Customized 5 Stage Telescopic Hydraulic Cylinders

1. Pin Eye — Simplest Single-Pivot Mount

A welded ring (eye) at the cylinder end, through which a pin passes to connect the cylinder to a mounting bracket on the chassis or dump body. The pin eye allows rotation in one plane — the cylinder can pivot as the dump body rises. This is the simplest and most common mounting type for telescopic cylinders on dump trucks.

2. Clevis — Fork-Type Pin Mount

Two parallel lugs (fork) welded to the cylinder end, with a pin through both lugs and the mounting bracket sandwiched between them. The clevis is stronger than a single pin eye because the load is distributed across two shear planes instead of one. Clevis mounts are preferred for higher-force applications and larger bore cylinders where the pin shear load exceeds the capacity of a single-eye mount.

3. Trunnion — Mid-Barrel Pivot

Two opposed pins (trunnions) welded to the outer barrel, perpendicular to the cylinder axis. The trunnions sit in bearing saddles on the chassis, allowing the entire cylinder to pivot around the trunnion axis as the dump body rises. Trunnion mounts are used when the cylinder needs to swing through a large angular range — the cylinder body rotates rather than having a fixed base with an articulating pin eye at the end.

4. Cross Tube — Through-Barrel Pivot

A steel tube welded through the base of the outer barrel, extending beyond the barrel on both sides. The protruding tube ends rest in mounting brackets on the chassis, and the cylinder pivots around the tube axis. Cross tube mounts are common on North American dump truck and dump trailer telescopic cylinders — they provide a strong, simple pivot point and are easy to install (slide the tube ends into the bracket slots).

5. Flange — Bolted Fixed Mount

A flat machined flange welded to the cylinder end, bolted directly to a mating flange on the chassis or equipment frame. Flange mounts do not pivot — the cylinder is rigidly fixed. This is used in applications where the cylinder does not change angle during the stroke (vertical under-body hoists with straight-line extension) or in industrial/press applications where the cylinder axis remains fixed. Flange mounts offer the highest axial load capacity but no angular freedom.

Can I use a pin eye mount on a front-push hoist?

Yes, but only if the angular swing during the tipping stroke stays within the pin eye's articulation range — typically ±15–20° from the cylinder axis. Front-push hoists often require wider angular swing, in which case a trunnion mount at the base provides the necessary rotation range. If unsure, provide the starting and ending cylinder angle during the tipping stroke — the engineering team will confirm which mount type accommodates the angular range.

What happens if I use a pin that is 1 mm too small for the eye bore?

A pin that is undersized in the eye bore creates play (looseness) in the joint. Under dynamic load, the pin hammers against the eye bore with every tipping cycle — causing the eye bore to elongate (wear oval) and the pin to develop flat spots. Within months, the play becomes excessive and the mounting point fails. Always use the correct pin diameter matched to the eye bore — the standard clearance is typically 0.1–0.3 mm. Korea Ever-Power machines the eye bore to the specified pin diameter plus this standard clearance.

Can the base and rod end have different mounting types?

Absolutely — this is normal and common. A typical under-body hoist uses a cross tube at the base (for easy installation into the chassis cradle) and a pin eye at the rod end (for articulation with the dump body). A front-push hoist may use a trunnion at the base (for wide angular swing) and a clevis at the rod end (for double-shear load capacity). Specify each end independently when ordering.

Does the mounting type affect the cylinder price?

Slightly. Pin eye and cross tube are the simplest (lowest cost). Clevis requires machining two lug faces (slightly more). Trunnion requires welding and machining two opposed pins on the barrel (moderately more). Flange requires precision-machined mating surfaces and bolt holes (most). The cost difference between mounting types is typically 3–10% of the cylinder price — a minor factor compared to bore, stroke, and stage count. Choose the mount that fits your hoist correctly, not the cheapest mount. The same forklift cylinder range and aerial platform cylinder catalogue offer the same mounting flexibility.

We standardised on cross tube base with pin eye rod end for all our end-dump trailers — exactly what this mounting guide recommends. Ever-Power machines the cross tube to our exact diameter and length specification so it slides into our chassis cradle without modification. The pin eye bore matches our standard pin diameter within 0.2 mm — the fit is precise and there's no play. 50+ cylinders delivered, every mounting point dimensionally correct. The mounting type specification is just as important as bore and stroke — this guide explains it well.

Our front-push hoists swing through 55° of angular range during the full tipping stroke. We use trunnion base mounts to accommodate this swing — a pin eye would bind at 20°. Ever-Power welds the trunnion pins perpendicular to the barrel axis with ±0.5° angular accuracy — critical for our bearing saddle alignment. The clevis rod end distributes the push load across double shear. 5-stage, 5-inch bore, double-acting. 12 units, all mounting dimensions perfect. The trunnion/clevis combination is the correct engineering choice for front-push geometry — this page confirms it.

Ordered a replacement 5-stage for a dump truck — specified pin eye at both ends because that's what the original cylinder had. Turns out the base mount was actually a cross tube (I measured the pin eye bore of the rod end and assumed both ends were the same — they weren't). The replacement couldn't be installed because it had a pin eye where the chassis cradle expected a cross tube. Ever-Power replaced it at cost after I re-measured and provided correct dimensions. Four stars because the mistake was mine, but the lesson is real: always measure BOTH mounting points independently. Don't assume they're the same type.