Calculating The Maximum Loading Capacity (Payload) Of The Lch Spring Arm - Ondal ACROBAT LCH Operating Instructions Manual

8 Dismantling / Mounting in Case of Service
Figure 8: Calculating the maximum loading
capacity (payload) of the LCH spring arm
1505093, Edition 2012-05, Version 5
8.2.5 Calculating the maximum loading capacity (payload) of the LCH spring
arm
(See "Figure 8")
Sudden release of spring arm
The LCH spring arm 6 contains a powerful spring. When the end device
is dismantled, the spring arm can suddenly jump up and may cause seri-
ous injury:
• Before removing the end device (e.g. OR lamp), make sure that the
vertical lift of the spring arm 4 as described in
page 101
is restricted to the lowermost end stop (horizontal position).
The weight of an end device (e.g. OR lamp) acts as a lever on the spring arm from the
spring arm joint 1 up to the centre of gravity of the end device 2.
Maximum loading capacity of the LCH spring arm
The maximum loading capacity indicated corresponds to the maximum weight which can
be borne by a spring arm. For example, a maximum loading capacity of 176 Nm is indi-
cated on the rating plate. To check whether the spring arm can bear the actual load of an
end device, the actual load must first be calculated.
The total weight of the adaptation and the end device must not exceed the maximum load-
ing capacity (spring equipment) of the spring arms.
Possible loading capacities (spring equipment versions)
• 95 - 160Nm; 95 - 176Nm
• The spring equipment mounted is indicated on the rating plate on the top side of the
LCH spring arm 6.
Calculating the actual load
The actual load is calculated from the distance from the joint 1 of the spring arm to the
centre of gravity of the end device 2 multiplied by the weight of the adaptation and the
end device in Nm (1kg = 9.81N).
• The maximum loading capacity (payload) of the LCH spring arm 6 is 176Nm*.
* for spring equipment with a loading capacity of up to 176Nm. For other spring equipment
versions, the corresponding value must be used.
Configuration example
• Maximum load bearing capacity of the spring arm LCH = 176 Nm
• Length of the spring arm = 700 mm = 0.7 m
• Distance l between the centre of gravity of the appliance and the spring arm
= 300 mm = 0.3 m
• dead weight of the adaptation 8 and the end device (e.g. OR lamp) = 16 kg
Calculation of the maximum loading capacity
• Total length of the lever = 0.7 m + 0.3 m = 1.0 m
• Adaptation weight (bracket) in Nm = 5kg x 9.81N = 49.05N
• Weight of the end device ( e.g. OR lamp) in Nm = 12kg x 9.81 N = 117.72N
• Maximum loading capacity = 1.0m x (49.05N + 117.72N) = 166.77Nm
Evaluation
The calculated weight of the OR lamp with bracket 8 to be mounted of 166.77 Nm is be-
low the maximum load bearing capacity of the LCH spring arm 6 of 176 Nm.
84
WARNING
1
"Chapter 9.4.3" on
GB