Patent Application
20240240453
Concrete has been in widespread use for a variety of surfaces, including roads and walkways. Given that concrete is a generally porous material and is exposed to changing weather conditions, expansion joints between sections or slabs of concrete accommodate expansion and contraction of the concrete. Many expansion joints include an insert or filler within the space between the sections or slabs of concrete. Traditional expansion joint inserts were made using materials such as wood, paper and asphalt. More recently, recycled rubber expansion joint inserts were introduced.
A concrete expansion joint insert includes a body having a length between a first end and a second end, a thickness between a first side and a second side, and a height between a first edge and a second edge. The body includes a first portion having the thickness, the length, and a first amount of the height. The body includes a second portion having the thickness, the length and a second amount of the height. The first portion of the body is predisposed to be separable from the second portion of the body. A separation support member is situated within the first portion along a substantial portion of the length.
In an example embodiment having at least one of the features of the concrete expansion joint insert of the previous paragraph, the second amount of the height is larger than the first amount of the height.
In an example embodiment having at least one of the features of the concrete expansion joint insert of any of the previous paragraphs, the separation support member comprises a metal wire.
In an example embodiment having at least one of the features of the concrete expansion joint insert of any of the previous paragraphs, the separation support member comprises a polymer material.
In an example embodiment having at least one of the features of the concrete expansion joint insert of any of the previous paragraphs, the separation support member includes a segment that at least partially extends out of at least one of the first and second ends.
In an example embodiment having at least one of the features of the concrete expansion joint insert of any of the previous paragraphs, the first portion is configured to be separated from the second portion upon applying a force on the segment of the separation support member.
In an example embodiment having at least one of the features of the concrete expansion joint insert of any of the previous paragraphs, the body includes a separation feature along at least a portion of an interface between the first portion and the second portion.
In an example embodiment having at least one of the features of the concrete expansion joint insert of any of the previous paragraphs, the separation feature comprises at least one of: a perforation, a weakness, a deformation, a stress concentration, or a reduced thickness.
In an example embodiment having at least one of the features of the concrete expansion joint insert of any of the previous paragraphs, the body comprises recycled rubber.
A method of making a concrete expansion joint insert includes forming a body comprising a first material; including a separation support member within a portion of the body, the separation support member comprising a second material that is different from the first material; and predisposing the portion of the body to be separable from a remainder of the body.
In an example embodiment having at least one of the features of the method of the previous paragraph, the including comprises situating the separation support member along at least a substantial length of the portion of the body.
In an example embodiment having at least one of the features of the method of any of the previous paragraphs, the separation support member comprises a wire.
In an example embodiment having at least one of the features of the method of any of the previous paragraphs, the including comprises including the second material in the forming such that the second material extends along at least a substantial length of the portion, the first material comprises recycled rubber, and the second material comprises a polymer.
In an example embodiment having at least one of the features of the method of any of the previous paragraphs, the second material has a melting temperature that is higher than a melting temperature of the first material.
The various features and advantages of at least one disclosed example embodiment will become apparent to those skilled in the art from the following description. The drawings that accompany the detailed description can be briefly described as follows.
The insert 20 is made or formed with the height H and thickness T. The insert 20 may be premade at the length L or be cut to length to establish the length L.
In some examples, the height H varies between two inches and twelve inches. Many concrete installations include slabs that have a thickness on the order of 3.5 inches, 4 inches or 6 inches. The height H is selected to correspond to the thickness of the concrete in such examples.
The thickness T may vary between 0.25 inches and 1 inch. Many expansion joints have a gap size of approximately one-half inch and the insert 20 will have a thickness T of one-half inch for such installations.
The insert 20 may comprise various materials. In some examples, the insert comprises recycled rubber. In other embodiments the insert comprises one of: wood fibers impregnated with asphalt, asphalt with minerals such as sand added between two layers of tar paper, recycled newspaper bonded under pressure and containing wax, recycled vinyl, cork, rebounded rubber, or neoprene and wood strips.
The body includes a separation feature 42 that is configured to facilitate separation of a first portion 44, which extends between the separation feature 42 and the edge 38, from a second portion 46, which extends between the separation feature 42 and the edge 40. As shown in
The separation feature 42 is established in the material of the body of the insert 20 without introducing any other material between the first portion 44 and the second portion 46. The separation feature 42 in the illustrated example embodiment includes a perforated segment of the material of the body of the insert 20. In other embodiments, the separation feature 42 includes a weakness or stress concentration in the material of the body of the insert 20, such as recycled rubber. In other embodiments, the separation feature 42 includes a deformation or a reduced thickness of the body material of the insert 20 along the interface between the first portion 44 and the second portion 46.
In some examples, as shown in
The separation support member 28 member is situated within the first portion 44 along a substantial portion of the length L to facilitate separating the first portion 44 from the second portion 46. In one example, the separation support member 28 includes a segment 48 that at least partially extends out of at least one of the ends 30, 32. An individual can grasp the segment 48 by hand or with a tool and begin to pull the first portion 44 away from the second portion 46 by applying a force F as schematically shown in
The separation support member 28 provides reinforcement and support within the first portion 44 to prevent first portion 44 from breaking into segments as the first portion 44 is manipulated to separate the first portion 44 from the second portion 46. A thin layer of recycled rubber material, such as the first portion 44, has a tendency to break in segments during a pulling movement like that shown in
With the separation feature 42 along the interface between the first portion 44 and the second portion 46, the first portion 44 is predisposed to be separable from the second portion 46. With the separation support member 28 in place, the first portion 44 is removed in one piece along the entire length L. As shown in
At 110, during the forming process, the separation support member 28 is included within the first portion 44 of the body. The separation support member 28 comprises a second material that is different from the first material. The second material has a melting temperature that is higher than the melting temperature of the first material. The second material is capable of retaining or establishing a desired shape of the separation support member 28 at temperatures up to 500° F.
In some examples, the separation support member 28 is preformed, such as a wire or thread, and inserted into the die while the first material of the insert body is extruded through the die. In one embodiment, an end of a wire or thread on a spool is introduced into the material of the body of the insert, such as melted resin and rubber, as that material flows through an extrusion die. The material carries the wire or thread through the die in a manner that the wire or thread continues to be fed into the die from the spool (or other supply) and situated within the first portion 44 as shown in
In one example embodiment, the separation support member 28 is a metal wire. Copper is used in some embodiments. Other example wires comprise steel or aluminum. In some embodiments, the wire is the type that is useful for electrical discharge machining (EDM).
In another example, the separation support member 28 comprises a polymer material, such as a high strength nylon. Some embodiments include a thread, cord or strand of polymer material that is strong enough to resist breaking while the first portion 44 is pulled away from the second portion 46. High tensile strength, no-break polymer strands or cords are included in some embodiments.
In some embodiments, the polymer separation support member 28 is formed while making the body of the insert 20 and the portions of the method shown at 100 and 110 in
In an example embodiment, the material of the body of the insert 20 comprises recycled rubber and a resin. The separation support member 28 is formed by extruding or otherwise introducing the resin (without being mixed with the rubber) through a high heat tube that directs the resin into the flow of the rubber and resin material while the body of the insert 20 is being formed. As the body material flows through an extrusion die, for example, the polymer resin occupies a part of the cross-section of the first portion 44 along the length of the insert 20 to establish the separation support member 28. Once the material of the body and the polymer material of the separation support member 28 cure, the separation support member 28 has the tensile strength and stability needed to support the first portion 44 during separation from the second portion 46.
At 120, the separation feature 42 is established along the interface between the first portion 44 and the second portion 46. In some embodiments, a blade cuts a slit in at least one of the sides 34, 36 along the length L of the body of the insert 20. The blade may penetrate into the body far enough to result in a cut that will facilitate separating the first portion 44 from the second portion 46 while still leaving enough of a connection between those portions so the insert 20 is stable during shipment, handling and installation.
One example arrangement for cutting a slit to establish the separation feature 42 includes a first oscillating saw blade situated to cut into the side 34 and a second oscillating saw blade situated to cut into the side 36. That arrangement includes a support, such as a conveyor or a set of rollers, for passing the formed and cooled insert 20 through the space including the oscillating saw blades.
In other embodiments, a perforating wheel engages at least one of the sides 34, 36 to establish a perforation along the interface between the first portion 44 and the second portion 46.
The disclosed example embodiments and others like them include a concrete expansion joint insert having a tab or portion that can be pulled out of the joint between two slabs of concrete. With a separation support member, such as those described above, the insert can be made of a variety of materials and the tab or portion that is separated from the rest of the insert without breaking during separation.
The preceding description is exemplary rather than limiting in nature. Variations and modifications to the disclosed examples may become apparent to those skilled in the art that do not necessarily depart from the essence of this invention. The scope of legal protection given to this invention can only be determined by studying the following claims.
