The present invention relates to a contactor.

Background Art

An electrical contactor is a switch that is designed to open and close repeatedly to supply and interrupt electrical power to electrical loads, such as motors and the like. A typical electrical contactor consists of two main functional parts: a contact part and an actuation part. The contact part is the load-current carrying part of the electrical contactor, which is made of low-resistance metal, such as copper, silver and gold. Normally, the contact part may keep its original state due to gravity or some other forces (for example, spring pressure). On the other hand, the actuation part may provide the driving force to switch the contact part to its reverse state, and maintain the contact part in the reverse state by counteracting the gravity or other restoring forces (for example, spring force). Typically, the actuation part is energized by inputting electricity. After the electricity is removed, the actuation part is de-energized and the contact part returns to its original state. Therefore, the contact part can repeatedly switch between two different states, to conduct or break power supply to electrical loads by controlling the electricity input to the actuation part.

The most common electrical contactor used in industrial fields is an electromagnetic contactor, which is operated by controlling a small current to open and close the power circuit electromagnetically. Referring to Fig. 1, the electromagnetic contactor 1 may has the following components: an electromagnet (E-Frame) 106, an armature 105, a coil 108, a spring 107, movable contacts 101, 102 and stationary contacts 103, 104. The E-Frame 106, when energized by the coil 108, becomes an electromagnet. The armature 105, which is moveable but is held by a spring 107, is connected to the movable contacts 101, 102. When the coil 108 is energized, the moveable contacts 101, 102 are pulled toward the stationary contacts 103, 104 because the armature 105 is pulled toward the E-frame 106. Once the moveable contacts 101, 102 and the stationary contacts 103, 104 meet, power can flow through the contactor 1 to a load. When the coil 108 is de-energized, the magnetic field is broken, and the spring 107 forces the moveable contacts and the stationary contacts apart.

In the existed electromagnetic contactor, the actuation part is formed by the electromagnet (E-Frame) 106, the armature 105, the coil 108 and the spring 107 and is bulky, and thus the existed electromagnetic contactor is bulky. Summary

Enbodiments of the present invention provide a contactor, which is compact. A contactor according to embodiments of the present invention may comprise: a frame; a first part, having stationary contacts and installed on the frame; a second part, having movable contacts; and an electrostatic actuator, connected to the frame and the second part, wherein the electrostatic actuator includes: an elastic ribbon; and a plurality of electrode plate pairs, each electrode plate pair of which sandwiches the elastic ribbon, wherein the plurality of electrode plate pairs is piled up into a multi-layer structure through folding of the elastic ribbon.

In an implementation, the electrostatic actuator shrinks to hold the movable contacts and the stationary contacts together when opposite charges are applied respectively to opposite electrode plates of adjacent electrode plate pairs of the plurality of electrode plate pairs, and the electrostatic actuator relaxes to keep the movable contacts away the stationary contacts when the opposite charges applied to the opposite electrode plates of the adjacent electrode pairs of the plurality of electrode plate pairs are removed.

In another implementation, the electrostatic actuator expands to hold the movable contacts and the stationary contacts together when identical charges are applied to electrode plates of the plurality of electrode plate pairs, and the electrostatic actuator relaxes to keep the movable contacts away the stationary contacts when the identical charges applied to the electrode plates of the plurality of electrode plate pairs are removed.

In an implementation, the contactormay further comprise: at least two springs located around the electrostatic actuator or one spring within which the electrostatic actuator is located, wherein the at least two springs or the one spring is connected to the frame and the second part.

In an implementation, a gap distance between any two adjacent electrode plate pairs of the plurality of electrode plate pairs is identical.

In an implementation, the elastic ribbon is insulated.

In an implementation, electrode plates of the plurality of electrode plate pairs have the same shape and dimension.

In an implementation, the plurality of electrode plate pairs is parallel to each other.

In an implementation, the elastic ribbon includes active polymer parts and passive polymer parts connected alternately, wherein the elastic ribbon is folded at the active polymer parts and each electrode plate pair of the plurality of electrode plate pairs sandwiches the elastic ribbon on one of the passive polymer parts.

In an implementation, the active polymer parts are polyimide hinges that shrink at a prefined temperature or shape-memory polymer elements that actuate with resistive heating.

In an implementation, a surface of each of electrode plates of the plurality of electrode plate pairs is coated with insulated material.

It can be seen from the above that the contactor according to embodiments of the present invention uses the electrostatic actuator as the actuation part, which is manufactured only through folding of single elastic ribbon and small, so the contactor according to embodiments of the present invention is compact compared to the prior art.

Description of Figures

These and other features and advantages of the present invention will become apparent through the following detailed description in conjunction with accompanying drawings.

Fig.1 shows a diagram of existed electromagnetic contactor.

Fig.2 shows a diagram of a contactor according to an embodiment of the invention.

Fig.3 shows a diagram of an electrostatic actuator according to an embodiment of the present.

Fig.4 shows a diagram of a shrinked contactor according to an embodiment of the invention.

Fig.5 shows a flowchart of a method for manufacturing an electrostatic actuator according to an embodiment of the present.

Fig.6 shows a diagram of coating black ink on active polymer parts according to an embodiment of the present.

Figs.7 A and 7B show a diagram of a contactor according to another embodiment of the invention.

Figs.8 A shows a diagram of a contactor according to a further embodiment of the invention.

Figs.8B shows a diagram of a contactor according to yet another embodiment of the invention. Mode for Carrying Out the Invention

Various embodiments are now described with reference to the drawings, wherein like reference numerals are used to refer to like elements throughout. In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of one or more embodiments. It may be evident, however, that such embidiments can be practiced without these specific details. In other instances, well-known structures and devices are shown in block diagram form in order to facilitate describing one or more embidments.

Fig.2 shows a diagram of a contactor according to an embodiment of the invention. As shown in Fig.2, contactor 10 may include a frame 20, a first part 30, a second part 40, two springs 50 and an electrostatic actuator 60. The first part 30 may have two stationary contacts 302, 304 and is installed on the frame 20.

The second part 40 may have two movable contacts 402, 404 and is movable.

The two springs 50 are located around the electrostatic actuator 60 and are connected with the frame 20 and the second part 40.

The electrostatic actuator 60 is connected with the frame 20 and the second part 40. When charges are applied to the electrostatic actuator 60, electrostatic force is generated in the electrostatic actuator 60, and the generated electrostatic force offsets elastic forces of the two springs 50 and the electrostatic actuator 60 and thus causes the second part 40 to move toward the first part 30 to hold the movable contacts 402, 404 and the stationary contacts 302, 304 together. When the charges applied to the electrostatic actuator 60 are removed, no electrostatic force is generated in the electrostatic actuator 60, and the elastic forces of the two springs 50 and the electrostatic actuator 60 cause the second part 40 to move away from the first part 30 to keep the movable contacts 402, 404 away from the stationary contacts 302, 304.

Fig.3 shows a diagram of an electrostatic actuator according to an embodiment of the present. As shown in Fig.3, the electrostatic actuator 60 may include an insulated elastic ribbon 600 and four electrode plate pairs 610-640.

The insulated elastic ribbon 600 may include three active polymer parts 604 and four passive polymer parts 608 connected alternately. The three active polymer parts 604 may be polyimide hinges that shrink at a predefined temperature or shape memory polymer elements that actuate with resistive heating, and thus the insulated elastic ribbon 600 can fold at the three active polymer parts 604 when the three active polymer parts 604 are heated.

The electrode plate pair 610 may include two electrode plates 612 and 614, the electrode plate pair 620 may include two electrode plates 622 and 624, the electrode plate pair 630 may include two electrode plates 632 and 634, and the electrode plate pair 640 may include two electrode plates 642 and 644. The electrode plates 612, 614, 622, 624, 632, 634, 642 and 644 may be of square and have the same dimension L*L. Each electrode plate pair of the four electrode plate pairs 610-640 sandwiches the insulated elastic ribbon 600 on one of the four passive polymer parts 608.

The four electrode plate pairs 610-640 are piled up into a multi-layer configuration through folding of the insulated elastic ribbon 600 at the three active polymer parts 604. In the multi-layer configuration, the four electrode plate pairs 610-640 may be parallel to each other.

In the multi-layer configuration, there are the same gap distances d between any two adjacent electrode plate pairs, i.e., between the electrode plate pair 610 and the electrode plate pair 620, between the electrode plate pair 620 and the electrode plate pair 630, and between the electrode plate pair 630 and the electrode plate pair 640. In other words, the gap distances d between any two adjacent electrode plate pairs of the four electrode plate pairs 610-640 are identical in the multi-layer configuration. In order to enable the electrostatic actuator 60 to output high electrostatic force, the electrostatic actuator 60 may be designed so that the gap distances d between adjacent electrode plate pairs of the four electrode plate pairs 610-640 are small when the electrostatic actuator 60 relaxes and is in its original state.

In order to enable the electrostatic actuator 60, a charging process is initiated to apply opposite voltages (positive and negative voltages) respectively to opposite electrode plates of adjacent electrode plate pairs of the four electrode plate pairs 610-640. When the opposite voltages are applied to the opposite electrode plates of the adjacent electrode plate pairs of the four electrode plate pairs 610-640, i.e., opposite electrode plates 614 and 622 of the adjacent electrode plate pairs 610 and 620, opposite electrode plates 624 and 632 of the adjacent electrode plate pairs 620 and 630, and opposite electrode plates 634 and 642 of the adjacent electrode plate pairs 630 and 640, positive and negative charges begin to accumulate on the opposite electrode plates of the adjacent electrode plate pairs of the four electrode plate pairs 610-640 respectively. Attractive electrostatic force will be generated between the opposite electrode plates of the adjacent electrode plate pairs of the four electrode plate pairs 610-640 due to the positive and negative charges accumulated on the opposite electrode plates and become larger and larger as more and more charges are accumulated on the opposite electrode plates. The generated attractive electrostatic force offsets spring force of the two springs 50 and the insulated elastic ribbon 600 to reduce the gap distances between adjacent electrode plate pairs of the four electrode plate pairs 610-640 and thus the electrostatic actuator 60 shrinks, which pulls the second part 40 toward the first part 30.

When the electrostatic actuator 60 shrinks to meet the movable contacts 402, 404 and the stationary contacts 302, 304, the charging process is finished and the opposite voltages are removed. In this case, the attractive electrostatic force will still be generated between the opposite electrode plates of the adjacent electrode plate pairs of the four electrode plate pairs 610-640 because of the positive and negative charges accumulated on the opposite electrode plates and thus the electrostatic actuator 60 keeps shrinking to hold the movable contacts 402, 404 and the stationary contacts 302, 304 together, as shown in Fig.4.

When the positive and negative charges accumulated on the opposite electrode plates of the adjacent electrode plate pairs of the four electrode plate pairs 610-640 are removed to disable the electrostatic actuator 60, no attractive electrostatic force is generated between the opposite electrode plates of the adjacent electrode plate pairs of the four electrode plate pairs 610-640, the elastic forces of the two springs 50 and the elastic ribbon 600 extend the gap distances between adjacent electrode plate pairs of the four electrode plate pairs 610-640 and thus the electrostatic actuator 60 relaxes and resume to its original state, which pushes the second part 40 away from the first part 30 to keep the movable contacts 402, 404 away from the stationary contacts 302, 304, as shown in Fig.2. Fig.5 shows a flowchart of method for manufacturing the electrostatic actuator according to an embodiment of the invention. As shown in Fig.5, at Step S510, the four electrode plate pairs 610-640 are installed on the insulated elastic ribbon 600 in a manner that each electrode plate pair of the four electrode plate pairs 610-640 sandwiches the insulated elastic ribbon 600 on one of the four passive polymer parts 608 of the insulated elastic ribbon 600.

At Step S520, black ink is coated on one surface of each of the three active polymer parts 604 of the insulated elastic ribbon 600 so that surfaces with black ink of any two adjacent active polymer parts of the three active polymer parts 604 are opposite surfaces, as shown in Fig.6.

At Step S530, the three active polymer parts 604 of the insulated elastic ribbon 600 are heated for example by placing the insulated elastic ribbon 600 under an infrared light. The surfaces with black ink of the three active polymer parts 604 will heat up faster than the surfaces with no black ink of the three active polymer parts 604 due to the effective light absorption by the black ink, so the insulated elastic ribbon 600 is folded at the three active polymer parts 604 to pile up the four electrode plate pairs 610-640 into the multi-layer configuration.

Clearly from the above description, the electrostatic actuator 60 is manufactured only through folding of single insulated elastic ribbon 600, so the electrostatic actuator 60 can be manufactured easily. Further, the electrostatic actuator 60 manufactured through folding of single insulated elastic ribbon 600 is small, so the contactor 10 is compact. Further, the electrostatic actuator 60 consumes power only during the charging process, but the charging process is very fast, for example, it lasts for roughly 600 microseconds, and therefore the contactor 10 may consume little electrical power when it works.

Other Embodiments

Those skilled in the art will understand that in the above embodiment, the gap distances between any two adjacent electrode plate pairs of the four electrode plate pairs 610-640 in the multi-layer configuration are identical, but the present invention is not so limited. In some other embodiments of the present invention, the gap distances between adjacent electrode plate pairs of the four electrode plate pairs 610-640 may be different.

Those skilled in the art will understand that in the above embodiments, the electrode plates 612, 614, 622, 624, 632, 634, 642 and 644 are of square, but the present invention is not so limited. In some other embodiments of the present invention, the electrode plates 612, 614, 622, 624, 632, 634, 642 and 644 are of other shape.

Those skilled in the art will understand that in the above embodiments, the three active polymer parts 604 of the insulated elastic ribbon 600 are heated by placing the insulated elastic ribbon 600 under an infrared light, but the present invention is not so limited. In some other embodiments of the present invention, the three active polymer parts 604 of the insulated elastic ribbon 600 may be heated by only placing the three active polymer parts 604 under the infrared light.

Those skilled in the art will understand that in the above embodiments, the insulated elastic ribbon 600 include three active polymer parts 604 and four passive polymer parts 608 connected alternately, but the present invention is not so limited. In some other embodiments of the present invention, the insulated elastic ribbon 600 may be made totally from the active polymer parts, the four electrode plate pairs 610-640 are installed on the insulated elastic ribbon 600 at a predefined interval and only these parts of the insulated elastic ribbon 600 between any two adjacent electrode plate pairs of the four electrode plate pairs 610-640 are heated to fold the insulated elastic ribbon 600 when the electrostatic actuator 60 is manufactured.

Those skilled in the art will understand that in the above embodiments, the insulated elastic ribbon 600 is made from the polymer parts which can be heated to fold the insulated elastic ribbon 600, but the present invention is not so limited. In some other embodiments of the present invention, the insulated elastic ribbon 600 is made from an element which can be manipulated by a machine to fold the insulated elastic ribbon 600.

Those skilled in the art will understand that two copper wires may be embedded within the insulated elastic ribbon 600 to apply voltages to the electrode plates 612, 614, 622, 624, 632, 634, 642 and 644, wherein one of the two copper wires is connected to the electrode plates 612, 622, 632 and 642, the other is connected to the electrode plates 614, 624, 634 and 644.

Those skilled in the art will understand that in the above embodiments, the electrode plates 612, 614, 622, 624, 632, 634, 642 and 644 have the same dimension, but the present invention is not so limited. In some other embodiments of the present invention, the electrode plates 612, 614, 622, 624, 632, 634, 642 and 644 may have different dimension.

Those skilled in the art will understand that insulated material may be coated on a surface of each of the electrode plates 612, 614, 622, 624, 632, 634, 642 and 644, to prevent the opposite charges on the opposite electrode plates of the adjacent electrode plate pairs of the four electrode plate pairs 610-640 from being counteracted even if the opposite electrode plates of the adjacent electrode plate pairs of the four electrode plate pairs 610-640 meet.

Those skilled in the art will understand that in the above embodiments, the first part 30 and the second part 40 are arranged such that the movable contacts 402, 404 and the stationary contacts 302, 304 are held together when the electrostatic actuator 60 shrinks, but the present invention is not so limited. In some other embodiments of the present invention, the first part 30 and the second part 40 may be arranged as shown in Fig.7 A and Fig.7B such that the movable contacts 402, 404 and the stationary contacts 302, 304 are held together when the electrostatic actuator 60 expands.

Specifically, during the charging processs, identical voltage (i.e., positive or negative voltage) is applied to electrode plates of the four electrode plate pairs 610-640 in the charging process, and positive or negative charges begin to accumulate on the electrode plates of the four electrode plate pairs 610-640. Repellent electrostatic force will be generated between opposite electrode plates of adjacent electrode plate pairs of the four electrode plate pairs 610-640 due to the positive or negative charges accumulated on the electrode plates and become larger and larger as more and more charges are accumulated on the electrode plates. The repellent electrostatic force offsets elastic force of the two springs 50 and the insulated elastic ribbon 600 to extend the gap distances between adjacent electrode plate pairs of the four electrode plate pairs 610-640 and thus the electrostatic actuator 60 expands, which pushes the second part 40 toward the first part 30.

When the electrostatic actuator 60 expands to meet the movable contacts 402, 404 and the stationary contacts 302, 304, the charging process is finished and the identical voltage is removed. In this case, the repellent electrostatic force will still be generated between the opposite electrode plates of the adjacent electrode plate pairs of the four electrode plate pairs 610-640 because of the positive or negative charges accumulated on the electrode plates and thus the electrostatic actuator 60 keeps expanding to hold the movable contacts 402, 404 and the stationary contacts 302, 304 together, as shown in Fig.7B.

When the positive or negative charges accumulated on the electrode plates of the four electrode plate pairs 610-640 are removed to disable the electrostatic actuator 60, no repellent electrostatic force is generated between the opposite electrode plates of the adjacent electrode plate pairs of the four electrode plate pairs 610-640, the elastic forces of the two springs 50 and the elastic ribbon 600 reduce the gap distances between adjacent electrode plate pairs of the four electrode plate pairs 610-640 and thus the electrostatic actuator 60 relaxes and resume to its original state, which pulls the second part 40 away from the first part 30 to keep the movable contacts 402, 404 away from the stationary contacts 302, 304, as shown in Fig.7A.

Those skilled in the art will understand that in the above embodiments, the electrostatic actuator 60 is formed by pilling up the four electrode plate pairs 210-240 together, but the present invention is not so limited. In some other embodiments of the present invention, the electrostatic actuator 60 may be formed by piling up two, three or more four electrode plate pairs together. It is evident that the more the number of electrode plate pairs for forming the electrostatic actuator 60, the larger the stable travel distance achieved by the electrostatic actuator 60 is.

Those skilled in the art will understand that in the above embodiments, the ribbon 600 is insulated, but the present invention is not so limited. In some other embodiments of the present invention, the ribbon 600 may be not insulated. When the ribbon 600 is not insulated, insulated materials are placed between the ribbon 600 and the electrode plates of the electrode plate pairs so that the electrode plates of the electrode plate pairs do not contact the ribbon 600 directly.

Those skilled in the art will understand that in the above embodiments, the contactor 10 includes the two springs 50 located around the electrostatic actuator 60, but the present invention is not so limited. In some other embodiments of the present invention, the contactor 10 may include more two springs located around the electrostatic actuator 60.

Those skilled in the art will understand that in the above embodiments, the contactor 10 includes the springs located around the electrostatic actuator 60, but the present invention is not so limited. In some other embodiments of the present invention, the contactor 10 may only include one spring within which the electrostatic actuator 60 is located.

Those skilled in the art will understand that in the above embodiments, the contactor 10 includes springs located around the electrostatic actuator 60 or one spring within which the electrostatic actuator 60 is located, but the present invention is not so limited. In some other embodiments of the present invention, the contactor 10 may include no spring, as shown in Fig.8 A and Fig.8B.

Those skilled in the art will understand that various modifications and variations can be made to the above embodiments without departing from the essence of the invention, and the protection scope of the present invention should be defined by the claims appended.