As a manufacturing and engineering company, Columbus McKinnon places high value in STEM education – education encouraging students to pursue careers in Science, Technology, Engineering and Math. But, in recent years, STEM education has evolved into STEAM education, which aims to connect art to these areas of study to demonstrate how industrial products can contribute to creative artistic pursuits.
A perfect example of STEAM in a real-world application was initiated by our Channel Partner, American Crane. Artist, Janet Echelman, created an aerial art sculpture entitled “Skies Painted with Unnumbered Sparks” in Vancouver, Canada, that is suspended from the 24-story Fairmont Waterfront Building and the Vancouver Convention Center. Weighing more than 3,500 lbs., the sculpture is made of 145 miles of braided fiber and 860,000 hand/machine made knots.
To keep pedestrians safe as they walked below the sculpture, American Crane relied on CM Master Links and CM Master Rings. Known for their strength and durability, CM rigging products were perfect for this unique application with working loads limits ranging from 10,000 up to 86,000 lbs and a 4:1 design factor.
Without the use of heavy-duty equipment and engineering know how, such an impressive art installation would not have been safe or possible. This is just one unique example of how industrial technology contributes to making the world a more beautiful place.
A big thank you to our Channel Partner, American Crane, for sharing this unique application story with us!
This article is Part 2 of a 6-part blog series that will cover what professional riggers should consider when performing an in-depth alloy chain sling inspection. Today, we’ll discuss nicks and gouges.
When chain is used to lift, pull or secure materials, the outside surface of the links can come in contact with foreign objects that can cause damage. Nicks and gouges frequently occur on the sides of a chain link, which are under compressive stress, reducing their potentially harmful effects.
The unique geometry of a chain link tends to protect tensile stress areas against damage from external causes. Figure 1 shows that these tensile stress areas are on the outside of the link body at the link ends where they are shielded against most damage by the presence of interconnected links.
Tensile stress areas are also located on the insides of the straight barrels, but these surfaces are similarly sheltered by their location. However, gouges can cause localized increases in the link stress and can be harmful if they are located in areas of tensile stress, especially if they are perpendicular to the direction of stress. Refer to Figure 1.
Figure 2 shows nicks of varying degrees of severity. Reading clockwise, at three o’clock there is a longitudinal mark in a compressive stress area. Since it is longitudinal and located in a compressive stress area, its effect is mitigated, but good workmanship calls for it to be filed out by hand.
At about five o’clock there is a deep transverse nick in an area of high shear stress. A similar nick is located at six o’clock in the zone of maximum tensile stress. Both of these nicks can create a potentially dangerous escalation of the local stress and must be filed out with careful attention to not damage other parts of the chain link or chain. A nick that was located at eight o’clock has been filed out properly. Although the final cross section is smaller, the link is stronger because the stress riser effect of the notch has been removed. The remaining cross section can now be evaluated for acceptablity by measuring it and applying the criterion for worn chain. See the “Wear Allowances Table” below.