Instrument for measuring impact forces on low-level pallet trucks

Status:

completed 01/2010

Aims:

Almost 50% of all accidents involving pedestrian-propelled industrial trucks result in injuries to the feet. Injuries to the foot region caused by impact and overrunning can occur only when the operator is standing close to the truck. This scenario arises primarily during manoeuvring at a speed of approximately 1 km/h. A bump strip for foot protection, developed by a supplier of industrial trucks and funded by the BGHW (the German Social Accident Insurance Institution for the trade and distribution industry), is intended to prevent such accidents from occurring in the future. In this context, the Institute for Occupational Safety and Health (IFA) of the German Social Accident Insurance was to develop a test facility by means of which these bump strips and if applicable those of other manufacturers could be tested on site at the operator's premises. The results of this project may for example also be suitable for use in the "Fight the Risk" campaign.

Activities/Methods:

Guideline measurements conducted in advance of the project proper showed the loading to have no significant influence upon the impact force during manoeuvring. The limits of the instrument were specified as follows: when an industrial truck fitted with a bump strip impacts against a rigid object, the contact force at a travel speed of 1 km/h must not exceed 2000 N, and initiation of reverse travel must occur within a travel of 15 cm. The travel of 15 cm allows for the fact that during walking backwards, the heel of one foot/shoe impacts a rigid object (such as a pallet), whilst the other, which is in contact with the bump strip, is still forward of the first shoe by approximately half a shoe length. The forward shoe can therefore be pushed back further by approximately 15 cm. Under no circumstances may the contact force exceed 2000 N. In order to permit reproducible testing, measurement methods and instruments must be described. In a further step, measurements for evaluation purposes are conducted on site in a plant in which typical situations involving pedestrian-propelled industrial trucks are encountered. The results are to be considered during modification of the measurement methods/instruments if appropriate.

Results:

A large number of accidents involving pedestrian-propelled industrial trucks result in injuries to the feet. They occur as a result of the rear frame edge impacting against or running over the feet. Such accidents can be prevented, for example by the fitting of a bump strip to the frame edge. For the adjustment and evaluation of such a cut-out device, the AKM 150/2500 is employed. This is an impact force meter developed and constructed during the IFA project concerning an instrument for measuring impact forces on low-level pallet trucks. The meter enables all values of interest to the tester, such as travel speed, travel and force, to be measured, displayed and evaluated. The instrument was calibrated for pressure in the mechanics test bay at the IFA, and provides precise (measurement error ±1.5% of the final value) and reproducible results. In addition, the impact force meter was used beforehand for two months by staff of the materials handling and warehousing technology committee of experts for trials within plants, in which it proved effective. The AKM 150/2500 impact force meter provides the materials handling and warehousing technology committee of experts with a mobile instrument, complete with comprehensive instruction handbook, which in future will assist in the prevention of foot injuries during transport operations within plants involving pedestrian-propelled industrial trucks.

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