By Tobias Huber

Quarter-turn fasteners (affectionately known as quarter-turns) were first invented in the 1930's as an easy opening alternative to nuts and bolts, while still providing a secure fastening solution in applications where access is required on a regular basis. The Camloc brand was established in 1937.

                 

 

With more than 80 years of experience in the design and manufacture of quick-release quarter-turn fasteners, Camloc have established a reputation within the industry as a well-respected and trusted name. Additional to the original production facility in the USA, there is also a production facility in Kelkheim, Germany today. Camloc fasteners are developed and manufactured at this location.

What is a quarter-turn fastener?

A quarter-turn fastener is a mechanically locking quick-release fastener that consists of a stud, retainer and receptacle.

Quarter-turn fasteners provide a secure, vibration-resistant, quick release fastener system which can be easily opened by hand or tool.

What are quarter-turn fasteners used for?

Quarter-turn fasteners are typically used where there is a need for quick and frequent access. They are most used in applications where there is a need for regular opening and closing of the panel, such as in panelling for access to areas containing equipment that may require regular inspection or maintenance.

There are many benefits to using quarter-turn fasteners, with significant time (and therefore financial cost saving) being a key consideration in many circumstances.

How do quarter-turn fasteners work?

Quarter-turn fasteners can be operated by hand or by a tool (depending on the head style of the stud). When the stud is turned 90°, the stud assembly is rotated and the cross pin rides up the cam causing a controlled joint preload to be applied. A positive mechanical stop is reached and the cross-pin falls into the locking position. The reverse turn motion will unlock the system, allowing quick and easy access.

Quarter-turn fasteners connect components under an elastic preload. The spring element to produce the preload can be part of the stud or receptacle. Fastener tensile loads specified in the catalogue are reached after overcoming the spring element generated preload.

Unlike threaded fasteners, Camloc fasteners do not rely on the elasticity of joint and fastener materials to accomplish preload. The stud assembly or receptacle is designed with a spring element which allows repeated application of controlled preload with assured reliability over cycles.

 

What head styles are available?

There are a variety of head style shapes available such as slotted recess, head cross, recess head, hex head, hex recess head and many more. It is important to note that not every series offers the same head styles. Special, bespoke solutions can also be offered for certain applications (dependent on volume).

In applications where the closure must be tamper proof, there are head styles available which must be operated by a specialist tool.

 

Hand Operated Head Style Examples Tool Operated Head Style Examples

 

What are typical applications for quarter-turn fasteners?

Quarter-turn fasteners can be found in a variety of applications. They are very versatile, making them suitable for use in a variety of industries; including aerospace, rail, truck & trailer, agriculture, and motorsport.

In the rail industry, the maintenance panels on top of and below the train are good examples of where quarter-turn fasteners are frequently used. The number of quick access maintenance panels in a train would make it a very time consuming process to open and close multiple panels that are fastened with screws.

In trucks, there are various applications where quarter-turn latches are used. This can positively reduce maintenance time due to the advantage of quick opening and closing.

 

Captive quarter-turn fasteners are retained within the application once locked or unlocked. They are suitable for applications where the loss of the fastener would be extremely critical – such as in aircraft; or, where loss of the fastener would be more likely such as agriculture or motorsport.

The excellent vibration resistance of Camloc quarter-turn fasteners ensures they are ideal for use in machines, trucks, agriculture and trains.


HFS Industrial can offer special, bespoke solutions for challenging applications. If you'd like to discuss your application with us, please send an email to [email protected]