Throughout the years, the simple concrete screw anchor has been extremely popular for their ease of installation which translates into reliability and practicality

Most mechanical anchors function via either a keying or undercut mechanism (achieved when a mechanical component is cutting/embedding into the post-drilled hole in the concrete) or by friction (achieved by an expansion component that pushes against the hole to hold the anchor in the hole). Keying is usually observed to be associated with higher performance when resisting tension loads. Screw anchors are also a type of anchor which function via a means of keying, as the ribs of the screws cut into the concrete. A large benefit of keying through the ribs of the screw anchor is the fact that they can be installed without concerns of an exact installation torque via a calibrated torque wrench. Unlike other traditional undercut or expansion mechanical anchors, screw anchors can be installed with an impact driver without controlled specific torque requirements.
 
As the screw anchor’s keying or undercutting into the concrete is established along the embedment length of the screw's spiral ribs, it also adds to a more uniform load distribution or transfer into the concrete substrate. This allows screw anchors to be designed and used at closer spacings and edge distances which are characteristics not typically associated to mechanical post-installed anchors. Screw anchors should not be dismissed as a light duty or temporary solution (often association made due to ease of removability).

While the humble screw anchor looks simple in design and may be perceived to be limited in distinguishing features and performance across the wide range of products available, a lot of research and development went into what Hilti are now proud to introduce as our fourth-generation screw anchor: the HUS4

With the HUS4 Hilti is bringing distinct new innovations to the market

1. The screw ribs have been re-designed, providing optimal load transfer and capacity
2. Achieves reduced friction during installation, proving much efficient and faster installation
3. New innovative HUS4 Max system - a hybrid solution utilising a chemical capsule, achieving loads exceeding or comparable to the highest performing products available
4. Can be used in diamond cored holes (refer to ETA approval)

We also noted feedback from the market and expanded the portfolio, incorporating new manufacturing techniques and bringing

1. Wider range of sizes and lengths - yes the Hilti screw anchor HUS4 is now available in 8, 10, 12, 14 & 16mm sizes
2. Available in the standard hex head, countersunk head and even a threaded head allowing for even greater flexibility for applications

Also needs to be mentioned, the new range still exhibits some of the best features of the previous generation HUS3

• Reusable with approved method using check gauge (lower friction in installation means the HUS4 should be able to be reused more than the previous generation HUS3)
• Adjustability
• Able to use the same hole incorporating HUS4 MAX system with the capsule
• Can be used in a non-cleaned hole (extra drill depth for non-cleaning is less than previous HUS3)

For more information on the new exciting HUS4 or the HUS4 MAX (hybrid system with capsule), please comment below or reach out to us through this LINK