The Difference Between An Impact Screwdriver And A Non-Impact Screwdriver
How to use a screwdriver? 5 basic rules How to use a screwdriver correctly. Prepare it for work, install attachments, charge the battery, operate it safely and for a long time.
How to store a screwdriver
Better separate from the battery. If you have a model with a nickel-cadmium battery, then before ending work and disconnecting the battery, it must be completely discharged. After removing the battery, it must be charged. Remember that Ni-Cd has a high self-discharge current, therefore, during long-term storage, it needs to be recharged periodically.
How to use a screwdriver? 5 basic rules
The screwdriver has become one of the most popular when working on the decoration of premises. This is explained by the widespread use of wall panels, suspended ceiling ceilings, and the use of wooden slats as cladding material. These works require massive use of screws and a screwdriver to screw them into the surface. Therefore, the issue of correct operation of the device so that it works for a long time and reliably is relevant. In the article we will talk about cordless screwdrivers as the most popular type of this tool.
Scheme, device, repair
Without a doubt, the power tool greatly facilitates our work, and also reduces the time of routine operations. All kinds of self-powered screwdrivers are now in use.
Consider the device, the schematic diagram and the repair of the battery charger from the firm’s screwdriver “Interskol”.
First, let’s take a look at the schematic diagram. It is copied from a real charger PCB.
Charger PCB (CDQ-F06K1).
The power section of the charger consists of a GS-1415 power transformer. Its power is about 25-26 watts. I counted using a simplified formula, which I have already spoken about here.
The reduced alternating voltage 18V from the secondary winding of the transformer is fed to the diode bridge through the fuse FU1. The diode bridge consists of 4 diodes VD1-VD4 type 1N5408. Each of the 1N5408 diodes withstands a forward current of 3 amperes. The electrolytic capacitor C1 smooths out the voltage ripple downstream of the diode bridge.
The basis of the control circuit is a microcircuit HCF4060BE, which is a 14-bit counter with elements for the master oscillator. It drives a pnp bipolar transistor S9012. The transistor is loaded on the S3-12A electromagnetic relay. On the U1 microcircuit, a kind of timer is implemented, which turns on the relay for a given charge time. About 60 minutes.
When the charger is connected to the network and the battery is connected, the contacts of the JDQK1 relay are open.
The HCF4060BE microcircuit is powered by the VD6 Zener diode. 1n4742a (12V). The zener diode limits the voltage from the mains rectifier to 12 volts, since its output is about 24 volts.
If you look at the diagram, it is not difficult to notice that before pressing the button “Start” U1 HCF4060BE microcircuit de-energized. Disconnected from the power supply. When the button is pressed “Start” the supply voltage from the rectifier is fed to the 1N4742A zener diode through the resistor R6.
Further, the reduced and stabilized voltage is supplied to pin 16 of the U1 microcircuit. The microcircuit starts to work, and the transistor also opens S9012, which she controls.
The supply voltage through the open transistor S9012 is supplied to the winding of the JDQK1 electromagnetic relay. The relay contacts close and supply voltage is applied to the battery. The battery starts charging. Diode VD8 (1N4007) bypasses the relay and protects the S9012 transistor from a reverse voltage surge that occurs when the relay coil is de-energized.
The VD5 diode (1N5408) protects the battery from discharge if the mains supply is suddenly turned off.
What happens after when the button contacts “Start” open? The diagram shows that when the contacts of the electromagnetic relay are closed, the positive voltage through the diode VD7 (1N4007) is fed to the Zener diode VD6 through a damping resistor R6. As a result, the U1 microcircuit remains connected to the power source even after the button contacts are open.
The design of the charger from the screwdriver
The GB1 replaceable battery is a unit in which 12 nickel-cadmium (Ni-Cd) cells, each 1.2 volts, are connected in series.
In the schematic diagram, the elements of the replaceable battery are circled with a dotted line.
The total voltage of such a composite battery is 14.4 volts.
A temperature sensor is also built into the battery pack. In the diagram, it is designated as SA1. In principle, it is similar to the thermal switches of the KSD series. Thermoswitch marking JJD-45 2A. Structurally, it is fixed on one of the Ni-Cd cells and fits tightly to it.
One of the terminals of the temperature sensor is connected to the negative terminal of the storage battery. The second pin is connected to a separate, third connector.
Impact or non-impact screwdriver: what to choose and in which case
The main feature that favorably distinguishes a screwdriver from a drill is its compactness and the ability to work independently. A few years ago, the operating time of the device without recharging was relatively short, but today, after the appearance of more capacious and energy-efficient batteries, manufacturers were able to significantly increase the mobility of screwdrivers and provide them with new functions. One of them is the percussion mechanism. Which is better. An impact or non-impact screwdriver, and what criteria should be used to choose this tool.
Pros and cons of an impact screwdriver
If you tried to drill concrete with an ordinary screwdriver, then you probably know how long, time consuming and thankless it is. An impact screwdriver easily copes with such a task, gives an advantage in working with brick and masonry, but still its effectiveness is far from the capabilities of a full-size impact drill and, moreover, a hammer drill. But in tightening screws and screws “with an interference” impact screwdriver has no equal.
In addition, the tool makes it relatively easy to unscrew fasteners with a damaged cross or partially erased edges. Do not forget that with long-term continuous operation, the percussion instrument does not load the wrist as much as the unstressed one.
However, the impact design can create a number of inconveniences:
- The pusher mechanism is subject to rapid wear, which is especially evident in inexpensive models.
- With the transition to the shock mode, the operating speed decreases significantly, while the noise level, on the contrary, increases.
- An impact driver cannot be equipped with such useful accessories as a cam chuck (almost always hexagons are used) and a torque limiting clutch.
Features of a shockless design
It is known that the simpler the design, the more reliable it is. Due to the absence of constant alternating loads, the chucks and rotors of shockless screwdrivers are less susceptible to wear. Add to this the relatively low cost, small dimensions and weight, longer operating time without recharging. And we get a number of obvious advantages over a percussion instrument. So, if the main task of the device is to work with wood and soft brick, screwing and unscrewing serviceable fasteners under light loads, then preference should be given to a non-impact screwdriver.
Problems will arise when the owner of the tool has to face difficult tasks. The main drawback of a hammerless tool is its almost complete uselessness in drilling hard inelastic surfaces, such as concrete or stone. When working with damaged or hard-wired fasteners, there is a high risk of damage to them. The working head will simply rotate in the crosspiece or on the hexagon without doing any useful work.
Impact screwdriver benefits
By purchasing this power tool, you greatly facilitate your work at home or in the workshop, and on a production scale it is simply irreplaceable.
Let’s consider the main advantages of the tool:
Impact drill screwdriver HITACH
- It completely replaces the screwdriver;
- Using an impact screwdriver, you can tighten or unscrew any nuts and screws;
- If necessary, drill wood or even metal or concrete;
- The device is much more compact and easier to use than, for example, a drill;
- This type of power tool is equipped with an adjustable clutch, which allows you to limit the torque and avoid damage to the fasteners;
- There is no need for strong pressure when tightening screws or screws, which allows you to save their caps and then it will not be difficult to unscrew them if the need arises;
- High wear resistance of the tool;
- The possibility of installation in hard-to-reach places due to the compactness of the device.
Benefits of Impact Screwdrivers (Impact Wrenches)
- High torque! For most cordless models, the torque range is between 80 and 250 Nm!
- Convenient for tightening nuts. At low loads, the tool works in shockless mode with continuous force (quickly tightens the nut along the free thread), and with an increase in resistance, it switches to shock mode (tightening with a high torque).
- There is no need to apply a large pressing force to the tool when tightening screws and self-tapping screws, thereby saving the caps from “licking”. It can also be used to unscrew those screws and self-tapping screws, the caps of which have already begun to bully.
- Reduces torsional stress on the operator’s wrist.
Differences between a traditional drill and an impact type screwdriver
Before many craftsmen who choose tools for home use or for work, the question arises, what is the difference between the not yet well-known impact-type screwdriver and the usual standard electric drill. With a similar appearance, the main difference is the principle of operation:
- In the first case, the tool has an impact mechanism, which drives the drill, while increasing the torque;
- A standard electric drill is based on a two-stage gearbox.
This distinction is beginning to show itself, giving an advantage to the percussion type tool when working on hard and particularly difficult surfaces. When the drill senses resistance, it sends out a series of powerful and quick blows that multiply the torque and make it much easier to tighten the fastener.
It is also worth distinguishing between an impact screwdriver and a drill. With the same principle of operation, they have a different direction of impact. For a drill, this is longitudinal, and for a screwdriver, it is perpendicular to the direction of rotation. The process of action of the tool is most clearly represented as small blows with a wrench while tightening the nut.