Description:DESCRIPTION
“FIXTURE AND METHOD FOR MACHINING TERMINAL BOX OF LARGE SIZE TURBO GENERATORS”

FIELD OF THE INVENTION
[001] The present invention relates to manufacturing of large size turbo generator, such as the ones used in thermal or nuclear power plants. More particularly, the present invention is related to a work holding means i.e. Fixture for machining of terminal Box of a large size turbo generator.
BACKGROUND AND PRIOR ART OF THE INVENTION
[002] 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.
[003] A generator driven by turbine which is used for conversion of mechanical energy to electrical energy, wherein stator frame, rotor, end shield, seal body are the main components of turbo generator. As the turbine rotates, a mechanical rotation is created that drives the generator to produce electrical power. Terminal Box is assembled with the main stator body, through which terminal connection of the stator (same as that of generator) comes out. A terminal box typically accompanies such turbo generator to monitor and control generator operation such that the electrical power is produced in a desired manner to have particular characteristics. Thus, the terminal Box being a very critical component of turbo generator assembly, and should be dimensionally accurate for proper functioning of the machine.
[004] Terminal bushings are assembled to the terminal box and these terminal bushings are connected to the bus bar through flexible connection. Dimensional accuracy of this is very critical for the proper working of the turbo generator. As can be seen in figure-1, this has got a very complex profile and clamping & machining this terminal box is very difficult. Terminal Box of a turbo generator has a complex structure and is prone for distortions during various stages of manufacturing. This gives rise to requirement of machining in different planes which comes with a lot of technical issues pertaining to clamping and machining.
[005] Such issues may range from requirement of too many support blocks, taper shoes and screw jacks needed for clamping of job, continual engagement of overhead crane to support the clamping and associated loss of resource and restriction of operator movement etc. After completing the machining operation in the first setting where marching on the bottom face of the terminal box is done, job is sent to other machine for further machining operation. Same problem related to setting of job is faced there also. In order to eliminate above problems, a need exists for a work holder fixture for machining of terminal box.
[006] Work holders and fixtures have hitherto been employed heretofore to facilitate the proper and rigid clamping and machining of objects at different planes. However, several devices of the prior art have not proven entirely satisfactory in as much as they are complicated in design and construction, expensive to manufacture, and difficult to use.
[007] The manufacture of such heavy and bigger size terminal boxes therefore demand the provisions of correspondingly large manufacturing facilities, with the associated lifting, manipulation, clamping means. This limits the supplier competition which thereby push the cost further up. Also it leads to lower productivity due to profile complexity, which directly impacts the efficiency and cost viability.
OBJECTS OF THE INVENTION
[008] The prime object of the present invention is to obviate one or more of the problems associated with the prior art, whether identified herein or elsewhere. In particular, it is an aim of the present invention to provide an improved method and fixture to accurately manufacture terminal boxes of turbo generators.
[009] Another object of the present invention is to not only save significant manufacturing time involving lesser resources and with accuracy but also with involvement of executing apparatus means that makes this achievable low initial cost and upkeep, great and continuing accuracy inherent in its design and operation, ruggedness and simplicity in its construction and operation, all to the ultimate end of faithfully and consistently reproducing in and through the desired quality of operation.
[0010] Still another object of the present invention is to design and develop an accurate and robust fixture which has to not only hold both the parts at right position, but ensure distortion free stability all throughout the manufacturing process for the terminal box.
[0011] Yet one another object of the invention is to provide machine table mountable work holder for machining of Terminal Box which can be integrated with any machine bed without needing major modifications.
[0012] Yet another object of the invention is to provide machine table mountable work holder for machining of Terminal Box which is affordable so that the device of the invention is easily affordable by small shops and individuals.
[0013] These and other objects and advantages of the present invention will be apparent to those skilled in the art after a consideration of the following detailed description taken in conjunction with the accompanying drawings in which a preferred form of the present invention is illustrated.
SUMMARY OF THE INVENTION
[0014] One or more drawbacks of conventional systems and process are overcome, and additional advantages are provided through the apparatus/composition and a method as claimed in the present disclosure. Additional features and advantages are realized through the technicalities of the present disclosure. Other embodiments and aspects of the disclosure are described in detail herein and are considered to be part of the claimed disclosure.
[0015] According to the invention, there is provided a fixture (F) for machining a terminal box (W, J) of a large size turbo generator comprising of:
- a base plate 1 having a plurality of extruded longitudinal tenons provided thereunder and a plurality of key slots 6 positioned on said base plate to bed to restrict rotary degree of freedom of the fixture F;
- a plurality of angle blocks 2 and support jack 5 securely placed on the base plate 1 to support the load of the job J;
- a plurality of adjustment jacks 4 securely placed on the base plate 1 and multiple taper shoes 3 of each angle block 8 to allow finer adjustments in order to align the job J as per machining requirement for manufacturing;
- multitude of screw clamps 9 to lock in a direction perpendicular to the machine bed and clamps 8 on at least two longitudinal ends of the job J to restrict rotary motion of the job in the plane parallel to the machine bed.
[0016] Further according to the invention, there is provided a method of machining a terminal box (W, J) of a large size turbo generator using the fixture (F) comprising the steps of:
- Securing the base 1 of the fixture F in a machine bed using tenon and threaded means using key slots 6;
- placing and securing angle block 2, taper shoes 3 on the angle block 2, adjustment and support jack 4,5 to support and fine adjust the load of the job J;
- placing the job J on the taper shoes 3 mounted on the angle block 2 and support jack 5, while engaging the overhead crane;
- adjusting the orientation and height of the job J by the rotary to linear movement through the adjustment Jack 4 and in/out wedging movement of the taper shoe 3 to parallel the longitudinal central axis of the job with respect to the machine bed;
- tightening clamps 8 to hold the terminal box (W, J) at this position during the machining, once the finer height adjustments are made.
[0017] The curved part of the terminal box W is towards the adjustment jack 4 side and the joint plane of the terminal box W is towards the angle block 2 side of the fixture F.
[0018] The lifting ribs of the terminal box W are provided to place it securely on the adjustment jacks 4 while the joint plane of the terminal box is placed upon the taper shoe 3 on the angle block 2.
[0019] The jacks 4,5 include screw, pneumatic / hydraulically operated based on the size and weight of the terminal box W.
[0020] The job J is clamped till cools down to ensure that there is no post machining distortion owing the machining heat and stress.
[0021] The adjustment Jack 4 is placed to adjust the orientation and height of the job J, in which the support jack 5 provides the support related requirements of the job J.

[0022] The angle blocks 2 provide the basic clamp height to the clamping arrangement while the taper shoe 3 is incorporated to provide the fine adjustments in the height to adjust and dial the job J face for accurate manufacturing.
[0023] A plurality of threaded holes 7 are provided in the base plate 1 for screwing eye bolts for lifting of the fixture F/ entire fixture with terminal box W by the overhead crane.
[0024] 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.
[0025] It is to be understood that the aspects and embodiments of the disclosure described above may be used in any combination with each other. Several of the aspects and embodiments may be combined to form a further embodiment of the disclosure.
[0026] The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
[0027] The illustrated embodiments of the subject matter will be best understood by reference to the drawings, wherein like parts are designated by like numerals throughout. The following description is intended only by way of example, and simply illustrates certain selected embodiments of devices, systems, and processes that are consistent with the subject matter as claimed herein, wherein:-

[0028] It is to be noted, however, that the appended drawings illustrate only typical embodiments of the present subject matter and are therefore not to be considered for limiting of its scope, for the invention may admit to other equally effective embodiments. The detailed description is described with reference to the accompanying figures. Same numbers are used throughout the figures to reference like features and components. Some embodiments of system or methods in accordance with embodiments of the present subject matter are now described, by way of example, and with reference to the accompanying figures, in which:
[0029] Figure-1: Shows Photographic view of a Turbo generator Terminal Box along with Terminal bushing assembled in accordance to the present invention.
[0030] Figure-2: Shows the work holding fixture F to illustrate the invention in accordance to the present invention.
[0031] Figure-3: Shows the Jacks 4,5 used with work holding fixture F to support and adjustably align the job in accordance to the present invention.
[0032] Figure-4: Shows the Jacks 4,5 used with work holding fixture F to support and adjustably align the job in accordance to the present invention.
[0033] Figure-5: Shows the Clamps 8, angle block 2 and taper shoe 3 used with work holding fixture F to support and adjustably align and clamp the job in accordance to the present invention.
[0034] Figure-6: Shows the clamp screws 9 used with work holding fixture F to rigidly secure the job in accordance to the present invention;
[0035] Figure-7: Shows the isometric view of the work holding fixture F to support and adjustably align the job according to the present invention;

[0036] Figure-8: Shows the work holding fixture F to support and adjustably align the job according to the present invention.
[0037] Figure-9: Shows histogram indicating performance of the Prior art and Present invention.
[0038] The figures depict embodiments of the disclosure for purposes of illustration only. One skilled in the art will readily recognize from the following description that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the disclosure described herein.
DETAILED DESCRIPTION OF THE PRESENT INVENTION WITH REFERENCE TO THE ACCOMPNAYING DRAWINGS
[0039] While the embodiments of the disclosure are subject to various modifications and alternative forms, specific embodiment thereof have been shown by way of example in the figures and will be described below. It should be understood, however, that it is not intended to limit the disclosure to the particular forms disclosed, but on the contrary, the disclosure is to cover all modifications, equivalents, and alternative falling within the scope of the disclosure.
[0040] Before describing in detail, terminal box clamping and machining fixture in accordance with the present invention, it should be observed that the present invention resides primarily in a novel and non-obvious combination of hardware elements and method steps. Accordingly, these elements and steps have been represented by conventional elements and steps in the drawings, showing only those specific details that are pertinent to the present invention so as not to obscure the disclosure with details that will be readily apparent to those skilled in the art having the benefit of the description herein.
[0041] Referring now to figure 2 in detail, the work holding fixture F disclosed therein to illustrate the invention comprising of a machine table mountable base plate 1 serving as the base of the fixture F. Plurality of extruded tenons, like a longitudinal prismatic bar, may also be provided beneath the base plate 1 such that these tenons are received by the T-slot holes of machine bed to restrict the rotary degree of freedom of the fixture F.
[0042] Once the base 1 is secured through the tenon, a plurality of key slots 6 are also provided at the periphery to further secure the base on the machine bed through threaded means. Once the base 1 is secured, jacks 4,5 are secured on the base plate.
[0043] Based on the size and weight of the terminal box W, these jacks 4,5 can be screw, pneumatic or hydraulically operated. As shown in figure 3,4, adjustment Jack 4 is placed to adjust the orientation and height of the job J wherein the support jack 5 caters to the support related requirements of the job J. There is provision of a plurality of angle blocks 2 to provide the basic clamp height to the clamping arrangement while the taper shoe 3 can be incorporated to provide the fine adjustments in the height to adjust and dial the job J face for accurate manufacturing. Once the finer height adjustments are made, the clamps 8 can be utilized to rigidly hold the terminal box at this position during the machining.
[0044] Once the base plate 1 and basic support items as mentioned above are in place, the terminal box W casing can be brought using an overhead EOT crane and placed upon these weight carrying items in a way that the curved part of the terminal box W is towards the adjustment jack 4 side and the joint plane of the terminal box W is toward the angle block 2 side of the fixture F.
[0045] The lifting ribs of the terminal box W are utilized to place it securely on the adjustment jacks 4 while the joint plane of the terminal box is placed upon the taper shoe 3 on the angle block 2. It is to be taken care that till this time the major weight is transferred to the fixture and overhead crane only supports the job for eventuality or mis-happening as the job is still not rigidly clamped.
[0046] Now, the taper shoes 3 and adjustment jacks 4 are threaded adjusted to dial the job as per the job as per the machining required. For example, an in or out wedging movement of the taper shoe 3 to parallel the longitudinal central axis of the job with respect to the machine bed will also tend to rotary swivel the job J around the central axis and therefore adjustment jacks shall be required to compensate this swivel to keep the job J in same plane.
[0047] Once the job J, i.e. the terminal box, is placed and calibrated with respect to the machine bed and the operation to be performed, the job is clamped to be secured at this place while be able to resist the machining forces. For that a plurality of screw clamps 9 are utilized such that when the screw clamp is tightened, it forces the screw 9 head against the job J to lock in a direction perpendicular to the machine bed. Clamps 8 utilize the threaded holes provided in the angle block 2 on at least two longitudinal ends of the job J so as to restrict the rotary motion of the job in the plane parallel to the machine bed.
[0048] Thus during the machining, all rotary and linear motions of the job are restricted to conduct the machining operation for elimination of the issues in the prior art and thus resolve the quality and post machining distortions issues.
[0049] There is a plurality of threaded holes 7 drilled in base plate 1 for screwing eye bolts for lifting of fixture F or entire fixture with terminal box W with the help of overhead EOT crane.
ADVANATAGES OF INVENTION
- Saving of significant manufacturing time involving lesser resources and with accuracy,
- low initial cost and upkeep,
- Accuracy in design and operation,
- Simple in construction and operation,
- Accurate and robust fixture,
- Distortion free stability.
WORKING OF INVENTION

-Fixture F to be fixed on the machine table;
-Terminal Box J to be loaded on the fixture F;
-Tightening clamp 9 and support jacks 5 to be fine adjusted to further fix the terminal box J;
-As the invention F has all its components in place, no separate adjustment is required;
-Terminal Box J is now in position, Machining activity on Terminal Box J is then carried out.

TEST RESULT

Parameter Using Prior Art(s) Using Invention

Reduction in Crane Engagement time

Reduction in the setting time

10 Hrs – Crane Engagement

Crane was held-up for long duration of time to keep the Terminal Box J in position. This hindered the possibility of usage of crane for any other operation/job.
1 Hr – Crane Engagement

Crane is now used only to lift the terminal box J and place on the invention fixture F. The pre-installed components including support blocks, jacks, fixing bolts, tenen, etc. have eliminated the need of crane for continuous holding of the job J.

Reduction in Machining Time 198 Hrs. – using convention tooling

Machining using conventional tooling was done. The prior setup (using crane) in which terminal box J was machined, it was not possible to machine using advanced tool at high RPM speed. 72 Hrs. – using advance tooling

As the terminal box J is now fixed on the invention fixture F, the machining using advanced tool at increased speed (RPM) is now possible. Thus, reducing the machining time.

Reduction in Rework 3-4 %

Rework was present in prior art as the clamping, placing of the job was a make-shift arrangement. Rework due to shifting of components / vibration of components was faced. < 1 %

After the invention fixture F, the terminal box J was fixed firmly on the fixture F and rework was reduced to negligible.

Now, reference may be made to figure 9 reflecting better performance of the present invention over the prior art.

[0050] 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.
[0051] 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.
[0052] It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as “open” terms (e.g., the term “including” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least,” the term “includes” should be interpreted as “includes but is not limited to,” etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases “at least one” and “one or more” to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles “a” or “an” limits any particulars claim containing such introduced claim recitation to inventions containing only one such recitation, even when the same claim includes the introductory phrases “one or more” or “at least one” and indefinite articles such as “a” or “an” (e.g., “a” and/or “an” should typically be interpreted to mean “at least one” or “one or more”); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of “two recitations,” without other modifiers, typically means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogues to “at least one of A, B and C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B and C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). In those instances where a convention analogous to “at least one of A, B, or C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, or C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase “A or B” will be understood to include the possibilities of “A” or “B” or “A and B”.
[0053] The above description does not provide specific details of manufacture or design of the various components. Those of skill in the art are familiar with such details, and unless departures from those techniques are set out, techniques, known, related art or later developed designs and materials should be employed. Those in the art are capable of choosing suitable manufacturing and design details.
[0054] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present disclosure. It will be appreciated that several of the above-disclosed and other features and functions, or alternatives thereof, may be combined into other systems or applications. Various presently unforeseen or unanticipated alternatives, modifications, variations, or improvements therein may subsequently be made by those skilled in the art without departing from the scope of the present disclosure as encompassed by the following claims.
[0055] The claims, as originally presented and as they may be amended, encompass variations, alternatives, modifications, improvements, equivalents, and substantial equivalents of the embodiments and teachings disclosed herein, including those that are presently unforeseen or unappreciated, and that, for example, may arise from applicants/patentees and others.

[0056] While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims.
, Claims:We Claim:
1. A fixture (F) for machining a terminal box (W, J) of a large size turbo generator, the said fixture (F) comprising of:
- a base plate 1 having a plurality of extruded longitudinal tenons provided thereunder and a plurality of key slots 6 positioned on said base plate to bed to restrict rotary degree of freedom of the fixture F;
- a plurality of angle blocks 2 and support jack 5 securely placed on the base plate 1 to support the load of the job J;
- a plurality of adjustment jacks 4 securely placed on the base plate 1 and multiple taper shoes 3 of each angle block 8 to allow finer adjustments in order to align the job J as per machining requirement for manufacturing;
- multitude of screw clamps 9 to lock in a direction perpendicular to the machine bed and clamps 8 on at least two longitudinal ends of the job J to restrict rotary motion of the job in the plane parallel to the machine bed.
2. A method of machining a terminal box (W, J) of a large size turbo generator using the fixture (F) as claimed in Claim 1, wherein said method comprising the steps of:
- Securing the base 1 of the fixture F in a machine bed using tenon and threaded means using key slots 6;
- placing and securing angle block 2, taper shoes 3 on the angle block 2, adjustment and support jack 4,5 to support and fine adjust the load of the job J;
- placing the job J on the taper shoes 3 mounted on the angle block 2 and support jack 5, while engaging the overhead crane;
- adjusting the orientation and height of the job J by the rotary to linear movement through the adjustment Jack 4 and in/out wedging movement of the taper shoe 3 to parallel the longitudinal central axis of the job with respect to the machine bed;
- tightening clamps 8 to hold the terminal box (W, J) at this position during the machining, once the finer height adjustments are made.
3.The fixture and method of machining a terminal box (W, J) of a large size turbo generator as claimed in Claims 1-2, wherein the curved part of the terminal box W is towards the adjustment jack 4 side and the joint plane of the terminal box W is towards the angle block 2 side of the fixture F.
4.The fixture and method of machining a terminal box (W, J) of a large size turbo generator as claimed in Claims 1-3, wherein the lifting ribs of the terminal box W are provided to place it securely on the adjustment jacks 4 while the joint plane of the terminal box is placed upon the taper shoe 3 on the angle block 2.
5.The fixture and method of machining a terminal box (W, J) of a large size turbo generator as claimed in Claims 1-4, wherein the jacks 4,5 include screw, pneumatic / hydraulically operated based on the size and weight of the terminal box W.
6.The fixture and method of machining a terminal box (W, J) of a large size turbo generator as claimed in Claims 1-5, wherein the job J is clamped till cools down to ensure that there is no post machining distortion owing the machining heat and stress.
7.The fixture and method of machining a terminal box (W, J) of a large size turbo generator as claimed in Claims 1-6, wherein adjustment Jack 4 is placed to adjust the orientation and height of the job J, in which the support jack 5 provides the support related requirements of the job J.
8.The fixture and method of machining a terminal box (W, J) of a large size turbo generator as claimed in Claims 1-7, wherein the angle blocks 2 provide the basic clamp height to the clamping arrangement while the taper shoe 3 is incorporated to provide the fine adjustments in the height to adjust and dial the job J face for accurate manufacturing.
9.The fixture and method of machining a terminal box (W, J) of a large size turbo generator as claimed in Claims 1-8, wherein a plurality of threaded holes 7 are provided in the base plate 1 for screwing eye bolts for lifting of the fixture F/ entire fixture with terminal box W by the overhead crane