JCB Backhoe Excavator
MW ModelPlan 222
This small backhoe excavator is built to scale to look as much like the real thing as possible. It is a device that needs elegant control, perhaps even with joysticks, just like the seated driver in his cab. In this way one can copy his actions exactly. There are many makes of hydraulic backhoe excavator on the market and all look similar.
This machine hugely amplifies the action of the human hand, and is not a robot but a machine known as a telecheric. It is controlled by bio-feedback – hand eye coordination. To see one in action is to appreciate just what these machines can do. It can load a lorry with soil moving tons in an hour and do it all day. Having rested at night after refueling, it returns again and again to the same job, reliable and efficient, working in the roughest environments. These machines have also been observed working as cranes, flattening surfaces, lifting liquids and concrete. They are pure beauty in motion for they are elegant in design and suit their function exactly. They differ one from the other only in size and power.
Hydraulics has been refined to be powerful and reliable, and challenges the Meccano builder, because he has nothing like it available in his stock of parts in the system. Many methods have been devised to simulate hydraulic action, from motor driven screwed rods to wire and trolley activation and linear rack and pinion activators and servos. It used to be thought that small scale hydraulics was not feasible, but it has been proved that this is not so. Indeed if a fluid-tight cylinder and piston can be moved mechanically by a motor, this motion can be transferred by tubing to another similar piston and cylinder. Even real hydraulics with hydraulic fluid in a closed pump system with electrically controlled valves has been produced.
The method chosen here is wire activated pistons, the action of which is hidden within the machines framework. A good appearance can be obtained with the strips and triangular flexible plates, but there are places where painting will be necessary. Black has been chosen for the track frames as in the prototype.
Some bending of parts is required and these can be restored to original after use. The track sprocket bosses are drilled to enable a screw to enter a coupling, but this does not prevent their use with their original plastic locking nuts.
Michael Adler 2016