It is very difficult to imagine a modern set of repair and construction equipment without a perforator. Its main function is to punch holes in building materials such as brick, concrete and stone. This power tool is almost always operated in difficult conditions with strong dusting and heavy loads. Therefore, sometimes even the highest quality models fail, not to mention cheap Chinese fakes. If suddenly your punch has broken, do not be upset, because in most cases you can fix the malfunction yourself.
Figure 1. Schematic of the punch device.
The device and principle of operation of the hammer
To understand how to fix a hammer drill in case of breakage, you need to know its device and principle of operation. This tool can work immediately in 3 directions:
- drill various holes in concrete and brick, like a drill;
- ditch grooves in soft plaster, like a jackhammer;
- screw in screws like a screwdriver.
Different models of rotary hammers may differ among themselves in some design features and additional functions. However, despite all the differences, such products have the same components and systems that allow perforators to perform their main function. These nodes include (Fig. 1):
- Electrical engine;
- gearbox;
- cartridge;
- shock mechanism.
Figure 2. Scheme of the pneumatic impact mechanism.
There are also additional components that simplify the operation of the punch. These include: anti-vibration system, a mechanism for fixing the tool in a certain position, a device for switching various operating modes, a system for limiting the depth of drilling, etc.
One of the main elements of the punch is a percussion mechanism, which can be of electromagnetic or pneumatic type. In the first case, the operation of the percussion mechanism is controlled by 2 electromagnetic coils, which create reciprocating movements of the core, and the core transfers these shocks to the end part of the tool. In the second case, the mechanism is ensured by the movement of the piston in the cylinder. It is this type of shock mechanism that is most widely used.
The device of a pneumatic impact mechanism is shown in Fig. 2, where: 1. swing bearing, 2. piston, 3. ram, 4. hammer, 5. gear. When the tool is turned on, the rotational moment from the electric motor is transmitted to the oscillating bearing, which, converting the rotational motion into oscillatory, transfers it to the piston. Due to the pressure differential between the ram and the piston, the first begins to move, bringing the buoy into operation. The buoy hits the working element installed in the cartridge. According to this principle, the conversion of electrical energy into shock is carried out.
The main causes of damage to the hammer
The main difference between a hammer and many other construction power tools is work in heavy dust. Its engine is cooled by a fan. There are many dust particles in the cooling air, which, penetrating the instrument, rub against the anchor and stator, which leads to their rapid wear. To extend the life of these elements, it is necessary to periodically clean them from dust.
Video: Makita Rotary Hammer Doesn’T Work
Figure 3. Stator circuit.
Another frequent breakdown of the tool is associated with a mechanism for switching operating modes (rotation, battle, rotation with battle). Therefore, if your rotary hammer does not turn on, for example, the rotation mode, then you should disassemble the tool and visually check the switching mechanism.
Quite often, the breakdown of the punch is associated with the cartridge, because it is subjected to heavy load during operation. You can protect your equipment from such damage by periodically cleaning the cartridge from dust and dirt with a rag dipped in gasoline.
DIY punch disassembly
The elimination of almost any malfunction in the punch requires disassembly. Therefore, it is very important to know how to do it correctly. The sequence of disassembling the punch is as follows:
- the rubber tip, the annular spring, the drill fixing clutch cover are removed;
- the fixing ball is removed;
- the handle of the switch is dismantled, for which it is necessary to turn the mode switch to the extreme position, and then press the locking button located on it;
- the back pad on the handle is dismantled, the engine brushes are removed;
- 4 screws are unscrewed from the side of the drill and the tool body is removed;
- the rotor of the electric motor is removed, 2 screws are loosened, with the help of which the stator is fixed, after which the stator is removed (Fig. 3).
After replacing the damaged element, the assembly is performed in the reverse order.
DIY punch repair
The main components of the punch.
To repair the punch, you may need the following tools and materials:
If you are more or less versed in the design of the punch, then this will allow you to quickly find the breakdown and fix it with minimal financial investment. Typically, repairing this tool comes down to replacing a failed part:
- Anchors
- starter;
- brushes;
- bearings;
- power cable;
- circuit breaker.
It should be noted that it is much easier to repair a perforator of a household level than a professional one. But the breakdowns of more serious equipment can be quite complicated, so it’s better to entrust them to specialists.
Sometimes it happens that when the punch is turned on, the electric motor does not start. Typically, the cause of such a breakdown is damage to the power cord. Often it is bent at the point of its entry into the tool body.
To eliminate this malfunction, it is necessary to disassemble the puncher and the tester to ring 2 cores of the cable. If a break is detected at any place, the power cord must be replaced with a new one. Twisting is recommended not to be done, since there is a high probability that the cable in this place will break again after a while.
If during operation the motor does not develop full revolutions or during operation a crack and smell of burning are heard, then this may be due to wear of the brushes. In this case, the brushes should be replaced. To do this, you need to disassemble the punch, get the worn out brushes, and install new ones in their place. Another reason for the strong sparking of the brushes may be a breakdown of the stator or rotor winding. In this case, failed parts should also be replaced.
How to extend the life of the hammer?
The service life of this tool largely depends on the correctness and timeliness of its maintenance, proper preparation for work, and also on compliance with all storage and operating rules.
Before turning on the punch, you need to check the reliability of fastening of all case elements, the insulation of the plug and power cable.
When operating the equipment, attention should be paid to external noise, the smell of burning and strong vibrations. When they appear, you should immediately perform maintenance, identify and repair the malfunction.
Continuous work of the punch should not be more than 15 minutes, after which a break should be made for at least 5 minutes. Before replacing the working element (drill, drill, chisel), the tail must be lubricated. It is allowed to change the operating modes of the perforator with the corresponding switch only after the motor stops completely.
Compliance with all recommendations for the use of a hammer will save him from failure, and you from a headache.