Patent attributes
A control device (53) for a clutch assembly (11) of a dobby comprises a selecting finger (28) that is driven by an electromagnet (37). The selecting finger is rigidly connected to an armature (47) that has a curved armature section and a straight armature section. Together with an appropriately curved pole (45) of the magnetic circuit, the curved armature section forms an air gap (48) that is preferably not influenced by the pivot position of the selecting finger. The other pole (46) of the electromagnet (37) forms a preferably straight air gap (49), said air gap being variable and having a size that is a function of the pivot position of the selecting finger. Due to the existing lever ratios, the maximum width of the trapezoidal gap is substantially smaller than the path of the outer end of the selecting finger (28) between its two selection positions. The distance (A) between the pivot center (32) and the variable air gap (49) is substantially smaller than the length of the selecting finger (28).