Quick couplers (also called quick hitches) are used with construction machines to allow the rapid change of buckets and attachments on the machine. They remove the need to use hammers to manually drive out and insert the mounting pins for attachments. They also bring with them additional safety risks that must be overcome by careful design and manufacture, and proper use. Description Quick couplers are devices installed at the outer end of the work equipment of various types of construction and earth-moving machines. They facilitate the rapid exchange of working tools or buckets. Quick couplers are most common on hydraulic excavators and compact excavators and on the backhoe equipment of backhoe loaders, but are also installed on telescopic handlers, wheel loaders (loading shovels), skid-steer loaders and the loader equipment of backhoe-loaders. They are also occasionally installed on attachments installed on agricultural tractors. 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. They are usually mounted on the machine by means of the pins that would otherwise be the mountings for the bucket or attachment. This article concentrates on quick couplers installed on excavators and similar equipment. Types There are many variations in the design of quick couplers. The initial divergence is between those that can pick up any of a range of buckets and attachments by clamping onto the mounting pins for the attachment (known as "pin grabbers" or "pin couplers") and those that work only with buckets and attachments designed to suit that quick coupler (known as "dedicated"). 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. Source: En. Wikipedia. Org
Source:
http://en.wikipedia.org/wiki/Quick_coupler