Practical work 18 reading assembly drawings. Summary of a drawing lesson on the topic "reading assembly drawings"

Figures 244-248 show assembly drawings of five different products, and Figure 249 shows visual representations of six products. Some of them are given in figures 244-248, but not all. Determine which visual images, indicated by letters, show exactly those products that are also contained in the assembly drawings. Write to workbook, which of the visual images shows which product. Recording form: “On the visual image A is drawn...” (take the name of the product from the assembly drawing).

Do not forget that not all assembly drawings include visual images.

Read the assembly drawings indicated by the teacher in Figures 244-248, following the sequence given in 35. Answer questions (including additional ones) in writing.

Additional questions regarding assembly drawings

Rice. 244. Reading drawing

To Figure 244

Why is detail 37 not shaded?
Why is item 2 cross-shaded?

Rice. 245. Reading drawing

To Figure 245

Is image B-B a section or a section?
What is it given for?

Rice. 246. Reading drawing

To Figure 246

Why was incision A - A made?
What is the shape of part 5?

Rice. 247. Reading drawing

To Figure 247

Why is item 3 cross-shaded?
Why does the shading of parts 1 and 2 have different direction?

Rice. 248. Reading drawing

To Figure 248

Which line represents the workpiece being processed?
Why is the special screw (part 3) not shaded on section A - A, but shaded on section B - B?

Complete technical drawings of one or two parts suggested by the teacher. An appropriate visual image will help you get the job done.

Rice. 249 Exercise task

Purpose and arrangement of assembly units included in practical work No. 19.

The handle (Fig. 244) is attached to the door leaf using screws, for which holes are provided on the base (part 1). The handle consists of a base and a handle connected with a screw (part 3).
Puller (Fig. 245) - a device for removing pulleys, bearings and other parts from shafts.

The main parts of the puller: the rocker arm (part 1), on which the grips (part 3) and the pressure screw (part 2) are attached. A limiter (item 4) secured with screws (item 5) prevents the grip from slipping off the rocker arm.

The device to be dismantled is installed on the protrusions of the grippers. The removal of parts is carried out by rotating the pressure screw, into the hole of which a rod (lever) is inserted for this purpose.

Device (Fig. 246) - a jig is used when drilling holes on tiles, in this case having a rectangular protrusion.

The base (part 1) of the conductor is connected to the plate (part 2) with pins (part 5) and screws (part 6). There is a guide bushing (part 3) in the top of the plate, and a handle (part 4) is screwed into the side.

When drilling a hole, the protrusion of the workpiece is inserted into a rectangular hole in the base, the drill is guided through the sleeve from above.

The roller (Fig. 247) serves as a support for moving heavy objects. It is used in sets of several pieces. Roller (part 2) with rubber tire(part. 3) are attached to the base (part. /) using a bolt (part. 4) and a nut (part. 5) with a washer (part. c).
The invoice jig (Fig. 248) is used when drilling, in this case, two holes with a diameter of 4.2 in the workpiece. The screw (part 3) of the jig is attached to the drilling machine table. After installing the workpiece, a plate (part 1) is placed on it, which is secured with a hook (part 4). The hook provides easy and quick fastening of the conductor plate.

§ 37. The concept of detailing

Products consisting of several parts are assembled according to assembly drawings. But first, the parts are made, and for this it is necessary to provide their production with drawings. The process of drawing up drawings of parts based on drawings of products consisting of several parts is called detailing.

Rice. 250. Assembly drawing and visual representation of the stop

The essence of the detailing process will be clear from a comparison of Figures 250 and 251. The stop, the drawing and visual image of which are shown in Figure 250, is mentally divided into individual parts (Figure 251, a). Figure 251, b shows drawings of two parts; as a rule, they contain various instructions, including those related to the manufacturing technology of the part. These designations are not given here. They are studied during workshops on mechanical engineering drawing.

Rice. 251. Details of the stop: a - visual image; 6 - drawing of the flying “hull”; c - drawing of the “cracker” part

Read the product drawing in the sequence given in § 35, turning special attention on the shape of parts, their purpose and interaction.
Mentally disassemble the product into individual parts.
Highlight standardized parts that do not have drawings.
Determine the number of images needed when drawing each part. However, you cannot copy it from the drawing to be detailed. The screw (part 3), for example, in Figure 250 is presented in three types. In the drawing of this part, one view is sufficient. Conversely, the stand (detail 1) in Figure 232 is shown in three views and a section, although the drawing of this part must contain at least five images.
Find the mating surfaces of parts, i.e. surfaces that interact with the surfaces of other parts. These include, for example, the surfaces of the pin and the holes for it (Fig. 246).

For mating surfaces, the dimensions must be coordinated. This means that, for example, the outer diameters of the bushing and the hole into which it is pressed should be the same in size (Fig. 248).

When detailing, especially when drawing dimensions, you need to use reference books. So. The dimensions of the keyways should be selected and applied in accordance with the recommendations given in section 33.1; dimensions of threaded products in accordance with the recommendations given in sections 31.3 and 32.2. Finally, it is advisable to use the reference book when something is forgotten or encountered for the first time. For example, in the specification of the assembly drawing there was the designation: “Cotter pin 1.5x15 GOST 397-79.” You don't know what shape the part is or what the numbers on the entry mean. From the reference book we learn that the part has the shape shown in Figure 252. The designation should be understood as follows: cotter pin for holes with a diameter of d=1.5 mm, cotter pin length 15 mm.

Rice. 252. Cotter pin

Using reference books when reading and drawing up drawings, including during tests, relieves memory, allows you to get more new information, speeds up work.

When performing detailing, you need to draw each detail on a separate sheet, the format of which depends on the selected scale. Most of the data for the title block is taken from the specification of the assembly drawing.

Let's look at an example of detailing. Figure 253 shows a visual representation of the crank. Figure 254 shows its drawing. The crank transmits motion from the connecting rod to the shaft, converting the translational movement of the piston into the rotational movement of the shaft (see diagram in Fig. 255). It is an eccentrically located finger (item 2), connected through a shoulder (item 1) to a shaft (item 3), to which rotational motion is imparted. A connecting rod coming from the piston is pivotally connected to the crank pin.

Rice. 253. Crank

After reading the drawing (Fig. 254), we establish according to the specification that it shows a crank. The main view and section are given. Main view contains a local incision. Detail image 3 also contains a local section.

Fig. 254. Assembly drawing of the crank

Part 6 - the bolt has a head in the form of a hexagonal prism. The main dimensions of the bolt: MB thread, rod length 25 mm. We learn this from the specification. Knowing the standard number, you can determine the “key size” (it is 10 mm), head height (4 mm) and other dimensions.

Rice. 255. Scheme of crank operation

Part 5 - nut with M6 thread has the shape of a hexagonal prism.

Part 2 is called “finger”. It consists of three cylinders and a truncated cone. The conical end of part 2 is riveted, which ensures the immobility of the connection with part 1.

The key (item 4) is prismatic. The height and width of the key are 6 mm, length 14 mm. We also learn this from the specification.

The “arm” part has four holes: one conical, the second cylindrical for a shaft with a diameter of 21 mm, and two also cylindrical for a MB bolt. The bolt and nut serve to tighten the arms of the arm, which clamps the shaft. Parts 1 and 3 are connected by a parallel key.

Sizes diameter 16 and 24 are connecting, size 160 is overall.

There is no need to draw up drawings for parts 4,5 and 6, since they are standardized.

Thus, the drawing is read. The product is mentally disassembled into individual parts. Those for which you need to draw up drawings are highlighted, determining the required number of images, the position for the main view, marking the mating surfaces and selecting the scale.

Figure 256 shows a drawing of part 2 - finger. In the drawing, where it is presented in conjunction with other parts, the finger is shown in two images, and here in one, since the shape of the finger is completely revealed by one view.

Rice. 256. Drawing of part 2 crank

Figure 257 shows a drawing of the shoulder. Dimensions that were not in Figure 254 are determined using an angular scale (see instructions for work No. 20). The keyway dimensions of 6 and 2.8 mm are taken from the reference table (see § 33).

Rice. 257. Drawing of part 1 of the crank

The dimensions of the mating surfaces (for diameters 16 and 21) are mutually consistent.

Drawing. Lesson 28 (second year of study, 9th grade). 1. Topic “Reading assembly drawings. Practical work 8" 2. Gordovaya Nadezhda Semenovna, drawing teacher at Vydrinskaya secondary school secondary school Kabansky district, Republic of Buryatia 3. Subject: drawing. 4.Presentation Microsoft PowerPoint 5.Microsoft PowerPoint, Internet Explorer, own developments, didactic material, textbook by I.A. Roitman, Ya.V. Vladimirov, demonstration models, tables. 6.During drawing lessons 7.For 9th grade students 8.Volume: 14 slides, 515 Kb.

Express survey 1. What is shown on assembly drawings: an image of a part or an assembly unit? Assembly unit 2. What are assembly drawings for? To assemble an assembly unit from individual parts 3. Are sections and sections used when making assembly drawings? Apply 4.Where on the drawings are the names of the parts included in the product indicated? The table contains specifications 5. Is it necessary to include all the dimensions of the parts included in the product on the assembly drawings? No. Only dimensional, connecting, installation 6. What do the numbers on the shelves of leader lines mean? Part numbers on the drawing 7. How to hatch three touching parts on assembly drawings? IN different sides, with a change in the distance between the hatching lines 8. How can a section show narrow cross-sectional areas, the width of which in the drawing is 2 mm or less? Shown in black 9. Remember what it means to “read the working drawing of a part”? Imagine its three-dimensional shape, dimensions, location of all its elements. Evaluation of results: (9, 8 correct answers – “5”, 6.7 correct answers – “4”, 4.5 correct answers – “3”)

Comparative and comparative characteristics: Working drawing Assembly drawing Made according to ESKD standards (formats, title block, lines, fonts, etc.) Images are used (views, sections, sections), conventions and simplifications An image of a part is given An image of an assembly unit is given Used for the manufacture of a part Serves for assembling a product from parts All dimensions are indicated Dimensional, connecting, installation Position numbers are indicated Availability of a table with data - specifications

Reading a drawing of a part means: using the flat images on the drawing of the part, imagine its three-dimensional shape, design, dimensions, location of all its elements. Read assembly drawing means: using flat images of an assembly unit, imagine its three-dimensional structure, the shape and dimensions of its individual parts, their location and connection, as well as the principle of operation of the product.

Procedure for reading assembly drawings. Find the product name. Determine which images (types, sections, sections) are given in the drawing. Using the specification, look at the images of each part and determine their geometric shape. Determine how the parts are connected to each other. Find other data given in the drawing (dimensions, technical requirements etc.).

Conclusion: Products are assembled using assembly drawings; in addition, using assembly drawings one gets acquainted with the design of products, their principle of operation, and also, using assembly drawings, products are adjusted during operation, installed (mounted) at the workplace, and the product is repaired.

Lesson developed by teacher

Gorlovka General Educational

wcolaI – II No. 35

Dushkina I. A.

Lesson #18 (No. 4 in topic No. 13 “Reading and detailing assembly drawings”)

Date…………

Class 9

Subject: practical work on the topic “Reading assembly drawings for

plan"

Lesson objectives:

Educational: test the knowledge, skills and abilities of students in reading assembly drawings according to the given plan, consolidate the skills of reading assembly drawings and writing notes in a drawing font.

Educational: promote diligence, accuracy, and work culture.

Developmental: promote further development memory, attention, eye; logical, analytical and spatial thinking.

Teaching aids, drawing tools, accessories and materials.

For the teacher:

textbook “Drawing.8 – 9kl.” edited by V.K. Sidorenko

educational tables containing images of assembly drawings of simple assembly units, writing a drawing font

didactic materials (cards - assignments) edited by E.A. Vasilenko

table "Reflection"

electronic version of tables, cards (if necessary equipment is available)

For students: A4 format, checkered, task cards, drawing cards

accessories and tools.

Lesson type: control and correction of knowledge, skills and abilities

Lesson progress

1. Organizational stage:

Greetings

Organizing the students' workplace, issuing task cards, drawing tools, accessories and materials from the office fund for work in this lesson. Checking readiness for the lesson.

Checking student attendance.

Teacher filling out a class log

Announcing the topic of the lesson.

2.Updating background knowledge and check homework.

The teacher visually checks homework completion

3. Motivation educational activities.

Today we are testing your knowledge, skills and abilities in reading assembly drawings, taking into account the learned conventions and simplifications that you received in previous classes and in self-preparation for practical work. I hope that this will allow me to successfully complete today’s practical work and begin studying the topic “Detailing Assembly Drawings” in the next lesson.

Declaring the goals and objectives of the lesson:

Today in class:

Students must independently read the assembly drawing according to the given plan.

Complete a technical drawing of the part specified in the task card

Identify deficiencies and gaps in knowledge to correct and fill them in home preparation to subsequent lessons

At the same time, we must be attentive, think, analyze, imagine and not waste time

Good luck in your work

4. Practical work. Formation of skills and abilities.

4.1. Issuance of individual cards - tasks 10 options (attached)

4.2. Answers to questions about the assignment, if any.

4.3. Independent work of students under the visual supervision of the teacher.

5. Summing up the lesson.

The teacher gives general characteristics educational activities in the classroom;

Collects works

Reflection: continue the sentence:

I didn't think that...

I will definitely…….

It seemed to me that…….

I didn't like it………

I think I will need………

6. Homework:

Repeat the material on the topic “Reading assembly drawings”

At the request of students, complete a creative task on the studied section (prepare an electronic presentation, make a crossword puzzle, rebus - optional)

Application

Option #1

Task 1.

Task 2.

Option No. 2