U-ni-vers′al joint.
A device for connecting two objects, as the ends of two shafts, so as to allow them to have perfect freedom of motion in every direction within certain defined limits.
The gimbal-joint was invented by
Dr. Hooke.
In one form (
a,
Fig. 6869) it is the common mode of uniting the tumbling rods which connect the horse-power and the thrashing-machine, clover-huller, wood-saw, or other agricultural implement.
The ends of two coupling-rods are pivoted to the arms of a cross having a freedom of motion in planes at right angles to each other.
This allows flexure in any direction.
In another form (
b) the heads on the ends of the couplingrods are pivoted by pins in a ring; the pins are at right angles, and the effect the same as that just described.
c is a ball-and-socket joint in which the ball of one section is held in the socket of the other by means of an annular cap secured by its flanges to those of the socket.
A somewhat neater job (
d) may be made by making a screw cap instead of a flanged cap.
Mariners' compasses, barometers, chronometers, and some other seafaring instruments are mounted in gimbals (
e), so as to maintain an even position, horizontal or perpendicular, as the case may be, whatever may be the changes in the position of the vessel.
f is
Dr. Hooke's gimbal.
A ring is suspended by studs on diametrically opposite sides, so as to have a freedom of motion in one vertical plane, and within this ring the object itself is suspended on an axis through the diameter and at right angles to the former.
The double gimbal (
k) has been contrived for positions where a flexure of over 140° is required.
It is used to obviate the vibratory and unsteady motion incident to the action of the ordinary form of this joint.
Between the two shafts to be connected, a short intermediate shaft is introduced, making equal angles with the two principal shafts, connected with each by a Hooke joint, and having both its own forks in the same plane.
[
2683]
g is a flexible joint for water-mains.
The sphero-segmental end of one pipe passes into the enlarged end of the other, and is surrounded by an annular water-tight packing.
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Gimbals. |
h i, a flexible pipe-joint.
The flanged ends of the pipes have annular grooves to receive packing, and have freedom of motion in all directions within a twopart box, the sections of which are united by bolts.
l m n,
Keller's shaft-coupling.
A globular slotted shell enters a hemispherical shell, and is connected thereto by a pin or bolt which passes through the sides of the latter and through an axial bolt, which merely bears against the interior wall of the former, permitting the two shells to move freely about each other in all directions.
Sir Isaac Newton contrived a universal joint for the mounting of his telescope, which was made about 1675, and is now in the possession of the Royal Society, to whom it was presented by the illustrious philosopher.
See Coup-Ling; ball-and-socket joint; gimbal.
