Puncher Cracks And Does Not Twist How To Fix
A puncher, like any electric tool, requires a careful attitude, proper operation and timely preventive maintenance. If these standards are neglected, then the device may fail without having developed its resource. Repair of the punch in case of some malfunctions can be done by yourself, and to eliminate breakdowns associated with the electrical part of the engine, specialist assistance is required.
The main malfunctions of the punch and their external signs
All malfunctions of the unit can be divided into 2 groups: mechanical and electrical.
If any mechanical malfunction appears in the punch, then its presence can be identify by ear (noise increases, a rattle appears).
You may also experience increased vibration or an unpleasant odor emanating from the unit body.
So, the following can be attributed to mechanical breakdowns:
- Breakdown of the device operation mode switch;
- Worn rubber striker and striker;
- Failure of the shock mechanism;
- Failure of the unit barrel due to wear and tear;
- Gear teeth breakage;
- Breakage of the chuck, as a result of which the drill flies.
Faults associated with the electrical part of the punch, can also be accompanied by an unpleasant odor from the apparatus, sparking. You may also notice that the engine heats up quickly and buzzes, without spinning, or smoke appears from it.
Electrical breakdowns of the apparatus include such as:
- The device does not turn on;
- Breakdown of the start button;
- Brush wear;
- Clogged collector;
- Violation of electrical contacts;
- Burnout of the stator winding or rotor of an electric motor.
Punch Disassembly Algorithm
To eliminate mechanical and electrical problems (with the exception of a broken electric plug), disassembly of the unit casing cannot be dispensed with. The most popular among masters, both home and professional, are the brands of Bosch, Makita, Interskol, Energomash punchers. The design of units of different manufacturers is approximately the same, therefore, the methods of disassembling the devices will be similar. But you should not disassemble the device completely, since it will be difficult to assemble it back. The photo below shows how a fully disassembled punch looks like.
The disassembly of the unit for troubleshooting should be carried out carefully, with an inspection of each removed part. So that the assembly does not cause difficulties, it is better to photograph the disassembly process. If you did not find any external defects on the device, then it is recommended to start disassembling it with a cartridge.
- First remove the boot (1) made of rubber.
- Carefully, so as not to lose, use a screwdriver to remove the snap ring (2) and then a plastic boot (3).
- The next step is not to lose small ball, which is under the washer (4). Remove the washer (4), plate (5) and spring (6), as well as ball (7). It is with the wear of these parts that the drill falls out of the cartridge. Some cartridge models may have extra balls and washers.
Disassemble the case
If disassembly of the unit body is required, then first you need to remove the mode switch.
- Put the switch to the position of “Blow”. Usually a hammer is drawn on this case on this case. If this mode is not available, put the switch in the position “Impact drilling”.
- Next, you should click on the button located on the handle of the switch, and turn it slightly below the icon with the image of a hammer until a distinctive click is heard.
- After that, it is necessary to pry the switch with a screwdriver and pull it towards you, remove it. In some models of units, this switch can be screwed to the housing.
Dismantling the electric part of the punch
To get to the electrical part of the device, if there are suspicions that it may be a malfunction, you must perform the following steps.
- Loosen the screws holding the back cover and remove it.
- Unscrew the fasteners holding the network cable.
- Next, pull out the wires from the mounts and remove the start button.
- Remove all wires attached to the stator.
- Remove the brushes by unscrewing the fixing bolts.
- Separate the enclosures of the electrical and mechanical parts of the apparatus by unscrewing the corresponding bolts. For separation, use “flat ”screwdriver.
- Remove the rotor from the gearbox. If you need to replace the bearings, use a special puller.
- Remove the air intake located in the body of the electric part of the punch.
- Disconnect the stator from the housing. To make it easier to get out of the casing, it is recommended to pull the stator with a light tapping on the body with a wooden object.
If you want to disassemble a barrel perforator, with a vertical arrangement of the electric drive, then the handle is first removed, and then the bolts holding the engine are unscrewed.
Replacing motor brushes
The main sign that it is time to change the brushes is the formation of increased sparking in the area of the electric motor collector, the rapid heating of the brush holders, and the smell of burning. When the brushes are not worn out, the spark can be seen only under them. Otherwise, a spark is visible throughout the collector circle.
The presence of sparks around the collector with worn brushes is a sign of bearing wear, insulation failure of the rotor or stator, burnout of the collector plates, burnout of the stator or rotor.
Another sign that the stator burned out is the presence of sparks under only one electrode. If you have a tester, then they can check stator and rotor: Measure alternately the resistance on the rotor and stator. If it is the same on both windings, then everything is in order with the stator. If you notice that your rotary hammer has obvious signs of problems with the rotor or stator, you will have to carry the device to a service center for repair. As for the brushes, they can be changed independently.
To get to the place where the brushes are installed, you will need to disassemble the case in which the engine is installed, or simply remove the back cover. Opening the cover, you will see the brushes fixed in special holders. The photo below shows how these details look.
The brushes that are installed on the motors of punchers are of 3 types.
- Graphite. Differ in durability, but since they are very hard, rubbing them to the collector is not ideal, which negatively affects the latter.
- Coal. They are easy to grind to the collector, providing good contact, but wear out quickly.
- Carbon Graphite –– an ideal option, as they are a mixture of 2 components that complement each other.
It is very important not to wait until the engine sparkles, and after that change the brushes. Replacement is needed after they wear out 1/3 of the nominal value (8 mm). Even if one brush is worn less than the other, you still need to change both.
Pay attention to the condition of the spring in the new brushes and the fastening of the contact. If the spring flies during engine operation, it will receive significant damage. Also, if the spring is weak, then it cannot provide good contact.
Be sure to change the brushes well before clean rotor and stator from residues of graphite or coal dust. These parts can be cleaned with technical or medical alcohol.
Next, you should fix the electrodes in the holders and grind them to the collector. To do this, put a piece of fine sandpaper on the collector and rotate in different directions to produce lapping electrode. Lapping continues until the contact area of the electrode electrode is rounded. This will ensure its best fit to the collector plates and, consequently, better contact.
The scheme of the device of the percussion mechanism, its malfunction and repair
Impact mechanisms of perforators differ in their design, depending on which family the devices belong to. Therefore, the repair of these mechanisms will occur according to different principles.
Rotary hammers with a vertical arrangement of the engine usually have a shock block based on a crank mechanism (KShM). The following is a diagram of this type of impact mechanism.
The following photo shows the apparatus in a section where you can see the location of the cshm.
The shock mechanism of a unit with a vertical engine may have the following malfunctions. The connecting rod mechanism has a separate bearing that is mounted on the cam of the wheel with an eccentric, but sometimes it can be located at the base of the connecting rod. In some models of rotary hammers, a plain bearing may be installed in this place (instead of a rolling bearing), requiring constant lubrication. If she is not there, or she is already old, then this knot wears out. During the repair, the connecting rod and eccentric barrel will have to be completely replaced.
Another common problem is the striker broke. This malfunction can be calculated if you notice that your hammer is no longer hit. To get to the striker, you will need to completely disassemble the barrel of the device. It is done as follows.
- Disconnect the barrel from the punch body, remove the cartridge (see description above). Tap the barrel on the table so that the piston falls out of it. Take a rubber mallet and knock the barrel out of the body.
- Remove the snap ring holding the bearing.
- Remove the bearing itself and gently tap the table to remove the balls.
- After removing 3 balls, you can pull out the raster sleeve.
- Also, as in the previous case, remove the balls located on the sleeve, but do not confuse them with those that were removed earlier (these balls are smaller in diameter). After removing the balls, you need to insert a screwdriver into the sleeve and push out the striker.
In this case, the whole striker. But if it is broken, then replace it with a new one. You should also pay attention to the sealing gum and the seals in the barrel. If they are worn, they must be replaced.
Pistol Type Hammers
The device of the percussion mechanism of the pistol-type unit is slightly different from the same mechanism intended for use in the barrel-type apparatus.
Its main difference is that the piston does not move with the help of a connecting rod, but from a swinging (“drunk”) bearing. Therefore, the most common failure of this unit is the wear of a “drunk” bearing, which must be replaced.
The following photo shows a destroyed “drunk” bearing, which is the reason that the hammer stopped hammering.
The swinging bearing is removed using a flat screwdriver, which you need to pick up the bracket, and remove it. After that, the bearing is easily separated from the gear housing.
When replacing a collapsed bearing should be good flush gear, since it is in his case that fragments of a broken part can remain.
After cleaning and installing a new bearing, apply a greasy layer of grease to this unit.
Also, the reason that the device does not hit can be a broken firing pin. To get it, you need to remove the snap ring, which is visible in the hole.
Take a small screwdriver, pick up the ring with it, and slide it to the right (towards the gear).
Do the same on the other side of the part. Next, insert a screwdriver into the hole of the part and push the removed internal parts of the mechanism.
After this action, the retaining ring and the housing in which the broken impact striker is located will be easily accessible.
If you disassemble this case, you will see the “culprit” of the malfunction, due to which the hammer does not hammer.
When assembling the impact mechanism, do not forget to generously apply grease to all its parts.
Other mechanical breakdowns and their elimination
In addition to breakdowns associated with the percussion mechanism, other mechanical breakdowns can occur in the hammer drill.
There are times when the unit mode switch fails. This is mainly due to dust clogging this node. To repair the switch, you will need to disconnect it from the housing (see above for how to do this) and clean it from dirt. If you find any damage to the plastic parts of the switch, you will have to replace it.
The reason that the device stopped working normally, namely, stopped drilling and hammering, may lie in worn teeth on the rotor shaft.
If this happens, then the teeth will be worn out and on the intermediate helical gear.
This problem occurs when the tool is jammed or the clutch is malfunctioning. Failure is eliminated by replacing the intermediate gear and motor rotor.
The drill does not hold in the cartridge
The reason that the punch does not hold the drill lies in the breakdown of the cartridge and the wear of the parts included in its composition:
- Ball deformation occurred;
- Restrictive ring worn;
- Fixing spring sagged.
You will need to disassemble the cartridge and replace the problematic parts.
Drill stuck in a punch
The reasons that the drill is stuck in the cartridge of the apparatus may be as follows.
- Before installing the tool, you did not apply grease to its shank. It will be necessary to move the sealing gum of the chuck and inject it into the place of the tool WD-40.
- Dust fell under the balls. Perform the same operation as above.
- If you used a conventional drill inserted into the adapter in a puncher, also process it fluidWd-40, wait a couple of minutes, and, gently tapping the surface of the clamp with a hammer, loosen the equipment in different directions. Typically, after these steps, the clamping jaws open and allow the drill to be removed.
- The tool shank riveted. You will need to first fill in the WD-40 fluid and try to pull out the drill. If all else fails, then you need to disassemble the cartridge and knock out the snap. You can also use the tips on how to get a tool stuck in the device from this.
The horizontal layout is usually used in lightweight perforators, vertical. In medium and languid. But there are exceptions. Heavy hammer drill Metabo KHE 96 with a weight of almost 12 kg has a horizontal motor.
A tool with horizontal assembly is more compact and convenient for working in narrow places. But this design is characterized by an excessive shock load on the engine and somewhat worse criteria for its cooling.
The vertical assembly provides the best engine operating conditions (reduction of shock vibration and effective cooling), as well as a wider amplitude of movement of the piston and hammer due to the ability to use a instead-swinging bearing with a crank mechanism with an increased piston stroke.
Rotary hammers with a vertical motor arrangement can carry more intense work than models with horizontal assembly.
There are two main options for performing shock electro-pneumatic mechanism. Using swing (“intoxicated”) a bearing or a crank mechanism. The first option is used for light and, in part, medium perforators, the second. For medium and languid.
The figure below shows a diagram of a lightweight rotary hammer. Its percussion mechanism consists of a swinging bearing, a piston, a ram and a hammer.
During the operation of the rotary hammer, rotation from the electric motor is transmitted to the inner sleeve of the swing bearing. With all this, its outer sleeve, coupled with a perpendicular axis connected to the piston, oscillates. Between the piston and the ram there is an air place, which, due to the increased pressure and vacuum created alternately here, forces the ram to repeat the oscillatory movements of the piston, striking the striker. The latter strikes the tool in the chuck. Thus, the energy of the electric motor is transformed into the shock energy of the instrument.
Hammer drill cracking and not twisting how to fix? Do not forget to read the description of the!
Pneumatic shock mechanism equipped with a function of self-shutdown at idle. Office, when the tool (drill, drill, crown) is not pressed to the work surface, the ram moves forward, opening a hole in the housing for air inlet and outlet. And therefore, this compression and rarefaction in the working air cavity are not created, the shock mechanism is turned off, and hammer drill works without bumps. When inventory is pressed on the surface to be treated, the hole is blocked by a ram, compression appears in the air cavity, and the percussion mechanism begins to work.
In medium and heavy rotary hammers having a vertical motor assembly, the piston is driven by a crank mechanism. The overestimated amplitude of the piston movement contributes to a higher impact power, which sometimes reaches 20 joules in languid perforators. The operation of the percussion mechanism occurs similarly to that described above.
At the bottom of the article there is a demonstrating the work of the shock mechanism.
The figure below shows the device of a Russian-made perforator Progress PE-40/1050 with a power of 1050 W with a vertical motor and a crank drive of the percussion mechanism. The rotation from the motor through the worm shaft is transmitted to the helical gear, on the shaft in which the crank is required, which drives the piston.
At the end of the article there ares demonstrating the work of the active anti-vibration complex of accounting programs.
In addition, the handle can be additionally responsible for damping the vibration: from the bottom, it is fixed to the body using a hinge, and from above through a spring mechanism. Under the passive anti-vibration system, ordinary rubber pads on the body are assumed, which also protect against slipping hands. But we must admit that the sense of overlays is weakly large.
That, the electronic circuit of the punch can vary significantly among different models, in the most elementary version of its own it is similar to the electronic circuit of an electric drill, which is carefully described in the text of the article Drill device.
As safety in punchers, two types of couplings are used: friction and spring-cam. The first consists of disks in the normal state pressed together and transmitting torque. When the tool is jammed, the disks slip relative to each other, disconnecting the motor shaft from the chuck with the nozzle. Friction coupling used, for example, in Metabo models.
Probably offices use spring-cam type safety couplings. They consist of 2 half-couplings having radially located protrusions and depressions (teeth) at the ends, which are combined in the normal mode. The clamp of the coupling halves between itself is provided by a spring. The principle of action of the spring-cam clutch is based on the slip of the coupling halves relative to each other in this case, if the moment of resistance begins to exceed the clamping force of the spring. In this case, an appropriate crack is heard, signaling that the nozzle is jammed.
It is believed that the spring-cam coupling more reliable than friction, but she certainly has a severe flaw. It consists in the fact that during operation the tips of the teeth are rolled, which leads to the operation of the coupling even in this case, when the nozzle did not jam, but only huge resistance appeared. Some craftsmen cope with this problem by placing a washer 3-5 mm wide under the spring, which increases the compression force of the spring and, as follows, the moment of operation of the clutch. But redundant “hardness” couplings are also undesirable, as it makes the jerk of the tool very strong when jamming the nozzle, which leads to injuries to the hands of people working with the hammer.
Safety coupling or torque limiter
A grease is used to lubricate the gearbox, which is filled into the gearbox during initial assembly and at the time of maintenance or repair. At those moments when the punch is disassembled.
demonstrating a punch device:
Often a tool such as a hammer drill is used in construction or repair work. Therefore, knowledge of how a punch is designed and what is the principle of its operation based on is required for every person using this device. A variety of models and modifications of this tool leads to a large number of differences in its design, however, the general structure of the structure of the hammer drill is preserved for any model.
The scheme of the device punch.
Design features of rotary hammers cause a difference in the power and functionality of the device. All tools of this type have the following components in their design:
- Electric motor;
- Shock mechanism;
Additionally, rotary hammers can be equipped with certain systems that can expand capabilities or make the use of a rotary hammer comfortable. Such systems are:
- Anti-vibration system;
- Work item fixation system;
- Mechanism for fixing the depth of drilling;
- Dust removal system from the work area;
- A mechanism for changing instrument operation modes.
The design of the hammer may differ in the arrangement of electric motors. The tool is of two types: with vertical and horizontal placement of the electric drive.
Electric hammer drill
An electric drive acts as a motor in the construction of the tool. In rotary hammers, collector-type electric drives are used.
Lubrication stages of the punch.
Lightweight rotary hammers used in the farm have horizontal motor placement. In contrast, the middle and heavy class models used in professional activities are usually assembled with vertical placement of the power drive. However, there are exceptions to the rule. So, for example, a Metabo KHE 96 model punch manufactured by Metabo KHE 96 weighing 12 kg, which belongs to the heavy class, has a horizontal electric drive placement system.
The tool, which has a horizontal mounting scheme for the power drive, is compact and convenient for use in hard-to-reach and narrow places. This layout of the hammer drill has several drawbacks, among which the main ones are the presence of a high load on the power component and poor cooling conditions of the electric drive.
A rotary hammer with a vertical installation diagram of the electric power component provides more comfortable conditions for its use. The fact is that the vertical placement of the electric motor reduces the level of shock vibration and provides better cooling of the electric motor. In addition, the vertical layout allows you to give the piston a wide range of motion, which increases the amplitude of movement of the striker. This advantage is achieved by the fact that in the design with a vertical layout of the electric motor layout, a crank mechanism is used instead of the rolling bearing installed in the tool with a horizontal mounting circuit of the electric motor.
Perforators with a vertical circuit are able to withstand continuous operation, which is not available to the tool with an electric motor installed in a horizontal position.
The percussion hammer mechanism is an important tool assembly that is responsible for ensuring that the main function is performed.
The principle of operation of the percussion hammer mechanism.
There are two types of execution of this mechanism:
The electro-pneumatic type of construction of the percussion mechanism is used in most modern perforators. The advantage of this design is the receipt of high impact energy with a small power plant power tool.
There are two design options for an electro-pneumatic impact assembly. One of them uses a rolling bearing, and the second is based on the action of a crank mechanism. The first version of the design is used on perforators of the lung, and the second. On tools of medium and heavy class.
The design of the percussion mechanism of a lightweight rock drill consists of a rolling bearing, piston, ram and hammer. When starting, rotation from the power electric motor is transmitted to the inner race of the bearing. The outer race of the bearing with the piston is a single unit and oscillates.
Three universal operating modes of the punch.
The air space of the cylinder between the piston and the ram experiences a decrease and an increase in pressure. Due to a change in pressure, the ram repeats the movements of the piston and strikes the surface of the hammer, the movements of the latter affect the bit in the cartridge.
The pneumatic version of the mechanism provides automatic shutdown at idle. This function is performed by moving the ram forward in the absence of contact of the bit with the surface. When the ram is displaced, an opening is opened for the movement of air between the external environment and the piston chamber.
In tools belonging to the medium and heavy type, which have a vertical arrangement of the electric motor, the piston is driven by a crank mechanism. The high amplitude of this device increases the impact power, capable of reaching a value of 20 kJ. The principle of operation of the mechanism is similar to the previously presented type. The rotation through the worm shaft is transmitted to the gear. The crank last transmitting the impulse to the percussion mechanism is last fixed on the shaft.
Anti-vibration system used in the tool
Scheme of the main parts of the punch, which often break.
Firms are constantly developing new and improving existing systems aimed at reducing the vibrations arising in the tool. The whole variety of vibration protection systems can be divided into two types:
Active anti-vibration system is mounted only on a tool with high power. To reduce the level of vibration, a simple device is used, which consists of a counterweight with a spring device that accepts all vibration loads. This system cannot fully compensate for all vibrations that occur in the instrument, it only contributes to a significant reduction in its level. In addition, vibration damping is facilitated by a tool handle attached to the body by means of a swivel joint and a spring mechanism.
The role of the passive system to reduce the level of vibration arising in the work is performed by rubber pads mounted on the body, in addition, such pads prevent slipping of hands. Passive system is ineffective.
Electrical diagram and tool body
Lever removal scheme.
There are a large number of ways to adjust the rotation speed of an electric power tool installation. You can adjust the rotation speed by changing the force of pressing the start button. In addition, the rotation speed on some models of devices is set before use by rotating the control knob.
The electrical circuits of various models of rotary hammers can have significant differences among themselves. The simplest wiring diagram of a hammer drill resembles a circuit of an electric drill.
The case for mounting the mechanism is made of metal. As a rule, aluminum or magnesium alloys are used for its manufacture. For light types of tools, housings are made of high impact plastic. Sometimes you can find models in which the manufacture of the case uses both metal and impact-resistant plastic. The metal is much stronger than plastic and contributes to more efficient heat dissipation than provides faster cooling mechanisms.
To provide the device mechanisms with effective cooling, air is used that is captured by the fan wheel mounted on the electric motor, which is sent to the shock mechanism and thereby carries out its cooling. This prevents the tool from overheating during prolonged use. The air flow maintains the optimum temperature of all mechanisms and the metal case, which prevents injuries, in addition, in order to protect against burns in especially dangerous places, various covers made of plastic are attached to the case. There are models in which one side of the case is made of metal, and the second of shockproof plastic.
Safety clutch in tool design
Disassembly of the perforator gearbox: 1. Special ring, 2. Releasing sleeve, 3. Ring, 4. Ball, 5. Spring 8. Casing, 22. Closing spring, 28a. Switch, 29. Ring, 30. Spring, 31. Retainer.
Hammers are equipped with special couplings that perform a safety role in the event of a cartridge stopping when jamming. Jamming threatens to exit the working condition of the punch or to injure a person. To avoid the occurrence of such a situation, the tool is equipped with a special safety clutch. In addition, the coupling is a protective mechanism that prevents the engine from overloading.
If the drill stops due to the presence of the coupling, the motor armature does not stop. The clutch ensures that the perforator cartridge is disconnected from the motor shaft, preventing it from burning out.
Two types of couplings are used in rotary hammers:
The first type of couplings consists of discs that are pressed together in a normal position. When the cartridge stops, the disks slide relative to each other, which leads to the disconnection of the electric motor from the cartridge. This type of coupling is used in the construction of tools manufactured by Metabo.
The spring-cam mechanism includes two coupling halves, which at the ends have special protrusions and depressions. The clamp of the coupling halves is carried out by the spring. The principle of operation is based on the principle of slipping of the coupling halves relative to each other in the event of jamming of the tool. When the mechanism of this type of clutch is activated, a characteristic crack of teeth is heard.
It is generally accepted that the spring-cam system is more reliable than the friction system. The latter has a drawback. During operation, the ends of the protrusions on the coupling halves are rolled, which leads to the operation of the coupling in the absence of jamming of the cartridge.
Rotary hammer gearbox design
A gearbox is required to transfer rotation to the drill chuck. In addition, the gearbox ensures the functioning of the impact mechanism. It includes various types of gears. Gearboxes have a constant gear ratio.
The adjustment of the rotational speed of the perforator cartridge is carried out using a special electronic controller. It is worth noting that to date, models having two-speed gearboxes have been developed and are being produced. Grease is used to lubricate the gears of the mechanism, which is refilled during assembly or during repair.
The scheme of the device components of the punch.
Today in the design of perforators use three types of cartridges. The punch holder may have the following designs:
The latest variety of cartridges is equipped with up to 90% of all manufactured perforators in the construction tool market. The cam chuck is the key chuck of the puncher, in which the nozzle is clamped using a special key, which opens and brings the cams.
The keyless chuck is characterized in that the nozzle is clamped solely by hand force. This type of cartridges has two subtypes. One-coupling and two-coupling. Such cartridges are used on rotary hammers with automatic shaft locking.
The SDS system chuck is quick-clamping and works on the principle “inserted, turned, fixed”.