Spi′ral spring.
A coil whose rounds have the same diameter, and which is generally utilized by compression or extension in the line of its axis.
The balance-spring of a chronometer hence is spiral, and is utilized by an expanding and contracting action in a plane at right angles to the axis.
See
Fig. 532.
A helical spring has coils of decreasing diameter as they approach the center, like the mainspring of a watch.
(See movement,
Fig. 3246.) The spiral spring is used in
Salter's balance and in
dynamometers; also in bedstead-springs, as in
Fig. 623, page 261.
Fig. 5418 shows a double helical bedstead-spring, the coils increasing upward and downward from the point of smallest diameter at the mid-hight.
Fig. 5419 shows some applications of the spiral form to car-springs.
A number more are shown at
Fig. 1143, page 483.
a b are respectively a vertical section and a horizontal section of
Godley's car-spring.
The case is open at top and bottom, and has a central fixed diaphragm, against which the concentric spirals abut.
c is
Godley's spring, with an open end and a sliding partition.
[
2276]
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Spiral car-springs. |
d is another of
Godley's springs, having flat surfaces at the portions liable to come together, and webs of lesser thickness beyond the contacting surfaces.
e is
Allen's conical spring with spiral coils of upwardly decreasing diameter.
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Car-springs. |
f, a spring having an inner edge of greater vertical thickness.
g, a spring made of metallic strands or strips, twisted or braided and then coiled.
In
Fig. 5420,
a b c d e f are springs of the
Culmer Spring Company.
g h,
Nichols,
Pickering, & Co., spiral spring.
i, the
Vose spring.
