Locking mechanisms include double locking, dual locking, and multi locking. Locking quick hitches are known by a variety of different names, but they all serve the same general purpose.
In layman's terms, double locking means that the hydraulically operated Quick Coupler is equipped with mechanical locking devices that hold both pins of an attachment in place while the tilting quick coupler is being operated.
What is it supposed to achieve?
Simply put, it should make it easier to pick up attachments and then reliably hold them in place while operating, even in the event of an unexpected incident.
In addition, compliance should be required for any type of hitch, including those that are double locking.
The majority of Quick Hitches available on the market today, particularly in New Zealand and Australia, use a 'Force Locked' style of locking attachments into the coupler, which is a more secure method of locking attachments into the coupler.
A force-locked engagement system, as defined by the ISO standard 13031:2016, is one that requires continuous application of force to maintain the attachment's position, as it would be released if the working force were to stop.
Following that, the ISO standard specifies what these couplers must accomplish in order to be considered compliant. To accomplish this, the attachment must be automatically locked in place upon engagement, provide visual cues that the operator can easily recognize as signs of securement, and maintain its operating position even if the hydraulic power is completely cut off from the system.
Furthermore, they must prevent the attachment from swinging in the event of a loss of engagement force. Moving the front pin is dangerous and completely non-compliant with OSHA regulations.