Driver safety first

100 tonnes are hard to imagine. An average blue whale is so heavy that hardly anyone has ever seen an entire one. OK, a typical diesel locomotive of the 218 series weighs just under 80 tonnes, and a fully loaded juggernaut is on the road with 40 tonnes. In the construction machine sector, designers can only smile weakly about such considerations. Whether for mobile cranes or, as in the current example, a piping and drilling machine from the specialist for special machines in Edewecht, Germany, Heinz Petry Maschinenbau GmbH, high machine weights are by no means uncommon. If the survival space for the operator of a machine with a machine weight of 100 tonnes is to be designed or even tested, some careful consideration is required at the manufacturer and the testing service provider.

Testing follows use

First of all, there is hardly any leeway when planning a cabin test. How the survival space for the driver or machine operator is to be measured, is specified in the globally valid standard ISO 3164. To put it briefly, here a dummy is defined all around the seat index point (SIP) which, even in case of deformation of the protective device, may only yield, i.e. be tilted, by a maximum of 15°. Here the SIP represents a geometric reference point, which results from the point of intersection of the upper body axis and the thigh axis on the vertical plane through the centre line of the seat. The same applies to the test for protection against falling objects (Falling Object Protective Structure, or FOPS for short) and the roll-over protection (Roll Over Protective Structure, or ROPS for short). Here it is specified in the ISO standards 3449 and 3471 how a corresponding test is to be conducted and what minimum forces or energies the safety structure must absorb. When planning the test, a hazard evaluation of the manufacturer is also included. For example, for the FOPS tests it must be defined whether the protection against smaller objects, e.g. bricks, small lumps of concrete or hand tools, is sufficient, or – as in the case of heavy construction and forestry machines – protection against heavy loads caused by boulders or trees must be provided. For the ROPS tests, at least an anti-trap protection for a driver secured with a belt must be achieved if the machine rolls over 360° at a speed between 0 km/h and 16 km/h on a hard surface with a maximum 30° inclination in the rolling direction. Here it is important to know that the mechanical connection, bearings or screwed connections between the machine itself and the cabin are usually also checked according to the regulations named.