公开(公告)号：US5765980A

公开(公告)日：1998-06-16

申请号：US822638

申请日：1997-03-21

申请人： Katsunori Sudo ,  Yukichi Iwata

发明人： Katsunori Sudo ,  Yukichi Iwata

IPC分类号： F16B23/00 ,  F16B35/06

CPC分类号： F16B23/0023 ,  F16B23/0076 ,  Y10S411/911 ,  Y10S411/919

摘要： A cross-recessed head screw has in its head a tool engagement recess including first releasing surfaces which are adapted to be engaged with generally flat front edges of an end of a cross-headed tip screwdriver and have the function of moving the screwdriver backward when the screwdriver is turned in the reverse direction for loosening the screw. The tool engagement recess further has second releasing surfaces each contiguous to a corresponding one of the first releasing surfaces and serve to guide the backward movement of the screwdriver as the latter is turned in the screw-loosening reverse direction. By virtue of engagement between the first releasing surfaces and the front edges of the screwdriver, the reverse rotation of the screwdriver produces only a small friction torque which is quite insufficient to cause rotation of the screw in the screw-loosening direction. The first releasing surfaces project from the second releasing surfaces toward the axis of the tool engagement recess, so that when a screwdriver one size smaller than the specified screwdriver is inserted into the tool engagement recess, a tip end of the one-size-smaller screwdriver comes into abutment with only a small area extending in the vicinity of inner edges of the respective first releasing surface. With this small contact area provided between the tool tip and the first releasing surfaces, the screwdriver is likely to slip or turn freely when it is rotated in the reverse direction.

摘要翻译： 十字凹头螺钉在其头部具有工具接合凹槽，其包括第一释放表面，其适于与十字头尖端螺丝刀的端部的大致平坦的前边缘接合，并且具有当螺丝刀向后移动时的功能 螺丝刀向相反方向旋转，松动螺丝。 工具接合凹槽还具有第二释放表面，每个第二释放表面与第一释放表面中的对应的一个相邻，并且用于引导螺丝刀在螺钉松动反向方向上转动时的向后移动。 由于螺丝刀的第一释放表面和前边缘之间的接合，螺丝刀的反向旋转产生的摩擦转矩小，这在螺丝松动方向上不足以使螺杆旋转。 第一释放表面从第二释放表面朝向工具接合凹槽的轴线突出，使得当将一个尺寸小于指定的螺丝刀的螺丝刀插入到工具接合凹部中时，一个小尺寸的螺丝刀的尖端 仅与在相应的第一释放表面的内边缘附近延伸的小区域抵接。 通过在工具尖端和第一释放表面之间设置的这个小的接触区域，当螺丝刀沿相反方向旋转时，螺丝刀可能会自由滑动或转动。