Stroke Limitations

There are several considerations that may fix the Practical stroke limit of a cylinder such as mounting style, mounting attitude, column strength of the piston rod, etc. These will typically require help from Engineering. There are, however, Definite stroke limitations imposed by the basic design of tie rod cylinders. Because of the tube loading required to properly prestress (torque) tie rods, the following bore size cylinders are limited to the corresponding strokes in standard, cataloged construction. Should you require a cylinder with a stroke in excess of that charted in adjacent column, contact your us for information concerning changes in construction and dimensions.

Supports

Relatively long cylinders often require supports to prevent excessive sag or vibration which could severely reduce the operational life of the cylinder. Depending upon bore size and mounting style, it may be necessary to specify either an intermediate mount or a tie rod support bracket. If the cylinder selected has a fixed, non-centerline mount such as side lug or side flush, the type of support to select should be an intermediate mount. This additional mount provides support for the cylinder tube and support for the tie rods. If a pivotal mount such as clevis or trunnion is selected, a tie rod support bracket should be considered. When a long stroke cylinder, with a fixed centerline mount such as a front or rear flange is specified, some form of support should be provided. An intermediate mount is often the most convenient way of doing so. The chart in the adjacent column provides a guide for determining the need for an additional support. It should be noted that neither a tie rod support bracket nor an intermediate mount is designed to absorb the thrust of the cylinder. They provide support only.

Rod Column Strength

When considering a long stroke cylinder, it is necessary to select a piston rod size of sufficient diameter to provide the necessary column strength. If the Cylinder will be performing work on the pull stroke only (rod in tension), selection of the standard rod diameter for that bore size will provide sufficient strength for operation at rated pressure or lower. If, however, the cylinder will be performing work on the push stroke (rod in compression), careful consideration must be given to column strength. Factors are the stroke length, rod extension length, mounting style,mounting attitude, force potential and  rod end connection. The mounting class chart assigns a mounting class reference number that corresponds to the mounting style, mounting attitude and rod end connection of the cylinder selected. Referencing that number and the sum of the gross stroke plus rod extension (if any), the column strength chart indicates the maximum allowable force for each available rod diameter.

This table is for steel Rods only:

Mounting Classes

Most maximum stroke lengths will be limited by the mount type and the type of rod support in your application.  Please refer to the charts below to determine which class your cylinder falls under.

Fixed Mountings

Head or Intermediate Pivotal Mountings

Cap Pivotal Mountings