Attachment mechanism

Abstract

An assembly for mounting a visor on a helmet includes a visor assembly having a lens and a fastening element with a pair of latching prongs each with a resiliently displaceable prong end; a casing attached to the helmet and having a pair of channels each for receiving the a latching prong and a pair of fixtures, each fixture for engaging a respective prong end when displaced outwardly; and a lock having a pair of locking prongs, each locking prong being insertable into one channel from an opposite end as the latching prongs and each locking prong having a locking prong end that is positionable under a respective latching prong to prevent displacement of the latching prong end inwardly to disengage from the respective fixture.

1 . A fastener comprising:
 a latch including first and second latching prongs, the first latching prong having a first resiliently displaceable prong end, and the second latching prong having a second resiliently displaceable prong end;   a casing to receive the latch including the first and second latching prongs, and the casing including first and second fixtures to engage the first and second prong ends respectively when the prong ends are displaced outwardly; and   a lock positioned at least partially in the casing and positionable to be adjacent to each of the first and second latching prongs in a locked position to prevent an inward displacement of the prong ends that is sufficient to disengage the prong ends from the fixtures;   wherein the lock is biased toward the locked position.   
     
     
         2 . A fastener as in  claim 1 , further comprising a spring, wherein the spring biases the lock toward the locked position. 
     
     
         3 . A fastener as in  claim 2 , wherein the spring is attached to the casing and to the lock, and the spring pulls on the lock to bias the lock toward the locked position. 
     
     
         4 . A fastener as in  claim 1 , wherein the lock comprises first and second locking prongs, the first locking prong positionable adjacent to the first latching prong, and the second locking prong positionable adjacent to the second latching prong. 
     
     
         5 . A fastener as in  claim 4 , wherein each of the first and second locking prongs comprises a tapered engagement end. 
     
     
         6 . A fastener as in  claim 1 , wherein the lock includes a locking detent that is releasably engaged to the casing to hold the lock in the locked position. 
     
     
         7 . A fastener as in  claim 1 , wherein:
 the first and second fixtures comprise first and second edge portions of the casing which define first and second openings;   the casing includes first and second channels to receive the first and second latching prongs respectively;   the latching prongs deflect inwardly to enter the channels; and   when fully inserted, the latching prongs move outwardly such that ends of the latching prongs enter the openings with the edge portions preventing separation of the latch from the casing.   
     
     
         8 . A fastener as in  claim 1 , wherein the casing is attached to a helmet.