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EMERGENCY FREE FALL:
The emergency free fall is used for a full release of a suspended load up to the maximum load capacity of the
Model M50 planetary winch. Upon activating the emergency free fall function, the load will drop and it must be
allowed to fall to its end travel without re-engagement.
FUNCTION OF THE EMERGENCY FREE FALL:
When the Model M50 planetary winch is actuated for emergency free fall, hydraulic pressure is channelled to
the clutch piston, causing the clutch piston to press against a series of springs and release the multi-disc clutch.
This effectively disconnects the cable drum from the gear train of the winch and the suspended load will drop. The
minimum load required to establish emergency free fall mode is 1,000 lb (554 kg).
CONTROLLED FREE FALL:
The controlled free fall offers positive down control of a load at selected speeds and can be stopped anywhere
on the way down. The controlled free fall is not designed, nor intended to lower the maximum load in a controlled
free fall. The permissible load is 30% of the maximum line pull capacity of the winch. Since the clutch release
pressure of the controlled free fall varies in accordance with the size of the load, a metering pump is utilized to
compensate for clutch release pressure variations.
FUNCTION OF CONTROLLED FREE FALL:
The controlled free fall has the same basic function as the emergency free fall with the addition of a metering
pump which regulates the different clutch pressure requirements during a controlled free fall. When the
controlled free fall is actuated, hydraulic pressure is channelled into the clutch piston, causing the clutch piston
to press against a series of springs and release the multi-disc clutch. When the clutch has been released, the final
planet assembly rotates with the cable drum, around a stationary sungear. A small hydraulic gear pump is splined
to the final planet hub. This hydraulic pump displaces hydraulic oil flow out of the free fall control circuit to
compensate for the difference in the clutch release pressure, which varies according to the actual lowering speed.
The faster the load is lowered with the free fall control, the faster the planet hub will cause the pump to turn,
increasing the displacement volume drawn out of the control circuit. When the free fall control is returned to neutral,
the hydraulic pressure in the clutch piston is vented and the free fall clutch is re-engaged by spring pressure.
COMBINED EMERGENCY AND CONTROLLED FREE FALL:
The emergency and controlled free fall can be combined for installations where both of these options are
required. Two separate controls must be used for this option and the operating criteria for both functions must be
adhered to.
IMPORTANT: Under no circumstances must the pressure in the free fall housing be permitted to exceed 10
psi (.7 bar). Excessive pressure will damage the main drum seals. Damage to these oil seals
will cause oil to leak between drum flange of brake housing or free fall housing.
CONTINUED
DESCRIPTION OF THE MODEL M50 FREE FALL
DANGER
RE-ENGAGING FREE FALL CLUTCH WHILE LOAD IS DROPPING
CAUSES SHOCK LOADS AND WILL LEAD TO CABLE FAILURE,
PROPERTY DAMAGE, SEVERE INJURY OR DEATH. INTERLOCK
HYDRAULIC CONTROL TO PREVENT RE-ENGAGING FREE FALL
CLUTCH WHILE LOAD IS DROPPING.
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