DESC:WELDING EQUIPMENT WITH MOVING FIXTURE/S AND WELDING METHOD THEREOF
FIELD OF INVENTON
[0001] This invention relates to a welding technology and more particularly relates to a welding equipment for welding critical components and to a method thereof.

BACKGROUND OF THE INVENTION
[0002] Conventional technique to weld critical assemblies (for example, vehicle chassis, swing arm, engine hanger etc.) consists of welding the assembly in 2 stages. Welding of first half portion is completed in stage 1 on one fixture. The welded job is removed from the first fixture and then loaded on another fixture. Welding of remaining second half portion is completed in stage 2 on another fixture. This method creates weld overlap on outer side of frame which is aesthetic area. Also, the output of 1st stage may have deviations due to welding distortion. This leads to stressed fitment of sub assembly in the fixture during second stage. Due to this, a weld run of second stage may shift or overlap on weld run of first stage. This result in hampering of aesthetic look of open area or aesthetic area of the vehicle, also may lead to poor quality of weld.
[0003] Another disadvantages are dents due to manual handling of frame, requires more floor space and more time for two stages of welding.

OBJECT OF THE INVENTION
[0004] An object of present invention is to provide a welding equipment & method, which delivers high quality in all round welding done in a single setup.
[0005] An another object of the present invention is to combine two welding stages into single stage eliminating welding issue (for example distortion, weld overlap etc.).
[0006] Yet another object of the present invention is to reduce manual handling of frame, thereby eliminating damages due to dents.
[0007] Still another object of the invention to provide a welding equipment, which requires less floor space than comparable equipment operating at the same production rate.
[0008] Yet another object of the invention to provide a welding equipment & method, which delivers high quality in all round welding done in single setup.

SUMMARY OF PRESENT INVENTION
[0009] According to one of the preferred embodiment of the present invention, a welding equipment comprising plurality of fixtures characterized in that; at least one fixture is an indexing fixture and at least one fixture is a moving fixture and wherein one fixture moves away from other fixture during at least one of the predefined welding stage/s.
[0010] Preferably in the said welding equipment; the moving fixture moves away from the indexing fixture during at least one of the predefined welding stage/s of welding method.
[0011] Preferably in the said welding equipment, the moving fixture is moved by a moving arrangement.
[0012] Preferably in the said welding equipment, the moving arrangement compromises a telescopic lifers for supporting the moving fixture and a pneumatic lifter cylinder for moving the moving fixture.
[0013] Preferably in the said welding equipment, the indexing fixture is indexed by a servo driven rotating unit.
[0014] Preferably in the said welding equipment, the moving fixture and the indexing fixture comprises;
locating means for locating one fixture with other fixture; and
clamping means for clamping both fixtures and;
provision for clamping child parts on fixtures.
[0015] Preferably in the said welding equipment, the locating means is a locating pin and clamping means is a wedge clamp.
[0016] Preferably in the said welding equipment, the actions of indexing, moving and clamping are controlled by a programmable logic controller PLC.
[0017] Preferably in the said welding equipment, the welding equipment comprises a spatter guard, which is brought forward between the moving fixture and the indexing fixture to safeguard the moving fixture from splashed of welding done on the indexing fixture especially when the moving fixture moves away from the indexing fixture.
[0018] Preferably in the said welding equipment, the welding equipment comprises an automatic/robotic welding gun used for welding and is controlled by a programmable logic controller PLC.
[0019] Preferably in the said welding equipment, the moving fixture is operated by a pneumatic or hydraulic or mechanical or electrical or similar arrangements and the moving action is in the form of sliding or lifting.
[0020] Preferably in the said welding equipment, the indexing fixture is rotated by mechanical arrangements actuated by Pneumatic or Hydraulic or electrical means.
[0021] Preferably a welding method with the use of the said welding equipment comprises steps of;
a) loading of the child part (17) on the indexing fixture (5);
b) automatic clamping of the child part (17) on the indexing fixture (5);
c) indexing of the indexing fixture (5) to a desired position;
d) triggering of a pneumatic cylinder (7) by a signal from a programmable logic controller (PLC) (14) to move the moving fixture (8) towards the indexing fixture (5);
e) positioning of the moving fixture (8) with the indexing fixture (5) by locating the fixture (5) by locating means (9) and locking in place by clamping means;
f) loading of the child part/s (17) on the moving fixture (8);
g) automatic clamping of t child part/s (17) on the moving fixture (8);
h) receiving welding start command from the operator;
i) performing inside welding of the child parts (17) clamped on the indexing fixture (5) and the moving fixture (8) using an automatic/ robotic welding gun (13);
j) unclamping of the moving fixture (8) from the indexing fixture (5) and from the welded child part/s (17);
k) triggering of the pneumatic cylinder (7) by a signal from the PLC (14) to move the moving fixture (8) away from the indexing fixture (5);
l) bringing a spatter guard (15) between the moving fixture (8) and the indexing fixture (5),
m) performing indexing of the indexing fixture (5) to desired position;
n) performing remaining welding of said child part/s (17) on the indexing fixture (5) using the automatic/ robotic welding gun (13);
o) indexing of the indexing fixture (5) to convenient position for operator; and
p) unclamping and unloading of the welded child part/s (17) from the indexing fixture (5).
BRIED DESCRIPTION OF DRAWINGS:
The invention will now be described in more detail by way of example with reference to the embodiments shown in the figures mentioned below:
FIG. 1 is a pictorial front view of a welding equipment having two fixtures according to prior art of the present invention.
FIG. 2 is a pictorial view of a welding equipment according to one embodiment of the present invention where both fixtures are away from each other.
FIG. 3 is a pictorial view of a welding equipment according to one embodiment of the present invention where both fixtures are close to each other.
FIG. 4 is a pictorial front view of overall layout of a welding equipment according to one embodiment of the present invention.
FIG. 5 is a side view of the welding equipment shown in FIG. 1.
FIG. 6 is a top view of the welding equipment shown in FIG. 1.
FIG. 7 is a front view of overall layout of a welding equipment when moving fixture is moved away from indexing fixture.
FIG. 8 is a child part locating and resting arrangement according to one embodiment of the present invention.

DESCRIPTION OF PREFERRED EMBODIMENT
[0022] Embodiments of present invention will now be explained with the help of figures herein below. All the aspects described herein will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following descriptions, while indicating preferred embodiments and numerous specific details thereof, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope herein without departing from the spirit and scope thereof, and the present invention herein includes all such modifications.
[0023] FIG. 1 shows a welding equipment (200) according to prior art where two separate fixtures (A) & (B) are provided. In this set up, some child parts are welded on fixture (A) to make a sub-assembly (C). Then a welded sub-assembly (C) is removed from fixture (A) and mounted on fixture B). Additional child parts are welded on this fixture to form a complete assembly D). This system suffers from various disadvantages, as explained in previous sections herein above.
[0024] To overcome the various lacunas of the prior art system, the present invention provides a welding equipment and method of welding critical assemblies for example, vehicle chassis or frame, swing arm, engine hanger etc.) in a single setup is explained in details in following paras as per one of the embodiment of the present invention with the help of FIG. 2 to 8.
[0025] A welding equipment (100) comprises a base (1), an indexing fixture (5), a moving fixture (8) also called as disappearing fixture. The base (1) supports all units of the equipment. The indexing fixture (5) is supported by L.H. support (3) & R.H. support (4) and indexed by a servo driven rotating unit (2). The moving fixture (8) is moved by a moving arrangement, which comprises four telescopic lifters (6) and a pneumatic lifter cylinder (7). At start of an operation, the indexing fixture (5) is positioned in 1st position. Then operator loads some child parts (17) on indexing fixture (5) and the child parts (17) are clamped on the indexing fixture (5). Refer FIG. 2. After this, operator gives authorization through P.L.C. programmable logic controller (14). Following which the indexing fixture (5) attains 2nd desired position. Once indexing fixture (5) is positioned, P.L.C. (14) triggers valve of pneumatically operated pneumatic cylinder 6) to move the moving fixture (8) towards the indexing fixture (5). Refer FIG. 3. The moving fixture (8) is supported by telescopic lifters (7) while moving. Once the moving fixture (8) butts with the indexing fixture (5), it is located by fixture locating means for example location pins (9). Once confirmation signal for fixture butting is provided by position sensor (25) for example reed switch), which is mounted on pneumatic lifter cylinder (7), wedge clamps are pushed forward against taper. It clamps the moving fixture (8) against the indexing fixture (5) and thus ensures perfect butting. Wedge clamps remains in this position until retracted by pneumatic cylinder (7). Both fixtures are positioned with high accuracy by locating them with fixture location pins (9). FIG. 7 shows enlarged view of fixture location pins (9). Once moving fixture (8) attains its desired position, P.L.C. (14) signals for further operation. If desired by method as mentioned in another embodiment above) operator loads remaining child parts (17) in respective positions on the indexing fixture (5). Child parts (17) are located by part location pins (11) provided on fixture (5) and are rested on rest pads (11a). Refer FIG. 8. After child parts loading activity is completed, operator authorizes to start the cycle. Parts are sensed for their presence and correct position by position sensors (25) For example seat check sensor. Inside welding of child parts (17) is completed by automatic/ robotic welding gun (13) for example 40% of total welding.
[0026] After completion of inside welding, robotic welding gun gives signal to PLC. (14). Then PLC. (14) unclamps and actuates the moving fixture (8) to move away from the indexing fixture (5). After that a spatter guard (15) is brought forward to safe guard disengaged moving fixture (8) from welding spatters during further welding actions. In short, the moving fixture (8) disappears from working zone. Now indexing fixture (5) is indexed to a second desired position for completion of remaining welding. Robotic welding gun (13) resumes welding after receiving confirmation signal from PLC (14) for moving fixture (8) disengagement. Indexing fixture (5) moves in synchronization with robotic welding gun (13) to complete remaining welding run for example 60 % of total welding. Once all welding is completed by robotic welding arm (13), it gives signal to PLC. (14), which further triggers pneumatic clamps to unclamp the assembly. Then the welded assembly is unloaded by operator.
[0027] As per another embodiment of the invention, the moving fixture (8) may be operated by a pneumatic or hydraulic or mechanical or electrical or similar arrangements. The moving action may be in the form of sliding or lifting or equivalent action. Also, as an alternative to servo drive, indexing fixture may also be rotated by mechanical arrangements actuated by Pneumatic or Hydraulic or electrical means.
[0028] The above inventive welding equipment and method helps to gain additional accessibility during welding and able to weld complete assembly in a single run/set up. Manual activity of conventionally unloading the part from 1st welding stage and loading that part to subsequent welding stage is eliminated. Any possibility of dents & damages is eliminated due to reduced material handling Also, since the part remains in fixed or immovable position throughout its welding, the distortions due to welding are also minimized. This method improves aesthetics of welded parts and also quality of weld joint.
[0029] Although the invention has been described with regard to its embodiments, specific embodiments, and various examples, which constitute the best mode presently known to the inventors, it should be understood that various changes and modifications as would be obvious to one having the ordinary skill in this art may be made without departing from the scope of the invention. The scope of the claims should not be limited by the preferred embodiments set forth in the examples, but should be given the broadest interpretation consistent with the description as a whole. All changes that come with meaning and range of equivalency of the claims are to be embraced within their scope.
,CLAIMS:CLAIMS:
WE CLAIM:

1. A welding equipment (100) comprising a plurality of fixtures characterized in that at least one fixture is an indexing fixture (5) and at least one fixture is a moving fixture (8); and wherein one fixture moves away from other fixture during at least one of the predefined welding stage/s.

2. The welding equipment (100) as claimed in claim 1, wherein the moving fixture (8) moves away from the indexing fixture (5) during at least one of the predefined welding stage/s of welding method.

3. The welding equipment (100) as claimed in claim 2, wherein the moving fixture (8) is moved by a moving arrangement (6).

4. The welding equipment (100) as claimed in claim 3, wherein the moving arrangement (6) comprises a telescopic lifers (6) for supporting the moving fixture (8) and a pneumatic lifter cylinder (7) for moving the moving fixture (8).

5. The welding equipment (100) as claimed in claim 4, wherein the indexing fixture (5) is indexed by a servo driven rotating unit (2).

6. The welding equipment (100) as claimed in claim 5, wherein the moving fixture (8) and the indexing fixture (5) comprises;
locating means (9) for locating one fixture with other fixture;
clamping means (10) for clamping both fixtures (8,5); and
provision for clamping child parts (17) on fixtures (8,5).

7. The welding equipment (100) as claimed in claim 6, wherein the locating means is a locating pin (9) and the clamping means is a wedge clamp (10).
8. The welding equipment (100) as claimed in claim 6, wherein the actions of indexing, moving and clamping are controlled by a programmable logic controller (PLC) (14).

9. The welding equipment (100) as claimed in claim 6, wherein the welding equipment comprises a spatter guard, which is brought forward between moving fixture and indexing fixture to safeguard the moving fixture from spatters of welding done on the indexing fixture when the moving fixture moves away from the indexing fixture.

10. The welding equipment (100) as claimed in claim 6, wherein the welding equipment comprises an automatic/robotic welding gun (13) used for welding and is controlled by a programmable logic controller (PLC) (14).

11. The welding equipment (100) as claimed in any of the above claims, wherein the moving fixture (8) is operated by a pneumatic or hydraulic or mechanical or electrical or similar arrangements and the moving action is in the form of sliding or lifting.

12. The welding equipment (100) as claimed in any of the above claims, wherein the indexing fixture (5) is rotated by mechanical arrangements actuated by Pneumatic or Hydraulic or electrical means.

13. The welding method with the use of welding equipment (100) as claimed in claim 1, wherein the method comprises steps of:
a. loading of the child part (17) on the indexing fixture (5);
b. automatic clamping of the child part (17) on the indexing fixture (5);
c. indexing of the indexing fixture (5) to a desired position;
d. triggering of a pneumatic cylinder (7) by a signal from a programmable logic controller (PLC) (14) to move the moving fixture (8) towards the indexing fixture (5);
e. positioning of the moving fixture (8) with the indexing fixture (5) by locating the fixture (5) by locating means (9) and locking in place by clamping means;
f. loading of the child part/s (17) on the moving fixture (8);
g. automatic clamping of t child part/s (17) on the moving fixture (8);
h. receiving welding start command from the operator;
i. performing inside welding of the child parts (17) clamped on the indexing fixture (5) and the moving fixture (8) using an automatic/ robotic welding gun (13);
j. unclamping of the moving fixture (8) from the indexing fixture (5) and from the welded child part/s (17);
k. triggering of the pneumatic cylinder (7) by a signal from the PLC (14) to move the moving fixture (8) away from the indexing fixture (5);
l. bringing a spatter guard (15) between the moving fixture (8) and the indexing fixture (5),
m. performing indexing of the indexing fixture (5) to desired position;
n. performing remaining welding of said child part/s (17) on the indexing fixture (5) using the automatic/ robotic welding gun (13);
o. indexing of the indexing fixture (5) to convenient position for operator; and
p. unclamping and unloading of the welded child part/s (17) from the indexing fixture (5).