Abstract: A sewing machine having a drive shaft rotated by a machine motor to vertically reciprocate a needle carrying an upper thread is provided with a device for adjusting the tension of a lower thread pulled out from a bobbin located in a bobbin carrier of the sewing machine. The device includes a tension lever cooperated with a spring element, and a releasing lever which is in engagement with a cam rotated by the drive shaft. The position of the tension lever relative to the lower thread is effected by a manually operated dial and a cam engageable with the spring element. The releasing lever is adapted to intermittently release the tension lever from the lower thread during the stitching operation.

Abstract: A device for adjusting the thread tension of multi-needle automatic embroidery machines in which each needle or thread lever has associated with it a thread brake having two brake disks between which there extends a thread which is guided over the thread lever to the needle. One of the brake disks which are pressed against each other by a spring is displaceable relative to the other brake disk in order to change the thread tension. To set the thread tension for all the needles embroidering and at the same time for those needles which are disconnected to zero or a maximum value, the displaceable brake disk (11) of each thread brake is mounted on a bolt (13) which is displaceable relative to both brake disks (10, 11). The bolt is provided with an abutment (13c) for carrying along the displaceable brake disk (11). Each bolt (13) of each of the thread brakes is displaceable by one of several cams (15) which are arranged jointly on a camshaft (16).

Abstract: In a sewing machine having an upper presser (6), a work feed (8) disposed below and aligned with the upper presser (6), and a work support (9) about the feed mechanism (8), the feed mechanism (8) and the work support (9) are movable in unison to a raised position adjacent the upper presser and into a lowered position in which the feed mechanism is spaced further from the upper presser, the feed mechanism and the work support being resiliently loaded upwardly. In another aspect, a drive for a thread take-up element includes a rotary axially-acting cam (15,23), and a cam follower (24) coupled to the thread take-up element (25,29).

Abstract: A thread-tension regulating device for multi-thread sewing machines comprises a speed change mechanism and a thread-tension regulating mechanism. The speed change mechanism has an infinite speed variator and pulleys for operating the variator. The thread-tension regulating mechanism comprises a cam shaft rotated by the speed change mechanism, cams fixed onto the cam shaft, operating rods reciprocated by the cams, pairs of tension discs mounted on the corresponding operating rods, and biasing elements for periodically imparting tension to threads which pass between the paired tension discs according to the reciprocating movement of the operating rods. By selecting the shape, dimension and angular phase differences of the cams, a biasing force between the paired tension discs, and the rotational speed of the cam shaft as given by the speed change mechanism, a variety of patterns can be formed on cloth by the multi-thread sewing machine.

Abstract: A thread handling system for a sewing machine is provided with a tensioning device without a check spring, a thread takeup member for pulling thread from the tensioning device and setting stitches, and a thread holder including a pair of elongated members which grasp and meter thread to a needle and looptaker. The tensioning device is disposed with respect to the operating limits of the takeup member to enable thread to be withdrawn from the tensioning device without being pulled from the thread source and with only slight thread tension.

Abstract: A sewing machine attachment and method for use in connection with multiple thread sewing machines to provide selective control of decorative stitch formation to selectively vary either pattern amplitude, or frequency of pattern repeat or both. A selectively adjustable variable speed drive is employed to drive a cam shaft carrying a plurality of selectively adjustable cams one for each thread forming the pattern which cams bear against a plunger acting to control the position of the selectively adjustable pressure plates forming the thread tensioners through which the threads of the machine are guided. By varying either speed and/or cam position and/or thread tensioner plate pressure different stitch formation can be obtained.

Abstract: A sewing machine thread snubber having a fixed part and having a movable part pivoted thereon is provided with mechanism operable by needle bar reciprocating mechanism for moving the pivoted part of the snubber between a needle thread releasing position and a position wherein a drag is imposed on the thread.

Abstract: A thread snubbing device for a sewing machine is provided with a cage which attaches to a needle clamp, and with a shoe of predetermined mass which is loosely confined by the cage wherein it is caused by inertia and engagement with the cage to be moved against a length of needle thread between the shoe and clamp to apply a snubbing action thereto during loop seizure and loop formation.

Abstract: A sewing machine is provided with an actuator controlled thread take-up lever. A microprocessor is programmed to provide signals for controlling the actuator to provide a system wherein the interaction of the needle, the needle thread take-up and needle thread tension are optimally controlled. A thread metering mechanism, also under microprocessor control, is included in the system.

Abstract: A tufting machine wherein the needle bar is reciprocated by a number of like, mounting assemblies which are positioned along the length of the machine, with each assembly comprising a number of linkage arms which are pivotally interconnected to thereby minimize friction and power consumption. Also, the reciprocation of the needle bar, which is guided by the assemblies, results in a pause at the bottom of the needle movement to facilitate pick-up of the yarn loops by the loopers, and the needles have a component of movement in the direction of movement of the backing fabric at the bottom of their stroke, whereby the needles function to deposit the yarn loops on fixedly mounted loopers. The machine further includes a yarn tension control arrangement which is readily adjustable during operation of the machine.

Abstract: When weaving, movable and stationary discs grasp or grip intermittently the weft yarn therebetween. One of the discs has at its contacting surface a circular recess encircled by a bank. The ridge of the bank contacting the flat surface of the other disc does the gripping.

Abstract: So-called raised buttonholes are sewn on a double-lock-stitch sewing machine with the fabric workpiece turned face down on the stitchplate of the sewing machine and the upper-thread tension being such that the interlocking loops of the upper and lower threads lie upon the downwardly facing side of the workpiece. According to the invention, the upper-thread tension at the end of a buttonhole-stitching cycle for the fastening stitch is increased above the lower-thread tension temporarily so that the interlocking loops of the upper and lower threads during this last fastening stitch lie within the thickness of the material or on the upper face of the downwardly turned workpiece.