What are Rotary Hammers?

The electric hammer is an electric rotary hammer drill with a safety clutch attached to a pneumatic hammer mechanism. Electric hammer is based on the principle of piston movement. Compressed gas impacts the drill bit. It does not require much force by hand. It can open 6-100 mm holes in hard materials such as concrete, brick, stone, etc. Higher, but it cannot make holes in the metal.

Electric hammer is a widely used power tool. The electric hammer is based on an electric drill. A piston driven by a crankshaft connecting rod is driven by a motor to compress air in a cylinder to reciprocate the air pressure in the cylinder periodically. The changed air pressure drives the hammer in the cylinder to reciprocate. Hitting the top of the drill is equivalent to hitting the drill with a hammer. Former Electric Hammer ^[1]

1. Good shock absorption system: It can make the operator comfortable to hold and relieve fatigue.

Way to achieve: through "vibration control system"; through soft rubber handles to increase grip comfort;

2. Accurate speed switch: The speed is low when the switch is touched, which can help the machine to start drilling smoothly (such as drilling on a smooth surface such as tiles, which not only prevents the drill bit from slipping, but also prevents the drill hole from breaking. Normal work High speed can be used to ensure work efficiency.

3. Stable and reliable safety clutch: Also known as torque limit clutch, it avoids transmitting large torque reaction force to the user due to the stagnation of the drill bit during use, which is a kind of safety protection for users. This feature also prevents the gear unit and motor from stopping.

4. Comprehensive motor protection device: In use, granular hard objects will inevitably enter the machine (especially for drilling upwards on the machine, such as drilling on the top of the wall). If the motor does not have a certain protection, rotate at high speed It is extremely easy to be hit or scratched by hard objects, which will eventually cause the motor to fail.

5. Forward and reverse function: It can make the electric hammer more widely used. Its realization form is mainly achieved by switching or adjusting the position of the carbon brush. Generally, big-name tools will use the adjustment of the position of the carbon brush (rotating brush holder). The advantage is that it is easy to operate, effectively suppresses sparks to protect the commutator, and extends the service life of the motor.

6.Double function of hammer drill

The advantages are high efficiency, large hole diameter and long drilling depth.

The disadvantage is that the vibration is large, and it has a certain degree of damage to surrounding structures. The steel bars in the concrete structure cannot pass smoothly. Due to the requirements of the working range, they cannot be too close to the building.

The principle of the electric hammer is that while the driving mechanism drives the drill bit to rotate, there is also a reciprocating hammering motion in a direction perpendicular to the rotary head. The electric hammer is driven by a transmission mechanism to reciprocate compressed air in a cylinder. The periodic change in the air pressure in the cylinder drives the hammer in the cylinder to hit the top of the brick back and forth.

Personal protection when using an electric hammer

1. The operator should wear protective glasses to protect his eyes. When working with his face up, wear a protective mask.

2. Plug earplugs for long-term operation to reduce the impact of noise.

3. After a long-term operation, the drill is in a hot state. Pay attention to burn the skin when changing.

4. The side handle should be used during operation to operate with both hands to prevent the reaction force from spraining the arm during stall.

5. When standing on a ladder or working at a high place, take measures to fall from a high place. The ladder should be supported by ground personnel.

Matters needing attention before operation

I. Inspection before operation should meet the following requirements:
1. There are no cracks or breaks in the shell and handle;
2. The cable cord and plug are intact, the switch operates normally, and the protection zero connection is correct, firm and reliable;
3. All protective covers are complete and firm, and the electrical protection device is reliable.
2. After the machine is started, it should run without load. Check and confirm that the machine linkage is flexible and unobstructed. When operating, the afterburner should be stable and not excessive.
3. During the operation, you should grasp the handle of the electric drill or hammer. When punching, first press the drill bit against the special rivet working surface, and then start it with moderate force to avoid shaking. If the speed drops sharply, reduce the force to prevent the motor from overloading. Carry pressure.

First, electrical failure

The electrical fault of the electric hammer is mainly open circuit, short circuit, grounding, and the rotor commutation ring sparks are large.

The fault of the open circuit is mostly a broken wire, of which the broken wire is the most common at the root of the handle. Such a break has a characteristic that the power line of the hammer is connected to the resistance of the multimeter. At the root of the movable leather cord, the reading of the multimeter will change. In addition, the root of the plug is also easy to break, and the switch is broken. There are many cases where the switch uses a multimeter to check the poor contact of the carbon brush. There are two methods for carbon brushes and poor contact:

The first observation is that if the end face of the carbon brush is smooth, the contact is good, and the contact of the hemp surface is poor. Another inspection method is to connect the test lead of the multimeter to the motor end, and use two screwdrivers to press on the brush socket and the rotor at the same time. bad. If the stator earrings are blown out, the motor may be disconnected.

The rotor is also sometimes disconnected. The characteristic is that the power cord is connected to the multimeter. Turn the rotor slowly, and the reading will change greatly. Grounding is generally caused by the stator and rotor rubbing iron. The rubbing of the iron needs to be changed. The rotor, the other is the drying caused by water or moisture. Rotor sparks are generally caused by rotor failure and need to be replaced Rotor, it is necessary to observe whether there is iron rubbing after the rotor is replaced. There is a rattling sound when the iron is seriously turned on. If the iron is light for a long time, the burnt smell current will also rise accordingly. , The screws that fix the stator are loose, the bearing seat is too loose, the stator shell is deformed, and the bearing is damaged.

Mechanical failure

The main failure of the mechanical part of the electric hammer is non-shock and weak impact. The main reason for the non-shock is the aging of the rubber ring on the piston and the hammer. Stand up the big cylinder with the mouth facing down. If the hammer can fall freely, then The rubber ring must be aging. When the rubber ring is aging, you can hear the sound of the piston and the hammer striking each other. After disassembling, you can find that the end faces of the piston and the hammer are shiny. Short impact seeds can also cause no impact. Compare the new shock seeds)

Oil-free can also cause weak impact. If the above conditions are normal and there is no impact, then you must carefully observe the large cylinder to see if there are cracks, and the cracks need to be replaced.

If the motor rotates after turning on the machine, the hammer head can't hear the compressed sound, it may be that the connecting rod is broken or the eccentric is broken. If the motor rotates after turning on the machine, the hammer head does not rotate and there is no compression sound. It may be that the first wheel is damaged or the rotor shaft is broken. Then there is the bad performance of the umbrella teeth which turns into weakness or does not turn at all.

There is another phenomenon that asks you to pay attention to, that is, the key is broken. When we check the cooperation between the gear and the shaft, due to the strong friction between the shaft and the gear glue, it is not easy to find the break of the key, but it will not work properly with the load.

Before replacing the new parts, we must clean up the stolen goods and oil in the fault point so that we can find other faults.

The needle roller bearings in the middle cover must be used well. If defective products are used, they can easily damage both the primary wheel and the shaft of the rotor.