Rod device for use as an arm of an excavator

An excavator comprising:

• a base structure;
• a boom pivotally attached to said base structure at a first end and having a second end;
• an excavator head;
• an excavator head supporting arm including;
• a plurality of telescopic tubular elements including an outermost element, at least one intermediate element and an innermost element, the outermost element being pivotally mounted to said second end of said boom at substantially an intermediate portion thereof, said excavator head being mounted to said innermost element;
• movement restricting means for limiting the relative axial movement between adjacent ones of said telescoping elements;
• and
• cable telescopic control means connected between said outermost element and innermost element of said plurality of tubular elements for controlling the axial extension of said excavator head supporting arm;
• and
• fluid pressure operated linear actuator means having relatively movable opposite ends for pivotally tilting said excavator head supporting arm with respect to said boom, one of said opposite ends being pivotally connected to substantially a middle portion of said boom while the other of said opposite ends is pivotally connected to a portion of said outermost tubular element substantially distant from the pivot point between said outermost tubular element and said second end of said boom towards the one end thereof being opposite to the other end thereof for supporting said excavator head;
• wherein said relative axial movement restricting means includes first and second pulleys mounted on said at least one intermediate element of said tubular elements adjacent its opposite ends, and first and second cables engaged around said two pulleys, said cables each being connected at their opposite ends with an end portion of adjacent tubular elements which engage with opposite ends of said at least one intermediate element.