Glossary of Terms

Ratchet

A ratchet is a mechanism that holds part of the load on a pulley, letting you pull and release with complete control. Ratchets make it much easier to hand-hold higher loads by only allowing the sheave to turn in the trimming direction. When you are holding or releasing the load, the faceted sheave grips the rope to reduce fatigue and give you more control. Also, ratchets make faster pulling possible because you don’t have to hold the full force of the rope while shifting your grip.

Roller bearings

Roller bearings have greatly increased bearing contact surface area over ball bearings. This increases the strength and load capacity, but can also increase friction. For the best combination of high-strength and low-friction hardware we use caged roller bearings.

Self-tailing jaws

A self-tailing winch allows the rope to be automatically and properly pulled and paid out. The "jaws" are a facing pair of clamping rings at the top of the winch drum with an angular shaped groove between them for the rope. The self-tailing jaws support a stripper arm for feeding the rope from the drum to the groove and paying out rope from the groove.

Set screw

Several parts use set screws that can be tightened and loosed via Allen wrench or screwdriver, making it easy for users to customize settings such as a Ratchamatic's® engagement tension, a pulley's shackle direction, or a hydraulic relief valve's threshold.

Shackle

A U-shaped bracket, the open end of which is closed by a removable bolt (shackle pin), used for securing ropes, chains, etc.

Sheave

A sheave (pronounced "shiv") is the wheel of a pulley with a groove along its edge for holding a belt, rope, or cable.

Sideplates

Sideplates are the outer faces of a pulley that hold the sheave (wheel) in place. Sideplates can be made of lightweight composites, Hardkote-anodized aluminum, stainless steel, or titanium depending on the load requirements of the application.

Sleeve bearings

Sleeve bearings (also known as full-contact, plain, bushing, friction bearings, or journal bearings), are cylindrical inserts that provide a low-friction layer for two surfaces to slide against each other, such as a pulley sheave turning on a journal. Sleeve bearings are excellent for very high loads as they distribute the load over a large surface. For lower loads, roller bearings or ball bearings are preferred because bearings that roll have significantly less friction than bearings that slide.

Static loads

Light to heavy loads that do not require frequent adjustment. Constant stress deforms certain materials, so strength takes priority over friction reduction in equipment designed for static loads.

Stripper arm (also called self-tailing arm)

The stripper arm peels the top wrap of rope off the winch drum as it is turning so it does not bunch up at the top. Winches without these require two-handed or two-person operation to manually strip the rope while turning it.