There are many types of pliers, and they have a wide range of uses, and are an indispensable hand tool for pinching and shearing workpieces in various industries such as assembly, repair and installation. But it has a common basic structure, that is, any hand pliers county is composed of three parts: pliers, pin and handle. The basic principle of pliers is to use two levers, at a point in the middle, with pins to cross them together, so that the two ends can move relative to each other, as long as the tail end is operated by hand, the other end can pinch the object. In order to reduce the force used by the user during operation, according to the principle of mechanical lever, the handle of the pliers is usually longer than the pliers, so that a stronger clamping force can be obtained with less force to meet the requirements of use.
The three parts of the pliers are as follows:
A pair of handles for gripping. The ergonomically designed handle makes it easier to hold more securely and comfortably. Connecting shaft, which is the connection point of the pliers. The attachment points must move smoothly without any loosening, making it easy to open or close the pliers with one hand. The pliers head is equipped with a clamping mouth or cutting edge. The pliers are finely ground to the right shape. The two shear edges (with springs) must be very sharp and precisely closed to each other to easily cut the wire.
This converts a smaller external force (such as hand force applied to the forceps arm) into a larger force, allowing the pliers to grip or shear effectively. When the external force applied to the clamp arm increases with the leverage, the force on the clamp nozzle creates an external force that moves the clamp. If a large external force is to be generated, the distance from the center of the pliers riveting position to the handle must be as long as possible, and the distance from the clamping or shear to the riveting center must be as short as possible. However, many pliers do not greatly increase hand strength because they only make it easier to work in difficult places, such as the assembly of electronic equipment and electronic and precision engineering applications.
Pliers are usually forged from alloyed and unalloyed structural steel. For general pliers, they are made of high-quality carbon structural steel with a carbon content of 0.45%. High-quality and heavy-duty pliers are manufactured from high carbon content and/or alloying elements such as chromium or vanadium.
The origins of pliers in Europe date back to more than a thousand BC, when people first started casting iron. During the casting process, pliers can be used to hold hot iron blocks. The shape of the forged tongs of the past has been preserved to this day, and little has changed. The variety of pliers has expanded with the development of handicrafts, commerce and industrialization. The general clamp has developed to 100 types. The number of clamps for special applications is also increasing. Of course, these special pliers are not often available in the universal range. It is the only one in Germany with a monthly output of more than 1 million tongs, and about 50% of it is exported. The vast majority of them are general-purpose pliers, such as shear pliers, wire cutters and water pump pliers.
Regarding the features, the differences are as follows:
(1) Shear pliers, which can be used for cutting or trimming (side shears, front shears, pruners, etc.).
(2) Wire cutters, which can be used for shearing and clamping (wire cutters, crane nose pliers, electronic pliers, etc.).
Regarding the stranded structure, the differences are as follows:
(1) Butt twisting, such as woodworking pliers. They are mounted on top of the pliers and do not require milling and riveting.
(2) Single shear twisting, such as wire cutters. Milling the joints to mill half the thickness so that the two pieces of pliers are inserted into each other for installation.
(3) Casing type twisting, one handle has a groove through it, let the other handle pass through the groove, and twist at the joint. Casing twisted pliers - except for pump pliers - are more expensive to manufacture because they are more difficult to manufacture using harder alloy steel. Therefore, compared with the first two twisting methods, it is relatively secondary.