механики 3 курс. Перевод текстов по специальности
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MeasurementThe size and shape of all machine parts should be in accordance with the corresponding drawing. The produced parts should be checked by means of measurement, which generally involves comparison either with some accepted standard or with a matingpart. The significance of any measurement is determined by the degree of which the parts may be measured. Depending on measurements different measuring tools can be used such as rules, slide gauges, vernier calipers, depth gauges, dial indicators, micrometers, clearancegauges, inside and outside calipers, plug gauges, bevels, universal protractors,etc. Measuring toolsWhen accurate measurement of the part is required, the vernier calipers, micrometers and slide gauges are used. When it is not so important to have an accurate measurement of the part, metal rules, inside calipers and outside calipers will do. Steel rulesserver for determining the length and sometimes the depth of the part to be measured. Steel rules are graduated in millimeters, but in the USA and England they are graduated in thirty-seconds and sixty-fourths of an inch. The outside calipersare used for determining the internal diameters of the part. Its construction is almost similar to that of the outside caliper measurements of the part. The outside and inside caliper measurements may be read by placing the legs of the calipers on a rule and placing one leg and the end of the rule against a flat surface . Vernier caliperscan be used for measuring both external sizes of a part. By using vernier calipers measurements up to 001 may be determined. Vernier calipers consist of a primarysteel scaleand four jaws. Jaws are integralwith the scale. Jawsattached to the frame slidingalong the scale. The frame may be clamped on the scale in any position by means of an adjusting screw. External surfaces may be measured with jaws,while internal surfaces are measured with jaws. Тhe depth of recesses is measured with a depth rod. A vernieron the frame serves for measuring fractional parts of a millimeter. The micrometeris an instrument for precise measurement of length and thickness of a part to one ten thousandth of an inch. The principle of operation is similar to that of vernire calipers. A graduated thimble serves as the primary scale. The scale on the barrel of the micrometer is used for the vernier reading. The part to be measured is placed between the anvil and micrometer screw, which is called a “movable spindle”. By rotating the thimble, the spindle is removed or approached to the anvil. By rotating the ratchet thimblethe spindle is moved and thus the partis pressed to the anvil. Thereupon the rotation of the ratchet thimble is discontinued, the micrometer opening is fixed by the lock nutand the reading is taken. The micrometer reading is the sum total of the barrel divisions, the thimble divisions with respect to the axial line on the barrel, and the vernier reading. The dial indicator is a gauge with a graduated dial and an indicator pointer connected to a test point by a system of levers. Any movement of the test point is magnified by the indicator pointer. The dial indicator is used to check the shape of a part, the precision of its machining, as well as for checking the accuracy of cuttingmachines. Thread plug gauges or internal gauges, being of “go” and “no-go” type, are generally used for testing threads or tapped holes. Depth gaugesare used for measuring the depth of grooves and holes. Their principle of operation is similar to that of vernier calipers. A primary scale sliding in a frame may be locked in any position by a screw. The depth of a groove or a hole is measured by means of the primary scale and a vernier. Conical surfaces are measured with control gauges. The universal angle gauge consists of a base with a primary scale attached to the base. A quadrantwith a vernier may be moved along the arc of the base. A triangle may be attached to the quadrant by means of a holder. In its turn a detachable rule is attached to the triangle. The triangle and the detachable rule can be moved along the face of the quadrant. Angles can be measured within the range of 0 to 320 by means of the universal angle gauge.
Drawing, to measure, to involve, mating part, accuracy, slide gauges, vernier calipers, depth gauges, clearance gauges, micrometer, inside calipers, to graduate, internal diameters, to slide, adjusting screws, lock nut, tapped hole.
To measure, measuring, measurable, measured, measurement; to compare, comparative, compared, comparison; to signify, significant, significance; to depend, depending, dependence, dependent; to graduate, graduated, graduation; accuracy, accurate; precise, precision; general, generally, generation.
To place, inside, outside, to be similar, according to, with reference to.
1. Machine parts should be manufactured … their respective drawing. 2. … a micrometer it is possible to make measurements to a very high degree of accuracy. 3. Calipers are used for measurements to … 0.18 mm. 4. Measuring tools should be chosen … the machine part to be measured. 5. He micrometer is an instrument … measuring directly … thousandths, and estimating to quarter thousandths … an inch, … its range.
1.The principle involvedin the operation of the micrometer is explained in technical text-books. 2. The instruction on the use of this dial indicator is rather involved. 3. These drawings and their explanations are given to illustrate the principles involved. 4. Different kinds of instruments are used tomeasureholes of considerable depth. 5. A millimetre is a measureof length. 6. Steel plates usually varybesixteenths of an inch. 7. Bydividing the load required to break the specimen byits area, the ultimate tensile strength of material is obtained. 8. By accuracy of from is meant not only the exact duplication of irregular profiles, but also the accuracy of from embodied in squares, true cylinders, cones, etc.
A range of optical instruments for measuring surface finish, which are relatively inexpensive and of very robust design, and afford the advantage that they can readily be applied under both workshop and inspection-room conditions, is being produced by many plants. Known as optical devices, these units are of modern designs. The portable device is intended for checking the relatively coarse finishes produced by planing, turning, and milling.With this device a beam of light is directed past a straight, opaque edge, and through a lens at an angle of 45 to the work surface, and the line of intersection is observed at an angle of 90 to the light beam, through the eyepiece of the microscope. (b) Задайте три вопроса к тексту и ответьте на них.
Vernier calipers, to be used, to measure, external and internal sizes, a part, to consist of, steel scale, four jaws, two jaws, to be attached, the frame, to slide, the scale, the first two jaws, to be used, measuring external surfaces, the other two jaws, measuring internal surfaces, the depth, to be measured, a spindle.
1. What is a micrometer? 2. What is the function of the graduated thimble of the micrometer? 3. What is the scale on the micrometer barrel used for? 4. Where is the part placed for measurement? 5. How is the part pressed to the anvil and how is the micrometer reading taken? 10. Переведите текст. 5.3 C h i p p i n g M e t a l a n d Ch i p p i n g T o o l s Chipping is a process of removing metal from a work piece by means of a cutting instrument such as a chisel and a hammer. This process is used when a large piece of metal has to be remover from a work piece; this process is very labor-consuming and is applied only in cases when the work piece cannot be machined. Chipping is used in cases when it is necessary to cut off a piece of metal from sheet metal. Chipping of large parts is always done on an anvil but very often it is done on a bench vice. The work piece to be tooled is fixed during the cutting process in the bench vise. There are different tools used in metal-working shops for chipping stocks such as chisels. A chisel is a tool made of very hard steel, having a cutting edge is wedge-shaped. Under the effect of an external force applied to the wedge it cuts into the metal. The work of the wedge depends mainly on its cutting angle. The cutting edge of the chisel should be sharpened to an acute angle so as to provide for the best cutting ability, depending on the stock to be chipped. The harder the metal, the larger should be the cutting angle of the chisel and vice versa. An angle of about 70 is suitable for most work. The plan AO called the “front cutting face” or the “top face” is given a backward and sidewise slope for sliding the chips off the tool in a convenient direction while the plane OB is called the “back cutting face”. Being formed between the front and back cutting faces of the chisel the angle ABO is known as the lip angle. The angle BOC is the .clearance angle which is formed by the back cutting face of the chisel and the surface of the work to be treated. The slope in the direction of the chisel length in which the chip moves is called the “front rake” or “true rake”. The angle AOC formed by the lip angle and clearance angle is known as the: “cutting angle”. They are different types of chisels such as flat chisels, cape chisels, etc. Hammers are striking tools used in chipping, bending and other operations. Hammers are made of a solid piece of forger tool carbon steel, their weight depending on the stock to be removed.
To chip, chisel, stock, mechanical tools, blade, wedge, edge, cutting, angle, acute angle, clearance angle, cape chisel, front rake, to strike, to forge, solid
1. What is chipping? 2. What instruments are used in chipping? 3. What is a chisel? What types of chisels do you know? 4. What does the work of a chisel depend on? 5. What does the angle of the cutting edge of a chisel depend on? 6. Why is the top face of a chisel given a certain slope? 7. What is the front race? 8. What plane is called the “front cutting face”? 9. What plane is called the “back cutting face”? 10. What is the clearance angle, the lip angle and the cutting angle? 3. Заполните пропуски предлогами by, from, in, of, on: 1.Chisels are used … removing stock … works. 2. Chisels are usually made … a high grade steel. 3. The cutting edge … a chisel is … a chisel depends … the strength … a stock to be chipped. 5. Stock are chipped … means … a chisel and a hammer. 4. Подберите антонимы к следующим словам. Hard, large, suitable, convenient, backward, long 5. Переделайте данные прилагательные в наречия и переведите на русский язык. Different , hard, main, external, large, convenient 6. Переделайте следующие предложения, используя инфинитивные конструкции, и переведите их на русский язык. Например: The chisels which are to be used for chipping metals are made of high grade steel. The chisels to be used for chipping metals are made of high grade steel. 1. Different types of chisels are made of a good grade chisels steel which has to be forged annealed, and then hardened and tempered. 2. Chisels which must be applied for chipping metal stocks are made of hard steel. 3. Working a metal to a desired shape by forging produces the best combination of physical characteristics for parts which will be highly stressed. 4. An auxiliary equipment which will be used together with the forging hammer must withstand the vibration or impact of the forging blows. 5. The weight of hammers depends on the stock which will be removed. 6. The work required to separate the stock will depend upon the material is to be machined and the separation area. 7. Переведите следующие предложения, обращая внимание на выделенные курсивом слова. 1. The work piece to be tooled is fixed during the chipping process in the bench vice. 2. A chisel a tool made of very hard steel. 3. A chisel has a cutting edge at one end of the blade. 4. Тhe cutting edge of a chisel is wedge-shaped. 5. Тhe angle between the two edges of tool in the plane of the true rake is called the “lip angle” 8. Используя данные слова и выражения, дайте описание рисунка. A chisel, to be tool of very hard steel, to have a cutting edge, to be wedge-shaped, to be under the effect of an external force, to cut into metal, the work of the wedge, to depend on the cutting angle, to be sharpened to an acute angle, to provide the cutting conditions. 9. Переведите текст. Приложение А Краткий справочник по теории и практике перевода РАБОТА СО СЛОВАРЕМ Чтобы быстро находить нужное слово в словаре необходимо:
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