US3339034A

US3339034A - Electric alarm release and timing device

Info

Publication number: US3339034A
Application number: US500076A
Authority: US
Inventors: Deladerriere Andre
Original assignee: Individual
Current assignee: Individual
Priority date: 1965-02-24
Filing date: 1965-10-21
Publication date: 1967-08-29
Anticipated expiration: 1984-08-29
Also published as: FR1434330A

Description

Aug. 29, 1967 A. DELADERRIERE 3,339,934

ELECTRIC ALARM RELEASE AND TIMING DEVICE Filed Oct. 21, 1965 2 Sheets Sheet 1 United States Patent 3 Claims. 201. 200-38 The present invention relates to an alarm release and timing device for electric time appliances.

In time appliances using an electric dry-cell as energy source, the alarm system actuated by an electromechanical mechanism is generally constituted by a means consuming much energy.

In view of this large energy consumption, it therefore seems valuable to be able to limit the alarm functioning time and it may be considered that in practice the functioning of the alarm during one minute is quite sufficient.

Moreover, the addition of an ancillary mechanism such as an alarm release, very often introduces into the appliance an element which disturbs the setting system.

One aim of the present invention is to obviate this disadvantage while satisfying the abovementioned condition.

Another aim of the invention, which does not attempt to obviate classic basic faults, is to create an assembly of very small dimensions, which is of great interest for the development of the future small electric alarm clock.

The invention therefore has as its objects an electrical alarm release and timing device which guarantees a minimum consumption of energy which provides great functional dependability due to forceful and quick-acting friction contacts which practically eliminates the effects of the release disturbance on the setting means, and which allows said device to have extremely small dimensions.

The device according to the invention comprises, on the one hand, a leaf spring secured to the hour wheel of the movement of the alarm clock and cut to form two helicoidal contact strips and, on the other hand, a release assembly freely rotating about the spindle of said hour wheel and comprising: an index wheel, controlled from outside the appliance and driving the assembly in rotation in the opposite direction to that of the hour wheel, said index wheel being in permanent contact with a false-plate which is earthed; an intermediate annular part made of insulating material and an upper annular metal part with which an alarm stop lever may enter into contact, said lever being maneuverable from outside the appliance and communicating with the alarm which is connected to one pole of an electric dry-cell, the other pole of which is connected to the earth; said upper part being provided with an inside radial projection placed on the trajectory of one of the contact strips of said leaf spring while the other strip of the latter may enter into contact with a helicoidal projection provided in the index wheel, the contact of the first strip with the radial projection of the upper annular part being delayed, in relation to the contact between the second strip and the projection of the index wheel, by a ramp provided in the insulating intermediate annular part and overlapping said radial projection in order to limit the contact according to an annular distance determined by the relative adjustment of the three parts constituting the abovementioned release assembly.

The ramp provided in the intermediate annular part made of insulating material causes the first strip to drop suddenly onto the projection of the upper annular part, thus creating a forceful contact between the two elements, this contact being followed, after sliding of the strip on said projection, by a second dropping of the strip beyond the latter, which causes a sudden breaking of the contact.

The angular distance created between the upper annular part and the ramp of the intermediate insulating part governs the overlap of the projection of said upper annular part and determines the period of functioning of the alarm.

The index wheel is provided with an annular rib sliding on a false-plate connected to the earth of the alarm clock and thus ensuring constant communication between said earth and the projection of the index wheel. An embodiment of said device is described below, by way of simple non-limitative example, with reference to the accompanying drawings, in which:

FIGURE 1 illustrates the elements constituting'the device seen in elevation;

FIGURE 2 illustrates the device seen from above;

FIGURES 3 and 4 illustrate the device in two functional positions.

The device itself is constituted by a leaf spring *1 cut to form two strips 1a and 1b and to fit the hour wheel 2 of the movement of the alarm clock, which effects one complete rotation in twelve hours in the direction of the arrow 7 in FIGURE 2. The spring 1 is firmly secured to said wheel and therefore effects an identical rotation.

The spindle 3 of the wheel 2 pivots in the body (not illustrated) and the base plate 4 of the alarm clock.

There may rotate freely about the spindle 3 an index wheel 5 bearing the pointer which indicates on the dial the time of the alarm release. Said wheel 5 can only move in the direction indicated by the arrow f in FIGURE 2; it is controlled from outside the appliance through the medium of a pinion 6 which meshes with external toothing on the wheel 5. The latter has a helicoidal 5a situated on the trajectory of the strip 1b of the spring 1.

On the index wheel 5 is fixed an annular part 7 made of insulating material, bearing in its turn an annular metal part 8 constituting the supply crown and including a projection 8a adapted to enter into contact with the strip 1a of the spring 1.

The end of a lever 9 may be brought into contact with with said crown 8, said lever pivoting with a spindle 10 passing through an insulating part 11 fixed to the base plate 4. The lever 9 is maneuverable by means of a handle 12 situated outside the appliance and constitutes the alarm stop of the latter.

The spindle 10 is maintained in constant pressure contact with a strip 13 connected by a wire 14 to an alarm 15 connected in turn to the positive pole of a dry-cell 16 by a wire 17. The negative pole is connected to the earth of the appliance by a wire 18. The strip 13 therefore allows the spindle 10 of the lever 9 to pivot while ensuring an excellent frictional contact. The index wheel 5 is provided with an annular rib 5b which rests on a false-plate 19 provided with pillars 20 receiving screws 21 which fix it to the base plate 4. It is seen that the wheel 5 thus, by its rib 5b, ensures an earth return by constant friction on the false-plate 19.

The insulating part 7 is provided with a ramp 7a adapted to overlap the projection 8a of the supply crown 8.

The functioning of the device will be better understood on examination of FIGURES 3 and 4.

FIGURE 3 illustrates the device some moments before the release of the alarm, that is at 21600 (a radians) seconds 21600 (B radians) seconds This angle is accurately'determined during the fitting of the part 8 to the part 7.

It is seen that the passage of the current is therefore established during the alarm functioning time, from the positive pole of the dry-cell 16, through the wire 17, the alarm 15, the wire 14, the strip 13, the spindle 10, the lever 9, the part 8 and its projection 8a, the strip 1a, the strip 1b, the projection 5a of the index wheel 5, the rib 5b of the latter and the false-plate 19 which is earthed.

During this time, the contacts are essentially frictional and guarantee self-cleaning of the contactsurfaces, always a primordial condition of proper functioning, whatever the nature of the contacts.

It is to be noted that between the two positions illustrated in FIGURES 3 and 4, the larger release strip 1a drops from the upper face of the ramp 7a to that of the projection 8a.

The developed length of said strip 1a and the dropping height are such that the pressure variations are very small despite the variations in friction which may exist between the strip 1a and the ramp 7a as well as between said strip and the projection 8a. Moreover, it should be noted that the projection 5a of the wheel 5 has a slight helicoidal curve and thus performs two main functions:

(a) It ensures automatic compensation of the play of the drive gearing of the hour wheel 2 during the alarm release: in other Words, it avoids any partial reduction of the angle 5 at the moment of the drop in terms of time and in a random manner;

(b) It maintains during the alarm functioning time a sufficient earth return contact pressure and the self-cleaning of the earth return contact.

Moreover, this pressure rises slightly during the alarm functioning time and as its opposing torque increases, compensates to some extent the decreasing opposingtorque exerted on the large strip 1a at the time of the first drop which releases the alarm.

When the spring 1 has passed through the angle 5, the second drop stops the alarm and there remains the angle 'y to be passed through by the second strip 1b, which constitutes the safety angle.

It should be noted that this release principle aims at the creation of an extremely fiat assembly.

What I claim is:

1. In an alarm release device for electric time appliances, the improvement comprising: a driven hour wheel rotatably mounted on a spindle, a bifurcated leaf spring having two helicoidal strips secured to said hour wheel, a release assembly freely rotatable about said spindle and comprising an index wheel provided with means for driving said assembly in the opposite direction to that of the hour wheel, said index wheel having a lower part in permanent contact with a grounded false-plate and an upper annular metal part insulated from ground by an intermediate annular part made of insulating material, an alarm stop lever movable into contact with said upper part for connecting said alarm to a power source, said upper part being provided with an inside radial projection placed on the trajectory of one of the contact strips of said leaf spring while the other strip of the latter contacts a helicoidal projection provided on the lower part of the index wheel, the contact of the first strip with the radial projection of the upper annular part being delayed in relation to the contact between the second strip and the projection of the index wheel by a ramp provided in the insulated intermediate annular part and overlapping with said radial projection in order to limit the contact according to an angular distance determined by the relative adjustment of the three parts constituting the above mentioned release assembly.

2. A device according to claim 1 wherein said ramp of the intermediate insulating part is shaped and disposed to cause the sudden dropping of the first contact strip onto the projection of the upper annular part, thus ensuring a forceful contact between the two elements, said contact being followed, after sliding of the strip on said projection by a second dropping of the strip beyond the latter, which results in a sudden opening of the contact and wherein the overlap of the projection of said upper annular part with the ramp determines the period of functioning of the alarm.

3. A device according to claim 1 wherein the index wheel is provided with an annular rib sliding on said false-plate connected to ground of the alarm.

References Cited UNITED STATES PATENTS 2/1890 Straight 340309.1 7/1966 Neif 200-166