1.
It should further be noted that all members of the described drive
mechanism have a symmetrical configuration so that this drive
mechanism can be used both for moving the date number ring 1 in a
clockwise direction, as described above, and for moving the date
number ring in an anticlockwise direction, particularly when it is
desired to change the date appearing in the inspection window G by
actuation from the outside of the watch, for example, by means of
the time adjusting device of the watch.
All elements of the described mechanism have a particularly simple
structure so that they can be easily and inexpensively produced and
mounted. Further the operation of this mechanism is of great
simplicity and this guarantees good working and small wear of the
mechanism over a long period of time.
Finally, as the date number ring 1 has a very simple geometric
serrated configuration formed by the series of teeth 1C defined by
the slits 4 with their open ends on the inner edge of the date
number ring, and as the drive pins 7A, 7B, 8A, and 8B on the disk 5
have a shape which can be easily produced, the play in the angular
displacement of the circular cam 11 may be very small. Further, due
to the disposition of the disk 5 carrying the pins 7A, 7B, 8A and
8B, a radial play which may exist in the positioning of the date
number ring 1 will produce only a very small angular play of the
date number ring.
It is to be understood that the invention is not limited to the
described and illustrated embodiment and that numerous changes and
modifications may be made therein without departing from the scope
of the invention. In particular, the described date indicating
mechanism could very well be produced without a permanent magnet 9,
but in such a mechanism evidently the play which may exist between
the pins 7A, 7B, 8A, 8B and the teeth 1C and the date number ring 1
cannot be taken up.
Further, it would also be possible to provide a date indicating
mechanism in which the date number ring 1 has slits 4 located with
their open ends on the outer edge of the date number ring 1, as
shown in FIG. 9. In this case the disk 5 and the rotatable circular
cam 11 are mounted on shafts extending with their axes at right
angles to the outside edge of the date number ring 1 in a plane
forming a dihedral angle of 45.degree. with the plane passing
through the axis of rotation of the disk 5 and the axis of symmetry
of the date number ring. 1.
The date indicating mechanism of the present invention can be used
for mechanically operated watches as well as electromechanically or
electronically operated watches.
* * * * *