WCA September 2021

Products

Success for trampolines with balanced Swedish springs Lesjöfors customised tension springs have contributed to the success of North Trampoline’s Performer model. the company turned to Lesjöfors with a request for the development of a spring solution.

and there was an increasing demand for wedge anchors due to their benefits in ceilings and other applications. There was also growing awareness of the concrete screw and its faster installation time. By 2010, the use of the sleeve anchor was at around 70 per cent globally – a 20 per cent reduction compared to the previous decade. In the present day, innovation, technology and efficiency have led to an increase in popularity of the concrete screw, which provides a simpler method of installation by only needing to be screwed into a pre- drilled pilot hole. This reduces installation times while still providing good tension and shear values. The concrete screw is also suitable for “close to the edge” applications where the minimum edge distance is small and the screw will not produce excess expansion and pressure on the base material. The popularity of concrete screws is increasing in Europe, while the market is more mature in the USA, where brands such as Tapcon gave the screws a faster introduction. Overall, concrete screws account for approximately 20 per cent of the mechanical anchor market. Due to their efficiency and time-saving properties, Celo expects concrete screws to increase in popularity, and has developed a large range for all types of heavy-duty installation. They are supplied with ETA approval and are fire resistant. Celo Fixings www.celofixings.com When possible, the company uses Swedish subcontractors, such as Lesjöfors. Thomas Hagel, R&D manager at North Trampoline, commented, “The ease of having a partnership based on the same values as ours cannot be underestimated. “Competence, responsiveness and flex- ibility are factors that make us happy to recommend Lesjöfors to others.” Lesjöfors AB www.lesjoforsab.com

The company ships trampolines to 22 countries in Europe and has just started sales in the USA, with Australia to follow later this year. In the development process of the premium-class trampoline, North Trampoline put high demands on performance, quality and safety. The tension springs have a key function, and

“Lesjöfors has spring development in its DNA so once we were clear about the requirements of the springs, the journey to a well-balanced spring with high dynamics and a long lifespan was smooth,” said Henrik Berner, business develop- ment manager for Lesjöfors Sweden. North Trampoline develops its new trampolines in Sweden.

Mechanical anchors through the years While mechanical anchors have been in use for decades, the popularity of the dif- ferent types of anchor has changed. Celo, a family-owned company dedicated to the design and manufacturing of screws and fixings, has highlighted three different types of mechanical anchors, to compare their uses, advantages and popularity. concrete, as well as providing a suitable option in countries such as Chile and Japan, where seismic activity needs to be taken into account.

By the year 2010, other mechanical anchors – such as the wedge anchor – started to become popular, along with the use of chemical anchors. The wedge anchor provided a cheaper alternative to the sleeve anchor, due toway it is designed and behaves on installation. Unlike the sleeve anchor, the wedge anchor gets its hold from just a small area, with a short collar at the base of the anchor that opens as the anchor is tightened. It is this collar that makes it suitable for ceiling applications, as it can readjust in case of cracking from the pressure of weight. Wedge anchors are also typically thinner than sleeve anchors, reducing the time and effort needed when drilling a pilot hole. During this time, the rate of construction grew in places including the Middle East,

The sleeve anchor has always been the most popular form of mechanical anchor, providing a strong and reliable hold, and is commonly used for connecting structural and non-structural elements to concrete. The anchor has an expansion cone that expands the sleeve through its internal threading. As it is tightened it will expand against the base material, giving it a strong hold that distributes the load along the length of the embedment. The thicker width provides a higher shear resistance, making the anchors suitable for installations on walls. It is estimated that back in the year 2000, around 90 per cent of all fasteners in concrete were sleeve anchors. Their popularity was due to their versatility of being applied to cracked or non-cracked

❍ Celo’s mechanical anchors

FA 8/48

www.read-fastenersasia.com

September 2021