High Clamping Force Hollo-Bolt for Structural Connections

Media

Working closely with structural engineers and steel fabricators, Lindapter identified the need for the larger M16 & M20 products to provide an increased clamping force that would be suitable for structural connections. Research and development led to the invention of the patented 5-part design, with an innovative washer that compresses during installation to significantly increase clamping force between the fixture and the hollow section. The superior performance minimises displacement (movement in the connection) at Safe Working Load for a more secure connection. The Hollo-Bolt HCF is designed to save steel contractors time and money and is exclusive to Lindapter.

The CE Marked fastener is recognised by the BCSA/SCI as a primary structural connection and is ideal for other safety critical applications such as securing steel canopies, roofs, glazing and cladding. The Hollo-Bolt offers a faster alternative to conventional SHS connection methods such as welding or through-bolting, enabling contractors to reduce construction time and labour costs.

Editor' Notes

Hollo-Bolt

The Hollo-Bolt is the original expansion bolt for structural hollow section and requires access to only one side of the steel section for a fast and cost effective installation. A typical connection is made by inserting the Hollo-Bolt into pre-drilled holes of the fixture and hollow section. As the bolt head is tightened, the cone is pulled up the bolt thread, causing the legs of the sleeve to expand until the cone locks the sleeve against the inner wall of the hollow section. At full tightening torque, a clamping action is set up between the fixture and the steel section to firm a secure connection. Once installed, only the head and collar are visible.

Hollo-Bolt HCF

The Hollo-Bolt is available in two versions: the original 3-part design for general hollow section connections and the larger sized 5-part High Clamping Force (HCF) version, for higher strength structural connections. Available as standard in sizes M16 & M20, the HCF version features a unique mechanism that compresses during installation to produce a typical clamping force over three times higher than the same sized product without the mechanism.

Hollo-Bolt HCF: Typical performance increase (Clamping Force)

As with any structural bolt, immediately after installation the bolt relaxes until a typical clamping force is reached. The typical clamping force of the Hollo-Bolt (HCF) is over three times higher than the same sized product without the HCF mechanism. This results in a more secure connection and a greater force that has to be overcome before displacement begins.

The blue curve in the graph opposite demonstrates the superior performance of the size M20 Hollo-Bolt HCF in contrast to M20 sized products without Lindapter’s patented HCF mechanism (i.e. the 3-part design in size M20).

The typical clamping force of the Hollo-Bolt HCF is over three times higher than the same sized product without the HCF mechanism.

Hollo-Bolt HCF: Typical performance increase (Displacement)

The significance of increased clamping force is shown in the graph below. When using the Hollo-Bolt HCF, displacement (movement in the connection) is minimised at Safe Working Load for a safer and more secure connection.

The blue curve in the graph opposite demonstrates the superior performance of the size M20 Hollo-Bolt HCF in contrast to M20 sized products without Lindapter’s patented HCF mechanism (i.e. the 3-part design in size M20).

The Hollo-Bolt HCF is optimised for safe and secure structural connections and is available as standard in sizes M16 & M20.