Toy building block set

Abstract

A toy building block set includes a socket block piece and at least one of first and second plug block pieces. The socket block piece has a socket wall body and at least one engaging hole of a regular polygonal shape. Each of the first and second plug block pieces has a plug body and at least one polygonal insert plug configured to be inserted into and in frictional engagement with the engaging hole with a first frictional force to permit rotation of the plug block piece relative to the socket block piece by a forcible torque and to keep a predetermined angle of the plug block piece relative to the socket block piece when the forcible torque is removed. The plug body is partially inserted into and in frictional engagement with the engaging hole with a second frictional force larger than the first frictional force.

What is claimed is: 
     
         1 . A toy building block set comprising:
 a socket block piece having a socket wall body and at least one engaging hole which is formed in said socket wall body and bordered by an inner peripheral wall that surrounds a rotating axis normal to said socket wall body, said inner peripheral wall having a cross-section which is of a regular polygonal shape; and   at least one of first and second plug block pieces having a plug body and at least one polygonal insert plug which extends from said plug body, said polygonal insert plug having an outer peripheral wall with a cross-section which is of a regular polygonal shape to be inserted into said engaging hole in an extending direction parallel to the rotating axis and in frictional engagement with said inner peripheral wall with a first frictional force that is dimensioned to permit rotation of said plug block piece relative to said socket block piece about the rotating axis by a forcible torque and to keep a predetermined angle of said plug block piece relative to said socket block piece when the forcible torque is removed, said plug body being partially inserted into said engaging hole and in frictional engagement with said inner peripheral wall with a second frictional force which is larger than the first frictional force.   
     
     
         2 . The toy building block set as claimed in  claim 1 , wherein said engaging hole penetrates through said socket wall body. 
     
     
         3 . The toy building block set as claimed in  claim 2 , wherein said first plug block piece has two of said polygonal insert plugs which extend from said plug body and away from each other. 
     
     
         4 . The toy building block set as claimed in  claim 2 , wherein said second plug block piece has a circular insert plug which extends from said plug body and away from said polygonal insert plug, said circular insert plug having an outer peripheral wall with a cross-section which is of a circular shape to be inserted into said engaging hole in the extending direction and in frictional engagement with said inner peripheral wall with a third frictional force that is dimensioned to permit rotation of said second plug block piece relative to said socket block piece about the rotating axis by a forcible torque and to keep any angle of said second plug block piece relative to said socket block piece when the forcible torque is removed, and that is smaller than the second frictional force. 
     
     
         5 . The toy building block set as claimed in  claim 2 , wherein said at least one of said first and second plug block pieces has a tubular hole which extends through said plug body and said polygonal insert plug in the extending direction. 
     
     
         6 . The toy building block set as claimed in  claim 5 , wherein said at least one of said first and second plug block pieces has a plurality of splits which are formed in and extend through said outer peripheral wall to be in communication with said tubular hole and are angularly displaced from each other so as to permit resilient engagement of said outer peripheral wall with said inner peripheral wall of said socket block piece. 
     
     
         7 . The toy building block set as claimed in  claim 6 , further comprising a retaining piece which has a retaining shank that extends to be inserted into said tubular hole in the extending direction to decrease resilient deformation of said polygonal insert plug, and a head that is disposed on and extends radially and outwardly from an end of said retaining shank to abut against said polygonal insert plug. 
     
     
         8 . The toy building block set as claimed in  claim 7 , wherein said retaining piece has a plurality of filling ribs which are formed on said retaining shank to be respectively filled in said splits when said retaining shank is inserted into said tubular hole. 
     
     
         9 . The toy building block set as claimed in  claim 5 , further comprising a rotating shaft which is configured to be inserted into said tubular hole of said at least one of said first and second plug block pieces so as to operatively drive rotation of said at least one of said first and second plug block pieces relative to said socket block piece about the rotating axis. 
     
     
         10 . The toy building block set as claimed in  claim 9 , wherein each of said tubular hole and said rotating shaft has a cross-section of a polygonal shape. 
     
     
         11 . The toy building block set as claimed in  claim 1 , further comprising an adaptor block piece, said adaptor block piece having a curved wall body, at least one adaptor engaging hole which is formed in said curved wall body and which has a cross-section of a regular polygonal shape to allow insertion and frictional engagement of said polygonal insert plug of said at least one of said first and second plug block pieces, and at least one adaptor insert plug which projects from said curved wall body and which has a cross-section of a regular polygonal or circular shape to be inserted into and frictionally engaged with said engaging hole of said socket block piece. 
     
     
         12 . The toy building block set as claimed in  claim 11 , wherein extending directions of said adaptor insert plug and said adaptor engaging hole are transverse to each other. 
     
     
         13 . The toy building block set as claimed in  claim 1 , wherein said socket wall body of said socket block piece is in the form of an elongated plate which extends in an elongated direction, and has a plurality of said engaging holes which are spaced apart from each other along the elongated direction. 
     
     
         14 . The toy building block set as claimed in  claim 1 , wherein said cross-section of said polygonal insert plug is octagonal. 
     
     
         15 . The toy building block set as claimed in  claim 2 , wherein said inner peripheral wall of said engaging hole has a middle wall portion extending in a direction of the rotating axis, two larger-diameter wall portions respectively extending from two ends of said middle wall portion, and two shoulder portions each interposed between said middle wall portion and a respective one of said larger-diameter wall portions, said polygonal insert plug of said at least one of said first and second plug block pieces having a plurality of flange sections formed at a terminal end thereof such that, when said polygonal insert plug is inserted into said engaging hole, said flange sections are received within one of said larger-diameter wall portions and abut against a corresponding one of said shoulder portions, and said plug body is partially received within the other one of said larger-diameter wall portions and abuts against a corresponding one of said shoulder portions. 
     
     
         16 . The toy building block set as claimed in  claim 15 , wherein said inner peripheral wall of said engaging hole has a plurality of slots formed in each of said larger-diameter wall portions and each extending in the direction of the rotating axis, said plug body of said at least one of said first and second plug block pieces having a plurality of keys which are formed thereon and angularly displaced from each other so as to be engaged with said slots, respectively.