Shackle Inspection

Shackles - Types and Safe Use 

Shackle Types

Shackle Applications

Applications

Shackles are used in lifting operations and static systems as removable links to connect (steel) wire rope, chain and other fittings. 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 systems.

Where are standard screw pin bow shackles commonly used?

  • Screw pin shackles are used mainly in non-permanent applications
  • Screw pin shackles are only used in height safety applications
  • Screw pin shackles are not really used in load bearing applications

Correct use of shackles

Correct use of shackles

Select the correct type and WLL of shackle and WLL for the particular application. If extreme circumstances or shock loading may occur, this must be well taken into account when selecting the correct shackle. Please note that commercial shackles are not to be used for lifting applications. 

Shackles should be inspected before use to ensure that:

• all markings are legible;

• the body and pin are both of the same brand and type; 

• the body and pin are both of the correct size;

• never use a safety bolt type shackle without using a securing pin;

• the pin, nut, cotter pin, or any other locking system cannot vibrate out of position;

• the threads of the pin and the body are undamaged;

• 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 WLL;

• never modify, repair or reshape a shackle by machining, welding, heating or bending as this will affect the WLL.

Select three correct answers that would be considered as best practice when using shackles?

  • The pin of a shackle must be the correct type and dimension to suit the shackles body
  • It is important to use the correct colour shackle when rigging.
  • The body and pin must not be distorted
  • The shackle must be rated. Unrated shackles are not allowed to be used in lifting applications.
  • Shiny stainless steel shackles that you buy from the flee market are always good to use in lifting applications as it gives the riggers a good image.

Correct Rigging Practices when using shackles

Rigging Shackles

When a shackle is attached to the top block of a set of wire rope blocks the load on this shackle is increased by the value of the hoisting effect.

Avoid applications where the load moves over the shackle pin; the pin may rotate and possibly be unscrewed. If moving of the load cannot be avoided, or when the shackle is to be left in place for a prolonged period or where maximum pin security is required, use a shackle with a safety bolt, nut and cotter pin.

Samples

The above images demonstrate some rigging applications that are correct and also outline the incorrect way of rigging with shackles. 

1. When choking a sling and using a shackle as the connecting point, ensure that the pin is not on the live line so that when the load is sling is tightened the screw pin does not get undone. 

2. When rigging a load that requires the use of two lifting points, ensure the use of two separate legs to the load rather than using one sling. This is because if the single use sling where to run to one side due to the load being uneven then the screw pin of the shackle could undo itself. 

3. Always ensure the two slings are attached within the bow of the shackle and not on the pin. A shackle has significat load reductions when slung sideways and is not seen as best practice. 


How to rig correctly?

  • Rigging two slings off a shackle pin
    This is not best practice as the shackle load bearing capacity is significantly reduced when rigged using more than one load bearing point on the pin.
  • Choking a wire rope around the load to be lifted with the shackle pin on the live load
    This is not ideal as the live line could undo the pin when the line is tensioned. The correct way would be to to have the bow of the shackle on the live line and the pin located within the eye of the sling.
  • Dee shackle are great for rigging more than one sling off
    It is important to rig correctly and that is why dee shackles are generally used with only one load bearing point and bow shackles are used to spread the load - have more than one load bearing point within the bow.
  • Unrated shackles are common in the workplace.
    Rated shackles must only be used when lifting equipment. It is not acceptable to use unrated equipment with rated equipment as you do not know when the unrated gear will fail. When rigging for lifting, only use rated equipment.

Shackle working conditions - Temperatures.

Temperatures

If extreme temperature situations occur, the following load reductions must be taken into account: Refer to image below. 

Cautions

The rating of shackles to EN 13889 assumes the absence of exceptionally hazardous conditions. Exceptionally hazardous conditions include offshore activities, the lifting of persons and the lifting of potentially dangerous loads such as molten metals, corrosive materials or fissile materials. In such cases a competent person should assess the degree of hazard and the WLL should be reduced accordingly

Load reductions applied when exposed to varying temperatures. 

To avoid damage and possible failure when using in shackles in varying abnormal temperatures, it is advisable to follow the above load reduction chart. 

Temperatures

  • Shackles that are used in "out of the ordinary conditions" such as in the antarctic, should have the WLL reduced.
  • The WLL of shackles are not really affected when being used above molten metal pots in the foundry.
  • In temperatures between 200 and 300 degrees Celsius, the WLL must be reduced by 10%
  • Shackles are amazing and are not affected by having additional parts welded on them.