1. Field of the Invention
The invention relates generally to circuit interrupters and, more particularly, to operating mechanisms for circuit interrupters, such as a battery disconnect apparatus.
2. Background Information
Circuit interrupters, such as, for example, battery disconnect switches, are employed to provide protection for the electrical power circuit of a vehicle. For example, some vehicles, such as trucks and cars, employ direct current (DC) disconnecting switches to provide a rapid mechanism to disconnect batteries or other DC power supplies in the event of serious electrical faults. Disconnecting switches may also be employed by vehicles such as, for example, electric vehicles such as golf carts and fork lifts, to disconnect alternating current (AC) power supplies.
Battery cable circuit protection devices, such as battery disconnect devices (BDDs) and battery cut off switches (BCOs), are known to be employed, for example, to disconnect the electrical system (e.g., without limitation, 12 VDC; any suitable DC or AC voltage) of the vehicle in response to a significant collision, or for maintenance during periods of inactivity. Such devices typically employ an operating mechanism having a movable electrical contact which is moved into and out of electrical contact with a number of stationary electrical contacts electrically connected to the battery cable. The movable electrical contact sometimes has a tendency to undesirably separate from the stationary electrical contact(s) when the vehicle is subjected to various shock and vibration loads (e.g., without limitation, rough terrain; pot holes; sudden stops; abrupt turns; collisions). Among other disadvantages, such unintentional separation of the electrical contacts presents an arcing hazard.
Prior proposals have attempted to accommodate such loads by employing an operating mechanism for the battery disconnect device which, for example, has an arrangement of springs, levers and/or solenoids. However, such designs are relatively complex, and thus expensive. Additionally, if the movable electrical contact is brought into electrical contact with the stationary electrical contact(s) too rapidly, it can undesirably bounce with respect to the stationary electrical contact(s), resulting in the undesirable arcing hazard noted above. Solenoids are generally fast-acting and can produce this undesirable result if utilized improperly. Solenoids can also be relatively large, heavy and expensive.
For instance, in some conventional mechanisms, the cam member directly drives the opening and closing of the electrical contacts. As such, the cam member generates the entire force required to move the contacts. Over an extended period of time, the force required of the cam member may cause deformation of the member and thereby, preclude its proper operation.
There is a need, therefore, for an improved operating mechanism for circuit interrupters, such as a battery disconnect apparatus, which not only provides resistance to arcing hazards caused, for example, by unintentional separation of the electrical contacts of the apparatus, but which is also relatively small, lightweight and cost-effective.
There is, therefore, room for improvement in operating mechanisms for circuit interrupters, such as a battery disconnect apparatus.
These needs and others are met by embodiments of the invention, which provide an operating mechanism for a circuit interrupter, such as a battery disconnect apparatus, wherein the operating mechanism employs a cam member and a two-bar linkage to open and close electrical contacts and to hold the contacts closed. Further, the operating mechanism of the invention resists the electrical contacts of the battery disconnect apparatus from separating unintentionally, for example, in response to shock and vibration loads which are commonly experienced by a vehicle.
Accordingly, the operating mechanism of the invention can provide benefits over related conventional mechanisms known in the art. In the present invention, the cam member cooperates with the two bar linkage to move the electrical contacts. The cam member drives the two-bar linkage and in turn, the linkage drives the contacts. Since the cam member is not directly driving the contacts, a lower force is required of the cam member in order to generate the contact force necessary to open and close the electrical contacts and hold the contacts closed. For example, a two pound force from the cam member to the two-bar linkage would generate about ten pounds of contact force to the electrical contacts. As a result, a fast open and close time of the contacts can be achieved with a lower motor torque, which can allow for a smaller motor, less gearing, and reduced costs.
As one aspect of the invention, an operating mechanism for a circuit interrupter includes a housing and a number of stationary electrical contacts enclosed by the housing. The operating mechanism comprises: a cam member structured to be rotatably coupled to the housing, a two-bar linkage member comprising a first bar, a second bar, and a pivot member disposed between the first bar and the second bar; a movable contact assembly comprising a movable electrical contact, the movable contact assembly being structured to cooperate with the two-bar linkage member to move the movable electrical contact into and out of electrical contact with the number of stationary electrical contacts; and an actuating assembly structured to rotate the cam member between a first position structured to maintain the movable electrical contact of the movable contact assembly in electrical contact with the number of stationary electrical contacts, and a second position being structured to release the movable contact assembly such that the movable electrical contact is movable out of electrical contact with the number of stationary electrical contacts.
As another aspect of the invention, an operating mechanism is provided for a circuit interrupter, which includes a housing and a number of stationary electrical contacts enclosed by the housing. The operating mechanism comprises: a cam member structured to be rotatably coupled to the housing; a two-bar linkage member having a profile, the profile having a first bar and a second bar wherein the first and second bars are connected by a pivot pin; a movable contact assembly comprising a movable electrical contact, the movable contact assembly being structured to cooperate with the linkage member in order to move the movable electrical contact into and out of electrical contact with a number of stationary electrical contacts; and an actuating assembly structured to rotate the cam member between a first position and a second position. In the first position, the cam member cooperates with the two-bar linkage member to move the pivot pin and push the linkage member in an upward direction such that the movable electrical contact of the movable contact assembly is in electrical contact with the number of stationary electrical contacts; and in the second position, the cam member cooperates with the two-bar linkage member such that the pivot pin can move and the opening spring pushes the linkage member in a downward direction to release the movable contact assembly in order that the movable electrical contact is movable out of electrical contact with the number of stationary electrical contacts.
The movable contact assembly may comprise at least one spring element structured to move the movable electrical contact toward and/or away from the number of stationary electrical contacts.
The actuating assembly may comprise a motor and a plurality of gears. A corresponding one of the gears may be coupled to the motor, and each of the gears may have a plurality of teeth. In response to movement of such corresponding one of the gears by the motor, the teeth may be cooperable in order that all of the gears are movable. The gears may comprise a drive gear coupled to the motor, a cam gear coupled to the cam member, and a number of reduction gears disposed intermediate the drive gear and the cam gear. The cam gear can be cooperable with the cam member to rotate the cam member into its first or second position such that the movable electrical contact is in electrical contact with the stationary electrical contacts or the movable electrical contact is released from electrical contact with the stationary electrical contacts, respectively. The actuating assembly may include a means, such as a sensing device or combination of relays, to determine when the cam member is in the first or second position such that the power can be disconnected to prevent further rotation of the cam member once positioned and thus, the open or closed position of the electrical contacts can be maintained.
For example, to open the electrical contacts, power can be applied to a motor which causes the cam member to rotate to a position where the pivot pin of the two-bar linkage member is capable of moving. An opening spring can then push the movable electrical contact and the two-bar linkage member in a lateral direction away from the stationary electrical contacts into their open position. To close the electrical contacts, power can be reapplied to the motor to rotate the cam member against the pivot pin of the two-bar linkage member, pushing the linkage member and the movable electrical contacts in a lateral direction against the stationary electrical contacts to a closed position. Power to the motor then can be disconnected to assure that the cam member remains in its position such that the closed position of the electrical contacts is maintained. A sensing device or a combination of relays can be employed to detect when the electrical contacts are in the closed position and thus, causing the power to the cam member to be disconnected.
Electrical contacts which are in a closed position may be opened in response to a short circuit, arc fault, ground fault or other related conditions. External sensors can be used to detect such conditions and to initiate opening of the electrical contacts by, for example, supplying power to the motor to rotate the cam member to the appropriate position.
A full understanding of the invention can be gained from the following description of the preferred embodiments when read in conjunction with the accompanying drawings in which:
The invention is described in association with a battery disconnect apparatus for a vehicle, although the invention is applicable to a wide range of circuit interrupters for direct current (DC) (e.g., without limitation 12 VDC; 24 VDC; 42 VDC; 60 VDC; and any suitable direct current voltage) or alternating current (AC) powered systems.
Directional phrases used herein, such as, for example, left, right, top, bottom, upper, lower, front, back, clockwise, counterclockwise and derivatives thereof, relate to the orientation of the elements shown in the drawings and are not limiting to the claims unless expressly recited therein.
As employed herein, the term “vehicle” shall expressly include, but not be limited by, a land vehicle, a marine vehicle, an air vehicle or another motor vehicle.
As employed herein, the term “land vehicle” shall expressly include, but not be limited by, any land-based vehicles having pneumatic tires, any rail-based vehicles, any maglev vehicles, automobiles, cars, trucks, station wagons, sport-utility vehicles (SUVs), recreational vehicles, construction vehicles, off road vehicles, all-terrain vehicles, farm vehicles, fleet vehicles, motor homes, vans, buses, motorcycles, mopeds, campers, trailers, or bicycles.
As employed herein, the term “marine vehicle” shall expressly include, but not be limited by, any water-based vehicles, ships, boats, other vessels for travel on water, submarines, or other vessels for travel under water.
As employed herein, the term “air vehicle” shall expressly include, but not be limited by, any air-based vehicles, airplanes, jets, aircraft, airships, balloons, blimps, or dirigibles.
As employed herein, the terms “fastener” and “fastening mechanism” refer to any suitable connecting or tightening material or device expressly including, but not limited to, screws, bolts and the combinations of bolts and nuts (e.g., without limitation, lock nuts) and bolts, washers (e.g., without limitation, lock washers) and nuts.
As employed herein, the statement that two or more parts are “coupled” together shall mean that the parts are joined together either directly or joined through one or more intermediate parts.
As employed herein, the term “number” shall mean one or an integer greater than one (i.e., a plurality).
The operating mechanism 100 includes cam member 102, which is rotatably coupled to the housing 4. The cam member 102 having a profile cooperates with a two-bar linkage member 121 having links such as for example first bar 121′ and second bar 121″. The linkage member 121 is pivotably coupled to the housing 4. The first bar 121′ has a first end disposed adjacent to the housing 4 and a second end disposed adjacent to a pivot pin 123. The second bar 121″ has a first end disposed adjacent to the pivot pin 123 and a second end disposed adjacent to a biasing element 126. The first bar 121′ and second bar 121″ are pivotally connected at the pivot pin 123.
The operating mechanism 100 includes an actuating assembly 140. As shown in
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The operating mechanism 100 further includes the movable contact assembly 120, which includes the aforementioned movable electrical contact 122, and cooperates with the cam member 102 in order to move the movable electrical contact 122 into and out of electrical contact with the stationary electrical contacts 6,8. The movable contact assembly 120 includes at least one biasing element 124, which is structured to bias the movable electrical contact 122 away from the stationary electrical contacts 6,8. In the example described herein, the biasing element 124 comprises an opening spring 124 which is disposed between the housing 4 of the battery disconnect apparatus 2 and the movable electrical contact 122. The movable contact assembly 120 can further include a second biasing element 126. In the example described herein, the second biasing element 126 comprises a compression spring which biases the movable electrical contact 122 against the stationary electrical contacts 6,8 in the closed position (
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Another sensing mechanism (not shown), such as an electrical sensing device or a combination of relays, can be employed to generate a signal when it is needed to open the contacts from the closed position. For example, a sensor (not shown) can be used to detect an arc fault, ground fault or short circuit. Upon detection, a fast opening can be provided by the sensor causing power to be supplied to the solenoid 146 such that the plunger 147 is pushed downward against the two-bar linkage member 121, causing the two-bar linkage member 121 to be pushed beyond its horizontal center point, and allowing the spring then to be engaged to fully open the electrical contacts 6,8,122. As shown from
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Accordingly, the disclosed operating mechanism 100 employs a unique cam member 102, two-bar linkage member 121, movable contact assembly 120, and actuating assembly 140 to provide a relatively small, lightweight and cost-effective mechanism for effectively operating (e.g., opening and closing) the separable contacts 6, 8, 122 of the battery disconnect apparatus 2,2′,2″ while resisting arcing hazards commonly associated with shock and vibration loads experienced by a vehicle.
While specific embodiments of the invention have been described in detail, it will be appreciated by those skilled in the art that various modifications and alternatives to those details could be developed in light of the overall teachings of the disclosure. Accordingly, the particular arrangements disclosed are meant to be illustrative only and not limiting as to the scope of the invention which is to be given the full breadth of the claims appended and any and all equivalents thereof.
Number | Name | Date | Kind |
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3600538 | Puzas et al. | Aug 1971 | A |
5949157 | Hirzel | Sep 1999 | A |
Number | Date | Country | |
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20090314620 A1 | Dec 2009 | US |