US3421129A

US3421129A - Multipole circuit breaker with sliding contact actuator and swinging latch plate

Info

Publication number: US3421129A
Application number: US555065A
Authority: US
Inventors: Lawrence W Brackett Sr
Original assignee: WOOD ELECTRIC CORP
Current assignee: Siemens Electromechanical Components Inc; WOOD ELECTRIC CORP
Priority date: 1966-06-03
Filing date: 1966-06-03
Publication date: 1969-01-07
Anticipated expiration: 1986-01-07

Description

3,421,129 TUATOR Sheet L. W. BRACKETT. SR MULTIPOLE CIRCUIT BREAKER WITH SLIDING CONTACT AC AND SWINGING LATCH PLATE Jan.'7, 1969 Filed June s, 1966 Jan. 7, 1969 y w. BRACKET-r. SR 3,421,129

MULTIPOLE CIRCUIT BREAKER WITH SLIDING CONTACT ACTUATOR AND SWINGING LATCH PLATE Sheet Z of 4 Filed June 5, k1966 Jan. 7, 1969 L. w. BRACKETT. SR 3,421,129 MULTIPOLE CIRCUIT BREAKER WITH SLIDING CONTACT ACTUATOR AND swINGING LATCH PLATE Filed June 5, 1966 SheetI Jan- 7, 1969 L. w. BRACKETT. SR 3,421,129

MULTIPOLE CIRCUIT BREAKER WITH SLIDING CONTACT ACTUATOR AND SWINGING LATCH PLATE Filed June 5, 1966 Sheet 4 of 4 United States Patent O Claims The yield of the present invention is that of multipole circuit breakers of the so-called trip free type which, after automatically opening due to a faulty circuit condition, cannot be reclosed so long as the fault exists.

IIt is desirable to provide multipole circuit breakers which incorporate proven Contact making and breaking movements including overload tripping mechanisms, in such a manner that an overload in any one conductor will reliably open all contacts while in no Way impairing the normal -circuit making and breaking operations. Such a proven construction as that of the type described in my Patent No. 2,958,749 of Nov. 1, 1960, which, apart from its peculiar double break contact arrangement, makes use of the general movement principle originally described in Patent No. 2,613,296 to Morris B. Wood of Oct. 7, 1952, for a swinging single break contact. Patent No. 2,813,168 to Mascioli et al. of Nov. 12, 1957, deals with a multipole circuit breaker employing the -movement of Wood, 2,613,- 296, which has 4been further developed according to Patent 2,961,513 of Nov. 22, 1960, and Patent 3,021,404 of Feb. 13, 1962, both to Wood, and in my Patent 3,118,034 of Jan. 14, 1964.

Objects of the invention are to provide double break multipole circuit breaker units which utilize single pole circuit breakers of conventional construction such as that of my above mentioned Patent No. 2,958,749, with some modifications of the individual Ibreaker movements; to provide such multipole breaker units which are composed of an optimally minimal number of the components that are necessary for a single pole breaker movement of the same type; and to provide such circuit Ibreaker units which are especially compact and simple in construction, which are easily assembled, and which are comparatively inexpensive in manufacture and yet rugged and reliable in operation.

The substance of the invention can be shortly stated as follows.

Multipole circuit breaker units according to the present invention employ known circuit breaker constructions involving sliding (such as double break) contacts, and actuating motions related by locking (such as latch and catch) means to detector (such as thermal and if desired also a magnetic) and trip mechanisms, these components functioning essentially in the manner of corresponding components according to my above-mentioned Patent 2,958,749. In combination with a plurality of movable (preferably double break sliding) contacts, a plurality of detector and and trip mechanisms one for each pole, and a single actuating motion having a sliding member, the present invention introduces a contact actuator with a sliding bar which is rigidly connected to the sliding member of the motion and to all movable contacts, and which is guided on the breaker housing.

In a preferred embodiment the common housing is subdivided 4by partitions which essentially separate the contacts of the respective poles excepting for slots which have the purpose of guiding the contact actuator slide bar which is common to all movable contacts.

According to another aspect of the invention, the trip mechanism has a swinging latch plate with tension springs particularly suited for the present purpose, and a terminal ICC and conduit assembly including a bimetal element, and suita-ble for association with a half-turn magnet.

According to a further aspect of the invention, the sliding member of the motion is a cam incorporated in the sliding bar as an integral part of a molded plastic body into which are inserted metallic fasteners for individual bridges carrying the movable contacts, forming a reliable unitary construction.

These and other useful objects, and aspects of the substance and nature of the invention will appear from the following description of a practical embodiment illustrating its novel characteristics.

The description refers to drawings in which FIG. 1 is an laxonometric View of a triple pole breaker according to the invention;

FIG. 2 is a section on lines 2-2 of FIG. 3, showing the contacts in normally closed position;

FIG. 3 is a section on lines 33 of FIG. 2;

FIGS. 4 and 5 are partly fragment-ary views of the actuating motion with contact and trip mechanism as also shown in FIGS. 2 and 3, but in normally open, and tripped open conditions, respectively;

FIG. 6 is an axonometric view of the contact slide bar according to the invention;

FIG. 7 is `a section on lines 7 7 of FIG. 6; and

FIG. 8 is a section on lines 8 8 of FIG. 7.

FIG. l shows the exterior of a triple circuit breaker according to the invention. A conventional insulating housing 10 (FIGS. 1, 2 and 3) encloses a central single breaker motion with an operator button such as 11, as will be described in detail below. While for reasons of symmetrical force distribution the invention is particularly applicable to circuit breakers with an odd number of poles and hence pairs of movable contacts, it can be adopted for evennumbered multiples.

The housing can lbe made with closed walls excepting one open side which is closed by a cover plate 12 with sealing gasket 13. The housing may be completely sealed, since the various components can be introduced through the open side or sealed into walls. As shown in FIG. l the cover is xed to the housing with appropriate means such as screws 27. FIG. 1 also indicates screws for fastening terminal bars and magnets and for bimetal element adjustment at 14 and 15, respectively, as will be described below with reference to FIG. 2. Internal portions such as supporting blocks for various subassemblies are preferably molded separately and upon assembly joined to the housing by cementing or similar conventional techniques. This is especially true of the two partitions 16, 17 (FIGS. 3 and 7) with

guide slots

18, 19. Wherever essential, internal recesses for receiving components of the detecting, tripping and actuating subassemblies will be appropriately described together with the latter.

The triple circuit breaker herein described by Way of example has a central main breaker complete with actuating motion including operator button, thermally as well as magnetically responsive overload detector, and tripping assembly, essentially according to my Patent No. 2,958,- 749. This breaker is in a central compartment and on each side thereof, in its own compartment, is a companion breaker having double break contacts on a bridge and an overload detector, similar to those of the main breaker. The contact bridges of all breakers are related to the central breaker motion by a contact actuator. The three overload detectors are interrelated by a tripping assembly with a latch for locking and unlocking a catch of the central breaker motion and with provisions enabling it to be actuated by either one of the three detectors. The central breaker with its main actuating motion will first be described, then the detector and trip mechanisms, and then the contact actuator device in the combination according to the invention.

The central or main actuating motion is operated by a Wedging member such as a set of rolls 22 on a link 23 which is at 24 pivoted on the above-mentioned Ibutton 11 of insulating material. The pivot pin 24 Slides in appropriate grooves 24.1 of the housing shell. The button 11 itself'slides in a sleeve 26 which is appropriately xed to the housing cover 12. The actuating motion proper has a swinging cam member 32 and a sliding cam member 33 (FIGS. 2, 4 and 5). The swinging cam member is rotatably and slidingly mounted on a pivot pin 3S passing through a loose fitting slot 39 of 32, and biased towards the rolls 22 by a spring 34. The swinging cam 32 has two

riding surfaces

35, 36 for engagement with the roller system 22, and a tooth 32.1 (FIGS. 4 and 5) which is normally engaged by a nose 68 of the latch plate 66 to be described below.

The overload detector and trip mechanism is similar for all three breakers. Each breaker has a bimetal element 41 suitably fastened, such as by welding, to a terminal and conduit bar 42 which has two fork prongs 42.1, 42.2 (FIGS. 3 and 4). These prongs are secured in appropriate slots of the housing shell and the partition walls, as clearly shown in FIG. 3. The excursion of the free end of the bimetal can be adjusted by means of the abovementioned screws 15. The normal (cool) and abnormal (hot) excursions of the bimetal element are indicated at c (dot and dash lines) and h, respectively, of FIG. 5. In addition a so-called half-turn magnet overload detecting device is provided. This consists of a U-shaped magnetic core 45 through which the conduit bar 42 passes, as clearly indicated in FIG. 2 and further described as to construction and function in my above-mentioned Patent No. 2,958,749. The magnet and the bar are fastened to the housing by the above-mentioned screws 14.

Common to the three overload detector devices is a latch plate assembly 61 which is constructed as follows. For the two companion breakers are provided metal plates 61.1 and 61.2, respectively, each with two hangers as indicated at 61.11 and 61.12 in FIGS. 2 and 3 for the plate 61.1. Between plates 61.1 and 61.2 is a metal latch plate 61.3 without hangers, for the central detector. These three plates, namely the hanger plates 61.1 and 61.2 and the latch plate 61.3 are mounted on a common swing plate 62 of insulating material, which is notched at 63, near the upper edge of the latch plate 61.3, opposite the main actuating motion. Within the notch 63, the plate 61.3 has the previously mentioned latch nose 68 (FIGS. 3 and which cooperates with the catch tooth 32.1 of the swinging cam 32. Opposite each half-turn magnet the latch plate assembly 61 has armature plates, as indicated for one companion breaker at 69 of FIGS. 2 and 3. One of the hangers of each hanger plate 61.1, `61.2 has a dimple, as indicated at 61.5, 61.6. The central latch plate 61.3 has an extension with a similarly located dimple 61.7. These dimples are opposite of, and cooperate with the ends of the bimetal strips 41. As indicated in FIGS. 2 and 3, the swing plate 62 has fastened thereto spring brackets 71, 72 to which springs 73, 74 are fastened which at the other end are attached to

pins

75, 76 in appropriate recesses of the housing shell and partition walls. This construction permits the use of strong tension springs for reliable operation of the trip mechanism.

Referring now particularly to FIGS. 2, 6, 7, and 8, the contact actuator device has a slide bar 101, a slide cam 33 and three

contact bridges

105, 106, 107 each of which carries two contact pieces as in Patent 2,958,749 and clearly indicated (FIG. 2) opposite the corresponding fixed contacts, by way of example at 108.1 and 109.1, 108.2 and 109.2, for bridge 106. The contact bridges are made of appropriate yielding as well as conductive material such as beryllium copper. The contact bridges are associated with two springs, one being indicated at 112 in FIG. 2 and the other at 113 of FIG. 8. The association of these springs with the contact bridge 107 is indicated at 107, 113 in FIG. 7. The springs are at one end 4 conned in recesses 115 (FIGS. 2, 4, 5) of the housing whereas the other end is held in place by the crimped projection of a corresponding slide bar insert, as will be described below.

The upper fixed contacts such as 109.1 are carried on contact and terminal bars 126 which have at the other ends connector terminals 127 with provisions for joining lead wires, for example threaded holes 128 (FIG. 2). The bars 126 are confined within the insulating housing by means of appropriate inserts which are conventional and not specifically shown in the drawings. The other set of xed contacts 109.2 is carried by three respective conductor bars 131 (FIGS. 2 and 3) which are confined between the housing wall proper and arcing barriers 132 with liners 134 (FIG. 2). The other ends of the contact bars 131 are conductively fastened, such as soldered, to pigtails 136 which lead at 137 to the respective bimetal elements 41, as shown in FIG. 2. The outer ends of the conductor ybars 42 of the detector mechanism lead through the housing and constitute terminals 137 with holes 138, similar to terminals 127 of bars 126. As above described, the

bars

42, 137 pass through the magnets 45. It will now be evident that the circuit of each individual breaker goes from terminal 137 by way of the half turn magnet bar 42 through bimetal element 41, flexible conductor 136, contact bar 131, fixed contact 109.2, movable contact 108.2, bridge 106, movable contact 108.1, fixed contact 109.1, `bar 126, to terminal 127.

The slide bar 101 (FIGS. 6 to 8) is made from plastic material 140 molded around three

steel inserts

141, 142, 143 which have several perforations for better fixation to the surrounding plastic material 140, and each can have one larger opening 147 which leads through the entire slide ybar including the plastic portion and can serve for receiving a conductor leading from one to the other moving contact if the bridge itself should not provide sutlicient conductivity. In this manner this bridging conductor is protected and kept away from other metallic parts. The sliding cam member 33 is of the same material, and formed together with, the outer portion 140 of the bridge 101. In this embodiment, the cam has a recess 33.1 for the purpose of clearing the nose 32.5 of the swinging cam 32 (FIG. 4).

The metal inserts of the slide bar have prior to assembly coplanar lugs as shown in FIG. 7 at 141.1. Upon assembly these lugs are crimped over upon longitudinal windows of the contact bridges, as shown at 141.2 0f FIG. 7.

The contact slide bar 101 is guided in the previously mentioned

slots

18 and 19 of the partition walls 17 and 18. As shown in FIG. 2, these slots terminate within the housing wall allowing for elastic dellection of the contact bridges 105, 106, 107. At the inner ends the slots are closed by

plugs

151, 152 after the slide bar 101 is inserted. The springs 112 provide a considerable opening force opposing the action of roller 22 on the sliding cam 102.

The operation of the above-described triple circuit breaker is as follows.

Under normally closed conditions the button 11 is depressed and the roller 22 held in the position shown in FIGS. 2 and 3, wedging the sliding cam 33 against the force of springs 112. It will be noted that the catch tooth 32.1 of the swinging cam 32 is then engaged by the latch nose 68 of the trip mechanism.

For normally opening the circuit breaker, the button 11 is pulled upwardly which removes the roller 22 from the central actuating motion and permits canr 33 and slide bar 101 to move to the position shown in FIG. 4. It will be noted that the configuration of the detector and trip mechanism has not changed from that indicated at c of FIG. 5 so that, upon again depressing the button the catch will come to rest on the latch nose 68 and the bridge will be moved by sliding cam 33 in its slots, closing the contacts.

Upon detection of abnormal current ow in one of the lines, the respective bimetal element will move from position c into position h, and under certain conditions as explained in my Patent No. 2,958,749 the respective armature (indicated by 69) of the swing assembly 61 will be attracted, if a magnet trip is used. Either event removes the latch nose of the swing from under the catch tooth 32.1 of the central movement, either by direct magnet action or by the bimetal element in position h pressing on one of the dimples 67. This condition is shown in FIG. 5. The -catch tooth drops, cam member 32 rotates against the `force of springs 112, the slide bar is moved inwardly, and all breaker contacts open. It will be evident that the button will now return into the open position according to FIG. 4 due to the action of spring 34. However, repeated pressing of the button cannot result in closing the contacts so long as the abnormal condition prevails, since the motion will always yield lacking support of catch 32.1 by latch 68. This so-called trip-free operation is full explained in my above referred to prior patents.

It will now be understood that this circuit breaker involves minimal reconstruction of readily available movements for single circuit breakers of this type, The central main movement can be retained practically Without change whereas the companion breaker movements are simply omitted, retaining only the detecting latch plate subassembly. The interconnecting slide bar 101 with cam 33 is very simple and inexpensive in manufacture and assembly and still very reliable due to its secure and stable guidance in the

slots

18 and 19 of the partition walls which separate the individual breakers.

It should be understood that the present disclosure is for the purpose of illustration only and that this invention includes all modifications and equivalents which fall within the scope of the appended claims.

I claim:

1. In a multipole circuit breaker comprising Within a housing a plurality of xed and corresponding movable `contact means, -an actuating motion for the movable contact means with a sliding cam member, a swinging cam member, and a wedging member therebetween, and with locking means for the swinging cam member capable of retaining the motion in normal operating conditions, and

a plurality of detector and trip mechanisms separately sensitive to an abnormal condition in any one pole for releasing the locking means of the actuating motion upon occurrence of such abnormal condition,

the improvement which comprises:

a contact actuator supporting movable contact means for a plurality of poles, extending between the actuating motion and the corresponding fixed contact means for said plurality of poles and including a sliding bar carrying said movable contact means, being supported on the housing and having said sliding cam member attached thereto for control of the movable contact means by said wedging member during normal operating condition;

a swinging plate interposed between said detector and trip mechanisms and said actuating motion and carrying said locking means for the swinging cam member; and

biasing means for opening the contacts by moving the sliding bar upon release of the locking means by abnormal conditioning of any one of said plurality of detector and trip mechanisms.

2. Circuit breaker according to claim 1 wherein the sliding bar carries said movable Contact means side by sidet on one edge and said cam member oppositely thereof, said lbar being formed of insulating material integrally with the sliding cam member and having metal inserts which are insulated from each other by the insulating material and to which the movable contact means are fastened.

3. Circuit breaker according to claim 2 wherein the movable contact means include flexible conductive bridges carrying contacts near their ends and being at their intermediate portions lixed to the metal inserts of the sliding bar and which further includes springs resting with one end at the region of attachment of the respective conductive bridge to its metal insert, and resting with the other end on the housing.

4. Circuit breaker according to claim 1 wherein the housing has partitions separating respective contact means of the poles and having slots forming guiding supports for the sliding bar.

5. Circuit breaker according to claim 4 wherein the slots are formed in the partitions with openings toward the housing interior, permitting insertion of the sliding bar, and which includes plugs for closing the openings with the bar in place.

References Cited UNITED STATES PATENTS 2,107,246 2/1938 Jackson 200--116 2,195,016 3/1940 Swingle 200-116 2,306,244 l2/ 1942 Butler 200--116 2,703,351 3/1955 Hulbert 200-116 2,889,428 6/1959 Kingdon et al. ZOU-116 2,958,749 11/1960 Brackett 20G-116y BERNARD A. GILHEANY, Primary Examiner.

HAROLD BROOME, Alssz'stant Examiner.

U.S. Cl. X.R. 335-22

Claims

1. IN A MULTIPOLE CIRCUIT BREAKER COMPRISING WITHIN A HOUSING A PLURALITY OF FIXED AND CORRESPONDING MOVABLE CONTACT MEANS, AN ACTUATING MOTION FOR THE MOVABLE CONTACT MEANS WITH A SLIDING CAM MEMBER, A SWINGING CAM MEMBER, AND A WEDGING MEMBER THEREBETWEEN, AND WITH LOCKING MEANS FOR THE SWINGING CAM MEMBER CAPABLE OF RETAINING THE MOTION IN NORMAL OPERATING CONDITIONS, AND A PLURALITY OF DETECTOR AND TRIP MECHANISMS SEPARATELY SENSITIVE TO AN ABNORMAL CONDITION IN ANY ONE POLE FOR RELEASING THE LOCKING MEANS OF THE ACTUATING MOTION UPON OCCURRENCE OF SUCH ABNORMAL CONDITION, THE IMPROVEMENT WHICH COMPRISES: A CONTACT ACTUATOR SUPPORTING MOVABLE CONTACT MEANS FOR A PLURALITY OF POLES, EXTENDING BETWEEN THE ACTUATING MOTION AND THE CORRESPONDING FIXED CONTACT MEANS FOR SAID PLURALITY OF POLES AND INCLUDING A SLIDING BAR CARRYING SAID MOVABLE CONTAT MEANS, BEING SUPPORTED ON THE HOUSING AND HAVING SAID SLIDING CAM MEMBER ATTACHED THERETO FOR CONTROL OF THE MOVABLE CONTAT MEANS BY SAID WEDGING MEMBER DURING NORMAL OPERATION CONDITION; A SWINGING PLATE INTERPOSED BETWEEN SAID DETECTOR AND TRIP MECHANISMS AND SAID ACTUATING MOTION AND CARRYING SAID LOCKING MEANS FOR THE SWINGING CAM MEMBER; AND BIASING MEANS FOR OPENING THE CONTACTS BY MOVING THE SLIDING BAR UPON RELEASE OF THE LOCKING MEANS BY ABNORMAL CONDITIONING OF ANY ONE OF SAID PLURALITY OF DETECTOR AND TRIP MECHANISMS.