LEXICONMachine components
Hydraulic cylinder
Also called: Hydraulic ram, actuator
A sealed steel tube in which pressurised oil drives a piston and rod, converting hydraulic pressure into linear force — the mechanism that moves every arm, blade and bucket on a working machine.
What it does
Oil at 250–350 bar acts on a piston inside a honed steel barrel, pushing a hard-chromed rod out or drawing it back depending on which port is pressurised. Force is pressure times piston area, so a 120 mm bore at 300 bar produces roughly 34 tonnes of push. Cylinders are the reason hydraulic machines replaced cable-operated ones: they deliver very large forces in a compact package and hold position without a brake.
Why it becomes an object
A cylinder is a machined object in a world of fabrications — a precisely bored tube, a mirror-polished rod, a threaded gland, an eye or clevis at each end. That contrast between the rough exterior and the ground rod is the whole visual interest, and it survives retirement, which usually follows seal failure, rod scoring or a bent rod after an impact. Rods are chrome plated over hardened steel and stay bright; barrels carry the paint, scars and patina of the machine they served.
