Technical Drawing 2, May/June 2015

Question 2

(2)        The figure above shows crank OQ which rotates in clockwise direction.  The rod PQ is connected to the crank at Q and slides through the slot R.

Plot, full size, the locus of point P when the crank makes one revolution.

Observation

Candidates were expected to:

  1. copy the given mechanism (crank OQ, Circle R25, Rod QP, Slot R, Centre lines);
  2. divide circle into 8 or 12 equal parts;
  3. locate different positions of rod QP;
  4. mark different positions of point P;
  5. join points P into a curve;
  6. use correct scale and positioning;
  7. draw neatly.

The solution is shown below: