LW.A

Vibration-damping levelling feet

Features

ELESA vibration-damping levelling elements have been designed to damp vibrations, shocks and noises produced by moving bodies or non-balanced vibrating masses of equipment and machines which can cause:

• malfunctioning and reduction of the machine lifespan and/or of the adjacent ones;
• damage to operator's health;
• noise.

Technical data and guidelines for the choice

1. Basic data required:
• disturbing frequency: the frequency of the disturbing vibration produced by a on-duty machine. In general, it is obtained by the number of rotations of the engine [Hz=r.p.m./60];
• the load applied to every single vibration-damping element [N];
• the isolation degree required [%];
• the deflection value of the vibration-damping element under a given load [mm];
• the rigidity, that is to say the load that applied to the vibration-damping element produces a deflection of 1.0 mm [N/mm].
2. How to choose the vibration-damping element:
• with reference to the diagram for checking the isolation degree, intersect the disturbing frequency value with the isolation degree required (each isolation degree corresponds to a line in the diagram) and define the deflection [in mm];
• divide the load applied onto the vibration-damping element by the deflection value to obtain the required rigidity of the vibration-damping element;
• compare the rigidity obtained with the rigidity shown in the table and choose the vibration-damping element which presents the nearest value (lower) to the calculated one.
3. Check:
• the deflection of the vibration-damping element chosen can be obtained in the graph on the basis of the load;
• intersect the disturbing frequency value with the vibration-damping element deflection value in the diagram to obtain the isolation degree offered by the vibration-damping element chosen;
• compare the obtained value with the isolation degree required.
4. Example:
• Conditions of use: disturbing frequency = 50 Hz (3,000 r.p.m.); load applied to every levelling element = 4,000 N; a 80% isolation degree is required;
• diagram shows that with a 50 Hz disturbing frequency and an isolation degree of 80%, the deflection obtained is 0.6 mm;
• divide the load applied by the deflection obtained to define the rigidity required, which is 4,000/0.6= 6,666 N/mm;
• compare the rigidity value obtained (6,666 N/mm) with the values reported in the table. This value is within the rigidity value reported in the table for LW.A-120 (4,000 N/mm) and LW.A-160 (9,000 N/mm). Choose the vibration-damping element with the lower value that is LW.A-120.
• graph shows that LW.A-120 (4,000 N/mm) deflection is 1mm.
• by intersecting the deflection value with the disturbing frequency of 50 Hz in the diagram, the isolation degree obtained is 90%.

This value is even greater than the required one; your choice has proved to be correct.

 

 

• Put the base of the vibration-damping element under the machine and insert the stem through the hole (not threaded) in the frame of the machine (fig.1)
• Turn the square end of the stem to take the levelling plate in contact with the machine thus obtaining the levelling required. Then lock with nut and washer (fig.2)