Actuating mechanism for a ground-engaging tool

An actuating mechanism for controlling the movement of a tool which is adapted to selectively engage the ground while being translated therealong, comprising:

• a frame adapted to be translated along the ground at a ground speed;
• a cam mounted on said frame for rotational movement about a first axis, said cam having a cam surface configured as a surface of revolution generated about a second axis positioned eccentrically with respect to said first axis;
• a link having a first marginal end portion mounted on said frame for rotational movement about a third axis and having a second marginal end portion;
• a member mounted on said link second marginal end portion for rotational movement about a fourth axis, said member having a follower arranged to engage said cam surface, said cam and link means being so oriented and arranged with respect to one another that a line between said first and second axes will be substantially equal in length and parallel to a line between said third and fourth axes so as to maintain the spatial orientation of said member as said cam and link rotate about their respective rotational axes with said frame, said member having a horizontal velocity component which is sinusoidal and having a vertical velocity component which is also sinusoidal but which is substantially 90 degrees out-of-phase with respect to said horizontal component, said member also carrying a tool;
• and
• motor means for rotating at least one of said cam and link means about its rotational axis with said frame in an angular direction and at an angular speed such that, when said member is in the vicinity of its bottom dead center position, the horizontal velocity component of said member will be of such magnitude and direction as to substantially cancel the ground speed of said frame;
• whereby said tool may be selectively lowered to engage the ground at a substantially-zero net horizontal speed relative thereto.