| 摘要 |
<P>PROBLEM TO BE SOLVED: To hold an upper frame capable of oscillating along the motion trajectory of a quadric crank chain that takes an inclined posture and an approximately horizontal posture in the approximately horizontal posture by a simple operation when necessary. <P>SOLUTION: An upper frame 20 capable of oscillating along the motion trajectory of a quadric crank chain between an inclined posture and an approximately horizontal posture is forcibly displaced to the approximately horizontal posture and held. A front link mechanism control means 100 applies external force for pushing down an operation member 120 to thereby control a front link mechanism 30 such that the front side of the upper frame 20 is displaced backward while being lowered. The direction of the displacement for bringing the upper frame 20 into the approximately horizontal posture and the direction of an operation for locking the front link mechanism 30 or a back link mechanism 40 by the operation of the operation member become approximately the same direction as each other, and consequently two movements, a displacement movement to the approximately horizontal posture and a lock movement, can be performed only by operating the operation member in a predetermined direction. <P>COPYRIGHT: (C)2013,JPO&INPIT |
