JP2009102922A - Plain roof tile and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plain roof tile not only reduced in weight but also improved in wind resisting performance by nailing a flow direction middle section of an underlap and prevented from cracking of the underlap due to impact in nailing. <P>SOLUTION: The plain roof tile 1 made of pottery comprises an underlap 3 on one side of a roof tile body 2; an overlap 4 on the other side of the roof tile body 2; roof tile body support legs 11 formed on the back face of the underlap 3 to project downward and to ground on a sheathing roof surface 20; an underlap support leg 12 formed on the back face of the underlap 3 to project downward and to ground on the sheathing roof surface 20; and an underlap nail hole 13 formed in the flow direction middle part of the underlap 3 to nail the sheathing roof surface 20 or a stiffener 23. The plain roof tile 1 is dry-formed, and after applying glaze, placed directly in a horizontal attitude on a hearth roller of a roller hearth kiln and baked. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a flat roof tile and a manufacturing method thereof.

  In order to reduce the weight of the tile, it is necessary to reduce the thickness of each part including the tile body. However, when the wall thickness of the roof tile or the like is reduced, the bending strength and the like are lowered, and problems such as tread cracks occur. In order to compensate for this decrease in bending strength, it is considered that protrusions (leg walls, ribs, back feet) on the back surface of the tile as described in Patent Documents 1 to 3 are effective.

Patent Document 1 describes a corrugated roof tile compression-molded with a synthetic resin blended with glass fiber, with a rectangular frame-shaped leg wall and a grid-shaped leg wall between them protruding from the back of the tile plate. Has been.
In Patent Document 2, in a roof material manufactured by injection molding, casting, or the like with a resin, a vertical rib and a horizontal reinforcement rib that are in contact with the surface of the base plate on the back surface side of the roof material main body, Is formed.
・ Patent Document 3 discloses a lightweight foamed porcelain tile building material that is molded by dry press working and fired, and the back of the tile building material has a peripheral ridge back foot on the periphery and a checkered pattern on the inside. In the figure, the back of the screw-like back foot is formed on the back side of the screw hole and the screw hole recess.
(Patent Documents 4 and 5 will be described later.)
Japanese Utility Model Publication No. 47-19222 JP 2003-193627 A Japanese Patent Laid-Open No. 7-3950 JP-A-10-29850 Japanese Patent Laid-Open No. 10-167801

  However, the protrusions (leg walls, ribs, soles) on the back surface of the tiles in Patent Documents 1 to 3 mainly reinforce the tile main body, and other than the tile main body, for example, those that reinforce the underlap so far There wasn't. Many flat roof tiles have an underlap on one side of the roof tile and an overlap on the other side. At the time of laying, most of the underlap is in a state where it floats from the ground surface. Therefore, when the thickness of the underlap is reduced, a decrease in bending strength becomes a problem.

  In addition, in the present invention, it is a new requirement that the middle part of the underlap flow direction (head bottom direction) is nailed (used in a concept including screwing) to the ground or pier. As a result, there is a risk that the underlap floating from the field will break as described above.

  Therefore, the present invention can obtain the required step cracking strength even if the wall thickness of the tile main body and the underlap is reduced, and not only can reduce the weight, but also provide an intermediate portion in the flow direction of the underlap. It is an object of the present invention to provide a flat roof tile that can be nailed on a field ground or a pier to improve wind resistance, and can prevent cracking of an underlap due to an impact at the time of nailing.

  It is another object of the present invention to provide a method for producing a flat roof tile that is difficult to be deformed and can be efficiently manufactured with energy saving, equipment saving, and labor saving.

[Invention of flat roof tiles]
The present invention is a ceramic flat tile, having an underlap on one side of the tile body, an overlap on the other side of the tile body, protruding downward on the back surface of the tile body, and contacting the ground The bottom support foot is formed on the back of the underlap, and the underlap support foot that touches the ground is formed on the back of the underlap. A lap nail hole is formed.

  The bottom of the roof of the tile body is formed with an upwardly protruding bottom water return, and the lower end of the roof of the roof of the tile body is lower than the bottom of the underlap. The lower edge of the head of the upper flat roof tile is located in contact with the surface of the roof tile when it is installed. It is preferable that the back surface of the underlap does not come into contact with the surface of the bottom portion water return. Furthermore, it is preferable that the surface of the bottom part water return at the position immediately below is set lower than the surface of the bottom part water return formed in an overlap.

(1) The mode of the tile body support foot will be exemplified below.
(1-1) A mode in which the tile main body support feet are rib-shaped tile main body support feet that are formed at a plurality of positions spaced in the left-right direction on the back surface of the tile main body and extend continuously in the flow direction.
The number of the plurality of locations (the number of rib-shaped roof tile support legs) is preferably 3 to 6.
It is preferable that the rib-shaped roof tile support legs have a tapered shape in a side view in which a protruding height downward from the back surface of the roof tile body increases as it goes from the bottom side to the head side.
A notch portion can be formed in an intermediate portion (for example, a corresponding portion of an underlap nail hole to be described later) in the rib-shaped roof tile main body support foot, and a crosspiece can be hooked on the notch portion.

(1-2) A mode in which the tile main body support feet are split rib-shaped tile main body support feet that are formed at a plurality of positions spaced in the left-right direction on the back surface of the tile main body and extend intermittently in the flow direction.
The split rib-shaped roof tile support legs can be formed by dividing the rib-shaped roof tile support legs having the contents described in (1-1) above in the flow direction. It is also possible to hook a pier to the part missing in this division.
Multiple split rib-shaped tile body support feet so that there are always two or more tile body support feet on the left and right lines when the back side of the tile body is scanned with the left and right lines from the bottom side to the head side Are preferably divided in a zigzag pattern. This is to ensure that the tile body support foot is stably placed on the hearth roller when firing with a roller hearth kiln described later.

(1-3) A mode in which the tile main body support feet are a large number of dispersed interspersed tile main body support feet formed dispersed over substantially the entire back surface of the tile main body.
The number of dispersed interspersed tile main body support legs is preferably 9-50.

(2) The mode of the underlap support foot is illustrated next.
(2-1) A mode in which the underlap support foot is a rib-like underlap support foot that continuously extends on the back surface of the underlap in the flow direction.
The underlap support legs are preferably provided at one or two locations on the back surface of the underlap, and one of the locations is preferably the side edge of the back surface of the underlap.
It is preferable that the rib-like underlap support leg has a tapered shape in a side view in which a protruding height from the back surface of the underlap increases as it goes from the buttocks side to the head side.
An underlap nail hole can be formed so as to penetrate the rib-like underlap support foot in the tile thickness direction.
A notch is formed at the location corresponding to the underlap nail hole in the rib-shaped underlap support foot, an underlap nail hole is opened at the bottom of the notch, a pier is hooked into the notch, and an underlap nail hole is formed in the pier. You can also make nails.

(2-2) A mode in which the underlap support feet are split rib-like underlap support feet formed intermittently in the flow direction, which are formed at a plurality of positions spaced in the left-right direction on the back surface of the underlap.
The split rib-shaped underlap support legs can be formed by dividing the rib-shaped underlap support legs having the contents described in the above (2-1) in the flow direction. It is also possible to hook a pier to the part lacked in this division and hit a nail from the underlap to the pier.

(2-3) A mode in which the underlap support feet are a plurality of dispersed interspersed underlap support feet formed so as to be distributed over the majority of the flow direction length of the back surface of the underlap.
The number of dispersed interspersed underlap support legs is preferably 3-10.

(3) The mode of an underlap nail hole is illustrated next.
It is preferable that the middle direction of the underlap in which the underlap nail hole is provided is in a range of 10 to 80% of the length in the flow direction of the underlap from the head side edge of the underlap to the bottom side. It is more preferable that the range is 30 to 70%.
The number of underlap nail holes is preferably 1-2.
As described above, the underlap nail hole can be provided so as to penetrate the underlap support foot in the tile thickness direction. Further, when a notch is formed at a location corresponding to the underlap nail hole in the underlap support foot, a pier can be hooked on the notch and the nail can be hit on the pier.

[Invention of flat roof tile manufacturing method]
The present invention has an underlap on one side of the tile body, an overlap on the other side of the tile body, and a tile body support foot that protrudes downward on the back surface of the tile body and contacts the ground. A flat plate in which an underlap support leg that protrudes downward on the back surface of the underlap and contacts the ground is formed, and an underlap nail hole for nailing to the ground or a pier is formed in the middle of the underlap in the flow direction. A step of dry-molding the tile with clay having a moisture content of 4 to 12%,
Applying glaze to the visible portion of the flat roof tile;
And a step of placing the flat roof tile directly on a hearth roller of a roller hearth kiln in a horizontal posture with the tile main body support feet and the underlap support feet on the lower side.

  According to the flat roof tile of the present invention, even if the thickness of the roof tile and the underlap is reduced, the required tapping crack strength can be obtained, and not only the weight can be reduced, but also the flow direction of the underlap. Winding performance can be improved by nailing the intermediate portion to the ground or pier, and cracking of the underlap due to impact at the time of nailing can also be prevented.

  According to the method for producing a flat roof tile of the present invention, the flat roof tile having the above-described effects can be efficiently manufactured with low energy consumption, facility saving, and labor saving.

  A ceramic tile roof tile with an underlap on one side of the tile body, an overlap on the other side of the tile body, and a tile body support that protrudes downward on the back of the tile body and contacts the ground A foot is formed, and an underlap supporting foot that protrudes downward on the back surface of the underlap and contacts the ground is formed, and an underlap nail hole for nailing to the ground or a pier is formed in the middle of the flow direction of the underlap. Formed. The underlap nail hole is formed so as to penetrate the rib-like underlap support foot in the tile thickness direction. Alternatively, a notch is formed at a corresponding position of the underlap nail hole in the rib-like underlap support foot, an underlap nail hole is formed at the bottom of the notch, and a pier is hooked on the notch, A nail is struck from an underlap nail hole.

  The flat roof tile is formed by a dry molding process using clay having a moisture content of 4 to 12%, a step of applying glaze to the visible portion of the flat roof tile, and the flat roof tile support foot and the underlap support foot. It is manufactured through a process of placing and firing directly on a hearth roller of a roller hearth kiln in a horizontal posture on the lower side.

(Example 1)
1-7 has shown the flat roof tile 1 of Example 1, its baking method, and the installation state. This flat roof tile 1 is an integrally molded product made of ceramics and has a flat square roof tile body 2. The roof tile body 2 includes an intermediate portion 2a located in the middle in the left-right direction, and raised portions 2b and 2c extending in the flow direction that are raised in such a manner that both the front and back surfaces slide upward on both the left and right sides of the intermediate portion 2a. The raised portion 2b on the one side (left side in this example) is for the purpose of aesthetics to be shown alongside the raised portion 2c of the flat roof tile 1 adjacent to the same step, the purpose of improving the strength of the roof tile body 2 in terms of material mechanics, and the like. An underlap 3 is formed on the further left side. The surface of the underlap 3 is lower than the surface of the intermediate part 2a of the roof tile body 2, and the back surface of the underlap 3 is substantially the same level as the back surface of the intermediate section 2a of the roof tile body 2 (at the same level or within 2 mm below it). It is in. An underlap water turn 8 that protrudes upward is formed on the surface of the side edge and the bottom edge of the underlap 3. The raised portion 2 c on the other side (right side in this example) itself forms an overlap 4, and the underlap 3 of the flat roof tile 1 adjacent to the same step is inserted below the overlap 4.

  On the surface of the bottom part of the roof tile body 2 and the bottom part of the bottom part 2 is formed a bottom part 5 that protrudes upward. A nail hole 9 is formed. Further, the lower end of the head finding 6 (in this example, drooping) of the roof tile body 2 is lower than the back surface of the underlap 3. It is set to be lower than “5”. Then, the lower end of the head finding 6 of the upper flat roof tile 1 abuts against the surface of the intermediate portion 2a of the roof tile body 2 at the time of installation, so that the back surface of the underlap 3 of the upper flat roof tile 1 becomes the bottom water. It does not contact the surface of the barb 5. Moreover, the surface of the bottom part water return 5 of the location just below is set lower than the surface of the bottom part water return 5 formed in the right and left raised parts 2b and 2c. Further, a notch portion 7 into which the raised portions 2 b and 2 c of the lower flat roof tile 1 are fitted is formed at the center in the left-right direction of the head finding 6.

  Formed on the back surface of the tile body 2 is a tile body support foot 11 that protrudes downward and contacts the ground 20. The roof tile support legs 11 of the present embodiment are rib-shaped continuously extending in the flow direction formed at four positions spaced in the left-right direction on the back surface of the roof tile body 2 (in this embodiment, the intermediate portion 2a). It is a tile body support foot 11.

  An underlap support leg 12 is formed on the back surface of the underlap 3 so as to protrude downward and come into contact with the field 20. The underlap support foot 12 of the present embodiment is a rib-like underlap support foot 12 that continuously extends in the flow direction along the side edge of the back surface of the underlap 3.

  The tile main body support foot 11 and the underlap support foot 12 of the present embodiment have a protruding height downward from the back surface of the tile main body 2 and the back surface of the underlap 3, respectively, from the bottom side toward the head side. It becomes higher and tapered in a side view. In addition, the bottom end of the tile body support foot 11 and the underlap support foot 12 extends to the bottom end of the roof tile body 2, but the head side end of the tile body support foot 11 and the underlap support foot 12 is It ends at 10-20% of the flow direction length of the tile main body 2 from the head end (head finding 6) of the tile main body 2 to the bottom side. The end face at the head side end of the support foot 12 can come into contact with the end face of the bottom of the roof tile body 2 of the flat roof tile 1 at the time of installation.

  An underlap nail hole 13 for nailing to the field ground 20 or the pier is formed in the middle portion in the flow direction of the underlap 3. One underlap nail hole 13 of this embodiment is formed from the head side edge of the underlap 3 to the bottom side within a range of 30 to 50% of the length of the underlap in the flow direction. The underlap nail hole 13 is provided so as to penetrate the underlap support foot 12 in the tile thickness direction.

The thickness of each part of the flat roof tile 1 of a present Example is as follows.
・ Intermediate part 2a and raised parts 2b, 2c (overlap 4) of tile body 2: 5 to 8 mm (however, thickness that does not include tail part water return 5 and tile body support foot 11)
・ Under wrap 3: 5 to 7 mm (thickness not including under wrap water return 8 and under wrap support foot 12)
On the other hand, the tile body support foot 11 and the underlap support foot 12 have a protruding height of approximately 0 at the butt portion side end, 10-20 mm at the head side end, and a lateral width of 10-20 mm at the protruding base end. Since the protrusion tip is 5 to 15 mm, that is, it is thin, it does not significantly affect the weight increase of the flat roof tile 1.
Therefore, the flat roof tile 1 of the present embodiment is reduced to about ½ the weight of an average ceramic flat roof tile having a thickness of about 10 to 16 mm.

Next, the manufacturing method of the flat roof tile 1 is demonstrated in order of a process.
(1) Dry molding As described above, a flat roof tile 1 having a roof tile body 2, an underlap 3 and an overlap 4 and having a roof body support foot 11, an underlap support foot 12 and an underlap nail hole 13 is formed of gold. Using a mold (not shown), dry molding is performed with clay having a moisture content of 4 to 12%. The pressing pressure by the mold is preferably 1000 to 4000 N / cm ² .

(2) Glazing Apply glaze to the visible part of the flat roof tile after firing.

(3) Firing As shown in FIG. 4, the flat roof tile 1 after glazing is fired by a roller hearth 31. The roller hearth kiln 31 includes a furnace body 34 formed in a tunnel shape having an inlet 32 and an outlet 33. A large number of hearth rollers 35 extending in the transverse direction of the furnace body are provided in the furnace body 34 over the entire length in the furnace body length direction, and are rotationally driven by a driving device (not shown). Further, the furnace body 34 is provided with an upper burner 36 above the hearth roller 35 in the firing zone, and a lower burner 37 below the hearth roller 35.

  The dry-formed flat roof tile 1 is placed in a horizontal posture with the rib-shaped roof tile support legs 11 and the underlap support legs 12 on the lower side, and the head corner direction is parallel to the furnace body length direction. It is placed directly on 35 and travels in the furnace body 34. By carrying out like this, since the rib-shaped roof tile main body support foot 11 and the underlap support foot 12 are placed so as to be substantially orthogonal to the length direction of each hearth roller 35 and straddle the plurality of hearth rollers 35, it runs smoothly. . Thus, since baking is performed without using a baking cart or a baking jig, which is a separate member, with a small amount of heat shield around it, heat is easily transmitted to the flat roof tile 1 and energy saving can be achieved. In addition, since firing is performed in a substantially horizontal posture (flat firing), it is difficult to deform even if the thickness of each part of the flat roof tile 1 is thin. In addition, the equipment cost can be reduced, and the tile setting work on the baking cart and the baking jig becomes unnecessary.

  In addition, Patent Documents 4 and 5 listed above have the following description about firing roof tiles with a roller hearth kiln. However, these are the roof tiles placed on the hearth roller via various jigs, and it is not the idea to place the roof tiles directly on the hearth roller as in the present invention.

Patent Document 4 describes that a traveling setter is placed on a hearth roller, firing jigs are stacked on the traveling setter, and tiles are placed flat on the firing jig for firing.
-In Patent Document 5, a travel setter is mounted on a hearth roller, a support is installed on the travel setter, a support plate is tilted and supported on the support, and a roof tile is supported by tilting the support plate. And firing.

  Next, the installation state of the flat roof tile 1 will be described. The roof field 20 is formed, for example, by placing a waterproof underlaying material 22 on a field board 21, but is not limited thereto. As shown in FIGS. 5 to 7, when a large number of flat roof tiles 1 are installed in a staggered manner on the field ground 20, the adjacent flat roof tiles 1 in the same stage are inserted with the underlap 3 below the overlap 4. Rarely polymerizes. Further, the head of the upper flat roof tile 1 partially overlaps with the bottom of the lower flat roof tile 1, and the head of the upper flat roof tile 1 is formed on the surface of the intermediate portion 2 a of the roof main body 2 of the lower flat roof tile 1. The lower end of the part finding 6 comes into contact, and the back surface of the underlap 3 of the upper flat roof tile 1 is slightly separated from the surface of the bottom water return 5 of the lower flat roof tile 1. In addition, the projecting end surfaces of the tile body support foot 11 and the underlap support foot 12 are in contact with the field surface 20. The end surfaces at the head side ends of the tile main body support feet 11 and the underlap support feet 12 are in contact with or close to the bottom end surfaces of the tile main body 2 of the lower flat roof tile 1. A nail (including a screw) 14 is nailed to the field ground 20 through the bottom nail hole 9 and the underlap nail hole 13.

As described in detail above, according to the flat roof tile 1 of the first embodiment, the following operational effects can be obtained.
(1) The flat roof tile 1 is lightened to a weight of about ½ due to the reduction of the wall thickness as compared with the conventional ceramic flat roof tile.
(2) Since the protruding end surface of the tile body support foot 11 is in contact with the ground surface 20, the tile body 2 is backed up from the back side, so that the required tapping strength is obtained despite the reduction in wall thickness. Can do.
(3) The roof tile body 2 and the underlap 3 are reinforced by the rib-shaped roof tile support legs 11 and the underlap support legs 12, and are not easily deformed.
(4) The wind resistant performance can be enhanced by nailing the intermediate portion of the underlap 3 in the flow direction to the field surface 20.
(5) Since the underlap 3 is backed up and supported from the back side by contacting the projecting end surface of the underlap support foot 12 to the ground surface 20, the underlap support foot 12 is separated from the surface of the bottom butt water return 5. First, it is possible to prevent cracking of the underlap 3 due to the impact when nailing (4).

(Example 2)
Next, FIG. 8 shows a flat roof tile 1 of the second embodiment. The flat roof tile 1 of the present embodiment has a rib-like underside in that a raised portion 2d is provided at the center in the left-right direction of the middle portion 2a of the roof tile body 2 so that the front and back surfaces slide together. A notch 15 for hooking the crosspiece 23 is formed at a position corresponding to the underlap nail hole 13 in the lap support foot 12 (the front and rear positions including the position of the underlap nail hole 13). This is different from the first embodiment in that the lap nail hole 13 is opened, and the rib-like roof tile support foot 11 is provided with a notch 16 at the same flow direction position as the notch 15, and the others are implemented. This is the same as Example 1.

  In the present embodiment, at the time of laying, the notches 15 and 16 are hooked on the crosspiece 23 attached to the field ground 20, and the nail 14 is nailed to the crosspiece 23 in the notch 15 through the underlap nail hole 13. Therefore, according to the flat roof tile 1 of the present embodiment, in addition to the same effects as those of the first embodiment, wind resistance performance that can cope with stronger wind pressure is obtained.

(Example 3)
Next, FIGS. 9-11 has shown the flat roof tile 1 of Example 3. FIG. In the flat roof tile 1 of the present embodiment, the number of rib-shaped roof tile support legs 11 is increased to five, and the flow direction positions of the bottom side edge and the head side edge of the tile body support legs 11 are the left and right roof tiles. As the number of rib-like underlap support legs 12 increases to two, the main support legs 11 are slightly displaced alternately (however, the protruding height of each support leg 11 is substantially the same when viewed in the left-right direction), and The position in the flow direction of the bottom end and the head end of the underlap support foot 12 is slightly shifted between the left and right support feet 12 (however, the protruding height of each support foot 12 is substantially the same when viewed in the left-right direction) ) Are different from those of the first embodiment, and the others are the same as those of the first embodiment.

  According to the flat roof tile 1 of the present embodiment, in addition to the same effects as those of the first embodiment, it is possible to further increase the bending strength of the underlap 3 and more reliably prevent cracking due to impact.

Example 4
Next, FIG. 12 shows a flat roof tile 1 of the fourth embodiment. The flat roof tile 1 of the present embodiment is different from the third embodiment in that the roof tile support legs 11 are split rib-shaped roof tile support legs 11 that extend intermittently in the flow direction. 3 and common. When the back surface of the tile body 2 is scanned from the bottom side to the head side with the left and right lines, the split rib-shaped tile body support legs 11 are always present so that two or more tile body support legs 11 are present on the left and right lines. Is divided into a staggered pattern. Thereby, when baking with a roller hearth kiln, the tile main body support leg 11 mounts stably on a hearth roller. Also with the flat roof tile 1 of the present embodiment, the same operational effects as those of the first embodiment can be obtained.

  In addition, this invention is not limited to the said Example, In the range which does not deviate from the meaning of invention, it can change suitably and can be actualized.

(A) which shows the flat roof tile of Example 1 of this invention is a perspective view of the surface side, (b) (c) is a perspective view of a back surface side. (A) which shows the flat roof tile is a top view, (b) is a bottom view. (A) is a front view showing the flat roof tile, (b) is a rear view, (c) is a sectional view taken along line IIIc-IIIc in FIG. 2, (d) is a left side view, (e) is a right side view, f) is a sectional view taken along line IIIf-IIIf in FIG. (A) which shows the roller hearth kiln which bakes the flat roof tile is a cross-sectional view, (b) is a longitudinal cross-sectional view. It is a perspective view of the surface side which shows the state at the time of the installation of the flat roof tile. It is a perspective view of the back surface side which shows the state at the time of the installation of the flat tile. It is a right side surface which shows the state at the time of the installation of the flat roof tile. (A) which shows the flat roof tile of Example 2 of this invention is a perspective view of the surface side, (b) (c) is a perspective view of a back surface side. (A) which shows the flat roof tile of Example 3 of this invention is a perspective view of the surface side, (b) (c) is a perspective view of the back surface side. (A) which shows the flat roof tile is a top view, (b) is a bottom view. (A) is a front view, (b) is a rear view, (c) is a cross-sectional view taken along line XIc-XIc in FIG. 2, (d) is a left side view, (e) is a right side view, f) is a sectional view taken along line XIf-XIf in FIG. (A) which shows the flat roof tile of Example 4 of this invention is a perspective view of the surface side, (b) (c) is a perspective view of a back surface side.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Flat roof tile 2 Tile body 2a Middle part 3 Under wrap 4 Overlap 5 Bottom part water return 7 Notch part 8 Under lap water return 9 Bottom part nail hole 11 Tile body support foot 12 Under wrap support leg 13 Under wrap nail hole 14 Nail 15 Notch 16 Notch 20 Field Ground 21 Field Plate 22 Underlaying Material 23 Pier 31 Roller Hearth Kiln 35 Hearth Roller

Claims (4)

  A ceramic flat tile (1) having an underlap (3) on one side of the tile body (2) and an overlap (4) on the other side of the tile body (2) A roof tile support foot (11) that protrudes downward on the back surface of the base and contacts the ground (20) is formed, and an underlap support foot that protrudes downward on the back surface of the underlap (3) and contacts the ground (20). (12) is formed, and an underlap nail hole (13) for nailing to the field ground (20) or the pier (23) is formed in the middle of the flow direction of the underlap (3). Flat roof tiles.   The flat roof tile according to claim 1, wherein the underlap nail hole (13) is formed so as to penetrate the rib-like underlap support foot (12) in the tile thickness direction.   A notch (15) is formed at a location corresponding to the underlap nail hole (13) in the rib-like underlap support foot (12), and the underlap nail hole (13) opens at the bottom of the notch (15). The flat roof tile according to claim 1, wherein a crosspiece (23) is hooked on the notch (15), and a nail (14) is driven from the underlap nail hole (13) to the crosspiece (23). It has an underlap (3) on one side of the roof tile body (2), an overlap (4) on the other side of the roof tile body (2), and projects downward on the back surface of the roof tile body (2). A tile body support foot (11) for grounding is formed on (20), and an underlap support foot (12) for projecting downward on the back surface of the underlap (3) and contacting the ground (20) is formed. A flat roof tile (1) in which an underlap nail hole (13) for nailing to a field surface (20) or a pier (23) is formed in the middle part in the flow direction of (3), has a moisture content of 4 to 12%. A process of dry molding with clay of
Applying glaze to the visible portion of the flat roof tile (1);
The flat roof tile (1) is directly placed on the hearth roller (35) of the roller hearth kiln (31) and fired in a horizontal posture with the roof tile support legs (11) and the underlap support legs (12) on the lower side. A method for producing a flat roof tile comprising the steps of:

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