Alarm apparatus

Abstract: An alarm apparatus comprising a rotatably mounted eccentric weight (5); a motor (1,2) for effecting rotation of the eccentric weight (5) at an alarm time so as to cause vibration of the eccentric weight (5) and thereby provide an alarm, and control means for operating the motor (1,2) at the alarm time characterised in that the eccentric weight (5), the motor (1,2) and the control means are all mounted in a common case (10,17).

Description: This invention relates to an alarm apparatus and, although the invention is not so restricted it relates more particularly to an electronic wrist watch having a silent alarm which generates vibration at an alarm time. A silent alarm is sometimes employed in a timepiece or pager. A known clock with a silent alarm is shown in US-A-4,028,882 and in Figure 14. As shown in Figure 14, vibration alarm 27, which may be placed under a pillow, has a case within which there is a vibration alarm motor 28. The motor 28 has an eccentric weight 29 on a rotary shaft of the motor. The vibration alarm 27 is separate from a clock 25 but is electrically connected to the clock 25 through a connection cord 26. The vibration alarm motor 28 is caused to rotate at an alarm set point time, and the vibration alarm 27 is vibrated by the centrifugal force of the eccentric weight 29 generated by the rotation thereof to let a person know the alarm time. On the other hand, a variety of wrist watches with a silent alarm have heretofore been proposed in which a bar, a hammering member or a lever produces vibrations which are imparted to the skin of a user to make the latter aware of the alarm time. For example, Japanese Utility Model Laid-Open Specification No. 188185/1982 discloses, as shown in Figure 15, a wrist watch of the vibration type in which a hammering bar 30 is actuated by a gear 33 or the like and an impact receiving piece 32 is directly coupled to a vibration plate 31 which is struck repetitively to generate vibration which is imparted to the skin of the user at the alarm time. The generation of vibration by rotating an eccentric weight has been employed in the case of clocks and pocket bells that have relatively large sizes as described above. However, such a system has not been previously used in wrist watches, and a practical construction therefor has also not been proposed since an alarm motor for generating vibration is bulky and extra space is required for the eccentric weight. The known wrist watches with a silent alarm which vibrate the skin of the user by means of a bar, a hammering member or a lever are restricted in external appearance, lack general applicability, and are liable to have a poor water-proof function. Furthermore, such wrist watches can produce an uncomfortable feeling in the person who wears them. Moreover, a device of the kind shown in Figure 15 is fundamentally of the same kind as one that produces vibrations by means of a bar or the like; i.e. vibration is effected repetitively and very frequently at short intervals, so that problems the same as those mentioned above are involved. In this case, furthermore, the hammering bar continuously strikes an impact receiving piece, whereby a knocking noise is generated which is not a silent alarm, and its durability is impaired. Such a watch, moreover, has a large number of parts so that it is difficult to make it in a small size and in a reduced thickness. In US-A-4,028,882 there is disclosed an electronic apparatus having a case within which there are rotatably mounted an eccentric weight, a motor for effecting rotation of the eccentric weight at an alarm information so as to cause vibration of the eccentric weight and thereby provide an alarm, and control means for operating the motor at the alarm information. In Patent Abstracts of Japan, vol. 9, No. 262 (P-398) [1985] 19th October 1985 and JP-A-60-111,178 (Suwa Seikosha K.K) 17-06-1985, an electronic timepiece is disclosed having a seconds hand which is driven by a motor comprising a metallic stator provided on one side with photoelectric elements to which a sine wave is applied, and a rotor in contact with the opposite side of the stator. The object of the invention is therefore to avoid the aforementioned disadvantages. According to the present invention, there is therefore provided an electronic apparatus having a case within which there are rotatably mounted an eccentric weight, a motor for effecting rotation of the eccentric weight at an alarm information so as to cause vibration of the eccentric weight and thereby provide an alarm, and control means for operating the motor at the alarm information characterized in that the motor is an ultrasonic wave motor which comprises a vibrator having a piezo-electric element fixed to one side thereof for generating a surface wave thereon, a rotor in contact with the opposite side of the vibrator, a pressure-regulator for generating suitable contact pressure between the vibrator and the rotor, and a support shaft extending substantially perpendicular to a back cover of the case, the support shaft supporting the vibrator, and the rotor being rotatably mounted on the support shaft. The vibrator may drive a rotor, the rotor driving the eccentric weight by way of gearing. The eccentric weight may be mounted for rotation about an axis which is radially spaced from that of the rotor. The apparatus may have time indicating hands which are concentric with the axis of the eccentric weight. In one embodiment, the eccentric weight constitutes or forms part of a time indicating hand of the apparatus. Means may be provided to allow the eccentric weight to be seen from the exterior of the case. In its preferred form, the apparatus is a wrist watch. An alarm apparatus according to the present invention may thus be provided in a small size and in a reduced thickness. It may also have a highly efficient vibration which is generated with a small amount of drive energy. The alarm provided by the apparatus may also be a visual one. The case of the apparatus is preferably such that it can be held in the palm of a hand. The case may have a pin therein and the motor may include a vibrator supported by the pin and having a piezo-electric element bonded thereon for generating a surface wave thereon, there being an eccentric weight wheel having its centre of gravity spaced from its rotational axis and driven by the surface wave. The case may have a main plate therein, the pin being fixed in the main plate. The eccentric weight wheel may, if desired, be supported by the pin. The apparatus may comprise a rotor which is in contact with the vibrator and is rotated by the surface wave. The eccentric weight wheel may be disposed adjacent a glass and the vibrator of the ultrasonic motor may be disposed adjacent a back cover. A portion of the eccentric weight may be viewable through a display portion. The invention is illustrated, merely by way of example, in the accompanying drawings, in which:- Figure 1 is a sectional view of a first embodiment of an alarm apparatus according to the present invention, constituted by a wrist watch having a silent alarm; Figure 2 is a plan view of an eccentric weight wheel forming part of the structure shown in Figure 1; Figure 3 is a plan view of another embodiment of the said eccentric weight wheel of Figure 1; Figure 4 is an external plan view of the wrist watch of Figure 1; Figure 5 is a sectional view of a wrist watch with a silent alarm which constitutes a second embodiment of the present invention; Figure 6 is a plan view of an eccentric weight wheel forming part of the structure shown in Figure 5; Figure 7 is a sectional view of a wrist watch with a silent alarm which constitutes a third embodiment of the present invention; Figure 8 is an external plan view of the wrist watch of Figure 7; Figure 9 is a sectional view of a wrist watch with a silent alarm which constitutes a fourth embodiment of the present invention, Figure 10 is an external plan view of the wrist watch of Figure 9, Figure 11 is a sectional view of a wrist watch with a silent alarm which constitutes a fifth embodiment of the present invention; Figure 12 is a sectional view of a wrist watch with a silent alarm which constitutes a sixth embodiment of the present invention, Figure 13 is an external plan view of the wrist watch of Figure 12; Figure 14 is a perspective view of a known clock provided with a silent alarm; and Figure 15 is a partial sectional view of a known wrist watch provided with a silent alarm. In Figure 1 there is shown an apparatus according to the present invention which is constituted by a wrist watch. The wrist watch of Figure 1 has a vibrator 1 which has a piezo-electric element 2 fixed thereon and which is supported by a pin or support shaft 4 that is mounted in a vibrator support plate 3, the pin 4 being substantially perpendicular to a back cover 17 of the wrist watch. The piezo-electric element 2 is adapted to generate a surface wave in the vibrator 1. An eccentric weight wheel or rotor 5 is mounted for rotation about the pin 4 as a centre and has a semi-circular arcuate eccentric weight portion 5a disposed radially outwardly of comb teeth la of the vibrator 1. Thus the eccentric weight portion 5a has a centre of gravity eccentric to the centre of the wheel 5. The eccentric weight wheel 5 is urged into contact with the comb teeth la of the vibrator 1 by a pressurizing spring 6. The pressurising spring 6 is held by a holding washer 7 which is secured to the pin 4 by a screw 8. The eccentric weight wheel 5, which is adapted to be driven by the said surface wave, works as a rotor of an ultrasonic wave motor. Figure 2 shows a plan view of the eccentric weight wheel 5. The eccentric weight wheel 5 has a substantially semi-circular arcuate shape. Another eccentric weight wheel is shown in Figure 3. In this embodiment, the eccentric weight wheel 5 has an arcuate fan shape to produce the same effects as those of the semi-circular weight. Returning to Figure 1, the eccentric weight wheel 5 extends through a hole 9a formed in a dial plate 9 so as to extend in the direction of a watch glass 10. The vibrator support plate 3 is secured to a main plate 11 by the screw 8a. An hour wheel 12 and a minute wheel 13, which are supported by the main plate 11 and by a wheel train bridge 14, are provided with an hour hand 15 and a minute hand 16, respectively. The back cover 17 referred to above is the same as that of an ordinary timepiece, the back cover 17 and the glass 10 defining the case of the wrist watch. Disposed within the said case 10, 17 of the wrist watch are electronic means (not shown) for driving the hands 15, 16 so as to indicate the present time and for transmitting an electrical signal to the piezo-electric element 2 so as to cause vibration of the latter at a selected alarm time. Means (not shown) are disposed within the case 10, 17 for coincidence between an alarm time (which is set by means not shown) and the present time and for transmitting the said electrical signal when such coincidence occurs. Figure 4 is an external plan view of the wrist watch of Figure 1. The dial plate 9 has a viewing window 9b in the lower portion thereof The eccentric weight wheel 5 is located in the window 9b and may be viewed through it. In operation, when an electrical signal is applied to the piezo-electric element 2, the vibrator 1 undergoes mechanical vibration which causes the eccentric weight wheel 5 to rotate. Therefore, the centre of gravity G of the eccentric weight portion 5a, whose position is spaced from the axis of rotation of the eccentric weight wheel 5, causes the whole wrist watch to be vibrated by the reaction and the energy of vibration is transmitted to the wrist of the user to provide an alarm. In this case, the wrist watch is vibrated as a result of the rotation of the eccentric weight wheel 5. The back cover 17, which is in contact with the wrist of the user, is substantially fixed in position and a large amplitude is therefore produced in the direction of the glass 10. Therefore, the moment for producing the vibration becomes greater in the direction of the glass 10 as the distance between the eccentric weight wheel 5 and the back cover 17 increases. When the distance between the back cover 17 and the centre of gravity G of the eccentric weight portion 5a is denoted by h, in the case when the eccentric weight portion 5a is contained in the movement and the distance in the case of this device is denoted by H, H >> h and the vibration is generated efficiently. In the embodiment of Figures 1-4, an ultrasonic wave motor which is used as a drive source is constituted by stacked plate-like members in contrast to an ordinary cylindrical electromagnetic motor. Such an ultrasonic wave motor therefore has a reduced thickness such that the wrist watch itself can be given a reduced thickness. Furthermore, the ratio H/h becomes great, so enabling the vibration efficiency to be improved. However, the drive source need not be limited to an ultrasonic motor but may be an ordinary electromagnetic motor in which the same effect can be produced of bringing the eccentric weight portion 5a close to the dial plate 9. The motion of the eccentric weight wheel 5 cannot be seen from the exterior of the wrist watch when it is contained in the movement. As shown in Figures 1 and 4, however, the motion of the eccentric weight wheel 5 can be seen directly if it is located on the front side of the dial plate 9. The alarm therefore can be provided visually in addition to being provided in the form of vibration. Figures 5 and 6 illustrate another embodiment of the present invention wherein a pin 4 is driven into a main plate 11c and is secured thereby. The vibrator 1, on which the piezo-electric element 2 is fixed, is secured to the pin 4c. A transmission wheel support member 23, which rotatably supports a transmission wheel 22 by means of a wheel guide pin 24, is fitted to the pin 4c in order to rotatably support a rotor 18. The rotor 18 has a gear portion 18a that meshes with the transmission wheel 22. The rotor 18 is supported by a pressurizing spring 6c which is urged into contact with a comb-toothed portion 1a of the vibrator 1. The pin 4c rotatably supports an eccentric weight wheel 5 which is retained in position by a washer 19 mounted on a reduced diameter portion 4a of the pin 4c. The eccentric weight wheel 5 has a gear 5c engaging with the transmission wheel 22, the centre of gravity of an eccentric weight portion 5a of the wheel 5 being spaced from the axis of rotation of the latter. In operation when the alarm is to be operated, the piezo-electric element 2 is vibrated due to an electric current that is transmitted thereto. The vibration that is generated in the piezo-electric element 2 is then transmitted to the vibrator 1 and is amplified by a comb-toothed portion 1a thereof. The rotor 18 is rotated by the comb-toothed portion 1a with the support pin 4c acting as a centre of rotation, and the transmission wheel 22 is rotated by a gear formed on the rotor 18. The transmission wheel 22 causes the eccentric weight wheel 5 to rotate about the pin 4c as a centre of rotation. The unbalanced centrifugal force produced by the rotation of the eccentric weight wheel 5 is transmitted through the main plate 11c to vibrate the whole timepiece. Even when the timepiece has an increased weight as a whole, the wheel train 18a, 22, 5c in this case increases the speed of rotation; i.e. the number of revolutions of the eccentric weight wheel 5 is increased and the unbalanced centrifugal force can be increased. Another embodiment of the present invention is shown in Figures 7 and 8. In this embodiment, the vibrator 1 on which the piezo-electric element 2 is fixed is supported by a pin 4d which is mounted in a wheel train bridge 14d. A rotor 18d is in the form of a disc without an eccentric weight and is urged into contact with the vibrator 1 by a pressurizing spring 6d mounted on a stop ring or washer 19d. A gear is formed along the periphery of the rotor 18d and is in mesh with an eccentric weight wheel 5d that is constituted by a shaft mounted separately from the pin 4d. The eccentric weight wheel 5d is supported by a main plate 11d and by the wheel train bridge 14d. A shaft portion 5b of the eccentric weight wheel 5d protrudes to the front of the watch and extends through a dial plate gd. To an end portion of the shaft portion 5b there is secured an eccentric weight 15a that has a centre of gravity at a point G. In other respects, the device is the same as that of Figures 1 and 2. In this case, the effects that are obtained are the same as those of the embodiment of Figure 1 without the need to form in the dial plate 9 a hole 9a whose size is greater than that of the eccentric weight 5a. In the case of the Figure 7 construction, the size of the hole in the dial plate 9d merely needs to be large enough for the shaft portion 5b to pass therethrough. Therefore, the dial plate 9 requires little processing and can be easily machined so as to provide a better appearance. Furthermore, the rotation is transmitted at an increased speed via gears, making it possible to generate stronger vibration. Figures 9 and 10 illustrate a further embodiment of the present invention. In this embodiment, the hour wheel 12 and the minute wheel 13 are supported by the main plate 11 and by the wheel train bridge 14, and the hour hand 15 and the minute hand 16 are driven so as to indicate the time. A pin 4e is driven into the back of a plate 11e which is carried by the main plate 11 so as to support the vibrator 1 on which the piezo-electric element 2 is fixed. On the pin 4e is mounted a rotor 18e. A pressurizing spring 6e and a stop ring 19e are provided beneath the rotor 18e to urge the latter into contact with the vibrator 1. A gear is formed along the circumference of the rotor 18e and is in mesh with an eccentric weight wheel 5e. The eccentric weight wheel 5e is rotatably mounted on a centre pipe or tube 20 whcih is mounted in the main plate 11. The eccentric weight wheel 5 is held between the main plate 11 and the dial plate 9 by means of a dial washer 21. The eccentric weight wheel 5e has a tubular portion 15b which extends towards the front side of the watch and passes through the dial plate 9. The tubular portion 15b has at one end thereof an eccentric weight 5a that has a centre of gravity at a point G. The back cover 17 and the glass 10 are constituted in the same manner as those of ordinary wrist watches. The watch of Figures 9 and 10 works similarly to that of Figure 1. However, since the eccentric weight wheel 5e is provieed concentrically with the hand wheels 15, 16 at the centre of the movement, the watch has an orthodox appearance. Figure 11 illustrates a still further embodiment of the present invention. In this embodiment, a centre pipe or tube 20f is mounted in the wheel train bridge 14. A minute wheel 13 is mounted concentrically about the centre tube 20f, and an hour wheel 12f is mounted concentrically about the minute wheel 13f. The hour wheel 12f and minute wheel 13f are held between the wheel train bridge 14 and the main plate 11 by means of a dial washer 21. An eccentric weight wheel 5f is mounted on the inner periphery of the centre tube 120 and is supported by a stop ring 19f. A pin 4f is driven into the main plate 11 on the upper side thereof to support the vibrator 1 and to carry a rotor 18f. The rotor 18f and the eccentric weight wheel 5f are in mesh with each other via gears that are formed along the circumferences thereof. In other respects, the watch is the same as that of Figure 5 and has the same advantages but the eccentric weight 5a is on the opposite side of the hour hand 15 and minute hand 16. Therefore, the alarm can be seen visually in an easily recognizable manner. Furthermore, the distance H between the back cover 17 and the eccentric weight 5a is increased, so contributing to an improvement in vibration efficiency. The motor 1, 2, 18f is disposed on the upper side of the main plate 11 and does not extend downwardly thereof. Therefore, the main plate 11 can be machined easily, so facilitating assembly. Figures 12 and 13 illustrate yet a further embodiment of the present invention. An hour wheel 12g is in mesh with a rotor 18g of the wave motor, the rotor 18g being mounted on a pin 4g which is fixed in a plate 11g carried by the main plate 11. A minute wheel 13g is driven by a separately provided motor (not shown) for driving the hands, the hour wheel 12g and the minute wheel 13g being driven independently of each other. An hour hand 15g is secured to one end of the hour wheel 12g and is so shaped in plan that its centre of gravity is at a position G which is spaced from its axis of rotation as shown, for example, in Figure 13, in order to produce the effect of an eccentric weight. Usually, therefore, the time is indicated by the outer end of the hour hand 15g. When the alarm set point time is however, reached, there will be high speed rotation of the hour hand 15g to generate vibration which provides the alarm. After the alarm has been provided, the hour hand 15g once again indicates the time. In this case, a large amount of energy is required to drive the hour hand 15g which has a large moment of inertia. From the viewpoint of construction, however, the number of parts can be decreased and the thickness of the timepiece can also be greatly decreased. Alternatively, the watch of Figures 12 and 13 may employ an ordinary hour hand and a minute hand (not shown) which acts as an eccentric weight. In the embodiments described above, the eccentric weight wheel is driven by the vibration of the vibrator to which a piezo-electric element is fixed,and the whole timepiece is vibrated by the unbalanced centrifugal force produced by the rotation of the rotor. Therefore, a wrist watch with a silent alarm is achieved which has a simplified construction, a small size and a reduced thickness. Moreover, the number of parts is decreased so as to reduce the manufacturing cost. Furthermore, the rotary shaft of the eccentric weight extends through the dial plate and the eccentric weight may be disposed on the front side of the dial plate, making it possible to transmit the energy of vibration to the wrist of the user while employing only a small amount of drive energy. Moreover, a visual alarm can also be provided so enabling a wrist watch with a silent alarm to exhibit greatly improved ability for letting the user be aware of the alarm. The apparatus of the present invention may also be constructed in credit card size form rather than in the form of a wrist watch so that it can be carried in the pocket.

Claims: An electronic apparatus having a case (10,17) within which there are rotatably mounted an eccentric weight (5a), a motor (1,2) for effecting rotation of the eccentric weight (5a) at an alarm information so as to cause vibration of the eccentric weight (5a) and thereby provide an alarm, and control means for operating the motor (1,2) at the alarm information characterized in that the motor (1,2) is an ultrasonic wave motor which comprises a vibrator (1) having a piezo-electric element (2) fixed to one side thereof for generating a surface wave thereon, a rotor (5,18) in contact with the opposite side of the vibrator (1), a pressure-regulator (6) for generating suitable contact pressure between the vibrator (1) and the rotor (5,18), and a support shaft (4) extending substantially perpendicular to a back cover (17) of the case, the support shaft (4) supporting the vibrator (1), and the rotor (5,18) being rotatably mounted on the support shaft (4). An electronic apparatus as claimed in claim 1 characterised in that the eccentric weight (5a) is connected to the rotor (5,18) and has a centre of gravity eccentric to the centre of the rotor (5,18). An elecctronic apparatus as claimed in claim 1 characterised in that the eccentric weight (5d) drives the rotor (18d) by way of gearing (18a, 22, 5c). An electronic apparatus as claimed in claim 3 characterised in that the eccentric weight (5) is mounted for rotation about an axis (5b) which is radially spaced from that of the rotor (18d). An electronic apparatus as claimed in any preceding claim characterised in that the apparatus has time indicating hands 915,16) which are concentric with the axis of the eccentric weight (5e). An electronic apparatus as claimed in claim 1 characterised in that the eccentric weight (15g) constitutes or forms part of a time indicating hand of the apparatus. An electronic apparatus as claimed in any preceding claim characterised in that means (9a) are provided to allow the eccentric weight (5) to be seen from the exterior of the case (10,17).

Inventors: KAWATA MASAYUKI, TSUKADA NOBUO, KAWATA, MASAYUKI, TSUKADA, NOBUO
Applicants: SEIKO INSTR INC, SEIKO INSTRUMENTS INC.
Application year: 1989
Main classification: G04C21
IPC codes: G04G1, G04C21, G04G13