Claims:1. An isolation assembly for isolating at least one of automatic dropping device (ADD) and maximum extension device (MED), the isolation assembly comprising:
a pneumatic control unit configured with a pantograph through a first port, a second port, and a third port, the pneumatic control unit comprising:
a main valve configured to allow passing of an air stream towards an air actuator of the pantograph through the first port;
a first isolation valve configured with the main valve, wherein on actuation, the first isolation valve allows passing of a portion of the air stream towards a second isolation valve of the pantograph through a second port; and
a pressure sensor configured with the pantograph through the third port to sensor pressure of the air stream in the third port,
wherein the first isolation valve is actuated based on the sensed pressure,
the pantograph comprising:
the at least one of ADD and MED;
the second isolation valve configured with the pressure sensor through the third port and the at least one of ADD and MED, wherein the second isolation valve is actuated when the portion of air stream coming through the second port exerts a pressure of predetermined amount on the second isolation valve; and
an air actuator configured with the second isolation valve and configured to allow movement of the pantograph between a raised position and a lowered position when the air stream flows through the air actuator.

2. The isolation assembly as claimed in claim 1, wherein, on actuation, the second isolation valve does not allow the flow of air stream towards the carbon strips and the pressure sensor.
3. The isolation assembly as claimed in claim 1, wherein the pantograph comprises a carbon strip configured with the second isolation valve to receive the air stream from the second isolation valve.
4. The isolation assembly as claimed in claim 1, wherein the at least one of the main valve and first isolation valve are actuated by a set of electrical signals received from a train control monitoring system (TCMS).
5. The isolation assembly as claimed in claim 1, wherein the at least one of ADD and MED comprises an ADD, and wherein the ADD is activated and allows lowering of the pantograph, when carbon strips of pantograph are broken.
6. The isolation assembly as claimed in claim 1, wherein the at least one of ADD and MED comprises an MED, and wherein the MED is activated and allows to limit height of the pantograph to a particular vale, when the height of the pantograph reaches a threshold value.
7. The isolation assembly as claimed in claim 1, wherein the at least one of ADD and MED comprises an ADD, and wherein one terminal of the ADD is configured with the air actuator to receive the air stream from the air actuator and second terminal of the ADD is configured with second isolation valve to supply the air stream to the second isolation valve.
8. The isolation assembly as claimed in claim 1, wherein the at least one of ADD and MED comprises an MED, and wherein one terminal of MED is connected to the pressure sensor through the third port, and the second isolation valve.
9. The isolation assembly as claimed in claim 1, wherein the pneumatic control unit comprises an air flow regulator to control a flow rate of air stream before passing through the first port to the pantograph.

10. The isolation assembly as claimed in claim 1, wherein the pneumatic control unit comprises a filter configured to filter the air stream received from the main valve and the filtered air stream is supplied through the first port to the pantograph.
, Description:TECHNICAL FIELD
[0001] The present disclosure generally relates to pantographs used in locomotive and metro systems. More particularly, it pertains to an isolation assembly for isolating at least one of the automatic dropping device (ADD) and maximum extension device (MED) configured in the pantograph.

BACKGROUND
[0002] Background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
[0003] An overhead supply system plays an important role for a locomotive and metro system. The overhead line is called as a catenary system. The power is transferred from the catenary system to the power unit of the locomotive via a pantograph of the locomotive. The pantograph is a device mounted on the roof of the locomotive. It unfolds and extends along a vertical axis. The pantograph collects power through an overhead wire and sends it to the power unit of the locomotive. The pantograph includes a base frame mounted on the supporting insulators of the pantograph. The pantograph also includes an upper arm and a lower arm, where the lower arm pivots against the base frame configured at the roof of the locomotive and is attached to the upper arm. The upper arm is coupled to the carbon strips that act as the current collector.
[0004] In the pantograph system, automatic dropping device (ADD) and maximum extension device (MED) play a significant role in safeguarding the pantograph. In case when the carbon strips are broken, the ADD protects the pantograph by bringing the pantograph to rest position. Further, in absence of catenary, MED protects the pantograph from exceeding a particular height. In other words, the MED limits the height of the pantograph to a particular threshold. When any of MED and ADD is activated, the pantograph is brought into a rest position.
[0005] In some cases, the locomotive may need continuous movement or the pantograph may need to be in raised position even after activation of any of MED and ADD. However, the activation of ADD & MED would not allow the continuous movement of the locomotive and maintain the pantograph in the raised position.
[0006] Therefore, there is a need in the art, for an easy to implement, cost-effective and efficient system that can overcome the above-mentioned problems in the art.

OBJECTS OF THE INVENTION
[0007] A general object of the present disclosure is to provide an isolation assembly that isolates the ADD and MED to allow continuous movement of the locomotive or to continuously maintain the pantograph in raised position.
[0008] An object of the present disclosure is to provide an isolation assembly that allows the pantograph to raise even in case of the carbon strips being broken.
[0009] An object of the present disclosure is to provide an isolation assembly that allows the pantograph to raise even in case of the MED valve is activated.
[0010] An object of the present disclosure is to provide an isolation assembly that is provided with isolation valves configured in the pantograph as well as in the pneumatic control unit.
[0011] An object of the present disclosure is to provide a simple and cost-effective isolation assembly.

SUMMARY
[0012] The present disclosure generally relates to pantographs used in locomotive and metro systems. More particularly, it pertains to an isolation assembly for isolating at least one of automatic dropping device (ADD) and maximum extension device (MED) configured in the pantograph.
[0013] In an aspect, the present disclosure provides an isolation assembly for isolating at least one of automatic dropping device (ADD) and maximum extension device (MED). The isolation assembly includes a pneumatic control unit configured with a pantograph through a first port, a second port, and a third port. The pneumatic control unit includes a main valve configured to allow passing of an air stream towards an air actuator of pantograph through the first port; a first isolation valve configured with the main valve, wherein on actuation, the first isolation valve allows passing of a portion of the air stream towards a second isolation valve of the pantograph through a second port; and a pressure sensor configured with the pantograph through the third port to sensor pressure of the air stream in the third port, wherein the first isolation valve is actuated based on the sensed pressure. The pantograph includes the at least one of ADD and MED; the second isolation valve configured with the pressure sensor through the third port and the at least one of ADD and MED, wherein the second isolation valve is actuated when the portion of air stream coming through the second port exerts a pressure of predetermined amount on the second isolation valve; and an air actuator configured with the second isolation valve and configured to allow movement of pantograph between a raised position and a lowered position when the air stream flows through the air actuator.
[0014] In an embodiment, on actuation, the second isolation valve does not allow the flow of air stream towards the carbon strips and the pressure sensor.
[0015] In an embodiment, the pantograph comprises a carbon strip configured with the second isolation valve to receive the air stream from the second isolation valve.
[0016] In an embodiment, the at least one of the main valve and first isolation valve are actuated by a set of electrical signals received from a TCMS.
[0017] In an embodiment, the at least one of ADD and MED comprises an ADD, and wherein the ADD is activated and allows lowering of the pantograph, when carbon strips of pantograph are broken.
[0018] In an embodiment, the at least one of ADD and MED comprises an MED, and wherein the MED is activated and allows to limit height of the pantograph to a particular vale, when the height of the pantograph reaches a threshold value.
[0019] In an embodiment, the at least one of ADD and MED comprises an ADD, and wherein one terminal of the ADD is configured with the air actuator to receive the air stream from the air actuator and second terminal of the ADD is configured with second isolation valve to supply the air stream to the second isolation valve.
[0020] In an embodiment, the at least one of ADD and MED comprises an MED, and wherein one terminal of MED is connected to the pressure sensor through the third port, and the same terminal of MED is also connected to the second isolation valve.
[0021] In an embodiment, the pneumatic control unit comprises an air flow regulator to control a flow rate of air stream before passing through the first port to the pantograph.
[0022] In an embodiment, the pneumatic control unit comprises a filter configured to filter the air stream received from the main valve and the filtered air stream is supplied through the first port to the pantograph.
[0023] Various objects, features, aspects and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like components.

BRIEF DESCRIPTION OF DRAWINGS
[0024] The accompanying drawings are included to provide a further understanding of the present disclosure, and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure.
[0025] In the figures, similar components and/or features may have the same reference label. Further, various components of the same type may be distinguished by following the reference label with a second label that distinguishes among the similar components. If only the first reference label is used in the specification, the description is applicable to any one of the similar components having the same first reference label irrespective of the second reference label.
[0026] FIG. 1 illustrates an exemplary representation of an isolation assembly, in accordance with embodiments of the present disclosure.
[0027] FIG. 2 illustrates an exemplary representation of an isolation assembly when the main valve is actuated and the isolation valve is not actuated, in accordance with embodiments of the present disclosure.
[0028] FIG. 3 illustrates an exemplary representation of isolation assembly when the main valve is actuated and isolation valve is actuated, in accordance with embodiments of the present disclosure.
[0029] FIG. 4A illustrates an exemplary representation of the pneumatic control unit along with the first isolation valve, in accordance with embodiments of the present disclosure.
[0030] FIG. 4B illustrates an exemplary representation of the pantograph along with the second isolation valve, in accordance with embodiment of the present disclosure.

DETAILED DESCRIPTION
[0031] The following is a detailed description of embodiments of the disclosure depicted in the accompanying drawings. The embodiments are in such detail as to clearly communicate the disclosure. However, the amount of detail offered is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure as defined by the appended claims.
[0032] As used in the description herein and throughout the claims that follow, the meaning of “a,” “an,” and “the” includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise.
[0033] All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g. “such as”) provided with respect to certain embodiments herein is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention otherwise claimed. No language in the specification should be construed as indicating any non-claimed element essential to the practice of the invention.
[0034] Groupings of alternative elements or embodiments of the invention disclosed herein are not to be construed as limitations. Each group member can be referred to and claimed individually or in any combination with other members of the group or other elements found herein. One or more members of a group can be included in, or deleted from, a group for reasons of convenience and/or patentability. When any such inclusion or deletion occurs, the specification is herein deemed to contain the group as modified thus fulfilling the written description of all groups used in the appended claims.
[0035] Exemplary embodiments will now be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments are shown. This disclosure may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. These embodiments are provided so that this disclosure will be thorough and complete and will fully convey the scope of the disclosure to those of ordinary skill in the art. Moreover, all statements herein reciting embodiments of the disclosure, as well as specific examples thereof, are intended to encompass both structural and functional equivalents thereof. Additionally, it is intended that such equivalents include both currently known equivalents as well as equivalents developed in the future (i.e., any elements developed that perform the same function, regardless of structure).
[0036] Various objects, features, aspects and advantages of the present disclosure will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like features.
[0037] Embodiments explained herein relate to an isolation assembly for continuously maintaining the pantograph in the raised position. In the pantograph, ADD and MED are configured to safeguard the pantograph. The ADD protects the pantograph by bringing the pantograph in the rest position in case of carbon strip is broken, whereas the MED protects the pantograph in the absence of a catenary. Due to activation of any of ADD and MED, the pantograph would move in the rest position. However, to continuously maintain a pantograph in the raised position, the activated devices such as ADD or MED need to be isolated. Thus, the proposed isolation assembly continuously maintains the pantograph in the raised position by isolating devices such as ADD or MED.
[0038] FIG. 1 illustrates an exemplary representation of an isolation assembly, in accordance with embodiments of the present disclosure. As illustrated in FIG. 1, the isolation assembly 100 for isolating at least one of automatic dropping device (ADD) and maximum extension device (MED), may include a pneumatic control unit 101 and a pantograph 111. In an exemplary embodiment, the pneumatic control unit 101 may be implemented as a part of the PCU unit of the locomotive. The pneumatic control unit 101 may be configured with a pantograph 111 through a first port 104-1, a second port 104-2, and a third port 104-3 (collectively referred to as ports 104 and individually referred to as port 104). The pneumatic control unit 101 may include a main valve 105 configured to allow passing of an air stream towards an air actuator 113 of pantograph through the first port. The air stream from the first port flows through the third port. Before energizing the main valve 105, the dry air coming from the compressor reaches port 1 and then to the main valve 105. In an exemplary embodiment, the air stream is free from dirt and dry. In a preferred embodiment, the air pressure may be in the range of 6 to 10 bar pressure for the proper function of the Pantograph.
[0039] In an embodiment, during the raising of the pantograph, the main valve 105 may get activated/energized/actuated. In an embodiment, the main valve 105 is 3/2 directional control valve. It is used to trigger the air supply to admit or discharge from the air actuator through electrical signals. A continuous electrical signal of 110 V DC may be supplied to actuate the main valve. Once the electrical signal is removed, the main valve is moved in a non-activated or non-actuated state. The isolation assembly may include a control unit, as a part of train control monitoring system (TCMS), which may generate the electrical signals and send them to the main valve 105 for actuation.
[0040] In an embodiment, when the air stream reaches to a pressure sensor 106 that gives the pressure of the air stream as a feedback to the TCMS. The isolation assembly may include a filter 107 configured with the main valve to receive the air stream from the main valve, and an air flow regulator 109 configured with the filter to receive the air stream from the filter. The filter 107 may filter the air stream, whereas the air flow regulator 109 may control pressure of air stream coming from the filter 107 before passing through the pantograph. The pneumatic control unit 101 may include air flow limiter raising 102-1 and air flow limiter lowering 102-2 (collectively referred to as air flow limiter 102) to increase or decrease the flow rate of the air stream, respectively. The air flow limiter raising 102-1 may be configured on one side of the air flow regulator 109, whereas the air flow limiter lowering 102-2 may be configured on another side of the air flow regulator 109 as shown in FIGs. 1-3.
[0041] In an embodiment, the pneumatic control unit 101 may include a first isolation valve 108 configured with the main valve 105. Upon actuation, the first isolation valve 105 allows passing of a portion of the air stream towards a second isolation valve 114 of the pantograph 111 through a second port 104-2. In an embodiment, the first isolation valve 108 may be configured to be actuated when the at least one of ADD and MED is activated and the pantograph is required to be maintained in the raised position. The configuration of the first isolation valve 108 is similar to the main valve 105. In particular, the first isolation valve is 3/2 directional control valve. The first isolation valve 108 is used to isolate the ADD and MED without affecting the pantograph raising operation through electrical signals. A continuous electrical signal of 110 V DC may be supplied to actuate the main valve. Once the electrical signal is removed, the first isolation valve is moved in a non-activated or non-actuated state. The TCMS may generate the electrical signals and send them to the first isolation valve for actuation.
[0042] In an embodiment, the pneumatic control unit 101 may include a pressure sensor 110 configured with the pantograph through the third port to sensor pressure of the air stream in the third port 104-3. The sensed pressure signal may be sent to the TCMS. The TCMS may inform the user about the sensed pressure. The user may then send electrical signals to the first isolation valve for actuation. Thus, the first isolation valve is actuated based on the sensed pressure.
[0043] In an embodiment, the pantograph may include at least one of ADD and MED, where the ADD 115 protects the pantograph by bringing the pantograph in the rest position in case of broken carbon strip. In particular, in case of broken carbon strip, the air stream gets leaked into the atmosphere and a change in the flow of the air stream is sensed by the ADD and the ADD gets activated. The activation of ADD allows lowering of the pantograph. Further, when the pantograph crosses a particular height limit, the MED gets activated. In particular, the lower arm of the pantograph is connected to the terminal of MED. When the pantograph attains a particular height, the lower arm of the pantograph moves the lever of MED and thus actuates the MED. The MED 116 protects the pantograph in the absence of a catenary by limiting the height of the pantograph to a static position.
[0044] In an embodiment, one terminal of the ADD 115 may be configured with the air actuator 113 and another terminal of the ADD 115 may be configured with a second isolation valve. As shown in FIG. 2, the terminal of ADD connected to the air actuator may receive the air stream from the air actuator 113, whereas the other terminal of the ADD 115 configured with a second isolation valve may supply the received air stream to the second isolation valve 114. In case when the MED is configured in the pantograph, one terminal of MED is connected to the pressure sensor through the third port 104-2, and the same terminal of MED is also connected to the second isolation valve.
[0045] In an embodiment, the pantograph 111 may include the second isolation valve 114 configured with the pressure sensor 110 through the third port 104-3 and the at least one of ADD and MED. The second isolation is actuated based on mechanical triggers. When the second isolation valve is not actuated, the second isolation valve allows flow of air stream from the first port 104-1 towards the third port 104-3. The second isolation valve is actuated when the portion of air stream coming through the second port exerts a pressure of predetermined amount on the second isolation valve. Upon actuation, the second isolation valve does not allow the flow of air stream towards the third port 104-3. Thus, the second isolation valve isolates the MED as shown in FIG. 3.
[0046] In an embodiment, when the second isolation valve is not actuated, the air stream flows from the ADD valve to the carbon strips directly through a direct connection (not shown in figures) between the ADD valve and the carbon strips. When there is a breakage of carbon strip, the pressure of the air stream across the ADD valve changes and as a result, the function of the ADD valve is suppressed. When the second isolation valve is actuated, the air stream does not flow from the ADD valve to the carbon strips. In this manner the second isolation valve isolates the ADD.
[0047] In an embodiment, the pantograph 111 may also include the air actuator 113 configured with the second isolation valve 114 and configured to allow movement of the pantograph between a raised position and a lowered position when the air stream flows through the air actuator 113. The raised position corresponds to a position when the upper arm of the pantograph moves in upward direction against a lower arm of the pantograph, whereas the lowered position corresponds to a position when the upper arm moves in downward direction towards the lower arm. In particular, when the air actuator 113 such as bellow receives sufficient air stream, the pantograph gets extended and moves from the lowered position to the raised position. Upon actuation of the second isolation valve, the air still flows through the air actuators, thus allowing the pantograph to remain in the raised position.
[0048] In an embodiment, the pantograph 111 may also include carbon strip 112 configured with the second isolation valve to receive the air stream from the second isolation valve. The current in the locomotive is collected through the carbon strip 112. In case when the carbon strips are broken and the pantograph needs to be raised, the first isolation valve is actuated and then as result of actuation of the first isolation valve, the second isolation valve gets actuated. The activation of the second isolation valve does not allow flow of air stream in the carbon strips as shown in FIG. 3.
[0049] FIG. 4A illustrates an exemplary representation of the pneumatic control unit along with isolation valve 108, in accordance with embodiments of the present disclosure. In an example, the pneumatic control unit may be implemented as part of TCMS unit of the locomotive. As shown in FIG. 4.
[0050] FIG. 4B illustrates an exemplary representation of the pantograph along with the isolation valve 114, in accordance with embodiment of the present disclosure. As shown in FIG. 4B, the isolation valve 114 of the pantograph is connected to pneumatic control unit through a hose connection.
[0051] Thus, the present disclosure provides isolation assembly allowing the pantograph in the raised position of the pantograph even in case of activation of any of ADD and MED valve. Therefore, in cases where the driver needs to raise the pantograph, the driver needs to isolate the ADD & MED. The isolation of ADD and MED valve helps the driver to still raise the pantograph, until the locomotive reaches the nearby station where the pantograph can be inspected for the activation of ADD or MED valve.
[0052] It should be apparent to those skilled in the art that many more modifications besides those already described are possible without departing from the inventive concepts herein. The inventive patient matter, therefore, is not to be restricted except in the spirit of the appended claims. Moreover, in interpreting both the specification and the claims, all terms should be interpreted in the broadest possible manner consistent with the context. In particular, the terms “includes” and “including” should be interpreted as referring to elements, components, or steps in a non-exclusive manner, indicating that the referenced elements, components, or steps may be present, or utilized, or combined with other elements, components, or steps that are not expressly referenced. Where the specification claims refers to at least one of something selected from the group consisting of A, B, C ….and N, the text should be interpreted as requiring only one element from the group, not A plus N, or B plus N, etc. The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the appended claims.
[0053] While the foregoing describes various embodiments of the invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof. The scope of the invention is determined by the claims that follow. The invention is not limited to the described embodiments, versions or examples, which are included to enable a person having ordinary skill in the art to make and use the invention when combined with information and knowledge available to the person having ordinary skill in the art.

ADVANTAGES OF THE INVENTION
[0054] The present disclosure provides an isolation assembly that isolates the ADD and MED to allow continuous movement of the locomotive or to continuously maintain the pantograph in raised position.
[0055] The present disclosure provides an isolation assembly that allows the pantograph to raise even in case of the carbon strips being broken.
[0056] The present disclosure provides an isolation assembly that is provided with isolation valves in the pantograph unit as well as in the pneumatic control unit.
[0057] The present disclosure provides a simple and cost-effective isolation assembly.