US3259810A

US3259810A - Electromagnetic switching devices

Info

Publication number: US3259810A
Application number: US326633A
Authority: US
Inventors: Robert A Williams
Original assignee: Talon Inc
Current assignee: Talon Inc
Priority date: 1963-11-27
Filing date: 1963-11-27
Publication date: 1966-07-05
Anticipated expiration: 1983-07-05

Description

July 5, 1966 w s 3,259,810

ELECTROMAGNETIC SWITCHING DEVICES Filed NOV. 27, 1963 INVENTOR.

19- %0eW/a%%'//mm 4 7 BY United States Patent 3,259,810 ELECTRGMAGNETIC SWITCHING DEVICES Robert A. Williams, Fort Worth, Tex., assignor to Talon, Inca, Meadville, Pa. Filed Nov. 27, 1963, Ser. No. 326,633 4 Claims. (Cl. 317172) This invention relates to electromagnetic switching devices. The invention is applicable to various types of switching devices wherein an armature is driven by electromagnetic action and the armature or devices carried by it perform contact making or breaking functions in an electrical circuit or circuits. The invention is particularly applicable to devices wherein the contact making or breaking functions are performed quite rapidly and continuously, for example, a D.C.A.C. chopper. Further, the invention is especially applicable to miniaturized devices wherein it is desirable to achieve high performance characteristics with very limited available input power and space.

The general object of my invention is to provide improved electromagnetic switching devices of the types above-mentioned.

Another object is to provide such improved switching devices which when miniaturized will provide normal operation even in an environment where they are subjected to heavy shock and vibration.

Another object is to provide such improved switching devices which utilize available input power so effectively as to achieve high performance characteristics even when made in very small sizes.

These and other objects are effected by my invention as will be apparent from the following description taken in accordance with the accompanying drawing, forming a part of this application, in which:

FIG. 1 is a schematic longitudinal section view of an electromagnetic switching device in accordance with a preferred embodiment of my invention;

FIG. 2 is a plan view of the device of FIG. 1;

FIG. 3 is an end elevational view of the device of FIG. 1; and

FIGS. 4 and 5 are respectively fragmentary end elevational and plan views illustrating one type of switching arrangement that may be utilized with the device of FIG. 1.

Referring now to the drawing, there is shown an electromagnetic switching device including a drive coil assembly 11, upper and lower

permanent magnet bars

13, 15, a. left end piece 17, a right end piece 19, and an armature assembly 21.

The armature assembly 21 includes an armature 23 shown as a tubular member made of magnetic material. Disposed within and fixed to the armature adjacent its right end portion is a disk 25 of non-magnetic insulating material. Supported by and fixed to the disk 25 and disposed coaxially of the armature and extending outwardly therefrom is a rod or reed 27 which may carry a contact or contacts to perform contact making and breaking functions as will be hereinafter explained. The armature 23 is mounted on pivots 28 for pivoting about the transverse axis indicated by the at 29 in FIG. 1.

The coil assembly 11 includes a spool 31 of non-magnetic material upon which a winding 33 is disposed, the winding being provided with input leads 35 to be connected to a suitable power source (not shown). The

spool 31 is fixed by any suitable means, such as indicated by angle brackets 37 in FIG. 1, so that the spool bore 39 is coaxial with the armature 23 when the latter is in its neutral position. Thus, the coil 33 is so disposed relative to the armature 23 that alternate north and south poles (indicated in FIG. 1 by N-S and S-N) will be created at the armature left and right end portions when the coil 33 is energized by a suitable alternating current power source.

The left end piece 17 is a disk of magnetic material having a cylindrical protrusion 41 extending inwardly therefrom and coaxial with the spool bore 39, and with the protrusion 41 extending within the armature left end portion; the cylinder diameter being slightly less than the adjacent armature portion inside diameter, so as to provide operating clearance.

The right end piece 19 is a disk of magnetic material having a central bore 43 surrounding the armature right end portion, the diameter of this central bore being slightly greater than the outer diameter of the adjacent armature portion so as to provide operating clearance.

The left and

right end pieces

17, 19 are held in fixed spaced relation by the

permanent magnet bars

13, 15, which are received at their respective end portions by respective slots 45 in the end pieces.

The

permanent magnet bars

13, 15, as shown by FIG.

1 are arranged so that their ends are oppositely poled.

As shown, the left end portion of the upper permanent magnet bar 13 is a south pole, while the left end of the lower permanent magnet bar 15 is a north pole. Now as a practical matter, the armature 23 is always in either its clockwise or its counterclockwise position, or is in motion toward one of these positions. When in the clockwise position, the lower left armature end portion is abutting the lower portion of the left end piece protrusion 41 while the armature lower right end portion is abutting the lower portion of the right end piece bore 43. When in the counterclockwise position, the armature upper left end portion is abutting the upper portion of the left end piece protrusion 41 while the armature upper right end portion is abutting the upper portion of the right end piece bore 43' Now the left and

right end pieces

17, 19 are made magnetically integral with the

permanent magnet bars

13, 15, so that there is no gap or disruption of the magnetic circuits at the junctures of same. When the armature 23 is in the theoretical neutral position (coaxial with the coil spool bore 39) the magnetic effects of the

permanent magnet bars

13, 15 are theoretically equal and opposite and therefore cancel out. It is important, however, to understand that when the armature 23 is at or near one of its terminal positions (clockwise or counterclockwise) the magnetic effects of one permanent magnet bar are predominant and the effects of the other can for practical purposes be ignored. This means that when the armature is at or near its clockwise position the lower permanet magnet bar 15 is predominant and there is a magnetic circuit extending around a loop including the lower permanent magnet bar 15, the lower portions of the

end pieces

17, 19, and the armature 23, with the permanent magnet polarity of north at the left end adjacent the armature and south at he right end adjacent the armature. When the armature 23 is in its counterclockwise position, the situation is reversed, with the upper permanet magnet 13 then predominant and the permanent magnet polarity of south at the left end adjacent the armature and north at the right end adjacent the armature. As hereinbefore stated, when the coil 33 is energized from an alternating current power source north and south magnetic poles are alternately established at the end portions of the armature 23,

In operation, assume that the armature 23 is at rest in its clockwise position. Then assume that the coil 33 is energized from an alternating current source and at a given instant a north pole is established by the coil at the left end port-ion of the armature 23 while a south pole is established at its right end portion. These poles will be instantly repelled by the adjacent permanent magnet poles so that the armature 23 moves toward the counterclockwise position. As the armature approaches the counterclockwise position, it will be attracted by the adjacent permanent magnet poles. Thus the armature 23 is both pushed and pulled from the clockwise to the counterclockwise position.

Then on the next half cycle of the alternating current coil energizing source, the polarity of the armature ends will reverse so that the left end is now a south pole and the right end a north pole. The armature 23 will then be repelled by the adjacent permanent magnet poles and will then move toward the clockwise position. As the armature 23 approaches the clockwise position, it will be attracted by the adjacent permanent magnet poles. Thus, the armature is both pushed and pulled from the counterclockwise to the clockwise position. This process is repeated at the frequency of the alternating current coil energizing source.

The effect of the above-described structure and arrangement is advantageous in several respects. It results in a positive snap-like action of the armature 23 in its movement from one position to another. This armature action of course also becomes the characteristic of the switching or contact element or elements that are carried by the armature. Thus, the tendency to contact bounce is effectively resisted, and normal operation persists even in environments involving heavy shock and/ or severe vibration. Furthermore, the above-described structure and arrangement achieves very effective utilization of available power in minimum space and is consequently admirably suited to miniaturization techniques.

It should be apparent from a careful consideration of the foregoing that in essence, the structure and arrangement of the present invention contemplates the following: Providing means for producing a first set of magnetic poles having alternately a first and a second polarity at spaced locations on opposite sides of the pivot on a pivoted structure (for example an armature), permanent magnet means producing a second set of predominant poles adjacent said first set when said pivoted structure is in a first terminal position and while said first set has said first polarity (clockwise or counterclockwise) said second set of poles being of polarity such as to produce a first repelling force couple on said pivoted structure tending to push said structure toward its second terminal position (counterclockwise or clockwise), permanent magnet means for producing a third set of predominant poles adjacent said first set as said pivoted structure approaches said second terminal position, said third set of poles being of polarity such as to produce a first attracting force couple on said pivoted structure (while said first set still has said first polarity) tending to pull said structure toward said second terminal position so that when said first set of poles assumes its second polarity a repelling force couple will be produced to push said pivoted structure back toward its first terminal position and as it approaches same an attracting force couple will act to pull same toward said first terminal position, the cycle being repeated at the frequency of the cycle of change of polarity of said first set of poles.

In the preferred embodiments of the invention, the said first set of poles having alternately a first and a second polarity is produced by means of a suitably disposed winding or coil energized from an alternating current power source and the second and third sets of predominant poles are produced by oppositely poled permanent magnets. Further, in accordance with preferred embodiments of the invention the poles at one end portion of the permanent magnet structures are disposed on opposite sides of and exteriorly of said pivoted structure and the poles at the other end portion of the permanent magnet structures are disposed on opposite sides of and interiorly of said pivoted structure.

It is apparent that the details of structure of devices embodying the principles of my invention may take many different forms. Further, details of structure such as various armature pivot mounts, drive coil mounts, switch ing element configurations, frame structures, encapsulating techniques, and the like, belong to the prior art and are therefore not labored herein. For such details of some electromagnetic switching devices of the general type to which the present invention is applicable, reference is made to my United States Patent Numbers 2,959,648 and 3,172,975.

For completeness, one form of switching element which may be utilized in a device embodying the principles of my invention is shown by FIGS. 4 and 5. There, a conductive contact shorting element 47 is fixed to the rod or reed 27 which is in turn carried by the armature 23. The shorting element 47 acts to bridge between the

contacts

49, 51, thereby opening and closing the electric circuit containing the

contacts

43, 51 at the frequency at which the armature 23 is driven.

The foregoing disclosure and the showings made in the drawing are merely illustrative of the principles of this invention and are not to be interpreted in a limiting sense.

I claim:

1. An electromagnetic switching device comprising:

(a) a pivoted structure mounted for oscillatory pivoting movement about a pivot axis;

(b) means for producing a first set of magnetic poles having alternately a first and a second polarity at spaced locations on opposite sides of said pivot axis;

(c) permanent magnet means producing a second set of predominant poles adjacent said first set when said pivoted structure is in a first terminal position and while said first set has said first polarity, said second set of poles being of polarity such as to produce a first repelling force couple on said pivoted structure tending to push said structure toward a second terminal position;

(d) permanent magnet means producing a third set of predominant poles adjacent said first set as said pivoted structure approaches said second terminal position, said third set of poles being of polarity such as to produce a first attracting force couple on said pivoted structure while said first set still has said first polarity, said attracting force couple tending to pull said pivoted structure toward said second terminal position;

(e) so that when said first set of poles assumes its second polarity a repelling force couple is produced to push said pivoted structure back toward said first terminal position and as it approaches same an attracting force couple acts to pull same toward said first terminal position, with the cycle being repeated at the frequency of the cycle of charge of polarity of said first set of poles.

2.. The invention in accordance with claim ll, wherein said first set of poles is produced by a coil to be energized from an alternating current power source and said second and third sets of poles are produced by oppositely poled permanent magnet structures.

3. The invention in accordance with claim ll, wherein said second and third sets of poles are produced by oppositely poled permanent magnet structures and the -to actuate a separate control device at substantially the 10 poles at one end portion of the permanent magnet struc- References Cited by the Examiner tures are disposed on opposite sides of an exteriorly of UNITED STATES PATENTS said pivoted structure and the poles at the other end portion of the permanent magnet structures are disposed On 3,177,412 4/1965 Carlson 317173 opposite sides of and interiorly of said pivoted structure. 5

4. The invention in accordance with claim 2 which OTHER REFERENCES includes means operatively connected to said pivoted Perret, German Application No. 1,066,658, published structure for movement through a given are in response Oct. 8, 1959.

to the oscillatory movement of said structure, said means BERNARD A GILHE ANY Primary Examiner same frequency as said alternating current power source. HARRIS, Assistant Examiner-

Claims

1. AN ELECTROMAGNETIC SWITCHING DEVICE COMPRISING: (A) A PIVOTED STRUCTURE MOUNTED FOR OSCILLATORY PIVOTING MOVEMENT ABOUT A PIVOT AXIS; (B) MEANS FOR PRODUCING A FIRST SET OF MAGNETIC POLES HAVING ALTERNATELY A FIRST AND SECOND POLARITY AT SPACED LOCATIONS ON OPPOSITE SIDES OF SAID PIVOT AXIS; (C) PERMANENT MAGNET MEANS PRODUCING A SECOND SET OF PREDOMINANT POLES ADJACENT SAID FIRST SET WHEN SAID PIVOTED STRUCTURE IS IN A FIRST TERMINAL POSITION AND WHILE SAID FIRST SET HAS SAID FIRST POLARITY, SAID SECOND SET OF POLES BEING OF POLARITY SUCH AS TO PRODUCE A FIRST REPELLING FORCE COUPLE ON SAID PIVOTED STRUCTURE TENDING TO PUSH SAID STRUCTURE TOWARD A SECOND TERMINAL POSITION; (D) PERMANENT MAGNET MEANS PRODUCING A THIRD SET OF PREDOMINANT POLES ADJACENT SAID FIRST SET AS SAID PIVOTED STRUCTURE APPROACHES SAID SECOND TERMINAL POSITION, SAID THIRD SET OF POLES BEING OF POLARITY