User manual

Appendix F: Mechanical Dynamic Loading
Dimensioning Example 8580
8580/8590 Vehicle-Mount Computer User Manual F-3
The ideal total spring constant should be dimensioned in such a way so that the natural fre-
quency of the system falls below the lowest excitation frequency.
All excitations with a frequency greater than 1.4 times the natural frequency would then be
dampened by a counter-phase effect. This is practically impossible if you consider that exci-
tation accelerations within the range of around 10 Hz to 200 Hz or more may occur.
Furthermore, the springs of the 8580/8590 would strongly deflect while static or visibly
swivel while resonating (blurred display).
Based on our experience, we have found that the natural frequencies of unsprung ground ve-
hicles lie between 15 Hz and 25 Hz. Although the elastic bearing does create an interfering
resonance, it can suppress high excitation frequencies to various degrees of success.
F.4 Dimensioning Example 8580
Example for dimensioning an elastic bearing with mounting bracket for mobile application.
The 8580 is screwed into a mobile position with a mounting bracket. Elastomer springs
should be installed between the back of the mounting bracket and the assembly surface in
the vehicle so that the depth can be adjusted.
The point of resonance for the spatial axis with the greatest deflection should be 20 Hz.
• Which elastomer springs are suitable?
• Which insulating effects can be expected for different excitation
frequencies?
Mounting example for table-top attachment with elastomer springs:
• 8580 with mobile mounting bracket, adjustable to 15 degrees
• 3 elastomer springs
• Diameter 30 to 40 mm, 20 to 30 mm high
• Natural rubber