Double-layer insulation composite prefabricated wallboard

Abstract

The utility model relates to a double-layer insulation composite prefabricated wall plate, which comprises a rectangular prefabricated wall plate main body and a wall body outer frame around the rectangular prefabricated wall plate main body, a main body is formed by stacking an inner wall plate, a heat preservation filling layer and an outer wall plate, connecting pieces which are evenly distributed are arranged between the inner wall plate and the outer wall plate, each connecting piece comprises a connecting column and a connecting sleeve which are matched in an inserted connection mode, each connecting column is provided with a first sliding block with a spring, and each connecting sleeve is provided with a second sliding groove; and the first sliding block extends into the second sliding chute to form self-locking retaining after the first sliding block and the second sliding chute are inserted. A plurality of insertion block assemblies are arranged on the right side of the wall body outer frame and comprise insertion block bodies and sliding locking blocks capable of sliding along the guide columns, and grooves and extension grooves are correspondingly formed in the left side of the wall body outer frame; a containing cavity is formed in the rear portion of the inserting block assembly, the square sliding column and the pulling plate are driven through transmission of the nut and the bevel gear, the sliding locking block extends outwards and is clamped into the extending groove of the adjacent wall plate, and tight locking of the left wall plate and the right wall plate is achieved. The connecting strength of the inner layer and the outer layer of the wallboard is high, adjacent wallboards are tightly and stably spliced, and the overall heat preservation and waterproof performance is good.

Description

Technical Field

[0001] This utility model relates to a double Meiji thermal insulation composite prefabricated wall panel. Background Technology

[0002] With the development of industrialized construction, precast wall panels suitable for my country's building construction and seismic codes have emerged. Currently, precast wall panel components are manufactured in factories and mechanically installed on construction sites. For a description of the precast wall panel structure, see Chinese Patent CN201910783711.3.

[0003] Double Meiji thermal insulation composite precast wall panel is a new type of building wall material. It consists of two structural layers, an inner and an outer layer, and an insulation layer in the middle. The overall structure is similar to a sandwich, hence the name. This wall panel has the advantages of good thermal insulation performance, convenient construction, and high strength, and is widely used in various construction projects.

[0004] The existing technology has the following problems:

[0005] On the one hand, the lack of effective support between structural layers causes the wall panels to lose strength when subjected to certain pressures or external forces, making it difficult to meet the requirements of some building scenarios with high wall strength requirements. On the other hand, the existing splicing methods between wall panels are not perfect, resulting in poor splicing effects and easily leading to excessive gaps and loose connections. This not only affects the aesthetics of the wall but may also lead to a decrease in thermal insulation and waterproofing performance. Utility Model Content

[0006] The technical problem to be solved by this utility model is to provide a double Meiji thermal insulation composite prefabricated wall panel, which has sufficient strength and a tight and stable splicing effect.

[0007] To solve the above-mentioned technical problems, this utility model provides a double Meiji thermal insulation composite prefabricated wall panel;

[0008] It includes a rectangular prefabricated wall panel body arranged vertically with its length direction running left and right, and a circumferentially closed wall frame surrounding the four edges of the prefabricated wall panel body.

[0009] The precast wall panel body includes, from front to back, an inner wall panel, an insulation filling layer, and an outer wall panel stacked sequentially. The rear side of the outer wall panel is flush with the rear side of the outer wall frame, and the front side of the inner wall panel is flush with the front side of the outer wall frame. Several evenly arranged connectors are provided between the inner and outer wall panels. Each connector includes a first attachment for connecting to the outer wall panel and a second attachment for connecting to the inner wall panel. The first attachment is a horizontally arranged connecting column with its axis running front-to-back, and the second attachment is a horizontally arranged connecting sleeve with its axis running front-to-back. The connecting column and the connecting sleeve are inserted into each other. Several long, radially arranged sections are provided around the front of the connecting column. A strip-shaped first slide groove is provided. Several first slide grooves are evenly distributed at equal angles along the circumference of the connecting column. The side of the first slide groove closer to the core of the connecting column is defined as the inner side, and the side farther from the core of the connecting column is defined as the outer side. Each first slide groove is provided with a spring arranged radially along the connecting column. The inner end of the spring is fixed to the bottom of the first slide groove, and the outer end of the spring is connected to a first slider. The first slider and the first slide groove slide together along the length of the first slide groove. The front part of the outer side of the first slider is provided with a guide slope. At the position of the connecting sleeve, a second slide groove is provided at each first slide groove, which runs radially through the connecting sleeve and matches the first slide groove. A part of the outer side of the first slider extends into the second slide groove to form a lock.

[0010] The outer frame of the wall is provided with several insert components on its right side. These insert components are arranged at equal intervals along the vertical direction on the right side of the outer frame. Each insert component includes an insert body, which is a hollow rectangular block. The left side of the insert body is open. On the right side of the insert body, corresponding to the middle area of ​​its height direction, there are two elongated slots arranged symmetrically front to back. The two slots extend horizontally in the front and back directions, respectively. Each slot has a horizontal guide post running front to back. The front and back sides of the two slots extend to the front and back sides of the insert body, respectively. The right side of the two slots extends to the right side of the insert body. The left side is connected to the inner cavity of the insert body. Each of the two slots contains a sliding locking block that slides with the corresponding guide post. The sliding locking blocks are rectangular blocks. The right side of each sliding locking block is flush with the right side of the insert body. The front side of the front sliding locking block is flush with the front side of the insert body, and the rear side of the rear sliding locking block is flush with the rear side of the insert body. A receiving cavity is provided on the right side of the outer frame of the wall corresponding to each insert body. Each receiving cavity includes a square sliding groove, a shaft hole, and a first gear cavity connected sequentially from right to left. The square sliding groove runs horizontally. Each square sliding groove has a right side that slides with the corresponding guide post. The left side of the insert block body is open and directly opposite. A square sliding post is provided in the square sliding groove. The square sliding post and the square sliding groove slide in a left-right direction. A screw is provided in the shaft hole that matches the shaft hole. The left side of the square sliding post has a threaded hole that matches the screw. The right side of the screw is screwed to the left side of the square sliding post. A first bevel gear is provided in the first gear cavity. The shaft of the first bevel gear is fixedly connected to the left side of the screw. Two vertically arranged pull plates with a left-right length direction are provided on the right side of the square sliding post. The two pull plates are symmetrically arranged in the inner cavity of the insert block body. The left side of both pull plates is hinged to the right side of the square sliding post. The right sides of the two pull plates are respectively... The left side of the corresponding sliding lock block is hinged, and the hinge axis is vertical. The distance between the two pull plates along the front and back direction is smaller on the left and larger on the right. A second gear cavity is provided in front of each receiving cavity on the outer frame of the wall. Each second gear cavity is connected to the corresponding first gear cavity. A second bevel gear with the axis direction running in the front and back direction is provided in the second gear cavity. Each second bevel gear meshes with the corresponding first bevel gear. A coaxial nut is installed at the center of each second bevel gear shaft through the drive shaft. A recess is provided on the front side of the outer frame of the wall corresponding to each nut. The nut is located in the corresponding recess.

[0011] On the left side of the outer frame of the wall, there is a groove that matches the plug assembly at each plug assembly. On the right side of the groove, there are extension grooves extending in the front and back directions, and the size of the extension grooves matches the sliding lock block.

[0012] For the sake of simplicity, the double Meiji thermal insulation composite prefabricated wall panel described in this utility model will be referred to as "this wall panel" in the following description.

[0013] Instructions for using this wall panel:

[0014] Before the prefabricated wall panels are assembled, the front side of the outer wall panel is fixedly connected to the connecting column, and the rear side of the inner wall panel is fixedly connected to the connecting sleeve. Insulation filler is preset between the outer wall panel and the inner wall panel. The connecting column and the connecting sleeve are inserted together. At the beginning stage, the outer part of the first slider is exposed outside the first slide groove. During the insertion process, when the connecting sleeve contacts the first slider, the first slider retracts into the first slide groove under the action of the guide slope. At this time, the spring is compressed. When the first slider moves to be directly opposite the second slide groove, the first slider pops out radially and enters the second slide groove under the action of the spring force. At this moment, the connection and locking between the inner wall panel and the outer wall panel is completed.

[0015] When connecting two wall panels, insert the plug assembly on the left wall panel into the corresponding groove on the right wall panel, so that the outer frames of the two adjacent wall panels are completely flush. Then, use a wrench to turn all the nuts in the recesses in sequence. Each nut drives the corresponding second bevel gear to rotate. The second bevel gear drives the screw to rotate through the pre-meshed first bevel gear. At this time, the square sliding post screwed to the right of the screw is equivalent to a lead screw nut. Driven by the rotation of the screw, it moves parallel to the right. The two pull plates on the right side of the square sliding post are equivalent to a linkage mechanism, pushing the two sliding locking blocks to move forward and backward respectively. After displacement, the two sliding locking blocks extend into the corresponding extension slots to complete the locking.

[0016] Advantages of this wall panel:

[0017] 1. The connector structure enhances the connection strength between the exterior and interior wall panels. When either the exterior or interior wall panel is subjected to external pressure, the connector effectively disperses the stress, preventing strength reduction due to lack of support between the panels. This better meets the requirements of building scenarios with high wall strength requirements. The locking structure of the connecting column and sleeve self-locks after insertion, making installation convenient and operation simple.

[0018] 2. When connecting two adjacent wall panels, not only are the insert components positioned by the convex-concave fit of the groove, but the sliding locking block, which is originally flush with the insert body, is pushed into the extension groove by the drive mechanism embedded on the right side of the wall frame. The two sliding locking blocks are like locking pins, which play a role in preventing backlash and making the connection tighter. Since the insert components are arranged at equal intervals along the vertical direction on the right side of the wall frame, the gap between the two is uniform and the overall force is balanced. This solves the problem of excessive gaps and loose connections in the existing wall panel splicing method. It not only improves the aesthetics of the wall, but also ensures the thermal insulation and waterproof performance of the wall.

[0019] To achieve better performance of this utility model, the preferred solution is as follows:

[0020] Preferably, the second slide groove is provided with a second slider, which slides radially with the second slide groove. The outer side of the first slider is in contact with the inner side of the second slider. The front and rear sides of the second slide groove are provided with limiting grooves. The front and rear sides of the second slider are respectively provided with limiting ear plates that extend into the corresponding limiting grooves and match them.

[0021] During transportation or installation, if subjected to external forces such as collisions, the second slider can provide some protection and stability to the first slider, preventing the first slider from accidentally coming off and further enhancing the stability of the connection.

[0022] Preferably, each recess is provided with a cover plate that matches the recess.

[0023] The cover plate not only serves a decorative purpose, but also protects components such as nuts, preventing them from being affected by external environmental interference and thus maintaining their function. Attached Figure Description

[0024] Figure 1 This is a structural schematic diagram of the wall panel;

[0025] Figure 2 This is a structural schematic diagram of the main body of the precast wall panel.

[0026] Figure 3 This is a cross-sectional structural diagram of the wall panel connector;

[0027] Figure 4 This is a cross-sectional structural diagram of two wall panel insert components mating with a groove;

[0028] Figure 5 This is a cross-sectional structural diagram of the wall panel insert assembly. Detailed Implementation

[0029] See Figures 1-5 A double-Meiji thermal insulation composite prefabricated wall panel; including a rectangular prefabricated wall panel body 1 arranged vertically and with its length direction running left and right, and a circumferentially closed wall frame 2 surrounding the four edges of the prefabricated wall panel body 1 at the top, bottom, left and right.

[0030] The precast wall panel body 1 includes an inner wall panel 11, an insulation filling layer 12, and an outer wall panel 13 stacked sequentially from front to back. The rear side of the outer wall panel 13 is flush with the rear side of the outer wall frame 2, and the front side of the inner wall panel 11 is flush with the front side of the outer wall frame 2. Several evenly arranged connectors 3 are provided between the inner wall panel 11 and the outer wall panel 13. Each connector 3 includes a first attachment for connecting to the outer wall panel 13 and a second attachment for connecting to the inner wall panel 11. The first attachment is a horizontally arranged connecting column 31 with its axis running front to back, and the second attachment is a horizontally arranged connecting sleeve 32 with its axis running front to back. The connecting column 31 and the connecting sleeve 32 are inserted into each other. Several elongated first grooves 5311 are provided circumferentially around the front of the connecting column 31, arranged radially along the connecting column 31. The first slide groove 5311 is evenly distributed at equal angles along the circumference of the connecting column 31. The side closer to the axis of the connecting column 31 is the inner side, and the side farther away from the axis of the connecting column 31 is the outer side. Each first slide groove 5311 is provided with a spring 312 arranged radially along the connecting column 31. The inner end of the spring 312 is fixed to the bottom of the first slide groove 5311, and the outer end of the spring 312 is connected to a first slider 313. The first slider 313 slides in cooperation with the first slide groove 5311 along its length. The front part of the outer side of the first slider 313 is provided with a guide slope 314. At the position of the connecting sleeve 32, corresponding to each first slide groove 5311, there is a second slide groove 5321 that runs radially through the connecting sleeve 32 and matches the first slide groove 5311. A part of the outer side of the first slider 313 extends into the second slide groove 5321 to form a lock.

[0031] The second slide groove 5321 is provided with a second slider 322. The second slider 322 slides radially with the second slide groove 5321. The outer side of the first slider 313 is in contact with the inner side of the second slider 322. The front and rear sides of the second slide groove 5321 are provided with limiting grooves 323. The front and rear sides of the second slider 322 are respectively provided with limiting ear plates 324 that extend into the corresponding limiting grooves 323 and match them.

[0032] The outer wall frame 2 has several insert components 4 on its right side. These insert components 4 are arranged at equal vertical intervals on the right side of the outer wall frame 2. Each insert component 4 includes an insert body 41, which is a hollow rectangular block. The left side of the insert body 41 is open. On the right side of the insert body 41, corresponding to the middle area of ​​its height direction, there are two elongated slots 42 arranged symmetrically front to back. The two slots 42 extend horizontally in the front and back directions, respectively. Each slot 42 has a horizontal guide post 43 running front to back. The front and back sides of the two slots 42 extend to the front and back sides of the insert body 41, respectively. The right side of the two slots 42 extends to the right side of the insert body 41. The left side of the two slots 42 is connected to the insert body 41. The inner cavities are interconnected, and each of the two slots 42 is provided with a sliding locking block 44 that slides in cooperation with the corresponding guide post 43. The sliding locking block 44 is a rectangular block. The right side of the two sliding locking blocks 44 is flush with the right side of the insert body 41. The front side of the sliding locking block 44 is flush with the front side of the insert body 41, and the rear side of the sliding locking block 44 is flush with the rear side of the insert body 41. A receiving cavity is provided on the right side of the outer frame 2 corresponding to each insert body 41. The receiving cavity includes a square sliding groove 5, a shaft hole 6, and a first gear cavity 7 connected sequentially from right to left. The square sliding groove 5 runs horizontally. The right side of each square sliding groove 5 is directly opposite the left open side of the corresponding insert body 41. The device includes a square sliding column 51, which slides in a left-right direction with a square sliding groove 5. A screw 61, matching the shaft hole 6, is located within the shaft hole 6. A threaded hole matching the screw 61 is located on the left side of the square sliding column 51. The right side of the screw 61 is screwed to the left side of the square sliding column 51. A first bevel gear 71 is located within the first gear cavity 7, with its shaft fixedly connected to the left side of the screw 61. Two vertically arranged pull plates 52, extending left-right, are located on the right side of the square sliding column 51. These two pull plates 52 are symmetrically arranged symmetrically in the inner cavity of the insert block body 41. The left sides of both pull plates 52 are hinged to the right side of the square sliding column 51, and the right sides of both pull plates 52 are respectively hinged to the left side of the corresponding sliding locking block 44. The hinge shaft... All are vertically oriented. The distance between the two pull plates 52 along the front-back direction is smaller on the left and larger on the right. A second gear cavity 8 is provided in front of each receiving cavity on the outer frame 2 of the wall. Each second gear cavity 8 is connected to the corresponding first gear cavity 7. A second bevel gear 81 with the axis direction running front-back is provided in the second gear cavity 8. Each second bevel gear 81 meshes with the corresponding first bevel gear 71. A coaxial nut 83 is installed at the axis of each second bevel gear 81 through a drive shaft 82. A recess 84 is provided on the front side of the outer frame 2 corresponding to each nut 83. The nut 83 is located in the corresponding recess 84. A cover plate 85 matching the recess 84 is provided at each recess 84.

[0033] On the left side of the outer frame 2 of the wall, there is a groove 9 that matches the plug assembly 4 at each plug assembly 4. The right side of the groove 9 has extension grooves 91 extending in the front and back directions, and the size of the extension grooves 91 matches the sliding lock block 44.

[0034] Instructions for using this wall panel:

[0035] Before the prefabricated wall panels are assembled, the front side of the outer wall panel 13 is fixedly connected to the connecting column 31, and the rear side of the inner wall panel 11 is fixedly connected to the connecting sleeve 32. Insulation filler is preset between the outer wall panel 13 and the inner wall panel 11. The connecting column 31 and the connecting sleeve 32 are inserted together. At the beginning stage, the outer part of the first slider 313 is exposed outside the first slide groove 5311. During the insertion process, when the connecting sleeve 32 contacts the first slider 313, the first slider 313 retracts into the first slide groove 5311 under the action of the guide slope 314. At this time, the spring 312 is compressed. When the first slider 313 moves to be directly opposite the second slide groove 5321, the first slider 313 pops out radially and enters the second slide groove 5321 under the action of the spring force of the spring 312. At this moment, the connection and locking between the inner wall panel 11 and the outer wall panel 13 is completed.

[0036] When connecting two wall panels, insert the plug assembly 4 on the left wall panel into the groove 9 on the right wall panel, so that the outer frame 2 of the two adjacent wall panels are completely in contact. Then, use a wrench to turn all the nuts 83 in the recesses 84 in sequence. Each nut 83 drives the corresponding second bevel gear 81 to rotate. The second bevel gear 81 drives the screw 61 to rotate through the pre-meshed first bevel gear 71. At this time, the square sliding post 51 screwed to the right of the screw 61 is equivalent to the screw nut 83. Driven by the rotation of the screw 61, it moves parallel to the right. The two pull plates 52 on the right side of the square sliding post 51 are equivalent to the linkage mechanism, pushing the two sliding locking blocks 44 to move forward and backward respectively. After displacement, the two sliding locking blocks 44 extend into the corresponding extension grooves 91 to complete the locking.

[0037] Advantages of this wall panel:

[0038] 1. The connector 3 structure enhances the connection strength between the outer wall panel 13 and the inner wall panel 11. When the outer wall panel 13 or the inner wall panel 11 is subjected to external pressure, the connector 3 can effectively disperse the stress, avoiding the problem of strength reduction due to lack of support between the outer wall panel 13 and the inner wall panel 11. This better meets the requirements of building scenarios with high wall strength requirements. The locking structure of the connecting column 31 and the connecting sleeve 32 can self-lock and prevent backflow after insertion, making installation convenient and operation simple.

[0039] 2. When two adjacent wall panels are connected, not only is the positioning achieved through the convex-concave fit between the insert component 4 and the groove 9, but also the sliding locking block 44, which is originally flush with the insert body 41, is pushed into the extension groove 91 by the drive mechanism embedded on the right side of the outer frame 2 of the wall. The two sliding locking blocks 44 are equivalent to locking pins, which play a role in preventing backlash and making the connection tighter. Furthermore, since the insert component 4 is arranged at equal intervals along the vertical direction on the right side of the outer frame 2 of the wall, the gap between the two is uniform and the overall force is balanced. This solves the problem of excessive gaps and loose connections in the existing wall panel splicing method, which not only improves the aesthetics of the wall, but also ensures the thermal insulation and waterproof performance of the wall.

[0040] During transportation or installation, if subjected to external forces such as collisions, the second slider 322 can provide certain protection and stability to the first slider 313, preventing the first slider 313 from accidentally coming off and further enhancing the stability of the connection.

[0041] The cover plate 85 not only serves a decorative purpose, but also protects components such as the nut 83, preventing them from being affected by external environmental interference and thus maintaining their function.

Claims

1. A double-Meiji thermal insulation composite prefabricated wall panel, characterized in that: It includes a rectangular prefabricated wall panel body arranged vertically with its length direction running left and right, and a circumferentially closed wall frame surrounding the four edges of the prefabricated wall panel body. The precast wall panel body includes, from front to back, an inner wall panel, an insulation filling layer, and an outer wall panel stacked sequentially. The rear side of the outer wall panel is flush with the rear side of the outer wall frame, and the front side of the inner wall panel is flush with the front side of the outer wall frame. Several evenly arranged connectors are provided between the inner and outer wall panels. Each connector includes a first attachment for connecting to the outer wall panel and a second attachment for connecting to the inner wall panel. The first attachment is a horizontally arranged connecting column with its axis running front-to-back, and the second attachment is a horizontally arranged connecting sleeve with its axis running front-to-back. The connecting column and the connecting sleeve are inserted into each other. Several long, radially arranged sections are provided around the front of the connecting column. A strip-shaped first slide groove is provided. Several first slide grooves are evenly distributed at equal angles along the circumference of the connecting column. The side of the first slide groove closer to the core of the connecting column is defined as the inner side, and the side farther from the core of the connecting column is defined as the outer side. Each first slide groove is provided with a spring arranged radially along the connecting column. The inner end of the spring is fixed to the bottom of the first slide groove, and the outer end of the spring is connected to a first slider. The first slider and the first slide groove slide together along the length of the first slide groove. The front part of the outer side of the first slider is provided with a guide slope. At the position of the connecting sleeve, a second slide groove is provided at each first slide groove, which runs radially through the connecting sleeve and matches the first slide groove. A part of the outer side of the first slider extends into the second slide groove to form a lock. The outer frame of the wall is provided with several insert components on its right side. These insert components are arranged at equal intervals along the vertical direction on the right side of the outer frame. Each insert component includes an insert body, which is a hollow rectangular block. The left side of the insert body is open. On the right side of the insert body, corresponding to the middle area of ​​its height direction, there are two elongated slots arranged symmetrically front to back. The two slots extend horizontally in the front and back directions, respectively. Each slot has a horizontal guide post running front to back. The front and back sides of the two slots extend to the front and back sides of the insert body, respectively. The right side of the two slots extends to the right side of the insert body. The left side is connected to the inner cavity of the insert body. Each of the two slots contains a sliding locking block that slides with the corresponding guide post. The sliding locking blocks are rectangular blocks. The right side of each sliding locking block is flush with the right side of the insert body. The front side of the front sliding locking block is flush with the front side of the insert body, and the rear side of the rear sliding locking block is flush with the rear side of the insert body. A receiving cavity is provided on the right side of the outer frame of the wall corresponding to each insert body. Each receiving cavity includes a square sliding groove, a shaft hole, and a first gear cavity connected sequentially from right to left. The square sliding groove runs horizontally. Each square sliding groove has a right side that slides with the corresponding guide post. The left side of the insert block body is open and directly opposite. A square sliding post is provided in the square sliding groove. The square sliding post and the square sliding groove slide in a left-right direction. A screw is provided in the shaft hole that matches the shaft hole. The left side of the square sliding post has a threaded hole that matches the screw. The right side of the screw is screwed to the left side of the square sliding post. A first bevel gear is provided in the first gear cavity. The shaft of the first bevel gear is fixedly connected to the left side of the screw. Two vertically arranged pull plates with a left-right length direction are provided on the right side of the square sliding post. The two pull plates are symmetrically arranged in the inner cavity of the insert block body. The left side of both pull plates is hinged to the right side of the square sliding post. The right sides of the two pull plates are respectively... The left side of the corresponding sliding lock block is hinged, and the hinge axis is vertical. The distance between the two pull plates along the front and back direction is smaller on the left and larger on the right. A second gear cavity is provided in front of each receiving cavity on the outer frame of the wall. Each second gear cavity is connected to the corresponding first gear cavity. A second bevel gear with the axis direction running in the front and back direction is provided in the second gear cavity. Each second bevel gear meshes with the corresponding first bevel gear. A coaxial nut is installed at the center of each second bevel gear shaft through the drive shaft. A recess is provided on the front side of the outer frame of the wall corresponding to each nut. The nut is located in the corresponding recess. On the left side of the outer frame of the wall, there is a groove that matches the plug assembly at each plug assembly. On the right side of the groove, there are extension grooves extending in the front and back directions, and the size of the extension grooves matches the sliding lock block.

2. The double-Meiji thermal insulation composite prefabricated wall panel according to claim 1, characterized in that: The second slide groove is provided with a second slider, which slides radially with the second slide groove. The outer side of the first slider is in contact with the inner side of the second slider. The front and rear sides of the second slide groove are provided with limiting grooves. The front and rear sides of the second slider are respectively provided with limiting ear plates that extend into the corresponding limiting grooves and match them.

3. The double-Meiji thermal insulation composite prefabricated wall panel according to claim 1, characterized in that: Each recess is provided with a cover plate that matches the recess.

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