US2757365A - Electric bell, buzzer or similar device - Google Patents

Description

July 31, 1956 c. P. PEREZ ELECTRIC BELL, BUZZER OR SIMILAR DEVICE 2 Sheets-Sheet 1 Filed April 17, 1953 R m m m P De re 2:

July 31, 1956 c. PEREZ 2,757,365

ELECTRIC BELL, BUZZER OR SIMILAR DEVICE Filed April 17, 1953 2 Sheets-Sheet 2 BY 74pm United States Patent Ofi Fice 2,757,365 Patented July 31, 1956 2,757,365 ELECTRIC BELL, BUZZER OR SIMILAR DEVICE Carlos Pablo Perez, Martinez, Argentina Application April 17, 1953, Serial No. 349,461 2 Claims. (Cl. 340-393) The present invention relates to an electric bell, buzzer or similar device and has for its object the provision of an improved device operating directly with alternating current from power mains but producing a harmless voltage at the call buttons.

By the use of the present invention a considerable economy is achieved, since the use of a separate transformer is avoided.

Several devices have already been developed to avoid the use of the transformer previously required for the operation of bells on the power mains. However, none of them achieved the results obtained by the use of the present invention with the same economy. All previous devices required, for equal results, more iron, more copper or more of both materials and some even more workmanship.

The invention, in either of its embodiments, as bell, buzzer or combined bell and buzzer offers the further advantage that the usual sparking at the make and break points, will all its inconveniences, never occurs.

According to this invention, an electric bell or buzzer signal device is provided comprising a closed substantially rectangular magnetic core, a coil (primary winding) on one limb of said core, for connection to alternating current mains, at least one coil (secondary winding) on the limb of said core opposite the primary winding and placed very close to the primary, that is, practically touching it, so as to make the magnetic circuit a bare minimum, and generating (the secondary coil) a low harmless voltage when the primary winding is connected to the mains; an armature, partially surrounding at least one of the coils mentioned and extending from one to the other of the unwound limbs of the core, and a bell or buzzer call circuit having circuit closing buttons (or other circuit closing devices) in circuit with the secondary winding.

In order that the invention may be clearly understood and readily carried into practice, a preferred embodiment thereof has been shown by way of example in the accompanying drawings, in which a combined bell and buzzer in accordance with the present invention is illustrated and in which:

Figure 1 represents the side of the device facing the wall.

Figure 2 is a sectional view taken along the line AA of Figure 1.

Figure 3 represents the other side of the device shown without the bell body 10 and the bridge 11 (Figure 2).

Figure 4 shows only the essential parts of Figure 2.

Figure 5 is a wiring diagram.

Fig. 6 is a diagrammatic side elevation showing the device employed as a relay.

The drawings show a bell which, in addition to the advantages already mentioned, possesses that of being able to operate either as a bell or as a buzzer.

As represented in Figs. 15, the electric sound signalling device according to the present invention comprises a closed magnetic core 1, made of magnetic laminations, and two windings 2 and 3, wound on it, of which the primary 2 is connected at one end by a conductor 4 and at the other by a conductor 5 to the supply terminals of the power mains. The two coils 2 and 3 are very near to each other, making in this way the magnetic circuit an absolute minimum. These two coils 2 and 3 have numbers of turns such that when coil 2 is connected to the supply lines, a low harmless voltage is generated on coil 3. The ends of this secondary winding 3 are connected, by means of leads 23 and 24, to the call buttons 25.

A ferromagnetic armature 6 is elastically fixed to one of the remaining unwound limbs of the core by means of screw 8 and its own resilient part 9. This armature forms a magnetic leakage path extending from said one of the unwound limbs into proximity with the other, with the coil 2 at one side of this leakage path and the coil 3 at the other side thereof. Thus flux generated by the coil 2, depending on whether the circuit of coil 3 is open or closed, passes almost entirely through the core portion surrounded by coil 3, or in substantial part through the leakage path via armature 6. In the especially compact arrangement shown, the armature is offset as shown in Fig. 4 to bridge over or surround one or both of the coils 2 and 3 partially, making it possible to place these windings very near to each other. The free end 7 of this armature 6 is shaped in the form of a hammer to strike the bell body 10.

A nonmagnetic bridge 11, fixed to the other side of the unwound limbs of the core 1 by means of screws 8 and 17, supports the bell body 10 by means of screw 12 and spring 13, so that the bell body may be fixed in any desired position. A spring 15 and screw 16 make it possible to adjust the position of the armautre 6.

The whole embodiment is fixed to the box 18 by means of the aforesaid screws 8 and 17. Springs 19 make this mounting elastic and keep the nuts tightened.

Around the small magnetic core 14, fixed to the box 18 by means of screw 27, is Wound the coil 20, connected to conductors 22 and 24. A resilient ferromagnetic armature 21 closes the magnetic circuit.

Conductors 23 and 24 are branched to the bell call buttons 25. The buzzer call buttons 26 are connected to leads 22 and 23.

When no button is depressed the transformer runs on no load and, as is well known, the largest part of the primary flux closes itself through the secondary coil 3, the leakage flux being negligible.

When one of the buttons is depressed, the secondary circuit is closed and an alternating current passes through coil 3, the primary current therefore increasing. The primary and secondary fluxes are, in accordance with Lenz law, constantly opposing each other. The leakage flux is therefore considerably increased, and, as the largest part of it traverses the armature 6, this armature is strongly magnetized alternatively and vibrates at a frequency determined by the frequency of the current.

The hammer 7, therefore, will strike the bell body 10 and the device will operate as a bell.

If one of the buttons 26 is depressed, the secondary circuit is closed through coil 20, of large impedance compared to that of coil 3. The auxiliary magnetic core 14 is then magnetized alternatively and the armature 21 is therefore forced to vibrate. The device will operate as a buzzer. As the current traversing coil 3 is small, the leakage flux will be weak and the armature 6 will not be magnetized enough to vibrate, remaining therefore at rest.

It is obvious that if it is desired to construct a device which will function exclusively as bell, or buzzer, the coil 20, its core and armature 21, as well as call buttons 26, will have to be eliminated. Also, in the case of a device for operation only as a buzzer, the bell body 10 and hammer 7 will be unnecessary. Springs 13, 15 and 3 19 can also be omitted in either case, even in the combined bell buzzer, which will make the embodiment rigid and the regulation thereof somewhat more difficult.

As a relay mechanism the device is applicable in all cases in which alternating power current is available and it is desired that the voltage at the control point shall be low. An exemplary arrangement of such application of the invention is indicated in Fig. 6 in which the elements bearing numbers corresponding to those in Figs. 1-5 are the same, but in which the armature 7 carries a contact 27 that is moved against contacts 28 and 29, which are resiliently mounted (as indicated by springs 30) to follow the vibratory movement of the armature 6-7 relatively close to the core 1, when the secondary circuit 3 (see Fig. 5) is closed; but which do not rise far enough to follow the armature 6-7 when it moves to the more remote position it occupies when the circuit of secondary 3 is open.

The operation of the device when used as just indicated will be readily understood and requires no further explanation for those skilled in the art.

Obviously a number of constructional and detail modifications may be made in the device without departing from the nature and scope of the present invention, as defined in the appended claims.

Having now particularly ascertained and described the nature of the present invention and the manner in which the same is to be performed, what I claim is:

1. A signal device comprising a closed substantially rectangular magnetic core, a primary winding on one leg of said core for connection to alternating current mains, at least one low voltage secondary winding on the leg of said core opposite said primary winding and placed very close to said primary winding, a movable armature having end portions lying proximate to the third and fourth legs of said rectangular core and having an outwardly displaced central portion surrounding a part of at least one of said windings, and contact means for closing the circuit of said secondary winding, said armature vibrating in a plane normal to the plane of said core, and without contacting said partially surrounded winding when the circuit of said secondary winding is closed.

2. A signal device according to claim 1 further comprising a coil wound on an auxiliary core, the said coil having a large impedance compared to that of said secondary Winding, a resilient vibratable armature comprising part of the magnetic circuit of said auxiliary core, and a circuit, including said coil and means for closing the circuit thereof, connected in series with said secondary winding.

References Cited in the file of this patent UNITED STATES PATENTS 1,048,913 Stuart Dec. 31, 1912 1,622,862 Detmers Mar. 29, 1927 1,979,127 Warrick Oct. 30, 1934 2,002,433 Cowles -a May 21, 1935 FOREIGN PATENTS 464,149 Great Britain Apr. 13, 1937

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