22.1. Location of sections. According to their location in the drawing, sections are divided into extended and superimposed. Extracted parts are placed outside the contour of the image (see Fig. 170) anywhere in the drawing field, superimposed - directly on the views (see Fig. 171).
Rice. 170. Exposed sections
Extended sections are preferable, as they do not clutter the view with unnecessary lines.
Rice. 171. Superimposed symmetrical section
The contour of the extended section is outlined with a solid thick main line of the same thickness (s) as the line adopted for the visible contour of the image; the contour of the superimposed section is a solid thin line (from 1/3 to 1/2); Moreover, the outline of the view at the location of the superimposed section is not interrupted.
22.2. Designation of sections. To show where the cutting plane passes, it is designated.
If the section is extended, then, as a rule, an open line is drawn, two thick strokes (Fig. 170). Arrows indicate the direction of view. They are located at the outer ends of the open line. WITH outside the arrows apply the same capital letters Russian alphabet.
Above the section the same letters are written through a dash with a thin line below.
If the section is a symmetrical figure and is located on the continuation of the section line (dash-and-dash), then arrows and letters are not applied (see Fig. 170).
The superimposed section is usually not indicated (Fig. 171). Only in the case when it is an asymmetrical figure, open line strokes and arrows are drawn, but letters are not applied (Fig. 172).
Rice. 172. Designation of superimposed asymmetrical section
22.3. Features of making sections. For the most part, sections are made to the same scale as the image to which it relates, and the scale is indicated if it is changed.
In terms of construction and location, the section must correspond to the direction indicated by the arrows.
Figure 173 shows how, depending on the direction of view, the contour of a part element is located in a section. The groove in the section is located on the right, which means it is located in the front of the part.
Rice. 173. Aligning a section with the drawing plane
If the secant plane passes through the axis of the surface of revolution (cylindrical, conical or spherical) limiting the hole or recess, then their contour in the section is shown in full (Fig. 174).
Rice. 174. An example of a section in which the contour of a conical recess is shown in full
It is more convenient to plot some dimensions of part elements on sections.
Figure 175 shows the dimensions of a keyway on a section.
Rice. 175. Example of applying dimensions on a section
Graphic work No. 12. Sketch of a part with sections
Draw a sketch of the part on a sheet of A4 squared paper according to the teacher’s instructions from life or according to a visual image (Fig. 177). Reveal the cross-sectional shape of the part. Label it if necessary. Add dimensions.
Rice. 177. Assignments for graphic work No. 12
Explanations for the work. When constructing sections, follow the examples given in Figures 170, 171, 172, 174 and 175.
Graphic work№1
Drawing fonts
Purpose: to check the assimilation of knowledge on the topic “Drawing fonts”
Efremovskaya average comprehensive school
Educational area Technology
Subject Drawing
Completed
Student's name
Checked
Teacher's name
2013-2014 academic year
Graphic work№2
Dividing a circle into equal parts
Purpose: to check the assimilation of knowledge on the topic “Dividing a circle into equal parts”
I-variant – into 3 parts
Option II – 5 parts
ІІІ-option – for 6 parts
ІY-version – for 8 parts
Graphic work№ 5
Target
I-option
Roller Steel 45
Graphic work№ 5
Drawing of parts with sections
Option II
Target : check your knowledge on the topic “Sections”
Finger Steel 50
Graphic work№ 5
Drawing of parts with sections
ІІІ-option
Target: check your knowledge on the topic “Sections”
Draw a sketch of the part on a sheet of A4 paper using a visual image. Reveal the cross-sectional shape of the part. Label it if necessary. Add dimensions.
Roller Steel 45
Graphic work№ 5
Drawing of parts with sections
ІY-variant
Target : check your knowledge on the topic “Sections”
Draw a sketch of the part on a sheet of A4 paper using a visual image. Reveal the cross-sectional shape of the part. Label it if necessary. Add dimensions.
Axle Steel St.5
Graphic work№ 6
Drawing of parts with cuts
Purpose: to check the assimilation of knowledge on the topic “Cuts”
1st option
Draw a sketch of the part on a sheet of A4 paper using a visual image. Make a cut on the product
2nd option
Graphic work№ 7
Drawing threaded connections
Purpose: to check the assimilation of knowledge on the topic “Connections”
Content: Draw a drawing of the connection of two parts using threaded products. Option 1
Graphic work№ 8
Content: Execute. (Composition of the assembly unit:1 - sponge;2 - spring;3 - screw.) Option 1
Drawing of a part from life or according to an assembly drawing
Purpose: to check the assimilation of knowledge on the topic “Assembly drawing”
Executesketch of the part according to the assembly drawing. (Composition of the assembly unit:1 - rod;2 - frame;3 - lid.)
Option 2
Graphic work№ 8
Drawing of a part from life or according to an assembly drawing
Purpose: to check the assimilation of knowledge on the topic “Assembly drawing”
Executesketch of the part according to the assembly drawing. (Composition of the assembly unit:1 - flange;2 - a tube.)
Option 3
Graphic work№ 9
Part drawing according to sketch
Purpose: to check the assimilation of knowledge on the topic “Purpose and execution of sketches”
Contents: Draw one part Option 1
| Option 3 |
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Graphic work№ 10
Drawing of the plan and facade of the building
Purpose: to check the assimilation of knowledge on the topic “Elements of construction and topographical drawing”
This book is the main textbook on drawing, which corresponds to the current program approved by the Ministry of Education and Science of the Russian Federation.
In the textbook along with theoretical material included questions and tasks, graphic and practical work necessary to consolidate and repeat the material covered. The book is well illustrated.
How to work with drawing tools.
Straight lines are first drawn along the edge of a ruler or square without pressure with a hard, sharpened pencil, and then traced with a soft pencil or a medium-hard pencil. In this case, the pencil is slightly tilted in the direction of movement, as shown in Figure 15. Horizontal lines are drawn from left to right, vertical and oblique lines are drawn from bottom to top (see Figure 15, d, b, c).
To get clearer and even lines when tracing, the pencil can be drawn along these lines repeatedly in the opposite direction. When drawing vertical and inclined lines, the square is moved along the edge of the gauge or ruler from left to right, and when drawing horizontal lines - from top to bottom.
Techniques for constructing straight, obtuse and sharp corners are shown on the flyleaf at the end of the book. To draw circular arcs, the leg of the compass is placed in the center. The compass is rotated by the head with a large one and index fingers in the clockwise direction (Fig. 16). The short leg with a pencil insert and the compass needle in the working position should be parallel to each other. While rotating, the compass can be tilted forward slightly.
Content
Introduction
I. Technique for making drawings and rules for their design
1. Drawing tools, materials and accessories. Workplace organization
2. Rules for drawing drawings
II. Drawings in the rectangular projection system
3. Projection
4. Rectangular projection
5. Location of views in the drawing. Local species
III. Axonometric projections. Technical drawing
6. Obtaining axonometric projections
7. Construction of axonometric projections
8. Axonometric projections of objects with round surfaces
9. Technical drawing
IV. Reading and following drawings
10. Analysis geometric shape subject
11. Drawings and axonometric projections of geometric bodies
12. Projections of vertices, edges and faces of an object
13. The order of constructing images in drawings
14. Applying dimensions taking into account the shape of the object
15. Geometric constructions necessary when making drawings
16. Drawings of developments of surfaces of geometric bodies
17. Order of reading drawings of parts
V. Sketches
18. Sketching parts
19. Repetition of information about projection methods
VI. Sections and cuts
20. General information about sections and cuts
21. Purpose of sections
22. Rules for making sections
23. Purpose of cuts
24. Rules for making cuts
25. Connection of view and section
26. Thin walls and spokes in the section
27. Other information about cuts and sections
VII. Determining the required number of images
28. Selecting the number of images and the main image
29. Conventions and simplifications in drawings
VIII. Assembly drawings
30. General information about connections of parts
31. Image and designation of thread
32. Drawings of bolted and stud connections
33. Drawings of keyed and pin connections
34. General information about assembly drawings of products
35. Procedure for reading assembly drawings
36. Conventions and simplifications in assembly drawings
37. The concept of detailing
IX. Reading construction drawings
38. Main features of construction drawings
39. Conditional images on construction drawings
40. Procedure for reading construction drawings
Appendix 1. Varieties graphic images
Appendix 2. Note on computer technologies for performing graphic work.
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Sketches of assembly unit parts
Purpose of the lesson: study the rules for making assembly drawings; registration of assembly
drawings and specifications.
The student must:
The production of an assembly drawing is preceded by work on sketching each part included in the assembly unit, sketches on Standard products do not do.
When making sketches for assembly drawings Special attention should be applied to the contacting surfaces so that their sizes do not diverge.
To quickly and accurately draw up assembly drawings, you need to know the conventions and simplifications:
Control questions:
Assembly drawing detailing
Purpose of the task: gain skills in reading assembly drawings and drawing up working
drawings of parts according to assembly drawings.
The student must:
Instructions for performing the work:
Drawings of parts are made on separate sheets of standard format drawing paper. Standard parts are not subject to detailing. In one of the drawings of parts, in addition to orthogonal projections, an axonometric projection of the part is drawn.
Detailing is the development and execution of drawings of parts based on an assembly drawing. Using the description of the assembly unit and specification, read Assembly drawing, that is, find out the structure and operating principle of the assembly unit, what parts and in what quantity the assembly consists of, methods for connecting the parts to each other. To get a complete picture of the geometric shape of each part, you need to remember the projection connection, remember that each part in all images has the same independent shading. It is necessary to establish which images will be given in the drawing and determine the position of the planes for cuts and sections. It is recommended, first of all, to start drawing a working drawing of a part, having first completed a sketch of this part.
After reading the assembly drawing, you should:
1. Determine and select the number of types, cuts, sections for each part:
2. Position the part on the drawing according to its workpiece during processing, casting parts - according to their position in the product.
3. Determine the dimensions from the assembly drawing, the dimensions necessary to complete the drawing of parts.
4. redraw the details from the sketch to the drawing, choosing the sheet format in advance and thinking through the compositional arrangement of the image.
Fill in the title block
5. draw an assembly drawing on sheet A2, format it in accordance with GOST.
6. Fill out the specification
task options
Control questions:
1. what is detailing?
What is an assembly unit?
Lesson topic: graphic work No. 10 “Drawing of a part with sections”
Goals: teach the correct construction of a section
; nurturing cognitive interest in the subject, developing independence and accuracy; development of creative, abstract thinking.
Lesson type: combined
Teaching methods: visual, deductive, practical .
Equipment: drawing tools; notebook, textbook, differentiated task cards
During the classes
I. Organizational moment.
II. Checking homework.
What image is called a section?
What is the section used for?
How is the section selected?
III. Updating students' knowledge. Introduce students to the algorithm for constructing sections.
Write down the algorithm for constructing a section in a notebook:
Analysis of the geometric shape of a part
Selecting the location for introducing cutting planes.
Mental representation of cross-sectional figures and analysis of their graphic composition
Construction of section figures:
drawing center lines of the section figure;
constructing the general outline of a sectional figure;
clarification of the section figure, that is, construction of an image structural element, caught in the cutting plane;
hatching a section figure
Designation of cutting planes and section figures, stroke.
IV. Performance graphic task. Distribution of individual differentiated task cards. (application)
Checking the correctness of the task.
V. Lesson summary.
VII. Homework: complete the outline of the drawing
APPLICATION
1 difficulty level
Redraw main view and, perform section figures, which are indicated by letters.
1 option
Option 2
Difficulty level 2
required sections (Fig. 1).
2. Guided by the drawing (Fig. 2), find a correctly executed section.
1 option
Option 2
Difficulty level 3
1. Using axonometric images, make sketches of parts using
required sections (Fig. 1).
2. Guided by the drawing (Fig. 2), find the correctly executed
1 option
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