Powered Roller Conveyor Product

Overview

A powered roller conveyor moves unit loads — cartons, totes, trays — on a bed of rotating steel rollers. The modern form is the motor-driven roller (MDR) conveyor: instead of one large gearmotor driving the whole line through chains or a belt, each short zone contains its own motorised roller with the motor and gearbox sealed inside the roller tube. Zones run only when product is present, which cuts energy use, eliminates line-shaft guarding hazards, and allows zero-pressure accumulation — cartons queue without touching each other.

A typical line is assembled from 3 m frame sections, each carrying two or three zones. The Conveyor Frame provides the structure, each Motor-Driven Roller Zone provides tractive power and local intelligence, and the Control System tie the zones to the warehouse control system.

How it works

Each zone is 450–900 mm long, chosen so one carton occupies one zone. The zone's Motorised Drive Roller (MDR) is a standard 50 mm roller tube containing a brushless DC motor and a two-stage planetary reduction; output torque of 1–3 N·m at the tube surface moves loads up to about 50 kg per zone at 0.3–2.0 m/s. The remaining eight or so rollers in the zone are unpowered Idler Roller slaves, coupled to the MDR by elastic polyurethane Drive Belt O-ring bands seated in grooves near the roller ends. Two bands per roller-to-roller link give redundancy; a snapped band degrades traction gradually rather than stopping the zone.

The intelligence sits in the Zone Driver Card, a driver card mounted inside the frame channel. It commutates the MDR using the internal Hall Sensor feedback, monitors motor current for stall detection, reads the zone's Zone Photo-Eye, and exchanges two signals with the cards upstream and downstream. The accumulation logic is simple and entirely local: run the zone if my photo-eye is clear, or if it is blocked but the downstream zone reports clear. The emergent behaviour is zero-pressure accumulation (ZPA) — cartons advance and close up the queue, but never push on one another, because a zone holding a carton will not release it until the next zone is empty. Release can be singulated (one carton at a time, with a gap) or slug (the whole queue starts together).

Frame and rollers

The Side Channel Rail rails are roll-formed from 2–3 mm steel with hexagonal holes punched on a 75 mm pitch. Rollers carry a spring-loaded hex shaft at one end: compress the spring, drop the roller into opposing holes, and it locks against rotation — no tools, and any roller is replaceable in seconds. Frame Cross Member ties hold the rails parallel at the between-frame width (420–1,020 mm standard), Splice Plate joints connect sections, and Floor Support Stand H-stands set top-of-roller height, usually 450–1,200 mm. Curves use Tapered Curve Roller cones whose surface speed varies across the width, steering cartons around the bend without skewing.

Minimum roller engagement is three rollers under the shortest carton at all times, which fixes the roller pitch; flat-bottomed totes tolerate wider pitch than soft polybags, which need near-continuous support or a belted zone.

Controls and power

DC power is distributed along the frame by flat cable at 24 V (legacy) or 48 V, which halves current for the same power and allows longer cable runs; redundant Power Supply rectifiers feed sections of 15–20 zones each. The Network Gateway bridges the daisy-chained zone cards onto EtherNet/IP or Profinet, exposing each zone's status to the warehouse PLC for routing, release commands, and jam reporting from the Jam Sensor. Safety is conventional hardwired practice: an E-Stop Pull Cord along the line drops zone power through dual-channel safety Relay contacts. Because no roller can exert more than its motor's stall torque (and cards current-limit below that), MDR conveyor is markedly safer at nip points than line-shaft equipment, though EN 619 still requires the Finger Guard covers over band runs.

Variants and sizing

Belt-driven roller conveyor (a flat belt pressed under the rollers) and line-shaft conveyor (spools and urethane belts off a rotating shaft) preceded MDR and persist where long, simple transport runs make a single 2–4 kW gearmotor cheaper than one motor per zone. MDR dominates order-fulfilment systems because zones start and stop hundreds of times per hour without wearing clutches. Throughput is set by zone length and speed: a 600 mm zone at 1 m/s with singulated release passes roughly 3,000 cartons per hour. Heavier duties — pallets at 500–1,500 kg — use chain-driven roller conveyor with 60–89 mm rollers, a different machine class rated under CEMA standards.