Installation of concrete fasteners using low-viscosity adhesives

Abstract

A method for attaching a fastener to a substrate, the fastener comprising a shank having a first end and a second end defining a length, a head at the second end, and threads on the shank including leading and trailing ends adapted to remove a portion of the substrate when inserted into the substrate. The method includes forming a hole having a diameter that is the nominal shank diameter of the fastener to be attached to the substrate. The hole is then filled with an adhesive having a viscosity of 350 cP or less. Finally, the fastener is rotated into the hole such that when the threads are fully inserted into the hole, the adhesive is forced into the portion of the substrate adjacent the shank and the threads.

Description

Technical Field

[0001] (Priority) This application claims the priority of U.S. Patent Application No. 17 / 491,342, titled "CONCRETE FASTENER INSTALLATION USING LOW VISCOSITY ADHESIVE", filed on September 30, 2021, which is hereby incorporated by reference in its entirety.

[0002] This technology relates to improvements in thread tapping fasteners, particularly concrete fasteners, and their installation.

Background Art

[0003] Thread tapping concrete screws are screwed into holes drilled in construction materials, particularly concrete, without using plugs. Usually, when the screw is being screwed in, the screw enters the construction material such that the screw taps or cuts a mating thread in the construction material. Therefore, the screw itself cuts the threads and mating threads required for a good fit between the screw and the construction material.

[0004] When a thread tapping screw is screwed into a drill hole, stone dust from the construction material is formed in the region of the end of the screw. This stone dust may occur because it was not completely removed from the drill hole after drilling and / or because stone dust is formed when the thread tapping screw is screwed into the drill hole in the region of the end of the screw.

[0005] Over time, cracks may occur in the attachment of fasteners to concrete, which can be repaired with an adhesive, and there have been fasteners that were attached using an adhesive in the past.

Summary of the Invention

[0006] This specification describes a method for attaching a fastener to a substrate. The fastener comprises a shank having a first end and a second end that define its length, a head provided at the second end, and a thread provided on the shank, including a front end and a rear end adapted to remove a portion of the substrate when inserted into the substrate. The method includes forming a hole having a diameter that is the nominal diameter of the shank of the fastener to be attached to the substrate. The hole is then filled with an adhesive having a viscosity of 350 cP or less. Finally, the fastener is rotated toward the hole so that the adhesive is pressed into the portion of the substrate adjacent to the shank and the thread when the thread is fully inserted into the hole.

[0007] The fastening structure will also be explained. The structure consists of a base material, a hole having a diameter that is the nominal diameter of the shank of the fastener to be attached to the base material, and within the base material hole The fastener comprises an internal fastener. The fastener comprises a shank having a first end and a second end that define the length, a head provided at the second end and adjacent to the upper surface of the base material, and a thread provided on the shank, including a front end and a rear end adapted to remove a portion of the base material when inserted into the base material, the thread is hole It is embedded in the substrate along its length. An adhesive with an attachment viscosity of 350 cP or less is used. hole It is embedded in the wall portion and in the substrate adjacent to the threads of the embedded fastener.

[0008] This summary is provided to simplify some of the concepts described later in the detailed explanation. This summary is not intended to identify the main or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. [Brief explanation of the drawing]

[0009] [Figure 1] This is a plan view of a concrete fastener 100 that is attached to a pilot hole drilled in concrete.

[0010] [Figure 2] It is a flowchart showing a method for attaching a fastener as shown in FIG. 1.

[0011] [Figure 3] It is a partial cross-sectional view showing the steps of the method for attaching the fastener of FIG. 2.

[0012] [Figure 4] It is a partial cross-sectional view showing the steps of the method for attaching the fastener of FIG. 2.

[0013] ]> [Figure 5] It is a partial cross-sectional view showing the steps of the method for attaching the fastener of FIG. 2.

[0014] [Figure 6] It is a partial cross-sectional view showing the steps of the method for attaching the fastener of FIG. 2.

[0015] [Figure 7] It is a partial cross-sectional view showing the steps of the method for attaching the fastener of FIG. 2.

[0016] [Figure 8] It is a sequence showing the influence of the withdrawal force over time on the fastener disclosed in FIG. 1.

[0017] [Figure 9] It is a flowchart showing a method for attaching a fastener as shown in FIG. 1.

[0018] [Figure 10] It is a partial cross-sectional view showing the steps of the method for attaching the fastener of FIG. 9.

[0019] [Figure 11] It is a partial cross-sectional view showing the steps of the method for attaching the fastener of FIG. 9.

[0020] [Figure 12]It is a partial cross-sectional view showing the steps of the method for attaching the fastener of FIG. 9.

[0021] [Figure 13] It is a crack cycle graph of the fastener of FIG. 1 attached using the method of FIG. 2.

[0022] [Figure 14] It is a crack cycle graph of the fastener of FIG. 1 attached using the method of FIG. 9.

[0023] [Figure 15] It is a step-by-step crack cycle graph comparing the attachment of the fastener of FIG. 1 with the attachment of the fastener of Application No. 17 / 246,247 attached using the methods of FIGS. 2 and 9.

Embodiments for Carrying Out the Invention

[0024] An improvement in the method of attaching a fastener to a substrate will be described. The fastener includes a shank and a thread provided on the shank, and the thread includes a front end and a rear end adapted to remove a part of the substrate when inserted into the substrate. This method includes the step of forming a hole having a diameter that is the nominal diameter of the shank of the fastener to be attached to the substrate. Next, the hole is filled with an adhesive having a viscosity of 350 cP or less, and in one embodiment, 150 cP or less, and the fastener is rotated into the hole so that when the thread is fully inserted into the hole, the adhesive is pushed into the part of the substrate adjacent to the shank and the thread.

[0025] FIG. 1 is a plan view of a concrete fastener 100 attached in a pilot hole drilled in concrete.

[0026] The fastener 100 has a fastener head consisting of a nut 130 and a washer 132 at one end of the fastener shank 140. The fastener shank 140 is provided with threads 127. The shank 140 has a portion 155 that is composed without threads 127. This portion 155 transitions into the washer 132 and nut 130 at 135 and becomes integrated. The shank 140 has the outer diameter D1 of the threads 127, as well as the root diameter or nominal diameter D2 of the fastener shank 5. The threads 127 also have a pitch P corresponding to the distance between any two bends of the threads 127. The fastener 100 is inserted into a pre-drilled hole having a diameter the same as or slightly larger than the shank of the fastener.

[0027] The front section 127a of the fastener 100 begins at the fastener end 145 and extends toward the fastener head in the direction of the longitudinal axis CL of the fastener 100. In this embodiment, the front section 127a includes approximately two bends in the thread 127.

[0028] While the fastener 100 shown in Figure 1 is suitable for use with the present technology, any embodiment of the fastener disclosed in U.S. Patent Application No. 17 / 246,247, filed April 20, 2021, entitled "Concrete fastener," invented by Joel Hook, may be incorporated herein by reference in whole and used in accordance with the mounting techniques described herein.

[0029] Embodiments of fasteners of Patent Application No. 17 / 246,247 may include a fastener having a flat top thread, and / or a shank anti-rotation region, and / or a shank anti-rotation region of variable length, and / or a shank anti-rotation region of variable depth, and / or a thread having a first thread angle in a region adjacent to the tip or front end of the fastener, a second smaller thread angle in a region between the first thread angle and the second end of the fastener, and / or a thread having one or more cutting edges at the tip of the fastener, and / or a portion of the thread having a triangular lobe-shaped thread, and / or a novel serrated thread having a triangular front end followed by a conchoidal rear end, and / or a double lead thread at the tip of the fastener.

[0030] Figure 2 shows a method for installing either the fastener 100 of Figure 1 or an embodiment of the fastener shown in Patent Application No. 17 / 246,247. Figure 2 is described with reference to Figures 3 to 7, which are partial cross-sectional views showing the steps of the method for installing the fastener of Figure 2.

[0031] In step 210, the installer uses, for example, a carbide drill bit to drill into the substrate 300. hole The 302 is drilled, and the hole is made to have the same diameter as the nominal diameter of the fastener to be attached. hole 302 is a fastener and hole To contain thread tapping dust that cannot be removed by cleaning, it is drilled to a predetermined minimum hole depth. This is drilled by a drill bit 320 coupled to a drill chuck 330. hole Figure 3 shows a base material 300 having 302.

[0032] In the 220, for example, compressed air is used to clean the holes. This is shown in Figure 4. hole To blow away the fine particles from 302, holeA portion of a compressed air canister 340 having a cannula for forcing air into it is shown. Instead of step 220, or in addition to step 220, hole 302 can drill to a depth sufficient to accommodate the depth of the fastener and any dust resulting from drilling and tapping without forced air cleaning at 220. At 230, as illustrated in Figure 5, the brush 350 is, for example, hole By making the bus move back and forth and rotate within 302, hole 302 may be used for further cleaning. At 240, fastener 100 passes through fixing device 400. hole It is inserted into 302. Next, in step 250, as shown in Figure 6, the fastener is tightened to the base material using a power fastening tool. In step 250, the fastener is tightened to the base material 300 until the washer head portion of the fastener contacts the fixture 400, as shown in Figure 7.

[0033] Figure 8 shows four cross-sectional views of fastener 100 demonstrating the pull-out effect on a cracked concrete substrate when the fastener has an angled upper surface, illustrating four stages (labels 1 to 4 in each figure of Figure 8 indicate the effect of the pull-out force over time compared to the embodiment of the fastener disclosed in Figure 1).

[0034] In stage 1 of Figure 8, the fastener 100 is stationary within the concrete slab and is installed in a pilot hole. An external force acting on the concrete causes a crack to form, and the crack intersects with the position of the fastener. In stage 2 of Figure 8, when a pull-out force 602 acts on the fastener, a lateral force 604 acts due to the external force acting on the concrete, causing delamination from the fastener in the concrete slab. At this stage, combined with the pull-out force of the fastener, the angle of the thread crest causes the fastener to slide upward within the hole. As shown in stage 3, the pull-out force 602 remains constant due to the elasticity of the reinforcing steel embedded in the concrete and the removal of the external load, so the concrete returns towards the fastener. Since the fastener has already slid upward within the hole, as the concrete returns to its original position, it is slightly compressed at the thread crest. Note that in stage 3 of Figure 6, a slight delamination 610 begins to occur between the thread groove of the concrete slab and the thread of the fastener, and the strength of the fastener in the slab weakens. As time progresses, the peeling 610 expands, as shown in step 4 of Figure 6.

[0035] The technology of this disclosure helps to increase resistance to pull-out as described with respect to Figure 8.

[0036] Figure 9 shows a method for mounting either the fastener 100 of Figure 1 or an embodiment of the fastener illustrated in Patent Application No. 17 / 246,247, according to the present art. Figure 9 will be described with reference to Figures 3 to 5 and Figures 10 to 12, which are partial cross-sectional views showing the steps of the method for mounting the fastener of Figure 9.

[0037] In the method shown in Figure 9, steps 210, 220, and 230 are performed in the same manner as described above and illustrated in Figures 3 to 5. hole Before installing the fasteners inside, in 995, holeA low-viscosity adhesive is applied inside. In one embodiment, the adhesive may include a low-viscosity structural injection epoxy having a viscosity of 350 cP or less. For example, a two-component, high-modulus, high-solidity, moisture-resistant epoxy designed for pressure injection, gravity feeding, and floodcoat filling of concrete cracks, such as the CI-LV low-viscosity injection epoxy with a viscosity of 350 cP available from Simpson Strongtie, has been found effective in performing the installation method disclosed herein. In another embodiment, a CI-SLV ultra-low-viscosity injection epoxy with a viscosity of 150 cP, also available from Simpson Strongtie, may be used. As shown in Figure 10, the adhesive is applied using an injection gun 1010. hole It may be injected into 302.

[0038] Next, at 940, the fastener 100 contains adhesive. hole It is inserted and tightened at 945, within the gel time specific to the adhesive. A typical gel time for such an adhesive is about 40 minutes. During the tightening process, the adhesive hole The adhesive may overflow, and at 950, the excess adhesive needs to be removed. At 960, the adhesive should be allowed to cure before any load is applied to the fastener 400 fastened by the fastener 100.

[0039] As a result, 1200 of the adhesive hole The structure is lined with an interior. As shown in Figure 12, some of the adhesives are hole The bottom and hole It may penetrate into the concrete wall adjacent to the wall. Since low viscosity epoxy is typically suitable for repairing hairline cracks (0.002 inches) and cracks up to 1 / 4 inch (6 millimeters) wide, the low viscosity adhesives described herein are used for injection into cracks in structural concrete. When fasteners are installed using the low viscosity adhesive in the disclosed manner, the displaced adhesive will holeThe 302 material is pushed up against the wall, allowing it to penetrate the concrete and reinforce the surface where the fastener's threads engage. When cracks open and close in the concrete, the surface rubbing against the threads is much harder than the exposed concrete, resulting in less concrete fracturing. As a result, in this state, much higher performance is achieved than when no adhesive is used, as shown in the graph below.

[0040] Alternative adhesives may be used according to this method, and the amount of adhesive leakage or penetration into the concrete will vary depending on the composition of the adhesive. Thus, based on viscosity, hole There are three possible states for the adhesive within the device: that most or all of the adhesive penetrates the concrete, with the remainder filling part of the annular space between the thread shank and the concrete; that the adhesive fills the annular space between the fastener and the concrete, with some of it penetrating and reinforcing the concrete; and that the adhesive fills the annular space between the thread shank and the concrete, with no penetration into the concrete. Test results with various fasteners, some of which are described below, showed that the 150 cP adhesive used in the disclosed method performed better than the 350 cP adhesive; however, the 350 cP adhesive still improved the pull-out performance compared to fasteners installed without using this method. Adhesives with even lower viscosities than 150 cP can also be used in this method.

[0041] Figures 13 and 14 are crack cycle graphs of fastener displacement obtained by testing various mounting methods of the fastener shown in Figure 1 using an adhesive with a viscosity of 150 cP. Figure 13 shows the displacement of the fastener over numerous stress cycles when fastener 100 is mounted using the method in Figure 2, where no adhesive was used during mounting. Figure 14 shows the displacement of the fastener mounted when a low-viscosity adhesive was used during mounting (the method in Figure 9).

[0042] As shown in Figure 13, in certain tests, the displacement of the fastener increases rapidly in just 10-20 cycles. Using the method in Figure 9, the displacement remains below 0.01 inches even after several hundred cycles.

[0043] This embodiment of the fastener has a pre-formed diameter sufficient to accommodate the diameter of the shank. hole Inserting into concrete material having, and within concrete material hole It is suitable for forming self-threaded grooves.

[0044] Figure 15 shows a comparison of the displacement of fasteners as disclosed in Figures 3 and 4 of Patent Application No. 17 / 246,247, comparing fastener 100 (M3) with a flat top end of the threaded end (M8). This graph shows the displacement of the fasteners during a stepwise crack cycle test, where the mounting is as follows: fastener 100 ("M3 55%") using the method in Figure 2 with a resultant force of 55%, fastener 100 ("M3 w / SLV 55%") using the method in Figure 9 with a resultant force of 55%, fastener 100 ("M3 w / SLV 90%") using the method in Figure 9 with a resultant force of 90%, fastener 100 ("M3 w / SLV 100%") using the method in Figure 9 with a resultant force of 100%, and with a resultant force of 100%, hole This includes fastener 100 ("M3 w / SLV 100% brushless") which uses the method of Figure 9 without brushing, and fastener of application No. 17 / 246,247 ("M8 w / SLV 120% brushless") which has a combined force of 120% and uses the method of Figure 9 without brushing. As shown in Figure 15, hole Without the need for cleaning, the adhesive fastening method disclosed herein offers improved displacement resistance compared to previous fastening methods and substantially improves the performance of numerous types of concrete fasteners.

[0045] All such embodiments of fasteners discussed herein benefit from using the mounting methods described herein.

[0046] While this subject matter has been described using language specific to structural features and / or methodological actions, it should be understood that the subject matter as defined in the attached claims is not necessarily limited to the specific features or actions described above. Rather, the specific features and actions described above are disclosed as exemplary forms of implementing the claims. The items listed below are those that were included in the claims of the patent application at the time of filing. (Item 1) A method for attaching fasteners to a base material, The fastener is, A shank having a first end and a second end that define the length, The head provided at the second end, The shank has a thread, the thread including a front end and a rear end that are adapted to remove a portion of the base material when inserted into the base material, The aforementioned method, The steps include forming a hole having a diameter that is the nominal diameter of the shank of the fastener to be attached to the base material, The steps include filling the hole with an adhesive having a viscosity of 350 cP or less, The steps include rotating the fastener toward the hole so that when the screw thread is fully inserted into the hole, the adhesive is pressed into the shank and the portion of the base material adjacent to the screw thread, Methods that include... (Item 2) The method according to item 1, wherein the filling step includes filling the hole with an adhesive with a pressure of 150 cP or less. (Item 3) The method according to item 1, wherein the rotating step is performed before the gel time of the adhesive has elapsed. (Item 4) The method according to item 1, further comprising the step of cleaning the hole with forced air before the filling step. (Item 5) The method according to item 1, further comprising the step of cleaning the hole with a brush before the filling step. (Item 6) The method according to item 1, further comprising the step of curing the adhesive. (Item 7) The method according to item 1, wherein the base material is concrete. (Item 8) A fastening structure, Substrate and A hole having a diameter that is the nominal diameter of the shank of the fastener to be attached to the base material, A fastener for a hole in the base material, the fastener comprising: a shank having a first end and a second end defining a length; a head provided at the second end and adjacent to the upper surface of the base material; and a thread provided on the shank, the thread including a front end and a rear end adapted to remove a portion of the base material when inserted into the base material, wherein the thread is embedded in the base material along the length of the hole; An adhesive having an attachment viscosity of 350 cP or less, the adhesive being embedded in the wall of the hole and in the substrate adjacent to the threads of the embedded fastener, A fastening structure comprising: (Item 9) The structure according to item 8, wherein the adhesive has an attachment viscosity of 150 cP or less. (Item 10) The structure described in item 8, wherein the base material is concrete.

Claims

1. A method for attaching fasteners to a base material, The fastener is, A shank having a first end and a second end that define the length, The head provided at the second end, The shank has a thread, the thread including a front end and a rear end that are adapted to remove a portion of the base material when inserted into the base material, The aforementioned method, The steps include forming a hole having the same diameter as the nominal diameter of the shank of the fastener to be attached to the base material, The steps include using an injection gun to fill the hole with an adhesive having a viscosity of less than 150 cP, The steps include rotating the fastener toward the hole so that when the screw thread is fully inserted into the hole, the adhesive is pressed into the shank and the portion of the base material adjacent to the screw thread, Methods that include...

2. The method according to claim 1, wherein the rotating step is performed before the gel time of the adhesive has elapsed.

3. The method according to claim 1, further comprising the step of cleaning the hole with forced air before the filling step.

4. The method according to claim 1, further comprising the step of cleaning the hole with a brush before the filling step.

5. The method according to claim 1, further comprising the step of curing the adhesive.

6. The method according to claim 1, wherein the base material is concrete.

7. A method for manufacturing a fastening structure, The fastening structure is Substrate and Equipped with fasteners, The fastener is, A shank having a first end and a second end that define the length, The head provided at the second end, The shank has a thread, the thread including a front end and a rear end that are adapted to remove a portion of the base material when inserted into the base material, The aforementioned manufacturing method is The steps include forming a hole having the same diameter as the nominal diameter of the shank of the fastener to be attached to the base material, The steps include using an injection gun to fill the hole with an adhesive having a viscosity of less than 150 cP, The steps include rotating the fastener toward the hole so that when the screw thread is fully inserted into the hole, the adhesive is pressed into the shank and the portion of the base material adjacent to the screw thread, A manufacturing method that includes this.

8. The manufacturing method according to claim 7, wherein the base material is concrete.

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