PROBLEM TO BE SOLVED: To solve the problem that in extending/contracting boots for covering the outer circumference of a lead cam shaft for reciprocatively moving a seedling tank of a seedling planting machine in a right and left direction, suction and discharge of muddy water are likely to occur by suction and exhaust action of air in boot chambers, the muddy water to be sucked and discharged is mixed with a lubricating oil or the like in the boot chambers and the lubricating oil is discharged to the surface of a paddy field, which is often contaminated.SOLUTION: The outer circumferential part of the lead cam shaft 3 that is fitted with a lead cam 2 integrally attached to the seedling tank 1 and reciprocatively moved along the direction of seedling tank width is equipped with the lead cam 2 fitted with and guided by the lead cam shaft 3 and a pair of right and left extending/contracting boots 4 and 5 for covering both end parts of the lead cam shaft 3 between both end parts, respectively, and the boot chambers 6 and 7 in the pair of the right and left extending/contracting boots 4 and 5 freely communicate with each other so as to perform free ventilation.COPYRIGHT: (C)2011,JPO&INPIT【課題】 苗植機の苗タンクを左右方向へ往復移動するためのリードカム軸の外周を覆う拡縮ブーツにあっては、ブーツ室内への吸気、排気作用によって、泥水の吸入、排出が起り易く、この吸排する泥水にはブーツ室内の潤滑油等をも混入させて、田面に潤滑油を排出させて汚すことが多い。【解決手段】 苗タンク1と一体的に設けるリードカム2を嵌合して苗タンク幅の方向へ沿って往復移動するリードカム軸3の外周部に、このリードカム軸3に嵌合案内されるリードカム2と、このリードカム軸3の両端部との間にわたって各々覆う左右一対の拡縮ブーツ4、5を設け、これら左右一対の拡縮ブーツ4、5内のブーツ室6、7相互間を通気自在に連通する。【選択図】 図1
