A) Radial cam with a knife edge follower
In the radial cams, the working surface of the cam is designed such that follower moves in a plane perpendicular to the axis of the cam performing a reciprocating motion. The knife-edge followers are simple in construction. The contacting end of the follower with the cam has a sharp knife edged hence it is called so. The motion between the cam and follower is sliding. It is not used in practice because small area of contact surface results in high rate of wear at the edges due to which the transmission of motion may not be accurate as desired.
B) Cylindrical cam with roller edge follower
In this type of cam, the follower either reciprocates or oscillates in a plane parallel to the axis of the cam. In this a circumferential contour is cut in the surface of the cylinder, which rotates about its own axis. The follower rides in the groove of the cylinder surface and it reciprocates in the plane parallel to the axis of rotation. The contact end of the roller edge follower is roller and the rolling motion exists between the cam and follower. Compared to knife-edge followers, the rate of wear and tear is less due to less friction. These are used in aircraft engines and oil engines.
C) Four bar linkage system
A four bar linkage is the pre-eminent mechanism building block. Four bar linkages are common in aerospace mechanical linkages. At times, a mechanism may be a four bar linkage, but the fact that a mechanism is a four bar linkage may not be obvious.
D) Slotted link mechanism
The slotted link mechanism is a mechanism able to transform circular movement into reciprocating movement. It consists of a rotary element (graduated disk), called crank, connected to a rigid bar, called a connecting rod. When rotating the crank, the connecting rod moves back and forward. The rotation motion of a crank or crankshaft causes a rectilinear reciprocating motion of a piston or plunger.
Question 2
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