Clipboard

Abstract

To provide a clip board with excellent convenience.SOLUTION: A clipboard has fixing means for fixing the board body in a pedestal state, the fixing means having: a fastening member attached to a hinge portion so as to be displaceable along a first direction within a range including a first position and a second position that are apart from each other in the first direction; a first engagement portion provided on a first board portion; and a second engagement portion provided on a second board portion. When the board body is in the pedestal state and the fastening member is in the first position, the fastening member engages with the first and second engagement portions, thereby restricting the rotation of the first and second board portions, and when the board body is in the pedestal state and the fastening member moves from the first position to the second position, the fastening member is disengaged from the first and second engagement portions.SELECTED DRAWING: Figure 2

Description

【Technical Field】 【0001】 The present invention relates to a clipboard. 【Background Art】 【0002】 Conventionally, a clipboard including a plate-shaped board body and a clamping tool capable of clamping pieces of paper such as documents and sheets between the board body has been widely used. Since the board body of the clipboard functions as a base plate for reading and writing on pieces of paper, it is convenient for use in a standing position or outdoors. As a clipboard, a foldable clipboard that can be folded and maintained in an expanded state by a rod that can prevent bending is known (for example, Patent Document 1). 【Prior Art Documents】 【Patent Documents】 【0003】 【Patent Document 1】 Registered Utility Model No. 3148952 【Patent Document 2】 Japanese Utility Model Laid-Open No. 63-101583 【Patent Document 3】 Japanese Patent Laid-Open No. 2019-151086 【Patent Document 4】 Japanese Patent No. 5367791 【Summary of the Invention】 【Problems to be Solved by the Invention】 【0004】 A foldable clipboard with better convenience is desired. 【0005】 An object of the present invention is to provide a clipboard with excellent convenience. 【Means for Solving the Problems】 【0006】 To solve the aforementioned problems, the present invention employs the following configuration. That is, the present invention provides a clipboard comprising a plate-shaped board body having a front surface and a back surface, and a clipping device capable of holding a piece of paper between itself and the board body, wherein the board body includes a plate-shaped first plate portion and a plate-shaped second plate portion, and a hinge portion extending in a predetermined first direction and rotatably connecting the first plate portion and the second plate portion, wherein the board body can be switched between a base plate state in which the board body forms a flat plate shape by the rotation of the first plate portion and the second plate portion around the hinge portion, and a folded state in which the board body is folded at the hinge portion such that the front surfaces of the first plate portion and the second plate portion face each other, and the clipboard further comprises fixing means provided on the back surface of the board body capable of fixing the board body in the base plate state The fixing means comprises a locking member attached to the hinge portion so as to be displaceable along the first direction within a range including a first position and a second position that are separated from each other in the first direction, a first engaging portion provided on the first plate portion, and a second engaging portion provided on the second plate portion, wherein when the board body is in the base plate state and the locking member is in the first position, the locking member engages with the first engaging portion and the second engaging portion, thereby restricting the rotation of the first plate portion and the second plate portion, and when the board body is in the base plate state and the locking member moves from the first position to the second position, the engagement between the locking member and the first engaging portion and the second engaging portion is released, thereby allowing the rotation of the first plate portion and the second plate portion to be permitted. 【0007】 According to the present invention, since the board body can be fixed in a base plate state by the fixing means, the first plate portion and the second plate portion can be prevented from rotating unintentionally. Therefore, the clipboard can be used stably as a base plate for reading and writing on paper. This improves the usability of the board. Furthermore, the board's fixation to the base plate can be released simply by moving (displacing) the locking member from the first position to the second position along the first direction. This makes it easy to switch the board from the base plate state to the folded state. As a result, usability can be further improved. 【0008】 Furthermore, in the present invention, the locking member has a first locking portion that engages with the first engaging portion and a second locking portion that engages with the second engaging portion, wherein one of the first engaging portion and the first locking portion is formed as a projection and the other is formed as a hole into which the projection fits when the board body is in the base plate state and the locking member is in the first position, and the other of the second engaging portion and the second locking portion is formed as a projection and the other is formed as a hole into which the projection fits when the board body is in the base plate state and the locking member is in the first position. 【0009】 Furthermore, in the present invention, the locking member is configured such that it can engage with the first engaging portion and the second engaging portion when the board body switches from the folded state to the base plate state while the locking member is in the first position, and the fixing means may further include a biasing member that biases the locking member from the side of the second position to the side of the first position. 【0010】 Furthermore, in the present invention, the fixing means further comprises a restricting portion provided on at least one of the first plate portion and the second plate portion, which engages with the locking member when the board body is in the base plate state and the locking member is in the second position, thereby restricting the movement of the locking member from the second position side to the first position side, and the engagement between the restricting portion and the locking member may be released when the first plate portion and the second plate portion rotate around the hinge portion so that the board body is in the folded state when the board body is in the base plate state and the locking member is in the second position. 【0011】 Furthermore, in the present invention, the clamping device may be provided on one of the first plate portion and the second plate portion, and clamps one end of the paper piece in a second direction perpendicular to the first direction between itself and the first plate portion, and the other of the first plate portion may have an insertion portion formed therein into which the other end of the paper piece in the second direction can be inserted. 【0012】 Furthermore, the clipboard according to the present invention may further include a cover member provided on the back surface of the board body so as to cover the fixing means, and a holding member that holds the cover member so that the cover member can slide along the board body in a second direction perpendicular to the first direction. 【0013】 Furthermore, the clipboard according to the present invention may further include a pen holder member that can switch between a stored state in which the pen is housed within the board body and a usage state in which the pen protrudes from the edge of the board body to the outside of the board body. [Effects of the Invention] 【0014】 According to the present invention, a clipboard with superior convenience can be provided. [Brief explanation of the drawing] 【0015】 [Figure 1] Figure 1 is a perspective view of the clipboard in its base state, seen from the front. [Figure 2] Figure 2 is a perspective view of the clipboard in its base state, seen from the back. [Figure 3] Figure 3 is a side view of the clipboard in its base plate configuration. [Figure 4] Figure 4 is a side view of the clipboard in its folded state. [Figure 5] Figure 5 is an exploded perspective view of the clipboard, illustrating the components located on the front side of the board itself. [Figure 6] Figure 6 is an exploded perspective view of the clipboard, illustrating the components located on the back of the board itself. [Figure 7]FIG. 7 is a plan view when the board body in the unfolded state is viewed from the front side. [Figure 8] FIG. 8 is a plan view when the board body in the unfolded state is viewed from the back side. [Figure 9] FIG. 9 is a plan view when the panel for holder storage in the unfolded state is viewed from the back side. [Figure 10] FIG. 10 is a plan view when the vicinity of the hinge portion of the board body in the unfolded state is viewed from the back side. [Figure 11] FIG. 11 is a plan view when the flap plate is viewed from the front side. [Figure 12] FIG. 12 is a plan view when the flap plate is viewed from the back side. [Figure 13] FIG. 13 is a sectional view taken along the line A-A of FIG. 1. [Figure 14] FIG. 14 is a plan view when the first cover plate is viewed from the front side. [Figure 15] FIG. 15 is a plan view when the first cover plate is viewed from the back side. [Figure 16] FIG. 16 is a plan view when the second cover plate is viewed from the front side. [Figure 17] FIG. 17 is a plan view when the second cover plate is viewed from the back side. [Figure 18] FIG. 18 is a plan view when the slide member is viewed from the front side. [Figure 19] FIG. 19 is a plan view when the slide member is viewed from the back side. [Figure 20] FIG. 20 is a sectional view taken along the line B-B of FIG. 18. [Figure 21] FIG. 21 is a sectional view taken along the line C-C of FIG. 18. [Figure 22] FIG. 22 is a plan view when the vicinity of the fixing means of the clipboard in the flat state is viewed from the back side, showing the state where the slide member is in the first position. [Figure 23]Figure 23 is a plan view of the area around the fixing mechanism of a flat clipboard, as seen from the back, showing the slide member in the second position. [Figure 24] Figure 24 is a schematic cross-sectional view showing the DD section of Figure 22. [Figure 25] Figure 25 shows the area near the contact projection when the board body is in the base plate state and the sliding member is in the first position. [Figure 26] Figure 26 shows the area near the contact projection when the board body is in the base plate state and the sliding member is in the second position. [Figure 27] Figure 27 is a schematic cross-sectional view showing the EE section of Figure 23. [Figure 28] Figure 28 is a schematic cross-sectional view showing the cross-section of a folded clipboard. [Figure 29] Figure 29 is a schematic cross-sectional view showing the clipboard during the transition from the folded state to the base state. [Figure 30] Figure 30 is a plan view of the cover sheet as seen from the front. [Figure 31] Figure 31 is a plan view of the area around the cover sheet of a flat clipboard, as seen from the back. [Figure 32] Figure 32 is a plan view of the fixing plate as seen from the front. [Figure 33] Figure 33 is a plan view of the fixing plate as seen from the back. [Figure 34] Figure 34 is a plan view of the area around the fixing plate of a flat clipboard, as seen from the back. [Figure 35] Figure 35 is a plan view of the retaining sheet as seen from the front. [Figure 36] Figure 36 is a plan view of a clipboard in a flat state, holding a piece of paper, as seen from the front. [Figure 37] Figure 37 is a plan view of the pen holder plate as seen from the front. [Figure 38]Figure 38 is a plan view of the pen holder plate as seen from the back. [Figure 39] Figure 39 is a plan view of the area around the pen holder plate of a flat clipboard, as seen from the back, and shows the pen holder plate in its stored position. [Figure 40] Figure 40 is a plan view of the area around the pen holder plate of a flat clipboard, as seen from the back, illustrating the state of use of the pen holder plate. [Modes for carrying out the invention] 【0016】 Embodiments of the foldable clipboard according to the present invention will be described below with reference to the drawings. Note that the configurations of the following embodiments are illustrative, and the present invention is not limited to the configurations of these embodiments. In this specification, "base plate state" and "folded state" refer to the state of the board body, but for convenience, the state of the foldable clipboard when the board body is in the base plate state may be referred to as the "base plate state," and the state of the foldable clipboard when the board body is in the folded state may be referred to as the "folded state." 【0017】 Figure 1 is a perspective view of the foldable clipboard 100 (hereinafter referred to as clipboard 100) in its base plate state according to the embodiment, viewed from the front. Figure 2 is a perspective view of the clipboard 100 in its base plate state according to the embodiment, viewed from the back. Figures 1 and 2 show the clipboard 100 when the board body, indicated by reference numeral 1, is in the base plate state. Figure 3 is a side view of the clipboard 100 in its base plate state according to the embodiment. Figure 4 is a side view of the clipboard 100 in its folded state according to the embodiment. The clipboard 100 is configured so that the orientation of the board body 1 can be switched between an expanded base plate state as shown in Figures 1 to 3 and a folded state as shown in Figure 4, where it is folded in half. 【0018】 As shown in Figures 1 to 3, the clipboard 100 in its base state has a flat shape that is generally rectangular (more specifically, rectangular) in plan view. Hereinafter, for each direction of the clipboard 100, the vertical direction, horizontal direction, and thickness direction are defined with respect to the clipboard 100 in its base state, as indicated by the arrows in Figures 1 to 3. The shorter side of the clipboard 100 in plan view is defined as the "horizontal direction" (an example of a "predetermined first direction"), and the longer side of the clipboard 100 in plan view is defined as the "vertical direction" (an example of a "second direction"). The vertical direction (second direction) is perpendicular to the horizontal direction (first direction). The thickness direction (third direction) is perpendicular to both the horizontal direction (first direction) and the vertical direction (second direction). Plan view refers to viewing the clipboard 100 along the thickness direction. Furthermore, of the two sides of the clipboard 100 in the thickness direction, the side visible in Figure 1 is referred to as the "front side," and the side visible in Figure 2 is referred to as the "back side." In the thickness direction of the clipboard 100, the front side of the clipboard 100 is referred to as the "front side," and the back side of the clipboard 100 is referred to as the "back side." In the vertical direction of the clipboard 100, the side on which the clamping device indicated by reference numeral 10 is provided is referred to as the "upper side," and the side on which the retaining sheet indicated by reference numeral 8 is provided is referred to as the "lower side." In the horizontal direction of the clipboard 100, the side on which the recess indicated by reference numeral D1 is provided is referred to as the "left side," and the opposite side is referred to as the "right side." However, these directions of the clipboard 100 are defined for the convenience of explanation and are not intended to limit the present invention. 【0019】 As shown in Figure 1, the clipboard 100 comprises a plate-shaped board body 1 having a front surface S1 and a back surface S2. In its base plate state, the board body 1 forms a single (one) flat plate and functions as a base plate for reading and writing on paper. When the board body 1 is used as a base plate, the paper is placed, for example, on the front surface S1 of the board body 1. The clipboard 100 further comprises a clamping device 10 provided at the upper end of the front side of the board body 1, which can hold a paper (for example, a document or paper) between itself and the front surface S1 of the board body 1. By holding the paper between the board body 1 and the clamping device 10, the paper placed on the board body 1 is prevented from falling off the clipboard 100. 【0020】 The board body 1 is formed as a single panel and, before assembling the clipboard 100, is in the unfolded state (unfolded state) shown in Figures 7 and 8. The board body 1 is folded in predetermined places, resulting in the assembled state shown in Figures 1 to 4 of the finished clipboard 100. 【0021】 As shown in Figure 1, the board body 1 includes a plate-shaped first plate portion 11 and a plate-shaped second plate portion 12, and a hinge portion 13 that extends in the left-right direction (a predetermined first direction) and rotatably connects the first plate portion 11 and the second plate portion 12. The hinge portion 13 is formed in the shape of a plate that is a rectangle with the longer side in the left-right direction when viewed from above, and is formed at the center of the board body 1 in the vertical direction, extending over the entire area of ​​the board body 1 in the left-right direction. The first plate portion 11 and the second plate portion 12 are formed in the shape of a plate that is a square shape (more specifically, a rectangle with the longer side in the left-right direction) when viewed from above, and their size and shape are generally the same. Specifically, the first plate portion 11 and the second plate portion 12 are formed in the shape of a rectangle with the same length in the vertical direction (hereinafter also referred to as the vertical width) and the same length in the left-right direction (hereinafter also referred to as the left-right width). Therefore, the assembled board body 1 has a vertically symmetrical shape in the plan view with the hinge portion 13 as the axis of symmetry. In the board body 1, the first plate portion 11 is positioned on the upper side, and the second plate portion 12 is positioned on the lower side. The lower edge of the first plate portion 11 is connected to the upper edge of the hinge portion 13, and the upper edge of the second plate portion 12 is connected to the lower edge of the hinge portion 13. In this way, the first plate portion 11 and the second plate portion 12 are connected via the hinge portion 13. 【0022】 Here, the lower edge of the first plate portion 11 and the upper edge of the hinge portion 13 are connected via a hinge wire L1 extending in the left-right direction (first direction). The first plate portion 11 is rotatable relative to the hinge portion 13 with the hinge wire L1 as its pivot axis. Also, the upper edge of the second plate portion 12 and the lower edge of the hinge portion 13 are connected via a hinge wire L2 extending in the left-right direction (first direction). The second plate portion 12 is rotatable relative to the hinge portion 13 with the hinge wire L2 as its pivot axis. In other words, the first plate portion 11 and the second plate portion 12 are rotatable around the hinge portion 13. 【0023】 The board body 1 is preferably moderately rigid and, more preferably, lightweight in order to function as a base plate for reading and writing on paper pieces when the clipboard 100 is in its base plate state. From this viewpoint, in this embodiment, the board body 1 is made of a plastic plate formed from a resin material. Polycarbonate is an example of the resin material that forms the board body 1. However, the material of the board body according to the present invention is not limited to this. In the clipboard 100 according to this embodiment, the thickness of the board body 1 is made thinner at the hinge lines L1 and L2 than at other parts, making it easier to bend the board body 1 at the hinge lines L1 and L2. As a result, the first plate portion 11 and the second plate portion 12 can rotate around the hinge portion 13. 【0024】 The board body 1 can be switched between a base plate state and a folded state by the first plate portion 11 and the second plate portion 12 rotating around the hinge portion 13. As shown in Figure 4, in the folded state, the board body 1 is folded at the hinge portion 13 so that the surfaces S1 of the first plate portion 11 and the second plate portion 12 face each other. As a result, the clipboard 100 is more compact in the folded state than in the base plate state. Therefore, the portability of the clipboard 100 is improved by putting it in the folded state, making it easier to carry. As shown in Figure 4, in the folded state, the upper end of the first plate portion 11 and the lower end of the second plate portion 12 overlap (are in contact) in the thickness direction. 【0025】 Figures 5 and 6 are exploded perspective views of the clipboard 100. Figure 5 shows the components provided on the front side of the board body 1, and Figure 6 shows the components provided on the back side of the board body 1. For convenience, Figures 5 and 6 show simplified representations of the components of the clipboard 100. As shown in Figures 5 and 6, the clipboard 100 consists of a board body 1, a flap plate 2, a sliding member 3 (an example of a "locking member"), a first cover plate 4 (an example of a "holding member"), a second cover plate 5 (an example of a "holding member"), a cover sheet 6 (an example of a "cover member"), a fixing plate 7, a retaining sheet 8, and a pen holder plate. The device comprises 9 (an example of a "pen holder member"), a fixing band B1, a leaf spring SP1, and a compression spring SP2 (an example of a "biasing member"). 【0026】 As shown in Figure 5, a flap plate 2 and a retaining sheet 8 are attached to the surface S1 of the board body 1. The flap plate 2 is attached to the upper end of the first plate portion 11 via a leaf spring SP1. The clamping device 10 is formed by the flap plate 2 and the leaf spring SP1. The retaining sheet 8 is attached to the lower end of the second plate portion 12 by being sandwiched between a retaining sheet fixing panel 14 provided on the board body 1 and the second plate portion 12. 【0027】 As shown in Figure 6, a slide member 3, a first cover plate 4, a second cover plate 5, a cover sheet 6, a fixing plate 7, a pen holder plate 9, a compression spring SP2, and a fixing band B1 are attached to the back surface S2 of the board body 1. The slide member 3 is attached to the hinge portion 13 together with the compression spring SP2. The cover sheet 6 is attached from the front side, overlapping the slide member 3, and straddling the first plate portion 11 and the second plate portion 12. The first cover plate 4 is attached to the first plate portion 11 from the front side, overlapping the cover sheet 6. The second cover plate 5 is attached to the second plate portion 12 from the front side, overlapping the cover sheet 6. The fixing plate 7 is attached to the hinge portion 13 from the front side, overlapping the cover sheet 6. The pen holder plate 9 is attached to the upper end of the first plate portion 11 by being stored between the holder storage panel 16 provided on the board body 1 and the first plate portion 11. The fixing band B1 is attached to the first plate portion 11. A first engaging projection 17 is provided along the lower edge of the first plate portion 11, and a second engaging projection 57 is provided along the upper edge of the second cover plate 5. The fixing means 20 is composed of the slide member 3, the first engaging projection 17, the second engaging projection 57, and the compression spring SP2. As will be described in detail later, the fixing means 20 can fix the board body 1 in a base plate state. The following describes the various components of the clipboard 100. In the following description, if one end of a member is a fixed end and the other end is a free end in one direction, the fixed end side may be referred to as the "base end side" of the member, and the free end side may be referred to as the "tip end side" of the member. For example, for the first plate portion 11 and the second plate portion 12, the side with the hinge portion 13 may be referred to as the "base end side" in the vertical direction, and the side opposite the hinge portion 13 may be referred to as the "tip end side" in the vertical direction. 【0028】 [Board body] Figure 7 is a plan view of the unfolded board body 1 as seen from the front. Figure 8 is a plan view of the unfolded board body 1 as seen from the back. As described above, the board body 1 is formed as a single panel, and before assembling the clipboard 100, it is in the unfolded state shown in Figures 7 and 8. When predetermined parts are folded, the finished clipboard 100 is in the assembled state shown in Figures 1 to 4. 【0029】 As described above, the board body 1 includes a plate-shaped first plate portion 11 and a plate-shaped second plate portion 12, and a hinge portion 13 that extends in the left-right direction and rotatably connects the first plate portion 11 and the second plate portion 12. As shown in Figures 7 and 8, the board body 1 further includes a panel 14 for fixing the retaining sheet, a panel 15 for fixing the band, and a panel 16 for storing the holder. 【0030】 The retaining sheet fixing panel 14 is formed in the shape of a rectangular plate with its length elongated horizontally in a plan view, and is provided on the lower edge of the second plate portion 12. More specifically, the upper edge of the retaining sheet fixing panel 14 is connected to the lower edge of the second plate portion 12. The width of the retaining sheet fixing panel 14 is the same as the width of the second plate portion 12. As shown in Figure 1, the retaining sheet fixing panel 14 is folded to the front side in the clipboard 100 (i.e., in the assembled state) to sandwich the retaining sheet 8 between itself and the second plate portion 12. In the assembled state, the retaining sheet fixing panel 14 is folded to the front side, so the back surface of the retaining sheet fixing panel 14 in the unfolded state constitutes the surface S1 of the board body 1 in the assembled state. 【0031】 As shown in Figures 7 and 8, the retaining sheet fixing panel 14 has protrusions P1, P2, and P9 that project in the thickness direction. Protrusions P1 and P2 have a rectangular cross-section and are formed on the surface of the retaining sheet fixing panel 14 when it is unfolded. In this example, multiple (three in this example) protrusions P1 are arranged side by side in the left-right direction near the base end of the retaining sheet fixing panel 14. Protrusions P2 are provided one on each side near the left and right side edges of the retaining sheet fixing panel 14, at positions opposite to each other. Protrusion P9 is cylindrical and is formed on the back surface of the retaining sheet fixing panel 14 when it is unfolded. Protrusion P9 is located near the base end of the retaining sheet fixing panel 14, and is provided one on each side near the left and right side edges of the retaining sheet fixing panel 14, at positions opposite to each other. As shown in Figure 1, in the assembled state of the board body 1, the retaining sheet fixing panel 14 is folded to the front side, so that the protrusions P9 are positioned on the surface S1 of the board body 1. 【0032】 As shown in Figures 7 and 8, the second plate portion 12 has holes H5 drilled in the thickness direction. The holes H5 have a rectangular cross-section, and in this example, multiple (three in this example) holes H5 are arranged side by side in the left-right direction near the tip of the second plate portion 12. The holes H5 are located at positions corresponding to the projections P1 of the retaining sheet fixing panel 14 that are folded to the front side in the clipboard 100 (i.e., in the assembled state), and are configured to engage with the projections P1. In addition, rectangular recesses D3 are formed on the left and right side edges of the second plate portion 12. The recesses D3 are located at positions corresponding to the projections P2 of the retaining sheet fixing panel 14 that are folded to the front side in the clipboard 100, and are configured to engage with the projections P2. 【0033】 Furthermore, as shown in Figure 7, holes H1 are formed on the surface of the first plate portion 11, drilled in the thickness direction. The holes H1 are non-through holes with a circular cross-section formed on the surface S1 of the first plate portion 11, and are located near the tip (upper end) of the first plate portion 11. There are two holes H1, one on each side near the left and right edges of the first plate portion 11, positioned opposite each other. The holes H1 are positioned to correspond to the projections P9 of the retaining sheet fixing panel 14 that are folded to the front side in the assembled state, and are configured to receive the projections P9 when the board body 1 is folded. This prevents the tip (upper end) of the first plate portion 11 and the tip (lower end) of the second plate portion 12, which overlap each other in the thickness direction when folded, from shifting (relatively moving) in the vertical and horizontal directions. In other words, the first plate portion 11 and the second plate portion 12 are positioned when folded. 【0034】 The band fixing panels 15 are formed in the shape of a plate (more specifically, a small piece) which is a long rectangle in the vertical direction when viewed from above, and one is provided on each of the left and right side edges of the first plate portion 11, at positions opposite to each other. More specifically, of the pair of band fixing panels 15, 15, the left edge of one is connected to the right edge of the first plate portion 11, and the right edge of the other is connected to the left edge of the first plate portion 11. The band fixing panels 15 are positioned between the center of the first plate portion 11 and the tip (upper end) of the first plate portion 11 in the vertical direction. As shown in Figure 1, the band fixing panels 15 are folded to the front side in the assembled state, so that the end of the fixing band B1 is sandwiched between them and the first plate portion 11, as shown in Figure 2. As shown in Figure 7, protrusions P3 are formed on the surface of the band fixing panels 15 in the unfolded state. The protrusions P3 have a rectangular cross-section and one is provided on each of the tip of the left and right band fixing panels 15. 【0035】 As shown in Figures 7 and 8, the first plate portion 11 has holes H2 and H3 drilled in the thickness direction. Hole H2 is a through hole with a rectangular cross-section, and one is provided near the left and right side edges of the first plate portion 11, at positions opposite to each other. Hole H2 is provided at a position corresponding to the projection P3 of the band fixing panel 15 that is folded to the front side in the assembled state, and is configured to fit with the projection P3. Hole H3 is a through hole with a rectangular cross-section, and the left and right bands There are two mounting holes, one on each side, located between the fixing panel 15 and the hole H2. 【0036】 The holder storage panel 16 is formed in the shape of a rectangular plate with its length elongated horizontally in a plan view, and is provided on the upper edge of the first plate portion 11. More specifically, the lower edge of the holder storage panel 16 is connected to the upper edge of the first plate portion 11. The holder storage panel 16 is positioned in the center of the first plate portion 11 in the horizontal direction. As shown in Figure 2, the holder storage panel 16 is folded to the back in the assembled state. 【0037】 Here, Figure 9 is a plan view of the holder storage panel 16 as seen from the back in its unfolded state. As shown in Figure 9, a pair of guide walls 161, 161 are formed on the back surface of the holder storage panel 16 in its unfolded state, standing upright in the thickness direction and extending in the vertical direction. The pair of guide walls 161, 161 each extend along the left and right edges of the holder storage panel 16. The pair of guide walls 161, 161 extend over the entire vertical area of ​​the holder storage panel 16. A pen holder plate 9 can be placed between the pair of guide walls 161, 161. In addition, recesses 162, 163 are formed on the mutually opposing surfaces of the pair of guide walls 161, 161, recessed in the left-right direction. Recesses 162 and 163 are spaced apart in the vertical direction, with recess 162 located closer to the front end of the holder storage panel 16 than recess 163. The walls of the recesses 162 and 163 are formed in an arc shape (semicircular shape) when viewed from above. In addition, on the back surface of the holder storage panel 16 in the unfolded state, projections 164 are formed that protrude in the thickness direction from a pair of guide wall portions 161, 161. The projections 164 have a rectangular cross-section and are provided one on each side near the left and right side edges of the holder storage panel 16, at positions opposite to each other. In addition, on the back surface of the holder storage panel 16 in the unfolded state, projections 165 are formed between the pair of guide wall portions 161, 161 and protrude in the thickness direction. The projections 165 have a rectangular cross-section and are positioned in the center of the holder storage panel 16 in both the left-right and up-down directions. In addition, a slit-shaped hole H6 is formed near the base end of the holder storage panel 16, extending in the left-right direction between the pair of guide wall portions 161, 161. The hole H6 is a through hole and includes an outlet H61 extending along the upper edge of the first plate portion 11, and a window portion H62 that is connected to the central part of the outlet H61 in the left-right direction and bulges in an arc towards the front end of the holder storage panel 16. The hole H6 is wider vertically than the other parts in the window portion H62. 【0038】 As shown in Figure 8, a recess 113 is formed on the back surface S2 of the first plate portion 11, which is a rectangular shape with the length elongated in the left-right direction in a plan view. The recess 113 is a groove formed by the back surface S2 of the first plate portion 11 being recessed in the thickness direction, and is located near the base end of the holder storage panel 16. The recess 113 is provided at a position corresponding to the holder storage panel 16 that is folded to the back side in the assembled state, and is configured to fit with the holder storage panel 16. In addition, a hole H4 is formed on the bottom surface of the recess 113, drilled in the thickness direction. The hole H4 is a through hole with a rectangular cross-section, and one is provided near the left and right side edges of the recess 113, at positions opposite to each other. The hole H4 is provided at a position corresponding to the projection 164 of the holder storage panel 16 that is folded to the back side in the assembled state, and is configured to fit with the projection 164. 【0039】 Furthermore, as shown in Figure 7, a pivot groove 112 is formed near the tip (upper end) of the surface S1 of the first plate portion 11. The pivot groove 112 is formed as a groove extending in the left-right direction. In this example, one pivot groove 112 is placed on each side of the central position of the first plate portion 11 in the left-right direction, spaced apart from each other. 【0040】 Furthermore, as shown in Figure 8, protrusions P4a, P4b, P4c, P4d, P5, P6a, P6b, P6c, P6d, and P7 are formed on the back surface S2 of the board body 1, projecting in the thickness direction. It is. 【0041】 The protrusions P4a, P4b, P4c, and P4d have a rectangular cross-section and are formed on the back surface S2 of the first plate portion 11. In this example, multiple (six in this example) protrusions P4a are arranged side by side with spacing in the left-right direction, and multiple (eleven in this example) protrusions P4c are arranged side by side with spacing in the left-right direction at a position above the protrusions P4a. The protrusion P4b is located between the protrusions P4a and P4c in the vertical direction and at the center of the first plate portion 11 in the left-right direction. One protrusion P4d is provided near each of the left and right side edges of the first plate portion 11, at positions opposite to each other, and is positioned between the protrusions P4a and P4c in the vertical direction. The protrusion P5 is formed in a cylindrical shape. In this example, multiple (four in this example) protrusions P5 are arranged side by side with spacing in the left-right direction at a position between the protrusions P4a and P4c in the vertical direction. In this example, two protrusions P5 are provided on each of the left and right sides of protrusion P4b. 【0042】 The protrusions P6a, P6b, P6c, and P6d have a rectangular cross-section and are formed on the back surface S2 of the second plate portion 12. In this example, multiple (six in this example) protrusions P6a are arranged side by side with spacing in the left-right direction, and multiple (eleven in this example) protrusions P6c are arranged side by side with spacing in the left-right direction at a position lower than the protrusions P6a. The protrusion P6b is located between the protrusions P6a and P6c in the vertical direction and at the center of the second plate portion 12 in the left-right direction. One protrusion P6d is provided near the left and right side edges of the second plate portion 12, at positions opposite to each other, and is positioned between the protrusions P6a and P6c in the vertical direction. The protrusion P7 is formed in a cylindrical shape. In this example, multiple (four in this example) protrusions P7 are arranged side by side with spacing in the left-right direction at a position between the protrusions P6a and P6c in the vertical direction. In this example, two protrusions P7 are provided on each of the left and right sides of protrusion P6b. 【0043】 Furthermore, as shown in Figure 8, a rib 121 is formed on the back surface S2 of the second plate portion 12, which is erect in the thickness direction and extends in the left-right direction. The rib 121 is positioned between the projection P6c and the recess D3 in the vertical direction and extends across the entire area of ​​the second plate portion 12 in the left-right direction. 【0044】 Furthermore, a projection P8 having a rectangular cross-section and protruding in the thickness direction is formed on the back surface S2 of the second plate portion 12. One projection P8 is provided near each of the left and right side edges of the second plate portion 12, at positions opposite to each other, and is positioned between the rib 121 and the recess D3 in the vertical direction. 【0045】 Furthermore, as shown in Figures 7 and 8, a rectangular recess D1 is formed on the left edge of the hinge portion 13. The vertical width of the recess D1 is approximately the same as the vertical width of the hinge portion 13. Also, the horizontal width of the recess D1 (length in the first direction), i.e., the depth of the recess D1, is set to be greater than or equal to the slide distance, which will be described later. 【0046】 Furthermore, as shown in Figures 7 and 8, a rectangular recess D2 is formed on the upper edge of the first plate portion 11. One recess D2 is provided on each of the left and right sides of the recess 113. 【0047】 Figure 10 is a plan view of the area around the hinge portion 13 of the unfolded board body 1 as seen from the back. As shown in Figure 10, a rib 111 is formed on the back surface S2 of the first plate portion 11 near the hinge portion 13, and is erected in the thickness direction and extends in the left-right direction. The rib 111 is positioned between the projection P4a and the hinge line L1 in the vertical direction and extends across the entire area of ​​the first plate portion 11 in the left-right direction. 【0048】 Furthermore, a first locking projection 18 (an example of a "restricting portion") is provided near the hinge portion 13 on the back surface S2 of the first plate portion 11, projecting in the thickness direction. The first locking projection 18 is positioned between the rib 111 and the hinge line L1 in the vertical direction and at the center of the first plate portion 11 in the left-right direction, and is formed continuously with the lower edge of the rib 111. As shown in the enlarged view A1 of Figure 10, the first locking projection 18 has a sliding surface 181 facing the left and a restricting surface 182 facing the right. The sliding surface 181 is formed to displace to the right as it approaches the lower side (the base end side of the first plate portion 11) and is curved to be convex to the left. The restricting surface 182 is formed as a surface perpendicular to the left-right direction. 【0049】 Furthermore, as shown in Figure 10, a first engaging projection 17 (an example of a "first engaging portion") having a rectangular cross-section and projecting in the thickness direction is formed near the hinge portion 13 on the back surface S2 of the first plate portion 11. In this example, a plurality of (10 in this example) first engaging projections 17 are arranged at intervals in the left-right direction along the hinge line L1. The first engaging projections 17 are positioned between the rib 111 and the hinge line L1 in the vertical direction, and in this example, five first engaging projections 17 are provided on each side of the first locking projection 18. Note that the number of first engaging portions according to the present invention is not limited to this. There may be no multiple first engaging portions. 【0050】 Furthermore, as shown in Figure 10, a projection 131, a pair of projections 132, a biasing member holding portion 133, and a guide groove 136 are formed on the back surface S2 of the hinge portion 13. The projection 131 is a cylindrical projection that protrudes in the thickness direction and is located at the center of the hinge portion 13 in the left-right and up-down directions. The guide groove 136 is formed as a groove that extends in the left-right direction and is located at the center of the hinge portion 13 in the up-down direction, and extends over the entire area of ​​the hinge portion 13 excluding the projection 131 in the left-right direction. The pair of projections 132 consists of a pair of projections 132a, 132a that are spaced apart in the up-down direction. The pair of projections 132a, 132a are located on both the upper and lower sides of the guide groove 136. The projection 132a has a rectangular cross-section and protrudes in the thickness direction. In this example, multiple (four in this example) pairs of projections 132 are provided side by side with spacing in the left-right direction. In this example, two pairs of protrusions 132 are provided on both the left and right sides of the projection 131. The biasing member holding portion 133 is composed of a biasing member mounting groove 134 and a biasing member restricting projection 135. The biasing member mounting groove 134 is formed as a groove extending in the left-right direction. The biasing member restricting projection 135 is a projection having a rectangular cross-section and protruding in the thickness direction, and is provided adjacent to the biasing member mounting groove 134 on the right side of the biasing member mounting groove 134. In this example, multiple (four in this example) biasing member holding portions 133 are provided. In this example, two biasing member holding portions 133 are provided on both the left and right sides of the projection 131, and these two biasing member holding portions 133 are arranged on both the upper and lower sides of the guide groove 136 with a vertical gap between adjacent pairs of protrusions 132 in the left-right direction. 【0051】 [Pinch tool] As shown in Figure 1, the clamping device 10 is composed of a flap plate 2 and a leaf spring SP1. The clamping device 10 uses the biasing force of the leaf spring SP1 to clamp a piece of paper between the flap plate 2 and the surface S1 of the board body 1. Figure 11 is a plan view of the flap plate 2 as seen from the front. Figure 12 is a plan view of the flap plate 2 as seen from the back. As shown in Figures 11 and 12, the flap plate 2 is formed in a plate shape that is rectangular in shape (more specifically, a rectangle with the longer side in the left-right direction) when viewed from above. The flap plate 2 is made of a resin material such as polycarbonate, for example. However, the material of the flap plate 2 is not limited to this. The left-right width of the flap plate 2 is set to be less than or equal to the left-right width of the first plate portion 11, and the up-down width of the flap plate 2 is set to be less than or equal to the up-down width of the first plate portion 11. 【0052】 As shown in Figures 11 and 12, the flap plate 2 has holes 2 drilled in the thickness direction. A 1 is formed. Hole 21 is a through hole with a rectangular cross-section. Hole 21 is provided in the clipboard 100 at a position corresponding to the recess D2 of the first plate portion 11. In this example, two holes 21 are provided side by side with a gap between them in the left-right direction. 【0053】 As shown in Figure 12, a support rib 22 is formed on the back surface of the flap plate 2, which is erect in the thickness direction and extends in the left-right direction. The support rib 22 is located near the center of the flap plate 2 in the vertical direction and is positioned below the hole 21. The support rib 22 is provided in the clipboard 100 at a position corresponding to the support groove 112 of the first plate portion 11. In this example, one support rib 22 is placed on each side of the central position of the hole 21 in the left-right direction, spaced apart from each other. The support rib 22 is configured to be received by the support groove 112 in the clipboard 100. 【0054】 Furthermore, a projection 23 having a rectangular cross-section and protruding in the thickness direction is formed on the back surface of the flap plate 2. The projection 23 is positioned below the support rib 22 in the vertical direction, and in this example, multiple projections 23 (five in this example) are arranged side by side with spacing between them in the left-right direction. 【0055】 As shown in Figure 5, the leaf spring SP1 is formed as a U-shaped metal leaf spring. The clamping device 10 in this example has two leaf springs SP1. One leaf spring SP1 is attached to each recess D2 of the board body 1. 【0056】 Figure 13 is a cross-sectional view of Figure 1, AA. As shown in Figure 13, the clamping device 10 is attached to the board body 1 by clamping the board body 1 and the flap plate 2 with a leaf spring SP1. 【0057】 As shown in Figure 13, in the clipboard 100, the flap plate 2 is placed on the board body 1 from the front side such that the pivot rib 22 of the flap plate 2 is housed in the pivot groove 112 of the first plate portion 11. This allows the flap plate 2 to rotate around the pivot rib 22 as a pivot point. One end of the leaf spring SP1, inserted into the recess D2, passes through the pivot rib 22 from the back side of the flap plate 2 and contacts the pivot rib 22 from the front side, while the other end of the leaf spring SP1 contacts the first plate portion 11 from the back side. This one end of the leaf spring SP1 extends to a position below the pivot rib 22. The flap plate 2 is biased by the elastic force of the leaf spring SP1 such that the projection 23 located below the pivot rib 22 is pressed against the surface S1 of the first plate portion 11. Therefore, the portion of the flap plate 2 above the pivot rib 22 is spaced apart from the board body 1 in the thickness direction. When the user of the clipboard 100 (hereinafter sometimes simply referred to as "user") pushes the upper end of the flap plate 2 toward the board body 1 against the biasing force of the leaf spring SP1, the flap plate 2 rotates around the pivot rib 22 as a pivot point, causing the projection 23 to separate from the first plate portion 11, creating a gap between the projection 23 and the surface S1 of the first plate portion 11. This allows a piece of paper to be inserted between the projection 23 and the first plate portion 11. When the user releases the pressure on the upper end of the flap plate 2 with a piece of paper inserted between the projection 23 and the first plate portion 11, the biasing force of the leaf spring SP1 causes the projection 23 to press the piece of paper toward the surface S1 of the first plate portion 11. As a result, the clipping device 10 can hold the piece of paper between the flap plate 2 and the board body 1. In this example, the clamping device 10 is provided on the surface S1 of the first plate portion 11, but the present invention is not limited to this. The clamping device may also be provided on the back surface of the board body. Furthermore, the clamping device may be provided on either the first plate portion or the second plate portion, or it may be provided on the second plate portion. 【0058】 [First cover plate (first retaining member)] As shown in Figure 2, the first cover plate 4 is a plate member that extends in the left-right direction, and the first The first cover plate 4 is attached to the back surface S2 of the board portion 11. The first cover plate 4 holds the cover sheet 6 so that it can slide in the second direction. Figure 14 is a plan view of the first cover plate 4 as seen from the front. Figure 15 is a plan view of the first cover plate 4 as seen from the back. The first cover plate 4 is attached to the first board portion 11 such that the surface visible in Figure 14 faces the back surface S2 of the board body 1. As shown in Figures 14 and 15, the first cover plate 4 is formed in a plate shape that is rectangular in shape (more specifically, a rectangle with the longer side in the left-right direction) when viewed from above. The first cover plate 4 is made of a resin material such as polycarbonate, for example. However, the material of the first cover plate 4 is not limited to this. The left-right width of the first cover plate 4 is smaller than the left-right width of the first board portion 11, and the up-down width of the first cover plate 4 is smaller than the up-down width of the first board portion 11. 【0059】 As shown in Figures 14 and 15, a hole 41, which is a through-hole with a rectangular cross-section drilled in the thickness direction, is formed at the center of the first cover plate 4 in the left-right and up-down directions. The hole 41 is provided in the clipboard 100 at a position corresponding to the projection P4b of the first plate portion 11 and is configured to engage with the projection P4b. 【0060】 Furthermore, a hole 43, which is a through-hole with a rectangular cross-section drilled in the thickness direction, is formed near the upper edge of the first cover plate 4. The hole 43 is provided in the clipboard 100 at a position corresponding to the projection P4c of the first plate portion 11, and is configured to engage with the projection P4c. In this example, multiple (11 in this example) holes 43 are provided side by side along the upper edge of the first cover plate 4, spaced apart in the left-right direction. 【0061】 Furthermore, as shown in Figure 14, cylindrical protrusions 42 projecting in the thickness direction are formed on the surface of the first cover plate 4 facing the back surface S2 of the board body 1 in the clipboard 100. The protrusions 42 are provided in the clipboard 100 at positions corresponding to the protrusions P5 of the first plate portion 11 and are configured to engage with the protrusions P5. In this example, multiple (four in this example) protrusions 42 are provided at the center of the first cover plate 4 in the vertical direction, spaced apart in the left-right direction. In this example, two protrusions 42 are provided on each side of the hole 41. 【0062】 As shown in Figures 14 and 15, a corrugated hole 44 is formed near the lower edge of the first cover plate 4, penetrating the first cover plate 4 in the thickness direction. The corrugated hole 44 is formed in a rectangular wave shape with repeated vertical indentations and convexities that continue in the left-right direction, and extends across the entire left and right area of ​​the first cover plate 4, except for the left and right ends of the first cover plate 4. By forming the corrugated hole 44 near the lower edge of the first cover plate 4, the lower edge of the first cover plate 4 forms a flexible fixing piece 45. The fixing piece 45 is the part of the first cover plate 4 adjacent to the lower side of the corrugated hole 44 in the vertical direction, and is more flexible in the thickness direction compared to other parts of the first cover plate 4. Here, the part of the fixing piece 45 defined by the upwardly convex wave in the corrugated hole 44 is called the wide part 45a. The wide part 45a is convex upward and has a wider vertical width than other parts of the fixing piece 45. 【0063】 Furthermore, a hole 46, which is a through-hole with a rectangular cross-section drilled in the thickness direction, is formed in the wide portion 45a of the fixing piece 45. The hole 46 is provided in the clipboard 100 at a position corresponding to the projection P4a of the first plate portion 11, and is configured to engage with the projection P4a. In this example, multiple (six in this example) holes 46 are provided side by side with spacing between them in the left-right direction. 【0064】 Furthermore, as the corrugated holes 44 are formed, the portion of the first cover plate 4 above the corrugated holes 44 is defined by the downwardly convex corrugation of the corrugated holes 44, forming a retaining piece 47. A structure is formed. The retaining piece 47 is convex downwards. 【0065】 Furthermore, as shown in Figures 14 and 15, rectangular recesses D4 are formed on the left and right side edges of the first cover plate 4. The recesses D4 are provided in the clipboard 100 at positions corresponding to the projections P4d of the first plate portion 11, and are configured to engage with the projections P4d. 【0066】 The first cover plate 4 is attached to the back surface S2 of the first plate portion 11 by the fact that hole 41 engages with projection P4b, projection 42 engages with projection P5, hole 43 engages with projection P4c, hole 46 engages with projection P4a, and recess D4 engages with projection P4d (see Figure 22). 【0067】 [Second cover plate (second retaining member)] As shown in Figure 2, the second cover plate 5 is a plate member extending in the left-right direction and is attached to the back surface S2 of the second plate portion 12. The second cover plate 5 engages with the slide member 3 and holds the cover sheet 6 so that it can slide in the second direction. Figure 16 is a plan view of the second cover plate 5 as seen from the front side. Figure 17 is a plan view of the second cover plate 5 as seen from the back side. The second cover plate 5 is attached to the second plate portion 12 such that the surface visible in Figure 16 faces the back surface S2 of the board body 1. As shown in Figures 16 and 17, the second cover plate 5 is formed in a plate shape that is rectangular in shape (more specifically, a rectangle with the longer side in the left-right direction) when viewed in plan. The second cover plate 5 is made of a resin material such as polycarbonate. However, the material of the second cover plate 5 is not limited to this. The width of the second cover plate 5 is smaller than the width of the second plate portion 12, and the height of the second cover plate 5 is smaller than the height of the second plate portion 12. 【0068】 As shown in Figures 16 and 17, a hole 51, which is a through-hole with a rectangular cross-section drilled in the thickness direction, is formed at the center of the second cover plate 5 in the left-right and up-down directions. The hole 51 is provided in the clipboard 100 at a position corresponding to the projection P6b of the second plate portion 12 and is configured to engage with the projection P6b. 【0069】 Furthermore, a hole 53, which is a through-hole with a rectangular cross-section drilled in the thickness direction, is formed near the lower edge of the second cover plate 5. The hole 53 is provided in the clipboard 100 at a position corresponding to the projection P6c of the second plate portion 12, and is configured to engage with the projection P6c. In this example, multiple (11 in this example) holes 53 are provided side by side along the lower edge of the second cover plate 5, spaced apart in the left-right direction. 【0070】 Furthermore, as shown in Figure 16, cylindrical protrusions 52 projecting in the thickness direction are formed on the surface of the second cover plate 5 facing the back surface S2 of the board body 1 in the clipboard 100. The protrusions 52 are provided in the clipboard 100 at positions corresponding to the protrusions P7 of the second plate portion 12 and are configured to engage with the protrusions P7. In this example, multiple (four in this example) protrusions 52 are provided at the center of the second cover plate 5 in the vertical direction, spaced apart in the left-right direction. In this example, two protrusions 52 are provided on each side of the hole 51. 【0071】 Here, as shown in Figures 16 and 17, a corrugated hole 54 is formed near the upper edge of the second cover plate 5, penetrating the second cover plate 5 in the thickness direction. The corrugated hole 54 is formed in a rectangular wave shape with repeated vertical indentations and continuities in the left-right direction, and extends across the entire left and right area of ​​the second cover plate 5, except for the left and right ends of the second cover plate 5. By forming the corrugated hole 54 near the upper edge of the second cover plate 5, the upper edge of the second cover plate 5 forms a flexible fixing piece 55. The fixing piece 55 is the portion of the second cover plate 5 adjacent to the upper side of the corrugated hole 54 in the vertical direction, and the second cover plate 5 It is more flexible in the thickness direction compared to other parts. Here, the part of the fixing piece 55 defined by the downwardly convex wave in the corrugated hole 54 is defined as the wide part 55a. The wide part 55a is convex downward and has a wider vertical width than other parts of the fixing piece 55. 【0072】 Furthermore, a hole 56, which is a through-hole with a rectangular cross-section drilled in the thickness direction, is formed in the wide portion 55a of the fixing piece 55. The hole 56 is provided in the clipboard 100 at a position corresponding to the projection P6a of the second plate portion 12, and is configured to engage with the projection P6a. In this example, multiple (six in this example) holes 56 are provided side by side with spacing between them in the left-right direction. 【0073】 Furthermore, as the corrugated holes 54 are formed, a retaining piece 58 is formed on the portion of the second cover plate 5 below the corrugated holes 54, defined by the upwardly convex waveform in the corrugated holes 54. The retaining piece 58 is convex upward. 【0074】 Furthermore, as shown in Figures 16 and 17, rectangular recesses D5 are formed on the left and right side edges of the second cover plate 5. The recesses D5 are provided in the clipboard 100 at positions corresponding to the projections P6d of the second plate portion 12, and are configured to engage with the projections P6d. 【0075】 Furthermore, as shown in Figure 17, a second locking projection 59 (an example of a "restricting portion") protruding in the thickness direction is provided near the upper edge of the back surface of the second cover plate 5. The second locking projection 59 is positioned in the center of the second cover plate 5 in the left-right direction. As shown in the enlarged view of A2 in Figure 17, the second locking projection 59 has a sliding surface 591 facing the left and a restricting surface 592 facing the right. The sliding surface 591 is formed to displace to the right as it approaches the upper side (the base end side of the second plate portion 12 in the clipboard 100), and is curved to be convex to the left. The restricting surface 592 is formed as a surface perpendicular to the left-right direction. 【0076】 Furthermore, as shown in Figure 17, a second engaging projection 57 (an example of a "second engaging portion") having a rectangular cross-section and protruding in the thickness direction is formed near the upper edge of the back surface of the second cover plate 5. In this example, a plurality of (10 in this example) second engaging projections 57 are arranged at intervals in the left-right direction along the upper edge of the second cover plate 5. Five second engaging projections 57 are provided on each side of the second locking projection 59. Note that the number of second engaging portions according to the present invention is not limited to this. There may be no plurality of second engaging portions. 【0077】 The second cover plate 5 is attached to the back surface S2 of the second plate portion 12 by the fact that hole 51 engages with projection P6b, projection 52 engages with projection P7, hole 53 engages with projection P6c, hole 56 engages with projection P6a, and recess D5 engages with projection P6d (see Figure 22). 【0078】 [Sliding component] As shown in Figures 2 and 3, the slide member 3 is a plate member extending in the left-right direction and is attached to the back surface S2 of the hinge portion 13 so that it can slide along the left-right direction, as will be described later. Figure 18 is a plan view of the slide member 3 as seen from the front. Figure 19 is a plan view of the slide member 3 as seen from the back. Figure 20 is a cross-sectional view BB of Figure 18, and Figure 21 is a cross-sectional view CC of Figure 18. The slide member 3 is attached to the hinge portion 13 so that the surface visible in Figure 18 faces the back surface S2 of the board body 1. As shown in Figures 18 and 19, the slide member 3 is formed in a plate shape that is rectangular in plan view (more specifically, a rectangle with the longer side in the left-right direction). The slide member 3 is made of a resin material such as polycarbonate. However, the slide member 3 The materials are not limited to these. The left-right width of the slide member 3 is smaller than the left-right width of the hinge portion 13, and the up-down width of the slide member 3 is larger than the up-down width of the hinge portion 13. 【0079】 As shown in Figures 18 and 19, the slide member 3 is formed symmetrically from top to bottom. The slide member 3 has a biasing member guide hole 35, a slide restricting hole 37, and a projection guide hole 38. The biasing member guide hole 35, the slide restricting hole 37, and the projection guide hole 38 are formed as through holes drilled in the thickness direction. 【0080】 The projection guide hole 38 is an elongated hole extending in the left-right direction and is positioned at the center of the slide member 3 in both the left-right and up-down directions. The projection guide hole 38 is provided in the clipboard 100 at a position corresponding to the projection 131 of the hinge portion 13 and is configured to receive the projection 131. The left-right width of the projection guide hole 38 is set to be greater than or equal to the sliding distance of the slide member 3. 【0081】 Furthermore, the slide restricting holes 37 are through holes with a rectangular cross-section that is elongated in the left-right direction. In this example, multiple (four in this example) slide restricting holes 37 are provided at intervals in the left-right direction at the central position of the slide member 3 in the vertical direction. In this example, two slide restricting holes 37 are provided on each side of the projection guide hole 38. The slide restricting holes 37 are provided in the clipboard 100 at positions corresponding to the projection pair 132 of the hinge portion 13, and are configured to receive the projection pair 132. The left-right width of the slide restricting holes 37 is set to be greater than or equal to the slide distance of the slide member 3. 【0082】 Here, as shown in Figure 18, on the surface of the slide member 3 facing the back surface S2 of the board body 1 in the clipboard 100, a slide rib 39 is formed that is erect in the thickness direction and extends in the left-right direction. The slide rib 39 is positioned at the center of the slide member 3 in the vertical direction and extends across the entire area of ​​the slide member 3 in the left-right direction, excluding the slide restricting hole 37 and the projection guide hole 38. The slide rib 39 is provided in the clipboard 100 at a position corresponding to the guide groove 136 of the hinge portion 13 and is received by the guide groove 136. 【0083】 Furthermore, the biasing member guide hole 35 includes a biasing member housing portion 351 extending in the left-right direction, and a projection housing portion 352 provided to the right of the biasing member housing portion 351, connected to the biasing member housing portion 351 and extending in the left-right direction. The biasing member housing portion 351 and the projection housing portion 352 are formed as through holes with a rectangular cross-section that is longitudinal in the left-right direction. The vertical width of the biasing member housing portion 351 is set to be greater than or equal to the width (vertical width) of the compression spring SP2. The vertical width of the projection housing portion 352 is set to be greater than or equal to the vertical width of the biasing member regulating projection 135 and less than the width (vertical width) of the compression spring SP2. In addition, the left-right width of the biasing member guide hole 35 is set to be greater than or equal to the sliding distance of the slide member 3. This biasing member guide hole 35 is provided in the clipboard 100 at a position corresponding to the biasing member holding portion 133 of the hinge portion 13. In this example, multiple (four in this example) biasing member guide holes 35 are provided. In this example, two biasing member guide holes 35 are provided on both the left and right sides of the projection guide hole 38. These two biasing member guide holes 35 are positioned on the upper and lower sides of the slide rib 39, spaced vertically between adjacent slide restricting holes 37 in the left-right direction. The biasing member housing section 351 is configured to house the compression spring SP2 placed on the biasing member mounting groove 134, and the projection housing section 352 is configured to receive the biasing member restricting projection 135. 【0084】 Furthermore, a biasing member mounting projection 36 is formed at the left end of the biasing member guide hole 35, that is, at the left edge of the biasing member housing portion 351. The biasing member mounting projection 36 is a projection that protrudes to the right from the left edge of the biasing member housing portion 351, and is configured to allow the end (left end) of the compression spring SP2 to be attached. It has been done. 【0085】 As shown in Figures 18 and 19, slit holes 3a are formed near the upper and lower edges of the slide member 3 at the left-right center, penetrating the slide member 3 in the thickness direction. One slit hole 3a is provided on each side of the projection guide hole 38 in the vertical direction. The slit holes 3a extend in the left-right direction along the upper and lower edges of the slide member 3, and both ends in the left-right direction are bent inward (towards the center) in the vertical direction. By forming slit holes 3a near the upper and lower edges of the slide member 3, the upper and lower edges at the left-right center of the slide member 3 each form a flexible elastic piece 33. The elastic piece 33 is the part of the slide member 3 adjacent to the outside of the slit holes 3a in the vertical direction, and is more flexible in the vertical direction compared to other parts of the slide member 3. 【0086】 Furthermore, the elastic piece 33 has a contact projection 34 (contact portion) that protrudes outward (away from the center) in the vertical direction. As shown in the enlarged view of A3 in Figure 18, the contact projection 34 has a sliding surface 341 facing left and a restricting surface 342 facing right. The sliding surface 341 is formed to displace to the right as it moves outward in the vertical direction and is curved to be convex to the left. The restricting surface 342 is formed as a surface perpendicular to the left-right direction. 【0087】 Hereinafter, of the pair of elastic pieces 33, 33 formed on the upper and lower edges of the slide member 3, the upper elastic piece 33 may be referred to as the first elastic piece 33U, and the lower elastic piece 33 may be referred to as the second elastic piece 33L. Furthermore, the contact projection 34 formed on the first elastic piece 33U may be referred to as the first contact projection 34U, and the contact projection 34 formed on the second elastic piece 33L may be referred to as the second contact projection 34L. 【0088】 Furthermore, as shown in Figure 18, on the surface of the slide member 3 facing the back surface S2 of the board body 1 in the clipboard 100, a first engagement hole 31 (an example of a "first locking part") and a second engagement hole 32 (an example of a "second locking part") are formed, which are non-through holes drilled in the thickness direction. The first engagement hole 31 and the second engagement hole 32 are located opposite each other in the vertical direction, with the slide rib 39 in between. 【0089】 The first engagement hole 31 is provided in the clipboard 100 at a position corresponding to the first engagement projection 17 of the board body 1, and is configured to receive the first engagement projection 17. In this example, a plurality of (10 in this example) first engagement holes 31 are provided side by side along the upper edge of the slide member 3, spaced apart in the left-right direction. In this example, five first engagement holes 31 are provided on each side of the first elastic piece 33U. Note that the number of first locking parts according to the present invention is not limited to this. There may be no plurality of first locking parts. 【0090】 As shown in Figure 18, the first engagement hole 31 includes a release portion 311 extending in the left-right direction and a fixing portion 312 provided to the right of the release portion 311, which is connected to the release portion 311 and also extends in the left-right direction. The release portion 311 and the fixing portion 312 have different vertical widths, with the release portion 311 having a larger opening width than the fixing portion 312. The left-right width of the first engagement hole 31 is set to be greater than or equal to the sliding distance of the slide member 3. Furthermore, the left-right width of the release portion 311 and the left-right width of the fixing portion 312 are set to be less than the sliding distance of the slide member 3. 【0091】 The second engagement hole 32 is provided in the clipboard 100 at a position corresponding to the second engagement projection 57 of the second cover plate 5, and is configured to receive the second engagement projection 57. In this example, a plurality of (10 in this example) second engagement holes 32 are provided side by side along the lower edge of the slide member 3, spaced apart in the left-right direction. In this example, the second elastic piece 33L Five second engagement holes 32 are provided on each of the left and right sides. However, the number of second locking parts according to the present invention is not limited to this. There may be no multiple second locking parts. 【0092】 As shown in Figure 18, the second engagement hole 32 includes a release portion 321 extending in the left-right direction and a fixing portion 322 provided to the right of the release portion 321, which is connected to the release portion 321 and also extends in the left-right direction. The fixing portion 322 and the release portion 321 have different opening widths (vertical widths), with the release portion 321 having a larger opening width than the fixing portion 322. The left-right width of the second engagement hole 32 is set to be greater than or equal to the sliding distance of the slide member 3. In addition, the left-right width of the fixing portion 322 and the left-right width of the release portion 321 are set to be less than the sliding distance of the slide member 3. 【0093】 [Fixing means] As shown in Figure 6, the fixing means 20 is provided on the back surface S2 of the board body 1, and can fix the board body 1 in a base plate state. The fixing means 20 is composed of a slide member 3 attached to the hinge portion 13, a first engaging projection 17 provided on the first plate portion 11, a second engaging projection 57 provided on the second plate portion 12 (more specifically, provided on the second cover plate 5 attached to the second plate portion 12), and a compression spring SP2 that biases the slide member 3. 【0094】 Figures 22 and 23 are plan views of the area around the fixing means 20 of the flat clipboard 100 as seen from the back. Figure 22 shows the slide member 3 in the first position, and Figure 23 shows the slide member 3 in the second position. For convenience, the cover sheet 6 and fixing plate 7 are omitted from the illustration in Figures 22 and 23. 【0095】 As shown in Figures 22 and 23, the fixing means 20 is configured to allow the slide member 3 to be displaced along the first direction (left-right direction) within a range including a first position and a second position that are separated from each other in the first direction (left-right direction). When the slide member 3 is in the first position, the board body 1 is fixed to the base plate state, and when the slide member 3 is in the second position, the fixing is released. Specifically, when the board body 1 is in the base plate state, the slide member 3 slides from the first position to the second position, releasing the fixing of the board body 1 by the fixing means 20. This allows the first plate portion 11 and the second plate portion 12 to rotate around the hinge portion 13, making it possible to switch the board body 1 from the base plate state to the folded state. Hereinafter, the direction from the first position to the second position in the first direction may be referred to as the "release direction," and the opposite direction, that is, the direction from the second position to the first position, may be referred to as the "lock direction." As shown in Figures 22 and 23, in this example, the second position is to the right of the first position. Therefore, in this example, the "right side" in the left-right direction corresponds to the "release direction," and the "left side" corresponds to the "lock direction." The distance between the first position and the second position in the first direction (left-right direction) is called the "slide distance" and is denoted by d1. In this example, the slide member 3 is slidable within the range of the slide distance d1. However, the present invention is not limited thereto, and the locking member may be displaceable in a range exceeding the distance between the first position and the second position in the first direction. 【0096】 As shown in Figures 22 and 23, in the clipboard 100, the biasing member restricting projection 135 is received in the biasing member guide hole 35, the pair of projections 132 is received in the slide restricting hole 37, the projection 131 is received in the projection guide hole 38, and the slide rib 39 is received in the guide groove 136. In this state, as will be described later, the fixing plate 7 is attached to the hinge portion 13, so that the slide member 3 is attached to the hinge portion 13 in a state that allows it to slide along the left-right direction. The projection 131, the pair of projections 132, the biasing member restricting projection 135, and the guide groove 136 restrict the movement of the slide member 3 in the second direction (up and down direction) while allowing movement in the first direction (left and right direction). 【0097】 Furthermore, the biasing member housing portion 351 of the slide member 3 houses the compression spring SP2, which is placed in the biasing member mounting groove 134 of the hinge portion 13. The compression spring SP2 is a metal elastic member formed as a so-called coil spring, and is positioned so that its longitudinal direction (extension direction) coincides with the first direction (left-right direction), which is the displacement direction of the slide member 3. The left end of the compression spring SP2 is attached to the biasing member mounting projection 36. The compression spring SP2 is positioned to the left of the biasing member regulating projection 135 (towards the locking direction). More specifically, in the first direction, the compression spring SP2 is positioned between the left edge of the biasing member housing portion 351 and the biasing member regulating projection 135. 【0098】 As shown in Figures 22 and 23, in the clipboard 100 in its base plate state, the first engaging projection 17 provided on the first plate portion 11 is received in the first engaging hole 31 of the slide member 3, and the second engaging projection 57 provided on the second plate portion 12 is received in the second engaging hole 32 of the slide member 3. As shown in Figure 22, when the board body 1 is in the base plate state and the slide member 3 is in the first position, the first engaging projection 17 fits into the fixing portion 312 and the second engaging projection 57 fits into the fixing portion 322, thereby fixing the board body 1 in the base plate state. On the other hand, as shown in Figure 23, when the slide member 3 is moved from the first position to the second position by a sliding operation, the first engaging projection 17 is housed in the release portion 311 and the second engaging projection 57 is housed in the release portion 321, thereby releasing the board body 1 from being fixed in the base plate state. The operation of the fixing means 20 will be described below. 【0099】 As shown in Figure 22, when the board body 1 is in the base plate state and the slide member 3 is in the first position, the left edge of the slide member 3 is aligned with the left edge of the board body 1, and the right edge of the slide member 3 is located to the left of the right edge of the board body 1. In this state, the first engaging projection 17 of the first plate portion 11 is located within the fixing portion 312 of the first engaging hole 31, and the second engaging projection 57 of the second plate portion 12 is located within the fixing portion 322 of the second engaging hole 32. The biasing member regulating projection 135 of the hinge portion 13 is located within the projection housing portion 352 of the biasing member guide hole 35. The first contact projection 34U of the slide member 3 is located to the left of the first locking projection 18 of the first plate portion 11, and the second contact projection 34L is located to the left of the second locking projection 59 of the second plate portion 12. In this state, the projection 131 abuts against the right edge of the projection guide hole 38, and the pair of projections 132 to the right of projection 131 abuts against the right edge of the slide restricting hole 37, thereby restricting the movement of the slide member 3 in the locking direction. 【0100】 Figure 24 is a schematic cross-sectional view showing the DD cross section of Figure 22. In Figure 24, a cross section perpendicular to the first direction (left-right direction) is shown. Here, as shown in Figure 24, with respect to the rotation direction of the first plate portion 11 and the second plate portion 12 around the hinge portion 13, the direction in which the first plate portion 11 and the second plate portion 12 rotate relative to the hinge portion 13 so that the board body 1 moves from the base plate state to the folded state is called the "folding direction," and the opposite direction, that is, the direction in which the first plate portion 11 and the second plate portion 12 rotate relative to the hinge portion 13 so that the board body 1 moves from the folded state to the base plate state, is called the "unfolding direction." More specifically, the "folding direction" and the "unfolding direction" are the rotation directions around the hinge line L1 for the first plate portion 11 and around the hinge line L2 for the second plate portion 12. 【0101】 Here, as shown in Figure 24, the upper surface of the first engaging projection 17 is referred to as the folding direction surface 17a, and the lower surface of the first engaging projection 17 is referred to as the unfolding direction surface 17b. Similarly, the lower surface of the second engaging projection 57 is referred to as the folding direction surface 57a, and the upper surface of the second engaging projection 57 is referred to as the unfolding direction surface 57b. The folding direction surfaces 17a and 57a face the folding direction and are perpendicular to the vertical direction in the base plate state. The unfolding direction surfaces 17b and 57b face the unfolding direction and are perpendicular to the vertical direction in the base plate state. Furthermore, the inner wall of the first engaging hole 31 is referred to as the locking wall W31, and the inner wall of the second engaging hole 32 is referred to as the locking wall W32. 【0102】 As shown in Figure 24, when the board body 1 is in the base plate state and the slide member 3 is in the first position, the first engaging projection 17 of the first plate portion 11 is located within the fixing portion 312 of the first engaging hole 31. The opening width of the fixing portion 312 is set such that the first engaging projection 17 is prevented from disengaging from the first engaging hole 31 when the slide member 3 is in the second position. Specifically, the locking wall W31 abuts against the unfolding direction surface 17b of the first engaging projection 17 from the unfolding direction. This prevents the first plate portion 11 from rotating in the unfolding direction. Furthermore, the locking wall W31 abuts against the folding direction surface 17a of the first engaging projection 17 from the folding direction. This prevents the first plate portion 11 from rotating in the folding direction. 【0103】 Similarly, as shown in Figure 24, when the board body 1 is in the base plate state and the slide member 3 is in the first position, the second engaging projection 57 of the second plate portion 12 is located within the fixing portion 322 of the second engaging hole 32. The opening width of the fixing portion 322 is set such that the second engaging projection 57 is prevented from disengaging from the second engaging hole 32 when the slide member 3 is in the second position. Specifically, the locking wall W32 abuts against the unfolding direction surface 57b of the second engaging projection 57 from the unfolding direction. This prevents the second plate portion 12 from rotating in the unfolding direction. Furthermore, the locking wall W32 abuts against the folding direction surface 57a of the second engaging projection 57 from the folding direction. This prevents the second plate portion 12 from rotating in the folding direction when the board body 1 is in the base plate state and the slide member 3 is in the first position. 【0104】 As described above, when the board body 1 is in the base plate state and the slide member 3 is in the first position, the first engagement hole 31 of the slide member 3 engages with the first engagement projection 17 of the first plate portion 11, and the second engagement hole 32 of the slide member 3 engages with the second engagement projection 57 of the second plate portion 12, thereby restricting the rotation of the first plate portion 11 and the second plate portion 12 in the unfolding direction and the rotation in the folding direction. As a result, the board body 1 is fixed in the base plate state. 【0105】 With the board body 1 in the base plate state and the slide member 3 in the first position, the slide member 3 can be moved to the second position by a sliding operation in the release direction, thereby releasing the fixation of the slide member 3 to the base plate state. Here, the sliding operation of the slide member 3 in the release direction can be performed by pushing the left edge of the slide member 3 in the release direction with the user's finger. At this time, as shown in Figure 22, a recess D1 having a depth greater than the sliding distance is formed on the left edge of the hinge portion 13. Therefore, when pushing the slide member 3 in the release direction from the first position to the second position, contact between the user's finger and the left edge of the hinge portion 13 is suppressed. As a result, the user can slide the slide member 3 to the second position without being hindered by the side edge of the hinge portion 13, making the sliding operation easier. 【0106】 With the board body 1 in a base plate state and the slide member 3 in the first position, when the slide member 3 is moved relative to the board body 1 in the release direction by a sliding operation, the first engaging projection 17 moves relative to the left within the first engaging hole 31, and the second engaging projection 57 moves relative to the left within the second engaging hole 32. Similarly, projection 131 moves relative to the left within projection guide hole 38, projection pair 132 moves relative to the left within slide restricting hole 37, biasing member restricting projection 135 moves relative to the left within biasing member guide hole 35, and guide groove 136 moves relative to the left along slide rib 39. Then, as shown in Figure 23, when the slide member 3 reaches the second position, projection 131 abuts against the left edge of projection guide hole 38, and projection pair 132 to the left of projection 131 abuts against the left edge of slide restricting hole 37, thereby restricting further movement of the slide member 3 in the release direction, and the slide member 3 stops at the second position. 【0107】 As shown in Figure 23, the board body 1 is in the base plate position and the sliding member 3 is in the second position. In this configuration, the first engaging projection 17 of the first plate portion 11 is located within the release portion 311 of the first engaging hole 31, and the second engaging projection 57 of the second plate portion 12 is located within the release portion 321 of the second engaging hole 32. Also, the biasing member regulating projection 135 of the hinge portion 13 is located within the biasing member housing portion 351 of the biasing member guide hole 35. Furthermore, the first contact projection 34U of the slide member 3 is located to the right of the first locking projection 18 of the first plate portion 11, and the second contact projection 34L is located to the right of the second locking projection 59 of the second plate portion 12. 【0108】 In this process, as the sliding member 3 moves from the first position to the second position, the first contact projection 34U moves over the first locking projection 18 of the first plate portion 11 and is positioned to the right of the first locking projection 18U, and the second contact projection 34L moves over the second locking projection 59 of the second plate portion 12 and is positioned to the right of the second locking projection 59. 【0109】 Figure 25 shows the area near the contact projection 34 when the board body 1 is in the base plate state and the slide member 3 is in the first position. As shown in Figure 25, when the board body 1 is in the base plate state and the slide member 3 is in the first position, the sliding surface 341 of the first contact projection 34U and the sliding surface 181 of the first locking projection 18 face each other in the first direction. The sliding surface 341 of the first contact projection 34U and the sliding surface 181 of the first locking projection 18 are formed to displace in the release direction as they approach each other in the second direction (vertical direction). Therefore, as the slide member 3 moves relative to each other in the release direction, the sliding surface 341 of the first contact projection 34U slides against the sliding surface 181 of the first locking projection 18, and the first elastic piece 33U bends and displaces downward, causing the first contact projection 34U to overcome the first locking projection 18 and reach the right side (forward side in the release direction) of the first locking projection 18. Similarly, when the board body 1 is in a base plate state and the slide member 3 is in the first position, the sliding surface 341 of the second contact projection 34L and the sliding surface 591 of the second locking projection 59 face each other in the first direction. The sliding surface 341 of the second contact projection 34L and the sliding surface 591 of the second locking projection 59 are formed to displace in the release direction as they approach each other in the second direction (vertical direction). Therefore, as the slide member 3 moves relative to each other in the release direction, the sliding surface 341 of the second contact projection 34L slides against the sliding surface 591 of the second locking projection 59, and the second elastic piece 33L bends and displaces upward, causing the second contact projection 34L to overcome the second locking projection 59 and reach the right side (forward side in the release direction) of the second locking projection 59. 【0110】 Figure 26 shows the area near the contact projection 34 when the board body 1 is in the base plate state and the slide member 3 is in the second position. As shown in Figure 26, when the board body 1 is in the base plate state and the slide member 3 is in the second position, the restricting surface 342 of the first contact projection 34U and the restricting surface 182 of the first locking projection 18 face each other in the first direction, and the restricting surface 182 of the first locking projection 18 abuts against the restricting surface 342 of the first contact projection 34U from the locking direction. Here, since both the restricting surface 342 of the first contact projection 34U and the restricting surface 182 of the first locking projection 18 are formed to be perpendicular to the first direction (left-right direction), the first contact projection 34U is prevented from going over the first locking projection 18 and reaching the left side of the first locking projection 18 (the leading side in the locking direction). As a result, the first locking projection 18 engages with the slide member 3. Similarly, when the board body 1 is in the base plate state and the slide member 3 is in the second position, the restricting surface 342 of the second contact projection 34L and the restricting surface 592 of the second locking projection 59 face each other in the first direction, and the restricting surface 592 of the second locking projection 59 abuts against the restricting surface 342 of the second contact projection 34L from the locking direction. Here, since both the restricting surface 342 of the second contact projection 34L and the restricting surface 592 of the second locking projection 59 are formed to be perpendicular to the first direction (left-right direction), the second contact projection 34L is prevented from going over the second locking projection 59 and reaching the left side of the second locking projection 59 (the leading side in the locking direction). As a result, the second locking projection 59 engages with the slide member 3. 【0111】 As described above, when the board body 1 is in the base plate state and the slide member 3 is in the second position, the first locking projection 18 and the second locking projection 59 come into contact with the slide member 3 from the locking direction. The first locking projection 18 and the second locking projection 59 engage with the slide member 3 so that they are in contact with each other, thereby restricting the relative movement of the slide member 3 in the locking direction (opposite to the release direction). In other words, the movement of the slide member 3 to the first position is restricted by the first locking projection 18 and the second locking projection 59. 【0112】 Here, as shown in Figure 23, when the board body 1 is in the base plate state and the slide member 3 is in the second position, the biasing member regulating projection 135 of the hinge portion 13 enters the biasing member housing portion 351 of the biasing member guide hole 35, and the compression spring SP2 housed in the biasing member housing portion 351 is squeezed between the left edge of the biasing member housing portion 351 and the biasing member regulating projection 135, and compressed in the first direction. As a result, the slide member 3 is biased in the locking direction by the restoring force (elastic force) of the compression spring SP2. However, as described above, when the board body 1 is in the base plate state and the slide member 3 is in the second position, the first locking projection 18 and the second locking projection 59 engage with the slide member 3, thereby restricting the relative movement of the slide member 3 in the locking direction. Therefore, when the board body 1 is in the base plate state and the sliding member 3 is in the second position, the state is maintained in which the first engaging projection 17 of the first plate portion 11 is located within the release portion 311 of the first engaging hole 31 and the second engaging projection 57 of the second plate portion 12 is located within the release portion 321 of the second engaging hole 32. 【0113】 Figure 27 is a schematic cross-sectional view showing the EE section of Figure 23. In Figure 27, a cross-section perpendicular to the first direction (left-right direction) is shown, corresponding to the cross-section in Figure 24. As shown in Figure 27, when the board body 1 is in the base plate state and the slide member 3 is in the second position, the first engaging projection 17 of the first plate portion 11 is located within the release portion 311 of the first engaging hole 31. The opening width of the release portion 311 is set such that the first engaging projection 17 can be released from the first engaging hole 31 when the slide member 3 is in the second position. More specifically, since the folding direction surface 17a of the first engaging projection 17 and the locking wall W31 do not face each other in the rotation direction of the first plate portion 11, the first plate portion 11 can rotate in the folding direction so that the first engaging projection 17 can be released from the first engaging hole 31. In other words, when the slide member 3 moves relative to the first position from the first position to the second position, the engagement between the slide member 3 and the first engaging projection 17 is released, and the first plate portion 11 is allowed to rotate in the folding direction. Note that the restricting surface 342 of the first contact projection 34U and the restricting surface 182 of the first locking projection 18 are formed to be perpendicular to the first direction (left-right direction), which is the direction in which the pivot axis extends, so that the rotation of the first plate portion 11 is not hindered by the engagement between the first contact projection 34U and the first locking projection 18. Furthermore, even when the board body 1 is in the base plate state and the slide member 3 is in the second position, the locking wall W31 contacts the unfolding direction surface 17b of the first engaging projection 17 from the unfolding direction, thereby restricting the rotation of the first plate portion 11 in the unfolding direction. 【0114】 Similarly, as shown in Figure 27, when the board body 1 is in the base plate state and the slide member 3 is in the second position, the second engaging projection 57 of the second plate portion 12 is located within the release portion 321 of the second engagement hole 32. The opening width of the release portion 321 is set such that the second engaging projection 57 is allowed to disengage from the second engagement hole 32 when the slide member 3 is in the second position. More specifically, since the folding direction surface 57a of the second engaging projection 57 and the locking wall W32 do not face each other in the rotational direction of the second plate portion 12, the second plate portion 12 can rotate in the folding direction so that the second engaging projection 57 disengages from the second engagement hole 32. In other words, when the slide member 3 moves relative to the slide member 3 from the first position to the second position, the engagement between the slide member 3 and the second engaging projection 57 is released, and the second plate portion 12 is allowed to rotate in the folding direction. Furthermore, since the restricting surface 342 of the second contact projection 34L and the restricting surface 592 of the second locking projection 59 are formed to be perpendicular to the first direction (left-right direction), which is the direction in which the pivot axis extends, the rotation of the second plate portion 12 is not hindered by the engagement of the second contact projection 34L and the second locking projection 59. Also, even when the board body 1 is in the base plate state and the slide member 3 is in the second position, the locking wall W32 contacts the unfolding direction surface 57b of the second engagement projection 57 from the unfolding direction. This restricts the rotation of the second plate portion 12 in the unfolding direction. 【0115】 As described above, when the board body 1 is in the base plate state and the slide member 3 is in the second position, the engagement between the first engagement hole 31 of the slide member 3 and the first engagement projection 17 of the first plate portion 11 is released, and the engagement between the second engagement hole 32 of the slide member 3 and the second engagement projection 57 of the second plate portion 12 is released, thereby allowing the first plate portion 11 and the second plate portion 12 to rotate in the folding direction. This makes it possible to switch the board body 1 to the folded state. 【0116】 As described above, when the board body 1 is in the base plate state and the slide member 3 is in the second position, the first locking projection 18 and the second locking projection 59 engage with the slide member 3, restricting the relative movement of the slide member 3 to the first position. In other words, the engagement between the first locking projection 18 and the second locking projection 59 and the slide member 3 maintains the state in which the board body 1 is released from being fixed. Therefore, when the user rotates the first plate portion 11 and the second plate portion 12 to switch the board body 1 from the base plate state to the folded state, the user does not need to use their hands to maintain the slide member 3 in the second position. The user can switch the board body 1 from the base plate state to the folded state by gripping the first plate portion 11 and the second plate portion 12 and rotating them around the hinge portion 13. As a result, the board body 1 can be easily switched from the base plate state to the folded state. 【0117】 Figure 28 is a schematic cross-sectional view showing a cross-section of the clipboard 100 in its folded state. In Figure 28, a cross-section perpendicular to the first direction (left-right direction) is shown, corresponding to the cross-section in Figure 24. As the first plate portion 11 and the second plate portion 12 rotate in the folding direction so that the board body 1 moves from the base plate state to the folded state, the first locking projection 18 provided on the first plate portion 11 separates from the first contact projection 34U of the slide member 3, and the engagement between the first contact projection 34U and the first locking projection 18 is released. Similarly, the second locking projection 59 provided on the second plate portion 12 separates from the second contact projection 34L of the slide member 3, and the engagement between the second contact projection 34L and the second locking projection 59 is released. As a result, the slide member 3 slides in the locking direction due to the biasing force of the compression spring SP2 and reaches the first position. Because the biasing force of the compression spring SP2 causes the slide member 3 to move relative to the locking direction, the user does not need to move the slide member 3 to the first position by their own operation. As the first plate portion 11 and the second plate portion 12 rotate in the folding direction, the slide member 3 moves to the first position. In the folded state, as shown in Figure 28, the fixing portion 312 of the first engagement hole 31 corresponds to the first engagement projection 17 of the first plate portion 11, and the fixing portion 322 of the second engagement hole 32 corresponds to the second engagement projection 57 of the second plate portion 12. In the folded state, the biasing force of the compression spring SP2 maintains the slide member 3 in the first position. 【0118】 Figure 29 is a schematic cross-sectional view of the clipboard 100 during the process of switching the board body 1 from a folded state to a base plate state. In Figure 29, a cross-section perpendicular to the first direction (left-right direction) is shown, corresponding to the cross-section in Figure 24. To switch from the folded state shown in Figure 28 to the base plate state shown in Figure 24, the first plate portion 11 and the second plate portion 12 are rotated in the unfolding direction around the hinge portion 13, and the slide member 3 is engaged with the first engaging projection 17 and the second engaging projection 57. At this time, as shown in Figure 29, in the process of the first engaging projection 17 being accommodated in the first engaging hole 31 of the slide member 3, the first engaging projection 17 comes into contact with the outer surface (the surface excluding the wall surface of the hole) of the slide member 3 in the first position from the folding direction. Similarly, in the process of the second engaging projection 57 being accommodated in the second engaging hole 32 of the slide member 3, the second engaging projection 57 comes into contact with the outer surface of the slide member 3 in the first position from the folding direction. Here, the surface of the first engaging projection 17 that contacts the outer surface of the slide member 3 from the folding direction is defined as the contact projection surface 17c, and the surface of the second engaging projection 57 that contacts the outer surface of the slide member 3 from the folding direction is defined as the contact projection surface 57c. As shown in Figure 29, the contact projection surfaces 17c and 57c are curved so as to be convex in the unfolding direction. Therefore, the first engaging projection The first engagement projection 17 slides along the outer surface of the slide member 3, overcoming the outer surface and engaging with the fixing portion 312 of the first engagement hole 31, while the second engagement projection 57 slides along the outer surface of the slide member 3, overcoming the outer surface and engaging with the fixing portion 322 of the second engagement hole 32. As a result, as shown in Figure 24, the slide member 3 and the first engagement projection 17 and the second engagement projection 57 are engaged, and the base plate state of the board body 1 is maintained. 【0119】 [Cover sheet] As shown in Figure 2, the cover sheet 6 is a sheet-like member extending in the left-right direction and is attached to the back surface S2 of the board body 1 so as to cover the fixing means 20. Figure 30 is a plan view of the cover sheet 6 as seen from the front. Since the cover sheet 6 has a symmetrical shape on both sides, a plan view of the cover sheet 6 as seen from the back is omitted. Figure 31 is a plan view of the area around the cover sheet 6 of the flat clipboard 100 as seen from the back. For convenience, the fixing plate 7 is not shown in Figure 31. Also, in Figure 31, a dot pattern is applied to the portion of the cover sheet 6 that is exposed on the back side of the clipboard 100. 【0120】 The cover sheet 6 is attached to the board body 1 such that the surface visible in Figure 30 faces the back surface S2 of the board body 1. As shown in Figure 30, the cover sheet 6 is formed in a plate shape that is rectangular in plan view (more specifically, a rectangle with the longer side in the left-right direction). The cover sheet 6 is made of a flexible resin material such as polypropylene resin. However, the material of the cover sheet 6 is not limited to this. The left-right width of the cover sheet 6 is smaller than the left-right width of the hinge portion 13, and the up-down width of the cover sheet 6 is larger than the up-down width of the hinge portion 13 and smaller than the up-down width of the board body 1. 【0121】 As shown in Figure 30, the cover sheet 6 includes a sheet-like first sheet portion 61 and a sheet-like second sheet portion 62, and a hinge cover portion 63 that extends in the left-right direction (a predetermined first direction) and rotatably connects the first sheet portion 61 and the second sheet portion 62. The hinge cover portion 63 is formed in the shape of a sheet that is a rectangular shape with the left-right direction elongated in a plan view, and is formed at the center of the cover sheet 6 in the vertical direction, extending over the entire area of ​​the cover sheet 6 in the left-right direction. In the cover sheet 6, the first sheet portion 61 is positioned on the upper side, and the second sheet portion 62 is positioned on the lower side. The lower edge of the first sheet portion 61 is connected to the upper edge of the hinge cover portion 63, and the upper edge of the second sheet portion 62 is connected to the lower edge of the hinge cover portion 63. In this way, the first sheet portion 61 and the second sheet portion 62 are connected via the hinge cover portion 63. As shown in Figure 31, in the clipboard 100, the first sheet portion 61 is provided so as to overlap the first board portion 11, the second sheet portion 62 is provided so as to overlap the second board portion 12, and the hinge cover portion 63 is provided so as to overlap the hinge portion 13. In other words, the cover sheet 6 is attached to the back surface S2 of the board body 1 so as to straddle the hinge portion 13. 【0122】 Here, as shown in Figure 30, the lower edge of the first sheet portion 61 and the upper edge of the hinge cover portion 63 are connected via a hinge wire L61 extending in the left-right direction (first direction). The first sheet portion 61 is rotatable relative to the hinge cover portion 63 with the hinge wire L61 as its pivot axis. Also, the upper edge of the second sheet portion 62 and the lower edge of the hinge cover portion 63 are connected via a hinge wire L62 extending in the left-right direction (first direction). The second sheet portion 62 is rotatable relative to the hinge cover portion 63 with the hinge wire L62 as its pivot axis. In other words, the first sheet portion 61 and the hinge cover portion 63 are rotatable around the hinge cover portion 63. The cover sheet 6 is divided into the first sheet portion 61, the second sheet portion 62, and the hinge cover portion 63 by hinge wires L61 and L62 extending in the left-right direction. 【0123】 As shown in Figure 30, the first sheet portion 61 has guide holes 64 and 65 that penetrate the cover sheet 6 in the thickness direction. Guide hole 65 extends in the vertical direction and is formed so that its width increases from left to right towards the front end (upper side) of the first sheet portion 61. Guide hole 65 is provided at a position corresponding to the projection P4b of the first plate portion 11 that is fitted with the hole 41 of the second cover plate 5 in the clipboard 100, and is configured to receive the projection P4b. In this example, guide hole 65 is provided at the central position of the first sheet portion 61 in the left to right direction. Guide hole 64, similar to guide hole 65, extends in the vertical direction and is formed so that its width increases from left to right towards the front end (upper side) of the first sheet portion 61. Guide hole 64 is provided at a position corresponding to the projection P5 of the first plate portion 11 that is fitted with the projection 42 of the first cover plate 4 in the clipboard 100, and is configured to receive the projection P5. In this example, multiple guide holes 64 (four in this example) are arranged side by side with spacing between them in the left-right direction. In this example, two guide holes 64 are provided on each side of the guide hole 65. 【0124】 Furthermore, as shown in Figure 30, the second sheet portion 62 has guide holes 66 and 67 that penetrate the cover sheet 6 in the thickness direction. Guide hole 67 extends in the vertical direction and is formed so that its width increases from left to right towards the front end (bottom) of the second sheet portion 62. Guide hole 67 is provided at a position corresponding to the projection P6b of the second plate portion 12 that is fitted with the hole 51 of the second cover plate 5 in the clipboard 100, and is configured to receive the projection P6b. In this example, guide hole 67 is provided at the center position of the second sheet portion 62 in the left to right direction. Guide hole 66, similar to guide hole 67, extends in the vertical direction and is formed so that its width increases from left to right towards the front end (bottom) of the second sheet portion 62. Guide hole 66 is provided at a position corresponding to the projection P7 of the second plate portion 12 that is fitted with the projection 52 of the second cover plate 5 in the clipboard 100, and is configured to receive the projection P7. In this example, multiple guide holes 66 (four in this example) are arranged side by side with spacing between them in the left-right direction. In this example, two guide holes 66 are provided on each side of the guide hole 67. 【0125】 Furthermore, as shown in Figure 30, the hinge cover portion 63 has holes 68 and 69 that penetrate the cover sheet 6 in the thickness direction. Hole 68 is a through hole with a circular cross-section. Hole 68 is provided at a position corresponding to the projection 131 of the hinge portion 13 that is inserted through the projection guide hole 38 of the slide member 3 in the clipboard 100, and is configured to receive the projection 131. In this example, hole 68 is provided at the center of the hinge cover portion 63 in the left-right direction. Hole 69 is a through hole with a rectangular cross-section. Hole 69 is provided at a position corresponding to the pair of projections 132 of the hinge portion 13 that is inserted through the slide restricting hole 37 of the slide member 3 in the clipboard 100, and is configured to receive the pair of projections 132. In this example, multiple (four in this example) holes 69 are provided side by side with spacing in the left-right direction. In this example, two holes 69 are provided on both the left and right sides of hole 68. 【0126】 As shown in Figure 31, the cover sheet 6 is positioned on the back surface S2 of the board body 1, with the first sheet portion 61 inserted between the first plate portion 11 and the first cover plate 4 via the corrugated holes 44 of the first cover plate 4, and the second sheet portion 62 inserted between the second plate portion 12 and the second cover plate 5 via the corrugated holes 54 of the second cover plate 5, and the hinge cover portion 63 covering the fixing means 20. In this state, as will be described later, the fixing plate 7 is attached to the hinge portion 13 so that the cover sheet 6 is attached to the hinge portion 13 in a state that allows it to slide along the vertical direction. Because the fixing means 20 is covered by the cover sheet 6, situations such as the user's fingers getting caught between the first engaging projection 17 of the first plate portion 11 and the sliding member 3, or between the second engaging projection 57 of the second plate portion 12 and the sliding member 3, are suppressed when switching the board body 1 from the folded state to the base plate state. 【0127】 As shown in Figure 31, the projection P5 of the first plate portion 11, which is fitted with the projection 42 of the first cover plate 4, is inserted through the guide hole 64 of the first sheet portion 61, and the projection P4b of the first plate portion 11, which is fitted with the hole 41 of the first cover plate 4, is inserted through the guide hole 65. In addition, the projection P7 of the second plate portion 12, which is fitted with the projection 52 of the second cover plate 5, is inserted through the guide hole 66 of the second sheet portion 62, and the projection P6b of the second plate portion 12, which is fitted with the hole 51 of the second cover plate 5, is inserted through the guide hole 67. 【0128】 As shown in Figure 31, when the board body 1 is in a flat state, projection P5 (projection 42) is located at the base end (lower end) of the guide hole 64, and projection P4b (hole 41) is located at the base end (lower end) of the guide hole 65. Therefore, when the board body 1 is in a flat state, the guide hole 64 extends further forward (upward) than projection P5 (projection 42), and the guide hole 65 extends further forward (upward) than projection P4b. As a result, when the first plate portion 11 rotates in the folding direction due to the operation to switch to the folded state, projection P5 (projection 42) moves relative to the tip side (upward) within the guide hole 64, and projection P4b moves relative to the tip side (upward) within the guide hole 65, causing the first sheet portion 61 to slide along the board body 1 in a second direction. 【0129】 The vertical width of the guide hole 64 is set so that relative movement of the projection P5 (projection 52) in the second direction is permitted during the switching operation between the base plate state and the folded state. Similarly, the vertical width of the guide hole 65 is set so that relative movement of the projection P4b in the second direction is permitted during the switching operation between the base plate state and the folded state. Therefore, during the switching operation between the base plate state and the folded state, the first sheet portion 61 can maintain a state aligned with the board body 1. 【0130】 Furthermore, as shown in Figure 31, when the board body 1 is in a flat state, projection P7 (projection 52) is located at the base end (upper end) of the guide hole 66, and projection P6b is located at the base end (upper end) of the guide hole 67. Therefore, the guide hole 66 extends further forward (downward) than projection P7 (projection 52), and the guide hole 67 extends further forward (downward) than projection P6b. As a result, when the second plate portion 12 rotates in the folding direction due to the operation to switch to the folded state, projection P7 (projection 52) moves relative to the front end (downward) within the guide hole 66, and projection P6b moves relative to the front end (downward) within the guide hole 67, causing the second sheet portion 62 to slide along the board body 1 in the second direction. 【0131】 The vertical width of the guide hole 66 is set so that relative movement of the projection P7 (projection 52) in the second direction is permitted during the switching operation between the base plate state and the folded state. Similarly, the vertical width of the guide hole 67 is set so that relative movement of the projection P6b in the second direction is permitted during the switching operation between the base plate state and the folded state. Therefore, during the switching operation between the base plate state and the folded state, the second sheet portion 62 can maintain a state aligned with the board body 1. 【0132】 As described above, the cover sheet 6 is held by the first cover plate 4 and the second cover plate 5 so that it can slide along the board body 1 in a second direction (up and down direction) in accordance with the rotation of the first plate portion 11 and the second plate portion 12. Maintaining the cover sheet 6 in a state along the board body 1 prevents the cover sheet 6 from becoming bulky during the switching operation between the base plate state and the folded state. Furthermore, the first sheet portion 61 is held down from the back side in the thickness direction to the front side (first plate portion 11 side) by a retaining piece 47 provided on the first cover plate 4 that protrudes toward the base end, and the second sheet portion 62 is held down from the back side in the thickness direction to the front side (second plate portion 12 side) by a retaining piece 58 provided on the second cover plate 5 that protrudes toward the base end, thereby more effectively preventing the cover sheet 6 from becoming bulky. 【0133】 [Fixing plate] As shown in Figure 2, the fixing plate 7 is a plate member extending in the left-right direction, and is attached to the back surface S2 of the hinge portion 13 by sandwiching the slide member 3 and cover sheet 6 between it and the hinge portion 13, thereby fixing the slide member 3 and cover sheet 6 to the board body 1. Figure 32 is a plan view of the fixing plate 7 as seen from the front. Figure 33 is a plan view of the fixing plate 7 as seen from the back. The fixing plate 7 is attached to the hinge portion 13 such that the surface visible in Figure 32 faces the back surface S2 of the board body 1. As shown in Figures 32 and 33, the fixing plate 7 is formed in a plate shape that is rectangular in plan view (more specifically, a rectangle with the longer side in the left-right direction). The fixing plate 7 is made of a resin material such as polycarbonate, for example. However, the material of the fixing plate 7 is not limited to this. The width of the fixing plate 7 is about the same as the width of the cover sheet 6 and is smaller than the width of the hinge portion 13, and the height of the fixing plate 7 is smaller than the height of the hinge portion 13. 【0134】 As shown in Figure 32, on the clipboard 100, a cylindrical projection 71 protruding in the thickness direction is formed on the surface of the fixing plate 7 facing the back surface S2 of the hinge portion 13. The projection 71 is provided in the clipboard 100 at a position corresponding to the projection 131 of the hinge portion 13 that is inserted through the projection guide hole 38 of the slide member 3 and the hole 68 of the cover sheet 6, and is configured to engage with the projection 131. In this example, the projection 71 is provided at the center of the fixing plate 7 in the left-right direction. In addition, a T-shaped projection 72 protruding in the thickness direction is formed on the surface of the fixing plate 7. The projection 72 is provided in the clipboard 100 at a position corresponding to the pair of projections 132 of the hinge portion 13 that is inserted through the slide restricting hole 37 of the slide member 3 and the hole 69 of the cover sheet 6, and is configured to be clamped by a pair of projections 132a, 132a of the pair of projections 132. In this example, multiple (four in this example) projections 72 are provided side by side with spacing in the left-right direction. In this example, two protrusions 72 are provided on each of the left and right sides of the protrusion 71. 【0135】 Figure 34 is a plan view of the area around the fixing plate 7 of the flat clipboard 100 as seen from the back. In Figure 34, the fixing plate 7 has a dot pattern. As shown in Figure 34, the fixing plate 7 is attached to the back surface S2 of the hinge portion 13 by the fact that projection 71 fits with projection 131 of the hinge portion 13 and projection 72 is sandwiched between a pair of projections 132a, 132a of projection pair 132. In this way, the slide member 3 and the cover sheet 6 are fixed to the board body 1. 【0136】 [Restraining sheet] As shown in Figures 1 and 5, the retaining sheet 8 is a sheet-like member extending in the left-right direction, and is attached to the surface S1 near the lower end of the second plate portion 12, thereby forming an insertion portion 8a between it and the second plate portion 12, which is a gap into which a piece of paper can be inserted. Figure 35 is a plan view of the retaining sheet 8 as seen from the front. Note that since the retaining sheet 8 has a symmetrical shape on both sides, a plan view of the retaining sheet 8 as seen from the back is omitted. Figure 36 is a plan view of the clipboard 100 in a flat state holding a piece of paper as seen from the front. 【0137】 The cover sheet 6 is attached to the board body 1 such that the surface visible in Figure 35 faces the surface S1 of the board body 1. As shown in Figure 35, the retaining sheet 8 is formed in the form of a sheet that is substantially rectangular in shape (more specifically, substantially rectangular in length in the left-right direction) when viewed from above. The retaining sheet 8 is formed to be flexible using a resin material such as polypropylene resin. However, the material of the retaining sheet 8 is not limited to this. The left-right width of the retaining sheet 8 is smaller than the left-right width of the second plate portion 12, and the up-down width of the retaining sheet 8 is smaller than the up-down width of the second plate portion 12. 【0138】 As shown in Figure 35, the clamping sheet 8 has a rectangular shape that is elongated in the left-right direction. It includes 1, a protruding portion 82 that is connected to the upper edge of the clamped portion 81 and has a rectangular shape that is elongated in the left-right direction, and a folded portion 83 that is connected to the upper edge of the protruding portion 82 and has a rectangular shape that is elongated in the left-right direction. 【0139】 The clamped portion 81 is the part of the clipboard 100 that is clamped between the retaining sheet fixing panel 14, which is folded to the front side, and the second plate portion 12. The clamped portion 81 has a rectangular cross-section hole 84 that penetrates the retaining sheet 8 in the thickness direction. The hole 84 is provided at a position corresponding to the projection P1 of the retaining sheet fixing panel 14 that fits into the hole H5 of the second plate portion 12 in the clipboard 100, and is configured to receive the projection P1. In this example, multiple (three in this example) holes 84 are provided side by side in the left-right direction near the lower end of the clamped portion 81. The clamped portion 81 protrudes from between the retaining sheet fixing panel 14 and the second plate portion 12 to the base end side (upper side) of the second plate portion 12 in the clipboard 100, thereby forming an insertion portion 8a between it and the second plate portion 12. The folded portion 83 is connected to the upper edge of the protruding portion 82 via a fold line L81 that extends in the first direction (left-right direction). The folded portion 83 is folded back to the back side along the fold line L81, and together with the clamped portion 81, is clamped between the retaining sheet fixing panel 14 and the second plate portion 12. The vertical width of the folded portion 83 is greater than the vertical width of the protruding portion 82. 【0140】 With the folded portion 83 folded to the back, the projection P1 of the retaining sheet fixing panel 14 is inserted through the hole 84 of the clamped portion 81, the projection P1 is fitted into the hole H5 of the second plate portion 12, and the projection P2 of the retaining sheet fixing panel 14 is fitted into the recess D3 of the second plate portion 12. As a result, the clamped portion 81 and the folded portion 83 are clamped between the retaining sheet fixing panel 14, which is folded to the front side of the second plate portion 12, and the second plate portion 12. This allows the retaining sheet 8 to be attached to the lower end of the second plate portion 12. 【0141】 As shown in Figure 36, when a long piece of paper 200 is held on the clipboard 100 in its base plate state, for example, in the second direction (up and down direction), the upper end of the paper piece 200 is held between the flap plate 2 and the first plate portion 11 by a clamping device 10 provided at the upper end of the board body 1 (upper end of the first plate portion 11), and the lower end of the paper piece 200 can be inserted into an insertion portion 8a formed at the lower end of the board body 1 (lower end of the second plate portion 12). The lower end of the paper piece 200 inserted between the retaining sheet 8 and the second plate portion 12 is held down by the retaining sheet 8 from the front side in the thickness direction to the back side (second plate portion 12 side). As a result, the paper piece 200 is less likely to fall off the clipboard 100, and the paper piece 200 is prevented from curling up from the lower end that is not held by the clamping device 10, thereby improving the convenience of the clipboard 100 in its base plate state. 【0142】 [Securing band] As shown in Figures 2 and 6, the fixing band B1 is an elastic member formed in the shape of a long strip in the left-right direction. The fixing band B1 is, for example, a rubber band. However, the material of the fixing band B1 is not limited to this. The fixing band B1 is attached to the back surface S2 of the first plate portion 11 and fastens the first plate portion 11 and the second plate portion 12 together when the board body 1 is folded, thereby fixing the board body 1 in the folded state. 【0143】 As shown in Figure 2, the end of the fixing band B1 is passed through the hole H3 of the first plate portion 11 from the back side, then through the hole H2 from the front side, and the projection P3 of the band fixing panel 15, which is folded toward the surface S1 side of the first plate portion 11, is fitted into the hole H2, thereby sandwiching the end of the fixing band B1 between the band fixing panel 15 and the first plate portion 11. By fixing both ends of the fixing band B1 to the board body 1 in this way, the fixing band B1 is attached to the board body 1. 【0144】 As shown in Figure 4, in the folded state of the board body 1, the fixing band B1 is attached to the first board portion By flipping the first plate portion 11 from the back surface S2 side to the back surface S2 side of the second plate portion 12, the first plate portion 11 and the second plate portion 12 are fastened together. This prevents the first plate portion 11 and the second plate portion 12 from unintentionally rotating in the unfolding direction. In other words, the board body 1 is fixed in the folded state. At this time, a retaining groove G1 capable of holding the fixing band B1 is formed between the rib 121 and the projection P8 formed on the back surface S2 of the second plate portion 12. In the folded state, the retaining groove G1 is located on the opposite side of the fixing end of the fixing band B1. By placing the fixing band B1, which has been flipped to the back surface S2 side of the second plate portion 12 in the folded state of the board body 1, in the retaining groove G1, displacement of the fixing band B1 is suppressed. As a result, the board body 1 can be fixed in the folded state more securely. 【0145】 [Pen holder plate] Figure 37 is a plan view of the pen holder plate 9 as seen from the front. Figure 38 is a plan view of the pen holder plate 9 as seen from the back. Figure 39 is a plan view of the area around the pen holder plate 9 of the flat clipboard 100 as seen from the back, showing the pen holder plate 9 in its stored state. Figure 40 is a plan view of the area around the pen holder plate 9 of the flat clipboard 100 as seen from the back, showing the pen holder plate 9 in use. The pen holder plate 9 is attached to the upper end of the first plate portion 11 such that the surface visible in Figure 37 faces the back surface S2 of the board body 1. The pen holder plate 9 is attached to the first plate portion 11 so that it can slide in a second direction, allowing it to switch between a stored state where it is stored in the board body 1 as shown in Figure 39 and a use state where it protrudes upward from the first plate portion 11 as shown in Figure 40. By using the pen holder plate 9 in its use state, a writing instrument with a clip (e.g., a ballpoint pen) can be held. 【0146】 As shown in Figures 37 and 38, the pen holder plate 9 is formed in a plate shape that is approximately rectangular in shape (more specifically, a rectangle with the longer side in the left-right direction) when viewed from above. The pen holder plate 9 is made of a resin material such as polycarbonate, for example. However, the material of the pen holder plate 9 is not limited to this. The left-right width of the pen holder plate 9 is smaller than the left-right width of the first plate portion 11, and the up-down width of the pen holder plate 9 is smaller than the up-down width of the first plate portion 11. Also, the thickness of the pen holder plate 9, excluding the protrusion indicated by reference numeral 94, is smaller than the width of the outlet H61 in the thickness direction. 【0147】 As shown in Figures 37 and 38, the pen holder plate 9 has a slide hole 91 formed in the thickness direction, which is a through hole with a rectangular cross-section that is elongated in the vertical direction. It is located at a position corresponding to the projection 165 of the holder storage panel 16 that is folded to the back side of the clipboard 100, and is configured to receive the projection 165. In this example, the slide hole 91 is located at the center of the pen holder plate 9 in the left-right direction. The slide hole 91 extends in the vertical direction so that the pen holder plate 9 can move vertically when the projection 165 is received in the slide hole 91. 【0148】 Furthermore, a rectangular slit 93 is formed along the left and right side edges of the lower edge of the pen holder plate 9. The slit 93 extends in the vertical direction. In this example, one slit 93 is formed near the left edge and one near the right edge of the pen holder plate 9. The formation of the slit 93 creates a flexible elastic locking piece 92 in the portion of the pen holder plate 9 that is outside the slit 93 in the left-right direction. One elastic locking piece 92 is formed on each of the left and right side edges. In addition, a projection 92a is formed at the lower end of the elastic locking piece 92, which protrudes outward from the pen holder plate 9 in the left-right direction. The outer surface of the projection 92a is formed in an arc shape that is convex outward from the pen holder plate 9 in the left-right direction, so that it can engage with the recesses 162 and 163 of the holder storage panel 16. 【0149】 Furthermore, semicircular recesses 95 are formed on the left and right side edges of the pen holder plate 9. The recesses 95 are formed on the part of the pen holder plate 9 that protrudes from the board body 1 when in use, and are located above the slide holes 91. 【0150】 Furthermore, as shown in Figure 38, a projection 94 is formed on the back surface of the pen holder plate 9, protruding in the thickness direction. The projection 94 is located at a position corresponding to the window portion H62 of the holder storage panel 16 that is folded to the back side of the clipboard 100, and is configured to be able to be received by the window portion H62. 【0151】 Furthermore, as shown in Figures 37 and 38, the pen holder plate 9 has a suspension hole 96 formed therein, which is a through hole drilled in the thickness direction and has a rectangular cross-section that is elongated in the vertical direction. The suspension hole 96 is formed in the part of the pen holder plate 9 that protrudes from the board body 1 when in use, and is located above the elastic locking piece 92. 【0152】 As shown in Figure 39, the pen holder plate 9 is placed in the recess 113 of the first plate portion 11, the holder storage panel 16 is folded to the back so that the pen holder plate 9 is received between the pair of guide wall portions 161, 161 and the projection 165 is received in the slide hole 91, and the projection 164 of the holder storage panel 16 is fitted into the hole H4 of the first plate portion 11, thereby storing the pen holder plate 9 between the holder storage panel 16 and the first plate portion 11. 【0153】 As shown in Figures 39 and 40, in the clipboard 100 (i.e., in the assembled state of the board body 1), the exit H61 of hole H6 opens upward, and the pen holder plate 9 can be inserted into and removed from the board body 1 via the exit H61. In addition, in the clipboard 100, the window H62 of hole H6 opens on the back side, and the user can contact the stored pen holder plate 9 via the window H62. The pen holder plate 9 can slide vertically because the sliding hole 91 of the pen holder plate 9 is guided by the projection 165 of the holder storage panel 16. The vertical width of the sliding hole 91 is set so that the pen holder plate 9 can slide the distance necessary to switch between the stored state and the usage state. 【0154】 As shown in Figure 39, the pen holder plate 9 in its stored state is housed inside the board body 1 (more specifically, between the holder storage panel 16 and the first board portion 11). In the stored state, the lower edge of the pen holder plate 9 abuts against the lower edge wall surface of the recess 113, and the projection 165 of the holder storage panel 16 abuts against the upper edge wall surface of the slide hole 91. This restricts the pen holder plate 9 from moving downward relative to the board body 1. Also in the stored state, the protruding portion 92a of the pen holder plate 9 engages with the recess 162 of the guide wall portion 161. This prevents the pen holder plate 9 from unintentionally sliding upward and protruding from the board body 1. Furthermore, in the stored state, the slide hole 91 of the pen holder plate 9 extends downward below the projection 165. This allows the pen holder plate 9 to move upward relative to the board body 1. In addition, in the stored state, the projection 94 is located within the window portion H62. This allows the user to move the pen holder plate 9 upwards, for example, by hooking their finger onto the projection 94 through the window portion H62. 【0155】 To switch the pen holder plate 9 from the stored state to the usable state, simply slide the pen holder plate 9 upward. When attempting to move the pen holder plate 9 upward while it is in the stored state, the elastic locking piece 92 bends inward in the left-right direction of the pen holder plate 9, releasing the engagement between the protrusion 92a and the recess 162. This releases the projection 16 Guided by 5, the pen holder plate 9 slides upward, resulting in the usage state shown in Figure 40. 【0156】 As shown in Figure 40, in the state of use, the pen holder plate 9 protrudes upward from the drawer H61 to the outside of the board body 1. This allows the user to hold a writing instrument, for example, by attaching a writing instrument with a clip to the pen holder plate 9. Also, in the state of use, the projection 165 of the holder storage panel 16 abuts against the wall surface of the lower edge of the slide hole 91. This restricts the relative upward movement of the pen holder plate 9 relative to the board body 1, preventing the pen holder plate 9 from falling out of the board body 1. In addition, in the state of use, the projection 92a of the pen holder plate 9 engages with the recess 163 of the guide wall 161. This prevents the pen holder plate 9 from unintentionally sliding downward and being stored in the board body 1. Furthermore, in the state of use, the slide hole 91 of the pen holder plate 9 extends upward above the projection 165. This allows the pen holder plate 9 to be moved downward relative to the board body 1 to the stored position. Moreover, in the state of use, the recess 95 is located outside the board body 1. This allows the user to secure a writing instrument with a clip, for example, by inserting it into the recess 95 and then attaching it to the pen holder plate 9, thus providing a more stable hold for the writing instrument. In addition, when in use, the hanging hole 96 is located on the outside of the board body 1. This allows the user to hang the clipboard on a wall or the like by, for example, hooking a hook into the hanging hole 96. 【0157】 To switch the pen holder plate 9 from the usage state to the stored state, simply slide the pen holder plate 9 downwards. When attempting to move the pen holder plate 9 downwards from the usage state, the elastic locking piece 92 bends inward in the left-right direction of the pen holder plate 9, releasing the engagement between the protrusion 92a and the recess 163. As a result, guided by the projection 165, the pen holder plate 9 slides downwards, resulting in the stored state shown in Figure 39. 【0158】 As described above, the pen holder plate 9 is retractable, so the user can pull it out from the board body 1 as needed. When not in use, the pen holder plate 9 can be stored away so that it does not interfere with the use of the clipboard 100. 【0159】 [Effects / Effects] As described above, the clipboard 100 according to this embodiment comprises a plate-shaped board body 1 having a surface S1 and a back surface S2, and a clipping tool 10 capable of holding a piece of paper between itself and the board body 1. The board body 1 also includes a plate-shaped first plate portion 11 and a plate-shaped second plate portion 12, and a hinge portion 13 that extends in a predetermined first direction (left-right direction in this example) and rotatably connects the first plate portion 11 and the second plate portion 12. The board body 1 can be switched between a base plate state in which the board body 1 forms a flat plate shape by rotating the first plate portion 11 and the second plate portion 12 around the hinge portion 13, and a folded state in which the board body 1 is folded at the hinge portion 13 so that the surfaces S1 of the first plate portion 11 and the second plate portion 12 face each other. Furthermore, the clipboard 100 according to this embodiment further comprises a fixing means 20 provided on the back surface of the board body 1 that can fix the board body 1 in the base plate state. The fixing means 20 includes a slide member 3 attached to the hinge portion 13 so as to be displaceable along the first direction within a range including a first position and a second position that are separated from each other in the first direction, a first engaging projection 17 provided on the first plate portion 11, and a second engaging projection 57 provided on the second plate portion 12. When the board body 1 is in the base plate state and the slide member 3 is in the first position, the slide member 3 engages with the first engaging projection 17 and the second engaging projection 57, thereby restricting the rotation of the first plate portion 11 and the second plate portion 12. When the board body 1 is in the base plate state and the slide member 3 moves from the first position to the second position, the engagement between the slide member 3 and the first engaging projection 17 and the second engaging projection 57 is released. This allows the first plate portion 11 and the second plate portion 12 to rotate. 【0160】 As described above, the clipboard 100 according to this embodiment is highly portable because the board body 1 can be switched from a base plate state to a folded state. Furthermore, with the clipboard 100 according to this embodiment, the board body 1 can be fixed in the base plate state by the fixing means 20, so that the first plate portion 11 and the second plate portion 12 do not rotate unintentionally. As a result, the clipboard 100 does not close unintentionally while using the clipboard 100 in the base plate state, and the clipboard 100 can be used stably as a base plate for reading and writing on paper. This improves the convenience of the clipboard 100. Furthermore, with the clipboard 100 according to this embodiment, the fixing of the board body 1 to the base plate state can be released simply by moving (displacing) the slide member 3 along the first direction from the first position to the second position. This makes it easy to switch the board body 1 from the base plate state to the folded state. As a result, the portability of the clipboard 100 is further improved. 【0161】 Furthermore, the slide member 3 of the clipboard 100 according to this embodiment has a first engagement hole 31 that engages with a first engagement projection 17 and a second engagement hole 32 that engages with a second engagement projection 57. In this embodiment, the first engagement projection 17 is formed as a projection, and the first engagement hole 31 is formed as a hole into which the first engagement projection 17 fits when the board body 1 is in a base plate state and the slide member 3 is in a first position. Also, in this embodiment, the second engagement projection 57 is formed as a projection, and the second engagement hole 32 is formed as a hole into which the second engagement projection 57 fits when the board body 1 is in a base plate state and the slide member 3 is in a first position. 【0162】 As described above, the clipboard 100 according to this embodiment can fix the board body 1 in a base plate state by restricting the rotation of the first plate portion 11 and the second plate portion 12 by utilizing the fitting of the projection and the hole. In this embodiment, the first engaging portion is formed as a projection, the first locking portion is formed as a hole, the second engaging portion is formed as a projection, and the second locking portion is formed as a hole, but the present invention is not limited thereto. The present invention may also have a configuration in which one of the first engaging portion and the first locking portion is formed as a projection and the other as a hole, and one of the second engaging portion and the second locking portion is formed as a projection and the other as a hole. For example, the first locking portion may be formed as a projection and the first engaging portion may be formed as a hole that fits with the projection, or the second locking portion may be formed as a projection and the second engaging portion may be formed as a hole that fits with the projection. 【0163】 Furthermore, the slide member 3 of the clipboard 100 according to this embodiment is configured such that when the slide member 3 is in the first position, the board body 1 switches from a folded state to a base plate state, allowing it to engage with the first engaging projection 17 and the second engaging projection 57. The fixing means 20 further includes a compression spring SP2 that biases the slide member 3 in the locking direction (from the side of the second position toward the side of the first position). 【0164】 According to this, when the board body 1 is folded, the sliding member 3 is maintained in the first position by the biasing force of the compression spring SP2. Therefore, the user does not need to move the sliding member 3 to the first position by their own operation, and can fix the board body 1 in the base plate state simply by switching the board body 1 from the folded state to the base plate state. As a result, the operability of the clipboard 100 is further improved. Note that the biasing member is not an essential component in this invention. 【0165】 Furthermore, the fixing means 20 of the clipboard 100 according to this embodiment further includes a first locking projection 18 (first restricting part) provided on the first plate portion 11 and a second locking projection 59 (second restricting part) provided on the second plate portion 12. The first locking projection 18 and the second locking projection 59 are located on the board body 1 When the base plate is in place and the slide member 3 is in the second position, the first plate portion 11 and the second plate portion 12 engage with the hinge portion 13, restricting the movement of the slide member 3 in the locking direction (from the side of the second position to the side of the first position). Then, when the board body 1 is in place and the slide member 3 is in the second position, the first plate portion 11 and the second plate portion 12 rotate around the hinge portion 13 so that the board body 1 is folded, thereby releasing the engagement between the first locking projection 18 and the second locking projection 59 and the slide member 3. 【0166】 In other words, when the board body 1 is in the base plate state and the slide member 3 is in the second position, the first locking projection 18 and the second locking projection 59 engage with the slide member 3, restricting the relative movement of the slide member 3 to the first position, and maintaining the state in which the board body 1 is released from fixation. Therefore, when the user rotates the first plate portion 11 and the second plate portion 12 to switch the board body 1 from the base plate state to the folded state, the user does not need to use their hand to maintain the slide member 3 in the second position. This makes it easy to switch the board body 1 from the base plate state to the folded state. As a result, the operability of the clipboard 100 is further improved. In this embodiment, restricting portions (first locking projection 18 and second locking projection 59) are provided on both the first plate portion 11 and the second plate portion 12, but the present invention is not limited to this. The fixing means may be configured such that the restricting portion is provided on at least one of the first plate portion and the second plate portion. For example, the restricting portion may be provided on only one of the first plate portion and the second plate portion. 【0167】 Furthermore, the clipping device 10 of the clipboard 100 according to this embodiment is provided on the first plate portion 11 and clamps one end (upper end) of the paper piece 200 in a second direction (up and down in this example) perpendicular to the first direction between itself and the first plate portion. In the clipboard 100 according to this embodiment, the second plate portion 12 has an insertion portion 8a into which the other end (lower end) of the paper piece in the second direction can be inserted. 【0168】 According to this configuration, the clamping device 10 holds one end (upper end) of the paper piece 200, and the other end (lower end) of the paper piece 200 can be inserted into the insertion part 8a, making it difficult for the paper piece 200 to fall out. In addition, the paper piece 200 is prevented from curling up from the other end that is not held by the clamping device 10, so that reading and writing of the paper piece can be performed stably in the base plate state. As a result, the convenience of the clipboard 100 as a base plate is further improved. In this embodiment, the clamping device 10 is provided on the first plate portion 11 and the insertion part 8a is formed on the second plate portion 12, but the present invention is not limited to this. The present invention may also be configured such that the clamping device is provided on one of the first plate portion and the insertion part is formed on the other. For example, the clamping device may be provided on the second plate portion and the insertion part may be formed on the first plate portion. 【0169】 Furthermore, the clipboard 100 according to this embodiment further comprises a cover sheet 6 provided on the back surface S2 of the board body 1 so as to cover the fixing means 20, and a first cover plate 4 (first holding member) and a second cover plate 5 (second holding member) that hold the cover sheet 6 so that the cover sheet 6 can slide along the board body 1 in a second direction (up and down in this example). 【0170】 According to this, the fixing means 20 is covered by the cover sheet 6, which prevents the user's fingers from getting caught between the first engaging projection 17 of the first plate portion 11 and the sliding member 3, or between the second engaging projection 57 of the second plate portion 12 and the sliding member 3, when switching the board body 1 from the folded state to the base plate state. Furthermore, the cover sheet 6 is kept in a position along the board body 1 by the first cover plate 4 and the second cover plate 5, which prevents the cover sheet 6 from becoming bulky when switching between the base plate state and the folded state. As a result, the operability of the clipboard 100 is further improved. 【0171】 Furthermore, the clipboard 100 according to this embodiment includes a pen holder plate 9 that can switch between a stored state in which it is housed within the board body 1 and a usage state in which it protrudes from the upper edge of the board body 1 to the outside of the board body 1. 【0172】 According to this, the clipboard 100 is further improved in terms of convenience by having a retractable pen holder plate 9. In this embodiment, the pen holder plate 9 is configured to protrude from the upper edge of the board body 1, but the present invention is not limited to this. The pen holder member may be configured to protrude from any edge of the board body. 【0173】 <Other> Although embodiments of the clipboard according to the present invention have been described above, the present invention is not limited to the above embodiments and can be modified as appropriate without departing from the spirit of the invention. [Explanation of Symbols] 【0174】 1. Board body 3. Sliding member (an example of a locking member) 4. First cover plate (an example of a retaining member) 5. Second cover plate (an example of a retaining member) 6. Cover sheet (an example of a cover component) 10... Clipper 11...1st plate part 12...Second plate part 13. Hinge section 17. First engaging projection (an example of the first engaging portion) 18. First locking projection (an example of a regulating part) 20...Fixing means 31. First engagement hole (an example of the first locking part) 32.....Second engagement hole (an example of the second locking part) 57.....Second engaging projection (an example of the second engaging part) 59..Second locking projection (an example of a regulating part) 100...Foldable clipboard (an example of a clipboard)

Claims

[Claim 1] A clipboard comprising a plate-shaped board body having a front and a back surface, and a clipping device capable of holding a piece of paper between itself and the board body, The board body includes a plate-shaped first plate portion and a plate-shaped second plate portion, and a hinge portion that extends in a predetermined first direction and rotatably connects the first plate portion and the second plate portion. The board body is switchable between a base plate state in which the board body forms a flat plate shape by the rotation of the first plate portion and the second plate portion around the hinge portion, and a folded state in which the board body is folded at the hinge portion so that the surfaces of the first plate portion and the second plate portion face each other. The clipboard further comprises fixing means provided on the back surface of the board body, which can fix the board body in the base plate state, The fixing means includes a locking member attached to the hinge portion so as to be displaceable along the first direction within a range including a first position and a second position that are separated from each other in the first direction, a first engaging portion provided on the first plate portion, and a second engaging portion provided on the second plate portion. When the board body is in the base plate state and the locking member is in the first position, the locking member engages with the first engaging portion and the second engaging portion, thereby restricting the rotation of the first plate portion and the second plate portion. When the board body is in the base plate state and the locking member moves from the first position to the second position, the engagement between the locking member and the first engaging portion and the second engaging portion is released, thereby allowing the rotation of the first plate portion and the second plate portion. Clipboard. [Claim 2] The locking member has a first locking portion that engages with the first engaging portion and a second locking portion that engages with the second engaging portion. One of the first engaging portion and the first locking portion is formed as a projection, and the other is formed as a hole into which the projection fits when the board body is in the base plate state and the locking member is in the first position. One of the second engaging portion and the second locking portion is formed as a projection, and the other is formed as a hole into which the projection fits when the board body is in the base plate state and the locking member is in the first position. The clipboard according to claim 1. [Claim 3] The locking member is configured such that it can engage with the first engaging portion and the second engaging portion when the board body switches from the folded state to the base plate state while the locking member is in the first position. The fixing means further includes a biasing member that biases the locking member from the second position side to the first position side. The clipboard according to claim 1 or 2. [Claim 4] The fixing means further includes a restricting portion provided on at least one of the first plate portion and the second plate portion, which engages with the locking member when the board body is in the base plate state and the locking member is in the second position, thereby restricting the movement of the locking member from the second position side to the first position side. When the board body is in the base plate state and the locking member is in the second position, the first plate portion and the second plate portion rotate around the hinge portion so that the board body is in the folded state, thereby releasing the engagement between the restricting portion and the locking member. The clipboard according to claim 3. [Claim 5] The clamping device is provided on one of the first plate portion and the second plate portion, and in the first direction In contrast, one end of the paper piece in a second direction perpendicular to it is sandwiched between the first and second sides. The other of the first and second plate portions has an insertion portion into which the other end of the paper piece in the second direction can be inserted. The clipboard according to claim 1 or 2. [Claim 6] A cover member is provided on the back surface of the board body so as to cover the aforementioned fixing means, The system further comprises a holding member that holds the cover member so that the cover member can slide along the board body in a second direction perpendicular to the first direction, while being aligned with the board body. The clipboard according to claim 1 or 2. [Claim 7] The system further includes a pen holder member that can switch between a stored state, where the pen is housed within the board body, and a usage state, where the pen protrudes from the edge of the board body to the outside of the board body. The clipboard according to claim 1 or 2.

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