Abstract: A buttonhole sewing machine comprises a top arm (1) with a needle (6) movable in up and down reciprocation and a base plate (2). A buttonhole cutting device (13) is provided, having a knife (36) which is disposed on the base plate (2) and comprises a straight cutting edge (37) that extends in the y direction and an eye cutting edge (38). A cutting block (15) cooperates with the knife (36). The knife (36) and the cutting block (15) are motor-adjustable one in relation to the other in the y direction.

Abstract: A sewing machine with a hook (8) that is drivable in rotation about a vertical axis comprises a bobbin case (21) with a lifter cam (31). A case lifter (33) is provided, having a sensing lever (40) and a lifter lever (32) that bears against a lifter cam (28). The sensing lever rests on a cam face (42) of an axial cam disk (39) which is mounted on the transmission shaft that actuates a hook-driving shaft (10).

Abstract: In a method of pulling the free end of a needle thread from the top to the bottom of at least one work piece upon a first stitch of a seam that is to be sewn, use is made of a sewing machine with at least one presser which can be placed on, and lifted off, the work piece. The needle thread is held tight while a needle-thread loop is extended by the tip of the hook so that the free end is pulled through the work piece. While the needle thread is held tight, the presser is at least partially relieved. The relief time increases as the thickness of the work piece grows.

Abstract: An eye-type buttonhole sewing machine comprises an x-y table with an x carriage which is guided on the sewing machine and on which a y carriage is displaceably guided, having a bearing plate. Actuation of the x carriage is effected by an x motor which is mounted on the sewing machine and directly coupled with the x carriage via a cam drive. Actuation of the y carriage is equally effected via an electric motor which is directly connected to the y carriage via a threaded spindle with a spindle nut and a sliding coupling.

Abstract: A buttonhole sewing machine for producing buttonhole seams with seam end sections of various shapes in a work piece comprises an input equipment for feeding buttonhole parameters; and a computer for calculating, from the buttonhole parameters, sewing data that determine the respective buttonhole geometry. It further comprises a memory for storing the computed sewing data and a key to be shifted into two key statuses, by means of which to trigger conversion of a buttonhole seam from a position to the left to a position to the right or vice versa, and storage thereof.

Abstract: A CNC controlled buttonhole sewing machine comprises work piece clamps with sliding drives for displacement from an initial position of spread, by a length of spread, into a final position of spread. The sliding drive is an electric positioning motor that is allocated to a work piece clamp. Further provision is made for a control unit with data storage, in which to store data, for displacement of the work piece clamp by a given length of spread.

Abstract: A buttonhole sewing machine comprises a buttonhole cutting device which includes a knife and a cutting block unit with several cutting blocks, one of which at a time being movable into a position of cooperation with the knife. The cutting blocks are mounted on an anvil that is stationarily joined to the sewing machine. The knife is movable from above against the anvil.

Abstract: A buttonhole sewing machine comprises a buttonhole cutting device which includes a knife and at least one cutting block that cooperates with the knife. Provision is made for a cutting drive for motion of the knife and the cutting block relative to each other by variable cutting force, the cutting drive comprising several linear drives which are connected in parallel and pneumatically actuated selectively.

Abstract: A buttonhole sewing machine comprises work piece clamps with a pneumatically actuated displacement drive for displacement relative to each other of the work piece clamps from an initial position of spread by a length of spread into a final position of spread. Only the first work piece clamp is displaceable relative to the x-y table. The displacement of the first work piece clamp is defined between two stop positions. A control unit stores data for triggering an x drive for reversed displacement of the x-y table by half the given length of spread.

Abstract: A buttonhole sewing machine comprises work piece clamps with displacement drives for displacement from an initial position of spread by a length of spread into a final position of spread. The work piece clamp comprises a supporting plate for accommodation of a work piece and a clamping plate mounted on the supporting plate. A clamping drive for actuation of the clamping plate supports itself on the supporting plate.

Abstract: A microprocessor-assisted sewing machine control equipment is flexibly applicable for controlling the sewing machine driving motor and further electric motors which are controlled independently of or in dependence on the rotary position. To this end, a control system is allocated to each electric motor, comprising an open-loop control unit for rotary-position-independent controlling, a closed-loop control unit for controlling the electric motor in dependence on the rotary position, and a selection unit. The selection unit couples for control either the closed-loop control unit or the open-loop control unit with the electric motor, depending on whether the electric motor is controlled by closed-loop control in dependence on the rotary position or by open-loop control independently of the rotary position.

Abstract: A sewing machine (1) with an overload clutch in the form of a friction clutch in the region of the handwheel (44), with a positioning motor (57), including a motor part (56) and a control part (55), and with a position transmitter (51) connected to the arm shaft (5). In the event of a blockage of the arm shaft (5), the control part (56) causes the positioning motor (57) to stop immediately and a fault warning to be output on an indicator panel (68) of the control apparatus (66). After the fault has been eliminated and the power supply has subsequently switched off and switched on again, the sewing machine (1) is ready for operation again.