COMEUP Industrial Winch (Ver:03) - Manual (Page 8)

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For example, if a vehicle weighing 3,000 kg is winched up an incline by 100% on the marsh
road, the above formula would be used as follows:
Where Wt: 3,000 kg, S: 0.52 G: 0.71
RPF = (Wt X S) + (Wt X G)
= (3,000 kg X 0.52) + (3,000 kg X 0.71)
= 1,560 kg + 2,130 kg
= 3,690 kg of effect required to recover the vehicle.
Winching V.S. Hoisting. A pulling winch should not be used for lifting.
Please refer to our website to view our full range of lifting winches
A gradient of 10% is a rise
of one meter in ten meters
(High / Distance)
Surface Type Surface Drag (S) Gradient Angle ( ) Gradient (G)
Metal 0.15 5% 3° 0.06
Sand 0.18 10% 6° 0.11
Gravel 0.20 20% 11° 0.2
Soft Sand 0.22 30% 17° 0.3
Mud 0.32 50% 26° 0.44
Marsh 0.52 70% 35° 0.58
Clay 0.52 100% 45° 0.71
°
In recovery and loading the winch is used to pull something, the required pulling force (RPF)
can be calculated according to the formula:
RPF = (Wt X S) + (Wt X G) Where: Wt = The gross vehicle weight
S = The type of the surface to be traversed
G = The gradient to overcome
Securing Anchor Point
When choosing an anchor point, select a safe and firm point such as a tree, stump or rocks.
If using a winch to retrieve another vehicle, the rescue vehicle is considered the anchor point and
should be made secure.
The anchor point must be strong enough to hold the gross weight of the vehicle and be
positioned to keep the fleet angle between the centre of the anchor point and the wire rope
maintained less than 3°. Always use a tree trunk protector strap to prevent ring barking the tree
and damaged to the wire rope.
Required Pulling Force
You need a winch powerful enough to overcome the weight of your vehicle with the added
resistance caused by the obstacle, moving water, mud, snow, sand or on a steep hill.
As a general guide, you need a winch with a maximum line pull of at least 1.5 times greater
than the gross vehicle weight.
There are three factors listed that influence the line pull effect required to recover the vehicle.
The values and calculations in this section are approximate and are for reference only.
a). Gross vehicle weight
b). Type of the surface to be traversed
c). Gradient to overcome