A drag chain conveyor uses strands of chain that directly support the load and pull it along a track, rather than rollers that carry it. That makes it the answer for pallets with uneven bottoms, loads that will not ride rollers, and environments that are wet, dirty, oily, or hot. HOJ engineers drag chain into pallet conveyor systems alongside CDLR, transfers, and turntables.

Why the Load Bottom Decides the Conveyor

Drag chain suits items with uneven bottoms that are difficult to move on traditional roller conveyor, adapts to wet, dirty, and oily product, withstands high temperature environments, and offers reversible configurations for bi-directional flow.

In practice that means plastic pallets with molded feet, damaged stringer pallets, steel skids, drums on slip sheets, and hot castings all move on drag chain when they would hang up or damage rollers. In HOJ pallet systems, drag chain is specified for pallets with formed feet, irregular bottoms, or extreme heat, while CDLR conveyor handles general heavy loads in dirty environments.

Strand Count and Construction

Two-strand and three-strand configurations cover most pallet work. Three strands add center support for loads that would sag between two chains, such as large containers and long skids.

Construction is heavy: a 6 in by 7 ga formed steel angle frame with a 1-1/2 in by 3/16 in wall chain support tube, No. 60 or No. 80 single-pitch chain running on UHMW polyethylene chain guides, and diamond plate decking as standard. Modular drive, intermediate, and tail sections run continuous strands driven by a common drive shaft.

Capacity by Model

Frame widths are specified by strand centers. Two-strand accumulating models run 19-7/8 in to 49-7/8 in overall, and three-strand models run 37-7/8 in to 99-7/8 in overall with strand centers from 18 in to 48 in.

Accumulation Uses Lift Pads, Not Rollers

Zero-pressure accumulation on drag chain works differently than on accumulation conveyor built from rollers. Zone controllers sense product presence and activate lift pads that raise the pallet off the moving chains to hold it, then lower the load back onto the chains for release. Air requirement is 60 PSI recommended.

The chains keep running underneath. That is what allows a buffer of 10,000 lb loads to sit without back pressure ahead of a stretch wrapper or palletizer.

Unit Load Versus Bulk Drag Chain

The same term covers two different machines. Unit load drag chain moves pallets, skids, and large rigid containers. Bulk drag conveyors move loose material between processes, load and unload trucks and railcars, and feed production lines, with common use in agriculture and food and beverage.

If the application is grain, the facility itself falls under OSHA's grain handling standard, which carries its own requirements beyond general machine guarding.

Where It Sits in the Pallet System

Pallet lines mix conveyor types by load condition and function: CDLR for general heavy loads, drag chain for difficult bottoms and heat, plastic belt and mat-top for unstable loads, turntables and right-angle transfers for direction changes, and lifts and vertical conveyors for elevation changes. Integration points that drive the layout are robotic palletizers, AS/RS, stretch wrappers, and dock doors.

Guarding and Maintenance on Chain Drives

Sprocket wheels and chains must be enclosed unless they are more than seven feet above the floor or platform, and drives extending over other machines or working areas require protection against falling parts under OSHA power transmission rules.

Service items are chain tension, sprocket wear, and UHMW chain guide wear, since the guides take the sliding load the chains carry. Clearing a jam or working inside a guard is servicing under the lockout standard, so energy isolation and procedures apply.

Drag Chain Systems Through HOJ

HOJ specifies drag chain as part of a full pallet handling design driven by pallet condition, load weight, throughput, and accumulation needs, then handles controls, installation, and ongoing service with its own teams and a 70+ vehicle fleet.