Quick couplers are devices installed at the outer end of the work equipment of various types of construction and earth-moving machines.
Quick couplers do not normally have a specific function themselves in that they do not carry out handling or digging operations, but when installed on a machine they become a part of the overall system.
The claimed advantage of pin-grabbers is flexibility in use in that a machine owner can use a variety of buckets and attachments without changing the quick coupler or buying an adaptor.
The claimed advantages of dedicated couplers depend on their individual design but often include better performance and smaller size.
In Australia the authorities took the view that the problems were caused by designs of quick couplers that did not incorporate a safety pin.
In the UK some major construction contractors have written their own specifications for quick couplers allowed on sites under their control.
Many of the manufacturers of quick couplers are small, flexible and innovative, leading to the wide variation in design concepts.
In addition to the supply route from the OEMs many distributors of construction machinery will install quick couplers onto machines before delivery at the request of a customer.
Quick coupler manufacturers will also sell direct to end-users and usually complete the installation as part of the sale.
Because of this the UK government launched a "safeguard action" under the Machinery Safety Directive (98/37/EC) challenging the validity of the standard and demanding that it be improved.