What is the principle of keyboard switch? Quality determines sales

The principle of keyboard switch:

There are six long strip welding joints, two double-pole double-throw, two middle welding joints are input and four outside welding joints are output. There are two independent single-pole double-throw switches, two groups of synchronous action. After pushing, the middle input end and the far end of the welding joint are turned on, and then pushing will bounce back. The middle input end and the near end of the welding joint are turned on.

The structure diagram of keyboard switch is mainly composed of keyboard assembly, skateboard mechanism and contact switch group.

Each key assembly includes keys, key rods, key reset springs, etc. The middle part of the key rod has a protruding cross beam, which is pressed on a trapezoidal insulating block, while one end of the key rod is pressed on the inclined surface of the slide-pull bump, and the lower part of the key rod is sleeved on the reset spring. When a block key is pressed, the key rod drives the trapezoidal insulating block down, and the insulating block drives the lateral contact switch reed to close it.

The skateboard mechanism is composed of a skateboard, a skateboard reset spring and a retaining lock block. There is a convex tenon at each key rod. It has a slope above and a groove below. The cross beam of the key rod is pressed on the inclined plane. When the key rod moves down, the cross beam compresses the inclined plane to make the slide plate move sideways. When the transverse beam falls into the groove of the convex tenon, under the action of the slide plate reset spring, the slide plate is reset, and the convex tenon locks the key rod to maintain the contact closure. At this time, if the second button is pressed, the sliding plate is pushed sideward by its cross beam, and the first button bounces back under the action of the button reset spring, and the electric contact is disconnected. The second key moves down to close the corresponding contacts, and the skateboard locks the key rod.

In order to avoid short circuit caused by pressing two keys at the same time, there is also a stop lock block on the keyboard switch. Its shape is trapezoidal, which is set in the horizontal groove of the slide board and is located between the two adjacent keybars. When two keys are pressed at the same time, because the width of the retaining lock block is slightly larger than the distance between the centers of the two keys, the cross beams of the two keys are blocked at the same time and can not be moved down.

The position of the contact switch group is on the inner side of the plastic housing of the keyboard switch. Each contact switch consists of a moving contact and a static contact. Three static contacts are connected together, and three dynamic contacts are riveted on three strip reeds respectively. When the key rod moves down, the trapezoidal plastic insulating pin under the cross beam of the key rod drives the moving contact spring to close with the static contact. When the key rod bounces, the dynamic and static contacts are separated and the switch is disconnected due to the elasticity of the spring.