## Problem 2.1 Loci of Points – OBA is a simple crank chain. OB is a crank of 35 mm length. BA is connecting rod of 90 mm length. Slider A is sliding on a straight path passing through the point O. Draw the locus of the mid-point of the connecting rod AB for one complete revolution of the crank OB.

*Procedure:*

* Step-1* First draw a horizontal center line of sufficient length.

* Step-2* Draw a vertical center line and mark point O at the intersection of the two center lines.

* Step-3* Draw a circle by taking point O as center of radius equal to the length of crack OB, which is 35 mm.

* Step-4* Divide the circle into 12 or 8 equal divisions. And mark the points B

_{1}, B

_{2}, B

_{3}etc. up to B

_{12}as given into the figure. Note: Numbering should be given in the direction of rotation of crank OB. (Clockwise or Anticlockwise)

* Step-5* Draw straight lines of length equal to the length of connecting rod AB, which is 90 mm long, from the point B

_{1}, B

_{2}, B

_{3}, etc. such that these lines should connect on the horizontal center line. And give the numbers A

_{1}, A

_{2}, A

_{3}etc. in sequence as depicted into the figure.

* Step-6* Mark center points of lines A

_{1}B

_{1}, A

_{2}B

_{2}, A

_{3}B

_{3}etc. and give the numbers 1,2,3,4, etc. shown into the figure.

* Step-7* Now connects the points 1,2,3, etc. in sequence by a free hand medium dark curve.

* Step-8* Give the dimensions and name of components as shown into the figure.

* Step-9* Give the dimensions by any one method of dimensions and give the name of the components by leader lines wherever necessary.

Superb