MECHANISM OF OPERATION FOR CURRENT CIRCUIT CIRCUIT CIRCUIT THAT INCLUDES CLOSURE SYSTEM
Background of the Invention Field of the Invention The present invention is directed, in general, to operating mechanisms for current limiting circuit breakers and, more specifically, to bolt systems in the operating mechanisms. Description of Related Art Circuit-limiting circuit breakers are well known in the state of the art. Examples of such circuit breakers are disclosed in U.S. Patent Nos. 5,416,291 and 5,633,483, which were assigned to the same assignee as the present application, and which are incorporated herein by reference. Basically, a current limiting circuit breaker comprises a base and a cover, a stationary contact, a movable contact secured to a rotating blade, an interruption chamber, an operating mechanism for opening and closing the contacts, and a unit trigger that releases the operating mechanism when a predetermined amount of current is exceeded. The molded-case current-limiting circuit breakers have typically been large, labor-intensive, part-intensive devices that had several areas of part limitations. These circuit breakers provide movable contact arrangements coupled to operating mechanisms that open the circuit to high-level short circuits. This is achieved through the use of thermally responsive firing elements and opening designs by blasting parallel conductors. Therefore, there is a need for continuous improvement of circuit breaker designs that require fewer parts, greater reliability, easier assembly, and compact design. The circuit breaker of the present invention provides a bolt system in an operating mechanism that has fewer parts to assemble than previous circuit breaker designs, allowing for easier assembly and consistent manufacture. The bolt system of the present invention is also simpler and more reliable in use than previous circuit breaker designs. SUMMARY OF THE INVENTION A circuit breaker is disclosed which includes a stationary contact, a movable contact, and a blade having the movable contact attached thereto, the blade being able to rotate about a pivot between an open position and a closed position. . The movable contact links the stationary contact when the blade is in the closed position and the circuit breakers are in the active or on position. An operating mechanism moves the blade between the open position and the closed position. The operating mechanism includes a frame and a bolt system. The bolt system includes a fork having a projection and pivotally coupled to the frame, where the fork is linked to the blade to move the blade to the open position. The bolt system also includes a bolt pivotally coupled to the frame. The bolt has a bolt main surface and a latch bolt protrusion. The main bolt surface provides overlapping linkage of the fork projection when the circuit breaker is in the active or on and non-fired positions. The bolt-linking protrusion is polarized to a position linked to the fork projection when the circuit breaker is in the active or on and non-fired positions, and the bolt-linking protrusion controls the degree of bonding between the main surface bolt and fork projection. A spring biases the main surface of the bolt in overlapping engagement with the fork projection. The fork is linked to the blade, for example by a first link, which has a first end, and a second end, where the first end is pivotally coupled to the fork. The first link is coupled to a second link, which has a first end, a second end, where the first end of the second link is pivotally coupled to the second end of the first link. The second link is coupled to a third link having a middle portion between a first end and a second end, where the middle portion is pivotally coupled to the frame, the first end of the third link is pivotally coupled to the second end of the second link, and the second end of the third link is coupled to the blade to move the blade to the open position. BRIEF DESCRIPTION OF THE DRAWINGS The present invention may be better understood, and its numerous objectives, aspects and advantages made apparent to those skilled in the art, by reference to the accompanying drawings. Figure 1 is a perspective view of a three-pole current limiting circuit breaker constructed in accordance with the present invention; Figure 2 is a longitudinal sectional view of the current limiter circuit breaker of Figure 1, taken generally along line 2-2 of Figure 1 and showing a central pole thereof with parts in a lit position / closed; Figure 3 is a side view, in cross section, of the operating mechanism of the current limiting circuit breaker of Figure 2 in an on / off position; Fig. 4 is a side view, in cross section, of the operating mechanism of the current limiting circuit breaker of Fig. 2 in an off and not fired position; Figure 5 is a side view, in cross section, of the operating mechanism of the current limiting circuit breaker of Figure 2 in a fired / open position; Figure 6A is a perspective view of the latch system of the mechanism of Figure 2; and Figure 6B is a side view of the bolt system of Figure 6A. The use of the same reference symbols in different drawings indicates similar or identical parts. Description of Preferred Embodiment Form (s) For purposes of exemplification, the present invention is illustrated and described with respect to a three-pole circuit breaker, although the circuit breaker latch system of the present invention is equally applicable to circuit breakers of a different number of poles. The circuit breaker disclosed in the present application is designed for top-to-bottom assembly in which all parts are inserted into a circuit breaker base from above and secured to the base by threaded screws in threaded inserts that are molded toward base. Referring to Fig. 1, a circuit breaker 10 is shown having a base 12, a cover 14, a spine 11, the trim cover 16, the access cover 17, the case 15, and the operation handle 18, all preferably made of molded insulating material. The cover 14 secures the components of the circuit breaker in the base 12 and the cover 14 is secured in place from the top using screws. Referring now to Figure 2, a switch assembly is illustrated for the circuit breaker 10, including a handle arm 61, a blade 20, a blade stop 32, a moveable contact 26, a stationary contact 28, a runner arc 30, an overmoulded magnet 34, an arc stack 36, a deflector stack 38, a chamber liner 40, and a current path 42. The current path 42 is shown running along the bottom of the the base 12 and then bending in a generally U-shape around the lower portion of an over-molded magnet 34 having a stationary contact 28 secured thereto using a typical fastening method. The overmoulded magnet 34 comprises a plurality of steel plates grouped together and being overmoulded with thermoplastic. The overmoulded magnet 34 physically surrounds the blade 20, the blade stop 32, the stationary and movable contacts 1 and 28, respectively, a portion of the current path 42, and the arc runner 30. An insulator 190 it is placed between the current path 42 and the overmoulded magnet 34. An arc runner 30 is secured between the overmoulded magnet 34 and the current path 42. The arc runner 30 is automatically connected to the current path 42 at the time of assembly without a brass or solder application operation and does not require additional fasteners to make the electrical connection. A T-shaped insulator 191 is placed on the current path 42 and generally adjacent to the stationary contact 28. The movable contact 26 is secured to the blade 20. The movable contact 26 links the stationary contact 28, which is secured to the upper portion of the current path 42, when the circuit breaker is in the active or on position and the blade 20 is in the closed position. In the operating mechanism 50 of the present invention, a roller bolt, as taught by U.S. Patent Nos. 5,416,291 and 5,633,483, assigned to the assignee of the present application, and incorporated herein by reference, has been eliminated. The roller lock of the circuit breaker designs of the state of the art is extremely difficult to manufacture and assemble, and is not reliable when used. The bolt system of the present invention provides a circuit breaker design that is more reliable and easier to assemble. The operating mechanism 50, as illustrated in Figures 3, 4 and 5, is shown including a pair of upper lever links 52, a pair of lower lever links 54, a pair of bell cranks 56, a fork 58 , a main bolt 62, a pair of tension springs 66 (shown in phantom lines), a knife trap 70, and a torsion spring 72 positioned between two sides 53 of the mechanism (only one side is shown). The bolt system of the present invention, illustrated in greater detail in Figures 6A and 6B, includes a main bolt surface 63 for overlapping engagement of a yoke projection 102 in the yoke 58 when the circuit breaker 10 is in the positions On or active and not triggered. The main bolt 62 also includes a bolt-engaging protrusion 100 polarized to a position linked to the clevis projection 102 when the circuit breaker 10 is in the active and non-fired positions, and where the bolt-engaging protrusion 100 controls the degree of engagement between the main bolt surface 63 and the yoke projection 102. The upper ends of the upper lever links 52 are pivotally connected to the yoke 58 with the pivot pin 78. The lower portions of the upper lever links 52 are pivotally connected to the upper portion of the lower lever links 54 with the lever pin 79. The lower portions of the lower lever links 54 are pivotally connected to the lower ends of the bell cranks in the form of boomerang 56 in the pivot pin 55 which is attached to the bell crank co corresponding 56. The upper ends of the bell cranks 56 have clamping pins 59 which, joined thereto, cooperate with a bell crank traction pin slot 67 on the sides 53 of the frame and link a positioning groove in the carrier of the frame. blade 70. The middle part of the bell cranks is pivotally mounted around a trap pivot pin 51, which is secured to the sides 53 of the frame. The fork 58 rotates around a fork pivot pin 60 which is secured to the sides 53 of the frame at one end. The middle part of the main bolt 62 is rotatably mounted to the sides 53 of the frame with the pivot pin 75 of the main bolt. The surface 63 of the main bolt provides overlapping engagement of the fork projection 102 in the fork 58 when the circuit breaker is in the active or on and non-fired positions, as shown in Figures 3 and 4. The connecting protrusion of lock 100 on main bolt 62 is polarized to a position linked to the fork projection 102 when the circuit breaker 10 is in the active or on and non-fired positions. The lock engaging protrusion 100 controls the degree of bond between the main bolt surface 63 and the yoke projection 102 and provides consistent bonding between the main bolt surface 63 and the yoke projection 102. The main bolt 62 includes a spring from torsion 104 providing a force on the main bolt 62 and for biasing the surface 63 of the main bolt for overlapping engagement of a fork projection 102. A nipple surface 65 is formed at one end of the main bolt 62 to cooperate with the hammer of the trigger unit 80. A knife cross bar 76 is connected to the blade carrier 70 of the three poles to cause the three blade carriers 70 to move simultaneously in response to the opening or closing of the operating mechanism 50. When operating handle 18 is in the active or on / closed position, the parts of the operating mechanism 50 are in position as shown in Figure 3. The upper and lower links 52 and 54, respectively, are in the position above the center, as shown, and have tension springs 66 that supply an ascending tension on the lever pin 79. The spring force that is applied to the lever pin 79 is transferred to the fork 58, through the upper lever links 52, forcing the fork projection 102 to engage the surface of the lever. lock 63 and maintain operating mechanism 50 in the active or on / closed position. Figure 4 illustrates the operating mechanism 50 when the operating handle is in the off or inactive and not triggered position. As illustrated, the surface 63 of the main bolt and the bolt engaging protrusion 100 on the main bolt 62 are biased towards a position linked to the fork projection 102. Figure 5 illustrates the operation mechanism 50 in a fired position. When the trip unit 80 detects an overcurrent or fault condition, it releases the hammer (not shown), which in turn strikes the nipple surface 65 on the main bolt 62 where the main bolt rotates about the pivot pin 75 of the main bolt, causing the latch bolt protrusion 100 and bolt surface 63 to disengage from the yoke projection 102. The tension of tension springs 66 forces the yoke to oscillate upward, pulling the upper lever links 52 toward above. As a result, the upper lever links 52 and the lower lever links 54 are bent at their common point on the lever pin 79, thereby resulting in the upper lever links 52 pulling the lower lever links 54 upwards. , which in turn rotates the bell cranks 56 around the pivot-trap pin 51. The upper end of the bell cranks 56 moves into the positioning slot 71, as shown in Figure 5, forcing the carrier of blade 70 to rotate about blade pivot 74 and separate movable and stationary contacts 26 and 28, respectively. The firing unit 80 (shown in Fig. 2) is illustrated housed in a molded plastic firing unit housing and, for example, is a thermally responsive magnetic firing unit, including an adjustable magnetic firing range, a thermal portion of bi-metal, and a firing mechanism having a hammer to strike the nipple surface 65 of the main bolt 62. The firing unit 80, for example, is the firing unit taught by the United States patents Nos. 5,416,291 and 5,633,483, assigned to the assignee of the present application and incorporated herein by reference. The circuit breaker of the present invention provides a latch system in an operating mechanism that has fewer parts to assemble than previous circuit breaker designs, providing easier assembly and consistent manufacture. The bolt system of the present invention, including the fork projection, the main bolt surface and the latch bolt protrusion, is also simpler and more reliable in use than previous circuit breaker designs, such as those designs which include a roller bolt in addition to a main bolt. Although preferred embodiments have been shown and described, various modifications and substitutions can be made therein without departing from the spirit and scope of the invention. Consequently, it should be understood that the present invention has been described by way of illustration and not limitation.