CN219515715U - Desk and chair with inserted feet and easy-to-detach book hopper - Google Patents

Abstract

The desk comprises a desk and a chair, wherein the desk comprises a left desk supporting leg, a right desk supporting leg, a book hopper and a desk plate assembly, the chair comprises a chair supporting leg, the chair supporting legs are at least left and right, the rear parts of the left and right chair supporting legs are respectively provided with an extension leg which extends backwards, when the desk is used, the two extension legs of the chair are arranged between the two desk supporting legs of the desk positioned at the rear part of the desk, a chair seat plate is arranged on the chair supporting legs, a backrest plate capable of being obliquely adjusted is arranged at the rear part of the chair seat plate, the book hopper and the desk plate assembly are detachably arranged on the left and right desk supporting legs, and the book hopper and the desk plate assembly which are detached can be taken down from the two desk supporting legs to vacate the space above the two desk supporting legs.

Description

Desk and chair with inserted feet and easy-to-detach book hopper

Technical Field

The utility model relates to a desk and a chair with a spliced footing and an easily detachable book hopper, belonging to the field of teaching equipment.

Background

Students have a rest on a desk directly after noon break in school in a traditional mode, and the quality of noon break can be influenced when students lie on the desk. Therefore, the inventor applied for Chinese patent 202111167198.9, the patent name is "leisure table and chair", which comprises a foot shared by a table and a chair, wherein a group of table supporting feet are arranged on the front surface of the foot, a chair supporting foot is arranged on the rear surface of the foot, a table plate is arranged on the table supporting feet, a chair plate is arranged on the chair supporting feet, a backrest plate capable of being obliquely adjusted is arranged on the rear part of the chair plate, at least two table supporting feet are arranged on the left side and the right side, a lying plate is arranged between the two table supporting feet, and the lying plate, the chair plate and the backrest plate form a leisure bed. When the desk is used in classrooms, a plurality of leisure desk and chairs are usually placed in parallel front and back, so when the back board of the previous leisure desk and chair is inclined to fall down, the desk legs, the desk boards and the book hoppers of the next leisure desk and chair are required to be lifted up first, enough space is reserved under the book hoppers, the back board can be lifted up when the desk is at rest each time, the desk is required to fall down when the desk is in class after rest, and the desk legs, the desk boards and the book hoppers are lifted up through continuous shaking handles, so that the desk is time-consuming and labor-consuming, the operation is very troublesome, and after long-term use, the lifting mechanism is easy to break, and the service life of the desk and chair is influenced; in addition, after the desk plate and the book hopper are lifted, the head of a student lying on a leisure desk and chair in front faces to the lower part of the book hopper, the head space is small, and the student can feel depressed and even the resting quality is influenced.

Disclosure of Invention

The utility model aims to overcome the defects of the prior art, and provides the desk and chair with the easily-detached footing plug-in type desk plate and book hopper, which are beneficial to backward tilting of the back plate of the chair positioned in front of a desk, and have the advantages of abundant head space, no sense of depression, full utilization of space in a teaching room, simple structure and convenient operation.

The utility model relates to a desk with a spliced footing and a desk with a detachable book hopper, which comprises the following technical scheme: the desk comprises a desk and a chair, wherein the desk comprises left and right two desk supporting legs and a book hopper and desk plate assembly, the chair comprises at least left and right two chair supporting legs, the rear parts of the left and right two chair feet are respectively provided with an extension foot which extends backwards, when the desk is used, the two extension feet of the chair are arranged between the two desk supporting legs of the desk at the rear part of the desk, a chair seat plate is arranged on the chair supporting legs, a backrest plate capable of being obliquely adjusted is arranged at the rear part of the chair seat plate, the book hopper and the desk plate assembly are detachably arranged on the left and right two desk supporting legs, and the book hopper and the desk plate assembly which are detached can be taken down from the two desk supporting legs to vacate a space above the two desk supporting legs.

The utility model discloses a desk with a detachable bottom foot plug-in type desk plate and a desk plate assembly, which are mainly characterized in that the desk plate and the desk plate assembly are detachably arranged on left and right desk supporting legs, when the desk is used in a classroom, a desk and a chair are usually formed into a group of desk and chair, a plurality of groups of desk and chair are arranged in parallel front and back, when a student is in a class, the desk plate assembly and the desk plate assembly are arranged on the left and right desk supporting legs in a horizontal state, when the student needs to rest in noon, the desk plate assembly and the desk plate assembly can be detached from the desk supporting legs together, so that a space is reserved between the left and right desk supporting legs and the upper part of the left and right desk supporting legs, a back plate positioned in front of the chair can be inclined backwards (the inclined structure of the back plate of the chair is the prior art), a back plate frame is positioned between the left and right desk supporting legs of the back of the desk, when the student is in a chair, the student is lying on the chair, and the student is leaning on the back, the head is not blocked by the book hoppers and the desk plates of the rear desk, the head space is abundant, the desk and the chair can not feel depressed, the back board can be reclined without pulling the desk and the chair apart by a long distance, thus the inner space of a classroom is fully utilized, in addition, the extension feet at the rear parts of the chair supporting feet of the chair of the front group of desk and chair can be inserted between the desk supporting feet of the desk of the rear group of desk and chair, the extension feet extending backwards support the weight of a human body lying on the chair, the chair is prevented from being reclined, the use is stable and safe, particularly, the extension feet extend between the left and right desk supporting feet below the desk at the rear part, the space below the desk is fully and reasonably utilized, the space in front of and behind the original desk and chair in the classroom is not occupied, the effective arrangement of the desk and chair in the classroom is ensured, the extension feet also play a limiting role on the front and rear arrangement of the desk and chair, the desk and the chair are orderly arranged in front and back.

Further, at least one table supporting leg is provided with a hook or a hanging part, at least one of the left side and the right side of the book hopper and the table plate assembly is provided with a hanging part or a hook, and the book hopper and the table plate assembly detached from the two table supporting legs can be hung on the at least one table supporting leg to be in an upright position; the erected book hopper and table plate assembly is positioned outside the at least one table supporting leg.

Further, the hanging piece or the hanging hook of the book hopper and the desk plate assembly is arranged at the bottom of the book hopper.

Further, the top of every table supporting legs is provided with the bracing piece that extends from front to back, the couple sets up on the bracing piece, be provided with on book fill and the table subassembly and hang by the piece, both sides are provided with two on the bracing piece around, book fill and the table subassembly are provided with two and hang by the piece or book fill and the table subassembly hang by the piece for the long hanging by the piece that extends along fore-and-aft direction, or the top of every table supporting legs is provided with the bracing piece that extends from front to back, the bracing piece is used as hanging by the piece, book fill and table subassembly are provided with the couple, or book fill and table subassembly are provided with two couples around both sides.

Further, the top of every table supporting legs is provided with the bracing piece that extends from beginning to end, the detachable connection structure of table supporting legs with book end and table subassembly is including setting up locating hole or reference column on the bracing piece and setting up reference column or locating hole in the table bottom, under the assembled condition, the table supporting legs with the reference column on one of the table is in the joint with the locating hole on another, will book end and table subassembly are located and are installed on the table supporting legs, or the top of every table supporting legs is provided with the bracing piece that extends from beginning to end, the detachable connection structure of table supporting legs with book end and table subassembly is including setting up location arch or constant head tank in the bracing piece and setting up constant head tank or the location arch in the table bottom, the constant head tank extends along the fore-and-aft both ends and seals, under the assembled condition, the location arch on one of table supporting legs with the table is installed in the constant head tank on another, will book end and table subassembly are located and are installed on the supporting legs.

Further, at least one of the table support legs is provided with a sliding groove or a sliding rail, the bottom of the book hopper is provided with a sliding rail or a sliding groove which is in sliding fit with the sliding groove or the sliding rail on the table support leg, the sliding rail or the sliding rail on the book hopper and the table plate component detached from the two table support legs can be inserted into the sliding groove or the sliding rail on the table support leg from the upper part and can slide downwards to be in an upright position, the book hopper and the table plate component are kept in the upright position by the mutually matched sliding groove and sliding rail, and the upright book hopper and the table plate component are positioned on the outer side of the table support leg.

Further, a slide rail or a slide groove at the bottom of the book hopper is provided with a limiting piece for limiting the sliding position of the book hopper and the desk plate assembly.

Further, the top of every table supporting legs is provided with the bracing piece that extends from beginning to end, the detachable connection structure of table supporting legs with book end and table subassembly is including setting up locating hole or reference column on the bracing piece and setting up reference column or locating hole in the table bottom, under the assembled condition, the table supporting legs with the reference column on one of the table is in the joint with the locating hole on another, will book end and table subassembly are located and are installed on the table supporting legs, or the top of every table supporting legs is provided with the bracing piece that extends from beginning to end, the detachable connection structure of table supporting legs with book end and table subassembly is including setting up location arch or constant head tank in the bracing piece and setting up constant head tank or the location arch in the table bottom, the constant head tank extends along the fore-and-aft both ends and seals, under the assembled condition, the location arch on one of table supporting legs with the table is installed in the constant head tank on another, will book end and table subassembly are located and are installed on the supporting legs.

Further, the extension foot set up in the inboard of chair supporting legs, extension foot and chair supporting legs fixed connection or swing joint, swing joint be the inboard adapter sleeve of chair supporting legs, sleeve pipe and chair supporting legs fixed connection, the last jack that has of sleeve pipe, the one end of extension foot inserts in the sleeve pipe, has the pinhole on the extension foot, passes the jack by the bolt and matches with the pinhole.

Further, two table supporting legs about set up the service creeper between, the front portion of table supporting legs sets up the crosspiece, the inner wall of table supporting legs sets up the spacer pin, service creeper and crosspiece swivelling joint through rotating device, with spacer pin spacing contact when the service creeper falls down, rotating device includes that one side system at the service creeper has the rotor, has the connection piece on the crosspiece, connection piece and rotor swivelling joint through the pivot.

Drawings

FIG. 1 is a perspective view of a chair with extension legs inserted between the legs of a rear desk and hooks provided on the bottom of the bucket;

FIG. 2 is a perspective view of the chair extension leg inserted between the rear desk support legs and the book well and table hanging from the support bar via the hanger;

FIG. 3 is a perspective view of the chair extension leg inserted between the rear desk support legs and the book well and table hanging from the hanger via the hanger;

FIG. 4 is a perspective view of a chair extension leg inserted between rear desk legs and a chute provided on the outer wall of the desk legs;

FIG. 5 is a perspective view of the book hopper and the table plate standing on the outer wall of the table supporting leg and being matched with the sliding groove by the sliding rail;

FIG. 6 is a perspective view of a bottom of the hopper with a slide rail and a locating projection;

FIG. 7 is a perspective view of the chair extension leg inserted between the rear desk support legs and the creeper standing between the desk support legs;

FIG. 8 is a perspective view of the chair extension inserted between the rear desk legs and the creeper being angled between the desk legs;

fig. 9 is an enlarged partial schematic view at a of fig. 7.

Reference numerals in the schematic drawings illustrate:

1. a table support leg; 2. a book hopper; 3. a table plate; 4. a hook; 5. a hanging piece; 6. a support rod; 7. positioning holes; 8. positioning columns; 9. positioning the bulge; 10. a positioning groove; 11. a chute; 12. a slide rail; 13. a limiting piece; 15. a chair support leg; 16. a chair seat; 17. a backboard; 60. a lying plate; 61. a crosspiece; 62. a limiting pin; 63. a rotating piece; 64. a connecting sheet; a 65 spindle; 70. extending the foot; 71. a sleeve; 72. a pin hole; 73. a bolt.

Detailed Description

The utility model relates to a desk and chair with easily detachable feet, as shown in figures 1-9, comprising a desk and a chair, wherein the desk comprises a left desk supporting leg 1, a right desk supporting leg 1, a book hopper 2 and a desk plate 3, the chair comprises at least two chair supporting legs 15, the rear parts of the left and right chair supporting legs are respectively provided with an extension leg 70 which extends backwards, when the desk is used, the two extension legs of the chair are arranged between the two desk supporting legs 1 of the desk at the rear part of the desk, a chair seat board 16 is arranged on the chair supporting legs 15, a backrest plate 17 which can be obliquely adjusted is arranged at the rear part of the chair seat board, the book hopper 2 and the desk plate 3 are detachably arranged on the left and right desk supporting legs 1, and the book hopper 2 and the desk plate 3 which are detached can be taken off from the two desk supporting legs 1 to vacate space above the two desk supporting legs. The desk and chair are mainly characterized in that the book bucket 2 and the desk plate 3 assembly are detachably arranged on the left and right desk supporting legs 1, when the desk and the chair are used in classrooms, a desk and a chair are usually formed into a group of desk and chair, a plurality of groups of desk and chair are arranged in parallel front and back, during normal school, the book bucket 2 and the desk plate 3 assembly are horizontally arranged on the left and right desk supporting legs 1 together, when students need to have noon break, the book bucket 2 and the desk plate 3 assembly can be detached from the desk supporting legs 1 together, a space is reserved between the left and right desk supporting legs and at the upper part, the back board 17 of the front chair can be inclined backwards (the inclined structure of the back board of the chair is the prior art), the back board 17 is arranged between the left and right desk supporting legs 1 of the back desk, when the students lie on the chair, the heads rest on the back board 17, the heads are not blocked by the book bucket 2 and the desk plate 3 of the back desk, the head space is abundant, the desk and the chair can not feel depressed, the backboard 17 can be reclined without pulling the desk and the chair apart by too long distance, thereby fully utilizing the inner space of the classroom, in addition, the extension feet 70 at the rear part of the chair supporting feet 15 of the chair of the front group of desk and chair can be inserted backwards between the desk supporting feet 1 of the desk of the rear group of desk and chair, the extension feet extending backwards support the weight of the human body lying on the chair, avoid the chair from being reclined, and are stable and safe to use, in particular, the extension feet 70 extend between the left and right desk supporting feet 1 below the desk of the rear side, fully and reasonably utilize the space below the feet, occupy the front and rear space of the original desk and chair in the classroom, ensure the effective arrangement of the desk and chair in the classroom, and the extension feet 70 also play a limiting role on the front and rear arrangement of the desk and chair, the desk and the chair are orderly arranged in front and back.

Further, at least one table supporting leg 1 is provided with a hook 4 or a hanging piece 5, at least one of the left side and the right side of the book block 2 and the table plate 3 assembly is provided with the hanging piece 5 or the hook 4, and the book block 2 and the table plate 3 assembly detached from the two table supporting legs 1 can be hung on the at least one table supporting leg 1 to be in an upright position; the erected book block 2 and table 3 assembly is located outside the at least one table support leg 1.

Further, a hanging piece 5 or a hanging hook 4 of the assembly of the book hopper 2 and the desk plate 3 is arranged at the bottom of the book hopper 2.

Further, the top of each desk supporting leg 1 is provided with a supporting rod 6 extending back and forth, the hooks 4 are arranged on the supporting rod 6, the assembly of the book hopper 2 and the desk plate 3 is provided with hanging parts 5, two hooks 4 are arranged on the front side and the back side of the supporting rod, two hanging parts 5 are arranged on the front side and the back side of the assembly of the book hopper 2 and the desk plate 3, or the hanging parts of the assembly of the book hopper 2 and the desk plate 3 are long hanging parts extending along the front and the back direction, or the top of each desk supporting leg 1 is provided with a supporting rod 6 extending back and forth, the supporting rod is used as the hanging parts 5, the assembly of the book hopper 2 and the desk plate 3 is provided with hooks 4, or the front side and the back side of the assembly of the book hopper 2 and the desk plate 3 are provided with two hooks 4.

Further, the top of each table supporting leg 1 is provided with a supporting rod 6 extending back and forth, the detachable connection structure of each table supporting leg and each assembly of the book hopper 2 and the table plate 3 comprises a positioning hole 7 or a positioning column 8 arranged on the supporting rod and a positioning column 8 or a positioning hole 7 arranged at the bottom of the table plate 3, in the assembled state, the positioning column on one of the table plates 3 and the positioning column on the other are engaged, the assembly of the book hopper 2 and the table plate 3 is positioned and installed on the table supporting leg 1, or the top of each table supporting leg is provided with a supporting rod 6 extending back and forth, the detachable connection structure of the table supporting leg 1 and the assembly of the book hopper 2 and the table plate 3 comprises a positioning protrusion 9 or a positioning groove 10 arranged on the supporting rod 6 and a positioning groove 10 or a positioning protrusion 9 arranged at the bottom of the table plate 3, in the assembled state, the positioning groove extends along the front and back directions and is closed at the front and back ends, in the assembled state, the assembly of the table supporting leg 1 and the positioning protrusion 9 on the table plate 3 is assembled and the assembly of the table supporting leg 1 and the assembly of the book hopper 2 and the table plate 3 is installed on the positioning protrusion 10.

Further, at least one of the table support legs 1 is provided with a chute 11 or a slide rail 12, the bottom of the book hopper 2 is provided with a slide rail 12 or a slide rail 11 which is in sliding fit with the chute 11 or the slide rail 12 of the table support leg 1, the slide rail or the chute of the book hopper 2 and the table 3 assembly detached from the two table support legs 1 can be inserted into the chute or the slide rail of the table support leg from above and can slide downwards to be in an upright position, the mutually matched chute 11 and slide rail 12 keep the book hopper 2 and the table 3 assembly in the upright position, and the upright book hopper and the table assembly are positioned outside the table support leg 1.

Further, a sliding rail 12 or a sliding groove 11 at the bottom of the book block 2 is provided with a limiting piece 13 for limiting the sliding position of the book block 2 and desk plate 3 assembly.

Further, the top of each table supporting leg 1 is provided with a supporting rod 6 extending back and forth, the detachable connection structure of each table supporting leg 1 and the assembly of the book bucket 2 and the table plate 3 comprises a positioning hole 7 or a positioning column 8 arranged on the supporting rod 6 and a positioning column or a positioning hole arranged at the bottom of the table plate 3, in the assembled state, the positioning column 8 on one of the table plates 3 and the positioning column 8 on the other table plate are engaged, the assembly of the book bucket 2 and the table plate 3 is positioned and installed on the table supporting leg 1, or the top of each table supporting leg is provided with a supporting rod 6 extending back and forth, the detachable connection structure of the table supporting leg 1 and the assembly of the book bucket 2 and the table plate 3 comprises a positioning protrusion 9 or a positioning groove 10 arranged on the supporting rod 6 and a positioning groove or a positioning protrusion arranged at the bottom of the table plate 3, in the assembled state, the positioning groove extends along the front and back directions and is closed at the front and back ends, in the assembled state, the assembly of the table supporting leg and the positioning protrusion 9 on one of the table plate is assembled and the assembly of the table supporting leg is installed on the positioning protrusion 9 on the other table supporting leg 2 and the assembly of the book bucket 2 and the table plate 3.

Further, the extension leg 70 is disposed at the inner side of the chair support leg 15, and is fixedly connected or movably connected with the chair support leg, the movable connection is an inner side connecting sleeve 71 of the chair support leg 15, the sleeve is fixedly connected with the chair support leg, a jack is formed on the sleeve, one end of the extension leg is inserted into the sleeve, a pin hole 72 is formed on the extension leg, and the plug 73 passes through the jack to be matched with the pin hole 72.

Further, a lying plate 60 is arranged between the left table supporting leg 1 and the right table supporting leg 1, a crosspiece 61 is arranged at the front part of the table supporting leg 1, a limiting pin 62 is arranged on the inner wall of the table supporting leg, the lying plate is rotationally connected with the crosspiece 61 through a rotating device, the lying plate 60 is in limiting contact with the limiting pin 62 when being laid down, the rotating device comprises a rotating piece 63 which is arranged on one side of the lying plate, a connecting piece 64 is arranged on the crosspiece, and the connecting piece 64 is rotationally connected with the rotating piece 63 through a rotating shaft 65.

Claims (10)

1. Footing plug-in type desk and chair with book hopper easy-to-detach, its characterized in that: the desk comprises a desk and a chair, wherein the desk comprises left and right two desk supporting legs and a book hopper and desk plate assembly, the chair comprises at least left and right two chair supporting legs, the rear parts of the left and right two chair feet are respectively provided with an extension foot which extends backwards, when the desk is used, the two extension feet of the chair are arranged between the two desk supporting legs of the desk at the rear part of the desk, a chair seat plate is arranged on the chair supporting legs, a backrest plate capable of being obliquely adjusted is arranged at the rear part of the chair seat plate, the book hopper and the desk plate assembly are detachably arranged on the left and right two desk supporting legs, and the book hopper and the desk plate assembly which are detached can be taken down from the two desk supporting legs to vacate a space above the two desk supporting legs.

2. The foot-insertable desk-and-chair of claim 1 wherein: the book hopper and the table plate assembly detached from the two table support legs can be hung on the at least one table support leg to be in an upright position; the erected book hopper and table plate assembly is positioned outside the at least one table supporting leg.

3. The foot-insertable desk-and-chair of claim 2 wherein: the hanging piece or the hanging hook of the book hopper and the desk plate assembly is arranged at the bottom of the book hopper.

4. A foot-insertable desk and chair according to any one of claims 2 to 3, wherein: the top of every table supporting legs is provided with the bracing piece that extends from beginning to end, the couple sets up on the bracing piece, be provided with on book fill and the table subassembly and hang by the piece, both sides are provided with two on the bracing piece around, both sides are provided with two and hang by the piece or the book fill and the table subassembly hang by the piece for the long hanging by the piece that extends along fore-and-aft direction, or the top of every table supporting legs is provided with the bracing piece that extends from beginning to end, the bracing piece is used as hanging by the piece, book fill and table subassembly are provided with the couple, or both sides are provided with two couples around book fill and the table subassembly.

5. A foot-insertable desk and chair according to any one of claims 2 to 3, wherein: the top of every table supporting legs is provided with the bracing piece that extends from beginning to end, the detachable connection structure of table supporting legs with book hopper and table subassembly is including setting up locating hole or reference column on the bracing piece and setting up reference column or locating hole in the table bottom, under the assembled condition, the table supporting legs with the reference column on one of the table is in the joint with the locating hole on another, will book hopper and table subassembly location is installed on the table supporting legs, or the top of every table supporting legs is provided with the bracing piece that extends from beginning to end, the detachable connection structure of table supporting legs with book hopper and table subassembly is including setting up location arch or the constant head tank of setting up in the table bottom, the constant head tank extends and front and back both ends are sealed, under the assembled condition, the table supporting legs with the constant head tank on one of table is joined in marriage in another, will book hopper and table subassembly location is installed on the table supporting legs.

6. The foot-insertable desk-and-chair of claim 1 wherein: the book hopper and the table plate assembly are arranged on the table support leg, the bottom of the book hopper is provided with a sliding groove or a sliding rail which is in sliding fit with the sliding groove or the sliding rail on the table support leg, the sliding rail or the sliding rail on the book hopper and the table plate assembly which are detached from the two table support legs can be inserted into the sliding groove or the sliding rail on the table support leg from the upper part and can slide downwards to be in an upright position, the mutually matched sliding groove and sliding rail keep the book hopper and the table plate assembly in the upright position, and the book hopper and the table plate assembly after being upright are positioned on the outer side of the table support leg.

7. The foot-insertable desk-chair of claim 6 wherein: the sliding rail or the sliding groove at the bottom of the book hopper is provided with a limiting piece for limiting the sliding position of the book hopper and the desk plate assembly.

8. The foot-insertable desk-chair of claim 6 wherein: the top of every table supporting legs is provided with the bracing piece that extends from beginning to end, the detachable connection structure of table supporting legs with book hopper and table subassembly is including setting up locating hole or reference column on the bracing piece and setting up reference column or locating hole in the table bottom, under the assembled condition, the table supporting legs with the reference column on one of the table is in the joint with the locating hole on another, will book hopper and table subassembly location is installed on the table supporting legs, or the top of every table supporting legs is provided with the bracing piece that extends from beginning to end, the detachable connection structure of table supporting legs with book hopper and table subassembly is including setting up location arch or the constant head tank of setting up in the table bottom, the constant head tank extends and front and back both ends are sealed, under the assembled condition, the table supporting legs with the constant head tank on one of table is joined in marriage in another, will book hopper and table subassembly location is installed on the table supporting legs.

9. The foot-insertable desk-and-chair of claim 1 wherein: the extension foot set up in the inboard of chair supporting legs, extension foot and chair supporting legs fixed connection or swing joint, swing joint be the inboard adapter sleeve of chair supporting legs, sleeve pipe and chair supporting legs fixed connection, the last jack that has of sleeve pipe, the one end of extension foot inserts in the sleeve pipe, has the pinhole on the extension foot, passes the jack by the bolt and matches with the pinhole.

10. The foot-insertable desk-and-chair of claim 1 wherein: the lying board is arranged between the left table supporting leg and the right table supporting leg, a crosspiece is arranged at the front part of the table supporting leg, a limiting pin is arranged on the inner wall of the table supporting leg, the lying board is rotationally connected with the crosspiece through a rotating device, the lying board is in limiting contact with the limiting pin when being laid down, the rotating device comprises a rotating sheet which is arranged on one side of the lying board, a connecting sheet is arranged on the crosspiece, and the connecting sheet is rotationally connected with the rotating sheet through a rotating shaft.