In the 60s, along with the battery technique of manufacture's development, appeared has made power source's non-power line's battery type power tool with the nickel cadmium cell. But because the price was at that time expensive, the development is slow. To the 70s mid and late part, because the battery price reduces, the duration of charging also reduces, this kind of power tool in Europe and America, Japan obtains the widespread use.
The power tool uses the cast iron to make the outer covering at first, latter changes to the aluminum alloy to make the outer covering. In the 60s, the thermosplastic engineering plastics obtains the application on the power tool, and has realized power tool's double insulations, has safeguarded power tool's operational safety.
As a result of electronic technology's development, also presented the electronic velocity modulation power tool in the 60s. Part composition electronic circuits and so on this kind of power tool use thyristor, the depth which presses into are not come together by the switch key button the governed speed, thus causes the power tool at the use time can according to process the object (for example material to be different differently, hole diameter size and so on), chooses the different rotational speed.
The power tool mainly divides into the metal removal power tool, the attrition power tool, the assembly power tool and the railroad uses the power tool. The common power tool has the electric drill, the grinding machine, the electric wrench and the electrically operated screwdriver, the electric hammer and the impact electric drill, the concrete vibrator, the electricity digs.
①Elect ric drill: The main specification has 4, 6, 8, 10, 13, 16, 19, 23, 32, 38, 49mm and so on, the digit refers to the tensile strength is in the 390N/mm steel products the drill hole drill bit most large diameter. To material biggest hole diameters and so on non-ferrous metal, plastic may compared to the original specification big 30~50%.
②Grind ing machine: Carry on the grinding with the grinding wheel or the grinding pan the tool. Has straight to the grinding machine and the electrically operated angular orientation polishing engine.
③Elect ric wrench and electrically operated screwdriver: Uses in loading and unloading the thread joint. Electric wrench's transmission system is composed of the planet gear and the ball bearing spiral groove impact mechanism. The specification has M8, M12, M16, M20, M24, M30 and so on. The electrically operated screwdriver uses the claw clutch transmission system or the gear drive, the specification has M1, M2, M3, M4, M6 and so on.
④Elect ric hammer and impact electric drill: Uses on the concretes, the brick wall and the building unit the perforation, the slot, damages. The union plug bolt use, may enhance each kind of pipeline, the engine bed equipment to install the speed and the quality.
⑤Concr ete vibrator: Uses in the concrete foundation and when the reinforced concrete component the compressed concrete, eliminates the blowhole, enhances the intensity. And the electrically operated straight association-like vibrator's high frequency disturbing force leads eccentric revolving by the electric motor to form, the electric motor supplies power by 150Hz or the 200Hz intermediate frequency power source.
⑥The electricity digs: Uses in shaping the lumber or the wood construction, installs may also make the small stations in the gantry to dig the use. The electricity digs cutter bar by electric motor revolution axis through belt transmission.
①ⅠKind of tool safety protection: In the tool is equipped with the grounding, in the insulation structure completely or the most spots has the basic insulation. If insulation damage, because may touch the metal parts and installs through the grounding in fixed line's protective earthing (sees earth) or the protection meets zero wire coupling in together, does not send into the charged body, may prevent the operator to receive an electric shock.
②ⅡKind of tool safety protection: This kind of tool's insulation structure is composed of the basic insulation and the additional insulation constitution's double insulations or the reinforced insulation. When basic insulation damage, the operator separates by the additional insulation and the charged body, does not send receives an electric shock.ⅡA kind of tool must use may not the reconnection attaching plug, does not permit the earth.
③ⅢKind of tool safety protection: This kind of tool supplies power by the safe voltage power source. Between the safe voltage instruction body or any conductor and the place the no-load voltage effective value does not surpass 50V; To the three-phase power source, between the conductor and the median line no-load voltage effective value does not surpass 29V. The safe voltage usually or has the independent winding's converter supplies by the segregation of security transformer.ⅢOn a kind of tool does not permit the establishment protective earthing device.
④Radio jamming suppression: Brings commutator's single-phase series motor and the direct-current electrically operated opportunity to the television, the radio has the serious electromagnetic interference, therefore power tool in design time must consider that quenches to the radio disturbance.
Mainly uses the shield, the exciting winding symmetrical joint, the establishment electricity filter, the filter to meet measures and so on Cheng △xing. When necessity, but may also serially connect the small inductance coil in the motor armature both sides.