The ISO 12140 standard applies to mechanically or hydraulically operated telescopic jacks, used for supporting and lifting agricultural equipments and agricultural machinery.
ISO 12140 defines the technical terms, indicates the functional, safety and reliability requirements, lists the information needed for marking, establishes the test procedures for certification of compliance and specifies the fitting, use, inspection and maintenance information.
The requirements of the standard that result in compliance are divided into 3 categories:
Crank effort: in respect of the ergonomic operation, the crank effort shall not exceed 225 N.
Corrosion protection: the standard specifies the resistance to corrosion requirements of the surface treatment requested by the client.
Mechanism: the rest position of the crank must not generate mechanical risks.
Overtravel: the mechanical assembly must withstand, at end of travel, an excess load on the crank equal to 150% of the maximum crank effort experienced at the rated dynamic load capacity.
Vertical static load capacity: the vertical static load capacity, as declared by the Manufacturer, cannot exceed 50% of the vertical static mechanical strength of the jack, measured experimentally.
Static side load capacity: resistance to the combined vertical and side load according to the parameters of the standard.
Ground pressure: with the exception of jacks equipped with wheel or other base configurations intended for specific use on special surfaces, the average ground contact pressure must be lower than 400 kPa.
Prevention of accidental ground contact: the jack must be installed in such a way that, when not in use, accidental contact or sticking into the ground are not possible.
Security in operating position: in the case of mobile jack installation, there must be security systems for locking operating position and permitting operation.
Hydraulically operated jack safety: the safety requirements for compliance with ISO 4413 must be fulfilled. In particular, a load maintenance system (e.g. block valve) must be installed.
Vertical dynamic load capacity and service life: the vertical dynamic load capacity, as declared by the Manufacturer, cannot exceed the value declared for the vertical static load capacity, and must be verified experimentally by passing the dynamic reliability test (performance of at least 250 dynamic cycles, observing the maximum effort at the handle indicated by the standards and applying the envisaged load).
The standard lists the information needed for marking the jack:
The standard establishes, rigorously and in detail, the experimental test procedures suited to measuring the mechanical strength for defining or verifying the acceptability of the requirements for compliance. The general instruction for fitting the jack on the test bench are provided as well as the specifications for performing every single test.
To this end, in collaboration with the University of Bologna, we designed and produced a test rig that allows us to test the extreme performance of our jacks and supporting wheels directly in our factory, subjecting them to the strength tests established by the International Organization for Standardization.
The jack is is mounted to the testing machine, fully extended. The vertical load is applied, increasing until it causes the axial structural collapse of the jack.
The purpose of the test is to measure the mechanical strength to determine the jack’s vertical static load capacity.
The jack is mounted to the testing machine, fully extended. A load direction is chosen, the side load increasing until it causes the structural collapse of the jack through deflection.
The test is repeated, changing the direction of loading, until the critical orientation characterized by the least strength is identified.
The purpose of the test is to measure the mechanical strength to determine the jack’s static side load capacity.
The static side torsional resistance class of the jack is also established in relation to the height of the grip point from the base of the test rig.
The jack is mounted to the testing machine and subjected to a constant vertical load over time. The intensity of the load is equal to the vertical dynamic load capacity that the Manufacturer intends to certify.
The jack’s crank mechanism is operated automatically, in such a way as to perform a complete dynamic cycle, characterized by extension to 65% of the useful stroke followed by retraction to the starting position.
The crank effort is measured continuously during operation, to verify that it stays within the limit established by the regulations. The dynamic cycle is repeated 250 times, so as to meet the service life requirement.
The purpose of the test is to meet the reliability target set by the service life, in compliance with the regulatory requirements, in order to certify the intensity of the vertical load applied as the vertical dynamic load capacity of the jack.
The jack is mounted to the testing machine, held in the air and subjected to an excess end-of-stroke operation test, both extending and retracting.
The operating command is maintained, at end of stroke, so as to apply an excess load to the crank of 150% of the maximum effort detected during the dynamic reliability test.
The test ends with structural verification, checking that the jack is still capable of bearing the vertical static load, and functional verification, checking that the jack can pass a 10-cycle dynamic reliability test.
This content is for the purpose of greater information and must not be used as a technical reference. For this, please refer directly to the standard: ISO /FDIS 12140:2013 (E).