Control apparatus for the arm of a working machine in form of a kinematically similar reduced scale lever assembly

A control apparatus for controlling the working arm (15) of a machine (10), the arm (15) including a plurality of relatively pivotal arm members (16,20), a first (16) of the arm members, towards one end thereof, being pivotal, relative to a body (11) of the machine (10) about a first generally horizontal axis (A) by actuator means (18), and relative to the body (11) of the machine (10) about a generally upright axis (B) by actuator means (19a,19b), and towards the other end of the first arm member (16), the first arm member (16) being pivoted to the second arm member (20) towards one end of the second arm member (20) about a second generally horizontal axis (C) with actuator means (22) between the first and second arm members (16,20) to effect relative pivoting, the control apparatus including a base (31), a first control link (32) pivoted towards one end thereof to the base (31) at a first joint (33) which permits pivoting movement of the first link (32) about a first generally horizontal axis (A'), and the first link (32) being pivotal relative to the base (31) about a generally upright axis (B'), and pivoting movement towards a second end thereof to a second control link (36) at a second joint (37) for movement about a second generally horizontal axis (C') whereby the geometry of the control apparatus mimics the geometry of the working arm (15) to be controlled.