An easy-to-assemble waterproof modular house floor structure and its application method

CN116122534BActive Publication Date: 2026-09-01中铁城建集团第三工程有限公司 +1
View PDF 4 Cites 0 Cited by

Patent Information

Application Number
CN202211538632.4
Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
Filing Date
2022-12-02
Publication Date
2026-09-01
Estimated Expiration
2042-12-02

AI Technical Summary

Technical Problem

[0003]现有的拼接地板,需在干透的混凝土地面上进行逐个的拼接时,主要通过地板的形变实现拼接,拼接后使用时,倒在上面的水流,容易经地板之间缝隙流至干透的混凝土上,造成屋内潮湿,防水性能较差,且在拼接时,需用力卡接,使用较为不便

Benefits of technology

[0019]与现有技术相比,本发明的有益效果是:本易拼接的防水组合式房屋地板结构及其使用方法,具有以下好处:

✦ Generated by Eureka AI based on patent content.

Smart Images

  • Figure CN116122534B_ABST
    Figure CN116122534B_ABST
Patent Text Reader

Abstract

This invention discloses an easy-to-assemble waterproof modular house floor structure and its usage method, including a floor body, splicing units, and edge sealing units. The floor body has a circular groove at its lower end. The splicing unit includes a board groove, a connecting plate, a cylindrical groove, a rubber cylinder, a ventilation channel, and a column groove. Board grooves are formed around the lower end of the floor body. One end of the connecting plate is engaged in the board groove, and locking strips are installed on the upper sides of both ends of the connecting plate, engaging in the locking slots within the board grooves. Frame-shaped cylindrical grooves are formed around the center of the floor body, and frame-shaped rubber cylinders are installed within these grooves. This easy-to-assemble waterproof modular house floor structure and its usage method allow for splicing with wet concrete without excessive force. The floor joints utilize both air inflation and rubber strip engagement methods, achieving double waterproofing, resulting in stronger waterproofing performance, preventing indoor dampness, and making it more convenient to use.
Need to check novelty before this filing date? Find Prior Art

Description

Technical Field

[0001] This invention relates to the field of easily assembled waterproof modular house flooring technology, specifically to an easily assembled waterproof modular house flooring structure and its usage method. Background Technology

[0002] Interlocking flooring is made by piecing together small pieces of flooring material. It's a relatively new type of flooring product, primarily made of polypropylene. Interlocking flooring is very popular in modern home decoration.

[0003] Existing interlocking flooring requires individual splicing on a completely dry concrete surface. This splicing is mainly achieved through the deformation of the floorboards. When used after splicing, water spilled on the floorboards can easily flow through the gaps between the floorboards onto the dried concrete, causing dampness indoors. It also has poor waterproofing performance. Furthermore, it requires force to snap the boards together during splicing, making it inconvenient to use. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the existing defects and provide an easy-to-assemble waterproof modular house floor structure and its usage method. When assembling, it can be combined with the laid wet concrete without much force to complete the assembly. The floor joints adopt two methods: air inflation and adhesive strip snap-fit, to achieve double waterproofing, which enhances the waterproof performance, prevents the house from becoming damp, and makes it more convenient to use. It can effectively solve the problems in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: an easy-to-assemble waterproof modular house floor structure and its usage method, comprising a floor body, splicing units, and edge sealing units;

[0006] Floor body: A circular groove is provided at the bottom;

[0007] The splicing unit includes a board groove, a connecting plate, a cylindrical groove, a rubber cylinder, ventilation channels, and a column groove. The lower end of the flooring body has board grooves around its four sides. One end of the connecting plate is engaged in the board groove. Each end of the connecting plate has a locking strip on its upper side, which engages in a slot within the board groove. A frame-shaped cylindrical groove is located in the center of the flooring body, and a frame-shaped rubber cylinder is installed within it. Four ventilation channels are located inside the flooring body, with their outer ends connected to the rubber cylinders. A column groove is located in the center of the upper end of the flooring body, and the inner ends of the four ventilation channels are connected to the lower end of the column groove. The introduced air is evenly delivered to the frame-shaped rubber cylinders through the four ventilation channels. After initial splicing, the rubber cylinders are opened and tightly fitted to the rubber cylinders of another flooring unit. This improves the tightness of the connection and prevents water seepage, enhancing waterproofing and preventing dampness indoors.

[0008] Edge banding unit: Installed on the upper perimeter of the floor body.

[0009] Furthermore, the splicing unit also includes a rubber column. An arc-shaped retaining ring is installed within the column groove. The rubber column is installed in the column groove and engaged with the arc-shaped retaining ring. A vertically penetrating air hole is opened in the middle of the rubber column. The rubber column is glued to the column groove. An external air pump is inserted into the air hole in the middle of the rubber column, and air is pumped in. This allows gas to be delivered into the rubber cylinder through four air channels. After the gas delivery is complete, the air pump is pulled out. During the pulling process, the rubber cylinder deforms, sealing the air hole and further preventing internal gas from escaping and external water from entering the floor, thus improving waterproofing.

[0010] Furthermore, the edge sealing unit includes edge strips and arc grooves. Edge strips are installed on the upper sides of all four sides of the floor body, and arc grooves are formed on the upper sides of all four sides of the floor body, with the arc grooves located above the edge strips. After splicing, the edge strips and arc grooves facilitate the insertion of I-shaped inserts, increasing the tightness of the upper connection between the two baseboards.

[0011] Furthermore, the edge sealing unit also includes an I-shaped insert and an arc strip. The lower right side of the I-shaped insert is engaged with the edge strip, and both ends of the I-shaped insert have arc strips. The right arc strip engages with the arc groove on the left side of the flooring body. The I-shaped insert is made of rubber. After splicing, the lower left and right sides of the I-shaped insert are engaged with the edge strips of the two flooring units at their closest ends. During engagement, the arc strips on the left and right sides of the edge strip can engage with the arc grooves of the two flooring units at their closest ends. Then, applying sealant to the gap between the upper sides of the left and right ends of the I-shaped insert and the two flooring units achieves initial waterproofing.

[0012] Furthermore, it also includes a patterned layer and a resin layer. The patterned layer is installed on the upper end of the flooring body, and the resin layer is installed on the upper end of the patterned layer. Different patterns are drawn in the patterned layer, which enhances the style of the flooring. After splicing and inflation, the upper surface of the resin layer is sanded and polished to improve the gloss of the upper surface of the flooring. The resin layer is made of resin mixture and solidification with a suitable hardness.

[0013] Furthermore, it also includes insert blocks, with insert blocks installed at the lower ends of both the floorboard body and the connecting plate. After laying a thin layer of wet concrete indoors, one end of the connecting plate is snapped into the underside of another floorboard and installed on the concrete floor. Then, one side of the lower edge of this floorboard is snapped into the other end of the connecting plate. During snapping, the locking strip on the connecting plate engages with the locking groove provided in the board groove, so that the two floorboards are tightly connected. When installed on concrete, the circular lower groove and the insert blocks at the lower ends of the floorboard body and the connecting plate can increase the contact area with the concrete, increase adhesion, and achieve rapid splicing and installation without much force.

[0014] A method for using an easy-to-assemble waterproof modular house floor structure includes the following steps:

[0015] S1. First, snap one end of the connecting plate to the underside of another floorboard and install it on the concrete ground. When installing this floorboard, snap one side of the bottom edge of this floorboard to the other end of the connecting plate. When snapping, the snap strip on the connecting plate snaps into the snap groove provided in the board groove, so that the two floorboards are tightly connected. When installing on the concrete, the circular bottom groove, the floorboard body and the insert at the bottom of the connecting plate can increase the contact area with the concrete, increase the adhesion, and achieve the initial splicing installation.

[0016] S2. After the entire floorboard is assembled, take out the rubber I-shaped insert and attach the left and right sides of the lower end of the I-shaped insert to the edge strips of the two floorboards that are close to each other. When attaching, the left and right arc strips of the edge strips can be inserted into the arc grooves of the two floorboards that are close to each other. Then, apply sealant to the gap between the upper side of the left and right ends of the I-shaped insert and the two floorboards to achieve initial waterproofing.

[0017] S3. Next, use an external basketball to insert the air needle into the air hole in the middle of the rubber column, and use an external air pump to inflate it. The gas can be delivered into the rubber cylinder through the four air channels, causing the rubber cylinder to open. When opened, it can fit tightly with the rubber cylinder of another floor that is also open. This improves the tightness of the connection and prevents water from seeping down and affecting the building.

[0018] S4. Finally, sand and polish the top surface of the resin layer to improve the gloss of the upper surface of the floor. The resin layer is made of resin mixture and solidification with suitable hardness. Different patterns are drawn in the pattern layer, which improves the style of the floor and can better meet the needs of customers.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows: This easily assembled waterproof modular house floor structure and its method of use have the following advantages:

[0020] 1. This easy-to-assemble waterproof modular house floor structure is equipped with splicing units. The gas introduced can be evenly delivered to the frame-shaped rubber tube through four ventilation channels. After the initial splicing is completed, the rubber tube is opened and tightly fitted with the rubber tube of another floor. This improves the tightness of the connection and prevents water seepage, thus improving waterproof performance and making the house less prone to dampness.

[0021] 2. The easy-to-assemble waterproof modular house floor structure has splicing units. An external air-inflating needle is inserted into the air hole in the middle of the rubber column. The external air-inflating device inflates the rubber cylinder, allowing the gas to be delivered into the rubber cylinder through four air channels. After the gas delivery is complete, the air-inflating needle is pulled out. During the pulling process, the rubber cylinder deforms, which can seal the air hole, further preventing internal gas from escaping and external water from entering the floor, thus improving waterproofness.

[0022] 3. This easy-to-assemble waterproof modular house floor structure is equipped with an edge sealing unit. The I-shaped insert is made of rubber. After the assembly is completed, the left and right sides of the lower end of the I-shaped insert are respectively snapped onto the edge strips of the two floorboards that are close to each other. When snapping, the arc strips on the left and right sides of the edge strip can be snapped into the arc grooves of the two floorboards that are close to each other. Then, apply sealant to the gap between the upper side of the left and right ends of the I-shaped insert and the two floorboards to achieve initial waterproofing.

[0023] 4. This easy-to-assemble waterproof modular house floor structure involves laying a thin layer of wet concrete indoors, then interlocking one end of the connecting board with the underside of another floorboard and installing it on the concrete floor. Next, one side of the underside of this floorboard is interlocked with the other end of the connecting board. During interlocking, the locking strip on the connecting board engages with the locking groove provided in the board groove, ensuring a tight connection between the two floorboards. When installed on the concrete, the circular underside groove, the floorboard body, and the insert at the bottom of the connecting board increase the contact area with the concrete, increasing adhesion and enabling rapid splicing and installation without requiring excessive force. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of the present invention;

[0025] Figure 2 This is a schematic diagram of the front cross-sectional structure of the present invention;

[0026] Figure 3 For the present invention Figure 2 A magnified schematic diagram of the partial structure at point A in the middle;

[0027] Figure 4 For the present invention Figure 2 A magnified schematic diagram of the structure at point B in the middle.

[0028] In the diagram: 1 Floor body, 2 Lower groove, 3 Splicing unit, 31 Board groove, 32 Connecting board, 33 Tube groove, 34 Rubber tube, 35 Ventilation duct, 36 Column groove, 37 Rubber column, 4 Edge sealing unit, 41 Edge strip, 42 Arc groove, 43 I-shaped insert, 44 Arc strip, 5 Pattern layer, 6 Resin layer, 7 Insert block. Detailed Implementation

[0029] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] Please see Figures 1-4 The present invention provides a technical solution:

[0031] Example 1: An easy-to-assemble waterproof modular house floor structure and its usage method, including floor body 1, splicing unit 3 and edge sealing unit 4;

[0032] Floor body 1: A circular groove 2 is provided at the bottom;

[0033] Splicing Unit 3: Includes a board groove 31, a connecting plate 32, a cylindrical groove 33, a rubber cylinder 34, a ventilation channel 35, and a column groove 36. Board grooves 31 are formed around the lower perimeter of the floor body 1. One end of the connecting plate 32 is engaged within the board groove 31. Locking strips are installed on the upper sides of both ends of the connecting plate 32, engaging with the locking slots within the board grooves 31. Frame-shaped cylindrical grooves 33 are formed in the center of the floor body 1. Frame-shaped rubber cylinders 34 are installed within the frame-shaped cylindrical grooves 33. Four ventilation channels 35 are formed inside the floor body 1. 5. The outer ends of the four ventilation channels 35 are all connected to the rubber cylinders 34. A column groove 36 is provided in the middle of the upper end of the floor body 1. The inner ends of the four ventilation channels 35 are all connected to the lower end of the column groove 36. The gas introduced can be evenly delivered to the frame-shaped rubber cylinders 34 through the four ventilation channels 35. After the initial splicing is completed, the rubber cylinders 34 are opened and tightly fitted with the rubber cylinders 34 of another floor. On the one hand, this improves the tightness of the connection, and on the other hand, it can prevent water from seeping down, improve the waterproof performance, and make the room less prone to dampness.

[0034] The splicing unit 3 also includes a rubber column 37. An arc-shaped retaining ring is installed in the column groove 36. The rubber column 37 is installed in the column groove 36 and engaged with the arc-shaped retaining ring. A vertically penetrating air hole is opened in the middle of the rubber column 37. The rubber column 37 is glued to the column groove 36. An external basketball pump needle is inserted into the air hole in the middle of the rubber column 37. When the external pump is pumped, the gas is delivered into the rubber cylinder 34 through four air channels 35. After the gas delivery is completed, the pump needle is pulled out. During the pulling process, the rubber cylinder 34 deforms, which seals the air hole, further preventing internal gas from escaping and external water from entering the floor, thus improving waterproofing.

[0035] Example 2:

[0036] The difference between this embodiment and Embodiment 1 is that:

[0037] In this embodiment, an edge sealing unit 4 is also included: installed on the upper sides of the floor body 1.

[0038] The edge sealing unit 4 includes an edge strip 41 and an arc groove 42. The edge strip 41 is installed on the upper sides of all four sides of the floor body 1, and the arc groove 42 is opened on the upper sides of all four sides of the floor body 1. The arc groove 42 is located on the upper side of the edge strip 41. After splicing, the edge strip 41 and the arc groove 42 are used to easily insert the I-shaped insert 43, increasing the tightness of the upper connection between the two base plates.

[0039] The edge sealing unit 4 also includes an I-shaped insert 43 and an arc strip 44. The lower right side of the I-shaped insert 43 is snapped onto the edge strip 41. Both ends of the I-shaped insert 43 are provided with arc strips 44. The right arc strip 44 is snapped into the arc groove 42 on the left side of the floor body 1. The I-shaped insert 43 is made of rubber. After splicing, the lower left and right sides of the I-shaped insert 43 are snapped onto the edge strips 41 of the two floorboards at the same end. When snapping, the arc strips 44 on the left and right sides of the edge strip 41 can be snapped into the arc grooves 42 of the two floorboards at the same end. Then, apply sealant to the gap between the upper sides of the left and right ends of the I-shaped insert 43 and the two floorboards to achieve initial waterproofing.

[0040] It also includes a patterned layer 5 and a resin layer 6. The patterned layer 5 is installed on the upper end of the floor body 1, and the resin layer 6 is installed on the upper end of the patterned layer 5. Different patterns are drawn in the patterned layer 5, which enhances the style of the floor. After the floor is assembled and inflated, the upper surface of the resin layer 6 is sanded and polished to improve the gloss of the upper surface of the floor. The resin layer 6 is made of resin mixture and solidification with appropriate hardness.

[0041] It also includes insert blocks 7, which are installed at the lower end of the floor body 1 and the lower end of the connecting plate 32. After laying a thin layer of wet concrete indoors, one end of the connecting plate 32 is snapped into the underside of another floor and installed on the concrete floor. Then, one side of the lower end of this floor is snapped into the other end of the connecting plate 32. During snapping, the locking strip on the connecting plate 32 is snapped into the locking groove provided in the plate groove 31, so that the two floor pieces are tightly connected. When installed on the concrete, the circular lower groove 2 and the insert blocks 7 at the lower ends of the floor body 1 and the connecting plate 32 can increase the contact area with the concrete, increase the adhesion, and achieve rapid splicing and installation without too much force.

[0042] Example 3:

[0043] The difference between this embodiment and Embodiment 1 is that:

[0044] In this embodiment, a method for using an easily assembled waterproof modular house floor structure includes the following steps:

[0045] S1. First, snap one end of the connecting plate 32 to the underside of another floor and install it on the concrete ground. When installing this floor, snap one side of the bottom edge of this floor to the other end of the connecting plate 32. When snapping, the snap strip on the connecting plate 32 snaps into the snap groove provided in the plate groove 31, so that the two floor pieces are tightly connected. When installed on the concrete, the circular lower groove 2, the floor body 1, and the insert 7 at the bottom of the connecting plate 32 can increase the contact area with the concrete, increase the adhesion, and achieve the initial splicing installation.

[0046] S2. After the entire floorboard is assembled, take out the rubber I-shaped insert 43 and attach the left and right sides of the lower end of the I-shaped insert 43 to the edge strips 41 of the two floorboards that are close to each other. When attaching, the arc strips 44 on the left and right sides of the edge strip 41 can be attached into the arc grooves 42 of the two floorboards that are close to each other. Then, apply sealant to the gap between the upper side of the left and right ends of the I-shaped insert 43 and the two floorboards to achieve initial waterproofing.

[0047] S3. Next, use an external basketball to inflate the air hole in the middle of the rubber column 37. Use an external air pump to inflate the air. The air can be delivered into the rubber cylinder 34 through the four air channels 35, so that the rubber cylinder 34 can be opened. When opened, it can fit tightly with the rubber cylinder 34 of another floor that is opened. On the one hand, it can improve the tightness of the connection, and on the other hand, it can prevent water from seeping down and affecting the building.

[0048] S4. Finally, sand and polish the upper surface of resin layer 6 to improve the gloss of the upper surface of the floor. Resin layer 6 is made of resin mixture and solidification with suitable hardness. Different patterns are drawn in the pattern layer 5, which improves the style of the floor and better meets the needs of customers.

[0049] In use: First, snap one end of the connecting plate 32 to the underside of another floorboard and install it on the concrete ground. When installing this floorboard, snap one side of the bottom edge of this floorboard to the other end of the connecting plate 32. During snapping, the locking strip on the connecting plate 32 snaps into the locking groove provided in the plate groove 31, so that the two floorboards are tightly connected. When installing on the concrete, the circular lower groove 2, the floorboard body 1, and the insert 7 at the bottom of the connecting plate 32 can increase the contact area with the concrete. After the entire floorboard is spliced, take out the rubber I-shaped insert 43 and snap the left and right sides of the lower end of the I-shaped insert 43 onto the edge strip 41 of the two floorboards that are close to each other. During snapping... The curved strips 44 on the left and right sides of the edge strip 41 can be inserted into the curved grooves 42 at the adjacent ends of the two floorboards. Then, apply sealant to the gap between the upper sides of the left and right ends of the I-shaped insert strip 43 and the two floorboards to achieve initial waterproofing. Next, use an external basketball pump needle to insert into the air hole in the middle of the rubber column 37 and use an external pump to inflate it. The gas can be delivered into the rubber cylinder 34 through the four air channels 35, causing the rubber cylinder 34 to open. When opened, it can fit tightly with the rubber cylinder 34 of the other floorboard, which improves the tightness of the connection and prevents water from seeping down. Finally, grind and polish the upper surface of the resin layer 6 to improve the gloss of the upper surface of the floorboard.

[0050] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An easily assembled waterproof modular house floor structure, characterized in that: It includes the floor body (1), splicing unit (3) and edge banding unit (4); Floor body (1): A circular groove (2) is provided at the bottom; The splicing unit (3) includes a board groove (31), a connecting plate (32), a cylinder groove (33), a rubber cylinder (34), a ventilation duct (35), and a column groove (36). The floor body (1) has board grooves (31) on all four sides at the bottom. One end of the connecting plate (32) is inserted into the board groove (31). The upper sides of both ends of the connecting plate (32) are equipped with locking strips, which are inserted into the locking slots provided in the board groove (31). The frame-shaped cylinder... The groove (33) is opened in the middle of the perimeter of the floor body (1). A frame-shaped rubber cylinder (34) is installed in the frame-shaped groove (33). Four ventilation channels (35) are opened inside the floor body (1). The outer ends of the four ventilation channels (35) are connected to the rubber cylinder (34). A column groove (36) is opened in the middle of the upper end of the floor body (1). The inner ends of the four ventilation channels (35) are connected to the lower end of the column groove (36). Edge sealing unit (4): installed on the upper side of the perimeter of the floor body (1); The splicing unit (3) also includes a rubber column (37), an arc-shaped retaining ring is installed in the column groove (36), the rubber column (37) is installed in the column groove (36) and is engaged with the arc-shaped retaining ring, and a vertically penetrating air hole is opened in the middle of the rubber column (37); the edge sealing unit (4) includes an edge strip (41) and an arc groove (42), an edge strip (41) is installed on the upper side of all four sides of the floor body (1), and an arc groove (42) is opened on the upper side of all four sides of the floor body (1), and the arc groove (42) is located on the upper side of the edge strip (41); The edge sealing unit (4) also includes an I-shaped insert (43) and an arc strip (44). The lower right side of the I-shaped insert (43) is engaged with the edge strip (41). Both the left and right ends of the I-shaped insert (43) are provided with arc strips (44). The right arc strip (44) is engaged in the arc groove (42) on the left side of the floor body (1).

2. The easily assembled waterproof modular house floor structure according to claim 1, characterized in that: It also includes a patterned layer (5) and a resin layer (6). The patterned layer (5) is installed on the upper end of the floor body (1), and the resin layer (6) is installed on the upper end of the patterned layer (5).

3. The easily assembled waterproof modular house floor structure according to claim 2, characterized in that: It also includes inserts (7), and inserts (7) are installed at the lower end of the floor body (1) and the lower end of the connecting plate (32).

4. The method of using the easily assembled waterproof modular house floor structure according to claim 3, characterized in that, The following usage steps are included: S1. First, snap one end of the connecting plate (32) to the underside of another floor and install it on the concrete ground. When installing this floor, snap one side of the bottom edge of this floor to the other end of the connecting plate (32). When snapping, the clip on the connecting plate (32) snaps into the slot provided in the plate groove (31) so that the two floor pieces are tightly connected. When installed on the concrete, the circular lower groove (2), the floor body (1), and the insert (7) at the bottom of the connecting plate (32) can increase the contact area with the concrete, increase the adhesion, and achieve the initial splicing installation. S2. After the flooring is assembled, take out the rubber I-shaped insert (43) and attach the left and right sides of the lower end of the I-shaped insert (43) to the edge strip (41) of the two flooring units that are close to each other. When attaching, the arc strips (44) on the left and right sides of the I-shaped insert (43) can be attached into the arc groove (42) of the two flooring units that are close to each other. Then apply sealant to the gap between the upper side of the left and right ends of the I-shaped insert (43) and the two flooring units to achieve initial waterproofing. S3. Next, use an external basketball to insert an air needle into the air hole in the middle of the rubber column (37), and use an external air pump to pump air. The air can be delivered into the rubber cylinder (34) through four air channels (35), so that the rubber cylinder (34) is opened. When opened, it can fit tightly with the rubber cylinder (34) of another floor that is opened. On the one hand, it improves the tightness of the connection, and on the other hand, it can prevent water from seeping down and affecting the building. S4. Finally, grind and polish the upper surface of the resin layer (6) to improve the gloss of the upper surface of the floor. The resin layer (6) is made of resin mixture and solidification with appropriate hardness. Different patterns are drawn in the pattern layer (5), which improves the style of the floor and better meets the needs of customers.

Citation Information

Patent Citations

  • Combination concatenation formula floor

    CN205314456U

  • Top board waterproof seal structure of stone material curtain

    CN207244946U

  • Prefabricated wallboard joint structure and waterproof part

    CN210316028U

  • Stone-plastic floor

    CN212957427U