Simplified and conventional images of fasteners. Symbols of standard fasteners Designation of bolts on GOST drawings
Metric thread (GOST 9150-2002)
Example of a symbol:
M 20×1.5 – metric cylindrical thread with a rod diameter of 20 mm and a thread pitch of 1.5 mm;
M 20× Ph 3R 1.5 - metric cylindrical thread with a rod diameter of 20 mm, two-start with a thread pitch of 1.5 mm;
M 20×1.5- L.H.– metric cylindrical thread with a rod diameter of 20 mm and a thread pitch of 1.5 mm, left;
MK 20×1.5 – metric conical thread with a rod diameter of 20 mm and a thread pitch of 1.5 mm;
Inch thread
Example of a symbol:
1′ – inch cylindrical thread with a rod diameter of 25.4 mm;
⅜′ – inch cylindrical thread with a rod diameter of 9.5 mm (⅜′);
1' L.H.– inch cylindrical thread with a rod diameter of 25.4 mm, left;
TO 1′ – inch conical thread with a rod diameter of 25.4 mm;
Cylindrical pipe thread (GOST 6357-81)
Example of a symbol:
G 1 – cylindrical pipe thread with a nominal diameter of 1′;
G ⅜ L.H.– cylindrical pipe thread (⅜′) left;
Conical pipe thread (GOST 6211-81)
Example of a symbol:
R 1½ – external conical pipe thread;
Rc 1½ – internal conical pipe thread;
Trapezoidal thread (GOST 9484-81)
Example of a symbol:
Tr 36×6 – trapezoidal thread with a rod diameter of 36 mm and a pitch of 6 mm;
Tr 36×12( R 6) – trapezoidal thread with a rod diameter of 36 mm, two-start, pitch 6 mm;
Tr 36×6 L.H.– trapezoidal thread with a rod diameter of 36 mm and a pitch of 6 mm, left;
Persistent thread (GOST 10177-82)
Example of a symbol:
S 36×5 – persistent thread with a rod diameter of 36 mm and a pitch of 5 mm;
S 36×5 L.H.– persistent thread T with a rod diameter of 36 mm and a pitch of 5 mm, left;
Rectangular thread (non-standard)
Rectangular thread (Fig. 85) is non-standard, which means it does not have a symbol. Therefore, the drawing must indicate all the dimensions necessary for its manufacture.
Rice. 85 Rectangular thread
In a threaded connection, one part has an external thread and the other has an internal thread. External thread in a connection it is a male surface, and the part that has it is called a “bolt” (screw, stud). Internal thread is a covering surface and is called a “nut” (socket, etc.).
In the drawings, the thread is shown conventionally: a solid main line shows the tops of the turns, and a solid thin line shows the troughs of the turns (Fig. 86).
Rice. 86 Image of thread in the drawings: A– external; b- internal
On sections of a threaded connection in the image on a plane parallel to its axis, only that part of the thread that is not covered by the thread of the rod is shown in the hole (Fig. 87).
Rice. 87 Illustration of thread in connection
The correct application of the thread designation on the drawings is given in table. 2.
Fasteners
Fasteners include bolts, screws, studs, nuts, washers, cotter pins.
The shape, dimensions and other characteristics of fasteners (such as material, strength class, type of coating, etc.) are standardized, but without special knowledge they cannot be reasonably assigned. Therefore, in the “Engineering Graphics” course, some parameters are not indicated in the symbols of fasteners. Most fastener threaded products are manufactured with metric threads, large or fine pitch. Drawings of fasteners are made according to actual dimensions, which are established by the relevant standard.
Bolts
A bolt is a cylindrical rod, at one end of which there is a head (hexagonal, square, round or special), and at the other end there is a thread for screwing on a nut.
table 2
| Thread type | Symbol of thread | Designation of threads on images in a plane parallel to the thread axis | Designation of threads on images in a plane perpendicular to the thread axis | ||
| on the rod | in the hole | on the rod | in the hole | ||
| Metric thread | M |  |  |  |  |
| Trapezoid thread - long single start | Tr |  |  |  |  |
| Thread persistent | S |  |  |  |  |
| Cylindrical pipe thread | G |  |  |  |  |
| Conical pipe thread: external internal | R Rc |  |  |  |  |
Rice. 88 Bolts
An example of a complete symbol for a high-precision bolt with thread diameter d= 16 mm long l= 60 mm, strength class 5.8, version 2, fine pitch R=1.5 mm, with tolerance range 69, uncoated:
Bolt 2M16´1.5.6g´60.58 GOST 7798-70.
Bolt designation on training drawings:
Bolt 2M16´1.5´60 GOST 7798-70.
Hairpins
Hairpin is called a cylindrical rod, at both ends of which there is a metric thread (Fig. 89). Studs are used to connect parts when there is no space to place a bolt head or nut, and also when one of the parts being connected is of significant thickness, which makes it uneconomical to install a long bolt.
Threaded end of stud l 1, screwed into the part, is called a landing. Its length depends on the strength and ductility of the material from which the part is made.
For durable and ductile materials (steel, bronze, brass, etc.)
l 1 = d(GOST 22032-76, GOST 22033-76).
For gray and ductile cast iron:
l 1 = 1,25d(GOST 22034-76, GOST 22035-76),
l 1 = 1,6d(GOST 22036-76, GOST 22037-76).
For parts made of light alloys:
l 1 = 2d(GOST 22038-76, GOST 22039-76),
l 1 = 2,5d(GOST 22040-76, GOST 22041-76).
On the other threaded end of the stud l 0 the nut is screwed on. Stud length l conventionally consider the length of its rod without the length of the landing end l 1 (see Fig. 89).
An example of a symbol for a stud with thread diameter d= 20 mm, in increments P= 1.5 mm, with tolerance range 6 g, length l= 100 mm, with screw-in threaded end length l 1 =d, normal accuracy, strength class 5.8, uncoated:
Hairpin M20´1.5-6g´100.58 GOST 22032-76.
Designation of the same stud on training drawings:
Hairpin M20´1.5´100 GOST 22032-76.
Screws
A screw is a cylindrical rod with a head at one end and a metric thread at the other. Screws most often have a slot in the head for a screwdriver, but there are screws with hexagonal and square heads for a wrench.
Depending on their purpose, screws are divided into fastening, setting, adjusting, etc. Set screws are used to adjust gaps and fix parts during assembly. The most common type in mechanical engineering are fastening screws for metal. Depending on the operating conditions, these screws are made with a cylindrical shape, GOST 1491-80 (Fig. 90, A), semicircular, GOST 17473-80 (Fig. 90, b), semi-secret, GOST 17474-80 (Fig. 90, V) and secret, GOST 17475-80 (Fig. 90, G) heads. The determining dimensions for all screws are the thread diameter d and length l. For length l Most machine screws accept the length of their shank (excluding head).
For countersunk head screws, size l includes shaft length and head height (see Fig. 90, G).
Screw A M8´1-6g´50.48 GOST 17473-80.
The same on the training drawings:
Screw M8´1´50 GOST 17473-80.
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| A | b |
 |  |
| V | G |
| Rice. 90 Screws |
Nuts
A nut is a part that has a threaded hole for screwing onto a bolt or stud with the same thread. Standard nuts can be hexagonal (Fig. 91, A), slotted and crowned (Fig. 91, b), round (Fig. 91, V), lamb (Fig. 91, G) and etc.
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| A | b | V | G |
| Rice. 91 Nuts |
Hex nuts are divided into normal, low, high and extra high heights.
Nuts are manufactured with normal and high precision. Some hex nuts are manufactured in two versions (Fig. 92): version 1 - with two chamfers; version 2 – with one chamfer.
An example of a symbol for a hex nut (normal accuracy), version 1 (with two chamfers), thread diameter d= 30 mm, fine pitch P = 2 mm , with tolerance range 7 N, strength class 5, uncoated:
Nut M30´2.5 GOST 5915-70.
The same on the training drawings:
Rice. 92 Nut versions
Washers
A washer is a stamped or turned ring that is placed under nuts or heads of bolts and screws.
Round washers (GOST 11371-78) have 2 designs (Fig. 93): version 1 – without chamfer; version 2 – with chamfer.
An example of a symbol for a normal washer, version 2, for a fastener with a thread diameter of 30 mm, set thickness, made of material group 01, with coating 01, thickness 9 microns:
Washer 2.30.01.019 GOST 11371-78.
The same on the training drawings:
Washer 2.30 GOST 11371-78.
Rice. 93 Washer designs
The studs are clean.
A stud is a cylindrical rod, at one end of which there is a thread for screwing the stud into the body of the part, and at the other end there is a thread for screwing a nut. Clean studs are made from clean-drawn calibrated metal with metric threads. Inch threaded studs can only be used as replacement parts and should not be used when designing new products. By type, studs are divided into two types: without a groove, conventionally designated by the letter A, and with a groove, designated by the letter B.
Depending on the depth of screwing of the stud into the body, the parts are distinguished: studs of the type I with a screw depth equal to 1.35 times the diameter and stud type II with a screwing depth equal to 1 diameter.
Depending on the length of the cut part for the nut, the studs are conventionally designated: for an ordinary nut with the letter O, for a castle nut or an ordinary one with a cotter pin - K. Clean studs are made from machine-cut steel according to GOST 1414-54, as well as from steel according to GOST: 1050-60, 4543-61
And 535-58
. In table No. 12 and table No. 13 and on (Fig. 448) The main dimensions of the studs are given.
Hairpin M10 X 60A10 OST 20001-38 - stud with main metric thread diameter 10 mm, length t = 60 mm, without groove, with a screwing depth of 1.35 d for an ordinary nut. Hairpin 3/8" X 60B11K OST 20001-38 - stud with inch thread with a diameter of 3/8 ", length t - 60 mm, with a groove and a screwing depth of 1b for a castle nut.
Bolts.
A bolt is a cylindrical rod, at one end of which there is a head, and at the other there is a thread made by knurling or cutting. The bolt head can be hexagonal (449, a), spherical (449, b) or conical (449, c).
The hex head (the most common) is a hexagonal regular prism with one chamfer, removed by turning the head along a conical surface at an angle 30° to the plane of the head in order to protect the corners from damage. According to the degree of manufacturing accuracy, bolts are divided into bolts of normal accuracy and increased accuracy. Table 14 and (Fig. 450) show the main dimensions of high-precision hex head bolts.
Examples of symbols: Bolt M10 X 50 GOST 7805-62- bolt with metric thread with coarse pitch, diameter 10 mm, length 50 mm, 3rd accuracy class (version I (Accuracy class 3 and version I are not indicated in the designation.)). Bolt II M12 X 1.25 X 75 cl. 2 GOST 7805-62 - bolt with metric thread with fine pitch (1.25 mm), diameter 12 mm, length 75 mm, 2nd accuracy class (version II).
Screws.
A screw is a rod with a head and threads. Screws are used to connect parts. Screws made by cutting are called turned, while screws made by stamping and with rolled threads are called knurled. The shape of the screw head depends on its purpose. There are screws with a screwdriver head (451, a) and a key head (451, b).
Table 15 shows several types of screws indicating the main dimensions.
Examples of symbols: Screw M12 X 30 cl. 2 GOST 1491-62 ; Screw M12 X 28 GOST 1476-58; Screw M8 X 30 GOST 1482-58.
Nuts.
The nuts are regular hexagonal prisms with a cut hole (Fig. 452), in which conical chamfers are removed from one or two bases.
If a hex nut has a groove for a cotter pin, the nut is called a slotted nut. A hex nut that has a cylindrical protrusion with grooves for cotter pins is called a castle nut. Nuts, depending on the nature of surface treatment, are of normal and increased accuracy. In addition to hexagonal ones, round nuts with slots for a key (453, a) are produced, as well as shaped wing nuts for tightening without a key (453, b).
Bolts, screws and nuts are made from the following grades of steel: Art. 3, Art. 4 and Art. 5 - according to GOST 380-60; steel 10, 15, 20, 25, 30 and 35 - according to GOST 1050-60; 35Х, 40Х and 45Х - according to GOST 4543-61; automatic steel A12, A20 and A30 - according to GOST 1414-54. In table 16 and on figure 454 The dimensions of high-precision hex nuts are given.
Example of a symbol: Nuts M16 class. 2 GOST 5927-62.
Washers.
Washers are used to protect the surface of parts from damage and to prevent self-unscrewing of bolts, screws and nuts. The most widely used washers are clean and black. Clean washers are called turned ones, black washers are called stamped ones.
Washers are made from the following grades of steel: Art. 0, St. 1, Art. 2, Art. 3 and Art. 4 - by GOST 380-60; Steel 08, 10, 15, 20, 25, 30, 35 and 40 - each GOST 1050-60; A12 - by GOST 1414-54. In cases where drawings of clean and black washers are made, according to which these washers will not be manufactured, you can draw them in relative sizes depending on the given outer diameter of the thread d 0 (Fig. 455).
| d | D | s | c |
| d 0 +1÷3mm | 2.2d 0 | 0.15d 0 | 0.25S |
Examples of symbols: Washer 20 GOST 6957-54; Washer 20 GOST 6959-54.
Adjustable cotter pins.
An adjustable cotter pin is a double rod bent from a piece of wire of a special section, which serves to hold, for example, a nut from self-unscrewing while the machine is operating. The cotter pin is inserted into the hole located at the end of the bolt or stud, and then its ends are separated. Adjustable cotter pins must be made from low-carbon steel wire of standard steel grades with a carbon content of no more than 0.20%. In table 17 and on figure 456 The dimensions of the adjustable cotter pins are given.
The length of the cotter pin is selected within the specified limits: up to 12 mm - every 2 mm; from 15 to 50 mm - after 5 mm and from 50 to 100 mm - after 10 mm.
An example of a symbol for a cotter pin with a nominal diameter d = 3 mm, length t = 15 mm: Cotter pin 3 X 15 GOST 397 - 54.
This type of connection refers to fastening detachable connections. It is an assembly unit consisting of a bolt, nut, washer and connecting parts. Typically, bolts are used to connect parts to flanges and when frequent assembly and disassembly of the product is necessary.
Bolt- this is a threaded product, which is a rod that has a thread for a nut at one end, and a head of various shapes at the other. There are a significant number of types of bolts, differing from each other in the shape and size of the head and shank, thread pitch, design and manufacturing accuracy. The most common hex head bolts are made of normal, high and rough precision. Depending on the purpose, hex bolt heads have a normal height according to GOST 7798-70 and a reduced height according to GOST 7796-70 (Appendix A, table A.1, A.2). Each bolt diameter d correspond to certain dimensions of its head. With the same diameter, the bolt can be manufactured in different lengths l, which is standardized. The standard bolt length depends on the thickness of the parts being connected.
Standard bolt length The size is calculated from the threaded end of the rod to the supporting surface of the head. Bolt thread length l O also standardized and set depending on its diameter d and length l.
According to their design features, the following types of bolts are distinguished: 1 - without holes (in the head and shaft), 2 - with a hole for a cotter pin in the shaft, 3 - with two holes in the bolt head (for fastening the heads of a group of bolts with wire).
screw- this is a part with a threaded hole used for screwing a bolt, screw or stud onto the rod and is the closing part of the power circuit of a detachable threaded connection.
The standard provides nuts of various shapes: hexagonal, slotted, wing nuts, cap nuts, etc. Turnkey nuts can be round, square, hexagonal, etc. The most common hexagonal nuts are manufactured in three designs: 1 – with two conical chamfers on the outer surface; 2 – with one chamfer; 3 – without chamfers and with a cylindrical or conical projection at one end of the nut. For standard nuts, metric threads with coarse and fine pitch are used. According to the degree of accuracy, nuts are divided into nuts of normal, increased and rough accuracy. Nuts are divided according to their height into normal, low, high and extra high.
Washer- this is a product placed under a nut, bolt or screw head to increase their supporting surface. The washer is a flat ring of a certain thickness, without threads, with a hole slightly larger than the diameter of the rod.
The configuration of the washers is different. Round washers, manufactured according to GOST 11371-78, have two designs: 1 – without chamfer; 2 – with a chamfer (Appendix A, table A.5).
Spring washers, manufactured according to GOST 6402-70, are a steel ring with a slot and ends spread in different directions. Spring washers are divided into light, normal, heavy and extra heavy (Appendix A, Table A.6).
Simplified and conventional representation of a bolt connection
In assembly drawings of general types, bolt connections are depicted in accordance with GOST 2.315-68 in a simplified and conditional manner (depending on the scale) (Figure 8). The simplified image does not show the chamfers, the gap between the rod and the hole; the thread in the section is carried out to the end of the rod, but in the top view it is not shown. Fasteners whose rod diameters in the drawing are equal to or less than 2 mm are depicted conventionally.
a) simplified, b) conditional
Figure 8 – Images of a bolt connection
Symbols of standard products in bolted connections
For educational purposes, the designation of standard products can be written in a simplified manner.
The following parameters are indicated in the bolt designation: name, version (version 1 is not indicated), diameter, fine pitch, standard bolt length, standard number.
Bolt M 24×2.0×90 GOST 7798-70 - execution bolt 1 d=24mm, with fine thread pitch Р=2.0mm, length L= 90mm.
The nut symbol indicates the following parameters: name, version (version 1 is not indicated), diameter, fine pitch, standard number.
For educational purposes, the nut designation can be written in a simplified manner.
Nut 2M24×2.0 GOST 5915-70 – performance nut 2 , with outer diameter metric thread d=24mm, with fine thread pitch P=2.0mm.
The symbol of the washer includes: name, version (version 1 is not indicated), thread diameter of the fastener rod, standard number.
Washer 24 GOST 6402-70 – washer, with thread diameter of fastener rod 24mm.
Connecting parts with a pin.
A pin connection of parts consists of a stud, nut, washer and fastened parts.
Studs are used for detachable connections of parts in cases where one of the parts being fastened is thick or, due to its design, there is no room for a bolt head.
A stud connection is carried out as follows: in one of the parts to be connected there is a blind or through hole with a thread, and in the other there is a hole without a thread with a diameter of 1.1d, where d is the diameter of the stud.
The stud is screwed at one end into the first hole and passes freely through the second, then, as with a bolted connection, a washer is put on the protruding end of the stud and a nut is screwed on. The depth of the blind hole must be greater than the length of the screwed end of the stud, i.e. The end of the pin should not rest against the bottom of the hole.
The nut and washer are depicted in a simplified manner, as in a bolted connection.
The line defining the thread boundary at the lower end of the stud is always drawn at the level of the surface of the part into which the stud is screwed.
The dimensions of the parts of the simplified connection image are taken depending on the thread diameter of the stud - d, Figure 12.
The resulting stud length l (without the threaded screw-in end) is compared with standard values and the nearest larger standard value is selected.
Standard range of bolt lengths in mm according to GOST 22036-76: 14; 16; (18); 20; (22); 25; (28); thirty; (32); 35; (38); 40; 42; 45; (48); 50; 55; 60; 65; 70; 75; 80; 85; 90; (95); 100; (105); 110; (115); 120.
Magnitude l 1 depends on the material of the part into which the pin is screwed, and determines the standard of the pin:
l 1 = d – for steel, bronze, brass – GOST 22032–76;
l 1 = 1.25d – for malleable and gray cast iron – GOST 22034–76;
l 1 = 2d – for light metals – GOST 22038–76.
Figure 12 – Simplified illustration of connecting parts with a pin
Connecting parts with a screw
A screw connection consists of a screw and two parts to be connected, such as a cover and a housing.
This type of connection is performed as follows: a cover with unthreaded holes is placed on a part with threaded holes (body), and then screws are screwed into the body and the heads press the cover to the body.
The dimensions of the parts of the simplified image of the connection are taken depending on the diameter of the screw thread - d, Figure 13.
The length of the screwed-in (mounting) end of the screws - l1 depends on the material of the parts that have a threaded hole, and is calculated using the same formulas as for a stud connection.
When screws have a slot for gripping with a screwdriver, this slot is conventionally depicted as one solid thick line.
Sheet 2-3 includes 5-7 sketches of the main parts, made according to the assembly drawing. All sketches are done in pencil on squared paper or graph paper. The sequence of the sketch and the requirements for its implementation are set out in the description of sheet 2-1.
Each detail is drawn on a separate sheet. Sheet formats for sketches are chosen independently (in accordance with GOST 2.301-68, taking into account the number of images (types, sections, sections) and their size).
Sketching parts begins with reading the assembly drawing. Using the description of the drawing, you should determine what parts (and in what quantity) the assembly unit consists of, how the parts are connected to each other and their interaction. When analyzing the shape of each part, they focus on the projection connection and shading of the part. Having found the part in all the images, determine the number of views, the main view, the sections necessary to depict it in the drawing. After this, they begin to sketch the part.
You should not copy a part from an assembly drawing, since views and sections in an assembly drawing give an idea of the design of the product, and in a sketch - about the shape of the part. Therefore, when depicting parts, you must remember:
The number of images should be minimal, but quite sufficient to understand the design of the part;
If the design of the part is symmetrical, the full cut can be omitted by connecting half of the part's appearance to the cut;
It is advisable to place the image of the part as it is installed in the machine during processing or in the product;
The image should occupy 70% of the sketch area, according to this the size of the images on the sketch is selected;
When making a sketch of a part, they determine what dimensions need to be put in order to manufacture the depicted part.
Usually, dimensions for drawings of parts are taken from the contours of the assembly drawing, since there are only a few nominal dimensions in the drawing - these are overall, connecting, installation and some others, but we are interested in all the dimensions necessary for the manufacture of the part. In this manual, printed drawings do not have a specific (standard) scale.
In order to determine the true dimensions of the part, it is necessary to find out how many times the assembly drawing is reduced (or enlarged) during printing. For this purpose, find the largest size in the drawing (the larger the size, the smaller the error in the calculation). For example, size 120, when directly measured in the figure, turned out to be equal to 52 mm. Dividing 120 by 52 gives a reduction factor of approximately 2.307. Now, in order to find out the dimensions not indicated on the assembly drawing, you need to measure them on the drawing and multiply the resulting values by 2.307.
The main inscription is drawn up according to the description of the assembly drawings given in this manual. The designation of the drawing is entered in the frame located in the upper left corner (frame size 70×14). In this case, the designation is rotated 180°.
Simplifications of images allowed in the assembly drawing should not be mechanically transferred to sketches of parts. For example, grooves and chamfers that are not shown on the assembly drawing are drawn according to GOST 10549-80. Elements of parts that are not shown on the assembly drawing are drawn on the sketches: casting and stamping slopes, tapers, roundings, fillets, etc.
Fasteners are used to connect various parts of structures. To the fastener (which is what is often called in everyday life fasteners) include screws, bolts, nuts, self-tapping screws, screws, rivets, studs, pins, washers, dowels, etc.
In technology, one of the most important and widespread detachable connections is the bolted one. Its main advantage is that when using it, it is not necessary to cut threads on the parts that are fastened together. This feature of a bolted connection is especially important when the material from which the parts being connected are made is not able to provide the required thread strength and durability.
Bolted connections also have their disadvantages. These include, for example, that to implement it, there must be enough space on the parts being connected to accommodate the head of a screw or nut. In addition, during the process of screwing or unscrewing nuts, you need to hold the screw head to prevent rotation. It should also be noted that compared to, say, a screw connection, a bolted connection leads to a greater increase in the mass of the finished product.
If for some reason it is impossible to install a bolted connection or it turns out to be irrational, then screws and studs are used. This, for example, is usually done when there is no way to provide access to the head (nut) or there is simply no space to place it. Another common case is the significant thickness of the parts, which results in the need for deep drilling and the use of long bolts.
Washers are used as backing elements. They are installed under the heads of screws or nuts in order to reduce the degree of deformation of parts by clamping elements when they are made of not very durable material (for example, wood, aluminum, plastic, etc.). In addition, with the help of washers, it is possible to prevent parts from being scratched when screwing a screw or nut, and also to compensate for significant hole clearance. As practice shows, using washers in other cases does not make much sense. If it is necessary to protect the connection from self-unscrewing, then safety or lock washers are also used.
Simplified and conventional images on general view drawings and assembly drawings images fasteners for all industries and construction are established by a document such as GOST 2.315 - 68.
The choice of a conventional or simplified image of fasteners in general view drawings and assembly drawings is made depending on the exact scale and purpose of each specific technical document. Conventional images are used for those fasteners whose rod diameters, when depicted in the drawings, are 2 millimeters or less. In this case, the rule that a complete picture of the nature of the connection must be given should be fully observed.
The use of conventional and simplified images of fasteners should be carried out in accordance with the tables below.
| Simplified and conventional images of fasteners | ||
| Simplified image |
Conditional image |
Name |
| Hex Bolts | ||
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Square Head Bolts | |
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Hammer Head Bolts | |
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Button head bolts | |
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Round Head Hinge Bolts | |
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Swivel bolts with fork | |
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Foundation bolts | |
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Button head screws | |
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Pan head screws | |
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Pan Head and Sphere Screws | |
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Phillips Button Head Screws | |
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Phillips Pan Head Screws | |
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Allen screws | |
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Countersunk head screws | |
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Countersunk screws | |
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Countersunk Phillips Screws | |
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Self-tapping screws with cylindrical head |
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Self-tapping screws with a countersunk cross head | |
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Round nuts | |
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Hex nuts | |
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Hexagon slotted and castle nuts | |
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Wing nuts | |
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|
Round head screws |
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Countersunk screws | |
|
Countersunk head screws | |
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Hairpins | |
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Plain washers, lock washers, etc. |
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Lock washers with tongue |
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|
Spring washers |
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Cylindrical pins | |
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Conical pins | |
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Nails | |
| Cotter pins | ||
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Threaded inserts | |
| Examples of simplified and conditional images fasteners in connections |
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| Simplified image | Conditional image |
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If objects on assembly drawings have several similar connections in their design, then the fasteners included in them in one or two places of each of them should be depicted in a simplified or conditional manner, and in other places it is enough to simply use axial or center lines.
Designation of fasteners in the drawing
In cases where the drawing contains a number of fastening groups that differ in size and type, it is better to apply them using symbols, indicating the position number only once.
If there are identical fastening groups on the construction drawings, then it is permissible to outline them with a thin solid line, and make an explanatory inscription on the leader shelf. As for the predominant fasteners, they are not outlined and are not specified in the general instructions for the drawing.
Same fasteners
To depict the slots on the fastener heads, one solid line is used.
Designation of splines in the drawing
In cases where the slot line drawn at an angle of 45° to the drawing frame coincides with the center line or is close to it, then it is drawn at an angle of 45° to the center line.
Spline designation
Examples of symbols for various standard products:
Bearing 36203 GOST 831-75;
Oiler I.2.Ts6 GOST 19853-74;
Hairpin 2М12-6g×60.58 GOST 22032-76.
A block diagram of the symbol for bolts, screws, studs and nuts is presented in Figure 29.
Figure 29
For educational purposes, in the symbol designation of bolts, screws, studs and nuts, version 1 is accepted and the thread pitch is large (not indicated), the thread tolerance range, strength class and material grade are not indicated, without coating .
Example of a symbol for a bolt with a nominal thread diameter d=16mm, with large steps Р=2mm(not specified), length l=120mm, GOST 7798-70:
Bolt M16×120 GOST 7798-70.
An example of a symbol for a stud with a nominal thread diameter d=16mm, with large steps Р=2mm(not specified), length l=120mm,GOST 22032-76:
Hairpin M16×120 GOST 22032-76.
An example of a symbol for a nut, with a nominal thread diameter d=12mm, with large steps R=1.75mm, GOST 5915-70:
Nut M12 GOST 5915-70.
The block diagram of the washers symbol includes the following set of parameters (Fig. 30):
Figure 30
For educational purposes, the material group or grade of material is not indicated in the symbol for washers, without coating .
An example of a washer symbol for a fastener with a nominal thread diameter d=12mm, GOST 11371-78:
Washer 12 GOST 11371-78.
Specification
As noted earlier, the specification is the main design document that defines the composition of an assembly unit, complex, kit, and is intended for completing design documents, planning the launch of a product into production and its manufacture. The form and rules for fulfilling specifications are established by GOST 2.106-96.
A specification is a text document in the form of a table. The specification is drawn up on separate A4 sheets for each assembly unit, complex and kit.
Figure B.1 of Appendix B shows an image of the specification sheet.
It is necessary to distinguish between the first and subsequent sheets of the specification. The difference is only in the form of the main inscription, carried out in accordance with GOST 2.104-2006. Form 2 is used on the first sheet, and Form 2a is used on subsequent sheets. The form of the title block is shown in Figure B.2 of Appendix B.
Specification Sections
The specification, in general, consists of sections, which are arranged in the following sequence:
· documentation;
· complexes;
· Assembly units;
· details;
· Standard products;
· Other products;
· materials;
· kits.
The presence of certain sections is determined by the composition of the specified product.
The name of each section is indicated as a heading in the “Name” column and underlined with a solid thin line. There is always one blank line left between the section title and its contents.
After each section of the specification, it is necessary to leave several free (at least one) lines (reserve) for additional records, depending on the stage of development, the volume of records, etc.
Section "Documentation". This section includes documents that make up the main set of design documents for the product being specified, for example, an assembly drawing, a circuit diagram, technical specifications, operational documents, in addition to its specifications.
Documents are recorded in alphabetical order by combining letters of codes of developing organizations (initial letters) in the document designation. Within these codes - in ascending order of the classification characteristics of the product (increasing numbers included in the designation). For example:
ABVG.013400.000 SB
AGLR.122301.000 SB
AGLR.122302.000 SB
AGLR.150101.000 SB.
Since the “Documentation” section is not an integral part of the specified product, then, regardless of the composition of the product itself, this section is always present in the specification. The exception is when the specification is combined with an assembly drawing. In this case, the “Documentation” section is not created.
Sections “Complexes”, “Assembly units”, “Parts”. These sections include complexes, assembly units and parts directly included in the specified product. Products are recorded in the same order as documents in the “Documentation” section. For parts for which drawings have not been issued, indicate the name, material and other data necessary for manufacturing.
Section "Standard Products". This section records products used in accordance with state and industry standards.
By groups of products, combined according to their functional purpose (for example, bearings, fasteners, electrical products, etc.);
Within each group - in alphabetical order of product names, for example:
BoltМ6×20.58.015 GOST 7798-70
ScrewМ10×55.58 GOST 1491-80
screw M6.5 GOST 5915-70
Washer 6.01 GOST 11371-78;
Within each name - in ascending order of standard designations, for example:
Washer 6.40Х GOST 6402-70
Washer 6.01 GOST 11373-78
Within each standard designation - in ascending order of the main parameters or dimensions of the product, for example:
Bolt M6×20.58.015 GOST 7798-70
Bolt M6×30.58.015 GOST 7798-70
Bolt M8×20.58.015 GOST 7798-70.
Section "Other products". The section includes products used according to technical specifications (TU).
It is allowed to combine the sections “Standard Products” and “Other Products” under the name “Other Products”. In this case, products are recorded as for the “Other products” section.
Section "Materials". The “Materials” section includes all materials directly included in the specified product.
Within each type of material, it is recommended to record in alphabetical order of names, and within each name - in ascending order of size or other technical parameters.
The “Materials” section does not record those materials the required quantity of which cannot be determined by the designer based on the dimensions of the product elements and, as a result, is installed by the technologist. Such materials include varnishes, paints, glue, lubricants, putties, solders, electrodes, etc. Indications on the use of such materials are given in the technical requirements on the drawing field.
Section "Kits". The following documents are entered into the “Kits” section:
· list of operational documents;
· list of documents for repairs;
· set of mounting parts;
· set of replacement parts;
· Spare parts;
· a set of tools and accessories;
· a set of styling products;
· other sets (with the names assigned to them);
· package.
Specification graphs.
Column "Format" . The column indicates the symbols of standard formats (GOST 2.301-68) only for those documents whose designations are written in the “Designation” column. These are documents listed in the sections “Documentation”, “Complexes”, “Assembly units” and “Parts”. For documents recorded in the sections “Standard products”, “Other products” and “Materials”, the column is not filled in.
For parts for which drawings have not been issued, the column indicates: warhead.
Column "Zone" . The column is filled in only if the drawing field is divided into zones in accordance with GOST 2.104-2006. In this case, in the “Zone” column indicate the designation of the zone in which the position number of the recorded component is located, for example A3, B1, B4;
Column "Pos." (position). The column indicates the serial numbers of the components directly included in the product being specified, in the sequence in which they are recorded in the specification. The numbering should be continuous through all sections, starting from the first section of the next one, after the “Documentation” section. It is allowed to reserve item numbers that are entered into the specification when filling out reserve lines. For sections “Documentation” and “Kits” the column is not filled in;
Column "Designation" . The column indicates:
· in the “Documentation” section - designation of the recorded documents for which the specification is drawn up;
· in the sections “Complexes”, “Assembly units”, “Parts” and “Kits” - designations of the main design documents. For parts for which drawings have not been issued - the designation assigned to them.
In the sections “Standard products”, “Other products” and “Materials” the column is not filled in;
Column "Name" . The column indicates:
· in the “Documentation” section for documents included in the main set of documents of the specified product and compiled for this product - only the name of the documents, for example: “Assembly drawing”, “Dimensional drawing”;
· in the sections “Complexes”, “Assembly units”, “Parts”, “Kits” - names of products in accordance with the main inscription on the main design documents of these products.
· in the “Standard Products” section - names and designations of products in accordance with the standards for these products;
· in the “Materials” section - designations of materials established in the standards or technical specifications for these materials.
The number of lines allocated for recording any component of the specified product is not limited.
Column "Count." (quantity). The column indicates for the component parts of the product recorded in the specification, their quantity per one specified product. The numerical value defining this quantity is entered in the first of all lines allocated for recording this component in the “Name” column.
In the “Documentation” section, the column is not filled in;
Column "Note". The column indicates additional information for planning and organizing production, as well as other information related to the products, materials and documents recorded in the specification, for example, for parts for which drawings have not been issued - weight.
More detailed information about the rules for fulfilling the specification is presented in GOST 2.106-96.
Assembly drawing
An assembly drawing (SB code) is a working document containing images of an assembly unit (views, sections, sections), dimensions and other data necessary only for its assembly and control. If necessary, assembly drawings provide data on the operation of the product and the interaction of its parts.
The letters “SB” are added to the designation of the product (assembly unit), which is written in the corresponding column of the main inscription of the assembly drawing, for example: GR20.020318.000 SB. There is no dot between the designation of the assembly unit “GR20.020318.000” and the code “SB”.
The assembly drawing must contain:
· images of the assembly unit, giving an idea of the location and mutual connection of the components connected according to this drawing, and providing the ability to assemble and control the assembly unit. It is allowed to place additional schematic images of the connection and location of the component parts of the product on assembly drawings;
· dimensions, maximum deviations and other parameters and requirements that must be met or controlled according to this assembly drawing;
· instructions on the nature of the interface and methods for its implementation, if the accuracy of the interface is ensured not by specified maximum dimensional deviations, but by selection, fitting, etc., as well as on the implementation of permanent connections (welded, soldered, glued, etc.);
· position numbers of the components included in the product (from the specification);
· overall dimensions of the product;
· installation, connecting and other necessary reference dimensions;
· technical characteristics of the product (if necessary);
· coordinates of the center of mass (if necessary).