DESC:TECHNICAL FIELD
[0001] The present disclosures relates to the field of protection devices. More particularly, the present disclosure relates to circuit breakers having means that provide rolling arrangement for rail system of circuit breakers cradle.

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] Circuit breakers are incorporated in a power supply circuit for protection against potential damage that may be caused to electrical circuit and connected load by potentially damaging occurrences such as but not limited to overvoltage, short-circuit etc. Circuit breakers are designed to detect such potentially dangerous conditions and operate to disconnect the load automatically. After a fault has been diagnosed and rectified, circuit breaker can be either manually or remotely reset and power supply circuit can resume its normal operations/ functioning. They can also be used to isolate the connected load from power supply that may become necessary for various reasons such as maintenance.
[0004] Circuit breakers are designed according to their operating environment and intended purpose. They come in many different sizes and shapes. Circuit breakers are also of many different types such as fixed type and extractable or withdrawal or draw out type. Fixed types of Circuit Breakers are standalone and need no external enclosure for their operations. Medium-voltage circuit breakers in switchgear line-ups are often built with draw-out construction, allowing breaker removal without disturbing power circuit connections. In draw out type of Circuit Breakers, the circuit breaker is on a cradle housed inside an external frame or enclosure that encases the circuit breaker within in such a way that the circuit breaker can be switched off and extracted from within the enclosure for maintenance using a motor-operated or hand-cranked mechanism to separate the breaker from its enclosure.
[0005] To facilitate extraction/withdrawal of the circuit breaker from its enclosure, a raking system is typically provided wherein the circuit breaker cradle incorporates a rail and movedinward/outward. In existing raking systems rail is provided a continuous supportthroughout its length by a guide arrangement. Railsare supported on the guide arrangement in one direction only and are restricted from lateral movement by means of rail flanges.
[0006] Continuous supported guide arrangement for rails that is provided by most of the switchgear manufacturers, results in surface contact between two sliding parts i.e. rail and guide arrangement and results in high friction and hence more effort is needed for inward/outward movement of circuit breaker. Also as the rails are configured to slide over a fixed support, they both are prone to extensive wear reducing their life.
[0007] There is therefore a need in the art for an improved arrangement for drawing out of circuit breaker that provides smooth movement, needs less effort, keeps the rail vertically and laterally stable and has better service life.
[0008] All publications herein are incorporated by reference to the same extent as if each individual publication or patent application were specifically and individually indicated to be incorporated by reference. Where a definition or use of a term in an incorporated reference is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply.
[0009] In some embodiments, the numbers expressing quantities of ingredients, properties such as concentration, reaction conditions, and so forth, used to describe and claim certain embodiments of the invention are to be understood as being modified in some instances by the term “about.” Accordingly, in some embodiments, the numerical parameters set forth in the written description and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by a particular embodiment. In some embodiments, the numerical parameters should be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of some embodiments of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as practicable. The numerical values presented in some embodiments of the invention may contain certain errors necessarily resulting from the standard deviation found in their respective testing measurements.
[0010] 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.
[0011] The recitation of ranges of values herein is merely intended to serve as a shorthand method of referring individually to each separate value falling within the range. Unless otherwise indicated herein, each individual value is incorporated into the specification as if it were individually recited herein. 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.
[0012] 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 Markush groups used in the appended claims.

OBJECTS OF THE INVENTION
[0013] An object of the present disclosure is to overcome problems associated with existing raking system of draw out type circuit breakers.
[0014] Another object of the present disclosure is to provide a raking system for draw out type circuit breakers that requires lower effort to move circuit breaker inward/outward and removes sluggishness in its movement.
[0015] Another object of the present disclosure is to provide a raking system for draw out type circuit breakers that has lower wear and extended life.
[0016] Another object of the present disclosure is to provide a raking system for draw out type circuit breakers that incorporates roller support for the rails resulting in lower friction and wear.
[0017] Another object of the present disclosure is to provide a raking system for draw out type circuit breakers that is easy to assemble and rigid in construction.
[0018] Another object of the present disclosure is to provide a raking system for draw out type circuit breakers that does not allow slipping and tilting of rail from the cradle body ensuring proper breaker movement in cradle.
[0019] Another object of the present disclosure is to provide a raking system for draw out type circuit breakers that provides only one direction of freedom to rail and keeps the circuit breaker vertically and laterally stable.

SUMMARY
[0020] Aspects of the present disclosure relate to railing system of draw out type circuit breakers. In an aspect, the disclosure provides a rail that is supported on rollers instead of sliding on contact surface prevalent in conventional system thus removes sluggishness in movement, reduces effort required to move circuit breaker inward/outward and enhances service life due to reduced wear.
[0021] In an embodiment, the present disclosure provides for a rail guided by a top rail guide and a bottom rail guide. The two rail guides are configured with rollers to support the rail in mutually perpendicular directions. In an aspect, the bottom rail guide is configured with rollers that are placed horizontally i.e. their axis of rotation is horizontal and these rollers support the rail in vertical direction. On the other hand, the top rail guide is configured with rollers that are placed vertically i.e. their axis of rotation is vertical and these rollers support the rail in lateral/horizontal direction.
[0022] In an embodiment, combination of horizontally placed rollers in the bottom rail guide and vertically placed rollers in the top rail guide restrict the rail to only one degree of freedom in a direction that is perpendicular to the plane of axis of rotation of vertically placed rollers and axis of rotation of horizontally placed rollers and eliminate any possibility of vertical and lateral/horizontal movement. Thus, the disclosed configuration does not allow slipping and tilting of rail from the cradle body ensuring proper breaker movement in cradle. It is also is easy to assemble and rigid in construction.
[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 THE 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] FIG. 1 illustrates an exemplary schematic arrangement of the proposed railing arrangement in accordance with an embodiment of the present disclosure.
[0026] FIG. 2 illustrates an exemplary end view of the proposed railing arrangement in accordance with an embodiment of the present disclosure.
[0027] FIG. 3 illustrates an exemplary isometric view of bottom rail guide assembly in accordance with an embodiment of the present disclosure.
[0028] FIG. 4 illustrates an exemplary isometric view of top rail guide assembly in accordance with an embodiment of the present disclosure.

DETAILED DESCRIPTION
[0029] 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.
[0030] Each of the appended claims defines a separate invention, which for infringement purposes is recognized as including equivalents to the various elements or limitations specified in the claims. Depending on the context, all references below to the "invention" may in some cases refer to certain specific embodiments only. In other cases it will be recognized that references to the "invention" will refer to subject matter recited in one or more, but not necessarily all, of the claims.
[0031] 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.
[0032] 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.
[0033] Various terms as used herein are shown below. To the extent a term used in a claim is not defined below, it should be given the broadest definition persons in the pertinent art have given that term as reflected in printed publications and issued patents at the time of filing.
[0034] Embodiments of the present disclosures relates to protection devices used in low or medium voltage electric supply systems. More particularly, the present disclosures relates to railing arrangement in draw out type circuit breakers. The disclosure provides a rail that is supported on rollers instead of sliding on contact surface as prevalent in conventional system thus overcomes problem of sluggishness movement, reduces effort required to move circuit breaker inward/outward and enhances service life due to markedly reduced wear.
[0035] In an embodiment, two sets of rollers are provided wherein the first set of rollers supports the rail in vertical direction and the second set supports it in lateral direction. The first set of rollers is configured on a bottom railguide and the second set of the rollers is configured on a top railguide. The bottom railguide and the top railguide are configured on side wall of the cradle. Thus the disclosed configuration does not allow slipping and tilting of rail from the cradle body as the rail carrying the circuit breaker moves to and fro in the cradle thus ensuring proper breaker movement in cradle. It is also is easy to assemble and rigid in construction. In an aspect there could be more than one set of rail and corresponding bottom rail guide and top rail guide in a cradle assembly wherein the sets of rail and corresponding bottom rail guide and top rail guide are positioned on one or more walls of the cradle of the circuit breaker.
[0036] Referring now to FIG. 1 which illustrates an exemplary schematic diagram of the disclosed railing arrangement wherein a rail 100, which is supported by a bottom rail guide assembly 200 and a top rail guide assembly 300 is free to slide to and fro, wherein the bottom rail guide assembly 200 and the top rail guide assembly 300 are mounted on a cradle side plate 400.
[0037] FIG. 2 illustrates an exemplary end view of the proposed railing arrangement in accordance with an embodiment of the present disclosure. Shown therein is the rail 100 supported by the bottom rail guide assembly 200 in vertical direction and the top rail guide assembly 300 in lateral direction. Further the bottom rail guide assembly 200 and the top rail guide assembly 300 are mounted on a cradle side plate 400.
[0038] In an aspect there could be more than one set of the rail 100 and the corresponding bottom rail guide assembly 200 and the top rail guide assembly 300 in a cradle assembly wherein the sets of the rail 100 and the corresponding bottom rail guide assembly 200 and the top rail guide assembly 300 are positioned on one or more walls of the cradle of the circuit breaker to provide proper support to the circuit breaker.
[0039] FIG. 3 illustrates an exemplary isometric view of the bottom rail guide assembly 200 in accordance with an embodiment of the present disclosure. As shown the bottom rail guide assembly 200 can incorporate plurality of bottom rollers 202 with a horizontal axis of rotation. The bottom rollers 202 can be mounted on plurality of corresponding bottom roller locking pins 204 that are placed horizontally to provide a horizontal axis of rotation to the bottom rollers 202.
[0040] In an embodiment, the bottom rail guide assembly 200 can be made of two plates, one being bottom roller holder plate206 and other being a bottom roller support plate 208 as shown in FIG.3.The bottom roller support plate 208 can hold bottom roller locking pins 204 that hold the bottom rollers 202. Bottom end/edge of the rail 100 can rest on bottom rollers 202 to provide vertical support as the rail makes to and fro movement while the bottom roller support plate 208 can provide lateral support to the bottom end/edge of the rail 100. In an aspect, the movement of the rail 100 on bottom rollers 202 eliminates sliding motion replacing it with rolling movement (having lower coefficient of friction) and ensures effortless smooth movement free from sluggishness.
[0041] FIG. 4 illustrates an exemplary isometric view of top rail guide assembly 300 in accordance with an embodiment of the present disclosure. As shown, the top rail guide assembly 300 can incorporate plurality of top rollers 302 with a vertical axis of rotation. the top rail guide assembly 300 can comprise a generally ‘C’ shaped top rail guide 304 and the top rollers 302 can be placed within the ‘C’ shape by means of plurality of corresponding top roller locking pins 306 that can be vertical to provide a vertical axis of rotation to the top rollers 302. Upper end/edge of the rail 100 can be supported by top rollers 302 to provide lateral support to the rail 100 as it makes to and fro movement. In an aspect, the lateral support to the rail 100 by the top rollers 302 does not allow slipping and tilting of rail from the cradle body as the rail carrying the circuit breaker moves to and fro in the cradle thus ensuring proper breaker movement in cradle.
[0042] In an aspect, combination of horizontally placed bottom rollers 202 in the bottom rail guide assembly 200 and vertically placed top rollers 302 in the top rail guide assembly 300restrict the rail 100 to only one degree of freedom in a direction that is perpendicular to the plane of axis of rotation of bottom rollers 202 and axis of rotation of top rollers 302 and eliminate any possibility of vertical and lateral/horizontal movement. Thus the disclosed configuration does not allow slipping and tilting of rail 100 from the cradle body ensuring proper breaker movement in cradle. It is also is easy to assemble and rigid in construction.
[0043] As can be appreciated, the present disclosure solves the issue regarding rail sluggishness, enhances racking operation of the breaker and improves service life of the system. The proposed disclosure further solves the problem of slipping and tilting of rail 100 from the cradle body ensuring proper breaker movement in cradle. The proposed disclosure further provides a new method of mounting of rail and an improvement to an existing constructions.
[0044] In another aspect, top rollers302 can act as side thrust absorbing members and maintain stability of the breaker. Furthermore, the roller guide system can be configured to require less force to operate and ensure smooth and reliable operation. Due to the proposed arrangement, static friction of the system due to inertial load of the breaker is reduced. Roller arrangement provides line/rolling contact with the rail to minimize friction force and give smooth movement of rail 100 in the rail guides. The effort required to move the rail gets significantly reduced due to this anti-friction arrangement.
[0045] In an aspect, the proposed disclosure enabled provision of smooth rail movement because of line/roller contact of rail and guide. In another aspect, side thrust load that is experienced by rails when the circuit breaker is loaded is countered by the rollers for greater stability and hence, reliability in operation. The proposed system is also easy to assemble, rigid in construction, and ensures motion with single degree of freedom.
[0046] 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
[0047] The present disclosure overcomes problems associated with existing raking system of draw out type circuit breakers.
[0048] The present disclosure provides a raking system for draw out type circuit breakers that requires lower effort to move circuit breaker inward/outward and removes sluggishness in its movement.
[0049] The present disclosure provides a raking system for draw out type circuit breakers that has lower wear and extended life.
[0050] The present disclosure provides a raking system for draw out type circuit breakers that incorporates roller support for the rails resulting in lower friction and wear.
[0051] The present disclosure provides a raking system for draw out type circuit breakers that is easy to assemble and rigid in construction.
[0052] The present disclosure provides a raking system for draw out type circuit breakers that does not allow slipping and tilting of rail from the cradle body ensuring proper breaker movement in cradle.
[0053] The present disclosure provides a raking system for draw out type circuit breakers that provides only one direction of freedom to rail and keeps the circuit breaker vertically and laterally stable.
,CLAIMS:1. A railing system for draw out type circuit breakers, the railing system comprising:
at least one bottom rail guide assembly configured with plurality of horizontally placed bottom rollers;
at least one top rail guide assembly configured with plurality of vertically placed top rollers; and
at least one rail configured between the at least one bottom rail guide assembly and the at least one top rail guide assembly such that bottom edge of the rail is vertically supported by the plurality of horizontally placed bottom rollers and upper edge is laterally supported by the plurality of vertically placed top rollers.
2. The railing system of claim 1, wherein the at least one bottom rail guide assembly and the at least one top rail guide assembly are configured on a side wall of a cradle assembly.
3. The railing system of claim 1, wherein the at least one bottom rail guide assembly further comprises a bottom roller holder plate and a bottom roller support plate.
4. The railing system of claim 3, wherein the bottom roller supports plate provides lateral support to the bottom edge of the rail.
5. The railing system of claim 3, wherein the plurality of bottom rollers are mounted on corresponding bottom roller locking pins.
6. The railing system of claim 5, wherein the bottom roller locking pins are held on the bottom roller support plate.
7. The railing system of claim 1, wherein the at least one top rail guide assembly further comprises a top rail guide.
8. The railing system of claim 7, wherein the top rail guide is ‘C’ shaped.
9. The railing system of claim 9, wherein the plurality of vertically placed top rollers are configured within the ‘C’ shape of the top rail guide by means of plurality of top roller locking pins.
10. A draw out type circuit breaker comprising:
a cradle having at least one side wall;
at least one bottom rail guide assembly configured on the at least one side wall; and the at least one bottom rail guide assembly comprising plurality of horizontally placed bottom rollers;
at least one top rail guide assembly configured on the at least one side wall; and the at least one top rail guide assembly comprising plurality of vertically placed top rollers; and
at least one rail configured between the at least one bottom rail guide assembly and the at least one top rail guide assembly such that bottom edge of the rail is vertically supported by the plurality of horizontally placed bottom rollers and upper edge of the rail is laterally supported by the plurality of vertically placed top rollers.