Claims:1. A detachable plate leveller (alignment tool) for shell and deck plate joining and alignment in hull fabrication shop during critical block fabrication of ship shown comprising of:-

? a 04 mm thick rectangular plate (Item no-1) 150X110 mm size, having rectangular slot at middle 80 mm X 18 mm;

? a rectangular (Item No-2) bar 20 X 16 size and 100 mm length is welded with the slot at the bottom;

? a square bar (Item no-3) kept loose and to be inserted during alignment process along a steel wedge(Item No-4) wherein the said steel wedge is arranged for holding down bend plates with addition of slip ring for thickness adjustment.

2. The detachable plate leveller for shell and deck plate joining as claimed in claim 1, wherein the said rectangular plate (Item no-1) is configured to be inserted between the gap of hull plates in such a manner that the welded square bar is touching the plates from bottom & remaining portion of slot is visible from above the plates.

3. The detachable plate leveller for shell and deck plate joining as claimed in claim 1, wherein the said loose square bar (Item no-3) is inserted in the slot from top the plates.

4. The detachable plate leveller for shell and deck plate joining as claimed in claim 1, wherein the said steel wedge (Item No-4) is inserted into slot on the top of square bar and with controlled hammering wedges the alignment of hull plates is achieved.

5. The detachable plate leveller for shell and deck plate joining as claimed in claim 1, wherein the said alignment tool is configured for addition of angular flexibility of item-2 for holding curvature of bend plate.

6. The detachable plate leveller for shell and deck plate joining as claimed in claim 1, wherein the said alignment tool is configured to simplify the aligning work and many redundant activities like fitment of L-clamp, strong-backs, burr grinding, pit-hole welding and regrinding are eliminated.
, Description:DEVELOPMENT OF DETACHABLE PLATE LEVELERS FOR SHELL
AND DECK PLATE JOINING AND ALIGNMENT

FIELD OF INVENTION
The present invention relates to development of detachable plate leveller for shell and deck plate joining and alignment. More particularly, the present invention is associated with hull fabrication shop and is responsible for alignments and plate joining in critical block fabrication of ships.

BACKGROUND ART
Plate joining is one of the vital activities of any hull fabrication work and as such any delay in this activity will ultimately result in delay in the block completion. The traditional method of plate joining involves many non-productive activities like fitment of strong backs, fitment of L-Clamp, grinding of Burr, Build-up of pit-holes etc. which not only consuming productive man-hour but also causing deterioration of the quality of plates due to pit-hole left out after grinding and excessive heating of area near plate joint.

Shipbuilding shop (GRSE, Main) undertake fabrication of Hull Block of ship. Plate joining is one of the vital operation of any hull fabrication work as such any delay in this activity ultimately cause delay in the Block completion. In the traditional method of plate joining, the plates to be joined are at first firmly secured on skid then L-Clamp is suitably tack welded on one of the plate surface (i.e. surface which is higher) followed by insertion of steel wedge below L-clamp and thereafter controlled hammering of wedges to achieve levelling of edges of plates. Once a particular area is completely levelled by this way, the strong backs are tack welded on the plate surface to retain level (As shown in Figure-1). The L-clamp is then removed and again tack welded in the new location. The preceding process is repeated throughout the length of joint. Lastly the Ceramic holding clamp (C-Clamps) is tack welded in the opposite side of plate joint (As shown in Figure-2) and strong backs removed which leave behind huge numbers of burrs (As shown in Figure-3) that need to be grounded smooth before start of welding. After grinding of burr, it is evident that some pit-holes arises which need to be build-up by weld drops and then regrind to achieve smooth surface. As obvious, there are many redundant activities like L-clamp fitment, strong-back fitment, grinding, build-up etc. which are not only time consuming but also affecting production schedules and also causing deteriorating of the quality of plates due to pit-hole left out after grinding and excessive heating of area near joint.

OBJECT OF INVENTION
In is a prime object of the present invention is to provide ‘detachable plate leveller’ configured to do away with all the non-productive steps associated with existing plate joining activities. The design of the leveller is simpler to apply and sped up the work with less man-hour requirement and improvement in quality of work.

SUMMARY OF INVENTION
The present innovation relates to the innovative process adopted for shell and deck plate joining activities during hull block fabrication inside shop floor.
The “detachable plate levellers” shown in Fig 5 is a simple tool consists of:
1) 04 mm thick rectangular plate 150X110 mm size, having rectangular slot at middle 80 mm X 18 mm
2) 01 nos. rectangular bar 20 X 16 size and 100mm length is welded with the slot at the bottom
3) 01 no. square bar kept loose and to be inserted during alignment process along with steel wedge
4) 01 nos. Steel wedges
The rectangular plate (Item no-1) to be inserted between the gap of hull plates in such a manner that the welded square bar is touching the plates from bottom & remaining portion of slot is visible from above the plates. Then the loose square bar (Item no-3) is inserted in the slot from top the plates, after that steel wedge (Item No-4) is inserted into slot on the top of square bar and with controlled hammering wedges the alignment of hull plates is achieved. With this alignment tool, it is found that alignment work is simplified and many redundant activities involved with the previous methods like fitment of L-clamp, strong-backs, burr grinding, pit-hole welding and regrinding etc. has been eliminated successfully.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Fig. 1 illustrates non-productive activity of existing method “Strong back fitment on plate surface” as prior art;
Fig. 2 illustrates fitment of C-Clamp in the back side of plate (Existing method) as prior art;
Fig. 3 illustrates Burr left over after removal of Strong back (Existing method) as prior art;
Fig. 4 illustrates drawing of ‘detachable plate leveller’ complete arrangement in accordance with the present invention;
Fig. 5 illustrates photograph of ‘detachable plate leveller’ in accordance with the present invention;
Figure-6 & 7 illustrates the arrangement of “Detachable plate levellers” for fit-up and levelling of Deck plates in accordance with the present invention;
Figure-8 illustrates close view of leveller in fit-up condition in accordance with the present invention.

DETAILED DESCRIPTION
Shipbuilding shop (GRSE, Main) undertake fabrication of Hull Block of ship. Plate joining is one of the vital operation of any hull fabrication work as such any delay in this activity ultimately cause delay in the Block completion. In the traditional method of plate joining, the plates to be joined are at first firmly secured on skid then L-Clamp is suitably tack welded on one of the plate surface (i.e. surface which is higher) followed by insertion of steel wedge below L-clamp and thereafter controlled hammering of wedges to achieve levelling of edges of plates. Once a particular area is completely levelled by this way, the strong backs are tack welded on the plate surface to retain level (As shown in Figure-3). The L-clamp is then removed and again tack welded in the new location. The preceding process is repeated throughout the length of joint. Lastly the Ceramic holding clamp (C-Clamps) is tack welded in the opposite side of plate joint and strong backs removed which leave behind huge numbers of burrs (As shown in Figure-4) which need to be grounded smooth before start of welding. After grinding of burr, it is evident that some pit-holes arises which need to be build-up by weld drops and then regrind to achieve smooth surface. As obvious, there are many redundant activities like L-clamp fitment, strong-back fitment, grinding, build-up etc. which are not only time consuming but also affecting production schedules and also causing deteriorating of the quality of plates due to pit-hole left out after grinding and excessive heating of area near joint.
The present innovation relates to the innovative process adopted for shell and deck plate joining activities using specially designed ‘detachable plate levellers’.
The “detachable plate levellers” shown in Fig 8 is a simple tool consists of
1) 04 mm thick rectangular plate 150X110 mm size, having rectangular slot at middle 80 mm X 18 mm
2) 01 nos. rectangular bar 20 X 16 size and 100mm length is welded with the slot at the bottom
3) 01 no. square bar kept loose and to be inserted during alignment process along with steel wedge
4) 01 nos. Steel wedges
The rectangular plate (Item no-1) to be inserted between the gap of hull plates in such a manner that the welded square bar is touching the plates from bottom & remaining portion of slot is visible from above the plates. Then the loose square bar (Item no-3) is inserted in the slot from top the plates, after that steel wedge (Item No-4) is inserted into slot on the top of square bar and with controlled hammering wedges the alignment of hull plates is achieved. With this alignment tool, it is found that alignment work is simplified and many redundant activities involved with the previous methods like fitment of L-clamp, strong-backs, burr grinding, pit-hole welding and regrinding etc. has been eliminated successfully.

INVENTIVE STEPS
1. Design for plate levelling & fit-up work using “Detachable plate leveller”
2. Design of “Detachable plate leveller” for holding down bend plates as shown in Fig 6 and 7.
3. Design for holding down bend plates with addition of slip ring for thickness adjustment.
4. Design for plate levelling & fit-up work with addition of angular flexibility of item-2 for holding curvature of bend plate.

ADVANTAGES AND INDUSTRIAL APPLICATION OF INVENTION
The concept, design and method of shell and deck plate butt joint levelling & fit-up using present invention (i.e. using detachable plate levellers) is a quantum leap in the said work resulting work simplification, huge saving in Man-hours and materials. This job simplification is mainly due to elimination of all the non-productive activities like fitment of strong backs, fitment of L-Clamp, grinding of Burr, Build-up of pit-holes etc. Due to above there is a reduction in Man-hour consumption by 60 % and material usage as fabrication aid by 80 %.

Apart from above tangible gain there is great improvement in quality of work and morale of workman which can’t be quantified.

Although the foregoing description of the present invention has been shown and described with reference to particular embodiments and applications thereof, it has been presented for purposes of illustration by way of examples and description and is not intended to be exhaustive or to limit the invention to the particular embodiments and applications disclosed. The particular embodiments and applications were chosen and described to provide the best illustration of the principles of the invention and its practical application to thereby enable one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. All such changes, modifications, variations, and alterations should therefore be seen as being within the scope of the present invention as determined by the appended claims when interpreted in accordance with the breadth to which they are fairly, legally, and equitably entitled.