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A three point backhoe is an excavation attachment that can be installed on a tractor unit and operated directly from the driver’s position. The term is also used to describe the backhoe arm as fitted to wheeled excavators, such as the 3CX model produced by Joseph Cyril Bamford Equipment Ltd (JCB) in the United Kingdom (UK). The main difference between a three point backhoe and a standard backhoe is the additional hinge point positioned directly on the point at which the boom arm connects to the machine. This third hinge allows the backhoe arm to be hydraulically folded and locked in place directly behind the driver, allowing the tractor or wheeled excavator to be used in a traditional manner.
The operation method required for a three point backhoe differs from the Society of Automotive Engineers International (SAE) and the International Organization for Standardization (ISO) control systems commonly found in traditional backhoes. Under the SAE and ISO control systems, the backhoe is fully operated with two levers, one for each hand of the operator. Each control lever operates two functions, one in the forward-to-backward direction and another in the left-to-right direction.
When operating a three point backhoe attachment, the movements are controlled by three levers that only operate in a forward-to-backward direction. The levers, in order from the left-hand to the right-hand side of the operator, control the vertical bucket rotation, vertical dipper arm movement, and vertical boom arm movement. Additional levers, generally located on either side of the main control panel, raise and lower the left and right stabilizer legs, respectively. In addition, there are two pedals that control the horizontal swing of the boom arm, with the left pedal controlling the left swing and the right pedal moving the boom arm in the opposite direction.
By raising the boom arm and the pulling the dipper arm to the point closest to the operator, the backhoe can be placed in a locked position for traveling. This is achieved by engaging a boom lock latch lever from the operating position. While this safety feature allows the tractor to be moved with the attachment still fixed to the machine, it is not particularly safe for road travel. Three point backhoe attachments for tractors are removable for this reason as well as to provide the option of changing attachments.
On a wheeled excavator where the three point backhoe is permanently fixed, the boom arm can also be moved along a track mounted on the back of the machine. This track not only allows the backhoe to be used when excavating an offset trench but also the backhoe arm to be stored more securely. For example, by moving the backhoe to the far right position of the machine, the boom arm can be swung fully to the left and locked in place, fixing the backhoe in a parallel position to the rear of the machine.
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