JPH1181628A - Floor panel and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a floor panel facilely producible, having strong adhesive strength, securable of stable strength and light in weight. SOLUTION: A practically flat core material 3 of specific thickness positioned in a recessed part on a steel bottom plate 2 is intervened between a flat steel top plate 1 having almost a square circumference and the steel bottom plate 2 provided with the recessed part and having almost a square circumference. The circumferences of the top plate 1 and the bottom plate 2 are mechanically jointed together. At least either the upper surface or the lower surface of the core material 3 and either the top plate 1 or the bottom plate 2 facing the core material 3 surface are bonded together with an adhesive agent 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a floor panel comprising a steel plate top plate and a steel plate bottom plate with a core material interposed therebetween so as to be mechanically connected to the periphery thereof, and a method of manufacturing the floor panel. It is about.

[0002]

2. Description of the Related Art A conventional steel floor panel is formed by mechanically connecting the periphery of a steel plate top plate and a steel plate bottom plate and at the same time between the steel plate top plate and the steel plate bottom plate. Injection of lightweight concrete, or as shown in JP-A-3-28453 and JP-A-3-33361, a corrugated cross section was formed between a steel plate top plate and a steel plate bottom plate. It is known that a core piece made of steel sheet (that is, having a large number of grooves) is polymerized and bonded.

[0003]

In the case of a steel floor panel of the type in which lightweight concrete is poured into the interior, since the production process in the factory is a wet process, the process management becomes complicated and the floor panel becomes intricate. It is not easy to stabilize the quality of lightweight concrete to be filled into the interior, and it is difficult to secure stable strength as a floor panel. Furthermore, since the weight of the floor panel is as heavy as 8.0 to 9.0 kg per sheet,
There is a problem that the construction takes time and the load on the building is large.

A corrugated steel plate having a corrugated cross section (that is, having a large number of grooves) between a steel plate top plate and a steel plate bottom plate is polymerized and bonded.
Since the bonding is performed only linearly at the peaks and valleys of the corrugated cross section, the adhesive is easily peeled off, and it is difficult to secure the strength of the floor panel. The present invention has been invented in view of the problems of the above conventional example, panel manufacture is easy, the adhesive strength is strong, a stable strength can be secured,
Another object of the present invention is to provide a nonflammable, lightweight floor panel.

[0005]

In order to solve the above-mentioned problems, a floor panel according to the present invention has a flat top plate 1 made of a steel plate having a substantially rectangular periphery and a concave portion 2b having a substantially rectangular periphery. Between the steel-made bottom plate 2 and
A core material 3 having a predetermined thickness and a substantially flat plate shape is interposed in the concave portion 2b of the bottom plate 2 to mechanically couple the periphery of the top plate 1 and the bottom plate 2, and At least one of the upper surface or the lower surface of the material 3 and the top plate 1 or the bottom plate 2 facing the surface are formed of an adhesive 4
Characterized in that they are adhered to each other. By adopting such a configuration, it is not necessary to inject and cure the lightweight concrete as in the related art, and at least the top plate 1 made of a steel plate and the bottom plate 2 made of a steel plate are bonded by bonding the core material 3. It is only necessary to adhere to one side. Further, in bonding the core material 3 to the top plate 1 or the bottom plate 2,
The upper surface or the lower surface of the flat plate-shaped core material 3 interposed between the top plate 1 and the bottom plate 2 can be bonded to the top plate 1 or the bottom plate 2 in a planar manner, and a structure without adhesive separation can be achieved. Things.

Preferably, the upper surface of the core material 3 is adhered to the top plate 1 and the lower surface of the core material 3 is adhered to the bottom plate 2 with an adhesive 4. With such a configuration, when bonding the core material 3 to the top plate 1 and the bottom plate 2, the upper and lower surfaces of the flat core material 3 interposed between the top plate 1 and the bottom plate 2 are respectively set. The surface can be bonded to the top plate 1 and the bottom plate 2 in a planar manner, so that a structure without peeling off can be obtained.

Further, it is preferable that the bottom surface of the concave portion 2b of the bottom plate 2 made of a steel plate having the concave portion 2b and having a substantially square shape is curved inward. That is, normally, the bottom plate 2 is slightly curved outward, so that the core material 3 may not be sufficiently adhered at the center of the lower surface. However, the shape of the bottom surface of the bottom plate 2 is curved inward. With the shape, the center of the lower surface of the core material 3 is securely bonded to the center of the bottom surface of the bottom plate 2. Since a load is applied downward from the upper surface to the floor panel A, the central portion of the lower surface is the portion to which the tensile load is most applied. As described above, the center of the lower surface of the core material 3 is the central portion of the bottom surface of the bottom plate 2. In this way, the strength of the part where the tensile load is most applied increases.

The thickness of the core material 3 and the bonding of both surfaces are so fixed that the entire lower surface and the entire upper surface of the core material 3 are fixed to the bottom plate 2 and the top plate 1 via an adhesive 4 in a press-contact state. It is preferable that the total thickness of the four layers of the agent is equal to or slightly longer than the depth of the concave portion 2b of the bottom plate 2. In this manner, the thickness of the core material 3 and the adhesive on both sides are fixed so that the entire lower surface and the entire upper surface of the core material 3 are fixedly pressed to the bottom plate 2 and the top plate 1 via the adhesive 4 respectively. By making the total length of the layers the same length as or slightly longer than the depth of the recess 2b of the bottom plate 2, the strength of the floor panel A becomes strong. And the total length of the thickness of the core material 3 and the thickness of the adhesive layers on both sides is the same as the depth of the recess 2b of the bottom plate 2 even if the core material 3 has some undulations. Since the core material 3 is fixed in a press-contact state (that is, a state in which pressure is applied by a press) by making the core material 3
Can secure the flatness. In addition, the total length of the thickness of the core material 3 and the thickness of the adhesive layers on both sides is set to be equal to or slightly longer than the depth of the concave portion 2b of the bottom plate 2, so that the top plate 1 and the bottom plate 2 When the outer edge of the top plate 1 is folded back to the lower surface side of the outer edge of the bottom plate 2 when the periphery of the bottom plate 2 is mechanically joined, the mechanically joined portion tends to be inclined downward and downward. Does not protrude to the side.

Further, a means 30 for preventing the core member 3 from being displaced.
Is preferably provided on at least one of the top plate 1 and the bottom plate 2. With such a configuration, the core member 3 can be accurately positioned at the center position of the floor panel A. The adhesives 4 are two types of adhesives 4, a hot-melt type adhesive 4 a for temporary bonding and a urethane type adhesive 4 b for final bonding, and it is preferable to bond with the two types of adhesives 4. . With such a configuration, it is possible to maintain a pressurized state until the urethane-based adhesive for final bonding is hardened by the adhesive force of the hot-melt-based adhesive 4a for temporary bonding.

As the adhesive 4, a two-component urethane or epoxy adhesive 4 may be used.
It is preferable to use a liquid urethane-based or epoxy-based adhesive 4. Further, it is preferable that a space 9 as an adhesive reservoir is provided between the side end surface of the core material 3 and the two plates. With such a configuration, it is possible to eliminate a situation in which the protruding adhesive 4 goes out.

[0011] Further, the bonding portions of the urethane-based adhesive 4 for the actual bonding are provided at regular intervals on the entire bonding surface, and the hot-melt-based bonding agent 4 for the temporary bonding is spot-like at a plurality of locations on the bonding surface. Preferably, it is provided. With such a configuration, the application process of the adhesive 4 can be simplified. Further, a notch for drawing out an electric wire is provided on at least one side on the same side of the top plate 1 and the bottom plate 2, and a notch is provided on at least one side of the core material 3 at a position coinciding with the notch on the top plate 1.
Notch 33 for drawing out electric wires at least on one side of the floor panel
Is preferably provided. With such a configuration, it is possible to draw out wires such as electric wires and signal lines from below the floor panel A using the cutouts 33 provided in the floor panel A.

Further, the method for manufacturing a floor panel according to the present invention comprises a steel plate top plate 1 and a steel plate bottom plate 2.
And a method of manufacturing a floor panel in which a core material 3 interposed between the top plate 1 and the bottom plate 2 is bonded and laminated, wherein any one of the top plate 1 and the bottom plate 2 facing the core material 3 On either side, two types of adhesives 4 of a hot-melt type adhesive 4 for temporary bonding and a urethane type adhesive 4 for main bonding are applied, and the opposing surface of the opposing surface which is not the surface on which the adhesive 4 is applied. The core material 3 is coated with two types of adhesives 4, a hot-melt type adhesive 4 for temporary bonding and a urethane type adhesive 4 for final bonding, and then the top plate 1, the core material 3, and the bottom plate 2
And applying a pressure for a certain period of time to bond them. By adopting such a method, it is easy to simultaneously apply the adhesive 4 to the bonding surface between the top plate 1 and the core material 3 and to the bonding surface between the core material 3 and the bottom plate 2. The pressure for bonding the two bonding surfaces can be completed only once.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments shown in the accompanying drawings. 1, 2 and 3 show one embodiment of the present invention. Floor panel A is 24m thick
m and the outer dimensions are about 500 mm square. In this floor panel A, a substantially flat core material 3 having a predetermined thickness is interposed between a steel plate top plate 1 and a steel plate bottom plate 2 having a recess 2a. Are mechanically connected to each other. In the present invention, the entire upper surface of the substantially flat core material 3 having the predetermined plate thickness is covered with the top plate 1.
Then, the entire lower surface is bonded to the bottom plate 2.

The substantially flat core material 3 having a predetermined thickness has a substantially quadrangular shape in plan view. For example, a particle board is used. The particle board is generally used in building materials. Japanese Industrial Standard A5
13M that satisfies the standard of 908 particle board (Bending strength is 13.0 N / mm ² or more in both vertical and horizontal directions.
A urea-melamine co-condensation resin system or one having a performance equal to or higher than that of the urea-melamine co-condensation resin system or a urea-melamine co-condensation resin system having a bending strength of 18.0 N / mm ² in both the longitudinal and transverse directions. Or more, which has a thickness of about 22 mm to 23 mm and an outer dimension of about 450 mm square.

An example of an adhesive 4 for bonding the top plate 1 and the core material 3 and the bottom plate 2 and the core material 3 will be described below. In the present embodiment, the adhesive 4 for bonding the upper surface of the core material 3 to the top plate 1 and the lower surface to the bottom plate 2 is a two-component urethane-based or epoxy-based adhesive 4, or a one-component urethane. This is an example in which a system-based or epoxy-based adhesive 4 is used. Here, for example, as a two-component urethane-based adhesive, G by Sumitomo Bakelite is used.
A-700A, GA-732H can be adopted,
Further, EA-110-12 manufactured by Sumitomo Bakelite Co., Ltd. can be used as the two-part epoxy adhesive, and Bond Ku850 manufactured by Konishi Bond Co., Ltd. as the one-part urethane adhesive. Can be adopted. Table 1 below shows the specifications of the adhesive 4 exemplified above.

[0016]

[Table 1]

As described above, the top plate 1 and the bottom plate 2 are bonded in such a state that the entire upper surface of the substantially flat core material 3 having a predetermined thickness is adhered to the top plate 1 and the entire lower surface is adhered to the bottom plate 2. Are bent (clinched) and mechanically joined. In FIG. 1, reference numerals 1a and 2a denote bent portions, respectively, and both bent portions 1a and 2a are mechanically connected. When a plurality of floor panels A are laid in parallel as shown in FIG. 1, the bent sections 1a and 2a are arranged such that the vertical surfaces of the bent sections 1a abut against each other at the boundary between the floor panels A. I have. Then, the periphery of the top plate 1 and the bottom plate 2 are mechanically joined by the bending process by the clinch process as described above,
Preventing bending at the end of the surface of the top plate 1,
As shown in FIG. 1, when a plurality of floor panels A are laid in parallel, the upper surfaces can be flush with each other, and the floor panels A can be prevented from running over each other.

Table 2 below shows the strength test results of the floor panels A of Examples 1, 2, and 3 obtained as described above and the floor panel of the comparative example filled with lightweight concrete.
Shown in Here, in each example, the top plate 1 and the bottom plate 2 constituting the floor panel A are each made of a galvanized steel sheet having a thickness of 0.8 mm, the thickness of the floor panel A is 24 mm, and the outer dimensions are 500 mm square. .
Further, as the core material 3, 13M which satisfies the standard of A5908 particle board of Japanese Industrial Standard (bending strength is 13.0 N / mm ² or more in both vertical and horizontal directions,
A melamine co-condensation resin type or a particle board having a performance equal to or higher than that of the melamine co-condensation resin) having a thickness of 22 mm and external dimensions of 450 mm square was used. In Example 1, the one-part urethane adhesive shown in Table 1 was used as the adhesive 4 for bonding the upper surface of the core material 3 to the top plate 1 and the lower surface to the bottom plate 2. Example 2 used a two-part urethane adhesive shown in Table 1, and Example 3 used a two-part epoxy adhesive shown in Table 1.

On the other hand, in a conventional floor panel using lightweight concrete, a top plate 1 and a bottom plate 2 are each made of a galvanized steel sheet having a thickness of 0.8 mm, a floor panel A has a thickness of 24 mm, and an outer dimension of 500 mm. The corners are filled with lightweight concrete. In the test, a test was performed by applying a centralized load to the center of the floor panel A. In Table 2, the proportional limit refers to a limit in which a proportional relationship is established between the stress and the resulting strain as long as the stress does not exceed a certain value, and the relationship holds. The load at the time of sound generation refers to the load at which abnormal noise (such as crackling and crunching) starts to be generated. The load at the time of destruction indicates a load when a material or a structure breaks or breaks and cannot withstand an external force.

[0020]

[Table 2]

As can be seen from Table 2, the urethane-based and epoxy-based adhesives 4 have significantly higher strengths at the proportional limit, the load at the time of sound generation, and the load at the time of destruction than the conventional products. The amount of deflection at the center of the floor panel A under a heavy load of 300 kg satisfies the standard value of the Free Access Floor Industry Association. As shown in Table 1, Bond K manufactured by Konishi Bond Co., Ltd. was used as a one-part urethane adhesive.
When u850 is used, GA-700A or GA-732H manufactured by Sumitomo Bakelite Co., Ltd. is used as the two-component urethane adhesive, or Sumitomo Bakelite Co., Ltd. is used as the two-component epoxy adhesive. EA-110-1
In the case of using 2, since the viscosity of the one-pack type is higher and the curing time is shorter than that of the two-pack type, the two-pack type as exemplified in Table 1 is used in the production process of the present invention. Are considered suitable.

Next, other examples of the adhesive 4 for bonding the top plate 1 and the core material 3 and the bottom plate 2 and the core material 3 will be described below. In the present embodiment, the adhesive 4
In this case, two types of adhesives 4 are used, a hot-melt adhesive 4a for temporary bonding and a urethane-based adhesive 4b for final bonding. As shown in FIG. 4, the urethane-based adhesive 4b for final bonding is provided at regular intervals over the entire bonding surface.
The hot-melt adhesive 4a for temporary bonding is only provided at a plurality of spots on the bonding surface.

The urethane adhesive 4b for the final bonding is usually 6
Although the pressure-bonding state of about 7 hours is required at a minimum, the hot-melt adhesive 4a for temporary bonding is short, for example, 30 hours.
Utilizing the fact that the adhesive is hardened in about seconds and exhibits an adhesive strength, the adhesive strength of the hot melt adhesive 4a is reduced to the urethane adhesive 4a.
The pressing force until b hardens and exhibits the adhesive force is maintained. For this reason, if only the urethane-based adhesive 4b is used, the pressurized state by a press or the like must be maintained for a long time as described above.
If a pressure is applied by a press or the like only for a short time until a is hardened, only the stocking is performed thereafter, and a strong bonding state due to the hardening of the urethane-based adhesive 4b can be obtained during that time.

FIG. 5 shows an example of the application process of the adhesives 4a and 4b. A plurality of adhesive application nozzles 43 are arranged at intervals of, for example, 30 mm, and a part of these is applied to the hot melt adhesive 4a. And the remaining plural pieces are applied to the bottom surface of the concave portion 2a of the bottom plate 2 and the upper surface of the core material 3 for application of the urethane-based adhesive 4b, and the bottom plate 2, the core material 3, and the top plate 1 are stacked in this order. The above-mentioned bonding is performed by applying pressure. If the adhesive application nozzle 43 is to be moved, the hot melt adhesive 4
One nozzle 43 may be used for both the application of a and the application of the urethane adhesive 4b. The adhesive 4
The application patterns of the hot melt adhesives 4a and 4b are not limited to those shown in FIG. 4. The hot melt adhesive 4a is scattered on the adhesive surface (the four corners and the center) so that the urethane adhesive 4b covers almost the entire adhesive surface. Is preferable). Although the amount of the adhesives 4a and 4b used depends on the size of the floor panel A, the urethane-based adhesive 4b is used.
Is about 100 g / sheet, the hot melt adhesive 4
a is about 8 g / sheet.

The particle board used as the core material 3 is 13M (bending strength is 13.0 N / m in both longitudinal and transverse directions) which satisfies the Japanese Industrial Standard A5908 particle board which is generally used for building materials.
In m ² or more, those urea-melamine co-condensation resin or its performance is equivalent or superior) or 18M (bending strength of 18.0N / mm ² in both the longitudinal and transverse directions, urea-melamine co-condensation resin Or a material having the same or higher performance), a thickness of about 22 mm to 23 mm, and an outer dimension of about 450 mm square. As the hot-melt adhesive 4a, a strongly adhesive type (aver grip PS-948 or PS-948 manufactured by ACI Japan Limited) having a time until hardening is about 30 seconds is used.
712) and a two-component type (GA-700A manufactured by Sumitomo Bakelite Co., Ltd.) or a one-component type (KU-850 manufactured by Konishi Co., Ltd.) as the urethane-based adhesive 4b with a thickness of 24 mm. In order to manufacture the floor panel A having the outer dimensions of about 500 mm square, the adhesives 4a and 4b are applied to the bottom plate 2 and the core material 3 flowing on the conveyor using an adhesive applying machine as shown in FIG. And 4 to 5 kg / cm ² by a 10 t press.
Is applied to the entire surface of the floor panel A, and the adhesive is applied for about 2 seconds, the pressing time by the press is about 10 seconds, and the pressing time is 15 seconds per sheet including the handling time. Although it took only about a second, the floor panel A after the time required for curing the urethane-based adhesive 4b has elapsed was able to obtain a high-strength and light weight of about 7.4 kg. .

In the above, the concave portion 2 of the bottom plate 2
Although the example in which the adhesives 4a and 4b are applied to the bottom of the core material 3 and the upper surface of the core material 3 has been described, the adhesive may be applied to the lower surface of the top plate 2 and the lower surface of the core material 3 (in this case, the top plate 2 is applied upside down), in any case, by preparing two adhesive applicators, the adhesives 4a and 4b can be simultaneously and easily applied to the two adhesive surfaces.

Further, adhesives 4 a and 4 b may be applied to the lower surface of the top plate 2, the bottom surface of the concave portion 2 a of the bottom plate 2, and the upper and lower surfaces of the core material 3. In this case, for example, the top plate 2 is
Adhesives 4a and 4b are applied to the lower surface (the surface located on the upper side because it is turned upside down), and adhesives 4a and 4b are applied to one surface of the core material 3 to bond the core material 3 upside down. The surface on which the agents 4a and 4b are applied is bonded to the adhesive 4 of the top plate 1.
a, 4b are applied to the surface on which the core material 3 is applied, and the adhesives 4a, 4b are applied to the upper surface, which is the other surface of the core material 3, and the adhesives 4a, 4b are applied to the bottom of the concave portion 2a of the bottom plate 2. Then, the bottom plate 2 is turned upside down and the core material 3
The surface of the core material 3 on which the adhesives 4a and 4b are applied and the bottom surface of the concave portion 2a of the bottom plate 2 on which the adhesives 4a and 4b are applied may be overlapped and pressed for bonding. is there.

A space 9 as shown in FIGS. 1, 6, and 7 is provided between the peripheral edge where the top plate 1 and the bottom plate 2 are mechanically connected and the side end surface of the core material 3.
Is caused. The space 9 functions as an adhesive pool in which the adhesive 4 protruding from the bonding surface at the time of the above-mentioned pressurization accumulates, so that the adhesive 4 protrudes outside through a mechanical connection portion with the top plate 1 and the bottom plate 2. It is to prevent that. It is preferable that the space 9 has a width of about 5 mm from the viewpoint of securing the strength of the peripheral portion of the floor panel A. The mechanical coupling between the top plate 1 and the bottom plate 2 is not limited to that of FIG.
They may be connected as shown in FIG.

In any of the above embodiments, the total length of the thickness of the core material 3 and the thickness of the adhesive layers on both sides is set to be equal to or slightly longer than the depth of the concave portion 2b of the bottom plate 2. Thus, the bottom surface of the concave portion 2a of the bottom plate 2 and the bottom surface of the top plate 1 have the entire lower surface of the core material 3 and the entire upper surface thereof in a state where the core material 3 is disposed in the concave portion 2b of the bottom plate 2. Each is fixed in a press-contact state via an adhesive 4. In this case, if the thickness of the core material 3 is the same as or slightly longer than the depth of the concave portion 2 b of the bottom plate 2, considering the thickness of the adhesive 4, the thickness of the core material 3 and the adhesive The total length of the thickness can be made slightly longer than the depth of the concave portion 2b of the bottom plate 2, and the entire surface of the lower surface of the core material 3 and the entire surface of the upper surface of the core material 3 are always bonded by pressing under pressure. Can be fixed to the bottom plate 2 and the top plate 1 via an adhesive 4 in a press-contact state.

Here, the total length of the thickness of the core material 3 and the thickness of the adhesive layers on both sides is equal to the thickness of the recess 2 of the bottom plate 2.
9B, when the upper and lower surfaces of the core material 3 are bonded to the bottom plate 2 and the top plate 1 with the adhesive 4 as in the comparative example shown in FIG. Floor panel A
There is a possibility that an unfavorable situation may occur in the flat surface of the upper surface of the above, but in the present invention, as described above,
The thickness of the core material 3 and the thickness of the adhesive layers on both surfaces are fixed so that the entire lower surface and the entire upper surface of the core material 3 are fixed to the bottom plate 2 and the top plate 1 via an adhesive 4 by pressing. The total length is the concave portion 2b of the bottom plate 2.
9A, the lower surface and the upper surface of the core material 3 can always be bonded to the bottom plate 2 and the top plate 1 over the entire surface, as shown in FIG. As shown in the comparative example of FIG. 9B, an unbonded portion is not formed, and the flatness of the upper surface of the floor panel A (that is, the top plate 1) can be secured by utilizing the flatness of the core material 3. It is.

After the bonding step of bonding the upper and lower surfaces of the core material 3 to the bottom plate 2 and the top plate 1 with the adhesive 4, the outer end of the top plate 1 is connected to the lower surface of the outer end of the bottom plate 2. The floor panel A is formed by performing a so-called hemming step of folding back into a mechanical connection to form the floor panel A. In the case of the comparative example shown in FIG. 9B, the mechanical connection portion is formed as shown in FIG. 9D. When the surface finishing material such as a tile carpet is laid on the upper surface of the floor panel A at the time of construction, the surface finishing material is lifted upward by an obliquely upwardly projecting portion of the mechanical joint, The surface finish deteriorates, and the walking performance deteriorates. However, in the present invention, as described above, the entire lower surface and the entire upper surface of the core material 3 are fixed to the bottom plate 2 and the top plate 1 via the adhesive 4 in a pressure-contact state. 9 is equal to or slightly longer than the depth of the concave portion 2b of the bottom plate 2, so that the thickness of FIG.
After the bonding step (a), a so-called hemming step of folding the outer end of the top plate 1 to the lower surface side of the outer end of the bottom plate 2 is performed to perform mechanical connection. 9), the surface is slightly inclined downward, and when a surface finishing material such as a tile carpet is laid on the upper surface of the floor panel A at the time of construction, the surface finishing material rises upward as in the comparative example of FIG. There is no such thing as being lifted.

Even if the core material 3 has some undulations, the entire bottom surface and the entire top surface of the core material 3 are respectively bonded to the bottom plate 2 and the top plate 1 via the adhesive 4.
Since the total length of the thickness of the core material 3 and the thickness of the adhesive layers on both sides is set to be equal to or slightly longer than the depth of the concave portion 2b of the bottom plate 2,
At the time of bonding, as shown in FIG. 9A, the core material 3 is pressed from the bottom plate 2 side and the top plate 1 side and fixed in a press-contact state, whereby the flatness of the floor panel A to be formed is secured. Things.

Here, in the present invention, a substantially flat core material 3 is interposed between the top plate 1 and the bottom plate 2 having the concave portion 2b, so that the lower surface and the upper surface of the core material 3 are entirely covered with the bottom plate. When bonding the core material 3 to the top plate 1, as shown in FIGS.
It is preferable to provide it on at least one of the bottom plates 2.

That is, the core material 3 makes the fitting of the bottom plate 2 made of steel plate into the recess 2b smooth, absorbs the difference in expansion and contraction due to the difference in material, absorbs the manufacturing error, and furthermore, as described above, the adhesive It is necessary to make the core material 3 a little smaller than the concave portion 2b and to form a gap (space 9) between the inner peripheral surface of the concave portion 2b and the outer peripheral surface of the core material 3 for reasons such as forming a space that becomes a pool. However, if the center of the core material 3 does not coincide with the center of the floor panel A to be formed, the gap between the outer peripheral surface of the core material 3 and the inner peripheral surface of the concave portion 2b is not uniform, and Although the panel A cannot have the predetermined strength, as described above, by providing the misalignment prevention means 30 for the core material 3 on at least one of the top plate 1 and the bottom plate 2,
At the time of bonding, the core material 3 can be positioned at an accurate position. Then, the outer peripheral surface of the core material 3 and the concave portion 2
Since the gap between the inner peripheral surface of the floor panel A and the inner peripheral surface of the floor panel A becomes uniform, the gap becomes uniform on the four sides of the floor panel A to be formed, and the four corners are supported by the supporting legs 7 as shown in FIG. The portion for receiving the floor panel A of No. 7 can be made small, and the cost can be reduced. In other words, when the floor panel A is received by the support leg 7, it is necessary to support the bonded portion of the core material 1 with the support leg 7 in order to secure the supporting strength. However, the gap is made uniform on the four sides of the floor panel A. Thus, even if the portion of the support leg 7 that receives the floor panel A is made small, it can be reliably supported at the four corners of the floor panel A.

In the embodiment shown in FIGS. 7, 8 to 17, a part of the top plate 1 is bent downward to form a bent part 31 (for example, the bent part 31 is shown in FIG. 20). As shown in FIG. 21, the projection 31 has a shape of a truncated cone or a truncated quadrangular pyramid as shown in FIG. 21). A concave portion 32 into which the portion 31 fits is provided, and the concave portion 32 of the core material 3 is fitted into the protruding portion 31 of the top plate 1 so that the core material 3 is positioned at a predetermined position on the top plate 1.
Can be positioned.

In this case, as shown in FIG.
Is bent at a right angle to the top plate 1 to form a vertical piece 41, and the top plate 1 is turned upside down so that the vertical piece 41 projects upward, and adhered to the top plate 1. In this state, the core material 3 coated with the adhesive 4 on the upper surface (or both upper and lower surfaces) is placed on the top plate 1 and the recess 32 is fitted into the protruding portion 31 and positioned. Next, an adhesive is applied to the bottom of the concave portion 2b, or the bottom plate 2 on which the adhesive is not applied is placed on the core material 3 in a state where the bottom plate 2 is turned upside down. The bottom plate 2 and the top plate 1 are aligned with the protruding base.
The core member 3 and the core member 3 are aligned, and in this state, pressing is performed to press the entire lower surface and the entire upper surface of the core material 3 against the bottom plate 2 and the top plate 1 via the adhesive 4. Then, the vertical piece 41 is folded back so as to overlap the outer peripheral end of the bottom plate 2 to form the floor panel A.

The bottom plate 2 is provided with a stacking projection 39 at a position facing the projection 31 so that a plurality of floor panels A can be stacked and stored or transported when the floor panels A are stacked or transported. Of the floor panels A are fitted with the stacking projection 39 and the recess on the upper surface side of the projection 31 to prevent lateral displacement. FIG.
2. In the embodiment shown in FIG. 16, the protrusions 31 are formed at four places of the top plate 1, and the four protrusions 31 have a uniform positional relationship about the center of the top plate 1. It is arranged in such a way. Of course, the present invention is not limited to the above-described embodiment.
It may be arranged at a position to be rotated by 80 °.

The dimensional relationship between the protruding portion 31 and the recess 32 is as follows: the width of the protruding base of the protruding portion 31 shown in FIG. When the groove width of the recess 32 is X and the groove depth of the recess 32 is Y, x ≦ X, y
.Ltoreq.Y, so that the protruding portion 31 of the top plate 1 fits securely into the recess 32 of the core material 3, so that the top plate 1 and the core material 3 The core material 3 and the top plate 1 can be securely adhered to each other, and the flatness can be secured, and the strength can be secured.

In the above embodiment, the example in which the means 30 for preventing displacement of the core material 3 is provided on the top plate 1 has been described, but it may be provided on the bottom plate 2 side. It may be provided on both the plate 1 and the bottom plate 2. As the floor panel A formed as described above, a U-shaped notch 33 is formed at the outer end as shown in FIG.
There are some which do not have the notch 33 as shown in FIG. In order to form the notch 33, notches 33a and 33b for drawing out electric wires are provided on at least one of the same sides of the top plate 1 and the bottom plate 2 as shown in FIGS. The notch 33c is provided at a position corresponding to the notch 33a of the top plate 1 on at least one side of the material 3, and the notch 33 for drawing out the electric wire is formed on at least one side of the floor panel A. Notch 33
Is formed on the inner peripheral portion of the notch 33.
A lid 35 as shown in FIG. 18 is removably mounted on the step piece 34. Lid 3
5 is provided with a locking leg 36 hanging therefrom. When the lid 35 is placed on the step piece 34 from above, the locking claw 3 at the tip of the locking leg 36 is provided.
6 a is adapted to be locked on the lower surface side of the step projection 34. In order to release the locking of the locking claw 36a, a jig such as a screwdriver is inserted from an operation hole 35a formed in the lid 35 and the locking leg 36 is pressed to lock the locking claw 36a. The lid 35 can be released and the lid 35 can be removed.
The lid 35 is provided with a removable portion 37, and the removable portion 3
The periphery of 7 is a knockout groove 38 such as a thin wall.
Therefore, by removing and removing the removable portion 37,
The wiring can be drawn out from this part. The removable portion 37 may be a door that can be freely opened and closed. Further, instead of the lid 35, a floor outlet may be fitted into the notch 33 and attached to the step projection 34.

Next, another embodiment of the present invention will be described with reference to FIGS. In the present embodiment,
In the floor panel A having the configuration shown in each of the above embodiments, a plurality of bolts 14 are passed through the top plate 1 and the bottom plate 2 and fixed with the nuts 15 in order to further enhance the strength of the core material 3 made of the particle board. This is an example. A plurality of recesses 16 are provided on the upper surface of the top plate 1 made of a steel plate so that the head 14a of the bolt 14 does not protrude above the upper surface of the top plate 1. A through hole 17 for inserting the bolt 14 is provided. Core material 3 has top plate 1
A predetermined number of through-holes 18 are provided at predetermined positions so as to coincide with and communicate with the through-holes 17 provided in the top plate 1 when the core material 3 and the core material 3 are bonded. As shown in FIG. 23, a perforated nut 19 is embedded in the through hole 18 of the core material 3 to help prevent the bolt from falling off.
A predetermined number of through-holes 20 are provided in the bottom plate 2 at predetermined positions so as to coincide with the through-holes 18 of the core material 3 and to communicate with each other when the core material 3 is bonded to the bottom plate 2. Then, the bolt 14 is inserted through the through hole 17 provided in the top plate 1, passed through the onion nut 19 embedded in the through hole 18 provided in the core material 3, and penetrated through the through hole 20 of the bottom plate 2, and The top plate 1, the core material 3, and the bottom plate 2 are fixed by screwing 15. Further, also in this embodiment, the bent portion 1 around the top plate 1 and the bottom plate 2 is formed.
a and 2a are mechanically connected.

With the above structure, the upper and lower surfaces of the core material 3 shown in each of the above-described embodiments are respectively
And a floor panel A having a strength even higher than the strength of the floor panel A whose periphery is mechanically bonded to the bottom panel 2. Next, still another embodiment of the present invention will be described with reference to FIGS. The floor panel A of the embodiment shown in FIGS. 24 and 25 is an example for further strengthening the strength of the core material 3 made of particle board, similarly to the floor panel A of the embodiment shown in FIGS. .
That is, in the present embodiment, a plurality of bolt-like protrusions 21 are provided on the surface of the top plate 1 that is in contact with the core material 3.
Are provided, and through holes 18 and 20 are provided in the core material 3 and the bottom plate 2 at positions corresponding to the respective protrusions 21 so that the projections 21 penetrate, and the upper surface of the core material 3 and the top plate 1 are bonded to each other. At the same time, the lower surface of the core material 3 and the bottom plate 2 are bonded together.
The projection 21 provided on the top plate 1 is inserted into the through hole 18 of the core material 3 and the through hole 20 of the bottom plate 2, and a nut 15 is screwed into a lower end of the projection 21 to thereby fix the top plate 1 and the core material 3. , The bottom plate 2 is fixed. Also in this embodiment, the bent portions 1a and 2a around the top plate 1 and the bottom plate 2 are mechanically connected.

With the above structure, the upper and lower surfaces of the core material 3 shown in each of the above-described embodiments are respectively
And a floor panel A having a strength even higher than the strength of the floor panel A whose periphery is mechanically bonded to the bottom panel 2. By the way, in any of the embodiments described above, the bottom plate 2 made of a steel plate has a box shape having a bottom surface and side surfaces. Then, the core material 3 is put in the box-shaped steel plate bottom plate 2, and the lower surface of the core material 3 is bonded to the bottom surface of the steel plate bottom plate 2 with the adhesive 4. In each case, in each of the above-described embodiments, the shape of the bottom surface of the bottom plate 2 is curved inward (that is, upward). Here, the width of the bottom surface of the bottom plate 2 is, for example, 500 mm.
In this case, the bottom surface is curved inward (that is, upward) so that the center of the bottom surface of the bottom plate 2 is higher than the end of the bottom surface by about 1 to 2 mm.

The reason why the shape of the bottom surface of the bottom plate 2 is curved inward as described above is as follows. That is, normally, the bottom plate 2 is slightly curved outward, so that the center of the lower surface of the core material 3 may not be sufficiently bonded, but the bottom surface of the bottom plate 2 is curved inward. By adopting the shape, the center of the lower surface of the core material 3 is securely bonded to the center of the bottom surface of the bottom plate 2. Since a load is applied downward from the upper surface to the floor panel A, the central portion of the lower surface is the portion to which the tensile load is most applied. As described above, the center of the lower surface of the core material 3 is the central portion of the bottom surface of the bottom plate 2. In this way, the strength of the part where the tensile load is most applied increases.

Although the core member 3 is constituted by a particle board in the above-described embodiment, in any of the above embodiments, FIG.
As shown in FIG. 7, the intermediate portion 3c may be made of a material that is coarser than the upper and lower layer portions 3a and 3b. For example,
A dense layer of only melamine resin thinner than the intermediate portion 3c was formed on the upper and lower surfaces of the rough intermediate portion 3c obtained by binding and molding a piece of wood using a melamine resin as a binder, or pumice was formed by binding a phenol resin as a binder. On the upper and lower surface portions of the coarse intermediate portion 3c, a dense layer made of only a phenol resin thinner than the intermediate portion 3c is formed.

With such a configuration, the weight can be reduced and the weight can be reduced.
The weight of the core material 3 having a thickness of 24 mm is reduced from 7 kg to 4 kg.
The weight can be reduced. Further, the surface of the core material 3 is dense and has little irregularity in the case of resin, and there is a problem that the bonding strength is not increased because the bonding surface is small. Therefore, the surface of the core material 3 is roughened with a sander to make the surface uneven, thereby increasing the adhesive strength between the upper surface of the core material 3 and the top plate 1 and between the lower surface of the core material 3 and the bottom plate 2.

In any of the above embodiments,
The top plate 1 and the bottom plate 2 made of a steel plate may be galvanized on the surface. Since the top plate 1 and the bottom plate 2 are plated with zinc as described above, the surface of the top plate 1 and the bottom plate 2 not only have a rust-preventing effect, but also the surface irregularities can be increased as compared with the case of painting or the like. 3 can increase the bonding strength.

In each of the above embodiments, the upper and lower surfaces of the core material 3 are bonded to the top plate 1 and the bottom plate 2 with the adhesive 4, respectively, but either the upper surface or the lower surface of the core material 3 is used. Only one of the top plate 1 and the bottom plate 2 may be bonded with the adhesive 4.

[0048]

According to the first aspect of the present invention, as described above, a flat top plate made of a steel plate having a substantially square periphery and a substantially square periphery having a recess are provided. Between the bottom plate made of a steel plate and a substantially flat plate-shaped core material having a predetermined thickness positioned in the recess of the bottom plate, and mechanically surrounding the top plate and the bottom plate. At the same time, the top plate or the bottom plate opposed to at least one of the upper surface or the lower surface of the core material and the top plate or the bottom plate facing the surface are bonded by an adhesive. -It is only necessary to adhere to the bottom plate made of steel plate, and it is easier to manufacture than the one that is manufactured by pouring the conventional lightweight concrete. In bonding the top plate to the bottom plate, the upper or lower surface of the flat core material interposed between the top plate and the bottom plate can be bonded to the top plate or the bottom plate in a planar manner, It is possible to provide a floor panel having non-combustibility because it has a structure with no adhesion and peeling and has high strength, and the top plate and the bottom plate are made of steel plate.

According to the second aspect of the invention, in addition to the effects of the first aspect, the upper surface of the core material is bonded to the top plate, and the lower surface of the core material is bonded to the bottom plate. In bonding the core material to the top plate and the bottom plate, the upper and lower surfaces of the flat core material interposed between the top plate and the bottom plate are respectively planarized with the top plate and the bottom plate. It can be bonded to a plate and can have a structure without peeling.

According to the third aspect of the present invention, in addition to the effects of the first or second aspect of the present invention, the concave portion of the bottom plate made of a steel plate having a concave portion and having a substantially square periphery. The bottom surface of the core material is curved inward, so that the center of the lower surface of the core material can be securely bonded to the center of the bottom plate of the bottom plate. As a result, the highest tensile load is applied when a load is applied from above. It is possible to achieve high strength without adhesive peeling or the like at the center of the lower surface of the floor panel which is the portion.

According to the fourth aspect of the present invention, in addition to the effects of the first or second aspect of the present invention, the entire lower surface and the entire upper surface of the core material are respectively bonded with an adhesive. The total length of the thickness of the core material and the thickness of the adhesive layers on both sides is made equal to or slightly longer than the depth of the recess of the bottom plate so that the bottom plate and the top plate are fixed to the bottom plate and the top plate in pressure contact. In addition, the strength of the floor panel is strengthened, and the flatness of the core material ensures the flatness of the top plate. Even if the core material has some undulations, the thickness of the core material and the adhesion on both sides The total length of the thickness of the agent layer is equal to or slightly longer than the depth of the concave portion of the bottom plate, and is fixed in a press-contact state, so that the flatness of the core material can be ensured. Thickness and contact on both sides When the total length of the thickness of the agent layer is equal to or slightly longer than the depth of the concave portion of the bottom plate, when the periphery of the top plate and the bottom plate are mechanically joined, the outer edge of the top plate is If the part is folded back to the lower surface side of the outer end of the bottom plate, the mechanical connection tends to slope downward and does not protrude to the surface finish side, so the surface finish is applied to the floor panel surface. When laying, the surface finishing material is partially pushed upwards, and the finish of the floor surface is deteriorated,
The walking ability does not deteriorate.

According to the fifth aspect of the present invention, in addition to the effects of the first to fourth aspects, the core member is accurately positioned at the center of the floor panel. The gap between the four sides of the floor panel where there is no core material becomes uniform, and the support legs support the four corners of the floor panel. Even if the part receiving the panel is small, it can be securely supported at the four corners of the floor panel, and can be easily positioned at the time of bonding at the time of manufacturing, so that manufacturing time can be shortened and cost can be reduced. is there.

According to the sixth aspect of the present invention, in addition to the effects of the first to fifth aspects of the present invention, the adhesive is a hot-melt adhesive for temporary bonding. The two types of urethane-based adhesives for the final bonding are used. Since the two types of adhesives are used for the bonding, the pressing time by the press is short enough to cure the hot-melt-based adhesive. In addition, a sufficient adhesive force can be obtained after the urethane-based adhesive is cured, which is excellent in both cost and adhesive strength.

According to a seventh aspect of the present invention, in addition to the effects of the first aspect, the adhesive is a two-part urethane or epoxy adhesive. Since it is an adhesive, the flat core material can be firmly bonded to the top plate or the bottom plate in a planar manner. Further, in the invention according to claim 8, in addition to the effect of the invention according to any one of claims 1 to 5, the adhesive is a one-part urethane-based or epoxy-based adhesive. Therefore, the flat core material can be firmly adhered to the top plate or the bottom plate in a planar manner.

According to the ninth aspect of the present invention, in addition to the effects of the first aspect of the present invention, an adhesive is provided between the side end face of the core material and the two plates. Since the space as the agent pool is provided, it is possible to obtain an adhesive that does not protrude to the outside,
This makes it possible to respond to dimensional changes of the core material and absorb walking sounds.

According to the tenth aspect of the present invention,
In addition to the effect of the invention according to claim 6, the bonding portion made of the urethane-based adhesive for the final bonding is provided at regular intervals on the entire bonding surface, and the hot-melt adhesive for the temporary bonding is formed on the bonding surface. Since a plurality of spots are provided in a spot manner, the equipment for applying the adhesive can be simplified.

In the invention according to claim 11,
In addition to the effects of the invention according to any one of claims 1 to 10, in addition to providing a notch for drawing out an electric wire on at least one side on the same side of the top plate and the bottom plate, the top plate is formed on at least one side of the core material. A notch is provided at a location that matches the notch of the floor panel, and a cutout portion for drawing out electric wires is provided on at least one side of the floor panel. Etc. can be drawn out,
In addition, by providing notches in the core material at locations that match the notches on the top plate, the core material can be fitted around the notch, despite the notch, providing strength around the notch. Can be secured.

According to the twelfth aspect of the present invention,
A method of manufacturing a floor panel in which a steel plate top plate, a steel plate bottom plate, and a core material interposed between the top plate and the bottom plate are bonded and laminated, wherein the core material in the top plate and the bottom plate is provided. And two types of adhesives, a hot-melt type adhesive for temporary bonding and a urethane type adhesive for final bonding, are applied to one of the opposing surfaces, and the other of the opposing surfaces is not the adhesive-applied surface. Two types of adhesives, a hot-melt adhesive for temporary bonding and a urethane-based adhesive for final bonding, are applied to the core material facing the opposite surface, and then the top plate, the core material, and the bottom plate are overlaid for a certain period of time. Since pressure is applied for bonding, it is possible to simultaneously apply the adhesive to the bonding surface between the top plate and the core material and the bonding surface between the core material and the bottom plate. On it, which pressurized for adhesion of the two adhesive surfaces can be finished in one, one in which it is possible to shorten the time required for simplification and manufacturing of the manufacturing process.

[Brief description of the drawings]

FIG. 1 is a sectional view of the present invention.

FIG. 2 is an exploded perspective view of the same.

FIG. 3 is an explanatory view of a state in which the floor panels are arranged side by side.

FIG. 4 is an exploded perspective view of another embodiment of the present invention.

FIG. 5 is a schematic perspective view of an adhesive application facility in manufacturing the same.

FIG. 6 is a cross-sectional view of the floor panel.

FIG. 7 is a sectional view of another embodiment of the present invention.

FIG. 8 is an exploded cross-sectional view of the same before bonding.

9 (a) and 9 (b) are explanatory views showing the state of adhesion between the present invention and a comparative example, and FIGS. 9 (c) and 9 (d) show the outer ends of the top plate folded back to the outer ends of the bottom plate. It is explanatory drawing of the state which is mechanically connected.

FIG. 10 is a bottom view of an example of the floor panel.

FIG. 11 shows an example of a bottom plate used in the above.
(A) is a plan view, (b) is a front view, (c)
Is a side view.

FIG. 12 shows an example of a top plate used in the above.
(A) is a plan view, (b) is a front view, (c)
Is a side view.

FIG. 13 shows an example of a core material used in the above, and (a)
Is a plan view, (b) is a front view, and (c) is a side view.

FIG. 14 is a bottom view of another example of the same floor panel.

FIG. 15 shows another example of the bottom plate used in the above.
(A) is a plan view, (b) is a front view, (c)
Is a side view.

FIG. 16 shows an example of a top plate used in the above.
(A) is a plan view and (b) is a front view.

FIG. 17 shows an example of a core material used in the above, and (a)
Is a plan view, (b) is a front view, and (c) is a side view.

18 (a) is a perspective view, FIG. 18 (b) is a plan view, FIG. 18 (c) is a front view,
(D) is a side view.

FIGS. 19A and 19B illustrate a state in which four corners of the floor panel are supported by support legs, where FIG. 19A is a plan view and FIG. 19B is a cross-sectional view.

FIG. 20 shows an example of the above-mentioned bent portion, wherein (a) is a plan view and (b) is a cross-sectional view.

21A and 21B show another example of the above-described protruding portion, in which FIG. 21A is a plan view and FIG. 21B is a cross-sectional view.

FIG. 22 is a sectional view of another embodiment of the present invention.

FIG. 23 is an enlarged sectional view of a main part of the above.

FIG. 24 is a sectional view of still another embodiment of the present invention.

FIG. 25 is an enlarged sectional view of a main part of the above.

FIG. 26 is a cross-sectional view of another embodiment of the core material used in the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Top plate 2 Bottom plate 3 Core material 4 Adhesive A Floor panel

Continued on the front page (72) Inventor Yoji Endo 1048 Kazuma Kadoma, Kadoma City, Osaka Inside Matsushita Electric Works, Ltd.

Claims (12)

[Claims] 1. A flat plate having a substantially square-shaped periphery and a steel-made top plate and a bottom plate made of a steel plate having a substantially square-shaped periphery and located in the concave portion of the bottom plate. A core material having a substantially flat plate shape with a predetermined thickness is interposed, and the periphery of the top plate and the bottom plate is mechanically coupled, and at least one of the upper surface or the lower surface of the core material and A floor panel, wherein the top plate or the bottom plate facing a surface is bonded with an adhesive. 2. The floor panel according to claim 1, wherein an upper surface of the core material is bonded to the top plate, and a lower surface of the core material is bonded to the bottom plate with an adhesive. 3. The floor panel according to claim 1, wherein the bottom surface of the concave portion of the bottom plate made of a steel plate having a concave portion and having a substantially square shape is curved inward. 4. The thickness of the core material and the thickness of the adhesive layers on both sides of the core material so that the entire lower surface and the entire upper surface of the core material are fixed to the bottom plate and the top plate via an adhesive. 3. The floor panel according to claim 1, wherein the total length is equal to or slightly longer than the depth of the recess of the bottom plate. 5. The floor panel according to claim 1, wherein a means for preventing the core material from being displaced is provided on at least one of the top plate and the bottom plate. 6. An adhesive comprising two kinds of adhesives, a hot melt adhesive for temporary bonding and a urethane adhesive for final bonding, wherein the two kinds of adhesives are used for bonding. The floor panel according to any one of claims 1 to 5. 7. The floor panel according to claim 1, wherein the adhesive is a two-part urethane-based or epoxy-based adhesive. 8. The floor panel according to claim 1, wherein the adhesive is a one-part urethane or epoxy adhesive. 9. The floor panel according to claim 1, wherein a space as an adhesive reservoir is provided between the side end surface of the core material and the two plates. 10. Adhesive portions made of a urethane-based adhesive for permanent bonding are provided at regular intervals over the entire bonding surface, and hot-melt adhesives for temporary bonding are provided in spots at a plurality of locations on the bonding surface. The floor panel according to claim 6, wherein the floor panel is provided. 11. A notch for drawing out an electric wire is provided on at least one side on the same side of the top plate and the bottom plate, and a notch is provided on at least one side of the core material so as to coincide with the notch on the top plate. The floor panel according to any one of claims 1 to 10, wherein a cutout portion for drawing out an electric wire is provided on one side. 12. A method of manufacturing a floor panel comprising a steel plate top plate, a steel plate bottom plate, and a core material interposed and laminated between the top plate and the bottom plate. Applying two types of adhesives, a hot-melt adhesive for temporary bonding and a urethane-based adhesive for final bonding, to one of the opposing surfaces of the plate and the core material, Apply two types of adhesives, a hot-melt adhesive for temporary bonding and a urethane adhesive for final bonding, to the core material facing the opposing surface that is not the adhesive application surface, and then apply the top plate, core material, and bottom A method for manufacturing a floor panel, comprising applying a pressure for a certain period of time to overlap with a tray.