CNC controlled buttonhole sewing machine

#1. Field of the Invention

#The invention relates to a CNC controlled buttonhole sewing machine, comprising a needle drivable via an arm shaft; an x-y table, which is displaceable placeable in an x direction by an x drive and in a y direction by a y drive, and which supports a first and a second work piece clamp mounted for displacement relative to each other, and which comprises a pneumatically actuated displacement drive for displacement of the work piece clamps relative to each other from an initial position of spread by a length of spread into a final position of spread; and a control unit for control of the drives.

#2. Background Art

#Details of the invention will become apparent from the ensuing description of three exemplary embodiments, taken in conjunction with the drawing.

#FIG. 1 is a side view of a buttonhole sewing machine;

#FIG. 2 is a partial plan view of an x-y table of the sewing machine in accordance with the arrow II of FIG. 1;

#As seen in FIG. 1, a buttonhole sewing machine is C shaped, having a top arm 1, a bottom base plate 2 in the form of a casing and an approximately vertical standard 3 that unites the two. An arm shaft 4 is conventionally lodged in the arm 1; it is drivable by a motor 5 which is only roughly outlined in FIG. 8. The actuation of a vertically displaceable needle bar 6 with a needle 7 and a jogging drive therefor customarily derive from the arm shaft 4.

#Disposed on the base plate 2 is an x-y table 8 which is a cross slide that is movable in two horizontal coordinate directions, namely the x and the y direction. The x-y table 8 is of conventional design as known for example from U.S. Pat. No. 6,095,066. Actuation of the x-y table 8 takes place by drives roughly outlined only in FIG. 8, namely an x drive 9 and a y drive 10, which are electric positioning motors, preferably stepper motors, or controllable D.C. motors.

#A two-piece supporting plate 11a, 11b is disposed on the x-y table 8. The sectional supporting plate 11a on the left—seen in the y direction—is fixed to the x-y table 8 by positioning devices 12, 12′. The positioning devices 12, 12′ are formed by recesses in the sectional supporting plate 11a and by pins which are tightly mounted on the x-y table 8. The sectional supporting plate 11a is non-displaceable in relation to the x-y table 8. The sectional supporting plate 11b on the right—seen in the y direction—is supported for displacement in the x direction on the x-y table 8. The top surfaces of the sectional supporting plates 11a, 11b are on a joint x-y plane.