US2846548A - Automatic circuit breakers - Google Patents

Description

g- 1958 P. M. CHRISTENSEN 2, 8

AUTOMATIC CIRCUIT BREAKERS Origipal Filed April 17, 1951 INVENTOR. P404 44. one/.rravsav ,circuit breaker mechanism operated thereby.

United States Patent AUTOMATIC CIRCUIT BREAKERS Paul M. Christensen, West Orange, N. 1., asslgnor to geetllzral Pacific Electric Company, a corporation of ware Original application April 17, 1951, Serial No. 221,420. and this application May 8, 1956, Serial No.

8 Ciaims. (Cl. 200-172) The present invention relates to automatic circuit breakers and is particularly concerned with that form of circuit breaker in which the mechanism is contained between a pair of molded pieces of insulation forming an enclosing-housing. As will be seen this invention has particular application to that class of circuit breakers in which a moving contact member is part of a sub-assembly that also carries its own current-responsive bimetal-andlatch or actuator.

The present application is a division of accompanying application Serial No. 221,420, filed April 17, 1951, entitled Automatic Circuit Breakers. An object of the present invention is to provide novel structure forming mechanical transmission between an operating handle and A feature of this invention involves the use of multi-part handle whose parts are pivoted to the housing sections, which composite handle furnishes support for one or more elements of the linkage operated by the handle. The illusice! the terminal member 16 is in the form of a prong of the plug-in type as described in the above mentioned application Serial No. 127,433, it will be understood that this is not essential to the present 'invention but onthe contrary a difierent type of terminal member can be provided instead.

The stationary contact 20 is carried by the terminal member 14 in a position within the casing to be engaged by the movable contact 22 carried by the movable contact member 24. Said movable contact member is mounted for pivotal movement between the casing parts 10 and 12 to and from the circuit-closed position-illustrated in Fig. 1, in which contact 22 engages the stationary contact 20, and to and from the circuit-open position illustrated in Fig. 2 in which said movable contact 22 is shown disengaged from said stationary contact 20. This movement may be accomplished manually by the handle 26 which is connected to the channel-shaped actuator 28 by a U-shaped link 30 which is pivotally connected at one end thereof to said handle and at its opposite end to said'actuator as will hereinafter be more specifically described. The actuator .28 is pivotally trative circuit breaker will be seen to include a tension spring one end of which is anchored to a pin of insulation projecting integrally from one of the handle parts; and an operating link co-acts with the handle parts in such fashion as to provide clearance for the spring which is also secured to the handle.

The nature of the invention and further features of novelty will be better appreciated from the following detailed description of an illustrative embodiment of this invention that follows. The illustrative circuit breaker is shown in the accompanying drawings forming part of this disclosure.

In the drawings:

Fig. 1 is a side view of a circuit breaker embodying the present invention, one of the casing parts being removed for the purpose of illustration, the circuit breaker mechanism being shown closed;

Fig. 2 is a view similar to Fig. 1 showing the circuit breaker mechanism open;

Fig. 3 is a sectional view on the line 33 of Fig. 1;

Fig. 4 is a sectional view on the line 4-4 of Fig. 1;

Fig. 5 is an end view of the circuit breaker, both casing parts being in place; and

Figs. 6 and 7 are sectional views on the lines 66 and 7-7 respectively of Fig. 3.

Referring now to the drawings in detail the circuit breaker embodying the present invention comprises a two-part insulation casing having the complementary molded parts 10 and 12 in which the terminals 14 and 16, and the circuit breaker mechanism are mounted, as described for example in application Serial No. 127,433, filed November 15, 1949, by Thomas M. Cole, and in application Serial No. 217,162, filed March 23, 1951, by me and Thomas M. Cole. It will be understood that the two casing parts 10 and 12 are held together by bolts or other suitable means passing through openings 19 in casing part 10 and similar openings in casing part 12 which register with said opening 18 when the two casing parts are in assembled relation. While as here shown,

mounted on the movable contact member as indicated at 32 and is operatively connected to the movable contact member 24 for moving the latter, under the control of the current-responsive latch 34 which includes a bimetallic strip 36 and an electromagnetic device 38, 40 by which said actuator 28 is releasably latched to the movable contact member 24 as described in the abovementioned application Serial No. 127,433. As described in the application Serial No. 217,162, filed March 23,

1951, by me and Thomas M. Cole the pivot for the movable contact member may include the calibration device which comprises a screw 42 having a tapering part 44 and which includes the nut 46. The tapering part 44 engage the movable contact member in an opening 48 adjacent to and laterally in communication with recess 50 in the movable contact member so that by turning the screw 42 in a clockwise direction, viewing Fig. 1, part 24a of the movable contact member may be moved or displaced in a counter-clockwise direction (viewing Figs. 1 and 2) with respect to the other part 24b of the movable contact member to which the latch device 34 is secured, whereby to provide the desired degree of overlap of the part 28a of .the actuator 28, thus to predetermine the amount of flexing of the bimetallic strip 36' in actuator-releasing direction, in response to load condition, for tripping the circuit breaker. Although in the illustrated embodiment, the pivot and calibration device are found as a unit, this is not an essential feature of the present invention and the pivot and calibration may be separate devices as shown, for example, in the abovementioned application of Thomas M. Cole, Serial No. 127,433.

It will be understood that as illustrated in Fig. 1 when the handle 26 is in the on or circuit-closed position thereof and the actuator 28 is latched to the movable contact member 24 by engagement with the outer end of the bimetallic strip 36, as shown, relative pivotal movement between the actuator and the movable contact member is prevented and contact 22 is in engagement with contact 20. In this position, the link 30, which pursuant to the present invention may be a rigid link, and the actuator 28, are in overset toggle condition and that in order for the circuit breaker to open either automatically, i. e., pursuant to the flexing of the bimetal strip 36 either upon heating thereof by the attraction of member 38 to the armature 40 of the electromagnet, the toggle must be broken, and this can take place either by movement of the handle 26 to its circuit-open position (Fig. 2) manually or by release of the end 280 of the actuator by the bimetal strip 36, when the circuit breaker trips upon overload or other predetermined load conditions. The opening of the circuit breaker when the latch 34 releases the actuator 28 is efiected by the spring 52 which is connected at one end thereof to the handle to the part 54 thereof and at its other end to the movable contact member as indicated at 56. It will be observed that said spring is a tension spring and is connected to the movable contact member so as to bias the latter to circuit-open position and to move the latter to the saidposition when latch 34 disengages actuator 28. Also it will be noted that said spring is efiective to move the handle 26 to its otf' or circuit-open position when the circuit breaker is tripped, that is when the movable contact member moves to a circuit-open position pursuant to the release of actuator 28 by latch 34. Further it will be observed that even though the handle 26 is held in on position, said spring is efiective to open the circuit breaker when the latter is tripped, i. e., when latch 34 disengages actuator 28.

A feature of the present invention is the provision of the floating pivot for the movable contact member 24 in conjunction with the spring 52 for permitting a limited bodily movement of the movable contact member and for biasing the movable contact 22 toward the stationary contact 20, in theciosed-circuit position of said movable contact 24 in order to provide the proper pressure between said contacts when they are engaged, or to compensate for wear or other inequalities in the various co operating parts of the circuit breaker. For this purpose, the bearing part 58 of pivot screw 42 and the portion 69 of the companion nut 46 have limited movement in the bearing recesses 62 and 64, respectively, of casing parts 12 and 10, respectively. In this connection it will be observed that hearing recesses 62 and 64 are elongated for slidable engagement, to a limited extent by the corresponding parts 58 and 60 at the pivot device in a direction transversely of the pivot axis. It will be noted that in the closed condition of the circuit breaker as illustrated in Fig. l, in which the movable contact member is restrained against pivotal movement, spring 52, being under tension, biases said movable contact member 24 for bodily movement toward the handle 26, that is in a direction to press movable contact 22 resiliently against the stationary contact 20. In this connection it will be understood further that while spring 52 is thus efiective in this manner to press contact 22 against contact 20 it is also potentially efiective to move the movable contact member 24 pivotallyto circuit-opening position the instant latch 34 operates to disengage or release the actuator 28.

Referring now more specifically to handle 26 and link 30, it will be observed that said handle 26 is here shown in two parts 66 and 68 interlocked with each other, for unitary pivotal movement, by a projection 70 on part 66 which fits into a recess 72 in part 68. The pivotal mounting for said handle comprises the cylindrical projections 74 and 76 on the handle parts which are joumaled in hearing receses 77 and 78 in casing parts and 12, respectively. It will be noted that the inner handle portions 80 v and 82 are spaced from each other in confronting relation and that the part 54 to which spring 52 is connected is integral with handle portion 80 and projects into the space between handleportions 80 and 82. Said portions 80and 82 are also provided with internal projections 84 and 86 forming pivotal bearings for the arms 88 and 90 of link 30 which connects the handle to the actuator 28. Said link also includes a cross member 92 which connects said arms 88 and 90 to each other, and a pivot pin 94 pivotally connects arms 88 and 90 to the adjacent end 'of actuator 28.

It will be understood that various changes in the details of construction and in the arrangement of parts may be made without departing from the underlying idea or 4 principles of the present invention within the scope of the appended claims.

What is claimed is:

l. A circuit breaker, comprising a casing having complementary parts, circuit breaker mechanism disposed between and supported by said parts, said mechanism including a movable contact member and means including a movable handle for actuating the latter, said casing parts having sets of aligned bearing portions for supporting said movable contact member and said handle, respectively, said handle being formed in complementary confronting parts having portions movably supported by said bearing portions, respectively, of the casing, said handle parts having interengaging portions which interconnect the handle parts for joint operation, said handle parts having spaced confronting portions which are disposed within the casing, and link means forming a part of said actuating means connected to said handle in the space between said last mentioned portions of the handle.

2. A circuit breaker, comprising a casing having complementary parts, circuit breaker mechanism disposed between and supported by said parts, said mechanism including a movable contact member and means including a movable handle for actuating the latter, said casing parts having sets of aligned bearing portions for supporting said movable contact member and said handle, respectively, said handle being formed in complementary confronting parts having portionsmovably supported by said bearing portions, respectively, of the casing, said handle parts having interengaging portions which interconnect the handle parts for joint operation, said movable contact member and said handle being pivotally movable in said bearings and said actuating means including -a U-shaped link operatively connected to said movable contact member and pivotally connected to said handle, said handle parts having circular bearing elements which are respectively pivotally engaged by the arms of said U-shaped link for said pivotal connection thereof to the handle.

3. A circuit breaker, comprising a casing having complementary parts, circuit breaker mechanism disposed between and supported by said parts, said mechanism including a movable contact member and means including a movable handle for actuating the latter, said casing parts having sets of aligned bearing portions for supporting said movable contact member and said handle, respectively, said handle being formed in complementary confronting parts having portions movably supported by said bearing portions, .respectively, of the casing, said handle parts having inter-engaging portions which interconnect the handle parts for joint operation, said handle parts having spaced confronting portions which are disposed within the casing, and a spring forming part of said actuating means connected to said movable contact member and to said last mentioned handle portions in the space therebetween.

4. A circuit breaker, plementary parts, circuit breaker mechanism disposed between and supported by said parts, said mechanism including a movable contact member and menu including a movable handle for actuating the latter, said casmg parts having sets of aligned bearing portions for supporting said movable contact member and said handle, respectively, said handle being formed in complementary confronting parts having portions movably by said bearing portions, said handle parts having inter-engaging portions which interconnect the handle parts for joint operation, said handle parts having spaced confronting portions which are disposed within the casing, said movable contact member and said handle being pivotally movable in said bearings and said actuating means including a U-shaped link operatively connected to said movable contact member and pivotally connected to said handle, said handle parts having circular bearing elements which are respectively pivotally engaged by the arms of said U-shaped comprising a casing having com- 0 supported respectively, otthe casing,

' link for said pivotal connection thereof to the handle,

and a spring forming part of said actuating means connected to said movable contact member and to said iast mentioned handle portions in the space therebetween.

5. A circuit breaker, comprising a casing having complementary parts, circuit breaker mechanism disposed between and supported by said parts, said mechanism including a movable contact member and means including a movable handle for actuating the latter, said casing parts having sets of aligned bearing portions for supporting said movable contact member and said handle, respectively, said handle being formed in complementary confronting parts having portions movably supported by said bearing portions, respectively, of the casing, said handle parts having interengaging portions which interconnect the handle parts for joint operation, said handle parts having spaced confronting portions which parts having sets of aligned bearing portions for supporting said movable contact member and said handle, respectively, said handle being formed in complementary confronting parts having portions movably supported by said bearing portions, respectively, of the casing, said handle parts having interengaging portions which interconnect the handle parts for joint operation, said handle parts haviing spaced confronting portions which are disposed within the casing, and a spring forming part of said actuating means connected to said movable contact member and to said last mentioned handle portions in the space therebetween, said bearing portions for said movable contact member comprising integral bearing recesses in said casing and constituting a floating mounting for said movable contact member, said spring being operable in conjunction with said floating mounting for exerting contact pressure in the circuit-making condition of said mechanism.

7. A circuit breaker including a two-part housing of molded insulation having internal part-locating formations, a pair of separable contacts in said housing, mechanism in said housing to open and close said contacts, said mechanism including overload responsive means for causing automatic opening of the contacts and manually operable elements for opening and closing said contacts, said elements including a two-part assembly having a manual lever extending externally of the housing and having coaxial bearings mating with complementary internal housing formations, said two-part assembly being axially separable along the bearing axis thereof when the insulation housing is open and said two-part housing being efiective to retain said two-part assembly together when the two-part housing is closed, said two-part assembly constituting a portion of said mechanism.

8. A circuit breaker, comprising a casing having complementary parts, circuit breaker mechanism disposed between and supported by said parts, said mechanism including a movable contact member and means including a movable handle for actuating the latter, said casing parts having a set of aligned bearing portions for supporting said handle, said handle being formed in complementary confronting parts having portions movably supported by said bearing portions, respectively, of the casing, said handle parts reacting against each other for maintaining assembly thereof in said bearings, and said handle having operative connection to said movable contact member for actuating the latter.

References Cited in the file of this patent UNITED STATES PATENTS 2,050,698 Gaynor Aug. 11, 1936

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