Gravity Roller Brakes

Urethane flat belts make excellent, inexpensive gravity roller brakes for declines on roller conveyors. Braking force can be adjusted by varying the number, width, thickness, tension and pattern of the belts as shown in the adjacent pictures.

By linking rollers together it is possible to significantly reduce the rate at which they rotate. Flat belts have a slight resistance to bending, but the primary source of braking is the nature of rollers themselves. The axis of a roller is never precisely at the center of rotation, so TIR (Total Indicated Readout -- a measure of radius variability) is always greater than zero. Since the a rollers' high and low points are almost always out of phase with its neighbor, linking them together produces a resistance to movement, wherein the belt is forced to stretch and relax with each rotation. This produces drag, which slows down roller rotation and box speed.

Brake belts will slow down boxes, tubs, cartons and plastic or aluminum pallets. Wood pallets can be braked also, but they should not ride on the belts, as nails or wood splinters, protruding from the pallet, can cut urethane belts.

Because of the numerous variables involved, (e.g., decline angle, average roller TIR, box weight, box speed, roller length, bearing type, box surface, belt stretch, thickness and width), it is difficult to determine the exact dimensions of the belts to use. Therefore, we provide a few samples, usually 1.5" (38mm) wide, for you to try. Based on their performance, you can zero in on the best size.

Flat Belt Brakes on Gravity Rollers
Four belts per roller

Flat Belt Brakes on Gravity Rollers
Two belts per roller