Checking Clamping Force/Overtravel - Festo DNCKE S Serie Instrucciones De Utilizacion

DNCKE−...−S / KEC−...−S
6.4

Checking clamping force/overtravel

WARNING
Unexpected movement of components.
Injury due to impacts or pinching.
If the clamping force of the clamping unit is no longer sufficient, the movable parts of
the pneumatic components can cause uncontrolled movements.
Uncontrolled movements of the connected actuators can cause personal injury or
material damage. Frequent checking of the overtravel will increase wear, depending
on how often this is done.
• Perform a check of the overtravel only if the product is used as a brake.
The overtravel is dependent on the load and the environmental conditions: temper­
ature, oil on the piston rod, number of switching cycles, speed, mass, operating
pressure and control (diagrams è 14 Characteristic curves).
• The overtravel check in a dynamic brake test must be performed beginning with
the maximum possible speed in the application (the maximum permissible travel
speed must not be exceeded).
• The clamping force is checked from the rest position.
The specified test examples correspond to the maximum applications. Deviating applic­
ations (sloping mounting position) cannot be represented. The specific application
might have to be calculated and tested separately.
WARNING
Unexpected movement of components.
Injury due to impacts or pinching.
• Make sure that there is an equilibrium of forces on the piston of the drive cylinder.
Especially when the device is mounted vertically, there is a danger of the piston rod
extending suddenly when it is loosened due to the axial force (weight force).
Note
• Observe the following points:
– The test force (test pressure) must at least equal the force (pressure) in the ap­
plication or must be specified in the risk assessment of the application.
– The test force must not be greater than the maximum static holding force
(è 13 Technical data).
– The overtravel in the dynamic brake test must be less than the tolerable over­
travel from the application/risk assessment.
– The piston rod must not slip through during the test over a period of 60 s. Rem­
edy in case of slipping: Readjust the clamping unit (è 6.2 Adjustment of
the clamping unit).
44 Festo – DNCKE−...−S / KEC−...−S – 1511b English