在钻通孔时,自动减小钻头的进给量是预防钻头损坏的有效方法。本文所介绍的装置如图1所示。 在钻床主轴1上用锥柄装上壳体2,壳体2为空心的,在壳体圆柱壁上打了多个通孔,孔内放入钢球4,钢球外面与垫圈3的内锥面相接触,而钢球内面与心轴5的锥体相接触。在心轴5下端安装钻头卡子6, When drilling a through hole, automatically reducing the feed of the drill bit is an effective way to prevent the drill bit from being damaged. This article describes the device shown in Figure 1. In the drill spindle 1 taper shank mounted on the housing 2, the housing 2 is hollow, in the housing cylindrical wall hit a plurality of through holes, the hole into the ball 4, outside the ball and washer 3 Conical surface contact, and the inner surface of the steel ball cone 5 spindle contact. The lower end of the mandrel 5 to install a drill chuck 6,