GB1568048A - Alarm mechanism for a timepiece - Google Patents

Description

(54) ALARM MECHANISM FOR A TIMEPIECE (71) We, SEIKO KOKI KABUSHIKI KAISHA, a Japanese body corporate, of 3-1, 4-chome, Ginza, Chuo-ku, Tokyo, Japan, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to an alarm mechanism for a timepiece and, although the invention is not so restricted, it is more particularly concerned with a clock provided with a so-called "snooze device," i.e. with means for producing a second alarm a short time after the operation of a first alarm, so as to permit the user to "snooze" between the first and second alarms.

Previously known "snooze devices" has been of complicated construction, and have been large and expensive.

According to the present invention, there is provided an alarm mechanism for a timepiece comprising first and second time wheels which respectively drive analogue time indicator members; first and second detecting wheels which are arranged to detect the angular positions of the first and second time wheels respectively; setting means for setting the first and second detecting wheels in angular positions corresponding to a desired alarm time; means for producing an alarm indication when the angular positions of the first and second time wheels simultaneously correspond to those of the first and second detecting wheels; and a manually operable member which is separate from said setting means and operation of which adjusts the angular position of the second detecting wheel through a predetermined angle, operation of said manually operable member when the said alarm indication has been given causing the alarm indication to be temporarilv cancelled and a second alarm indication to be given after a predetermined length of timc.

Preferably, the means for producing an alarm indication comprise an electrical circuit having a switch therein constituted by relatively sliding electrically conductive parts carried by or integral with the second time wheel and the second detecting wheel respectively.

The setting means may comprise a single setting wheel which directly or indirectly engages with both the said detecting wheels.

The manually operable member is preferably movable between an inoperative and an operative position each movement of the manually operable member between the inoperative and the operative positions causing the second detecting wheel to be moved through the said predetermined angle. Thus the arrangement may be such that the manually operable member can be successively moved between its inoperative and operative positions a number of times in each of which the second detecting wheel is moved through the same angle.The manually operable member is preferably a lever which is pivotally urged towards an inoperative position in which it is spaced from a toothed member which is secured to or integral with the second detecting wheel, the lever being manually movable into an operative position in which the lever, or means carried thereby, engages the toothed member and turns the latter through one tooth pitch.

In one embodiment. a minute alarm signalling time indicating wheel may be provided with minutes indicia, the minute alarm signalling time indicating wheel having a drive connection with the second detecting wheel.

In another embodiment, the setting means has a knob provided with an index movable with respect to minutes indicia.

The first detecting wheel may be provided with an index for indicating the alarm signalling time.

The invention also comprises a timepiece provided with an alarm mechanism as set forth above.

The invention is illustrated, merely by way of example, in the accompanying drawings, in which:- Figure 1 is a broken away cross sectional view of a first embodiment of a clock provided with an alarm mechanism according to the present invention; Figure 2 is a plan view of a part of the structure shown in Figure 1; Figure 3 is a broken away cross sectional view of a second embodiment of a clock provided with an alarm mechanism according to the present invention; Figures 4 and 5 are plan views of parts of the structure shown in Figure 3; Figure 6 is a broken away cross sectional view of a third embodiment of a clock provided with an alarm mechanism according to the present invention; and Figure 7 is a plan view of a part of the structure shown in Figure 6.

Terms such as "left", "right," and "lower" as used in the description below, are to be understood to refer to directions as seen in the accompanying drawings.

Referring first to the embodiment shown in Figures 1 and 2, an alarm clock has a case 1 made of plastics material. The case 1 has at its left hand end a projection la having a tapped hole 1d therein. The case 1 also has holes 1e, of for rotatably mounting a tubular member 12a of an hour wheel 12 and an alarm signalling time setting wheel 18 respectively. The case 1 additionally has a boss 1b for rotatably mounting the lower end of a shaft 14a of a time indication adjusting wheel 14 and a boss 1g for mounting a shaft 2a on which there is rotatably mounted an intermediate hour wheel 11.

A middle frame 2 made of plastics material has a hole 2b for rotatably mounting an intermediate shaft 7, and a hole 2c for rotatably mounting a boss of a minute wheel 9. The middle frame 2 also has holes 2d, 2e through which the shafts of the alarm signalling time setting wheel 18 and the time indication adjusting wheel 14 pass freely.

The shaft 2a may if desired be integral with the middle frame 2.

A cover 3 which is also made of plastics material has holes 3a, 3b, 3c,d 3d for rotatably mounting a shaft 6 of a seconds wheel 5, the intermediate shaft 7, the shaft 14a of the time indication adjusting wheel 14, and the alarm signalling time setting wheel 18 respectively.

The middle frame 2 and the cover 3 are fastened to the case 1 at the projection la by means of screws 4.

The seconds wheel 5 is made integrally with a pinion Sa of plastics material. The seconds wheel 5 is fixed to the shaft 6 which is itself rotatably mounted in the hole 3a in the cover 3, the shaft 6 being provided at its lower end with a seconds hand 33. The shaft 6 is also rotatably mounted in a tubular member 9b forming part of the minute wheel 9. A minute hand 10 is fixed to the lower end of the tubular member 9b.

The seconds wheel 5 is driven by a motor, e.g. a stepping motor, not shown. The intermediate shaft 7 is made of plastics material and comprises an integral pinion 7a at its lower end. The intermediate shaft 7 has an integral first flange 7b, an integral second flange 7d, and an annular groove 7c therebetween. The upper end of the intermediate shaft 7 is rotatably mounted in the hole 3b in the cover 3, the central part of the intermediate shaft 7 being rotatably mounted in the hole 2b in the middle frame 2.

An intermediate wheel 8, which meshes with the pinion Sa of the seconds wheel 5, is rotatably mounted on the first flange 7b of the intermediate wheel 7 and is pressed against the latter by a leaf spring 32. A central portion of the leaf spring 32 bears against and is retained by the second flange 7d so that the intermediate wheel 8 and the intermediate shaft 7 are frictionally coupled together.

A gear portion 9c of the minute wheel 9 meshes with the pinion 7a of the intermediate shaft 7. The minute wheel 9 is made of electrically non-conductive plastics material and is integral with a pinion 9a and with the tubular member 9b. The upper end of the tubular member 9b is rotatably mounted in the hole 2c in the middle frame 2 and the lower end of the tubular member 9b is rotatably mounted in and extends through the tubular member 12a of the hour wheel 12.

The intermediate hour wheel 11 meshes with the pinion 9a of the minute wheel 9 and is made of plastics material integrally with a pinion Ila. The intermediate hour wheel 11 is rotatably mounted on the shaft 2a of the middle frame 2.

A gear portion 12b of the hour wheel 12 meshes with the pinion lia. The hour wheel 12 is made of electrically non-conductive plastics material integrally with the tubular member 12a in which is rotatably mounted the tubular member 9b of the minute wheel 9. The tubular member 12a is rotatably mounted in and extends through the hole le of the case 1 and has fixed to its lower end an hour hand 13.

The time indication adjusting wheel 14 also meshes with the intermediate hour wheel 11. The time indication adjusting wheel 14 and its shaft 14a are made integrally of plastics material. The lower end of the shaft 14a is rotatably mounted in a hole in the boss 1b of the base 1, while a central part of the shaft 14a extends freely through the hole 2e in the middle frame 2. The upper end of the shaft 14a is rotatably mounted in the hole 3c in the cover 3 and is fixed to a knob 15.

A minute detecting wheel 16 made of electrically conductive material is arranged to detect the angular position of the minute wheel 9 and is rotatably mounted on the tubular member 9b of the wheel 9 between the gear portion 9c of the minute wheel 9 and the gear portion 12b of hour wheel 12.

An hour detecting wheel 17 made of electrically conductive material is disposed directly under the gear portion 12b of hour wheel 12 and is arranged to detect the angular position of the latter. The hour detecting wheel 17 is rotatably mounted on the tubular member 12a of the hour wheel 12a.

The alarm signalling time setting wheel 18 is a compound wheel made of plastics material integrally with a first pinion 18a which meshes with the minute detecting wheel 16, and with a second pinion 18b which meshes with the hour detecting wheel 17, the alarm signalling time setting wheel 18 also having a third pinion 18c. The upper end of the alarm signalling time setting wheel 18 extends through the cover 3 and has fixed thereto a knob 19 to facilitate the alarm signalling time setting operation.

The hour detecting wheel 17, the gear portion 12b of the hour wheel 12, the minute detecting wheel 16 and the gear portion 9c of the minute wheel 9 are successively arranged axially of each other.

The third pinion 18c meshes with a minute alarm signalling time indicating wheel 20 which is rotatably mounted in the case 1.

The minute alarm signalling time indicating wheel 20 comprises a disc 20d having indexing teeth 20a and a stepped part 20e.

Minute alarm signalling time marks 20c (such as 0, 5, 10 ..... 55) are marked on the front face of the disc 20d so as to be visible through an alarm signalling time indicating opening 30a in a plate 30b secured to the case 1. The minute alarm signalling time indicating wheel 20 also has a locking wheel 20b, the locking wheel 20b meshing with a "click" or spring 29 fixed at one end of the case 1. The number of teeth of the locking wheel 20b corresponds to the number of minute marks 20c. Therefore the minute alarm signalling time indicating wheel 20 is "dick-stopped" at every minute mark 20c.

An hour alarm signalling time indicating wheel 21 is rotatably fitted on a stud lc extending from the lower surface of the case 1. The hour alarm signalling time indicating wheel 21 has a gear 21a meshing with the indexing teeth 20a of the minute alarm signalling time indicating wheel 20. The hour alarm signalling time indicating wheel 21 is provided with hour alarm signalling time marks 21b (e.g. 1, 2, 3 ..... 12) on its front face. Thus the user can visually set the alarm signalling time by rotating the setting knob 19 while observing the time marks 20c, 21b.

One terminal of a buzzer B is connected to the negative terminal of a battery E through the medium of a manual switch SW which is operable by an alarm signalling setting knob 23, while the other terminal of the buzzer B is connected to a first stationary contact plate 22. The switch SW is closed when the alarm signalling setting knob 23 is turned to render the alarm operable.

The first stationary plate 22 which is disposed between the case 1 and the hour detecting wheel 17, is fixed to the case 1.

The tubular member 12a of the hour wheel 12 extends through a central hole in the first stationary contact plate 22.

The hour detecting wheel 17 is made of electrically conductive material and has, on its lower face, three first projections 17a arranged on a common circle at equal angular intervals. On the upper face of the hour detecting wheel 17 there are three second projections 17b which are arranged on three different circles at equal angular intervals. The hour detecting wheel 17 is therefore always electrically connected to the first stationary contact plate 22 and is horizontally positioned by the contact between the first projections 17b and the first stationary contact plate 22.

An hour switch plate 24 is fixed to the upper face of the gear portion 12b of the hour wheel 12, and is disposed above the hour detecting wheel 17. The hour switch plate 24 has an upwardly extending slide contact member 24a which is always in sliding contact with the minute detecting wheel 16, the hour switch plate 24 being made of electrically conductive material.

The hour switch plate 24 has three downwardly projecting slide contact members of projections 24b which correspond to the second projections 17b of the hour detecting wheel 17 and which are arranged on three different circles at equal angular intervals.

Each projection 24b extends through a hole in the gear portion 12b of the hour wheel 12 so as to be engageable with the tip of the respective second projection 17b, the projections 24b extending substantially to the plane of the bottom face of the hour wheel 12.

Normally, the second projections 17b of the hour detecting wheel 17 slide on the bottom face of the hour wheel 12 so that the hour switch plate 24 and the hour detecting wheel 17 are electrically disconnected. The projections 24b and the second projections 17b of the hour detecting wheel 17, however, come in contact once every twelve hours at a predetermined relative positioning of the parts, and this contact is maintained for a fixed period of time. Thus the hour detecting wheel 17 and the hour switch plate 24 are electrically connected only when they are in predetermined relative positions.

The upwardly extending sliding contact member 24a of the hour switch plate 24 is always in sliding contact with and thus electrically connected to the electrically conductive minute detecting wheel 16. An insulating plate 25 and an electrically conductive sector-shaped switch plate 26 are assembled on and fastened together on the minute detecting wheel 16 by means of deformation or caulking so that the minute detecting wheel 16 and the sector-shaped switch plate 26 are electrically connected.

An electrically conductive minute switch plate 27 has a side contact part 27a extending downwardly through a hole in a gear portion 9c of the minute wheel 9. The slide contact part 27a is contactable with the sector-shaped switch plate 26, the switch plate 27 being fixed on the minute wheel 9 which is made of plastics material.

Normally, the minute contact plate 27 and the sector-shaped switch plate 26 are electrically disconnected as the slide contact part 27a slides over the insulating plate 25.

However, the parts 26, 27 are electrically connected once every hour for a certain period of time.

On the middle frame 2, there is fixed a second stationary contact plate 28, the left hand end of which is always in sliding contact with the upper face of the minute switch plate 27. and the right hand end of which is connected to the positive terminal of the battery E.

Although the alarm signalling time is indicated digitally. the angular position of the hour detecting wheel 17 is determined analogically as the hour detecting wheel 17 and the minute detecting wheel 16 are directly engaged with the alarm signalling time setting wheel 18. Therefore, even if the alarm signalling time is set at a time near the hour, such as 55 minutes, when the hour indication is about to change, the alarm signalling will be performed precisely at the preset alarm signalling time since the hour detecting wheel 17 is turned analogically to the angular position corresponding to 55 minutes, the hour switch plate 24 being so designed as to be in contact with the hour detecting wheel 17 for less than one hour, for instance 30 minutes.This will be so even if the minute switch plate 27 and the sector-shaped switch plate 26 are arranged to be in contact with each other for a fixed period of time such as 5 minutes or 10 minutes.

Fitted on the insulating plate 25 is a ratchet wheel 34 provided with twelve teeth 34a. The pitch of the teet 34a is such that, when the ratchet wheel 34 is turned through one tooth pitch, the minute detecting wheel 16 is turned through an angle corresponding to that through which it turns in the course of five minutes.

A "snooze" lever 35 is pivoted on a projection Id formed integrally on the case 1, the "snooze" lever 35 being urged counter-clockwise by a spring 36 towards engagement with a pin le.

On one end of the "snooze" lever 35 there is pivoted on a pin 35a a "click" or spring lever 37 which is urged counterclockwise by a spring 38. As will be seen from Figure 2, the "snooze" lever 35 is normally pivotally urged by the spring 36 to an inoperative position in which both itself and the lever 37 are spaced from the ratchet wheel 34. However, the lever 35 is manually movable into an operative position (not shown) in which the lever 37 engages the ratchet wheel 34 and such movement turns the latter through one tooth pitch.

In operation, the minute alarm signalling time indicating wheel 20 is adjusted by manual rotation of the alarm signalling time setting knob 19, the wheel 20 "clickstopping" at every minute mark 20c. The hour alarm signalling time indicating wheel 21 is rotated through an angle of 30 by the minute alarm signalling time indicating wheel 20 whenever the minute alarm signalling time indicating wheel 20 rotates from 55 to 00 or from 00 to 55, so that the hour alarm signalling time indicating wheel 21 is rotated through an angular distance corresponding to one hour. An operator can set the alarm signalling time while observing the marks 21b and 20c in the opening 30a.

Thus the angular position of the minute detecting wheel 16 and of the hour detecting wheel 17, that is the angular positions of the sector-shaped switch plate 26 and of the second projections 17b, will be determined by the operation of setting the alarm signalling time.

The manual switch SW is now closed by turning on the alarm signalling system setting knob 23. At this moment, the buzzer B will not, however, be actuated as neither the sector-shaped switch plate 26 and the slide contact part 27a. nor the second projections 17b of the hour detecting wheel 17 and the projections 24b of the hour switch plate 24 will be electrically connected.

The minute wheel 9 and the minute switch plate 27 rotate at the rate of one turn per hour, while the hour wheel 12 and the hour switch plate 24 rotate at the rate of one turn per twelve hours. Although the minute detecting wheel 16 and the hour detecting wheel 17 are urged to turn by frictional torque introduced by rotation of the corresponding switch plates 24 and 27, they are retained stationary in the angular positions to which they have been turned by the knob 19 as a result of the action of the "clickstopping" spring 29 on the minute alarm signalling time indicating wheel 20.

Althought the minute switch plate 27 and the sector-shaped switch plate 26 are electrically connected once an hour, the buzzer will not be actuated until the hour switch plate 24 and the hour detecting wheel 17 are also electrically connected at the same time.

As time passes, the angular positions of the projections 24b of the hour switch plate 24 and the second projections 17b of the hour detecting wheel 17 become synchronised so that the hour switch plate 24 and the hour detecting wheel 17 come into electrical contact. Such contact is maintained for a period of 20 to 40 minutes during which the minute switch plate 27 and the sectorshaped switch plate 26 come into electrical contact. Then the electrical circuit comprising the first stationary contact piece 22, the hour detecting wheel 17, the hour switch plate 24, the minute detecting wheel 16, the sector-shaped switch plate 26 and the second stationary contact piece 28 is completely closed so that the buzzer B is actuated.

The buzzer B can be stopped by opening the manual switch SW by means of the alarm signalling setting knob 23. The length of duration of buzzing can be determined as desired by appropriately designing the contact dimensions of the sector-shaped switch plate 26.

When the buzzer is actuated, the alarm signalling time can be reset so as to actuate the buzzer again five minutes later by a single clockwise movement of the "snooze" lever 35. Thus if the latter is moved clockwise in the direction of the arrow 35b shown in Figure 2, the lever 37 on the "snooze" lever 35 pushes the ratchet wheel 34 counter-clockwise, as indicated by arrow 34b, through an angle of 30 which corresponds to five minutes' advancement of the sectorshaped switch plate 26 relative to the minute switch plate 27. Thus when the angular position of the sector-shaped switch plate 26 is advanced by action of the "snooze" lever 35, the buzzer B stops as the sector-shaped switch plate 26 and the minute switch plate 27 are electrically disconnected.At the same time, the rotation of the insulating plate 25 is transmitted to the minute alarm signalling time indicating wheel 20 through the minute detecting wheel 16 and the alarm signalling time setting wheel 18 so that the alarm signalling time indication is advanced by five minutes. When the "snooze" lever 35 is released, it is returned to the initial position by the spring force, while the lever 37 is also returned to its initial position, passing over a tooth 34a. Five minutes after the resetting of the alarm signalling time, the sector-shaped switch plate 26 and the switch plate 27 come into electrical contact again due to the rotation of the minute wheel 9 through an angular distance corresponding to five minutes, so that the buzzer B is actuated again. Alarm signalling can be repeated every five minutes by the repetition of the resetting procedure as described above.

The manual switch SW must be turned off by the alarm signalling setting knob 23 if it is desired to disable the alarm signalling system.

The "snooze" device is operable to advance the alarm signalling time by 5, 10, 15 minutes, or the like by respectively pushing the "snooze" lever 35 once, twice, three times, or so on. The alarm signalling time indicating marks 20c and 21b appearing in the opening 30a are also changed according to the advancement of the alarm signalling time.

The rotation of the time adjusting knob 15 in either angular direction is transmitted to the minute wheel 9 and to the hour wheel 12 through the intermediate hour wheel 11.

Although the minute detecting wheel 16 and the hour detecting wheel 17 are urged to turn by frictional torque introduced by way of the switch plates 24 and 27, they are retained at the predetermined angular positions by the action of the "click-stopping" spring 29 on the minute alarm signalling time indicating wheel 20.

The rotation of the time adjusting knob 15 is transmitted also to the intermediate shaft 7 through the minute wheel 9 and the pinion 7a. Frictional torque applied to the intermediate wheel 8 by the leaf spring 32 fixed to the intermediate wheel 7 urges the intermediate wheel 8 to turn. however, reverse torque of the motor applied to the intermediate wheel 8 through the seconds wheel 5 and pinion 5a exceeds the frictional torque of the leaf spring 32, and the intermediate wheel 8 will therefore not be turned. Thus the adjustment of the angular positions of the minute hand and the hour hand is attained without affecting the angular positions of other components. Furthermore, every detecting switch of this embodiment is constituted by sliding contacts, while the time adjusting knob 15 may be turned either clockwise or counterclockwise.

In Figures 3 to 5 there is shown a second embodiment of this invention, in which the gear train for driving the time indicating system is substantially identical to that of the first embodiment. The alarm signalling time is indicated analogically by an index or pointer 140 fixed to the lower end of a tubular member 117a forming part of an hour detecting wheel 117. An alarm signalling time setting wheel 118, as in the first embodiment, is integral with a first wheel 118a, a second wheel 118b and "clickstopping" grooves 118c which engage with a "click-stopping" spring 129 fixed to a middle frame 102.

An alarm signalling time setting knob 119 is fixed to the upper end of the alarm signalling time setting wheel 118. An index 119a of the alarm signalling time setting knob 119 accurately indicates the minute portion of the alarm signalling time by pointing to a corresponding one of minute alarm signalling time marks 103d (Figure 4) provided on a cover 103.

The approximate alarm signalling time is set by observing the indication provided by the index 140 on the clock dial, and the minute place can be precisely determined by the indication provided by the index 119a of the alarm signalling time setting knob 119 which co-operates with the alarm signalling time marks 103d.

A ratchet wheel 134 is secured to an insulating plate 125, as in the first embodiment. A "snooze" lever 135 is pivoted on a projection of a case 101 and is urged counter-clockwise by a spring 136 (Figure 5) towards engagement with a pin 101e.

A "click" lever 137 is pivoted in a tight fit on a pin 135a on one end of the "snooze" lever 135. The ''click" lever 137 comprises a split spring boss 137a, a first arm 137b, and a second arm 137c which has a first projection 137d and a second projection 137e. The "click" lever 137 is allowed to swing within a limited range relative to the "snooze" lever 135 because the rotation of the first arm 137b is limited by two pins 135b fixed on the "snooze" lever 135.

In its resting position, the "snooze" lever 135 and the second arm 137c of the "click" lever 137 are stopped by the pins 101e and 101f respectively.

The embodiment of Figures 3 to 5 operates similarly to that of Figures 1 and 2.

Thus the buzzer (not shown) is actuated when all detecting switches are closed simultaneously. When the "snooze" lever 135 is pushed down, the first projection 137d of the "click" lever 137 is engaged with the ratchet wheel 134 and turns the ratchet wheel 134 30 counter-clockwise.

At the end of the rotation of the ratchet wheel 134, the second projection 137e comes into contact with a tooth of the ratchet wheel 134 so that motion of the ratchet wheel due to inertia is checked.

Thus, since the contact between a sectorshaped switch plate 126 and a minute switch plate 127 is cut off, the buzzer is stopped buzzing. The rotation of the ratchet wheel 134 is transmitted to the hour detecting wheel 117 so that the index 140 fixed on the tubular member 117a of the hour detecting wheel 117 is advanced five minutes. When the "snooze" lever 135 is released, it is returned to the original position by the spring 136 while the "click" lever 137, which is controlled by the pin 101f, returns to the original position.

In Figures 6 and 7 there is shown a third embodiment in which a middle frame 202 is provided at its left hand end with a projection 202b on the upper and lower ends of which a cover 203 and a printed circuit board 230 are respectively fixed by screws 204.

A gear train for driving the time indicating system is constituted similarly to that of the first embodiment and comprises a seconds wheel 205, an intermediate shaft, not shown, a frictional coupling, not shown, an intermediate wheel, not shown, a minute wheel 209, an intermediate hour wheel 211, and an hour wheel 212.

A second intermediate hour wheel 241 which is made of plastics material, rotates at the same rate as the intermediate hour wheel 211.

A minute detecting wheel 225 is disposed between the second intermediate hour wheel 241 and the printed circuit board 230.

An hour detecting wheel 217 is disposed between a gear portion of hour wheel 212 and the printed circuit board 230 and is fixedly provided with an index 232 at the lower end of its tubular member 217c.

A first wheel 218a, a second wheel 218b, and a ratchet wheel 218c are integral parts of an alarm signalling time setting wheel 218, the latter having an alarm time setting knob 219 fixed to the top thereof. The first wheel 218a and the second wheel 218b are engaged with a gear 234 and with the hour detecting wheel 217, respectively. A friction member 233, fixed on the middle frame 202 applies frictional torque of a fixed intensity to the ratchet wheel 218c so that the alarm signalling time setting wheel 218 is restrained from free rotation.

The following explanation is concerned with the constitution of the alarm signalling time detecting switches.

The printed circuit board 230 comprises a first printed pattern 230a and a second printed pattern 230b electrically connected with one terminal of a buzzer (not shown) and the positive terminal of an electric power source (not shown), respectively.

The hour detecting wheel 217 is, similarly to the first embodiment, made of electrically conductive material and is provided on its lower and upper surfaces with first projections 217a and second projections 217b, respectively.

The first projections 217a are always electrically connected to the first printed pattern 230a over which it slides. An hour wheel 212, made of plastics material, is fixedly provided with an hour switch plate 224 which has a projection 224b similar to that of the first embodiment. A contact sleeve 216 made of electrically conductive material is always in sliding contact with the second printed pattern 230b. A minute detecting wheel 225, which is made of electrically non-conductive material, and a sector-shaped switch plate 226 (Figure 7) which has three arms, are fixed to the contact sleeve 216 by means of deformation or caulking so as to electrically connect the sector-shaped switch plate 226 and the contact sleeve 216.A minute switch plate 227, which has a sliding contact piece 227a extending downwardly to enable it to contact the sector-shaped switchplate 226, is fixed to the second intermedate hour wheel 241 made of plastics material. The sliding contact piece 227a comes into contact with the sector-shaped switch plate 226 once every hour as the second intermediate hour wheel 241 rotates at the rate of 3 of the minute wheel 209. A first arm 228a and a second arm 228b of a forked stationary contact plate 228 are always in contact with the hour switch plate 224 and the minute switch plate 227, respectively, so that the hour switch plate 224 and the minute switch plate 227 are always electrically connected.

A "snooze" slide plate 235 is movable vertically as seen in Figure 7, being guided by guide pins 202c fixed on the middle frame 202 and being normally retained by a spring 236 at its upper position. A "click" lever 237 is pivoted on a pin 235a on the "snooze" slide plate 235.

The "click" lever 237 has a first arm 237a, a second arm 237b, and a downwardly elongated part 237c. The first arm 237a is in contact with a fixed pin 202d when the "click" lever 237 is at the rest position. The second arm 237b bears frictionally against the "snooze" slide plate 235 so that the "click" lever 237 is restrained from free rotation about the pivot 235a.

In operation, the alarm signalling time is set by a similar procedure to that of the second embodiment. The sector-shaped switch plate 226 of the minute detecting wheel and the second projections 217b of the hour detecting wheel are rotated to the correct angular positions, respectively, corresponding to the alarm setting time. This is effected by the alarm signalling time setting wheel 218 through the first wheel 218a and the second wheel 218b and the gear 234.

The alarm signalling time setting is completed by turning on the manual switch (corresponding to the switch SW of the first embodiment). Although the sector-shaped switch plate 226 and the minute switch plate 227 come into electrical contact three times every three hours, the buzzer (not shown) will not be actuated until the hour detecting wheel 217 and the hour switch plate 224 come into electrical contact. As time passes, the angular positions of the second projections 217b of the hour detecting wheel and the projection 224b of the hour switch plate are synchronised in the first place so that the hour detecting wheel and the hour switch plate are electrically connected for a certain period of time.When the sector-shaped switch plate 226 and the minute switch plate 227 are electrically connected during the time that the electrical connection of the hour detecting wheel and the hour switch plate is maintained, the electric circuit comprising the first printed pattern 230a, the hour detecting wheel 217, the hour switch plate 224, the stationary contact plate 228, the minute switch plate 227, the sectorshaped switch plate 226, the contact sleeve 216, and the second printed pattern 230b is closed to actuate the buzzer.

When the "snooze" slide plate 235 is pushed down, the downwardly elongated part 237c of the "click" lever 237 causes the ratchet wheel 218c to rotate counterclockwise. This rotation is transmitted to the minute detecting wheel 225 through the gear 234 to rotate the sector-shaped switch plate 226 counter-clockwise so that the sectorshaped switch plate 226 and the minute switch plate 227 are electrically disconnected and consequently the buzzer stops buzzing.

The "snooze" slide plate 235 is returned to its rest position by the spring 236 when it is released. The downwardly elongated part 237c is then turned clockwise to its rest position until the first arm 127a engages the fixed pin 202d. About five minutes after the actuation of the "snooze" slide plate, the sector-shaped switch plate 226 and the minute switch plate 227 are electrically connected again as a result of the advancement of the angular position of the second intermediate hour wheel 241, so that the buzzer is actuated again.

As will be appreciated. the newly reset alarm signalling time is indicated analogically by an index. or is indicated digitally by time mark wheels to facilitate precise conformation of the reset alarm signalling time when the alarm signalling time is reset at any desired time by repeating as often as desired the actuation of the "snooze" slide plate.

Attention is directed to our three copending British Patent Application Nos.

20454/78. (Serial No. 1566366) 21163/78 (Serial No. 1566367) and 21909/78 (Serial No. 1566368) which show similar constructions.

Claims (11)

WHAT WE CLAIM IS:

1. An alarm mechanism for a timepiece comprising first and second time wheels which respectively drive analogue time indicator members; first and second detecting wheels which are arranged to detect the angular positions of the first and second time wheels respectively; setting means for setting the first and second detecting wheels in angular positions corresponding to a desired alarm time; means for producing an alarm indication when the angular positions of the first and second time wheels simultaneously correspond to those of the first and second detecting wheels; and a manually operable member which is separate from said settingmeans and operation of which adjusts the angular position of the second detecting wheel through a predetermined angle, operation of said manually operable member when the said alarm indication has been given causing the alarm indication to be temporarily cancelled and a second alarm indication to be given after a predetermined length of time.

2. An alarm mechanism as claimed in claim 1 in which the means for producing an alarm indication comprise an electrical circuit having a switch therein constituted by relatively sliding electrically conductive parts carried by or integral with the second time wheel and the second detecting wheel respectively.

3. An alarm mechanism as claimed in claim 1 or 2 in which the setting means comprises a single setting wheel which directly or indirectly engages with both the said detecting wheels.

4. An alarm mechanism as claimed in any preceding claim in which the manually operable member is movable between an inoperative and an operative position each movement of the manually operable member between the inoperative and the operative positions causing the second detecting wheel to be moved through the said predetermined angle.

5. An alarm mechanism as claimed in claim 4 in which the manually operable member can be successively moved between its inoperative and operative positions a number of times in each of which the second detecting wheel is moved through the same angle.

6. An alarm mechanism as claimed in claim 4 or 5 in which the manually operable member is a lever which is pivotally urged towards an inoperative position in which it is spaced from a toothed member which is secured to or integral with the second detecting wheel, the lever being manually movable into an operative position in which the lever, or means carried thereby. engages the toothed member and turns the latter through one tooth pitch.

7. An alarm mechanism as claimed in any preceding claim comprising a minute alarm signalling time indicating wheel provided with minutes indicia, the minute alarm signalling time indicating wheel having a drive connection with the second detecting wheel.

8. An alarm mechanism as claimed in any of claims 1 to 6 in which the setting means has a knob provided with an index movable with respect to minutes indicia.

9. An alarm mechanism as claimed in any of claims 1 to 6 or 8 in which the first detecting wheel is provided with an index for indicating the alarm signalling time.

10. An alarm mechanism for a timepiece substantially as hereinbefore described with reference to and as shown in Figures 1 and 2, or in Figures 3 to 5, or in Figures 6 and 7 of the accompanying draw ings.

11. A timepiece provided with an alarm mechanism as claimed in any preceding claim.