Card switching apparatus for dobby

A card switching apparatus for a dobby comprising:

• a first gear securely mounted on a rotary shaft of a cylinder with a card, which is supported on a bracket mounted for rocking motion around a first shaft;
• a driving gear securely mounted on an input shaft driven in response to a loom;
• an idle gear supported on a second shaft, said idle gear being disposed between the first gear and the driving gear and transmits the rotation of the input shaft to the cylinder;
• an eccentric crank lever being connected to and supporting a second shaft of the idle gear thereon;
• and
• a motor for moving the crank lever,
• a second gear supported on the bracket and engaged with the first gear,
• wherein said idle gear comprises a third gear which is supported on the second shaft extending through a cam slot formed in a cam plate and is in meshed engagement with the second gear and the driving gear, said cam plate being secured to a frame,
• wherein said eccentric crank lever has a round hole formed at the end portion opposite the second shaft, and an eccentric disk is fitted in the round hole of the crank lever and is secured to a shaft of the motor, whereby said crank lever is displaced to move the second shaft along the cam slot in response to a rotational angle of the shaft of the motor;
• wherein said cam slot consists of a levelling cam slot formed to extend from a position corresponding to the forward rotation position of the second shaft for normal operation to a first arc centering around the center of the driving gear and another reverse rotating cam slot formed contiguously to the levelling cam slot and extending from the position to a second arc centering around the center of the second gear.