DESC:BACKGROUND

FIELD OF THE INVENTION

The present invention generally relates to electrical machines, and, more particularly, to a self-engaging and disengaging slotted disc switching device.

DESCRIPTION OF THE RELATED ART

Electrical switching devices are used to ensure safety of electrical equipments. Generally, the electrical switching devices utilize a disc cam and multiple moving and fixed contacts to achieve various switching configurations. The disc cam is fastened to a movable shaft. The movable shaft is actuated by using a motor. The moving contacts are displaced by the rotation of the disc cam. However, the conventional electrical switching devices provide a fixed angular separation between the moving contacts and the moving contacts move at a constant speed. The use of multiple disc cams or interlocking devices consumes space, thereby rendering the electrical switching devices bulky and inefficient. The electrical switching devices use multiple switching mechanisms for multiple configurations. Generally, the switching mechanisms are located inside a housing of a disconnector. Hence, metal particles generated by the electrical switching device are formed inside the housing of the disconnector, thereby resulting in insulation breakdown within the housing of the disconnector.

In light of the foregoing, there exists a need for a self-engaging and disengaging slotted disc switching device that avoids insulation breakdown in the disconnector and reduces the space occupied by the electrical switching device.

OBJECTS OF THE INVENTION

An object of the present invention is to provide a self-engaging and disengaging slotted disc switching device. The self-engaging and disengaging slotted disc switching device includes a first and second cover discs, disc cam, first and second assemblies and first and second links. The first and second cover discs have first and second slots respectively. The first and second cover discs are fixed with respect to an axis passing through centers. The disc cam has third and fourth slots and rotatable about the axis passing through a center. The first and second cover discs are placed on each side of the disc cam. The third and fourth slots are formed on each side of the disc cam. The first assembly is placed between the disc cam and the first cover disc and is engageable with the first and third slots. The second assembly is placed between the disc cam and the second cover disc and is engageable with the second and fourth slots. The first and second links have first and second ends. The first end of the first link is coupled to the first assembly the first end of the second link is coupled to the second assembly. The first and second links are movable along with the rotation of the disc cam when the first and second assemblies are engaged with third and fourth slots, respectively. The first and second links remain stationary when the first and second assemblies are engaged with the first and second slots, respectively.

Another object of the present invention is to provide a switching system for switching two links between first, second, and neutral states by way of a single mechanism.

Yet another object of the present invention is to provide a self-engaging and disengaging slotted disc switching device that avoids insulation breakdown in the disconnector and reduces the space occupied by the electrical switching device.

BRIEF DESCRIPTION OF DRAWINGS

The features of the present invention, which are believed to be novel, are set forth with particularity in the appended claims. Embodiments of the present invention will hereinafter be described in conjunction with the appended drawings provided to illustrate and not to limit the scope of the claims, wherein like designations denote like elements, and in which:

FIGS. 1A-1C show isometric views of an electrical machine in accordance with an embodiment of the present invention; and

FIGS. 1D-1H show side views of the electrical machine in accordance with an embodiment of the present invention.

DETAILED DESCRIPTION OF EMBODIMENTS

As used in the specification, the singular forms “a”, “an” and “the” include plural references unless the context clearly dictates otherwise. For example, the term “an article” may include a plurality of articles unless the context clearly dictates otherwise.

Those with ordinary skill in the art will appreciate that the elements in the Figures are illustrated for simplicity and clarity and are not necessarily drawn to scale. For example, the dimensions of some of the elements in the Figures may be exaggerated, relative to other elements, in order to improve the understanding of the present invention.

There may be additional components described in the foregoing application that are not depicted on one of the described drawings. In the event such a component is described, but not depicted in a drawing, the absence of such a drawing should not be considered as an omission of such design from the specification.

Before describing the present invention in detail, it should be observed that the present invention utilizes a combination of system components to provide a self-engaging and disengaging slotted disc switching device. Accordingly, the components and the method steps have been represented, showing only specific details that are pertinent for an understanding of the present invention so as not to obscure the disclosure with details that will be readily apparent to those with ordinary skill in the art having the benefit of the description herein.

As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention, which can be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present invention in virtually any appropriately detailed structure. Further, the terms and phrases used herein are not intended to be limiting but rather to provide an understandable description of the invention.

Referring together to FIGS. 1A, 1B, and 1C, isometric views of an electrical machine 100, in accordance with an embodiment of the present invention is shown. The electrical machine 100 includes first and second cover discs 102 and 104, first and second assemblies, first and second moving contacts 106 and 108, and a disc cam 110. The first and second cover discs 102 and 104 are fixed with respect to an axis passing through centers. The disc cam 110 is rotatable with respect to the axis passing through a center. The first and second cover discs 102 and 104 are positioned on each side of the disc cam 110. The disc cam 110 is actuated by using an external drive (not shown). In an embodiment, the disc cam 110 is actuated by a motor. The disc cam 110 may also be actuated by using any other suitable mechanism, such as a mechanical actuator, a servo motor, a hydraulic actuator, a pneumatic actuator, an electromechanical actuator, and the like.

The first cover disc 102 has a first slot 112 and the second cover disc 104 has a second slot 114. The disc cam 110 has third and fourth slots 128 and 130 on each side. The first assembly includes a first pin 118 and a first roller 120. In an embodiment, the pin 118 is of cylindrical shape. However, any shape of pin may be used according to the requirements. The first assembly is placed between the first cover disc 102 and the disc cam 110. The first assembly can be selectively engaged with first and third slots 112 and 128. The second assembly includes a second pin 124 and a second roller 126. The second assembly is placed between the second cover disc 102 and the disc cam 110. The second assembly can be selectively engaged with second and fourth slots 114 and 130.

The first moving contact 106 and the second moving contact 108 have first and second ends. The electrical machine 100 further includes first and second links 116 and 122. The first link 116 has first and second ends. The first end of the first link 116 is connected to the first assembly which includes the first pin 118 and the first roller 120. The second end of the first link 116 is connected to the first end of the first moving contact 106. The second link 122 has first and second ends. The first end of the first second link 122 is connected to the second assembly which includes the second pin 124 and the second roller 126. The second end of the second link 122 is connected to the first end of the second moving contact 108.

Each of the first, second, third, and fourth slots 112, 114, 128, and 130 has keyhole like profile at one end. Each keyhole profile helps in selective engagement and dis-engagement of one of the first and second assemblies to the first, second, third, and fourth slots 112, 114, 128, and 130. The keyhole profile is hereinafter referred to as keyhole. The first, second, third, and fourth slots 112, 114, 128, and 130 have first, second, third, and fourth keyholes 132,134,133, and 135 at one end.

The electrical machine 100 is housed in a gas filled enclosure 140. In an embodiment, the gas is sulfur hexafluoride (SF6). A first end of a first fixed contact 136 is connected to a conductor that carries electricity. A first end of a second fixed contact 138 is connected to a flange of the gas filled enclosure 140. The second end of the first moving contact 106 is connectable to a second end of the first fixed contact 136. The second end of the second moving contact 108 is connectable to a second end of the second fixed contact 138. In an embodiment, the first fixed contact 136 is a disconnector contact and the second fixed contact 138 is an earthing contact. The applications of the gas filled enclosure 140 with the electrical machine 100 is used in switch gears.

The electrical machine 100 is in a first state when the first moving contact 106 is connected to the first fixed contact 136. In the first state, the first pin 118 is in the third keyhole 133 of the third slot 128 of the disc cam 110. When the disc cam 110 rotates in a first direction, the first pin 118 which is engaged in the third keyhole 133 also rotates. The first pin 118 moves through the first slot 112 of the first cover disc 102. When the first pin 118 moves through the first slot 112, the first link 116 attached to the first pin 118 also moves along with the first pin 118. The motion of first link 116 results in linear motion of the first moving contact 106 in the direction of rotation. The first pin 118 is disengaged from the disc cam 110 when the first pin 118 enters the first keyhole 132 of the first slot 112. When the first pin 118 is disengaged from the disc cam 110, the first pin 118 is received in the first keyhole 132 of the first slot 112, thereby facilitating the rotational motion of the disc cam 110. Hence, the first moving contact 106 is disconnected from the first fixed contact 136, thereby transitioning in to a neutral state of the electrical machine 100. The first and second rollers 120 and 126 are used to reduce friction between the first and second pins 118 and 124 and the first and second slots 112 and 114, respectively.

The second link 122 and the second moving contact 108 remain stationary when the first link 116 and the first moving contact 106 are in motion since the second pin 124 is in the second keyhole 134. After the electrical machine 100 achieves the neutral position, the second pin 124 enters the fourth keyhole 135. The fourth keyhole 135 allows the second pin 124 moves through the second slot 114 when the disc cam 110 rotates in the first direction. When the second pin 124 moves through the second slot 114, the second link 122 moves accordingly, thereby causing a linear motion of the second moving contact 108. Therefore, the second moving contact 108 is connected to a second fixed contact 138 as shown in FIG. 1F. The connection of the second moving contact 108 with the second fixed contact 138 is referred to as a second state of the electrical machine 100. The first link 122 and the first moving contact 106 remain stationary when the second link 122 and the second moving contact 108 are in motion since the first pin 118 is in the first keyhole 132.

Referring now to FIG. 1D, the first state of the electrical machine 100 is illustrated. When the electrical machine 100 is in the first state, the first moving contact 106 is connected to the first fixed contact 136.

Referring now to FIG. 1E, the neutral state of the electrical machine 100 is illustrated. When the electrical machine 100 is in the neutral state, neither of the first and the second moving contacts 106 and 108 are connected to the first and second fixed contacts 136 and 138, respectively.

Referring now to FIG. 1F, the second state of the electrical machine 100 is illustrated. When the electrical machine 100 is in the second state, the second moving contact 108 is connected to the second fixed contact 138.

Referring now to FIG. 1G, the disengaging of the first pin 118 from the first slot 112 and engaging of the first pin 118 to the third slot 128 is illustrated.

Referring now to FIG. 1H, the disengaging of the second pin 124 from the second slot 114 and engaging of the second pin 124 to the fourth slot 130 is illustrated.

The electrical machine 100 transitions from the second state to the neutral state when the disc cam 110 rotates in a second direction which is opposite to the first direction. Further, when the disc cam 110 further rotates in the second direction, the electrical machine 100 transitions from the neutral state to the first state. In an embodiment, the first state is a disconnecting state and the second state is an earthing state. In an embodiment, the electrical machine 100 is a slotted switching device for a switch gear.

Hence, the electrical machine 100 is a self-engaging and disengaging switching device. The third and fourth slots 128 and 130 provide a self-interlocking mechanism. The electrical machine 100 provides switching between the first, second, and neutral states by way of a single mechanism, thereby eliminating use of multiple switching systems for the same and increasing efficiency of the electrical machine 100. Further, the angular speed of the motor is configurable for the first, second, and neutral positions, thereby providing varying speeds for multiple switching operations. Further, the electrical machine 100 is located outside an electrical disconnector. Hence, metal particles generated by the electrical machine 100 due to friction between internal components of the electrical machine 100 remain outside an enclosure of the disconnector, thereby avoiding an insulation breakdown within the disconnector.

The present invention has been described herein with reference to a particular embodiment for a particular application. Although selected embodiments have been illustrated and described in detail, it may be understood that various substitutions and alterations are possible. Those having ordinary skill in the art and access to the present teachings may recognize additional various substitutions and alterations are also possible without departing from the spirit and scope of the present invention.

,CLAIMS:1. A slotted switching device comprising:

a first cover disc having a first slot, wherein the first cover disc is fixed with respect to an axis passing through a center thereof;

a second cover disc having a second slot, wherein the second cover disc is fixed with respect to the axis passing through a center thereof;

a disc cam having third and fourth slots and rotatable about the axis passing through a center thereof, wherein the third and fourth slots are formed on each side of the disc cam, and wherein the first and second cover discs are placed on each side of the disc cam;

first and second assemblies, wherein the first assembly is placed between the disc cam and the first cover disc and is engageable with the first and third slots, wherein the second assembly is placed between the disc cam and the second cover disc and is engageable with the second and fourth slots; and

first and second links having first and second ends, wherein the first end of the first link is coupled to the first assembly, wherein the first end of the second link is coupled to the second assembly, wherein the first and second links are movable along with the rotation of the disc cam when the first and second assemblies are engaged with third and fourth slots, respectively, and wherein the first and second links are stationary when the first and second assemblies are engaged with the first and second slots, respectively.

2. The slotted switching device of claim 1, wherein the first assembly includes a first pin and a first roller, wherein the second assembly includes a second pin and a second roller, and wherein the first and second rollers are positioned over the first and second pins, respectively.

3. The slotted switching device of claim 1, further comprising first and second moving contacts, wherein the first and second moving contacts are connected to the second ends of the first and second links respectively.

4. The slotted switching device of claim 1, wherein the first, second, third, and fourth slots have first, second, third, and fourth key holes formed at one end thereof, respectively, and wherein the first, second, third, and fourth key holes facilitate selective engagement and disengagement of the first assembly with the first and third slots, and second assembly with the second and fourth slots.

5. A slotted switching assembly for a switch gear, the slotted switching assembly comprising:

a gas filled enclosure containing an insulating gas and a slotted switching device, wherein the slotted switching device comprises:

a first cover disc having a first slot, wherein the first cover disc is fixed with respect to an axis passing through a center thereof, and wherein the first slot has a first key hole on one side thereof;

a second cover disc having a second slot, wherein the second cover disc is fixed with respect to the axis passing through a center thereof, and wherein the second slot has a second key hole on one side thereof;

a disc cam having third and fourth slots and rotatable about the axis passing through a center thereof, wherein the third and fourth slots are formed on each side of the disc cam, wherein the first and second cover discs are placed on each side of the disc cam, and wherein the third and fourth slots have third and fourth key holes, respectively, on one side thereof;

first and second assemblies, wherein the first assembly is placed between the disc cam and the first cover disc and is engageable with the first and third slots, and wherein the second assembly is placed between the disc cam and the second cover disc and is engageable with the second and fourth slots; and

first and second links having first and second ends, wherein the first end of the first link is coupled to the first assembly, and wherein the first end of the second link is coupled to the second assembly;

first and second fixed contacts, wherein the first fixed contact is connected to a conductor, wherein the second fixed contact is connected to the gas filled enclosure; and

first and second moving contacts having first and second ends, wherein the first ends of the first and second moving contacts are connected to the second ends of the first and second links, respectively, wherein the second ends of the first and second moving contacts are connectable to the first and second fixed contacts, and when the disc cam rotates, the first assembly moves along the first and third slots and the second assembly moves along the second and fourth slots, thereby disengaging the first moving contact from the first fixed contact and engaging the second moving contact to the second fixed contact.

6. The slotted switching assembly of claim 5, wherein the first assembly includes a first pin and a first roller, wherein the second assembly includes a second pin and a second roller, and wherein the first and second rollers are positioned over the first and second pins, respectively.

7. The slotted switching assembly of claim 5, wherein the slotted switching device is in a first state when the first moving contact is engaged to the first fixed contact and the second moving contact is disengaged from the second fixed contact, wherein the slotted switching device is in a second state when the first moving contact is disengaged from the first fixed contact and the second moving contact is disengaged from the second fixed contact, and wherein the slotted switching device is in a third state when the first moving contact is disengaged from the first fixed contact and the second moving contact is engaged to the second fixed contact.

8. The slotted switching assembly of claim 5, wherein the first fixed contact is a disconnector contact, and wherein the second fixed contact is an earthing contact.