Aerial work platform basket maintained level by leveling cylinder

Aerial Work Platform · 5th of 7

Aerial Work Platform
Leveling Cylinder

The invisible cylinder. Workers never notice it — when it works. The basket stays level as the boom swings from horizontal to 80°. But if it fails, the basket tilts, tools slide off the edge at 30 metres, and workers grip the railing instead of working.

85–180mmBore

≤300mmShortest Stroke

±2°Level Accuracy

Why Only 300 mm of Stroke Is Enough to Level a Platform Through 80° of Boom Travel

Leveling cylinder mechanism at basket pivot

The leveling cylinder mounts at the basket pivot — a short lever arm (typically 150–300 mm from the pivot centre). The basket only needs to rotate ±10–15° relative to the boom tip to compensate for the full boom angle range. Through the short lever arm, 300 mm of cylinder stroke converts to approximately 30° of basket rotation — more than enough to keep the basket horizontal across the entire boom operating envelope from 0° to 80°.

This makes the leveling cylinder the shortest-stroke hydraulic cylinder in the seven-product aerial work platform family (and comparable to the small excavator bulldozing cylinder #4 at 250 mm). But the short stroke creates a design challenge: the leveling adjustment must be precise. A 5 mm error in cylinder position translates to a 1–2° tilt at the basket — and a 2° tilt on a 2-metre-wide basket creates a 70 mm height difference between the two edges that workers can feel underfoot.

Korea Ever-Power manufactures the leveling cylinder with low-friction seals and tight positional tolerance as the fifth of seven aerial work platform hydraulic cylinders.

Technical Specifications

Parameter	Specification
Product	Aerial Work Platform Leveling Cylinder
Function	Adjust basket angle to maintain horizontal (±2°)
Bore	85 mm – 180 mm
Rod	50 mm – 100 mm
Stroke	≤ 300 mm (shortest in AWP family)
Max Pressure	30 MPa
Application	Boom lift basket leveling (articulating / telescopic)
Certification	ISO 9001 · EN 280 / ANSI A92 compatible

Mechanical vs Hydraulic Leveling — Passive Geometry or Active Closed-Loop

Mechanical parallelogram — no cylinder needed, but limited

Some simple boom lifts use a parallelogram linkage that keeps the basket level through geometry alone — no hydraulic cylinder, no sensor, no control system. This works on straight articulating booms but cannot compensate for boom deflection under load, thermal expansion, or wind loading. When the boom flexes under a full platform load, the geometric leveling is no longer accurate — and the basket tilts 3–5° from horizontal.

Hydraulic cylinder + inclinometer — active, accurate

An inclinometer on the basket measures actual tilt. The control system compares it to horizontal and drives the leveling cylinder to correct the deviation — continuously, in real time. This active closed-loop system compensates for everything: boom angle, deflection, load, wind, and thermal effects. ±2° accuracy across all operating conditions. Contact Korea Ever-Power for leveling cylinder specifications.

Leveling cylinder maintaining basket horizontal at height

Manufacturing Process

The compact 300 mm stroke cylinder — overall retracted length approximately 400 mm — is honed to Ra 0.2–0.4 µm. Chrome 50 µm (the leveling cylinder is mounted at the basket pivot, partially shielded from debris). Low-friction PTFE guide rings and polyurethane seals for smooth, stick-slip-free proportional response — the cylinder adjusts continuously as the boom moves, making micro-corrections that workers cannot perceive.

Every leveling cylinder is hydrostatic tested at 45 MPa and level-accuracy tested — the cylinder is installed on a test rig with an inclinometer, and the basket angle is measured at 10 boom positions across the full 0–80° range. The maximum deviation from horizontal must be ≤2° at every position.

OEM & ODM

What You Provide

Platform model, boom angle range, basket weight and dimensions, required level accuracy (±degrees), bore/rod/stroke, system pressure, leveling method (mechanical backup or full hydraulic), inclinometer interface, and basket pivot assembly drawing.

What the Factory Delivers

Compact leveling cylinder with low-friction seals, chrome plating, and mounting dimensions. Hydrostatic + level-accuracy test certificate. Seal kits. Browse the aerial work platform cylinder family and the Korea Ever-Power catalogue.

Workshop

FAQ

Does every aerial platform have a leveling cylinder?

Only boom lifts — articulating and telescopic types where the boom angle changes during operation. Scissor lifts do not need leveling (the platform stays horizontal by the scissor geometry). Mast lifts do not need it (the platform is fixed to a vertical mast). On boom lifts, the leveling function is standard equipment.

What happens if the leveling cylinder fails while workers are aloft?

The basket tilts to match the boom angle — workers feel the tilt immediately. A load-holding valve on the leveling cylinder prevents sudden collapse (the basket tilts gradually as the cylinder leaks, not instantly). The operator must stop boom motion and lower the platform to ground level for cylinder service. On platforms with mechanical parallelogram backup, the backup linkage limits the tilt to a survivable range even if the cylinder fails completely.

How does the inclinometer achieve ±2° accuracy?

A MEMS inclinometer on the basket measures tilt to ±0.1° resolution. The control system drives the leveling cylinder proportionally — small corrections, continuously. The ±2° limit is not the sensor accuracy (which is much better) but the allowable deviation in the safety standard, accounting for dynamic effects such as wind gusts and boom oscillation. Browse telescopic cylinders and forklift cylinders.