Question 2
Fig. 1 shows a crank mechanism having F as centre. The rod PY slides through pivot E and is connected to the crank. Plot the locus of a point P when the crank makes one revolution.
Observation
This is a question on constructing the locus of a point in a crank mechanism.
The solution to this question lies in making the rod PY slide through the pivot E.
The question was well attempted and good result was recorded.
Strength:
Most candidates were able to:
- copy the given mechanism;
- draw circle R40 and divide into 8/12 equal parts;
- locate corresponding different positions at rod PY on crank FY;
- join points P into a smooth curve.
Candidates were expected to:
LINK MECHANISM
i. copy the given mechanism (crank FY, rod PY, slot E, centre lines);
ii.draw circle R40 and divide into 8/12 equal parts;
iii.locate corresponding different positions of rod PY on crank FY;
iv.mark different positions of point P on rod PY;
v.join points P into a smooth curve;
vi.correct positioning of parts of link mechanism;
vii.neatness and quality of linework.
The solution is shown below:
