US3426301A - Interconnected multipole circuit breaker - Google Patents

Description

C. A. BODGE INTERC ONNECTED MULTIPOLE CIRCUIT BREAKER Feb.4, 1969 Sheet i of 5 Filed Dec. 20,

Feb. 4, 1969 c. A. BODGE 3,426,301

INTERCONNECTEI) MULTIPOLE CIRCUIT BREAKER Filed Dec. 20, 1966 Sheet g of s c. A. some;

Feb. 4, 1969 INTERCONNECTED MULTIPOLE CIRCUIT BREAKER Sheet Filed Dec. 20, 1966 United States Patent 3 Claims ABSTRACT OF THE DISCLOSURE A mechanism for interconnecting the poles of a multipole circuit breaker to disengage the contacts in all of the poles upon disengagement of the contacts in any one of the poles and particularly for circuit breakers of the type wherein each pole is provided with fixed and movable contacts operated by an interconnecting toggle linkage. Each toggle linkage is provided with a latch for tripping it to disengage the contacts in one pole in response to an electromagnetic overload sensing device. A rotary shaft, interconnecting the poles, is provided with means, one for each pole, for tripping all of the toggle linkages in all poles when one is tripped upon overload so as to disengage all of the contacts of the breaker.

Background 0 the invention The invention belongs in the multipole circuit breaker art in which disengagement of the contacts in all of the poles occurs upon disengagement of the contacts in any one of the poles.

In the past, various attempts have been made to interconnect the poles in a multipole circuit breaker for interrupting the flow of current through all of the poles upon the occurrence of an overload condition in any one of the poles. The most common mechanism for accomplishing this is provided with a shaft extending between the poles with a plurality of lobes projecting therefrom, a lobe in each pole being located so as to coordinate with the motion of the contact arm and the armature in a pole. An overload in any one of the poles causes the contact arm to engage the lobe associated therewith and rotate the shaft and the remaining lobes into engagement with the armatures in each of the poles, the armatures then operating latches to disengage all the contacts. This type of mechanism requires the contact arm, shaft assembly, and armatures of all of the poles to be held to very close tolerances to ensure pole-to-pole operation of the latches. Any small shifting of the parts will cause a malfunction since the armatures are relatively insensitive and must be rotated by the lobes through a considerable distance before the armatures actuate the latches. The distance is not a problem when the armature is actuated by the overload sensing means but becomes critical when actuated 'by the lobe. For example, in a present commercial design, each pole must be calibrated to trip within tolerance between .010 and .020 inch before the armature reaches the limit of its travel to ensure tripping of the latches by the lobe actuated armature. This requires that each of the poles be adjusted to and cannot shift more than .010 inch relative to each other. In a circuit breaker employing, for example, six poles, this tolerance limitation becomes very critical, thereby materially increasing the cost and decreasing the reliability of such devices. In addition, all of the prior art mechanisms utilize the motion of the end of the contact arm to operate the armatures of adjacent poles. Since the force available at the end of the contact arm is relatively low in the contacts-open position, the additional problem of inadequate force available for unlatching adjacent poles is presented by this type of circuit breaker.

Summary of the invention Accordingly the present invention overcomes these difficulties by providing an interconnecting mechanism which operates directly on the latches without first operating the armatures. This reduces the distance that the interconnecting mechanism must travel before tripping the contacts. Since the latch is very sensitive, as opposed to the armature as set forth above, this interconnecting mechanism ensures tripping of all the contacts.

An interconnected multipole circuit breaker constructed in accordance with the present invention is composed of a plurality of poles, each pole being comprise-d of a pair of contacts, one of which is carried by a :movable arm for movement into and out of engagement with the other of the contacts. Means including a toggle linkage assembly is connected to the movable arm for normally maintaining engagement of the contacts and a latch is provided for collapsing or tripping the toggle assembly to cause disengagement of the contacts. Overload sensing means is provided for operating one latch in one pole in response to a predetermined condition, and interconnecting means is provided for disengaging the contacts in all of the poles upon disengagement of the contacts in said one pole. The interconnecting means comprises means interconnecting all of the poles and operated by the movable arm in the pole wherein the contacts first disengage for operating the latches in each of the remaining poles to disengage the contacts therein.

Brief description 0 f the drawings FIG. 1 is a side elevation of the circuit breaker of the present invention with portions .of the housing fragmented and showing the circuit breaker contacts in the on or contacts-closed position;

FIG. 2 is a left-handed end elevation of FIG. 1, partly in section, showing a two pole circuit breaker constructed in accordance with the present invention;

FIG. 3 is an enlarged side elevation similar to FIG. 1 with portions of the device omitted for clarity of illustration and showing the circuit breaker contacts in the off or contacts-open position;

FIG. 4 is an enlarged fragmentary elevation of a por tion of the invention showing the contacts in the on or contacts-closed position; and

FIG. 5 is an enlarged fragmentary elevation similar to FIG. 4 but showing the contacts in an otf or contactsopen position.

Corresponding reference characters indicate corresponding parts throughout the several views of the drawings.

Description of the preferred embodiment Referring particularly to FIGS. 1 to 3, a preferred structural embodiment of one pole of a multipole circuit breaker 1 is illustrated. In the interest of simplicity of description, some of the details of the circuit breaker not necessary to a full understanding of the invention will be omitted. However, a complete description of the construction and operation of the circuit breaker mechanism per se may be obtained by reference to US. Patent 3,388,357 based on application 577,086 which is a continuation of the application of Clifford A. Bodge and Martin W. Lawson, Ser. No. 298,536, filed July 26, 1963, and now abandoned, and assigned to the same assignee as the present application 603,360. The circuit breaker 1 is comprised of a housing 3 having a pair of side portion 5 and a bottom portion 7, the housing being formed of a suitable electrically insulative material such as, for example, a moldable, phenolic resin. The housing 3 constitutes supporting means for the circuit breaker mechanism. Housing 3 contains suitable openings 9, 11 for receiving conductive terminals 13 and 15, respectively. Terminal 13 carries an electrically conductive contact plate 17 carrying a fixed contact 19'. The housing 3 further includes upper and lower end portions 21 and 23 extending the width of the housing 3, the lower end portion 23 including apertures 25 receiving fasteners 27 for retaining the housing side portions in tight-fitting engagement. Mounted on the top of housing 3 is a cover member 29 having tab portions 31 bracketing the housing 3 and apertured at 33 for receiving a pair of fasteners 35.

The circuit breaker 1 includes a toggle lever assembly, generally indicated by reference character 37, which is comprised of a toggle operating lever 39, formed of insulating material, received within an opening 41 formed within the upper end portion 21 of the housing 3. The cover 29 includes an opening 43 through which toggle lever 39 projects, the opening 43 being of a size sufficient to allow for movement of the toggle lever 39 between the on position illustrated in FIG. 1 and the off position illustrated in FIG. 3. Cover opening 43 is also sufficiently large to allow viewing of the lever surfaces 45, 47, which may be printed with the wording off and on, respectively.

Toggle lever 39 is provided with an extension 53 and is pivotally mounted on a pin 49 supported on a toggle frame 51. A toggle spring 55, one end of which abuts a portion of the frame 51 and the other end of which abuts a portion of extension 53, urges the toggle assembly 37 toward the off position illustrated in FIG. 3. The toggle frame 51 extends downwardly through the housing 3 and forms a support 63 for supporting an overload or current sensing assembly 65, the latter being comprised of an electromagnet 67 having a coil 69 and a core 71. One end of the coil 69 is electrically connected through a conductor 73 to the terminal 15 and the other end of the coil is connected to a flexible conductor 75 by a connector 77. An armature 79 is pivotally mounted on a shaft 81 secured to the toggle frame 51 for pivotal movement towards and away from the electromagnet core 71. Armature 79 is urged to rotate in a counterclockwise direction, as viewed in FIG. 1, into engagement with a tab 83 formed on frame 51 by a spring 85 coiled about an adjustable pin 87. The tab portion 83 acts as a calibrated stop for armature 79 and may be bent or calibrated to control the amount of electromagnetic force necessary to cause the armature 79 to pivot about shaft 81 and engage the armature core 71. Armature 79 includes a core engaging portion 89 extending in a first direction and a pair of legs 91, 93 extending in a second direction. The end of leg 91 is provided with a camming surface 95, the purpose of which will be hereinafter set forth, while leg serves as a balancing extension to counterbalance the armature 79 and 91.

Mounted on the lower portion of frame 51 is a conductive switch arm or contact arm 97 having a moveable contact 99 secured thereto for movement into and out of engagement with the fixed contact 19. The contact arm 97 is electrically connected through connector 101 to the end of conductor 75. Thus a completed electrical circuit may be provided through terminal 15, coil 69 of electromagnet 67, conductor 75, contact arm 97, movable contact 99, fixed contact 19, and terminal 13.

Contact arm 97 is provided with an elongate slot 103 having a pin 105 extending thererthrough and engaging a pair of legs 106 formed on the frame 51. The contact arm 97 is urged by spring 107 towards rotation in a clockwise direction, as viewed in FIG. 1, from the contactsclosed position to the contracts-open position. One end of spring 107 bears against leg 106 of frame 51 and the other end bears against the contact arm 97. The contact arm 97 is connected to the toggle lever 39 by a collapsible toggle linkage assembly 109. The assembly 109 includes a lower link 111 pivotally connected to contact arm 97 by a pivot pin 113, and to a center link 115 by a pivot or hinge pin 117. The other end of the center link 115 is connected to the extension 53 by a pivot pin 119 tocomplete the toggle linkage assembly 109.

As best illustrated in FIG. 1, the pivot point at pivot pin 117 may take a position to the left of a line passing through the centers of pins 113 and 119. A tab portion 121 formed on lower link 111 bears against the center link 115 in the tripped position of parts shown in FIG; 3. If forces are applied at the ends of the linkage assembly 109, that is, at pins 113 and 119, the linkage assembly will tend to collapseto the left as shown in'FIG. -3. This is prevented, however, by a rotary latch releasing mechanism 123 which provides a stop against pivotal movement of the center link 115 about pin 117. Rotary latch 123 is mounted on a slotted shaft 125 which rotates with-the latch 123, the shaft 125 having a solid-right-hand half 127 normally engaging a lip 129 formed in the. lower portion of center link 115 to pervent rotation of link 115 about pin 117 and collapse of the assembly 109. However, upon clockwise rotation of the rotary latch 123 and the shaft 125, the solid half 127 of the shaft 125 is rotated out of engagement with the lip 129, thereby releasing the center link 115 and permitting the same to rotate about the shaft 117 to effect collapse or'tripping of the toggle linkage assembly 109. A spring 131 is coiled about the shaft 125 for biasing the rotary latch 123 against a stop 120 on link 111 in a counterclockwise direction as viewed in the FIG. 1.

In operation, the circuit breaker 1 is connected to the circuit or component to be protected at terminals Band 15. Previously the device has been calibrated by bending tab 83 and tensioning spring to fix the amount of the electromagnetic force required to actuate armature 79, and hence to determine the amount of overload required to trip the circuit breaker and interrupt the flow of current therethrough. The toggle lever 39 is then switched to the on or contact-closed position illustrated in FIG. 1 wherein the links 111 and 115 of linkage assembly 109 act rigidly to swing arm 97 counterclockwise so as to move contact 99 into engagement with stationary contact 19.

When an overload condition occurs in the circuit through electromagnet 67, the armature 79 is actuated and pivoted about shaft 81 to move the camming surface into engagement with lug 122 on the rotary latch 123 and rotate the latch 123 and slotted shaft 125. In this movement the surface 95 passes by stop 120. As the solid half 127 of the shaft 125 rotates past the lip 129 of the lower link 115, the link is released and the linkage 109 is unconstrained and allowed to collapse to the left as viewed in FIG. 3. The releasing action of the latch 123 occurs only instantaneously. When this occurs, contact arm 97, acting under the force of spring 107, moves to the contacts-open position and interrupts the flow of current through the circuit breaker 1' to protect the controlled circuit connected to terminals 13 and 15. It should be noted that since contact arm 97 is retained in the contacts-open position by spring 107, the circuit breaker 1 cannot be reclosed until toggle lever 39 is manually moved to the on position. It should further be noted that circuit breaker 1 may be provided with alternative circuit paths and terminal arrangements for permitting either current or voltage overload sensing. For example, the electromagnet coil 69 may be connected in a separate circuit from the terminals 13, 15 to permit voltage, and current sensing.

As set forth above, the purpose of the present invention is to cause disengagement of the contacts in all'of the poles of a multipole circuit breaker upon disengagement of the contacts in any one of the poles. For example, a circuit operated by a two or three phase power supply requires the use of a two or three-pole circuit breaker, respectively, to ensure that each phase of the supply is protected. Should an overload occur in one of the phases it is desirous that the power supply to all of the phases be interrupted. Accordingly, the present invention provides such a mechanism and FIG. 2 illustrates a two-pole circuit breaker for use, for example, with a two-phase power supply. It should be understood however that any number of poles may be provided and interconnected in a row in the manner to be described.

The poles of the two-pole circuit breaker illustrated in FIG. 2 may be secured together by passing the fasteners 27, 35 through both of the housings 3, 3'. The means for interconnecting the poles for disengaging all of the contacts upon disengagement of either one of the contacts comprises a continuous shaft 133 mounted for rotation in the outer side walls of the circuit breaker housings 3, 3. The shaft 133 extends through openings 135, 135 formed in the inner side walls of the housings 3, 3' and is provided with a plurality of upwardly projecting camming means or camming lobes 137, 137', one being provided for each pole. As illustrated in FIGS. 1 and 4, in the contacts-closed position each of the camming lobes 137 projects upwardly from the shaft 133 to a position intermediate a contact arm tab 139 formed on the contact arm 97 and a downwardly projecting finger or tripping member 141 formed on the rotary latch 123. The contact arm tab 139 is formed adjacent the contact arm shaft 105 and is provided with a flange 143 constituting drive means for engaging the camming lobe 137 so as to be operatively connected therewith upon rotation of the contact arm 97 about the shaft 105. A spring 145 is coiled about the shaft 133 and engages the camming lobe 137 and the side wall 5' of the housing 3 for biasing the shaft and camming lobes in a clockwise direction as viewed in FIGS. 1 and 4, flange 143 acting as a stop.

Operation is as follows. The circuit breaker is connectedat terminal 13, 15 and 13', 15' to the circuit or component to be protected and the toggle levers 39, 39 moved to the on or contacts-closed position. When an overload occurs in any one of the poles of the circuit breaker, as detected by the electromagnet 67 therein, the armature 79 in that pole is caused to pivot about the shaft 81 causing the camming surface 95 on the armature leg 91 to engage and rotate the rotary latch 123 and slotted shaft 125. When the solid half 127 of the slotted shaft 125 disengages the lip 129 of the center link 115, the toggle linkage assembly 109 in that pole is tripped and collapses so that the contact arm 97 rotates about the shaft 105 under the urging of spring 107 to disengage the contacts 99 and 19 in that pole. As best illustrated in FIGS. 4 and 5, when the contact arm in the first pole to receive an overload condition rotates and moves upward to the position shown in FIGS. 3 and 5, the flange 143 formed on the contact arm tab 139 engages and rotates the lobe 137 associated therewith. Rotation of the lobe 137 causes the shaft 133 to rotate, thereby rotating the camming lobe 137 into engagement with the downwardly projecting finger 141' formed on the rotary latch 123' to rotate the latch 123' and the slotted shaft 125' and permit the remaining toggle assembly 109 to collapse and disengage or trip open the contacts 19, 99. Thus it is seen that an overload condition in any one of the poles causes the contact arm in that pole to rotate the camming lobe and shaft, whereupon the remaining camming lobes operate the remaining rotary latches and cause all of the contacts to disengage. To reset the multipole circuit breaker, the toggle levers 39, 39' are rotated to the on or contacts-closed position. Since the shaft 133 is biased by spring 145 in a clockwise direction, the lobes 137, 137' follow flanges 143, 143 on the contact arm tabs 139, 139 back to the position illustrated in FIG. 4 and permit the rotary latches 123, 123' to rotate into engagement therewith.

An important feature of the invention is that the tripping of one contact brought about by action of its armature part 91 does not effect tripping of any other contact indirectly through action of its armature but rather directly by operation of its latch 123 from a lobe 137 on shaft 133.

It will be noted in all of the above embodiments that upon tripping of one pole all the other poles are tripped. This action takes place independently of any restraint on the toggle, providing multipole trip free action.

In view of the above, it will be seen that the several objects of the invention are achieved and other advantages results attained.

As various changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

1. An interconnected multipole circuit breaker, each pole of which comprises supporting means first and second electrical contacts mounted in said supporting means, a movable arm mounted one of said cont-acts for movement into and out of engagement with the other of said contacts for controlling an electrical circuit, manually operable means mounted in said housing and movable between first and second positions for moving said movable arm, a linkage assembly connected between said manually operable means and said movable arm, said linkage assembly comprising an extension of said manually operable means, and center and lower pivotally joined links, said lower link having a rotary latch mounted thereon for movement into and out of engagement with said center link to effect collapse of said linkage assembly and movement of one of said contacts out of engagement with the other of said contacts, current responsive means in said housing having a movable member movable in response to a predetermined current flow, said movable member including portions engageable with said rotary latch to operate the latter and effect collapse of said linkage assembly, and means for effecting collapse of the linkage assemblies in all of said poles upon collapse of the linkage assembly in any one of said poles, means comprising a rotatably mounted shaft passing through all of the poles of said circuit breaker, said shaft having a plurality of camming members thereon, one for each pole, said camming members being engageable with the movable arm and rotary latch in each of said poles, whereby collapse of the linkage assembly in one of said poles causes the movable arm in that pole to engage and rotate the camming member and shaft associated therewith, thereby causing the remaining camming members to rotate the remaining rotary latches and collapse all of the linkage assemblies.

2. A multipole circuit breaker comprising a row of poles, each pole including a switch arm spring biased to move to open-circuit position, a toggle mechanism for moving the switch arm to closed-circuit position against the spring bias, tripping means for the toggle to release the arm to move to open-circuit position under the spring bias, an electro-magnetically operated armature responsive to excess load current to operate said toggle tripping means,

a continuous rotatable shaft extending across the row of poles, multiple camming means carried on and simlultaneously operated by said shaft, one camming means being located in each pole for actuating the toggle tripping means therein independently of movement of the armature in the respective pole,

and drive means on each switch arm operatively connected with the one of the camming means for operating it and the shaft in response to switch opening movement of the respective arm in one pole thereby to cause each other camming means to operate a toggle tripping means in each of the other poles.

3. A circuit breaker according to claim 2, wherein each switch arm has a lost-motion connection with a fixed pivot for initial rotary movement when the switch arm is driven toward closed-circuit position and a second motion other than around the pivot for actuating on of said camming means.

References Cited UNITED STATES PATENTS 3,307,002 2/1967 Cooper 200- -1=1'6 3,353,127 1'1/1967 Francis 20O'116 US. Cl. X.R. 200-116

Images