History of screwdriver

The cross screw and cross screwdriver were invented by Henry Phillips in the 1930s. First, it is used on the assembly line of automobiles. Therefore, Phillips screw and Phillips screwdriver are also called Philips screw and Philips screwdriver.
In order to impose a small torque on the slotted screw, people thought of opening a slot on the screw head, and using the corresponding slotted screwdriver can easily tighten and loosen the screw. However, with the rapid development of science and technology, the application of the screw is becoming more and more widespread, and the shortcomings of the screw and slotted screwdriver also appear. First, once the slot of the screw head is damaged, the screw cannot be screwed out. The longer the slot length is, the easier it is to be damaged in the process of being twisted.
In order to shorten the length of the notch, improve the ability of the notch to resist damage, and transmit the same amount of torque, people think of using a cross groove, which can withstand the same torque, but the length of a notch is half shorter, and the resistance to damage is greatly enhanced. The screwdriver is originally a zigzag type and cannot be used for cross-recessed screws. Only another cross-recessed screwdriver corresponding to cross-recessed screws is produced. There are two kinds of screwdrivers.
The slotted screw has been used since the machine was invented. It is impossible to replace all the screws on the old machine. The cross screwdriver cannot be used on the slotted slot. The slotted screw is still used in production, so the slotted screwdriver should be retained. In this way, most of the new machines use cross-recess screws, and the old ones are still in use, so it is possible to use two screwdrivers at the same time.