1. Field of the Invention
The invention relates generally to circuit interrupters and, more particularly, to operating mechanisms for 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.
There is a need, therefore, for an improved operating mechanism for 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 battery disconnect apparatus and in operating mechanisms therefor.
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 to resist the separable 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.
As one 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 pivotably coupled to the housing, the cam member having a profile, the profile having a first portion and a second portion; a movable contact assembly comprising a movable electrical contact, the movable contact assembly being structured to cooperate with the cam member in order 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 pivot the cam member between a first position corresponding to the first portion of the profile being 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 corresponding to the second portion of the profile being structured 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 first portion of the profile may have a first radius, and the second portion of the profile may have a second radius, wherein the first radius is greater than the second radius, and wherein the profile comprises a step from the first radius to the second radius. The movable contact assembly may further comprise at least one biasing element structured to bias the movable electrical contact away from the number of stationary electrical contacts. When the cam member is moved from the first position toward the second position, the step of the profile may be structured to enable such biasing element to move the movable contact assembly toward the second portion of the profile, in order to move the movable electrical contact away from the number of stationary electrical contacts. The movable contact assembly may further comprise a movable member, wherein the biasing element is disposed between the movable electrical contact and the movable member and the movable member is disposed between the biasing element and the cam member. The biasing element and the movable member may be structured to resist the movable electrical contact from bouncing with respect to the number of stationary electrical contacts.
The actuating assembly may comprise at least one actuator and a latch. The latch may include a first end and a second end. The latch may be structured to move linearly, or it may include a pivot and be pivotably coupled to the housing. The pivot may be disposed at or about the first end, or between the first end and the second end. When the cam member is disposed in the first position, the first end of the latch may engage the profile at or about the step, thereby preventing the cam member and the movable contact assembly from moving. Such actuator may be structured to move the second end of the latch, thereby pivoting the latch about the pivot in order to disengage the first end of the latch from the profile and to permit the cam member to pivot.
The at least one actuator may comprise a solenoid including a plunger, wherein the plunger is coupled to the latch at or about the second end of the latch, and wherein the solenoid is structured to move the plunger, thereby moving the first end of the latch out of engagement with the profile. The at least one actuator may further comprise a motor, and the actuating assembly may further comprise 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 may have a perimeter, wherein a portion of the perimeter of the cam gear is devoid of the teeth. When the cam member is disposed in the first position, the portion of the perimeter of the cam gear, which is devoid of the teeth, may be structured to disengage the cam gear and the cam member from the number of reduction gears, the drive gear and the motor. When the cam member is disposed in the second position, the teeth of the cam gear may be engagable with the teeth of a corresponding one of the number reduction gears, in order that the motor is movable to move the drive gear, the corresponding one of the number of reduction gears, and the cam gear, thereby moving the first portion of the profile of the cam member into engagement with the movable contact assembly to reset the battery disconnect apparatus.
As another aspect of the invention, a circuit interrupter comprises: a housing; separable contacts enclosed by the housing, the separable contacts including a number of stationary electrical contacts and at least one movable electrical contact; and an operating mechanism comprising: a cam member pivotably coupled to the housing, the cam member having a profile, the profile having a first portion and a second portion, a movable contact assembly cooperable with the cam member in order 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 pivot the cam member between a first position corresponding to the first portion of the profile maintaining the movable electrical contact of the movable contact assembly in electrical contact with the number of stationary electrical contacts, and a second position corresponding to the movable contact assembly being releasable by the second portion of the profile in order that the movable electrical contact is movable out of electrical contact with the number of stationary electrical contacts.
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; 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 a cam member 102 (shown in phantom line drawing in
Referring again to
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 (see, for example,
In the example shown and described herein, a roller 130 is disposed on the end of the movable member 126. The opening spring 124 and a second biasing element 128, which in the example of
The actuating assembly 140 includes at least one actuator 142,144 and a latch 146. The example latch 146 is pivotably coupled to the housing 4 (best shown in
As will be described hereinbelow, movement of the cam member 102 is provided by the combination of a separate, second actuator, which in the example shown and described herein is a motor 144, and a resilient member 154 (e.g., over-center spring). Thus, in the example shown and described herein, the at least one actuator comprises the solenoid 142 and the motor 144, which perform the separate and distinct functions of moving the latch 146 and turning the cam member 102, respectively. More specifically, the solenoid 142 includes a plunger 143, which is coupled to the latch 146 at or about the second end 150 thereof. Accordingly, the solenoid 142 moves the plunger 143, thereby pivoting the latch 146 and moving the first end 148 thereof out of engagement with the cam member profile 104, as previously discussed. It will, however, be appreciated that the solenoid 142 could be employed to move a suitable linear latch (not shown) laterally, as previously discussed.
The actuating assembly 140 further includes at least one resilient member, such as the first and second resilient members 154,156 shown in
The second resilient member 156 of the example actuating assembly 140 includes a first end 162 coupled to the latch 146 proximate the second end 150 of the latch 146, and a second end 164 coupled to the housing 4 of the battery disconnect apparatus 2. Accordingly, it will be appreciated that the second resilient member 156, which in the example shown and described herein is a spring, biases the latch 146 to engage the cam member profile 104 and, in particular, step 114 of the profile 104, as previously discussed (see
In addition to the solenoid 142, the example actuating assembly 140 further includes the aforementioned motor 144, and a plurality of gears 166,168,170,172,174. Among other benefits, the use of the motor 144 and gears 166,168,170,172,174 provide a slower (as compared to a solenoid only) closing speed for the separable contacts 6,8,122, thereby minimizing undesirable bounce of the movable electrical contact 122 with respect to the stationary electrical contacts 6,8 and disadvantageous arcing issues associated therewith. Such disadvantages can occur, for example, in battery disconnect apparatus, which employ solenoids instead of a motor. By way of example, without limitation, one suitable motor 144, which is a DC motor that is relatively low cost, lightweight and vibration and shock resistant in accordance with embodiments of the invention, is the Mabuchi FC-280SC-20150, which is available from Mabuchi Motor Company, Ltd. having a place of business at 430 Matsuhidai, Matsudo City, Chiba, 270-2280 Japan.
The gears 166,168,170,172,174, which will now be discussed, function to decrease the speed of the motor 144 and increase the torque provided thereby. Specifically, the example actuating assembly 140 includes a drive gear 166 coupled to the shaft of the motor 144, a cam gear 174 coupled to the cam member 102, and a number of reduction gears 168,170,172 therebetween. Each of the gears 166,168,170,172,174 has a plurality of teeth 167,169,169′ (FIG. 2),171,171′ (FIG. 2),173,175, which are cooperable in order that all of the gears 166,168,170,172,174 are movable in response to actuation by the motor 144. In this manner, the disclosed gear and motor combination functions to close the separable contacts 6,8,122. By way of a non-limiting example, the aforementioned gear and motor combination functions to turn the cam member 102 at about 43 revolutions per minute (RPM), in order to close the separable contacts 6,8,122 in about 0.7 seconds. It will, however, be appreciated that any known or suitable number and configuration of gears could be employed to provide the desired torque and closing speed.
The cam gear 174, which is best shown in the exploded views of
Specifically, the absence of teeth 175 on portion 178 of the cam gear perimeter 176 permits the cam member 102 to rapidly rotate (e.g., counterclockwise with respect to
Accordingly, the disclosed operating mechanism 100 employs a unique cam member 102, 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 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.
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