US2975253A - Contact arm kicker for circuit breakers - Google Patents

Description

March 14, 1961 o. NIMYLOWYCZ 2,975,253

CONTACT ARM KTCKER RoR CIRCUIT BREAKERS Filed July 21, 1958 J /fa BY 2% ff 2l- 5. W 7C/9%@ United States Patent O CONTACT ARM KICKER FOR CIRCUIT BREAKERS Osyp Nimylowycz, Philadelphia, Pa., assignor to I-T-E Circuit Breaker Company, Philadelphia, Pa., a corporation of Pennsylvania Filed July 21, 1958, Ser. No. 749,694

Claims. (Cl. 20G-116) My invention relates to a contact arm kicker for circuit breakers of the molded case type wherein a kicker member is driven into engagement with the circuit breaker contact arm when the circuit breaker contacts are operated to their disengaged position to assure that the contacts will separate.

So-called kicker members have been provided in circuit breaker mechanisms whereby the movable contact arm of the circuit breaker is placed under impact in its opening direction. rl`hus, when the circuit breaker is to be operated to its disengaged position responsive to fault current trip, the kicker member will come into impacting relationship with respect to the Contact arm in order to assure that any welds between the movable contact car ried by the contact arm-and its cooperating stationary contact are broken so that the contact may move to a disengaged position under the influence of the operating mechanism.

The principle of this invention is to provide a kicker member which is of extremely simple construction `and requires only a single pivotal connection to the circuit breaker operating mechanism. One end of the kicker is placed adjacent the contact arm, while the other end of the kicker is positioned `within a slot formed in the molded housing of the breaker. A point between these two ends is then pivotally carried by one of the movable portions of the circuit breaker mechanism whereby movement of the circuit breaker mechanism will carry the kicker into engagement with the contact arm to thereby cause an initial contact separation even though the contacts may be welded together by small welds due to the fault current. The two ends may be further arranged so that a substantial mechanical advantage is available for prying welded contacts apart.

Accordingly, the primary object of my invention is to provide a simple and inexpensive kicker member for circuit breakers.

Another object of this invention is to provide a novel and highly reliable kicker member for molded case circuit breakers which requires only a single connection to the operating mechanism, and affords a mechanical advantage for prying welded contacts apart.

These and other objects of my invention will become apparent from the following description when taken in connection with the drawings, in which:

-Figure 1 shows my novel invention in conjunction with a single pole of a molded case circuit breaker.

Figure 2 is a top view of the kicker member shown in Figure 1.

Figure 3 illustrates the operating mechanism of Figure 1 in conjunction with the kicker member where the circuit breaker is in its closed position.

Figure 4 illustrates the manner in which my novel kicker member operates responsive to overload tripping of the circuit breaker.

Referring now to Figure 1, the circuit breaker which illustrates my novel invention is of the single pole molded case type. 1t is to be understood, however, that the kicker ICC member construction shown in Figure 1 may be utilized in conjunction with any type of molded case circuit breaker, such as the two pole unit set forth in copending application Serial No. 691,867, tiled October 23, 1957, now Patent No. 2,913,542, granted Nov. 17, 1959, in the name of Felix E. Myers entitled Two Pole Circuit Breaker and assigned to the assignee of the instant invention.

The single pole construction of Figure l is contained within a l'molded housing generally identified by numeral 1t), and comprises a first terminal member 12 which is of the plug-in type, and is connected to a stationary contact 14. A movable contact 16 is carried by contact arm 18 and is moved into and out of engagement with respect to stationary contact 14 by the operating mechanisrn to be described hereinafter.

A pigtail 20 is connected to movable contact arm 18 to connect the movable contact arm to the base of bimetal 22. Bimetal 22 has a pigtail 24 connected to its upper end so that the bimetal 22 conducts the Contact current for at least a portion of its length, as seen in Figure 1, and is deected in a predeterminedrnanner responsive to predetermined overload currents.

Pigtail 24 is subsequently connected to an output terminal 26 whereby a current path is completed from terminal 12, stationary contact 14, movable contact 16, contact arm 1S, pigtail 20, bimetal 22, pigtail 24 and terminal 26.

The operating mechanism which controls the movement or" contact arm 1S is seeu in Figures 1, 3 and 4 as comn prising a manual operating handle 2S (Figure l) which is pivotally mounted to the molded housing 10 by pivot pin 30. As may be best seen in Figure 3, the lower portion of operating handle 2S is notched at notch 32 to removably receive the upper end of contact arm 18.

A cradle member 34 is similarly pivotally mounted to the molded housing 10 at pivot 36, and cradle member 34 extends to the right as shown in the gures, and terminates with a iirst latch surface 3S which, as will be seen hereinafter, cooperates with a cooperating latch surface carried by bimetal 22.

The operating spring d() for the operating mechanism is attached at its lower end to a rib of contact arm 18, and its upper end is attached to an intermediate point on cradle member 34 whereby a toggle system is formed which includes cradle member 34, contact arm 18, and spring 40. Thus, when the circuit breaker is in the closed position as shown in the solid line position of Figure l, the toggle will be in an over-center position so as to exert a closing contact force between contacts y14 and 16. Horwever, when the operating handle 28 is rotated in a clockwise direction, the point at which contact arm 18 engages notch 32 will be moved to the left so that the point at which the spring 44) is connected to cradle 34 will be moved to an over-center position whereby the movable contact 16 will be driven to its disengaged position. In a similar manner, the toggle is broken to the right when the cradle 34 is allowed to rotate clockwise because of a removal of the cooperating latch from latch surface 38, as shown in the dotted position of Figure l.

The latch system is completed by a cooperating latch member 42 which is carried by bimetal 22. Birnetal 22 is supported within the molded housing 10 by means of positioning protrusions schematically shown as protrusions 44 and 46 which lie on either side of bimetal 22. The bimetal is then biased in a clockwise direction by the biasing means 48 so that it will normally assume the position shown in Figure l.

In the event that there is an overload current, the bimetal 22 will warp to the right so that the `latch member 42 is removed from the latch surface 38 so that cradle 34 will be rotated clockwise under the force of spring 40. This, in turn, will cause the toggle formed by contact arm 3 18, cradle 34 and spring 40 to break to the right so that the movable contact arm 1S is snapped to its disengaged position.

In accordance with the instant invention, I haveeprovided a kicker member 50 which has one end 52 positioned within a slot 54 of molded housing 1t) which serves as a guide member and has its other end 56 positioned in proximity to the contact arm I8.

A top View of kicker member 50 is seen in Figure 2 which further shows that a centrally located portion of kicker member 5d is provided with an extension 5S. EX- tension S8 cooperates with an aperture 6@ in cradle 34 so that the kicker member 50 is pivotally carried by cradle member 34.

In view of this connection, and by appropriately dimensioning and positioning the kicker member, it will now be apparent that when the cradle 34 rotates in a clockwise direction, the lower end 56 of kicker member 50 will be carried toward the position in which the contact arm It would lie when in the closed position. Thus, as is best seen in Figures 3 and 4, when the latch 42 carried by bimetal 22 is released and the cradle 34 rotates from the position of Figure 3 to the position of Figure 4 (from the solid line position of Figure l to the dotted line position of Figure l), the kicker member S will -be brought to the right. If contact arm 18 remains in the engaged position because of vwelding of the contacts, then the end 56 of kicker member 50 will engage Contact arm I8 with a relatively high impact. This impact will be sufficient to separate any weld which commonly occurs in these types of ybreakers whereby the contact arm 18 will be free to move from the solid line position of Figure 4 to the fully open dotted line position of Figure 4 by virtue of spring 40.

By positioning the upper portion 5'2 of kicker member 50 in the slot 54 of molded housing 18, it will be observed that there is a force multiplication when the kicker mem- -bcr 50 is moved to the right. That is to say, the arm of the kicker member which includes portion 52 is longer than the arm which includes portion 56.

Accordingly, as the kicker member pivot point is moved to the right, arm 50 will be rotated counterclockwise so that the kicker will act as a lever and exert a substantial force in prying the contact arm 18 out ot a welded position.

Although I have described preferred embodiments of my novel invention, many variations and moditications,

will now be obvious to those skilled in the art, and I prefer therefore to Kbe limited not by the specific disclosure herein but only by the appended claims. v

I claim:

l. In a molded case circuit breaker having a movable contact means `and an operating mechanism therefor; a kicker member; said kicker member having a first end positioned adjacent a rst portion of sai-d movable Contact means and a second end movable with respect to and positioned adjacent to a relatively stationary guide member to allow sliding motion between said kicker member and said stationary guide member; an intermediate point of said kicker member being carried by a movable portion of said operating mechanism, said first end of said kicker member being moved towards engagement with said movable contact means when said operating mechanism operates said movable contact means; the motion of said first end of said kicker member being controlled by Said relatively stationary guide member and the motion of said intermediate point of said kicker member.

2. In a molded case circuit breaker having a movable Contact means and an operating mechanism therefor; a kicker member; said kicker member having a rst end positioned adjacent a lirst portion of said movable Contact means and la second end movable with respect to and positioned adjacent to a relatively stationary guide member to allow sliding motion between said kicker member and said stationary guide member; an intermediate point of said kicker member being carried by a movable portion of said operating mechanism, said tirst end of said kicker member being moved towards engagement with said movable contact means when said operating mechanism operates said movable contact means; the motion of said first end of said kicker member being controlled by said relatively stationary guide member and the motion of said intermediate point of said kicker` member; the lever distance from said intermediate point to said first end being smaller than the lever distance from said intermediate point to said second end.

3. In a molded case circuit breaker having a movable contact means and an operating mechanism therefor; a kicker member; said kicker member having a first end positioned adjacent av first portionvof said movable contact means and a second end movable with respect to and positioned adjacent to a relatively stationary guide member to allow sliding motion between said kicker member and said stationary guide member; an intermediate point of said kicker member being carried by a movable portion of said operating mechanism, said first end of said kicker member being moved towards engagement with said movable contact means when said operating mechanism operates said movable contact means; the motion of said first end of said kicker member being controlled by said relatively stationary guide member and the motion of said intermediate point of said kicker member; said first portion of said kicker member striking said movable contact means when said movable contact means remains stationary after operation of said operating mechanism.

4. In a molded case circuit breaker having a movable contact means and an operating mechanism therefor; a kicker member; said kicker member having a rst end positioned adjacent a rst portion of said movable contact means and a second end movable with respect to and positioned adjacent to a relatively stationary guide member to allow sliding motion between said kicker member and said stationary guide member; an intermediate point of said kicker member being carried by a movable portion of said operating mechanism, said rst end of said kicker member being moved towards engagement with said movable contact means when said operating mechanism operates said movable contact means; the motion of said first end of said kicker member being controlled by said relatively stationary guide member and the motion of said intermediate point of said kicker member; the lever distance from said intermediate point to said first end being smaller than the lever distance from said intermediate point to said second end; said kicker member having a substantial mechanical advantage for prying said movable contact means out of its stationary position.

5. In a molded case circuit breaker comprising a rst and second cooperating contact movable into and out of engagement with respect to one another, an operating mechanism operatively connected to said iirst contact to move said tirst contact to said disengaged position and latch means operatively connected to said operating mechanism for rendering said operating mechanism inactive when said latch means is latched, and a trip means operatively connected to said latch means and constructed to unlatch said latch means responsive to a predetermined condition; a kicker member; said kicker member having a lirst end positioned adjacent a first portion of said first Contact and a second end positioned adjacent to and movable with respect to a relatively stationary guide member to allow sliding motion between said kicker member and said stationary guide member; an intermediate point of said kicker member being carried by a movable portion of said operating mechanism, said first end of said kicker member being moved towards engagement with respect to said first Contact when said trip means unlatches said latch means and said operating mechanism is operated.

6r. In a molded case circuit breaker comprising a `first and second cooperating contact movable into and out of engagement with respect to one another, an operating mechanism operatively connected to said first contact to move said first contact to said disengaged position and latch means operatively connected to said operating mechanism for rendering said operating mechanism inactive when said latch means is latched, and a trip means operatively connected to said latch means and constructed to unlatch said latch means responsive to a predetermined condition; a kicker member; said kicker member having a first end positioned adjacent a first portion of said first contact and a second end positioned adjacent to and movable with respect to a relatively stationary guide member; an intermediate point of said kicker member being pivotally connected to a movable portion of said operating mechanism; said pivotal connection being the sole pivotal connection of said kicker member; said first end of said kicker member being moved towards engagement with respect to said first contact when said trip means unlatches said latch means and said operating mechanism'is operated; the motion of said kicker member being controlled by said relatively stationary guide member and the pivotal motion of said intermediate point of said kicker member.

7. In a molded case circuit breaker comprising a first and second cooperating contact movable into and out of engagement with respect to one another, an operating mechanism operatively connected to said first contact to move said rst contact to said disengaged position and latch means operatively connected to said operating mechanism for rendering said operating mechanism inactive when said latch means is latched, and a trip means operatively connected to said latch means and constructed to unlatch said latch means responsive to a predetermined condition; a kicker member; said kicker member having a first end positioned adjacent a first portion of said first contact and a second end positioned adjacent to and movable with respect to a relatively stationary guide member; an intermediate point of said kicker member being pivotally connected to a movable portion of said operating mechanism; said pivotal connection being the sole pivotal connection of said kicker member; said first end of said kicker member being moved towards engagement with respect to said first contact when said trip means unlatches said latch means and said operating mechanism is operated; the motion of said kicker member being controlled by said relatively stationary guide member and the pivotal motion of said intermediate point of said kicker member; the lever distance from said intermediate point to said first end being smaller than the lever distance from said intermediate point to said second end.

8. In a molded case circuit breaker comprising a first and second cooperating contact movable into and out of engagement with respect to one another, an operating mechanism operatively connected to said first contact to move said rst contact to said disengaged position and latch means operatively connected to said operating mechanism for rendering said operating mechanism inactive when -said latch means is latched, and a trip means operatively connected to said latch means and constructed to unlatch said latch means responsive to a predetermined condition; a kicker member; said kicker member having a first end positioned adjacent a first portion of said first contact and a second end positioned adjacent to and movable with respect to a relatively stationary guide member; an intermediate point of said kicker member being pivotally connected to a movable portion of said operating mechanism; said pivotal connection being the sole pivotal connection of said kicker member; said first end of said kicker member being moved towards engagement with respect to said first contact when said trip means unlatches said latch means and said operating mechanism is operated; the motion of said kicker member being controlled by said relatively stationary guide member and the pivotal motion of said intermediate point of said kicker member; said first portion of said kicker member striking said first contact when said first contact remains in said engaged position with respect to said second contact.

9. In a molded case circuit breaker comprising a first and second cooperating contact movable into and out of engagement with respect to one another, an operating mechanism operatively connected to said first contact to move said first contact to said disengaged position and latch means operatively connected to said operating mechanism for rendering said operating mechanism inactive when said latch means is latched, and a trip means operatively connected to said latch means and constructed to unlatch said latch means responsive to a predetermined condition; a kicker member; said kicker member having a first end positioned adjacent a first portion of said first contact and a second end positioned adjacent to and movable with respect to a relatively stationary guide member; an intermediate point of said kicker member being pivotally connected to a movable portion of said operating mechanism; said pivotal connection being the sole pivotal connection of said kicker member; said first end of said kicker member being moved towards engagement with respect to said first Contact when said trip means unlatches said latch means and said operating mechanism is operated; the motion of said kicker member being controlled by said relatively stationary guide member and the pivotal motion of said intermediate point of said kicker member; the lever distance from said intermediate point to said first end being smaller than the lever distance from said intermediate point to said second end; said first portion of said kicker member striking said first contact when said first contact remains in said engaged position with respect to said second contact; said kicker member having a substantial mechanical advantage for prying said first contact away from said second contact when said contacts remain engaged after operation of said operating mechanism. e

l0. In a molded case circuit breaker comprising a first and second cooperating contact movable into and out of engagement with respect to one another, an operating mechanism operatively connected to said first contact to move said first contact to said disengaged position and latch means operatively connected to said operating mechanism for rendering said operating mechanism inactive when said latch means is latched, and a trip means operatively connected to said latch means and constructed to unlatch said latch means responsive to a predetermined condition; a kicker member; said kicker member having a first end positioned adjacent a first portion of said first contact and a second end positioned adjacent to and movable with respect to a relatively stationary guide member; an intermediate point of said kicker member being pivotally connected to a movable portion of said operating mechanism; said pivotal connection being the sole pivotal connection of said kicker member; said first end of said kicker member being moved towards engagement with respect to said first contact when said trip means unlatches said latch means and said operating mechanism is operated; the motion of said kicker member being controlled by said relatively stationary guide member and the pivotal motion of said intermediate point of said kicker member; a projection, integral with and perpendicular to the plane of said kicker member; said movable portion of operating mechanism containing an aperture yto receive said projection; said projection mating with said aperture to form said pivotal connection between said kicker member and and movable portion of said operating mechanism.

References Cited in the file of this patent UNITED STATES PATENTS

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