The double straight spring is used in omnibuses, carts, &c., where it is fixed across the angle at right angles. It is called a “double-elbow spring.”
The regular curved spring is in form generally two-thirds of a circle, one end of which is lengthened out into a tangent, which serves as a base to fix it by in an upright position; the body is suspended from the other extremity by means of leathern braces. Its general figure has caused it to acquire the technical name of C spring. (See [Fig. 25].)
The combination known as “telegraph spring” consists of eight straight springs, when used for a four-wheeled carriage, and four springs for a two-wheeled carriage. The Stanhope is suspended on four of these springs. Two springs are fixed longitudinally on the framework, and two transverse ones are suspended from these by shackles, and on these latter the weight rests. They will bear a great weight, and the body has the advantage of being placed two removes from the concussion.
Fig. 27.
[Fig. 27] shows some varieties of springs.
a Has semi-elliptical springs, hung upon the ends of C springs attached to the axles.
b Has the usual elliptical springs between the bolster and axle.
c Has elastic wooden springs, which connect the axles and support the beds.
d Has some elliptical springs, which also couple the axles A and B.