LEEA foundation part-8.pdf - Stress in Shackles A shackle is carefully designed so that the strength of the body and pin are approximately equal In

LEEA foundation part-8.pdf - Stress in Shackles A shackle...

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©LEEA Academy Foundation Step Notes Jan 2017 v1.5 119 Stress in Shackles A shackle is carefully designed so that the strength of the body and pin are approximately equal. In order to achieve this, the pin will be of a larger diameter than the body. The pin acts as a beam. If it is subject to a point load, it will be both in a condition of bending and of double shear. If the jaw is fully filled, so that the load is spread evenly over the full width of the pin, it will only be in double shear. A shackle pin is at its strongest when in a condition of double shear. For a point load, the maximum tensile stress occurs at the centre on the outward facing side of the pin. Standards assume that the pin will be subject to a point load, as this is worst condition, when calculating the pin diameter. Types of Eyebolts Dynamo Eyebolt Notes:
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©LEEA Academy Foundation Step Notes Jan 2017 v1.5 120 The Dynamo Eyebolt is the most basic in design and the most limited in use, this is because it only suitable for axial (directly vertical) lifting only. Effectively it is a ring sitting on top of the shank and has only a small collar. Although it is limited to axial loads, the eye is large enough to accept a hook of the same capacity. Dynamo Eyebolts get their name from the historical use to which they are put, being fitted by electric motor manufacturers to the tapped hole over the balanced lifting point of the motor. Collared Eyebolt The eye is blended to the collar in one plane. However, the eye is not large enough for direct connection to a hook and it is necessary to use a shackle for connection to other components. When used in pairs of the same capacity, the plane of the eye of each eyebolt must not be inclined to the plane containing the axis of the two eyebolts by more than 5°. In order not to over stress the shank, this alignment may be achieved by use of shims up to a maximum of half of one thread in thickness. A reduction in the maximum load that may be lifted is necessary due to the angular loading. This is far more drastic than is required with the Eyebolt with Link. Although in axial loading, size for size, Collar Eyebolts have a higher SWL, their capacity when subject to angular loads is far lower. Eyebolt with Link
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©LEEA Academy Foundation Step Notes Jan 2017 v1.5 121 This eyebolt has advantages over the other patterns of eyebolt when the loading needs to be applied at an angle to the axis and/or the plane of the eyes. Provided that the angle of the load to the axis of the screw thread does not exceed 15° they may be loaded in any direction to the full SWL rating. They have a small, squat, eye which is blended into the collar in all directions and a link is fitted to allow articulation and connection with other lifting components. The link is designed to accept a hook of the same capacity. Compared size for size with Collar Eyebolts, the SWL for axial load is lower. In all other arrangements, the SWLs are relatively greater than those of Collar Eyebolts when used in the same conditions. Unlike the Collar Eyebolt, the load can be applied away from the plane of the eye, as the link
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