US2182452A - Electromagnetic relay - Google Patents

Description

Dec. 5, 1939. w. R. ROSE ELECTROMAGNETIC RELAY Filed Jan. 2, 1957 Patented Dec. 5, 1939 UNITED STATES PATENT OFFiCE ELECTROMAGNETIC RELAY William Robert Rose, Coventry, England, assignor to The General Electric Company Limited,

London, England 7 Claims.

The present invention relates to electromagnetic relays, and has for its object the provision of a two-position relay having improved operating characteristics, whilst at the same time emplglying as many standard or known parts as pos- In telephone systems it is known to employ a relay having an L-shaped yoke, and an armature pivoting on a knife edge on the said yoke and acted upon by an operating coil carried by the yoke, the armature being adapted to move contact springs arranged in piles which are mounted on the same yoke. This type of relay is arranged to remain normally in an unoperated position, the armature and contact springs moving to an operated position and remaining so, only so long as current is applied to the operating coil.

It is also known to construct a relay which remains in either of two positions after a momentary energisation of an operating coil, having an armature pivoted about an axis passing between the ends of the operating coils of the relay, the said armature being locked in either of its extreme positions by means of a spring. This type of relay, however, suffers from the disadvantages that a number of special parts are required, and that a portion of the magnetic circuit is common to both operating coils, this tending to produce incorrect operation under certain extreme conditions.

According, therefore, to the invention, a relay of the two-position type comprises two entirely separate magnetic circuits, each one composed of an operating coil and core, a yoke and an armature, the said magnetic systems being disposed side by side, the two armatures being so interlinked by a rocking member that operation of one by a current through its associated coil causes positive release of the other, the interlinking mechanism being such that the armature last operated remains in this position until the other armature is operated in turn.

In a preferred form of the invention two relay assemblies of the type used in telephone systems are mounted side by side on a common plate. Their armatures are interlinked by a rocking member extending from one to the other and pivoted about an axis passing at right angles through a line drawn parallel to, and midway between the axes of the operating coils of the relays. This said member carries an arm extending into the space between the two relays, its end co-operating with a flat spring bowed and supported between a V notch at one end and a further fiat spring at the other.

This latter spring is tensioned so as to efiect the curvature of the former spring, the said tension being of suflicient strength toensure that after the operation of one armature and consequent release of the other, the moving parts are maintained in this position until the energisation of the operating coil of the released armature.

Either one or both armatures may operate one or more sets of contact springs, and adjustments are provided whereby the retaining action of the bowed spring is compensated for varying contact spring loads. Further adjustments may be provided to compensate for the effects of manufacturing tolerances on the core lengths, and also to correct any possible eccentricity of the pivot on which the member co-operating with the two armatures is mounted.

Reference should now be made to the accompanying drawing, Figure 1 of which shows a partly dismantled relay, Figure 2 a view of the relay seen from the armature end, and Figure 3 a part sectional view taken along line A-A of Figure 2.

Referring to Figure 1, this shows one of the magnetic circuits employed and the device for holding the armatures of the relay in either one of two positions without energisation of either of the operating coils. The magnetic circuit shown comprises a coil I, wound on a core 3, the latter acting upon an armature l pivoted about a knife edge 2. This knife edge is part of a yoke 5 which is L-shaped, and to which is clamped the operating coil and core. The armature, yoke and core of the operating coil form a magnetic circuit, and the whole is mounted on a base plate I by means of screws.

In known types of relays having a yoke similar to that described, the armature is normally held away from the core 3 by the tension of flat contact-making springs mounted in insulating supports on the yoke. As the relay according to the invention has to hold one of the armatures operated without energisation of either of the operating coils, a centre piece 6 fixed to the base plate I is provided, this centre piece carrying a rocker 9 pivoted about an axis N]. This rocker is provided with a transverse portion one end of which co-operates with one armature while the remaining end engages with another armature forming part of the second coil assembly (not shown), which is exactly similar to that disclosed in the drawing, this second assembly being fixed to the base plate by screws passing through the holes 52. As best seen in Figs. 2 and 3, each end of the rocker 9 carries a bead 32 which bears upon one of the armatures and is locked thereto by means of a Z-shaped bracket ll screwed to the armature. These couplings permit the free rotation of the rocker and both armatures about their respective axes.

The rocker also carries an arm M which extends into the space between the two magnetic circuits. The end of this arm is forked and engages with the middle of a bowed spring 13 which at one end engages with a V groove in the centre member 6 and at the other end with a slot in a pin l! which slides freely in a hole in the centre member 5. Pressure is applied to the pin I1 and hence to the spring 13 by means of a further spring 2!! this latter spring being fixed firmly to the centre member 6 by screws 2|. The tension on this spring 20 is such as to maintain the spring 83 in a bowed state, the arrangements being such that when either armature is attracted sufiiciently strongly by its operating coil to move the spring ii! from one extreme position to the other, the armature rocking member and contact springs are retained in this latter position, even though the energisation of the operating coil is removed. Subsequent energisation of the operating coil moves the assembly back to its previous position.

Relays of the type described may be required to carry either few or many contact making springs. As shown, each armature acts upon two sets of changeover contact springs, but many more than these can be carried by each yoke. This means that the tension acting on each armature vary between wide limits so that in order to maintain the armatures and rockers in either of twopositions independently of the spring load, a widely varying force must be applied to the lower end of the spring l3. An adjustment for this force is provided by applying pressure to the spring 20 by means of a screw 22 having a frustro-conical head, the screw being mounted in and engaging with a thread on the centre piece 6. The slot in the screw head is accessible from the front of the relay even when the latter is mounted and in position on a rack. Rotation of the screw in a clockwise direction applies increased pressure to the spring 2!! and hence through the pin I1 to the spring l3. Rotation in the opposite direction reduces the pressure applied to spring I3.

It will be seen from Fig. 2 that the two operating coils lie with their axes parallel, the armatures operating on knife edges 2 and being ret ained thereon by means of the screws and springloaded washers M as shown in Figs. 1 and 3. The contact springs are supported near their front ends by means of a stepped insulator 25 and are fixed at their rear ends between insulating members 26. The clip 21 mounted on the front of the rocker has a bent over extension 28 which retains a pin in position through the rocker, this pin acting as the axis Ill about which the rocker rotates.

It will be noticed that since the two magnetic circuits of the relay are complete in themselves, the centre member 6 can be and is preferably of a non-magnetic material. This assists inpreventing false operation of the relay caused by interaction of the flux produced by the two coils. some of which may traverse the centre member if it is of magnetic material.

Two further adjustments are provided to take care of inequalities likely to arise during the manufacture of the relay. The first of these enables the axis on which the rocker pivots to be moved in a direction towards or away from the fixing plate of the relay. This facility is afforded by means of the U-shaped member 30, which is fixed to the centre piece 6 by the two screws 2|. This member has two slotted holes, one in each end, through which the screws pass. When the screws are loosened the member can be moved in a direction parallel to the centre line of the centre piece 6, carrying with it the pin on which the rocker rotates, and hence the rocker. This enables compensation to be effected for varying core lengths and also for varying travels required on the armatures.

Another adjustment is provided in the fixing of the forked arm M to the rocker. This arm is fixed by means of two screws 3!, both of these screws passing through holes which are extended slightly sideways. When the arm is fixed centrally on the rocker, all adjustments are correct for an equal number of spring sets, and an exactly equal length of cores. Should one of the cores be slightly longer than the other the mean position of the rocker is displaced slightly from a true position at right angles to the plane of the centre piece, this displacing the arm [4 in the gap between the two magnetic assemblies. In order to replace the arm on the exact centre line, the two screws are loosened and the arm moved to one side or the other depending upon which direction the inaccuracy is to be corrected. Tight ening the two screws now enables the arm to function properly.

This adjustment also provides means for correcting the eccentricity of the pin in which. the rocker pivots. Correction is performed in a manner similar to that described for inequality of core length. In addition, this adjustment enables the tension provided on the arm by the bowed spring to be adjusted unevenly on each side, this providing correction for unequal numbers of contact springs operated by the two armatures. Thus if one armature carries one set of contact springs and the other armature two sets, the relay is first adjusted so that the rocker is at right angles to, and the arm on, the centre plane of the relay, then the arm is moved sideways by loosening the two screws 3! until the pressure of the bowed spring on the armature compensates for the unequal load. By this means it is possible for the same current applied to each operating coil in turn to move the relay from one side to the other, the bowed spring retaining the armature in either of its two extremes. independently of the unequal load.

I claim:

1. An interlinking device adapted for mounting on the common base midway between two similar relays to maintain the armatures thereof in opposite positions, said device comprising a center supporting structure, an integral member associated with the armatures. of the relays and arranged to rock on an axis of the center structure midway between said relays, a pin, flat springs, and an arm with one end rigidly attached to said integral member and the other end terminating in a fork engaging the middle of one of said springs supported in a bowed position between a V notch in said center structure and a slotted end of said pin which is free to move and extends through a hole in said structure, and said pin conveying pressure of another flat spring to maintain the bow in the first named spring.

2. An electromagnetic structure comprising two similar relays mounted side by side, a common interlinking device mounted between them, said interlinking device comprising a rocking member pivotally associated with the armatures of said relays for holding the operated relay op erated after said relay is deenergized and until the associated relay is energized and preventing operation of the associated relay while the operated relay is energized, an arm, as a unitary part of said rocking member, extending into the space between the relays and terminating in a forked end, a flat spring in contact at its midpoint with the forked end of said arm, and variable means for causing said spring to bow to either side of its center line.

3. An electromagnetic structure comprising two similar relays mounted side by side on a common plate, an interlinking device with supporting structure mounted between the relays on said plate, said device comprising an integral member interlinking the armatures and rocking on an axis passing midway between the armatures and parallel to said mounting plate, an arm rigidly attached to said integral member terminating in a forked end extending into the space between the relays, a flat spring supported in a bowed position and in association at its midpoint with the forked end of said arm, thus insuring one armature remaining in an operated position and the other in a normal position, another flat spring bearing against said first spring to maintain said bowed position, and means for varying the tension of the latter to effect the tension of the first named spring.

4. In combination with two similar relays mounted side by side but having unequal spring loads an interlinking device supported between the relays insuring that either one remains operated while the other is at normal, said interlinking device comprising a rocking member having a relative association with each armature and rocking on an axis midway between the armatures and parallel to the mounting plate, an arm, adjustably attached to said rocking member, terminating in a forked end extending into the space between the relays, a flat spring supported in a bowed position and associated at its midpoint with the forked end of said arm, means for varying the amount of bowing of said spring and means for varying the association of said arm with said rocking member to compensate for differences in the armature spring loads.

5. An electromagnetic relay comprising two separate relays disposed side by side each having an operating coil and a core, a yoke and an armature, an interlinking mechanism for holding the armatures in either one of two positions without energization, an integral member therein pivotally mounted on an axis perpendicular to a plane containing the axis of the armature and passing midway between the armatures so that operation of one armature by a current through its operating coil causes the positive release of the other armature, the interlinking mechanism between the two armatures being such that the armature last operated remains in this position until the other armature is operated in turn.

6. A relay comprising two separate electromagnetic systems disposed side by side each having an operating coil and a core, a yoke and an armature, a device for holding said armatures in either one of two positions without energization of their operating coils, an interlinking rocker therein extending from one armature to the other armature and pivoted about an axis at right angles to a plane passing through the axis of the armatures and midway between the axis of the operating coils, flat springs, one spring bowed between a V notch at one end and another of said springs at the other end, an arm carried by said rocker extending between the relays and interacting with said one spring toretain said armature in the position to which they are last operated.

7. An electromagnetic arrangement, comprising two relays disposed side by side each having an operating coil and core, a yoke and an armature, an interlinking member for holding the armatures of said relays in either one of two alternate positions without energization, said member extending from one armature to the other armature and pivoted about an axis passing midway between the armatures at right angles to a plane including the axis of said armatures, fiat springs combined so that a first spring rigidly fixed at one end may bear on a second spring so that said second spring is maintained in a bowed position between said relays, and an arm extending from said member to the bowed portion of said second spring for retaining said armatures in one of said positions.

WILLIAM ROBERT ROSE.

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