Gang mower with cutting units having suspensions incorporating tuned mass dampers

A mower for cutting grass, which comprises:

• (a) a frame supported for movement over the ground by a plurality of wheels, wherein at least one of the wheels is powered by a prime mover carried on the frame for causing the frame to be self-propelled, the frame having a support for carrying an operator thereon during a grass mowing operation;
• (b) a plurality of grass cutting units carried on the frame in a gang configuration such that the cutting units collectively cut a swath of grass that is wider than a swath of grass cut by any one cutting unit;
• (c) a plurality of suspensions extending between the frame and the cutting units for connecting the cutting units to the frame such that the cutting units are propelled over the ground by the self-propulsion of the frame over the ground, wherein one suspension is provided for each cutting unit, and wherein each suspension comprises:
• (i) a pivotal lift and lower suspension portion attached to the frame for raising the cutting unit above the ground to place the cutting unit into a transport position in which the frame may be driven from place to place without cutting grass and for lowering the cutting unit into contact with the ground to permit the cutting unit to cut grass in the grass mowing operation;
• and
• (ii) a ground contour following suspension portion connecting the lift and lower suspension portion to the cutting unit to permit the cutting unit to move relative to the lift and lower suspension portion to adapt to ground contours independently of the frame, wherein the ground contour following suspension portion includes a steering head that is directly attached to the lift and lower suspension portion to permit the steering head and the cutting unit to pivot about a substantially vertical yaw axis relative to the lift and lower suspension portion;
• and
• (d) a mass damper attached to and movably carried by the steering head of the ground contour following suspension portion of each suspension for vertical upward and downward motion relative to each suspension which mass damper motion is counter to and damps an upward and downward harmonic bobbing motion of the cutting unit experienced by the cutting unit during the grass mowing operation.

A mower, which comprises:

• (a) a plurality of grass cutting units arranged in a gang configuration on a movable frame, wherein the grass cutting units are reel cutting units or rotary cutting decks;
• (b) a separate suspension carrying each grass cutting unit and separately connecting each grass cutting unit to the frame, wherein each suspension includes a lift and lower portion for lifting and lowering the cutting unit out of and into contact with the ground, respectively, and a ground contour following portion to permit the cutting unit to independently follow the ground contours the cutting unit encounters in a grass cutting mode of operation, wherein the ground contour following suspension portion includes a pair of laterally spaced pitch arms having hubs that are pivotally journalled by laterally spaced cylindrical members on the grass cutting unit to permit the cutting unit to pivot or rock about a substantially horizontal, laterally extending pitch axis, and wherein a radial clearance between the hub of each pitch arm and the cylindrical member which journals each pitch arm is approximately ten thousandths of an inch or less;
• and
• (c) at least one tuned mass damper installed in each suspension for damping undesired vertical bobbing of the cutting unit.