The transformation of one of the easy motions, such as rotation, into any other motions is often favorably closed by means of a cam mechanism. A cam mechanism regularly consists of two spellbinding elements, the cam and the follower, mounted on a fixed frame. Cam devices are versatile, and practically any arbitrarily-specified motion can be obtained. In some instances, they offer the simplest and most covenant way to transform motions.
A cam may be defined as a motor element having a curved figure or a curved groove, which, by its oscillation or rotation motion, gives a predetermined specified motion to an additional one element called the follower. The cam has a very foremost function in the carrying out of many classes of machines, especially those of the self-acting type, such as printing presses, shoe machinery, textile machinery, gear-cutting machines, and screw machines. In any class of machinery in which self-acting operate and literal, timing are paramount, the cam is an valuable part of mechanism.
Rotary Motion
A cam is a specially shaped component that serves to guide the motion of a component called a follower. The cam has a rotary or linear motion. The most foremost benefit of cam principle is that it is quite favorably possible to introduce pauses of any desired length into the motion. This benefit is widely used in machinery of all kinds, such as packaging machines and many others. Using cams it is possible to accomplish easy sliding movements or oscillatory. It can also for real controlled movements of account for shape.
For e.g, Guiding a milling cutter along a curved figure of any desired shape. A cam mechanism basically consist three parts: the frame or base (a), on which the cam (b) is mounted, and the follower (c) whose motion is controlled by the cam, which is given a linear or a rotary ( motion. A follower is a component which is specially shaped component of cam used to guide its motion.
A suitable example of a cam mechanism is the valve gear of an internal-combustion engine. The rotating cam has an practically pear-shaped profile comprising two circular curves joined by two right lines which are tangential to those curves. The follower consists of a roller tappet which is moved up and down by the cam and imparts this motion to the rod that controls the opening and windup of the valve. The center of the roller traces a curve of similar shape to the cam profile.
The stroke, the speed and the acceleration of the roller tappet have been plotted against the angle of rotation the acceleration undergoes a sudden convert in value, which imparts a jerk to the tappet. This occurs every time the radius of curvature of the cam profile changes abruptly e.g., transition from circular curve to tangent and vice versa. Conversely, it is possible to start from a determined acceleration curve that comprises no abrupt changes and create a cam so shaped as to polite acceleration, free of jerks.
Cam Mechanism