| 摘要 |
<p>In a toggle type punch driving system, the upper and lower ends of a bendable lever which can bend at an intermediate part thereof are pivotably connected to a fulcrum member and a ram respectively, and an advancing/retreating member for bending the lever is connected to the bendable part of the bending lever. The fulcrum member is formed as a vertically pivotable lever and it is borne by an upper/lower position switchover mechanism composed of a second bendable lever supported between a free end of the fulcrum member and frame, and an air cylinder. A retraction stroke of the ram necessary for tool change is assigned to the bending motion of the second bendable lever to diminish the punching stroke of the ram based on the bending motion of the bendable lever.</p> |
