Self-locking hooks, also known as positive hooks or safety hooks, are used in all kinds of applications, from making stuff to offshore oil and gas. There are a lot of reasons why people switch from sling hooks or standard hooks to Self-locking hooks – all of them are about making it safer when you lift stuff.
Self-closing design
Hooks that close themselves As the name implies, self-locking hooks close themselves as soon as you put a load in the bowl of the hook and start to lift. Once they close, they won’t open again until you take the load out of the hook.
The self-locking hook concept was introduced as the BK model by Gunnebo Industries back in the 1960s, primarily to improve safety on construction sites where, up to that point, hooks were being rigged without any latch at all.
Highly robust latch
Lifting in construction is tough because loads vary. Gear takes a beating because lots of people handle the lifting gear and lift all sorts of things, which often results in damage to spring latches, like those on a sling hook. This either takes the lifting gear out of service, which can delay work on site, or if good lifting practices are not followed, people may use it without the latch, which is a hazardous lift. The latch on a self-locking hook is much more durable and will last much longer, and it will always be closed when under load.
Utilized in a broad range of applications
I could give you a long list, but here are three examples of places where people use self-locking hooks because they know they are safer:
- Construction: wire rope slings, chain slings, and as a connection point between a shackle (or hook) and a sling coming from an excavator.
- Industrial manufacturing: chain slings and we are also starting to see more hoists getting refitted with self-locking hooks.
- Offshore: used in forerunners / stingers, which is the line that comes off the crane on the offshore platform to either move loads around the platform or from a supply vessel to the platform.
We just launched the offshore galvanized BKLK self-locking hook. Working closely with end users in the offshore industry, we developed this hook as a game-changer in durability, and as proof of the exceptional performance of the hooks, they are also third-party type approved by DNV to relevant offshore standards. We’ve continued to innovate on the industry’s first self-locking hook we manufactured, even if the product today looks remarkably like the first one that came off the production line nearly six decades ago.
Self-locking hooks: the history
Back in the early 1960s, Karl-Axel Wahlström and Stig Lindgren made the first prototype, which they carved out of wood. They didn’t have 3D printing back then. They called it the ‘BK’ hook, which is short for ‘Byggnadskrok’. In Swedish, ‘byggnadskrok’ is a combination of the word ‘byggnads’, which means construction, and ‘krok’, which means hook. They patented the product and released it to the market in 1965.
Hot-dip galvanizing
Let me reiterate that our offshore range of self-locking hooks is hot-dip galvanized. We are producing more galvanized chain and rigging gear than ever before. We are providing products to EN ISO 1461, which is a hot-dip galvanized specification for coatings on iron and steel. Our products are manufactured and tested to, and above, the highest and most demanding standards globally to extend product life and enhance safety for both personnel and the environment. Galvanizing is the process of applying a protective zinc coating to prevent rusting. The benefits of galvanizing are that it provides a longer life span, protective coating with high impact and wear resistance, easy inspection, and lower maintenance costs.
In conclusion, while self-locking hooks are used in all markets, from industrial manufacturing to offshore oil and gas, there is an opportunity to bring the benefits that self-locking hooks provide to more job sites worldwide. People tend to choose a sling latch hook for convenience or cost, but with few exceptions the benefits of self-locking hooks far outweigh the drawbacks.
