wriggler

A wriggler is a vibratory feeder or conveyor that uses rapid oscillation to move bulk material along an inclined or horizontal surface. Instead of relying on belts, screws, or gravity alone, it shakes the material repeatedly in a controlled direction, using inertia to advance the load incrementally. The motion is typically generated by an electric motor driving an eccentric weight or by electromagnets cycling on and off many times per second.

Wrigglers are especially common in foundries, aggregate handling, and chemical processing where fragile material, sticky powder, or finely graded particles need gentle handling. The shaking action breaks up compacted loads, prevents bridging in hoppers, and ensures material flows steadily into the next stage of production. Unlike a rotating screw conveyor, a wriggler does not crush delicate castings or crush-sensitive crystals, making it the preferred choice when product integrity matters.

The name comes directly from the motion itself: the material literally wriggles along the deck. Variants include tray wrigglers (flat horizontal platforms), inclined pan wrigglers (V-shaped troughs running at 30 to 45 degrees), and high-frequency electromagnetic wrigglers that oscillate 50 to 150 times per second. Motor-driven wrigglers typically run at 600 to 1800 rpm, with eccentric throw and deck angle adjusted to match the material's density, particle size, and required throughput.

Common problems include material degradation if amplitude or frequency is set too high, uneven discharge if the deck warps, and noise from metal-to-metal contact. Worn eccentric bushings or bearing play will reduce efficiency and increase vibration transmitted to the mounting frame. Sticky or cohesive materials may ball up if the deck surface is not tilted sufficiently or if dust and fines accumulate.

Wrigglers occupy a middle ground in material handling cost and capability. They cost less than bucket elevators, require less headroom than belt conveyors, and handle more delicate loads than pneumatic systems. They are also known as oscillating conveyors, shake tables, or vibrating trays depending on industry convention and application.