OEM Single Acting Forklift Hydraulic Cylinder

Every lift function on a forklift — raising the forks, raising the mast, raising the carriage — uses a single acting hydraulic cylinder. Not because single-acting is cheaper (it is), and not because it is simpler (it is), but because single-acting provides an inherent safety characteristic that double-acting cannot: the cylinder cannot actively pull the load down. If the hydraulic hose, the pump, or the control valve fails while the forks are raised with a 2-tonne pallet overhead, a single acting cylinder holds that pallet in place. A double-acting cylinder, with its retract port open to drain, would allow the load to free-fall.

Korea Ever-Power builds this single acting cylinder as an OEM product in the lightest configuration available: 8 components, 6 kg reference weight, steel ball check valve for load holding, and no sprocket, oil pipe, or chain drive hardware. This is the bare-essentials lift cylinder for applications where an external sheave handles the chain drive, where the lowering valve is in the control manifold, and where the cylinder's only job is to push upward and hold.

This Product: 8-Component Design

Alternative: 27-Component Design

Forklift Mast — Replacement Cylinders

When an existing forklift's lift cylinder fails and the mast already has external sheaves and oil plumbing, the replacement cylinder only needs to provide the bare actuator function. The 8-component design drops into the existing mast channel at a fraction of the weight and cost of the 27-component integrated cylinder. This is the most common application for this product — aftermarket replacement on forklifts where the original cylinder is no longer available from the vehicle manufacturer.

Farm Equipment — Compact Lift Mechanisms

Livestock chute gates, grain bin unloading floors, seed hopper lids, and small agricultural platform lifts use single acting cylinders with steel ball check valves to hold position. The 6 kg weight and compact envelope fit the tight mounting spaces available on farm equipment where cylinder access for maintenance is limited and the service interval may extend to several years.

Industrial Lift Tables and Positioning Systems

Small hydraulic lift tables, tilt tables, and vertical positioning platforms in manufacturing plants use single acting cylinders where gravity provides the return force. The integrated steel ball check valve eliminates the need for an external check valve in the hydraulic circuit, simplifying the plumbing and reducing the total component count of the lift system.

If single-acting only pushes up, how does the cylinder retract — does it have a return spring?

No spring. The load weight provides the return force. When the operator opens the lowering valve on the control manifold, gravity pushes the load and carriage downward, which pushes the piston rod into the cylinder, displacing the oil back through the lowering valve to the reservoir. The lowering valve is a metering needle valve that restricts the oil flow rate — this is what controls the descent speed. Without a lowering valve (or with the valve closed), the check valve holds the oil and the load stays at height indefinitely. The short description mentioning a "spring" is a simplification — forklift lift cylinders use gravity return, not spring return.

How does this 8-part cylinder differ from the 8-part cart lift cylinder?

The architecture is identical — same 8 components, same steel ball check valve principle. The difference is application scope and dimensional range. The cart lift cylinder is produced in 4 fixed models with small bores (Φ40–Φ45), short strokes (120–155 mm), and high pressures (18–25 MPa) specifically for hand pallet trucks. This OEM single acting cylinder has no fixed models — bore, stroke, pressure, and mounting are custom-manufactured to your specification, covering applications from pallet truck size to large industrial platform size. If your application matches one of the 4 cart models exactly, order the standard cart cylinder. If any dimension deviates, order this OEM product.

Can this cylinder be used horizontally rather than vertically?

The steel ball check valve relies on gravity to seat on the conical bore seat. In a vertical orientation (port at bottom), gravity assists the seating force — the ball drops onto the seat naturally. In a horizontal orientation, the ball may not seat reliably because gravity acts perpendicular to the seating axis. For horizontal applications, specify a spring-loaded check valve (available as an upgrade option) instead of the gravity-seated steel ball. Alternatively, mount an external pilot-operated check valve in the hydraulic line if the cylinder must remain in the 8-component configuration.

What is the maximum bore and stroke available in the 8-component configuration?

The 8-component architecture is practical up to approximately Φ80 bore and 1,200 mm stroke. Above Φ80, the piston requires additional sealing elements (wear ring, piston seal) that are not part of the 8-component bill of materials — the cylinder transitions to the 25 or 27-component architecture to accommodate the larger bore's sealing and guiding requirements. Contact Korea Ever-Power with your bore and stroke specification for a recommendation on the optimal architecture.