Hydraulic cylinders in lifting equipment operate by converting hydraulic pressure into linear mechanical motion. They consist of a cylinder barrel, a piston, and a piston rod. When pressurized fluid is introduced into the cylinder, it pushes the piston, which in turn moves the piston rod. This movement is what lifts or moves the load. The force exerted by the piston is proportional to the pressure of the fluid and the area of the piston. The cylinder's design allows for controlled and precise lifting, making it ideal for heavy-duty applications where power and control are required.