Sheaves are grooved wheels or pulleys used with rope or chain to change the direction and point of application of pulling force. There are many different types of products. Often, suppliers categorize sheaves by materials of construction. For example, some sheave manufacturers carry cast iron, machined steel, or stamped steel sheaves. Cast iron sheaves can provide from 30,000 to 65,000 pounds of tensile strength and are designed to withstand heavy side-loads. Belt slippage is reduced to maximize power transmission at full speed. Steel sheaves are lighter than cast iron sheaves, but not as strong.
Products without rivets or spot welds provide better strength, concentricity, durability and run-out control than stamped steel shaves. Machined steel sheaves are impact-resistant and made of bar stock materials. Sheave suppliers that categorize products by features or functions may provide V-ribbed sheaves with smaller belt and groove sections. These products provide smoother and quieter operation than other types of sheaves, and are designed to maintain surface contact with the belt in order to maximize power transmission. Selecting sheaves requires an analysis of product specifications, the type of belt or groove to be used, bore sizes and types, and estimated annual usage.
Product specifications include sheave length and height, maximum cable outer diameter (OD), maximum sheave OD, minimum bending radius, maximum sheave width, shaft diameter, maximum line tension, and pulling radius. Dimensions such as height, width, and outer diameter are measured in English units such as inches (in) or metric units such as centimeters (cm). Maximum line tension is measured in either pounds (lbs) or kilograms (kg). Pulling radius is specified by number of degrees. As a rule, smaller groove sections minimize distortion and increase the arc of contact. Sheaves that are designed for single grooves or double groove are commonly available. Both types are designed for specific belt sizes and cross sections and may have fixed, tapered or splined bored. Common groove styles include O, A, B and A/B. Belt cross sections include cross sections H, J, K. L, and M.
Applications and Industries
Sheaves are used in a variety of applications and industries. Hooked hangar shaves have a hinged yoke for the installation and removal of fiber optic cable. They can be tied off to guide a cable into a duct, or used with an alignment arm to facilitate cable removal. Cable feeding sheaves plug into a conduit, usually within a manhole wall, in order to guide the cable into the conduit regardless of the pulling angle. Sheave suppliers may also sell corner cable guides, heavy duty quad blocks, fiber optic hangar blocks, 3-sheave cable guides, fiber optic sheave mounts, and jamb skids.