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Văn bản hướng dẫn thiết kế máy P11

Screwed Joints 1. Introduction. 2. Advantages and Disadvantages of Screwed Joints. 3. Important Terms used in Screw Threads. 4. Forms of Screw Threads. 5. Location of Screwed Joints. 6. Common Types of Screw Fastenings. 7. Locking Devices. 8. Designation of Screw Threads. 9. Standard Dimensions of Screw Threads. 10. Stresses in Screwed Fastening due to Static Loading. 11. Initial Stresses due to Screwing Up Forces. 12. Stresses due to External Forces. 13. Stress due to Combined Forces. 14. Design of Cylinder Covers. 15. Boiler Stays. 16. Bolts of Uniform Strength. 17. Design of a Nut. 18. Bolted Joints under Eccentric Loading | CONTENTS C H A P T E R 11 Screwed Joints 1. Introduction. 2. Advantages and Disadvantages of Screwed Joints. 3. Important Terms used in Screw Threads. 4. Forms of Screw Threads. 5. Location of Screwed Joints. 6. Common Types of Screw Fastenings. 7. Locking Devices. 8. Designation of Screw Threads. 9. Standard Dimensions of Screw Threads. 10. Stresses in Screwed Fastening due to Static Loading. 11. Initial Stresses due to Screwing Up Forces. 12. Stresses due to External Forces. 13. Stress due to Combined Forces. 14. Design of Cylinder Covers. 15. Boiler Stays. 16. Bolts of Uniform Strength. 17. Design of a Nut. 18. Bolted Joints under Eccentric Loading. 19. Eccentric Load Acting Parallel to the Axis of Bolts. 20. Eccentric Load Acting Perpendicular to the Axis of Bolts. 21. Eccentric Load on a Bracket with Circular Base. 22. Eccentric Load Acting in the Plane Containing the Bolts. 11.1 Introduction A screw thread is formed by cutting a continuous helical groove on a cylindrical surface. A screw made by cutting a single helical groove on the cylinder is known as single threaded or single-start screw and if a second thread is cut in the space between the grooves of the first a double threaded or double-start screw is formed. Similarly triple and quadruple i.e. multiple-start threads may be formed. The helical grooves may be cut either right hand or left hand. A screwed joint is mainly composed of two elements i.e. a bolt and nut. The screwed joints are widely used where the machine parts are required to be readily connected or disconnected without damage to the machine or the fastening. This may be for the purpose of holding or adjustment in assembly or service inspection repair or replacement or it may be for the manufacturing or assembly reasons. 377 CONTENTS 378 A Textbook of Machine Design The parts may be rigidly connected or provisions may be made for predetermined relative motion. 11.2 Advantages and Disadvantages of Screwed Following are the advantages and .