Serra circular de bancada: proposta de um sistema de segurança

Abstract

The Statistical Yearbook of Social Safety Insurance (2013) published the registry of typical labor accidents presenting that the most affected parts of the body were injuries and fractures on wrists and hands, together totaling 16.5% of the accidents recorded in Brazil, a recurring fact since 2007. In this sense, the aim of this research is to propose a safety system in order to protect the hands of circular bench saw operators. For this, a literature review on wood use on civil construction was carried out, legal and cultural aspects of labor safety and product development were also studied. In this research we used the structured methodology of product development idealized by the authors Ulrich and Eppinger with some adjustments, following the steps of planning and developing product. In the planning phase we developed a checklist of safety conditions in the circular saw operation in order to identify market opportunities and also to plan the product. In the product development phase we identified the consumer’s (carpenters) requirements of those who operates circular saws on civil construction in the city of Juiz de Fora (MG). With the responses obtained, we defined the specifications of the product, enabling concepts creation, as well as ranking and choosing the best concept to be developed. A safety system prototype was designed, in which was installed an infrared presence sensor in the protective hood along with a break that stop the saw motor, which were interconnected by contactors. In the system test we used a tachometer and a digital oscilloscope for data acquisition. The test simulated the operator’s hand approach in the presence sensor detection zone. The results showed that the shorter time for stopping the whole system was 100 milliseconds. We use this time to calculate the safety distance for placing the presence sensor. We concluded that it is necessary to innovate the circular bench saw with an efficient and effective safety system to increase the operators safety. It was also concluded that the methodology adopted, for configuring a generic model, allowed its own adaptation to the product development proposed by this academic research, providing a starting point for continuous improvements.