Note: Descriptions are shown in the official language in which they were submitted.
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ELECTRONIC TIMEPIECE
BACKGROUND OF THE INVENTION
The invention is generally directed to an Electronic
Timepiece which provides for continuous hand movement and in
particular to an analog electronic timepiece which provides
continuous and smooth hand movement from a disccete timepiece
movement.
Reference will now be made to the accompanying
drawings, in which:
Fig. 1 is a partial sectional view of a conventional
electronic timepiece;
Fig. 2 is a sectional view of an electronic timepiece
in accordance with a first embodiment of the invention;
E'ig. 3 is a plan view of the electronic timepiece of
Fig. 2;
Fig. 4 is a graphical representation of the
relationship between the wrapping angle of the hairspring and
the restoring force of the hairspring:
Fi~. 5 is a graphical representation of the
relationship between the angular velocity of the viscous rotor
and the load torque thereon:
Fig. 6 is a plan view of a portion of an electronic
timepiece in accordance with a second embodiment of the
invention;
Fig. 7 is a plan view of a poction of an electronic
timepiece in accordance with a third embodiment of the invention;
t~t t~6~
Fig. ~ is a plan view of an electronic timepiece in
accordance with a fourth embodiment of the invention;
Fig. 9 is a elan view of an electronic timepiece
constructed in accordance with a fifth embodiment of the
nvention:
Fig. lO is a sectional view of an electronic timepiece
in accordance with a sixth embodiment of the invention:
Fig. 11 is a partial sectional view of an electronic
timepiece utilizing a magnetic escapement in accordance with a
seventh embodiment of the invention;
Fig. 12 is a eartial sectional view of an electronic
timepiece utilizing a magnetic escapement in accordance with an
eighth embodiment of the invention;
Fig. 13 i8 an enlarged partially cut away perspective
view of the magnetic escapement of the timepiece of Fig. 11;
Fig. 14 is an enlacged partially cut away perspective
view of the magnetic escapement of the timepiece of Fig. 12:
Fig. 15 is an enlarged sectional view of the viscous
rotor and viscous fluid assembly in an embodiment of the
invention:
Fig. 16 is an enlarged partially cut away sectional
view of the viscous cotor and viscous fluid assembly in
accordance with another embodiment of the invention:
Fig. 17 is a sectional view of an electronic timepiece
constructed in accordance with a ninth embodiment of the
invention:
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1 31 ~ 364
Fig. 18 is an enlarged sectional view of the hairspring
assembly in an embodiment of the invention;
Fig. 19 is a partially exploded, cut away perspective
view of an electronic timepiece with a removable control
mechanism in an embodiment of the invention; and
Fig. 20 is a functional block diagram of an electronic
timepiece in an embodiment of the invention.
Reference is made to Fig. 1 wherein a timepiece,
generally indicated as 100, constructed in accordance with
Japanese Patent Publication No. 56-47512 is shown. Timepiece
100, which is only shown in partial relevant section, includes a
drive train 101, shown schematically, power gear 102 and power
pinion 109 supported by pivots 105 and 119 between main plate
117 and gear train bridge 123. Pivot 119 is supported in pivot
support 121 on main plate 117, which is secured in place by
screw llZ.
Pinion 109 drives third gear 122 which is supported by
pivots 106. Third pinion 110, which is fixed to third gear 122,
in turn drives minute hand gear 108. To produce a continuous
motion of the second hand or sweep second hand, power pinion 109
drives driving magnet 115. Driving magnet 115 is supported by
magnet support 114, which is directly coupled to power pinion
109. A first following magnet 116 is enclosed by a viscous
fluid 113, thereby producing viscous resistance to rotation.
First following magnet 116 and viscous fluid 113 are supported
by support plate 120 on main plate 117. First following magnet
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131 1364
116 is deiven by the attcactive force of driving magnet 115. A
second following magnet 118 is driven by first following magnet
116. Second following magnet 118 is coupled to second hand
display shaft 111. In this way, the conventional ana1og
13113~4
electronic timepiece with a discrete time keeping movement
provides for continuous hand movement.
In this type of conventional timepiece, the portion
of the timepiece which stores the rotary energy and the
portion which gradually releases the rotary energy is
formed as a single member, i.e. the driving magnet and
following magnets. This results in several problems. If
the size or configuration of the following magnet is
changed to vary the amount of energy which can be stored,
the viscous resistance to the viscous fluid tends to
change, thereby resulting in jerky, non-smooth hand
movement. On the other hand, if the size of the gap
between the following magnet and main plate i~ changed,
the magnitude of the magnetic attractive force tends to
vary.
Variations in the phase deviation, i.e. the angle
between the driving magnet and the first following magnet
on the one hand and the angle between the first following
magnet and the second following magnet on the other hand,
cause the attractive or repulsive forces along the axial
direction of the magnets to change. This results in the
magnets, and particularly the first following magnet shown
in Fig. 1, moving upward or downward within the limits of
the clearance providing by the viscous fluid. The
movement of the first following
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magnet within the cavity of viscous fluid changes the
viscous resistance to movement of the first following
magnet. It also changes the orientation of the magnet
which causes changes in friction due to the thrust force
and the direct friction of the edges of the first
following magnet against the main plate. A non-uniformity
of rotation is the result.
In addition, the conventional timepiece of the type
shown in Fig. 1 has a multiple step structure, which makes
it difficult
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to reduce the thic~ness of the timepiece, and also results in
there not being enough of a span between the bearings. Thel
axes for supporting the hand are unstably supported and thel
hand tends to become undesirably tilted during operation.
Another problem with the conventional structure is the~
sine wave relationship between the ma~netic attractive force
and the rotational angle. As a result, when the angle between
the driving magnet, and the first following magnet or the first-
following magnet and the second following magnet is greater
than 90, the magnitude of the restoring force is reduced for
increased angular deviation and the magnet system does not
properly function to control the rotation of the followillg magllet.
When the angle between the magnets is about either 0 or 90,
the restoring force barely changes as the angle between the
magnets changes so that responsive speed control is not achieved.
l'his is seen by examination of a sine curve at 0 or 90 where
~he rate o~ change in amplitude per change in angle is slnall.
A~ a result, when the angle between the magnets i8 at 0 or
90, due to Pluctuations or changes in the viscous load, the
speéd is not effectively controlled.
In a real world situation there are many forces which
result in fluctuations in the magnet attractive force and
viscous load or fluctuations due to the dimensional accuracy and
uneven magnetization. These stresses to the system may result
in angles between the driving magnet and the following magnet
being occasionally greater than 180. In these situations the
following magnet not only fails to correctly control the speed,
but it in fact rotates in the opposite direction. Thus an in-
appropriate time is displayed.
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131 1364 l
Further, because the magnets are rotated in the ~imepiece,
there is magnetic interference between~ the magnets and the
stepping motor. As a result, tlle layout of the componentsl
is severely restricted. In addition, viscous fluids havingi
a very high viscosity is required to o~tain the high viscous¦
resistance at low rotary speed required by the conventional 11
arrangement which requires as many rotary magnet assemblies¦
as there are hands. This increases the cost and di~ficulty !
of assembling the timepiece.
Accordingly, there is a need for an improved timepiecel
wllich converts the discrete movement of the timekeeping circuitry !
and step motor to continuous movement of the hand whicll isl
reliable, efEective, relatively insensitive to in~ernal an~,
external stresses! compact, easy to repair and adaptable to
a thin timepiece.
SUMMA~
The disclosure is generally directed to an electronic
timepiece for providing continuous rotation of a hand in response
to a discrete driving rotation. The timepiece includes an energy
storage mechanism coupled to the discrete driving rotation ~or
converting the discrete driving rotation to stored energy.
control mechanism continuously releases the stored rotation~l
energy as continuous rotation. A linkage mechanism coupled
between the energy stora,ge mechanism and control mechallism
transmits the continuous rotation from the energy storac3e
mechanism to the control mechanism. The hand is coupled to
the linkage mechanism for providing a continous sweep hand
movement.
¦ It is an object of the disclosure to provide
30 il an improved electronic timepiece which converts a steppe-l
¦¦ timepiece drive mechanism to continuous sweeping hand movelllent.
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1 1311364 ` 'I
further object of the disclosure is to provide an improved
timepiece for converting discrete driving rotary movement of~
a timepiece to a continuous sweepina hand movement by use of~
an energy storage system separately formed from a control
mechanism for producing substantially constant speed rotary
¦motion.
l Another object of the disclosure is to provide an improved
¦analog-type electronic timepiece in which a stepping motor whicll
¦is intermittently rotated by signals provided from reference'
¦signals drives a display mechanism to display time incorporating
a storage mechanism for storing the rotary energy of the stepping
l motor and a control mechanism for gradually releasing the rotary~
¦ energy in the form of smooth rotary motion where both the storage
mechanism and control mechanism are separately provided in the
electronic timepiece.
¦ A further object of the disclosureis to provide ~n improved
¦analog-type electronic timepiece in which a stepping motor which
lis intermittently rotated by signals divided from reference
¦signals drives a display mechanism in a continuous sweeping
¦manner utilizing a hairspring to store the rotary energy Oe
¦the stepping motor and a rotor in a viscous fluid to contro]
¦the release of the energy in a substantially continuous manner.
St~ill another object of the disclosure is to provide an
analog-type electronic timepiece in which a stepping motor which
is intermittently rotated by signals divided from reference
signals drives a display mechanism in a sweeping continous manneL-
utilizing a magnetic escapement as the control means and a firs~
following magnet as the storage mechanism to convert the stepwise
! rotation of the step motor to continous sweeping motion of a
Ihand.
,1 - 8 -
t 3t t 36~
Specific embodiments of the invention will now be described.l
Reference is first made to Fig. 20 wherein a timepiecel
200 embodying the invention is depicted.
Timepiece 200 includes a quartz crystal oscillator 201, a
timepiece circuit 202 which divides the reEerence signal Erom
oscillator 201 and generates discrete driving signals Eor driving
transducer 203. Transducer 203 is a stepping motor in a
preferred embodiment. A storage mechanism 204 saves the rotary
energy generated by transducer 203. Control mechanism 206
gradually releases the stored energy in the form of smooth rotaryl
motion. The storage mechanism is connected to the control¦
mecllanism through variable speed mechanism 205. Varial~le spce(l !
mechanism 205 drives display mechanism 207.
In a structure of the type shown in Fig. 20 the storage
mechanism is separated from the control mechanism. As a result,
a timepiec~: embodying the present invention
ca~ be con.tructed wi~h desirable characteristics such as size;
and thickn~s characteristics. In addition, the separation
of the storage mechanism and control mechanism simplifies repair
of th~ timQ~iece ~er assembly.
Reference is next made to Figs. 2 and 3 wherein an electronic
timepiece, generally indicated as 210 constructed in accordance
with a~ fi~-st embodiment of the invention is depicted. Fig.
2 is a se~tional view of timepiece 210 and Fig. 3 is a plan
view of tinepiece 210. Timepiece 210 includes a coil 1 wound
around around core 2 having a stator 4. Stator 4 drives rotor
¦~s in a stepwise Eashion. Sixth pinion 6 which engages wi~l,
irotor 5 dlives fifth gear 7 which engages with EiE~Il pinion
¦18. Fifth pinion 8 drives hairspring gear 9, whicll is couple(l
l'to one end oE hairspring 10. The other end of hairspring 1(~
.
!¦ _ g _
131 1364
ll
is coupled to hairspring pinion 11. I{airsping pinion 11 engages¦
with idler gear 12, which in turn engages with viscous rotor
pinion 13. Viscous rotor pinion 13 is fixed to viscous rotor
14, which is enclosed within cavity 19 and surroùnded by viscous
fluid 17. In a preferred embodiment, viscous fluid 17 is al
silicone oil. Hand 16 is coupled to fourth gear 15, which in¦
~urn engages with viscous rotor pinion 13 through fourth idler
gear 12, and is rotated at a speed ratio corresponding to the
number of gear teeth. Rotor 5 sixth pinion 6, fif th pilliOIl
U, fifth gear 7, a winding stem 23 and idler gear 12 are supported~
!~ between a gear train bridge 22 and a main plate 21. viscous
rotor pinion 13 and viscous rotor 14 are supported for rotation
between gear train bridge 22 and a cavity member 9a. Coil 1
is fixed to main plate 21 by screw 3.
Electrcnic timepiece 210 uses hairspring 10 as the storage
meaJ;3 and ~!:iliæes viscous rotor 14, with the viscous load oE
vl~cou~ ~lUid 17, a~ the control mechanism. Tlle gear train,
as describe~l above is provided between main plate 21 and gear
train bridg~ 22. Coil 1 generates a magnetic field for driving
rotor 5 tl-~ugh stator 4 and magnetic core 2. Rotor 5 drives
hairspring gear 9 through a reduction gear train including sixtll
pinion 6, fifth gear 7 and fifth pinion 8. The reduction ra~e;
"a" is represented as ~ 7 - ~ where rotor 5 rotates througl
an angle o~ for each step, the generated torque is TMgmlll,
and the spring constant of the hairspring is Kgmm/. On the
other hand, the motion of hairspring pinion 11 is controlle-l
by viscous rotor 14 through viscous rotor pinion 13 and idler
gear 12.
!l Since four~h gear 15, with hand 16 thsreon is engaged wi~h
llviscous rotor pinion 13 through fourth idler gear 12, Eourth
Il ,
!l lo
131 1364
gear 15 is rotated at a speed ratio corresponding to tlle nulllber
o ~eeth on the gears. Hairspring gear 9 and hairspring pinion
11 can be independently rotated about winding stem 23 arouncl
the same axis. ~airspring gear 9 is coupled to hairspring pinion
11 through hairspring 10.
When rotor 5 is driven in a stepwise fashion, hairspring
gear 9 is also rotated in a stepwise or discrete fashion.
llowever, hairspring pinion 11 is continuously and smoothly rotated
since its rotation is controlled by the force applied tllrougll
hairspring 10 and the viscous resistance of viscous Eluid 17
surrounding viscous rotor 14. Hairspring 10 permits a diEEerence
or angular deviation between stepwise rotated hairspring gear
9 and continuously rotated hairspring pinion 11. Ilairspring
10, the gear train and the viscous rotor 14 form a vibrating
system in which the viscous resistance is set with substantiall
over-damping so that the system can effectively and reliably¦
¦per~orm even with great variations in external stresses and¦
turbulences.
Viscous rotor 14 converts the rota~y energy stored in
hairspring 10 into a constant rotary speed correspondiny tol
the elastic deformation restoring force of hairspring 10. !
llairspring 10 functions as a storage mechanism for storing the,
intermittently generated rotary energy in rotor S. Since the
torque balance can be set as desired, the size, lay out oE
components and viscosity of the viscous fluid can be easily
selected.
Reference is next made to Fig. 4 wherein the relationsllip
between the wrapping angle of the hairspring ~ and the
restoring force Th of the hairspring is shown. The graph shows
the relationship between the torque Th necessary to restore,
1 31 1 364
the hairspring through angle ~ ~l and the increment ~ T to achieve'
a wrapping angle ~ per stepping motor step. Fig. 4 alsol
shows the effect of an increase of ~ in the wrapping angle¦
on torque when the hairspring is already wrapped at angle ~
¦~5 clearly seen Fig. 4, there is a linear relationship be~ween,
¦the restoring force and wrapping angle.
Reference is next made to Fig. 5 wherein the relationship¦
between the angular velocity Ws f the viscous rotor and the
load torque Th against the rotation of the viscous rotor as
the timepiece hand sweeps, i.e. moves smoothly continuously
at a constant speed. When the reduction ratio of the gear train
between the hairspring and the viscous rotor is b, the angular,
velocity T~S and Ws+ ~W .correspond to load torques of b-(TI~) and
~(Th + ~ T) respectively. Thus, to assure that the hand moves
¦smoothiy, the fraction L~W/Ws should be reduced. That is, ~he~
frac~ion ~T/Th shouid be reduced. When the value o~ b~(Th);
¦is greater than the torque L~ T for a single step, the viscous
¦ rotor will rotate with the angular velocity Ws in a condltion
¦in which the hairspring stores the torque associated with several~
¦steps so that smooth angular rota~ion is achieved. To achieve
this result the spring constant of hairspring 10 may be lowered
;or the viscous load presented by viscous fluid 17 to viscous
rotor 14 may be increased.
In the structure described above, the viscous rotor rota~es
at the constant speed at which the torque of the hairsL~rillc~
is balanced with the load torque. The load torque of the viscous
¦¦rotor is pr.oportional to the angular velocity of the viscous
; ~Irotor, thereby preventing the hairspring pinion from cl~angillcJ
il
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1 131~364
¦speed. As a result, the hand movement is smooth and constant¦
¦and does not move in discrete increments.
l Even if the load torque changes in accordance with thel
¦change of viscosity, continuous and smooth hand movement is¦
¦achieved. Although the wrapping angle of the hairspring is¦
¦increased or decreased, because the hairspring is made o~ al
¦desirably elastic material continuous sweeping movement is still¦
¦present. Even under this situation, the hand keeps movin~ as¦
l long as the stepping motor does not stop.
When timepiece 210 to be set to the correct time, the
operation of the timepiece is controlled by a control lever
20 which interrupts the movement of fourth gear 15 and thereby~
stops the hand movement and the movement of viscous rotor 14.i
~lowever, because hairspring 10 is elastically deformed wheni
the hand movement i8 stopped, continuous sweeping hand movelnellt,
will resume as soon as the control lever 20 i~ released. When
timepiece 210 is violently disturbed, the viscous rotor controls
the extra rotation and elastic deformation of hairspring loi
and the positlon o the hand is correctly displayed in smooth
fashion. Since the hairspring can provide reverse torque ~o
rotor pinion 13, Eurther stability against external turbulance
is provided, allowing the gear train including viscous rotor;
pinion 13, viscous rotor 14, idler gear 20 and fourth year 15
to rotate in both a forward and a reverse direction.
Reference is next made to Fig. 6 wherein an electronic
timepiece 220 constructed in accordance with a second embodiment
l, of the invention is depicted. Like reference numerals refer
I to like elements. Electronic timepiece 220 delivers s~epwise
,1 or incremental rotational energy to hairspring 10 in tlle same
l ~ashion as does timepiece 210 shown in Figs. 2 and 3. The
I
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rotational force from hairspring 10 delivered to hairspring¦
pinion 11 is directly transmitted to meshing ~ourth gear lS.I
Viscous rotor 14 controls the angular velocity of ~ourth gearl
and thereby controls the release of energy from hairspring¦
through rotor pinion 13. In this structure, the size of
the gear train is redùced and the compactness and cost reduction
oE the timepiece construction is improved.
l In addition, since the members of the gear train from the !
¦hairspring 10 to viscous rotor 14 (i.e. hairspring pinion ll,j
¦Eourth gear 15 and viscous rotor pinion 13) also functlon to !
¦transmit the stored energy, any backlash is prevented by thel
Eorce stored in hairspring 10 so that hand 16 correctly operates.3
Reference is next made to Fig. 7 wherein an electronic
timepiece, generally indicated as 230, constructed in accordance
with a third embodiment of the invention i5 depicted. Like
¦ elements are represented by like reference numerals. A fourth
idler gear L2 is provided between fourth gear lS and hairspring
pinion 11 so that a large amount of spacing is provided between
¦the respective axes of fourth gear 15 ~and the display hand
¦16 which is coaxial therewith) and hairspring gear 9 so that
¦additional flexibility of gear placement within timepiec-e 23~)
is available to minimize the thickness of the timepiece.
Reerence is next made to Fig. 8 wherein as electronic
timepiece, generally indicated as 240, constructed in accordance
with a fourth embodiment of the invention is depicted. Like
elements are represented by like reference numerals. Idler
gear 12 is provided between fourth gear lS and viscous rotor
!I pinion 13 so that fourth gear 15 and cavity 19 can be spaced
~lapart within electronic timepiece 240 to provide increased
' ~lexibility of arrangement o~ components which aids in reducing
, . . .
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131 1364
the thickness of the timepiece.
Reference is next made to Fig. 9 wherein an
electronic timepiece, generally indicated as 250,
constructed in accordance with a fifth embodiment of the
invention is depicted. Like elements are represented by
like reference numerals. Fig.9 shows some of the
additional conventional components included in an
electronic timepiece, excluded in Figs. 2-3 and 6-8 to
simplify explanation of the invention. Timepiece 250
includes a battery 36, a quartz vibrator 35, a circuit
substrate 34 and an integrated timekeeping circuit 33.
The driving waveform to drive rotor 5 of the stepping
motor is supplied to coil 1 through circuit substrate 34
by integrated circuit 33 and Quartz vibrator 35. A time
setting gear 24 engages with a clutch gear 37, in response
to the operation of a yoke 30. Yoke 30 is driven by a
time setting lever 31 in response to the operation of a
winding stem 32. This makes it possible to change the
positions of the hands. A third gear 25 steps down the
rotation of fourth gear 15, which engages with the second
hand, to drive the minute hand. A minute gear 23 engages
with setting gear 24.
Hairspring 10 is prevented from moving along its axis
by lips 9a. A groove 9c in hairspring gear 9, to which
the end of hairspring 10 is coupled, allows the torque to
1 3 1 1 364
be transferred from hairspring gear 9 to hairspring 10. A
fourth idler gear 12 is disposed between and engages
hairspring pinion 11 and fourth gear 15. A viscous rotor
idler gear 18 is disposed between fourth gear 15 and
viscous rotor pinion 13. Fourth idler gear 12 and viscous
rotor idler gear 18 allow for greater separation of the
various gear components and cavity 19 so that they may be
spaced apart and thereby reduce the overall thickness of
timepiece 250.
By utilizing the construction shown in Fig. 9, the
viscous rotor 14 and hairspring gear 9 can easily be
arranged without overlap 80 that a particularly thin
timepiece can be easily constructed. The invention is not
limited to the particular physical arrangement of the
various elements shown in the figures and may be adapted
to any appropriate arrangement in accordance with the
specific needs and other timepiece elements present.
Reference is next made to Fig. 10 wherein an
electronic timepiece, generally indicated as 260,
constructed in accordance with a sixth embodiment is
depicted. ~ike elements are represented by like reference
numerals. In timepiece 260, hairspring 10 is utilized as
the storage mechanism for storing the angular energy
produced by the stepping motor and viscous rotor 14, which
is loaded with the viscous load of viscous fluid 17, is
131 1364
utilized as the control mechanism. The timepiece elements
shown, except for hand 16 and the shaft through which it
is attached to fourth gear 15, are all located between a
main plate 21 and a gear train bridge 22. This provides
for a sturdy but thin timepiece. A coil 1 drives rotor 5
through a stator 4 with a magnetic core 2 defining a
magnetic flux field. Hairspring pinion 11 and hairspring
gear 9 are connected to the opposite ends of hairspring
10. Hairspring 10 is wound by the stepwise rotation of
rotor 5 through the gear train including fifth gear 7,
fifth pinion 8 and hairspring gear 9. The rotation of
fourth gear 15 is controlled by viscous rotor 14, which is
~upported between gear train bridge 22 and cavity member
l9a, through viscous rotor pinion 13 and viscous rotor
idler gear 26.
Hairspring gear 9 and hairspring pinion 11 are
allowed to freely rotate on the same axis while fourth
idler 12 and viscous rotor idler gear 26 are rotatably
mounted on idler
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1311364
axis 29, the range of rotation being greater than the range
oE the backlash to engage with fourth gear 15. With this
construction, when rotor 5 is driven in a stepwise or intermittent
fashion, the angular velocity of hairspring pinion 11 is
controlled by viscous rotor 14, which has a load torque which
varies directly with the angular velocity of viscous rotor 14
through fourth idler gear 12, viscous rotor idler 26 and fourth¦
gear 15. As a result, the angular deviation between
intermittently driven hairspring gear 9 and hairspring pinion
11 is absorbed as stored energy by hairspring 10 so that
hairspring pinion 11 can rotate continuously and smoothly at¦
a constant speed corresponding to the elastic deformation !
restoring force of hairspring 10.
Re~erence is next made to Fig. 11 wherein an electronic
timepiece, generally indicated as 270 constructed in accordance
with a seventh embodiment of the invention is depicted. Like
elemen~s are represented by like reference numerals. Electronic
timepiece 270 utilizes a magnetic escape~ent as the control~
mechanism and a first following magnet as the storage mechanism.'
~ driving magnet 51 is coupled to a driving gear 59 for rotation
therewith. Driving gear 59 is driven in a stepwise manner by
rotor gear 6 which is coupled to rotor S. A first following
magnet 52 is spaced a small distance away from driving magnet
51. First following magnet 52 is coupled to a following pinion
57, which in turn is connected to an escapement gear 53.
Following pinion 57 is coupled to fourth gear 15 (and hand 16,
¦jcoupled through a shaf~ 16a), through idler gear 55 and idleL
¦¦pinion 55a.
!1
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!l
. 11
1311364
~ magnetized pendulum 54 is attracted to the teetll o~l
escapement gear 53 by magnetic force resulting from the rotation¦
of escapement gear 54.
The construction of escapement gear 53 and magnetized
pendulum 54 is shown in greater detail in Fig. 13. As escapement
gear 53 rotates due to the driving force applied to first
ollowing magnet 52 by driving magnet 51, pendulum 54 begins
~o vibrate. Pendulum 54 quickly comes to vibrate at a resonant
frequency or other stable fre~uency which then acts as a control
on the rotation of escapement gear 53 and, hand 16 through the
! gear train connecting them.
In this arrangement, the regular application of angular
energy applied to first following magnet 52 at regular intervalsl
in response to the movement of the stepping motor, results in !
a uniform speed and excellent sweep hand movement. Magnet !
pendulum 54 incude~ a mounting member 54a mounting pendulu~
54 on the main plate 21, gear train bridge 22 or other structure!
with mounting member 54b. Magnetic pendulum 54 is vibrated
at its distinctive frequency in the direction of arrows ~ ( Figs.
11, 13). Magnetic pendulum 54 does not physically contact'
escapement gear 53, as seen more clearly in Fig. 13. This'
minimizes the friction in the system and the resulting power'
loss and increases the precision of vibration of pendulum o~
member 54. Accuracy of rotation of escapement gear 53 and hand
16 are thus improved.
Reference is next made to Figs. 12, 14 wherein an electronic
timepiece generally indicated as to 80, constructed in accordance
wi~h an eight~l embodiment of the invention is depicted. Like
Il elements are represented by like reference numerals. Whereas
1, pendulum 54 surrounds escapement gear 53 on bo~h sides in
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131 1364
timepiece 270 sllown in Fig. 11, pendulum 56 in timepiece 280
is surrounded by two part escapement gear 53a, 53b. Pelldulum¦
56 is made of a magnetic material and plate spring 56a is fixed
in place by mounting member 56b. Pendulum 56 is attrac~ed by
the magnetic force when pendulum 56 leaves the magnetic flux
of an attractive magnet 58 provided between escapement gears
53a and 53b. This construction enables a stronger magnetic
~lux to be produced than when a magnetized pendulum as shown
in Figs. 11, 13 is used so that a more accurate, continuous
hand movement is achieved.
With the use of a magnetic escapement as the control
mechanism as shown in Figs. 11-14, the pendulum is only coupled
to the teeth of the escapement gear or gears by a magnetic force.
No direct physical contact between the teeth of the escapement
gear and the pendulum is present. When the pendulum vibrates
i at its peculiar or resonant frequency the escapement gear is,
rotated at a uniform speed responsive to the external driving~
~orce supplied by driving magnet 51. Thus, the intermittent
rotational energy generated by the transducer (step motor
including rotor 5) i8 stored by the first following magnet as
an angular deviation from driving magnet 51 and the stored energy
is released to the escapement gear as a driving force under
the control o~ the pendulum. The escapement gear is thus rotatc<l
at a substantially uniform speed until driving magnet 51 ceases
to provide rotational energy. However, once driving magne~
51 again begins to rotate, sweeping hand movement again con~ences.
At this time, since the frequency may have been altered slightly
by ~he change in load (i.e. the vibrational amplitude), even
llif tlle distinctive frequency is not accurately adjusted, tl-e
!escaPement gear rotates at an angular velocity direc~ly
. 1
!
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.:
,
., :
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~ 1311364
proportional to the load of the attracting magnet and vibrating
period. Even iE the vibrating period of the pendulum changes;
due to external inputs such as a shock, and t.he magnetic
connection is broken, after the stored rotational energy is
released, the hand movement will stop. Thereafter, once ~otor
again begins rotating which causes the rotation oE drivillg
magnet 51, continuous movement of the hand will start again.
Thus, if the driving magnet is driven by a quartz crystal
oscillator or the like, synchronous continuous driving oE hand!
16 will continue for a relatively long time.
Accordingly, in timepieces 270 and 280 shown in Figs. 11-14,
sweeping hand movement at a uniform speed is achieved without
any harmful affects on the driving power or variations due to
temperature or even change in speed due to fluid leakage or
the like. The non-contacting nature of the pendulum and teeth
o~ the escapement gear serves to increase the durability of
the system and reduce the consumption of energy so that batteriesi
or other electric cells can drive the timepiece for extended
periods of time.
Re~erence is next made to Fig. 15 wherein a control mechallism
in accordance with the viscous fluid arrangement i5 depicted.
_ Like elements are represented by like reference numerals.
rim member 13e, a first opening 13f and a second opening 66
are provided in viscous rotor pinion 13 which is intec3rally
formed with a common rotational axis and structure with viscous
rotor 14. A cavity 19 is defined by a cavity member 19a and
encloses viscous rotor 14 and viscous fluid 17. Cavity member
19a has a groove 65 and a sloping portion 67. A cap 60 whicl
¦Ihas mating portion fitting into groove 65 acts to confine viscous
1l fluid 17 to cavity 19. Sloping portion 67 allows the easy pourinc~
1~ .
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131 1364
of viscous fluid 17 into cavity 19 without spilling or
splashing. Gap 60 has a burred portion 60a which curves
upwardly and forms a gap 61 with viscous rotor pinion 13.
Pinion 13d of viscous rotor pinion 13 is rotatably
supported in cavity support portion l9b. Rim member 13e
prevents viscous fluid which leaks out of cavity 19 from
entering teeth 13g, in conjunction with first opening
portion 13f. Second opening portion 66 provides
additional space to deal with any thermal expansion of
viscous fluid 17 due to variations in temperature. Groove
65 effectively joins with cap 60 to prevent leakage of
viscous fluid around the edges of cavity 19. In addition,
a sealing treatment is performed at gap 61 on the opposed
sur~aces of the cap and rotor pinion to prevent any
leakage through gap 61. Burred portion 60a, in addition
to providing a narrow gap 61 also serves to extend the
length of the gap 61 so that leakage of the viscous fluid
through gap 61 is prevented by the resistance to fluid
flow of the long narrow gap.
Reference is next made to Fig. 16 wherein a viscous
rotor and viscous fluid assembly in accordance with
another embodiment of the invention in which a magnetic
fluid is utilized to seal cavity 19 is depicted. Like
elements are represented by like reference numerals.
Rather than having an open gap 61 as in the embodiment of
131 1364
Fig. 15, a magnetic fluid 161 is placed in gap 61 to
prevent the outward flow of viscous fluid 17. A mounting
portion l9c of cavity member l9a supports a yoke 63 which
supports pivot frame 64 and confines magnet 62 with
magnetic cap 60. Magnetic axis 13a is formed of a
magnetic material and serves as a rotating axis on which
viscous pinion 13 is mounted for transmitting the
frictional torqus of viscous rotor
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X
13~1364
l~l and viscous fluid 17 to the remaining portion oE tl~e drive¦
train not shown in Fig. 16. A magnetic field is formed by yoke
63, pivot frame 64, pinion 13, axis 13a, cap 60 and burringl
portion 60a to trap magnetic fluid 161 in gap 61 between rotor¦
yoke 13b and burring portion 60a of cap 60. In a construction¦
such as shown in Fig. 16, the viscous fluid can be formed in¦
a preferred embodiment oEsilicone oil with the magnetic Eluicl¦
desirably formed oE a fluorine solvent, thereby preventin~ the¦
viscous fluid from leaking out oE cavity 19. I
Reference is next made to Fig. 17 wherein an electronic¦
timepiece generally indicated as 290 constructed in accordance¦
with a ninth embodiment of the invention is depicted. Lik~
elements are represented by like reference numerals. Timepiece
290 utilizes a pair of magnets, i.e. a driving magnet anct a
following magnet as the storage mechanism and a viscous ~luid
assembly as the control mechanism.
Rotor 5 of the stepping motor is rotated in response to
the current supplied to coil 1, which is wound around magnetic
core 2, through stator 4. Driving magnet 51, which is driven
through the gear train including fifth gear 7, Eiftll piniorl
8 and driving gear 59, stores the rotational energy of rotor
5 as the angular difference between driving magnet 51 and
followi~g magnet 52. The magnet attractive force increases
as the angle between driving magnet 51 and Eollowing magne~
52 increases from 0 to 90. Fourth idler gear 12 engages wi~h
ourth gear 15 which engages with hand 16, viscous rotor pinion
13 and following gear 57. Viscous rotor pinion 13 is conllcc~ct
to viscous rotor 14 wllicll, as described above, is sublnerscd
llin viscous fluid 17 within cavity 19. The angular deviation
ll~etween driving magnet 51 and following magnet 52 is graduaJly
,1 ,
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,,
1 31 1 364
restored and energy gradually released as the rotational
speed of fourth idler gear 12 which is controlled by the
viscous friction. As a result, indicating hand 16
smoothly rotates.
In the construction of timepiece 290, following
magnet 52 is supported between gear train bridge 22 and
main plate 21 so that a sufficient span and stability is
achieved. In addition, because viscous rotor idler gear
26 is separated from fourth gear 15, a thin timepiece is
easily constructed without producing a tilted sweep second
hand suffered by the prior art timepiece. An additional
benefit of the separation of the storage mechanism formed
of the magnets and the control mechanism including the
viscous fluid assembly is the absence of interaction which
ensures reliable continuous sweeping hand movement.
Referencs is next made to Fig. 18 wherein an enlarged
view of the hairspring gear 9, hairspring 10 and
hairspring pinion 11 embodying the invention is depicted.
Like elements are represented by like reference numerals.
Hairspring pinion 11 has a hairspring connector 70 within
hairspring gear 9. Hairspring 10 is constructed so as to
be enlarged upon application of a load and it is caulked
to connector 70 at a caulking portion 70a. The inside end
of coil hairspring 10 is connected to caulking portion
70a. The outside end of hairspring 10 is connected to
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1 3 1 1 364
hairspring gear 9 at groove portion 9c. In this way,
hairspring 10 is coupled between hairspring gear 9 and
hairspring pinion 11 so that rotational energy is stored
as an elastic deformation of hairspring 10 dependent upon
the angular deviation between hairspring gear 9 and
hairspring pinion 11. Movement of hairspring 10 along the
axis of hairspring gear 9 and hairspring pinion 11 is
restricted by lip portions 9a shown also in Fig. 9 and
sloping portion
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~ 1311364
9b. ~tl escapement portion lla is formed so as to prevellt¦
hairspring gea- 9 and hairspring pinion 11 from contactin~ each
o~l~er under various situations, such as wllen hairspring pinio
rocks from side to side.
l TJlis construction allows hairspring 10 to be easily assembled
¦and, because the frictional load between hairspring pinion 11
and hairsping gear 9 is small, this construction provides
excellent efficient sweeping hand movement.
Reference is next made to Fig. 19 wherein a portion of
a semiconductor device 300 constructed in accordance with a
_ te~ltl~ embodiment of the invention is depicted. Li~e elements
are represented by like reference numerals. Electronic timepiece
300 is characterized by a removable control mechanism so that~
upon removable oE the control mechanism intermittent hand movement
is achieved.
The detachable control mechanism includes Cavity
19 with cap 60, and viscous
rotor pinion 13 assembly. The assembl~ I
is inserted through opening 81 in main plate 21 until viscous !
rotor pinion 13 etlgages with idler géar 12 so that the rotation
of hairspring pinion 11 is controlled by the viscous resistance.
¦Cavity 19 is prevented from itself rotating by the locking~
interaction of notched portion 87 and engagement member 80 ofi
idler gear 12 on main plate 21.
In this way, the control mechanism can be optimally Eormed~
and flexibly assembled and tested apart from the timepiece.
- ¦I'L`he removable nature of the entire control mechanism also allows
¦Ifor easier repair of the timepiece. Finally; the timepiece can
llbe nlalluFactured in the same fashion whether a timepiece witl
30 '! a stepping hand movement or a continuous sweeping lland movemetlt
11
" - 24 -
is desired. In the event that a sweeping hand movement lS desired
the control mechanism can be inserted. Otherwise, the timepiece
will function with a stepping hand movement in the absence of
the control mechanism. The control mechanism is shown mounted
on the main plate side of timepiece 300 but may be mounted on
the gear train bridge side and can be formed in a variety of
shapes and sizes.
~ccordingly, an electronic timepiece which stores discrete
rotational energy as either the elastic deformation force oE
a hairspring or other elastic member or the magnetic attraction
force between magnetic materials and which then discharges the
stored rotational energy gradually through a control means,
either with a viscous rotor and viscous resistance or a magnetic;
escape~nent is provided. In each case the storage mechanismj
and control mechanism are separately formed. This enables smooth,l
sweeping hand movement. The constructions de8cribed above are¦
not limited t~ the specific embodiments shown and described.l
In addition, Applicant's invention may be applied to the !
conversion of discrete rotational energy to continuous sweeping
motion in applications beyond timepieces.
In the timepiece embodiments, a sweeping hand movement
which incorporates the extremely accurate timekeeping qualities~
of the quartz system as well as the ability to prevent increases
in thickness of the timepiece or shortening of the life expectancy
of the battery cell used to operate the timepiece is achieved.
Accordingly, an analog timepiece which converts intermittent
stepping motion of the timekeeping circuitry to a continuous
¦¦sweeping hand display by separating the mechanism for storing
¦¦the rotational energy and the control mechanism for smootllly
1l releasing the stored energy is provided.
I!
, - 25 -
1 1311364 I
It will thus be seen that the objects set Eorth above,l
among those made apparent from the preceding description, are¦
efL` ciently attained and, since certain changes may be made¦
in the above constructions without departing from the spirit
~nd scope oE the invention, it is intended that all matter¦
contained in the above description or shown in the accompanyingl
clrawings shall be interpreted as illustrative and not in ai
limiting sense.
It is also to be understood tht the following claims are
intended to cover all of the generic and specifi~c features oE'
the invention herein described and all statements of the scope
oE the invention which, as a matter of language, might be said
to fall therebetween.
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