Drill#Cordless drills

A drill is a motor-driven, drills - like tool for screwing and drilling. Often the devices are provided with a slip clutch which, upon reaching a preselected maximum torque to drive the work spindle decoupled (the motor " rotates through "). Thus, a uniform tightening of screws to ensure the material. With an adjustable depth stop countersunk screws can be screwed surface parallel to the surface.

A cordless drill, cordless screwdriver usually, is a battery- powered tool, be carried out with the drilling and screwdriving applications independently from the mains. Cordless drills are the most popular cordless tools.

Demarcation

There are

• Screwdriver,
• Impact wrench,
• Cordless
• Hammer,
• Pulse ( bohr ) helicopter.

Percussion drilling means that the device has an impact mechanism, which serves to quickly and regularly deliver a blow in the axial direction ( " strike it on the drill along its direction "). This is especially when drilling in hard, brittle material (eg stone, concrete ) are required.

When shock bolts and the similar impulse wrenches generated by a pulse-like ( " hit" ) rotary motion, a higher torque on the screw. The electric motor can overheat the pulse screws without briefly be overloaded, which despite its small size, high torque results.

Drills have spread a two-speed gearbox: Slow for screws, fast for drilling.

Types

In addition to the design in pen style, which is usually smaller dimensions and suitable for simple assembly work, the design has set with T-handle. Older devices do not have a drill like the pistol grip. Some drills are equipped with a small spotlight, the spotlight so-called to work even in dark working environment.

In older cordless screwdrivers usually NiCd or NiMH cells are used, NiMH batteries can be found even at current (2011) devices in the lower price segment. Due to the at that time the low energy density of batteries especially those with NiCd technology are quite heavy and thus restricted in handling. NiMH cells have approximately twice the energy density of NiCd; LiIon batteries can double it again.

Since 2003, lithium - ion batteries are used by many well-known manufacturers that have a much better power to weight ratio. In addition, short loading times and a very low self-discharge.

Quality characteristics

Primary characteristics of a drill-driver are the maximum torque, speed and, at cordless screwdrivers, the capacity of the battery measured in ampere-hours (Ah). Multiplied by the operating voltage ( volts) results in the stored energy in the battery, so that, for high capacity and high voltage long operating time can be closed with a single charge. Therefore, operating voltage and capacity are often postulated as a quality measure.

Less obvious are, for example, Workmanship, high-quality interpretation ( eg storage ), high-quality components used in electronics (eg capacitors ) and mechanics (stable plastic parts), free from hazardous substances (eg PAHs ) and the durability of the batteries (if present ). Important factors for the professional user are also ergonomics, accessories as well as the services of the manufacturer.

Trivia

• Cordless screwdriver races are held with different vehicle designs, which are driven by a single, standard screwdriver.