Shackles are used in lifting and static systems as removable links to connect (steel) wire rope, chain and other fittings. A shackle has two main components: the body and the pin. The body can have the anchor shape (bow type) or a chain shape (Dee type). Each body shape can be used with a screw pin or a bolt-type pin, which can be used for different applications.
Screw pin shackles are used mainly for non-permanent applications. Safety bolt shackles are used for long-term or permanent applications or where the load may slide on the pin causing rotation of the pin. Chain or dee shackles are mainly used on one-leg systems whereas anchor or bow shackles are mainly used on multi-leg shackles.
Shackles are stamped with the WLL, manufacturer ID, traceability code and steel grade to specify the quality and safety of use of the shackles.
Ensure that the pin is correctly screwed into the shackle eye. Tighten hand-tight, then secure using a wrench or other suitable tool so that the collar of the pin is fully seated on the shackle eye.
Ensure that the pin is of the correct length so that it penetrates the full depth of the screwed eye and allows the collar of the pin to seat on the surface of the shackle eye. Incorrect seating of the pin may be due to a bent pin, too tight-fitting thread or misalignment of the pin holes. Do not use the shackle under these circumstances. Never replace a shackle pin except with one of the same size, type and make as it may not be suitable for the loads imposed.
Select the correct type of shackle and its Working Load Limit for the particular application. Should extreme circumstances or shock loading be applicable, this must be well taken into account on selecting the correct shackle. Please note that commercial shackles are not to be used for lifting applications. Make sure that the shackle is supporting the load correctly, i.e. along the axis of the shackle body centreline, avoid introduction of bending loads, unstable loads and do not apply overloads.
Shackles should be inspected before use to ensure that:
- all markings are legible;
- the body and pin are both identifiable as being of the same grade, type and make;
- the threads of the pin and the body are undamaged;
- never use a safety bolt type shackle without using a securing pin;
- the body and the pin are not distorted or unduly worn;
- the body and pin are free from nicks, gouges, cracks and corrosion;
- shackles may not be heat treated as this may affect their Working Load Limit;
- never modify, repair or reshape a shackle by machining, welding, heating or bending as this will affect the working load limit
Side loads should be avoided as the products are not designed for this purpose. If side loads cannot be avoided, the following reduction factors must be taken into account. In line loading is considered to be a load perpendicular to the pin and in the plan of the bow. Load angles in the table are the deviating angles from the in line loads. When using shackles in connection with multi-leg slings, due consideration should be given to the effect of angle between the legs of the sling. As the angle increases so does the load in the sling leg and consequently in any shackle attached to that leg.
When a shackle is used to connect two slings to the hook of a lifting device, a bow type shackle must be assembled with the slings in the shackle body and the hook engaged with the shackle pin. The angle between the slings should not exceed 120°. If symmetrically loaded the shackle may be used to the full WLL. To avoid eccentric loading of the shackle a loose spacer may be used on either end of the shackle pin. Do not reduce the width between the shackle jaws by welding washers or spacers to the inside faces of the eyes or by closing the jaws, as this will affect the properties of the shackle.