Practical Installation Tips That Will Maximize the Lifespan of Your Vehicle Mount Computers

Inappropriately installed vehicle mount terminals (VMTs) stand the risk of impaired usability and will in worst case suffer early product failure. By learning from the following tips before deployment, you can avoid the biggest pitfalls and thus maximize the return of investment for your equipment.

Even though rugged computers are built to withstand both vibration and shock, which are by far the most stringent compliance requirements and indispensable in the transportation sector, there is still a risk of damages when the equipment is installed in forklifts or other vehicles, as the engine, tires, gears and motor simultaneously create different frequencies and amplitudes of vibration, also referred to as random vibration. The vibrations and shock levels generated by a warehouse truck depend on truck type, driving speed, floor condition and the type of wheels used; this means that the operating conditions that affect the reliability of computers installed in warehousing vehicles will always be unique, and could even vary within the same site. Appropriate installation can eliminate the effects of excessive shock and vibration in extreme environments and is the key to avoid computer failure.

Lower placement reduces shock and improves user ergonomics

As users drive over debris, stones or cracks in the floor, the truck slightly tilts sideways. The higher up on the forklift or vehicle the computer is placed, the higher the shock level from the sideway tilting gets. This means that in reach stackers, order pickers and other tall trucks where the VMTs are mounted hanging from the roof, there is a higher risk of inducing severe shock levels to the VMTs, leading to effects such as poor screen readability and fatigue-related damages and consequently to poor usability and, in some cases, early product failure. Thus, mounting the unit as low as possible in the driver’s cabin minimizes the level of induced shock, thereby increasing reliability.

Additionally, mounting the VMT at a lower point, for instance at the user’s waist height instead of over his head, is advantageous also from an ergonomic point of view – shorter reaching distance provides a comfortable and safe user environment, hence improving the user experience.

Rigid mounts increase steadiness

Where a unit is placed in the vehicle is not the only thing that affects its exposure to shock; what it is mounted to also has significant consequences. Using metal plates and long beams can cause unwanted amplification. To avoid this, the computers should be mounted on the sturdiest part of the vehicle and with appropriate mounting equipment. Rigid and stiff mounts help to reduce the risk of resonance in the installation which is usually the cause of costly vibration-related fatigue failures of parts and components.

Ensuring that the mounting equipment used is tightly installed, and that the parts are stiff and as short as possible, will further reduce the risk of vibration and shock amplification.

Vibration and shock dampers improve user experience

The use of custom-designed vibration and shock dampers together with the VMTs can reduce and in less severe cases eliminate most of the user-experienced effects from vibration, such as poor screen readability. However, dampers come in many forms and materials and it is critical to use a type that suits your specific environment, otherwise the dampers will not have the intended effect and can in the worst case even amplify the vibration.

First of all, for the dampers to be effective they shouldn’t have a resonance frequency that matches any of the vibrational frequencies created by the installation itself. This can be controlled by measuring the vibrational frequencies generated in the vehicle and decide on which dampers to use based on this information.

Second, it is important that the dampers are appropriately dimensioned and are made of a suitable material for the vibration isolation to be successful. The materials used for dampers come with different characteristics. A typical material used in passive vibration damping is natural or synthetic rubber. Natural rubber is usually preferable in environments where the temperature varies as it has a good damping coefficient in both low and elevated temperatures. Synthetic rubber compounds, such as silicone rubber, are often preferable when the vehicle is being exposed to direct sunlight as they provide better resistance to UV compared to natural rubber. However, synthetic rubber has the downside of low fatigue resistance and is in most cases a more expensive option than natural rubber. The geometrical dimensions of the dampers determine how well they absorb the shock and vibration energy, therefore the diameter and length need to be adjusted to suit the specific use case.

Air-filled tires with large diameters create less vibration and shock

The material and the diameter of the wheels used for the designated vehicle directly impacts the vibration and shock levels created by each wheel. Air-filled tires naturally have a higher damping factor as compared to solid plastic wheels which transmit almost all the vibrations and shocks to the truck and further to the VMTs. When it comes to the wheel diameter, a smaller diameter translates to a larger vertical displacement as the truck drives over cracks in the floor, a cause for increased shock levels. Consequently, considering the type of wheels used on the warehousing vehicles will also impact the durability of the installed VMTs. Selecting air-filled tires over solid plastic wheels and going for the biggest suitable diameter will have a positive impact on the lifespan of the computer. In unavoidable circumstances where trucks with solid plastic wheels are in use, it is even more important to follow the above listed installation tips to keep vibration and shock to a minimum.

Other factors impacting the lifespan of VMTs in logistic operation

Overall, a well-maintained warehouse floor, clear of debris and obstacles is beneficial not only to the equipment but also to the health of the drivers who often complain of joint pain in the knees as a result of excessive shock – especially in the case of trucks with solid plastic wheels where drivers stand throughout their work-shift.

Last but not least, let’s not forget that the impact force generated by the truck as it’s driven over cracks and obstacles is directly proportional to the driving speed. Therefore, driving at the recommended speed not only contributes to a safer work environment but also improved usability and longer-lasting equipment.

 

Author: Mahmud Nurein, Product Developer, JLT Mobile Computers

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