A cam is mechanical member used to import desire motion to a follower by direct contact. The cam may be rotating or reciprocating whereas follower may be rotating, reciprocating or oscillating.
It is used in automatic machine, IC engine , mechanical tool, printing control mechanisms.
Element of Cam :-
A driver member known as the Cam
A driven member known as the follower
A frame which support the cam and guides the follower.
Point of remember :-
A cam and follower combination belongs to the category of higher pair.
Type of cam :-
1. according to the shape -
* wedge and flat cam :-
a wedge cam has a transitional motion, the follower can either translate or oscillate.
* Radial and disc cam
The cam in which the follower moves radially from the center or rotation of the cam is knows as the a radial or disc cam.
* Spiral cam
A spiral cam is a face cam in which a groove is cut in the form of spiral. it is used in computer.
* Cylindrical cam
In a cylindrical cam, a cylinder which has a circumferential contour cut in surface, rotate about its axis. it also known as barrel and drum cams.
* Conjugate cams
it is a double disc cam and preferred when the requirements are low wear, low noise , better control of the follower, high speed, high dynamic load etc.
* Globoidal cams
it has two type of surface i.e convex or concave. it is used when moderate speed and the angle of oscillation of follower is large.
2. According to the follower movement :-
* Rise-Return-Rise (RRR)
In this there is alternate return and rise of the follower with no period of dwells. The follower has a linear or a angular displacement.
* Dwell-Rise-Return-Dwell (DRRDS)
In this cam, there is rise and return of the follower after the dwell.
* Dwell-Rise-Dwell-Return-Dwell (DRDRD)
The dwelling of the cam is followed by rise and dwell and subsequently by return and dwell. In case the return of the follower is by a fall, The motion may be known as Dwell-Rise-Dwell (DRD).
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