Sewing machine with feed dog dropping system

A sewing machine, comprising a feed dog vertically displaceable between an upper operative position and a lower inoperative position and horizontally movable for feeding;

• a fabric feed regulator adjustably operative to control the horizontal feeding movement of said feed dog;
• a control motor having a control shaft operatively connected with said fabric regulator to adjustably set the latter in accordance with a selected stitch pattern;
• control means connected with said control shaft and turnable by the latter within a predetermined range in two opposite directions;
• a cam element displaceable from an inoperative position to an operative position by said control means during turning of the latter in one of said directions;
• a cam follower normally engaging said cam element and displaceable from an inoperative position to a set position by said cam element during displacement of said cam element from its inoperative position to its operative position, said cam follower in said set position being further displaceable to an operative position by said control means during turning of the latter in the other of said directions;
• and transmitting means operatively connected with said cam follower and said feed dog and operated by said cam follower during displacement of said cam follower from its set position to its operative position to displace said feed dog from its upper operative position to its lower inoperative position.