Bookrack

Abstract

A bookrack includes a book mounting plate for mounting an opened book to be read thereon, and the book mounting plate is supported to be capable of tilting to a left side and a right side in an opening direction of the book. A first spring member energizes the book mounting plate to tilt toward the right side, and a second spring member energizes the book mounting plate to tilt toward the left side. A structure is provided for keeping the book mounting plate in a normal position steadily under a state where energizing forces of the first and second spring members are balanced. The book mounting plate tilts to the left side or the right side due to a difference in weights between left and right spread portions of the book mounted on the book mounting plate, resisting against the energizing force from either of the first and second spring members.

1 . A bookrack comprising:
 a book mounting plate ( 1 ) for mounting a book ( 8 ) being opened in order to be read, said book mounting plate being supported to be capable of tilting to a left side or a right side in an opening direction;   a first spring member for energizing the book mounting plate ( 1 ) to tilt toward the right side; and   a second spring member for energizing the book mounting plate to tilt toward the left side, said first spring member and said second spring member being structured to keep the book mounting plate ( 1 ) in a normal position steadily under a state where energizing forces of the first and second spring members are balanced so that the book mounting plate ( 1 ) tilts to the left or right side by a difference of weights between a left spread portion ( 8   a ) and a right spread portion ( 8   b ) of the book ( 8 ) opened and mounted on the book mounting plate, resisting against the energizing force of one of the first and second spring members.   
   
   
       2 . A bookrack comprising:
 a book mounting plate ( 1 ) for mounting a book ( 8 ) being opened in order to be read, said book mounting plate being supported to be capable of tilting to a left side or a right side in an opening direction;   a first spring member for energizing the book mounting plate ( 1 ) to tilt toward the right side; and   a second spring member for energizing the book mounting plate to tilt toward the left side, said first spring member and said second spring member being structured to keep the book mounting plate ( 1 ) in a normal position steadily under a state where energizing forces of the first and second spring members are balanced, so that the book mounting plate ( 1 ) tilts to the left or right side by a difference of weights between a left spread portion ( 8   a ) and a right spread portion ( 8   b ) of the book ( 8 ) opened and mounted on the book mounting plate ( 1 ), resisting against the energizing force of one of the first and second spring members while acceding to the energizing force of the other of the first and second spring members.   
   
   
       3 . The bookrack according to  claim 1  or  claim 2 , comprising a pair of double torsion springs ( 4 ,  9 ) disposed symmetrically as the first and second spring members, wherein said double torsion spring includes a pair of coil portions ( 4   a,    9   a ) and a book mounting plate energizing portion ( 4   b,    9   b ) provided between the pair of the coil portions, when the book mounting plate ( 1 ) tilts to the left side or the right side due to the difference of the weights between the left spread portion ( 8   a ) and the right spread portion ( 8   b ) of the book ( 8 ) mounted on the book mounting plate, the book mounting plate energizing portion ( 4   b,    9   b ) of the first double torsion spring or the second double torsion spring ( 4 ,  9 ) is displaced in a lower direction and the pair of the coil portions ( 4   b,    9   b ) of the first double torsion spring or the second double torsion spring ( 4 ,  9 ) builds up torsion resilience and the book mounting plate ( 1 ) is supported with the torsion resilience, being energized to tilt toward the right side or the left side. 
   
   
       4 . The bookrack according to  claim 1  or  claim 2 , comprising tension coil springs ( 4 ′,  9 ′) disposed symmetrically as the first and second spring members, wherein the book mounting plate ( 1 ) is supported with tensile resilience of the second tension coil spring ( 9 ′) or the first tension coil spring ( 4 ′), being energized to tilt toward the right side or the left side as the book mounting plate ( 1 ) tilts to the left side or the right side due to the difference of the weights between the left spread portion ( 8   a ) and the right spread portion ( 8   b ) of the book ( 8 ) mounted on the book mounting plate ( 1 ). 
   
   
       5 . The bookrack according to  claim 1  or  claim 2 , further comprising a shaft ( 3 ) for fixing the first spring member and the second spring member thereto, for adjusting the energizing forces of the first and second spring members; and a left plate and a right plate ( 1   a,    1   b ) for receiving the energizing forces, wherein said shaft moves in an upper direction and a lower direction to increase and decrease the energizing forces against the left and right plates.