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Sổ tay tiêu chuẩn thiết kế máy P46

Tham khảo tài liệu 'sổ tay tiêu chuẩn thiết kế máy p46', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | CHAPTER 39 A THESAURUS OF MECHANISMS L. E. Torfason Profesor of Mechanical Engineering University of New Brunswick Fredericton Canada GLOSSARY OF SYMBOLS R Revolute pair or pin joint P Prismatic pair or sliding joint C Cylinder pair for joints that allow rotation and sliding along the cylinder axis G Spheric pair globe for ball joints SL Screw pair with lead L F Planar pair flat for a joint that maintains two planes in contact SUMMARY This chapter is intended to be used as an idea generator. Following the adage that a picture is worth 1000 words this chapter was assembled with millions of words in figures and virtually none using the alphabet. I have taken the liberty of varying dimensions to better show the principle of operation. You should not scale the figures but follow the regular synthesis procedure to determine the proper dimensions for the application in mind. In this chapter a new notation is used for the kinematic representation of joints or pairs in a linkage. Readers will note a difference in the style and character of the figures in this chapter. When this manuscript was received the illustrations all conceived and executed by Professor Torfason were seen to be original and unique. We asked for and received from the publishers special permission to reproduce them exactly as they were drawn Eds. 39.1 39.2 STANDARD HANDBOOK OF MACHINE DESIGN COLLATERAL READING L. J. Kamm Designing Cost-Efficient Mechanisms McGraw-Hill New York 1990. m FIGURE 39.1 Snap-action mechanisms. These mechanisms are bistable elements in machines. They are used in switches to quickly make and break electric circuits and for fastening items a Snap-action toggle switch b to h seven variations of snap-action switches i circuit breaker J to o spring clips. A THESAURUS OF MECHANISMS 39.3 FIGURE 39.2 Linear actuators. These are devices that cause a straight-line displacement between two machine elements a Lead screw worm gear with stationary nut c worm gear with stationary screw d .