Dobbies

Claim 1

A dobby with at least one needle for reading a perforated pattern card comprising, two driving means applying force to the reading needle sequentially, a first one of said means having means to apply a low value force to initiate the reading of the pattern card by the reading needle and initiate entry of said needle into a perforation, and a second means effective to apply force to the reading needle to continue insertion of said needle into a perforation when there is a slight movement of the needle into a perforation of the pattern card, the second driving means having means comprising a positively driven lever mechanism applying a greater force than the force of the first system to move the needle deeper into the perforation of the pattern card, a needle holder, said lever mechanism comprising a double lever having first and second lever arms driven so that it swings to and fro, a cam on the needle holder, the cam and lever arms being so arranged that the first arm, during the movement of the double lever away from the pattern card lifts the needle out and away from the pattern card against the force of the weaker first means, and during its movement toward the pattern card, releases the needle for reading the pattern card, and the second arm entrains the needle or its holder, during its movement towards the pattern card, if the needle has moved slightly into a perforation which has been read, and the cam having a face cooperating with the second arm to allow during this movement the arm to slide past the cam and does not entrain the needle or its holder, if the needle only rests on the pattern card and has not read any perforations.