WO1987004561A1

WO1987004561A1 - Unitary switch and circuit breaker

Info

Publication number: WO1987004561A1
Application number: PCT/US1986/000087
Authority: WO
Inventors: Thomas S. Slater; Wade R. Bowden; Emma Levin
Original assignee: Slater Electric, Inc.
Priority date: 1986-01-23
Filing date: 1986-01-23
Publication date: 1987-07-30
Also published as: EP0253807A1

Abstract

A unitary switch and circuit breaker (10) includes first and second contacts (28, 30), a switch circuit including a pivotally mounted rocker arm (14) for actuating the first and second contacts (28, 30) to assume a first condition (Fig. 4) in which the contacts (28, 30) are open and a second condition (Fig. 5) in which the contacts (28, 30) are closed, the rocker arm (14) traveling in an arc to actuate the first and second contacts (28, 30) to assume the first and second conditions, and a breaker circuit (24, 26, 32, 42, 56, 57) for actuating the first and second contacts (28, 30) to interrupt current flow therethrough in response to the current flow exceeding a predetermined level, the breaker circuit (24, 26, 32, 42, 56, 57) including a non-conducting portion (38) for interposing between the first and second contacts (28, 30) to subsequently prevent resumption of current flow until reset, and a reset element (32) including a guide (36, 36a, 36b) dimensioned to be constrained in the groove (68, 68a, 68b) in the rocker arm (14), and a flexible portion (100) for flexibly connecting the guide (36, 36a, 36b) and the non-conducting portion (38) whereby the guide follows the arc of travel of the rocker arm (14).

Description

UNITARY SWITCH AND CIRCUIT BREAKER

BACKGROUND OF THE INVENTION This invention relates to electrical switches and circuit breakers, and more particularly, to a combination switch and circuit breaker.

° BACKGROUND ART

Circuit breakers are used in a wide variety of electronic systems in which components must be protected from large currents such as those that accompany circuit malfunctions or external power ■5 surges. A circuit breaker is connected between the source of power and the components to be protected, and contains a component that trips when excessive current flows through it, opening the circuit through the circuit breaker and disconnecting the source of 0 power from the components to be protected. Electronic systems frequently include on and off switches connected in series with the circuit breaker for turning on or off the electronic system. Frequently, separate switches and circuit breakers *5 are used ^'in electronic systems. Since two units are used, a relatively large amount of space is required to accommodate both units.

A combined switch and circuit breaker unit is disclosed in U.S. Patent No. 4,528,538 to 0 Andersen. This is a single unit and it operates so that after interruption of the current flow by the circuit breaker, opening the switch circuit resets the circuit breaker. In Andersen, however, the switch and circuit breaker are electrically separate units and are not unitary. The Andersen device is not very compact since the switch and circuit breaker are electrically separate units. The Andersen device is also relatively expensive to manufacture since it is relatively complex, and comprises numerous parts. - DISCLOSURE OF THE INVENTION

It is thus an object of the present invention to overcome the aforesaid defects of the prior art.

It is also an object of the present •5 invention to provide a unitary switch and circuit breaker that reduces the number of components used to perform both the switching function and the circuit breaker function.

It is still a further object of the present ® invention to provide a unitary switch and circuit breaker in which the two functions are performed in a single unit.

It is yet another object of the present invention to. provide a unitary switch and circuit **-- breaker that is small in size and. relatively compact.

It is still a---further object of the present invention to provide a unitary switch and circuit breaker that indicates when the circuit breaker function has been actuated. 0 It is yet a further object of the present invention to provide a unitary switch and circuit breaker in which activation of the circuit breaker function places the switch function in the off position.

It is yet a further object of the present invention to provide a unitary switch and circuit breaker that permits easy reset of the circuit breaker function.

It is still another object of the present invention to provide a unitary switch and circuit breaker that permits the circuit breaker function to be reset, once tripped, by one actuation of the switch function.

It is another object of the present invention to provide a unitary switch and circuit breaker that permits the circuit breaker function to be reset, once tripped, by a single movement of the switch.

It is yet another object of the present invention to provide a unitary switch and circuit

10 breaker which turns off the switch function when the circuit breaker function is actuated.

It is an even further object of the present invention to provide a unitary switch and circuit breaker in which placing the switch in the "on" ⁱ⁵⁾ condition simultaneously resets the circuit breaker function.

In accord with -the present invention, a unitary switch and circuit breaker includes switching means with a pivotally mounted rocker arm means, with

20 a groove therein, for actuating the first and second contact means to assume a first condition in which the contact means are open and a second condition in which the contact means are closed, the rocker arms means traveling in an arc to actuate the first and 5 second contact means to assume the first and second conditions, and breaker means for actuating the first and second contact means to interrupt current flow therethrough in response to the current flow exceeding a predetermined level, the breaker means 0 including non-conducting means for interposing between the first and second contact means to subsequently prevent resumption of current flow until reset, and reset means for displacing the non-conducting portion from between the first and second contact means to reset the breaker means after the breaker means interrupts the current flow, the reset means including guide means dimensioned to be constrained in the groove in the rocker arm means, and flexible means for flexibly connecting the guide means and the non-conducting means whereby the guide means follows the arc of travel of the rocker arm means.

As preferably embodied, one set of electrical contacts are operated by both the switch means and the breaker means. The above, and other objects, features and advantages of the present invention will be apparent ^; from the following detailed description of illustrative embodiments thereof which is to be read in connection with accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a perspective view of an embodiment of a unitary switch and circuit breaker in accord with the present invention;

Fig. 2 is an exploded, perspective view illustrating the component parts of the embodiment of Fig. 1;

Fig. 3 is a plan view of a terminal lug of the embodiment of Fig. 1 illustrating a thermally sensitive bimetallic strip;

Fig. 4 is a cutaway plan view of the reverse side of the embodiment of Fig. 1 showing the contacts in the open condition;

Fig. 5 is a cutaway plan view of the reverse side of the embodiment of Fig. 1 showing the_-Contacts in the closed condition;

Fig. 6 is a side view~of the embodiment of Fig. 1 showing the switch function in the off condition and the circuit breaker function in the open condition;

Fig. 7 is a side view of the embodiment of Fig. 1 illustrating the switch function in the on condition and the circuit breaker function in the closed condition;

Fig. 8 is a side view of the embodiment of Fig. 1 illustrating the switch function in the on condition and the circuit breaker function in the open condition;

Fig. 9 is a view taken along- the line 9-9 of Fig. 1;

Fig. 10 is a cutaway side view of an alternate embodiment of the present invention.

Fig. 11 is a partial, plan view of a rocker arm and tab in an embodiment of the present invention;

Fig. 12 is a partial, perspective view of the tab of Fig. 11;

Fig. 13 is a partial, plan view of another rocker arm and tab in an embodiment of the present invention;

Fig. 14 is a partial, perspective view of the tab of Fig. 13;

Fig. 15 is a side view of a reset element in accord with another embodiment of the present invention;

Fig. 16 is a perspective view of the reset element of Fig. 15; and

Fig. 17 is a cutaway side view of an embodiment of the present invention.

DETAILED DESCRIPTION Referring to the drawings, and initially to Figs. 1 through 3 thereof, an embodiment of a unitary switch and circuit breaker 10 is disclosed. Device 10 includes a housing 12 for containing the electrical contacts and other elements of the device, as more fully discussed hereinbelow. A rocker arm 14 is pivotally mounted on pivot 16 in housing 12. As will be apparent from the following description, device 10 has at least two functions: a switching ' function and a circuit breaker function. When only the switching function of device 10 is utilized, and ignoring the circuit breaker function of device 10, rocker arm 14 pivots between an "on" and an "off" position in which electricity flows or does not flow, respectively, through device 10. When the circuit breaker function is utilized, device 10 can assume a circuit "open" or a circuit "dO-sed" condition in which electricity does not flow or does flow, respectively, through device 10. The two functions ' are integral to device 10, and the parts or elements of the illustrated embodiments cooperate to perform the described functions.

A facing 18 surrounds rocker arm 14 and provides a portion of the mounting structure for - device 10. A pair of retaining arms 20 extend from the lateral edges of housing 12 for elastically cooperating with a mounting surface to retain device 10 therein. For example, device 10 might be inserted through an opening formed in a flat plate or the like (not shown) , with retaining arms 20 flexed to retain ° device 10 in the opening.

Referring to Fig. 2, device 10 includes an upper terminal lug 22, and a pair of lower terminal lugs 24, 26. As is evident to those of skill in the art, lugs 22, 24, 26 provide electrical connections for device 10. Lower lugs 24, 26 have associated therewith first and second electrical contacts 28, 30, respectively. As discussed more fully hereinbelow, first and second contacts 28, 30 provide electrical switching contacts for the switching function of device 10. A reset element 32 is provided for resetting the circuit breaker function of device 10. Reset element 32 has as an integral part thereof a projecting arm 34 with a tab 36 formed on the end. • Reset element 32 also includes a non-conducting area or portion 38 that blocks the flow of current betw_"enreontacts 28, 30, as will be discussed more fully hereinbelow. Reset element 32 also includes a toothed-portion 40 for cooperating with a spring 42. Spring 42 cooperates with a back wall of device 10 to bias reset element 32 to block the flow of current between contacts 28, 30. Apertures (not shown) are formed in the back wall so that lugs 22, 24 and 26 can project therefrom in the form of male contact blades. The back wall includes a projecting portion 44 to receive spring 42 and reset element 32. Lug 22 provides an electrical connection for a pilot lamp 48. Lamp 48 is positioned in a cradle 46 that fits within rocker arm 14. In the preferred embodiment, rocker arm 14 is made of a transparent or translucent material, such as plastic, whereby lamp 48 is visible. Also in the preferred embodiment, lamp 48 is illuminated when rocker arm 14 is placed in the switch "on" condition, and is not illuminated when rocker arm 14 is placed in the switch "off" condition, or if the circuit breaker function has been actuated (even if rocker arm 14 is in the "on" condition) .

Fig. 3 illustrates a bimetallic strip 56 associated with lug 26. Bimetallic strip 56 is a thermally sensitive bimetallic strip with a tongue 57

^•^ coupled to lug 26 for mounting contact 30. Such a bimetallic strip can be, for example, a so-called Taylor-type bimetallic strip such as disclosed in U.S. Patent No. 4,379,278 to Kuczynski et al. Strip 56 is made of a flexible, spring-like material in

-*--' which a U-shaped cut-out is made from tongue 57 which — carries contact 30. As is evident to those with skill in the art, when an overload occurs, strip 56 heats up until tongue 57 snaps back to buckle over the switch center resulting in an instantaneous 0 displacement of the tongue 57 to separate contact 28 on lug 24 from contact 30 on tongue 57.

Fig. 4 illustrates an embodiment of the device of the present invention in which rocker arm 14 has been pivoted so that contacts 28, 30 are in 5 the open condition. Referring briefly to Fig. 2, rocker arm 14 includes an actuating arm 58 projecting therefrom. Arm 58 projects through a hole or an aperture in cradel 48 to engage bimetallic strip 56. The pivotal action of rocker arm 14 causes bimetallic 0 strip 56 to move rightward in the illustrated - 11 -

" embodiment to open contacts 28, 30.

In the embodiment of Fig. 4, lug 24 is positioned in slots or grooves 60, 62 formed in housing 12. Lug 22 is disposed in a groove or slot 64 in housing 12. Lug 26 is disposed in a groove or 5 slot 66 in housing 12.

In Fig. 5, reset element 32 is not positioned between contacts 28, 30, as rocker arm 14 is placed in the "on" condition.

The operation of the circuit breaker feature 0 of the illustrated embodiment is next to be described.

When a current surge occurs, and the current supplied to device 10 exceeds a predetermined threshold, bimetallic strip 56 is actuated to separate contacts 28, 30. When the surge occurs, 5 tongue 57 bends enough to buckle over and move contact 30 to the right from the position seen-irr^*"^-' Fig. 5, whereby non-conducting portion 38 of reset element 32 is urged into a blocking position between contacts 28, 30 by the biasing action of spring 42. 0 Assuming that the external power surge is no longer present, displacement of reset element 32 will displace non-conducting portion 38 from a position between contacts 28, 30 whereby current can again flow through contacts 28, 30. Non-conducting portion 5 38 is returned to its abutting position with contact 30.

The operation of the switching feature of device 10 is next to be described.

As illustrated in Fig. 4, when rocker arm 14 0 is placed in the "off" condition, projecting arm 58 engages tongue 57 and laterally displaces it to the right. The lateral displacement of tongue 57 separates contacts 28, 30, thus breaking the flow of current therethrough. Spring 42 biases non-con¬ ducting portion 38 of reset element 32 between contacts 28, 30.

Pivotal.movement of rocker arm 14 to the "on" condition causes projecting arm 58 to disengage from tongue 57. At this point, non-conducting portion 38 of reset element 32 is still between contacts 28, 30. Tab 36 must next be depressed to displace non-conducting portion 38 from between contacts 28, 30. Tongue 57 then bends over whereby contacts 28, 30 meet. Fig. 5 illustrates device 10 with rocker arm 14 (not shown), and hence- device 10, in the "on" condition. In Fig. 5, reset--eiement 32 has been omitted for

Figs. 6 through 9 illustrate the indicator- function of an embodiment of the present invention wherein tab 36 extends outwardly from housing 12 through a slot or groove 68 formed on a lateral edge of rocker arm 14. As illustrated most clearly in Fig. 8, when the circuit breaker function of the device 10 has been actuated, and contacts 28, 30 are in the open position, so that no current flows through device 10, tab 36 extends beyond housing 12 visually to indicate that the circuit breaker function of the device is in the "open" condition. In Fig. 6, the switching function of device 10 is in the "off" condition, that is, contacts 28, 30 are separated by a gap or space so that no current can flow therethrough.

In Fig. 7, tab 36 does not extend from housing 12 since the circuit breaker function is in the "closed" condition. Rocker arm 14 of device 10 is in the "on" condition.

In Fig. 8, the circuit breaker function is in the "open" condition, but rocker arm 14 is in the "on" condition. In the illustrated embodiment, tab 36 extends beyond housing 12, visually indicating that the circuit breaker function of device 10 has

10 been actuated and contacts 28, 30 are open. It is to be noted that in the embodiment of Fig. 8, contacts 28, 30 are open, even though rocker arm 14 is in an "on" condition, whereby contacts 28, 30 would otherwise be- closed. In the illustrated embodiment, ^***-' non-conducting portion 38 of reset element 32 is disposed between contacts 28, 30, effectively preventing the flow of current therethrough.

Fig. 9 illustrates slot or groove 68 in rocker arm 14 through which tab 36 projects from

20 housing 12.

Fig. 10 illustrates an alternate embodiment of the present invention in which tab 36 is not included as a portion of reset element 32. Rather, projecting arm 34 of reset element 32 engages the 5 lower edge of rocker arm 14. In the illustrated embodiment, when the circuit breaker function of device 10 has been tripped, and is in the "open" condition, displacement of reset element 32 will pivot rocker arm 14 into the "off" position. 0 Conversely, pivotal movement of rocker arm 14 will displace reset element 32 and non-conducting portion 38 from its blocking position between contacts 28, 30. Thus, turning "on" device 10 automatically resets the circuit breaker function of the device. Conversely, operation of the circuit breaker function of device 10 provides a visual indication of such actuation because rocker arm 14 is moved to the "off" position. However, it is to be noted that, in the embodiment of Fig. 10, an operator cannot determine whether device 10 is in the "off" position because

10 the circuit breaker .function of the device has been actuated, or because the device 10 has simply been placed in the "off" position.

In the embodiment of Figs. 1 through 9, tab 36 has a substantially rectangular cross-section that *- cooperates with a similarly shaped groove 68..in- rocker arm 14. Other cross-sectional shapes of tab 36 are possible. For example, as illustrated in Figs. 11 and 12, tab 36a can have a straight dove-tail shape. Dove-tail tab 36a of Figs. 11 and

20 12 comprises a substantially rectangular-shaped central portion 70 with shoulder-shaped portions 72, 74 extending laterally therefrom. In tab 36a of Figs. 11 and 12, substantially rectangular shoulder portions 72, 74, along with substantially rectangular 5 central portion 70, are dimensioned to give tab 36a a substantially "flattened" appearance.

Figs. 13 and 14 illustrate a tab 36b with an angular dove-tail shape. Tab 36b cooperates with a similarly shaped groove 68b in rocker arm 14. As 0 illustrated most clearly in Fig. 14, tab 36b has an upper flat surface 76, a lower, flat, plane surface 78, and two slanted faces 80, 82. In tab 36b, faces 76, 78 are substantially larger than faces 80, 82, thus giving tab 36b a "flattened" shape.

It is to be appreciated that, with tabs 36a, 36b configured as in Figs. 11 through. 14, tabs 36a,

36b are held more securely in slots 68a, 68b, than is the case in the embodiment of Figs. 1 through 9.. More particularly, tab 36 is free to be displaced from slot 68 (see Fig. 9) while tabs 36a, 36b are constrained within slots 68a, 68b due to the shape of tabs 36a, 36b and the cooperating shapes of slots 68a, 68b. Thus, tabs 36a, 36b follow the arc of travel of rocker arm 14 when switch 10 is placed in the switch "off" condition. This assures a one-motion reset of the circuit-breaker function when rocker arm 14 is. plac d in the "-on" condition.

In the embodiment of Figs. 11 through 14, reset element 32 is made of sufficiently flexible plastic material or the like so that tabs 36a, 36b, follow the arc of travel of rocker arm 14 when switch 10 is placed in the switch "off" condition.

Figs. 15 and 16 illustrate an alternative embodiment of reset element 32 that includes a thinned portion 100 of projecting arm 34. Thinned portion 100 flexibly connects tab 36 with toothed-portion 40 and non-conducting portion 38, so that projecting arm 34 is flexible. Hence, tab 36a follows the arc of travel of rocker arm 14 when switch 10 is placed in the switch "off" condition. In the illustrated embodiment, the tab has the ° straight dove-tail shape of Figs. 11 and 12 and is indicated by reference numeral 36a. Other shapes of the tab will be suggested to those of ordinary skill in the art, for example, the tab can be of the shape of tab 36b in Figs. 13 and 14. Reset element 32 can be made of a plastic material such as of nylon or polyester.

Fig. 17 illustrates an embodiment of the present invention with reset element 32 of Figs. 15 and 16. In device 10, rocker arm 14 has been placed - in the "off" position, in which tab 36a has followed the arc of travel of rocker arm 14. As explained in connection with Figs. 15 and 16, tab 36a is constrained in slot 68a. Thinned portion 100 of reset element 32 has flexed to permit tab 36a to follow rocker arm 14.

It is to be appreciated from the above description of the preferred embodiments that a unitary switch and circuit breaker in accord with the present invention is particularly compact, especially because only a single pair of contacts are included therein and are used for both the switching function and the circuit breaker function.

Although illustrative embodiments of the present invention have been described in detail herein with reference to the accompanying drawings, it is to be understood that the invention is not limited to those precise embodiments, and that various changes and modifications may be effected therein by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.

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Claims

1. A device comprising: first and second contact means; switching means including pivotally mounted rocker arm means, having a groove formed ^*-^** therein, for actuating said first and second contact means to assume a first condition in which said contact means are open and a second condition in which said contact means are closed, said rocker arm means traveling in an arc to actuate said first and

^•*-" second contact means to assume said first and second conditions; and breaker means for actuating said first and second contact means to interrupt current flow therethrough* in response to said current flow

^•*^■•-' exceeding a predetermined level, saicLbr_.e_i.er means including non-conducting--m-e^*an__r^*for interposing between said first and second contact means to ... subsequently prevent resumption of current flow until reset, and reset means for displacing said 0 non-conducting means from between said first and second contact means to reset said breaker means after said breaker means interrupts said current flow, said reset means including guide means dimensioned to be constrained in said groove in said 5 rocker arm means, and flexible means for flexibly connecting said guide means and said non-conducting means whereby said guide means follows said arc of travel of said rocker arm means..

2. The device of claim 1; wherein said flexible 0 means includes a rectangular portion having a thin ° cross-section dimensioned to be flexible.

3. The device of claim 2; wherein said reset means and said non-conducting means comprise a unitary element.

4. The device of claim 3; wherein said guide means includes a tab portion.

5. The device of claim 4; wherein said reset means includes a flattened rectangular portion having a rectangular cross-section positioned adjacent each side of said flexible means.

6. The device of claim 5: wherein said reset means includes bias means for normally biasing said non-conducting portion between said first and second contact means.

7. The device of claim 6; wherein said bias means includes a spring, and means for engaging said spring.

8. The device of claim 7; wherein said means for engaging comprises a plurality of teeth projecting from said reset means.

9. The device of claim 1; wherein said guide means has a polygonal cross-section, and said groove has a corresponding cross-section to receive said guide means.

10. The device of claim 1; wherein said guide means has a rectangular cross-section, and said groove has a corresponding cross-section to receive said guide means.

11. The device of claim 1; wherein said guide means has a dove-tail shape, and said groove is correspondingly dimensioned to receive said guide means.

12. The device of claim 1; wherein said guide means has an angular dove-tail shape, and said groove is correspondingly dimensioned to receive said guide means.

13. The device of claim 1; wherein said reset means includes indicating means for indicating when said breaker means has been actuated.

14. The device of claim 13; wherein said indicating means is coupled to said reset means; and

10 wherein actuation of said indicating means actuates said reset means.

15. The device of claim 14; wherein said indicating means includes a tab.

16. The- device of claim 15; and further

^•*--* comprising housing means for containing said -contact means, said switching means, said breaker means., and - said reset means, said housing means-dimensioned to be compact.

17. The device of claim 16; wherein said tab 0 projects beyond said housing means to visually indicate that said breaker means has been actuated.

18. The device of claim 17; and further comprising means for pivotally mounting said rocker arm means in said housing means. 5-

19. A unitary switch and circuit breaker for use with an electric current comprising: first and second contact means; switching means including pivotally mounted rocker arm means for actuating said first and 0 second contact means to assume a first condition in which said contact means are open and a second condition in which said contact means are closed, said rocker arm means traveling in an arc to assume said first and second conditions, and having a groove formed therein; and breaker means for actuating said first and second contact means to interrupt current flow therethrough in response to said current flow exceeding a predetermined level, said breaker means including an element having a non-conducting portion for interposing between said first and second contact means to subsequently prevent current flow until reset, a reset tab portion dimensioned to be constrained in said groove in said rocker arm means for displacing said non-conducting portion from between said first and second contact means to reset said breaker means and permit current flow through said first and second contact means,- and a thin, flexible portion joining said reset tab portion and said non-conducting portion for transmitting motion from said reset tab portion to said non-conducting portion and for flexing whereby said reset tab portion follows said arc of travel of said rocker arm means.

20. The unitary switch and circuit breaker of claim 19; wherein said breaker means includes biasing means for normally biasing said non-conducting portion of said element between said first and second contact means.