U.S. patent number 3,906,713 [Application Number 05/500,891] was granted by the patent office on 1975-09-23 for electronic alarm wristwatch.
This patent grant is currently assigned to Citizen Watch Co., Ltd.. Invention is credited to Fujio Ishida, Haruo Suda.
United States Patent |
3,906,713 |
Suda , et al. |
September 23, 1975 |
Electronic alarm wristwatch
Abstract
This invention relates to an electronic alarm wristwatch wherein
apertures are provided on the back cover to release alarm sound
generating upon the coincidence of the time preset by an
alarm-presetting device and that designated by a time display or
time keeping means. A sound-emitting piezo-electric or
electro-strictive element is fixed to the membrane which is
dish-shaped and has a plurality of concentric wrinkles, said
membrane is so placed in the watch case as not to waste any space
and insures water- and dust-proofing. A distribution board is fixed
to the wrinkled portion of said membrane to provide the required
electric current, thereby providing an electric alarm watch which
sounds freely and is not disturbed by oscillation of the wrist.
Inventors: |
Suda; Haruo (Tokorozawa,
JA), Ishida; Fujio (Kokubunji, JA) |
Assignee: |
Citizen Watch Co., Ltd. (Tokyo,
JA)
|
Family
ID: |
26438042 |
Appl.
No.: |
05/500,891 |
Filed: |
August 27, 1974 |
Foreign Application Priority Data
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|
|
|
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Aug 29, 1973 [JA] |
|
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48-96881 |
Sep 10, 1973 [JA] |
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48-101860 |
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Current U.S.
Class: |
368/255; 968/970;
968/591 |
Current CPC
Class: |
G04G
13/021 (20130101); G04C 21/20 (20130101) |
Current International
Class: |
G04C
21/00 (20060101); G04C 21/20 (20060101); G04G
13/00 (20060101); G04G 13/02 (20060101); G04C
021/00 (); G04B 023/12 () |
Field of
Search: |
;58/38,57.5,152R |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Jackmon; Edith Simmons
Attorney, Agent or Firm: Spensley, Horn & Lubitz
Claims
We claim:
1. An electronic alarm wristwatch comprising a time display means,
an alarm presetting device, an alarm circuit means for operating
upon the coincidence of the time preset by said alarm presetting
device and that designated by said time display means and for
providing an electrically varying signal upon said coincidence, an
electro-means for vibrating when energized by said alarm circuit
with said varying signal, a membrane on which said electro-means is
fixed to be thereby vibrated, a back cover having apertures to
release sound waves emanating from the membrane out of the watch
case, and a case band holding said back cover, wherein said
membrane is dish shaped with a plurality of concentric wrinkles,
the central portion and rim thereof are flat, said electro-means is
fixed on said central portion, and said rim is placed between said
back cover and case band.
2. An electronic wristwatch according to claim 1, wherein said
electro means is selected from the group consisting of a
piezo-electric element and an electro-strictive element.
3. An electronic alarm wristwatch according to claim 1, wherein
said back cover can be separated from said membrane.
4. An electronic alarm wristwatch according to claim 2, wherein a
distribution plate is provided for connecting electric current
necessary to drive said electro means, said distribution plate
being fixed onto a wrinkle of said membrane.
5. An electronic alarm wristwatch according to claim 4, wherein a
watch movement is encased within the watch case, said watch
movement having a terminal spring therein, and at least one
ring-shaped electric conductor arranged on the distribution plate
to provide electrical connection to said terminal spring.
6. An electronic alarm wristwatch according to claim 4, wherein an
opening is provided in the central portion of the distribution
plate for access thereto.
7. An electronic alarm wristwatch according to claim 6, wherein
said opening is closed with a soft material.
8. An electronic alarm wristwatch according to claim 5, wherein a
perforation is arranged in the conductive portion of the
distribution plate through which electric connection is effected
between the electro-means and the conductor.
9. An electronic alarm wristwatch according to claim 4, wherein an
alarm circuit is fixed onto the distribution plate.
10. An electronic alarm wristwatch according to claim 4, wherein
said alarm circuit is placed between the distribution plate and the
membrane.
11. An electronic alarm wristwatch according to claim 1, wherein a
rubber packing is placed between the case band and the membrane.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an electronic alarm wristwatch.
2. Prior Art
Prior art devices disclose an electronic alarm wristwatch in which
a form of electro-magnetic buzzer is employed to beat the glass or
metal back cover by means of an electro-magnetically driven hammer
or other oscillating means. However, this type of alarm device
requires considerable space to allow the oscillating means to work
and additional space to house electro-magnets, making it necessary
to enlarge the size of the watch.
In an attempt to overcome these drawbacks, an electronic buzzer in
which a piezo-electric or electro-strictive element has been fixed
to the membrane has been used instead of the aforementioned
electro-magnetic buzzer. The alarm wristwatch of the electronic
buzzer type has on its back cover an aperture to release the sound
emanating from the membrane out of the watch case; therefore, the
watch is neither waterproof nor dustproof. In order to improve this
shortcoming, the case band has been compressed with a composite
back cover comprising a flat membrane and the back cover fastened
together as a single entity. However, the composite back cover also
has a drawback in that there exists a large and unnecessary space
surrounded by the membrane and the inside wall of the back cover.
By compressing the case band and the composite back cover together
the size of the watch must necessarily be large. In addition, the
watch of this type employs a driving means utilizing a
piezo-electric or electro-strictive element, whereby electric
connection between alarm circuit provided on the watch movement and
the piezo-electric or electro-strictive element fixed to the
membrane is accomplished by a terminal pin provided on the membrane
and a terminal spring provided on the movement which resiliently
contacts said terminal pin. This necessitates the device have an
area in which the terminal pin and terminal spring are arranged
between the movement and the membrane. Therefore, in conventional
devices using a flat membrane, the size of the watch must be large
enough to provide said space.
A further drawback in above arrangement exists in that the membrane
does not oscillate properly since the terminal pin provided on said
membrane is elastically attached to the terminal spring in the
watch movement. It is also difficult and impractical, for example,
to arrange and place parts such as an alarm circuit, in addition to
the piezo-electric or electro-strictive element, on the membrane
for the following reasons: (1) such elements tend to interfer with
the oscillation of the membrane, (2) such elements require area
which is limited, and (3) there is a possibility of electrical
disconnection.
Resilient contact between the terminal pin and terminal spring also
presents a problem in that electric connection may not always be
effected due to the nature of the placement of the membrane and the
watch movement upon which the terminal pin and terminal spring are
respectively fixed.
BRIEF SUMMARY OF THE INVENTION
The primary object of this invention is to provide an electronic
alarm wristwatch comprising a time display means, an alarm
presetting device, an alarm presetting circuit operating upon the
coincidence of the time preset by the alarm presetting device and
that designated by the time display means, a piezo-electric or
electro-strictive element driven by said circuit, a membrane on
which said element is fixed, a back cover having apertures to
release sound emanating from said membrane out of the watch case,
and a case band supporting said back cover, wherein said membrane
is dish-shaped with a plurality of wrinkles formed by a metal
forming process, and having a central portion and brim thereon that
are flat. The piezo-electric or electro-strictive element is fixed
on said central portion, and said brim is held between said back
cover and said case band.
Another object of this invention is to provide an electronic alarm
wristwatch having a dish-shaped membrane with a wrinkled portion.
On the wrinkled portion is installed a distribution plate, said
plate having a ring-like conductive portion thereon which connects
to a touch spring thereby providing electric connection.
Still another object of this invention is to provide an electronic
alarm wristwatch having an alarm circuit fixed on the distribution
plate.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a plan view of the back cover of a known alarm
wristwatch.
FIG. 2 is a sectional view along Line II--II' of FIG. 1.
FIG. 3 is a plan view of the buzzer unit of an embodiment of this
invention.
FIG. 4 is a sectional view along Line IV--IV' of FIG. 3.
FIG. 5 is a sectional view of the overall structure of the watch
described in the same embodiment, with a schematic electric circuit
coupled to the watch.
FIG. 6 is a sectional view of a variation of the embodiment shown
in FIG. 5 .
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIG. 1 in which a plan view of the back cover of a
known electric alarm wristwatch is shown for comparison, back cover
10 has plural apertures 20, 22, 24, 26, 28, 30, 32 and 34 provided
in slope 12 of said back cover 10 so that the sound being generated
within the case can efficiently be heard through the apertures
without being blocked by the wrist. Referring to FIG. 2 which shows
a sectional view along Line II-II' of FIG. 1, back cover 10 is dish
shaped having a slope 12, brim 14, and recessed room 18 surrounded
by the inner wall of back cover 10. A plan view of the buzzer unit
of an embodiment of this invention is shown in FIG. 3 where buzzer
unit 36 has a covering case consisting of membrane 38 made of
titanium material which has little material loss of oscillations
and prevents erosion from sea water.
The construction of buzzer unit 36 is better shown in FIG. 4, where
membrane 38 has a dish shape provided with plural concentric
wrinkles 40, 42, 44 and 46 including brim 40 and central flat
portion 46. The term "wrinkles" as employed herein may include the
bent portion and a flat portion or only a bent portion or only a
flat portion. The membrane 38 can be easily processed in any manner
suited for mass production, such as by a metal forming process, to
form wrinkles. Membrane 38 has a recessed space 50 surrounded by
flat brim 40 and inside wall 48. Piezo-electric or
electro-strictive element 54, made of BaTiO.sub.3 or
Pb(TiZr)O.sub.3, and distribution plate 62 are arranged in recessed
space 50 with piezo-electric or electro-strictive element 54
adhered to central flat portion or wrinkle 46 of inside wall 48
with a conductive adhesive agent of epoxy resin. Preformed on each
side of element 54 is a silver electrode and after being fixed to
membrane 38 it is treated for polarization with a DC electric field
from the outside. Distribution plate 62 is fixed concentrically
along wrinkle 44 of membrane 38 with an insulative adhesive agent
of epoxy resin. This plate 62 includes conductive portions 66
thereupon. In this embodiment, distribution plate 62 is made of a
glass-containing epoxy plate, and gold-plated, ring-shaped
conductive portion 66 is provided thereupon. Said plate 62 has a
hole 68 at the center for soldering operation, through which
soldering of lead line 70 to the electrode of piezo-electric or
electro-strictive element at soldering portion 56 is possible even
after distribution plate 62 has been fixed onto membrane 38. In
addition, conductive portion 66 has a perforation 58 through which
lead line 70 is passed, one end thereof reaching soldering portion
56 to be soldered and the other end reaching soldering portion 60
of conductive portion 66 to be soldered, thus enabling electrical
connection to the system. Upon completion of the soldering
operation, sheet 72 made of any soft material is coated or secured
over hole 68, the purpose of which is to prevent extraneous
substances from falling onto membrane 38 which would impede proper
oscillation of said membrane 38. The soft material used for sheet
72 is preferably made of air circulating fiber so as to lessen the
possibility of impedance caused by sound pressure accompanying
oscillation of said membrane. Since the sound originates at the
central portion 46, rim 40 and wrinkles 42 and 44 of membrane 38
have little or no effects upon the sound.
Buzzer unit 36 thus constructed has less chance of damage with
respect to the piezo-electric or electro-strictive element 54 and
of disconnection of lead line 70, since lead line 70 is distributed
within space 52 surrounded by distribution plate 62 and central
portion 46 of membrane 38 and since the distribution plate 62 act
as a mechanical shield for piezo-electric or electro-strictive
element 54 and lead line 70.
The overall structure of the watch of this invention is shown in
FIG. 5. Watch 74 of this embodiment comprises the buzzer unit 36
which is installed in recessed space 18 formed by back cover 10.
The circular rim of the buzzer unit is removably fixed to the room
between flat rim 40 of membrane 38 and rim 14 of back cover 10 and
the inner bottom surface of band 78 having rubber packing 79
positioned adjacent thereto. This arrangement makes it possible
that when any extraneous substances enter between the outside wall
of membrane 38 and inside wall 16 of back cover 10 through
apertures 20, 22, 24, 26, 28, 30, 32 and 34 and impede oscillation
of the membrane 38, the removability of back cover 10 and membrane
38 makes it easy to eliminate such substances. The central portion
or wrinkle 46 of membrane 38, is spaced an appropriate distance
from inside wall 16 of back cover 10, so that it is free to move.
Further, an intermediate rubber packing 79 is arranged between case
band 76 and rim (or wrinkle) 40 of membrane 38, all of which are
firmly fixed to back cover 10 by ring screw 80 which treadingly
engages case band 76. Instead of using ring screw 80 as in the
present embodiment, back cover 10 may be directly fixed to case
band 76. The use of the rubber packing between case band 76 and rim
(or wrinkle) 40, either with or without screws, results in
waterproofing and dustproofing the watch.
The embodiment as shown in FIG. 5 has watch movement 82 provided
with alarm circuit 84, both of which are completely sealed within
the space formed by membrane 38, case band 76 and glass 86. A
portion of watch movement 82 which is situated below the level of
rim 40 of membrane 38, is placed in recessed space 50 enclosed by
membrane 38. This is because of the dish shape of the membrane
which enables said membrane to be placed along the inside wall 16
of back cover 10 within recessed space 18 of back cover 10 so as to
eliminate wasteful space. Accordingly, the thickness and size of
the watch is reduced by that much of the portion of movement 82
which is contained in recessed space 50. In this embodiment, the
measurements of respective parts are as follows: from the base of
inside wall 16 of back cover 10 to rim 14: 2.9 mm; from rim 40 of
membrane 38 to the base of the outside wall of central portion 46:
2.8 mm; from wrinkle 44 of membrane 38 to base of the inside wall
of central portion 46: 0.5 mm; the thickness of the membrane: 0.1
mm; and the thickness of distribution plate: 0.2 mm. In this
connection a maximum 2.1 mm of watch movement 82 can be contained
within recessed space 50 of said membrane 38.
Thin insulating board 98 and metallic terminal spring 102 are fixed
together by plastic pins 90 and 94 provided on movement 82 by means
of heat press at the tips of pins 90 and 94. Electrical connection
is effected by means of terminal spring 102 resiliently contacting
conductive portion 66 on distribution plate 62 when back cover 10
and buzzer unit 36 are clamped by case band 76. Separation of watch
movement 82 from buzzer unit 36 is facilitated since no lead line
is used for electrical connection between conductive portion 66 and
terminal spring 102. To cope with the possible shifting of the
point of contact on conductive portion 66 by terminal spring 102
resulting from clamping of back cover 10 and buzzer unit 36 to case
band 76, a ring-like conductive portion 66 surrounds circular track
64 (shown by broken line in FIG. 3) with which electrical
connection is effected at any random point as buzzer unit 36
rotates at the time of clamping. Thus it is not necessary to
establish a specific point of contact.
The electrode of piezo-electric or electro-strictive element 54,
which is fixed to membrane 38 with a conductive adhesive agent, is
grounded to a plate on watch movement 82 via membrane 38, back
cover 10, ring screw 80 and case band 76. Terminal spring 102 is
electrically connected by lead line 106 from soldering portion 104
to output terminal 108 of alarm circuit 84. Battery 110 is
electrically connected on the positive side to the plate (not
shown) on watch movement 82 via lead line 112.
A conventional time display means is provided in watch movement 82,
said time indicator comprising any of the following: (1) a device
using a vibrator such as a balance wheel or a tuning fork as a time
standard, a series of reduction wheels, time indicating hands
axially supported by said wheels, and a dial; (2) a device
comprising an oscillator with crystal vibrator serving as a time
standard, a series of frequency dividers, stepping motor driven by
an output from said frequency dividers to move time indicating
hands and a dial, or (3) an electro-optic display such as a liquid
crystal display device, or a light emitting diode device in which
the output from the frequency divider is counted by a calculator or
counters and converted by a decoder.
Also installed in this electronic alarm wristwatch are a
conventional alarm presetting device which is externally operative,
and a conventional alarm circuit which is controlled by the
coincidence of the time preset by said alarm presetting device and
the arrival of said time indicated by the time display means. Said
alarm circuit may be so constructed that piezo-electric or
electro-strictive element is driven by frequency signals from a
crystal oscillator, or it may be constructed according to the
embodiment as described below.
A conventional unlocking switch 114, controlled by the
aforementioned coincidence of time, is directly connected to
battery 110 so as to open or shut off the current route from
battery 110 which connects to alarm circuit 84. Alarm circuit 84
comprises alarm oscillator circuit 116 and alarm presetting circuit
118. Said alarm oscillator circuit 116 basically employs known
unstable or free-running multivibrator; in the present embodiment
said circuit 116 comprises NPN-type transistors 120 and 122,
resistors 124, 126 and 128, booster coil 130 which is connected in
parallel with piezo-electric element 54, and condensers 132 and
134.
Employing a known CR-type timer circuit as a basis, alarm
presetting circuit 118 comprises resistors 136, 138 and 140,
condenser 142 and NPN-type transistors 144 and 146, and operates
upon the constant time designated by resistor 136 and condenser
142. Output port 148 for transistor 144 is connected to the base of
transistor 146. Further, the collector of transistor 146 is
connected to the base of transistor 122 in alarm oscillator circuit
116 thereby controlling alarm sounding time.
In this embodiment the capacity of each part may be specified as
follows: battery: a mercury type 1.3v; resistor 136: 1M.OMEGA.;
condenser 142: 1.mu.F; alarm sounding time within alarm presetting
circuit: about 1-2 seconds; in alarm oscillator circuit 116:
condenser 132: 3300 pF; condenser 134: 330 pF; resistor 126: 33
K.OMEGA.; resistor 128: 33 K.OMEGA.; and oscillating frequency:
about 4K Hz. A maximum sound effect is obtained when the resonance
frequency of wrinkle 46 on membrane 38 of buzzer unit 36 is about
equivalent to the oscillating frequency. The titanium membrane 38
shaped and supported as indicated is particularly compatible with
said oscillating circuit.
The operation of alarm circuit 84 is as follows: U on the arrival
of a preset time, unlocking switch 114 closes, charging the
positive booster coil 130 side of condenser 134, and, since
resistor 126 has a lower resistance than resistor 128, transistor
122 is activated (ON). Thus electrical current flows in booster
coil 130, accummulating magnetic energy therein. Voltage between
base emitters in transistor 120 increases according to the constant
time determined by resistor 128 and condenser 134, and at the same
time condenser 132 is charged on the positive resistor 124 side.
Having thus activated (ON) transistor 120, the voltage between
transistor 122 base emitters decreases rapidly, deactivating (OFF)
transistor 122. Thereupon the aforementioned magnetic energy stored
in booster coil 130 is discharged at once, generating high voltage
in each end of booster coil 130, and drives piezo-electric element
54 which is connected parallel to booster coil 130. When transistor
120 is deactivated (OFF), the voltage between transistor 122 base
emitters begins to increase according to the time constant
determined by resistor 126 and condenser 132. Thereupon condenser
134 is again charged on the positive booster coil 130 side. When
transistor 122 is activated (ON), the voltage in the base emitters
of transistor 120 decreases rapidly, deactivating (OFF) transistor
120. Repeating the above operation, each time transistor 122 is
activated (ON), the electricity flows to booster coil 130.
Oscillation at the rate of approximately 4K Hz causes
piezo-electric element 54 to keep sounding.
Meanwhile, in alarm presetting circuit 118, transistors 144 and 146
are initially deactivated (OFF) when unlocking switch 114 is shut,
but as condenser 142 is gradually charged via resistor 136, the
base voltage in transistor 144 increases accordingly and activates
(ON) said transistor 144. The time required for unlocking switch
114 to close and transistor 144 to activate is 1-2 seconds as
mentioned previously. Transistor 146 is activated (ON) as the
voltage across resistor 140 connecting to transistor 144 emitter
increases. Thereupon the voltage in transistor 122 base emitters is
forcibly decreased, deactivating transistor 122 and thereby
stopping the drive of piezo-electric element 54. This condition
remains until unlocking switch 114 opens once again.
Now referring to FIG. 6 showing a sectional view of a variation of
the embodiment shown in FIG. 5, the membrane 150 is dish-shaped
having a plurality of wrinkles 152, 154, 156 and 158 formed by a
stamping, or progressive drawing process. Membrane 150 is arranged
along inside wall 16 of back cover 10 so that appropriate space is
maintained for wrinkle 158 to oscillate properly. Piezo-electric
element 54 is fixed to wrinkle 158 on membrane 150 by a conductive
adhesive agent. The soldering portion 56 at one end of said element
54 is soldered to lead line 118 which connects to output port 108
of alarm circuit 84. Alarm circuit 84 is installed on the underside
of distribution plate 160 which is fixed to wrinkle 154 of membrane
150.
Terminal 164 in alarm circuit 84 is soldered via lead line 166 to
ring-shaped conductive portion 170 which is inside of concentric
conductive portion 66 on the upper side of distribution plate 160
through hole 172 provided in said distribution plate 160. The other
terminal 162 in alarm circuit 84 is electrically connected to
conductive portion 66 on the upper surface of distribution plate
160.
Buzzer unit 174 comprises membrane 150, piezo-electric or
electro-strictive element 54, distribution plate 160, and alarm
circuit 84. The watch movement comprises a time display means, an
alarm presetting device, unlocking switch 114 linked to said alarm
presetting device, and battery 110. In addition, terminal springs
102 and 178 are insulated from each other so that each
independently and resiliently contact respective conductive
portions 170 and 66 of buzzer unit 174. Terminal spring 178 is
fixed onto thin insulating board 100, both of which are in turn
firmly held by means of heat press to the tips of plastic pins 92
and 96 fixed to watch movement 176. Terminal spring 102 is
connected to the negative side of battery 110, terminal spring 178
connects to the positive side via unlocking switch 114. The
positive side of battery 110 is grounded to the base plate (not
specifically shown) of watch movement 176, and membrane 150, having
piezo-electric or electro-strictive element 54 thereon, is likewise
electrically connected to the base plate of watch movement 176 via
back cover 10, ring screw 80 and case band 76. Accordingly, upon
the arrival of a preset time unlocking switch 114 closes and
activates alarm circuit 84 in buzzer unit 174. Thereupon sound
waves emanate from central portion 158 of membrane 150 on which
piezo-electric or electro-strictive element 54 is fixed.
According to the embodiments described above, the use of the
dish-shaped membrane with its plural wrinkles enables simple
installation of the piezo-electric element, distribution plate,
alarm circuit, etc. on the appropriate wrinkles without hindrance
to the waterproofing and dustproofing functions. Additionally, the
limited space within the watch case is most effectively utilized by
the containment of a portion of the watch movement within the
recessed space on the membrane, thus realizing the manufacture of a
thinner, smaller electric alarm wristwatch.
Further, the buzzer unit assembly is simplified by the fact that
electrical connection can be effected at random since it is not
necessary to choose a specific point of contact with regard to the
rotation of the buzzer unit. In the event of a failure, or of an
inspection of the buzzer unit, repair or inspection is facilitated
since, as an independent entity, the unit can be easily removed
from the watch case and reinstalled equally easily.
As seen above, the electronic alarm wristwatch of this invention
excels in serviceability which adds to its commercial value.
* * * * *