Patent US859674A successfully refreshed from Google Patents.
US3723929A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Bimetallic circuit overload protector
Assignee: Siemens Energy and Automation Inc
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Filing: 1972-04-07
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Granted: 1973-03-27
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Expires: 1992-04-07
Abstract
Abstract A thermal overload protector for electrical circuits usable in single and multiphase circuits. A bimetallic element actuates a snap action switch in response to excess current in a heater connected in the circuit. An adjusting cam engages a switch element to permit adjustment of the operating value over a range while a reset cam can be actuated to provide for manual or automatic reset. Part of the switch operating linkage can be formed from a bimetal to provide an ambient compensating element. Also included are screws acting on the actuating linkage to permit precise adjustment during manufacture to compensate for such manufacturing tolerances as may exist. The protector may be constructed in either a normally closed or a transfer contact configuration.
Inventors
- 👤 C Sitar
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 06:43
CPC Classifications
H; H01; H01H; H01H73/00; H01H73/22; H01H73/30
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
290 words
An improved electrical circuit protection device comprising: a housing; a plurality of pairs of terminals mounted on said housing for connection in an electrical circuit to be protected; an electrical heating element extending between each terminal in a pair of terminals; a bimetallic strip, anchored at one end so as to have flexing movement toward the interior of said housing at its opposite free end in response to increased temperature, mounted on said housing beneath each heating element; a pivoted lever assembly mounted in said housing spaced from said terminals; a coupler having a plurality of first extensions, each engaging a free end of one of said bimetallic strips; said coupler also having a plurality of second extensions extending oppositely from said first extensions and engaging the free end of said pivoted lever assembly to cause it to move in response to movement of any one of said bimetallic strips; an actuating lever pivotally mounted on said lever assembly and substantially coextensive therewith; a switch supporting bracket mounted in said housing between said bimetallic strips and said lever assembly; a movable contact mounted on said switch supporting bracket; a coil spring extending between said switch supporting bracket and said movable contact tending to urge said movable contact in one direction; an actuator engaging said spring and said actuating lever to exert a force on said spring when said actuating lever moves downwardly in response to downward movement of said pivoted lever assembly; a first terminal disposed externally of said housing and means electrically connecting said first terminal to said movable contact; a second terminal disposed externally of said housing; a first relatively fixed contact in said housing; and means electrically connecting said second terminal to said first relatively fixed contact.
Claim 2
Dependent Claim
290 words
An improved electrical circuit protection device comprising: a housing; a plurality of pairs of terminals mounted on said housing for connection in an electrical circuit to be protected; an electrical heating element extending between each terminal in a pair of terminals; a bimetallic strip, anchored at one end so as to have flexing movement toward the interior of said housing at its opposite free end in response to increased temperature, mounted on said housing beneath each heating element; a pivoted lever assembly mounted in said housing spaced from said terminals; a coupler having a plurality of first extensions, each engaging a free end of one of said bimetallic strips; said coupler also having a plurality of second extensions extending oppositely from said first extensions and engaging the free end of said pivoted lever assembly to cause it to move in response to movement of any one of said bimetallic strips; an actuating lever pivotally mounted on said lever assembly and substantially coextensive therewith; a switch supporting bracket mounted in said housing between said bimetallic strips and said lever assembly; a movable contact mounted on said switch supporting bracket; a coil spring extending between said switch supporting bracket and said movable contact tending to urge said movable contact in one direction; an actuator engaging said spring and said actuating lever to exert a force on said spring when said actuating lever moves downwardly in response to downward movement of said pivoted lever assembly; a first terminal disposed externally of said housing and means electrically connecting said first terminal to said movable contact; a second terminal disposed externally of said housing; a first relatively fixed contact in said housing; and means electrically connecting said second terminal to said first relatively fixed contact.
Claim 3
Dependent Claim
27 words
An improved eLectrical circuit protection device as set forth in claim 1 including an adjustable element mounted beneath said movable contact assembly to limit its downward movement.
Claim 4
Dependent Claim
107 words
An improved electrical circuit protection device as set forth in claim 2 wherein said adjustable means comprises an elongated spring member fixed at one end and free to move at its other end and an intermediate portion thereof is positioned in the path of movement of said movable contact so that when said elongated spring member is moved to one position it will be engaged by and limit the movement of said movable contact as it is operated and when moved to another position it will permit greater movement of said movable contact and said coil spring will tend to urge said movable contact in another direction.
Claim 5
Dependent Claim
39 words
An improved electrical circuit protection device as set forth in claim 3 having a rotatable element with a portion extending externally of said housing and engaging the free end of said elongated spring member whereby it may be adjusted.
Claim 6
Dependent Claim
44 words
An improved electrical circuit protection device as set forth in claim 4 including a third terminal on the exterior of said housing, a second relatively fixed contact on said adjustable element and means electrically connecting said third terminal to said second relatively fixed contact.
Claim 7
Dependent Claim
32 words
An improved electrical circuit protection device as set forth in claim 4 wherein said rotatable element includes a cam portion and one end of said elongated spring member engages said cam portion.
Claim 8
Dependent Claim
34 words
An improved electrical circuit protection device as set forth in claim 6 including means formed on said housing and in said rotatable element for receiving means to prevent the rotation of said rotatable element.
Claim 9
Dependent Claim
88 words
An improved electrical circuit protection device as set forth in claim 1 wherein said movable contact is normally urged by said coil spring toward engagement with said first relatively fixed contact and upon movement of said coupler lever assembly, actuating lever and actuator in response to the movement of any one of said bimetal strips caused by the heat developed in an associated heating element as the result of excess current flow in a circuit being protected said movable contact will move away from said relatively fixed contact.
Claim 10
Dependent Claim
39 words
An improved electrical protection device as set forth in claim 8 wherein said means connecting said second terminal to said first relatively fixed contact includes a leaf spring secured at one end free to move at its other end.
Claim 11
Dependent Claim
55 words
An improved electrical circuit protection device as set forth in claim 9 including a rotatable adjusting element having a portion extending externally of said housing and having a portion engaging the free end of said leaf spring whereby the leaf spring may be moved upward or downwardly in response to movement of said adjusting element.
Claim 12
Dependent Claim
41 words
An improved electrical circuit protection device as set forth in claim 10 wherein said adjusting element is provided with a cam surface interiorly of said housing and the free end of said leaf spring is in contact with said cam surface.
Claim 13
Dependent Claim
94 words
An improved electrical circuit protection device as set forth in claim 1 including a reset actuator mounted in said housing and having a portion disposed exteriorly thereof, spring means engaging said reset actuator to urge it outwardly of said housing and means on said reset actuator overlying a portion of said movable contact whereby when said reset actuator is moved inwardly against the force of the spring and said movable contact assembly is in one position the movement of said manual reset actuator will be effective to cause it to move to another position.
Claim 14
Dependent Claim
29 words
An improved electrical circuit protection device as set forth in claim 12 including adjustable means positioned beneath said manual reset actuator to limit its movement inwardly of said housing.
Claim 15
Dependent Claim
33 words
An improved electrical circuit protection device as set forth in claim 13 wherein said housing is provided with an opening therein to provide Access to said adjustable means whereby it may be adjusted.
Claim 16
Dependent Claim
87 words
An improved electrical circuit protection device as set forth in claim 1 including a manual trip plunger having a portion extending externally of said housing, spring means engaging said manual trip plunger to urge it outwardly of said housing, said manual trip plunger being disposed above said movable contact whereby when said manual trip plunger is depressed inwardly of said housing against the force of said spring it will engage said movable contact assembly and cause it to move from a first position to a second position.
Claim 17
Dependent Claim
53 words
An improved electrical circuit protection device as set forth in claim 1 wherein said actuating lever is formed of a bimetallic material arranged so that its free end moves in a direction opposite to the direction of movement of said bimetallic strips so as to provide compensation for variations in the ambient temperature.
Claim 18
Dependent Claim
54 words
An improved electrical circuit protection device as set forth in claim 16 including an adjusting screw threaded into said housing and having an end engaging said actuating lever to permit adjustment of the device to a desired operating value and wherein an opening is provided in said housing for access to said adjusting screw.
Claim 19
Dependent Claim
88 words
An improved electrical circuit protection device as set forth in claim 4 wherein said movable contact is normally urged by said coil spring toward engagement with said first relatively fixed contact and upon movement of said coupler lever assembly, actuating lever and actuator in response to the movement of any one of said bimetal strips caused by the heat developed in an associated heating element as the result of excess current flow in a circuit being protected said movable contact will move away from said relatively fixed contact.
Claim 20
Dependent Claim
40 words
An improved electrical circuit protection device as set forth in claim 19 wherein said means connecting said second terminal to said first relatively fixed contact includes a leaf spring secured to one end free to move at its outer end.
Claim 21
Dependent Claim
55 words
An improved electrical circuit protection device as set forth in claim 19 including a rotatable adjusting element having a portion extending externally of said housing and having a portion engaging the free end of said leaf spring whereby the leaf spring may be moved upward or downwardly in response to movement of said adjusting element.
Claim 22
Dependent Claim
41 words
An improved electrical circuit protection device as set forth in claim 20 wherein said adjusting element is provided with a cam surface interiorly of said housing and the free end of said leaf spring is in contact with said cam surface.
Claim 23
Dependent Claim
94 words
An improved electrical circuit protection device as set forth in claim 21 including a reset actuator mounted in said housing and having a portion disposed exteriorly thereof, spring means engaging said reset actuator to urge it outwardly of said housing and means on said reset actuator overlying a portion of said movable contact whereby when said reset actuator is moved inwardly against the force of the spring and said movable contact assembly is in one position the movement of said manual reset actuator will be effective to cause it to move to another position.
Claim 24
Dependent Claim
87 words
An improved electrical circuit protection device as set forth in claim 22 including a manual trip plunger having a portion extending externally of said housing, spring means engaging said manual trip plunger to urge it outwardly of said housing, said manual trip plunger being disposed above said movable contact whereby when said manual trip plunger is depressed inwardly of said housing against the force of said spring it will engage said movable contact assembly and cause it to move from a first position to a second position.
Claim 25
Dependent Claim
44 words
An improved electrical circuit protection device as set forth in claim 23 including a third terminal on the exterior of said housing, a second relatively fixed contact on said adjustable element and means electrically connecting said third terminal to said second relatively fixed contaCt.
Claim 26
Dependent Claim
53 words
An improved electrical circuit protection device as set forth in claim 24 wherein said actuating lever is formed of a bimetallic material arranged so that its free end moves in a direction opposite to the direction of movement of said bimetallic strips so as to provide compensation for variations in the ambient temperature.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-03-26 | 1976-09-25 | 1977-03-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-03-26 | 1980-09-25 | 1981-03-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-03-26 | 1984-09-25 | 1985-03-27 | $7700.00 | Window Closed / Lapsed |