US2125220A - Method and apparatus for shortening bridge structural members or the like - Google Patents

Description

July 26, H COLWELL METHOD AND APPARATUS FOR SHORTENING BRIDGE STRUCTURAL MEMBERS OR THE LIKE Filed Aug. 12, 1936 Patent ed July 26, 1938 PATENT OFFICE METHOD AND APPARATUS FOR SHORTEN- ING BRIDGE STRUCTURAL MEMBERS OR THE LIKE Harry R. Colwell, Kitanning, Pa.

Application August 12, 1936, Serial No. 95,723

1 Claim.

The present invention pertains to a method of repairing by tightening and realigning, bridges but it will appear from the hereinafter following description that the invention is not necessarily 5 limited to use in connection with bridges but can be used for the purpose of shortening any metallic structural member.

Many rivers, streams and creeks in this country are spanned by iron bridges of socalled rigid types. Bridges of this type in the course of time loosen up, sag and become unaligned due to loosening and sagging. As a consequence these bridges must be overhauled from time to time and reconditioned. In the past the matter of overhauling a bridge has been a tedious and expensive undertaking due to the methods employed.

The present invention has as its primary object the provision of an improved method of overhauling bridges which will enable the work to be done rapidly and cheaply and will not in any way interfere with the normal traffic passing over the bridge.

Iron bridges are made up of a plurality of I bars or beams, some of which are horizontally disposed while others are vertically disposed or disposed at an inclination to the vertical. It is due to the stretching or loosening of these bars that the bridge sags or becomes sufficiently loose to need overhauling. By shortening the proper bars the proper amount the bridge can be tightened and placed in proper alignment.

In. the past methods have been practiced for shortening the bridge structural members, but these methods have all been objectionable for one reason or another. In respect to all methods heretofore used and known to me they have been objectionable from the standpoint of expense and have been objectionable because in shortening the bridge beams they have been cut intermediate their ends which results in weakening the bridge structure. It is not considered necessary to point out in detail why the methods heretofore practiced have been expensive, but it is thought sufficient to state that my present method overcomes the objections inherent in the older methods and thereby makes it possible to rapidly, efliciently and cheaply overhaul a bridge.

Although my present invention can be practiced in connection with structures other than bridges, I have in the following description elected to describe the invention as. used in connection with the I bar or beam of a bridge, but in reading the following description in the light of the accompanying drawing it is to be understood that the I bar referred to need not necessarily be a structural part of a bridge, but could be a structural element of any metallic structure.

In the drawing:

Figure l is a view in side elevation illustrating the apparatus at the time the structural element is about to be shortened.

Fig. 2 is a view in side elevation of the parts appearaing in Fig. l and illustrating their positions after the structural element has been shortened.

Fig. 3 is a view in end elevation of the parts as they appear in Fig. 1.

Fig. 4 is a longitudinal vertical sectional view taken on the line 44 of Fig. 1, looking in the direction indicated by arrows.

Fig. 5 is a transverse vertical sectional View taken on the line 55 of Fig. 2, looking in. the direction indicated by arrows.

Referring now to the drawing in which like parts are designated by similar reference letters and numerals throughout the description and from which an understanding of the application of the present improved invention to a bridge can be well understood, A designates an I bar or beam such as is commonly utilized and found in bridge structures. It is to be understood that this bar in the bridge might be either horizontally or vertically disposed or might extend at an angle to the vertical. This bar in its ends has eyes I for the reception of bolts or other suitable fastening means for securing together the adjacent ends of a pair of I bars or for securing the ends of the I bars to some other portion of the bridge structure.

In carrying out the present method, I utilize a clamp which is designated as an entirety at B and which will now be described in detail. It is to be recognized, first, that due to the weight of a bridge and the fact that its structural elements are of necessity very heavy, that the clamp will be of a weight, size and strength sufficiently adequate to accomplish the desired purpose, and, secondly, that in practicing the present improved method the clamp need not necessarily be built exactly in accordance with the clamp illustrated in the drawing and described hereinafter.

The clamp about to be described, however, has been found to be very efficient and describing the same in detail it will be seen that it comprises a pair of elongated bolts 2 and 3 having at their left hand ends nut heads 4 formed as a part of the bolts, while their opposite ends are threaded as at 5 to receive the nuts 6. The bolts 2 and 3 are held in separated parallel relationship by an enlargement which constitutes a head through which the bolt 2 loosely passes and that the member Y has a similar head 8 through which the bolt 3 loosely passes. The arm bridge portions 9 and H) parallel one another and are disposed on the opposite sides of the .flat I bar or beam A. The extreme ends H, and 12, of the arms 9 and Ill abut the inner faces of the heads 8 and '7 respectively. Bolts 13 and through the arms 9 and ID at points beyond the edges of the bar or beam A and serve as a means to clamp the arms tightly against the beam.

In carrying out the method protrusions or abutments are welded on the bars or beams A in separated relationship. The disposition of these protrusions or abutments appear clearly in the drawing, from which it will be seen that one, of them is, designated at R and R, R being the protrusion on one face of the bar and R being a protrusion disposed exactly opposite to it on the other face of the bar. The other protrusion or abutment is designated at S and S. It has been found that it has not been desirable to drill the bar and make the obstruction in the form of a rivet or bolt, because to do so would weaken the bar and consequently the protrusions are separate and distinct deposits suitably secured in place, preferably by welding.

In practicing the method the arms X and X of theclamp are placed at either side of the bar and abut the obstruction R and R at one side thereof. At a point intermediate the abutments RFR and S-S' the clamp arms Y and Y are positioned while at the far side of the abutment 8-8 the clamp arms Z and Z are positioned upon the bar, all of which is clearly illustrated in the drawing.

' To shorten the bar it remains now only to heat that portion 65 of the bar lying between the clamp arms X X and YY. Any suitable means can be utilized for heating the bar. I have found it convenient to use an acetylene torch, although it is readily recognized that other means of heating could be successfully utilized. When the bar has been locally heated to the desired temperature the nuts 6 are tightened down with the result that the heated parts of the bar is upset as indicated at E6 in. Fig. 2 of the drawing. It having been determined beforehand how much is to be shortened the clamps. are tightened down against the rod abutments until l4 pass the bar has been upset sufficiently to shorten it the required and desired amount. I

The clamp arms Y and Y serve to localize the upset area of the bar and act as a guide as well as a strengthening medium to prevent the bar from twisting when longitudinal pressure is applied to the bar at the opposite sides of the abutments by the clamp arms X-X and ZZ'.

From the preceding description it will be seen that I have provided a simple and rapid yet an efiicient manner of shortening the structural elements of a bridge. The bridge elements can be operated upon within a few minutes and without interruption to traffic and without in any degree whatsoever weakening the bridge as has been the case in respect to the methods heretofore practiced. The bridge elements can be operated upon while they remain in place which, of course, effects a great saving in time andlabor and expense. Additionally; the bridge can be overhauled and tightened without building any support structure from beneath the bridge to lift the bridge sag as has been necessary in connection with many of the methods heretofore practiced. Sumcient pressure can be brought to bear through the medium of the clamps to shorten the desired bridge bar elements to remove all of the sag from the bridge without the assistance of any supports from beneath the bridge and thus again save much time, labor and expense in making the necessary bridge repairs. 7

In the drawing and description I have illustrated and described in detail a preferred embodiment of my present improved invention, but it is to be understood that various changes, and modifications may be made therein within the scope of the appended claim.

Having thus described my invention. what I claim and desire to secure by Letters Patent is:.

A method of shortening supporting beams for bridges to take up the slack thereof without severing said beam. and without removing said beam from the bridge structure, which consists in forming on opposite sides of said beam pairs of projections located in alignment and separated sufficiently to enable said beam to be heated between said pairs of projections and upset to take up said slack, applying adjustable clamping and supporting members to the beam longitudinally and at opposite sides thereof, said clamping members engaging the beam outwardly of said projections, heating said beam between said projections and drawing or adjusting said clamping members into engagement with said projections and towards each other sufficiently to take up said slack while the beam is softened by said heating, said clamping and supporting members holding the beam until the heated and softened portion has hardened.

HARRY R. COLWELL.

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