A giubo, also known as a flex disc,http://www.pelicanparts.com/bmw/techarticles/E36-Guibo/E36-Guibo.htm and sometimes misspelled as guibo, is a flexible coupling

Coupling

A coupling is a device used to connect two shafts together at their ends for the purpose of transmitting power. Couplings do not normally allow disconnection of shafts during operation, however there are torque limiting couplings which can slip or disconnect when some torque limit is exceeded.The...

 used to transmit rotational torque between the drive shaft and the companion flange

Flange

A flange is an external or internal ridge, or rim , for strength, as the flange of an iron beam such as an I-beam or a T-beam; or for attachment to another object, as the flange on the end of a pipe, steam cylinder, etc., or on the lens mount of a camera; or for a flange of a rail car or tram wheel...

 on mechanical devices, such as an automobile engine. The giubo is made from flexible rubber and is designed to allow some angular misalignment while reducing driveline vibration in mechanical power transmission applications.

How it works

Input and output shaft flanges are bolted to the giubo on either side using alternating hole positions, so that the flanges are not connected directly to one another but instead only through the rubber material of the coupling. The elasticity of the rubber absorbs vibration and flexes for alignment. It follows that the rubber must withstand the application's full transmitted torque, for which reason the rubber is often reinforced internally using moulded-in fibre material.

Name

Giubo is a contraction of the Italian

Italian language

Italian is a Romance language spoken mainly in Europe: Italy, Switzerland, San Marino, Vatican City, by minorities in Malta, Monaco, Croatia, Slovenia, France, Libya, Eritrea, and Somalia, and by immigrant communities in the Americas and Australia...

 word giunto ('joint' or 'coupling') and the surname of the Italian engineer who designed and patented the first flex disc, Antonio Boschi (b1896-d1988)http://www.fondazioneboschidistefano.it/ws/. He later founded GIUBO SpA, a company solely dedicated to manufacturing flex discs.. The giubo, today well known in automotive use, is believed first to have been used for this purpose on the Alfa Romeo model 1900, produced between 1950 and 1959.