US2421998A - Electrical circuit controlling device - Google Patents

Description

June 10, 1947. CYPSER 2,421,998

ELECTRICAL CIRCUIT CONTROLLING DEVICE Filed May 16 1941 INSULATION J5 J1 l I 10 J 6) /z I I 4- J f? i 12 15 9 I 13 11 i 7 52/10/25 Mum 7 Patented June 10, 1947 ELECTRICAL CIRCUIT. CONTROLLING DEVICE Hugo F. Cypser," New York,"N. Y., assignor to Signal Engineering & Manufacturing Company, New York, N. Y., a-corporation f Massachusetts Application May 16, 1941, Serial No. 393,801

(01. ZOO--98) 3 Claims.

"1 The'present' invention relates to electrical circuit controlling devices or relays, particularly adapted for'use in a telephone extension signal circuitemploying a' relay responsive to telephone ringing current to-actuate an audible or visual signal. When'a relay'of this character is energized'by telephone ringing current, it closes and completes a circuit froma suitable source of power to the extension signal, and in many instances, it is desirable to have the extension signal remain continuously.energized until the person called answers the telephone.

Heretofore, telephone extension relays have been provided-with various types of mechanical latchingdevices; which serve to hold up the relay armature-after the'first application of ringing current, soas to 'maintain the circuit of the extension signal closed. Such mechanicallatching devices are usually'released by a manual operation,so as to deenergize the extension signal whensthe person called answers the telephone. Ithasalso been proposed to provide for the release of mechanical latching devices by electromagnetic means, :operable by telephone talking current which flows when-the receiver is lifted.

Howeven-because of the feeble nature of telephone talking current, and the necessity for limiting the electricalresi'stance of the latch-releasingwindingthe for'ceavailable for releasing a mechanical latch mechanism by talking current is extremely small; and is effective only through avery limited movement. As a consequence, the mechanical 'latch mechanism of such magnetic release relays must be very delicate, with only a small permissible movement of the parts thereof; and past experience has shown that such relays are unreliable inthe presence of external'vibrationor mechanical shock.

According to the present invention, there is provided animproved relay, particularly adapted for the control of telephone extension signals, which relay is entirely free of the objections and difiiculties encountered with previous mechanical latch relaysf'The relay of the present invention is particularly characterized by a hold-in and release'device that operates entirely on a magnetic principle. 50 that it will-be reliably held in position without requiring any delicate adjustments, -or=-being subject to' displacement by external vibrationor shock. Furthermore, the

magnetic hold-inof the present relay is adapted to. be readily released by the feeble current of the telephone talking circuit, Without the necessity of developing any force such as would be required for releasing a mechanical latch.

' The above and other advantageous features of the invention will hereinafter'more fully appear from the following description, considered in connection with the accompanying drawings, in which:

Fig. 1 is a View in. front elevation of av relay embodying/the present invention, with its associated circuit connections shown diagrammatically.

Fig. 2 is a view in side elevation of therelay shown in Fig. 1, in an open circuit condition.

Fig. 3 is a view in side elevation, showing the relay in a closed circuit condition.

1.Fig,' 4 is. a fragmentary sectional view along the line 4- -4 of Fig, 3, looking in the direction of the arrows.

Referring to the drawings, the relaycomprises a U-shaped magnetic core I mounted on an insulating baseZywith one leg of the core I surrounded by an energizing Winding 3. The other core leg carries anarmature 4 pivoted at 5, and the'armature' 4carries contacts 6 extending upwardly in the direction of spaced contacts I mounted on the base 2.

'Ihe'stationary contacts 1 are connected across a' suitable source of electrical energy S in series with a signal f anydesired type, so that bridging' of 'the'contacts 1 by the connected contacts amounted on the armature 4, will cause energization of the signala. The terminals of the winding 3 are adapted to be connected to a source of telephone'ringing current, as by means of a key K, so that animpulse of ringing current will 'cause the armature 4 to pull up from the position of-Fig. 2 into the position of Fig. 3, and thereby'causeenergization of the telephone extension signal 8,-upon bridging of the contacts I.

As previously pointed out, the relay of the present invention contemplates the provision of means for magnetically holding in the relay armature 4 following energization of the relay winding 3 by ringing current, so that the telephone extension signal- 8-Will remain energized until the armature A is magnetically released in response to the flow of telephone talking current 3 when a receiver is lifted. To this end, the armature 4 provides a downwardly extending member 9 of resilient material, the lower end of which carries an auxiliary held-in armature ill of magnetic material.

At best shown in Figs. 2 and 4, the armature I is normally spaced away from the ends of the poles H of a. permanent magnet M, supported from the base 2 by means of a bracket I2. However, when the relay armature 4 is drawn upwardly through energization of the winding 3 by an application of ringing current, the armature II) will be moved into the position of Fig. 3, wherein attraction of the armature II] by the poles II will hold the armature in this position, with resultant fiexure of the member 9, for a purpose which will shortly appear. With the armature I0 so held by the magnet M, deenergization of the winding 3, upon discontinuance of ringing current, will not result in dropping out of the armature 4, and the contacts 6 will remain in engagement with the contacts 1, to maintain the circuit of the extension signal 8.

The poles II of the magnet M are surrounded by release coils I3, and these coils are so wound that the flow of current therethrough will create a demagnetizing effect, tending to reduce the magnetic flux through the armature I0 between the poles II. As indicated in Fig. 1, the coils I3 are adapted to receive telephone talking current when a receiver is lifted, and the flow of this relatively feeble current is suflicient to release the hold-in armature I0, due to the demagnetizing effect of the coils I3, and the releasing force stored in the flexed member 9.

As previously pointed out, the member 9 is fiexed when the armature I0 is held attracted by the poles II, as shown in Fig. 3. This flexure is due to the fact that the armature I0 would not actually engage the poles II, were the armature 4 to be tuned slowly about its pivot 5 to engage the end of the core leg on which the winding 3 is mounted. That is to say, with the armature l0 occupying the dotted line position of Fig. 2, slightly separated from the poles I I, there would be no flexure of the member 9.

However, in the actual operation by the relay, the armature 4 is moved very quickly into contact with the core I, in response to energization of the winding 3 by ringing current. As a result of such rapid movement, the inertia of the holdin armature ID at the free end of the member 9 is quite sufficient to carry the armature I0 past the dotted line position of Fig. 2, into actual engagement with the ends of the poles II. The resulting attraction of the armature ID by the poles II is then sufficient to hold the armature It in the position of Fig. 3, wherein the member 9 is flexed to such a degree that a retractive force is built up and maintained therein as long as the armature I0 is held by the poles II.

With the armature I0 occupying the position of Fig. 3, a relatively feeble current flowing through the demagnetizing coils I3, will reduce the magnetic flux flowing through the armature it and poles II to a value insufficient to overcome the retractive force of the then flexed member 9. Thereupon, the armature ID will release to permit the main armature 4 to fall back by gravity and open the circuit of the telephone extension signal 8 through separation of the relay contacts 6 and I. It has been found that the flow of normal telephone talking current through coils l3, when a receiver is lifted, is quite sufficient to so demagnetize the poles I I as to quickly release the armature I0. In fact, tests have shown that the current consumption of the coils I3 when releasing the armature I0, is only about one-half of the current required by relays employing a magnetically operated trip for a mechanical latch that requires the performance of work by an armature, in order to obtain the tripping movement.

From the foregoing, it is apparent that by the present invention there is provided an improved circuit controlling device, characterized by the provision of a hold-in operating entirely on a magnetic principle, so that it is not subject to displacement by ordinary vibration or shock, and

r is releasable in response to the flow of a feeble current, such as is available in a telephone talking circuit.

I claim:

An electrical circuit controlling device comprising in combination a magnetic core carrying a winding, a stationary contact, a main armature pivotally mounted on said core and carrying a contact movable into engagement with said stationary contact in response to attraction of said armature by said winding, an extension of flexible material carried by said armature and terminating in a secondary armature of magnetic material, a permanent magnet providing poles opposite the ends of said secondary armature, with said secondary armature being held by said magnet with said extension in flexed condition when said main armature moves to close said contacts in response to energization of said winding and means for neutralizing said permanent magnet to release said secondary armature through the retractive force of said flexed armature extension.

2. An electrical circuit controlling device comprising in combination a magnetic core carrying a Winding, a stationary contact, a main armature pivotally mounted on said core and carrying a contact movable into engagement with said stationary contact in response to attraction of said armature by said winding, an extension of flexible material carried by said armature and terminating in a secondary armature of magnetic material, a permanent magnet providing poles opposite the ends of said secondary armature, with said secondary armature being normally separated from said magnet poles by an air gap. which is closed when said main armature moves in response to energization of said winding to bring said contacts into engagement, and with the attraction of said secondary armature by said magnet serving to hold said armature contacts closed, and said extension in flexed condition, following deenergization of said winding and means for neutralizing said permanent magnet to release said secondary armature through the retractive force of said flexed armature extension.

3. An electrical circuit controlling device comprising in combination a magnetic core carrying a winding, a stationary contact, a main armature pivotally mounted on said core and carrying a contact movable into engagement with said stationary contact in response to attraction of said armature by said Winding, an extension of flexible material carried by said armature and terminating in a secondary armature 01' magnetic material, a permanent magnet providing poles opposite the ends of said secondary armature and a second winding for neutralizing said permanent magnet, with said secondary armature being separated from said magnet poles by an air gap of such width that said secondary armature will be attracted and held only when said main armature moves in response to energization of said Winding to close said contacts and with said extension being flexed in the attracted position of said secondary armature to store energy effective to accelerate release of the main arma ture following deenergization of said first Winding and neutralization of said permanent magnet by the energization of said second winding.

HUGO F. CYPSER.

REFERENCES CITED The following references are of record in the file of this patent:

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