我厂1985年以前生产的TC1型凸轮测量头的读数机构因没有“调零”,给使用者带来很大不便。为此,我们对TC1型凸轮测量头进行了改造,研制出读数“调零”的TC1A型凸轮测量头,其具体结构原理如图所示。当转动“调零”手轮1时,可动物镜筒座5连同40×投影物镜筒2沿导轨6相对于毫米刻尺4纵向移动1mm,则在影屏分划板3上的像移动40mm,实现了1mm的读数调零。这种“调 TC1-type cam measuring head produced before 1985 in our factory has no inconvenience to the users due to lack of “zero adjustment”. For this reason, we have reformed the TC1 type cam measuring head and developed the TC1A type cam measuring head which reads “zeroing”. The concrete structure principle is as shown in the figure. When the “zero” hand wheel 1 is rotated, the movable lens barrel base 5 along with the 40 × projection object lens barrel 2 is moved longitudinally by 1 mm relative to the millimeter scale 4 along the guide rail 6, the image on the reticle reticle 3 is moved by 40 mm , To achieve a 1mm reading zero. This "tune