Small connecting box for tying plain round steel bars of self-heat-preservation system

Abstract

The invention provides a small connecting box for tying plain round steel bars of a self-heat-preservation system. The small connecting box comprises a box body, a box cover and a height difference pad body. A plurality of steel bar groove bodies are formed in the box body and the box cover and penetrate through the end faces of the two sides of the box body and the end faces of the two sides of the box cover respectively. One ends of the two sections of steel bars are embedded in mortar joints of the inner leaf wall and the outer leaf wall respectively, the other ends of the two sections of steel bars are inserted into the two steel bar grooves respectively, the box cover covers the box body in a matched mode to form a connecting box body, and the other ends of the two sections of steel bars are connected through the connecting box body; and the height difference pad body is embedded in the steel bar groove body, so that the two sections of steel bars are horizontally tied between the connecting box main body and the inner wall and between the connecting box main body and the outer wall respectively. The invention relates to the technical field of building facade construction, and can solve the problems that in the prior art, two sections of reinforcing steel bars are staggered and cannot be accurately butted, the reinforcing steel bar welding amount is large, and a conventional sleeve is not suitable for plain round reinforcing steel bar threading.

Description

Technical Field

[0001] This invention relates to the field of building facade construction technology, and in particular to a small connecting box for tying plain round steel bars in a self-insulating system. Background Technology

[0002] The red brick exterior wall is a self-insulating exterior wall system that connects red bricks in the outer leaf wall and autoclaved aerated concrete blocks in the inner leaf wall via a steel mesh. The dimensions of the autoclaved aerated concrete blocks in the inner leaf wall are 600mm (length) × 250mm (width) × 200mm (thickness), and the dimensions of the red bricks in the outer leaf wall are 240mm (length) × 115mm (width) × 53mm (thickness). During construction, two L-shaped steel bars 1 are embedded in the mortar joints of the inner leaf wall 2 and the outer leaf wall 3, respectively. The two L-shaped steel bars 1 are then threaded through sleeves and welded together to form a complete horizontal load-bearing system, as shown in the attached diagram. Figure 1 and attached Figure 2 As shown.

[0003] Because the brick thicknesses of the inner and outer leaf walls differ, precise alignment is required through bricklaying. For example, the thickness of two courses of autoclaved aerated concrete blocks plus mortar joints must align with the thickness of seven courses of red bricks plus mortar joints, with a reinforcing bar 1 every 410mm. However, in actual construction, errors in bricklaying and construction are inevitable, causing the two L-shaped reinforcing bars 1 to misalign and fail to connect precisely. This necessitates bending one section of the reinforcing bar twice and welding it to the other section, as shown in the attached diagram. Figure 3 As shown, the secondary processing of steel bars involves a large amount of work; and the amount of red bricks used in the exterior facade construction is large (some projects involve more than 2 million red bricks). The amount of steel bar welding is also large, resulting in low construction efficiency, high requirements for process control, and inconsistent welding quality. In addition, 6mm plain round steel bars are usually used for steel bars, and conventional sleeves are not applicable.

[0004] Therefore, there is a need for a small connecting box for tying plain round steel bars in a self-insulating system, which can solve the problems in the prior art where two sections of steel bars are misaligned and cannot be accurately connected, the amount of steel bar welding is large, and conventional sleeves are not suitable for threading plain round steel bars. Summary of the Invention

[0005] The purpose of this invention is to provide a small connecting box for tying plain round steel bars in a self-insulating system, which can solve the problems in the prior art such as the inability to accurately connect two sections of steel bars due to misalignment, the large amount of steel bar welding, and the unsuitability of conventional sleeves for threading plain round steel bars.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows:

[0007] A small connecting box for tying plain round steel bars in a self-insulating system includes: a box body, a box cover, and a height difference pad; several steel bar grooves are formed inside the box body and the box cover, and the several steel bar grooves pass through the two end faces of the box body and the box cover respectively; one end of two steel bars is embedded in the mortar joint of the inner leaf wall and the outer leaf wall respectively, and the other end of the two steel bars is inserted into the two steel bar grooves respectively; the box cover matches and covers the box body to form the main body of the connecting box, so that the other ends of the two steel bars are connected through the main body of the connecting box; the height difference pad is embedded in the steel bar groove, so that the two steel bars are horizontally tied between the main body of the connecting box and the inner leaf wall and between the main body of the connecting box and the outer leaf wall respectively.

[0008] The side of the rebar groove is formed with an extension groove, which forms an acute angle with the rebar groove. The other end of the rebar is bent to form an end bend that matches the acute angle. The other end of the rebar is embedded in the rebar groove, and the end bend of the rebar is embedded in the extension groove, so that the other end of the rebar is connected and fixed to the main body of the connecting box.

[0009] The main body of the connecting box is symmetrically provided with two steel bar grooves, and the number of extension grooves is the same as the number of steel bar grooves; the length directions of the two steel bar grooves are on the same straight line, forming a straight connecting box.

[0010] The main body of the connecting box is symmetrically provided with four steel bar grooves, and the number of extension grooves is the same as the number of steel bar grooves; two of the steel bar grooves are arranged along the length direction of the main body of the connecting box, and the other two steel bar grooves are arranged along the width direction of the main body of the connecting box, forming a cross-shaped connecting box.

[0011] The width of the steel bar groove and the extension groove is consistent with the diameter of the steel bar.

[0012] The elevation difference pad is composed of one or more pads. One or more pads are embedded in the steel bar groove and form a steel bar interlayer in the steel bar groove. The other end of the steel bar is inserted into the steel bar interlayer.

[0013] The height difference pad has a through hole at the end away from the side wall of the box, and a limiting shaft is provided in the end of the steel bar groove away from the side wall of the box. The limiting shaft passes through the height difference pad through the through hole.

[0014] The limiting shaft is fitted with an anti-collision sleeve, and the end of the reinforcing bar can be perpendicularly abutted against the anti-collision sleeve.

[0015] The outer wall of the box is provided with a number of box buckles at intervals, and the outer wall of the lid is provided with a number of lid buckles at intervals. The box buckles and lid buckles are matched and fastened together.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] 1. This invention features a box body and a box cover. One end of each of the two steel bars is pre-embedded in the inner and outer leaf walls, while the other end of each steel bar is embedded in the steel bar groove of the box body and bent and embedded in the extension groove. This ensures a reliable connection between the ends of the steel bars and the main body of the connecting box, preventing them from loosening. This ensures that the two steel bars are firmly connected through the main body of the connecting box, and the connection node can achieve the strength of a traditional welded connection. No sleeve threading or welding is required, making the construction process simple and convenient, greatly improving construction efficiency, and reducing the requirements for process level while ensuring construction quality.

[0018] 2. This invention features height difference pads embedded within the rebar groove. By combining pads in different positions and quantities, a rebar interlayer is formed within the rebar groove to match and embed plain round rebars, improving the reliability of the connection between the rebars and the box body. It also accommodates the height difference between two rebar sections, ensuring an effective connection between the two sections without requiring secondary processing of the rebars, thus solving the problem of rebar misalignment and inaccurate docking. Simultaneously, the rubber height difference pads provide some shock absorption, further enhancing the stability of the rebar connection nodes.

[0019] 3. The steel bar groove of the present invention is arranged in a straight line or a cross shape, which can meet the connection of two steel bars on the same straight line, as well as the connection of two steel bars perpendicular to each other, thereby forming a steel bar tie mesh between the inner and outer leaf walls, which meets the tie design requirements between the inner and outer leaf walls of the self-insulating system. Attached Figure Description

[0020] The above and other objects, features and advantages of this disclosure will become more apparent from the accompanying drawings, in which like reference numerals generally denote like parts.

[0021] Figure 1 It is a cross-sectional view of the reinforcement connection between the outer leaf wall and the inner leaf wall in the existing technology;

[0022] Figure 2 It is a longitudinal section view of the steel reinforcement connection between the outer leaf wall and the inner leaf wall in the existing technology;

[0023] Figure 3 This is a schematic diagram of the secondary processing and welding of the reinforcing bars of the outer leaf wall and the inner leaf wall in the existing technology;

[0024] Figure 4 This is an open top view (one-line connecting box) of a small connecting box for tying plain round steel bars in a self-insulating system according to the present invention;

[0025] Figure 5 This is a cross-sectional view of a small connecting box (a straight connecting box) for tying plain round steel bars in a self-insulating system according to the present invention.

[0026] Figure 6 This is a side view of a small connecting box for tying plain round steel bars in a self-insulating system according to the present invention;

[0027] Figure 7 This is a top view (cross-shaped connecting box) of a small connecting box for tying plain round steel bars in a self-insulating system according to the present invention.

[0028] Figure 8 This is a schematic diagram of a steel bar connection for a small connecting box used for tying plain round steel bars in a self-insulating system according to the present invention (the two steel bars have no height difference);

[0029] Figure 9 This is a schematic diagram of another steel bar connection for a small connecting box for tying plain round steel bars in a self-insulating system according to the present invention (the two steel bars have a height difference);

[0030] Figure 10 This is a schematic diagram of the construction of a steel reinforcement mesh for a small connecting box used for tying plain round steel bars in a self-insulating system, according to the present invention.

[0031] In the diagram, 1 is the reinforcing bar, 2 is the inner leaf wall, 3 is the outer leaf wall, 4 is the box body, 41 is the reinforcing bar channel, 42 is the extension channel, 43 is the box buckle, 44 is the reinforcing bar interlayer, 5 is the box cover, 51 is the cover buckle, 6 is the height difference pad, 7 is the limiting shaft, and 71 is the anti-collision sleeve. Detailed Implementation

[0032] The following detailed description, in conjunction with the accompanying drawings and specific embodiments, provides a small connecting box for tying plain round steel bars in a self-insulating system, according to the present invention. The advantages and features of the present invention will become clearer from the following description and claims. It should be noted that the drawings are all in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of the present invention.

[0033] Please see the appendix Figure 3 To be continued Figure 10 A small connecting box for tying plain round steel bars in a self-insulating system includes a box body 4, a box cover 5, and a height difference pad 6. Several steel bar grooves 41 are formed inside both the box body 4 and the box cover 5, and these grooves 41 penetrate both ends of the box body 4 and the box cover 5. One end of two steel bars 1 is embedded in the mortar joints of the inner leaf wall 2 and the outer leaf wall 3, respectively, and the other ends of the two steel bars 1 are inserted into the two steel bar grooves 41. The box cover 5 covers the box body 4 to form the main body of the connecting box, allowing the other ends of the two steel bars 1 to be connected through the main body of the connecting box. The height difference pad 6 is embedded in the steel bar grooves 41, allowing the two steel bars 1 to be horizontally tied between the main body of the connecting box and the inner leaf wall 2, and between the main body of the connecting box and the outer leaf wall 3, respectively.

[0034] Preferably, the height difference pad 6 can be made of rubber material. The height difference pad 6 of different thicknesses can adapt to the height difference between the two sections of steel bar 1, so as to ensure that the two sections of steel bar 1 can be accurately connected and horizontally tied between the inner leaf wall 2 and the outer leaf wall 3, without the need for secondary processing of the two sections of steel bar 1.

[0035] The other end of the reinforcing bar 1 is embedded in the reinforcing bar groove 41. The number of reinforcing bar grooves 41 can be adjusted according to actual needs. According to the connection design requirements of the reinforcing bar 1 between the inner leaf wall 2 and the outer leaf wall 3, it is preferable to set two or four reinforcing bar grooves 41. The number and arrangement of the reinforcing bar grooves 41 in the box body 4 match the number and arrangement of the reinforcing bar grooves 41 in the box cover 5, so as to ensure that after the box cover 5 is closed on the box body 4, the several reinforcing bar grooves 41 inside it are connected one by one, which facilitates the embedding of the reinforcing bar 1 in the connecting box body.

[0036] After the cover 5 is fastened onto the box body 4, the other ends of the two steel bars 1 are sealed within the steel bar groove 41 connecting the box body. This eliminates the need for welding to connect the other ends of the two steel bars 1, significantly improving construction efficiency and reducing the requirements for craftsmanship. Furthermore, it eliminates the need for threading the connection points of the steel bars 1, solving the problem that conventional sleeves cannot be used with 6mm plain round steel bars. This allows 6mm plain round steel bars to be used for the connection between the inner leaf wall 2 and the outer leaf wall 3 of the self-insulating system.

[0037] Please see the appendix Figure 4 and attached Figure 7 The side of the steel bar groove 41 is formed with an extension groove 42, and the extension groove 42 forms an acute angle with the steel bar groove 41; the other end of the steel bar 1 is bent to form an end bend section that matches the acute angle, and the other end of the steel bar 1 is embedded in the steel bar groove 41, and the end bend section of the steel bar 1 is embedded in the extension groove 42, so that the other end of the steel bar 1 is connected and fixed to the main body of the connecting box.

[0038] By bending the other end of the reinforcing bar 1 into a V-shaped structure at a certain angle and matching the extension groove 42 and the reinforcing bar groove 41, the other end of the reinforcing bar 1 can be stably and reliably locked in the main body of the connecting box and will not come out when under force. Thus, the other ends of the two sections of reinforcing bar 1 can be reliably connected through the main body of the connecting box, which can replace the traditional welding connection and speed up the construction progress.

[0039] Please see the appendix Figure 4 The main body of the connecting box is provided with two symmetrical steel bar grooves 41, and the number of extension grooves 42 is the same as the number of steel bar grooves 41; the length directions of the two steel bar grooves 41 are on the same straight line, forming a straight connecting box.

[0040] Preferably, the dimensions of the box body 4 of the straight-line connector box are 13mm×50mm×22mm, and the height of the cover 5 is 4mm; the straight-line connector box can be used to connect two sections of steel bars 1 on the same straight line.

[0041] Please see the appendix Figure 7 The main body of the connecting box is symmetrically provided with four steel bar grooves 41, and the number of extension grooves 42 is the same as the number of steel bar grooves 41; two of the steel bar grooves 41 are arranged along the length direction of the main body of the connecting box, and the other two steel bar grooves 41 are arranged along the width direction of the main body of the connecting box, forming a cross-shaped connecting box.

[0042] Preferably, the dimensions of the box body 4 of the cross-shaped connecting box are 50mm×75mm×22mm, and the height of the cover 5 is 4mm. The cross-shaped connecting box can be used to connect two sections of steel bars 1 on the same straight line, or to connect two sections of steel bars 1 arranged perpendicularly, so as to meet the connection requirements of steel bars 1 arranged in different directions, thereby forming a tie steel mesh between the inner and outer leaf walls.

[0043] The width of the groove body 41 and the extension groove body 42 is the same as the diameter of the reinforcing bar 1, which is 6mm.

[0044] In the connection between the inner and outer leaf walls of the self-insulating system, the reinforcing bar 1 is usually made of 6mm plain round steel bar. The groove width of the reinforcing bar groove 41 and the extension groove 42 is designed to be 6mm, which is consistent with the diameter of the reinforcing bar 1. This ensures that the reinforcing bar 1 is properly secured in the reinforcing bar groove 41 and the extension groove 42 without loosening, thereby improving the connection reliability between the reinforcing bar 1 and the main body of the connecting box. This, in turn, ensures the connection strength of the two sections of reinforcing bar 1, enabling it to achieve the same connection strength as the traditional welded connection and meet the stress requirements of the connection.

[0045] Please see the appendix Figure 5 The elevation difference pad 6 is composed of one or more pads. One or more pads are embedded in the steel bar groove 41 and form a steel bar interlayer 44 in the steel bar groove 41. The other end of the steel bar 1 is inserted into the steel bar interlayer 44.

[0046] Preferably, the height of the rebar groove 41 is 18mm, the thickness of each pad is 6mm, and two pads can be set in the rebar groove 41 to form a rebar interlayer 44 with a height consistent with the diameter of the rebar 1, i.e., 6mm, thereby ensuring the stable insertion of the rebar 1 in the rebar interlayer 44.

[0047] The two pads can be stacked or spaced apart. When stacked, a reinforcing steel interlayer 44 can be formed at the top or bottom of the reinforcing steel groove 41, as shown in the attached diagram. Figure 9 As shown, when spaced out, a reinforcing bar interlayer 44 can be formed in the middle of the reinforcing bar groove 41, as shown in the attached diagram. Figure 8As shown, this allows for the adaptation of steel bars 1 at different pre-embedded heights, ensuring that steel bars 1 are horizontal and straight without the need for secondary processing.

[0048] The rubber pad can provide some shock absorption and better fix the reinforcing bar 1. Combined with the reinforcing bar interlayer 44 with the same diameter as the reinforcing bar 1, it can effectively reduce the slippage of the reinforcing bar 1, thereby ensuring the reliable and stable connection between the two sections of reinforcing bar 1.

[0049] In actual construction, the height difference pad 6 may not be set up. The height of the pre-embedded height of the steel bar 1 can be controlled by the height of the steel bar groove 41 inside the main body of the connecting box.

[0050] Please see the appendix Figure 4 The height difference pad 6 has a through hole (not shown in the figure) at one end away from the side wall of the box body 4, and a limiting shaft 7 is provided in the end of the steel bar groove 41 away from the side wall of the box body 4. The limiting shaft 7 passes through the height difference pad 6 through the through hole.

[0051] Preferably, the limiting shaft 7 can be a metal shaft, used to insert the height difference pad 6, so that the height difference pad 6 can be stably embedded in the steel bar groove 41 and is not easy to slip or fall out.

[0052] Please see the appendix Figure 4 The limiting shaft 7 is fitted with an anti-collision sleeve 71, and the end of the steel bar 1 can be perpendicularly abutted against the anti-collision sleeve 71.

[0053] Preferably, the anti-collision sleeve 71 can be made of rubber material to reduce the collision and friction between the end of the steel bar 1 and the limiting shaft 7, thereby playing a role in preventing impact.

[0054] Please see the appendix Figure 4 Appendix Figure 6 and attached Figure 7 The outer wall of the box body 4 is provided with a number of box buckles 43 at intervals, and the outer wall of the box cover 5 is provided with a number of cover buckles 51 at intervals. The box buckles 43 and the cover buckles 51 are matched and fastened together.

[0055] Preferably, one end of the box body 4 and the box cover 5 can be connected by a hinge, and the other end of the box body 4 and the box cover 5 can be connected by two sets of box buckles 43 and cover buckles 51; or, both ends of the box body 4 and the box cover 5 can be connected by two sets of box buckles 43 and cover buckles 51.

[0056] The number of sets and structural forms of the box buckle 43 and the lid buckle 51 can be adapted to the actual connection requirements. The box buckle 43 and the lid buckle 51 are conventional connection structures between the box body 4 and the box lid 5 in this field, and their specific structural forms will not be listed here.

[0057] Please see the appendix Figure 4 To be continued Figure 10 The construction method and working principle of the present invention are as follows:

[0058] Step 1: Construct the inner leaf wall 2 and outer leaf wall 3 of the self-insulating system according to the wall design drawings, and pre-embed one end of the steel bar 1 in the mortar joint between the inner leaf wall 2 and the outer leaf wall 3.

[0059] The construction of the inner leaf wall 2 and the outer leaf wall 3, as well as the pre-embedding of the reinforcing steel 1, were carried out using conventional construction techniques, which will not be elaborated here.

[0060] Step 2: Bend the other end of the reinforcing bar 1 by 150° so that it matches the 30° angle between the extension groove 42 and the reinforcing bar groove 41.

[0061] Step 3: Select the model of the main body of the connector box according to the position and connection direction of the rebar 1, i.e., a straight connector box or a cross connector box.

[0062] Step 4: Place the other ends of the two steel bars 1, which are embedded at the same height in the inner leaf wall 2 and the outer leaf wall 3, into the steel bar groove 41 of the box body 4 respectively, and place the bent end of the steel bar 1 into the extension groove 42.

[0063] Based on the relative height of the two reinforcing bars 1, the reinforcing bars 1 are placed in different positions of the two pads in the reinforcing bar groove 41 to form a height difference. This allows one reinforcing bar 1 to be horizontally tied between the reinforcing bar interlayer 44 and the inner leaf wall 2, and the other reinforcing bar 1 to be horizontally tied between the reinforcing bar interlayer 44 and the outer leaf wall 3. This accommodates the height difference between the two reinforcing bars 1 caused by factors such as brick arrangement and construction errors.

[0064] Step 5: Cover the box body 4 with the lid 5.

[0065] Step 6: Lock the box body together with the cover buckle 51 using the box buckle 43, and connect the other ends of the two steel bars 1 together.

[0066] Step 7: Repeat steps 2 to 6 to complete the connection of all steel bars 1 between the inner leaf wall 2 and the outer leaf wall 3.

[0067] At complex structural nodes, a combination of straight-line and cross-shaped connectors can be used to connect multiple reinforcing bars to form a reinforcing mesh, thus meeting the requirements for setting up special nodes, as shown in the attached figure. Figure 10 As shown, different shapes of steel reinforcement mesh can be freely formed according to design requirements, which can adapt to the connection requirements between the inner leaf wall 2 and the outer leaf wall 3 of different building structures.

[0068] The above description is merely a description of preferred embodiments of the present invention and is not intended to limit the scope of the present invention in any way. Any changes or modifications made by those skilled in the art based on the above disclosure shall fall within the protection scope of the claims.

Claims

1. A small connecting box for tying plain round steel bars in a self-insulating system, characterized in that, include: Box body (4), box cover (5) and height difference pad (6); several steel bar grooves (41) are formed inside the box body (4) and the box cover (5), and the several steel bar grooves (41) pass through the two end faces of the box body (4) and the box cover (5); one end of the two steel bars (1) is buried in the mortar joint of the inner leaf wall (2) and the outer leaf wall (3), and the other end of the two steel bars (1) is inserted into the two steel bar grooves (41). The box cover (5) matches and covers the box body (4) to form the connecting box body, so that the other end of the two steel bars (1) is connected through the connecting box body; the height difference pad (6) is embedded in the steel bar groove (41), so that the two steel bars (1) are horizontally tied between the connecting box body and the inner leaf wall (2) and between the connecting box body and the outer leaf wall (3).

2. The small connecting box for tying plain round steel bars in a self-insulating system as described in claim 1, characterized in that, The side of the steel bar groove (41) is formed with an extension groove (42), and the extension groove (42) and the steel bar groove (41) form an acute angle. The other end of the steel bar (1) is bent to form an end bend that matches the acute angle. The other end of the steel bar (1) is embedded in the steel bar groove (41), and the end bend of the steel bar (1) is embedded in the extension groove (42), so that the other end of the steel bar (1) is connected and fixed to the main body of the connecting box.

3. The small connecting box for tying plain round steel bars in a self-insulating system as described in claim 2, characterized in that, The main body of the connecting box is provided with two symmetrical steel bar grooves (41), and the number of extension grooves (42) is the same as the number of steel bar grooves (41); the length directions of the two steel bar grooves (41) are on the same straight line, forming a straight connecting box.

4. The small connecting box for tying plain round steel bars in a self-insulating system as described in claim 2, characterized in that, The main body of the connecting box is symmetrically provided with four steel bar grooves (41), and the number of extension grooves (42) is the same as the number of steel bar grooves (41); two of the steel bar grooves (41) are arranged along the length direction of the main body of the connecting box, and the other two steel bar grooves (41) are arranged along the width direction of the main body of the connecting box, forming a cross-shaped connecting box.

5. The small connecting box for tying plain round steel bars in a self-insulating system as described in any one of claims 2-4, characterized in that, The width of the groove of the steel bar (41) and the extension groove (42) is consistent with the diameter of the steel bar (1).

6. The small connecting box for tying plain round steel bars in a self-insulating system as described in claim 1, characterized in that, The elevation difference pad (6) is composed of one or more pads. One or more pads are embedded in the steel bar groove (41) and form a steel bar interlayer (44) in the steel bar groove (41). The other end of the steel bar (1) is inserted into the steel bar interlayer (44).

7. The small connecting box for tying plain round steel bars in a self-insulating system as described in claim 1 or 6, characterized in that, The height difference pad (6) has a through hole at one end away from the side wall of the box (4), and the steel bar groove (41) is provided with a limiting shaft (7) at one end away from the side wall of the box (4). The limiting shaft (7) passes through the height difference pad (6) through the through hole.

8. The small connecting box for tying plain round steel bars in a self-insulating system as described in claim 7, characterized in that, The limiting shaft (7) is fitted with a crash sleeve (71), and the end of the steel bar (1) can be perpendicularly abutted against the crash sleeve (71).

9. The small connecting box for tying plain round steel bars in a self-insulating system as described in claim 1, characterized in that, The outer wall of the box body (4) is provided with a number of box buckles (43) spaced apart, and the outer wall of the box cover (5) is provided with a number of cover buckles (51) spaced apart. The box buckles (43) and the cover buckles (51) are matched and fastened together.

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