Types of Rigging Hardware
Rigging hardware is used to support and move heavy loads. It is vital to store and handle it properly to avoid damage or accidents.
Eye bolts act as anchor points for rigging configurations and come in a variety of sizes and materials. They include shoulder eye bolts for angular connections and straight eye bolts for straightforward applications.
Eye Bolts
Eye bolts are fundamental pieces of rigging hardware that create secure anchor points in a wide range of lifting and securing applications. They feature a screw thread and a large circular eye, which connects to a rope or a shackle for fastening. There are many different types of eye bolts, each with its own specific application. It is essential to double-check the size and rated capacity of an eye bolt before use, as putting too much strain on one can result in damage or a potentially unsafe situation.
Every eye bolt has a specific marking, usually located on the eye, that includes the manufacturer’s name and/or trademark, as well as the size and rated load. The working load limit (WLL) is also shown on the eye bolt, which should never be exceeded.
Before use, an inspector should check that the eye bolt is properly seated in the hole and aligned Rigging Hardware with the direction of loading. A washer or spacer can be used to put the plane of the eye in alignment with the direction of loading, but it must not exceed a single thread pitch in thickness.
Steel Nuts
Steel nuts are used alongside eye bolts to anchor a rigging system. They are available in a range of sizes and thread types. Some are electroplated with zinc, allowing for better corrosion resistance. They also come in different grades to suit specific applications.
Alloy steel is an incredibly strong metal that has been combined with various elements, such as manganese or chromium, to increase strength and help fight the brittleness associated with standard carbon steel. It can be further heat treated to further improve its mechanical properties.
Stainless steel nuts are a great choice for rigging equipment because they offer enhanced corrosion resistance. They can also withstand extreme temperatures without losing their strength or durability. The type of stainless steel chosen depends on the application, with 316 marine grade hardware being the best option for use in marine environments. Stainless steel nuts have a hex design that allows them to be threaded onto a matching bolt. They may also be galvanized to further improve their corrosion resistance. Some are tapped slightly larger to accommodate a lock washer, which will prevent the nut from unscrewing.
Rigging Hooks
Rigging hooks are attached to chains and ropes to lift and move large loads. They can come in a variety of sizes and styles, each designed for specific points of connection.
Clevis hooks, for example, have a U-shaped opening with a pin or bolt threaded through the cross-holes and an open hook to connect to the load. They are commonly used to attach to wire rope slings or chain slings and can hold a variety of objects, including cargo containers.
Foundry hooks have a wider and deeper throat, making them ideal for use in the high heat environments found in foundries to handle castings or molds. They can also be used with a crane to top load objects.
Slip hooks have a “grab” design to keep the chain from slipping off of the hook, and they often feature a latch to help ensure a loaded hook stays closed when it is under heavy pressure. Like other rigging hardware, sling and hooks must be rated for the weight load they can safely hold (Working Load Limit or WLL). Positioning swivel hooks are designed to rotate so that your rigger can align and position the hook onto the pick point before adding the load.
Spreader Bars
Spreader bars are below the hook lifting devices that are used to widen a load’s available rigging points during a hoist. They are a popular alternative to lifting beams because they offer the ability to lift a load Rigging Hardware from multiple attachment points. They also require less overhead clearance than a lifting beam and are often cheaper to rent.
A properly utilised spreader bar distributes the force of the load evenly across its lugs, which helps prevent unnecessary strain on the hook mechanism and compromises stability during a lift. This helps eliminate the risk of load tipping, bending, or spinning during a hoist.
As with any rigging device, it’s important to follow manufacturer guidelines and safety protocols when using spreader bars. The device’s manual should include assembly instructions, adaptor attachment guides, rigging requirements and proper lifting techniques. A designated individual should perform a visual inspection before each use and ensure the device is safe to use. If it’s deemed unsafe, it should be marked as “out of service” and inspected by a qualified professional before being returned to the rental company.
Pulleys
A pulley is a simple machine that can make lifting heavy objects easier. It consists of a grooved wheel mounted on an axle. A rope can be wrapped around it and when a downward force is applied it turns the wheel with the load and creates an upward force at the other end. This mechanical advantage can be multiplied by adding more pulleys.
A movable pulley is useful for moving objects as it can change the direction that the force is applied, but it still requires the same amount of force to move the object. A compound pulley system is the best for moving a load as it combines fixed and movable pulleys, providing a greater mechanical advantage.
Engineers have incorporated the mechanical advantages of pulleys into many modern-day devices, including cranes and block-and-tackle on boats. They can also be used with motors and other hardware to create complex machines that perform much work for a small amount of energy. For example, they can be used to power zip lines, bicycles, rock climbing devices and even window blinds!