Force Analysis with Friction:

The reciprocating engine mechanism is illustrated in Fig 6(i). The sliders enclose impending motion towards the right. Consider the friction angle be φ. It is needed to measure the couple on the link 2 for static equilibrium. Figure 8(i) illustrate free body diagram of the link 4 that is a slider. The force diagram has been drawn in Figure 8(ii). An appropriate scale might be assumed and know force P may be poltted. For other two forces F₁₄ & F₃₄ only directions are known. Lines may be drawn from two extremities parallel to the direction of these forces. They shall meet at a point. From this triangle of forces the magnitude of F₁₄ & F₃₄ will be known. On the connecting rod AB the forces will be acting along the friction axis that has been discussed in Section 13.2.1. After knowing F₃₄, F₂₃ must be known that is equal and opposition to F₃₂ knowledge of which will provide magnitude of the couple.

(i)                                                     (ii)

   (iii)                                       (iv)

  Figure (8)