US3486150A - Circuit breaker - Google Patents

Description

Dec. 23, 1969 Filed Sept. 14, 1967 D. E. lCLARKE CIRCUIT BREAKER 7 Sheets-Sheet l v5/QM, wie

Inventor, az/d E'. Clarke,

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Attfy.

Dec. 23, 1969 E CLARKE 3,486,150

C IRCUIT BREAKER Inventor', Baz/d E. Clarke,

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In ven tor,

David E Clarke,

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Dec. 23, 1969 D, E, CLARKE l 3,486,150

CIRCUIT BREAKER Filed Sept. 14, 1967 7 Sheets-Sheet 4 @9.11. 1 Ff'gd- /2 52 `52\ I ||I [lll] 6 6 44 8 y." w @a j y W49 /4 4g t /4 "60ml 36 22 22 Z @2 za@ 69 22 3 H2 2 4 236 72 /26 H2 fyi?.

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Dec. 23, 1969 D, E CLARKE 3,486,150

CIRCUI T BREAKER Filed Sept. 14, 1967 7 Sheets-Sheet 5 AL- /40 L ,40 /40 U0 In vento; /40 30 David E'. CZde,

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Dec. 23, 1969 D. E. CLARKE 3,486,150

C IRCUIT BREAKER Filed Sept. 14, 1967 '7 Sheets-Sheet 6 Inventor, Daz/id E. C'Zarie, y QQWRMMM Atthy.

I De@ 23, 1969 D'. E CLARKE 3,486,150

C IRCUI T BREAKER Filed Sept. 14, 1967 '7 Sheets-Sheet 7 5J @M @we um United States Patent U.S. Cl. 337-43 4 Claims ABSTRACT OF THE DISCLOSURE A miniature, trip-free, ambient-compensated multipole circuit breaker has a plurality of compartments in each of which a bell crank latch is normally engaged with an ambient-compensated catch for holding tixed and movable contacts engaged to close a circuit. The bell crank latches are mounted for individual rotation on a common shaft, and, in each compartment, current-responsive means are adapted to release the catch from the bell crank to open the respective compartment circuit in response to overload current in the circuit. A plurality of cam means is adapted to be rotated when a catch is released from a bell crank in response to overload current in any one of the compartment circuits. Pairs of the cam means are interconnected for common rotation so that rotation of any cam means upon opening of any compartment circuit rotates other cam means to release catch engagement with the bell cranks in other compartments for opening the other compartment circuits. A single manual actuating member is connected to the shaft to permit simultaneous manual opening of all of the compartment circuits.

tions, the multipole circuit breaker device should be manually operable as a switching device, should be easily calibrated for automatic operation in response to selected overload current and should be ambient-compensated. The device should also be trip-free so that, when the device has opened a plurality of circuits in response to an overload current in one of the circuits, none of the circuits can be reclosed while the currentresponsive means in said one circuit remains conditioned by the overload current. It is also important that such multipole circuit breakers be of small size relative to their current-carrying capacity.

In a manually and automatically operable, trip-free, ambient-compensated single pole circuit breaker described in the present inventors copending application for patent, Ser. No. 504,632 filed Oct. 24, 1965, now Patent 3,361,882, the disclosure of which is incorporated herein by this reference, novel structural features are "ice utilized to achieve a device of wide capability in a construction of exceedingly small size. While this earlier single pole device has constituted a considerable advance in the art of miniaturization of circuit breakers, three-phase and other multipole circuit breakers of corresponding current capacity and operating characteristics previously known in the art have been of signicantly less compact construction and frequently have occupied a volume twenty times or more greater than the volume of the described miniature single pole circuit breaker.

It is an object of this invention to provide a new and improved snap-acting multipole circuit breaker for the protection of electrical circuit components against transients, sustained overload, and short circuits; to provide a circuit breaker of the class described which is fully trip-free; to provide a thermostatic multipole circuit breaker which is ambient compensated; to provide such a circuit breaker which is easily calibrated and adjusted for automatic operation; to provide such a multipole circuit breaker which operates in response to current conditions in a single circuit without -being affected by current conditions in related circuits; to provide such a circuit breaker which automatically opens all phases of a polyphase circuit in response to transient 0r sustained overload current in any phase circuit; to provide such a multipole circuit breaker which indicates when the circuit breaker has automatically tripped; to provide such a circuit breaker which can be used as a manually operated switch without deleterious eects on its function of responding properly to overload currents; to provide such a circuit breaker which is economical to manufacture and is readily adapted to mass production; and especially to provide such a multipole circuit breaker which is of small size, light weight, and exceedingly compact construction.

Other objects and advantages of the novel and improved multipole circuit breaker of this invention appear in the following detailed description of a preferred embodiment of the invention, the detailed description referring to the drawings in which:

FIG. 1 is a vertical section View of the multiple circuit breaker of this invention along the vertical axis of the circuit breaker;

FIG. 2 is a section view along lines 2 2 of FIG. l;

FIG. 3 is a section view along lines 3 3 of FIG. 1;

FIG. 4 is a section view along lines 4 4 of FIG. l;

FIG. 5 is an enlarged partial view, partially sectioned, similar to FIG. l;

FIG. 6 is a section view along line 6 6 of FIG. l;

FIG. 7 is a perspective View 0f a cam member incorporated in the circuit breaker of FIG. l;

FIG. 8 is a section view along line 8 8 of FIG. l;

FIG. 9 is a perspective view of an arc shield incorporated in the circuit breaker of FIG. l;

FIG. 10 is a section view similar to FIG. 4 illustrating the position of the circuit breaker parts in manuallyopened circuit breaker position;

FIG. 11 is a section view similar to FIG. 4 illustrating the position of parts of the circuit breaker immediately upon opening of the circuit breaker contacts in response to overload current;

FIG. 12 is a partial section view along line 12 12 of FIG. 11;

FIG. 13 is a partial section View along line 13-13 of FIG. 11;

FIG. 14 is a front elevation view of a catch means incorporated in each of three compartments of the circuit breaker of FIG. 1;

FIG. 15 is a section view along line 15-15 of FIG. 14;

FIG. 16 is a partial perspective view of the circuit breaker of FIG. l illustrating cooperation of cam means in the separate compartments of the circuit breaker for opening all circuit breaker circuits in response to overload current in one of the breaker circuits;

FIG. 17 is a side elevation view of a fixed contact incorporated in the circuit breaker of FIG. l;

FIG. 18 is a front elevation view of the contact shown in FIG. 17;

FIG. 19 is a plan view of a combined mounting an adjusting bracket incorporated in the circuit breaker of FIG. l;

FIG. 20 is a side elevation view of the bracket of FIG. 19;

FIG. 21 is a section view along line 21-21 of FIG. 19;

FIG. 22 is a side elevation view of an assembly of the bracket of FIG. 19 with other components incorporated in the circuit breaker of FIG. l;

FIG. 23 is a front elevation view of the assembly shown in FIG. 22;

FIG. 24 is a partial section view along line 24-24 of FIG. 23;

FIG. '25 is a front elevation view of a spring incorporated in the device of FIG. 1;

FIG. 26 is a side elevation view of the spring shown in FIG.

FIG. 27 is a perspective view of a 'bell crank member incorporated lin the circuit breaker of FIG. l; and

FIG. 28 is a diagrammatic view illustrating assembling of the spring shown in FIG. 26 with the bell crank member shown in FIG. 27.

Referring now to the drawings, and more particularly to FIGS. I and 3, one embodiment of this invention takes the form of a thermostatic three-phase circuit breaker generally indicated by reference numeral 10 and includes a base housing or casing which may be made of any suitably strong, insulating and arc-resistant material such as ceramic material, molded phenolic resin, or the like. For ease of assembly of the circuit breaker into a complete device, the casing is preferably made of clam- shells 12, 14, 16 and 18 and two insulating spacers 20. In this construction as shown in FIG. 1, six clam-shell units of the four different clamashell constructions are arranged in pairs separated by the spacers 20 and are held together by studs 22 and nuts 24 to form three, circuit- breaker compartments 26, 28 and 30. The clam-shell units when secured together in pairs in the manner -described cooperate in conventional manner in forming slots for receiving the xedly mounted terminal structures 32 and 34 as described in the noted earlier filed application for patent. The terminals are preferably but not necessarily of the screw type as illustrated. The spacers 20 are relatively longer than the clam-shell units as shown for separating the terminal structures 32 and 34 associated with the respective circuit breaker compartments.

Oppositely of the terminal structures 32 and 34, the clam-shell units form molded shoulders 36, these shoulders being received within matching grooves in plugs 4U and in the neck structure 44 for securely mounting the plugs and neck structure on the casing. The neck struc-- ture 44 comprises the mounting for a manual actuating means and a mechanical latch hereinafter described. The neck structure is also externally threaded as shown for use in mounting the circuit breaker 10 upon a control panel or the like as will be understood. In order to keep the neck from turning in the casing, the neck is provided with at portions 46 as shown particularly in FIG. 2, these flat portions cooperating with matching flat portions on the clameshell units to prevent rotation of the neck structure on the casing.

In accordance with this invention the neck 44 is provided With coaxial bores `48 and S0, and a manual actuating means 52 is movably mounted within the neck bores. As shown particularly in FIGS. 4 and 12, the manual actuating means 52 includes a push-button 0r head 54 and a cylindrical metal sleeve 56, the push-button preferably being formed of an electrically-insulating phenolic resin or the like and being attached to the sleeve by means of a screw 58. In a preferred construction the head of the screw 58 is set within a recess 60 in the push-button 54 and a cover 62 is press-fitted into the recess to prevent tampering with the screw. The sleeve 56 is preferably provided with a longitudinal keyway 64 and a key 66, formed by an upsetting operation on the neck 44, its into the keyway to permit axial sliding movement of the actuating means 52 in the neck While preventing rotation of the actuating means in the neck as described in the noted earlier tiled application for patent. The sleeve 56 is provided for a portion of its length with a bore 68, and a latch plunger 70, preferably made of hardened steel, is slidably received in the sleeve bore 68. The middle portion of the latch plunger is fashioned as shown in the form of a pair of coaxial cones Whose apices are joined. In addition, a connecting link 72, preferably formed of a molded, tough, insulat ing material such as phenolic resin or nylon or the like is attached to the latch plunger by any suitable means. A hole 73 is provided through the end of the connecting link and a suitably dimensioned slot 74 is also provided in the connecting link so that the connecting link forms a clevis or yoke. The sleeve 56 slidable in the neck 44 preferably has a smaller diameter portion at one end forming a shoulder 78 to bear against the compression spring 80, the opposite end of the spring 80 bearing against a Washer 82 attached to the neck structure 44 as shown. The sleeve 56 is also provided with two holes 84 and 86 as shown particularly in FIG. 12, each hole being adapted to slidably receive respective ball bearings 88 and 90.

In this construction, the ball bearings 88 and 90 cooperate with the neck structure 44 and with the manual actuating means 52 to form a mechanical latch for releasably securing the manual actuating means in selective position within the neck structure in a manner which will be hereinafter described. As shown, this mechanical latch is substantially completely enclosed within the neck structure 44 utilizing otherwise unused space within the neck portion normally -used for mounting the circuit breaker 10 on a control panel or the like, thereby contributing to the miniaturization of the circuit breaker o this invention.

Referring now in greater detail to the terminals 32 and 34, it can be seen by reference FIGS. 1 and 4 that a terminal 32 and a terminal 34 are mounted in each of the circuit breaker compartments 26, 28 and 30 and are associated with fixed electrical contacts 92 and 94 respectively within each of the circuit breaker compartments. That is, as shown in FIGS. 17 and 18, an electrical clontact 92 is attached by welding or the like to an extension of each terminal 32 so that, when the terminals are held within matching slots in pairs of clam-shell units forming part of the circuit breaker housing, an electrical contact 92 is located in fixed position within each of the circuit breaker compartments.

Similarly, as shown in FIGS. 22-24, an electrical contact 94 is associated with each terminal 34 so that when these terminals are held within matching slots between pairs of clam-shell units in the circuit breaker housing, a contact 94 is located in xed position within each of the circuit breaker compartments. That is, as shown in FIGS. l9-21 a channel member 96 is provided for at* tachment to the terminal 34. One ange '98 of the channel member is provided with a threaded bore 100 and an adjusting screw 102 is threaded into the bore to engage the opposite flange 104 of the channel member. The web of the channel member is apertured at 106, is provided with a weld projection 108, and is slotted at 110, the end portions of the channel member web preferably being bent to lie in a plane above the plane of the central portion of the channel member web as shown particularly in FIG. 20. The channel member, which is preferably formed of metal of high electrical conductivity, then has its central web portion welded or otherwise securely attached in electrically conductive relation to the terminal 34. A thermostatic bimetallic actuator 112, substantialy U-shaped in form, is electrically connected at one end to the channel member 96 and at its opposite end to the electrical contact 94. That is, as shown in FIG. 22, one end of the bimetallic actuator 112 is welded or otherwise secured in electrically conductive relation to the channel member 96 at the location of the weld projection 108. As shown particularly in FIG. 24, a rivet 116 passing through an insulating bushing 118 in the channel member aperture 106 securely attaches the bimetallic actuator 112 to an electrically conductive strap 120 while supporting the strap and the associated end of the bimetallic actuator in electrically insulated relation to the channel member 96. The inner surface of the bimetallic actuator is provided with partial coatings 122 and 123 of plastic material or the like for assuring the desired electrical insulation between channel member 96 and the actuator 112 other than at the location of the weld projection 108. As illustrated in FIGS. 22-24 the connecting strip 120 is welded or -otherwise electrically connected to a rigid electrically conductive support 124 which, in turn, is welded or otherwise electrically connected to the contact 94. In this arrangement, each pair of contacts 92 and 94 is adapted to be bridged by a movable contact means to close an electrical circuit between respective pairs of terminals 32 and 34.

In accordance with this invention, each of the cornpartments 26, 28 and 30 of the circuit breaker 10 also encloses a catch mechanism 126 which is illustrated in detail in FIGS. 14 and l5. As shown, the catch mechanism 126 incorporates a generally U-shaped bimetallic support member 128 and a T-shaped rigid catch blade 130 which is welded or otherwise securely attached to the ends of the support member to dispose an elongated leg 132 of the T-shaped member between the legs of the support member. Flexing of the bimetallic member 128 in response to a change in ambient temperature moves the end 134 of the bimetallic member (to the left as shown in FIG. 15) without corresponding movement of the distal end of the leg 132 of the T-shaped member. A spring member 136 is welded or otherwise attached to one side of the leg 132 as shown in FIGS. 14 and 15, and a bifurcated cam follower plate 138 is welded or otherwise attached to the opposite side of the leg 132. As shown particularly in FIGS. 1 and 4, a catch mechanism is pivotally mounted at one end in each of the circuit breaker compartments 26, 28 and 30 by tting the ends 140 of the T-shaped member 130 in slots 142 molded in the clam-shell units forming the circuit breaker housing. In this arrangement, the spring 136 incorporated in each of the catch mechanisms 126 bears against the wall of the circuit breaker housing as indicated particularly at 144 in FIG. 4 to bias the catch mechanism toward the center of its respective circuit breaker compartment.

In accordance with this invention, the connecting link 72 on the manual actuating means 52 supports a single shaft 146 in the link hole 73, the shaft extending to either side of the link through each of the circuit breaker compartments 26 and 30 as shown particularly in FIGS. 1 and 3. This shaft 146 is provided with insulating sleeves 148 at either side of the connecting link 72. The clam- shell units 12 and 18 are provided with slots 150 and clam- shell units 14 and 16 are provided with slots 152 for permitting limited vertical movement of the shaft 146 in response to movement of the manual actuating means S2. As illustrated particularly in FIG. 8 the casing spacers 20 each have a central aperture 156 which permits such vertical movement of the shaft 146 to occur.

The shaft 146 supports three substantially similar bell crank latch mechanisms 158, and 162 within the circuit breaker compartments 26, 28 and 30 respectively. Mechanism 160, representative of mechanisms 158 and 162, is illustrated in FIG. 27 and is shown to comprise a bell crank having a latch part 164 and an extending leg 166, the leg and latch part being angularly disposed with respect to each other. The bell crank is adapted to resiliently mount the contact leaf spring assembly 168 (see FIGS. 25 and 26) and for this purpose the bell crank is recessed at 170 to form the shoulders 172, 174, 175 and 176. The contact leaf spring assembly 168 preferably includes a leaf spring 78 of beryllium copper or the like formed with a bight portion therein and includes a contact member 182 which is secured at one end of the leaf spring. The Contact member preferably comprises a bilayer material including a layer 184 of electrical contact material such as silver and a backing layer 186 of steel, nickel or the like 'which is easily welded to the leaf spring 178. The leaf spring 178 is provided with an aperture 188 in the bight portion thereof and is provided with an inwardly bent portion 190 by means of which the compact leaf spring assembly is resiliently mounted on the bell crank 160. In this arrangement, as illustrated in FIG. 28, the bight portion of the leaf spring 178 is easily compressed and is fitted into the recess 170 in the bell crank 160. The compression of the leaf spring is then released so that the spring expands to engage the shoulders 172, 174, 175 and 176 on the bell crank for securely holding the contact leaf spring assembly to the bell crank. As shown in FIG. 25, the leaf spring 178 and the contact member 182 are preferably bifurcated as indicated at 192. The bell crank member 160 also includes a central bore 194 adapted to t around the shaft 146 as illustrated in FIGS. 1 and 3 to mount the bell crank 160 and its associated contact leaf spring assembly 168 for free rotation on the shaft. The bell crank 160 also includes an aperture 196 in the extending leg thereof and, as illustrated in FIG. 4, a helical coil tension spring 198 is connected at one end to the aperture 196 and at its opposite end to a pin 199 attached to the wall of the lcircuit breaker housing for biasing the bell crank 160 for rotation (in a counter clockwise direction as viewed in FIG. 4) on the shaft 146.

The latch mechanisms 158 and 162 include comparable bell crank members 200 and 202 which have larger central bores than the bell crank 160 for mounting the bell cranks 200 and 202 for free rotation on the insulating sleeves 148 and 150 on the shaft 146 as will be understood. The bell cranks 200 and 202 preferably have bushings 204 and 206 respectively secured thereto in coaxial relation to the central bores in the bell cranks to assure that the bell cranks do not cut through the insulating sleeves 148 and 150 during rotation of the bell cranks. The latch mechanisms 158 and 162 mount respective contact leaf-spring assemblies 168, are biased for rotation by springs 198, and are otherwise similar to the latch mechanism 160. As illustrated in FIGS. 1 and 3, the latch mechanisms 158, 160 and 162 are located on the shaft 146 so that the latch parts of the bell crank thereof are adapted to fit between the bifurcation of the cam followers 138 to engage the extending legs 132 of catch blades 130 of the respective catch mechanisms 126 in compartments 26, 28 and 30 of the circuit breaker 10 (see FIG. l5).

In accordance with this invention, cam members 208, 210, 212 and 214 are also mounted for free rotation on the shaft 146 adjacent the latch mechanism 158, 160 and 162. One of these cam members 210, representative of the other cam members, is illustrated in greater detail in FIG.

7 and is shown to have a central bore 216 appropriately sized for mounting the cam for rotation on a shaft 146. The cam is proportioned so that that when mounted on the shaft 146 closely adjacent to the latch mechanism 160, a cam surface 218 normally bears against the leaf spring 178 carried by the latch mechanism 160 and another cam surface 220 normally contacts one of the bifurcations of the cam follower 138 on the catch mechanism 126 located in the circuit breaker compartment 28. See FIG. 4. Two connecting rods 222 are welded or otherwise secured to the cam 210 as shown in FIG. 7, these rods eX- tending through slots 224 and 226 in the adjacent clamshell unit 16 in the circuit breaker housing as shown in FIGS. 1 and 3. See also FIG. 6. The cam member 208 located in the circuit breaker compartment 26 is of similar construction to the cam member 210 but has a larger central bore appropriately sized for mounting the cam 208 on the insulating sleeve 148 on the shaft 146 as will be understood. Similar connecting rods 222 are secured to the cam 208 to extend through corresponding slots 228 and 229 in the adjacent clam-Shell unit 14 in the circuit breaker housing. In this arrangement, the pairs of connecting rods 222 on the cams 208 and 210 are connected together by means of insulating coupling sleeves 230 pressfitted thereon so that the cams 208 and 210 are locked together for common rotation on the shaft 146 but are electrically insulated from each other. See FIG. 5. An arc shield 232 is preferably mounted on the connecting rod coupling sleeves 230 within the aperture 156 in the spacer 20 to prevent arcing between the circuit breaker compartments 26 and 28 through the slots 224, 226, 228 and 229. As will be understood, the cams 212 and 214 are similarly proportioned and coupled together by connection rods 222 and sleeves 230 so that cams 212 and 214 are secured together for common rotation on the shaft 146.

In each of the circuit breaker compartments, a slide or motion-transfer means 234, comprising a at sheet of insulating fiber-board or the like having a central opening 236, is slidably mounted in grooves 238 in the clam- shell units 12, 14, 16 and 18 between the distal or free ends of the bimetallic actuators 112 and respective bimetallic members 128 of the catch mechanisms 126. The apertures 236 in the motion-transfer means permit passage of the Amanual actuator 52 through one of the motion-transfer means while permitting limited horizontal sliding movement of that motion-transfer means.

If desired, arc shields 240 can be located between the contacts 92 and 94 in each circuit breaker compartment as described in the noted earlier filed application.

The operation of the circuit breaker will now be described.

The position of the circuit breaker parts shown in FIG. 4 is arrived at by pushing the manual actuating means 52 inwardly of the circuit breaker housing. That is, when the manual actuating means 52 is pressed inwardly of the housing, the latch plunger 70 and connecting link 72 move the main circuit breaker shaft 146 inwardly of the circuit breaker housing so that the latch parts of the latch mechanisms 158, 160 and 162 become engaged with the extending legs 132 of the catch mechanisms 126 located in respective circuit breaker compartments 26, 28 and 30. This action rotates the latch mechanisms 158, 160 and 162 against the bias of the springs 198 so that the contact members 182 carried by the latch mechanisms are engaged in bridging relation between pairs of contacts 92 and 94 in each of the circuit breaker compartments. In this way, a circuit is closed between the terminals 32 and 34 in each of the circuit breaker compartments. For example, as illustrated in FIG. 4, the circuit closed in circuit breaker compartment 28 extends from a terminal 32 through the contact 92, the contact member 182, the contact 94, support 124, connecting strap 120, 'bimetallic actuating member 112, and channel member 96 to the terminal 34. As the manual actuating means 52 is pressed inwardly of the circuit breaker housing, the latch plunger 70 forces the ball bearings 88 and 90 in holes 84 and 86 in the sleeve 56 to engage the shoulder 49 in the neck structure 44 for releasably latching the manual actuating means 52 in the closed-contacts position illustrated in FIG. 4. While the latch mechanisms 158, and 162 are engaged with a catch mechanism 126, the bias of the springs 198 on the latch mechanism urges the shaft 146, and therefore the latch plunger 70, upwardly preventing release of the ball bearing engagement with the shoulder 49 in the neck structure 44, thereby maintaining the manual actuating means 52 in closedcontacts position as described in the noted earlier tiled application.

For simultaneous manual opening of the circuits in each of the -circuit breaker compartments, the manual actuating means 52 is pushed slightly inwardly of the circuit breaker housing for aligning reduced diameter portions of the latch plunger 70 with the 4ball bearings 88 and 90 permitting the ball bearings to move inwardly toward the latch plunger axis to release their engagement with the shoulder 49 in the neck structure 44 and for permitting the manual actuating means to move with snap action to the position shown in FIG. l0 under the bias of the spring 80 and the springs 198. As the manual actu-ating means moves to the position shown in FIG. l0, the latch mechanisms 158, 160 and 162 are sharply rotated on the shaft 146 for disengaging the contact members 182 carried by the latch mechanisms from the xed contacts 92 and 94 in each of the circuit breaker compartments, thereby opening the circuits in each of the circuit breaker compartments. It will be noted that the latch parts of the latch mechanisms 158, 160 and 162 remain in engagement with the catch mechanisms 126 in the respective circuit breaker compartments during manual opening of the circuit breaker in the manner just described. It will also be noted that the cam members 208, 210, 212 and 214 are rotated with the latch mechanisms by reason of engagement of the cams at 218 with the leaf springs 178 carried 'by the latch mechanisms. However, as the latch mechanisms 158, 160 and 162 move upwardly from the center of the circuit breaker housing with the manual actuating means during manual opening of the circuit breaker, the cam members 210, 212 and 214 rotate with the latch mechanisms without moving the catch mechanisms 126 in the circuit breaker compartments. That is, although the cam surface 220 of cam members are in contact with the cam follower plates 138 of the catch mechanisms, rotation of the cams during manual opening does not exert any camming force on the plates 138. Therefore when the manual actuating means are again pressed inwardly of the circuit breaker housing for moving the circuit breaker parts into closed-contacts position, the engagement of the latch mechanisms 158, 160 'and 162 with the catch mechanisms 126 readily rotates the latch mechanisms for returning the circuit breaker parts to the closed-contacts position shown in FIG. 4.

When the circuit breaker parts are in the closed contacts position shown in FIG. 4 and the circuit breaker is subjected to a change in ambient temperature, the bimetallic actuator 112 tends to flex slightly so that the upper or free end of the actuator as viewed in FIG. 4 moves slightly to the left. At the same time the bimetallic member 128 of the catch mechanism 126 also tends to flex in response to the change in ambient temperature moving the upper or free end of the bimetallic member to the left as viewed in FIG. 4 Without moving the catch plate 132 incorporated in the catch mechanism. This simultaneous movement of the bimetallic members 128 and 112 causes the motion transfer means 234 also to move slightly as will be understood. In this way, the circuit breaker 10 is fully compensated for changes in ambient temperature.

However, if the circuit in Iany of the circuit breaker compartments 26, 28 or 30 is subjected to an overload current, the passage of this current through the bimetallic actuator 112 causes heating of the actuator which is independent of any heating of the bimetallic member 128 in a catch mechanism 126. Thus the bimetallic actuator will move to the left as viewed in FIG. 4 moving the motion-transfer means 234 so that the catch mechanism 126 tends to pivot to the left as viewed in FIG. 4. That is, the motion-transfer means bears against the end 134 of the bimetallic member 128 in the catch mech-anism causing the catch mechanism and the catch plate 132 thereof to move to the left. Thus, for example, when the bimetallic actuator 112 has been suiciently heated in response to overload current in the circuit in compartment 28, the catch mechanism 126 in compartment 28 moves suiciently to release its engagement with the latch mechanism 160 in the compartment for permitting the latch mechanism to begin to rotate (in a clockwise direction as viewed in FIG. 4) under bias of the spring 198.

As the latch mechanism 160 is released by the catch mechanism 126 in the circuit breaker compartment 28, and as the latch mechanism begins to rotate in a counterclockwise direction under the bias of a spring 198, the circuit breaker parts are in the position as shown in FIG. ll. That is, the contact member 182 has been disengaged from the contacts 92 and 94 in the circuit breaker compartment 28. At this point it would appear from FIG. 11 that the latch plunger 70 is no longer restrained from downward movement by the latch mechanism 160 so that the latch plunger 70 could move downwardly permitting the latching ball hearings 88 and 90 to disengage from the shoulder 49 in the neck structure 44, thereby permitting the manual actuating means 52 to move outwardly of the circiut breaker housing to open-contacts position under the bias of the spring 80. However, latch mechanisms 158 and 162 would remain engaged With catch mechanism 126 in the respective circuit breaker compartments 26 and 30 and the engagement of these latch mechanisms with their respective catch mechanism would be suicient to prevent the latch plunger 70 from moving downwardly. In accordance with this invention, however, the cam members 210 and 212 located in a circuit breaker compartment 28 closely adjacent the latch mechanism 160 are positioned so that, during the described counter-clockwise rotation of the latch mechanism 160, engagement of the leaf spring 178 carried 4by the latch mechanism with the cam surfaces 218 of the cams 210 and 212 causes the cams 210 and 212 to rotate with the latch mechanism 160. This rotation of these cam members then serves to open the circuits in the adjacent circuit breaker compartments 26 and 30.

That is, as is illustrated particularly in FIG. 16, cam member 210 is locked together with cam member 208 for common rotation therewith by connecting rods 222 and couplings 230. Therefore, rotation of the cam member 210 is accompanied by rotation of the cam member 208, the cam surface 220 of the cam 208 then bearing against one of the bifurcations of the cam follower plate 138 incorporated in the catch mechanism 126 located in circuit breaker compartment 26. In this way, the cam 208 bears against and pivots the catch mechanism 126 in the circuit breaker compartment 26 until the catch plate 132 thereof releases its latching engagement with the latch mechanism 158. Simultaneously, rotation of the cam member 212 with the latch mechanism 160 causes rotation of the cam member 214 to release engagement of the catch mechanism 126 in circuit breaker compartment 30 from the latch mechanism 162. The latch lmechanisms 158 and 162 then rotate in response to the bias of springs 198 attached thereto for opening the circuits in circuit breaker compartments 26 and 30. When all lof the catch mechanisms 158, 160 and 162 are disengaged from their respective catch mechanisms in this manner, the latch plunger 70 is free to move downwardly, permitting the latching balls 88 and 90 to release engagement with the shoulder 49 in the neck structure 44, and the manual actuating means 52 moves sharply to open-contacts position under the bias of the spring 80. In this way, the circuit breaker is adapted to open all circuits in a three-phase circuit upon the occurrence of an overload current in any one of the circuits and, by moving the manual actuating means to open circuit position, gives visual indication that the circuit breaker has been tripped. In this regard, it will be noted that opening of any circuit in the circuit breaker requires rotation of one of the latch mechanisms 158, and 162 and that as these latch mechanisms move at about the same time with movement of the cam members 208, 210, 212 and 214, the occurrence of an overload current in any circuit breaker circuit results in substantially simultaneous opening of all circuit breaker circuits.

It will be noted that the three-phase or multipole circuit breaker 10` of this invention is adapted for trip-free operation. For example, if the bimetallic actuator 112 has moved in response to an overload current in the circuit through circuit breaker compartment 28 resulting in opening of all of the circuit breaker circuits in the manner just described, and if an attempt is made to close the circuit breaker circuits by manually depressing the manual actuating means 52 while the bimetallic actuator 112 in circuit breaker compartment 28 remains conditioned by said overload current, the latch mechanism 160 cannot engage a catch mechanism 126 in compartment 28 so that the latch mechanism 160 cannot be rotated to reclose the circuit in compartment 28. In addition, as the manual actuating means 52 are moved inwardly of the circuit breaker, engagement of the cam surfaces 220 on the cams 208 and 214 with the catch mechanisms 126 in circuit breaker compartments 26 and 30 prevent engagement of the latches 158 and 162 with the catch mechanisms in compartments 26 and 30, thereby preventing closing of circuits through those compartments.

It will also be understood that, if it is desired to change the calibration of the circuit breaker 10 to provide for automatic operation of the circuit breaker in response to different overload currents in the breaker circuits, the adjusting screws 102 can be located for adjusting the response of the bimetallic actuators 112 in each of the circuit breaker compartments. As such calibration is adequately described in the noted earlier tiled, copending application, such calibration is not further described herein and it be understood that calibration is performed in the manner described in said copending application.

It can be seen that, in the multiple circuit breaker of this invention, each of the breaker circuits is adapted to automatically open in response to overload current in the circuit. The response of the circuit breaker to current conditions in said circuit is independent of the currentconditions in any of the other breaker circuits. Yet when one of the breaker circuits opens in response to an overload current therein, the other breaker circuits are also opened automatically'and substantially simultaneously. The circuit breaker is also manually operable for opening and closing breaker circuits without subjecting the current-responsive breaker means to such use as would upset the calibration thereof. The multiple circuit breaker is easily calibrated, is ambient-compensated and is fully trip-free, Further, the circuit breaker is exceedingly compact and rugged even though it has the wide capabilities noted above.

It should be understood although particular embodiments of the circuit breaker of this invention have been described by way of illustration, this invention includes all modications and equivalents thereof falling within the scope of the appended claims.

I claim:

1. A multiple circuit breaker comprising a housing, a plurality of xed contact means on said housing, manual actuating means mounted on said housing for movement between first and second switch positions, a shaft carried by said actuating means for movement therewith between said switch positions, a plurality of latch means .mounted for individual rotation on said shaft, a plurality of movable contacts mounted on respective latch means for engaging and disengaging respective fixed contact means for .making and breaking respective circuits through said contact means, means biasing said latch means for rotation to open circuit position, a plurality of catch means engaging respective latch means for normally 'holding said latch means in closed circuit position against said bias, current responsive means in respective circuits each adapted to release its respective catch means from its respective latch .means in response to a Selected current in its respective circuit, and a plurality of cam means rotatable on said shaft for releasing respective catch means from said latch means, at least one of said cam means being engageable by each latch means during rotation of said latch means in response to said bias, each of said cam means being interconnected with at least another of said cam means for common rotation therewith to release at least a pair of said catch .means in response to occurrence of said selected current in any one of said circuits.

2. A multipole switching device comprising a housing, a plurality of fixed contact means on said housing, manual actuating means mounted on said housing for movement between iirst and second switch positions, a shaft carried by said actuating means for movement therewith between said switch positions, a plurality of first latch means rotatably mounted on said shaft, movable contact means mounted on respective latch means, a plurality of catch means engageable with respective latch means during movement of said actuating means to said second switch position for rotating said latch means to engage said movable contact means with respective iixed contact means to close respective circuits therethrough, means biasing respective latch means for rotation to disengage said movable and fixed contacts, a plurality of current-responsive means interposed in respective circuits to move in response to overload current in said circuits for disengaging respective catch means from said latch means to permit rotation of said latch means in response to said bias to open respective circuits, a plurality of cam means rotatable on said shaft, at least one of said cam means being engageable and rotatable by each of said latch means during rotation of said latch means in response to said overload current, pairs of said cam means being connected for common rotation to disengage all of said catch means from said latch means when one of said latch means rotates in response to said overload current, means biasing said manual actuating means to said first switch position, and second latch means normally holding said manual actuating means in said second switch position While said latch means and catch means are engaged, said second latch means being releasable upon manual movement of said manual actuating means for permitting said actuating means to move to said first switch position to open said circuits.

3. A trip-free, ambient-compensated, multipole switching device comprising a housing, a plurality of fixed contact means on said housing, manual actuating means mounted on said housing for movement between first and second switch positions, a shaft carried by said actuating means for movement therewith between said switch positions, a plurality of iirst latch -means rotatably mounted on said shaft, movable contact means mounted on respective latch means, catch means normally adapted to engage respective latch means during movement of said actuating means to said second switch position for rotating said latch means to engage said movable contact means with respective fixed contact means to close respective circuits therethrough, means biasing said latch means for rotation to disengage said movable and dixed contacts, a plurality of first thermally responsive bimetallic means mounting respective catch means and adapted to move independently of said catch means in response to changes in ambient temperature, a plurality of second thermally responsive means adapted to move in response to changes in ambient temperature, said second thermally responsive means being interposed in respective circuits and being adapted to move in response to overload current in said circuits, a plurality of motion transfer means between respective first and second thermally responsive means adapted to move said respective :lirst thermally responsive means together with said catch means to disengage said catch means from said latch means in response to movement of said respective second thermally responsive means when conditioned by overload current therethrough for permitting said latch means to rotate in response to said bias to open respective circuits, a plurality of cam means rotatable on said shaft, at least one of said cam means being adapted to be engaged and rotated by each of said latch means during rotation of said latch means in response to said overload current, pairs of said cam means being connected for common rotation to disengage all of said catch means from said latch means when any one of said latch means rotates in response to said overload current, means biasing said manual actuating means to said iirst switch position, and second latch means normally holding said manual actuating means in said second switch position while said latch means and catch means are engaged, said second latch means being releasable upon manual movement of said manual actuating means for permitting said actuating means to move to said first switch position to open said circuits.

4. A trip-free, ambient-compensated, multipole switching device comprising a housing, lixed contact means on said housing, manual actuating means mounted on said housing for movement between rst and second switch positions, a shaft carried by said actuating means for movement therewith between said switch positions, a plurality of first latch means rotatably mounted on said shaft, movable contact means mounted on respective latch means, a plurality of thermally responsive blade members each pivotally mounted at one end on said housing and having its opposite Iend free for movement in response to changes in ambient temperature, a plurality of catch blades attached at one end to said pivotally mounted ends of respective thermally responsive blades, said catch blades having their opposite ends disposed to normally engage respective latch means during movement of said actuating means to said second switch position for rotating said latch means to engage said movable contact means with respective fixed contact means to close respective circuits therethrough, means biasing said latch means for rotation to disengage said movable and fixed contacts, a plurality of second thermally responsive members each having an end adapted to move in response to changes in ambient temperature, said second thermally responsive means being interposed in respective circuits and being adapted to move at said ends in response to overload current in said circuits, motion-transfer means between said movable ends of respective lirst and second thermally responsive means adapted to move said iirst thermally responsive means together with said catch blades to disengage said catch blades from said latch means in response to movement of said respective second thermally responsive means when conditioned by overload current therethrough for permitting said latch means to rotate in response to said bias to open respective circuits, a plurality of cam follower plates attached to respective catch blades, a plurality of cam means rotatable on said shaft to engage respective cam follower plates, at least one of said cam means being adapted to be engaged and rotated by each of said latch means during rotation of said latch means to respond to said overload current. Pairs of said cam means being connected for common rotation to disengage all of said catch blades from said latch means when any one of said latch means rotates in response to said overload current, means biasing said manual actuating means to said tirst switch position, and second latch means 2,813,168 11/ 1957 Mascioli et al 337-46 X normally holding said manual actuating means in second 3,171,922 3/ 1965 Stokes 337-74 switch position While said latch means and catch means 3,211,862 10/1965 Ellenberger 337-46 are engaged, said second latch means being releasable 3,263,047 7/ 1966 Jencks 337-45 upon manual movement of said manual actuating means 5 3,361,882 1/ 1968 Clarke 337-74 for permitting said actuating means to move to said rst switch position to open Said circuits, BERNARD A. GILHEANY, Prlmary EXammer References Cited H. B. GILSON, Asslstant Exammer UNITED STATES PATENTS 10 U.S. Cl. X.R.

2,367,382 1/ 1945 Taylor .337-46 337-46

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