US2647177A

US2647177A - Double break switch

Info

Publication number: US2647177A
Application number: US146259A
Authority: US
Inventors: Alfred J Huck
Original assignee: Knapp Monarch Co
Current assignee: Knapp Monarch Co
Priority date: 1950-02-25
Filing date: 1950-02-25
Publication date: 1953-07-28
Anticipated expiration: 1970-07-28

Description

July 28, 1953 A. J. HucK DOUBLE Baux surfen Filed Feb. 25. 1950 Patented July 28, 1953 Douane BREAK swrrcn Aurea J. Huck, si. Louis, M6.. mmmto Knapp- Monarch Company, St. Louis, Mo., a corporation of. Delaware Application February 25, 1950. Serial No. 146,259

This invention relates to a double break switch and more particularly to a simple and novel modification which converts a single break switch into a double break switch.

A double break switch when used with electrical appliances is so arranged that one set of contacts are in one side of the supply line and the second pair of contacts are in the second side of the supply line. Where exposed electric elements are used, it is desirable to use double break switches because when the switch is off the exposed electric element is then completely disconnected from both sides of the electric circuit. It is particularly desirable to use double break switches on present day electrical appliances because Underwriters Laboratories have been very insistent that electrical appliances such as stoves and heaters which use exposed element coils, should incorporate double break switching so that a person will not obtain a shock by contacting the cold element coil, which with single break switching would still be connected to one side of the supply line.

In conventional double break switches, both sets of contacts break at the same time, and both sets are subject to deterioration from arcing. Furthermore, since double break switches generally have more parts than do single break switches, the double break switches are generally of larger size than are the single break switches.

There is also a substantial price diil'erential between conventional double break switches and single break switches. For example, double break switches, at present, cost approximately 28 each in production quantities while single break switch, exemplified by the type described hereinbelow, cost approximately 1l.

Thus, one of the objects of this invention is to provide a novel and simple modiiication for converting a single break switch into a double break switch.

Another object of this invention is to provide a novel double break switch in which only one set of contacts is subjected to deterioration from arcing.

Another object of this invention -is to provide a double break switch in which one means is used tobreak one set of contacts, a second means is used to break the second set of contacts, and

both means are actuated by a single control element.

A further object of this invention is to provide a double break switch in which one means is used to break one set of contacts, a second means is used to break the second set of contacts, and

in which the making and breaking of one set of contacts occur prior to or after the making and breaking of the secondvset of contacts.

Still another object of this invention is to provide a double break switch which is generally no larger in size than a simple single break switch.

A still further object of this invention is to provide a double break switch which is novel in construction and is relatively inexpensive to make.

Further objects and advantages of this invention will become apparent as the following description proceeds and the features of novelty which characterize this invention will be pointed out with particularity in the claims annexed to and forming part of this specification.

A preferred embodiment of the invention is shown in the accompanying drawing, in which- Figure 1 is a top plan view of a double break switch which incorporates in a single break switch the novel modification which converts the single break switch to a double break switch;

Figure 2 is an enlarged cross sectional view of the double break switch in Figure 1 taken substantially on line 2-2 of Figure 1, showing the switch in the off'position;

Figure 3 is a view similar to Figure 2 showing the switch in the on position;

Figure 4 is a view of the double break switch taken substantially on line 4 4 of Figure 1;

Figure 5 is a bottom view of the double break switch taken on line 5--5 of Figure 4, showing diagrammatical the wiring arrangement of a circuit in which the switch is used; and

Figure 6 is a cross sectional view of the switch taken substantially on the line 6-6 of Figure 2.

Referring to the drawings, there is shown a reference character B to indicate generally a base and a T for a toggle lever. The base B is usually made of porcelain or the like and the toggle T is also made of an insulating material.

The base B is substantially cup-shaped and has formed integrally therein a plurality of internal mounting shoulders II. These mounting shoulders il partially bound within the cup-shaped base B a pair of cavities, which will be referred to as upper cavity I2 and lower cavity I3. The lower cavity I3 is of smaller cross sectional area than the upper cavity I 2. The single break switch comes equipped with a pair of terminals with internal and external contact points. The internal terminals I4 are strips of metal mounted vertically in the lower cavity I3 of the base and having edges adapted to be clasped by a contacting member. The internal terminals I4 are sup- 3 ported on shoulders II and are electrically connected to external terminal strips I5 by means of screws I6. The external terminal strips I5 are equipped with terminal screws I'I.

Also mounted on support shoulders II is a support member S having a vpair of flanges I8 extending upward within the upper cavity I2. The toggle lever T has mounted therein an insert I8 of substantially thick sheet metal; This insert Il extends from toggle T into the upper cavity I2 of the base B. The insert I9 has a pair of lugs extending therefrom which lugs 20 enter holes 2| in flanges I8 so as to position and support toggle T. The extended end of insert I9 is cut out to receive a bifurcated element 22 and to form therewith a toggle joint.

A U-shaped electrically conducting member 23 is pivotally supported by lugs 24 on arms 25, which arms 25 are part of flanges I8. The lugs 24 are integral with `Ushaped member 2 3. The arms 25 are formed so that the lugs 24 are supported directly beneath the holes 2| in which are mounted the support pins 20 of toggle T.

The arms of the U-shaped member 23 have contact members 26 mounted thereon. These contact members consist of two pieces of thin sheet metal whose ends are bent outward slightly in a well known manner as shown in Figure 6. The ends of contact member 26 are adapted to spread as they clasp the internal vterminals I4.

The U-shaped member 23 and the contact members 26 mounted thereon extend substantially within the lower cavity I3 of the cup-shaped base B.

A compressed spring 21 is positioned between the base of the U-shaped member 23 and the bifurcated element 22. The spring 21 acts to keep the U-shaped member 23 seated on support arms 25 and to keep bifurcated element 22 in engagement with insert I9. When the bifurcated element 22 is swung to an over center position the spring 21 forces the U-shaped member 23 to be pivoted on its lugs 24 to another position. There are two positions which the member 23 can assume, the rst is bridging the gap between the terminals I4 by contact between contact members 26 and terminals I4 and the second is the nonconducting position when the gap between terminals I4 is re-established. y

Figure 3 shows the switch in the iirst or on position and Figure 2 shows the switch in the second or off position.

In modifying this single break switch to a double break switch, I mount a pair of

contact arms

28 and 30 on shoulders Il within the upper cavity I2 of the cup-shaped base B. One contact arm 28 extends across the path of travel of a portion of the edge 29 of the toggle lever T. The other contact arm 30 is positioned out of the path of travel of toggle lever T as clearly shown in Figure 4. Silver contact points II and :la are provided respectively on

contact arms

28 and 30 because there is no wiping action between the contact arms and good electrical contact is desirable.

The

contact arms

28 and 30 are normally urged toward each other so that good electrical contact is made. In the preferred form shown, contact arm 28 has suiicient resiliency to provide the urging force needed to make good contact with arm 30. When the toggle lever T is moved to the off position, the edge 29 of toggle T engages arm 28 and depresses that arm thus breaking the contact between contact points 2| and Sla. When the toggle T is moved to the "on position 4 the arm 28 moves upwardly by reason of its resiliency and contact between Points II and lla is reestablished.

Contact arms 2l and I0 are -secured to external terminal strips 22 by means of screws Il. The external terminal strips 32 are provided with terminal screws 34.

When the switch is moved from the of!" position to the "on position, the toggle T is pivoted about pins 20. As toggle T pivots about pins 20 the edge 2! of the toggle T moves outwardly from upper cavity I2 and contact arm 2l moves upwardly until contact points 3i and IIa meet. This contact between points II and IIa is made before the toggle T passes through the center position. As the toggle T passes through the center position, the spring 21 .moves the U-shaped member 2l so' that contact members 2l engage internal terminals I4. Thus, any arcing that takes place will be between members 2l and internal terminals I4.

Similarly when the toggle T is moved from the on position to the "ofl position, the contact between members 2B and terminals I4 will be broken before the edge 2l of the toggle moves suiilciently into the upper cavity I2 to deflect contact arm 28. Here, too, arcing will take place only between members 25 and terminals I4.

By reference to Figure 5 it will be noted that the terminal screws I1 are connected in one side of the circuit indicated by the wires a and b, while theA terminal screws 24 are connected in the other side of the circuit indicated by the wires c and d. The load is indicated as a heating element Il such as that found in an electric stove.

Thus, it can be seen that there has y'been provided a simple and novel mechanism whereby an inexpensive and relatively small' single break switch may be modified into a more expensive double break switch without the necessity of increasing the size of the switch.

While there has been shown and described a particular embodiment of this invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the invention and, therefore, it is intended in the appended claims to cover all such changes and modications as iall within the true spirit and scope of the invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. In a switch comprising a cup-shaped `base of insulating material having internal mounting shoulders forming substantially a lower cavity and an upper cavity therein, a manually actuated toggle member pivoted in said upper cavity.

,ona pivot support mounted on a portion of the internal shoulders, a pair of spaced terminals mounted on said internal shoulders and extending downward into the lower cavity, said terminals adapted to be interposed in one side of an electric circuit, and engaging means operatively associated with said toggle member extending within said lower cavity and having portions thereof adapted to be selectively engaged and disengaged with said terminals; the improvement and modification of said switch comprising a pair of contactors mounted within said upper cavity upon said mounting shoulders and adapted to be interposed in the other side of said electric circuit, said contactors being resiliently urged into electrical conducting contact with each other, one o! said contactors having a portion thereof positioned across lthe arc of swing o! the pivoted toggle member, and-said toggle member adapted to engage sai-d portion of said one contactor to separate said pair of contactors.

2. A switch as set forth in claim 1 wherein the means for engaging and disengaging said pair of spaced terminals extending within said lower cavity includes a spring pressed snap acting contactor. whereby the making and breaking of circuits in which said terminals and contactors are interposed is done in sequential order, said terminals .being rst disengaged and said contactors then being separated when the manually actuated toggle member is swung in one direction,

67 and the contactors rst contacting and then the terminals being engaged when said toggle member is swung in the opposite direction.

ALFRED J. HUCK.

References Cited in the le of this patent UNITED STATES PATENTS Number Name Date 1 1,959,205 Hanel May 15, 1934 2,073,529 Sam'bleson Mar. 9, 1937 2,190,342 Smith Feb. 13, 1940