Patents Assigned to Pfaff Industriemaschinen GmbH
  • Patent number: 5299518
    Abstract: Sewing machine with a lower feed dog, to which adjustable horizontal pushing motions are imparted by a driving cam via a stitch length regulating mechanism and vertical lifting movements are imparted by a driving cam via a lifting shaft. A lifting crank, with the free end of a follower mounted pivotably, can be swiveled out, in one position intended for sewing with a skipping feed into a slot of an oscillating crank mounted freely pivotably on the lifting shaft at a laterally spaced location from the lifting crank. In another position the follower is mounted into a slot of a holder, which is a rigid part of the housing and is arranged at a laterally spaced location from the lifting crank for bordering fabric edges with a band strip, fed in folded in the shape of a U around the fabric edges by a band strip bordering apparatus which participates in the horizontal feed motions of the feed dog.
    Type: Grant
    Filed: January 2, 1991
    Date of Patent: April 5, 1994
    Assignee: Pfaff Industriemaschinen GmbH
    Inventors: Albert Dusch, Karl-Heinz Walther
  • Patent number: 5237941
    Abstract: The object of the present invention is used to clamp the fabric to be embroidered in mechanical and manual embroidery.In embroidery hoops with an outer contour deviating from the circular shape, the task is to achieve uniform distribution of the contact pressures over the entire clamped surface between the inner hoop and the outer hoop. This task is accomplished by designing the shape of the cross section of the sections of the inner hoop between two axes such that the bending stiffness is essentially constant over the entire circumference of the inner hoop and the extension stiffness decreases continuously between two axes such that it reaches a minimum in the area of the smallest radius of curvature. The cross-sectional shape of the sections of the outer hoop between two axes is designed such that the extension stiffness between two axes changes in the direction opposite the change occurring in the inner frame.
    Type: Grant
    Filed: January 29, 1991
    Date of Patent: August 24, 1993
    Assignee: Pfaff Industriemaschinen GmbH
    Inventors: Werner Kraft, Paul Reinheimer
  • Patent number: 5199365
    Abstract: A thread monitoring arrangement for monitoring sewing thread at different areas along the path of the thread inducing a switching process for signalling or stopping the sewing process upon the occurrence of thread disturbance. The thread monitoring arrangement includes first sensor units positioned in an area between a thread reserve and an associated tensioning device. Second sensor units are provided in the area between the tensioning device and the associated stitch formation site for sending signals in the case of thread disturbance. A monitoring switching arrangement is provided, evaluating signals from the sensor units differently to induce different switching processes, either alerting the operator or stopping the sewing process, after a predetermined time or immediately.
    Type: Grant
    Filed: January 9, 1991
    Date of Patent: April 6, 1993
    Assignee: PFAFF Industriemaschinen GmbH
    Inventor: Kurt Arnold
  • Patent number: 5129171
    Abstract: A device for zone-by-zone tensioning of a flat material, especially an embroidery hoop. According to one possible solution, tensioning and clamping are brought about by a change in the circumferential length of a tensioning member that can be filled, by a gas or a fluid and another solution brings this about by twisting a tensioning member. To generate a strong tensioning force in the material, it is proposed in the first solution that the tensioning member be designed as a crease-free tube with a body. By selecting a cord angle of the body, tensioning can be achieved by increasing or decreasing the pressure and by increasing or decreasing the circumferential length. According to another solution, the tensioning member is designed as a torsion body that can be twisted in itself, preferably as a reinforced hollow body, which may also form a closed ring. To increase the tensioning force without unduly stressing the material, the device is designed with a rigid outer ring and a twistable inner ring.
    Type: Grant
    Filed: December 17, 1990
    Date of Patent: July 14, 1992
    Assignee: PFAFF Industriemaschinen GmbH
    Inventors: Conrad Arbter, Rolf Mahling
  • Patent number: 5120952
    Abstract: In a device for ascertaining the actual feed transmittted by an feed device f an industrial sewing machine to a material to be sewn, in which the number of the threads moved across a sensor arrangement is counted and the feed is calculated from the previously detected thread density, it is provided, for obtaining an exact thread count which is as independent as possible of the orientation of the sewn web, to place ahead of the photocell (10) of the sensor arrangement a rotating slit diaphragm (7) with at least one radially extending parallel limited slit (8). Preferably a second, rotationally adjustable, but fixed slit diaphragm (5) is provided, having slits (6) opening across a set angular sector, the rotatitng slit diaphragm (7) having a larger number of slits (8). Because of this the required rpm of the slit diaphragm (7) can be reduced. To avoid errors caused by the pattern of the material it is possible to operate in the relatively longer wave infrared spectrum.
    Type: Grant
    Filed: June 28, 1990
    Date of Patent: June 9, 1992
    Assignee: Durkopp Adler Aktiengesellschaft and PFAFF Industriemaschinen GmbH
    Inventors: Heribert Geisselmann, Manfred Frank
  • Patent number: 5113774
    Abstract: A thread cutting arrangement for sewing machines including an arrangement in which the tension of the thread is released in both directions of movement of an axially moveable drive mechanism such that the thread tensioning mechanism is opened when the needle thread is caught. The movement of the drive mechanism is transmitted via a one-way coupling so that the opening of the thread tensioning mechanism is limited to the duration of the after pawal of the needle thread.
    Type: Grant
    Filed: May 31, 1990
    Date of Patent: May 19, 1992
    Assignee: Pfaff Industriemaschinen GmbH
    Inventors: Albert Dusch, Karl-Heinz Walter
  • Patent number: 5113324
    Abstract: A lamp, which has a light source and a fiber-optic light guide that is led, over part of its length, in the housing of a sewing machine, and whose end piece projects from the housing, is to be arranged on the sewing machine such that a desired machine part can be illuminated without the work area and the field of view of the sewing machine operator being disadvantageously affected by the lamp. To achieve this, the end piece of the fiber-optic light guide is adjusted to the shape of a housing part and is received on the housing part, hidden by the side of the housing part facing away from the housing.
    Type: Grant
    Filed: December 19, 1990
    Date of Patent: May 12, 1992
    Assignee: Pfaff Industriemaschinen GmbH
    Inventor: Albert Dusch
  • Patent number: 5105751
    Abstract: The invention describes a process for carrying out a sewing operation with a sewing machine having a needle feed.In present sewing operations with a sewing machine having needle feed, defective stitches are often formed at the beginning, because the initial threads are not sufficiently clamped in the needle plate as a consequence of the elongated stitch hole. In the new process, the position of the needle prior to the beginning of sewing is displaced into an end zone of the stitch hole for performing a preselected number of initial stitches.
    Type: Grant
    Filed: May 4, 1990
    Date of Patent: April 21, 1992
    Assignee: PFAFF Industriemaschinen GmbH
    Inventors: Mathias Ulmen, Dieter Balzer, Heinrich Bungert
  • Patent number: 5103749
    Abstract: Patterns of two fabric layers are each recognized by a camera and the fabric layers are aligned to make these patterns agree in the transverse and longitudinal directions. According to the invention the influence of speed-related disturbance variables and pattern-related limitations during the generation of the signal is reduced. Two-dimensional images of the two fabric layers are recorded with a matrix camera each during a pause between feeds. The degree of congurence of the fabric layers according to the pattern is determined by two-dimensional cross-correlation analysis of the image points arranged in rows and columns. Aligning correction values are calculated from this degree. The edge distance of the fabric layers is determined with a section of the matrix sensors, which is a separate section in terms of evaluation. Based on the edge distance data, the lower fabric layer is adjusted to the correct distance continuously and the upper fabric layer is adjusted as needed.
    Type: Grant
    Filed: February 13, 1991
    Date of Patent: April 14, 1992
    Assignee: Pfaff Industriemaschinen GmbH
    Inventors: Heribert Geisselmann, Manfred Frank, Fritz Jehle, Erich Willenbacher
  • Patent number: 5095834
    Abstract: A sewing machine with a pivotable stitch formation unit is provided such that it is possible to form a straight stitch or a zigzag stitch seam without loop stitches occurring on the fabric. The fabric is displaceable under the needle without rotation because of a pivoting arrangement of the head and the shuttle holder. The arrangement allows the sewing machine to be switched over from a straight stitch to a zigzag stitch operation due to the adjustment of the oscillation frequency of the needle bar holder relative to the oscillation frequency of the needle bar by means of a multistep shifting gear.
    Type: Grant
    Filed: November 19, 1990
    Date of Patent: March 17, 1992
    Assignee: Pfaff Industriemaschinen GmbH
    Inventor: Oskar Braun
  • Patent number: 5091038
    Abstract: A plastic welding machine for producing connection seams with thermal plastic foil or thermal plastic film. The folding device includes a fix support plate and a folding plate which is provided with a U-shaped guide stop and can be pivoted back and forth between a feed position and a working position. Folding device can be folded open for introducing the edge strip of the material to be welded and then folded up where the edge strip is folded over in the shape of a U. A flat U-shaped guide sleeve is provided which may be pivoted into the folding device to produce lap joints on the two layers of the material to be welded.
    Type: Grant
    Filed: June 5, 1990
    Date of Patent: February 25, 1992
    Assignee: Pfaff Industriemaschinen GmbH
    Inventors: Peter Greller, Werner Schauss
  • Patent number: 5078068
    Abstract: A processing and sewing machine arrangement for preparing a seam which is uninterrupted on a seam side facing the needle of the sewing machine. The arrangement includes a shuttle thread disturbance detection arrangement and a control arrangement activating a stopping arrangement for stopping the sewing machine after the shuttle thread disturbance has been detected and after a stitch formation cycle which has been begun is completed. A regulating mechanism for setting stitch length is set into a reverse stitching mode by the control arrangement while the fabric being sewn is moved backward by one stitch length. After the shuttle thread has been fed in, thread is knotted by at least one stitch with the needle thread in the same insertion hole in which the old shuttle thread is located such that the old shuttle thread is correctly knotted with the needle thread.
    Type: Grant
    Filed: January 3, 1991
    Date of Patent: January 7, 1992
    Assignee: Pfaff Industriemaschinen GmbH
    Inventors: Walter Hager, Reinhold Dobner
  • Patent number: 5036780
    Abstract: The present invention pertains to a feed mechanism for a sewing machine for displacement-free, near-edge connection of two flexible layers of fabric in the direction of sewing. The device, which is to be used as an attachment, consists essentially of a driven, endless feeding arrangement guided in the horizontal direction and a plurality of receiving elements which are designed as clamps. The receiving elements include clamp lower parts arranged at a vertically spaced location from the fabric support surface and clamp upper parts that can be actuated like pushbuttons, as well as a pressing element acting on the clamp upper parts.With their edges that are to be connected, the fabric layers are fed into a flat feeding section and fixed and carried by a first clamp and continually fixed by consecutive clamps in the same position in the device, thus carried along the stitch formation site, and continuously released in the sewn state at a discharge point.
    Type: Grant
    Filed: May 17, 1990
    Date of Patent: August 6, 1991
    Assignees: PFAFF Industriemaschinen GmbH, Kochs Adler Aktiengesellschaft, Durokoppwerke GmbH
    Inventor: Fritz Krowatachek
  • Patent number: 5027730
    Abstract: Thread monitor for monitoring double lock stitch shuttles or hooks and chain stitch machine shuttles or loopers. During normal operation of the sewing machine, the shuttle thread is used as a reflection surface. The scattered light beams reflected by the thread enter photodetector 10 of the thread monitor 8. If the support surface 7, 28 is covered by thread, light beams will reach said photodetector 10, as a result of which a control circuit 12 connected to it issues a warning signal.
    Type: Grant
    Filed: November 1, 1989
    Date of Patent: July 2, 1991
    Assignee: Pfaff Industriemaschinen GmbH
    Inventors: Reinhold Dobner, Bernhard Mertel, Erich Willenbacher
  • Patent number: 5018465
    Abstract: The control circuit of a catch thread device has a counter for the main shaft of the swing machine. The counter counts the number of revolutions of the main shaft 26 during the reception of one of at least two signal intensities and is reset to its initial value when this signal intensity changes to the other signal intensity. When a predetermined maximum number of revolutions is reached, the counter emits a signal indicating a thread fault.
    Type: Grant
    Filed: April 9, 1990
    Date of Patent: May 28, 1991
    Assignee: Pfaff Industriemaschinen GmbH
    Inventors: Walter Hager, Edgar Butzen, Gunther Denuell, Kurt Arnold
  • Patent number: 5018460
    Abstract: An embroidering machine with a mounting device for individual embroidery hoops is provided with a design in which each individual embroidery hoop is always mounted with the same holding force and is always brought into the correct position for the start of the embroidery process. To ensure the three-point mounting of the individual embroidery hoop, which consists of an inner hoop and an outer hoop surrounding it, with the fabric to be embroidered located between them, the mounting device comprises two opposite holders, one of which has two contact surfaces enclosing an angle for fitted support surfaces of the outer hoop, and the other holder having a bow spring with a depression for a projection arranged on the outer hoop on the bisector of the angle enclosed between the contact surfaces.
    Type: Grant
    Filed: March 2, 1990
    Date of Patent: May 28, 1991
    Assignee: Pfaff Industriemaschinen GmbH
    Inventors: Lothar Schilling, Gottfried Schmidt
  • Patent number: 4996931
    Abstract: A sewing unit including a sewing machine and a transport device is provided in which the transport device is arranged so as to form a free access area at a front side of a sewing machine of the sewing unit such that a workpiece positioning may be executed without any impediment by the transport device. The transport device is connected at one end to a workpiece holder and is connected at another end to a bearing device which is set back from a front edge of the sewing unit. The transport device is moved along a path defined by a guide device and is moved by a driving device. Each of the guide device, drive device and bearing device being positioned away from a front end of the unit to define the free access area.
    Type: Grant
    Filed: June 2, 1989
    Date of Patent: March 5, 1991
    Assignee: Pfaff Industriemaschinen GmbH
    Inventor: Gunter Mall
  • Patent number: 4974534
    Abstract: A sewing machine with a housing having a base over which the workpiece is movable and with a drive shaft is rotatable in the housing. A needle bar is provided having a plurality of needles and is connected to the drive shaft and moved upwardly and downwardly. A feed mechanism is provided for moving the workpiece. A looper support has a looper for each needle and is connected to the drive shaft for swinging movement. A loop spreader connecting rod has a loop spreader for each needle and is movable transversely to the movement of the needles. A spreader drive shaft is connected to the drive shaft and has a drive crank eccentric which is oscillated by the rotation of the spreader drive shaft. An eccentric arm carried by the crank eccentric is connected to a rocking shaft via a clamp lever and the rocking shaft is connected to a crank which is connected to the connecting rod which carries the spreaders.
    Type: Grant
    Filed: September 29, 1988
    Date of Patent: December 4, 1990
    Assignee: Pfaff Industriemaschinen GmbH
    Inventors: Gerhard Eberhahn, Ludwig Franz
  • Patent number: 4968018
    Abstract: The invention relates to a device for separating, delivering, and depositing material blanks, for use in the textile industry or the like which improves heat transfer to the gripping surface in a device in which the heating device is arranged in such a way that it is protected from external forces. The device comprises a heatable gripping plate, which has a gripping surface and an expansion chamber adjacent thereto, in which a refrigerant is able to expand and thus cool the gripping plate to below the freezing point so that a material blank will freeze onto said gripping surface.
    Type: Grant
    Filed: October 18, 1989
    Date of Patent: November 6, 1990
    Assignee: Pfaff Industriemaschinen GmbH
    Inventors: Klaus Hoehne, Bernhard Mertel, Erich Willenbacher
  • Patent number: 4955307
    Abstract: A device for use with sewing machines for transport of work pieces. The transport device removes finished workpieces from a sewing area and feeds the workpieces to a transfer point at which the end section of the work piece is held with little force to allow the workpiece to be gripped by a stacking element. The arrangement allows for the next workpiece to be inserted into the sewing area simultaneous with the removal of the finished workpiece. The transport device includes a swivelable arm carrying a driven conveyor belt. The arm may be swivelled upward once the front section of the work piece has been moved underneath the swivelling axis of the arm, so that a new workpiece can be inserted. The conveyor belt can be arrested before the end section of the workpiece passes through. The conveyor belt contact pressure can be reduced such that the work piece can be pulled out easily by a stacker.
    Type: Grant
    Filed: June 2, 1989
    Date of Patent: September 11, 1990
    Assignee: Pfaff Industriemaschinen GmbH
    Inventors: Wolfgang Kolb, Ernst Albrecht