Electricity: magnetically operated switches – magnets – and electr – Electromagnetically actuated switches – Automatic circuit-interrupting devices
Patent
1983-09-29
1985-08-20
Goldberg, E. A.
Electricity: magnetically operated switches, magnets, and electr
Electromagnetically actuated switches
Automatic circuit-interrupting devices
335 35, H01H 7512
Patent
active
045367264
DESCRIPTION:
BRIEF SUMMARY
DESCRIPTION
TECHNICAL FIELD
This invention relates to a circuit breaker interposed between the power source and a load so that when an abnormality is detected in the load, the power supply to the load is cut off.
BACKGROUND OF INVENTION
A conventional circuit breaker is constructed as shown in FIG. 17, in which a current flows from a terminal block 71 to terminal 77 through a stationary contact 72, a movable contact 73, a movable arm 74, a bimetal 75 and a stranded wire 76 in that order. A handle 78, as shown in FIG. 17, it tilted leftwardly and contacts 72 and 73 are in contact with each other by a link 79, a hook segment 80 and the movable arm 74, so as to be well-balanced. In this state, when a overload current flows in the circuit, the bimetal 75 curves downwardly to push down a movable magnetic plate 81 and release it from the hook segment 80, whereby the movable arm 74, link 79 and hook segment 80 are unbalanced and a spring 82 turns the movable arm 74 in the reverse direction around a shaft 83 to disconnect the contacts 72 and 73. When a short-circuit current flows, the magnetic flux generated around the bimetal 75 instantaneously attracts the movable magnetic plate 81 toward the stationary magnetic plate 84 so that the hook segment 80 disengages from the movable magnetic plate 81, thereby disconnecting the contacts 72 and 73 the same as the above. In addition, in FIG. 17, reference numeral 85 designates a tension spring interposed between the movable magnetic plate 81 and the movable arm 74, which is disposed around a stem 86 and biases the free end of movable magnetic plate 81 upwardly or away from the stationary magnetic plate 84.
In such a conventional example, however, a contact switching mechanism to open or close the contacts 72 and 73 through operation of handle 78 is not separate from the contact breaking mechanisms, such as link 79 and hook segment 73, to disconnect the contacts, but integral with each other. The hook segment 80, when the contacts are to be cut off, disengages from the movable magnetic plate 81 and at once rotates around a shaft 87 and thereafter the movable arm 74 turns. Hence, there has been a problem in that it takes a long time to actually disconnect the contacts 72 and 73 after detection of abnormal load. Also, even when the contacts 72 and 73 are intended to be disconnected with a larger gap therebetween, the gap is restricted because the handle 78 and movable arm 74 are connected through the link 79 and hook segment 80. Furthermore, the contact open-closing mechanism and contact cutoff mechanism in this example are integral with each other, whereby the contact cutoff mechanism is subjected to mechanical stress each time the handle 78 is hand-operated to open or close the contacts, especially subjected to the maximum strength in the transition from open condition to close condition, thereby having created a problem in that the mechanism is liable to be damaged.
SUMMARY OF THE INVENTION
This invention has been designed to solve the problems in the conventional example. An object of the invention is to provide a circuit breaker which is provided with a contact open-closing mechanism for switching the contacts by operating the handle and a contact cutoff mechanism for disconnecting the contacts when the load is abnormal, both the mechanisms being separate from each other, so that the contacts can be disconnected in a short time, a gap between the disconnected movable contact and stationary contact can be increased, and the mechanical stress applied to the contact cutoff mechanism when hand-operated can be reduced.
Next, an embodiment of a circuit breaker of the invention will be described in accordance with the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective exterior view of an embodiment of the circuit breaker of the invention;
FIG. 2 is a perspective view of the FIG. 1 embodiment with the casing opened up;
FIGS. 3 and 4 are perspective exploded views of the components of the same;
FIG. 5 is a sectional view of the FIG. 1 embodiment in
REFERENCES:
patent: 3462716 (1969-08-01), Yorgin et al.
patent: 3517355 (1970-06-01), Cole
Andrews George
Goldberg E. A.
Matsushita Electric & Works Ltd.
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