Leantechnik SHB Series, Operating Instructions Manual

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6.5 Brake design
Designation
General
When selecting the brake, the nominal holding force must be
greater than or equal to the required holding force.
FNom ≥ Freq. [N]
Design for dynamic braking (EMERGENCY STOP)
As security, at least the weight of the load to be held
+ 100 % reserve must be provided for.
The greater the ratio of the nominal holding force to the re-
quired holding force, the shorter the stopping distance is (under
identical technical conditions)
The minimum holding force required can be calculated using
the following formula:
Freq.
= m x g [N]
0.5
Design for static holding (clamping)
As security, at least the weight of the mass to be held +20 %
reserve must be provided for.
The minimum holding force required can be calculated using
the following formula:
Freq.
= m x g [N]
0.8
The stopping distance / stopping time of the
load to be braked is strongly dependent on the following influ-
ences:
• Switching time of the control unit (signal processing)
• Switching time of the control valve
• Switching time of the brake
• Cross-section and length of cables
The greater the sum of the switching times the later
the deceleration of the load (due to longer
lasting acceleration). The stopping distance /
stopping time becomes longer (with constant holding force).
Designation
tKo
[s] Stopping time: Time
Signal interruption to standstill
of the load
V
0
[m/s2] Initial speed
V
max
[m/s2] Maximum speed
6 Correct use
1 Path
2 Speed
3 Axial force
β [°] Angular position 0° (horizontal) to 90° (vertical)
aB [m/s2] Acceleration of the downwards moving
load, depending on the angular position
av [m/s2] Deceleration
g [m/s2] Acceleration due to gravity (9.81 m/s2)
F
Br
[N] Braking force for dynamic calculation
F
req.
[N] Required holding force
F
Nom
[N] Nominal holding force (minimum holding force)
F
Ntot
[N] Rated holding force total (one or more
brakes)
F
max
[N] Maximum holding force
m [kg] Load mass
S
Br
[m] Braking path: path from beginning of deceleration
until the load comes to a standstill
S
Sys
[m] System path: path travelled by the
load until deceleration starts.
S
Ko
[m] Stopping distance: path from signal interruption
until the load comes to a standstill
t
50
[s] Brake switching time
tV
1)
[s] Valve switching time
(not applicable for Type 382.0 __._)
t
SV
[s] Control unit switching time (signal processing time)
t
Sys
[s] System switching time
tBr
[s] Brake braking time