Mechanical Safety Support for the Linkage
The principle of not trusting the hydraulics but using a block, stand or mechanical lock when working under a raised linkage or implement. A hydraulic cylinder can leak, a hose can burst and the control lever can be moved by accident; you cannot stop any of these three possibilities with human strength.
The rule is simple: never go under any position where the load is held by the hydraulics. Lower the linkage; if it cannot be lowered, place a solid block or stand of sufficient capacity to carry the load, then release the hydraulic pressure and see that the support really takes the load.
- Stop the engine, switch off the ignition and take the key with you.
- If an electronic retrofit kit is fitted, also disconnect the kit's supply; the command can be given from outside the cab as well.
- On systems with wireless remote control, switch off the transmitter or press the emergency stop.
This second item is important: kits such as the LFT20, LFT54 and ELF-812 move the linkage command outside the cab. That is a convenience, but it also means an additional command path has been added that can be triggered accidentally. Cutting the energy before maintenance and repair now requires shutting off two sources at once.
Context in which this term is used: Converting a tractor hydraulic lever to electronic control