Abstract: A sewing machine with a drive mechanism for a fabric holder is provided with a first carriage and a second carriage, the second carriage being connectable to the fabric holder. A first motor is provided for driving the first carriage via a first toothed belt and a second motor is provided for driving said second carriage via a second toothed belt, the second toothed belt forming part of a toothed belt drive. A first, stationary rail is provided extending in parallel to the longitudinal axis of the sewing machine, the first carriage being arranged on the first, stationary rail. A second rail is provided forming a transversely extending rail which is carried by the first carriage and extends at right angles to the longitudinal axis of the sewing machine, the second carriage being on the second rail, and the second rail forming a support for the toothed belt drive.

Abstract: A program-controlled sewing or embroidery machine comprising a stitch-forming device (2), an integrated microcomputer (4), at least one memory (16, 17) and at least one data interface (5), as well as a keyboard (12) and a display (11) for entering and monitoring or checking values for program control.

Abstract: An embroidery frame, comprising a closed inner frame and an outer frame open at a point and a clamping device provided on the outer frame with one laterally projecting projection each at each of the two ends of the outer frame. A stud is provided that can be fixed at one projection and a screwing device is provided that cooperates with the stud and is supported at the other projection. The stud is displaceably guided within one projection at a closely spaced location from the outside of the frame and is supported with a head on a stop face of the projection. The other end of the stud is rigidly connected to a sliding block, which is longitudinally displaceably accommodated within a guide provided in the other projection. A tie rod is led out of the other projection extending obliquely toward the outside of the frame. The tie rod is pivotably arranged at the sliding block.

Abstract: In a process and device for monitoring a residual amount of hook thread in a double thread lockstitch sewing machine, a bobbin is used, which is divided into a large clamber and a small chamber due to the arrangement of a middle flange, wherein the small chamber accommodates the residual amount of thread. An abrupt reduction in the speed of rotation of the bobbin, n.sub.S, takes place dating sewing at the time of the transition from the principal to the residual amount of thread as a consequence of the abrupt change in the thread pull-off site in the bobbin.

Abstract: A catch thread device is provided for a sewing machine with a scanning element controlled by the upper thread in the rhythm of sewing. The scanning element triggers a signal for the operator and/or for switching off the drive of the sewing machine via an electronic control circuit in the case of a thread break. The catch thread device includes a support fastened to the housing in the sewing machine as well as a pivotable switching lever. The pivotable switching lever is pretensioned and mounted in the support and is connected to the scanning element extending into the course of the upper thread between an eye of the needle and a thread guide of a thread lever of the sewing machine. The scanning element is connected to a magnet which is arranged adjacent to a Hall IC (integrated circuit) fastened to the support wherein the Hall IC is connected via lines to the control circuit for evaluating the signals triggered by the magnet in the Hall IC during the movement of the switching element.

Abstract: A device is provided for detachably fastening an embroidery frame, slidingly arranged on a support surface, to a drive member of a feed mechanism of a sewing or embroidery machine. The device includes a coupling device acting in a positive-locking manner and nonpositively acting locking device. Two coupling pins, which are located at mutually spaced locations from one another in the horizontal direction and carry a head each, are fastened to the said embroidery frame. A holding element is fastened to the drive member and contains two elongated holes, which extend in parallel to the said support surface of the machine and whose height corresponds to the diameter of the said coupling pins. A free space is provided in the area of the elongated holes for the heads of the said coupling pins.

Abstract: A presser foot is provided with a detachably arranged base. The base contains a needle passage opening and includes a plurality of guide grooves located at mutually spaced locations from one another on the under side of the base. The guide grooves are used for preparing pipings which extend in parallel to one another in the fabric. The middle guide groove extends centrally to the needle passage opening. The width of the needle passage opening essentially corresponds to a maximum overstitch width of the needle of a zig-zag sewing machine. A second and third guide groove extend, in a short distance, to the side of the needle passage opening. A fourth guide groove is provided with a distance from the middle guide groove which exactly corresponds to the mutual distance between the second and third guide grooves.

Abstract: A sewing unit with a thread-guiding needle, with a lock stitch hook with a thread reserve, with a fabric holder that can be moved in any direction relative to the needle axis, and with a fabric presser foot with a needle passage opening, which can be placed on the fabric in cycle with the movement of the needle. Loop or twist stitches are formed in an area of the possible directions of movement of the fabric holder. To pull these stitches reliably into the fabric, the needle passage opening is asymmetrically widened beginning from the site of the needle passage, namely, elliptically beginning from a part semi-circularly surrounding the site of the needle passage in one design, and angularly with an arched limiting edge connecting the legs of the angle in another design.

Abstract: A sewing unit with a feed device for a fabric holder with support elements that can be moved along a guide and are connected to a drive each for feed means acting on the fabric holder. A fabric being sewn can be transported to or removed from the sewing machine by the feed device over any desired distance and the feed movement of the fabric being sewn can be brought about without problems during passage through the stitch formation site of the sewing machine even at very high stitch frequency because of the favorable dynamic properties. The guides are arranged in the same direction, and the support elements can be driven synchronously for a movement of the fabric holder in parallel to the guides, and at mutually different velocities for a movement in a direction deviating from the direction.

Abstract: A cable connection between a PC and a sewing machine for transmitting data in the form of different voltage levels, wherein the cable connection for connection to the PC has an RS 232 C port and the sewing machine has a TTL port. A level converter is integrated in the cable connection, preferably in the connection jack to the RS 232 C port. The level converter has a switching transistor controllable by the sending pole of the TTL port and a switching transistor controllable by the sending pole of the 232 port for connecting the corresponding receiving pole to a voltage potential which it is able to receive.

Abstract: In a process and a device for shortening the needle thread end at the beginning of sewing and at the end of sewing in two-thread lockstitch sewing machines, the catch thread device (23) of an already existing thread-cutting device (22; 60; 90) is moved into its thread-catching position during the first stitch formation cycle, and it is ensured, either by the selection of a suitable point in time for moving the catch thread device (23) or by a compressed air flow discharged from a compressed air line (81), that at least the reserve-side leg of the needle thread loop will be caught by the catch thread device (23). Part of the needle thread end is cut off during the return movement of the catch thread device (23) into its starting position. Furthermore, the needle thread is clamped either under a leaf spring (44), or is pushed by a sufficiently large feed step under the pressure foot, and is thus held in a frictionally engaged manner.

Abstract: A process for determining coordinate values of touchdown sites of a needle for forming sewing patterns with an electronically controlled sewing machine, which is equipped with a feed dog performing only relatively small amounts of displacement and with a needle pivotable in one direction of displacement of the feed dog. The coordinate values for a straight seam section, the consecutive touchdown points of the needle, are determined when the maximum amount of feed of the feed dog in the X coordinate direction and/or the sum of the maximum amount of the lateral movement of the needle which is possible at a given needle position and the maximum amount of feed of the feed dog in the Y coordinate direction is exceeded. The seam section is subdivided by equidistant intermediate touchdown sites, the distances between which in the direction of movement of the needle are composed of a constant percentage of the lateral movement of the needle and of a constant feed percentage of the feed dog.

Abstract: To scan the material being sewn (30, 31) in a sewing machine in an annular area around the presser foot, an annular lens system (25) is provided, which images a circle (33) concentrically surrounding the presser foot in the plane (A) of the material being sewn onto the light inlet ends of a likewise annularly arranged plurality of optical fibers (26). The optical fibers (26) lead, in an individual assignment, to the individual light-receiving elements of a photoelectric sensor line of a line camera, which sensor line can be read cyclically.

Abstract: A process and device for monitoring the bobbin thread on stitch-forming machines, on the bobbin of which a residual amount of thread is wound in a winding direction opposite the direction of winding of the principal amount of thread, is to ensure that a first control function will be generated at the beginning of consumption of the residual amount of thread, and a second control function is generated nearly without delay in the case of thread end or thread break. To achieve this, two signal patterns are received with a phase shift from a bobbin acting as a signal generator, and the first signal function is generated in the case of a deviation of the actual phase shift from the desired phase shift. If only one signal pattern is received, this first control function is also generated if its signal sequence deviates from a reference signal sequence. The second control function is generated if a stoppage of the bobbin lasts longer than a predeterminable number of stitches.

Abstract: A stitch forming machine is provided including a transducer for determining the tension present in a thread, wherein the thread tension assumes a higher value during stitch formation and the transducer provides a signal representing the tension level. The control is provided for evaluating the signal corresponding to the tension level. The control includes a comparator device for comparing a peak of the signal representing the tension level, which peak can be used to detect a malfunction, with a limit signal, corresponding to a limit tension. The comparator sends a signal to a switching device when a signal peak drops below the limit signal. The switching device may be connected to a shut-off device of the drive motor of the machine as well as one or more display elements. In this way, the machine may be stopped and the display element associated with a limit tension, below which the tension dropped by a switching device.

Abstract: A sewing machine is provided with an adjusting device for hem projection length sensors that can be moved relative to a cutting device, wherein the first hem projection length sensor is provided for sending a signal that brings about a cutting process for the front hem projection length, and the second of the sensors is provided for sending a signal that brings about a cutting process for the rear hem projection length. The length of the respective hem projection length and the width of an associated seamless fabric edge shall be able to be set depending on each other with minimum operator effort by the adjusting device both at the beginning and the end of the fabric. The adjusting device has a stop that is movable in the direction of feed for the front edge of the fabric for presetting the width of a seamless front fabric edge.

Abstract: The present invention pertains to a device for bending over a fabric, especially pockets to be sewn onto a fabric layer, with plates that are arranged in essentially parallel planes and cooperate with one another, a fabric support plate and bending plates, and with a pressing member that can be placed over the fabric, as well as with guide surfaces for the bending area of the fabric. It accomplishes the task of designing the device such that reliable and accurate bending of the fabric is made possible in a relatively simple manner, with only minor effort for adjustment. To achieve this, it has a pressing member (4), whose outer contour extends beyond the outer contour of the fabric support plate (1) in the area of the bending edges of the fabric support plate (1), and which has, at least in its edge zone, an elastically deformable holding member (15) for the fabric (2), which forms a guide surface for the fabric (2) in its bending area after the pressing member (4) has been placed over the fabric (2).

Abstract: Sewing machine with an upper feed mechanism is provided with a stroke-adjusting system in which the drive connection between the upper feed foot and the presser foot has a three-position control device for automatic adjustment of the height position of the upper feed system. This is preferably a hydraulic control device, whose hydraulic cylinder is subdivided by its adjusting piston into two chambers. A hydraulic difference measuring unit is provided wherein the two chambers 82a, 82b of the hydraulic cylinder 59 are connected via two antiparallel-connected pressure relief valves 71, 71'. Each pressure relief valve 71, 71' preferably consists of a spring-tensioned check valve R and a pressure-limiting valve D arranged downstream of it.

Abstract: A device for sewing together two fabric parts includes two pattern sensors and correcting means for determining and correcting misalignment of patterns on the fabric parts. Also, an additional image sensor (18) is provided, which scans the surface of the fabric (16) to be sewn at the site of an intermediate storage location (15) before this fabric is fed into the sewing machine. An image-processing device connected to this additional image sensor generates data on certain basic characteristics of the fabric pattern, such as color, contrast, lightness, register length, and angular orientation of the pattern components. From these characteristic data, a decision logic circuit determines setting data for the operating parameters of the devices used in the sewing machine for detecting and correcting a possible pattern misalignment during sewing.

Abstract: To recognize missed stitches during the operation of a sewing machine, a function, which represents the tensile force of a thread fed into a stitch-forming device depending on the angle of rotation of the main shaft, is scanned in its entirety during each revolution period of the main shaft for selected characteristics without regard to the location of this characteristic within the revolution period. The characteristics found are measured in order to obtain for each characteristic an analytical value that is compared with the corresponding analytical value from at least the last preceding revolution period to form the difference of the two analytical values. If this difference exceeds a predeterminable value, a decision corresponding to a missed stitch is made.