Butterfly Hinge

Abstract

A butterfly hinge is disclosed comprising a first bracket with an index pin, a second bracket pivotally connected to the first bracket and provided with a pin shaft, and a lever rotatably mounted on the second bracket via the pin shaft. One end of the lever features several inclined first gear notches, while the other end is connected to the second bracket by a spring so that a first gear notch snap-fits onto the index pin under the spring's force. The lever also includes an extension piece slidably movable along its length, with an end extending beyond the lever and provided with an inclined extension slot adapted to mate with the index pin. The second bracket rotates relative to the first up to or near 180° to allow the sofa back to fold onto or near the sofa base's top surface, thus reducing sofa volume for compact packaging and transportation.

1 . A butterfly hinge, comprising:
 a first bracket ( 1 ) provided with an index pin ( 11 );   a second bracket ( 2 ) pivotally connected to the first bracket ( 1 ) and provided with a pin shaft ( 21 ); and   a lever ( 3 ) rotatably mounted on the second bracket ( 2 ) via the pin shaft ( 21 ), the lever ( 3 ) having a plurality of inclined first gear notches ( 31 ) formed at one end and with another end of the lever ( 3 ) connected to the second bracket ( 2 ) via a spring ( 4 ) so that, under the elastic force of the spring ( 4 ), the first gear notch ( 31 ) can be snap-fit onto the index pin ( 11 );   wherein the lever ( 3 ) is further provided with an extension piece ( 5 ) that is slidably movable relative to the lever ( 3 ) along the longitudinal direction of the lever ( 3 ), the end of the extension piece ( 5 ) extending beyond one end of the lever ( 3 ) and being provided with an inclined extension slot ( 51 ) adapted to mate with the index pin ( 11 ).   
     
     
         2 . The butterfly hinge according to  claim 1 , wherein the lever ( 3 ) is provided with a sliding pin ( 32 ), and the extension piece ( 5 ) is provided, in a central portion of the extension piece ( 5 ), with a first linear sliding groove ( 52 ) extending along the length of the extension piece ( 5 ), the sliding pin ( 32 ) being received in the first linear sliding groove ( 52 ) to enable the extension piece ( 5 ) to be slidably mounted within the lever ( 3 ). 
     
     
         3 . The butterfly hinge according to  claim 2 , wherein the lever ( 3 ) is further provided with a blocking plate ( 6 ) that is slidably movable along the longitudinal direction of the blocking plate ( 6 ) and configured to block the first gear notch ( 31 ), the blocking plate ( 6 ) having a second gear notch ( 61 ) adapted to mate with the first gear notch ( 31 ) and a sealing portion ( 62 ) positioned adjacent to the second gear notch ( 61 ), such that when the blocking plate ( 6 ) is slid relative to the lever ( 3 ) so that the second gear notch ( 61 ) is offset from the first gear notch ( 31 ), the sealing portion ( 62 ) is positioned adjacent to an opening of the first gear notch ( 31 ) to prevent the first gear notch ( 31 ) from being snap-fit onto the index pin ( 11 ). 
     
     
         4 . The butterfly hinge according to  claim 3 , wherein the blocking plate ( 6 ) is provided, in a central portion of the blocking plate ( 6 ), with a second linear sliding groove ( 63 ) extending along the length of the blocking plate ( 6 ), the sliding pin ( 32 ) being received in the second linear sliding groove ( 63 ) to enable the blocking plate ( 6 ) to be slidably mounted within the lever ( 3 ), and wherein the end of the blocking plate ( 6 ) and the end of the extension piece ( 5 ) are respectively provided with a first positioning hole ( 64 ) and a second positioning hole ( 53 ) that are mutually adapted, so that when a positioning member ( 7 ) is inserted through the first positioning hole ( 64 ) and the second positioning hole ( 53 ), the blocking plate ( 6 ) and the extension piece ( 5 ) are fixed together, with the rear side of the first linear sliding groove ( 52 ) contacting the index pin ( 11 ) and the front side of the second linear sliding groove ( 63 ) contacting the index pin ( 11 ), thereby fixing both the blocking plate ( 6 ) and the extension piece ( 5 ) to the lever ( 3 ) with the sealing portion ( 62 ) positioned adjacent to the opening of the first gear notch ( 31 ). 
     
     
         5 . The butterfly hinge according to  claim 4 , wherein the blocking plate ( 6 ) is provided with an inclined edge ( 65 ) at the front end of the blocking plate ( 6 ), the inclination angle of the inclined edge ( 65 ) being the same as that of the extension slot ( 51 ). 
     
     
         6 . The butterfly hinge according to according to  claim 1 , wherein the first bracket ( 1 ) is provided with a bent first limiting plate ( 8 ) that, together with the first bracket ( 1 ), forms a limiting space ( 81 ), the index pin ( 11 ) being fixedly connected at both ends, one end to the first bracket ( 1 ) and the other end to the first limiting plate ( 8 ), and the lever ( 3 ) passing through the limiting space ( 81 ) and being slidably mounted therein. 
     
     
         7 . The butterfly hinge according to  claim 6 , wherein the edge of the first limiting plate ( 8 ) is further provided with a clearance groove ( 82 ). 
     
     
         8 . The butterfly hinge according to  claim 6 , wherein the inner surface of the first limiting plate ( 8 ) is provided with a first protrusion ( 83 ) for reducing a contact area and protruding inwardly, and the outer surface of the first bracket ( 1 ) is provided with a second protrusion ( 12 ) for reducing a contact area and protruding outwardly, the first protrusion ( 83 ) and the second protrusion ( 12 ) being disposed on opposite sides of the lever ( 3 ), with the lever ( 3 ) contacting at least one of the first protrusion ( 83 ) or the second protrusion ( 12 ). 
     
     
         9 . The butterfly hinge according to  claim 1 , wherein the other end of the lever ( 3 ) is provided with a hook hole ( 33 ), a first hook portion ( 41 ) at one end of the spring ( 4 ) is engaged with the hook hole ( 33 ), and the second bracket ( 2 ) is further bent to form a hook rod ( 23 ), with a second hook portion ( 42 ) at the other end of the spring ( 4 ) engaged with the hook rod ( 23 ). 
     
     
         10 . The butterfly hinge according to  claim 9 , wherein the hook rod ( 23 ) is provided on the outer side of the hook rod ( 23 ) with a hook slot ( 231 ) into which the second hook portion ( 42 ) is engaged.