﻿ Straight-Line Mechansims

# Straight-Line Mechanisms

## Straight Line Mechanisms

This topic is simply a list of some of the important Straight-Line Mechanisms. Not Mechanism Synthesis.

They are included for reference.

 A. Straight-Line Mechanisms with Pin-Joints only

In each image, the Pin-Joints are given a letter. The input joint is at A. You can scale each mechanism from the relative lengths of each Part. The Point at letter 'K' is the coupler point and it moves in a straight-line.

 B. Straight-Line Mechanisms with Pin and Slide-Joints

There are also straight-line mechanisms that have a Slide-Joint! This might seem ridiculous as why produce a straight-line with a mechanism when it should be easy to use the linear slider directly!

However, when the slide-joint moves only a short distance as compared to the distance the coupler point moves, then they are useful.

Also, they are sometimes useful to change the straight-line motion to a different direction.

#### Straight-Line Mechanism with Pin-Joints Only

 See YouTube video http://youtu.be/JlGKZCus6iw Watt Straight-Line Watt - Pop-up AB=-BC=CD=L AD(δx) = 2L AD(δy)=L BK=CK=0.5L Roberts Strain-Line Roberts Pop-up AB=CD=AD=BK=CK=2L BC=L Tchebycheff & Translating AB=CD=2.5L AD=2L BC=L BK=0.5L FK is the Translating Part. CE=EF=1.25L ; FK=L Modified Scott Russell AB*BC=BK2 CD= longer the better Hoeken AC=L AB=2L BD=CD=2.5L D.K=2.5L Peaucellier 1 - EXACT STRAIGHT LINE AD=DC=1L AB=AE=2.5L BC=BK=CE=EK=1.2L Peaucellier 2 - Inverse - EXACT STRAIGHT LINE AD=AB=1L DC=DE=1.25L BC=CK=BE=EK=1.5L Kempe 1 AB=BC=DC=AD=2L AE=EC=EK=1L CF=FK=0.5L Kempe 2 AB=DC=BE=CF=CK=1L AD=BC=EF=AK=2L GK=FG=0.5L Notice that four Parts are Blue - this means that MechDesigner solves their postilions, but not with closed loop equations. Hart AB=AD=3L BC=DC=6L AE=L EG=4L DF=GF=FK=2L Hart - EXACT STRAIGHT LINE AB=AD=1L DC=DE=1.4L BC=BF=EK=3L EG=6L FG=2.8 Translating Table - or Engineers Table

#### Straight Line Mechanisms with Pin-Joints and Slide-Joints ### Scott Russell

AB=BC=BK

CD= ∞ (D @ infinity -Y)

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