Patent Publication Number: US-2020276509-A1

Title: Building blocks and connecting structures thereof

Description:
CROSS REFERENCE TO THE RELATED APPLICATIONS 
     This application is a Continuation-in-part application of U.S. application Ser. No. 16/069,177, filed on Jul. 11, 2018, which is the national stage of International Application No. PCT/CN2016/087403, filed on Jun. 28, 2016, which is based upon and claims priority to Chinese Patent Application No. 201620144240.3, filed on Feb. 26, 2016, the entire contents of which are incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The invention relates to the technical field of toys, and in particular to building blocks and connecting structures thereof. 
     BACKGROUND OF THE INVENTION 
     Building block toys have a great effect on children&#39;s intellectual development. Playing with building block toys is conducive to cultivation of children&#39;s practical ability and spatial imagination ability. When children play building block toys, it is important for the children to participate in solving issues of proportions, symmetry, and the like, which is of great significance to the early cultivation of children&#39;s arithmetic. 
     When building blocks are connected, generally, one of the building blocks is provided with one or more projecting portions for connecting, and another building block is provided with one or more recessed portions for connecting. In the existing building block toys, only recessed portions with one size are provided in a single building block, the single building block can only be connected with the same type of building blocks and cannot be connected with other different types of building blocks. Since different types of building blocks cannot be connected, the building block toys have reduced interestingness and children&#39;s creativity is restricted. 
     SUMMARY OF THE INVENTION 
     In order to solve the aforementioned problems, in a first respect, an objective of the present invention is to provide a building block which can be connected with other types of building blocks through second recessed portions, which enriches connection forms among the building blocks; in a second aspect, an objective of the present invention is to provide a connecting structure of building blocks in which one building block are connected with other types of building blocks through second recessed portions, which enriches connection forms among the building blocks; and in a third aspect, an objective of the present invention is to provide a connecting structure of building blocks in which connection between a first building block and a second building block is realized, which enriches connection forms between the first building blocks and the second building blocks and improves interestingness of building block toys. 
     In the first aspect, in order to achieve the aforementioned objective, a building block is provided according to the present invention, which comprises a building block body which is in a cubic structure and is composed of one first connecting surface and five second connecting surfaces, 
     wherein the first connecting surface is provided with two projecting portions and two first recessed portions each adapted to a projecting portion provided on a first connecting surface of another such building block; the two projecting portions are disposed on the first connecting surface along a first diagonal line, the two first recessed portions are disposed in the first connecting surface along a second diagonal line, and the first diagonal line and the second diagonal line intersect perpendicularly; and each of the second connecting surfaces is provided with the first recessed portions each adapted to a projecting portion provided on a first connecting surface of another such building block and at least one second recessed portion different from the first recessed portion in shape or size. 
     In a preferred embodiment, the second recessed portion has the size smaller than the first recessed portion. 
     In a preferred embodiment, a periphery of each of the first recessed portions is evenly provided with four second recessed portions that are in communication with the each of the first recessed portions. 
     In a preferred embodiment, a periphery of each of the projecting portions is evenly provided with four second recessed portions. 
     In a preferred embodiment, each of the second connecting surfaces is provided with four said first recessed portions, and every two said first recessed portions are disposed diagonally. 
     In a preferred embodiment, the second recessed portion has the size larger than the first recessed portion. 
     In a preferred embodiment, wherein the second recessed portion is provided in a center of each of the second connecting surfaces, and four said first recessed portions are in communication with said second recessed portion in the each of the second connecting surfaces. 
     In a preferred embodiment, one second recessed portion is provided in a center of the first connecting surface, and two said first recessed portions are both in communication with the one second recessed portion in the first connecting surface. 
     In a preferred embodiment, the projecting portions are in a hollow square columnar structure or in a columnar structure formed by a plurality of sheet-like structures arranged at intervals. 
     In a preferred embodiment, wherein the first recessed portions and the second recessed portions are in a blind hole structure or in a through hole structure. 
     In a preferred embodiment, centers of the first connecting surface and the second connecting surfaces are respectively provided with a through hole. 
     In the second aspect, in order to achieve the aforementioned objective, a connecting structure of building blocks is provided according to the present invention, which comprises a plurality of the aforementioned building blocks, in which the projecting portions of one said building block are inserted into the first recessed portions of another said building block such that the plurality of building blocks are connected together. 
     In the second aspect, in order to achieve the aforementioned objective, a connecting structure of building blocks is provided according to the present invention, which comprises at least one first building block and at least one second building block, wherein projecting portions of the first building block are inserted into first recessed portions of the second building block; the first building block comprises a first building block body, and the second building block comprises a second building block body; and the first building block body and the second building block body are both in a cubic structure; 
     the first building block body is composed of one third connecting surface and five fourth connecting surfaces, the third connecting surface is provided with first projecting portions and third recessed portions each adapted to a first projecting portion provided on a third connecting surface of another first building block body, and each of the fourth connecting surfaces is provided with the third recessed portions each adapted to a first projecting portion provided on a third connecting surface of another first building block body and fourth recessed portions having a size smaller than the third recessed portions; and 
     the second building block body is composed of one fifth connecting surface and five sixth connecting surfaces, the fifth connecting surface is provided with second projecting portions and fourth recessed portions each adapted to a second projecting portion provided on a fifth connecting surface of another second building block body, and each of the sixth connecting surfaces is provided with said fourth recessed portions each adapted to a second projecting portion provided on a fifth connecting surface of another second building block body and a third recessed portion adapted to a first projecting portion provided in a third connecting surface of the first building block body. 
     In a preferred embodiment, the third connecting surface is provided with two first projecting portions and two third recessed portions; the two first projecting portions are disposed on the third connecting surface along a third diagonal line, the two third recessed portions are disposed in the third connecting surface along a fourth diagonal line, and the third diagonal line and the fourth diagonal line intersect perpendicularly; and each of the fourth connecting surfaces is provided with four said third recessed portions, and every two said third recessed portions are disposed diagonally; and 
     the fifth connecting surface is provided with two second projecting portions and two fourth recessed portions, the two second projecting portions are disposed on the fifth connecting surface along a fifth diagonal line, the two fourth recessed portions are disposed in the fifth connecting surface along a sixth diagonal line, and the fifth diagonal line and the sixth diagonal line intersect perpendicularly; and each of the sixth connecting surfaces is provided with four said fourth recessed portions, and every two said fourth recessed portions are disposed diagonally. 
     In a preferred embodiment, the first building block body has a size larger than the second building block body. 
     In a preferred embodiment, an edge length of the first building block body is twice an edge length of the second building block body. 
     In a preferred embodiment, a periphery of each of the third recessed portions in the third connecting surface and the fourth connecting surfaces are evenly provided with four fourth recessed portions that are in communication with the each of the third recessed portions in the third connecting surface and the fourth connecting surfaces, and a periphery of each of the first projecting portions is evenly provided with four fourth recessed portions; 
     the third recessed portion of each of the sixth connecting surfaces is disposed in a center of the each of the sixth connecting surfaces, which is in communication with four said fourth recessed portions in the each of the sixth connecting surfaces; a center of the fifth connecting surface is provided with one third recessed portion, which is in communication with two fourth recessed portions in the fifth connecting surface. 
     In a preferred embodiment, the first projecting portions are in a hollow square columnar structure or in a columnar structure formed by a plurality of sheet-like structures arranged at intervals; and the second projecting portions are in a hollow square columnar structure or in a columnar structure formed by a plurality of sheet-like structures arranged at intervals. 
     Compared with the prior art, a building block and a connecting structure of building blocks according to embodiments of the present invention have the following beneficial effects: 
     Firstly, the building block body according to an embodiment of the present invention is provided with two types of recessed portions, the same type of building blocks can be connected through the first recessed portions in the first connecting surface or the second connecting surfaces, and the different types of building blocks can be connected through the second recessed portions, which can enrich the connection forms among building blocks and improve interestingness; 
     Secondly, in an embodiment of the present invention, one building block can be connected with another such building block by inserting the projecting portions of the one building block into the first recessed portions in the first connecting surface or the second connecting surfaces of the another such building block, and can be connected with another type of building blocks by inserting the projecting portions of the another type of building blocks into the second recessed portions of the one building block, which can enrich the connection forms among building blocks and improve interestingness; and 
     Thirdly, in an embodiment of the present invention, the first projecting portions on the first building block body can be inserted into the third recessed portions in the adjacent first building block body or into the third recessed portions in the adjacent second building block body, and the second projecting portions on the second building block body can be inserted into the fourth recessed portions of the adjacent second building block body or into the fourth recessed portions of the adjacent first building block body. The first projecting portions of the first building block body can be inserted into the third recessed portions of the second building block body, and the second projecting portions of the second building block body can be inserted into the fourth recessed portions of the first building block body, which results in a variety of connection possibilities, enriches the connection forms among the building blocks, and improves interestingness. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In order to more clearly explain the technical solutions of the embodiments of the present invention, the drawings of the embodiments will be briefly described below. 
         FIG. 1  is a schematic structural diagram of a building block according to Embodiment 1 of the present invention; 
         FIG. 2  is a schematic structural diagram of a building block according to Embodiment 2 of the present invention; 
         FIG. 3  is a schematic structural diagram of a building block according to Embodiment 3 of the present invention; 
         FIG. 4  is a schematic structural diagram of a building block according to Embodiment 4 of the present invention; 
         FIG. 5  is a schematic diagram of Connection form 1 of a connecting structure of building blocks according to Embodiment 5 of the present invention; 
         FIG. 6  is a schematic diagram of Connection form 2 of a connecting structure of building blocks according to Embodiment 5 of the present invention; 
         FIG. 7  is a schematic diagram of Connection form 3 of a connecting structure of building blocks according to Embodiment 5 of the present invention; 
         FIG. 8  is a schematic diagram of a connecting structure of building blocks according to Embodiment 6 of the present invention; 
         FIG. 9  is a schematic diagram of a connecting structure of building blocks according to Embodiment 7 of the present invention; 
         FIG. 10  is a schematic diagram of a connecting structure of building blocks according to Embodiment 8 of the present invention; 
         FIG. 11  is a schematic diagram of a connecting structure of building blocks according to Embodiment 9 of the present invention; and 
         FIG. 12  is a schematic diagram of a connecting structure of building blocks according to Embodiment 10 of the present invention. 
     
    
    
     In the drawings,  11   a:  first connecting surface;  12   a:  second connecting surface;  13   a:  projecting portion;  14   a:  first recessed portion;  15   a:  second recessed portion; A: first diagonal line; B: second diagonal line; 
       11   b:  first connecting surface;  12   b:  second connecting surface;  13   b:  projecting portion;  14   b:  first recessed portion;  15   b:  second recessed portion;  16 : through hole; A′: first diagonal line; B′: second diagonal line; 
       11   c:  third connecting surface;  12   c:  fourth connecting surface;  13   c:  first projecting portion;  14   c:  third recessed portion;  15   c:  fourth recessed portion; C: third diagonal line; D: fourth diagonal line;  11   d:  fifth connecting surface;  12   d:  sixth connecting surface;  13   d:  second projecting portion;  14   d:  third recessed portion;  15   d:  fourth recessed portion; C′: fifth diagonal line; D′: sixth diagonal line; and 
       11   e:  third connecting surface;  12   e:  fourth connecting surface;  13   e:  first projecting portion;  14   e:  third recessed portion;  15   e:  fourth recessed portion;  11   f:  fifth connecting surface;  12   f:  sixth connecting surface;  13   f:  second projecting portion;  15   f:  fourth recessed portion. 
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. The following embodiments are used to illustrate the present invention, but not to limit the scope of the present invention. 
     It should be understood that the terms “first”, “second”, and the like are used in the present invention to describe various kinds of information, but the information should not be limited to these terms, these terms are only used to distinguish the same type of information from each other. For example, without departing from the scope of the invention, “first” information may also be referred to as “second” information, and similarly, the “second” information may also be referred to as the “first” information. 
     It should be noted that a building block body in a cubic structure means that when the building block body is not provided with projecting portions and recessed portions, the whole thereof is in a cubic structure. 
     Embodiment 1 
     Refer to  FIG. 1 , a building block according to the embodiment of the present invention comprises a building block body which is in a cubic structure and is composed of one first connecting surface  11   a  and five second connecting surfaces  12   a.  The first connecting surface  11   a  is provided with projecting portions  13   a  and first recessed portions  14   a  each adapted to a projecting portion  13   a  provided on a first connecting surface  11   a  of another such building block. Each of the second connecting surfaces  12   a  is provided with the first recessed portions  14   a  each adapted to a projecting portion  13   a  provided on a first connecting surface  11   a  of another such building block and second recessed portions  15   a  different from the first recessed portions  14   a  in shape or size. 
     Preferably, the first connecting surface  11   a  is provided with two projecting portions  13   a  and two first recessed portions  14   a.  The two projecting portions  13   a  are disposed on the first connecting surface  11   a  along a first diagonal line A, the two first recessed portions  14   a  are disposed in the first connecting surface  11   a  along a second diagonal line B, and the first diagonal line A and the second diagonal line B intersect perpendicularly. Each of the second connecting surfaces  12   a  is provided with four first recessed portions  14   a,  and every two said first recessed portions  14   a  are disposed diagonally, which can make the connection between two adjacent building block bodies more stable and not easy to be loose. 
     In particular, the second recessed portion  15   a  has the size smaller than the first recessed portion  14   a.  A periphery of each of the first recessed portions  14   a  is evenly provided with four second recessed portions  15   a  that are in communication with the each of the first recessed portions  14   a.  That the four first recessed portions  14   a  are in communication with the each of the second recessed portions  15   a  can increase deformation amounts of the first recessed portions  14   a  and the second recessed portions  15   a,  so that the projecting portions of a building block can be more easily inserted into the recessed portions  14   a  or the second recessed portions  15   a  of an adjacent such building block. The second recessed portions  15   a  in the first connecting surface  11   a  and the second connecting surfaces  12   a  can be inserted with projecting portions of another type of building blocks. 
     Preferably, the projecting portions  13   a  are in a hollow square columnar structure or in a columnar structure formed by a plurality of sheet-like structures arranged at intervals. In this embodiment, the projecting portions  13   a  are preferably in a columnar structure formed by a plurality of sheet-like structures arranged at intervals. In this way, the projecting portions  13   a  are easier to deform and the connection is more labor-saving. 
     Preferably, the first recessed portions  14   a  and the second recessed portions  15   a  are in a blind hole structure or in a through hole structure. In this embodiment, the first recessed portions  14   a  and the second recessed portions  15   a  are in a through hole structure. 
     Thus, the building block in Embodiment 1 of the present invention is provided with two types of recessed portions with different size, the building block can be connected with another such building block through the first recessed portions  14   a  in the first connecting surface  11   a  or the second connecting surfaces  12   a,  and can also be connected with other type of building blocks through the second recessed portions  15   a,  which enriches the connection forms among the building blocks and improves interestingness. 
     Embodiment 2 
     Refer to  FIG. 2 . This embodiment differs from Embodiment 1 in that a periphery of each of the projecting portions  13   a  is evenly provided with four second recessed portions  15   a.    
     The other arrangement in this embodiment is the same as that of Embodiment 1, and will not be repeated here. 
     Embodiment 3 
     Refer to  FIG. 3 . This embodiment differs from Embodiment 1 in that centers of the first connecting surface  11   a  and the second connecting surfaces  12   a  are each provided with a through hole  16 . 
     The other arrangement in this embodiment is the same as that of Embodiment 1, and will not be repeated here. 
     Embodiment 4 
     Refer to  FIG. 4 , a building block according to the embodiment of the present invention comprises a building block body which is in a cubic structure and is composed of one first connecting surface  11   b  and five second connecting surfaces  12   b.  The first connecting surface  11   b  is provided with projecting portions  13   b  and first recessed portions  14   b  each adapted to a projecting portion  13   b  provided on a first connecting surface  11   b  of another such building block. Each of the second connecting surfaces  12   b  is provided with the first recessed portions  14   b  each adapted to a projecting portion  13   b  provided on a first connecting surface  11   b  of another such building block and one second recessed portion  15   b  different from the first recessed portion  14   b  in shape or size. 
     Preferably, the first connecting surface  11   b  is provided with two projecting portions  13   b  and two first recessed portions  14   b.  The two projecting portions  13   b  are disposed on the first connecting surface  11   b  along a first diagonal line A′, the two first recessed portions  14   b  are disposed in the first connecting surface  11   b  along a second diagonal line B′, and the first diagonal line A′ and the second diagonal line B′ intersect perpendicularly. Each of the second connecting surfaces  12   b  is provided with four first recessed portions  14   b,  and every two said first recessed portions  14   b  are disposed diagonally, which can make the connection between two adjacent building block bodies more stable and not easy to be loose. 
     In particular, the second recessed portion  15   b  has the size smaller than the first recessed portion  14   b.  The second recessed portion  15   b  is provided in a center of each of the second connecting surfaces  12   b,  and four said first recessed portions  14   b  are in communication with the recessed portion  15   b  in the each of the second connecting surfaces  12   b.  One second recessed portion  15   b  is provided in a center of the first connecting surface  11   b,  and two first recessed portions  14   b  are both in communication with the second recessed portion  15   b  in the first connecting surface  11   b.  The first recessed portions  14   b  are in communication with the second recessed portion  15   b  in each of connecting surfaces, which can increase deformation amounts of the first recessed portions  14   b  and the second recessed portions  15   b,  so that the projecting portions of a building block can be more easily inserted into the recessed portions  14   b  or the second recessed portions  15   b  of an adjacent building block. The second recessed portions  15   b  in the first connecting surface  11   b  and the second connecting surfaces  12   b  can be inserted with projecting portions of another type of building blocks. 
     Preferably, the projecting portions  13   b  are in a hollow square columnar structure or in a columnar structure formed by a plurality of sheet-like structures arranged at intervals. In this embodiment, the projecting portions  13   b  are preferably in a hollow square columnar structure. In this way, the hollow structure of the projecting portions  13   b  provides a deformation space for the deformation of the projecting portions  13  and makes connection more labor-saving. 
     Preferably, the first recessed portions  14   b  and the second recessed portions  15   b  are in a blind hole structure or in a through hole structure. In this embodiment, the first recessed portions  14   b  and the second recessed portions  15   b  are preferably in a through hole structure. 
     Thus, the building block in Embodiment 4 of the present invention is provided with two types of recessed portions with different size, the building block can be connected with another such a building block through the first recessed portions  14   b  in the first connecting surface  11   b  or the second connecting surfaces  12   b,  and can also be connected with other type of building blocks through the second recessed portions  15   a,  which enriches the connection forms among the building blocks and improves interestingness. 
     Embodiment 5 
     Refer to  FIGS. 5 to 7 . A connecting structure of building blocks according this embodiment of the present invention comprises a plurality of building blocks that are the same as that in Embodiment 1, in which projecting portions  13   a  of one said building block are inserted into first recessed portions  14   a  of another said building block such that the plurality of building blocks are connected together. A user can connect a plurality of building blocks into building block toys of different shapes according to needs. When any two building blocks are connected, two projecting portions  13   a  on the first connecting surface  11   a  of a first building block can be respectively inserted into two first recessed portions  14   a  in any of the second connecting surfaces  12   a  of a second building block. Alternatively, the two projecting portions  13   a  on the first connecting surface  11   a  of the first building block can be respectively inserted into the two first recessed portions  14   a  in the first connecting surface  11   a  of the second building block, so that the two projecting portions  13   a  on the first connecting surface  11   a  of the second building block can be respectively simultaneously inserted into the two first recessed portions  14   a  in the first connecting surface  11   a  of the first building block. A building block toy connected in this way has no projecting portion  13   a  on its surfaces, so that aesthetics of the building block toy is improved. 
     Thus, in the connecting structure of building blocks according to Embodiment 5 of the present invention, two adjacent building blocks are connected by inserting projecting portions of one building block into first recessed portions  14   a  in the first connecting surface  11   a  or any of the second connecting surfaces  12   a,  and the second recessed portions  15   a  can be used for being inserted with projecting portions of another type of building blocks, which enriches the connection forms and improves interestingness. 
     Embodiment 6 
     Refer to  FIG. 8 . This embodiment differs from Embodiment 5 in that, a periphery of each projecting portion  13   a  is evenly provided four second recessed portions  15   a,  so that the projection portions of another type of building block can be inserted into the second recessed portions  15   a,  which enables another type of building block to connect with the building block according to this embodiment and further improves interestingness. 
     The other arrangement in this embodiment is the same as that of Embodiment 5, and will not be repeated here. 
     Embodiment 7 
     Refer to  FIG. 9 . A connecting structure of building blocks according this embodiment of the present invention comprises a plurality of building blocks that are the same as that in Embodiment 4, in which projecting portions  13   b  of one said building block are inserted into first recessed portions  14   b  of another said building block such that the plurality of building blocks are connected together. A user can connect a plurality of building blocks into building block toys of different shapes according to needs. When any two building blocks are connected, two projecting portions  13   b  on the first connecting surface  11   b  of a first building block can be respectively inserted into two first recessed portions  14   b  in any of the second connecting surfaces  12   a  of a second building block. Alternatively, the two projecting portions  13   b  on the first connecting surface  11   b  of the first building block can be respectively inserted into the two first recessed portions  14   b  in the first connecting surface  11   b  of the second building block, so that the two projecting portions  13   b  on the first connecting surface  11   b  of the second building block can be respectively simultaneously inserted into the two first recessed portions  14   b  in the first connecting surface  11   b  of the first building block. A building block toy connected in this way has no projecting portion  13   b  on its surfaces, so that aesthetics of the building block toy is improved. 
     Thus, in the connecting structure of building blocks according to Embodiment 7 of the present invention, two adjacent building blocks are connected by inserting the projecting portions of one building block into the first recessed portions  14   b  in the first connecting surface  11   b  or any of the second connecting surfaces  12   b,  and the second recessed portions  15   b  can be used for being inserted with projecting portions of another type of building blocks, which enriches the connection forms and improves interestingness. 
     Embodiment 8 
     Refer to  FIG. 10 . A connecting structure of building blocks according to this embodiment of the present invention comprises at least one first building block and at least one second building block, in which projecting portions of the first building block are inserted into first recessed portions of the second building block. The first building block comprises a first building block body, and the second building block comprises a second building block body. The first building block body and the second building block body are both in a cubic structure. 
     The first building block body is composed of one third connecting surface  11   c  and five fourth connecting surfaces  12   c.  The third connecting surface  11   c  is provided with first projecting portions  13   c  and third recessed portions  14   c  each adapted to a first projecting portion  13   c  provided on a third connecting surface  11   c  of another first building block body. Each of the fourth connecting surfaces  12   c  is provided with the third recessed portions  14   c  each adapted to a first projecting portion  13   c  provided on a third connecting surface  11   c  of another first building block body and fourth recessed portions  15   c  having a size smaller than the third recessed portions  14   c.    
     The second building block body is composed of one fifth connecting surface  11   d  and five sixth connecting surfaces  12   d.  The fifth connecting surface  11   d  is provided with second projecting portions  13   d  and fourth recessed portions  15   d  each adapted to a second projecting portion  13   d  provided on a fifth connecting surface  11   d  of another second building block body. Each of the sixth connecting surfaces  12   d  is provided with the fourth recessed portions  15   d  each adapted to a second projecting portion  13   d  provided on a fifth connecting surface  11   d  of another second building block body and a third recessed portion  14   d  adapted to a first projecting portion  13   c  provided in a first connecting surface  11   c  of another first building block body. 
     Preferably, the third connecting surface  11   c  is provided with two first projecting portions  13   c  and two third recessed portions  14   c.  The two first projecting portions  13   c  are disposed on the third connecting surface  11   c  along a third diagonal line C, the two third recessed portions  14   c  are disposed in the third connecting surface  11   c  along a fourth diagonal line D, and the third diagonal line C and the fourth diagonal line D intersect perpendicularly. Each of the fourth connecting surfaces  12   c  is provided with four third recessed portions  14   c,  and every two said third recessed portions  14   c  are disposed diagonally. 
     The fifth connecting surface  11   d  is provided with two second projecting portions  13   d  and two fourth recessed portions  15   d.  The two second projecting portions  13   d  are disposed on the fifth connecting surface  11   d  along a fifth diagonal line C′, the two fourth recessed portions  15   d  are disposed in the fifth connecting surface  11   d  along a sixth diagonal line D′, and the fifth diagonal line C′ and the sixth diagonal line D′ intersect perpendicularly. Each of the sixth connecting surfaces  12   d  is provided with four fourth recessed portions  15   d,  and every two said fourth recessed portions  15   d  are disposed diagonally. In this way, the connection between two adjacent building blocks is more stable and is not easy to loose. 
     Preferably, the first building block body has a size larger than the second building block body. Preferably, an edge length of the first building block body is twice an edge length of the second building block body. A periphery of each of the third recessed portions  14   c  in the third connecting surface  11   c  and the fourth connecting surfaces  12   c  are evenly provided with four fourth recessed portions  15   c  that are in communication with the each of the third recessed portions  14   c  in the third connecting surface  11   c  and the fourth connecting surfaces  12   c,  which can increase the deformation amounts of the third recessed portions  14   c  and the fourth recessed portions  15   c,  so that it is easier for the projecting portions to be inserted into the third recessed portions  14   c  and the fourth recessed portions  15   c.    
     The third recessed portion  14   d  of each of the sixth connecting surfaces  12   d  is disposed in a center of the each of the sixth connecting surfaces  12   d,  which is in communication with four said fourth recessed portions  15   d  in the each of the sixth connecting surfaces  12   d.  A center of the fifth connecting surface  11   d  is provided with one third recessed portion  14   d  which is in communication with two fourth recessed portions  15   d  in the fifth connecting surface  11   d.  In this way, the deformation amounts of the third recessed portions  14   d  and the fourth recessed portions  15   d  can be increased, so that it is easier for the projecting portions to be inserted into the third recessed portions  14   d  and the fourth recessed portions  15   d.    
     When any two first building blocks are connected, two first projecting portions  13   c  on the third connecting surface  11   c  of a first first building block bodies can be respectively inserted into two third recessed portions  14   c  in any one of the fourth connecting surfaces  12   c  of a second first building block bodies. Alternatively, the two first projecting portions  13   c  on the third connecting surface  11   c  of the first first building block bodies can be respectively inserted into the two third recessed portions  14   c  in the third connecting surface  11   c  of the second first building block bodies, so that the two first projecting portions  13   c  on the third connecting surface  11   c  of the second first building block bodies can be respectively simultaneously inserted into the two third recessed portions  14   c  in the third connecting surface  11   c  of the first first building block bodies. A building block toy connected in this way has no first projecting portion  13   c  on its surfaces. 
     When any two second building blocks are connected, two second projecting portions  13   d  on the fifth connecting surface  11   d  of a first second building block bodies can be inserted respectively into two fourth recessed portions  15   d  in any one of the sixth connecting surfaces  12   d  of a second second building block bodies. Alternatively, the two second projecting portions  13   d  on the fifth connecting surface  11   d  of the first second building block bodies can be respectively inserted into the two fourth recessed portions  15   d  in the fifth connecting surface  11   d  of the second second building block bodies, so that the two second projecting portions  13   c  on the fifth connecting surface  11   d  of the second second building block bodies can be respectively simultaneously inserted into the two fourth recessed portions  15   d  in the fifth connecting surface  11   d  of the first second building block bodies. A building block toy connected in this way has no second projecting portion  13   d  on its surfaces. 
     When a first building block and a second building block are connected, two second projecting portions  13   d  on the fifth connecting surface  11   d  of the second building block body can be respectively inserted into two fourth recessed portions  15   c  in any one of the fourth connecting surfaces  12   c  of the first building block body. Alternatively, two second projecting portions  13   d  on the fifth connecting surface  11   d  of the second building block body can be respectively inserted into two fourth recessed portions  15   c  in any one of the third connecting surfaces  12   c  of the first building block body. Alternatively, the first projecting portions  13   c  on the third connecting surface  11   c  of the first building block body can be respectively inserted into the third recessed portions  14   d  in the fifth connecting surface  11   d  or in any one of the fourth connecting surfaces  12   d.    
     Furthermore, the first projecting portions  13   c  are in a hollow square columnar structure or in a columnar structure formed by a plurality of sheet-like structures arranged at intervals; and the second projecting portions  13   d  are in a hollow square columnar structure or in a columnar structure formed by a plurality of sheet-like structures arranged at intervals. In this embodiment, the first projecting portions  13   c  are in a columnar structure formed by a plurality of sheet-like structures arranged at intervals, and the second projecting portions  13   d  are in a hollow square columnar structure, so that the first projecting portions  13   c  and the second projecting portions  13   d  are more easily deformed and the connection of building blocks is more labor-saving. 
     Thus, in the connecting structure of building blocks according to Embodiment 8 of the present invention, the first projecting portions  13   c  of the first building block body can be inserted into the third recessed portions  14   c  of one adjacent first building block body or into the third recessed portions  14   d  of one adjacent second building block; and the second projecting portions  13   d  of the second building block body can be inserted into the fourth recessed portions  15   d  of one adjacent second building block body or into the fourth recessed portions  15   c  of one adjacent first building block body. The first building block body and the second building block body can be connected to each other, so that there can be a variety of connecting possibilities, which enriches the connection forms among different types of building blocks and improves interestingness. 
     Embodiment 9 
     Refer to  FIG. 11 . This embodiment differs from Embodiment 8 in that a periphery of each first projecting portion  13   c  is evenly provided four fourth recessed portions  15   c.  When a first building block and a second building block are connected, on the one hand, the two projecting portions  13   d  on the fifth connecting surface  11   d  of the second building block body can be respectively inserted into the two fourth recessed portions  15   c  disposed at a periphery of the first projecting portion  13   c  of the first building block body; on the other hand, one first projecting portion  13   c  on the third connecting surface  11   c  of the first building block body can be inserted into one third recessed portion  14   c  in the fifth connecting surface  11   d  of the second building block body. A building block toy connected in this way has no redundant first projecting portions  13   c  and second projecting portions  13   d  on its surfaces, so that aesthetics of the building block toy is improved. 
     The other arrangement in this embodiment is the same as that of Embodiment 8, and will not be repeated here. 
     Embodiment 10 
     Refer to  FIG. 12 . A connecting structure of building blocks according to this embodiment of the present invention comprises at least one first building block and at least one second building block, in which projecting portions of the first building block are inserted into recessed portions of the second building block. The first building block comprises a first building block body, and the second building block comprises a second building block body. The first building block body and the second building block body are both in a cubic structure. 
     The first building block body is composed of one third connecting surface  11   e  and five fourth connecting surfaces  12   e.  The third connecting surface  11   e  is provided with first projecting portions  13   e  and third recessed portions  14   e  each adapted to a first projecting portion  13   e  provided on a third connecting surface  11   e  of another first building block body. Each of the fourth connecting surfaces  12   e  is provided with the third recessed portions  14   e  each adapted to a first projecting portion  13   e  provided on a third connecting surface  11   e  of another first building block body and fourth recessed portions  15   e  having a size smaller than the third recessed portions  14   e.    
     The second building block body is composed of one fifth connecting surface  11   f  and five sixth connecting surfaces  12   f  The fifth connecting surface  11   f  is provided with second projecting portions  13   f  and fourth recessed portions  15   f  each adapted to a second projecting portion  13   f  provided on the fifth connecting surface  11   f  of another second building block body. Each of the sixth connecting surfaces  12   f  is provided with the fourth recessed portions  15   f  each adapted to a second projecting portion  13   f  provided on the fifth connecting surface  11   f  of another second building block body. 
     Preferably, the third connecting surface  11   c  is provided with two first projecting portions  13   e  and two third recessed portions  14   e.  The two first projecting portions  13   e  are disposed on the third connecting surface  11   e  along a third diagonal line C, the two third recessed portions  14   e  are disposed in the third connecting surface  11   e  along a fourth diagonal line D, and the third diagonal line C and the fourth diagonal line D intersect perpendicularly. Each of the fourth connecting surfaces  12   e  is provided with four third recessed portions  14   e,  and every two said third recessed portions  14   e  are disposed diagonally. 
     The fifth connecting surface  11   f  is provided with two second projecting portions  13   f  and two fourth recessed portions  15   f  The two second projecting portions  13   f  are disposed on the fifth connecting surface  11   f  along a fifth diagonal line C′, the two fourth recessed portions  15   f  are disposed in the fifth connecting surface  11   f  along a sixth diagonal line D′, and the fifth diagonal line C′ and the sixth diagonal line D′ intersect perpendicularly. Each of the sixth connecting surfaces  12   f  is provided with four fourth recessed portions  15   f,  and every two said fourth recessed portions  15   f  are disposed diagonally. In this way, the connection between two adjacent building blocks is more stable and is not easy to loose. 
     Preferably, the first building block body has a size larger than the second building block body. Preferably, an edge length of the first building block body is twice an edge length of the second building block body. A periphery of each of the third recessed portions  14   e  in the third connecting surface  11   e  and the fourth connecting surfaces  12   e  are evenly provided with four fourth recessed portions  15   e  that are in communication with the each of the third recessed portions  14   e  in the third connecting surface  11   e  and the fourth connecting surfaces  12   e,  which can increase the deformation amounts of the third recessed portions  14   e  and the fourth recessed portions  15   e,  so that it is easier for the projecting portions to be inserted into the third recessed portions  14   e  and the fourth recessed portions  15   e.    
     When any two first building blocks are connected, two first projecting portions  13   e  on the third connecting surface  11   e  of a first first building block bodies can be respectively inserted into two third recessed portions  14   e  in any one of the fourth connecting surfaces  12   e  of a second first building block bodies. Alternatively, the two third projecting portions  13   e  on the third connecting surface  11   e  of the first first building block bodies can be respectively inserted into the two third recessed portions  14   e  in the third connecting surface  11   e  of the second first building block bodies, so that the two first projecting portions  13   e  on the third connecting surface  11   e  of the second first building block bodies can be respectively simultaneously inserted into the two third recessed portions  14   e  in the third connecting surface  11   e  of the first first building block bodies. A building block toy connected in this way has no first projecting portion  13   e  on its surfaces. 
     When any two second building blocks are connected, two second projecting portions  13   f  on the fifth connecting surface  11   f  of a first second building block bodies can be respectively inserted into two fourth recessed portions  15   f  in any one of the sixth connecting surfaces  12   f  of a second second building block bodies. Alternatively, the two second projecting portions  13   f  on the fifth connecting surface  11   f  of the first second building block bodies can be respectively inserted into the two fourth recessed portions  15   f  in the fifth connecting surface  11   f  of the second second building block bodies, so that the two second projecting portions  13   f  on the fifth connecting surface  11   f  of the second second building block bodies can be respectively simultaneously inserted into the two fourth recessed portions  15   f  in the fifth connecting surface  11   f  of the first second building block bodies. A building block toy connected in this way has no second projecting portion  13   f  on its surfaces. 
     When a first building block and a second building block are connected, two second projecting portions  13   f  on the fifth connecting surface  11   f  of the second building block body can be respectively inserted into two fourth recessed portions  15   e  in any one of the fourth connecting surfaces  12   e  of the first building block body. Alternatively, the two second projecting portions  13   f  on the fifth connecting surface  11   f  of the second building block body can be respectively inserted into the two fourth recessed portions  15   e  in the fifth connecting surface  11   e  of the first building block body. 
     Preferably, the first projecting portions  13   e  are in a columnar structure formed by a plurality of sheet-like structures arranged at intervals; and the second projecting portions  13   f  are in a hollow square columnar structure, so that the first projecting portions  13   e  and the second projecting portions  13   f  are more easily deformed and the connection among building blocks is more labor-saving. 
     Thus, in the connecting structure of building blocks according to Embodiment  10  of the present invention, the first projecting portions  13   e  of the first building block body can be inserted into the third recessed portions  14   e  of one adjacent first building block body, and the second projecting portions  13   f  of the second building block body can be inserted into the fourth recessed portions  15   f  of one adjacent second building block or into the fourth recessed portions  15   e  of one adjacent first building block body. The first building block body and the second building block body can be connected to each other, so that there may be a variety of connecting possibilities, which enriches the connection forms among different types of building blocks and improves interestingness. 
     The technical features of the above-mentioned embodiments can be arbitrarily combined. In order to simplify the description, all possible combinations of the technical features in the above-mentioned embodiments are not described. However, as long as there is no contradiction in the combinations of these technical features, the combinations should be regarded as within the scope of this description. 
     The above are only the preferred embodiments of the invention. It should be noted that, several improvements and replacements can be made by those skilled in the art without departing from the technical principles of the invention. These improvements and replacements also fall into the protection scope of the invention.