is provided below the clamping tube fixing block 22 the limiting shaft 21 is fixed on the sliding bush bracket 20 the working process of the present invention is as follows fig6 is the star state of the present invention the sliding rod base 4 and the sliding block 9 are disposed at the left side of the base 1 the strap drive 11 connected to the guide rod 5 is in a heeling condition and the distance between the sliding rod base cover 10 and the sliding block 9 is short and the sliding block 9 does not press on the flexible tube fig6 b is a schematic view showing the rotation motor 2 drives the sliding base 4 and the sliding block 9 to move right to squeeze the flexible tube the first motor 14 of the moving device for moving the sliding block up and down is started to rotate the strap drive 11 by the cooperation of the driven gear 12 and the driving gear 13 so that the strap drive 11 is in a vertical position therefore the sliding block 9 moves upward the distance between the sliding rod base cover 10 and the sliding block 9 becomes longer it can be seen from the different exposed lengths of the sliding rod base shafts 17 in fig6 a and fig6 b the rotation of the guide screw is driven by rotation motor 2 the.