A screen for use in anchoring

Abstract: A screen (10) for anchoring a fastener (12) to a hollow block or brick wall (22) includes an elongate tubular plastic screen member (10) having first (28) and second (30) opposite ends and a uniform diameter along its length. The first end (28) is formed substantially into a frusto-conical shape that includes at least a portion (28A) thereof where the mesh of the screen is closed off. At least one reinforcement member (36, 36A) is formed along the length of the elongate screen member (10) that enables the elongate screen member to be inserted within a first aperture (14) formed in a first wall of a hollow block (22) and maintain the desired stiffness of the tubular screen member (10) so that it can extend across an interior of the hollow block (22) for blind insertion into a second aperture (16) formed in a second opposite wall of the hollow block (22).

Description: This invention relates generally to methods for securing a fastener to a hollow block or brick wall, and more particularly, to a screen which is filled with an adhesive and inserted within aligned apertures formed in the hollow block, brick or combination of common building practices. The fastener, such as a threaded bolt, rebar or smooth dowel rod, is inserted within the screen and extrudes the adhesive out of the mesh of the screen to bond with the hollow block and secure the bolt thereto upon setting. In order to securely attach a threaded rod, bolt, rebar or other fastener to a masonry wall, typically made of brick or hollow block, and provide dosage control for an adhesive, a metal screen illustrated in Figure 3 typically is utilized. The screen also can be used for brick pinning and with unreinforced masonry walls. To install the fastener and screen, a pair of aligned apertures are drilled through the opposing surfaces of the hollow block. The metal screen then is filled with an adhesive and inserted within both apertures and across the interior of the hollow block. The threaded rod or bolt then is inserted within the screen which extrudes the adhesive through the screen mesh with a "mushroom" effect to bond with the surfaces of the block. The screen typically is made of metal mesh and is either plated with zinc or made of stainless steel to reduce corrosion of the metal. To form the distal, insertion end of such a metal screen, portions of the mesh are tucked, folded over and spot welded in place. To assist in gripping the metal screen, a separate metal mesh tab is spot welded to the proximal end opposite the distal end. US 4968185 discloses such a metal mesh sleeve having a closed end and a longitudinal seam. US 4790114, also discloses a metal mesh sleeve, and alternatively suggests that the sleeve may be formed from a plastics or metal sheet material having holes, perforations, slots or foraminous openings for extruding the adhesive. Such metal screens, however, are difficult and expensive to make and are messy to fill and install. Additionally, despite measures to prevent corrosion, such metal screens still tend to corrode and/or react with the adhesive over time and discolour the front of the wall over time. Corrosion of the metal screen tends to expand the screen and crack the adhesive thereby reducing the pull out strength of the resulting anchor. According to a first aspect of this invention, a screen for filling with adhesive for anchoring a fastener to a hollow block, brick wall or other solid structure comprises: an elongate tubular screen member having first and second opposite ends and a uniform diameter along its length, said first end being formed substantially into a frusto-conical shape that includes at least a portion thereof where the mesh of the screen is closed off; at least one reinforcement member formed along the length of said elongate screen member that enables said elongate screen member to be inserted within a first aperture formed in a first wall of the hollow block and maintain the desired stiffness of the tubular screen member so that it can extend across an interior of the hollow block for blind insertion into a second aperture formed in a second opposite wall of the hollow block and is characterised in that; the screen member is formed from plastic mesh; and wherein said reinforcement member is formed as a helical seam along the length of the elongate screen member. According to a second aspect of this invention, a method of making a screen for anchoring a fastener to a hollow block or brick wall, comprises the steps of: (a) providing a strip of mesh having a predetermined length, width and mesh size; (b) forming said strip into a tubular member; (c) securing edge seams of said tubular member; and (d) heating one end of said tubular member and inserting said end into a die to form said end into a desired shape characterised in that the mesh is formed from plastic and the tubular member is formed by helically winding said strip. In accordance with this invention a screen for anchoring a fastener to a hollow block, brick wall or the like with an adhesive includes an elongate tubular screen member formed of plastic which is rigid enough to be inserted within the opposing apertures of the hollow masonry and does not corrode or reduce the effectiveness of the anchor over time while significantly reducing the cost of the screen and providing an easy clean installation. The screen can also be utilized in a solid wall or in just the face of a hollow block. Additionally, a thin plastic film of shrink wrap or heat-sealed material can be provided around the exterior of the screen to reduce mess during filling by a user and provide the correct amount of fill for the tubular screen for a particular application. The plastic film is removed using, for example a pull tab, by a user prior to insertion of the screen within the aperture. Embodiments of screens and their manufacture in accordance with this invention will now be described with reference to the accompanying drawings, in which:- Figure 1 is a perspective view of the plastic screen of the invention illustrated extended across the interior of a hollow block with adhesive and a threaded bolt secured therein; Figure 2 is a perspective view, in partial section, of the plastic screen of Figure 1; Figure 3 is an enlarged side elevational view of a prior art metal screen; Figure 4 is a perspective view of a plastic screen of the invention being rolled and secured into the desired shape; Figure 5 is an enlarged perspective view of the plastic screen of the invention illustrating the frusto-conical insertion end thereof; Figure 6 is a cross-sectional view of the plastic screen taken along line 6-6 of Figure 5 in the direction indicated; Figure 7 is a perspective view illustrating rolling and securing the plastic screen of the present invention; and Figure 8 is a perspective view of the thin plastic film that provides correct filling of adhesive in the screen and allows grabbing of the tubular screen prior to installation of the screen without mess. Referring to Figure 1, a plastic screen of the invention is designated generally by the reference numeral 10. The screen 10 preferably is utilized for securing a threaded bolt 12 within first and second apertures 14 and 16 formed in opposing first and second walls 18 and 20 of a hollow block, brick or other type of building structure 22 with an adhesive 23. If desired, the screen 10 also can be formed long enough to extend through an aperture 24 of a brick facing layer 26. It is to be noted, however, that the brick layer 26 can be removed or replaced with any other member so long as the screen 10 functions as described herein. The screen 10 preferably is formed from a synthetic fabric or mesh netting, such as nylon polyester, polypropylene or any similar material. Alternatively, the screen 10 can be formed from a perforated plastic sheet and may be made from polyester, polyethylene or polypropylene. Preferably, the screen 10 has a mesh opening of .0280 inches (0.7 mm) with 45% open area, a thread diameter of 350 microns and a fabric thickness of 700 microns, but can vary so long as it functions as described herein. The screen 10 has a predetermined diameter selected to co-operate with the diameter of the threaded bolt 12 and the apertures 14 and 16. The length of the screen 10 is selected so that at least a portion of the screen 10 extends outward from the second rear wall 20 of the block 22 where the length can vary depending on the size of the block 22 and whether a solid wall or face is utilized. As Figure 2 illustrates, the screen 10 includes a first closed distal end 28 and a second opposite open proximal end 30. The first end 28 preferably is substantially frusto-conical in shape to assist in insertion and prevents end loading when contacting the edge of the aperture 24. Alternatively, the first end 28 can be bullet or hemisphere shaped. To assist in gripping the screen 10 as adhesive is provided therein, the second end 30 includes an integrally formed plastic mesh tab 32. Alternatively, the tab 32 can be a separate member attached to the screen 10 or can be eliminated, depending on the application, particularly where flush installation is desired. Briefly, as Figure 4 illustrates, in the preferred method of making the screen 10, a strip 34 of screen having a predetermined length and width is cut from stock with the tab 32 extending therefrom. The strip 34 is rolled about its longitudinal axis and secured to itself at one or more locations, or along the entire length of the strip 34, by an adhesive, hot melt, or heat or ultrasonic welding. Alternatively, the screen 10 can be manufactured in a continuous operation. As Figure 6 illustrates, the welding or joining substantially provides a solid weld line 36 of melted material down the entire length of the screen 10. The solid weld line 36 improves the rigidity of the screen 10 to prevent buckling and assist in locating the screen 10 within the blind aperture 16 in the rear wall 20 of the block 22. If desired, additional weld lines (not illustrated) can be provided to further increase the rigidity of the screen 10. As Figure 5 illustrates, when the first end 28 is closed, the first end 28 is heated and formed within a die (not illustrated) to provide the frusto-conical, bullet or hemisphere shape and the closed mesh portion 28a as illustrated which may not close the entire first end 28. The screen 10 then is ready for use. Additionally, a separate plug (not illustrated) can be utilized to close off the first end 28. The simple method of manufacturing the screen 10 provides fast, low cost assembly with substantially smooth surfaces to eliminate edge loading during installation. The frusto-conical, bullet or hemisphere shape of the first end 28 provides ease of entry and trouble free insertion into the apertures 14 and 16. Figure 7 illustrates a method of manufacturing the screen 10. In this embodiment, the screen 10 is helically wound and welded or joined to provide a helical weld line 36a thereon. The helical weld line 36a provides the necessary rigidity to the screen 10 while enabling a strip 34 of the same width to be used to provide all diameters of the screen 10. More particularly, the screen 10 illustrated in Figure 7 has a diameter formed by winding the strip 34 at a particular pitch and providing the helical weld line 36a, such as by an adhesive, hot melt, or heat or ultrasonic welding. To change the diameter, the strip 34 merely is wound with a different pitch. Thus, one strip 34 can be utilized to provide screens 10 having a variety of diameters. Helically winding the screen 1 also can be accomplished in a continuous operation. To install the screen 10 and bolt 12 to the hollow block 22, the apertures 14 and 16 first are drilled into the first and second walls 18 and 20 of the hollow block 22. If the brick facing layer 26 is included, the aperture 24 also is drilled. The screen 10 then is held by the tab 32 and filled with adhesive 23. The conical end 28 of the screen 10 with the adhesive 23 therein is inserted through the apertures 26, 14 and 16 to the position illustrated in Figure 1. Alternatively, the screen 10 can be inserted within the wall and then filled with adhesive. The screen 10 also can be used with a single cavity within a wall. The bolt 12 is inserted within the screen 10 and adhesive 23 is extruded through the mesh of the screen 12. The adhesive 23 tends to accumulate about the surfaces of the first wall 18 and second wall 20 for adhesion thereto and the closed conical end portion 28a prevents adhesive 23 from flowing out of the end of the screen 10. Use of the plastic screen 10 provides a low cost method of manufacturing the screen 10 and securing the bolt 12 to the hollow block 22. The plastic screen 10 also reduces corrosion and is easier to locate in the apertures 14 and 16 due to the stiff weld line 36 and the conical end 28. Additionally, flow control of adhesive 23 along the length of the screen 10 can be provided by providing a label (not illustrated), which can be shrink wrapped, or by welding closed a portion of the plastic mesh at one or more desired locations (not illustrated). The label also can provide identification and instructions if desired. Additionally, Figure 8 discloses a thin piece of plastic film or extruded member 40, that could be used as a prophylactic and includes a pull tab 42. The film 40 is shrink wrapped or heat sealed together into the shape of a tube and is positioned about the screen 10 prior to insertion of the screen 10 into the aperture 24 to keep a user's hands free of adhesive during filling of the screen 10. Alternatively, the film member 40 can also be made of paper or a laminate material. The pull tab 42 assists in removal of the film 40 from the screen 10 and prevents insertion of the film 40 within the aperture 24 so that the film 40 is removed prior to installation of the screen 10. Additionally, a closed end 44 of the film 40 can be enlarged to assist in preventing insertion of the film 40 within the aperture 24.

Claims: A screen (10) for filling with adhesive for anchoring a fastener (12) to a hollow block, brick wall or other solid structure (22) comprising: an elongate tubular screen member (10) having first (28) and second (30) opposite ends and a uniform diameter along its length, said first (28) end being formed substantially into a frusto-conical shape that includes at least a portion thereof (28a) where the mesh of the screen is closed off; at least one reinforcement member (36, 36a) formed along the length of said elongate screen member (10) that enables said elongate screen member (10) to be inserted within a first aperture (14) formed in a first wall of the hollow block (22) and maintain the desired stiffness of the tubular screen member (10) so that it can extend across an interior of the hollow block for blind insertion into a second aperture (16) formed in a second opposite wall of the hollow block (22) characterised in that ; the screen member (10) is formed from plastic mesh; and wherein said reinforcement member is formed as a helical seam (36a) along the length of the elongate screen member (10). A screen as defined in claim 1, including a tab (32) integrally formed with said second opposite end (30) of said elongate screen member (10). A screen as defined in claim 1 or claim 2, wherein said closed portion (28a) of said conical first end (28) of said elongate member (10) is closed off by plastic which is provided by melting and forming said first end (28) into said frusto-conical shape. A screen as defined in any one of the preceding claims, including at least one portion along the length of said elongate member (10) which is blocked such that when the screen is filled with adhesive, adhesive is prevented from being emitted at that location. A screen as defined in any one of the preceding claims, including a member (40) including a pull tab (42) wherein the member (40) is positioned about at least a portion of said screen (10) for proper, easy filling of said screen with adhesive and clean installation of the screen after removal of the member (40). A screen as defined in any one of the preceding claims, wherein said screen member (10) is formed from a flat sheet of plastic mesh wherein two opposite edges of the sheet have been bonded together thereby forming said helical seam. A method of making a screen (10) for anchoring a fastener (12) to a hollow block or brick wall (22), comprising the steps of: (a) providing a strip of mesh having a predetermined length, width and mesh size; (b) forming said strip into a tubular member; (c) securing edge seams (36a) of said tubular member; and (d) heating one end (28) of said tubular member and inserting said end into a die to form said end into a desired shape characterised in that ; the mesh is formed from plastic and the tubular member is formed by helically winding said strip. A method as defined in claim 7, wherein said screen (10) is formed in a continuous operation. A method as defined in claim 7 or claim 8, wherein said step of securing edge seams (36a) includes forming a reinforcement member along the length of the screen (10).

Inventors: ERNST RICHARD J, KISH FREDERICK A, RANCICH MICHAEL J, TIMMERMAN MARK S, ERNST, RICHARD J., KISH, FREDERICK A., RANCICH, MICHAEL J., TIMMERMAN, MARK S.
Applicants: ILLINOIS TOOL WORKS, ILLINOIS TOOL WORKS INC.
Application year: 1995
Main classification: E04B1
IPC codes: E04G23, F16B13