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their grip on the pile during driving and certainly during extraction. Besides
causing a reduction in performance this can become a safety hazard. We define
the following wear limit:
Hard Jaw Wear Limit - 90% of all teeth on any hard jaw should make contact
Changing the Hard Jaws – Static Side
Remove the two Cap Screws that hold this jaw in place. Tap out the old jaw and clean/inspect the
clamp body seating area to ensure the faces are in good order. Slide in the new jaw and check that
it is a snug fit – the jaw should not move up and down. Fit the two Cap Screws and tighten using a
hexagonal wrench. Remember to install the washers on these screws.
Changing the Hard Jaws – Moving (Cylinder) Side
Release the Cap Screws that hold the Clamp Cylinder in place and remove the Clamp Cylinder.
Undo the two clamp supply hoses, carefully marking them to ensure correct re-assembly. Once
removed, unscrew the round Hard Jaw counter-clockwise and replace with a new one using a new
O-ring. Ensure the Jaw is fully tightened on the Clamp Cylinder piston rod so that the O-ring is no
longer visible. Inspect the bronze Guide Bush inside the Clamp Body whilst the cylinder is out –
check the grooves in the front area of the bush and the condition of the bore. Replace the bush if
badly worn.
Assemble the Clamp Cylinder back into the Clamp Body, fit the clamp hoses then fit and tighten
the Cap Screws using the hexagonal wrench. Ensure the clamp functions correctly after
completing the work.
g.
Inspect the rubber Sandwich Mounts (Elastomers) for wear or damage. Wear
is typified by splitting/tares. This usually occurs in the rubber adjacent to the
bonded steel plates and is usually a result of fatigue in the material over a long
period of time. Crazing/softening may occur but this is usually associated with
long term exposure to sunlight or exposure to petroleum based products. As a
general rule change the Sandwich Mount if any single tare or split exceeds 40mm
(1 ") or if the rubber has become contaminated.
h.
Check the overall condition of the Swivel Assembly. Check that the Lifting
Bolt and Nut (that are the centre piece of this assembly) only allow rotational
movement with minimal axial movement. Excessive axial movement will allow
the assembly to rattle around, make more noise and cause in turn more wear. If
the axial play exceeds 1mm it will be necessary to tighten the nut. To do this
remove the coil/spring pin with a punch and hammer, tighten the nut further and
drill and pin it in the new position.
i.
Check the condition of the boom Adaptor Bracket, Shear Pins, Spacers and
Bushes. The whole assembly should be relatively tight with minimal play in the
components. The bracket needs to be able to float a little from side to side – as
much as 5/10 mm is acceptable. The pins and bushes should however be little
more than a running fit – clearances of more than 0.5mm would be considered
excessive.
with the pile and 80% of all teeth should have points
with flats no greater than 5x5mm.
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