A Screw Pin Bow Shackle, also commonly called a Screw Pin Anchor Shackle, is a widely used connecting component in lifting and rigging systems. It features a bow-shaped body and a removable threaded pin, making it easy to assemble and disassemble in applications where fast connection is important.
This type of shackle consists of two main parts: the bow body and the screw pin. The bow shape provides a larger internal space than a chain or D shackle, which makes it suitable for connecting slings, master links, ropes, chains, or multiple rigging components when allowed by the application.
Because the pin screws directly into the shackle body, installation is quick and convenient. That is one reason screw pin bow shackles are often chosen for temporary rigging, repeated lifting tasks, and pick-and-place operations.
One key advantage of a Screw Pin Bow Shackle is speed. Since it does not require a separate nut and cotter pin, workers can install or remove it more efficiently during routine lifting operations.
Another advantage is versatility. The bow-shaped design allows more room for different connection configurations, especially where multiple sling eyes or rigging attachments must be connected at one point.
Screw Pin Bow Shackles are commonly used in lifting, rigging, material handling, and general connection work. They are especially suitable for jobs where the connection point must be opened and closed frequently.
However, they are not always the best choice for permanent or long-term installations. In applications involving vibration, movement, or conditions where the pin could rotate loose, a bolt-type shackle is often a safer option.
| Checklist Task | Safety Mandate | Technical Reason |
|---|---|---|
| Hand-Tighten First | Screw the pin fully into the shackle ear until the shoulder makes complete contact. | Prevents the pin from shifting under tension, which causes asymmetric thread loading. |
| Quarter-Turn Back | Back the pin off roughly 1/4 turn after tightening before starting a dynamic lift. | Prevents the pin from seizing or "locking up" due to body deformation under high stress. |
| No Pin Rotation | Never position the shackle so the running line or moving sling passes directly over the pin. | Friction from a moving rope can back the screw pin out during operation, causing complete failure. |
| Check for Spacers | Use washers or spacers on the pin if a narrow hook allows the shackle to shift laterally. | Centers the load on the pin, preventing severe bending moments on the shackle legs. |
