parlini.ru Repair of apartments, villas and houses.
Let the main view and the top view be known. It is necessary to build a left view.
To build the third type according to two known methods, two main methods are used.
The construction of the third type using the auxiliary line.
In order to transfer the size of the part width from the top view to the left view, it is convenient to use the auxiliary line (Fig. 27a, b). It is more convenient to draw this straight line to the right of the top view at an angle of 45 ° to the horizontal direction.
To build a third projection A 3 peaks Adraw through its frontal projection A 2 horizontal line 1 . It will contain the desired projection. A 3. After that, through a horizontal projection A 1 draw a horizontal line 2 until it intersects with the auxiliary line at the point A 0. Through point A 0 draw a vertical line 3 before crossing straight 1 at the desired point A 3.
Similarly, profile projections of the remaining vertices of the subject are constructed.
After the auxiliary straight line is drawn at an angle of 45 °, the construction of the third projection is also conveniently carried out using a rake and a triangle (Fig. 27b). First through the frontal projection A 2 draw a horizontal line. Draw a horizontal line through the projection A 1there is no need, it is enough, having attached a raiser, to make a horizontal notch at a point A 0 on the auxiliary line. After that, having slightly shifted the neck down, we apply the square with one leg to the neck so that the second leg passes through the point A 0, and note the position of the profile projection A 3.
Building a third view using baselines.
To build the third type, it is necessary to determine which lines of the drawing should be taken as the base lines for counting the sizes of the images of the object. As such lines, axial lines (projections of the symmetry planes of the object) and projections of the planes of the base of the object are usually taken. Let us examine an example (Fig. 28) of constructing a left view from two given projections of an object.
Fig. 27 Construction of the third projection using two data
Fig. 28. The second method of constructing a third projection from two data
Comparing both images, we establish that the surface of the object includes the surface: regular hexagonal 1 and quadrangular 2 prisms, two cylinders 3 and 4 and truncated cone 5 . The item has a frontal plane of symmetry. F, which is convenient to take as the basis for measuring the size of the width of individual parts of the object when constructing its left view. The heights of individual sections of the subject are counted from the lower base of the subject and are controlled by horizontal communication lines.
The shape of many objects is complicated by various slices, cutouts, intersection of component surfaces. Then you first need to determine the shape of the intersection lines, build them at individual points, introducing the designations of the projections of the points, which after completing the construction can be removed from the drawing.
In fig. 29, a left side view of an object is constructed whose surface is formed by the surface of a vertical cylinder of revolution with T-shaped notch in its upper part and a cylindrical hole occupying a frontal projection position. The base planes are the plane of the lower base and the frontal plane of symmetry F. Picture T-shaped cut in the left view is constructed using dots A, B, C, D and Ethe contour of the cut, and the line of intersection of the cylindrical surfaces with the help of points K, L, M and im symmetrical. When constructing the third type, the symmetry of the object relative to the plane was taken into account F.
Fig. 29. Building a left view
5.2.3. Construction of transition lines. Too many details contain lines of intersection of all kinds of geometric surfaces. These lines are called transition lines. In fig. 30 shows the bearing cap, the surface of which is limited by the surfaces of rotation: conical and cylindrical.
The intersection line is constructed using auxiliary clipping planes (see section 4).
The characteristic points of the intersection line are determined:
1) points, the highest and lowest in relation to the plane N 1, eg, 1 and 6, 6 ¢;
Date of introduction 01.01.71
This standard establishes the rules for depicting objects (products, structures and their components) in the drawings of all industries and construction. The standard fully complies with ST SEV 363-88. (Amended edition, Amendment No. 2).
1. BASIC PROVISIONS AND DEFINITIONS
1.1. Images of objects should be performed using the rectangular projection method. In this case, the object is supposed to be located between the observer and the corresponding projection plane (Fig. 1).1.2. For the main projection planes take six faces of the cube; faces align with the plane, as shown in the drawing. 2. Face 6 is allowed to be located next to face 4. 1.3 The image on the frontal plane of projections is accepted as the main one in the drawing. The object is positioned relative to the frontal plane of the projections so that the image on it gives the most complete picture of the shape and size of the object. 1.4. The images in the drawing, depending on their content, are divided into types, sections, sections.
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1.5. View - the image of the visible part of the surface of the object facing the observer. To reduce the number of images, it is allowed to show the necessary invisible parts of the surface of the object using dashed lines (Fig. 3).
1.6 Section - the image of an object mentally dissected by one or several planes, while the mental section of an object refers only to this section and does not entail changes in other images of the same object. The section shows what is obtained in the secant plane and what is located behind it (Fig. 4). It is allowed to depict not everything that is located beyond the secant plane, if this is not required to understand the design of the object (Fig. 5).
1.7. Section - an image of a figure resulting from the mental dissection of an object by one or more planes (Fig. 6). The section shows only what is obtained directly in the secant plane. It is allowed to use a cylindrical surface as a secant, which is then deployed into a plane (Fig. 7).
(Amended edition, Amendment No. 2). 1.8. The number of images (types, sections, sections) should be the smallest, but providing a complete picture of the subject when applying the conventions, signs and inscriptions established in the relevant standards.
2. TYPES
2.1. The following names of the species obtained on the main planes of projections are established (main types, Fig. 2): 1 - front view (main view); 2 - top view; 3 - view from the left; 4 - view from the right; 5 is a bottom view; 6 is a rear view. In construction drawings, if necessary, other types may be assigned to the corresponding types, for example, “facade”. The names of the species in the drawings should not be inscribed, with the exception of the case provided for in paragraph 2.2. In construction drawings, it is allowed to inscribe the name of the species with the assignment of an alphabetic, digital or other designation to it. 2.2. If the top, left, right, bottom, rear views are not in direct projection communication with the main image (view or section shown on the frontal plane of projections), then the design direction should be indicated by an arrow near the corresponding image. The same uppercase letter should be applied above the arrow and above the received image (view) (Fig. 8).
Drawings are drawn up in the same way if the listed types are separated from the main image by other images or are not located on one sheet with it. When there is no image on which the direction of view can be shown, the name of the species is inscribed. In construction drawings, it is allowed to indicate the direction of view with two arrows (similar to indicating the position of secant planes in sections). In construction drawings, regardless of the relative position of the views, it is allowed to inscribe the name and designation of the view without indicating the direction of view with an arrow if the direction of view is determined by the name or designation of the view. 2.3. If any part of the object cannot be shown on the types listed in Section 2.1 without distorting the shape and size, then additional types are used, obtained on planes that are not parallel to the main planes of the projections (Fig. 9-11). 2.4. An additional view shall be marked on the drawing with an uppercase letter (Fig. 9, 10), and the object associated with the additional image must be marked with an arrow indicating the direction of view, with the corresponding letter designation (arrow B, Fig. 9, 10).
When an additional view is located in direct projection connection with the corresponding image, the arrow and designation of the view are not applied (Fig. 11).
2.2-2.4. (Amended edition, Amendment No. 2). 2.5. Additional views are positioned as shown in the drawing. 9-11. Location of additional views to hell. 9 and 11 are preferred. An additional view may be rotated, but with the preservation, as a rule, of the position adopted for the subject in the main image, while the type designation must be supplemented by a conventional graphic designation. If necessary, indicate the angle of rotation (Fig. 12). Several identical additional species related to one subject are denoted by one letter and one species is drawn. If at the same time the parts of the object associated with the additional view are located at different angles, then the conditional graphic designation is not added to the type designation. (Amended edition, Amendment No. 1, 2). 2.6. The image of a separate, limited surface area of \u200b\u200ban object is called a local view (view D, drawing 8; view D, drawing 13). The local view may be limited by the cliff line, if possible in the smallest possible size (view D, drawing 13), or not limited (view D, drawing 13). The local view should be marked on the drawing like an additional view. 2.7. The ratio of the size of the arrows indicating the direction of view should correspond to those shown in the drawing. 14. 2.6, 2.7. (Amended edition, Amendment No. 2).
3. CUTS
3.1. Sections are divided, depending on the position of the secant plane relative to the horizontal plane of the projections, into: horizontal - the secant plane is parallel to the horizontal plane of the projections (for example, section A-A, figure 13; section B-B, figure 15). In construction drawings, horizontal sections may be given other names, for example, “plan”; vertical — the secant plane is perpendicular to the horizontal plane of the projections (for example, a section at the site of the main view, drawing 13; sections AA, BB, GG, drawing 15); inclined — the secant plane makes an angle different from the straight line with the horizontal projection plane (for example, a section B-B, Fig. 8). Depending on the number of secant planes, the sections are divided into: simple - with one secant plane (for example, drawing 4, 5); complex - with several secant planes (for example, section AA, drawing 8; section BB, drawing 15). 3.2. A vertical section is called frontal if the cutting plane is parallel to the frontal plane of the projections (for example, section, drawing 5; section AA, drawing 16), and profile if the cutting plane is parallel to the profile plane of projections (for example, section BB, drawing . 13).
3.3. Complex sections are stepped if the secant planes are parallel (for example, a stepped horizontal section B-B, figure 15; a stepped frontal section A-A, figure 16), and broken if the secant planes intersect (for example, sections A-A, Fig. 8 and 15). 3.4. Sections are called longitudinal if the secant planes are directed along the length or height of the object (Fig. 17), and transverse if the secant planes are directed perpendicular to the length or height of the object (for example, sections A-A and B-B, Fig. 18). 3.5. The position of the secant plane is indicated on the drawing by a section line. An open line should be used for the section line. With a complex cut, strokes are also carried out at the intersection of the secant planes with each other. On the initial and final strokes, arrows should be placed indicating the direction of the gaze (Fig. 8-10, 13, 15); arrows should be applied at a distance of 2-3 mm from the end of the stroke. The start and end strokes must not cross the contour of the corresponding image. In cases similar to those indicated in the devil. 18, arrows indicating a direction of view are plotted in a single line. 3.1-3.5. (Amended edition, Amendment No. 2). 3.6. At the beginning and end of the section line, and, if necessary, at the intersection of secant planes, put the same capital letter of the Russian alphabet. The letters are applied near the arrows indicating the direction of view, and at the intersection from the side of the outer corner. The section must be marked with an inscription of the type “AA” (always in two letters through a dash). In construction drawings, at the section line instead of letters, it is allowed to use numbers and also inscribe the name of the section (plan) with the assigned alphanumeric or other designation. 3.7. When the secant plane coincides with the plane of symmetry of the object as a whole, and the corresponding images are located on the same sheet in direct projection communication and are not separated by any other images, the position of the secant plane is not noted for horizontal, frontal and profile cuts, and the cut is labeled do not accompany (for example, a section at the site of the main view, Fig. 13). 3.8. Frontal and profile sections, as a rule, give the position corresponding to that adopted for this subject in the main image of the drawing (Fig. 12). 3.9. Horizontal, frontal and profile sections can be located on the site of the corresponding main types (Fig. 13). 3.10. A vertical section, when the secant plane is not parallel to the frontal or profile planes of the projections, as well as the inclined section, must be constructed and arranged in accordance with the direction indicated by the arrows on the section line. It is allowed to place such cuts anywhere in the drawing (section B-B, Fig. 8), as well as with rotation to a position corresponding to that adopted for the subject in the main image. In the latter case, a conditional graphic designation should be added to the inscription (section G-D, Fig. 15). 3.11. In case of broken cuts, the secant planes are conditionally rotated until they are aligned in one plane, while the direction of rotation may not coincide with the direction of view (Fig. 19). If the combined planes turn out to be parallel to one of the main planes of the projections, then the broken section is allowed to be placed in the place of the corresponding type (sections AA, Fig. 8, 15). When the secant plane is rotated, the elements of the object located on it are drawn as they are projected onto the corresponding plane with which it is aligned (Fig. 20).
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3.12. The section, which serves to determine the structure of the subject only in a separate, limited place, is called local. A local section is distinguished in the form by a solid wavy line (Fig. 21) or a solid thin line with a kink (Fig. 22). These lines should not coincide with any other image lines.
3.13. Part of the species and part of the corresponding section may be combined, separating them with a solid wavy line or a continuous thin line with a kink (Fig. 23, 24, 25). If at the same time half of the view and half of the section are connected, each of which is a symmetrical figure, then the axis of symmetry serves as the dividing line (Fig. 26). It is also possible to separate the section and the type by a dash-dotted thin line (Fig. 27), which coincides with the trace of the plane of symmetry of not the whole object, but only its part, if it represents a body of revolution.
3.10-3.13. (Amended edition, Amend. № 2). 3.14. It is allowed to combine a quarter of the view and a quarter of three sections: a quarter of the view, a quarter of one section and half of the other, etc., provided that each of these images separately is symmetrical.
4. SECTIONS
4.1. Sections that are not part of the section are divided into: rendered (Fig. 6, 28); superimposed (damn. 29).
Spaced out sections are preferred and may be placed in a section between parts of the same type (Fig. 30).
(Amended edition, Amendment No. 2). 4.2. The contour of the extended section, as well as the section included in the section, is represented by solid main lines, and the contour of the superimposed section is shown by solid thin lines, and the image contour is not interrupted at the location of the superimposed section (Fig. 13, 28, 29). 4.3. The axis of symmetry of the taken out or superimposed section (Fig. 6, 29) is indicated by a dash-dotted thin line without letters and arrows and the section line is not drawn. In cases similar to those indicated in the devil. 30, with a symmetrical cross-sectional shape, the cross-section line is not drawn. In all other cases, an open line is used for the section line with the direction arrows pointing and designate it with the same uppercase letters of the Russian alphabet (in construction drawings - with uppercase or lowercase letters of the Russian alphabet or numbers). The section is accompanied by an inscription of the type “AA” (Fig. 28). In construction drawings, the name of the section may be inscribed. For asymmetric sections located in the gap (Fig. 31) or superimposed (Fig. 32), the section line is drawn with arrows, but is not indicated by letters.
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In construction drawings with symmetrical sections, an open line is used with its designation, but without arrows indicating the direction of view. 4.4. The section by construction and location should correspond to the direction indicated by the arrows (Fig. 28). It is allowed to place the section anywhere on the drawing field, as well as rotate it with the addition of a conventional graphic symbol 4.5. For several identical sections related to the same subject, the section line is denoted by one letter and one section is drawn (Fig. 33, 34). If in this case the secant planes are directed at different angles (Fig. 35), then the conventional graphic designation is not applied. When the location of identical sections is precisely determined by the image or by dimensions, it is allowed to apply one section line, and indicate the number of sections above the section image.
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4.6 The secant planes are chosen so as to obtain normal cross sections (Fig. 36). 4.7. If the secant plane passes through the axis of the surface of revolution bounding the hole or recess, then the contour of the hole or recess in the section is shown completely (Fig. 37). 4.8. If the section is obtained consisting of separate independent parts, then sections should be used (Fig. 38).
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4.4-4.8. (Amended edition, Amendment No. 2).
5. OUTDOOR ELEMENTS
5.1. Detail element - an additional separate image (usually enlarged) of any part of the subject, requiring graphic and other explanations regarding the shape, size and other data. The external element may contain details not indicated on the corresponding image, and may differ from it in content (for example, the image may be a view, and the external element may be a cut). 5.2. When using the extension element, the corresponding place is marked on the view, section or section with a closed solid thin line - circle, oval, etc., with the extension element marked with a capital letter or a combination of an uppercase letter with an Arabic numeral on the leader line shelf. Above the image of the extension element indicate the designation and scale at which it is made (Fig. 39).
In construction drawings, the extension element in the image may also be marked with a curly or square bracket or not graphically marked. In the image from where the element is taken out, and in the remote element, it is also possible to apply a letter or numeral (in Arabic numerals) assigned to the remote element and name. (Amended edition, Amendment No. 2). 5.3. The remote element is positioned as close as possible to the corresponding place in the image of the object.
6. TERMS AND SIMPLIFICATIONS
6.1. If the view, section, or cross-section is a symmetrical figure, it is allowed to draw half of the image (view B, plot 13) or a little more than half of the image with a break line drawn in the latter case (draw 25). 6.2. If an object has several identical, evenly spaced elements, then one or two such elements (for example, one or two holes, figure 15) are completely shown on the image of this object, and the remaining elements are shown simplified or conditionally (figure 40). It is allowed to depict a part of the subject (Fig. 41, 42) with appropriate instructions on the number of elements, their location, etc.
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6.3. On views and sections, it is allowed to simplistically depict projections of intersection lines of surfaces, if their exact construction is not required. For example, instead of curve curves, circular arcs and straight lines are drawn (Fig. 43, 44).
6.4. A smooth transition from one surface to another is shown conditionally (Fig. 45–47) or not shown at all (Fig. 48–50).
Simplifications are allowed, similar to those indicated in the devil. 51, 52.
6.5. Parts such as screws, rivets, dowels, hollow shafts and spindles, connecting rods, handles, etc. are shown uncut in longitudinal section. Balls are always shown uncut. As a rule, nuts and washers are shown uncut on assembly drawings. Elements such as flywheel spokes, pulleys, gears, thin walls such as stiffeners, etc., are shown without shading if the secant plane is directed along the axis or long side of such an element. If in such elements of the part there is local drilling, a recess, etc., then make a local cut, as shown in the drawing. 21, 22, 53. (Amended wording, Amendment No. 2).
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6.6. Plates, as well as elements of parts (holes, chamfers, grooves, recesses, etc.) with a size (or a difference in size) in a drawing of 2 mm or less are depicted with a deviation from the scale adopted for the entire image, in the direction of increase. 6.7. Slight tapering or bias is allowed to depict with increasing. In those images in which the slope or taper is not clearly visible, for example, the main view of the devil. 54a or top view of the devil. 54b, only one line is drawn corresponding to a smaller element with a slope or a smaller base of the cone. 6.8. If necessary, highlight on the drawing the flat surfaces of the object on them diagonals are drawn in solid thin lines (Fig. 55). 6.9. Items or elements that have a constant or regularly changing cross section (shafts, chains, rods, shaped bars, rods, etc.) are allowed to be displayed with gaps. Partial images and images with gaps are limited by one of the following methods: a) a solid thin line with a kink, which can extend beyond the image contour to a length of 2 to 4 mm. This line can be inclined relative to the contour line (Fig. 56a);
B) a solid wavy line connecting the corresponding contour lines (Fig. 56b);
C) lines of hatching (Fig. 5BV).
(Amended edition, Amend. № 2). 6.10. On the drawings of objects with a continuous grid, braid, ornament, relief, knurling, etc., it is allowed to depict these elements partially, with a possible simplification (Fig. 57).
6.11. To simplify the drawings or reduce the number of images, it is allowed: a) to depict the part of the object between the observer and the secant plane as a dash-dot thickened line directly on the section (superimposed projection, Fig. 58); b) apply complex sections (Fig. 59);
C) to show the holes in the hubs of gear wheels, pulleys, etc., as well as for keyways, instead of a complete image of the part, give only the outline of the hole (Fig. 60) or groove (Fig. 52); d) depict in section the holes located on the round flange when they do not fall into the secant plane (Fig. 15). 6.12. If the top view is not necessary and the drawing is made up of images on the frontal and profile projection planes, then with a stepwise section, the section line and inscriptions related to the section are applied as shown in the drawing. 61.
6.11, 6.12. (Amended edition, Amendment No. 2). 6.13. Conventions and simplifications allowed in one-piece connections, in the drawings of electrical and radio devices, gears, etc., are established by the relevant standards. 6.14. The graphic symbol “rotated” must correspond to the dash. 62 and "deployed" - damn. 63.
(Introduced additionally, Amendment No. 2). APPENDIX according to GOST 2.317-69.
INFORMATION DATA
1. DEVELOPED AND INTRODUCED by the Committee of Standards, Measures and Measuring Instruments under the Council of Ministers of the USSR V.R. Verchenko, Yu.I. Stepanov, Ya.G. Old-timer, B.Ya. Kabakov, V.K. Anopova 2. APPROVED AND IMPLEMENTED BY Decree of the Committee of Standards, Measures and Measuring Instruments under the Council of Ministers of the USSR in December 1967 3. The standard is fully consistent with ST SEV 363-88 4. REPLACE GOST 3453-59 in terms of sect. I - V, VII and Annexes 5. EDITION (April 2000) with Amendments No. 1, 2, approved in September 1987, August 1989 (IMS 12-87, 12-89)
| 1. The main provisions and definitions. 1 2. Views .. 3 3. Sections .. 6 4. Sections. 9 5. Remote elements .. 11 6. Conventions and simplifications. 12 |
The drawing is one of the main documents from the product documentation package. The designer must make a graphical representation of the part or product so that in any production, for hundreds or thousands of kilometers, they can be made without consulting. In order for the product information to be perceived and interpreted unambiguously, certain uniform rules for the design of drawing images and the location of individual elements on them have been introduced.
Application area
Methods for displaying objects are universal and cover drawings and other design materials of various fields, both construction and industrial. This includes the home appliance, electronics, transportation and communications industries. They regulate how to display objects using two-dimensional drawings and three-dimensional models. The methods, types, arrangement of types of products in the drawing are regulated.
Normative acts
The normative act in this area is GOST 2.305-2008.
Download GOST 2.305-2008 "Images - views, sections, sections."
The document describes in detail the acceptable methods for designating views in the drawings, as well as additional ways of presenting information about the part: sections and sections. Also, it regulates the location of external elements, and the permitted ways to simplify the drawings.
Kinds
The predominant method for representing volumetric products on a plane is orthogonal projection. The location of the depicted object is assumed between the conditional observer and the projection plane. To increase the readability of the image, a simplified approach is allowed. Therefore, the images in the drawings are not projection in the strict geometric sense of the word. They are called plane images. To obtain the main projections, the depicted part is placed in the center of an imaginary cube. Its faces will serve as projection planes.
As a result of the projection of the image of the object, a scheme of the main types of the product appears:
- in front;
- on right;
- from below;
- left;
- from above;
- from behind.
In technical drawing, the front view is considered the main one. It should give maximum information about the displayed part. Its views are complemented by the left and top (relative to the main). These three types are called basic. The rest are considered auxiliary. Their images are built if important structural information about the product of complex shape is not visible in the three main types.
In addition, to explain the structure of part of the part, local views are used, showing a fragment of the image of the main view. Such images are placed in unoccupied areas, inscribed in capital letters of the Cyrillic alphabet. In the main view, in the area where the fragment is located, an arrow is shown showing the direction of the conditional look, as a result of which a local view appears. Such patterns are limited to tear lines drawn in the direction of the minimum element size.
In addition, additional views apply. They are built on planes placed at an angle to the main faces of the projection cube. They help to illustrate the location and structure of those sections of the object that are not visible or not sufficiently informative in the main views, or their dimensions and configuration are distorted. The designation of additional species is carried out by the letters of the Cyrillic alphabet.
A well-thought-out choice of local and additional species allows you to reduce the number of shading when showing the internal structure of the part, invisible on the main projections. The readability of the drawing is also improved, the relative position of its parts, the probability of erroneous interpretation is reduced.
Cuts
To demonstrate the internal structure of an object, it is cut with one or a large number of secants. An image of a part with a volume cut off by such a plane is called a section. It shows the part of the object located in dissecting planes and behind them.
Classification
Cuts are divided into several varieties:
- Simple. One cutting plane is used.
- Complicated. Two or three planes. In especially difficult cases, a larger number is also used.
Simple cuts are divided according to the secant orientation:
- horizontal
- vertical
- inclined.
Complex configurations are divided into step and broken lines.
By the sign of parallelism of the secant of any main plane, the vertical ones are divided into frontal and profile ones. By the same sign, horizontal and frontal are distinguished among step ones.
For axisymmetric objects, sections are also distinguished by the direction of the secant to this axis on:
- longitudinal;
- transverse.
The location of the secant is represented by a thick (one and a half times thicker than the main) dashed line with a dash line length of 8-20 millimeters. The projection direction is indicated by arrows orthogonal to the strokes. The secant plane is called double letters: "AA"
Performance
The image of sections parallel to the plane of the main view are placed near it.
Local sections are separated by wavy lines. When depicting them, avoid placing them in the zone of other elements, coinciding with them or intersecting.
The location of the complex-step section is recommended in the vicinity of the basic reference view. You can place them in free areas of the image.
When displaying broken sections of a section in the drawings, they are rotated so that they are combined into a single hypothetical plane. The location of the parts of the object located behind the rotated plane is hidden.
Sections
If, during the conditional dissection of an object, only that part of it which is in the secant plane is left, section in its drawing understanding.
Sections are divided into:
- being part of a section;
- independent.
Among the independents distinguish:
- Taken out. Draw over the outline of the main view. They are recommended by the standard as preferred.
- Overlaid. They are placed directly on the drawing of the corresponding type or in its gap. Sometimes it makes reading a design document difficult.
The system for the location, designation, and name of sections is similar to the system for designating sections. It is important to remember that lines representing sections cannot intersect drawing elements. The track of the secant is displayed by a thick line with a gap.
Remote elements
If a part of the detail drawing needs a more detailed display than the selected scale of the main drawing allows, the so-called external elements are used.
The location of the extension element in the main view is indicated by a closed loop, most often - round or oval. A thin arrow goes from it to the placement of the detailed image. If such a line is not drawn, the lettering designation of the element is indicated above the extension line, and the letter is repeated above the detailed drawing.
Sometimes an extension may differ from the type of the main image. Display in the form of sections, sections, etc. is allowed.
The location of the extension element indicates detailed linear and angular dimensions, information about accuracy, quality and roughness, as well as other necessary information.
Conventions and simplifications
To facilitate reading and understanding of the drawings, it is allowed to depict the part on them not in 100% accordance with the actual form, using the following conventions and simplifications:
- For parts with a central axis of symmetry, it is allowed to draw half the outline. In the arrangement of the second half, as a rule, a section or section is placed.
- If the design includes several identical elements, in detail, with setting dimensions and tolerances, one of them is displayed, the location of the others is simplified in the form of contours or their number is simply indicated.
- The transition between surfaces is allowed to reflect conditionally or completely omitted.
- Fasteners, spherical elements, shafts, handles, etc. on longitudinal sections draw without dissection.
- For thin-walled parts, an image is enlarged relative to the overall scale.
- For illustrative purposes, it is permissible to increase the angle of the cone or slope.
- Flat edges of the part are distinguished by diagonal thin lines.
- Parts of large length with an unchanged profile are depicted with a gap, marking its places with broken or wavy lines.
- Knurling or notching can be partially depicted.
In some specific cases, additional simplifications are applied. Permissible conventions in the arrangement of certain types of drawings, such as gears, electronic components and devices, etc., are described in the relevant standards.
When simplifying the drawing, the designer should follow the measure so that the document coming out from under his mouse does not turn into a rebus, which will take a long time to solve for the partners.
A complete technical drawing contains at least three projections. However, the knowledge to imagine an object in two projections is required from both a technologist and a skilled worker. It is consequently in the examination tickets in technical universities and colleges that there are continuously problems to build a third type in two given ways. In order to safely complete a similar task, you need to know the conventions adopted in the technical drawing.
You will need
- - paper;
- - 2 projections of the part;
- - drawing instruments.
Instruction manual
1. Abstracts of the third type are identical for classical drawing, sketching and drawing in one of the computer programs prepared for this. Before each, analyze the given projections. See what kind of species are given to you. When it comes to 3 views, this is a general projection, a top view and a left view. Determine what is given to you. This can be done according to the location of the drawings. The left view is located on the right side of the general, and the top view is below it.
2. Establish a projection link with one of the preset views. This can be done by extending the horizontal lines that limit the silhouette of the object to the right, when you want to erect a left view. If it’s a top view, continue down the vertical lines. In any case, one of the part parameters in your drawing will appear mechanically.
3. Find the 2nd parameter on the existing projections that limits the silhouettes of the part. When constructing the left view, you will find this size in the top view. When establishing a projection connection with the main view, the height of the part appeared on the drawing. So, from the top view you need to take the width. When building a top view, the 2nd size is taken from the side projection. Designate the silhouettes of your object in the third projection.
4. See if the part has protrusions, voids, holes. All this is noticed on the general projection, which by definition should give the most accurate picture of the subject. The same is true as in the determination of the overall silhouette of the part in the third projection, establish the projection relationship between the different elements. The remaining parameters (say, the distance from the center of the hole to the edge of the part, the depth of the protrusion, etc.), find in the side view or top view. Build the necessary elements, considering the measurements you have discovered.
5. In order to check how faithfully you have mastered the task, try to draw the part in one of the axonometric projections. Look at how intelligently the elements of the third type drawn by you on the three-dimensional projection are located. It may be hefty that some adjustments will have to be made to the drawing. A drawing with a perspective may also help to check your construction.
One of the most interesting tasks of descriptive geometry is the construction of a third kind of for given 2. It requires a thoughtful approach and shallow measurement of distances; consequently, it is not invariably given the first time. Nevertheless, if one carefully follows the recommended sequence of actions, the construction of the 3rd view is absolutely permissible, even without spatial imagination.
You will need
- - paper;
- - a pencil;
- - ruler or compass.
Instruction manual
1. First, try the two available kind of m determine the shape of the individual parts of the depicted object. If a triangle is shown in the top view, then it can be a triangular prism, a cone of rotation, a triangular or quadrangular pyramid. The shape of a quadrangle can take a cylinder, a quadrangular or triangular prism or other objects. A circle-shaped image may indicate a ball, cone, cylinder, or other surface of revolution. One way or the other, try to imagine the universal form of the subject as a whole.
2. Draw the boundaries of the planes, for the convenience of transferring lines. Start the transfer with the most comfortable and distinct element. Take every point you truly “see” on both kind of x and transfer it to the 3rd view. To do this, lower the perpendicular to the boundaries of the planes and continue it on the further plane. Please note that when switching from kind of on the left in a top view (or opposite), you need to use a pair of compasses or measure the distance with a ruler. So in place of your third kind of two straight lines intersect. This will be the projection of the selected point on the 3rd view. In the same way, it is allowed to carry as many desired points as you can until you see a universal view of the detail.
3. Check the correct construction. To do this, measure the dimensions of those parts of the part that are fully reflected (say, a standing cylinder will be of one “height” in the left view and front view). In order to realize that you have not forgotten anything, try to look at the front view from the position of the observer from above and recount (though approximately) how many boundaries of holes and surfaces should be visible. All direct, every point must be reflected on all kind of x If the part is symmetrical, do not forget to notice the axis of symmetry and check the equality of both parts.
4. Remove all auxiliary lines, check that all visible lines are marked with a dashed line.
In order to depict one or another object, first depict its individual elements in the form of simple figures, and then their projection is performed. Projection is often used in descriptive geometry.
You will need
- - a pencil;
- - compass;
- - ruler;
- - reference book "Descriptive geometry";
- - elastic.
Instruction manual
1. Thoroughly read the data of the task: for example, given the general projection F2. The point F belonging to it is located on the lateral surface of the cylinder of revolution. Construction of 3 projections of point F. is required. Imagine how all this should look, then proceed to the construction of the image on paper.
2. The rotation cylinder can be represented as a rotating rectangle, one of the sides of which is taken as the axis of rotation. The second side of the rectangle - opposite the axis of rotation - forms the side surface of the cylinder. The remaining two sides represent the lower and upper base of the cylinder.
3. Due to the fact that the surface of the cylinder of rotation when constructing the given projections is in the form of a horizontally projecting surface, the projection of the point F1 must certainly coincide with the point P.
4. Draw a projection of the point F2: from the fact that F is on the common surface of the cylinder of rotation, the point F2 will be projected onto the lower base point F1.
5. Build the third projection of the point F using the ordinate axis: set aside F3 on it (this projection point will be located to the right of the z3 axis).
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Note!
When constructing image projections, follow the basic rules used in descriptive geometry. Otherwise, projections will fail.
Helpful advice
In order to build an isometric image, use the upper base of the rotation cylinder. To do this, first build an ellipse (it will be placed in the x’O’y plane). Later on, draw tangent lines and a lower half-ellipse. After that, draw a coordinate polyline and, with its support, build a projection of the point F, that is, the point F ’.
There are not so many people in our time who have never in their life ever drafted or painted something on paper. The knowledge to execute a primitive drawing of any design is rarely more than suitable. It is allowed to spend a lot of time explaining “on the fingers” how one or the other thing was done, while sometimes one glance at her drawing is satisfied in order to realize this without every word.
You will need
- - Whatman paper;
- - drawing accessories;
- - drawing board.
Instruction manual
1. Select the sheet format on which the drawing will be executed - in accordance with GOST 9327-60. The format should be such that it is allowed to place the main kinds the details at the appropriate scale, as well as all the necessary cuts and sections. For simple parts, choose the format A4 (210x297 mm) or A3 (297x420 mm). The 1st can be located on its long side only vertically, the 2nd - vertically and horizontally.
2. Draw the frame of the drawing, departing from the left edge of the sheet 20 mm, from the remaining 3 - 5 mm. Draw a title block - a table in which all data about the details and drawing. Its dimensions are determined by GOST 2.108-68. The width of the core inscription is constant - 185 mm, the height varies from 15 to 55 mm, depending on the purpose of the drawing and the type of institution for which it is performed.
3. Select the scale of the main image. Allowable scales are determined by GOST 2.302-68. They should be preferred so that all the basic elements are perfectly visible in the drawing. the details . If at the same time some places are not clearly visible, they can be transferred in a separate view, showing with the desired increase.
4. Choose main image the details . It should be such a direction of gaze at the part (projection direction) from which its design is revealed especially fully. In most cases, the main image is the location in which the part is on the machine during the core operation. Parts with an axis of rotation are located on the main image, as usual, so that the axis has a horizontal arrangement. The main image is located at the top of the drawing on the left (if there are three projections) or close to the center (in the absence of a side projection).
5. Determine the location of the remaining images (side view, top view, sections, sections). Kinds the details they are formed by projecting it onto three or two mutually perpendicular planes (Monge method). In this case, the part must be positioned in such a way that the set or all of its elements are projected without distortion. If any of these species is informationally redundant, do not execute it. The drawing should have only those images that are needed.
6. Select the cuts and sections to be performed. Their difference from each other is that the section also shows what is behind the secant plane, while the section displays only what is located in the plane itself. The cutting plane can be stepped and broken.
7. Proceed at ease to drawing. When drawing the lines, follow GOST 2.303-68, which defines kinds lines and their parameters. Place the images from each other at such a distance so that there is enough space for dimensioning. If the cut planes pass along the monolith the details , stroke the sections with lines running at an angle of 45 °. If the hatching lines coincide with the main lines of the image, you can draw them at an angle of 30 ° or 60 °.
8. Draw dimension lines and dimension. In doing so, follow the following rules. The distance from the first dimension line to the image silhouette should be at least 10 mm, the distance between adjacent dimension lines should be at least 7 mm. Arrows must have a length of about 5 mm. The numbers should be written in accordance with GOST 2.304-68, their height should be equal to 3.5-5 mm. Place the numbers closer to the middle of the dimension line (but not on the image axis) with some offset relative to the numbers affixed to adjacent dimension lines.
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Performing an accurate drawing repeatedly requires a large investment of time. Consequently, in case of urgent need to make some part more often not a drawing is made, but a sketch. It is performed quite rapidly and without the use of drawing tools. In this case, there are a number of requirements that a sketch must meet.
You will need
- - detail;
- - paper;
- - a pencil;
- - measuring tools.
Instruction manual
1. The sketch must be accurate. According to it, the person who will make a copy of the part should make an idea of \u200b\u200bboth the appearance of the product and its design features. Therefore, before each, observe the subject observantly. Determine the relationship between the various parameters. See if there are holes where they are, their size and the ratio of diameter to the total size of the product.
2. Determine what the main view will be and how accurate it is about the detail. The number of projections depends on this. There may be 2, 3 and more. On how many projections you need, their location on the sheet depends. You need to proceed from how difficult the product will be.
3. Choose a scale. It should be such that the master could easily make out even the smallest details.
4. Start sketching with center and center lines. In the drawings, they are usually indicated by a dashed line with dots between the strokes. Such lines indicate the middle of the part, the center of the hole, etc. They remain on the working drawings.
5. Draw the external silhouettes of the part. They are indicated by a thick constant line. Be careful to convey the aspect ratio correctly. Put internal (noticeable) outlines.
6. Make cuts. This is done the same way as in any other drawing. The solid surface is shaded with oblique lines, the voids remain unfilled.
7. Draw dimension lines. Parallel vertical or horizontal strokes extend from the points the distance between which you want to indicate. Between them, draw a straight line with arrows at the ends.
8. Measure the part. Indicate the length, width, hole diameters and other dimensions needed for accurate work. Write the dimensions on the sketch. If necessary, put signs indicating the methods and qualifications of processing different surfaces of the product.
9. The final stage of work is filling out the stamp. Enter product information in it. In technical universities and design organizations, there are standards for filling stamps. If you are sketching for yourself, then you can primitively indicate what kind of part it is, the material from which it is made. All other data, the one who will make the part, should see in your sketch.
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The drawing serves to ensure that the one who will grind the part or build a house, can get the most accurate picture of the appearance of the object, its structure, the ratio of parts, methods of surface treatment. One projection for this, as usual, is unsatisfactory. In educational drawings, three types are usually performed - the main one, on the left and on the top. For objects of difficult shape, the right and back views are also used.
You will need
- - detail;
- - measuring instruments;
- - drawing instruments;
- - a computer with AutoCAD.
Instruction manual
1. The sequence of drawing on the sheet of Whatman paper and in AutoCAD is approximately identical. Take a look at the part first. Determine which perspective will give the most accurate picture of the form and functional features. This projection will become its main view.
2. See if your part looks identical if you look at it on the right and left. Not only the number of projections depends on this, but also their location on the sheet. The left view is located to the right of the main one, and the right view is, respectively, to the left. Moreover, in a flat projection they will look as if they are at ease in front of the observer's eyes, that is, without perspective control.
3. The methods for constructing a drawing are identical for all projections. Mentally position the object in the system of planes onto which you will project it. Analyze the shape of the subject. See if it can be divided into more primitive parts. Answer the question in the form of which body it is allowed to completely enter your object entirely or any fragment of it. Imagine how the individual parts look in the orthogonal projection. The plane onto which the object is projected when constructing the left view is on the right side of the object.
4. Measure the part. Remove the main parameters, set the ratio between the whole object and its individual parts. Select the scale and draw the main view.
5. Choose a construction method. There are two of them. To complete the drawing with the removal method, first apply the general silhouettes of the object, to the one that you look to the left or right. After this, gradually begin to remove the volumes, drawing recesses, the silhouettes of the holes, etc. When receiving the increment, one element is first drawn, and then the rest are slowly added to it. The choice of method depends primarily on the difficulty of projection. If the part when looking at it from the left or from the right represents a clearly expressed geometric figure with a small number of deviations from the severe form, it is more convenient to use the removal technique. If there are a lot of fragments, but the part itself cannot be entered into any figure, it is better to step by step attach the elements to each other. The difficulty of projections of one and the same part can be different; consequently, methods can be changed.
6. In any case, start building a side view from the bottom and top lines. They must be on the same tier as the corresponding lines of the main view. This will provide projection communication. After this, apply the general silhouettes of the part or its first fragment. Observe the aspect ratio.
7. Having drawn the general silhouettes of the side view, apply axial lines, hatching, etc. Put dimensions on it. Signing a projection is not required invariably. If all types of parts are located on one sheet, then only the rear view is signed. The location of the remaining projections is determined by the standards. If the drawing is done on several sheets and one or both side views are not on the sheet on which the main one is necessary to sign them.
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Helpful advice
When constructing a side view in AutoCAD or another drawing program, combining the upper and lower lines of the main and side views at the first stage is not rigorous. The drawing is allowed to be executed in fragments, and tiers can be combined when you begin to prepare it for printing.
\u003e\u003e Drawing: Views. The number of views in the drawings
You already know that projection drawing images are called projections. Images used in technical drawings are called views.
View- This is an image of the visible part of the surface of the object facing the observer. The standard establishes six main types that are obtained when projecting an object placed inside a cube on all its faces (Fig. 130). Six faces of a hollow cube unfold to align with the frontal plane of the projections (Fig. 131).
The following species names are established:
1.Front view - the main view (located on the site of the frontal projection).
2. The top view (under the main view) is placed on the site of the horizontal projection.
3. View to the left (located to the right of the main view).
4. View to the right (placed to the left of the main view).
5. Bottom view (located above the main view).
6. Rear view (placed to the right of the left view).
The names of the species in the drawings do not label. As the main view, the image taken on the rear face of the cube, which corresponds to the frontal plane of projections, is taken.
The object is located relative to the frontal plane of projections so that the image on it gives the most complete picture of the shape and size of the object.
The number of views in the drawing should be selected as minimal, but sufficient to understand the shape of the depicted object. In views, it is allowed to show the necessary invisible parts of the surface of the object using dashed lines (Fig. 132).
In the drawing, the distance between the views is chosen arbitrarily, but in such a way that it was possible to apply dimensions. The drawings are not allowed to affix the same size twice, as this clutters the drawing, makes it difficult to read and use in work. Views, as well as projections, are located in projection communication.
When building drawings, sometimes only part of the view is performed. An image of a narrowly limited surface area of \u200b\u200ba part is called a local view. Local species are limited by the cliff line (Fig. 133). In fig. 133 local view is located in a projection connection. In this case, it is not indicated. In the front view, the arrow shows the direction of view.
If the local view is not located in a projection connection, then in the view it is indicated by an arrow and a letter of the Russian alphabet, and the image of the local view is inscribed with the same letter (Fig. 134).
Local species are allowed to affix dimensions.
Questions and Tasks
1. Define the concept of “view”.
2. How are the views in the drawings?
3. What are the images shown in Fig. 135, 136.
4. What does the dashed line in the left view mean (Fig. 136)?
5. Why is a drawing the main graphic document in production?
6. From the visual image of the part (Fig. 137), find the corresponding main view and top view. Write the answer in the workbook.
7. In fig. 138 arrows A, B, C show projection directions. Select the projection direction that should correspond to the main view of the part.
8. Determine how many images are needed to identify the shape of the parts (Fig. 139). Explain which characters you intend to use to reduce the number of species. Give the answer in writing.
N.A. Gordeenko, V.V. Stepakova - Drawing., Grade 9
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