Dobby dobby of rise and fall of negative action

摘要

In a double lift negative dobby machine, a balance lever (8) is pivotally attached to a jack-lever, and driving members (16, 17) disposed respectively in front of upper and lower ends of the balance lever (8) reciprocate in opposite phases with each other. Driven hook levers (10, 11) are pivotally attached to the upper and lower ends of the balance lever (8), and driving hook levers (18,19) opposite to the driven hook levers (10, 11) are pivotally attached to the driving members (16, 17). Command levers rotate the driving hook levers (18, 19) to become engaged with the driven levers (10, 11) respectively. Flat surfaces (10b, 11b) provided on the driven hook levers (10, 11) respectively push against plane contact surfaces of stops (12, 13) which are fixed to the machine casing. When the driven hook level (10, 11) begin to be pulled by the driving hook levers (18, 19) respectively, the driven hook levers (10, 11) are moved in perpendicular direction to the flat surfaces (10b, 11b), the engaging portion of the driven hook lever (10) with the driving hook lever (18) is on a line interconnecting the pivotal axes of both hook levers (10 and 18), the engaging portion of the driven hook levers (11) with the driving hook lever (19) is on a line interconnecting the pivotal axes of both hook levers (11 and 19) and the rocking center of the pivot portion (7) of the jack lever (5), on which the balance lever (8) is disposed, is arranged above or below the rotation axial center (6) of the jack-lever (5) on a vertical line passing through the axial center.