Mechanical Design

Mechanical Design 101

Mechanical Design Educational Resource

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Month: April, 2009

Timing belt theory

29 April, 2009 (15:43) | Engineering Data | By: jmmccart

ThomasNet provides a link to a useful white paper on Timing Belt Theory by Gates-Mectrol:

http://www.thomasnet.com/white-papers/abstract/101106/timing-belt-theory.html

Geometric data on timing belt drives can found in the catalog linked to Gates-Mectrol home page:

http://www.gatesmectrol.com/

gates-mectrol-logo1

Gear geometry

29 April, 2009 (05:12) | Engineering Data | By: jmmccart

Gear geometry data is available from PIC Design Inc. which is now part of RBC Bearings at the link:

http://www.pic-design.com/static/PDF/Catalog%2045.0.pdf

RBC Bearings Logo

RBC Bearings Logo

Stock Drive Products provides an on-line Handbook of Gears at the website:

http://www.sdp-si.com/D190/D190cat.htm

Stock Drive Products Logo

Stock Drive Products Logo

The Gleason Gear Encyclopedia is available for sale at the site:

http://www.quikey-c.com/gleason/SKUDetailsGLEAFGL6000.Asp

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The American Gear Manufacturers Association provides standards for sale on-line at the site:

http://www.agma.org/Content/NavigationMenu/Publications/TechnicalPublicationsStandards/AGMAStandardsInformationSheets/default.

AGMA Logo

AGMA Logo

Mechanisms videos at Colorado State

28 April, 2009 (15:20) | Linkage Animations | By: jmmccart

Prof. David Alciatore has a large number of videos illustrating machines, physics principles and billiards, including high speed videos.  Video demonstrations of mechanisms can be found at the following site as well as links to much more:

http://video_demos.colostate.edu/mechanisms/index.html

Spherical deployable linkage assembly

27 April, 2009 (22:00) | Linkage Animations | By: jmmccart

This assembly of spherical rhombus linkages expands to enclose a volume.  It was designed by Jerome Choe to explore the construction of complex articulated systems. (UCI Robotics and Automation Lab)

YouTube Preview Image

C. J. Sangwin’s linkage movies

27 April, 2009 (04:21) | Linkage Animations | By: jmmccart

Chris Sangwin has a nice collection of linkage movies on his web-site http://www.howround.com.  Particularly nice are the straight line mechanisms found at the link:

http://web.mat.bham.ac.uk/C.J.Sangwin/howroundcom/straightline/exact.html

His example of the Sarrus linkage is also found on YouTube:

YouTube Preview Image

Brock Engineering’s mechanism home page

27 April, 2009 (03:17) | Linkage Animations | By: jmmccart

Fred Klingener has generated a number of interesting mechanism animations.  My favorite is the Peaucellier straight line mechanism.  You will find a table of 16 or so animations at his site:

http://www.brockeng.com/mechanism/index.htm

Brock Institute Logo

Brock Institute Logo

Linkage animations on synthetica

27 April, 2009 (00:12) | Linkage Animations | By: jmmccart

This link connects to a web-page with a number of linkage animations. There are several planar four-bar linkages, several spherical four-bar linkages, and an example of a spatial four-bar linkage called a Bennett linkage that is shown below. This page also includes a number of spherical linkage animations generated by students some years ago. (UCI Robotics and Automation Lab)

http://synthetica.eng.uci.edu/~mccarthy/Linkages.html

This animation was generated by HaiJun Su using POV-Ray. It is a Bennett linkage designed to guide the coupler linkage through three specified task positions:
YouTube Preview Image

Kinematic models for design

26 April, 2009 (23:51) | Linkage Animations | By: jmmccart

The KMODDL team at Cornell University maintains an excellent digital library of kinematic models with animations.  Access their site at the link:

http://kmoddl.library.cornell.edu/

KMODDL Logo

KMODDL Logo

Machine screw dimensions

26 April, 2009 (06:34) | Engineering Data | By: Prof. McCarthy

According to Shigley and Mischke’s Mechanical Engineering Design (McGraw-Hill 1989) experiments show that the tensile stress supported by a threaded rod equals that of a rod with diameter that is the mean of pitch and minor diameters of the threads.  Thus, the tensile stress area of a threaded fastener is computed from the average of its pitch and minor diameters.

  • Here is a link to Instock Fasteners which provides ANSI/ASME screw thread sizes:

http://www.instockfasteners.com/Tools/ScrewThreadTables.ASP

  • Marine Fasteners lists the thread sizes and provides sizes for tap and clearance holes:

http://www.marfas.com/machinescrewtapping.shtml

This site also shows the various types of machine screw heads.

  • Engineers Edge provides a table of thread sizes at:

http://www.engineersedge.com/screw_threads_chart.htm

  • And head dimensions can be found at SmithFast:

http://www.smithfast.com/msflathead.html

Spherical eight-bar linkage for a car door

26 April, 2009 (00:05) | Linkage Animations | By: jmmccart

This spherical eight-bar linkage was designed by GimSong Soh to guide a car door from the side to the top of the vehicle. This animation shows the versatility of movement provided by these linkages. (UCI Robotics and Automation Lab)