Abstract:
A five-by-five cube puzzle has a central shaft assembly mounted around by center blocks in predetermined numbers, first intermediate blocks, second intermediate blocks, first edge blocks, second edge blocks and corner blocks. Each center shaft of a multi-axis shaft unit of the central shaft assembly is combined with a movable inner shield. An outer shield is mounted on an outside of a corresponding inner shield with a spring and a screw. The inner shields and the outer shields are combined with the first intermediate blocks, second intermediate blocks, first edge blocks, second edge blocks and corner blocks to form the cube puzzle. Based on rotation of those blocks with respect to the relative movement between inner shields and outer shields and sufficient gap among each block and a corresponding inner shield and outer shield, smooth rotation of each block can be achieved without being affected by slightly skew block alignment.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a cube puzzle, and more particularly to a combined structure of an educational five-by-five cube puzzle having smooth rotation without unrotatable layers of blocks due to slightly skew block alignment. 
         [0003]    2. Description of the Related Art 
         [0004]    Conventional cube puzzles have different choices of cube sizes, such as 2×2×2, 3×3×3, 4×4×4 and larger cube sizes. As the cube sizes increase, the cube puzzles become more and more complicated in terms of the individual parts and the entire structure. Basically, each conventional cube puzzle has a central shaft and multiple blocks mounted on the central shaft and being pivotally rotatable with respect to the central shaft so as to generate diversified cube puzzles. Different colors and patterns are formed on the sides of each block. To solve a cube puzzle, users must keep rotating the blocks of the cube puzzle until each side of the cube puzzle shows a same color. 
         [0005]    The cube puzzles have been widespread and popular since the first appearance, and the combined structure thereof has been also developed for over three decades. However, as far as the 5×5×5 cube puzzles are concerned, although each layer of the cube puzzles is normally rotatable, the blocks of each layer of the cube puzzles to be rotated may be locked and unrotatable when the layer of blocks slightly deviates from their supposed position. Such phenomenon arises from excessive friction among the blocks and low manufacturing tolerances of the gaps between the blocks, and thus results in an awkward operation and unsmooth moves of the cube puzzles when the user attempts to solve the cube puzzles. 
       SUMMARY OF THE INVENTION 
       [0006]    An objective of the present invention is to provide a five-by-five cube puzzle having smooth rotation without unrotatable layers of blocks due to slightly skew block alignment. 
         [0007]    To achieve the foregoing objective, the five-by-five cube puzzle has a central shaft assembly, six center blocks, twenty four first intermediate blocks, twenty four second intermediate blocks, twelve first edge blocks, twenty four second edge blocks and eight corner blocks. 
         [0008]    The central shaft assembly has a multi-axis shaft unit, six inner shields and six outer shields. The multi-axis shaft unit has a base and six center shafts. The center shafts are formed on the base to respectively point to six mutually perpendicular directions. Each inner shield has an inner arch plate being square and detachably mounted around one of the center shafts. Each outer shield has an outer arch plate, a protruded shaft, a spring and a screw. The outer arch plate is square. The protruded shaft is formed on and protrudes inwardly from an inner side of the outer arch plate, and is centrally mounted through the inner shield. The spring is mounted in the outer shield. The screw is screwed into one of the center shafts through the spring so that a corresponding outer shield is movable along an axial direction of the protruded shaft and a stroke of movement of the outer shield is limited by an overall length of the screw. 
         [0009]    Each center block has a square plate centrally mounted on the outer arch plate of one of the outer shields. 
         [0010]    The first intermediate blocks are divided into six sets respectively mounted around the center blocks. Each first intermediate block has a square plate and a junction portion. One edge of the square plate adjoins a corresponding edge of the square plate of a corresponding center block. The junction portion detachably engages the outer arch plate of one of the outer shields, and has two ears respectively formed on and protruding from two sides of the junction portion, and each ear detachably abuts against an edge of the outer arch plate of a corresponding outer shield. 
         [0011]    Each second intermediate block is mounted between two adjacent first intermediate blocks, is diagonally adjacent to one corner of one of the center blocks and has a square plate and an assembly portion. Two edges of the square plate respectively adjoin two edges of the square plates of two adjacent first intermediate blocks. The assembling portion is formed on an inner side of the second intermediate block and detachably engages the outer arch plate of one of the outer shields. 
         [0012]    The first edge blocks are mounted between two adjacent first intermediate blocks on two adjacent sides of the cube puzzle. Each first edge block has a first piece and a connection portion. The first piece has two square faces perpendicularly connected. The connection portion is formed with the first piece and detachably connects with the inner arch plates of two adjacent inner shields and the outer arch plates of two adjacent outer shields. 
         [0013]    Each second edge block has a second piece and an engagement piece. The second piece is formed on one end of the second edge block and has two square faces perpendicularly connected with each other. The engagement piece is formed on the other end of the second piece and detachably connects with the inner arch plates of two adjacent inner shields and the outer arch plates of two adjacent outer shields. 
         [0014]    Each corner block is surrounded by three adjacent second edge blocks and has a corner body and a corner connection portion. The corner body has three square faces formed on one end of each corner block and perpendicularly connected with each other. The corner connection portion is formed on the other end of the corner body and detachably abuts against the inner sides of the inner arch plates of two adjacent inner shields. 
         [0015]    Each center shaft of a multi-axis shaft unit of the central shaft assembly is combined with a movable inner shield. An outer shield is mounted on an outside of a corresponding inner shield with a spring and a screw. The inner shields and the outer shields are combined with the first intermediate blocks, second intermediate blocks, first edge blocks, second edge blocks and corner blocks to form the cube puzzle. Based on rotation of those blocks with respect to the movable inner shields and outer shields and sufficient tolerance among each block and corresponding inner shield and outer shield, smooth rotation of each block can be achieved without being affected by slightly skew block alignment. 
         [0016]    Other objectives, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]      FIG. 1  is a first partially exploded perspective view of a five-by-five cube puzzle in accordance with the present invention; 
           [0018]      FIG. 2  is a second partially exploded perspective view of the five-by-five cube puzzle in  FIG. 1 ; 
           [0019]      FIG. 3  is a third partially exploded perspective view of the five-by-five cube puzzle in  FIG. 1 ; 
           [0020]      FIG. 4  is a perspective view of a central shaft assembly of the five-by-five cube puzzle in  FIG. 1 ; 
           [0021]      FIG. 5  is a partially exploded perspective view of the central shaft assembly of the five-by-five cube puzzle in  FIG. 4 ; 
           [0022]      FIG. 6  is a side view in partial section of the five-by-five cube puzzle in  FIG. 1 ; 
           [0023]      FIG. 7  is a fourth partially exploded perspective view of the five-by-five cube puzzle in  FIG. 1 ; 
           [0024]      FIG. 8  is a fifth partially exploded perspective view of the five-by-five cube puzzle in  FIG. 1 ; 
           [0025]      FIG. 9  is a sixth partially exploded perspective view of the five-by-five cube puzzle in  FIG. 1 ; 
           [0026]      FIG. 10  is a seventh partially exploded perspective view of the five-by-five cube puzzle in  FIG. 1 ; 
           [0027]      FIG. 11  is an eighth partially exploded perspective view of the five-by-five cube puzzle in  FIG. 1 ; 
           [0028]      FIG. 12  is a ninth partially exploded perspective view of the five-by-five cube puzzle in  FIG. 1 ; 
           [0029]      FIG. 13  is a tenth partially exploded perspective view of the five-by-five cube puzzle in  FIG. 1 ; 
           [0030]      FIG. 14  is an eleventh partially exploded perspective view of the five-by-five cube puzzle in  FIG. 1 ; and 
           [0031]      FIG. 15  is a perspective view of the five-by-five cube puzzle in  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0032]    With reference to  FIGS. 1 and 2 , a five-by-five cube puzzle has a central shaft assembly  1 , six center blocks  2 , twenty four first intermediate blocks  3 , twenty four second intermediate blocks  4 , twelve first edge blocks  5 , twenty four second edge blocks  6  and eight corner blocks  7 . 
         [0033]    With reference to  FIGS. 1 ,  2 ,  4  and  5 , the central shaft assembly  1  has a multi-axis shaft unit  10 , six inner shields  11  and six outer shields  12 . The multi-axis shaft unit  10  has a base  101  and six center shafts  102 . The center shafts  102  are formed on the base  101  to respectively point to six mutually perpendicular directions, namely front, rear, up, down, left and right. Each inner shield  11  has a square inner arch plate  110 , a shaft sleeve  111  and a through hole  112 . The shaft sleeve  111  is formed on and protrudes inwardly from an inner side of the inner arch plate  110 , and is mounted around one of the center shafts  102  of the multi-axis shaft unit  10 . The through hole  112  is centrally formed through the inner shield  11 . Each outer shield has a square outer arch plate  120 , a protruded shaft  121 , a cavity  122 , a receiving slot  123 , a spring  13  and a screw  14 . The protruded shaft  121  is formed on and protrudes inwardly from an inner side of the outer arch plate  120 , and is centrally mounted through the through hole  112  of the inner shield  11 . A free end of the protruded shaft  121  is detachably mounted in one of the center shafts  102  of the multi-axis shaft unit  10 . The cavity  122  is formed in a free end of the protruded shaft  121 . The receiving slot  123  is centrally formed through the outer shield  12  and axially formed in the protruded shaft  121  to communicate with the cavity  122 . The spring  13  is mounted in the receiving slot  123  of the outer shield  12  and abuts against an inner wall of the receiving slot  123 . The screw  14  is screwed into one of the center shafts  102  through the spring  13 . Each inner shield  11  can be slidably movable along the axial direction of a corresponding protruded shaft  121 . Each outer shield  12  can be moved outwardly and compress the spring  13 , and a stroke of movement of the outer shield  12  is limited by an overall length of the screw  14 . Accordingly, each outer shield  12  and a corresponding inner shield  11  can be relatively moved with respect to each other. In the present embodiment, the outer arch plate  120  of each outer shield  12  has a scarfed hole  124  formed in an outer surface of the outer arch plate  120  and communicating with the receiving slot  123  of the outer shield  12 . 
         [0034]    With reference to  FIGS. 1 to 3 , each center block  2  has a square plate  20  centrally mounted on the outer arch plate  120  of one of the outer shields  12  to cover the receiving slot  123 . In the present embodiment, the center block  2  further has a fitting protrusion  21  formed on and protruding from an inner side of the square plate  20  of the center block  2 , and fitted in the scarfed hole  124  of a corresponding outer arch plate  120 . 
         [0035]    With reference to  FIGS. 6 to 14 , the first intermediate blocks  3  are divided into six sets. Each set of the first intermediate blocks  3  are mounted on one side of the cube puzzle and is respectively mounted around one of the center blocks  2 . Each first intermediate block  3  has a square plate  30  and a junction portion  31 . One edge of the square plate  30  adjoins an edge of the square plate  20  of a corresponding center block  2 . The junction portion  31  has an engagement wall  311 , an engagement slot  310  and two ears  32 . The engagement wall  311  is L-shaped and is formed on and protrudes from an inner side of the square plate  30 . The engagement slot  310  is formed between the square plate  30  and the engagement wall  311 . The ears  32  are respectively formed on and protrude from two sides of the junction portion  31  and are parallel to the engagement slot  310 . An edge of the outer arch plate  120  of each outer shield  12  is inserted in the engagement slot  310  of a corresponding first intermediate block  3 . Each engagement wall  311  is detachably mounted between the outer arch plate  120  of a corresponding outer shield  12  and the inner arch plate  110  of a corresponding inner shield  11 . The ears  32  respectively and detachably abut against an edge of the outer arch plate  120  of a corresponding outer shield  12 . 
         [0036]    With further reference to  FIG. 2 , the second intermediate blocks  4  are divided into six sets. Each set of the second intermediate blocks  4  is mounted on one side of the cube puzzle. Each second intermediate block  4  is mounted between two adjacent first intermediate blocks  3  and diagonally adjacent to one corner of one of the center blocks  2 . Each second intermediate block  4  has a square plate  40  and an assembling portion  41 . Two adjacent edges of the square plate  40  respectively adjoin two edges of the square plates  30  of two adjacent first intermediate blocks  3 . The assembling portion  41  has an assembling protrusion  411  and an assembling slot  410 . The assembling protrusion  411  is L-shaped and formed on and protrudes from an inner side of the square plate  40 . The assembling slot  410  is formed between the square plate  40  and the assembling protrusion  411 . A corner of the outer arch plate  120  of each outer shield  12  and one ear  32  of one of the first intermediate blocks  3  detachably engages the assembling slot  410 . The assembling protrusion  411  is detachably mounted between the outer arch plate  120  of a corresponding outer shield  12  and the inner arch plate  110  of a corresponding inner shield  11 . 
         [0037]    Each first edge block  5  has a first piece  50  and a connection portion  51 . The first piece  50  has two square faces  500  perpendicularly connected. The square faces  500  of each first edge block  5  respectively adjoin the square plates  30  of two adjacent first intermediate blocks  3  on two adjacent sides of the five-by-five cube puzzle. The connection portion  51  is integrally formed with the first piece  50 , and has two flanges  511 , two inner wings  513  and two outer wings  512 . The flanges  511  are arch, are oppositely and respectively formed on and protrude from two edges of a free end of the connection portion  51 , and respectively and detachably abut against two inner sides of the inner arch plates  110  of two adjacent inner shields  11 . The inner wings  513  are arch, are respectively formed on and protrude from two sides of the connection portion  51 , align in a direction perpendicular to that of the flanges  511 , respectively and detachably abut against two edges of the adjacent inner arch plates  110  of two adjacent inner shields  11 . The outer wings  512  are arch, are respectively formed on and protrude from two sides of the connection portion  51 , are parallel to the inner wings  513 , and respectively and detachably abut against two corresponding ears  32  of two adjacent first intermediate blocks  3 . With the structure combining the inner wings  513 , the outer wings  512  of the first edge blocks  5 , the ears  32  of the first intermediate blocks  3  and the inner arch plates  110  and the outer arch plates  120  of the central shaft assembly  1 , a double-layer sphere is formed inside the five-by-five cube puzzle. 
         [0038]    Each second edge block  6  has a second piece  60  and an engagement piece  61 . The second piece  60  is formed on one end of the second edge block  6 , and has two square faces  600  perpendicularly connected with each other. The engagement piece  61  is L-shaped and formed on an inner end of the second piece  60 , and has a gap  611  formed between the second piece  60  and the engagement piece  61 . Each second edge block  6  adjoins one of the first edge block  5  and two adjacent second intermediate blocks  4 . The gap  611  is detachably mounted in by one of the outer wings  512  of a corresponding first edge block  5 , and the engagement piece  61  is detachably mounted between the corresponding outer wing  512  and inner wing  513  of one adjacent first edge block  5 . 
         [0039]    Each corner block  7  is surrounded by three adjacent second edge blocks  6 , and has a corner body  70  and a corner connection portion  71 . The corner body  70  has three square faces  700  formed on one end of the corner block  7  and perpendicularly connected with each other. The corner connection portion  71  has a pole  711  and a triangular plate  712 . The pole  711  is formed on an inner portion of the corner body  70 . The triangular plate  712  is formed on a free end of the pole  711 , and detachably abuts against the inner sides of the inner arch plates  110  of two adjacent inner shields  11 . 
         [0040]    With reference to  FIG. 15 , the five-by-five cube puzzle has five layers of blocks horizontally and vertically. With reference to  FIGS. 1 ,  2  and  5 , the center shafts  102  of the multi-axis shaft unit  10  are respectively mounted on the movable inner shields  11 . The inner shields  11  are respectively combined with the outers shield  12 , the first intermediate blocks  3 , the second intermediate blocks  4 , the first edge blocks  5 , the second edge blocks  6  and the corner block  7  to form a five-by-five cube puzzle as shown in  FIG. 15 . To be rotatable relative to the movable inner shields  11  and the outer shields  12 , the first intermediate blocks  3 , the second intermediate blocks  4 , the first edge blocks  5 , the second edge blocks  6  and the corner block  7  can be easily mounted between the inner shields  11  and the outer shields  12  with sufficiently large gaps between the inner shields  11  and the outer shields  12  arising from the relative movement between the inner shields  11  and the outer shields  12 , thereby enhancing the rotational smoothness in rotating each layer of blocks of the five-by-five cube puzzle. Accordingly, when the first intermediate blocks  3 , the second intermediate blocks  4 , the first edge blocks  5 , the second edge blocks  6  and the corner blocks  7  are operated and slightly deviate from straight or level positions at which those blocks are supposed to be located, and those blocks are not blocked or squeezed by the central shaft assembly  1  and can still be rotatable. 
         [0041]    The center blocks  2 , the first intermediate blocks  3 , the second intermediate blocks  4 , the first edge blocks  5 , the second edge blocks  6  and the corner blocks  7  can be formed with colors or patterns thereon. The colors or patterns on the six outer surfaces are different so as to be distinctly distinguished. 
         [0042]    Even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and function of the invention, the disclosure is illustrative only. Changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.