Which Vertical Rotary Hammer is Better
Any electrician periodically encounters the need to lay electrical wiring inside concrete or brick walls, which have to be drilled or ditched. Performing such tasks is more convenient with a specially designed rotary hammer.
In order to successfully select his model for work, we suggest that you familiarize yourself with the features of various designs and a list of technical solutions for their implementation, embodied in the diverse designs of rotary hammers produced by modern manufacturers.
A perforator is created for making holes in concrete, brick, stone building structures of increased strength by the method of applying mechanical impacts to a nozzle that performs a combined translational-rotational movement.
Additional tasks of the punch are:
1. drilling holes in various materials due to the function of the drill;
2. the application of a long series of axial impacts in the mode of a jackhammer.
Like all modern tools, it is given the opportunity of multifunctionality. Using a different set of special nozzles, they can:
prepare various mortars;
clean the surfaces of metal, stone, concrete;
to do many other work.
How does a hammer drill work
Tools that create holes in the walls of building structures, including perforators, are created with different technical solutions.
How does an impact drill work?
The structural difference from a conventional drill is that during operation it causes a lot of small axial beats due to the use of a mechanical gear device.
The upper part of the shock structure consists of a fixed gear with a complex relief of the contact plane, and the lower part, which receives rotation from the electric motor, is connected to the cartridge of the working body. On its contacting contact end is mounted the same embossed gear, which can:
1. Separate from the top by entering a metal retainer, as shown in the picture;
2. or snuggle up on surfaces.
If the latch is inserted, then it eliminates the contact of relief mechanisms: the drill operates in a smooth drilling mode without performing axial impacts. When the mode of the beating of the cartridge is set by removing the latch, the energy of the electric motor rotates the movable gear along the hollows and protrusions of the stationary one and due to this, axial movements are imparted to the cartridge.
In this case, the user needs to press on the device body and rest it against the drilled part in order to create contact of the disks with embossed surfaces.
How to strike with a puncher
To give axial displacements to the working body, two types of drive mechanisms are used:
The shock action of the first method is based on the interaction of two coils forming oppositely directed electromagnetic fields that are created at different points in time and act on the core, forcing it to cyclically move back and forth. At the same time, he strikes at the end face of the working body.
Most often, the designs of modern rotary hammers use an electropneumatic actuator. He axial movement of the working body occurs due to the application of direct strokes of the piston at the end of the head. In this case, one of two technologies is used:
1. the mechanism of "drunken bearing";
2. The design of shock crank.
In both designs, the piston moves inside the airspace bounded by the cylinder between the pusher hammer striking it and the end face of the working body. In this case, the air is compressed by the piston and transfers energy by a sharp blow.
After that, the piston bounces, and the pusher, returning back, quickly creates an additional vacuum in front of it.
Depending on the design of the mechanisms, the piston performs translational-reciprocal movements with different frequencies and transfers the energy of the pusher to the working body without a rigid mechanical connection between the electric drive and the actuator (through an intermediate air medium).
Due to this technique, the impact of the working body requires less power application than an electric drill. Therefore, perforators work more efficiently, consuming less energy in the surface chiselling mode.
For safety reasons, pneumatic percussion mechanisms are usually equipped with an idle shut-off function when the working body is not pressed against the work surface.
Rock drills with swing bearings
These designs use the transmission of movement to the piston follower due to the mechanism of the swinging “drunk” bearing, which receives rotational energy from the electric motor and converts it into axial impacts.
To do this, a support bearing of the working shaft is mounted on the drive sleeve worn on the lever. A protective cover is installed inside the outer and inner rings of the cage, covering steel balls. swinging bodies.
A groove is located on the shaft, acting as the inner ring of the bearing. Due to this technical technique, the lever oscillates only in the axial direction, pushing the piston.
The number of reciprocating oscillations of the nozzle is directly proportional to the speed of rotation of the engine rotor, and the amplitude of movement is affected by:
design of the maximum angle of inclination of the bearing to the shaft axis;
leverage length used.
The location of the engine in a perpendicular plane to the axis of movement of the working body allows you to use a simple crank mechanism for reliable operation of the hammer.
Due to the crank, the rotational movement of the engine is converted into a reciprocating oscillation of the pusher, and the latter makes periodic strokes on the piston.
How rotation is attached to the nozzle
In order for the working body in the cartridge to carry out, in addition to impacts, rotational movement in the design of the perforator, mechanisms are used that transmit the rotation of the nozzle from the engine. One way to implement this method is shown in the picture.
Video: Which Vertical Rotary Hammer is Better
Chain transmission and bevel gears work in models with a vertical arrangement of the engine.
What to consider when choosing a hammer drill
All models according to their technical capabilities are classified into three main groups:
1. household appliances, allowing at home to carry out various repairs from time to time;
2. professional designs designed for continuous daily use for eight hours of a working day;
3. industrial devices capable of continuous long-term operation, taking into account the shift use by various workers.
The quality of the performance of mechanisms, the perfection of operational algorithms and the comprehensive optimal ratio of tool parameters providing a long time between failures without interruption in work distinguish manufacturers who create a reliable and high-quality tool.
According to the type of energy used, perforators are divided into:
The most popular and in demand are electrical appliances. We will consider them further, specifying that they can receive power from:
1. fixed network;
Cordless rotary hammers operate on battery power:
Main technical characteristics of rotary hammers
When choosing any model, you need to pay attention to four factors:
1. drilling speed;
2. engine power consumption;
3. the power of a single mechanical shock along the axis of the nozzle;
4. rotation speed of the working body.
Strike energy The puncher is considered its main characteristic. It depends on many factors, including the mass of the striker, its stroke length, oscillation frequency and other parameters.
The ultimate capabilities of any model to create enlarged holes in solid materials depend on the generated impact energy. When it is not enough, the productivity of the tool decreases sharply, and the mechanisms work for wear. For this reason, the recommended loads must not be exceeded.
The impact energy developed by the puncher does not depend on the force pressing it, like a drill. Therefore, it is impossible to exert excessive pressure on it, otherwise the tool may be broken.
The impact energy during operation must be combined with the capabilities of the working nozzles. Even carbide inserts can be damaged by high power tools.
Beat frequency characterizes the number of vibrations of the hammer per minute and affects the drilling speed.
According to the location of the electric motor, perforators are divided into devices:
1. horizontal direction;
2. vertical design.
Models with a horizontal engine have less power and belong to the class of light ones, and with a vertical one they are able to withstand increased loads, but have larger dimensions and weight.
Horizontal rotary hammers
These designs are created to work in one of three modes:
1. combined impacts with drilling;
2. rotation without blows;
3. single strokes without rotation of the working body.
Separate simplified devices can only be equipped with the first two functions. Recently, part of professional models, manufacturers began to be produced without the implementation of a drill mode. They are not used for drilling, because most professionals have a drill or screwdriver in their arsenal.
Such lightweight rotary hammers have the following specifications:
consume power up to 750 watts;
inflict from 500 to 1000 beats per minute with a force of up to 3 joules;
possess an adjustable speed of rotation of the drill up to 1100 rpm.
Of the controls, they are supplied with:
convenient front handle with adjustable installation for reliable holding the tool with two hands;
focus to adjust the depth of the hole;
trigger switch with a button for fixing the operating mode of the engine and speed controller;
reverse switch for changing the direction of rotation of the rotor;
indicator of operating modes.
You can adjust the speed of rotation of the working body due to the different pressure forces on the power button.
Vertical rotary hammers
They even look different from previous analogues, immediately distinguished by their power, have all operating modes and full-fledged controls, are capable of inflicting from 1000 to 2000 beats per minute by the working body.
Such models are often equipped with anti-vibration protection of the user’s hands and are created with ergonomic handles that increase the convenience of work in difficult conditions.
Advanced rotary hammers have built-in protection inside the kinematic scheme from damage to the mechanism and causing injuries to a working person. It is performed by a clutch limiting the moment of rotation during jamming of the drill.
Electronic immobilizer on such models and service indicators, for example, the quality of the condition of the brushes, are a sign of brand characteristics.
Some types of rotary hammers are equipped with a two-speed gearbox.
Industrial designs may include a vacuum dust removal system built into the body and kinematic scheme or made by a separate, removable unit. A built-in drive can be mounted inside it or the energy of the air flow from the cooling fan impeller can be used.
The working tool is inserted into a special holder due to the axial squeezing of the cartridge head towards the housing.
In this case, the cartridge works in two positions:
In a closed version, the spring system presses the mounting tabs inside the grooves of the nozzle shank. To remove the working body, just press or rotate the retaining ring located on the cartridge case. In this case, the petals diverge, and the nozzle is freely removed from the nest.
The fastening of the working bodies is carried out by cartridges of various designs:
The abbreviation SDS stands for the special design of the cartridge guide system, which works according to the principle: insert-turn-drill installed, which was created by Bosch.
SDS Shank has a diameter of 10 mm, two grooves and is recessed into the cartridge by 40 mm. It is fully compatible with the SDS plus cartridge and works great in it.
SDS-plus designs it is installed on all household and part professional punchers. They differ from the previous brand not by two, but by four diametrically located grooves. Guide wedges go into two open of them, and lock balls go into two closed ones.
Shanks of this brand are installed on drills with a diameter of 4 ÷ 26 mm and a length of 110 ÷ 10000 mm.
SDS-top standard It is designed for medium-sized punchers with a shank diameter of 14 mm and a chuck 70. It is an additional development for medium-sized punchers to drill larger holes with diameters of 16 mm or more, since it solves the problem of breaking SDS-plus shanks. But, under them on the punch you need to change the cartridge. Because of this, they are not in great demand.
Ammo SDS max Hammers with increased power are supplied. They are fixed working bodies with a diameter of 18 mm. For a 90 mm deepened shank, two closed and three open slots work in the chuck shank.
SDS-quick standard uses not grooves on the shank, but protrusions. This prototype model is used only on special Bosch Uneo rotary hammers.
SDS-hex Specially designed to hold chisels and peaks firmly in jackhammers, although it also works well with drills.
Spline is an analogue of the SDS-max shank. It is widely used on rotary hammers manufactured for North America.
Most rotary hammer sets come with a factory-fitted cam chuck, which can be inserted as an extra part or completely replaces the SDS design. This allows you to use the drilling mode with conventional drills with round cylindrical shanks designed to work in conventional drills. These cartridges are commercially available.
On elite models of rotary hammers there is an improved dustproof cartridge.
Types of accessories for the punch
When working, you may need:
drills of various lengths with various tips to create punching holes;
peaks for knocking out horizontal deep grooves;
blades for chipping tiles or other facing materials, firmly held on the foundations of building surfaces;
special nozzles for making round holes.
For proper and careful use of the tool before inserting the working body into the cartridge, it is necessary to lubricate this place with special grease. This technique prevents premature wear of the hammer and prolongs its technical life.
Each hammer drill requires careful handling. It should be stored in a prepared place, kept clean, timely replacement of worn carbon brushes, lubricated chassis.
Periodic inspection and constant care significantly extend the life of any mechanism.
Each of their models can perform a wide range of tasks, has various amenities, but at the same time it is best suited for working in any specific conditions.
Therefore, when choosing a punch, you should consider its capabilities and compare with the tasks for which it is purchased. Pay attention to features such as:
the capabilities of electronics to limit inrush currents and protect against overheating at the beginning of drilling and sudden changes in workloads;
blocking from impacts when processing wood or steel;
torque limitation when jamming the rotor;
adjustment of rotation speed, quantity and force of blows;
reverse, allowing you to release the working body when jamming or use a hammer to turn the screws.
We hope that you understand. we cannot give an answer to the question which model of a punch is best suited for your conditions. Make your own choices based on our recommendations.