US2929001A

US2929001A - Armature retaining assembly for an electromagnetic relay

Info

Publication number: US2929001A
Application number: US665394A
Authority: US
Inventors: Bert A Wallace; Earl Van Wie
Original assignee: Deutsche ITT Industries GmbH
Current assignee: TDK Micronas GmbH; International Telephone and Telegraph Corp
Priority date: 1954-06-18
Filing date: 1957-06-13
Publication date: 1960-03-15
Anticipated expiration: 1977-03-15

Description

March 15, 1960 a. A. WALLACE ETAL 2,929,001

ARMATURE RETAINING ASSEMBLY FOR AN ELECTROMAGNETIC RELAY Filed June 13, 1957 FIG. I

United States Patent ARMATURE RETAINING ASSEMBLY FOR AN ELECTROMAGNETIC RELAY Bert A. Wallace, Chicago, BL, and Earl Van Wie, Las Vegas, Nev., asignors to International Telephone and Telegraph Corporation, New York, N.Y., a corporation of Maryland Application June 13, 1957, Serial No. 665,394

2 Claims. (Cl. 317-176) This invention relates to an armature retaining assembly for an electromagnetic relay, particularly of the bellcrank type used in telephone switchboards, with the armature fulcrumed on the forward end of the magnetic return plate. Its principal object is to provide a new and improved armature retaining assembly which provides ease of adjustment in aligning the electromagnet armature in its desired operating position and in maintaining the armature in its operating position irrespective of any precise location of the armature retaining assembly.

In the known relay construction of the above type, a generally T-shaped armature retainer is employed. The main portion passes through a slot in the armature and is secured to the magnetic return plate, thus serving to limit movement of the armature along the fulcrum line. Movement of the armature away from the fulcrum line, which may tend to occur when the electromagnet is deenergized, is limited by the head portion of the retainer. Difliculty, however, is often encountered in properly adjusting the retainer and in aligning the head portion with the armature to serve its retaining purpose without mechanical bind.

According to the invention, the foregoing difficulty is avoided by providing a spring member which urges the armature toward the fulcrum line, and which has a sufficiently small spring rate that accurate positioning of the spring member is not required.

In its illustrated form, the retaining spring member is conveniently secured to the usual T-shaped armature retainer which has its head portion located beyond the extremities of the return plate to permit only the spring member to engage the armature to'hold it against its fulcrum line. Friction between the armature and the arms of the spring member is negligible because of the small area of contact and of the small amount of the spring force.

The above-mentioned and other features and objects of this invention and the manner of obtaining them will become more apparent, and the invention will be best understood, by reference to the following description of the invention taken in conjunction with the accompanying drawings comprising Figs. 1 to 4, wherein:

Fig. l is a plan view of a relay embodying the invention;

Fig. 2 is a side elevation view of the relay of Fig. l; Fig. 3 is a front elevation view of the relay of Fig. 1; and

Big. 4 shows the armature-retaining assembly of the relay of Fig. l greatly enlarged.

Referring particularly to Figs. 1 and 2, the relay shown therein includes an electromagnet 10, an armature 11, a twin stack switch assembly 12, both stacks of which are actuable by the electromagnet through the armature, and an L-shaped return plate 13 on which the switch assembly and armature are mounted.

The electromagnet includes a coil 14 and a cylindrical magnetic core 16 extending therethrough. The

2,929,001 Patented Mar. 15, 1960 ICC rear end of core 16 is drilled and tapped to receive screw 17 to secure to coil to the return plate 13.

The electromagnet 10 has a round front spoolhead 18 and a square rear spoolhead 19. The front and rear spoolheads are secured to the core 16, as by press fit.

Coil 14 has rearwardly extending winding terminals 20, located in a row along the lower edge of the rear spoolhead 19.

As shown most clearly in enlarged Fig. 4, the armature is held in position at the front of return plate 13 by an armature-retaining assembly comprising a retainer member 23 and a spring member 78.

The retainer member 23 is generally of T-shaped structure having a flat bifurcated shank portion 28 and crossarms 24 disposed at right angles with portion 28. To enable the retainer member 23 and armature to be mounted on the return plate, an aperture or cut-out portion is provided in the arm 26 of armature 11 through which the flat bifurcated extending portion 28 of the retainer may be fastened to the return plate 13. The bifurcated extension portion comprises a pair of arms 29 defining a slot within which a fastening screw 30 is snugly accommodated for threaded engagement with a hole in the top of the return plate 13. In this manner, the arms 29 can be either tightened against the return plate or slidably disengaged from the return plate upon loosening the screw 30. Member 23 abuts the sides of the aper ture of armature 11 to prevent any side movement thereof.

Spring member 78, made from spring-tempered wire, is formed to be secured snugly to the crossarms 24 of armature retainer 23 by a clip-on action. When secured to retainer 23, the straight portion (Fig. 3) of spring member 78 underlies portion 28 of retainer 23 to prevent any rotation of the spring member and the two arms 79 of member 78, looped around respective crossarm portions 24, extend upwardly in a plane making approximately a 30-degree angle with the plane of the retainer 23, the arms being disposed between the crossarms 24 and the bifurcated end of the retainer.

When the retainer 23, with its spring member 78 secured thereto, is mounted on plate 13 by screw 30, the bifurcated portion 28 of retainer 23 is longitudinally positioned by sliding it rearwardly until the spring arms 79 come into contact with armature 11 and are disposed at about equal angles with

parts

26 and 27, which comprise the angularly disposed arms of the bell-crank armature 11. In this position, the arms 79 bear against the bent portion of armature 11 to prevent its upward or forward displacement.

The above arrangement provides ease in adjusting the armature-retaining assembly since the yield of the spring arms 79 permits satisfactory armature 27 operation irrespective of any precise location of the armature retainer 23. on return plate 13.

The twin-stack switch assembly of Figs. 1 and 2 includes a cap-plate 37, base plate 38, and parts clamped between them by screws 40 which pass through openings in the cap-plate and intervening parts to the base plate, wherein they are threadedly received. Two

opposed columns

42 and 43 of the contact sets are included in the same unitary assembly 12. This construction enhances rigidity and reduces the number of assembly and clamping screws required. The switch assembly is readily installed in position on return plate 13 and is simply secured by two mounting screws 41 which pass through assembly 12 for threaded engagement with apertures (not shown) in the upper surface of return plate 13. The switch assembly lies fiat upon the return plate with protruding ends of clamping screws 40 thereof being received in provided clearance openings (not shown) in the return plate.

The traveling blades of both columns are moved by a pair of similar actuating ladders 58, as shown in Figs. 1 and 2, which move the blades into and out of electrical contact with the fixed blades of their respective contact sets in response to movement of the associated armature. The ladder provided for column 42 is actuated simultaneously with the ladder of column 43 by the armature 11. Each of the contact blades of

columns

42 and 43 has a terminal portion 60 for the attachment of circuit wires. The terminals are staggered as shown in Fig. 1 for wiring convenience.

Upon energization of the electromagnet 10, the associated armature 11 turns about its axis to bring its lower portion 27 into contact with the end of the core 16 and to move its upper portion 26 to cause the travelling blades of

columns

42 and 43 to move into contact with their respective stationary blades. During such movement of the armature 11, lines of magnetic flux maintain the armature against the knife-like edge of return plate 13, the arms 79 of spring assembly 78 permitting free movement of the armature about its fulcrum.

Upon deenergization of the electromagnet, the downward tension of the associated traveling blades of the switch assembly serves to return the armature to its normal illustrated position. While returning to its unoperated position as a result of discontinuation of magnetic fiux, the armature has a tendency to move away from the fulcrum line and be out of operating position when the electromagnet is energized again. However, according to the invention arms 79 by spring tension maintain the armature properly in position against the return plate pivot edge.

While we have described above the principles of our invention in connection with specific apparatus, it is to be clearly understood that this description is made only by way of example and not as a limitation to the scope of our invention.

We claim:

1. An electromagnetic device comprising an electromagnet, a magnetic plate secured to the electromagnet, and an armature pivotally supported on an elongated fulcrum on the plate, the armature having an aperture through which the plate is made accessible, means including a rigid retaining member and a spring retaining member for maintaining the armature on the fulcrum in operative relation with the electromagnet for movement about the fulcrum between an operated and an unoperated position, means for securing the rigid retaining member to the plate through the aperture in the armature to limit the movement of the armature along the fulcrum, means for securing the spring retaining member fixed on the rigid retaining member for resilient engagement with the armature to hold the armature against movement away from the fulcrum, and adjustment means for variably tensioning the spring retaining member against the armature to urge it variably against the said fulcrum, said adjustment means being included in the said means for securing the retaining member to the said plate and comprising means for adjustably positioning the retaining member on the said plate.

2. Structure for yieldingly retaining an apertured armature of an electromagnet operatively in position on a fulcrum fixed with the electromagnet, which comprises a T-shaped rigid retaining member having its stem portion extending through the aperture of the armature and removably fixed with the electromagnet structure, with the head portion wider than the aperture in the armature and located along the fulcrum but spaced outwardly therefrom in a position to clear the armature, and a resilient supplemental retaining member attached to the head end of the rigid retaining member to yieldingly hold the armature on its fulcrum, the supplemental retaining member consisting of a single length of spring wire of a generally U-shaped form which provides a pair of armature-engaging arms each extending transversely of the fulcrum line between the armature and the head portion of the rigid member, such arms being joined integrally by a common portion which crosses and contacts the stem portion of the rigid member near the head portion thereof, eachtarrn of the resilient supplemental member including an intermediate portion which extends around a separate arm of the head portion of the rigid retaining member, thereby providing an increased spring-arm length.

References Cited in the file of this patent UNITED STATES PATENTS 2,235,861 Wood Mat. 25, 1941 2,461,360 Vincent Feb. 8, 1949 2,686,850 Earle Aug. 17, 1954