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US 4,908,594 AGranted
Thermal overload relay
AssigneeFuji Electric Co., Ltd.
InventorsKatsumi Akiike, Haruo Ichikawa
Life of this patent
Estimating the term…
Abstract
A thermal overload relay comprising a change-over spring mechanism and a contact mechanism that is separated from the spring mechanism. The contact mechanism is actuated by the spring mechanism, which is driven by a bimetallic strip when an overcurrent flows through the strip. The spring mechanism has no electrically conducting portion. The change-over point of the spring mechanism varies only a little, thus enhancing the reliability. The spring mechanism is easy to assemble and adjust.
Claims11
A thermal overload relay comprising:
- a. a bimetallic strip adapted to be deformed when an overcurrent flows therethrough;
- b. a change-over mechanism comprising:
- a shifter connected to an end of said bimetallic strip to be shifted thereby upon deformation of said bimetallic strip,
- a rotatable release lever having a first end and a second end, said first end contacting said shifter to rotate said release lever in response to said shifting of said shifter;
- and
- a spring mechanism having a first spring for engaging said second end of said release lever and a second spring, said first spring having a first stable state, a second stable state, and a free end, said second spring for moving said first spring from said first stable state to said second stable state in response to rotation of said release lever;
- and
- c. a contact mechanism including a contact support engaged with said free end of said first spring for establishing a first contact condition when said first spring is in said first stable state and a second contact condition when said first spring is in said second stable state,
- wherein said change-over mechanism and said contact mechanism are assembled independently and said change-over mechanism possesses no electrically conductive portion in either said first stable state or said second stable state.
6 more elements
A thermal overload relay comprising:
- a. a bimetallic strip adapted to be deformed when an overcurrent flows therethrough;
- b. a change-over mechanism comprising:
- a shifter connected to an end of said bimetallic strip to be shifted thereby upon deformation of said bimetallic strip,
- a rotatable release lever having a first end and a second end, said first end contacting said shifter to rotate said release lever in response to said shifting of said shifter, and
- a spring mechanism having a first spring for engaging said second end of said release lever and a second spring, said first spring having a first stable state, a second stable state, and a free end, said second spring for moving said first spring from said first stable state to said second stable state in response to rotation of said release lever;
- and
- c. a contact mechanism including a contact support engaged with said free end of said first spring for establishing a first contact condition when said first spring is in said first stable state and a second contact condition when said first spring is in said second stable state;
- and
- d. means for adjusting the force required to cause said first spring to move from said first stable state to said second stable state,
- wherein said change-over mechanism and said contact mechanism are assembled independently and said change-over mechanism possesses no electrically conductive portion in either said first stable state or said second stable state.
7 more elements
Dependencies are inferred from the claim text.