US3643421A

US3643421A - Electric alarm clock with illuminable face

Info

Publication number: US3643421A
Application number: US861902A
Authority: US
Inventors: Friedrich Herr; Jurgen King
Original assignee: UHRENFABRISK SENDER GmbH
Current assignee: UHRENFABRISK SENDER GmbH
Priority date: 1968-09-28
Filing date: 1969-09-29
Publication date: 1972-02-22
Anticipated expiration: 1989-02-22
Also published as: AT300672B; FR1603915A; CH1468169A4; GB1253409A; DE1798352A1; CH517967A

Abstract

An electric alarm clock has an hour wheel which can move axially to engage with several teeth in an alarm-hour setting wheel and make an electrical contact therewith by means of a protruding metallic tongue on a conductive plate mounted on the nonconductive hour-wheel. This tongue makes a brief contact until further rotation of the hour wheel allows it to drop into the hole and open the circuit for the alarm. A second pair of contacts in series with the first-mentioned pair is closable on axial shifting of the hour-wheel into the alarm wheel. A contactbreaking arm of nonconductive material can be pushed between these second contacts and is clamped by them there until the hour-wheel is automatically cammed out of and away from the alarm wheel, whereupon the contact-breaking arm is released. Depression of a button on the clock lights a lamp for illuminating the clock dial face and can shift the contact-breaking arm toward the second contacts to open same. Means is provided to prevent pivoting of the contact-breaking arm between the contacts except when the teeth of the hour-wheel are engaged fully in the holes in the alarm wheel.

Description

United States Patent 151 3,643,421 Herr et al. Feb. 22, 1972 [54] ELECTRIC ALARM CLOCK WITH ILLUMINABLE FACE [72] Inventors: Friedrich Herr, Hubertusstrasse l, 7911,

wyi snfis l mliir su l Ei9h, tinghausstrasse, 7913 Senden/lller, both of Germany [73 Assignee: said Herr assor toj-Uhrenfabrisk Sender- GmbH, Sender/flier, Germany [22] Filed: Sept. 29, 1969 [21] Appl. No.: 861,902

[30] Foreign Application Priority Data Sept. 28, 1968 Germany ..P 17 98 352.7

[52] US. Cl ..58/50, 58/19, 58/23 [51] Int. Cl. ..G04b 19/34 [58] FieldofSearcln ..56/17, l9,20,2l.l2,21,38,

[56] References Cited I UNITED STATES PATENTS 3,386,238 6/1968 Voit ..58/50 Pn'mary Examiner-Richard B. Wilkinson Assistant Examiner-Edith C. Simmons Attorney-Karl F. Ross [5 7] ABSTTIACT An electric alarm clock has an hour wheel which can move axially to engage with several teeth in an alarm-hour setting wheel and make an electrical contact therewith by means of a protruding metallic tongue on a conductive plate mounted on the nonconductive hour-wheel. This tongue makes a brief contact until further rotation of the hour wheel allows it to drop into the hole and open the circuit for the alarm. A second pair of contacts in series with the first-mentioned pair is closerble on axial shifting of the hour-wheel into the alarm wheel. A contact-breaking arm of nonconductive material can be pushed between these second contacts and is clamped by them there until the hour-wheel is automatically cammed out of and away from the alarm wheel, whereupon the contactbreaking arm is released. Depression of a button on the clock lights a lamp for illuminating the clock dial face and can shift the contact-breaking arm toward the second contacts to open same. Means is provided to prevent pivoting of the contactbreaking arm between the contacts except when the teeth of the hour-wheel are engaged fully in the holes in the alarm wheel 26 Claims, 12 Drawing Figures PAIENIEBFEB22 m2 3.643.421

sum

1 or 7 Friedrich HERR marl 9.

ATTORNEY PATENTnFEa22 I972 3.643.421

sum

3 or 7 Fig. 2

Friedrich HERR Jurgcn KING Inventor s ATTORNEY PATENTEDFEBZZ m2 3. 643 .421

SHEET u 0F 7 4O 17 22 21 m I Fig. +b

Friedrich HERR Inryen VIN) Inventor 3 ATTORNEY PAIENTEBFEB 22 m2 SHEET 5 [IF 7 Fig. ha

Friedrich HERR Jurgen KING Inventors 9M ii ATTORNEY mwinrsazzm. 3.643.421

' Friedrich HERR Jurgen KING lnvntors acnllgi iRgu ATTORNEY ELECTRIC ALARM CLOCK WITH ILLUMINABLE FACE The present invention relates to an electrical alarm clock having an electrically illuminated dial.

Electric alarm clocks known in the art have the disadvantage that their mechanism is greatly complicated by the elements which limit the length of the alarm ringing or buzzing. The great complexity of these elements makes the clock more liable to breakdown while increasing its cost. What is more, such elements take up a good deal of space, thereby making them impractical for very small alarm clocks, such as the portable alarm clocks used on trips.

There is known an alarm clock whose alarm mechanism is actuated by a so-called centrifugal trip arrangement. The duration of the alarm is limited by a switch wheel which is actuated simultaneously with the above-mentioned element. Such an alarm clock has the disadvantage that the additional actuation of the switch wheel consumes a sizable amount of the clock drive energy while it causes a great deal of wear to the entire mechanism.

Many efforts to overcome these disadvantages have only resulted in further complication of the mechanisms of such clocks without producing a corresponding amelioration in the overall quality ofthe clock. I

In another well-known type of alarm clock the duration of the alarm is limited by a quick-running drive part of the movement of the clock. As soon as the alarm is actuated, a coupling connects in the quick-running drive mechanically with the electric clock movement so that when this drive finishes its cycle the alarm is stopped.

Such an arrangement often makes it impossible for the user to shut the alarm off himself without being obliged to actuate a switch in series with the alarm device. Of course, this additional switch constitutes only another fallible mechanism part. In addition, such a mechanism makes it easy to forget to reactivate the alarm for the next morning, so that often the clock is shut off and fails to operate the subsequent day.

Another known type of alarm clock has an actuating element which serves both to stop the alarm and to light a lamp which illuminates the face or dial of the clock. It was found, however, that when the user frequently wakes up and looks at the clock, actuating the button to illuminate the face, he periodically does this just at the moment when the alarm is supposed to sound. In this case, the alarm does not sound and the user is quite liable to go back to sleep without having been awakened.

It is, therefore, the general object of the present invention to provide an improved electric alarm clock.

A more specific object is to provide such an alarm clock which has a gear wheel which moves axially and thereupon triggers the alarm.

Another object is to provide such a clock which need not be periodically reset and which resets itself automatically.

Yet another object is to provide an alarm clock having a common actuating element for the dial illumination and for stopping the alarm which overcomes the disadvantages of the above-mentioned arrangements.

Thus, an object of the present invention is to provide an improved electric alarm clock which overcomes the abovedescribed specific disadvantages.

These objects are obtained, in accordance with features of the present invention, by an alarm clock having means for automatically resetting the alarm mechanism once the alarm has stopped sounding or otherwise signaling the user. The actuating element for stopping the alarm also serves to illuminate the dial face, but means is provided for preventing the actuating element from stopping the alarm from sounding if this element is actuated prior to the start moment of the alarm. (Although the alarm is here always referred to as some sort of acoustic signal, it is to be understood that any of a multitude of optical or tactile or other alarms are well within the scope of the invention.)

According to a particular feature of the invention, the hour wheel of the alarm clock serves to actuate a pair of series contacts which in turn trigger the alarm. One of the sets of contacts is closed by an axial shifting of the hour-wheel while the other set of contacts is closed by a rotation of this wheel. The above-mentioned actuating element is connected to an arrangement which simply opens one of these sets of contacts. The hour-wheel shifts axially toward the alarm set wheel to close all the contacts and is shifted axially away from this wheel by its own rotation to open them again and stop the alarm.

In accordance with another feature of the invention the hour-wheel slips axially toward the alarm-set wheel in two steps: a first step where it makes contact therewith and closes the one set of contacts, and a second step where it is shifted yet closer to the alarm-set wheel and opens this set of contacts. To this end the hour-wheel is molded of synthetic resin with at least one, preferably three, teeth on the face turned toward the alarm-set wheel. These teeth all have a straight flank directed away from the hour-wheel direction of rotation and a relatively shallow flank directed in the other rotational sense. The alarm-set disk is provided with matching openings in which the teeth can all engage simultaneously. The hour wheel is provided on the same face with a contact ring forming a contact tongue having an end extending substantially parallel toand slightly beyond one of the teeth. The alarm-set wheel is metallic so that when the teeth drop into the holes the tongue makes an electrical contact therewith, but when the rotation of the hour-wheel pulls this prestressed tongue into the hole the contact is broken.

The clock according to the invention having the above features has a minimal amount of moving parts which wear very little. At the same time it offers features of much larger and more costly clocks while itself being extremely small and relatively inexpensive to produce.

The above and other features, objects, and advantages will become more apparent from the following description, reference being made to the accompanying drawing, in which:

FIGS. la-1c show various views of an alarm clock according to present invention;

FIG. 2 is a rear elevational view of another embodiment of the alarm clock according to the present invention;

FIG. 3 is a section through a detail of the clock according to the present invention;

FIGS. 4a and 4b are views of the hour wheel of the clock according to the present invention;

FIGS. 5a through 5d are views through another detail ofthe alarm clock according to the present invention; and

FIG. 6 is a circuit diagram illustrating other features of the invention.

The embodiment shown in FIGS. la-lc is illustrated without many conventional items, drive, alarm devices, etc., for the sake of clarity; these elements are well known in the art and therefore do not need further description.

A front plate 1 (FIG. 16) mounts a minute shaft 2 rotatably on which a drive wheel 3 is mounted. A change wheel 4 engages this wheel 3 and is journaled in the plate 1 by means of a bolt 5. A pinion 6 formed unitarily with the change wheel 4 engages an hour wheel of the clock mechanism, the pinion 6 being axially long enough to engage the hour wheel even when this latter is shifted axially.

Another plate 8 carries the dial face 9 which has the clock numerals printed on it. A bushing 10 is mounted in this plate 8 and is formed with the wheel 11 and serves to mount the bushing 12 of an alarm-hour indicator 13.

The hour wheel 7 is carried on the bushing 14a which in turn carries an hour hand on its front end 15a. A leaf spring 14 fastened to the plate 1 urges the hour-wheel by means of a loop 15 in this spring against the alarm-hour indicator wheel 11. The hour wheel 7 has on its side toward this wheel 11 several toothlike camming formations 16 with one straight and one shallow flank each, which, when the predetermined time arrives, drop into correspondingly spaced holes on the plate I], pushed by the spring 14. This predetermined time is set by a control 17 cammingly engaging the teeth of the wheel ll.

The alarm-hour indicating wheel 11 bears with a circular ridge 18 on the front plate 8 of the clock so that an electrical connection is made between the two.

FIGS. 4a and 4b show the hour-wheel 7 in detail. There are shown two like, simple teeth 16, and a third tooth 19 having a radial protrusion 20. An annular contact disk 22 is formed with a tongue 21 which presses against the underside of the protrusion 20. The hour wheel 7 is formed with an annular depression in which this disk 22 is received. The disk 22 is formed with an inwardly projecting foot 23 which engages behind the tooth 19 while a plurality of clamping formations 24 prevent the disk 22 from rotating relative to the wheel 7. The tongue 21 is stamped out of the ring 22 which can be held on the wheel 7 by soldering, by welding or by rivets or screws; alternatively the tongue can be plated or laminated on the wheel 7.

Every 12 hours the three

teeth

16, 19 engage in the holes in the disk 11. First the two teeth 16 pass over their respective holes so that for a brief period the entire axial force of the spring 14 is taken up solely by the tooth 19. Then the tooth 19 engages in its hole, suddenly since its straight flank is the trailing one, and the tongue 21 comes to rest against the disk 11 with its end 25 which projects beyond the protrusion backwardly relative to the direction of rotation of the hour wheel 7. This forms an electrical contact between the ring 22 and the plate 8, via the tongue 21, the disk 11, and the ridge 18. The hour wheel 7 continues to turn until the tongue 21 drops into the hole and breaks contact. Thereafter the shallow flank of the tooth 19 and the teeth 16 cam the hour-wheel axially back to its illustrated in FIG. 1a. Thus, it is the arc length of the projecting end of the tongue 21 which determines the duration of the closed circuit which is used to electrically actuate the alarm. In this manner a very short, if desired, or reasonably long duration of alarm is easily obtainable. The

I hour-wheel 7 is formed with an axially projecting, circular ridge 26 to prevent the ring 22 from contacting the plate 11 even

whenthe teeth

16, 19 are fully engaged in the holes and before. the shallow flanks 28 of these teeth start camming the disk 7 to the right in FIG. 1b.

As is particularly well illustrated in FIGS. 5a-5d, two fingers 29 engage the top of the disk or hour-wheel 7 and one finger 30 engages under it, making an electrical contact with the contact ring 22 by means of a boss 41, a similar boss 40 being formed on each of the fingers 29. These

fingers

29 and 30 are formed unitarily of a piece of sheet metal having bent up tabs and an arm 31. A short rod 32 held at each end in small blocks 34 formed on a synthetic-resin body passes through the tabs 35 and allows the

fingers

29, 30 and the arm 31 to rock.

The arm 31 is formed on its free end with an eye 36 which is oval, as shown in FIGS. 1b, and has a bump 37. A metal plate 38 clipped through the body 33 as shown in FIGS. 5a and 5d has a connecting tab 39 and acts as a contact for the bump 37.

As the hour-wheel 7 rotates, the fingers 30 make contact with the contact ring 22, rubbing lightly thereon. When, as described above, the moment for the alarm to sound arrives and the hour-wheel 7 shifts toward the wheel 11, the

fingers

29 and 30 are entrained and the arm 31 is pivoted about the pin 32 which is clipped in keylike slots 68 in the blocks 34 and the bump 37 makes contact with the metal strip 38. During axial shifting of the hour-wheel 7 the

rounded bumps

40 and 41 on the

fingers

29 and 30 ride radially on the hour-wheel 7, with the finger 30 always making good contact with the contact ring 22. FIG. 5c shows in dot-dash lines the position of the arm 31 when the wheel 7 is not engaged with

teeth

16 and 19 in the disk 11. The deflecting formation 36 on the arm 31 is engageable with a contact-breaking arm or member 56 as will be described below.

This pair of

contacts

37 and 38 form the switch part of the alarm circuit which can be opened to cut off the alarm, even if the tongue 21 is still in contact with the disk 11. To this end an actuating element or button 42 is provided which is formed with an abutment 43 extending through a hole 46 in the plate 8. The element 42 is pivoted at and a spring 44 is engaged at one end in a hole 51 in the plate 8 and at the other end under a tab 52 on the element 42. This button or lever element 42 is also formed with an arm 47 fitted with a roller 48 engageable with a spring contact 49. The plate 8 is preferably grounded to one pole of a dry cell battery and the element 42 is preferably metallic so that when the roller 48 touches the contact 49 it grounds it. This contact 49 is advantageously connected to the lamp serving to illuminate the dial face so that grounding the contact 49 closes the circuit and lights the lamp. Thus, depression (the up direction in FIG. la) of the button 42 lights the lamp and illuminates the dial, at all times.

The abutment 43 of the lever 42 is connected to a spring 53 having an end 54 engaging a contacting-breaking lever 56 pivoted at 55 on the block 33. This lever 56 carries another spring 57 which engages an abutment 58 on the plate 8, and the lever 56 is of nonconducting synthetic-resin material. Thus, the spring 44 urges the lever 42, as seen in FIG. la in the clockwise direction and the spring 57 similarly urges the lever 56in this direction.

When the button 42 is depressed as described above, the spring 53 urges the lever 56 in the counterclockwise direction and forces it in between the

contacts

37 and 38. As shown in FIG. 10, the lever 56 is formed with a groove 61 next to a ridge 60 at its free end 59. In this manner, as the end 59 is pivoted between the

contacts

37 and 38, with them in their closed condition, the bump 37 engages in the groove 61 and behind the ridge 60 to hold the lever 56 therebetween, in spite of the spring 57. However, should the contacts be in the open position, the arm 56 will not catch and will simply return to its FIG. 1a illustrated position, due to the pressure exerted by the spring 57. The formation 36 serves, of course, to allow the contact arm 31 to be easily deflected by the lever 56.

In order to prevent the alarm from being prematurely cut off in case the user happens to turn on the light to look at the dial just at the moment the alarm is supposed to sound, the spring 14 is formed with an arm 62 having an end 63 in turn formed with a bent over depending tab 64 that engages through a hole 65 formed in the synthetic-resin body 33, as clearly shown in FIG. 10. As long as the hour wheel 7 is not engaged with its

teeth

6, 19 in the wheel 11, the spring 14 remains to the right in FIG. 1b and the tab 64 engages through the hole 65. Thus, if the button 42 is depressed while the hour wheel is out of engagement with the wheel 11, the tab 64 will prevent the lever 56 from slipping in between the

contacts

37 and 38. The spring 53 deforms to allow the button 42 to be depressed while the lever 56 merely engages the tab 64, swinging no further counterclockwise.

The spring tensions of

springs

54 and 14, along with the resistance to sliding friction of the tab 64 in the hole 65, and the resilience of the arm 31 are such that, should the button 42 be depressed and held with the tab 64 in place in the hole 65, and should at that moment the wheel 7 shift toward the wheel 11, the end 59 of the arm 56 will clamp the tab 64 in place, even though the spring 14 is exerting a force to pull it out. Thus, if the button is depressed to light the dial face just when the alarm is supposed to sound, this alarm will sound anyhow, and it will require release of the button 42 so that the lever 56 will free the tab 64 which will pull out of the hole 65 and another actuation of this button 42 to stop the alarm.

FIG. 2 shows an alternative embodiment of the present invention, common reference numerals referring to common structure. The arm 56' here is molded of synthetic resin unitarily with extensions forming springs 53' and 57. The bent extension 53 engages an abutment 43 formed on the actuating element 42. An abutment'58' formed on the plate 8 is engaged by the spring extension 57. Such a construction is extremely inexpensive and advantageous.

In addition, FIG. 2 shows that the spring 62 has an end 63 between one face 67 of one of the journal blocks 34 and the lever 56'. In this embodiment during normal operation of the alarm clock outside of the alarm-ringing period the end 63' can be wedged between the lever 56 and the flange 67' of the block 34 to prevent displacement of the lever 56 into between the

contacts

37 and 38. This arrangement is extremely flat and easy to manufacture, while providing all the advantages of the first-described embodiment.

It is to be noted that the alarm clock according to the present invention resets itself automatically. If left alone it will sound automatically every 12 hours for a specified period of time, then shut itself off automatically. Even when shut off by actuation of the lever 42, when the wheel 7 moves back and pulls the

contacts

37 and 38 apart, the end 59 ofthe lever 56 is freed so that this latter can return to its normal position under the influence of the spring 57, and the clock is set to alarm again when the wheel 7 drops into the wheel 11. The

teeth

16 and 19 are all at different radial spacings outwardly from the center of the wheel 7 so that they can engage in the corresponding holes only once every l2 hours.

The block 33, as shown in FIGS. la and 5ac is provided with a stop 67 which serves as an abutment for the lever 56 to prevent it from passing completely through between the

contacts

37 and 38. (In FIG. 2 the lever 56 is stopped by the surface 67 in the same manner.) Screws 66 hold the body 33 to the plate 8 and formations 69 fit into the plate 8 to center it surely.

In an advantageous embodiment of the clock according to the present invention, another switch 105 or pair of contacts is provided in series with the two pairs described above which is periodically interrupted to provide an on-off acoustical or visual signal that is generally considered to be more desirable, and which saves electrical energy. This additional switch is advantageously coupled to the relatively fast-moving movement 113 of the clock. Advantageously a metallic cylinder 106 is mounted on the rapidly rotating shaft of this movement. This cylinder is provided with a pair of

circumferential ridges

107, 108 of which at least one has an insulated sector. A small

conductive wiper

110, 111 is mounted to contact each one of these ridges. These two wipers are mounted on an insulating block 112 and are wired, preferably, in series with the other two pairs of contacts. As the cylinder turns the two wipers contact the metallic cylinder and form a closed circuit; however, as soon as one or the other rides up on the insulated sector ofthe ridge so provided, the connection is broken. Several such sectors can be provided, on one or both ridges to interrupt the circuit more often.

In an advantageous embodiment, these wipers are connected to printed circuitry serving to connect up all the various electrical devices in the clock. To this end, it is advantageous ifthe dry cell battery 100 used in the clock has one pole merely grounded to the

plates

1, 8, etc. and the other pole connected to one side of the electrical movement, to one side of the dial lamp, 109 and through another switch 101 to the three pairs of in-series contacts. This last-mentioned switch should be a simple SPST switch which can hold in the open or closed position and which can be actuated by the user to cut off the alarm for any desired length of time, from 12 hours to several months. Thus, if the user does not need an alarm clock, but only a clock for telling the time, he can override and eliminate the alarm function by opening the switch.

The buzzer or bell 102 of the alarm is advantageously mounted on the back plate 1 of the clock and contacts the hot" nongrounded terminal of the battery through a deformable springlike member 103. In this case the alarm on-off switch described immediately above need merely be another nonconducting, advantageously synthetic-resin body 104 which can be actuated by the user to come between the member and the terminal of the battery to disconnect the latter from each other. Displacement of this insulating body out from between the member and the battery pole or the element connected thereto will let the member drop back into contact from its own inherent resilience.

What is claimed is:

1. In an alarm clock having'a dial, an electrical alarm, an electric clock drive cooperating with said dial, electrical dialillumlnating means, and an alarm circuit connected with said electrical alarm and including a first switch triggerable by said drive at a preset time to energize said alarm, the improvement which comprises a member actuatable for opening said switch to deenergize the alarm and to limit the duration of the alarm signal and automatically resettable thereafter; means responsive to the actuation of said member for operating the dial-illumination means; and a lever mechanism coupled with said drive and effective upon actuation of said member for the illumination of the dial simultaneously with closure of said switch at said preset time for effectuating electrical energization of said alarm and requiring release of said member and reactuation thereof to deenergize said alarm.

2. The improvement defined in claim 1 wherein said electric clock drive comprises an axially shiftable hour-wheel and said alarm circuit comprises a first pair of contacts controlled by rotation of said hour-wheel and a second pair of contacts in series with said first pair of contacts and closable upon axial shifting of said hour-wheel, said lever mechanism being operatively connected with said hour-wheel, said member and said contacts for automatically opening the first pair of contacts upon rotation of the hour-wheel past said preset time and for opening said second contacts by axial displacement of said hour-wheel, said mechanism including an alarm-set wheel receiving said hour-wheel, and a contact-breaking lever receivable between the contacts of said second pair retained in a contact-opening position upon movement of said hourwheel axially into said alarm-set wheel but withdrawn from between said contacts of said second pair into a normal position upon axial lifting of said hour-wheel out of said alarm-set wheel.

3. The improvement defined in claim 2 wherein said hourwheel and said alarm-set wheel are provided with cooperating formations permitting engagement of said hour-wheel in said alarm-set wheel in two steps including a first step forming a connection between said hour-wheel and said alarm-set wheel during rotation of said hour-wheel through an arc corresponding to a predetermined automatic duration of said alarm signal, and a second step commencing at the conclusion of said rotation of said hour-wheel corresponding to said duration wherein said hour-wheel open-circuits said alarm.

4. The improvement defined in claim 3 wherein said hourwheel is composed of synthetic resin and confronts said alarmset wheel along one side of said hour-wheel, said formations including teethlike dogs on said hour-wheel along the side thereof confronting said alarm-set wheel and angularly offset from one another about the axis of rotation of said hourwheel, each of said dogs having one steep flank, said formations further including an array of recesses formed in said alarm-set wheel at angular locations corresponding to those of said dogs for receiving same and enabling axial shifting of said hour-wheel upon rotation thereof relative to said alarm-set wheel, said hour-wheel being provided with an annular contact plate and said alarm-set wheel having a complementary electrical contact surface engaging said plate, said annular contact plate being provided with a contact tongue on the side thereof along which said dogs are disposed and having an end projecting beyond the steep flank of one of said dogs through a distance equal to said alarm-duration rotation arc and constructed and arranged so that said tongue is out of contact with said alarm-set wheel when said hour-wheel is lifted therefrom and so that said tongue contacts said alarm-set wheel on engagement of said hour-wheel into said alarm-set wheel whereby the latter contact has a duration equal to the predetermined duration of said alarm signal.

5. The improvement defined in claim 4 wherein three such dogs are provided on said hour-wheel with angular equispacing of and said tongue is disposed proximally to one of said dogs, said one of said dogs being located at a greater radial distance from the axis of said hour-wheel than the others of said dogs.

6. The improvement defined in claim 4 wherein said contact plate is a metal ring mounted along the side of said hour-wheel provided with said dogs and said tongue is formed unitarily on said rings.

7. The improvement defined in claim 4 wherein said contact plate is laminated on said hour-wheel and said tongue is a conductive piece secured to said plate.

8. The improvement defined in claim 2 wherein said drive is provided with a front plate, said mechanism further comprising a switch spring rockably mounted on said plate and electrically insulated therefrom but parallel to said plate and operatively connected to said hour-wheel and in conductive relationship therewith for rotation of said spring upon axial shifting of said hour-wheel, an abutment contact engageable by said spring upon rotation thereof, a contact-breaking lever rotatable against a restoring force to intervene between said spring and said abutment contact, and a control lever springbiased into a normal position and actuatable to displace said contact-breaking lever, said contact-breaking lever being locked in a position between said spring and said abutment contact until it is released by said spring upon lifting of said hour-wheel, said spring and said abutment contact forming said second pair of contacts.

9. The improvement defined in claim 8 wherein said dial-illuminating means comprises a third pair of contacts closed upon actuation of said member.

10. The improvement defined in claim 8 wherein said switch-spring has an end linked with said hour-wheel and formed with three tongues including a middle tongue gripping one side and a pair of end tongues gripping the opposite side of said hour-wheel, said hour-wheel being formed with an annular contact plate in sliding engagement with at least one of said tongues.

11. The improvement defined in claim 8 wherein said contact-breaking lever is elongated and formed from a synthetic resin with a flattened front end provided with a ridge and a groove, said contact-breaking lever being provided unitarily with a thin synthetic-resin extension, said lever mechanism further comprising a pin retaining said extension under prestress.

12. The improvement defined in claim 8, further comprising a synthetic-resin body mounted on said front plate and carrying said switch spring and said abutment contact, said lever mechanism further comprising a mounting movably supporting said contact-breaking lever on said body and a pin mounted on said body and limiting the displacement of said contact-breaking lever.

13. The improvement defined in claim 2 which comprises a further pair of contacts impulsively actuated by a quickly running part of said drive for rhythmically interrupting said alarm signal.

14. The improvement defined in claim 13 further comprising a metallic cylinder rotated by said quickly running part of said drive and provided with a pair of ridges, at least one of said ridges being formed with an insulated sector, said further pair of contacts respectively engaging said ridges.

15. The improvement defined in claim 8 further comprising a spring element resiliently bearing upon said hour-wheel and urging same axially in the direction of said alarm-set wheel, said spring element having an extension reaching into the path of said contact-breaking lever for preventing the movement of said contact-breaking lever by the contacts of said second pair when said hour-wheel is not received in said alarm-set wheel when said member is actuated for dial illumination.

16. The improvement'defined in claim 15 further comprising an actuating spring acting upon said member for retaining said spring element in engagement with said contact-breaking lever, said contact-breaking lever being formed with a slit receiving a projection of said spring element, said slit and the forces of said spring element and said actuating spring being so dimensioned with respect to the sliding friction in said lever mechanism that upon lifting of said hour-wheel said contactbreaking lever is released by said spring element only upon return of said member in the direction of its unactuated position.

17. The improvement defined in claim 8 further comprising a spring element bearing axially upon said hour-wheel in the direction of said alarm-set whee and having an extension reaching into the region of said contact-breaking lever, said extension having a free end engageable with said contactbreaking lever for preventing movement thereof between the contacts of said second pair when said hour-wheel is axially lifted out of said alarm-set wheel and said member is actuated to illuminate the dial.

18. The improvement defined in claim 17 wherein said mechanism is so constructed and arranged that said end retains said contact-breaking lever out from between said contacts of said second pair until said member has returned toward its normal position sufficiently to prevent entry of said contact-breaking lever between the contacts of said second pair under the resilient force applied to said contact-breaking lever.

19. The improvement defined in claim 2 wherein the clock has a conductive housing, further comprising an electric current source having one pole connected to said housing, said alarm, said drive and said dial-illumination means, each hav ing one side electrically connected to said housing.

20. The improvement defined in claim 8 wherein one of said dogs constitutes a drop-in tooth receivable in a corresponding recess to permit axial displacement of said hour-wheel into said alarm-set wheel, said tooth being provided with a lateral protrusion supporting said tongue.

21. The improvement defined in claim 11 wherein said tongues of said switch spring are provided with bent-up portions with coupling bumps for effecting a rocking movement of the switch spring upon a rolling movement of the bumps on said hour-wheel.

22. The improvement defined in claim 8 wherein said lever mechanism comprises an elastic element operatively connecting said member with said contact-breaking lever.

23. The improvement defined in claim 22 wherein said contact-breaking lever is formed unitarily from synthetic resin and said elastic element constituting a portion thereof.

24. The improvement defined in claim 8 wherein said switch spring has two flaps provided with bores defining a rocking axis, said mechanism further comprising a pivot pin passing through said bores and a synthetic-resin mount supporting said pin.

25. The improvement defined in claim 2 further comprising a switch in series with said pairs of contacts for deenergizing said alarm while permitting operation of said drive and dial-illuminating means.

26. The improvement defined in claim 23 further comprising a source of electric current, said switch including a contact engageable with said source and an electrically insulated member interposable between said source and said contact engageable therewith.

Claims

1. In an alarm clock having a dial, an electrical alarm, an electric clock drive cooperating with said dial, electrical dialilluminating means, and an alarm circuit connected with said electrical alarm and including a first switch triggerable by said drive at a preset time to energize said alarm, the improvement which comprises a member actuatable for opening said switch to deenergize the alarm and to limit the duration of the alarm signal and automatically resettable thereafter; means responsive to the actuation of said member for operating the dialillumination means; and a lever mechanism coupled with said drive and effective upon actuation of said member for the illumination of the dial simultaneously with closure of said switch at said preset time for effectuating electrical energization of said alarm and requiring release of said member and reactuation thereof to deenergize said alarm.

2. The improvement defined in claim 1 wherein said electric clock drive comprises an axially shiftable hour-wheel and said alarm circuit comprises a first pair of contacts controlled by rotation of said hour-wheel and a second pair of contacts in series with said first pair of contacts and closable upon axial shifting of said hour-wheel, said lever mechanism being operatively connected with said hour-wheel, said member and said contacts for automatically opening the first pair of contacts upon rotation of the hour-wheel past said preset time and for opening said second contacts by axial displacement of said hour-wheel, said mechanism including an alarm-set wheel receiving said hour-wheel, and a contact-breaking lever receivable between the contacts of said second pair retained in a contact-opening position upon movement of said hour-wheel axially into said alarm-set wheel but withdrawn from between said contacts of said second pair into a normal position upon axial lifting of said hour-wheel out of said alarm-set wheel.

3. The improvement defined in claim 2 wherein said hour-wheel and said alarm-set wheel are provided with cooperating formations permitting engagement of said hour-wheel in said alarm-set wheel in two steps including a first step forming a connection between said hour-wheel and said alarm-set wheel during rotation of said hour-wheel through an arc corresponding to a predetermined automatic duration of said alarm signal, and a second step commencing at the conclusion of said rotation of said hour-wheel corresponding to said duration wherein said hour-wheel open-circuits said alarm.

4. The improvement defined in claim 3 wherein said hour-wheel is composed of synthetic resin and confronts said alarm-set wheel along one side of said hour-wheel, said formations including teethlike dogs on said hour-wheel along the side thereof confronting said alarm-set wheel and angularly offset from one another about the axis of rotation of said hour-wheel, each of said dogs having one steep flank, said formations further including an array of recesses formed in said alarm-set wheel at angular locations corresponding to those of said dogs for receiving same and enabling axial shifting of said hour-wheel upon rotation thereof relative to said alarm-set wheel, said hour-wheel being provided with an annular contact plate and said alarm-set wheel having a complementary electrical contact surface engaging said plate, said annular contact plate being provided with a contact tongue on the side thereof along which said dogs are disposed and having an end projecting beyond the steep flank of one of said dogs through a distance equal to said alarm-duration rotation arc and constructed and arranged so that said tongue is out of contact with said alarm-set wheel when said hour-wheel is lifted therefrom and so that said tongue contacts said alarm-set wheel on engagement of said hour-wheel into said alarm-set wheel whereby the latter contact has a duration equal to the predetermined duration of said alarm signal.

5. The improvement defined in claim 4 wherein three such dogs are provided on said hour-wheel with angular equispacing of 120* and said tongue is disposed proximally to one of said dogs, said one of said dogs being located at a greater radial distance from the axis of said hour-wheel than the others of said dogs.

8. The improvement defined in claim 2 wherein said drive is provided with a front plate, said mechanism further comprising a switch spring rockably mounted on said plate and electrically insulated therefrom but parallel to said plate and operatively connected to said hour-wheel and in conductive relationship therewith for rotation of said spring upon axial shifting of said hour-wheel, an abutment contact engageable by said spring upon rotation thereof, a contact-breaking lever rotatable against a restoring force to intervene bEtween said spring and said abutment contact, and a control lever spring-biased into a normal position and actuatable to displace said contact-breaking lever, said contact-breaking lever being locked in a position between said spring and said abutment contact until it is released by said spring upon lifting of said hour-wheel, said spring and said abutment contact forming said second pair of contacts.

16. The improvement defined in claim 15 further comprising an actuating spring acting upon said member for retaining said spring element in engagement with said contact-breaking lever, said contact-breaking lever being formed with a slit receiving a projection of said spring element, said slit and the forces of said spring element and said actuating spring being so dimensioned with respect to the sliding friction in said lever mechanism that upon lifting of said hour-wheel said contact-breaking lever is released by said spring element only upon return of said member in the direction of its unactuated position.

17. The improvement defined in claim 8 further comprising a spring element bearing axially upon said hour-wheel in the direction of said alarm-set wheel and having an extension reaching into the region of said contact-breaking lever, said extension having a free end engageable with said contact-breaking lever for preventing movement thereof between the contacts of said second pair when said hour-wheel is axially lifted out of said alarm-set wheel and said member is actuated to illuminate the dial.

19. The improvement defined in claim 2 wherein the clock has a conductive housing, further comprising an electric current source having one pole connected to said housing, said alarm, said drive and said dial-illumination means, each having one side electrically connected to said housing.