| 摘要 |
<p>PROBLEM TO BE SOLVED: To save the energy by forming a center of gravity moving mechanism into a link mechanism for connecting an upper end side of a second arm, which is upper than the center of turning thereof, and a weight so as to always balance the center of gravity of the arm and the center of gravity of a counter weight. SOLUTION: An upper end of a counter weight 12 and an upper end of an arm 3 are connected by a link mechanism 11 formed of the three-divided structure. The counter weight 12 is turned around a horizontal shaft 12a so that the upper end thereof is moved backward. With the turning of the counter weight 12, position of a center of gravity is moved backward from a position W1 to a position W2 . A moment in the direction for lowering a bucket 6 is generated in a boom 2 by a load to be applied to the center of gravity of the arm and a moment in the direction for lifting the bucket 6 in the boom 2 is generated by a dead weight of the counter weight 12. Consequently, balance is taken between both these moment, and a load to be applied to a boom cylinder 4 can be reduced.</p> |
