DESC:FORM 2

THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENT RULES, 2003

COMPLETE SPECIFICATION
(See Section 10 and Rule 13)

Title of invention:
A FIXTURE FOR A WEB FIT-UP ASSEMBLY

Applicant:
Mazagon Dock Shipbuilders Limited
A company Incorporated in India under the Companies Act, 1956
Under Ministry of Defence,
(A Govt. of India Undertaking)
Having address:
Dockyard Road, Mazagon,
Mumbai - 400010, Maharashtra, India

The following specification particularly describes the invention and the manner in which it is to be performed.

CROSS-REFERENCE TO RELATED APPLICATIONS AND PRIORITY
[001] This patent application claims priority from Indian Provisional Application 201821042832 filed on November 14, 2018.
TECHNICAL FIELD
[002] The present subject matter described herein generally relates to a fixture for a web fit-up assembly.
BACKGROUND
[003] It may be noted that the web fit-up requires ‘C’ type clamps, stoppers and taper wedges made from steel for holding web elements together for fit-up on shop floor and for welding activities. Once the welding of each web element is done, the welded Fasteners and wedges are removed. After removal of the fasteners, the surface needs to be grinded with a grinding machine to achieve clean surface for next joint. After grinding, marking media is applied on the plane surface/working platform.
[004] Further, marking is done on each web element and its segments to place the web element accordingly. With the help of tack-welding, stopper plate is fixed at inner diameter and an outer diameter of the web element. While doing these activities, circularity and alignment of the web element needs to be maintained.
SUMMARY
[005] Before the present apparatus is described, it is to be understood that this application is not limited to the particular machine or apparatus, as there can be multiple possible embodiments that are not expressly illustrated in the present disclosures. It is also to be understood that the terminology used in the description is for the purpose of describing the particular versions or embodiments only and is not intended to limit the scope of the present application. This summary is provided to introduce aspects related to a fixture for a web fit-up assembly, and the aspects are further elaborated below in the detailed description. This summary is not intended to identify essential features of the proposed subject matter nor is it intended for use in determining or limiting the scope of the proposed subject matter.
[006] The present subject matter describes a fixture for a web fit-up assembly. The fixture may comprise a plurality of slots configured in an arc shape. The plurality of slots may be arranged in a circular path and separated by a pre-defined circumferential distance. Further, each of the plurality of slots may be configured for receiving at least one web element. Further, the web element may be configured to be locked in each of the plurality of slots using a set of locking elements. The fixture may further comprise a plurality of connecting element. Each of the plurality of connecting elements may be configured to connect at least two adjacent slots of the plurality of slots. The fixture may further comprise a fitting mechanism. The fitting mechanism may be configured to reduce the pre-defined circumferential distance between each of web elements to zero in order to form the web fit-up assembly.
[007] The fixture disclosed in the present subject matter may be of a metal such as steel and the like extracted from a submarine shell. Further, the set of locking elements of the fixture may be configured with at least one set of hinges, a set of nut-bolts and a set of chains. Furthermore, the fitting mechanism of the fixture may be configured to reduce the pre-defined circumferential distance by moving each of the web elements towards a center of the circular path. The fitting mechanism may be further configured with at least a screw/ bolt and a supporting plate installed at each of the web elements for moving each of the web elements towards the center of the circular path. The fitting mechanism may further comprise at least one heating element to generate heat for moving each of the plurality of web elements towards the center of the circular path. Further, the web element of the fixture may comprise a flange and a web. The web may be welded at an outer surface of the flange.
[008] The present subject matter describes a method of fabricating a web fit-up assembly using a fixture. The method may comprise inserting, a web element in each of a plurality of slots by lifting machines or cranes. Further, the plurality of slots may have a corresponding arc shape and may be arranged in a circular path. The method may further comprise locking the welding element in each of the plurality of slots with a locking element. The method may further comprise reducing the pre-defined circumferential distance between each of the web elements to zero with a fitting mechanism in order to form the web fit-up assembly. The method may further comprise welding each of the web element with each of the adjacent web elements to form a tube or a capsule. The method may further comprise unlocking the set of locking elements to unlock the web element. The method may further comprise removing the fixture from the web fit-up assembly.
[009] Further, the web fit-up assembly is formed for welding preparation by advancing the screw/ bolt provided on the plurality of slots by tightening them using a torque spanner.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] The foregoing summary, as well as the following detailed description of embodiments, is better understood when read in conjunction with the appended drawings. For the purpose of illustrating the disclosure, there is shown in the present document example constructions of the disclosure, however, the disclosure is not limited to the specific methods and apparatus disclosed in the document and the drawing.
[0011] The detailed description is described with reference to the accompanying figures. In the figure, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the drawing to refer like features and components.
[0012] Figure 1 illustrates a fixture for a web fit-up assembly, in accordance with an embodiment of the present subject matter.
[0013] Figure 2 illustrates a method of fabricating a web fit-up assembly using a fixture, in accordance with an embodiment of the present subject matter.
[0014] Figure 3 illustrates a part list of a web fit-up assembly, in accordance with an embodiment of the present subject matter.
[0015] Figure 4 illustrates a web fit-up assembly, in accordance with an embodiment of the present subject matter.
[0016] Figure 5 illustrates a flow chart of a conventional process of fabricating a web fit-up assembly.
[0017] Figure 6 illustrates a flow chart of a process of fabricating a web fit-up assembly, in accordance with an embodiment of the present subject matter.
[0018] The figure depicts various embodiments of the present disclosure for purposes of illustration only. One skilled in the art will readily recognize from the following discussion that alternative embodiments of the fixture for a web fit-up assembly illustrated herein may be employed without departing from the principles of the disclosure described herein.
DETAILED DESCRIPTION
[0019] Some embodiments of this disclosure, illustrating all its features, will now be discussed in detail. The words "comprising", “having”, and "including," and other forms thereof, are intended to be equivalent in meaning and be open ended in that an item or items following any one of these words is not meant to be an exhaustive listing of such item or items, or meant to be limited to only the listed item or items. It must also be noted that as used herein and in the appended claims, the singular forms "a," "an," and "the" include plural references unless the context clearly dictates otherwise. Although any apparatuses and methods similar or equivalent to those described herein can be used in the practice or testing of embodiments of the present disclosure, the exemplary, apparatuses and methods are now described. The disclosed embodiments are merely exemplary of the disclosure, which may be embodied in various forms.
[0020] Various modifications to the embodiment will be readily apparent to those skilled in the art and the generic principles herein may be applied to other embodiments. However, one of ordinary skill in the art will readily recognize that the present disclosure is not intended to be limited to the embodiments illustrated but is to be accorded the widest scope consistent with the principles and features described herein.
[0021] The web fit-up requires ‘C’ type clamps, stoppers and taper wedges made from steel for holding web elements together for fit-up on shop floor and for welding activities. Once the welding of each web element is done, the welded Fasteners and wedges are removed. After removal of the fasteners, the surface needs to be grinded with a grinding machine to achieve clean surface for next joint. After grinding, marking media is applied on the plane surface/working platform.
[0022] Further, marking is done on each web element and its segments to place the web element accordingly. With the help of tack-welding, stopper plate is fixed at inner diameter and an outer diameter of the web element. While doing these activities, circularity and alignment of the web element needs to be maintained.
[0023] All these activities require high amount of human resources, human efforts and time which may sometime leads to fatigue due to activities such as gas cutting, grinding, tack welding, marking, etc., as such activities are repeated after each and every web fit-up assembly. Further, due to the human intervention for the process of making the web fit-up assembly, a lot of errors may occur e.g. the alignment of the web elements may be improper which may further result in misaligned web-fit-up assembly.
[0024] The present subject matter describes a fixture for a web fit-up assembly. The fixture may comprise a plurality of slots. The plurality of slots may have a shape of an arc. Further, the plurality of slots may be arranged in a circular path/circular pattern and may be separated by a pre-defined circumferential distance. Each of the plurality of slots may be capable of receiving at least one web element. Further, after reception of the web element in each of the plurality of slots, the web element may be locked in each of the plurality of slots using a set of locking elements.
[0025] In one embodiment, the fixture may further comprise a plurality of connecting element. Each of the plurality of connecting elements may connect at least two adjacent slots of the plurality of slots. The fixture may further comprise a fitting mechanism. The fitting mechanism may be configured to reduce the pre-defined circumferential distance between each of the plurality of slots to zero in order to form the web fit-up assembly. The fitting mechanism may reduce the pre-defined circumferential distance by moving each of the web elements towards a center of the circular path.
[0026] Furthermore, after the formation of the web fit-up assembly, each of the web element may be welded with each of the adjacent web elements. Further, upon completion of the welding process, the locking element unlocks the web elements. Further, upon unlocking of the web elements, a fixture may be removed from the web fit-up assembly.
[0027] Hence, the fixture for the web fit-up assembly is technically advanced. The fixture may reduce a production time for a fabrication of the web fit-up assembly. Further, use of the fixture may increase an accuracy by enabling the fabrication of perfectly aligned and flawless web fit-up assembly. The use of the fixture may further reduce fatigue of operatives/workers. Further, wastage of non-reusable material and efforts of the workers may be reduced significantly. Further, the fixture is easy to use, does not require regular maintenance and obviates the need of adjustment of diameter for cylindrical frames of a submarine.
[0028] Referring to figure 1, that illustrates a fixture 100 for a web fit-up assembly, in accordance with an embodiment of the present subject matter.
[0029] In one embodiment, the fixture 100 may comprise a plurality of slots 102-a, 102-b….102-n (may also be referred to as a plurality of slots 102, hereinafter), a set of locking elements 104-a, 104-b….104-n (may also be referred to as a set of locking elements 104, hereinafter), a plurality of connecting elements 106-a, 106-b……106-n (may also be referred to as a plurality of connecting elements 106, hereinafter) and a fitting mechanism 108-a, 108-b…..108-n (may also be referred to as a fitting mechanism 108, hereinafter).
[0030] The plurality of slots 102 may have a shape of an arc. The plurality of slots 102 may be arranged in a circular path/circular pattern. Further, the plurality of slots 102 may be separated by a pre-defined circumferential distance. Each of the plurality of slots 102 may be capable of receiving at least one web element (not shown in figure). The web element may comprise a flange and a web which may be collectively referred to as welded frames. Further, the web is welded at an outer surface/curve of the flange. In other words, the outer surface/curve of the flange may match with an inner surface/curve of the webs. Total number of the plurality of slots 102 in the fixture 100 may be equal to the total number of web elements.
[0031] In one embodiment, the web element may be locked in each of the plurality of slots 102 using a set of locking elements 104. The set of locking elements 104 may comprise a set of hinges, a set of nut-bolts, a set of chains, a set of clamps etc.
[0032] In one embodiment, each of the plurality of connecting elements 106 may connect at least two adjacent slots 102 of the plurality of slots 102. The plurality of connecting elements 106 may be fixed at one position.
[0033] In one embodiment, the fitting mechanism 108 may be configured to reduce the pre-defined circumferential distance between each of the web elements to zero in order to form a web fit-up assembly.
[0034] In one embodiment, the fitting mechanism 108 may reduce the pre-defined circumferential distance by moving each of the web elements towards a center of the circular path.
[0035] In one embodiment, the fitting mechanism 108 may comprise at least a screw or a supporting plate installed at each of the plurality of slots 102 for moving each of the web elements towards the center of the circular path.
[0036] In one embodiment, the fitting mechanism 108 may comprise at least a heating element to generate heat for moving each of the web elements towards the center of the circular path.
[0037] In one embodiment, the fixture 100 may be made from scrap or a metal such as a steel structure and the like. The structure may be obtained from a submarine shell for erecting submarines soft patches which may further comprise a shell plate and the welded frames.
[0038] In one embodiment, the fixture 100 may be specially designed according to requirement and structure of the web elements. The fixture 100 may be fixed on a metal platform such as a steel platform with a hanging attachment to remove the web fit-up assembly easily.
[0039] Now, referring to figure 2, that illustrates a method 200 of fabricating a web fit-up assembly using a fixture 100, in accordance with an embodiment of the present subject matter.
[0040] At step 201, the web element may be inserted in each of a plurality of slots 102.
[0041] At step 202, the set of locking element 104 may lock the web element in each of the plurality of slots 102.
[0042] At step 203, the fitting mechanism 108 may reduce the pre-defined circumferential distance between each of the web elements to zero in order to form the web fit-up assembly. Further, tacking may be done to join each of the web elements with each of the adjacent web elements.
[0043] In one embodiment, tacking of stoppers may be done to support the web elements. Further, tacking of claims may be done to arrest/affix the web elements. Furthermore, tacking of pressing lugs may be done. After tacking, inspection may be done in order to examine various parameters of the web fit-up assembly such as alignment of the web elements, circularity of the web fit-up assembly, etc.
[0044] At step 204, once the inspection is done and approved, each of the web elements may be welded with each of the adjacent web elements. Further, after welding, a flush grinding and rectification may be performed on the web fit-up assembly. Further, final inspection may be performed on the web fit-up assembly.
[0045] At step 205, once the final inspection may be performed, the set of locking element 104 may unlock the web elements.
[0046] At step 206, upon unlocking of the web elements, the fixture 100 is removed from the web fit-up assembly.
[0047] In an exemplary embodiment, the fixture 100 may be used for fabrication of the web fit-up assembly of scorpion class submarine having in-side diameter of 5660 mm. The scorpion class submarine has a unique shape and structural design and heavy weight.
[0048] Exemplary embodiments discussed above may provide certain advantages. Though not required to practice aspects of the disclosure, these advantages may include those provided by the following features.
[0049] Some embodiment of the fixture 100 for the web-fit-up assembly may eliminate the need of removing any parts of the fixture 100 or of the web elements by gas cutting or grinding.
[0050] Some embodiment of the fixture 100 for the web-fit-up assembly may enable easy to use mechanism for fabricating the web fit-up assembly.
[0051] Some embodiment of the fixture 100 for the web-fit-up assembly may eliminate the need of special training, frequent maintenance, etc.
[0052] Some embodiment of the fixture 100 for the web-fit-up assembly may eliminate the need of adjustment of diameter for cylindrical frames/web elements of one submarine.
[0053] The foregoing summary of the present subject matter describes a fixture for a web fit-up assembly. The fixture may comprise a plurality of slots configured in an arc shape. The plurality of slots may be arranged in a circular path and separated by a pre-defined circumferential distance. Further, each of the plurality of slots may be configured for receiving at least one web element. Further, the web element may be configured to be locked in each of the plurality of slots using a set of locking elements. The fixture may further comprise a plurality of connecting element. Each of the plurality of connecting elements may be configured to connect at least two adjacent slots of the plurality of slots. The fixture may further comprise a fitting mechanism. The fitting mechanism may be configured to reduce the pre-defined circumferential distance between each of the web elements to zero in order to form the web fit-up assembly.
[0054] The fixture disclosed in the present subject matter may be of a metal such as steel and the like extracted from a submarine shell. Further, the set of locking elements of the fixture may be configured with at least one set of hinges, a set of nut-bolts and a set of chains. Furthermore, the fitting mechanism of the fixture may be configured to reduce the pre-defined circumferential distance by moving each of the web elements towards a center of the circular path. The fitting mechanism may be further configured with at least a screw/ bolt and a supporting plate installed at each of the web elements for moving each of the web elements towards the center of the circular path. The fitting mechanism may further comprise at least one heating element to generate heat for moving each of the web elements towards the center of the circular path. Further, the web element of the fixture may comprise a flange and a web. The web may be welded at an outer surface of the flange.
[0055] Further, the present subject matter describes a method of fabricating the web fit-up assembly using the fixture. The method may comprise inserting, at least one web element in each of a plurality of slots by lifting machines or cranes. Further, the plurality of slots may have a corresponding arc shape and may be arranged in a circular path. The method may further comprise locking, with a locking element, the welding element in each of the plurality of slots. The method may further comprise reducing, with a fitting mechanism, the pre-defined circumferential distance between each of the web elements to zero in order to form the web fit-up assembly. The method may further comprise welding each of the web elements with each of the adjacent web elements to form a tube or a capsule. The method may further comprise unlocking the set of locking elements to unlock the web element. The method may further comprise removing the fixture from the web fit-up assembly.
[0056] Further, the web fit-up assembly is formed for welding preparation by advancing the screw/ bolt provided on the plurality of slots by tightening them using a torque spanner.
[0057] It is to be noted that the fixture for the web fit-up assembly is not limited to submarines and may be implemented on any kind of web elements to form circular/tubular structures.
[0058] Although implementations for the fixture 100 have been described in language specific to structural features and/or methods, it is to be understood that the appended claims are not necessarily limited to the specific features described. Rather, the specific features are disclosed as examples of implementation for the fixture 100.
,CLAIMS:
1. A fixture (100) for a web fit-up assembly, the fixture (100) comprising:
a plurality of slots (102) configured in an arc shape,
wherein the plurality of slots (102) are arranged in a circular path and is separated by a pre-defined circumferential distance,
wherein each of the plurality of slots (102) are configured for receiving at least one web element, and
wherein the web element is configured to be locked in each of the plurality of slots (102) using a set of locking elements (104);
a plurality of connecting elements (106), wherein each of the plurality of connecting elements (106) are configured to connect at least two adjacent slots of the plurality of slots (102); and
a fitting mechanism (108) configured to reduce the pre-defined circumferential distance between each of the web elements to zero in order to form a web fit-up assembly.

2. The fixture (100) of claim 1, wherein the set of locking elements (104) is configured with at least one set of hinges, a set of nut-bolts and a set of chains.

3. The fixture (100) of claim 1, wherein the fixture (100) is of steel extracted from a submarine shell.

4. The fixture (100) of claim 1, wherein the fitting mechanism (108) is configured to reduce the pre-defined circumferential distance by moving each of the web elements towards a center of the circular path.

5. The fixture (100) of claim 4, wherein the fitting mechanism (108) is configured with at least a screw/ bolt and a supporting plate installed at each of the plurality of slots (100) for moving each of the web elements towards the center of the circular path.

6. The fixture (100) of claim 4, wherein the fitting mechanism (108) comprises at least one heating element to generate heat for moving each of the web elements towards the center of the circular path.
7. The fixture (100) of claim 1, wherein the web element comprises a flange and a web, and wherein the web is welded at an outer surface of the flange.

8. A method of fabricating a web fit-up assembly using a fixture (100), the method comprising the steps of:
(i) inserting, a web element in each of a plurality of slots (102) by lifting machines or cranes,
wherein the plurality of slots (102) having a corresponding arc shape and are arranged in a circular path;
(ii) locking the web element in each of the plurality of slots (102) with a set of locking elements (104);
(iii) reducing, the pre-defined circumferential distance between each of the plurality of web elements to zero with a fitting mechanism (108) in order to form a web fit-up assembly;
(iv) welding each of the web element with each of the adjacent web elements to form a tube or a capsule;
(v) unlocking the set of locking elements to unlock the web elements; and
(vi) removing the fixture (100) from the web fit-up assembly.

9.The method of claim 8, wherein the web fit-up assembly is formed for welding preparation by advancing the screw/ bolt provided on the plurality of slots (102) by tightening them using a torque spanner.