coincident points

COINCIDENT POINTS

• When a point on one link is sliding along another rotating link, then the point is known as coincident point.

•  In other words, coincident point is the point on the slider such that the slider slides along the another rotating link.

• The position of coincident point varies as the slider moves in between its extreme positions.

• Illustration: We can have coincident points only when a point on a link rotates as well as slides as in the case of crank and slotter lever mechanism, Whitworth quick return mechanism, and swivelling joint mechanism.

• Fig.2.22 illustrates the location of the coincident point in a crank and slotted lever quick return mechanism in a shaper machine.

1. Significance of Coincident Point

•  Whenever a coincident point exists in a mechanism, to find the total acceleration at that point we have to calculate one more acceleration component which is known as Coriolis component.

• Therefore, total acceleration at a coincident point about another point in a link is the vector sum of their radial acceleration, tangential acceleration and the Coriolis acceleration.

We shall discuss the Coriolis component of acceleration of various mechanisms in the following article.