| 摘要 |
<P>PROBLEM TO BE SOLVED: To secure safety even when an obstacle exists in the movable range of a structural member. <P>SOLUTION: A prize field 16L is supported from a lower part by a plurality of X members for changing the height of the prize field 16L. A field motor 45 supplies drive force to vertically move the prize field 16L via the X members. A slider block 60a and a nut 61a stored inside a slide unit transmit the drive force from the field motor 45 to the X members when the prize field 16L can be lowered by the X members, and are separated not to transmit the drive force from the field motor 45 when the prize field can not be lowered by the X members due to an obstacle, etc. <P>COPYRIGHT: (C)2013,JPO&INPIT |
