Linear Cam

Description

Linear cams move backwards and forwards in a reciprocating motion and the shape of the surface of the cam determines how far, and in what manner, the ‘follower’ moves in response.

Features and Applications

Most cams are design using a Displacement Diagram - essentially a graph which plots the cam movement against the follower movement. A linear cam can be imagined to be the shape of the graph cut from solid plate and then passed backwards and forwards beneath the follower.

Note: A simple wedge can be regarded as a basic form of linear cam - when driven into the end of a timber log, or used as an axe, the wedge transfers the vertical linear motion of the hammer into a horizontal force which spilts the wood.

Animation

Examples from Nguyen Duc Thang's YouTube Channel 2100 Animated Mechanical Mechanisms

Linear Cam - as the Cam Plate Reciprocates, the Follower Rises at one end of the stroke and Falls at the other with periods of Rest in between

DT Online Buyers' Guide

Cam profiles (i.e. the shape of the outer edge of the cam against which the Follower engages) can be drawn as a Displacement Diagram using Drawing Instruments or CAD software.

Cams for models can be made simply by drilling an MDF or Ply Disc off-centre to make an Eccentric Cam or by mounting a disc at an angle to a dowel axle to make a Swashplate.

The use of Cams can most easily be explored using Contruction Kits such as those listed below.

Click top left to enlarge


Engino "STEM Mechanics" Cams and Cranks Set	Engino "STEM Mechanics" Levers and Linkages Set	Fischertechnik 536622 - Mechanic & Static 2	Engino Mechanisms Set	Engino Gears Set