A lightweight calcium silicate board assembled ceiling application system
Through the lightweight calcium silicate board prefabricated ceiling application system, the existing ceiling system has been solved, and the problems of poor connection effect and low fixed strength are achieved, fast and stable ceiling installation is achieved, and the A1-level fire resistance is provided.
Patent Information
- Application Number
- CN202421263976.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-06-05
- Publication Date
- 2025-04-11
- Estimated Expiration
- 2034-06-05
AI Technical Summary
The existing ceiling system has poor connection effect, low fixing strength, and difficult materials to meet the A-level fire protection requirements, and is complex and time-consuming.
The lightweight calcium silicate board prefabricated ceiling application system is adopted, including fixed light steel keels, light steel fixing hooks, lightweight calcium silicate board ceiling components and connection adjustment angle codes. These components are used to achieve rapid connection and leveling, avoiding the use of a large number of aluminum connecting keels.
It realizes pure dry assembly without the need for overall putty leveling and grinding, saves labor time and cost, improves overall stability after installation, avoids the risk of violent shaking and falling, and the lightweight calcium silicate ceiling has A1-level fire resistance.
Smart Images

Figure CN222745410U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of indoor assembled decoration ceilings, in particular to an application system of a lightweight calcium silicate board assembled ceiling. Background Art
[0002] With the continuous promotion of the global process of building assembly, from 3D printed concrete to integrated exterior wall insulation decorative panels, from indoor partition wall assembly to interior wall decoration, keel ceiling and floor assembly, the current indoor ceiling construction method mostly uses 9.5mm double-layer paper-faced gypsum board fixed on the light steel keel frame with self-tapping screws, first brush white latex - paste non-woven bandage to deal with the joints - apply putty twice - use sandpaper to polish flat - spray / roll latex paint finish; or use mineral wool board ceiling (specifications: 600mm*600mm / 600mm*1200mm) block ceiling for construction, the mineral wool board ceiling is connected to the horizontal and vertical "T"-shaped aluminum keel through the light steel keel frame, and then the mineral wool board ceiling is overlapped on the "T"-shaped aluminum keel aluminum horizontal and vertical keel.
[0003] The current problems with the ceiling application system are:
[0004] 1. The surface of the paper-faced gypsum board needs to be covered with putty, and the putty layer and the surface of the mineral wool board tend to turn yellow over time, affecting the decorative effect. The other two materials themselves are difficult to meet the requirements of Class A fire protection alone. At the same time, the two materials cannot be milled in the thickness direction or the strength of the milling groove is insufficient, and they cannot be effectively connected with the keel or aluminum keel;
[0005] 2. Existing ceiling systems require a large number of aluminum keels to support the panels. The installation process of aluminum keels is complicated, time-consuming, and costly. In addition, there is no fixing device between the ceiling panel and the supporting aluminum keel, but simply assembled, which poses a high risk of falling when there is severe shaking. Utility Model Content
[0006] The utility model aims to provide a light calcium silicate board assembled ceiling application system in view of the poor connection effect and low fixing strength of the hanging system existing in the prior art.
[0007] The technical solution adopted to achieve the purpose of this utility model is:
[0008] A light calcium silicate board assembled ceiling application system, comprising a fixed light steel keel, a light steel fixing hook, a light calcium silicate board ceiling assembly and a connection adjustment angle code;
[0009] The connection adjustment angle bracket is a metal piece with an "L"-shaped cross section, and one side of the connection adjustment angle bracket is provided with an upper and lower adjustment hole, and the other side is provided with a left and right adjustment hole;
[0010] The light steel fixing hook is a metal piece with an "L"-shaped cross section, including a long side and a short side, and there are reverse fixing piece slots on both sides of the long side of the light steel fixing hook;
[0011] The top of the fixed light steel keel is connected and fixed to the roof floor, the bottom of the fixed light steel keel is connected and fixed to the front and rear adjustment holes of the connection and adjustment angle code, the upper and lower adjustment holes of the connection and adjustment angle code are inserted into the reverse fixing piece slot of the light steel fixing hook for connection and fixation, the short side of the light steel fixing hook fixes the lightweight calcium silicate board ceiling assembly, and the lightweight calcium silicate board ceiling assembly is leveled through the front and rear adjustment holes and the upper and lower adjustment holes of the connection and adjustment angle code, and the lightweight calcium silicate board ceiling assembly is fixed to the fixed keel.
[0012] In the above technical solution, the fixed light steel keel includes a main keel, a secondary keel and a hanger, one end of the hanger is fixedly connected to the roof floor, and the other end is fixedly connected to the top of the main keel, the secondary keel is fixedly connected to the bottom of the main keel by snap-fitting, and the secondary keel and the main keel form a mesh structure.
[0013] In the above technical solution, the thickness of the connecting and adjusting angle code is 0.8-1mm, the two sides of the connecting and adjusting angle code are equal in length, and the length and width are both 45-50mm, the front and rear adjustment holes are strip holes of 20-30mm, and the upper and lower adjustment holes are strip holes of 20-30mm.
[0014] In the above technical solution, the width of the light steel fixing hook is 50-55mm, the length of the long side is 50-55mm, the left and right lengths of the reverse fixing piece slot are 5-10mm respectively, the depth of the reverse fixing piece slot is 1-1.5mm, and a screw fixing hole is provided at two-thirds of the center position of the long side; the short side depth is 20-30mm, the composite thickness (the thickness from the upper surface to the lower surface of the short side) is 1.5-2mm, and the short side is a "Z" shaped symmetrical hook setting.
[0015] In the above technical solution, the lightweight calcium silicate board ceiling assembly includes a lightweight calcium silicate board decorative board, a grooved back strip, a first overlapping back strip, a second overlapping back strip and a balancing reinforcement strip. The grooved back strip, the first overlapping back strip, the second overlapping back strip and the balancing reinforcement strip are fixed on the lightweight calcium silicate ceiling in a "mouth" shape. The "Z"-shaped symmetrical hooks are inserted into the grooved back strip to form a positioning fixation. Multiple lightweight calcium silicate board ceiling assemblies are spliced by the first overlapping back strip and the second overlapping back strip. An "L"-shaped edge strip is provided at the connection between the lightweight calcium silicate board ceiling assembly and the wall.
[0016] In the above technical solution, the grooved back strip, the first overlapping back strip, the second overlapping back strip and the balancing reinforcement strip are all lightweight calcium silicate boards, and the thickness of the grooved back strip, the first overlapping back strip, the second overlapping back strip and the balancing reinforcement strip is consistent with the lightweight calcium silicate board decorative panel.
[0017] In the above technical solution, the lightweight calcium silicate board decorative plate is formed by painting or decorating the surface of the lightweight calcium silicate board, and the four sides of the lightweight calcium silicate board decorative plate are chamfered by 1-3 mm.
[0018] In the above technical solution, the density of the lightweight calcium silicate board is 0.8±0.05g / cm 3 , A1 fireproof, with nailability and milling edge and hole milling properties.
[0019] In the above technical solution, the grooved back strip, the first overlapping back strip, the second overlapping back strip and the balancing reinforcement strip have the same width of 80-100 mm, the grooved back strip and the first overlapping back strip are of the same length as the lightweight calcium silicate board decorative panel, the second overlapping back strip is of the same length as the balancing reinforcement strip, and the width of the lightweight calcium silicate board decorative panel is equal to the length of the second overlapping back strip plus the width of the first overlapping back strip and the grooved back strip.
[0020] In the above technical solution, the groove depth of the grooved back strip is 20-30mm, and the groove height is 2-2.5mm. The grooved back strip, the first overlapping back strip, and the second overlapping back strip form a "mouth" shaped combination. After the groove of the "mouth" shaped combination is placed downward and overlapped with the back of the lightweight calcium silicate board decorative board on all sides, it is firmly bonded by 20-30mm translation along the diagonal direction of the "mouth" from any end of the placement of the grooved back strip.
[0021] Compared with the prior art, the beneficial effects of the utility model are:
[0022] 1. The lightweight calcium silicate board assembled ceiling application system of the utility model does not require overall putty leveling and grinding, has little pollution during on-site construction, and realizes pure dry assembly; on the other hand, the ceiling application system avoids the use of a large number of aluminum connecting keels, and uses light steel fixing hooks and connecting adjustment angles to achieve connection and fixation, saving labor time and cost; finally, the lightweight calcium silicate board ceiling is connected to the fixed keel through a grooved back strip, and the ceilings are overlapped by the back strips to achieve rapid assembly, improve the overall stability after installation, and avoid the risk of falling due to severe shaking.
[0023] 2. The light calcium silicate board ceiling in the utility model has A1 grade non-combustibility, and the surface can be treated and decorated by painting. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] Figure 1 This is the cross-section node diagram of the lightweight calcium silicate board prefabricated ceiling application system;
[0025] Figure 2 Axonometric drawing for fixing light steel keel;
[0026] Figure 3 Axonometric drawing of a lightweight calcium silicate board ceiling assembly;
[0027] Figure 4 Axonometric drawing for adjusting the angle code;
[0028] Figure 5 This is the axonometric view of the light steel hook.
[0029] In the figure: 1-fixed keel, 2-light calcium silicate board ceiling assembly, 3-connection adjustment angle bracket, 4-light steel fixing hook, 5-self-tapping cross screw, 6-flat head cross screw, 7-"L" type edge strip;
[0030] 1-1- suspension rod, 1-2- main keel, 1-3- secondary keel, 1-4- inverted T-shaped connection;
[0031] 2-1-light calcium silicate decorative board, 2-2-grooved back strip, 2-3-first lap back strip, 2-4-second lap back strip, 2-5-balance reinforcement strip;
[0032] 3-1-front and rear adjustment holes, 3-2-up and down adjustment holes;
[0033] 4-1-“Z” shaped symmetrical hooks, 4-2-screw fixing holes, 4-3-fixing piece slots. DETAILED DESCRIPTION
[0034] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.
[0035] Example 1
[0036] A lightweight calcium silicate board assembled ceiling application system, such as Figure 1 As shown, it includes a fixed light steel keel, a light steel fixing hook 4, a light calcium silicate board ceiling assembly 2 and a connection adjustment angle code 3;
[0037] like Figure 2 As shown, the fixed light steel keel is equipped with a main keel 1-2, a secondary keel 1-3 and a suspension rod 1-1. One end of the suspension rod 1-1 is fixedly connected to the roof floor, and the other end is fixedly connected to the top of the main keel 1-2. The secondary keel 1-3 is fixedly connected to the bottom of the main keel 1-2 by snap-fitting. The secondary keel 1-3 and the main keel 1-2 form a mesh structure. In this embodiment, the bottom of the main keel 1-2 is evenly provided with an inverted T-shaped connecting part 1-4, and the secondary keel 1-3 is "C" shaped, and the two are fixed together.
[0038] like Figure 4 As shown, the connection adjustment angle code 3 is a metal piece of equal length and "L"-shaped cross section, with a thickness of 0.8-1mm, a length and a width of 45-50mm, and one side of the connection adjustment angle code 3 is provided with an up-and-down adjustment hole 3-2, and the front-and-back adjustment hole 3-1 is a strip hole of 20-30mm, and the other side is provided with a left-and-right adjustment hole, and the up-and-down adjustment hole 3-2 is a strip hole of 20-30mm. The connection adjustment angle code 3 of the utility model can not only realize the flexible leveling of the horizontal surface of the light calcium silicate board ceiling, but also realize the front-and-back position adjustment with the fixed keel 1, avoiding the problem of repeated nailing of the secondary keel 1-3 for front-and-back position adjustment, and greatly improving the success rate of one-time installation.
[0039] like Figure 5 As shown, the light steel fixing hook 4 is a metal part with an "L"-shaped cross-section and a width of 50-55mm, including a long side and a short side, and the long side is 50-55mm long. There are reverse fixing slots 4-3 on both sides of the long side of the light steel fixing hook 4, and there are reverse fixing slots 4-3 on both sides of the long side, with a left and right length of 5-10mm and a depth of 1-1.5mm. A screw fixing hole 4-2 is provided at two-thirds of the center position of the long side, and the short side is a "Z"-shaped symmetrical hook 4-1 with a depth of 20-30mm and a composite thickness of 1.5-2mm. The setting of the "Z"-shaped symmetrical hook 4-1 in the light steel fixing hook 4 of the utility model can save material costs while achieving precise coupling with the grooved back strip 2-2 located on the back of the light calcium silicate board ceiling component 2, thereby improving the stability of the overall light calcium silicate board ceiling; the setting of the screw fixing hole 4-2 avoids the problems of poor alignment of the fixing screw position and complex fixing by workers during construction, thereby further reducing construction costs; the setting of the fixing part slot 4-3 allows the upper and lower adjustment holes 3-2 ends of the connection adjustment angle code 3 to be quickly inserted into the light steel fixing hook 4, thereby achieving position alignment and fixation, and avoiding left and right relative displacement after alignment, thereby increasing stability and anti-deformation ability.
[0040] like Figure 3As shown, the lightweight calcium silicate board ceiling assembly 2 includes a lightweight calcium silicate board decorative board 2-1, a grooved back strip 2-2, a first overlapping back strip 2-3, a second overlapping back strip 2-4 and a balancing reinforcement strip 2-5. The grooved back strip 2-2, the first overlapping back strip 2-3, the second overlapping back strip 2-4 and the balancing reinforcement strip 2-5 are fixed on the lightweight calcium silicate ceiling in a "mouth" shape to increase the structural stability of the lightweight calcium silicate board ceiling assembly 2. The grooved back strip 2-2, the first overlapping back strip 2-3, the second overlapping back strip and the balancing reinforcement strip 2-5 are all lightweight calcium silicate boards. The thickness of the grooved back strip 2-2, the first overlapping back strip 2-3, the second overlapping back strip and the balancing reinforcement strip 2-5 is consistent with that of the lightweight calcium silicate board decorative board 2-1. The lightweight calcium silicate board ceiling assembly 2 is directly in contact with the wall or connected to the wall through an "L"-shaped edge strip 7.
[0041] The top of the fixed light steel keel is connected and fixed to the roof floor, the bottom of the fixed light steel keel is connected and fixed to the front and rear adjustment holes 3-1 of the connection adjustment angle code 3 by a self-tapping cross screw 5, the upper and lower adjustment holes 3-2 of the connection adjustment angle code 3 are inserted into the reverse fixing piece slot 4-3 of the light steel fixed hook 4 and connected and fixed to the screw fixing hole 4-2 by a flat head cross screw 6, the "Z" shaped symmetrical hook 4-1 is inserted into the grooved back strip 2-2 to form a positioning fixation, and a plurality of the light calcium silicate The board ceiling components 2 are spliced by the first overlapping back strips 2-3 and the second overlapping back strips 2-4, and the light calcium silicate board ceiling components 2 are leveled by the front and rear adjustment holes 3-1 and the upper and lower adjustment holes 3-2 of the connection adjustment angle code 3. The light calcium silicate board ceiling components 2 are fixed to the fixed keel 1, and the light calcium silicate board ceiling components 2 can be cut close to the wall according to actual conditions. The "L"-shaped edge strip 7 / wall panel 7 is fixed to the wall and then connected to the support to complete the assembly installation.
[0042] Example 2
[0043] Based on Example 1, this example provides a light calcium silicate board assembled ceiling application system. The light calcium silicate board decorative board 2-1 in this example is formed by coating or decorating the surface of the light calcium silicate board. The four sides of the light calcium silicate board decorative board 2-1 are chamfered by 1-3 mm. The density of the light calcium silicate board is 0.8±0.05 g / cm 3, A1 fireproof, good nailability and milling performance. The grooved back strip 2-2, the first lap back strip 2-3, the second lap back strip 2-4 and the balance reinforcement strip 2-5 have the same width of 80-100mm, the grooved back strip 2-2 and the first lap back strip 2-3 are the same length as the light calcium silicate board decorative board 2-1, the second lap back strip 2-4 is the same length as the balance reinforcement strip 2-5, and the width of the light calcium silicate board decorative board 2-1 is equal to the length of the second lap back strip plus the width of the first lap back strip and the grooved back strip 2-2.
[0044] The grooved back strip 2-2 has a groove depth of 20-30mm and a groove height of 2-2.5mm. The grooved back strip 2-2, the first overlapping back strip 2-3, and the second overlapping back strip 2-4 form a "mouth" shaped combination. The "mouth" shaped combination, on the one hand, realizes that the lightweight calcium silicate board ceiling assembly 2 can be connected and fixed to the fixed keel 1 through the light steel fixing hook 4, and on the other hand, realizes the assembled installation between the lightweight calcium silicate board ceiling assemblies 2 through the first overlapping back strip 2-3 and the second overlapping back strip 2-4. The installation is simple and efficient, without dust pollution, and the overall stability after installation is high, avoiding the risk of severe shaking and falling. Furthermore, after the groove of the "mouth" shaped combination is placed downward and overlapped with the back of the lightweight calcium silicate board decorative panel 2-1, it is firmly bonded by 20-30mm translation along the diagonal direction of the "mouth" shape from any end of the placement of the grooved back strip 2-2.
[0045] In this embodiment, the lightweight calcium silicate board ceiling assembly 2 is prepared according to the following steps:
[0046] 1. Use 8mm light calcium silicate board and table saw to process it into 300*600mm block-shaped light calcium silicate board ceiling, and chamfer the board around or make other shapes for later use;
[0047] 2. Use 8mm light calcium silicate board and use table saw and other processing tools to make slats. The width of the slats is 80mm. The length of the grooved back strip 2-2 and the first overlapping back strip 2-3 is 600mm. The length of the second overlapping back strip 2-4 and the balance reinforcement strip 2-5 is 140mm. The grooved back strip 2-2 is grooved with a depth of 20-30mm and a groove height of 2-3mm. All back strips are ready for use.
[0048] 3. Assemble a grooved back strip 2-2, two overlapping back strips and a balance reinforcement strip 2-5 in a "mouth" shape on the back of the lightweight calcium silicate board decorative board 2-1, and bond and dry them at the joints with silane polyether glue or silicone glue;
[0049] 4. Place the "mouth"-shaped combined groove with the opening facing downwards and coincide it with the four-week back of the lightweight calcium silicate board decorative panel 2-1. Then, translate it 25 mm along the diagonal direction of the "mouth"-shaped from any one end of the placement position of the grooved back strip 2-2 and bond it firmly through silane polyether glue or silicone glue to complete the production of the lightweight calcium silicate board ceiling assembly 2.
[0050] For ease of explanation, spatial relative terms such as "upper", "lower", "left", and "right" are used in the embodiments to describe the relationship of one element or feature shown in the figure relative to another element or feature. It should be understood that, in addition to the orientation shown in the figure, the spatial terms are intended to include different orientations during the use or operation of the device. For example, if the device in the figure is inverted, the element described as being "below" other elements or features will be positioned "above" other elements or features. Therefore, the exemplary term "lower" can include both the upper and lower orientations. The device can be positioned in other ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein can be interpreted accordingly.
[0051] Moreover, relative relationship terms such as "first" and "second" are only used to distinguish one component with the same name from another, and do not necessarily require or imply any such actual relationship or order between these components.
[0052] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art of this technology, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.
Claims
1. A lightweight calcium silicate board assembled ceiling application system, characterized in that: Including fixed light steel keel, light steel fixing hook, light calcium silicate board ceiling assembly and connection adjustment angle code; The connection adjustment angle bracket is a metal piece with an "L"-shaped cross section, and one side of the connection adjustment angle bracket is provided with an upper and lower adjustment hole, and the other side is provided with a left and right adjustment hole; The light steel fixing hook is a metal piece with an "L"-shaped cross section, including a long side and a short side, and there are reverse fixing piece slots on both sides of the long side of the light steel fixing hook; The top of the fixed light steel keel is connected and fixed to the roof floor, the bottom of the fixed light steel keel is connected and fixed to the front and rear adjustment holes of the connection and adjustment angle code, the upper and lower adjustment holes of the connection and adjustment angle code are inserted into the reverse fixing piece slot of the light steel fixing hook for connection and fixation, the short side of the light steel fixing hook fixes the lightweight calcium silicate board ceiling assembly, and the lightweight calcium silicate board ceiling assembly is leveled through the front and rear adjustment holes and the upper and lower adjustment holes of the connection and adjustment angle code, and the lightweight calcium silicate board ceiling assembly is fixed to the fixed keel.
2. The lightweight calcium silicate board assembled ceiling application system according to claim 1, characterized in that: The fixed light steel keel includes a main keel, a secondary keel and a hanger, one end of the hanger is fixedly connected to the roof floor, and the other end is fixedly connected to the top of the main keel. The secondary keel is fixedly connected with the bottom of the main keel by snap-fitting, and the secondary keel and the main keel form a mesh structure.
3. The lightweight calcium silicate board assembled ceiling application system according to claim 1, characterized in that: The thickness of the connecting and adjusting angle code is 0.8-1mm, the two sides of the connecting and adjusting angle code are equal in length, and the length and width are both 45-50mm, the front and rear adjusting holes are strip holes of 20-30mm, and the upper and lower adjusting holes are strip holes of 20-30mm.
4. The lightweight calcium silicate board assembled ceiling application system according to claim 1 is characterized in that: The width of the light steel fixing hook is 50-55mm, the length of the long side is 50-55mm, the left and right lengths of the reverse fixing piece slot are 5-10mm respectively, the depth of the reverse fixing piece slot is 1-1.5mm, and a screw fixing hole is provided at two-thirds of the center position of the long side; the short side depth is 20-30mm, the composite thickness is 1.5-2mm, and the short side is a "Z" shaped symmetrical hook setting.
5. The lightweight calcium silicate board assembled ceiling application system according to claim 4 is characterized in that: The lightweight calcium silicate board ceiling assembly includes a lightweight calcium silicate board decorative board, a grooved back strip, a first overlapping back strip, a second overlapping back strip and a balancing reinforcement strip. The grooved back strip, the first overlapping back strip, the second overlapping back strip and the balancing reinforcement strip are fixed on the lightweight calcium silicate ceiling in a "mouth" shape. The "Z"-shaped symmetrical hooks are inserted into the grooved back strip to form a positioning fixation. Multiple lightweight calcium silicate board ceiling assemblies are spliced by the first overlapping back strip and the second overlapping back strip. An "L"-shaped edge strip is provided at the connection between the lightweight calcium silicate board ceiling assembly and the wall.
6. The lightweight calcium silicate board assembled ceiling application system according to claim 5 is characterized in that: The grooved back strip, the first overlapping back strip, the second overlapping back strip and the balance reinforcement strip are all lightweight calcium silicate boards, and the thickness of the grooved back strip, the first overlapping back strip, the second overlapping back strip and the balance reinforcement strip is consistent with the lightweight calcium silicate board decorative panel.
7. A lightweight calcium silicate board assembled ceiling application system according to claim 6, characterized in that: The light calcium silicate board decorative board is formed by painting or decorating the surface of the light calcium silicate board, and the four sides of the light calcium silicate board decorative board are chamfered by 1-3 mm.
8. The lightweight calcium silicate board assembled ceiling application system according to claim 7 is characterized in that: The density of the light calcium silicate board is 0.8±0.05 g / cm 3 , A1 fireproof, with nailability and milling edge and hole milling properties.
9. A lightweight calcium silicate board assembled ceiling application system according to claim 8, characterized in that: The grooved back strip, the first overlapping back strip, the second overlapping back strip and the balancing reinforcement strip have the same width of 80-100mm. The grooved back strip and the first overlapping back strip are of the same length as the lightweight calcium silicate board decorative panel, the second overlapping back strip is of the same length as the balancing reinforcement strip, and the width of the lightweight calcium silicate board decorative panel is equal to the length of the second overlapping back strip plus the width of the first overlapping back strip and the grooved back strip.
10. A lightweight calcium silicate board assembled ceiling application system according to claim 9, characterized in that: The groove depth of the grooved back strip is 20-30mm, and the groove height is 2-2.5mm. The grooved back strip, the first overlapping back strip, and the second overlapping back strip form a "mouth" shaped combination. After the groove of the "mouth" shaped combination is placed downward and overlapped on all sides of the back of the lightweight calcium silicate board decorative board, it is firmly bonded by 20-30mm translation along the diagonal direction of the "mouth" from any end of the placement of the grooved back strip.