What are the categories of handheld power tools?

　　What are the categories of handheld power tools?

Handheld power tools are simple to operate, lightweight and efficient. They are not only a good helper in family life, but also a powerful assistant in factory labor.

But these seemingly harmless little things actually hurt people frequently! There have been several bloody lessons around us!

When employees were installing glass doors, they paused the installation work at the request of other colleagues and wore wire gloves to carry the color steel plates. After the transfer, the employee continued to install the glass door without taking off the wire gloves. During the operation, the hand drill wrapped the wire gloves around, causing winding injuries.

When an employee of a certain department was working on color steel plates for partition walls, he found that the drill bit was loose, so he re-strengthened the drill bit without cutting off the power and taking anti-fake measures. His right hand accidentally touched the trigger, and the electric drill started instantly, cutting the employee’s left hand holding the drill bit.

The causes of the two accidents are extremely typical, both stemming from people’s unsafe behavior. Different from accidents caused by inherently unsafe equipment, these two accidents can be completely avoided by raising safety awareness and implementing safety requirements!

Get to know handheld power tools

According to the type of electrical protection, it can be divided into Class I tools, Class II tools, and Class III tools.

Class I Tools

The rated voltage exceeds 50V. In addition to basic insulation, there is an additional safety measure that requires grounding and is a triangular plug. This type of tool has poor safety and has long been discontinued.

Class II tools

Rated voltage exceeds 50V. In addition to basic insulation, the additional safety precautions of double insulation or reinforced insulation are provided. The handheld part is non-metal and marked with the “Hui” symbol.

Class III tools

The rated voltage does not exceed 50V. Powered by an extra-low voltage power supply, no voltage higher than the safety extra-low voltage is generated inside the tool. The housings of these tools are all plastic.

Security requirements

1. For general operations, Class II and Class III tools should be selected. When using Class II tools, a leakage protector with a rated electric shock action current of no more than 15mA and a rated action time of less than 0.1s should be installed;

2. When using Class I tools, in addition to the above requirements, zero protection is also required. The operator should wear insulating gloves, wear insulating shoes or work on an insulating mat;

3. It is prohibited to use Class I tools when working in wet places or on metal structures.

4. Class III tools must be used in narrow places (boilers, trenches, pipes, etc.).

5. Use rubber-sheathed copper-core flexible cables for load lines of handheld power tools. Plastic flower wires are prohibited.

Common handheld power tools

Hand drill

1. Check whether the plug, switch, handle and drill bit clamp are intact before operation;

2. After the drill bit is installed in the drill clamp, the chuck must be tightened, and at least 1/3 of the drill bit length must be inserted into the drill bit clamp;

3. Generally do not wear gloves when using, tie the cuffs and trousers tightly, and do not let your hair be disheveled;

4. No part of the human body may come into contact with moving parts;

5. During the rotation process, no barbaric operations such as warping, pulling, excessive pressure, etc. are allowed;

6. When removing, replacing or adjusting the drill bit, the voltage must be cut off (or the battery must be removed).

Angle Grinder

1. Before use, check that all parts are running well, that the grinding wheel has no fragments or cracks, and that the idling test is correct before operation;

2. A protective cover must be installed on the grinding wheel of the angle grinder;

3. Protective eyes must be worn during operation, and dust masks must be worn depending on the processing conditions, but gloves are not allowed;

4. It is forbidden to hold the workpiece with your hands to process it with the angle grinder, and it is forbidden to cut in the direction of yourself or other people;

5. No part of the human body may come into contact with moving parts;

6. When replacing the grinding wheel, power-off measures must be taken. After the replacement is completed, a test run is required for 1 minute to confirm that there are no abnormalities.

Finally, although the safety operating procedures, work specifications and other requirements are complicated, they are all the blood shed by others, the injuries suffered, and even the remorse and tears of being jailed for violating the relevant laws and regulations on production safety.

By fully receiving accident warnings, absorbing lessons learned from accidents, and complying with safety requirements, you can avoid making the same mistakes as others to the greatest extent possible.