A universal joint, also called a universal coupling or U-joint, is a joint connecting rigid shafts whose axes are inclined to each other, consisting of a pair of hinges set at 90 degrees to one another and linked by a cross shaft, used to transmit rotary motion between misaligned shafts. The English scientist Robert Hooke recorded the first known use of the term 'universal joint' in his 1676 book on helioscopes, building on a coupling design generally credited to the 16th-century Italian mathematician Gerolamo Cardano. The device remained a specialist mechanism until the American engineer Clarence Spicer and his Spicer Manufacturing Company popularized it for automotive and industrial drivetrains in the 20th century, and it is now a standard component wherever rotating power must cross an angle.
Facts
YearYear of Hooke's first recorded use of the term; the coupling design itself is credited to the earlier 16th-century work of Gerolamo Cardano per this entity's own description. SignificanceIt is commonly used in shafts that transmit rotary motion between shafts whose axes are inclined to each other. 1 FAQs
Why are universal joints often used in pairs?
A single joint gives uneven output speed; a pair set 90 degrees out of phase on an intermediate shaft evens it out.
A single universal joint does not turn its output shaft at a steady speed, even when the input shaft turns steadily. In 1683 Robert Hooke proposed a fix for this nonuniform speed: two joints placed 90 degrees out of phase at either end of an intermediate shaft. That arrangement is now known as a type of constant-velocity joint.
Connections
In Field
Source Universal Joint (Wikipedia)Wikipedia contributors
Invented By
Source Robert Hooke (Wikipedia)
Sources
1. Universal Joint (Wikipedia)
Wikipedia contributors, Wikimedia FoundationHistory section
The first recorded use of the term 'universal joint' for this device was by Hooke in 1676, in his book Helioscopes.
Lead section
It is commonly used in shafts that transmit rotary motion. It consists of a pair of hinges located close together, oriented at 90 degrees to each other, connected by a cross shaft.
In Field: Mechanical Engineering, Categories
Mechanisms (engineering)
View the Source Robert Hooke (Wikipedia)
Invented By: Robert Hooke, Article bodyQuote, Invented By: Robert Hooke, Article body
Accordingly, he invented three new mechanisms: the Hooke joint, a sophisticated universal joint that allowed his instruments to smoothly follow the apparent motion of the observed body; the first clockwork drive to automate the process; and a micrometer screw that allowed him to achieve a precision of ten seconds of arc.
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