US1862631A - Switch structure - Google Patents

Description

June 14, 1932. A, PENN 1,862,631

swITcH STRUCTURE Filed July 1e, 1928 @Wwf Patented June 14 1932 UNITED STATES PATENTOFFICE ALBERT PENN, 0I' DES MOINES, IOWA, ASSIGNQB TO PENN ELECTRIC SWITCH DEB MOINES, ICWA, A. CORPORATION 0F IOWA O0., OF

SWITCH BTBUGI'UBE Application led AJ'uly 13, 1928. Serial N0. 293,270.

The object of m invention is to provide a switch structure o simple, durable and comparatively inexpensive construction: v

A further ob]ect of my invention 1s to provide a switch structure in which a pair of contact members are adapted to be separated from each other in a magnetic field whereby the arc formed between the contact members is blown out and thereby quickly extlnguished.

Still a further object is to provide means in such a structure to prevent the are from jumping to the magnet which causes the magnetic field and thereby quickly extinguishing the arc which would otherwise be prolonged as when the arc jumps to the magnet.

A further object is to provide a switch structure so constructed that the capacity of the switch will not be affected by reversal of the wires when connected to the terminals of the switch whereby the switch is more easily connected in an electric circuit without the bother of determining the polarity of the wires and all chance of connecting the switch wrong is thereby eliminated.

More particularly, it is my object to provide a switch structure of the above referred to character in which it is immaterial whether the negative or the positive wire of an electric circuit is connected with either terminal of the switch. Incidentally, the capacity of a switch of the character herein disclosed, is greater when the current flows in one direction through the switch than when it flows in another direction therethrough, providing the permanent magnet is electrically connected with one of the terminals of the switch. It has therefore, been my object to insulate the permanent magnet from such terminall of the switch with the result that the electric wires of the circuit in which the switch is interposed, may be connected with the terminals of the switch regardless of the polarity of the wires whereby the capacity of the switch is at maximum regardless of how the wires are connected.

With these and other objects in view my invention consists in the construction, arrangement and combination of the'various parts of my device, whereby the objects contemplated are attained, as hereinafter more fully set forth, pointed out in my claims and illustrated in the accompanying drawing. Although the invention is susceptible of a variety of embodiments, it is unnecessary to fully describe and illustrated more than one in order to give Va full understanding of the invention both from its structural and functional stand oints. Accordingly, I have illustrated a re erred and desirable embodiment of the invention in the accompanying drawing, in which:

Figure 1 is a side elevation of my switch structure showing it mounted within a casing, the casing being shown in section.

Figure 2 is a sectional view on the line 2-2 of Figure 1.

Figure 3 is a sectional view on the line 3*-3 of Figure 1.

Figure 4 is an enlarged side elevation of a portion of the switch structure showing the circuit being broken and Figure 5 is a diagrammatic view illustrating an arc jumping from a contact to one of the poles of the magnet.

On the accompanying drawing, I have illustrated one embodiment of my invention wherein my construction for reducing the duration of the arc and thereby increasing the capacity of the switch is shown. The switch structure consists of a base 10 having upstanding brackets 12 secured thereto. A supporting member 14 is mounted on the brackets 12 and is formed preferable of insulating material.

A stationary contact 16 is mounted on a Contact bracket 18 on the supporting bar 14. The bracket 18 is held in position with respect to the supporting bar-14 by a screw 20. A nut 22 on the screw 20 serves to allow for the connection of an electric conductor to the screw 20 and thus to the contact 16.

A permanent magnet 24 of the horseshoe type is mountedon the bar 14 and held thereaga-inst by the bracket 18. A sheet of insulating material 26 is positioned between the bracket 18 and the magnet 24 and an insulating bushing 28 surrounds the screw 20 where it extends between the poles of a magnet 24 as clearly shown in Figures 2 and 3 of the drawing. The purpose of the insulating plate 26 and the insulating bushing 28 is very important and will hereinafter be more fully referred to. The poles are necessarily arranged close together so as to intensify the magnetic field as much as possible.

ltovable contacts 30 are mounted on a spring arm 32. The spring arm 32 is connected `with an armature arm 34 which is pivotally mounted on the bar 14. A bracket 36 and pivot pin 38 serve to provide for such pivotal movement. The contacts 30 pass through openings formed in the arm 34.

A stationary adjustable contact 40 is mounted on the bar 14 and electrically connected by a metallic bracket 42 to the screw 20. A contact 42 is secured to the armature arm 34. The armature arm 34 is electrically connected by a iexible cable 44 to a terminal screw 46 to which another wire of the electric circuit in which the switch is included, may be connected by means of a nut 48.

The bracket 42 is provided with an extension 50 adapted to serve as a stop for the armature arm 34. The undersurface of the extension 50 is faced with insulation 52 which is adapted to be struck by a spring shock absorber arm 54 secured to the armature arm 34.

The armature arm 34 is actuated by means of a lever 56 connected thereto by a resilient connection 58. An automatic or hand control device of any kind may be connected with the lever 56 which is pivotally mounted at 60. In Figure l of the drawing, I have illustrated a rod 62 which may be connected with a pressure actuated diaphragm, a float or other type of controlling device.

Movement of the rod 62 in the direction of' the arrow 64. will cause expansion of the spring 58 until such time as the force of the spring will overcome the magnetism of the magnet 24 which tends to hold the armature arm 34 with the contacts 4() and 42 together.

In this position, the contacts 16 and 30 are held together by the spring arm 32 which is sprung slightly away from the armature arm Upon the spring 58 being stretched far enough to move the armature arm 34 in the direction of the arrow 66, the armature arm will immediately be in a weaker magnetic field and the force of the extended spring 58 will cause it to continue to move in the direction ofthe arrow 66 whereby the contacts are opened quickly. The contacts 40 and 42 will open first and these contacts I call the main contacts since they are largest and carry most of the current.

Immediately after the main contacts have been separated, the spring arm 32 will be engaged by the armature arm 34 and the contacts 16 and 30 will be broken in the magnetic field of the magnet 24. As illustrated in Figure 4, the main contacts 40 and 42 have already been separated and the secondary contacts 16 and 30 have just been separated. Their separation causesy the arc 68 which is blown sidewise as indicated, due to the magnetic action of the magnet 24 on the arc. This action is an old principle which has long been recognized.

I have found that in usin my switch for controlling direct current, t at reversal of the wires to the binding osts 20 and 46, makes a considerable di erence in the capaci'ty of the switch. For instance, when the wires are connected one way the capacity of the switch is about tive amperes while reversing the wires will increase the capacit of the switch to about thirty amperes. I wi l attem t to describe the action of the switch where y this difference may be illustrated.

It is well known that the separation of contact points connected in an electric circuit will produce an arc. In such an event the contact points 16 and 30 are roperlyr considered conducting electrodes. lectriclty is conducted through an arc by means of electrons. Electrons are set free from the conducting electrodes by the action of high temperature. In forming an arc by separating electrodes which are carrying current, intense heat is produced at the point of separation, electrons are emitted, and conduction of current takes place across the air space between the electrodes by means of the electron stream. In the case of an are discharge the electron carriers of electricity are emitted at the negative electrode known as the cathode and extend to the positive electrode known as the anode.

Taking for example,'the switch structure herein disclosed, with the exception of omitting the insulating plate 26 and the insulating bushing, the cathode will be the movable or the stationary contact depending upon the polarity of connection in the circuit.

If the switch is connected so that the sta.- tionary contact 16 is the negative or cathode, the arc stream will be blown by the magnetic field of the permanent magnet 24 making the current path through the air gap longer and longer until finally the arc is ruptured. If so, the operation of the switch is satisfactory. The arc stream in being blown aside, however, will touch the face of the permanent magnet as illustrated in Figure 5, since the magnet is close to and electrically connected with the cathode 16.

On account of the fact that the permanent magnet is cold and has relatively high heat receiving capacity, current will not continue to flow between the movable contact and the permanent magnet because of the fact that now the permanent magnet is the cathode and being relatively large, it is not heated to a ktemperature which will give off electrons. Therefore, even though the arc stream should suiciently high temperature.

touch the permanent magnet, the arc will be ru tured.

aking as a further example, the hypothetical switch referred to in the precedmg three paragraphs and assuming the movable contact as the negative or cathode, on opening the switch for breaking the circuit, an arc stream will result and the arc will be blown aside by the magnetic influence of the permanent magnet 24 until it touches the face of the magnet whereupon the magnet will act as the anode and current will continue to flow because we now have a hot cathode, electrons are being emitted and they carry the current across the arc gap to the anode (permanent magnet).

In order for the arc stream to continue, as long as possible during the spreading of the contacts, it is immaterial whether the anode is hot or cold. Therefore, the fact that the permanent magnet is relatively cold makes no difference when the movable contact is the cathode.

In my improved type of switch as described, wherein the permanent magnet 24 is insulated from the stationary contact 16,

the current cannot flow through the permanent magnet. Therefore, interruption of the current is successfully accomplished.

It is, therefore, evident that the behavior of my improved switch is exactly what would be expected from a consideration of the fundamental principles of the action of an electric arc. It has long been known that an arc can be sustained only when the cathode is at may be either hot or cold andv I vhave taken advantage of these principles in my device.

It, therefore, becomes obvious that the insulations 26 and 28 whereby thepermanent either of the sides of the electric circuit, is

The anode magnet 24 is not electrically7 connected with taining said magnet against said base, a stationary contact on said plate between the poles of said magnet and a movable contact engageable therewith.

v 3. In a switch struc-ture, a base, a horseshoe magnet having one side thereof flatwise thereagainst, a plate againstthe opposite side of said magnet, means for retaining said plate against said magnet and thereby retaining said magnet against said base, an-

extension on said plate located between the poles of said magnet, a stationary contact on said extension and a movable contact engageable therewith.

Des Moines, Iowa,` June 29, 1928.

ALBERT PENN.

very necessary if a fool proof switch is to be.

made. By fool proof I mean a switch in which it is immaterial whether the negative or positive wire is connected with the screw v20. As long as the magnet is insulated from either side of the electric circuit, it cannot act either as an anode or a cathode and it is therefore, immaterial which way the wires are connected to the switch.

A great many changes in the structural details can be made in the switch structure which Il have herein described and yet the real spirit and purpose of the invention will not be departed from. It is therefore my intention to cover by my claims, any modied forms of structure or use of mechanical equivalents, which may be reasonably ineluded within their scope.

I claim as m invention:

1. In a switc structure, a base, a` magnet i thereagainst, a plate for retaining lthe magnet in such posltion thereagainst, an extension on the plate between the poles of the lll

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