Electric tubing - Drawings

Contents

Introduction

A manual is called a technological machine equipped with a built-in engine, during the operation of which the mass of the machine is fully or partially perceived by the hands of the operator. The main movement of the working element is performed from the engine, and all auxiliary movements (supply, control, setting of the mode and duration of operation) are performed manually

The most common hand-held machines in construction during the performance of sanitary, finishing, installation and repair work, as well as the installation of metal structures and technological equipment. The use of various machines allows in 5... 10 times increase labor productivity (compared to manual work), significantly reduce labor intensity and improve the quality of technological operations performed, as well as improve working conditions of the worker

Hand-held machines (PM) are classified according to the following characteristics:

by purpose - machines for the processing of metals, wood and stone, for assembly, finishing, installation, land and drilling;

by type of drive - electric, pneumatic, motorized (driven by an internal combustion engine), hydraulic and powder machines (mounting powder pistols, pyrotechnic mandrels);

according to the method of power energy conversion - electromagnetic, mechanical, compression-vacuum and spring;

in terms of performance and speed control - straight lines (axes of the working element and drive are parallel or coincident), angular (axes of the working element and drive are located at an angle), reversible and non-reversible, single-speed and multi-speed;

by the nature of the movement of the working element - machines with rotational, reciprocating and complex movement. In rotating machines, the force action of the working member on the treated object is carried out continuously

Working bodies performing reciprocating and complex movements exert force influence on the treated object with pulses

In construction, electric and pneumatic hand machines became predominant. It is more profitable to use electric manual machines in relatively small volumes, pneumatic ones in medium and large volumes at facilities serviced by a mobile compressor unit or located in a centralized compressed air network. Compared to pneumatic, electric machines have a significantly higher (4... 6 times) efficiency. Many types of hand machines (wood processing machines - disc saws, chops, choppers, rams for compacting soil, perforators, etc.) are produced only with electric drive

Currently, electric machines account for more than 60%, and pneumatic machines account for about 30% of the total production of hand machines in our country

Manual machines are assigned an index consisting of alphanumeric and numerical parts. By index, you can determine the type of drive, the group of the machine by purpose and design features. The letter part of the index of drive hand machines characterizes the type of drive: IE - electric, IE - pneumatic, IG - hydraulic and hydro-pneumatic, ID - motorized with an internal combustion engine. For nozzles, tool heads and auxiliary equipment, regardless of the type of drive, the IR index is set. The digital part of the index includes four digits, the first of which denotes the group number, and the second - the number of the subgroup of the classification table. The last two digits of the index characterize the registration number of the model, and each newly released model is assigned a higher number. The letters after the digital part of the index indicate the serial modernization of the machine and the type of its special design. All manual machines are divided into 10 groups by purpose, each of which is divided into 9 subgroups depending on the design features of each type of machine

As an example, we decipher the index of the electric manual grinding machine IE-2004B: IE - type of drive (electric), 2 - group number according to the classification table (grinding machine), 0 - subgroup number by type of design (grinding machine straight), 04 - serial registration number of the machine, B - serial modernization of the machine (second)

A unified system of indexing manual machines helps to streamline their output and facilitates the task of reasonable selection of machines

Electric manual machine is an electric, vibration and noise-proof portable unit consisting of a housing built into the housing of an electric drive, a transmission mechanism, a working tool, starting and regulating equipment

All hand-held electrical machines are divided into three classes according to the degree of operator protection against electric shock

Class 1 refers to machines with a rated current voltage above 42 V, in which at least one metal part accessible for touching is separated by those parts under voltage, only by one working functional insulation. Manual machines of class I are not used in construction and installation works

Class II includes hand-held machines operating at a low, safe voltage for humans up to 42 V, powered by an independent current source or from a common network through a current converter or transformer. Operation of grade II and III machines is possible without the use of personal protective equipment

To date, fully electrically safe manual machines have been created, equipped not only with double, but also with the so-called full electrical insulation. Such machines have an all-metal body and do not contain, in addition to the working element, external metal parts

A distinctive feature of ERM with double insulation (class II machines) is the presence in their design of two independent insulation layers, including working and additional insulation

ERM working insulation with double insulation is not fundamentally different from ERM insulation of classes I and II. Additional insulation is carried out by using parts made of polymeric materials capable of performing a protective function if the working insulation is damaged there are several schemes for performing additional insulation in ERM

By the type of drive are distinguished:

electromechanical manual machines - with a rotary engine, the movement of which is communicated to the working body (tool) through a transfer device (reduction gear, crank mechanism, etc.);

compression-vacuum machines, in which energy transfer to the working element is carried out by a striker pneumatically connected to an intermediate converter mechanism;

electromagnetic - with a linear electromagnetic motor of reciprocating (impact) action, communicating the movement to the working tool directly

Single-phase collector motors of type KN II protection with a useful power of 120... 850 W, single and three-phase asynchronous motors with short-circuited rotor with useful power 120... 750 W with power from the normal (50 Hz) and increased (200 Hz) frequencies

Machines with electric motors of the KN type have become predominantly widespread in construction due to the ease, portability, mobility and the ability to directly connect a single-phase and three-phase current of a normal frequency to the network. It is mastered the production of hand-held electric machines based on lightweight high-speed collector single-phase motors with a nominal speed of 250... 333.3 (1/s)

Recently, manual machines based on DC collector motors with a power source from small-sized batteries built into the housing or handle of the machine have been developed. In drives of manual machines with collector motors, electronic control of the rotor shaft speed is increasingly used, which allows increasing their productivity due to the optimal operating mode

Three-phase asynchronous motors with a short-circuited rotor have a simpler, more reliable design (there are no collectors and brushes) and operate at a normal frequency of 50 Hz (AN type motors) and an increased frequency of 200 Hz (AS type motors). Electric motors of the AN type, having large dimensions and mass, low specific power and efficiency, are used in manual machines with a heavy operating mode. AS type motors compared to AN engines have higher energy characteristics; they are portable, fast (rotor speed up to 300 (1/s), characterized by high power per unit mass, reliable in operation and durable. These 42 V class III protection motors are used in hand-held machines operating in hazardous conditions with respect to operator electric shock

Manual machines with three-phase asynchronous motors are connected to the AC network of normal frequency (50 Hz) voltage 220/380 V through intermediate units: with motors of the AN type - through a step-down transformer, with motors of the AP type - through a frequency converter, which also performs the functions of a step-down transformer

Machines with AS type motors requiring the use of a frequency converter are most effectively used in stationary conditions at stable workplaces

In the production of electric hand machines, wide unification of units and parts is used, which can be easily replaced in case of failure

Machines with rotational movement of the working member are widespread in installation and assembly works: drilling, threaded, flaring, screw-holes, nut-screws, grinding

In this course work, a manual mechanized tool was calculated - an electric pipe. As a prototype, the Interskol electric pipe R-82 TS-01 was chosen. Electric tubing is designed to line wood of different species along and across fibers in the manufacture of elements of wooden structures

The main calculations were made:

- performance calculation;

- calculation of impact energy

Methods for ensuring safety when working with an electric pipe were also presented.

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