Design of Six-Link Folding Mechanisms for Classroom Table and Chair Set
碩士 === 國立臺灣科技大學 === 機械工程系 === 100 === This thesis deals with the design of a foldable classroom table and chair unit. The unfolded configuration of the mechanism would consist of a table, a seat with backrest and four legs, and an under seat rack as storage compartment. By searching related previous...
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| Format: | Others |
| Language: | zh-TW |
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2012
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| Online Access: | http://ndltd.ncl.edu.tw/handle/99389383043643577233 |
| Summary: | 碩士 === 國立臺灣科技大學 === 機械工程系 === 100 === This thesis deals with the design of a foldable classroom table and chair unit. The unfolded configuration of the mechanism would consist of a table, a seat with backrest and four legs, and an under seat rack as storage compartment. By searching related previous works and available patents, it is found that most of the mechanisms are not only too complicated but also give only limited storage spaces. Therefore in this work six-bar linkages are adopted as the base mechanism and optimization of the storage space is emphasized in the design considerations. Possible kinematic structures of the mechanisms are first synthesized based on the creative mechanism design methodology. Three conditions to allow the links of a four-bar linkage to fold into a straight line are then specified for obtaining a scalar constraint equation imposed on the link lengths of the synthesized mechanisms. By using this equation together with the vector loop equation of the mechanism at the fully unfolded configuration, a general analytical method is developed for two points dimensional synthesis and four distinct linkages which satisfy all of the design criteria are obtained. Pro/Engineer is then used for constructing the solid models of the mechanisms and for stress analysis to determine the best location of the fixture block which holds the linkage at the unfolded configuration. In addition, the optimal dimensions of the four linkages which would give the maximum storage space are investigated analytically. A scale model of the one with the best performance is fabricated to verify the proposed methods.
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