Allied Construction Products, LLC www.alliedcp.com
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TM574173_HP4000_18feb
4.0 Product Overview
4.1 Description
The Allied Ho-Pac® is a hydraulic powered, vibratory
plate compactor and driver. It is designed for
mounting on mobile equipment with hydraulic booms,
such as rubber tired or track-type construction
vehicles. The boom mounted Ho-Pac reaches out to
work anywhere the machine can reach and allows
the operator to keep a safe distance from the work
tool.
4.1.2 Application and Use - Typical
The Ho-Pac is used for soil compaction. Applications
include backfill compaction, base course preparation,
finish surface treatment and embankment buildup.
The Ho-Pac can also be an effective sheet or pile
driver. Vibration energy is transferred through the
sheet or pile to the soil. Soils with 50% or more
granular content are “liquefied” by the vibration,
which breaks the skin friction, allowing the sheet or
pile to penetrate more easily. Further information is
available in the “Compaction Handbook”. To request
a copy, contact your local dealer or Allied’s Customer
Service. Ask for part number 103392.
4.2 Familiarization of Main Components
Fig. 4-1 Main Components
1. Dynamic Assembly
– Consists of the housing
weldment, eccentric mass, bearings and rubber
springs.
2. Suspension System
– Rubber Springs mounted
between the Top Frame and Dynamic Assembly
isolate the vibratory energy from the carrier.
3. Top Frame
– The Top Frame serves as the
connection point used to attach the Ho-Pac to the
stick / linkage of the carrier.
4. Control Valve
– A multi-function valve used for
controlling the motor. Benefits include optimized
operation with improved reliability of critical
components such as the motor and bearings.
NOTE
:
The valve is factory pre-set and requires no
further adjustments.
The control valve performs the following functions:
x
Flow regulator
– Protects the bearings from
excessive loads by limiting oil flow that can over-
speed the hydraulic motor.
x
Pressure control
– Protects the hydraulic
components from over-pressure. This is factory
pre-set at the maximum operating pressure plus
200 psi (14 bar).
x
Anti-cavitation circuit
- Controls deceleration of
the hydraulic motor and eccentric mass. Also
protects the motor against damage if the return
circuit is not set up with an unrestricted, free-
flowing open return.
x
Return line check valve
- Prevents reverse flow
to the hydraulic motor. Also provides a nominal
back-pressure to ensure the proper operation of
auxiliary valves, such as Allied’s AC40 and AC75
priority flow control valves.
4.3 Principle of Operation
The vibratory action and impulse force are generated
from the hydraulic motor turning the eccentric mass
at a high rate of speed. The strength of vibration is
affected by the rotation speed of the motor, weight of
the eccentric mass and the off-center distance
between eccentric mass and shaft.
The vibratory action and impulse force is transferred
through the attached compaction plate.
Efficient compaction of granular type soils is further
aided by the downward static pressure exerted by the
weight of the carrier pressing against the rubber
springs.
