Safety Handbook for Hydraulic Cylinders

The cylinder (or ram) operates much like the jack, but it is more versatile. Since the pump is separate, the cylinder can be used in various positions. By adding extensions and attachments, you can create a wide variety of hydraulic tools.

The saddle in the plunger serves two important purposes: it protects the plunger threads from damage and prevents deformation of the plunger’s end. Keep the saddle in place at all times. Do not thread attachments into the plunger and rely on the plunger threads for support.

The load must be transferred to the face of the plunger; the threads in the plunger may be stripped if overloaded. Like the bottle jack, the cylinder is a load lifting device and should never be used as a load holding device, especially when a person is going underneath the supported load.

Keep the Following in Mind When Using a Cylinder:

• Cylinder Base Safety:
  • The base of the cylinder should be fully supported. Where applicable, use a cylinder base plate for added stability. Do not weld or modify the cylinder to attach a base or other support.
  • The saddle on the end of the plunger should make full contact with the load. Try to move the load on the centerline of force to prevent side loading, especially with long-stroke cylinders.
  • Do not try to lift a load beyond the rated stroke. If you need to lift the load further, block it securely, raise the cylinder with a sturdy support, and continue the lift.

REMEMBER: Do not go under a load supported by a cylinder. After raising the load, it should be blocked.

Setup Considerations: The 80% Rule

When making hydraulic setups, examine the setup before using it. Look for ways to protect yourself, others, and your equipment.

Try to create the ideal setup. Since few things in life are ideal, following the 80% rule will lead to more stable setups and prolong the life of your equipment. The 80% rule applies to cylinder stroke and capacity.

Cylinder Stroke

The illustration at right shows two benefits of applying the 80% rule to cylinder stroke:

• Leaving distance between the stop ring and the bearing reduces side loading force, resulting in a more stable cylinder.
• Avoid damaging the stop ring by preventing the plunger from hitting the stop ring with the bearing.

Cylinder Capacity

Applying the 80% rule to cylinder capacity (tonnage) is essential because most loads are not lifted on their true center. This results in side loading of the cylinder. Allowing for a safety factor is the simplest way to compensate for the off-center characteristics of a one-point lift.