The subject matter disclosed herein relates to switching devices for industrial equipment. More specifically, an aspect of the invention relates to switching devices that include a rotary switching mechanism and a system for reducing the torque required to rotate the switch between the Off and On positions.
As is known to those skilled in the art, switching devices are components in an electrical circuit that may be controlled between an “On” state and an “Off” state. In the On state, the switching device establishes an electrical connection between contacts and allows electrical current to flow through the switching device from a power source to an electrical load. In the Off state, the switching device opens, or breaks, the electrical connection between contacts, preventing the electrical current from flowing through the switching device. Switching devices may be used, for example, as a circuit breaker, motor protection device, contactor to supply power to one or more branch circuits, or the like. The switching device may be manually or automatically actuated.
According to one style of manually activated switch, a rotary actuator is provided which rotates between an Off position and an On position. Within the switch, a mechanical linkage is provided which similarly transitions between an Off state and an On state as the rotary actuator is rotated between the Off position and the On position. The rotary actuator includes a handle on a rotary disk, where the rotary actuator is located on an external surface of the switch and is accessible by an operator. When the operator rotates the handle, the rotary actuator engages a mechanical linkage within the switch which allows a plunger to move a switching element within the switching device in a first direction as the switch or actuator transitions from a first state to a second state. The plunger is extended when transitioning from an On state to an Off state, causing separation of electrical contacts and breaking an electrical connection within the switch. A spring exerts a force against the plunger, causing the plunger to retract when transitioning from the Off state back to the On state, allowing the electrical contacts to reconnect and establish an electrical connection within the switch.
Typically, a switch requires actuation in both directions, that is from the Off state to the On state as well as from the On state to the Off state, at the same position within the switch. The mechanical linkage between the rotary actuator and the contacts typically provides a continuous linkage between the rotary actuator and the contacts, such that motion in a first direction will transition between the Off state and the On state at a particular location during the rotation and that motion in a second direction will transition between the On state and the Off state at the same location during the rotation. These continuous mechanical linkages require the force applied to the rotary actuator to move the mechanical linkage between states to be applied generally at the transition point. The rotary actuator, however, is often moved a greater distance, such as over a ninety-degree arc such that a clear indication is provided to an operator whether the switch is in the Off state or the On state. Thus, the entire force required to transition between states is applied over a limited range of rotation of the total travel of the actuator as the switch is toggled between the Off and On states.
Applying the entire force for transitioning between states at a single point in the rotation creates a jerky motion when operating the switch. An operator begins rotation with a light force applied to the actuator. At the transition point, the switch may temporarily stall rotation as the operator increases the force applied. Once the force applied by an operator is sufficient to overcome the mechanical linkage and the internal linkage transitions states, the actuator may jump forward through the rest of the rotation because the required force to travel over the remaining distance is less than the force required at the transition point.
Thus, it would be desirable to provide a mechanical linkage within a switch that provides for smoother operation over an extended range of motion of the actuator.
It would also be desirable to provide a mechanical linkage within a switch that provides a reduced level of torque be applied to the actuator over the extended range of motion, such that the switch provides a more uniform and easier operational feel during actuation.
According to one embodiment of the invention, an apparatus for a switch includes a first rotational member, a second rotational member, and a transfer member. The first rotational member includes a first engagement portion and a first coupling portion. The first engagement portion is configured to receive a force applied to the switch, and the first rotational member moves between a first position and a second position responsive to receiving the force applied to the switch. The second rotational member includes a second coupling portion and a second engagement portion. The second rotational member moves between a third position and a fourth position responsive to receiving the force applied to the switch. The transfer member includes a third coupling portion configured to engage the first coupling portion of the first rotational member and a fourth coupling portion configured to selectively engage the second coupling portion of the second rotational member. The transfer member receives the force applied to the switch from the first rotational member via the third coupling portion and transfers the force applied to the switch to the second rotational member via the fourth coupling portion. The transfer member is configured to move between a fifth position and a sixth position responsive to the first rotational member moving between the first position and the second position.
According to another embodiment of the invention, a method for reducing a force applied to a switch includes applying a first force to a rotary actuator of a switch in a first direction and applying a second force to the rotary actuator of the switch in a second direction. The first force causes the switch to transition between an Off position and an On position, and the second force causes the switch to transition between the On position and the Off position. The first force is applied over a first range of motion of the rotary actuator, and the second force is applied over a second range of motion of the rotary actuator, where the first range of motion is greater than the second range of motion.
According to still another embodiment of the invention, a switching device for industrial equipment having at least one pair of contacts includes a transfer member, a rocker arm, a plunger, and a mechanical linkage. The transfer member is mounted in the switching device, and the transfer member is configured to receive a first force applied to the switching device in a first direction and to receive a second force applied to the switching device in a second direction. The rocker arm is rotatably mounted in the switching device. The rocker arm engages the transfer member to receive the first force over a first angle of rotation, and the rocker arm receives the second force over a second angle of rotation, where the second angle of rotation is less than the first angle of rotation. The plunger is actuated to selectively open and close at least one pair of contacts in the switching device when the switching device is moved between the Off position and the On position. The mechanical linkage is operatively connected between the rocker arm and the plunger. The mechanical linkage engages the plunger to selectively close the at least one pair of contacts as the rocker arm moves over the first angle of rotation, and the mechanical linkage engages the plunger to selectively open the at least one pair of contacts as the rocker arm moves over the second angle of rotation.
These and other advantages and features of the invention will become apparent to those skilled in the art from the detailed description and the accompanying drawings. It should be understood, however, that the detailed description and accompanying drawings, while indicating preferred embodiments of the present invention, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the present invention without departing from the spirit thereof, and the invention includes all such modifications.
Various exemplary embodiments of the subject matter disclosed herein are illustrated in the accompanying drawings in which like reference numerals represent like parts throughout, and in which:
In describing the various embodiments of the invention which are illustrated in the drawings, specific terminology will be resorted to for the sake of clarity. However, it is not intended that the invention be limited to the specific terms so selected and it is understood that each specific term includes all technical equivalents which operate in a similar manner to accomplish a similar purpose. For example, the word “connected,” “attached,” or terms similar thereto are often used. They are not limited to direct connection but include connection through other elements where such connection is recognized as being equivalent by those skilled in the art.
The various features and advantageous details of the subject matter disclosed herein are explained more fully with reference to the non-limiting embodiments described in detail in the following description.
The subject matter disclosed herein describes a mechanical linkage within a switch that provides for smoother operation over an extended range of motion of the actuator. The mechanical linkage includes a transfer member configured to receive the force applied to a rotary handle of the switch. The transfer member is slidably mounted within the switch. In an Off position, the transfer member engages a rocker arm. As the transfer member rotates between the Off and On positions, the transfer member causes the rocker arm to rotate between the Off and On positions. When the rocker arm has reached the On position, the transfer member is slidably moved away from the rocker arm, disengaging the rocker arm. As the rocker arm rotates along with the transfer member between the Off and On positions, the rocker arm engages a mechanical linkage connected between the rocker arm and a plunger. The plunger moves in a first direction and closes the electrical contacts of the switch, causing the switch to transition between the Off and On states.
When the switch is transferred from the On state back to the Off state, a boss engages a slot in the rocker arm. The boss begins applying the rotational force in the opposite direction to the slot in the rocker arm. As the rocker arm begins rotating from the On state to the Off state, the mechanical linkage begins transitioning back to the Off state. After a short period of rotation, the rocker arm and mechanical linkage transition from a stable position to a position in which at least one spring in the switch applies a force to and causes the mechanical linkage to jump back to the Off state. The mechanical linkage returning to the Off state, in turn, causes the rocker arm to also jump back to the Off state. The handle of the switch continues rotating to the Off state. When the handle of the switch reaches the Off state, the transfer member slides back toward the rocker arm and reengages the rocker arm. This combination of transfer member, rocker arm, and mechanical linkage results in a reduced level of torque required to rotate the actuator over the extended range of motion when transitioning from the Off state to the On state. The reduced level of torque, in turn, provides a more uniform and easier operational feel during actuation. The jump back to the Off state provides a quick disconnection of the internal contacts and a reduce force required to rotate the handle back to the Off state.
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The switch 10 also includes a plunger 60 configured to move reciprocally, back-and-forth, along an axis 56. According to the illustrated embodiment shown in
The illustrated plunger 60 is intended to be exemplary only. It is contemplated that multiple plungers 60 may be mechanically connected or formed as a single member to open and close multiple contacts 55 in tandem. It is further contemplated that the geometry of the plunger 60 may take other forms or the plunger 60 may include an offset segment along the length of the plunger such that a force is applied at a first end of the plunger 60 along a first axis and the second end of the plunger 60 moves reciprocally along a second axis where the second axis is parallel to but offset from the first axis.
Although illustrated as a circuit breaker, the rotary actuator 40 and mechanical linkage 50 may be implemented on other switching devices such as a motor protection circuit, an electrical contactor, or the like. Terms such as upper, lower, inner, outer, front, rear, left, right, and the like will be used herein with respect to the illustrated switching device 10. These terms are relational with respect to the illustrated switching device and are not intended to be limiting. It is understood that the switching device 10 may be installed in different orientations, such as vertical or horizontal, or may be rotated one hundred eighty degrees without deviating from the scope of the invention.
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The mechanical linkage 250 also includes the rocker arm 310. The rocker arm 310 includes an opening 315 (see also
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In operation, the transfer member 70 and rocker arm 110 work together to provide a switch 10 that provides for smoother operation over an extended range of motion of the rotary actuator 40. Turning next to
The gear 65 is initially coupled to the transfer member 70 and to the rocker arm 110 while in the Off state, such that rotation of the gear 65 from the Off state to the On state causes rotation of the transfer member 70 and the rocker arm 110. The boss 85, protruding from the second side 73 of the transfer member 70, is inserted in the opening 69 of the gear 65, creating a coupling between the transfer member 70 and the gear 65. Rotation of the gear 65 causes rotation of the transfer member 70. The first boss 72 and the second boss 76, protruding from the first side 71 of the transfer member 70, are each positioned within the slot 120 of the rocker arm 110. As the transfer member 70 begins rotating in response to the rotation of the gear 65, the first boss 72 engages a side of the slot 120, causing rotation of the rocker arm 110.
The transfer member 70 is slidably mounted within the switch 10 such that it may move axially back and forth between the gear 65 and the rocker arm 110. As previously discussed, a mounting pin 57 extends through the gear 65, transfer member 70, and rocker arm 110, providing a common axis of rotation 75 about which each of the three members rotates within the switch. According to the illustrated embodiment, a spring 90 is mounted around the mounting pin 57 and between the gear 65 and the transfer member 70. The spring 90 applies a biasing force on the transfer member 70, axially positioning the transfer member 70 towards the rocker arm 110. It is contemplated that the spring 90 may be mounted, for example, on the boss 85 and between the transfer member 70 and gear 65. Optionally, other types of springs, rather than the illustrated coil spring 90, may be utilized to apply the biasing force on the transfer member 70 without deviating from the scope of the invention. The spring 90 applies a biasing force such that the first boss 72 of the transfer member 70 is initially located within the slot 120 of the rocker arm 110.
As the transfer member 70 rotates, the engagement member 80 of the transfer member 70 contacts a complementary engagement portion of the lever arm 150. More specifically, a tapered engagement surface 81 of the engagement member 80 contacts the first end 152 of the lever arm 150. Continued rotation of the transfer member 70 causes the engagement surface 81 to slide down from the first end 152 and adjacent to the second side 162 of the lever arm 150. The tapered engagement surface 81 allows for some variation in alignment of the transfer member 70 with the first end 152 of the lever arm 150 while still achieving successful engagement between surfaces. The tapered engagement surface 81 also causes the transfer member to compress the spring 90 and slide away from the rocker arm 110 along the axis of rotation 75 as the engagement member 80 rotates down to the second send 162 of the lever arm 150. The transfer member 70 is slidably mounted on the mounting pin 57 and the boss 85 mounted on the second side 73 of the transfer member is slidably mounted within the opening 69 in the gear 65. As the transfer member 70 slides away from the rocker arm 110, the first boss 72 on the first side 71 of the transfer member exits the slot 120 and stops causing further rotation of the rocker arm 110.
During rotation, the rocker arm 110 engages the lever arm 150 which, in turn, allows the contacts 55 on the switch 10 to close. As discussed above, rotation of the transfer member 70 will initially cause rotation of the rocker arm 110 due to the first boss 72 of the transfer member 70 engaging the slot 120 of the rocker arm. As the rocker arm 110 rotates about the axis of rotation 75, the elongated member 130 engages the engagement member 165 of the lever arm 150. The lever arm 150 pivots around the pivotal mount 157. As the second end 154 of the lever arm 150 moves from the Off position to the On position, the plunger 60 is released and the contacts 55 close. The contacts close when the rotary actuator 40 has completed greater than eighty degrees of rotation. Thus, rotation of the rotary actuator 40 in a first direction spreads out actuation of the switch from about twenty to thirty degrees of rotation to over eighty degrees of rotation, while still providing for a quick closure of the contacts 55 due to the spring force applied against the plunger 60. The primary force required by the switch 10 to transition from the Off state to the On state occurs, therefore, over a range of fifty to sixty degrees of rotation in the first direction. In the ON state, the mechanical linkage 50 is in a stable position, allowing the mechanical linkage 50 to remain in the ON state until a second force is applied in the opposite direction.
To turn the switch Off, the second force is applied to the rotary actuator 40 in the opposite direction. As the rotary actuator 40 begins rotating in the opposite direction, the tooth 49 again engages the gap 67 of the gear 65. As illustrated in
As the rocker arm 110 begins rotating from the On position to the Off position, the elongated member 130 of the rocker arm 110 no longer applies a force against the engagement member 165 of the lever arm 150. A spring 200 is mounted to the lower portion 153 of the rocker arm 150 applying a biasing force to the rocker arm 110 toward the Off position. The spring 200 causes the engagement member 165 of the rocker arm 110 to follow the elongated member 130 as the elongated member is rotated away from the rocker arm 110. After the rocker arm 110 and lever arm 150 rotate a short distance, the mechanical linkage 50 passes a stable position, such that additional springs and the corresponding spring forces within the switch 10 cause the lever arm 150 and rocker arm 110 to jump back to the Off state. The jump also causes the lever arm 150 to force the plunger 60 downward, separating the contacts 55 in the switch 10 and putting the switch back in the Off state. This jump occurs when the rotary actuator 40 has reached about the same position at which the contacts 55 close or slightly before the rotary actuator has returned to the eighty degree position. The primary force required by the switch 10 to transition from the On state to the Off state occurs, therefore, over about ten degrees of rotation in the second direction.
As the rotary actuator 40 continues turning back to the full Off position, the gear 65 continues turning the transfer member 70 back to the off position. The first boss 72 of the transfer member 70 is biased against the second side 127 of the body portion 125 of the rocker arm 110 by the spring 90. The first boss 72 slides along the second side 127 until it again reaches the slot 120. The spring 90 forces the transfer member 70 away from the gear 65 and toward the rocker arm 110 causing the first boss 72 to again engage the slot 120 on the rocker arm.
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The transfer member 270 is slidably mounted within the gear 265. In the Off state, the first end 272 of the transfer member 270 engages an interference member 290. The interference member 290 applies a force to the first end 272 of the transfer member 270 that is sufficient to overcome the biasing force from the spring 350 mounted within the elongated channel 269 of the gear 265. The interference member 290 causes the transfer member 270 to slide toward the rocker arm 310, inserting the second end 274 of the transfer member 270 into the recess 340 on the rocker arm. According to the illustrated embodiment, the interference member 290 is a flat spring. The force applied by the flat spring exceeds the force applied by the coil spring 350, causing the transfer member 270 to slide toward the rocker arm 310 and compressing the coil spring 350. Optionally, a rigid member may be utilized for the interference member 290, where the rigid member has an angled form similar to that seen in the top view of
As the gear 265 rotates, the first end 272 of the transfer member 270 rotates along the interference member 290. As seen in
During rotation, the rocker arm 310 engages a further mechanical linkage 360 which, in turn, allows the contacts 55 on the switch 10 to close. As discussed above, rotation of the transfer member 270 will initially cause rotation of the rocker arm 310 due to the transfer member 270 engaging the recess 340 of the rocker arm. As the rocker arm 310 rotates about the axis of rotation 75, the lower portion 330 of the rocker arm 310 pivots around the mounting opening 315. The second opening 337 proximate the lower end of the rocker arm 310 serves as an engagement portion of the rocker arm 310 and is coupled to the additional mechanical linkage 360. Rather than a single lever arm 150, as discussed above with respect to one embodiment of the invention, multiple linkages are pivotally or slidably connected to transfer the force from the rocker arm 310 to the plunger 60. A linking member of the additional mechanical linkage 360 is fixedly, and pivotally mounted within the second opening 337 to serve as an engagement portion of the additional mechanical linkage 360. Rotation of the lower portion 330 of the rocker arm 310 causes one end of the linking member to move right and the other end of the linking member to rotate downward to engage a lever arm, which, in turn, engages the plunger 60. When the rocker arm 310 reaches the On state, the additional mechanical linkage 360 has allowed the plunger 60 to release and the contacts 55 within the switch 10 to close. The contacts close when the rotary actuator 40 has completed greater than eighty degrees of rotation. Thus, rotation of the rotary actuator 40 in a first direction spreads out actuation of the switch from about twenty to thirty degrees of rotation to over eighty degrees of rotation, while still providing for a quick closure of the contacts 55 due to the spring force applied against the plunger 60. The primary force required by the switch 10 to transition from the Off state to the On state occurs, therefore, over a range of fifty to sixty degrees of rotation in the first direction. In the ON state, the mechanical linkage 250 is in a stable position, allowing the mechanical linkage 250 to remain in the ON state until a second force is applied in the opposite direction.
To turn the switch Off, the second force is applied to the rotary actuator 40 in the opposite direction. As the rotary actuator 40 begins rotating in the opposite direction, the tooth 49 again engages the gap 267 of the gear 265. The arcuate boss 280 of the gear 265 is positioned within the arcuate slot 345 of the rocker arm 310. One end of the arcuate boss 280 engages a side wall of the arcuate slot 345, transferring the second force from the gear 265 to the rocker arm 310 to begin rotation of the rocker arm 310 from the On position to the Off position. As the rocker arm 310 begins rotating from the On position to the Off position, the lower portion 330 of the rocker arm 310 pivots away from the additional mechanical linkage 360. Further, because the second opening 337 is coupled to the additional mechanical linkage 360, the rocker arm 310 causes the additional mechanical linkage to begin returning to the Off position. One or more springs connected to the additional mechanical linkage 360 apply a biasing force on the mechanical linkage 360 to return to the Off position. After the gear 367 and rocker arm 310 rotate a short distance, the rocker arm 310 draws the additional mechanical linkage 360 past a stable position, such that the additional springs and the corresponding spring forces within the switch 10 cause the additional mechanical linkage 360 and the rocker arm 310, connected to the additional mechanical linkage, to jump back to the Off state. The jump also forces the plunger 60 downward, separating the contacts 55 in the switch 10 and putting the switch back in the Off state. This jump occurs when the rotary actuator 40 has reached about the same position at which the contacts 55 close or slightly before the rotary actuator has returned to the eighty degree position. The primary force required by the switch 10 to transition from the On state to the Off state occurs, therefore, over about ten degrees of rotation in the second direction.
As the rotary actuator 40 continues turning back to the full Off position, the gear 265 continues turning toward the Off position. The second end 274 of the transfer member 270 slides along the first side 326 of the rocker arm 310. The first end 272 of the transfer member 270 engages the interference member 290 causing compression of the spring 350 in the elongated channel 269. The second end 274 of the transfer member 270 continues to slide along the first side 326 of the rocker arm 310 until the transfer member 270 is again positioned in front of the recess 340 in the rocker arm 310. The second end 374 of the transfer member 270 then slides into the recess 340 on the rocker arm 310 returning the switch to the Off position.
It should be understood that the invention is not limited in its application to the details of construction and arrangements of the components set forth herein. The invention is capable of other embodiments and of being practiced or carried out in various ways. Variations and modifications of the foregoing are within the scope of the present invention. It also being understood that the invention disclosed and defined herein extends to all alternative combinations of two or more of the individual features mentioned or evident from the text and/or drawings. All of these different combinations constitute various alternative aspects of the present invention. The embodiments described herein explain the best modes known for practicing the invention and will enable others skilled in the art to utilize the invention.
In the preceding specification, various embodiments have been described with reference to the accompanying drawings. It will, however, be evident that various modifications and changes may be made thereto, and additional embodiments may be implemented, without departing from the broader scope of the invention as set forth in the claims that follow. The specification and drawings are accordingly to be regarded in an illustrative rather than restrictive sense.
Number | Name | Date | Kind |
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5569894 | Uchida | Oct 1996 | A |
20130118872 | Fleitmann | May 2013 | A1 |
20150235794 | Rakuff | Aug 2015 | A1 |