Steam Engine Valve Mechanisms

D'-slide valve

Meyer's Expansion Gear

Corliss Valve
http://oldenginehouse.users.btopenworld.com/corliss.htm

The Walschaert Valve Gear

Mechanisms with Lower Pairs - Theory of Machines - Chapter Contents

What is a lower pair?
If a pair has a surface contact between the two elements while in motion, it a called lower pair. sliding and turning pairs are lower pairs.

Pantograph

It is mechanism used to create straight line motion that is used to enlarge or reduce movements given at the input side.

Peaucellier's Mechanism

http://me.lsu.edu/~ram/TEACHING/kinematics/Peaucellier.pdf

Hart Straight Line Mechanism


Kempe's Mechansim

Scott Russel Mechanism

Watt Straight Line Mechanism

Modified Scott Russel Mechanism

Grass Hopper Mechansim

Tchebicheff Straight line mechanism

Robert's straight line mechanism

Straight Line Mechanisms used in Engine Indicators

Simplex indicator

Crosby indicator mechanism

Thomson indicator mechanism

Dobbie McInnes indicator mechanism

Acceleration Analysis in Mechanisms

Finding the acceleration of various links is important to know the forces that the link has to withstand. The normal acceleration is proportional to the square of the speed. Doubling the speed of any link will mean increasing the centrifugal forces four times.


Acceleration Analysis
http://facultad.bayamon.inter.edu/elay/mecn4110/Acceleration%20Analysis.pdf

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Velocities in Mechanisms: Velocity Polygons

Velocities and Accelerations - Included instantaneous centers, velocity polygons and acceleration

http://www.pua.edu.eg/PUASite/uploads/file/Engineering/spring2011/ME212/Chapter%20II.pdf

Relative Velocity Method - Dr. David Herrin
http://www.engr.uky.edu/psl/ME380/pdf%20files/kin4.pdf

Velocities in Mechanism: Instantaneous Center Method

Instant Center of Velocities
http://www.u.arizona.edu/~pen/ame352/Notes%20PDF/6-IC%20general.pdf

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Motion of Particles of Links of Mechanisms

A mechanism is a kinematic chain with one of the links in a fixed position. In a mechanism (which is a kinematic chain) every particle of every link must move along a definite constrained (pre-estimated or pre-specified) path which may be a straight path or curvilinear path. Generally the curvilinear path may be an arc with a fixed radius or an arc with a different radius from instant to instant.

Associated with motion are concepts of velocity, acceleration, angular displacement, angular acceleration and harmonic motion.

Motion occurs due to force. Momentum is defined as mass multiplied by velocity, and forced is defined as change in momentum and it is thus equal to mass and acceleration.

Automatic Machines and CNC Machines

Authors

• Narayana Rao

Published

All Rights Reserved

Version 7

Last edited: 10 Oct 2011

Exported: 26 Nov 2011

Original URL: http://knol.google.com/k/-/-/2utb2lsm2k7a/3367

 

 

Knol search link for articles on CNC 

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• CNC Coordinate Rotation (G68)
  A very useful function to ease in the programming and set-up of machined castings.

Comments

Short urls

http://knol.google.com/k/-/-/2utb2lsm2k7a/3367

Narayana Rao - 11 Feb 2011