WE HAVE ALREADY DISCUSSED IN EARLIER POSTS INDICATION THAT SLIP HAS OCCURED IN CRANKSHAFT AND EFFECT OF CRANKSHAFT SLIPPAGE
WE HAVE TALKED ABOUT HOW TO CORRECT THE SLIPPAGE IN CASE THE SLIP ANGLE IS LESS THAN 5 DEGREES. IN THIS POST WE WILL TALK ABOUT HOW TO CORRECT THE SLIPPAGE IF SLIP ANGLE IS MORE.
PROCEDURE :-
BEFORE STARTING OF THE METHOD MENTIONED BELOW, CON ROD AND MAIN BEARING OF THE UNIT SHOULD BE TAKEN OUT.
A) MAKE A BRACKET FROM MILD STEEL AND SECURE IT TO THE TOP FLANGE OF THE BED PLATE. THIS WILL ACT AS A BUTTRESS FOR THE HYDRAULIC JACK.
B) MAKE A METAL TANK FROM STEEL SHEET OF ABOUT 1 MM TO SURROUND THE SLIPPED SIDE OF CRANKSHAFT TO PUT DRY ICE FOR COOLING.
C) NOW IN THE FIGURE ABOVE WE CAN SEE THAT TWO JACKS ARE USED ON EITHER SIDE. THE ADVANTAGE OF USING TWO JACKS IS THAT CONTROLLED MOVEMENT OF WEB WILL BE TAKING PLACE. AND IF WEB MOVES FURTHER THEN WITH THE HELP OF OTHER JACK, THE WEB CAN BE BROUGHT BACK TO THE CORRECTED PLACE.
D) A CIRCULAR FALSE BEARING IS FABRICATED AND PLACED IN PLACE OF MAIN BEARING WITH A 3 MM COPPER PLATE TO SAVE THE JOURNAL. ABOVE ALSO A FABRICATED CIRCULAR KEEP IS PLACED.
E) NOW PLACE A HYDRAULIC JACK FROM THE TOP TO SECURE THE JOURNAL FROM MOVEMENT WHEN THE SIDE JACKS WILL BE PRESSURIZED.
F) NOW , A HOLE IS DRILLED IN CRANKSHAFT JOURNAL TO POUR LIQUID NITROGEN. IF CRANKSHAFT IS HAVING LUBE OIL HOLES THE PLUG THE LOWER END WITH COPPER PLUG AND THEN POUR LIQUID NITROGEN.
G) COOLING OF JOURNAL WILL SHRINK IT.
H) NOW APPLY HYDRAULIC FORCE SLOWLY TO MOVE THE JACK WHICH WILL FORCE THE WEB TO MOVE. WHEN THE TWO MARKS ON WEB AND JOURNAL MATCHES THEN STOP APPLYING PRESSURE.