US3537047A

US3537047A - Electric snap switch

Info

Publication number: US3537047A
Application number: US814138A
Authority: US
Inventors: Rudolf Steiner
Original assignee: Individual
Current assignee: Individual
Priority date: 1969-04-07
Filing date: 1969-04-07
Publication date: 1970-10-27
Anticipated expiration: 1987-10-27
Also published as: GB1249376A

Description

Ocf. 27,1970 R. sTEINEk ELECTRIC SNAP SWITCH Filed April '7, 1969 2 Sheets-Sheet 1 RUDOLF STEINEB INVENTOR.

United States Patent 3,537,047 ELECTRIC SNAP SWITCH Rudolf Steiner, 3624 Inglewood Blvd., Los Angeles, Calif. 90066 Filed Apr. 7, 1969; Ser. No. 814,138 Int. Cl. H01h 51/28 US. Cl. 335-207 12 Claims ABSTRACT OF THE DISCLOSURE A snap action switch having stationary permanent magnets with pole pieces contiguous therewith, the pole Pieces also functioning as electrical contacts, and an armature to bridge said pole pieces to complete a circuit and moveable away therefrom with a snap action to open said circuit.

The subject of this invention is a so-called electric snap switch.

Conventional switches of this description resort to mechanical spring members to attain the snap action which is desired to, firstly, provide a proficient rupture of the electric arc and, secondly, to allow for the switch actuation independently from the operators dexterity. These mechanical springs either carry electric current or are exposed to the heat radiated from adjacent current-carrying switch elements, resulting in spring fatigue, rupture and other malfunctions. The mechanical springs further require preloading before contact-breaking and an excess deflection after contact-making. This causes complex, but operationally useless, pretravel, overtravel and differential-movement conditions. The contact pressure force is usually small because of the adverse mechanical advantage with which it is transmitted from the mechanical spring. Consequently, the contact gaps are small, restricting the magnitude of the load current and the interrupting capacity. The movement of the actuator is not a positive indication of the switch operation. The switches contain a considerable quantity and variety of delicate assembly parts, which is reflected in the complex tooling and manufacture.

Both the design and construction of switches in accordance with this invention constitute the following improved and advantageous characteristics:

A permanent magnet of ceramic and, therefore, electrically nonconductive material provides both the movable contact action and the contact pressure. The latter acts directly at the contacts and is at its maximum value when expected and required to maintain a specific contact position.

A ferrous and, therefore, electrically conductive pole piece having an electric terminal extension is arranged at each pronounced pole of the permanent magnet to direct the magnetic flux toward an armature of, likewise, ferrous and electrically conductive material. Thusly, the armature, once allowed to become attracted by a magnet and a pole-piece pair structure, is capable of closing an electric circuit which is connected across the aforementioned terminals. It becomes apparent that such an arrangement utilizes the major members of the magnetic circuit concurrently for the electric circuit.

The switch actuator engages directly the armature and movable contact, respectively, rendering a highly desirable positive switch action. In this manner, the correct switch operation becomes verified if the actuator can be moved or, conversely, a defect in the movable switch contact becomes noticeable if the actuator can be moved without a snap effect, or not at all.

This feature also obviates the nuisance conditions of a pretravel, an overtravel and a movement differential, together with the requirements therefor.

"ice

The contact arrangement in the switch in accordance with this invention is of the favorable double-break variety which can be had in traditional switches of this kind only through laborious design and at considerable, additional expense.

The need for only a small quantity of basic switch parts and the nonexistence of assembly hardware permits generous contact dimensions within the standardized envelope for switches of this type allowing for the negotiation of large electric current carrying and interrupting capacities.

The presenece of a magnetic field in the electric circuit aids in the quenching of arcs upon contact opening through a blowout action, which is especially desirable for switches operating in direct-current systems.

Further advantages of the subject invention over prior art will become apparent from the following description and the accompanying drawing.

In the drawing, forming a part of this application:

FIG. 1 indicates, in isometric projection, the principal switch members,

FIG. 2 shows in front elevation and cross-section in the plane 11-11, a possible switch assembly within an enclosure,

FIG. 3 is a plan view of the switch as seen in the plane IIIIII,

FIG. 4 is a front view of an enclosed switch,

FIG. 5 is a view of a magnetic structure in front elevation,

FIG. 6 is a schematic bottom view of an ON-OFF switch configuration,

FIG. 7 is a schematic bottom view of an ON-ON configuration,

FIG. 8 is a schematic bottom view of a momentary ON- normally OFF configuration,

FIG. 9 is a schematic bottom view of a momentary OFF-normally ON configuration,

FIG. 10 is a schematic bottom view of single-pole, double-throw, double-break switch configuration, and

FIG. 11 is a schematic bottom view of a momentary ON-OFF-momentary ON switch configuration.

Referring now to the drawing, wherein like reference characters designate like or corresponding parts, and particularly to FIG. 1, portraying only the principal switch parts without a switch enclosure of a, for example, singlepole, two circuit, double-break switch 10, a stationary permanent magnet 12A of electrically nonconductive material is positioned at one end of the assembly 10, whereas another stationary permanent magnet 12B having like properties is arranged at the opposite end of said assembly. Each said permanent magnet has a, for example,

cylindrical hole

13A and 13B, respectively, formed across its thickness along and concentric with its center axis. The pole faces 14A and 16A may be of the magnetic north polarity, while the pole faces 14B and 16B may be of the opposite, magnetic south polarity. A stationary pole piece 18 of ferrous and, therefore, electrically conductive material is placed adjacent to each said polarized

pole face

14A, 14B, 16A and 16B of each respective permanent magnet 12A and 123. Each said pole piece has a first extremity 20, the front face 22 of which serves as the stationary electric contact surface. The pole pieces are positioned in such a manner that the front faces 22 of one magnetic structure face the front faces 22 of the opposite magnetic structure. A second pole piece extremity 24, having a hole 26 formed therein acts as a wiring terminal to which a cable can be soldered. If the hole 26 is tapped, a screw terminal type becomes available in combination with a binding screw 28. The second pole piece extremity 24 can be made as a separate part of magnetically nonconductive material and metallurgically bonded to the pole piece 18. This will preclude a stray flux and magnetic effects external to the switch. A movable armature 30 of ferrous and, consequently, electrically conductive material is arranged between the two

permanent magnets

12A and 12B and their respective pole piece structure faces 22 extending, in length, across a pole-piece pair 1818 of either permanent magnet. A slot 32 is formed in the armature 30, extending from its geometric center to one outside face 34. The switch actuator 36 having two collars 38 formed thereon which are spaced apart from each other for the thickness of the armature 30, is inserted into said armature so as to arrest the latter bewteen the two collars 38 with respect to any axial displacement except for a moderate play which will compensate for pole piece and assembly tolerances. The armature actuator ends 40A and 40B are free to move in an axial direction through the, in this case,

cylindrical holes

13A and 13B of the

permanent magnets

12A and 12B, whereby the actuator ends 40A and 40B extend beyond the outside planes of the

magnets

12A and 12B, respectively. It should be noted that that actuator end which was operated last extends for a lesser length than that which it is available for the next switching engagement.

It appears to be in order to describe the switch operation in view of the drawing in FIG. 1, because the principal switch parts are not obstructed through, however necessary, additional assembly members.

If the armature 30 is in the position shown in FIG. 1, namely, adjacent to the pole pieces 18-18 belonging to the permanent magnet 1213, it closes the magnetic circuit energized by said magnet 12B and becomes and remains strongly attracted to said pole pieces. Concurrently, said armature 30 completes the electric circuit across said pole pieces 1818 prepared through the wiring connections to the terminal extensions 24 of said pole pieces 18. Because the now available magnetic force is at its maximum value, a large contact pressure is imparted. An external, me chanical force exerted on the actuator end 40B in the direction toward the end 40A causes the transfer of the movable armature 30 so as to open the former switch position and to establish the other possible switch position, namely, the closing of the magnetic circuit energized by the permanent magnet 12A with the corresponding and concurrent closing of its electric circuit across the respective pole pieces 1818. Because this armature transfer starts in each case at the maximum force exerted on it by a closed magnetic circuit, the contact opening commences with a sudden so-called snap action, at the escape from the first magnetic field and terminates with, an equally sudden, entry into the second magnetic field, both independently of the operators dexterity. To further assure this rapid action and to preclude a teasing of the contacts during the armature transfer, the

ends

40A and 40B of 'the actuator 36 should extend beyond the switch envelope for a length suitable only for the application of a pushing motion, but not allowing for a pulling of the actuator. The direct actuator engagement with the armature provides a highly desirable positive switch action. In this manner, the operator becomes aware of the armature movement if the actuator can be moved, or he feels a malfunction of the armature and contact transfer if the actuator responds without a magnetic effect, or not at all. Further, the direct actuator engagement with the armature and movable contact, respectively, occurs without any actuator travel preceding or following the movable contact transfer disregarding minute production tolerances and takeups. The double-break feature provided by this switch construction facilitates arc interruption, extends the life of the electric contacts, and permits the interruption of larger currents compared to single-break switch varieties. Correspondingly, advantageous operational causes and effects apply to the other switch varieties enumerated hereafter.

A practical switch construction of the aforementioned type is shown in FIG. 2 and FIG. 3, respectively. The switch frame, in this case an enclosure made of, for example, bakelite, consists of a top 42 and a bottom 44 mating with each other in a horizontal plane IIIIII, located through the axis of the actuator 36. Each stationary part, namely, the two

permanent magnets

12A and 12B, and the four pole pieces 18 are lodged within recesses 46 formed into said top 42 and said bottom 44, respectviely, except for a pole piece type 18A which is illustrated to indicate the appearance and insertion of an electrically-inactive pole piece. The pole piece extremities 24 extend through and beyond the slots 48 formed in the bottom 44 to the exterior of the enclosure, making them accessible for the attachment of cables. A, for example, semicylindrical hole 50 is formed at each side 52 of the top 42 concentric with the axis of the actuator 36. A coacting, in this case semicylindrical hole 54 is formed at each side 56 of the bottom 44, also concentric with the axis of the actuator 36. Upon the completed switch assembly, any two mating semicylindrical holes constitute one fully-cylindrical clearance hole for the passage of one

end

40A and 40B, respectively, of the, in this example, cylindrical actuator 36. The, for example,

cylindrical holes

13A and 13B formed into the respective

permanent magnets

12A and 12B are utilized as bearings for the

ends

40A and 40B, respectively, of the actuator 36. Thusly, the rectangularly-shaped armature 30, being attached to the actuator 36, floats inside of a rectangularly prismatic channel surrounded by two inside surfaces of the switch envelope and two surfaces raised toward the envelope interior with respect to adjacent envelope material wall "thicknesses. Any radial play of the armature within the channel clearance will be beneficial for the establishment of contact engagement points varying from previous ones. An open slot 58 is molded into the upper portion of the top 42 across its width, perpendicular to the actuator axis, and an open slot 60 is arranged correspondingly in the lower portion of the bottom 44. Both these slots are provided and adapted to accommodate mounting screws (not shown) for the switch. The two screws 62 and the nuts 64 required for the assembly of the top 42 to the bottom 44 appear within the through-holes 67 in FIG. 4, lodged within recesses 66 which are molded into the top 42 and bottom 44, respectively, to increase their spacings from the live terminals.

It should be noted that the herein described switch does pending on specific operational switch requirements:

The

permanent magnets

12A and 12B, respectively, can be of ferrous and,-therefore, electrically conductive material. This requires the application of, a comparatively thin, wafer 68 of electrically nonconductive material arranged between each pole of the permanent magnet 12A,

12B, and its adjacent pole piece 18. Such a situation, il-

lustrated in FIG. 5, will be magnetically less efiicient than one having directly mating pole pieces because of the magnetic fluxloss through the wafer gap.

The pole pieces 18 as well as the armature 30 can be plated to resist corrosion and to reduce the contact resistance, respectively.

Each pole piece face 22 can be provided with a round edge instead of the flat edge in FIGS. 1, 2 and 3, to cause a concentration of the magnetic flux and a consequent increase of magnetic attraction of the armature 30'. This, obviously, increases also the snap action. A reduction of the height of each pole piece extremity 20 renders comparable effects.

The actuator 36 can be made with only one of the two

extensions

40A and 40B being accessible from the switch exterior, obviating one of the two through-holes 52-54- of the switch enclosure, requiring one pulling and one pushing action in lieu of the two pushing actions for its operation.

The armature 30 can be made of a permanent magnet of, however, ferrous and electrically conductive material to provide new and additional switch operations and applications.

The pole piece faces 22 and those surfaces of the armature 30, selectively, making contact with said pole piece faces can be equipped with thin layers of magnetically nonconductive but electrically conductive sheet stock. This produces a so-called anti-freeze property resulting in a more sensitive switch actuation at, however, reduced snap-action effect.

Several switches of the described construction can be ganged in side-by-side arrays and in actuator-to-actuator configuration, selectively, to perform specific programs. Assuming that the external actuating means engage all switch actuators with adequate precision, the switch responses will be simultaneous, which is of great significance with multiphase system applications.

A switch in accordance with this invention can be equipped with rubber boots and bellows, selectively, one each arranged between the actuator and the switch surface, respectively, to attain a dustproof switch variety.

A subject switch and a switch gang, selectively, can be mounted inside of a dustproof, waterproof, explosionproof and hermetically-sealed housing, selectively, for engagement through an actuator extending beyond a said housing, whereby said actuator :can be equipped with a boot and bellows, selectively. Conversely, several switches enclosed individually in the aforementioned fashion, can be ganged in a side-'by-side and actuator-to-actuator mode, selectively.

Each snap switch of the herein described varieties can be equipped with an auxiliary external mechanism of the lever, leaf, roller-leaf, plunger-type, and with means for toggle and push-button operation, selectively, for the engagement of the switch actuator with a larger mechanical advantage and to become compatible with specialized controlling means, respectively.

It becomes apparent that the herein described snap switch can be mounted on an open frame adapted to retain its individual parts.

Numerous practical electric applications of the described switch principle are feasible within the scope of this invention. Those configurations which are expected to be especially popular are shown schematically and described in substance, however, without limiting the scope of this invention to these arbitrarily selected samples. It should further be noted that these schematics are simplified switch structure bottom views. This allows for the differentiation between an electrically inactive pole piece and one equipped with a terminal extremityv through the visibility of the material edge, in addition to cable attachments shown where operationally applicable.

A single-circuit switch having one ON and one OFF position is shown in FIG. 6. The OFF position has the electrically inactive pole pieces.

A two-circuit switch having an ON-ON position configuration is illustrated in FIG. 7. All four pole pieces are electrically active and have terminal extensions.

A single-circuit switch having one momentary ON and one normally OFF position is shown in FIG. 8. This variety has two electrically active pole pieces without a magnet at the ON position and a magnet with two electrically inactive pole pieces at the OFF position. An electrically and magnetically nonconductive member 70, simulating a magnet and its bearing holes in dimensions, can be inserted at the ON position.

A single-circuit switch having one momentary OFF position and one normally ON position is portrayed in FIG. 9. This switch has electrically active pole pieces and a magnet at the ON position, and electrically and magnetically inactive pole pieces at the OFF position. Like in the foregoing example, a member 70 can be inserted as shown in FIG. 9.

The switch type likely to be most in demand, namely, a single-pole, double-throw, double-break switch, is shown in FIG. 10. Its function requires one jumper 72 across 6 one terminal of each switch structure, constituting the so-called COMMON-external switch connection. Either of the other two remaining terminals is connected to one of two external circuits. All four pole pieces are magnetically and electrically active.

The example presented in FIG. 11 should merely serve as an introduction to the family of switches using a permanently magnetized armature together with the principal switch structure, to the effects caused thereby and to another possible variety of applications. In the single-pole, two-circuit, double-break switch shown, the two

perma nent magnets

12A and 12B are installed in a like magnetic orientation, N-S, N-S, as is the aforementioned permanently magnetized armature, N-S. Assuming that the magnetic fields generated by these three permanent magnets are reasonably equal, the armature 30- 'will normally be equally repelled by the two stationary outside structures and float between the latter. Only if actuated toward one of the two stationary pole piece pairs, it will close that electric circuit for the duration of the actuation, to be repelled to the neutral center position when the actuating force ceases. This establishes a momentary ON-OFF- momentary ON switch operating characteristic.

It becomes apparent that the herein described and shown switch emodiments are merely of an illustrative nature and that additional configurations, combinations and variations are feasible without departing from the spirit of this invention.

What is claimed is:

1. An electric snap switch comprising:

a frame having operational and mounting apertures formed therein,

at least one structure mounted on said frame adapted to establish a magnetic circuit portion in combination with an electric circuit portion, selectively,

a permanent magnet of an electrically nonconductive material mounted within said structure in contiguous contact with the members of said structure and on said frame adapted to magnetize said struture,

a movable armature of magnetically and electriclly conductive material adapted to close and to open, respectively, said electric circuit portion selectively and concurrently with said magnetic circuit portion, disposed within said frame in a functional relationship with at least said one permanently magnetized structure,

an actuator having two ends, mounted on said armature so as to extend with at least one said end through one said operational aperture of said frame to become accessible from the exterior of said frame.

2. A electric snap switch as defined in claim 1, wherein a permanent magnet of a ceramic magnet material is mounted within and in contiguous contact with the members of said structure.

3. An electric snap switch as defined in claim 1, wherein a permanent magnet of magnetically and electrically conductive material is mounted within and electrically insulated from said structure.

4. An electric snap switch as defined in claim 1, wherein the movable armature of magnetically and electrically conductive material is permanently magnetized so as to have a discrete magnetic orientation.

5. An electric snap switch as defined in claim 1, wherein a first permanently magnetized structure adapted to establish both an open magnetic and an open electric circuit is mounted at a first snap switch position and a second permanently magnetized structure adapted to establish an open magnetic circuit is mounted at a second switch position.

6. An electric snap switch as defined in claim 1, wherein a first permanently magnetized structure adapted to establish both an open magnetic and an open electric circuit mounted at a first switch position and a second permanently magnetized structure adapted to establish both 7 an open magnetic and an open electric circuit is mounted at a second switch position.

7. An electric snap switch as defined in claim 1, wherein a first permanently magnetized structure adapted to establish an open magnetic circuit is mounted at a first switch position and an unmagnetized structure adapted to establish an open electric circuit is mounted at a second switch position.

8. An electric snap switch as defined in claim 1, wherein a first permanently magnetized structure adapted to establish both an open magnetic and an open electric circuit is mounted at a first switch position and an unmagnetized structure adapted to limit the armature excursion is mounted at a second switch position.

9. An electric snap switch as defined in claim 1, wherein a first structure permanently magnetized and polarized in a first orientation adapted to establish both an open magnetic and an open electric circuit is mounted at a first switch position, a second structure permanently magnetized and polarized in a first orientation adapted to establish both an open magnetic and an open electric circuit is mounted at a second switch position and a movable magnetically and electrically conductive armature permanently magnetized and polarized in a first orientation is disposed between said first and said second structure.

10. An electric snap switch as defined in claim 9, wherein said permanent magnet mounted at the first switch position is polarized so as to have a north pole on its first vertical side face and a south pole on its second vertical side face and said permanent magnet mounted at the second switch position is polarized so as to have a south pole on its first vertical side face and a north pole on its second vertical side face.

11. An electric snap switch comprising:

an enclosure of electrically insulating material having a top and a bottom secured to each other, said enclosure having operational and mounting apertures formed therein and recesses molded in its interor,

a permanent magnet of ceramic magnet material and the shape of a rectangular prism having hole formed therein cross its thickness and in the direction of and concentric with its horizontal center axis mounted in a recess of said enclosure at a first switch position, said permanent magnet being polarized so as to have a north pole on its first vertical side face and a south pole on its second vertical side face, selectively a second permanent magnet of ceramic magnet material and the shape of a rectangular prism having a hole formed therein across its thickness and in the direction of and concentric with its horizontal center axis, mounted in a recess of said enclosure at a second switch position, said permanent magnet being polarized so as to have a north pole on its first vertical side face and a south pole on its second vertical side face, selectively,

a pole piece of ferrous and electrically'conductive material moutned within recesses of said housing adjacent to and in contiguous contact with each said north pole and south pole of each said permanent magnet, each said pole piece having a face in a plane perpendicular to the axis of said permanent magnets and oriented toward the housing interior, each said pole piece having an extremity extending into a slot formed into said housing bottom and beyond said slot to the exterior of said housing, selectively, each said pole piece extremity extending through said housing having electrical terminal means,

a movable armature of ferrous and electrically conductive material having a profile to clear the profile of the switch housing interior space provided between said pole piece faces adapted to float within said interior space and to mate with both said pole piece faces adjacent to either of said permanent magnets concurrently, said armature having a slot formed therein extending from its center axis to its periphery,

an actuator of electrically nonconductive material having two ends, and two collars formed thereon near its center and concentric with its longitudinal axis mounted within said slot of said armature, said armature being positioned between said two collars, being spaced apart from each other so as to provide a clearance between the annular inside faces of said collars and the outside faces of said armature, the first said end of said actuator extending through said hole formed within said first permanent magnet and said hole formed in said first enclosure side to the exterior of said housing, the second end of said actuator extending through said hole formed within said second permanent magnet and said hole formed in said second enclosure side to the exterior of said housing.

12. An electric snap switch as defined in claim 11, wherein said extremity of each said pole piece is a member made of a magnetically nonconductive and electrically conductive material, said member being mechanically attached and metallurgically bonded to said pole piece, selectively.

References Cited UNITED STATES PATENTS 3/1965 Crissinger et al 335-205 l/ 1968 Leinauer et a1.

U.S. Cl. X.R.