Heavy-duty hoists used to move loads up to 40 tons are critical to heavy manufacturing, and engineers at Shepard-Niles, Montour, N.Y. (shepard-niles.com), have learned that paying attention to small engineering details results in dependable and safe manufacturing equipment. Their Class H3 hoists, for example, which meet all H1, H2, and H3 requirements, have a long list of safety and performance features.
For safety, the hoist has two brakes. The first, an electrical disc brake, uses forced-air cooling and can provide up to 150% of the torque generated by the lift motor. It also adjusts to compensate for brake-lining wear. The second is a mechanical brake which uses several discs yet imposes no resistance when hoisting. It reportedly has the largest brake-surface area and lowest psi in the industry. The drum is made of rolled steel or semisteel casting with flanges that protect against cable pinching. Grooves for wire rope are machined into the drum and establish minimum standards for pitch and depth. Hoists include enough rope to ensure two full turns of rope on the drum when it is in the full-down position. And the rope itself is actually made of wire with an independent wire rope center preformed and internally lubricated.