Commonly known as a type of mechanical fastener, toggle latches join two or more objects and allow regular separation. They typically engage another piece of hardware on another mounting surface. Depending on their design and type, the hardware may be known as a strike or catch. As a rule of thumb, the ultimate tensile strength (UTS) or load rating of your latch should be twice the maximum load expected. Well made over centre latches will state the UTS or load rating in their specifications. The Snap-Flat Caravan Latch design delivers 2 important safety benefits compared to conventional over centre latches / fasteners.

The first is the ‘FAIL-SAFE’ feature, where due to the tension created by one of the springs, the centre latch arm is prevented from accidentally de-coupling from the catch plate or hook. The Snap-Flat TM centre latch will stay secured to the hook even when no longer in the over centre position. This safety feature is particularly important in “moving” applications – see “ When Do I need a Snap-Flat Latch“.Dunn and Watson has been providing high quality hardware, accessories and spare parts across Australia for decades. Firstly the Snap-Flat latch’s spring tension prevents the latch from disengaging from the hook, even if the latch has not been NOT secured into the over-centre position. This prevents a potentially deadly accident if the pop-top’s roof lifts-up and blows away during towing. The Snap-Flat TM Latch is a conventional adjustable Over Centre Latch (also often referred to as a toggle latch) with a critical difference. It has been fitted with 2 springs that deliver 2 compelling benefits. Heavy duty fasteners don’t need to be heavy. Our Over Centre Fastener is designed and fabricated to ensure a lighter weight solution. Manufactured with an internal spring that can keep pace with frequent, long term use, and a bolt on body and weld on catch plate, this lightweight solution is ready for immediate installation and use. Latching Several problems have been identified with the use of over centre latches or centre fasteners on pop top caravans (sometimes referred to pop top roof clamps or pop top roof clips). The most critical is the tendency for existing adjustable over centre latches to accidently decouple while driving, potentially resulting in the pop top’s roof blowing off. While this is obviously an expensive accident the real concern is the potential to cause an accident with nearby motorist. For full details on the problems with traditional pop top caravan latches and how the Snap-Flat TM latches resolves these. The use of stainless steel enhances the durability and life span of the Snap-Flat latch, which can be important in Australia’s harsh environment.

Medium duty: Designed for applications with a maximum load between 125 to 750kg. The extra strength can ensure they do not accidentally open or fail due to vibrations. Common applications include transport boxes or cases, toolboxes and industrial cabinets. For ‘moving’ applications, if the latch accidently dis-engaging is of a concern, a ‘self-closing’ latch such as the Snap-Flat latch should be considered. Over Centre Latches are commonly available in mild steel, zinc coated steel and stainless steel (304 and 316). The material used will affect the latches strength and durability. For corrosive environments stainless steel over centre latches should be considered. Light duty: Designed for applications where there is little force or load, typically less than 125kg. They are mainly used for stationary objects like cabinets and boxes that are not subject to vibration or regular movement. They are typically small, easy to use and very affordable. The next most important requirement is ensuring that the over centre latch has sufficient strength for your application. Again, for stationary application this is usually not particularly important however for moving applications where safety is often critical, you do not want your latch breaking.The type of latch you choose may be dictated by the available space or ‘real estate’ you have for installing the latch and its catch plate. For example, some boxes or toolboxes have limited space and hence only a small sized latch can be used. Make sure you have measured the space available and that this will be adequate to accommodate you latch in it shortest and longest configurations. Similarly, the catch plates (hooks) must be of an equivalent strength to the latch as also the method of securing or fastening the latch and catch plates. No point having a strong latch for the catch plate or fasteners to fail.