Historic Events concerning:

  1. Tsiriggakis Gearless Differential
  2. Medicine
  3. Controllable Differential with undulated planet-gears

1. Tsiriggakis Gearless Differential

«I was observing the engineers with great admiration trying to unstuck the lorry from the mud. »

That was Mr. Tsiriggakis' first reaction when at the age of six (1953) he saw a lorry stuck in the mud outside his paternal home in a small village in Corfu. Some years later (1960), at the age of thirteen, Mr. Theodore Tsiriggakis had to leave Corfu. He came in Athens where he started to work in machine shops and studying at a nocturnal technical school called Hephaestus.

One day in 1962 on his way to school he saw a bus taking a turning, suddenly a crack was heard and the bus was immobilized. The axle shaft of a motive wheel was broken. Being a child he started to observe with great interest the chief engineer, who was trying to discover the damage. Using a jack he lifted one side of the bus, afterwards he instructed the driver to start the engine and engage the first gear. The driver for obvious reasons hesitated to follow the instructions, the chief engineer reassured him that there was no danger. As soon as the driver engaged the first gear then the chief engineer observed that both of the motive wheels were immobilized and concluded that the axle shaft of the lifted wheel was broken.

The above events triggered Mr. Tsiriggakis' curiosity and imagination in the field of transmission of motion.

In 1967 Mr. Tsiriggakis started to study the "Antikythera Mechanism", a mechanism dated back to ancient Hellas that was found in 1900 in an ancient wreckage in Antikythera island. This mechanism consists of approximately 32 gears that operate harmonically with each other in order to compute the times of the planets of our solar system and finally give our position in earth. For this reason "The Antikythera Mechansim" is worldwide known as "The Ancient Computer".

Moreover that period of time (1967) Mr. Tsiriggakis joined the Hellenic Air Force and he completed his military service as a machinist. During his military service (1968) he was assign to repair a 24-gear gearbox of a German turning lathe. But this was not an ordinary gearbox, it was a gearless one, the principle of this gearbox was based on cones and oil pressure. The damage of this gearbox was a broken cone, Mr. Tsiriggakis constructed a new cone and after the appropriate thermal processing he replaced the broken cone with the new one. After fixing the damage Mr. Tsiriggakis had a feeling of satisfaction, so he impulsively let the cone rotating around itself on the workbench. He was observing the differentiation of the rotation of the cone.

And he thought

«I will construct a Differential without Gears. »

Since the moment Mr. Tsiriggakis decided to construct a Differential without Gears he started his research in the field of transmission of motion while studying the principle of "Antikythera Mechanism".

In the beginning of the eighties (1981), after 13 years of research in the field of transmission of Motion, Mr. Theodore V. Tsiriggakis has perceived a new kinematical theory based on the principle of "Antikythera Mechanism". Based on his new kinematical theory he invented and constructed a Differential without Gears known as "Gearless Differential". "Gearless Differential" is a Differential based on a completely new concept and was patented in many countries all over the world.

From the first moment of his invention Professor Dr. Theofanopoulos supported Mr. Tsiriggakis kinematical theory.

Nowadays Mr. Tsiriggakis has invented and constructed several mechanisms based on the kinematical theory he perceived in 1981. Only some of these mechanisms are presented in our web page.

After my father has invented Gearless Differential he had the opportunity to closely cooperate with Dr. George Bournous.


In the meanwhile, apart from the field of transmission of motion, Mr. Theodore Tsiriggakis has contributed to the completion of a research program in medicine. (click here to learn more...)

3. The new Tsiriggakis Differential Mechanism (Controllable Differential with undulated planet-gears)

After the construction of Gearless Differential Mr. Theodore V. Tsiriggakis has continued his research on innovative ways of transmitting motion until nowadays. On December 1987 Mr. Theodore Tsiriggakis had already perceived a new kinematical theory.

On Friday 17th of September 2004, after 37 years (since 1967) of research and experience in the field of transmission of motion , Mr. Theodore Tsiriggakis together with his son named Vasileios T. Tsiriggakis have applied, in the Hellenic Intellectual Property Agency in Athens (Hellas), for a new patent application on the kinematical theory that he perceived in December 1987. For the needs of the patent, the inventors applied the new kinematical theory on the conventional differential. The application of this research resulted in a new critical and evolutionary Differential Mechanism called "Controllable Differentiation Differential Mechanism with Undulated planet-gears" or "Differential mechanism, of controlled Differentiation, with curved Gears" based on the hybrid kinematical theory that Mr. Theodore Tsiriggakis has presented to the NTUA in December 1987.This patent application is a result of almost two decades of research (since 1987) on innovative ways of transmitting motion that has been conducted by Mr. Theodore Tsiriggakis . The result of this research was never published until Friday 17th September 2004. The patent application number (PAN) of the new Tsiriggakis kinematical theory and its applications is 20040100369.

The title of the resulted differential mechanism that has been applied for a patent is "Controllable Differentiation Differential Mechanism, with Undulated Planet - Gears". However, for simplicity reasons we often refer to it as "The New Tsiriggakis Differential Mechanism"

Thus, the new Tsiriggakis kinematical theory and its applications (one of them being the so called "Controllable Differentiation Differential Mechanism with undulated planet-gears") were already known by the NTUA since December 1987 and they were submitted for a patent on Friday 17th September 2004.

Moreover it is very important to state that on April 2005 the first article that briefly presents the new Tsiriggakis Differential has been published.

On 13th of September 2005 the inventors: Mr. Tsiriggakis Theodoros and Mr. Tsiriggakis Vasileios have applied for an international patent (IAN: PCT/GR2005/000028) concerning the "Controllable Differentiation Differential Mechanism, with Undulated Planet - Gears".

On Tuesday, 14th February 2006 information about the new Tsiriggakis Kinematical theory and its applications were submitted to the IRC's (International Relay Centre) Database of Technology - Science and Innovation. (click here to learn more...)

On 23rd of March 2006 the international patent application was published (IPN: WO/2006/030247 A1).


Background: Tsiriggakis' Gearless Differential

Tsiriggakis.gr - Since 2003