A hydraulic cylinder is mounted by attaching it at two points of the machine it’s creating linear force for. The rod end of the cylinder must be attached to the part of the machine receiving the force, i.e., the part of the machine you want to push on. The other mounting point is somewhere on the cylinder itself, usually the head or cap. When we describe the “mount” of a hydraulic cylinder, we’re talking about the part on the head or cap attached to the machine.
Hydraulic cylinders are mounted in either a fixed or pivoting orientation. A fixed mount, such as a flange mount, is ideal for applications where the load moves along the center line of the cylinder; that is, when there is no misalignment or movement through an arc. An example of a fixed mount would be on a hydraulic press. Mounting a press cylinder with a full cap flange ensures the entire cylinder is supported in compression along its center line, which is ideal. Fixed mounts are permanently bolted to the machine, and move only when repaired or replaced.
Hydraulic cylinders with pivoting mounts are used where they’re required to move through an arc, such as a boom on an excavator. Pivoting mounts require them to pivot from the rod end as well as the cylinder itself. The vast majority of pivoting mounts do so from the cap end, providing maximum range of motion, such as the fixed clevis or cap trunnion mounts. Pivoting mounts are attached to the machine with pins in the case of clevis or eye mounts, and bearings in the case of trunnion mounts.
Regardless of mounting style, the rod side of a cylinder also needs to be attached to the machine. Although sometimes the rod treatment is welded on, such as a cross tube, most rod attachments are threaded on. The rod itself has a male or female thread, and the clevis, rod eye, rod swivel or other treatment is screwed on. A detachable accessory allows easy serviceability of the cylinder, and it allows easy replacement of the accessory itself once it becomes worn.