Some days, a little creativity is needed to make a driving and driven shaft come together. Somehow, someone got the shaft size a little bit wrong and you’ve got three hours to bring it all together.
Make the rabbit that you pull out of your hat one of our standard Curtis u-joints that can be machined on the spot to slide onto the mismatching shafts. Take our stock joint with the capacity to match the application requirements, take ten minutes to bore it to the shaft specifications, and you are in business.
If you are expecting the unexpected in an application, maybe it’s best if you take along a u-joint that is capable of it’s own trickery. A Curtis u-joint that incorporates a sliding spline can accommodate shaft displacement as well as misalignment. Add a second joint to the end of it and you can almost make the torque turn a corner. So, where an application has a chance to toss you a curve ball, think B/P joints first.
The concept of the universal joint came, historically, from the same source of genius that brought us spaghetti, paper, gun powder, and a long wall — we call it the “Great Wall” — that is the only man-madeobject that is visible from outer space.
You guessed it. U-joints were first conceived in China, about the time the West began to keep track of days on the Julian calendar. The Chinese invented the gimbal which they used to keep candles upright under changeable conditions. Not sure why they needed to do that, but gimbals found a use on ships to keep compasses level and in aircraft to suspend gyroscopes.
The Chinese may have had the original idea, but it took an Italian named Cardano (no doubt grateful for the spaghetti) to visualize the gimbal as a universal joint. Later, an Englishman named Hooke perfected it and applied it to optical instruments.
Two things were necessary to make the universal joint… well,universal. The first was Clarence Spicer who received a patent for it in 1903 while he was still a student at Cornell University. Spicer was one of those rare creative people who come along just when they are needed. At that time, other people in Detroit, Cleveland, Indianapolis, and other places (Plattsburg, NY?) were busy trying to adapt engines to carriages. Instead of belts, chains, and cumbersome gears, u-joints provided the means of smoothly getting torque around a corner.
Curtis got into the act in 1936, in the niche for block-and-pin joints for a myriad of industrial and commercial applications. We like to feel that we moved the technology forward with our trademarked TakeApart™ design that enables users to replace worn parts almost instantly. Today, you will find Curtis u-joints in everything from submarines to farm equipment to commercial washing machines.
All because someone in China wanted to keep their candles upright.
A B/P u-joint is not a flexible shaft, but sometimes it can act like one. A single B/P joint can handle up to 35 degrees of misalignment between two shafts. Two joints linked together in series can accommodate 70 degrees of misalignment. The typical cross-type joint can only manage about 20 degrees of misalignment.
So, when the misalignment is deep into double digits, think B/P joints first.