The details as to four German pile drivers are now available. The 50-m/kg
pneumatic pile driver (Druckluftramme 50-m/kg), the 200-m/kg
pneumatic pile driver, the 450-kg diesel pile
driver (Dieselramme 450-kg), and the percussion
atomization 500-kg diesel pile driver (Dieselramme 500-kg,
Schlagzerstauburg) can all be used in conjunction with
the model 39 field pile-driving frame (Feldrammgerüst 39)
described in the preceding article. The following summary
of information as to these four pile drivers is taken from
* * *
a. Technical Data
|Weight of monkey
||1 ft 5 3/8 in
||3 ft 3 1/2 in
||4 ft 7 in (max)
||7 ft 2 5/8 in
||105 per min
||54 per min
||56 per min
||50 per min (approx)
||3 9/16 in
||8 1/4 in
|Force per blow
||2 ft 10 1/2 in
||5 ft 1 in (closed)
||5 7/8 to 9 7/8 in
||9 7/8 to 14 1/8 in
||10 to 18 in
|Weight including clamps
b. Pneumatic 50-m/kg
This driver is suitable for pile driving in the construction of bridges up
to 8 tons capacity. For piles up to 8 feet 3 inches in length it can
be used on land or on a raft without the pile-driving frame, but for
piles of greater length it must be used in conjunction with the field
pile-driving frame (Feldrammgerüst
The main components are the stationary part, consisting of the
piston, piston rod and piston base, the moving weight (monkey) consisting
of driving block, cylinder and screw-in cylinder head; the
spring-loaded clamping device; the guide for use with the
field pile-driving frame (Feldrammgerüst 39).
The driver (50-m/kg) is of the fast-hitting type, and it attains
its high rate because the acceleration of the moving
portion is due not only to its own weight but also to
the compressed air operating downwards on an internal
flange at the base of the bore of the cylinder.
Air enters through a coupling (10)
(figure 1) on the piston base (8) and passes
through the passage into the annular
chamber. From there, the air enters
through the openings across the slide valve
into the chamber above the piston (6) and
lifts up the cylinder (5) and driving block
(7). At approximately 3/4 stroke the
slide valve reverses and cuts off the air
supply from the annular chamber. The air
above the piston then escapes to atmosphere
through the exhaust passages. The monkey
then falling under its own weight and the
force of the compressed air in the annular
chamber, drives in the pile.
Located in the air passage in the
base of the piston is an air filter (9) to
prevent the entry of sand or dirt into the
inside of the cylinder and on to the valve.
(3) Method of Use
The pile is laid out horizontally. The pile driver is
lined up with the head of the pile and attached to it
by means of the spring-loaded clamps. A bolt is then
passed through the two clamps and the foot of the pile
driver and the clamps tightened up.
After attaching the air hose, the pile driver and pile are raised by the four
erecting rods which are screwed into sockets on the frame, on the base of the pile
driver, to which the clamps are attached.
The pile and driver are held vertically by four men, and the driver set in
operation. Once the pile is firm, the erecting rods are unscrewed and driving
Two lengths of air hose, 24 ft 7 1/4 in and 49 ft 2 1/2 in are supplied. The
shorter length is connected to the driver and the longer one to the compressor.
c. Pneumatic 200-m/kg
This driver is suitable for driving piles in the construction of improvised
bridges up to 16 tons in conjunction with the field pile-driving frame either on
land or on a raft. It can be operated by an air compressor.
The main components are the stationary part, consisting of the base plate,
the piston rod end bearing, the piston base and the piston; the moving portion
consisting of the monkey block, the cylinder and screwed-in cylinder cap; the spring-
loaded clamps and the guide for use with the field pile-driving frame.
The driver is of the free-falling type. The monkey is lifted up by compressed
air, falls freely on to the base plate and gives up its kinetic energy to the pile,
after covering a stroke of approximately 1 yard.
Compressed air is admitted through the lubricator in the piston base via
the air passage into the bore in the center of the piston rod. Then the air reaches
the slide valve, and passes it into the chamber enclosed between the cylinder
head cap and the piston. The compressed air lifts up the monkey until the exhaust
port connects with the air passage of the valve mechanism; the chamber above the
slide valve will then be emptied of air. The compressed air on the under surface
of the slide valve forces the valve up and, in so doing, cuts off the further flow of
compressed air. The compressed air in the chamber above the piston escapes to
atmosphere through the exhaust port.
Owing to its momentum the monkey rises a little further and then falls
Since the piston base is of cruciform construction, the monkey contains
corresponding recesses. To prevent the monkey twisting in relation to
the piston rod, two keyways are arranged on opposite sides in which
the keys slide. The projecting bolts prevent the keys falling out.
There is a fine mesh gauze air-filter in the lubricator body in the air inlet
passage, to prevent entry of foreign matter, such as sand or dirt, into the interior
of the driver.
The keyways for guiding the monkey are lubricated by use of the grease gun
on the grease nipples.
(3) Method of Use
Slide the guide piece on to the foot of the mast. Lift up the driver by means
of the winch, fasten it to the guide, and then fix the guide by means of
the "U" band stop supplied with the driving frame.
Then fill up the lubricator and grease the keyways by means of the grease
gun and nipples. After thoroughly blowing through it, connect up the
rubber air hose.
At temperatures below +10° C (50° F), with
very moist air, a light oil is poured into the rubber air hose.
The driver is then raised to the top of the mast and again secured by the
stop. The pile is then raised by means of the winch and secured to the mast by
the pile guide (supplied with the driving frame). The driver is then lowered on to
the top of the pile and fixed to it by means of the spring-loaded clamps.
Unlock the pile driver by twisting the exhaust port collar until the locking
studs spring into the holes in the collar. Open the air-cock at the compressor, and
the pile driver will begin to work.
For transporting the 200-m/kg pile driver, the exhaust port collar must
always be turned as far as the stop after pressing in the locking studs so as to fix
the monkey, and at the same time protect the piston rod from receiving dirt through
the exhaust port.
d. Diesel 450-kg
In conjunction with the field-driving frame this driver is suitable for
driving piles in the construction of improvised bridges up to 24 tons capacity.
The main components are the piston with anvil, the monkey, the guide
tubes, the headpiece, the fuel tank, the trailer.
The diesel pile driver works on the two-stroke principle, i.e. an explosion
takes place on each hitting stroke. The required ignition temperature is reached
through the compression of the air trapped between the top of the piston (5) see
figure 2, and the monkey (4), by the falling of the latter. Shortly before the monkey strikes
the anvil (14), fuel is injected into the compressed air in the combustion chamber
and ignites itself and burns. The gases evolved by combustion lift the monkey
upwards clear of the piston so that the exhaust gases will blow away.
The monkey falls freely under its own weight, and its kinetic energy is used
in driving the pile and in compressing the air for the next explosion.
It is important to filter the fuel carefully to avoid choking the nozzle (8) and
prematurely obstructing the fuel pump (10).
All moving and striking parts must be well-lubricated. For the piston, the
necessary lubricant, good diesel motor oil, is added to the fuel in the proportion of
1 3/4 pints of motor oil to 1 gallon of fuel. All remaining oiling places are lubricated
with diesel motor oil.
(3) Method of Use
The pile driver is lifted up off its bogie trolley and fixed to the mast of the
driving frame. The clamp securing the monkey on its seating on the anvil is taken
off. The fuel tank is fitted and connected to the fuel pump (10) and the tank filled
up. The bowden control cable is fitted to the pump and the air in the fuel system
released by unscrewing the bleeding screw. The bowden cable control is opened and
the pump operating lever (12) depressed several times.
The pile driver is then raised, being secured in position by the "U" band
stop, (supplied with the driving frame) the pile placed in position and pile driver
The cable from the winch is then attached to the monkey of the pile driver
by a trigger hook and the monkey raised to the top of the driver. Pulling the
trigger with the lanyard allows the monkey to fall and start operating. The stroke
is controlled by regulating the amount of fuel injected, by means of the bowden cable.
e. Diesel 500-kg (see figure 3)
This driver operating with either the field pile-driving
frame (Feldrammgerüst 39) or the
tubular pile-driving frame (Rohrammgerüst) is
suitable for driving piles
in the construction of improvised bridges. It can be operated either on land or on
a raft by one noncommissioned officer and 12 men.
The main components are monkey (piston) with oil reservoir for
self-lubrication; cylinder, with fuel tank; base plate
and anvil; guide cheek plates; cradle and bogie, and accessories.
The 500-kg diesel pile driver (percussion atomization) operates as a
single-acting two-stroke diesel engine, i.e. an explosion and an
effective blow on every cycle.
The fuel is atomized in the combustion chamber. The method of
operation is as follows:
In falling, the monkey operates the knocker arm of the
fuel pump and approximately 0.9 ccm (on setting the
fuel pump control lever for heavy blows) is injected, at a
pressure of 1.5 atmospheres (22 lb per sq inch) on to
the spherical cavity in the top of the anvil. The monkey, the
lower end of which is shaped spherically corresponding to the
cavity in the anvil, crushes the fuel already injected so
that it is atomized and dispersed in the combustion
chamber, analogous to hitting a drop of water with a hammer.
The firing temperature results from the compression by the monkey of
the air trapped between the monkey and the anvil, which becomes so hot
that the finely atomized fuel ignites and burns.
Part of the energy generated by the descent of the
monkey goes to drive in the pile and the rest serves to compress
the air for combustion.
The gases generated by combustion throw the monkey upwards again. The
stroke depends on the amount of fuel burnt. The monkey falls freely
under its own weight. The amount of fuel is controlled by the
setting of the fuel pump control lever. The exhaust gases pass
out through four ports in the cylinder jacket.
The diesel pile driver is comparatively speaking insensitive to
differences in energy content of different gas and diesel oils
as well as blended fuels, and can thus operate with various
fuels. It is important to see that the fuel is well-filtered. The
monkey lubricates itself automatically.
(3) Method of Use
First of all, attach the piston-raising trip mechanism to the mast. With
the Model 39 field pile-driving frame the raising cable is simply
hooked on, but with the tubular pile-driving frame the cable must
be attached by means of U-bolt clamps. After that, the pile driver
is raised by another cable and attached to the mast by means of
the guide plates. The trip mechanism is then lowered to a
trip stop on the outside of the cylinder jacket which causes
the trip lever to engage a circular groove on the piston
through a slot in the cylinder. For transport purposes, the
slot is covered up, and there is also a safety screw engaging the
same circular groove as the trip mechanism.
Clean fuel is poured into the fuel tank through a filter funnel, and the pipe
line to the fuel pump opened by giving three to four turns to the cock spindle on
the top of the fuel tank with the square-ended key. The fuel pipe and pump are bled
of air by loosening the bleeding screw which must not be taken right out.
The monkey is raised by means of the trip mechanism almost to the top
of the cylinder. The piston-lifting eye-bolt is taken out and after the oil reservoir
has been filled up, replaced by the self-lubricating plug and valve. Normally
motor oil is used for lubrication, but at temperatures
under 0° C (32° F) a 1 to 1 mixture
of motor oil and petroleum is used.
The fuel pump-control lever is fitted and the fuel pump tested by hand by
means of a tommy bar, after first setting the lever to maximum output. The fuel
injected during testing is withdrawn from the bottom of the combustion chamber
using a hand syringe through a plug in the cylinder wall.
The pile driver is raised to the top of the mast. The pile is placed in
position and the driver lowered on to it, and the turnbuckles securing the base