tailieunhanh - Threading Technologies Part 1

Tham khảo tài liệu 'threading technologies part 1', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 5 Threading Technologies But I grow old always learning many things SOLON 640 - 558 BC Plutarch Solon xxxi 182 Chapter 5 Threads An Introduction The originator of the first thread was Archimedes 287-212 BC although the first modern-day thread can be credited to the Engineer and inventor Joseph Whitworth in 1841 where he developed the Standards for today s screw thread systems. Whitworth s 55 included angled V-form thread became widely established enabling thread-locking and unlocking precision parts and of sub-assemblies - paving the way to the build-up of precise and accurate modern-day equipment and instruments. Standardisation of Imperial thread forms in the USA Canada UK and elsewhere allowed for the interchangeablity of parts to become a reality. Around this time both in France and Germany metric threads were in use but it took until 1957 before both the common 60 included angled ISO M-thread and Unified thread profiles to become widely accepted and established Fig. 95 . Along with these and other various V-form threads that have been developed Fig. 95i they include quick-release threads such as the Buttress thread this being a modified form of square thread along with the 29 included angled truncated Acme form which is a hybrid of a V-form and Square thread. Tapered gas pipe and petroleum-type threads were developed to give a mechanical sealing of the fluid or gas medium with many other types including multi-start threads that are now in use throughout the world. V-form screw threads are based upon a triangle Fig. 95 - top diagram which has a truncated crest and root with the root either having a flat as depicted or a more likely a radius1 - depending upon the specification. If screw threads have an identical pitch2 but different diameters it follows that they would have dissimilar lead angles. Usually threads have just one start where the pitch and the lead are identical - more will be mentioned on multi-start threads later in this 1 Root radius1 is .