Sealing Strip

Abstract

An elongated, tubular, sealing strip or member of resilient, flexible elastomeric material such as neoprene is provided with a top wall having a central portion formed as a V with a wide angle between the arms, and a pair of main reinforcing webs extending longitudinally within said tubular strip and respectively extending diagonally from the top wall of said strip adjacent one side edge thereof to the bottom wall of the strip adjacent the opposite side wall of the strip. Said reinforcing webs intersect and are joined together substantially at the intersection of an imaginary vertical plane equidistant from the side walls and an imaginary horizontal plane cutting the side walls at approximately their midpoints. Additional supplementary, reinforcing webs extend diagonally from approximately the midpoints of the side walls normal to the lower portions of the main webs.

Description

BACKGROUND OF THE INVENTION

This invention relates to the sealing of joints and is particularly concerned with the provision of a sealing strip to be used in pavement joints.

It has been found that expansion joints must be provided in concrete pavements and other extensive or massive concrete structures to allow expansion and contraction of the structure under varying temperature conditions without buckling or cracking. Such joints are formed, in a concrete pavement for example, as grooves molded between adjacent sections of pavement or as slots cut transversely at intervals along the length of the pavement. These grooves or slots must be sealed to prevent accumulation of dirt therein which would interfere with their function and to prevent the entrance of water which in cold weather may, in freezing, cause damage to the abutting pavement sections. It was long the practice to fill the grooves or slots with a caulking compound or a hardening liquid filler which was soft enough to yield when expansion occurred in the pavement. However, in general, such materials were failures because they lost their resiliency or flexibility in cold weather so that they cracked or pulled away from the sides of the groove or slot allowing entrance of water and consequent damage to the pavement. Attempts have been made to replace these sealing compounds with preformed, resilient elastomer sealing strips which are inserted in the joint and maintain a sealing relationship at all times. There have been many designs for such strips but few of these designs have been satisfactory since when they are subjected to stresses there is a tendency with many seals for the top edges of the side walls thereof to rotate or shift away from the adjacent faces of the pavement sections. Also, in some cases the sealing strip under compression in use shifts because of improper design and it may develop bulges that exert torque on the strip. If lighter construction is used to avoid such bulging, the resilient force necessary to maintain a good seal may not be obtainable.

SUMMARY OF THE INVENTION

The novel sealing strip of the present invention is advantageous because its design permits folding of the internal webs under compression without interference so that there is no bulging, because the internal reinforcing webs therein are so arranged as to maintain equalized support for the side walls during expansion and compression of the strip, and because it has a top wall which does not bulge or rise under compression so that there will be no chance for it to be affected by traffic passing thereover.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an end elevational view of a sealing strip manufactured according to the present invention, with no stress applied thereto;

FIG. 2 is a fragmentary plan view of the sealing strip shown in FIG. 1;

FIG. 3 is a fragmentary end elevational view of a pavement joint employing a sealing strip according to the present invention, the sealing strip being shown under compression;

FIG. 4 is a view similar to FIG. 3, but with the sealing strip shown under greater compression; and

FIGS. 5 and 6 are views similar to FIG. 1 but illustrating modifications.

DESCRIPTION OF A PREFERRED EMBODIMENT

From the drawings it will be understood that the novel sealing strip shown in FIGS. 1 - 4, inclusive, and comprehensively identified by the numeral 11, is an elongated and essentially hollow, tubular member. It comprises a generally horizontal top wall 13, vertical side walls 15 and 17, which at their upper edges are attached to the edges of the top wall 13, and a bottom wall 19 attached to the lower edges of the side walls 15 and 17. Preferably, the sealing strip is formed by extrusion, according to known procedures, of a suitable elastomer. Consequently, it may vary in length as desired, but is generally made in long lengths, often of many hundreds of feet, and cut, in installation, to shorter lengths as necessary to fit the joints. The terms upper, lower, top, bottom, right, left, down, up, and similar terms of position or direction as used hereinafter, refer to the illustration in FIG. 1, but they are used only for convenience of description and should not be construed as limiting the scope of the present invention or as implying a necessary positioning of the structure or portions thereof.

Within the hollow, elongated body described above there are disposed elongated reinforcing webs or struts, as hereinafter described, to maintain the shape of the sealing strip and provide controlled resistance to horizontal compression thereof such as will occur in use. The top wall 13 of the strip is symmetrical longitudinally along its center line, each lateral half thereof comprising a border 23 extending inwardly from the side edge of the wall 13 normal to the adjacent one of the side walls 15 and 17 for a distance equal to approximately one-quarter of the total width of the top wall and an inner portion 15 inclined slightly downwardly, preferably at an angle of from about 5.degree. to about 20.degree.. Thus, in cross-section the central portion of the top wall 13 is in the shape of a downwardly pointed V with a large angle, preferably about 140.degree. to about 170.degree., of opening.

Extending diagonally inside the strip 11 from the border portions 23 of the top wall to the bottom wall 19 immediately adjacent the opposite side walls are a pair of main reinforcing webs 29, these webs intersecting and being joined together substantially at the intersection 31 of an imaginary vertical plane equi-distant from the sides of the strip 11 and an imaginary horizontal plane cutting the side walls 15 and 17 at approximately their midpoints. The ends of these diagonal webs are integrally attached to the top and bottom walls of the sealing strip adjacent to the side walls but spaced inwardly therefrom sufficiently to control movement of the strip side walls and to prevent buckling thereof as pressure is applied to the sides of the strip. The desired spacing will to some extent vary with the cross section of the strip.

Additional supplementary reinforcing webs or struts 33 extend diagonally in the strip 13 from approximately the midpoints of the side walls 15 and 17 to approximately the midpoints of the lower portions 35 of the main struts 29, being normal to said main struts or webs at the points of intersection therewith. All of the reinforcing webs extend longitudinally throughout the length of the strip 11 and are integral with each other and with the top, bottom, and side walls of the member 11 at their junctures therewith. The bottom wall 19, as shown in FIG. 1, is curved outwardly in cross section. The extent or degree of curvature may be varied, as hereinafter explained, to provide variation in the resistance of the strip to horizontal compression.

In FIG. 3 a sealing strip 11 according to the invention is shown in place between the end faces 40 of two concrete slabs 39 constituting a portion of a roadway or pavement, the strip being under partial compression as it would be when the slabs 39 are contracted as in cold weather. As will be observed, the central portion of top wall 13 has been depressed to form a deeper trough but the inner portions 25 of the top wall still exert pressure on the top edges of the side walls 15 and 17,thus preventing said edges from inward movement that might destroy sealing engagement with the slabs 39.

In FIG. 4, which is similar to FIG. 3, a sealing strip 11 is shown under further compression, such as would be obtained when the slabs are expanded in summer. It will be noted that even under this considerable compression, the top wall 13 of the sealing strip does not bulge above the pavement surface and that the side walls 15 and 17 of the strip are pressed against the opposing faces 40 of the slabs without vertical displacement of said walls. As will be seen in FIG. 4, the webs 33 do not bulge as compression is applied, but fold so that the main webs are supported and exert pressure to maintain the seal in place.

In installing the novel sealing strip of the present invention in a pavement joint, conventional practice can be employed. Briefly, a coating of a suitable adhesive, which also serves as a lubricant during installation of the seal, is applied to each of the end faces of the adjacent concrete slabs and/or the sides 15 and 17. Then, preferably by use of a suitable machine such as are commerically available, the sealing strip is compressed laterally and pushed down in the slot between the slabs. The strips or seals are customarily supplied in long rolls which are carried by the machine and fed into the joint as the machine advances along the length of the joint. The extent to which the sealing strip is compressed during installation will vary according to the width of the joint and the extent to which the slabs 39 are expanded. The latter, of course, depends upon the temperature of the slabs and the coefficient of thermal expansion thereof. In general, to ensure good results, the compression of the strip as installed should be a minimum of about 20 percent. It should be understood that sealing strips according to the present invention may be, as is customary, made in a variety of sizes. Thus, the compression necessary to ensure continued proper sealing between slabs will be attainable regardless of the spacing between the slabs.

While the sealing strip illustrated in FIG. 1 has a convex bottom wall 19, it will be understood that the curvature of the wall 19 may be increased or decreased, or even reversed, within the scope of the present invention. This is illustrated in FIGS. 5 and 6. In FIG. 5 the structure is identical with that shown in FIG. 1 except that the bottom wall 19' of the sealing strip is substantially straight. The result of such construction is to put slightly more pressure against the side walls 15 and 17 at the lower ends thereof when the strip is in place, thereby holding the strip more tightly against displacement.

In FIG. 6 the structure is identical with that shown in FIG. 1 except that the bottom wall 19" of the sealing strip is slightly concave and the side walls 15' and 17' are provided on their exterior faces with a plurality of longitudinally extending parallel ribs 42. The concave bottom wall permits application of still more stabilizing force against the side walls as the strip is compressed. The ribs 42 on the side walls serve to trap or collect adhesive in the intervening grooves to assist in providing a water-tight seal. It will be understood that the employment of such ribbed side walls is a matter of choice depending upon the materials used and the conditions of use and that such walls may be used with the embodiments shown in FIGS. 1 and 5, if desired.

Although sealing strips in accordance with the present invention may be constructed of a number of flexible, resilient, elastomeric materials, it is preferred to employ strips formed of a neoprene composition which retains its flexibility and resilience throughout a wide temperature range. Such materials are available in commerce and may be readily extruded as tubing having the novel structure hereinabove described. The adhesive-lubricant composition used is preferably air setting and should, of course, bond well with both the concrete slabs and the sealing strip employed. Adhesives suitable for such purpose are well known.

It is evident that the present novel sealing strip is useful and efficient since it maintains a sealing relation between adjoining bodies at various stages of compression and is not easily displaced. The working life of the strip will be prolonged, even under severe working conditions because of the controlled folding of the webs and the web stress control characteristic of the design. It will be understood that such sealing strips may be employed not only in sealing joints in pavements, bridges, and the like, but also in buildings, piers, and other concrete or masonry structures.

It will be understood that the foregoing specific description and the accompanying drawings are merely exemplary of the present invention and that various modifications and alterations in the sturctures shown and described may be made without departing from the spirit of the invention.

Claims

I claim:

1. A flexible, resilient, sealing strip adaptd for sealing a slot between adjacent faces of rigid bodies and maintaining a sealing relation during changes in width of said slot resulting from expansion and contraction of said bodies which comprises: an elongated, tubular member having spaced side walls that are approximately straight and parallel; a top wall joining the upper edges of said side walls, said top wall having edge portions substantially normal to said side walls and an inner, central portion having in cross-section a downwardly pointed V-shape; a bottom wall joining the lower edges of said side walls; a pair of elongated ,intersecting, main reinforcing webs within said tubular member, each of said main webs extending diagonally from one of said normal portions of said top wall to said bottom wall adjacent the opposite side wall and intersecting substantially at the intersection of a vertical plane equidistant from the side walls of said strip and a horizontal plane cutting said side walls at their mid-points; and a pair of elongated supplementary reinforcing webs within said tubular member, each of said supplementary webs extending diagonally downward from an intermediate point on one of said side walls to the adjacent main web only, said strip being free from webs in the space between said main webs and below the intersection of said main webs.

2. A sealing strip as set forth in claim 1 in which said walls and said reinforcing webs are integral and said reinforcing webs extend throughout the length of said strip.

3. A sealing strip as set forth in claim 2 in which each of said supplementary webs is normal to said adjacent main web.

4. A sealing strip as set forth in claim 2 in which said main webs join said bottom wall immediately adjacent said side walls.

5. A sealing strip as set forth in claim 2 in which the angle of the V of said central portion of said top wall is between about 140.degree. and about 170.degree..

6. A sealing strip as set forth in claim 4 in which said bottom wall is convex.

7. A sealing strip as set forth in claim 4 in which said bottom wall is straight and substantially normal to said side walls.

8. A sealing strip as set forth in claim 4 in which said bottom wall is concave.

9. A sealing strip as set forth in claim 2 in which said bottom wall is convex.

10. A sealing strip as set forth in claim 2 in which said bottom wall is straight and substantially normal to said side walls.

11. A sealing strip as set forth in claim 2 in which said bottom wall is concave.

12. A sealing strip as set forth in claim 9 in which the angle of the V of said central portion of said top wall is between about 140.degree. and about 170.degree..

13. A sealing strip as set forth in claim 10 in which the angle of the V of said central portion of said top wall is between about 140.degree. and about 170.degree..

14. A sealing strip as set forth in claim 11 in which the angle of the V of said central portion of said top wall is between about 140.degree. and about 170.degree..

15. A sealing strip as set forth in claim 3 in which said bottom wall is convex.

16. A sealing strip as set forth in claim 3 in which said bottom wall is straight and substantially normal to said side walls.

17. A sealing strip as set forth in claim 3 in which said bottom wall is concave.