Meijer Special Equipment complies with ISO 13284

Normal lift truck forks have the ISO 2330 standard, technical characters and strength requirements. But until now there has not been an ISO standard for telescopic forks.
This meant that every manufacturer of telescopic forks could define its own standards. As a reference MSE always used the ISO 2330 standard because safety and strength requirements of telescopic forks are not (any) different than the requirement for fixed forks.

At this moment now the ISO committee is working on the final draft for telescopic forks and it is expected to become officially within a few months.
From that moment on all telescopic forks will have to meet the ISO 13284 standard, fork-arm extensions and telescopic fork arms, technical characteristics and strength requirements. When we wrote this article the content of the new standard was not definite but nevertheless we will take a look at the headlines in the following article.

One of the most important demands in this standard is that the inner fork of the telescopic fork must meet the safety factor of 3. For example a telescopic fork with a capacity of 2500 kg on an LC of 600 mm must be able to handle a load of 7500 kg for 30 seconds on the same LC. When tested twice these forks may not deform. This practical test has to be carried out recurrently.

The frequency of testing depends on the manufactured forks. Safety factor 3 only applies to the inner fork, the demands are principally the same as the ISO 2330 standard for the fork arm.

The committee applies a different safety factor for the outer forks, safety factor 1.25, while the outer forks are a critical part also. When the outer forks are completely extended , the load will be divided over a small part of the outer forks. This part, which is called "overlap", is the extended fork length minus the stroke.

MSE has an overlap of minimal 300 mm and therefore it is not surprising that MSE also applies a safety factor of 3 for the external forks. Because why would we apply safety factor 3 for inner forks and safety factor 1.25 for outer forks?
Especially at some specific applications, for example the use of side loaders, a maximum load can occur without the side loader turning over. A situation like this happens when the mast of the side-loader is still against the frame and the telescopic forks are extended with load.

Next to the established safety factor, which is defined by the most critical section there are other important elements that have an effect on the safety of outer forks.
How materials are welded, the materials being used and the wear and tear are important elements as well.

When an external fork is being loaded, there will be least tension in the neutral line because there is no difference in length. It is therefore of high importance that the welding seam of the outer fork is on the neutral line. This way there is no tension in the weld which prevents it from cracking. The heel should be made so that it is able to absorb a large moment.

Safety is an important issue, but also the use of clean oil is an underestimated problem because many modern lift trucks operate with high-grade hydraulic components. In dusty places it is possible that dirt sticks to the oil film of the plunger rod, which takes it into the hydraulic system. In co-operation with the largest manufacturer of lift trucks in Germany and a well-established sealing manufacturer, MSE has optimalized its seals and wiper rings so that it is almost impossible for dirt to get into the oil circuit of the lift truck. This prevents malfunctions and therefore extra costs. Research has proven that mounting a special wiper ring is needed for a solid seal. By honing, the used seals will have a long life and therefore reduces the maintenance to a minimum.

The telescopic forks have to meet the correct measurements to maintain 100% synchronisation of movement, because a small difference in diameter produces an enormous defect (see chart 2). It is almost always that a load is not proportionally divided on the telescopic forks. Then the telescopic forks will still move simultaneously and it also improves safety when stacking at large height. With the new ISO 13284 standard the telescopic forks are becoming a more accepted product but ofcourse the details guarantee the safety and life of telescopic forks.