普通千斤顶一般是由一个底座和一个顶尖所组成,在划线时,时常是因工件的形状不同来进行大幅度的调整找正,但有时遇到有些零件,将顶尖调到最高点或最低点还是满足不了要求,只好再将零件放下来,找些铁块垫在底座的下面来进行找正,加垫的顶尖给另外两个顶尖造成了失稳现象,容易发生危险。为此我们进行了改进,如图所示,该千斤顶可作两次调高,在正常使用时,只调整顶尖1就可以了,遇到凸凹零件需大幅度调 Ordinary jack is generally composed of a base and a top, in the marking, often due to the shape of the workpiece to a substantial adjustment to find positive, but sometimes encountered some parts, the top to the highest point or the lowest point Still can not meet the requirements, had to put the parts down, to find some iron pad under the base to be found, padded top to the other two top cause instability, prone to danger. To this end we have made improvements, as shown in the figure, the jack can be adjusted twice, in normal use, only adjust the top 1 on it, the convex and concave parts to be greatly adjusted