US30577A - Truss-bridge - Google Patents

Description

"UNITED STATES PATENT OFFICE.

JONATHAN L. JONESVOF ST. LOUIS, MISSOURI.

TRUSS-BRIDGE.

Specication of Lettersatent No. 30,577, datedNovembei 6, 1860.

ing had to the accompanying drawings,

forming a part of this specification, in which- Figure l, represents a longitudinal vertical section; Fig. 2, a horizontal cross section,and Fig. 3, a vertical cross section of my improved metallic truss bridge; Fig. 4:, a detached view; Figs. 5 and 6 are sectional views of a diagonal brace. Fig. 7, is a perspective View of a portion of the lower chord &c.

Similar characters of reference in each of the several figures indicate corresponding parts.

The trusses of this bridge consist of a system of chords and stringere, braces and screw "rods, all arranged in such manner that the component parts of each truss can accommodate them-selves to such variations in the camber or vertical curvature of the bridge as may be produced by changes of temperature, heavy weights, and similar causes.

The nature of my invention consists, tlrst, `in the iiexible scarfed splice in the lower chord, when said splice is formed of broad flat plates with lateral curved offsets or lugs formed on their ends, said oisets pulling against one another and allowing a `free in` dependent movement of each plate in the path of a vertical circle, as hereinafter described.

It consists, second, in combining the convex j surface of the blocks above and hereinafter described with corresponding concave flan ges at the ends of the tubular braces for the purpose of insuring a perfect bearing of these parts during any change in the camber or vertical curvature of the bridge that may be produced in adjusting the same, or by `the expansion or contraction of the chords,

`portion of the convex block-but does not prevent the free motion of the joints.

It consists, fourth, in combining thebottom stringers of the bridge with grooved shoes for the three fold purpose of sustainingthe iioor beams, preventing any possibility of the collapsing or `buckling of `the `wroughtiron chords or plates and to assist in forining the lateral fastenings between two trusses at the bottom.

It consists, iifth, in constructingthe diagonal tubular brace with a septum or "longitu- `dinal partition and transverse tubes asfhereinafter described.

It consists, siXth,in the peculiarconstruction ot' the "metallic abutment shoe upon which the truss rests at its extremities.

To enable others skilled in the `art `to make and use my invention, I will proceed to describe its construction and operation. The system of bottom chords consists of independent sections `or plates of `wrought iron o, a, a, `7), 5,2), c, c, o, Fig. 2, `whichare provided with a shoulder forming a joint at each end. The inner edge ofthe shoulder of one plate is intended to bear against the inner edge of the shoulder of the neXt plate as shown in Fig. 2 when for instance `the shoulders 29 P of the plates b o are represented as locked into and resting against the shoulders 0 0 of the plates c o. The edges y, e, of the shoulders in contact with each other are rounded as seen in Fig. .41, so that a perfect bearing will be insured although t-he angle which the two 4'lQlates form with each other may change. The shoulder ends of the plates `thus hooked or locked into each other are sunk into corresponding recesses in the tops and bottoms e of the blocks, thereby clamping `and `preventing the splicer or joints frombecoming unjointed by lateral or other motion, and at the same time retaining the entire strength of the iron chords by avoiding the use of bolts or rivets passing through the chords. These recesses in the blocks are madeilaring from the center of the blocks toward the outside as shown at zu so that the plates can change the angle they form with each other and thus accommodate themselves to the varying camber of the bridge without being strained in the blocks d e. The stringers a at each end of the bridge pass through Slots in a shoe and are provided with shoulders a" at their outer endsresting against the outer face j of the shoe. The shoe has an extension j j in the rear as seen in Figs. 1 and 2.

The wrought iron tension plates or top stringers g, It, 7l are locked into each other by means of the same splice or joint employed to connect the chords below, as before described and are designed to prevent any derangement of the plates in adjusting the truss when raising the bridge.

In addition to the top stringers above described, cast iron tubular braces e are placed longitudinally between each two of the blocks CZ, e', to the convex surface of which they are fitted by the corresponding concave surfaces of the ends of the above described tubular braces z. These braces are designed to act as plates and to resist the compressive action of the upper portion of the bridge while sustaining its own weight or a heavy load previous to which in raising the bridge they are held to their places by the action of the screws of the top stringers and the diagonal screw bolts at the end of the bridge.

TheY blocks (0l e) clamping the bottom .i stringers and the blocks (cl e) clamping the center tension plates of the top, are fastened ,together by vertical screw rods (f). The

top blocks (d e) of the Vupper stringers at each end of the bridge are held to the shoe (j) or lower end block by similar screw rods (f). These upper blocks at the intersecting point of each section of the truss answer a three-fold purpose-first, that of a bearing for the diagonal braces; second, as a clamp for the splicer of the tension plates of the upper stringers and, third, to assist in forming a part of the cylindrical knuckle joints of the upper plates or tubes as before mentioned.

To make the truss a self sustaining structure of the necessary rigidity a series of diagonal braces (o) are arranged in the usual manner, as fol ows: A tubular counter brace extends from the first block Z e of the top stringers to the second block of the chords; another brace parallel to the iirst extends from the second block of the top Stringer to the third block of the bottom chord, a similar counter brace being inserted into each section successively.

At the extreme end of the truss a pair of main braces (o, 0,) extend from the convex (8,) at the outer end of the shoe (j) to the first block on the extreme end of the top stringers or tubularplates. Then a pair of main braces diagonally crossing outside of the before described counter braces is extended from the interior convex end of the shoe (j) to the second block of the tubular plates or stringers. A parallel pair of braces also extends from the second block of the chord to the third block of the top and so on successively.

The surfaces of the shoe as seen at (la) and of the blocks against which the ends of the braces (0) bear are convex and the ends of the braces are provided with concave i'ianges (t) of a corresponding curve. Thus it is seen a perfect bearing of these parts will be insured during such slight changes in the relative portions of the component parts of the bridge as will occasionally occur for reasons before named. The lower ends of Vthe braces (o) are also provided with similar concave flanges (t) resting against the convex portions of the shoe. The two end braces (0) are connected by atransverse tube (p) and bolt (1*) passing through the braces and transverse tube. rThe braces (o) are at the point of intersection constructed with transverse tubes (p) the ends of which may be enlarged and extended from the outer circumference of the brace so as to rest against each other, or they may terminate at the outer circumference of the brace as shown in Figs. 5 and 6. Bolts (1) pass through these transverse tubes and hold the braces together in a transverse direction, at the same time allowing them to play around the bolts as Ytheir center. In order that the braces may have suflicient strength at these points of intersection and still be light, they are made hollow and strengthened by a septum or longitudinal partition (Fig. 2) which comes within the bore of the brace and ties the upper and under portions of its inner circumference together in the manner represented in Figs. 5 and-6 of the drawing. By this mode of construction it is obvious that great strength is imparted to the braces and they are thereby enabled to resist the cross sectional strain which is produced to a considerableV extent byl the longitudinal thrust or concussion Athat occurs during the passage of atrain of cars.

The cylindrical blocks of the top stringers are provided with brackets (Z) through which diagonal holes (m, n) are made for the insertion'of diagonal screw rods laterally connecting the tops of two trusses. These trusses Vare kept apart laterally by tubular braces crossing the bridge at right angles and resting against the beveled surfaces of the bracket (Z). Shoes (ce) are arranged across the bottom chords, provided with grooves into which the chords fit. The

The floor beams (fu) are placed on and bolted to the shoe by means of bolts and form the lateral fastening at the bottoni of the trusses.

What VI claim as my invention and desire to secure by Letters'Patent is- 1. The flexile curved splice in the lower chord when said splice is formed of broad flat plates c,V o', b, b, with lateral curved offsets or lugs 0'", 6', formed on their ends; said olsets pulling against one another and allowing a free independent movement of each plate in the path of a vertical circle, substantially as set forth.

2. The combination of the convex or arched surface of blocks (l, la, s, e, al', c', os, with similarly convex or concave flanges t, at the ends of the tubular braces 0, and a, substantially as and for the purposes set forth.

3. The metallic clamps or recessed blocks d, c, d', c', for retaining and holding together the tension joints of the upper and lower chords or stringers in the manner and for the purposes set forth.

4. The grooved shoe w, which connects JONATHAN L. JONES.

lVitnesses:

CHAs. H. TILLSON, THOMAS P. HEWETT.

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