3. The mechanism shown is an overload safety device, which releases the load when it exceeds a predetermined value T. A metal pin S is inserted in a hole in the lower part of the mechanism and is acted upon by the upper half. When the force in the pin exceeds its strength it fails and the two halves rotate about pin A thus the rollers release the eye bolt. a) Choose materials for the device if it used indoors, in a factory hall, with relatively low humidity and it operates about 50 times a day on average. b) What are the loadings in the links DB and DC and in the pin S? c) Determine the maximum load T which can be lifted if the pin fails when the force in it reaches 800N. d) Calculate the force at the pin joint A when the force in pin S is 800N. Hints a) The device is used indoor with low humidity, thus low or medium carbon steel can be used, provided that the dimensional calculations of the parts do not result in very large parts. If that is the case, alloyed steel heat treated is an option. As a note, do not always chose the strongest material available; take into account what is given in the problem including where the device is operating, in which environment, how frequent is operated, how expensive the device can be. b) Separate joint D and write equations of equilibrium, taking into account that the forces in links DB and DC are equal. c) Separate one of the plates, e.g. ABE; take the force at E equal to T/2 and the force at S equal to 800N; write an equation of balance of moments about A to find T d) For the same jaw write equations of balance of forces to find the reaction at A. 4. A typical diesel main journal bearing has the following characteristics: R=0.045m,L=0.04m,c=0.000045m,=0.7,U1=12.7m/s(2700rpm). The oil used is SAE30 and the working temperature is 82C. (use the charts bellow) Find load carried, flow required to prevent starvation, and the friction coefficient