BEAM AND COLUMN CONNECTING STRUCTURE FOR A BED, AND A BED COMPRISING THE SAME

Abstract

A beam and column connecting structure, including an insertion hole on the column, a connector inserted into the insertion hole, and a beam having an end inserted into the connector and being in complete contact with an inner side wall of the connector. A flange is provided around a top side of the connector and abuts against an outer side wall of the column around the insertion hole. A connecting plate is provided inside the end of the beam. At least one screw passes through the column, a bottom wall of the connector, and the connecting plate to fix the column, connector and the beam together.

Description

TECHNICAL FIELD

The present invention relates to the technical field of a bed, and more specifically relates to a beam and column connecting structure for a bed, and a bed comprising the same.

BACKGROUND OF THE INVENTION

According to an existing structure of a bed, a beam and a column of a bed are usually connected through a metal sheet welded to an end of the beam; the end of the beam provided with the metal sheet is placed against the column, and a screw is then used to pass through the metal sheet and the column so as to connect the beam and the column. However, this method of connection has the following disadvantages:

1. Since the metal sheet is projected out of the end of the beam, the beam takes up a certain space during transportation and thus being inconvenient to transport.

2. Since the metal sheet has a considerable thickness, a gap may exist between the beam and the column after installation. Accordingly, if the bed wobbles during use, friction may occur and noise is hence resulted. This problem is particularly worse if the metal sheet is connected to a metal column.

3. Since the beam is threaded to the column through the metal sheet, the beam is not directly in contact with the column. As such, a force bearing point between the two is concentrated only on the screw and the metal sheet, and this way of connection is unstable. External factors like shaking, loading, and impacting may result in excessive force that may loosen the connection between the two, causing instability and safety hazards.

BRIEF SUMMARY OF THE INVENTION

In view of the aforesaid disadvantages now present in the prior art, it is an object of the present invention to provide a beam and column connecting structure for a bed which achieves firm connection and a compact structure; further, a bed comprising said connecting structure is also disclosed.

To achieve the above object, the present invention provides the following technical solutions:

A beam and column connecting structure, comprising a column, a beam, and a connector;

the column is provided with an insertion hole having a shape corresponding to a sectional shape of the beam at an area of the column where the beam is connected with the column; the connector is inserted into the insertion hole; an end of the beam is inserted into the connector;

said connector comprises a bottom wall and four side walls; a top side of the connector is an opening; said end of the beam is inserted into the connector through the opening; an outer side of the bottom wall of the connector has a contour corresponding to a contour of an inner side wall of the column; the outer side of the bottom wall of the connector completely abuts against an inner side wall of the column; an end surface of said end of the beam completely abuts against an inner side wall of the connector; the top side of the connector is provided with a flange protruding outwardly around the opening; the flange completely abuts against an outer side wall of the column surrounding the insertion hole;

said end of the beam inserted into the connector is provided with a connecting plate recessed inside said end of the beam and connecting to inner side walls of the beam; at least one first screw hole is provided through the column at an area of the column corresponding to the bottom wall of the connector, and at least one third screw hole is also provided through the connecting plate of the beam; said at least one first screw hole through the column corresponds to the said at least one third screw hole through the connecting plate; also, the bottom wall of the connector are correspondingly provided with at least one second screw hole or a through opening through which at least one screw passes through; said at least one screw is inserted from the outer side wall of the column passing through said at least one first screw hole, said at least one second screw hole or said through opening, and said at least one third screw hole sequentially, so as to fix the column, the connector and the beam together.

Further, the connector is made of plastic material.

Further, the end surface of said end of the beam abuts an inner side of the bottom wall of the connector, wherein said inner side of the bottom wall of the connector is a flat surface that allows complete contact with the end surface of said end of the beam.

Further, the column is a cylindrical tube; the outer side of the bottom wall is an arc surface which is in complete contact with the inner side wall of the column; the flange around the opening of the connector has two widths bent to be shaped as arcs so that the flange is in complete contact with the outer side wall of the column.

Further, the column is a tube with a shape of a rectangular prism, and the connector is also in a shape of a rectangular prism; the bottom wall of the connector is a flat wall that allows complete contact of the bottom wall with the inner side wall of the column and complete contact with said end surface of said end of the beam.

Further, a center part of each of the bottom wall and the four side walls of the connector is cut out to form an opening; the center part of the bottom wall being cut out form said through opening which said at least one screw passes through.

A bed, comprising a headboard, a footboard, and two side rods spaced apart from each other in parallel each having two ends connected to the headboard and the footboard respectively; each of the headboard and the footboard comprises two columns spaced apart from each other in parallel; each column is configured to be supported against a ground; each of the two side rods comprises at least one beam; wherein in each of the two side rods, two ends of the beam in case only one beam is provided, or two outer ends of two respective beams corresponding to two ends of the corresponding side rod respectively, in case more than one beam are provided, are connected to corresponding columns of the headboard and the footboard respectively; said beam and column connecting structure is used for connection between each outer end of a respective beam and a corresponding column.

Further, each of the two side rods comprises two beams connected in series; the bed also comprises a transverse crossbar, a plurality of transverse rods, a plurality of rails, and at least one leg; said plurality of rails are disposed between two columns of each of the headboard and the footboard; said plurality of transverse rods spaced apart evenly with one another are positioned perpendicularly with respect to the two side rods parallel and opposite to each other, and two ends of each of said plurality of transverse rods are connected to the two side rods respectively; each of two ends of said transverse crossbar is connected to a joint between said two beams of a corresponding side rod; said transverse crossbar is positioned below said plurality of transverse rods; said at least one leg supports said transverse crossbar.

Further, a plurality of fixtures are provided to connect said plurality of transverse rods, wherein each of said plurality of fixtures is used to connect every two adjacent transverse rods; each of the plurality of fixtures comprises a middle stem and two fixing hook portions disposed on two ends of the middle stem respectively; the two fixing hook portions hook on two adjacent transverse rods respectively.

Further, each of the two ends of each of the plurality of transverse rods is provided with a locking part; an inner lateral wall of each corresponding beam corresponding to said one of said two ends of each of the plurality of transverse rods is provided with a plurality of locking grooves spaced apart evenly with one another along a lengthwise direction of the beam; the locking part provided at each of the two ends of each of the plurality of transverse rods is inserted into a corresponding locking groove of a corresponding beam, and thus being located on the inner lateral wall of the corresponding beam; a fixing block is provided at each of the plurality of locking grooves, and an upper end and a lower end of each fixing block are clamped at an upper end and a lower end of a corresponding locking groove; the fixing block fixes a position of a corresponding locking part inserted into the corresponding locking groove.

According to the above technical solutions, the present invention uses a connector in lieu of a metal sheet used in the prior art, for connection between a column and a beam, so that when the column and the beam are connected, an end of the beam connected to the column is inserted into the column instead of abutting against an outer side of the column; accordingly, more stable connection is achieved, and loosening will not be resulted due to shaking or wobbling; further, since the connector is tightly fixed to an interior of the column, no extra space is taken up due to the connection, and no obvious gap exists between the connected column and beam, thereby preventing noise due to friction.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a first perspective view of the beam and column connecting structure according to embodiment 1 of the present invention;

FIG. 2 is a second perspective view of the beam and column connecting structure according to embodiment 1 of the present invention;

FIG. 3 is a first exploded view of the beam and column connecting structure according to embodiment 1 of the present invention;

FIG. 4 is a second exploded view of the beam and column connecting structure according to embodiment 1 of the present invention;

FIG. 5 is a partial sectional view of the beam and column connecting structure according to embodiment 1 of the present invention (where the partial sectional view shows the connection when the connector inserted with the beam is connected with the column);

FIG. 6 is a first perspective view of the beam and column connecting structure according to embodiment 2 of the present invention;

FIG. 7 is a second perspective view of the beam and column connecting structure according to embodiment 2 of the present invention;

FIG. 8 is a first exploded view of the beam and column connecting structure according to embodiment 2 of the present invention;

FIG. 9 is a second exploded view of the beam and column connecting structure according to embodiment 2 of the present invention;

FIG. 10 is a partial sectional view of the beam and column connecting structure according to embodiment 2 of the present invention (where the partial sectional view shows the connection when the connector inserted with the beam is connected with the column);

FIG. 11 an exploded view of the beam and column connecting structure according to embodiment 3 of the present invention;

FIG. 12 is a structural view of a first embodiment of a bed according to the present invention;

FIG. 13 is a cross sectional view of a middle part of the bed according to FIG. 12, showing connection of two ends of a transverse rod with corresponding beams;

FIG. 14 shows a connecting structure between the transverse rods of the bed according to the present invention;

FIG. 15 shows a connecting structure between a transverse rod and a corresponding beam of the bed according to the present invention;

FIG. 16 is an enlarged view of portion D shown in FIG. 12;

FIG. 17 is a structural view of a second embodiment of a bed according to the present invention.

Reference Numerals in the Figures

• • 100—bed;
  • 1—column; 11—insertion hole; 12—first screw hole; 13—rail;
  • 2—beam; 20—end of beam; 21—connecting plate; 211—third screw hole; 22—locking groove; 221—insertion section; 222—locking section;
  • 3—connector; 30—opening; 31—bottom wall; 311—second screw hole; 312—through opening; 32—side wall; 33—flange;
  • 4—screw;
  • A—headboard; B—footboard; C—side rod; 5—transverse rod; 51—fixture; 511—fixing hook portion; 512—middle stem; 52—locking part; 521—notch; 53—fixing block; 531—clamping section;
  • 6—transverse crossbar; 7—leg.

DETAILED DESCRIPTION OF THE INVENTION

In order to explain the technical solutions of the present invention in greater details, the present invention will be further described below in detail with reference to some embodiments.

As shown in FIGS. 1 to 5, a first embodiment of the beam and column connecting structure is shown, comprising a column 1, a beam 2, and a connector 3; the column 1 is provided with an insertion hole 11 having a shape corresponding to a sectional shape of the beam 2 at an area of the column 1 where the beam 2 is connected with the column 1; the connector 3 is inserted into the insertion hole 11; an end 20 of the beam 2 is inserted into the connector 3.

Said connector 3 comprises a bottom wall 31 and four side walls 32; a top side of the connector 3 is an opening 30; the beam 2 is inserted into the connector 3 through the opening 30; the bottom wall 31 of the connector 3 has a contour corresponding to a contour of an inner side wall of the column 1; the bottom wall 31 of the connector 3 completely abuts against an area of the inner side wall of the column 1 opposite to the insertion hole 11; accordingly, the bottom wall 31 of the connector 3 can be tightly in contact with the inner side wall of the column 1. After said end 20 of the beam 2 is inserted into the connector 3, said end 20 of the beam 2 completely abuts against an inner side wall of the connector 3; in other words, an insertion groove is defined by the bottom wall 31, the four side walls 32, and the opening 30 of the connector, into which the beam 2 is inserted; further, the insertion groove has a shape that corresponds to a shape of said end 20 of the beam 2, so that after said end 20 of the beam 2 is inserted into the connector 3, said end 20 of the beam 2 can tightly and completely abut against the inner side wall of the connector 3. Further, the top side of the connector 3 is provided with a flange 33 protruding outwardly around the opening 30; the flange 33 completely abuts against an outer side wall of the column 1 surrounding the insertion hole 11 so that the connector 3 is further fixed in position. Also, said end 20 of the beam 2 inserted into the connector 3 is provided with a connecting plate 21 recessed inside said end 20 of the beam 2 and connecting to inner side walls of the beam 2; at least one screw hole is provided through the column 1 at an area of the column 1 corresponding to the bottom wall 31 of the connector 3, and at least one screw hole is also provided through the connecting plate 21 of the beam 2; said at least one screw hole through the column 1 correspond to the said at least one screw hole through the connecting plate 21; also, the bottom wall 31 of the connector 3 are correspondingly provided with at least one screw hole or a through opening through which at least one screw can pass through. In the present embodiment, at least one first screw hole 12 is provided through the column 1 at the area of the column 1 corresponding to the bottom wall 31 of the connector 3; at least one second screw hole 311 is provided through the bottom wall 31 of the connector 3; at least one third screw hole 211 corresponding to said at least one first screw hole 12 is provided through the connecting plate 21; at least one screw 4 may be inserted from the outer side wall of the column 1 passing through said at least one first screw hole 12, said at least one second screw hole 311, and said at least one third screw hole 211 sequentially, so as to fix the column 1, the connector 3 and the beam 2 together; as such, said end 20 of the beam 2 is connected to the column 1 together with the connector 3.

In view of the above, the connector 3 according to the above embodiment is primarily installed inside the column 1, except for the flange 33 which is fitted on the outer side wall of the column 1 surrounding the insertion hole 11; further, said end 20 of the beam 2 is accommodated inside the column 1; mutually contacting surfaces between the column 1, the connector 3, and the beam 2 are tightly in complete contact with one another, so that the overall structure of the connecting structure is more compact; other external components like metal sheet which may otherwise affect the stability of connection are no longer required, and safety hazards due to loosened structure or noise due to friction, both resulted from external factors like shaking and wobbling, can be prevented.

Preferably, the connector 3 is made of plastic material to further prevent noise due to friction.

After said end 20 of the beam 2 is inserted into the connector 3, said end 20 of the beam 2 abuts an inner side of the bottom wall 31 of the connector 3, wherein said inner side of the bottom wall 31 of the connector 3 is a flat surface that allows complete contact with said end 20 of the beam 2; also, when the connector 3 is inserted into the insertion hole 11, the bottom wall 31 of the connector 3 tightly and completely abuts against the inner side wall of the column 1, and the flange 33 disposed around the opening 33 of the connector 3 tightly and completely abuts against the outer side wall of the column 1 surrounding the insertion hole 11, thereby dividing the load of connection to different force bearing points and hence increasing the support strength.

In this embodiment, the column 1 is a cylindrical tube; an outer side of the bottom wall 31 is an arc surface which is in complete contact with the inner side wall of the column 1 when the connector 3 is inserted into the insertion hole 11; the flange 33 around the opening 30 of the connector 3 has two widths bent to be shaped as arcs so that the flange 33 is in complete contact with the outer side wall of the column 1 when the connector 3 is inserted into the insertion hole 11; said inner side of the bottom wall 31 is a flat surface that is in complete contact with an end surface of said end 20 of the beam 2 when said end 20 of the beam 2 is inserted into the connector 3.

In the present invention, a particular shape of the connector 3, and more particularly, a shape of the outer side of the bottom wall 31 and a shape of the flange 33, can be designed in accordance with a shape of the column 1, so that mutually contacting surfaces between the column 1, the connector 3, and the beam 2 are capable to be in complete contact to ensure stable connection.

With reference to FIGS. 6 to 10, a second embodiment of the present invention is shown; this second embodiment is different from the first embodiment in the following aspects: the column 1 is a tube with a shape of a rectangular prism, and the connector 3 is also in a shape of a rectangular prism; the bottom wall 31 of the connector 3 is a flat wall that allows complete contact of the bottom wall 31 with the inner side wall of the column 1 and complete contact with said end surface of said end 20 of the beam 2. In the present embodiment, the inner side and the outer side of the bottom wall 31 of the connector 3 are both flat surfaces, wherein the inner side of the bottom wall 31 is in complete contact with said end surface of said end 20 of the beam 2, and the outer side of the bottom wall is in complete contact with said inner side wall of the column 1. In the present embodiment, a center part of each of the four side walls 32 of the connector 3 is cut out to form an opening to reduce a weight of the connector 3 and save materials.

With reference to FIG. 11, a third embodiment of the present invention is shown; the third embodiment is different from the second embodiment in the following aspects: Apart from the four side walls 32, a center part of the bottom wall 31 is also cut out to form a through opening 312 which said at least one screw 4 can pass through. During connection, said at least one screw 4 is inserted from the outer side wall of the column 1 through said at least first screw hole 12, the through opening 312, and said at least one third screw hole 211 sequentially, so that the column 1, the connector 3, and the beam 2 are fixed together.

With reference to FIG. 12, a bed 100 is disclosed, comprising a headboard A, a footboard B, and two side rods C spaced apart from each other in parallel each having two ends connected to the headboard A and the footboard B respectively; each of the headboard A and the footboard B comprises two columns 1 spaced apart from each other in parallel; each column 1 is supported against a ground; each of the two side rods C comprises at least one beam 2, specifically, each of the two side rods C may comprise only one beam (as shown later in FIG. 17), or two beams connected in series as in the current embodiment shown in FIG. 12, or more than two beams connected in series (not shown in the figures); in the current embodiment, in each of the two side rods C, two outer ends of two respective beams 2 corresponding to two ends of the corresponding side rod C respectively are connected to corresponding columns 1 of the headboard A and the footboard B respectively; said beam and column connecting structure is used for connection between each outer end of a respective beam 2 and a corresponding column 1. As shown in FIG. 17, each of the two side rods C may comprise only one beam 2, and in this case, in each of the two side rods C, two ends of the beam 2 are connected to corresponding columns 1 of the headboard A and the footboard B respectively.

The bed 100 illustrated by FIG. 12 uses said beam and column connecting structure according to the second embodiment described above. Specifically, each of the two side rods C comprises two beams 2 connected in series, such that each of the two side rods C can be divided into two at a middle part thereof to facilitate packaging and transportation. The bed 100 also comprises a transverse crossbar 6, a plurality of transverse rods 5, a plurality of rails 13, and at least one leg 7. Said plurality of rails 13 are disposed between two columns 1 of each of the headboard A and the footboard B. Said plurality of transverse rods 5 spaced apart evenly with one another are positioned perpendicularly with respect to the two side rods C parallel and opposite to each other, and two ends of each of said plurality of transverse rods 5 are connected to the two side rods C respectively; each of two ends of said transverse crossbar 6 is connected to a joint between said two beams 2 of a corresponding side rod C; said transverse crossbar 6 is positioned below said plurality of transverse rods 5. Said at least one leg 7 supports said transverse crossbar 6. In FIG. 10 as shown, said at least one leg 7 comprises two legs 7, and the two legs 7 support two end portions of said transverse crossbar 6 respectively.

With reference to FIG. 14, a plurality of fixtures 51 are provided to connect said plurality of transverse rods 5, wherein each of said plurality of fixtures 51 is used to connect every two adjacent transverse rods 5, so that the plurality of transverse rods 5 can be more stably spaced apart from one another. Each of the plurality of fixtures 51 comprises a middle stem 512 and two fixing hook portions 511 disposed on two ends of the middle stem 512 respectively; the two fixing hook portions 511 hook on two adjacent transverse rods 5 respectively. Specifically, the two fixing hook portions 511 hook on middle points of the two adjacent transverse rods 5 respectively.

With reference to FIG. 12 to FIG. 16, a connecting structure between each of the plurality of transverse rods 5 and corresponding beams 2 is shown, wherein each of the two ends of each of the plurality of transverse rods 5 is provided with a locking part 52; a corresponding inner lateral wall of each of the corresponding beams 2 is provided with a plurality of locking grooves 22 spaced apart evenly with one another along a lengthwise direction of the beam 2; the locking part 52 provided at each of the two ends of each of the plurality of transverse rods 5 is inserted into a corresponding locking groove 22 of a corresponding beam 2, and thus being located on the inner lateral wall of the corresponding beam 2; a fixing block 53 is provided at each of the plurality of locking grooves 22, and an upper end and a lower end of each fixing block 53 are clamped at an upper end and a lower end of a corresponding locking groove 22, accordingly, the fixing block 53 fixes a position of a corresponding locking part 52 inserted into the corresponding locking groove 22. Each of the plurality of locking grooves 22 comprises an insertion section 221 and a locking section 222; each locking part 52 comprises a notch 521 corresponding to the locking section 222; during installation, the locking part 52 is inserted into the insertion section 221 of a corresponding locking groove 22, and then the locking part 52 is slid laterally into the locking section 222 of the corresponding locking groove 22 through the notch 521, so that the notch 521 of the locking part 52 will have a portion of the inner lateral wall of a corresponding beam 2 fitted therein, and finally, the fixing block 53 is inserted into the insertion section 221 of the corresponding locking groove 22, wherein a clamping section 531 provided on each of the upper end and the lower end of the fixing block clamp onto the upper end and the lower end of the corresponding locking groove 22 so that the fixing blocking 53 is fixed on the insertion section 221 of the corresponding locking groove 22, thereby limiting the locking part 52 within the locking section 222 of the corresponding locking groove 22; accordingly, a stable connection is achieved between each of the plurality of transverse rods 5 and the corresponding beams 2.

Although embodiments of the present invention are illustrated and described above, they are not intended to limit the present invention. Any changes, modifications, or replacements intended to achieve the same technical results, made in accordance with the essence and principle of the present invention, shall also fall within the scope of protection of the present invention.

Claims

1. A beam and column connecting structure, comprising a column, a beam, and a connector; the column is provided with an insertion hole having a shape corresponding to a sectional shape of the beam at an area of the column where the beam is connected with the column; the connector is inserted into the insertion hole; an end of the beam is inserted into the connector;said connector comprises a bottom wall and four side walls; a top side of the connector is an opening; said end of the beam is inserted into the connector through the opening; an outer side of the bottom wall of the connector has a contour corresponding to a contour of an inner side wall of the column; the outer side of the bottom wall of the connector completely abuts against an inner side wall of the column; an end surface of said end of the beam completely abuts against an inner side wall of the connector; the top side of the connector is provided with a flange protruding outwardly around the opening; the flange completely abuts against an outer side wall of the column surrounding the insertion hole;said end of the beam inserted into the connector is provided with a connecting plate recessed inside said end of the beam and connecting to inner side walls of the beam; at least one first screw hole is provided through the column at an area of the column corresponding to the bottom wall of the connector, and at least one third screw hole is also provided through the connecting plate of the beam; said at least one first screw hole through the column corresponds to the said at least one third screw hole through the connecting plate; also, the bottom wall of the connector are correspondingly provided with at least one second screw hole or a through opening through which at least one screw passes through; said at least one screw is inserted from the outer side wall of the column passing through said at least one first screw hole, said at least one second screw hole or said through opening, and said at least one third screw hole sequentially, so as to fix the column, the connector and the beam together.

2. The beam and column connecting structure of claim 1, wherein the connector is made of plastic material.

3. The beam and column connecting structure of claim 1, wherein the end surface of said end of the beam abuts an inner side of the bottom wall of the connector, wherein said inner side of the bottom wall of the connector is a flat surface that allows complete contact with the end surface of said end of the beam.

4. The beam and column connecting structure of claim 2, wherein the column is a cylindrical tube; the outer side of the bottom wall is an arc surface which is in complete contact with the inner side wall of the column; the flange around the opening of the connector has two widths bent to be shaped as arcs so that the flange is in complete contact with the outer side wall of the column.

5. The beam and column connecting structure of claim 2, wherein the column is a tube with a shape of a rectangular prism, and the connector is also in a shape of a rectangular prism; the bottom wall of the connector is a flat wall that allows complete contact of the bottom wall with the inner side wall of the column and complete contact with said end surface of said end of the beam.

6. The beam and column connecting structure of claim 2, wherein a center part of each of the bottom wall and the four side walls of the connector is cut out to form an opening; the center part of the bottom wall being cut out form said through opening which said at least one screw passes through.

7. A bed, comprising a headboard, a footboard, and two side rods spaced apart from each other in parallel each having two ends connected to the headboard and the footboard respectively; each of the headboard and the footboard comprises two columns spaced apart from each other in parallel; each column is configured to be supported against a ground; each of the two side rods comprises at least one beam; wherein in each of the two side rods, two ends of the beam in case only one beam is provided, or two outer ends of two respective beams corresponding to two ends of the corresponding side rod respectively, in case more than one beam are provided, are connected to corresponding columns of the headboard and the footboard respectively; said beam and column connecting structure according to claim 1 is used for connection between each outer end of a respective beam and a corresponding column.

8. The bed of claim 7, wherein each of the two side rods comprises two beams connected in series; the bed also comprises a transverse crossbar, a plurality of transverse rods, a plurality of rails, and at least one leg; said plurality of rails are disposed between two columns of each of the headboard and the footboard; said plurality of transverse rods spaced apart evenly with one another are positioned perpendicularly with respect to the two side rods parallel and opposite to each other, and two ends of each of said plurality of transverse rods are connected to the two side rods respectively; each of two ends of said transverse crossbar is connected to a joint between said two beams of a corresponding side rod; said transverse crossbar is positioned below said plurality of transverse rods; said at least one leg supports said transverse crossbar.

9. The bed of claim 8, wherein a plurality of fixtures are provided to connect said plurality of transverse rods, wherein each of said plurality of fixtures is used to connect every two adjacent transverse rods; each of the plurality of fixtures comprises a middle stem and two fixing hook portions disposed on two ends of the middle stem respectively; the two fixing hook portions hook on two adjacent transverse rods respectively.

10. The bed of claim 8, wherein each of the two ends of each of the plurality of transverse rods is provided with a locking part; an inner lateral wall of each corresponding beam corresponding to said one of said two ends of each of the plurality of transverse rods is provided with a plurality of locking grooves spaced apart evenly with one another along a lengthwise direction of the beam; the locking part provided at each of the two ends of each of the plurality of transverse rods is inserted into a corresponding locking groove of a corresponding beam, and thus being located on the inner lateral wall of the corresponding beam; a fixing block is provided at each of the plurality of locking grooves, and an upper end and a lower end of each fixing block are clamped at an upper end and a lower end of a corresponding locking groove; the fixing block fixes a position of a corresponding locking part inserted into the corresponding locking groove.