US3076073A - Contactor - Google Patents

Description

Jan. `29, 1963 G, R, TQwNsEND 3,076,073

CONTACTOR Filed oct. s, 1960 INVENTOR. GEORGE R. TOWNSEND 3,076,073 CNTACTR George R. Townsend, Roanoke, Va., assigner to General Electric Company, a corporation ci New York Filed st. 3, 196e, der. No. 6th-343 6 Claims. (Ci. Zitti- 87) This invention relates to circuit breakers of a class which are more frequently referred to as contactors. More particularly the invention relates to an improved construction in a contactor having a normally closed contact and a normally open contact. The new construction specifically relates to improvements in preventing the bouncing of contacts in such devices.

ln electrical control circuits devices frequently are used having a movable armature associated with an electrornagnet whereupon energization of the latter brings about movement ot the former to operate electrical contacts associated with the armature. Normally when the device is energized the armature moves in one direction and when the device is no longer energized the armature is returned to its initial position by a spring or other resilient means. Normally the movement of the armature is mechanically restricted so that upon returning to the initial position the energy or inertia of the armature is absorbed by one of the mechanical limiting elements. Where the speed of operation of the armature is relatively high and where the magnitude of the movement of the armature is relatively large, frequently the inertia of the armature produces erratic operation as a result of encountering the limiting element. Consequently in a device of this nature where the armature carries contacts which normally become closed when the device is deenergzed, the electrical circuit or circuits formed by these normally closed contacts sometimes become interrupted resulting in electrical failures. various means have been used for correcting this condition, and in the present in- Vention a novel concept is employed that results in simple and eicient operation with relatively low cost of manufacture.

it is an object of this invention, therefore, to provide an improved armature construction in a contacter that is operated electromavnetically and which is returned to its initial condition by resilient means.

ln electromagnetic devices having moving armatures which carry electrical contacts, obiectionable contact bounce may be corrected by reducing the inertia of the armature, or by damping its motion. Correction may be obtained by reducing the inertia of the armature either by actual reduction of its mass or by artificially eiiecting a reduction of the mass oran increase in damping in connection with the armatures operation. The present i11- vention is directed to an improvement of this type.

It is therefore another object of the invention to provide an improved armature structure in a contactor for stabilizing its motion in conjunction with electrical contacts carried by the armature and coacting `with stationary contacts.

The novel features of the invention are set forth with particularity in the appended claims. The invention itself, however, both as to its organization and method of operation, together Iwith further objects and advantages thereof, may best be understood by referring to the following description and the accompanying drawing.

in the drawing FGURE l illustrates an elevation View of a contacter provided with an improved armature construction. FIGURES 2, 3 and 4 of the drawing illustrate the functional operation of the improved structure during its operational phases in overcoming inertia of the armature while at the same time maintaining electrical contact so that a controlled circuit is uninterrupted.

ditiifi Referring now to FIGURE l a frame l1 is provided with a mounting bracket l5 and a winding 12, an armature 16 being hinged against the bracket l5 to move toward the winding l2 when the latter is energized. The armature lo is substantially a rectangular strip; however, the particular shape of this strip is immaterial for the purposes of the present invention and could take many other forms. Attached to the armature le is an inverted, U-shaped bracket 17. A contact arm i9 is provided with contacts Ztl and 22 at each end respectively and with a pin or shaft lit which coacts with and is fitted into the bracket i7. The arrangement of the bracket 17 and the shaft 1S may take several forms also; id est, there may be two brackets 17, one on either edge of the armature l@ with the arm i9 supported by the shaft i8 in the bracket i7 lying between the brackets, or there may be a single bracket i7 having a cutaway portion in the center thereof for permitting the arm i9 to move therein supported by the shaft ld. Contact Z2 has a projecting portion 22a which normally extends partially through the armature lo as indicated in FGURE l. A spring 14 recessed in a well i3 of the winding l2 normally pushes against the projection 22a of the contact 22 thereby urging the armature lr6 avay from the winding l2 through the interaction of the shaft 18, the bracket 17 and the arm l@ and also causes Contact 22 to be positioned against a contact 23, the latter being supported by an arm 23a fixed to an insulating block 24 which is fixed to the bracket l5. The contact 2d is arranged to coact to make electrical connection with a contact 2l carried by a mounting 21a which in turn is iixed to an insulating block Z5. Normally, therefore, contacts Z2 and 23 are closed to permit an electrical circuit to be made While contacts 2d and 2l are open. When the winding l2 is energized the armature lr6 is drawn down, moving with the bracket i7 which bearing upon the shaft 18 carries the arm i9 and its contacts 22. and 2li downward also. Consequently contacts 7.2 and 23 are opened and contacts Ztl and 2l are closed.

When the winding l2 is deenergized the armature 16 is released, and under the urging of the spring 14 the armature Tio and the arm 19, together with its contacts 20 and 22 are forced upwards until contacts 22 and 23 impinge. Referring now to FIGURE 2 it will be noted that when contact 22, urged upwards by the spring ld, iirst encounters contact 23 the shaft i3 will be at its upper extremity within the bracket i7 and the arm i9 will be carried in such a manner that the bent portion holding the contact Ztl impinges against the end of armature 16. Since the armature and its associated assembly have movement upwards as a result of the force of spring ld, the resulting inertia has to be overcome by the force of reaction of contact Z2 against contact 23. Normally there would be a tendency for the contacts Z2 and 23 to rebound as a result of this reactive force; however, any such tendency in the structure shown in the present invention is counteracted as explained hereinafter.

Referring now to FiGURE 3 it will be noted that momentarily the arm i9 has turned counter-clockwise on its shaft i8 which still remains at the upper extremity of the Usl1aped bracket i7' and the projection 22a of contact 2?. now becomes positioned through the hole in the armature i6. As further resistance is encountered between the Contact Z2 and the Contact 23 the arm i9 continues to turn counter-clockwise on shaft i8 until the end or" the arm if) carrying contact 22 encounters the upper surface of armature i6 whereupon the continued pressure between the contacts 22 and 2.3 reverses the direction of rotation of the arm i9 until it rests completely against the upper surface of armature ld, the shaft l moving downward in its relationship with bracket i7.

' the art.

As a consequence of the motions of the armature 16 and its assembly comprising the arm 19, the shaft i3 and the contacts 22 and 2&3, deceleration ot the armature lo is greatly assisted. More important, however, the physical Contact between contacts 22 and 23 remains uninterrupted since any tendency for these contacts to separate is overcome by the flexibility of the armature assembly and brings about a rolling of contact 22 upon Contact 23 as indicated in FIGURES 2, 3, and 4 rather than a bouncing action which is obtained normally in contactors not provided with the structure oi the present invention.

Contactors having normally closed contacts are used frequently on motor control devices and circuits where separate lields are required for starting and where electrodynarnic braking circuits are established when the energizing power for driving is removed. Consequently, the improved structure described above finds widespread use in motor control apparatus, and provides reliable op` erating characteristics in contacter requirements.

While this invention has been explained and described with the aid of a particular embodiment thereof, it will be understood that the invention is not limited thereby and that many modifications will occur to those skilled in it is therefore contemplated by the appended claims to cover all such modiiications as fall within the scope and spirit of the invention.

What is claimed is:

1. In an electromagnetically operated device, a movable armature, a Winding for generating liux to operate said armature, a bearing member on said armature, a shaft coasting with said bearing, an arm ixed to said shaft, a contact at an extremity of said arm, a fixed contact, and a spring seated in a Well in said Winding and passing through an opening in said armature normally urging first said contact against said ixed Contact and biasing the operation of said armature.

2. In an electromagnetically operated device, a movable armature, a Winding for generating iiux to operate said armature, a loose-tting bearing member on said armature, a shaft coacting with said bearing to have play in a plane perpendicular to the plane of said armature, an arm iiXed to said shaft, a Contact at an extremity of said arm, a iixed contact, and a spring normally urging first said contact against said fixed contact and biasing the operation of said armature.

3. In an electromagnetically operated device, a movable armature, a winding for generating iiux to operate said armature, an inverted yU-shaped bearing member on said armature, a shaft loosely tted into said bearing, an arm carried by said shaft, a Contact at an extremity of said arm, a Xed Contact, and a spring seated in a Well in said winding and passing through an opening in said armature normally forcing said contacts together and thereby biasing said armature against operation by said linx.

4. In an electroniagnetically operated device, a mov-` able armature, a winding for generating linx to operate said armature, an elongated bearing member on said armature, a shaft loosely iitted into said bearing, an arm carried by said shaft, a Contact at an extremity of said arm, a fixed Contact, and a spring seated in a well in said winding and passing through an opening in said armature normally forcing said contacts together and thereby biasing said armature against Operation by said iiux.

5., in an electro-magnetically operated device, a movable armature, a winding' for generating linx to operate said'armature, a vertically elongated bearing member on said armature, a statt loosely fitted into said bearing, an arm carried by said shaft, a contact at an extremity of said arm, a fixed contact, and a spring seated in a well in said winding and passing through an opening in said armature normally forcing said contacts together and thereby biasing said armature against operation by said flux.

6. In a contact making and breaking structure comprising a iixed contact and a movable contact normally urged into mutual contact by resilient means, an arm for carrying at its one extremity the said movable contact, a shaft supporting said arm, a sloppy bearing into which said shaft is fitted for pivoting said arm, and a hinged support.

for said bearing whereby after movement of said support opposing said resilient means to break said mutual contact the said contacts are restored by said resilient means Without further interruption by the interaction of said shaft and said bearing and the rotation of said arm.

References Cited in the le of this patent UNETED STATES PATENTS 1,176,569 Kjolseth Mar. 2l, 1916 1,231,412 Murphy lune 26, 1917 2,092,478 Sommermeyer Sept. 7, 1937 2,397,113 Vlglehart Mar. 26, 1946 2,397,228 Young et al. May 26, 1946 2,441,137 De Anthony May l1, 1948 2,943,170 Vradenburgh June 28, 196i)

Claims (1)

1. IN AN ELECTROMAGNETICALLY OPERATED DEVICE, A MOVABLE ARMATURE, A WINDING FOR GENERATING FLUX TO OPERATE SAID ARMATURE, A BEARING MEMBER ON SAID ARMATURE, A SHAFT COACTING WITH SAID BEARING, AN ARM FIXED TO SAID SHAFT, A CONTACT AT AN EXTREMITY OF SAID ARM, A FIXED CON-

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