It is a necessary step to break bags for bagged domestic waste before crushing it. This thesis carried out kinematic analysis for Whitworth mechanism, and put forward the requirements of shape of tool on account of the problem that materials (garbage) winded tools, In addition, it briefly discussed the design of avoidance device by Theory of Inventive Problem Solving (TRIZ). Preface Domestic waste refers to the solid waste generated in people’s daily lives. In recent years, with further urbanization, and the growth of population, domestic waste has been in sharp increase, so rational treatment of garbage has become a national sustainable development strategies related to the important issue. The main methods of waste disposal at this stage are landfilling, composting, incineration, of which landfilling is the most important. The level of domestic waste processing has a great gap between at home and abroad. As the processing technology has been started in Europe and other developed countries, thus, it is relatively mature, and the sense of residents’ environmental protection is stronger, the difficulty of waste disposal is reduced, so that the problems of waste disposal have been solved better. The research of waste disposal in China began in the 1980’s,and waste is bagged in the main form of garbage collection at present. On grouping garbage is so complicated and the equipments used to dispose garbage are insufficient, which can not meet the standards of waste reduction, innocuity and reclamation required by the government. At present, the garbage crushing equipment used in China is prone to twist, less efficient, poorly noisy, and adapt to different waste. Besides, it is easily over-fragment the unbreakable material such as glasses and used batteries, causing second pollution. Consequently, to develop new equipment for bagged domestic waste is of top priority.