a - external; b - internal
Figure 4.7 - Image of the thread
The external thread is represented by solid thick main lines along the outer diameter d and solid thin lines along the inner diameter D 1. On a plane parallel to the axis of the thread, a continuous thin line is drawn over the entire length of its full profile, including the chamfer (Figure 4.7, a).
The line defining the thread boundary is indicated at the end of its full profile by a solid thick main line if the thread is visible, or by a dashed line if it is invisible (Figure 4.8, a).
Figure 4.8
The runaway thread, if necessary, is depicted as a solid thin line extending beyond its borders (Figure 4.8, b, c).
The internal thread in the sections is shown by solid thick main lines along the inner diameter D 1 and solid thin lines along the outer diameter d(Figure 4.7, b). On a plane perpendicular to the axis of the thread, a continuous thin line is drawn in the form of an arc equal to ¾ of a circle. Moreover, the beginning and end of the arc should not coincide with the center lines.
Hatching in sections and sections of threaded products is applied to a solid main line, i.e. to the line of the outer diameter of the thread on the rod and the line of the inner diameter of the thread in the hole. In threaded connections, the thread is conditionally drawn on the rod, and only the part that is not covered by the thread of the rod is shown in the hole (Figure 4.9).
Figure 4.9 - Hatching threaded joints
For operational purposes, threads are divided into fastening (metric), fastening and sealing (pipe, conical), running (trapezoidal, persistent) and special. Below are the rules for designating some general purpose threads.
Metric thread. The legend (figure 4.10) of metric threads includes: letter M (metric thread symbol), nominal (outer thread diameter (mm), through the multiplication sign (×) the step size (if small) and direction (if it is left - LH). Examples: M12, M12 × 1.5, M12 LH, M12 × 1.5 LH.
Figure 4.10 - Metric thread designation
Pipe thread. The symbol for a cylindrical pipe thread (Figure 4.11) consists of a letter G with the conditional size - the inner diameter of the pipe in inches (does not correspond to the actual outer diameter of the thread) and the accuracy class of the average diameter ( A - increased IN - normal). Examples: G1 / 2 - A, G1 / 2 LH - B.
Figure 4.11– Designation of a cylindrical pipe thread
Trapezoidal thread. The symbol (figure 4.12) of the trapezoidal thread (single start, multiple start) consists of letters Tr, outer diameter and pitch or stroke and pitch, respectively. Examples: Tr 40 × 6, Tr 40 × 6 LH, Tr 20 × 8 (P4).
Figure 4.12– Designation of a trapezoidal thread
test questions
1. What is a helix?
2. What is the difference between the right helix and the left?
3. What is a thread and how is it formed?
4. What are the main parameters and elements of the thread?
5. What is a thread runaway and how is it formed?
6. What is the purpose of the chamfer on the shaft and in the hole?
7. What is the purpose of the grooves on the rod and in the hole?
8. How do the threads on the rod and in the hole conditionally be depicted?
Parts Connections
The connection of the individual parts of the product or assembly unit with each other can be movable or motionless. With a movable connection during the operation of the machine, relative movement of parts is possible, but with a motionless one it is impossible.
Depending on the technological and operational requirements, there are connections one-piece and detachable. One-piececonnections cannot be dismantled without damage to the parts to be connected. These include:
Welded joints;
Rivet joints;
· Connections by soldering, gluing;
· Interference fit (prior to assembly, the shaft size is larger than the hole size and immobility is ensured by elastoplastic deformation of the parts).
Detachableconnections can be repeatedly assembled and disassembled without damage to the parts to be connected. These include threaded, key, slotted, pin connections.
Threaded connections
A threaded connection is understood to be a detachable connection made using threaded fasteners - screws, bolts, studs, nuts or threads applied directly to the parts to be joined. There are fixed and movable threaded connections. In fixed threaded joints made using fastening threads, the parts to be joined remain stationary relative to each other during operation. These include bolted, hairpin and screw connections.
Bolted connection. Bolt connection, consisting of a bolt, nut, washer and parts to be connected, is as follows. In the connected parts 1 and 2, through holes are drilled with a diameter d 0 \u003d (1.05 ... 1.10) dwhere d- diameter of the thread of the bolt. A bolt 3 is inserted into these holes, a washer 4 is put on it, and a nut 5 is screwed on (Figure 5.1).
A bolted joint drawing is developed based on a given thread diameter and thickness H 1 and H 2 connected parts. The length of the bolt
l \u003d H 1 + H 2 + S W + H + K,or l ≈ H 1 + H 2 + 1.3 d,
where S w \u003d 0.15 d - thickness of the washer;
H \u003d 0.8d - nut height;
K \u003d 0.35 d- the length of the protruding rod of the bolt.
Figure 5.1 Figure 5.2
The estimated bolt length is rounded to the nearest standard value. Cut length
l 0 ≥ l - (H 1 + H 2) - 5
also defined in accordance with the standard. In the drawing of a bolted connection, at least two images are performed (Figure 5.2). When depicting a bolted connection in section, standard parts (bolt, nut, washer) are shown uncut. The head of the bolt and nut in the main view is usually represented by three faces.
Figure 5.3
Three dimensions are indicated in the drawing: thread diameter, bolt length and bolt hole diameter in the parts to be joined.
With a simplified image of a bolted connection, the dimensions of the elements of the fasteners are determined by conditional ratios depending on the diameter of the thread of the bolt d(figure 5.3) . In this case, the threads are conventionally shown along the entire length of the bolt rod, and the chamfers on the fasteners and the gap between the hole and the bolt rod are not shown.
Hairpin connection. A threaded joint consists of a stud, nut, washer and connected parts. It is used when one of the parts to be joined has a significant thickness, when it is impractical to drill a through hole for a bolt of large length.
A hairpin connection is performed as follows. In part 1, a nest is drilled with a diameter D 1 and cut the thread. Threaded hole dimensions D depend on the diameter, pitch and thread length of the screwed end of the stud and are selected taking into account the thread margin h and its undercut a. The stock of threads with a guarantee ensures that the stud 2 is screwed into the socket for the entire length of its threaded end l 1. In part 3, a hole is drilled with a diameter (1.05 ... 1.10) d and put it on a hairpin. Then, the washer 4 is put on the stud and the nut 5 is screwed on (Figure 5.4).
Threaded end length l 1the studs depend on the material of the part into which it is screwed. Hairpin length
l \u003d H 2 + S W + H + K or l \u003d H 2 + 1,3d,
where H 2
S w- thickness of the washer;
H \u003d 0.8d - nut height;
K \u003d 0.35 d- the length of the protruding end of the stud over the nut.
Figure 5.4
The design length of the stud is rounded to the standard value.
In the drawing of the hairpin connection (Figure 5.5), the dividing line of the parts to be joined must coincide with the thread boundary of the screwed end of the hairpin. The drawing indicates three sizes: the diameter of the thread, the length of the stud and the diameter of the hole in the joining part.
Figure 5.5 Figure 5.6
In a simplified image of a stud connection (Figure 5.6), the threads are conventionally shown along the entire length of the stud. The dimensions of the fasteners depend on the diameter of the stud thread. d.
Screw connection. The screw connection consists of a screw with a washer and connected parts. It is used for fastening parts experiencing light loads.
Screw connection as follows. In part 1, a socket is drilled, in which a thread is then cut. In the joined part 2, a through hole with a diameter of (1.05 ... 1.10) d. If a screw with a countersunk or semi-countersunk head is used, the corresponding side of the part must have a 90 0 countersink beneath it. The screw 3 should freely enter the hole of part 2 and screw into part 1 (Figure 5.7).
Screw length ldetermined depending on the shape of the head, for example, the length of a screw with a cylindrical head (Figure 4.20)
l \u003d H + S w + l 1,
where H - thickness of the attached part;
S w- thickness of the washer;
l 1- the length of the screwed threaded end of the screw, depending on the material
Figure 5.7
The estimated screw length is rounded to the standard value. In a screw connection, the dividing line of the parts to be joined should be about three steps of the thread below the screw thread boundary. If the diameter of the screw head is less than 12 mm, then the slot is recommended to be depicted with one thickened line. In the top view of the screw connection, the slot is shown rotated by 45 0.
Figure 5.8 Figure 5.9
In the drawing of the screw connection, three sizes are applied: thread diameter, screw length and hole diameter of the part to be attached (Figure 5.8). With a simplified image of a screw connection, the threads are conventionally shown along the entire length of the screw shaft; the end of the threaded hole, including the margin and undercut of the thread, as well as the gap between the hole and the attached part and the screw, are not shown (Figure 5.9).
test questions
1. What parts does the bolt connection consist of?
2. What are the details of the stud connection?
3. What are the parts of the screw connection?
Welded joints
Welding is the process of obtaining an indivisible connection by establishing interatomic bonds between the parts to be welded when they are local or general heating, or plastic deformation, or the combined action of both(GOST 2601-84 *).
Welded joints occupy one of the leading places in modern technology. Welding is the most common type of one-piece joints, as it brings components closer to integral parts better than others, replacing parts obtained by casting, forging, stamping, etc.
The most widely used are welding joints of homogeneous and dissimilar metals, as well as metallographic and plastic masses. The use of welded joints allows to reduce the metal consumption of production to 40% and significantly reduce the complexity of technological processes.
disadvantageswelded joints are caused by the occurrence of thermal deformations, limited weldability of parts from refractory materials, the dependence of the quality of the weld on the qualifications of the welder.
Classification of types of welding.Depending on the processes (physical, technical and technological) that occur in the process during welding, distinguish fusion weldingand pressure welding(Figure 5.10).
Physical signs for welding classification are:
· The form of energy used to form a welded joint (determines the class of welding);
· Type of energy source (determines the type of welding).
Technical features in the classification of welding are:
· A method of protecting metal in the welding zone (welding in air, vacuum, etc.);
· Process continuity (continuous, intermittent welding);
· Degree of mechanization (manual, automated welding, etc.).
Technological features used to classify welding of each type, for example for arc welding - this is the type of electrode (melting, metal, etc.), the type of arc (free, compressed), the use of filler material, etc.
The most common were gas, arc and contact welding.
At gaswelding the edges of the connected parts are heated in a flame of gases (acetylene, air, etc.), burned in a stream of oxygen at the outlet of the burner. The filler material (in the form of a metal rod) and partially the material of the parts to be welded melt under the influence of temperature and fill the gap between them. The weld metal hardens to form a seam welded joint.
Figure 5.10
At arcwelding the edges of the welded parts are heated electric arcarising between them and the electrode. A weld is formed as a result of melting of the electrode itself.
At contactwelding is carried out as a result of external compressive force and local heating of the parts due to the heat generated when an electric current passes through their connected parts.
Classification of seams.The technology for making welds is different. It depends on the form of processing the edges of the parts to be welded, their relative position and the conditions in which the bar and the connected parts are melted. In the welding industry, as a rule, standard welds are used, which are formed with certain welding methods (table 5.1).
Table 5.1 - Designation of standardized welding methods
Depending on the relative position of the parts to be welded, they distinguish:
· buttconnection (C) - the parts to be welded are connected along their end surfaces (Figure 5.11, a);
· angularconnection (U) - the parts to be welded are located at an angle and are connected along the edges (Figure 5.11, b);
· t-shapedconnection (T) - the end face of one part is connected to the side surface of another (Figure 5.11, c);
· lapconnection (N) - the side surfaces of the parts to be joined partially overlap each other (Figure 5.11, d).
Figure 5.11
Welds are divided by position in space, length, external shape, number of passes, form of preparation of the edges, the nature of the execution.
By position in space (GOST 11969-79 *) welding seams (Figure 5.12) are divided into lower 1, vertical 2, horizontal 3, semi-ceiling and ceiling 4.
Figure 5.12 Figure 5.13
In length distinguish seams (figure 5.13) continuous(no gaps) and intermittent(with breaks). Intermittent seam is characterized by the length of the welded sections llocated at a certain step t.
In appearance welds are divided into convex (figure 5.14, a), flat (figure 5.14, b) and concave (figure 5.14, c). In figure 5.14 are indicated: a - thickness fillet weld; q - gain height; TO - the height of the seam leg.
By the number of passes Distinguish single-pass and multi-pass welding seams.
By nature of execution Distinguish seams unilateral and bilateral.
Figure 5.14
Image of welds.On the image of the weld, the front and back sides are distinguished (Figure 5.15). The front side of a unilateral seam is the side from which welding is performed (see Figure 5.15, a); a bilateral seam with an asymmetrical bevel is the side from which the main seam is welded (see Figure 5.15, b); a double-sided seam with a symmetrical bevel - either side (see figure 5.15, c).
Figure 5.15
Visible welds in the drawing depict the main line, invisible - dashed (Figure 5.16). Visible single welding points, regardless of the welding method, are conventionally depicted by the “+” sign, which is performed by the main line with a length of 5 ... 10 mm (Figure 5.17). Invisible single weld points are not shown in the drawing.
Figure 5.16
Availability weld on the image parts are indicated with a one-way arrow (Figure 5.18). The symbol of the front seam is written above the shelf of the leader line, and the reverse - under the shelf of the leader line (Figure 5.19).
Figure 5.17 Figure 5.18
Figure 5.19
Designation of welds.The structure of the designation of standard seams, determined by GOST 2.312-72 *, is shown in Figure 5.20, where:
· 1 - auxiliary signs (О - seam in a closed line; ┐ - mounting seam);
· 2 - standard number;
· 3 - standard alphanumeric designation seam;
· 4 - standard symbol for the method of performing this seam;
· 5 - conventional graphic sign of the seam and the size of its leg;
· 6 - the size of the weld, mm (for an intermittent weld - the length of the welded section, the “/” or “Z” sign and step; for a single welding spot — the calculated diameter of the point; for a contact welding electric arc — the calculated diameter of the point, the “/” sign or “Z” and a step; for a contact roller weld, the calculated weld size; for an intermittent contact roller weld, the calculated weld width, the multiplication sign, the length of the weld section, the “/” or “Z” sign and the step);
· 7 - auxiliary characters from table 5.2;
· 8 - designation of the surface roughness of the seam;
· 9 - an indication of the control of the seam.
Figure 5.20
Table 5.2 - Auxiliary signs in the designation of the seam
| Sign | Sign Meaning | Location of character relative to leader line shelf | |
| on the front side | on the back side | ||
| Reinforce the seam | |||
| Process sag and bumps in the weld with a smooth transition to the base metal | |||
| The seam must be made during the installation of the product, i.e. when installed according to the installation drawing at the place of use | |||
| The seam is intermittent or spot with a chain arrangement (line angle 60 0) | |||
| Intermittent or spot stitch | |||
| Seam in a closed line (sign diameter 3 ... 5 mm) | |||
| A seam along an open line (used if the location of the seam is clear from the drawing) |
Threaded connections belong to the largest group of detachable connections. In this way, you can screw up the parts or connect them into one whole, using special fasteners - bolts, screws, nuts, studs, etc. The designation of the pipe thread in the drawings allows you to understand how the part looks in real life.
Types of threaded connections
Depending on the purpose of the thread, they are divided into three types:
- Fixing. When connecting and screwing up several parts in this case, fasteners are used.
- Fixing and sealing. To tightly connect the parts, they use special transitional parts called fittings or couplings.
- Chassis. They are used when it is necessary to convert rotational motion to translational (in a jack, manual and blacksmith press, etc.) or, conversely, translational to rotational (in automatic screwdrivers).
On a note! A thread is a surface that is formed by the helical movement of a flat contour along a conical or cylindrical surface.
Work surface options
The characteristic parameters of the thread include the following:
- Outer diameter (d) - measured by the protrusions on the profile rod or by the depressions in the holes.
- Inner diameter (d1) - measured by the depressions on the profile rod or by the protrusions in the holes.
- Profile - designation of the cross-section of a pipe thread in a plane that passes through the axis.
- Step (p) is the distance at which two adjacent turns are located. It is defined between the same sides - right or left.
- The side of the profile is a rectilinear portion of the helical surface.
The image of the thread in the drawings
Chopped on a rod
The outer diameter, fermented in front and on the left, is applied by a solid main line, and the inner one by a solid thin line. The chamfer is not shown in the left view. Due to this, you can draw the inner diameter of the thread with a solid thin line, which is open one fourth of the diameter of the circle.
Note! One end of the arc is not brought to the center line by approximately 2 mm, but the other end has crossed the second center line at the same distance.
The boundary where the sliced \u200b\u200bportion ends is shown by a solid main line.
Made inside the cylinder
In the front view, the inner and outer diameter of the thread made in the hole is shown by a dashed dashed line.
In the left view, the chamfer is not shown, and the outer diameter is depicted by a thin solid line, which is open for a quarter of a circle. The arc in one case is not brought to the center line, but in the other it intersects it by the same amount. The inner diameter is drawn by a solid main line. The thread boundary is indicated by a dashed line.
As indicated in the drawing pipe thread, we learn the following example.
Metric Tube Designation
In the drawings, metric threads are designated with the letter M. Then the value of the outer diameter (for example, M20), as well as the pitch of the fine thread (M20x1.5) are indicated. If the last parameter is not specified, this means that the part has a large step. The step size is selected according to GOST.
GOST 24705 - 81
Thread sizes
Metric thread, with a range of diameters from 1 to 600 mm, has found wide application in industry and household appliances. The thread pitch is measured in millimeters and has a spread of its digital values \u200b\u200bfrom 0.25 to 6 mm.
The profile of the metric thread is a geometric equilateral triangle with an angle at the apex of 60 °. The profile height of the metric thread is calculated by the formula H \u003d 0.866025404 × P, where H is the height and P is the thread pitch.
| d CP \u003d M - 2 | H \u003d M - 0.649519053 × P |
| d BH \u003d M - 2 | H \u003d M - 1.082531755 × P |
| d B \u003d M - 2 | H \u003d M - 1.226869322 × P |
Metric cylindrical thread is widely used in the manufacture of complex technical threaded connections in instrumentation, engineering, as well as in the mass production of fasteners such as screws, bolts, studs, nuts, etc.
Designated metric thread the letter M:
- M16, M42, M64 - with a large step
- M16 × 0.5; M42 × 2; M64 × 3 - with a small step
- M42 × 3 (P1) - this means that the thread is multi-thread with a diameter of 42 mm, a pitch of 1 mm and its stroke is 3 mm ( three-way)
- M14LH, M40 × 2LH, M42 × 3 (P1) LH - if you need to mark the left thread, then after the symbol mark the letters LH
Modern engineering cannot be imagined without carvings. Thread is the main element in all threaded connections. The main positive qualities of threaded joints are relative ease of manufacture, ease of use, ability to withstand high loads, versatility and reliability. All threaded connections according to the purpose and nature of use are divided into movable (kinematic) and fixed.
Thread pitch selectionPitch is one of the main characteristics of any thread, and it can be both small and large.
In those joints that are subject to high loads (including impact nature), threads with large pitch are used.
To obtain a tight joint or to interconnect thin-walled parts, fine-pitch threads are used. In addition, they are often used in various installation and adjustment screws and nuts to achieve the most accurate settings.
Thread cuttingBoth external and internal threads on screw-cutting lathes are cut using tools such as threaded cutters and combs. Since threading with cutters has a relatively low productivity, this method is now mainly used for the manufacture of piece or small-batch parts, as well as in the process of manufacturing lead screws, precision screws and calibers.
This method of manufacturing threads is used in large-scale production of parts on specialized thread rolling equipment. It is characterized by high performance and relatively low cost. This method is based on plastic deformation of the surface of metals, and therefore it does not involve chip removal.
Thread millingBoth external and internal threads can be cut by milling, and special thread milling machines are used for this. As cutting tools, they use comb cutters that cut into the body of the part with a radial feed, as a result of which a thread appears on the surface.
Precision thread grindingExact threads that are present, for example, on various calibers, threaded rollers, etc. are made most often using a method such as grinding. Specialized equipment is also used for this.
The concept of tolerances of threaded connectionsWhen threads are made, their actual profiles have some deviations from theoretical ones. Therefore, in order to guarantee the coupling of threaded parts, as well as to achieve their interchangeability, these deviations are regulated by tolerances.
The average diameter of the thread is the main indicator that characterizes the threaded connection. The most widely used fit for threaded connections is sliding, when this indicator is equal to the smallest average diameter of the thread of the nut and the largest average diameter of the thread of the bolt.
GOST 2.311-68
T52 group
INTERSTATE STANDARD
Unified design documentation system
THREAD PICTURE
Unified system for design documentation. Image of screw
ISS 01.100.20
Date introduced 1971-01-01
INFORMATION DATA
1. DEVELOPED AND INTRODUCED by the Committee of Standards, Measures and Measuring Instruments under the Council of Ministers of the USSR
2. APPROVED AND IMPLEMENTED BY Decree of the Committee of Standards, Measures and Measuring Instruments under the Council of Ministers of the USSR of May 28, 1968 N 755
3. The standard complies with ST SEV 284-76
4. REPLACEMENT of GOST 3459-59
5. EDITION (August 2007) with Amendment No. 1, approved in April 1987 (IMS 7-87)
1. This standard establishes the rules for the image and marking of threads on the drawings of all industries and construction.
The standard complies with ST SEV 284-76.
2. Thread depict:
a) on the rod - solid main lines along the outer diameter of the thread and solid thin lines - along the inner diameter.
In the images obtained by projecting onto a plane parallel to the axis of the rod, a solid thin line along the inner diameter of the thread is drawn along the entire length of the thread without run-off, and in views obtained by projecting onto a plane perpendicular to the axis of the rod, an arc is approximately drawn along the internal diameter of the thread, approximately equal to a circle open in any place (Fig. 1, 2);
Damn. 1
Damn. 2
b) in the hole - solid main lines along the inner diameter of the thread and solid thin lines - along the outer diameter.
On cuts parallel to the axis of the hole, a solid thin line along the outer diameter of the thread is drawn along the entire length of the thread without running, and on images obtained by projecting onto a plane perpendicular to the axis of the hole, an arc approximately equal to a circle open in any location (Fig. 3, 4).
Damn. 3
Damn. 4
The solid thin line in the image of the thread is applied at a distance of not less than 0.8 mm from the main line and not more than the size of the thread pitch.
3. Threads shown as invisible are depicted by dashed lines of the same thickness along the outer and inner diameters (Fig. 5).
Damn. 5
4. The line that defines the thread boundary is applied on the rod and in the threaded hole at the end of the full thread profile (before the start of the run). The thread boundary is drawn up to the line of the outer diameter of the thread and is shown as a solid main or dashed line if the thread is depicted as invisible (Fig. 6-8).
Damn. 7
Damn. 8
5. Hatching in sections and sections is carried out to the line of the outer diameter of the thread on the rods and to the line of the inner diameter in the hole, ie in both cases to a solid main line (see Fig. 3, 4, 7, 8).
6. The size of the length of the thread with a full profile (without runoff) on the rod and in the hole is indicated as shown in Fig. 9 a and 10 a.
The size of the length of the thread (with run) indicate, as shown in Fig. 9 b and 10 b.
If necessary, indicate the magnitude of the run on the rod dimensions are applied, as shown in Fig. 9 in.
The thread run is represented by a solid thin straight line, as shown in Fig. 9. b, in and 10 b.
Damn. 9
Damn. 10
Undercut thread, made to stop, depict, as shown in Fig. 11 a and in.
It is allowed to depict undercutting of the thread, as shown in Fig. 11 b and g.
7. The main plane of the tapered thread on the shaft, if necessary, indicate a thin solid line, as shown in Fig. 12.
Damn. 12
8. In the drawings, according to which the thread is not performed, the end of the blind threaded hole may be depicted as shown in Figs. 13 and 14, even if there is a difference between the depth of the hole for the thread and the length of the thread.
Damn. 13
Damn. 14
9. Chamfers on a threaded rod and in a threaded hole that do not have a special designation are not shown in the projection onto a plane perpendicular to the axis of the rod or hole (Fig. 15-17). A solid thin line of the image of the thread on the rod should intersect the line of the chamfer border (see Figure 15).
Damn. 15
Damn. 16
Damn. 17
10. Threads with a non-standard profile are shown in one of the ways shown in Fig. 18, with all the necessary dimensions and maximum deviations. In addition to the dimensions and maximum deviations of the thread, the drawing indicates additional data on the number of approaches, on the left direction of the thread, etc. with the addition of the word "Thread".
11. On cuts threaded connection in the image on a plane parallel to its axis, only the part of the thread that is not covered by the thread of the rod is shown in the hole (Fig. 19, 20).
Damn. 19
Damn. 20
12. The designations of the threads indicate, according to the relevant standards, the dimensions and maximum deviations of the threads and assign them for all threads except tapered and cylindrical to the outer diameter, as shown in Fig. 21, 22.
Damn. 21
Damn. 22
The designations of tapered threads and cylindrical pipe threads are applied as shown in Fig. 23.
Heck. 23
Note. Sign "*" marks the place of application of the thread symbol.
13. Special threads with a standard profile are abbreviated Cn and the thread designation.
(Amended edition, Amendment No. 1).
Electronic text of the document
prepared by Codex JSC and verified against:
official publication
Unified system of design documentation:
Sat GOSTs. - M .: Standartinform, 2007
