22
Chain drive
Assembly and operating instructions
ELTRAL KS 30/40 EASY
7 Calculating the opening and closing force
Note!
º
With the formulae indicated below it is possible to determine the approxi-
mate force required to open or close a (smooth-running) window.
Possible snow loads are to be considered.
Note!
º
The application formula considers tilt windows, top hung windows, and
roof-lights only.
The maximum rated drive force is to be taken from the technical data you
will find in chapter „5 Technical data for 1 motor“ on page 19.
If the values you calculated exceed the max. allowed force, please contact
Gretsch-Unitas GmbH Baubeschläge.
For roof-lights and small domes
Calculating the drive force depending on the sash weight
P
F
g
= 5.4 x P
For vertically installed tilt or top hung windows
Calculating the drive force depending on the sash weight
P
F
g
= 5.4 x P x C / H
Calculating the drive force depending on the wind load F
W
F
K
= F
W
x A / 2
Calculating the drive force depending on sash weight and wind load
F= F
g
+ F
K
F, F
g
, F
K
= opening / closing force (N)
P =
sash weight (kg)
A =
window area (m²)
H =
sash high (mm)
C =
opening distance of sash (mm)
F
W
=
wind load
Wind loads depending on the
building height
height
F
w
0 - 8 m
500 N/m²
8 - 20 m
800 N/m²
20 - 100 m
1100 N/m²
> 100 m
1300 N/m²
