US2876307A - Switch member - Google Patents

Description

United'States Patent SWITCH MEMBER Woodrow W. Crissinger, Gallon, Ohio, assignor to North Electric Company, a corporation of Ohio Application December 4, 1953, Serial No. 396,127

6 Claims. Cl. 200-87) The present invention relates in general to a novel swrtchmg unit, and particularly to a novel switching unit which utilizes magnetic means for effecting armature operation, and also for accomplishing arc blowout action for associated contact members as operated by the movable armature.

The provision of a. switch member which is operable under conditions wherein severe shock and vibration forces of excessive values are applied to the switch has consistently been a problem in the industrial and military fields. A novel type switch member which affords a solution to these and other problems has been provided in my copending applications including Serial No. 273,296 which was filed February 25, 1952, now Patent No. 2,793,265, issued May 21, 1957; Serial No. 348,750, which was filed April 14, 1953, now Patent No. 2,809,249, issued October 8, 1957; Serial No. 347,193, which was filed April 7, 1953. These several applications were assigned to the assignee of this invention.

The switch members set forth in these applications have varied utility and application, each switch having a preferred application in accordance with its inherent operating characteristics and the field problems which are solved are a result thereof. The basic structure of the switches, in each instance however, comprises means for providing at least a pair of magnetic fields, an armature, and an actuator member physically independent of the armature for varying the influence of the fields on the armature to control the movement and the positioning thereof. With operation of the actuator member between its given positions, the armature is caused to move between preassigned positions in a snap action-like movement. Once the armature has moved to a new position, the magnetic field which is effective in moving the armature thereto is also operative to hold the armature thereat with a strong holding force, and in certain embodiments, the other magnetic field of the pair restrains the actuator in its new position. Contacts for the switch are operated by the armature with the movement thereof between its several positions.

The switches set forth in the copending applications are unique in that they provide a means for actuating an armature within an inflexible and hermetically sealed enclosure. The switches in addition to providing reliable operation are simple and practical in construction, and of an increased life expectancy which is not experienced with known types of hermetically sealed switches. These improved operating characteristics are inherent in each of the switches previously disclosed, and are also included in the switch of the present disclosure.

- -In the use of these switcheswith certain types of equipment, such as in the use of the switch to repeatedly es.-

tablish and interrupt power circuits having a fairly large.

current carrying capacity, it is essential that the contact structure be such that trouble free service and maximum Contact life are established; This is, of course, particularly true in the case of hermetically sealed switch "ice structures, which are intended to operate for lengthy periods of time without disassembling the switch structure.

The present invention is directed to a new and novel switch structure which includes a magnetic blowout means for effecting a reduction in the wear and burning of the switch contact members.

A novel attribute of the arrangement is the manner in which the magnetic field producing means which are utilized in efiecting armature actuation also provide the magnetic blowout protection for the contact members, whereby a minimum of additional equipment is utilized in providing a switch of superior operating characteristics.

The switch of the present disclosure is further novel in its embodiment of a new mounting arrangement for the magnet field producing members, and its inclusion of a new and novel armature and contact controlling arrangement.

It will be apparent from the description hereinafter that the features and advantages of the arrangement set forth herein may be readily included in the switches of the copending applications, either in the manner shown herein, or in a modified embodiment which will be apparent to those skilled in the art.

Other features and advantages of the arrangement will be found in the specific details of the novel switches set forth in the following descriptions and drawings in which:

Figure l is a perspective view of the switch member components, and the relative positioning thereof; and

Figures 2 and 3 are side views of the novel switch member illustrating the responsive positions of the armature and contact members with the actuator moved to its several positions.

General description The magnetic blowout arrangement basically comprises pole means for extending to the operating vicinity of the contact members, the fields of the permanent magnets which are used to effect-actuation of the switch armature. Thus, when an arc is formed as a result of the movement of the armature to open the contacts, the magnetic field of the arc, and the magnetic field of the pole means react so as to increase the arc length. As a result of the lengthening of the arc in this manner, the extinguishing action is extremely rapid, and wear and burning of the contacts is greatly reduced.

Basic switch structure The switch member in each embodiment basically comprises a magnetic armature 10 pivotally mounted between a first permanent magnet 12 and a second permanent magnet 14.

The armature member 10 may comprise a two sectioned rectangular shaped member having its magnet abutting end made of a magnetic material and the reexternally of the housing physically independent of the armature. v

The actuator member may assume any convenient form and accordlng to one embodiment shown in the drawings, comprises a U-shaped actuator of magnetic material mounted with its legs extending along the exterior sides of the housing (not shown), with a pivot mounting for the legs located at the approximate balance point of the actuator. The under side of the base may be of a V- shaped configuration to permit presentation of a fuller base surface to the magnets as the base is moved adjacent thereto. A handle located on the base of the actu' ator facilitates movement of the actuator to its positions of rest with the base located alternatively adjacent the pole-piece 12, or the pole-piece 14.

As shown in Figure 2, with movement of the base end of the actuator 16 to bring same to rest adjacent to the pole-piece 1d, the fields of the magnets 12 and 1d are altered relative to the armature lid to influence same to move its free end to a position adjtcent the magnet 12. The magnet 12 holds armature 1G in its ne= y assumed position, and the magnet 14 holds the actuator 16 securely in its newposition as moved thereto.

With movement of the actuator 16 to its position adjacent the magnet 12 (Figure 3), the fields of the magnets 12 and 14 are altered to move the free end of the armature to a position adjacent the magnet 14 (Figure 3). The static field of the permanent magnet 14 holds the magnetic armature 10 adjacent thereto, and the static field of the permanent magnet 12 holds the actuator 16 securely in the position adjacent thereto.

According to the invention, the armature 16 in its move ments between its two stable positions controls the operation of contact spring 18 into and out of engagement with a fixedly positioned contact 20, to thereby interrupt and complete an associated electrical circuit illustrated generally at 22. As shown in the drawings, the armature contact spring may assume a flattened V-shape form, one end of which is adapted to be secured by suitable fastening means, such as the illustrated nonconductive screw 24, to the base end of the armature member 16. An insulating strip member 26 is located between the armature spring 18 and the armature 10.

The second or contact making end of spring 18 is cylindrically shaped and is disposed to engage a fixed contact spring with movement of the armature to its position adjacent pole 12.

The fixed contact member 20 is secured substantially centrally of the base of magnet 14 by nonmagnetic means, such as the screw means illustrated at 28, with an insulating member 30 being disposed between the contact spring 20 and the magnet 14. The contact making end of spring 20 is also cylindrically shaped and the spring is mounted so that the cylindrical surface will engage the like surface of the movable contact 18 as it is moved thereagainst. In this manner, a wiping action is experienced as the contacts are closed and opened and the possibility of sticking of the contacts is considerably minimized. Further, the flexing of the contact spring 18, as will be seen in Figure 2, is such that with the application of any forces to the switch which may tend to dislodge the armature from its position adjacent the magnet 12, the flexible contact 18 is actually urged into firmer engagement with the fixed contact member 20.

The magnetic blowout field producing means may comprise L-shaped pole-pieces, such as shown at 33 and 34 in Figure 1. The pole pieces 33 and 34 which are of magnetic material are attached to opposite ends of the magnet 14 with their inward ends disposed in opposed relation to eifect an air gap in which the contacting surfaces of the spring members 18 and 20 respectively are brought into engagement. The pole-pieces may be arranged to overlap the armature facing surface of magnet 14, as shown in Figures 2 and 3, and the inward face is angled as shown to permit the armature to engage the pole-pieces on a more full surface as it is moved adjacent thereto. Pole- pieces 35 and 36 for the respective ends of magnet 12 are similarly shaped. The pole-pieces 33-36 inclusive are of a magnetic material and may be Movement of the armature between its two stable positions is accomplished by reducing to a release point, the magnetic field of the particular permanent magnet means which is $1 ectively holding the armature at the time, and

simultaneously rendering the'field of the other permanent magnet effective relative to the armature.

Briefly, with the actuator 16 in the stable position wherein its free end lies adjacent the magnet 14, the free end of the armature member 16 will be in its position adjacent the magnet 12, and a firm stable position is provided for the actuator 16 and armature 14 by the fields of the adjacent magnets 1d and 12 respectively.

In this position, the armature will have moved the rounded end of the movable spring member 18 into firm engagement with the rounded end of the fixed contact 21 to close a point in the circuit 22.

As the magnetic actuator 16 is now manually displaced from its position adjacent the magnet 14 toward its position adjacent the magnet 12 (Figure 3), the flux distribution alters so that more and more flux from the magnet 14 threads the armature 1t Simultaneously, the flux from the magnet 12 which is threading the armature 10 is being reduced by the fact that the actuator 16 has provided an alternate path for the flux emanating from the magnet 12. As the magnetic actuator 16 approaches the magnet 12, the flux distribution is gradually shifted to a point where the magnet 14 exerts a greater tractive force on the armature 10 than the magnet 12, whereupon a very. speedy transfer of the armature from its position adjacent the magnet 12 to its position adjacent the magnet 14 is effected. The movement of the armature is of a snap-action characteristic due to the greater than linear build up of the actuating force on the armature 10 for each progressive increment of the motion of the actuator towards its'other stable position.

It is of course obvious that with the snap movement of the armature It) to its new position, the rounded end of spring member 18 is wiped across the rounded surface of the fixed member 20 and pulled away in a clean breakaway movement. Inasmuch as the opening of the current-carrying contacts is effected within the field provided by the pole- piece 33 and 34, the magnetic field of any are produced reacts with the magnetic blowout field in such a'manner as to increase the arc length. As a result of the lengthening of the arc in this manner, the extinguishing action is extremely rapid, and the wear and burning of the contacts normally effected by an .arc of this type is greatly reduced.

The actuator 16 must move a substantial distance from its rest position in the direction of its new position before the armature 16 will be attracted to its new position. With reference to Figure 2, it will be apparent therefrom that with movement of the actuator 16 toward magnet 12, the actuator 16 is moved a substantial distance from magnet 14 before the armature 10 will move to open the contacts 18, 20. Thus, since the actuator is removed a substantial distance from magnet 14 at the time the armature responds to open the contacts 18, 20, it will have little shunting effect on the magnet 14, and a correspondingly increased field will be provided by pole- pieces 33 and 34 for the purpose of effecting magnetic blowout action for the contacts as opened.

Conclusion The arrangement is such that maximum results are:

obtained with a minimum of equipment. Permanent magnet 14, for example, is operative to accomplish three independent functions (a) attract armature 10 as actuator 16 is moved therefrom, (b) hold armature 10 or actuator 16 stable as moved to a position adjacent there to, (0) provide a blowout field for contact protection.

The arrangement of the invention, of course, lends itself to use with the switch members of the copeuding applications and with various combinations thereof.

While there has been described what is regarded to be a preferred embodiment of the invention, it will be apparent that various changes, rearrangements and modifications may be made therein without departing from the scope of the invention, as defined by the appended claims.

What is claimed is:

1. A switch member for controlling associated electrical circuits comprising a first permanent magnet member and a.second permanent magnet member mounted in a given spaced relation, an armature member of a magnetic, nonpermanent magnet type material pivotally mounted between said permanent magnet members for movement to positions adjacent alternative ones of said permanent magnet members, contact members operable into and out of contacting relation with one another by movement of said armature between its positions, a pair of pole-pieces for at least one of said magnet members mounted with the ends of the pole-pieces disposed in opposed relation to provide a field therebetween, means for positioning the contact closing and interrupting surfaces in said pole-piece field, and an actuator of a high permeability material operable to provide a preferred path for the flux of a magnet as moved adjacent thereto to accomplish armature actuation.

2. A switch member as set forth in claim 1 which includes means on said armature for effecting closure of said contact members with movement of said actuator member adjacent the magnet associated with said polepiece members.

3. A switch member for controlling associated contact members in the opening and closing of electrical circuits comprising first and second magnet members mounted in spaced parallel relation, an armature member pivotally mounted with at least a portion thereof disposed within the zone defined by said magnet members, an actuating member mounted for movement adjacent alternative ones of said magnet members to control movement of said armature between alternate positions adjacent said magnet members, at least a pair of contact members, means for connecting one of said contact members to said armature, and electrically nonconducting means for supporting the second contact on one of said magnet members for engagement by said first contact member with movement of said armature to one of its positions.

4. An arrangement as set forth in claim 3 in which said first contact member comprises a V-shaped springlike member havin one end attached to the base of said armature, and its second end extending substantially the length of the armature in spaced relation thereto.

5. An arrangement as set forth in claim 3 which includes means for controlling said contacts to open with movement of the actuator to effect movement of the armature to its position adjacent the contact-mounting one of said magnets.

6. Control means comprising an armature member having at least a common portion thereof movable between several given positions, static magnetic force producing means at each position operative to apply a holding force to said common portion of the armature at such position as moved thereto, and being of a value sufficient to independently move the armature to its associated position whenever the force holding the armature at another position is substantially reduced, actuator means operative to shunt the holding forces for the armature at each position as moved thereto to permit snap action attraction of said common armature portion by the static force producing means at a different position, a contact set operable into and out of contacting relation wtih one another by movement of said armature between its positions, and means for supporting the contacting portion of said set within the influence of the field of said static magnetic force producing means to minimize arcing thereacross.

References Cited in the file of this patent UNITED STATES PATENTS Re. 16,940 Massa Apr. 24, 1928 692,217 Sundh Jan. 28, 1902 1,048,366 Smith Dec. 24, 1912 1,422,923 Campbell a July 18, 1922 1,738,540 Replogle et a1 Dec. 10, 1929 1,816,894 Burnham Aug. 4, 1931 1,862,631 Penn June 14, 1932 1,891,568 Morris et al Dec. 20, 1932 2,250,016 Garner July 22, 1941 2,632,820 Gauvreau Mar. 24, 1953 2,641,664 Knutson June 9, 1953

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