Krooklok’s History & Designs


Updated: 4th October 2020

(*) – denotes updates see below for details.

I have tried to find as much information on the brand and the company(s) as I could, some of which may be subjective based on the tiniest pieces of information from the internet. I would be delighted if somebody could give me some more accurate details and I will acknowledge your corrections.

A ‘locking device’ was invented by a Hungarian lady Mrs Zaidener. On April 3rd 1964, an agreement was signed between Brown Brothers Ltd. and the Quistomic Company Ltd to give Brown Brothers Ltd. the sole worldwide selling and marketing rights to the device. That device was later christened “Krooklok” by Brown Brothers Ltd. and was manufactured by a subsidiary of Brown Brothers Ltd. called ‘Brown Brothers Engineering Ltd.’, based in Northampton(*). That “Krooklok” device would go on to sell over 10 million units worldwide and became a world wide brand name.

Johnson and Starley Ltd. who are still based in Northampton, UK which is a subsidiary company of Brown Brothers Ltd. who are the manufacturers of Air Central Heating systems and should not be confused with the ‘Brown Brothers Engineering’ who engineered the actual “Krooklok” (*).

The design was in effect a telescopic bar with a hook at each end that was linked around the steering wheel and the other end hooked either round the brake or clutch pedal. In the centre of the bar was a locking barrel that locked a sprung loaded ball bearing into a recessed top part of the bar. With the key locked design the telescopic mechanism couldn’t be extended to release from the steering wheel. This was a visual deterant to stop thieves driving of with the car. The design would stop the pedals from being depressed or turning the steering wheel. The thief would have to remove the lock before attempting to drive off, potentially exposing themselves to what they were doing. Let’s face it, security in the 60’s wasn’t great and these Krookloks exploded onto the market. This was not a little company release but advertising at top sporting events mostly car oriented, Formula 1, rallies and amateur classes of motorsport.

Advertising was quite widespread and appeared in many magazines and a number of football programs. The earliest advert I could find was from 1965 from the Halfords catalogue.

The cost was fairly hefty 47 shillings and 6 pence. That worked out at roughly £2.37 at the time. In todays money that is around £37.50 in modern day money allowing for inflation over the fifty odd years. The price wasn’t exactly at the cheap end of the market but was a substantial lump of metal to have in the car.

A selection of more adverts from the early days in the mid 1960s to the early 1970s just after UK currency decimalisation in 1971 where the prices show the new money GBP.

In 1968 it looks like Krooklok ventured across the pond to the USA and applied for and was granted a Patent for the “Krooklok”.

For the UK I cant find an actual date that they were stamped on the locks, but it looks to have been granted around 1966 or 1967 at the latest. On the back of the barrel section is the trademark and the patent numbers. The registered design for Krooklok is 914608.

On the left is my own personal Krooklok which was made before the patents were issued, making this a very early and rare example. On the right is a slightly later dated Krooklok with the granted patents applied.

Over the years the design changed. The first itteration was a metal bar with a vinyl sleeve at the lock end in order to stop the metal hook marking the steering wheel. This sleeve was a nondescript grey colour and not really visible when fitted. Again a picture of my own restored lock with the original grey sleeve.

From outside the vehicle the “visible deterrent” wasn’t very visible especially at night. After the feedback was noted Krooklok introduced a new improved bright red sleeve that replaced the grey.

Moving on around a couple of years, the red vinyl sleeve was added at the opposite end of the lock for the pedals. This was to give more visibility and to protect the cosmetics of pedals. Early models came with the carboard boxes. Later models came with the plastic packaging.(*) Then back to carboard again for later revisions of the product.

Much later variations replaced the the nice chrome lock tower with a matching red middle section. The design also took a distinctive “twist” (literally) and the “hooks” changed from the facing each other on the same plane, now they were being set at right angles. This was intended to make fitting easier and stop the twisting of the original design to make it fit. This twist was down to the fact that as safety improved on vehicles the pedal design and steering wheels made some fitting to some vehicles a little more awkward.

My Krooklok on the top with the polished chrome lock tower, and the latest design at the bottom. The red locking section didn’t last long and was replaced with a contrasting yellow locking section, but this was just a cosmetic change. The steering wheel end has also seen a further modification to add plastic wings at the side hook to make it even more visible.

The pedal end was simply double indented or punched both parts together on one side and not the other. As the material construction is hardened steel this seems to be adequate but not ideal. This design hasn’t changed over the years and was hidden with the later pedal sleeve cover mentioned above.

The locking design was quite ingenious with a simple spring loaded ball bearing. The ball bearing is then locked into one of a number milled recesses that matched the diameter of the ball bearing. My lock before and after the cleaning to remove 50 years of grime.

Sliding the center section out to allow for a generous length of adjustment makes a very solid clatter as the bearing lifts and is sprung back into the next hole. The unit feels very strong and sturdy once fitted.

As the krooklok became more popular a couple of years later the advertising was added to the car window which stated that the vehicle was protected by “Krooklok”. The design saw a few variations of a the window sticker design, size and colours that warned potential thieves of the fitted Krooklok. The design started with a simple red warning design to more eye catching multi colour designs.

As time marched on Krooklok made other products, like locking wheel nuts, wheel clamps & tow bar clamps.

The Krooklock success still continues today with other companies making similar designs with similar sounding names to jump on the band wagon. Companies like, Stoplock, Disklok, Autolok, Xlock etc. The designs vary from pedal to steering wheel locks, to the more common bar through the steering wheel design.

After all the years the “Krooklok” still remains a strong brand name that started and set the standards of third party vehicle security.

Click here for a link to my own Krooklok that I restored for my own vehicle. The best part is that this particular model is period correct for my ’66 Mustang.

(*) 4th October 2020

I have been in contact with a former employee who had worked for the company that manufactured, sold, and marketed the “Krooklok” worldwide.

I am very grateful to them for giving me this valuable information which just isn’t on the internet – until now.

A huge ‘Thank You‘ to my source who had requested not to be named and I will of course respect that, always.