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Computer assisted design of planar workholders

There are many situations in which contact between two
bodies is at a single point so there can be no tensile
(force). This form of contact only provides a single degree
of restraint, and is defined as a unidirectional point
contact. The analysis of Reuleaux shows that four suitably
placed frictionless point contacts are required to
completely restrain an object in a plane.
The objective of the thesis is to allow user-placement
of three contacts and to find acceptable range for placement
of the fourth. If the fourth contact is anywhere in the
range, the four forces fulfill the requirement for total
planar restraint, i.e. all translations and rotations in a
plane are prevented. This project considers the directions
and placement allowed for the fourth force but does not take
into consideration the magnitudes or friction coefficients
of any of the four forces.
In this research a program named Planar Restraint
Design Assistant (PRDA) was developed to analyze positions
of the four restraint forces. A planar object is first
specified by the user; the program accepts AutoCAD images
for more complex objects. For three given restraint forces
PRDA determines a range of the fourth force such that total
restraint is achieved. In addition, PRDA allows the user to
arrange three restraint forces until a desired range of the
fourth restraint force is obtained. Results are shown in
visual form with accompanying graphs for numerical
interpretation. A program user's guide and a program
learning guide are provided as shown in the report with
illustrative examples. Program source code in QuickBASIC is
included in the report. / Graduation date: 1995

Identiferoai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/35128
Date30 June 1994
CreatorsChancharoen, Ratchatin
ContributorsFichter, Eugene F.
Source SetsOregon State University
Languageen_US
Detected LanguageEnglish
TypeThesis/Dissertation

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