Patent 4,067,111

Home Dedication Our Universe Buy Unique Art Donations Page NYSF Exhibit 2011 NYSF Exhibit 2010 NYSF Exhibit 2009 Westcott Art Trail Two Pendulum Harmonograph Twin Elliptic Harmonograph New Display Photos HOW TO AREA Patents Intro Patents Gallery SES STS Tile NYSF Earthquake Carbide Cannon Guest Book

Pendulum Device; T. E. Truitt, 1978

This is an over engineered version of the common sand pendulum which is widely sold in various versions and sizes as an executive’s desktop toy ingeniously called the “Pit & Pendulum” (et. al.).  These sell for around $25.00 to well over $100.00 for a fancy one.  

The pendulum configuration is a simple Blackburn’s Pendulum; which is essentially a “Y” swing; the bob rotates in infinite planes and the top of the “Y” imparts an additional back-and-forth motion to the pendulum. A Blackburn's Pendulum is also commonly found in science centers where it is sometimes presented as a sand dribbling Lissajous curve demonstration.  

This patent also mentions Cundy and Rollett's excellent book, Mathematical Models (1951) as a reference.  It’s currently out of print, but I recently heard a rumor that this timeless classic may be rereleased in a new edition.  It can still be found for sale on Amazon and eBay.

Click on an image to view full size -



Page 1 of 11

Page 2 of 11

Page 3 of 11

Page 4 of 11

Page 5 of 11

Page 6 of 11

Page 7 of 11

Page 8 of 11

Page 9 of 11

Page 10 of 11

Page 11 of 11