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Eccentric Cam

From DT Online

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Drescription

Cams with complex profiles can be complicated to manufacture, particularly with the type of equipment available in the school workshop. However, if all that is required is to produce a single up and down motion for every revolution on the cam, a circular cam rotating about a point offset from its centre (i.e. eccentric), will often suffice.


Features and Applications

An Eccentric Cam would normally provide the follower with Simple Harmonic Motion - (this can be defined as the projection of a point on the diameter of a circle as it precesses around it with constant angular velocity).


Note: They can be modelled, in wooden mechanical toys for example, by drilling a Ply or MDF disc off-centre and gluing it on to a rotating Dowel.


Note that the cam follower need not just move up and down in a reciprocating motion, but it can be a lever as shown, which will produce oscillating motion.


Animations
Eccentric Driven Pump - the red arrows indicate the rotation direction of the eccentric shaft and the

fluid moving direction. The front half of the case is removed.

DT Online Buyers' Guide
  • The use of Cams can most easily be explored using Contruction Kits such as those listed below.

Click top left to enlarge

Engino Engino ENG-M06 Cams and Cranks Engino Fischertechnik 536622 - Mechanic & Static 2 Simple And Motorized Mechanisms Base Set Engino Education Design And Technology Master Construction Set, Covering Simple Machines, Structures, Bridges, Rewable Energy, Forces And Energy Motion
Engino "STEM Mechanics" Cams and Cranks Set Engino ENG-M06 Cams and Cranks Engino "STEM Mechanics" Levers and Linkages Set Fischertechnik 536622 - Mechanic & Static 2 Simple And Motorized Mechanisms Base Set Engino Education Design and Technology Master Construction Set