The first two kinds of drill chuck were invented by foreigners, introduced to China and copied by China. For example, the Jacobs drill chuck in the United States was invented by an American, Mr. A.I. Jacobs, 100 years ago. The third kind of vice drill chuck (China Shaw drill chuck) was recently invented by "Shaw" in China, and won the national invention patent, with completely independent intellectual property rights.
The first two kinds of drill chuck are characterized by three claws and three faces acting on the drill shank. China Shaw drill chuck is characterized by two claws and four faces. That is to say, if a symmetrical diamond groove is opened on each jaw, there are four faces to hold the drill bit. Clamp the drill bit like a vise, so the performance is better than three-jaw clamping.
Easy to use comparison:
Loosen the tool wrench relative to the jigs used in the first two kinds of drill chuck. One is a crescent hook wrench and the other is a gear key wrench.
It has two main disadvantages:
The disadvantage (1) is single,
In other words, each drill chuck is equipped with a unique one-to-one wrench. When the wrench is damaged, lost or forgotten. It will affect the use of drill chuck, especially in the process of production and processing, because the wrench delays production, especially anxious to get angry.
Disadvantage (2) is not suitable for the principle of human mechanical engineering. When the crescent hook wrench is loosened, the force applied by it is the same as the rotation direction of the shaft, and it is necessary to give the shaft a reverse force to brake, so as to complete the operation of loosening and replacing the bit.
The gear key wrench, in order to complete the elastic drill chuck, must be held at the T-joint of the gear key wrench, and three components are applied at the joint to complete the operation. That is, the force that the center line of the tooth key of the first component coincides with the center line of the positioning shaft hole points to the depth of the positioning shaft hole to ensure that the half shaft of the tooth key is firmly embedded in the positioning hole of the drill chuck. The second component is the force perpendicular to the axis of the gear key, which is mainly used for the chuck of the elastic drill. The third component. That is, the gear key wrench, the fixed shaft is fixed with a single-hole half shaft. When the gear rotates, there must be a downward force on the side without the fixed shaft, which makes the gear have teeth. Therefore, it is necessary to artificially apply a force to keep the gear keys concentric. Upward force.
There is also a Shaw drill chuck: the elastic wrench method is better than theirs. Its elastic wrench is a universal hexagonal wrench with absolute interchangeability. The Allen key can be found in any place where the China Shaw drill chuck is needed, which is convenient for emergency use and avoids the specificity of the gear wrench and the inconvenience and trouble after being damaged or lost. In addition, there is a kind of Allen wrench, which is superior to gear wrench in performance. 1, the standard right-angle arm of the Allen wrench is very long, and the lever arm is very long when you hold it, which is very labor-saving (no hand sticking). Moreover, the two inner six holes are symmetrical, and two Allen wrenches can be used to tighten and tighten at the same time if necessary. It is impossible to realize a gear wrench,
For the three-jaw chuck, the phenomena of relative, loose clamping and bit slipping often occur. However, the two-claw and four-sided chuck of Shaw vice completely put an end to this bit slipping phenomenon.