Patent applications for the Snap-Flat latch, PCT Publication Number WO2016/070235, have been granted in the USA (Patent Number 10,940,976) and China (Patent ZL 2015 8 0060162.7)
Patents have been previously granted for the Snap-Flat latch in Australia, France, Germany ,South Africa and UK, with applications in progress for Canada, India and Japan.
The latch was invented by Uniseg Products to address the problem of conventional over centre latches used on their Uniseg Container, being damaged while disengaged. The “Snap Flat” feature eliminated this problem. See www.unisegproducts.com for further information regarding the Uniseg Container.
The Snap-Flat latch also prevents the latch from accidently de-coupling, even when not properly secured in the over-centre position. This is a common problem with conventional over centre latches that can have catastrophic outcomes in some applications, such as when securing the roof of a pop top caravan.
Most Pop top and Hybrid caravans use 4 over centre latches to secure the pop top roof to the caravan, when the van is not being used or being towed. There are however several problems and safety issues that can occur with the style of over centre latches that are used on almost all Australian pop top / hybrid caravans. These include:
1. De-Coupling of the Latch
If the latches aren’t correctly secured into the over centre position or due to subsidence of the pop top’s canvas sides during towing, the latches may de-couple from the catches. This represents a potentially deadly accident if the roof lifts-up and blows away during towing. That is exactly what happened to this poor driver who’s pop top blew off while travelling along the Hume Highway in Campbellfield, Sydney. Fortunately, the drivers travelling behind were able to avoid colliding with the flying pop top.
2. Latch Failure & Corrosion
Pictured above is the style of over centre latch used on the vast majority of Pop Top Caravans. Their poor design & construction leads to several problems, including:
The thin pop rivets used as the pivot pins fail because of their diameter size and wall thickness (too small and too thin/ not ‘Construction Grade’),
The use of Pop Rivets also causes the latch to be stiff in operation from new and creates a potential for personal injury when the latch handle is left protruding at a 90 degree angle to the the body of the vehicle
The latch becomes difficult to use or inoperable due to corrosion or distortion and damage to the latch. There appears to be several causes including protruding latches being knocked, latches being over tightened and when collapsing the pop top.
The galvanised steel construction can result in corrosion quickly setting in. Given Australian’s love of the ocean and the coast, this seems like a poor choice of material when for a few dollars more stainless-steel fittings could be used.
3. Injury Caused by Protruding Latch
When the over centre latch is dis-engaged the latch T Bar can protrude and accidently gouge or snag the user. Some Pop Tops have latches installed at eye level that have resulted in significant injuries.
4. Damage to the Lifting Cable Mechanism
If all 4 x over centre latches aren’t correctly disconnected before trying to wind up the Pop-Top, damage can be caused to the Pop-Top lifting cable mechanism. This can typically cost anywhere from $200 – $500 to repair.
Solving the Over Centre Latch Problems with Pop Top Caravans
Frankly, we are surprised that $40 – 80K Pop Tops come installed with such poor quality over centre latches that can lead to such dangerous outcomes.
Uniseg Product’s patented Snap-Flat latch resolves these problems through intelligent design and use of appropriate materials.
The Snap-Flat Over Centre Latchprevents the accidental de-coupling of the latch and the catch plate due to the spring tension between them. The latch also reduces the likely hood of the latch not being disconnected properly as it visibly and audibly disconnects. That is, because one can see and hear the Latch disconnect from the catch plate, it is difficult to make the mistake of leaving a latch connected and thus damage the lifting mechanism.
The Snap-Flat latch’s design and use of 304 stainless steel ensures strength and long-term durability. For full details including the Snap-Flat Caravan style latch’s measurements and installation instructions, download the brochure below;
The image below shows the Caravan version of the Snap-Flat latch, which can easily be retrofitted to most pop top caravans and hybrid caravans.
The European Patent Office has granted a patent for Uniseg’s Snap-Flat latch for France, Germany & the UK. The certificate was issued for European Patent No. 3215430 in the name of UNISEG Products Pty Ltd entitled “LATCH MECHANISM”.
Patents have been previously granted for the Snap-Flat latch in Australia and South Africa and applications in progress for USA, Canada, China, India, Malaysia and Japan.
The Australian Patent Office has issued on 17th October 2019, a Certificate of Grant for Uniseg Products’ Snap-Flat latch. The certificate was issued for Australian Patent No. 2015342730 in the name of UNISEG Products Pty Ltd entitled A CONTAINER (Currently being renamed A LATCH MECHANISM).
In further positive developments the European Patent Office has allowed our patent application for the latch. The allowance of the application completes the examination phase of the procedure for obtaining a European patent. The grant procedure has now been filed for a European patent to be issued on this application with validation of the patent in the European member countries to follow shortly.
Uniseg Products have patent applications for the latch in progress in USA, Canada, China, India, Malaysia, Japan & South Africa.
The main improvements for version 4.2 of the latch, include;
Increased pin dimension by 50% from 4 to 6mm, to considerably strengthen the latch.
Adjust inner & outer spring tensions to achieve a better balance the tensions between the handle and the latch.
Added extra lockable eyelet (from 1 to 2)
A yield and destruction test of the latch confirmed that the latch deformed at 13.4 kN or 1.365 Tonne. Uniseg would expect the latch to easily handle forces up to 1 Tonne, which would make it one of the strongest over-centre latches, of this size, available.
A copy of the yield & destruction test report, carried our by Proofload, can be found below;