22-08-2013, 12:56 PM
Computer-Aided Design and Analysis of the Whitworth Quick Return Mechanism
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Abstract
This report discusses the design and implementation of a software package for the computer-aided design
and analysis of the Whitworth Quick Return Mechanism. The kinematic analysis of the Whitworth Quick
Return Mechanism is discussed with details on how the position, velocity, and accerleration were calculated.
The dynamic anaylsis of the Whitworth Quick Return Mechanism follows. A description of the software
package is given as well as the package API. A Whitworth Quick Return Mechanism class was created that
allows users to easily calculate the position, velocity, acceleration, and forces at each linkage point given an
input torque. The class also allows users to find the required input torque given an input force. The class
utilizes the available xlinkage software to display an animation of the Whitworth Quick Return Mechanism.
Introduction
The implementation of a Whitworth Quick Return Mechanism can be useful for applications requiring slow
initial force and a quick reset operation. The design of such a Whitworth Quick Return Mechanism can be
tedious to do by hand. High-end commercial computer applications are available that can help in designing
a Whitworth Quick Return Mechanism but these applications are usually large and come with other pack-
ages that are not essential to the specified task. These commercial applications are also expensive for the
general user. For students earning a degree in mechanical engineering, these black-box commercial software
packages are suitable for explaining some basic principals and concepts with traditional graphic methods.
In order to fully comprehend the subject matter, students must utilize numerical and analytical methods to
solve complicated engineering problems. A general purpose Whitworth Quick Return Mechanism software
package is required that allows the general public to be able to quickly design and implement a Whitworth
Quick Return Mechanism. Such a package would require a simple user front end and easy to understand
API. Users should be allowed to fully integrate the software package into their own code with the ability to
either choose to specify an input torque or required output force. Students most benefit from an open soft-
ware package as compared to a black-box software package. Students are able to go through and examine
the available source code and modify it to solve similar problems. By learning from examples, students will
better understand the principles and numerical aspects of the subject matter.
Dynamic Analysis of the Whitworth Quick Return Mechanism
Utilizing the previous analysis of position, velocity, and acceleration along with the inertia properties, such
as mass and mass moment of inertia of each moving body, we are now able to perform force analysis on the
Whitworth Quick Return Mechanism. This is done by pulling apart the Whitworth Quick Return Mechanism
and determining the static force equations of each member. This model will neglect friction forces. When
the force equations for all members have been found, a matrix equation can be formulated and the required
torque input for a wanted force output of the output slider, link 6, can be found.
Conclusion
This report presented a software package for the analysis and design of a Whitworth Quick Return Mecha-
nism. The CQuickReturn class can be used to calculate or plot the position, velocity, and acceleration of the
mechanism. The CQuickReturn class also provides a function to create an Xlinkage animation file display
the changes in configuration of the mechanism overtime. This package is well suitable for rapid prototyping,
distance learning, and as a teaching aid.