Screw mechanical rotation direction and use

The so-called spiral usually refers to a cylinder or a circular hole with uneven spiral stripes on the surface of bolts, hardware nuts, etc., where this cylinder is called a screw, the circular hole is called a nut, and the spiral The pattern stripes are called threads. The analysis of the spiral rotation direction and performance use is as follows:

Analysis of spiral rotation direction:

The screw thread can rotate in two directions according to the direction of the helix. Most spiral threads follow the clockwise direction, looking from either end of the spiral toward the shaft, if the spiral is rotated in a clockwise direction, the right-handed spiral will move away from the viewer.

The right-hand screw obeys the right-hand rule: hold the shaft with the fingers of your right hand in the direction of rotation, and straighten your thumb, the thumb will point to the direction of the shaft's linear movement. On the contrary, the left-handed spiral obeys the counterclockwise direction, looking from either end of the spiral toward the shaft, if the spiral is rotated in a counterclockwise direction, the left-handed spiral will move away from the viewer. The left-handed spiral obeys the left-hand rule. Grasp the shaft with the fingers of your left hand in the direction of rotation, and straighten your thumb, the thumb will point to the direction of the shaft's linear movement. (Guide: Remove rusty fasteners cleverly)

For right-handed people, it is easier to use a screwdriver to tighten a right-handed screw than to tighten a left-handed screw, because this action uses the supinator muscles that exert more force instead of having a lesser force. Anterior muscles. Since most people are right-handed, the thread fastener standard stipulates that the thread is right-handed.

Left-hand thread is often used in the following cases:

a. The rotation of the rod shaft will cause the general right-handed nut to loosen due to the micro-motion induced precession, but not to tighten. For example, the screws that fasten the left pedal to a bicycle, fasten the saw blade to a circular saw, and fasten the grinding wheel to a desktop grinder are all left-handed spirals.

b. Some devices have threads at both ends, such as turnbuckles and movable pipe sections. These devices have a right-hand thread and a left-hand thread. The rotating device can tighten or loosen the threads at both ends at the same time.

c. In order to prevent Xiaoxiaomen from stealing light bulbs for home use, railway stations or subways and other public facilities will use left-handed light bulbs.

d. According to traditional customs, the lid of the coffin is fastened with left-handed screws.

According to the spiral performance, its use is:

1. Using the self-locking nature of the screw (will be explained in detail later), the screw fastener uses a screw to fasten several objects together. For example, wood screws, metal nails, bolts and nuts, etc.

2. The self-locking property is the key property of the spiral in many applications. For example, screw caps, vices, C-clamps, screw jacks, etc.

3. The screw can be used as a connecting rod group for power transmission in machinery. For example, worm gear, lead screw, ball screw and so on. Due to the low efficiency, the spiral link group is rarely used to transmit high power, and is more common in low power, intermittent usage, such as position actuators.

4. Rotate the spiral surface around the axis of rotation to move materials, such as Archimedes screw pumps, augers, and screw conveyors.

5. Using the precision calibration screw, the micrometer can accurately measure the length.

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