MSHA - Interactive Training - JTA Spiders -Table of Contents

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	Jaw Maintenance (2)
	Contact: Palmer.Melvin@dol.gov

The washers and nuts are removed from the back side of frame. A torch may be needed to remove. Ensure that all proper PPE is used during cutting operations. Make sure fire extinguisher is immediately available

Remove the retaining bolts and wedges

Remove the wedge/working platform from the jaw

Clear all non-essential personnel from the area

Essential personnel are the signalman and one mechanic to pry and guide the die

Non-essential personnel should move to the service truck

Pry the stationary die from the frame with the 6' pry bar

Ensure that the crane hook is centered over the jaw die

Remove the stationary die

Signal the crane operator to hoist (slowly)

If die does not move freely, release the tension and repeat the previous two steps

Guide the die out of the jaw by pushing or pulling hoist cables

Ensure that the die doesn't get hung up or snagged

Signal the crane operator to stop the hoist when the die clears the hopper

Attach a tag line to the bottom of the die when it clears the hopper

Ensure that you are not standing under the hoisted die

Drop the other end of the tag line over the edge of the hopper

Unhook lanyard from the body harness

Travel to the ground

Grab the end of the tag line

Ensure that you are not standing under the hoisted die

Signal the crane operator to resume the lift

Set the die on the blocking in a predetermined spot

Disconnect the lifting device from the die

2. Jaw Prep and Cleaning

Hose the inside of the jaw with water

Attach lanyard to the body harness

Install the wedge/working platform inside the jaw

Clean the machined surfaces with the wire wheel

Ensure that a face shield is used during this step

Check the machined surfaces with a straight edge

Grind the high spots off with grinder if needed

Ensure that a face shield is used during this step

Repeat the previous two steps until the surface is properly prepared

Get out of the jaw

Disconnect the lanyard from the body harness

Go to the under jaw belt

Slide down the belt to the bottom of the jaw

Ensure that the lower wedge bolts for both sides are tight

Inspect both lower wedges for debris and wear

Replace if necessary

Slide out from under the jaw

Replace lower wedges

Obtain tools

28mm socket

splined drive impact

28mm end wrench

3' Pry bar

Hammer

Remove the nuts and washers from the wedges

The washers and nuts are removed from the back side of frame and the pitman

A torch may be needed to remove. Ensure that all proper PPE is used during cutting operations. Make sure a fire extinguisher is immediately available

Remove the bolts from the wedges

Pry the wedge out with the 3' pry bar

Clean seat with the wire brush

Check seat

Clean the wedge with the wire brush

Install new wedge into the seat

Install with the lip up

Brush anti-seize on the bolts

Insert bolts through wedge and through frame

Put the nuts and washers on

Tighten nuts with spline drive

3. Flip the Stationary Die

Position the crane hook over the stationary die

The stationary and the moveable dies are different; check the part numbers for the correct die

Conduct a visual inspection of the lifting device

Clean die

Check die machine surface with straight edge

If old die is bent replace with new die; refer to the die replacement duty

Trim edge of die with torch if necessary to original dimension

Wear proper PPE

Attach the lifting device to the opposite end of the stationary die

Worn end up

Attach the tag line to the bottom of the stationary die (opposite of lifting device)

Ensure that all persons are clear from the lifting area

Signal the crane operator to hoist the die

Hoist the die

Center the die over the jaw opening

Signal the crane operator to stop hoisting

Attach lanyard to the hammer frame

Climb on top of the pitman

Remove the tag line from the die

Ensure that persons are not exposed to the suspended load

Lower the die into the jaw while guiding into position

Install the wedge/work platform into the jaw

Climb into the jaw and onto the wedge

Center the die

Ensure that the die is seated properly on lower wedges

Install the upper wedges into position

Install with the chisel side toward the die; this must be installed correctly

Brush on anti-seize onto the bolts

Insert the bolts

Install the washers and nuts

Washers and nuts are installed from the back side of frame

Remove the lifting device from the die

Reposition the crane hook over the moveable die

Tighten the nuts with spline drive impact

Remove the work platform

Remove lanyard from the body harness

4. Flip Moveable Die

Conduct a visual inspection of the lifting device

Clean die

Check die machine surface with straight edge

If old die is bent replace with new die; refer to the die replacement duty

Trim edge of die with torch if necessary to original dimension

Wear proper PPE

Attach the lifting device to the opposite end of the moveable die

Worn end up

Attach the tag line to the bottom of the moveable die (opposite of lifting device)

Ensure that all persons are clear from the lifting area

Signal the crane operator to hoist the die

Only the pre assigned person will give signals to crane operator

Hoist the die

Center the die over the jaw opening

Signal the crane operator to stop hoist

Move retractable lanyard to the stationary side (designated tie-off point)

Attach lanyard to body harness

Proceed to the stationary side of the jaw

Remove the tag line from the die

Ensure that persons are not exposed to the suspended load

Lower the die into the jaw while guiding into position

Install the wedge/work platform into the jaw

Climb into the jaw and onto the wedge

Center the die

Ensure that the die is seated properly on lower wedges

Install the upper wedges into position

Install with the chisel side toward the die; this must be installed correctly

Brush on anti-seize onto the bolts

Insert the bolts

Install the washers and nuts

Washers and nuts are installed from the back side of the pitman

Remove the lifting device from the die

Reposition the crane hook away from the working area

Tighten the nuts with spline drive impact

Climb out of the jaw

Remove the wedge/work platform

Lower lifting device to ground level

Remove the die lifting device from crane hook

Inspect lifting device

Inspect for cuts, nicks, gouges, cracks, excessive corrosion, heat discoloration, bent or any other defects

Store lifting device in proper place

Communicate with crane operator that the crane is done

Ensure that crane operator fills out vendor daily report form

5. Adjust Closed Sid Setting (CSS)

Slide under the jaw on the belt

Measure the current opening between the stationary and moveable jaw dies

Measure from die ridge to ridge; target measurement for the open setting is 6"

Tighten the adjustment wedges as needed to obtain the 6" OSS setting

Count the rotations (one rotation is equal to 1/16 of an inch) to adjust the wedges equally

Inspect the toggle rod and springs

Look for cracks

Replace immediately if cracks are found

Look for visible wear on the rod

Schedule replacement with site supervisor

Tighten the toggle rod nuts until knocking stops to obtain (16 3/4" overall spring length)

6. Work Area Cleanup

Gather and account for all tools

Put all special jaw tools back into the tool kit

Wrap all hoses up and put into the proper places

Scrap out old jaw dies with the loader

Conduct general housekeeping cleanup duties around the jaw

7. Jaw Start Up

Assemble all team members at the main power

Remove lock and tags

Follow proper company policy

Take a head count

Turn main power on

Stand to the side and turn face away from the switch

Push the start button

Listen for unusual noises

Knocking noises may indicate a loose toggle plate

Tighten the toggle spring if a knocking noise is heard

This step requires proper lock and tag out procedure; follow company policy

Remove barricade

Release the jaw crusher to the operator

Order new jaw dies

Notify the drill and blast personnel when job is completed

Conduct follow up during the next shift

Check die bolts to ensure that they are tight

Listen for knocking noises

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Jaw Maintenance (2)

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