HYDRAULICALLY OPERATED EQUIPMENT

Last updated 1/16/03

Today's farm machinery uses hydraulics for a number of purposes, employing single- and double- acting cylinders and hydraulic motors to raise and lower equipment and power rotating mechanisms. Some machines, such as self-propelled combines and sprayers, have hydraulic motors to power the wheels.

The hydraulic system is operated by an engine-driven pump, typically located in front of the engine, and valves controlled from the operator's station. Hydraulic pressure on modern equipment is typically 2,500 psi, and the equipment is capable of supporting very heavy loads or exerting tremendous force.

Hydraulic hoses are coupled to the tractor with quick-connect couplers equipped with ball-type check valves. These couplers are intended to prevent damage to the hoses and contain the hydraulic fluid in the event towed equipment is accidentally separated.

Do not depend on the hydraulic system as the means of lifting nor supporting equipment during a rescue. Hydraulic systems are notorious for leaking down with the tractor running and especially with the engine shut off The fluid leaks may be external or internal resulting from wear or malfiinctions. This means that the supported load will slowly be lowered. If a hose ruptures, the load will drop suddenly and without warning. A more immediate danger is that the valves may not provide the sensitive or precise control needed, especially if the load is near the capacity of the hydraulic system. Still another danger is that the controls may be reversed from what is expected or the hydraulic hoses may be connected wrong. In this case, the equipment may go down when it is expected to go up.

The most likely dangers involving hydraulic systems are being caught in or crushed by hydraulically-actuated equipment. Occasionally, a person will be crushed by a dump truck bed while working on the truck's hydraulic system.

Leaks in the hydraulic system can cause injuries to the skin and eyes. A small stream of fluid from a pin-hole leak in a hydraulic hose can penetrate the skin. Whenever hydraulic fluid is injected into the body, seek medical attention at once to reduce chances of a dangerous infection. Burns are also a danger because the hydraulic fluid will become quite hot after a tractor or other machine has been operated for some time. Leaking fluid can also make surfaces very slippery, causing difficulty in using tools and also increasing the possibility of slips and falls.

Fire is always a danger when there are hydraulic fluid leaks. Keep a fire extinguisher ready for immediate use.

Injuries to Expect

Injuries may include hands or other body parts that have been crushed or sheared between equipment parts or pinned under equipment that fell

Rescue Procedures

Shut off equipment and support any raised loads with cribbing and jacks. Determine the nature and seriousness of injuries and plan the rescue.
Always assume the entire hydraulic system is under high pressure.
Treat hydraulic fluid as a combustible liquid. Minimize fire danger by eliminating sources of ignition. Have a charged fire hose and fire extinguishers ready for immediate use.
Do Not attempt to operate the equipment to free the patient unless experienced and familiar with the machine and its controls.
Sometimes it is easier and safer to dig the patient out when the equipment cannot be lifted. Securely support the equipment at all times during the rescue.
If equipment must be moved, securely support it with cribbing and jacks or other supports. Before relieving the hydraulic system pressure, make sure all components are securely supported. Moving the wrong control lever or relieving pressure on one part of the machine may result in movement of other parts.
If hydraulic pressure cannot be relieved by the controls, disconnect the hydraulic hose at the coupler on the tractor. (The couplers operate similar to those on air lines, except hydraulic hoses are equipped with ball-type check valves.) Pressure in the hose can be relieved by pressing or striking the check ball against a hard surface. Wear Eye Protection and be careful not to be burned by escaping fluid.
If couplings are not accessible, bleed off some fluid by loosening fittings on the rigid lines. Wear Eye Protection and other protective gear to prevent injuries.
Do Not Cut Hydraulic Hoses except as a last resort. Large amounts of fluid under high pressure will be released and sprayed over a wide area. This creates a fire hazard, makes everything very slippery and contaminates open wounds.
Treat any wounds caused by high pressure hydraulic fluid penetrating the skin immediately.