JPH0455043B2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to improvements in lecterns.

[Prior Art] A conventional lectern (an unknown device related to the application filed by the present applicant) is assembled from a molded material 1 made of a thin plate material such as plastic or cardboard, as shown in FIG. It is something. The forming material 1 has a truncated chevron-shaped portion 2 formed by two bending lines a, a from both ends of the truncated portion.
is hung down to form a central back plate 3 and side plates 4, 4 on both sides, and an edge piece 4a that can be bent outward at right angles is formed at the lower end of each side plate 4.
A vertically long rectangular portion 5 is integrally constructed or connected to the lower end of the vertically rectangular portion 5 along a bending line b, and the vertically long rectangular portion 5 is connected to an upper bottom plate 6 and a lower folded portion 7 along a bending line c.
The lower folded portion 7 is further divided by two folding lines d and e. To assemble the lectern 8 using this forming material 1, as shown in FIG. Bend the chevron part 2 (see Figure 15) along line b
The side plates 4, 4 on both sides are bent forward while the side plates 4, 4 on both sides are raised up to form a planar standing wall with sloped edges 4c, 4c with a downward slope toward the front.
The outer curved edges 4a, 4a at the lower ends of 4 are fixed to the bottom plate 6 as they are at the rear or as appropriate as necessary, and the outer curved edges 4a, the folded portion 7, and the bottom plate 6 are perforated at the front portions of both sides. Holes 4b, 7b, 6b
Complete the process by fixing it with fasteners 10, 10 made of cotter pins, hooks, etc.
(see figure), and the assembled lectern 8 is
Although not shown, the downward slope 4c of the side plates 4, 4,
The lower end of the book leaning against the 4c was supported by a non-slip member 9, so that the book stood at an angle of approximately 45 degrees, which was optimal for reading. (See Figure 3 of the device No. 99320).

[Problems to be Solved by the Invention] However, the conventional lectern 8 has the following drawbacks.

(a) Since the triangular side surface of the non-slip 9 remains raised, the non-slip 9 becomes a hindrance when carrying or storing the device, and may be crushed.

(b) Since the side plate 4 remains standing from the bottom plate 6, it is very bulky and very inconvenient to carry or store.

The present invention has been devised to eliminate the above drawbacks.

[Means for Solving the Problems] Means for solving the above problems will be explained using drawings corresponding to embodiments.

The first invention has a bottom plate 16 as shown in FIG.
In a lectern, left and right side plates 14, 14 having sloped edges 14c with a downward slope toward the front are erected, and a non-slip 19 is formed in front of the bottom plate 16. A mountain-folded piece 17a is formed that is bendably joined to the front edge and has a mountain-fold line d, which serves as a top ridgeline, extending in the left-right direction near the center of its longitudinal width, and on the rear edge of the mountain-folded piece 17a, A sliding piece 17c that can be slidably stacked on the bottom plate 16 is connected in a bendable manner, and the sliding piece 17c and the bottom plate 16 are provided with elongated holes 17b, 17b that are long in the front-rear direction and bored in one of them. It is slidably fastened with arbitrary fasteners 10, 10 through fastening holes 16b, 16b (see Fig. 2) drilled in the other side, thereby making it possible to raise and lower the mountain folded piece 17a by sliding. .

The second invention, as shown in FIG.
In a lectern, left and right side plates 34, 34 having sloped edges 34c that are downwardly sloped from the front are erected on top of the lectern, and a non-slip 39 is formed in front of the bottom plate 36. A mountain-folded piece 37a is formed, which is bendably joined to the front edge of the mountain-folded piece 37a and has a mountain-fold line d, which is a top ridge line, along the left-right direction near the front-rear width center of the mountain-folded piece 37a. , a sliding piece 37c slidably stacked on the bottom plate 36 is connected in a bendable manner, and the sliding piece 37
c and the bottom plate 36 are slidably fastened with appropriate fasteners 10, 10 through elongated holes 37b, 37b drilled in the front-rear direction and fastening holes 36b, 36b drilled in the other side. The left and right side plates 34, 34 have their lower edges bendably joined to the left and right sides of the bottom plate 36, and their vertical ridgeline portions a. , a are bentably erected from the bottom plate 36 and can be bent freely with or without the back plate 33 (not shown), and the vertical ridgeline portions a, a lower end of the slope edge 3
By forming inclined folds f and f reaching 4c and 34c, it is possible to fold it into a flat shape.

In the third invention, as shown in FIGS. 12 and 13, left and right side plates 34, 34 having sloped edges 34a with a downward slope relative to the front are erected on the bottom plate 36, and the front of the bottom plate 36 is A unit base 38' having a non-slip 39 formed thereon, and a non-slip 39 of the unit base 38'.
A unit base 38 is attached to the upper end of a standing wall part 43 that is bendably connected to the rear of a bottom plate part 42 which has a bent opening edge 41 at the front end of a cover folding plate 40 that encloses the same. In the lectern combined with a covering bending plate 40 formed by bendably connecting a sloped wall portion 44 that covers at least the upper side of the sloped edges 34a, 34a of the unit base 38', the unit base 38' The anti-slip 39 is formed into a mountain-fold piece 37a which is bendably joined to the front edge of the bottom plate 36 and has a mountain-fold line d, which is a top ridgeline, along the left-right direction near the center of the front-to-back width thereof. A sliding piece 37c, which is slidably stacked on the bottom plate 36, is connected to the rear edge of the mountain-folded piece 37a in a bendable manner, and the sliding piece 37c and the bottom plate 36 are bored in one of them. By slidingly fixing it with an appropriate fastener 10 through a longitudinally long long hole (not shown) and a stopper hole drilled in the other side (not shown), it is possible to raise and lower the mountain-folded piece 37a by sliding it. The left and right side plates 34, 34 of the unit base 38' are bendably joined at their lower edges to the corresponding left and right side parts of the front side plate 36, and their vertical ridgeline portions a, a are connected to the bottom plate. Back plate 3 that can be bent freely from 36
3 (not shown), and furthermore, by forming inclined folds f, f reaching the inclined edges 34a, 34a from the lower ends of the vertical ridgeline portions a, a, the unit Base 3
8' and the cover folding plate 40 can be assembled or folded.

[Function] In the first invention, in order to make the book readable, as shown in FIG.
By sliding 7c forward, the mountain fold piece 1
7a is a hollow triangular protuberance on the side to prevent slipping 1
9, and conversely to make it portable, as shown in FIG. The piece 17a is in a flat state.

In the second invention, in order to make the book readable, the bottom plate 36 is
When the sliding piece 37c is slid forward at the top, the mountain-folded piece 37a bulges in a triangular shape with hollow sides to form a non-slip member 39, and raises the vertical ridgeline portions a, a of the left and right side plates 34, 34. When raised, the side plates 34, 34 form straight sloped edges 34c, 34c on their upper end surfaces.On the other hand, in order to make them portable, the raised mountain-folded pieces 37a are attached to the bottom plate 36, as shown in FIG. When pushed down, the sliding piece 37c slides backward, the mountain folded piece 37a becomes flat, and the left and right side plates 34,
34 is pushed forward and bent from the inclined creases f, f, and folded onto the bottom plate 36, the side plates 34, 34 also become flat.

In the third aspect of the present invention, in order to make the book readable, as shown in FIG. It is covered with a bending plate 40,
In order to make it portable, as shown in FIG.
When the raised mountain-folded piece 37a is pushed up and down on the bottom plate 36, and the left and right side plates 34, 34 are bent at the inclined folds f, f and folded onto the bottom plate 36, it becomes flat, and the covering folded plate 40 is also inclined. When the wall portion 44 and the vertical wall portion 43 are folded onto the bottom plate portion 42, they become flat.

[Example] (First Example of the First Invention) Figures 1 to 4 show the first example of the first invention, and are made of a thin plate material such as plastic or cardboard. It is assembled from a molded material 11 consisting of. As shown in FIG. 2, the forming material 11 is formed by forming a truncated chevron-shaped portion 12 into a central back plate 13 and side plates 14 on both sides by hanging two bending lines a and a from both ends of the truncated portion. A connecting piece 14a that can be bent inwardly or outwardly at right angles is formed at the lower end of each side plate 14, and a vertically long rectangular portion 15 is integrally or jointly formed at the lower end of the back plate 13 along a bending line b. The vertically long rectangular portion 15 is bent along the line c.
The upper bottom plate 16 and the lower folded part 17 are formed by bending the lower folded part 17 along two folding lines d and e (the folding line e is bent in the opposite direction to the folding line d). For convenience, perforations are used to indicate the shape of the fold, but it goes without saying that either a normal convex or concave shape may be used).
It is divided into a sliding piece 7a and a sliding piece 17c. Stopper holes 14b, 14b, 16b, 16b are bored near the tips of the connecting pieces 14a, 14a of the left and right side plates 14, 14, and near the center of both side edges of the bottom plate 16, and the sliding pieces 17c of the folded portion 17 Elongated holes 17b, 17b for sliding guide, which are long in the front-rear direction, are bored in both side edges. The assembly of the lectern 18 using this forming material 11 is as shown in FIGS. 1 and 2.
The lower folded portion 17 is folded over the bottom plate 16 to form a triangular non-slip member 19 with a hollow side surface using the mountain folded piece 17a, and the truncated chevron portion 12 is raised up, and the side plates 14, 14 on both sides are raised. By bending forward, sloped edges 14c, 14c are formed with a downward slope of about 45 degrees to the front. In this way, a planar standing wall is formed, and the side plates 14, 14 on both sides are
Connect the inner bent connecting pieces 14a, 14a at the lower end of the bottom plate 1.
6, the rear part is fixed as necessary, and the connecting piece 14a, the stopper holes 14b, 16b of the bottom plate 16, and the elongated hole 17 of the folded part 17 are attached to the front part on both sides.
The assembly is completed by fixing with arbitrary fasteners 10, 10, such as split pins or hooks, which are passed through b. As shown in FIG. 3, the assembled lectern 18 is constructed by sliding the sliding piece 17c forward to form a non-slip member 19 having the shape described above, and leaning against the sloped edges 14c, 14c of the side plates 14, 14. The lower end of the hung book B is supported by the anti-slip 19, making it ideal for reading.
Stand books at an angle. When carrying the book reading stand assembled in this way, as shown in FIG. Carry it by inserting books, notebooks, etc. into the bottom of B.

(Second Embodiment of the First Invention) FIG. 5 shows a second embodiment of the first invention, in which the bottom plate 26, the left and right side plates 24, 24, and the back are made of plastic injection molding or the like. The plate 23 and the folded portion 27 are integrally molded. The folded portion 27 is fastened by folding it from the crease c, stacking it on the bottom plate 26, and inserting a long hole 27b drilled in the sliding piece 27c and a fastening hole 2 drilled in the bottom plate 26.
It is fastened with an arbitrary fastening tool 10 such as a cotter pin or a hook passed through 6b, so that as the sliding piece 27c is slid back and forth, the mountain-folded piece 27a becomes raised or flattened. Although not shown, the stopper hole drilled in the sliding piece 27c and the bottom plate 2
By using the elongated hole drilled in 6, the sliding piece 27 can be attached to the optional fastener 10 that is passed through the elongated hole.
It is also possible to fasten the plate c and slide it back and forth.Also, without forming the back plate 23, it is possible to bend the rear edges of the left and right side plates 24, 24 inward so that their respective vertical ridge lines Of course, it is also possible to join the outside edges together.

(First embodiment of the second invention) FIGS. 6 and 7 show a first embodiment of the second invention, in which a molded material 31 made of a thin plate material such as plastic or cardboard It is assembled from The molding material 31 has basically the same shape as the molding material 11 shown in FIG.
The major difference is that the left and right side plates 34, 34 are formed with inclined folds f, f for folding from the lower ends of the vertical ridges a, a to approximately the center of the inclined edges 34c, 34c. , the connection pieces 34a, 34a at the lower ends of both side plates 34, 34 are bent outward. Assembling the lectern 38 using this forming material 31 involves folding the lower folded portion 37 onto the bottom plate 36 to form a hollow triangular anti-slip 39 on the side surface, and to raise the truncated chevron portion 32 upward. The side plates 34, 34 on both sides are bent forward while the side plates 34, 34 on both sides are bent forward to form a planar standing wall having sloped edges 34c, 34c with a downward slope toward the front. 34a is fixed to the bottom plate 36 at the rear part as it is or as appropriate as required, and at the front parts on both sides, connecting pieces 34a,
The assembly is completed by slidably fixing with appropriate fasteners 10, 10 such as cotter pins or hooks passed through the fixing holes 34b, 36b of the bottom plate 36 and the elongated hole 37b of the folded portion 37. To use the assembled bookstand 38, slide the sliding piece 37c forward to form a non-slip 39 of the shape described above, and place the upper part of the back of the book on the upper edge of the back plate 33 (not shown). While leaning against it, the cover of the book is placed on the left and right side plates 34,
34, the lower end of the book is supported by a non-slip member 39, and the book is stood diagonally at about 45 degrees, which is optimal for reading. When the book is placed upright, press the upper edge of the back plate 33 backwards and press the side plate 3.
Since the vertical ridges a and a of 4 and 34 are in an upright state, the side plates 34 and 34 are never bent at the inclined folds f and f, and are not only stably supported but also able to absorb the load of books. Even when the side plates 34,
This is effective in preventing flattening of the 34 due to extreme stress, reducing the risk of breakage, and maintaining durability. When carrying this device, as shown in FIG. 6, the mountain-folded pieces 37a are pushed down to the bottom plate 36 to make it flat, and the upper edges of the back plate 34 are pressed downward to tilt the side plates 34, 34. The back plate 33 and both side plates 34 are spread outward from the eyes f and f onto the bottom plate 36.
34 is folded into a planar hexagonal shape to make it into a small and flat state convenient for carrying.

(Second Embodiment of the Second Invention) Figures 8 to 11 show a second embodiment of the second invention, which is a molded material made of a thin plate material such as plastic or cardboard. It is assembled from 51. The molding material 51 has two bending lines a and a placed at appropriate intervals near the center of the upper horizontally long rectangular part, and extends from the apex of each bending line a to the lower inner corner of the horizontally long rectangular part. A vertically long rectangular back plate 5 in the center with diagonal bending lines g and g.
3. Triangular side plates 54, 54 formed on the left and right sides of the outside ridge line a, and each side plate 54.
A triangular extension ear piece 5 extending further outward from the
5, 55, and bend lines f, 55 at a predetermined elevation angle θ from the lower end of each bend line a so that they can be folded as described later. f' is formed in a straight line so as to intersect the bending lines g, g, and the left and right side plates 5
Joint pieces 54a, 54a which can be bent inward are extended at the lower ends of 4 and 54 through the bending line, and the lower end of the back plate 53 is bent into a truncated mountain shape through the bending line b. The lower part of the back plate 53, which is connected so that it can be bent, is connected to the bottom plate 56 either integrally or separately (not shown), and this lower part is connected to the upper bottom plate 56 along the bending line c.
and a lower folded portion 57, and the lower folded portion 57 is further divided into a mountain folded piece 57a and a sliding piece 57c by two bending lines d and e. Connection pieces 54a, 5 of the side plates 54, 54
Stop holes 54b, 54b are formed on the outer side of 4a, and a connection piece 54 is formed in the bottom plate 56 along an imaginary line extending from the bending lines a, a (double-dashed line in the figure).
It is preferable that the stop holes 56b, 56b, which correspond to the above-mentioned stop holes 54b, 54b, be drilled when the corresponding lower edges 54a' of the a, 54a are substantially aligned; It is not necessarily necessary that the lower edges 54a' of the pieces 54a coincide; in short, as will be described later, the connection pieces 5
4a, 54a may be configured to be able to be fixed onto the bottom plate 56 at a desired opening degree. Further, a diverging cut portion of an appropriate width may be formed at the separated portion between the lower edges 54a', 54a' of the connecting pieces 54a, 54a and the bottom plate 56. Furthermore, the sliding piece 5 of the folded piece portion 57
7c has a long hole 57 for sliding guide that is long in the front and back direction.
b, 57b are bored at predetermined positions so that the center line coincides with the stop hole 56b. This forming material 5
1, as shown in FIG.
Form a non-slip member 59 with a hollow triangular shape on the side surface at point a, bend the back plate 53 along the bending line b, bend the left and right side plates 54, 54 forward, and bend the extension tabs 55, 55 on both sides outward. By bending it so as to protrude into an ear shape, a vertical wall having sloped edges 54c, 54c that slope downward from the front is formed, and the front portions of the connecting pieces 54a, 54a, which are bent inward at the lower ends of the left and right side plates 54, 54, are bent. The sliding piece 57c that has been folded up in advance onto the bottom plate 56 is overlapped with each set of stopper holes 54b, 56b (the ninth
(see figure) and a suitable fastener 10, such as a cotter pin or hook, which is passed through the long hole 57b, to slidably fasten it to complete the assembly.
The lectern 58 assembled in this way is
As shown in Figure 0, the sloped edges 54 of the side plates 54, 54
c, prevent the bottom edge of the book leaning against 54c from slipping 5
9 to stand the book upright at an angle of approximately 45 degrees, which is optimal for reading, as in the known upright method.
c, 54c can hold the side plates 54, 54 in a flat plane with the extended tabs 55, 55 folded outward, and hold the book B in a stable position. It is convenient because it can be used to fasten the pages of a book together with the cover. When carrying the book reading stand, as shown in FIGS. 8 and 11, the mountain-folded pieces 57a forming the anti-slip 59 are pushed down into a flat state onto the bottom plate 56 and folded, and the side plates 57 of each set of left and right are folded. After raising the extension lug 54 so that the and extension lug 55 form the same plane, the side plate 54 and the extension lug 55 are raised.
The folding operation is extremely simple because it can be folded by pressing downward from the bending lines f and f' so that they overlap and form a flat object with a thin bulk. It is reliable and can be made into a chevron-shaped, elegant and convenient appearance. As shown in FIG. 8, on this lectern 58, if necessary, a bendable photographing piece 61 is attached near the center of the sliding piece 57c of the folded portion 57, and a non-slip 59 If necessary, easily insert page holding pieces 60, 6 on both sides of the front rising part forming the page.
0 can be fixed and attached so that it can rotate freely.

(Embodiment of the third invention) FIGS. 12 and 13 show an embodiment of the third invention, in which a unit base 38' is covered with a covering folding plate 41. This makes it convenient for standing large books etc. upright or for leaning thin papers. The unit base 38' is connected to the sixth unit base 38'.
Substantially the same lectern 38 as shown in the figures and FIG. 7 is used. The cover folding plate 40 is connected to the unit base 3
A bent opening edge 41 (hereinafter simply referred to as "opening edge 41") for wrapping is formed so as to surround the anti-slip 39 of 8'.
) is formed at the front end, a standing wall part 43 that rises at the rear of the bottom plate part 42 along a bending line h, and a bending line i that is continuous with the standing wall part 43 and has a bending line i on the upper edge.
A ridge line consisting of is formed and further the base 3 is
A sloped wall portion 44 that slopes down along the downwardly sloped edges 34a, 34a of 8′, and a bending line j at the end of the sloped wall portion 44.
It is composed of a fold-out piece 45 which hangs down through the center of the fold-out piece 45 and has notches 45a, 45a formed near the center thereof to sandwich the side plates 34, 34 of the unit base 38'. The opening edge 41 is a rising piece 41a that is bent following the front part of the bottom plate part 42.
and the inner presser piece 41b, which is bent inward at the crease m and is configured to be inclined, are joined together using a stapler or other suitable joining tools 46, 46, and the non-slip member 39 of the unit base 38' is attached at the center thereof. It is designed so that it can be opened for intervening purposes. When used as a bookstand, the anti-slip 39 is formed at the tip of the unit base 38' with the left and right side plates 34, 34 upright, and the anti-slip 39 is wrapped around the opening edge in the front center of the folded plate. 41, and the unit base 3
The bottom plate 36 of 8' is wrapped around the bottom plate part 42 of the bent plate 40.
The vertical wall portion 43 is raised along the upper surface, and the inclined wall portion 4
Although not shown, the upper half of the book is placed against the slanted wall 44, and the non-slip 39
By supporting the lower end of the book with the opening edge 41 that embraces the opening edge 41, the book can be stood at an angle of about 45 degrees, which is optimal. The unit base 38' exhibits sufficient strength against the load of books due to its vertical ridgelines, but in particular, the unit base 38' with two vertical ridgeline portions a, a is capable of supporting books even when constructed of thin material. The standing holding force of the unit base 38' is extremely large, and the bottom plate 36 of the unit base 38',
Most of the upper edges of the back plate 33 and side plates 36, 36 are covered, and the bending strength of the upper edge of the back plate 33 and its side plates 34, 34 can be significantly increased in the overlapping state. Therefore, even if a narrow unit base 38' is used, by wrapping it as a core material and maintaining a stable combination of the entire present invention, books etc. can be stably stored without fear of destruction. It can be supported. In addition, when carrying this unit, as shown in FIG. 13, the unit base 38' from which the cover folding plate 40 has been removed has a protruding mountain-fold piece 37a for forming a non-slip 39 at the tip of the unit base 38' on the bottom plate 36. At the same time, by pressing the upper edge of the back plate 33 downward, the side plates 34, 34 are extended outward at the inclined folds f, f, and placed on the bottom plate 36. It can be folded into a flat state. In addition, the covering folding plate 40 is a flat unit base 38' placed on the bottom plate part 42, which is completely folded by wrapping it with a standing wall part 43, a diagonal wall part 44, and a folding piece 45,
can be made convenient.

[Effects of the Invention] As detailed above, the present invention has the following excellent effects.

In the case of the first invention, when the mountain-folded piece forming the anti-slip is pushed down onto the bottom plate, the sliding piece slides backward and the mountain-folded piece becomes flat, so that the anti-slip can be used when carrying the device. It won't crush you.

Ballpoint pens, pencils, and other rod-like materials can be inserted into the hollow portion of the anti-slip member having a hollow chevron shape on its side, so that several rod-like materials such as ballpoint pens, pencils, etc. can be connected in parallel for stable use.

In the second invention, when the mountain-folded piece forming the anti-slip is pushed down onto the bottom plate, the sliding piece slides backward and the mountain-folded piece becomes flat.
By folding the left and right side panels along the slanted creases and folding them onto the bottom plate, the side panels also become flat, making it possible to downsize the product extremely quickly, making it extremely convenient for carrying and storage, and for an attractive appearance. It can also be made graceful.

In the case of the third invention, the raised mountain fold portion for forming a non-slip of the unit base from which the covering folding plate has been removed is pushed down onto the bottom plate, and the left and right side plates are also pushed outward by the inclined folds. When it is expanded and folded, it becomes flat, and it can be further folded so that the folded unit base is sandwiched between the diagonal wall portion, the vertical wall portion, and the bottom plate portion of the covering folding plate. As a result, the entire device can be made compact in a short period of time, making it extremely convenient for both portability and storage.

[Brief explanation of the drawing]

1 to 4 show a first embodiment of the first invention, in which FIG. 1 is a perspective view showing the whole, FIG. 2 is a plan view showing the developed molded material, and FIG. The figure is a side view showing the book in an inclined state, FIG. 4 is a perspective view showing the book being carried, FIG. 5 is a partially cutaway perspective view showing the second embodiment of the first invention, FIG. 7 shows the first embodiment of the second invention, in which FIG. 6 is a perspective view showing a state in the middle of folding, FIG. 7 is an exploded perspective view showing the assembly process, and FIGS. Fig. 11 shows a second embodiment of the second invention, Fig. 8 is a perspective view showing the whole, Fig. 9 is a plan view showing the unfolded molding material, and Fig. 10 shows the book in an inclined position. FIG. 11 is a side view showing the folded state, FIG. 11 is a perspective view showing the partially folded state, FIGS. 12 and 13 show an embodiment of the third invention, and FIG. 12 is the assembled state. FIG. 13 is a perspective view showing a state in the middle of folding, FIG. 14 is a perspective view showing a conventional lectern, and FIG. 15 is a perspective view of the same lectern being assembled. FIG. 13, 23, 33, 53... back plate, 14, 2
4, 34, 54...Side plate, 14c, 24c, 34
c, 54c...gradient edge, 16, 26, 36, 56
... Bottom plate, 17, 27, 37, 57 ... Folded portion, 17a, 27a, 37a, 57a ... Mountain fold piece, 17c, 27c, 37c, 57c ... Sliding piece, 19, 29, 39, 59 ...Non-slip, 3
8'... Unit base, 40... Covering folding plate, 41
...bending opening edge.

Claims (1)

[Claims] 1. On the bottom plate, left and right side plates having sloped edges with a downward slope toward the front are erected by any method,
In a lectern with a non-slip formed in the front of the bottom plate, in order to form the non-slip on the front edge of the bottom plate so that it can be bent freely, a mountain fold line that becomes the top ridgeline that runs in the left and right direction is adjacent to the front edge of the bottom plate. A sliding piece stacked on the bottom plate is connected to the rear edge of the mountain folded piece, and a longitudinally long elongated hole is formed in one of the sliding piece and the bottom plate. A lectern, characterized in that the mountain-folded piece is slidably fixed by a suitable fastener through a fastening hole bored in the other side, so that the mountain-folded piece can be raised and lowered. 2. The lectern according to claim 1, wherein the sliding piece is sandwiched between the connecting pieces formed on the lower edge pieces of the left and right side plates and the bottom plate. 3. A lectern in which left and right side plates having sloped edges that slope downward toward the front are erected on a bottom plate, and a non-slip member is formed in front of the bottom plate, and the non-slip member is formed on the front edge of the bottom plate so that it can be bent freely. In order to do this, a mountain-folded piece is formed with a mountain-fold line that is a top ridgeline that runs in the left-right direction adjacent to the front edge of the mountain-folded piece, and a sliding piece that overlaps the bottom plate is attached to the rear edge of the mountain-folded piece. The sliding piece and the bottom plate are slidably fastened with an appropriate fastening tool through a longitudinally long long hole drilled in one side and a stopper hole drilled in the other, and the mountain-folded piece is undulated. The left and right side plates outside the vertical ridge are bendably joined at their lower edges to the bottom plate, and their vertical ridges are connected via a back plate which bendably stands from the rear end of the bottom plate. A bookstand characterized in that it can be folded freely without any interference, and can be folded into a flat shape by forming an inclined fold extending from the lower end of the vertical ridgeline to approximately the center of the sloped edge. 4. The lectern according to claim 3, wherein the sliding piece is sandwiched between the connecting pieces formed on the lower edge pieces of the left and right side plates and the bottom plate. 5. The left and right side plates have triangular or other arbitrarily shaped extension tabs extending outward from the sloped edges thereof, such that the extension tabs are bendable, and the extension tabs have folds that extend linearly to the sloping folds. A lectern according to claim 3 or 4. 6 On the bottom plate, left and right side plates having sloped edges with a downward slope toward the front are erected, and a unit base with a non-slip formed in the front of the bottom plate and the non-slip of the unit base are enclosed in a surrounding shape. The bottom plate has a bent opening edge at its front end, and the cover folding plate has a bending line formed at the upper end of a standing wall that is bendably connected to the rear to form a slanted wall. In order to form the anti-slip part of the unit base on the front edge of the bottom plate so that it can be bent freely, a mountain fold line is attached adjacent to the folded front edge and serves as a top ridge line along the left and right direction. A mountain-folded piece is formed, and a sliding piece stacked on the bottom plate is connected to the rear edge of the mountain-folded piece, and a longitudinally long elongated hole is formed in one of the sliding piece and the bottom plate, and a long hole is bored in the other side. The mountain-folded pieces are slidably fastened with appropriate fasteners through the provided fastening holes, so that the mountain-folded pieces can be raised and lowered, and the left and right side plates outside the vertical ridge line of the unit base are bent at their lower edges to the bottom plate. They are joined together freely, and their vertical ridgeline portions are bendable with or without a back plate that stands upright from the bottom plate, and furthermore, from the lower end of the vertical ridgeline portions to approximately the center of the sloped edge. 1. A lectern, characterized in that the unit base and the covering folding plate are configured to be assembled or folded by forming an inclined fold that reaches a portion. 7. The lectern according to claim 6, wherein the sliding piece is sandwiched between the connecting pieces formed on the lower edge pieces of the left and right side plates, respectively, and the bottom plate.