Pneumatic Hammer Flow Chart

[abknight@zzzzzz]

Is anyone interested in verbalizing the inner-workings of
the pnuematic hammer, or know of a good schematic on the
web?  It is difficult to verbalize mechanisms.  I imagine
there to be three vents on the cylinder wall.  An exhaust
vent at the bottom to prevent back pressure as the piston
falls and vacuum as it rises.  Actually I suppose this
"vent" is actually the opening at the bottom of the
cylinder  where the shank of the chisel meets the bottom
of the piston.  Another exhaust vent placed somewhat above
the top of the piston when it is at the bottom of its
stroke to prevent back pressue that would keep it from
rising.  This vent would be sealed by the piston as it
starts to rise off the bounce of the chisel shank.  This
vent would be placed to allow the piston some upward
travel and gain some momentum before the piston blocks it
with its passage.  And a supply vent further up the
cylinder wall, but not at the top, allowing it to be
sealed by the piston before the piston reaches the top of
its stroke.  The piston would then further compress the
air above it with its upward momentum.

Are chipping hammers or jackhammers different from small
carving hammers in their workings?