摘要:
A thread connecting device for a sewing machine cuts an upper thread which is extending between the sewing machine and one of a plurality of thread spools, and connects an end of a thread belonging to the sewing machine and an end of a thread belonging to the thread spool, in such a manner that the connected part of the threads can smoothly pass through a needle eye, whereby it is possible to supply a desired color thread with respect to the sewing machine having a single needle bar. Therefore the applicable scope of the pattern stitching may be largely widened for colored clothes or other fabrics, especially an embroidery stitching may be performed which requires many kinds of color threads.
摘要:
A sewing machine with a vertically reciprocable and laterally swingable needle for sewing provided with an upper thread includes a rotatable loop taker for catching a thread loop during synchronous rotation thereof with the needle, and is rotatable in a horizontal plane with respect to the needle. A bobbin member is mounted within the loop taker and carries a lower thread forforming a lock stitch with the lower thread when the loop taker catches a thread loop. A feed dog member includes a plurality of feed dog elements for synchronously moving vertically and horizontally with the needle so as to allow the fabric to be moved relative to the needle. A thread guide is disposed adjacent a certain one of the plurality of feed dog elements for guiding the lower thread to a predetermined side of the swinging needle each time the feed dog member is vertically moved.
摘要:
A sewing machine having lock stitching device incorporated in a frame and driven by a primary driving member comprising a detachable overlock stitching device having its own needle bar driving mechanism spaced apart from the stitch forming part of the lock stitching device and driven by the same primary driving means. Preferably, a switching mechanism provides for the actuation of one stitching device while the other is at rest.
摘要:
A sewing machine comprises a thread deflecting device arranged between a thread take-up lever and a needle and which in response to a swinging movement of a needle bar effected in response to selection of a zigzag stitch, deflects the upper thread laterally of a fabric feeding direction. A thread blocking device is provided on one side of the thread deflecting device. The sewing machine further comprises an actuator operated in response to actuation of a zigzag stitch pattern selecting key to move the thread blocking device to an operative position thereof. The thread blocking device in the operative position blocks the upper thread as it is deflected in one direction by the thread deflecting device to give a predetermined degree of tension to the upper thread, so that the stitch is tightened on one side of the zigzag stitch in addition to the tightening of the stitch by a thread take-up lever.
摘要:
When a lower thread is effected with tension by an upper thread, a lower thread tension device is actuated in a certain working distance with very small resistance to an extent that a lower thread is drawn as if without resistance. If the lower thread is effected with said tension outside of said distance, it is not drawn out with large resistance. An actuation means successively receives information about thread consumed in each of the stitches and information about rotation phase of the sewing machine from a phase sensor. In the distance of a strong resistance, the lower thread is prohibited from drawing, and the thread is tightened in this distance.
摘要:
A thread tightening device for a sewing machine of the type having a main shaft, a vertically reciprocable needle bar with a needle carrying an upper thread, a loop taker and a drive shaft for driving the loop taker and a feed dog, the thread tightening device includes a group of pattern cams operatively connected to the main shaft, pattern selecting device and an arrangement for controlling the vertical movement of the feed dog. This arrangement comprises a control cam and a rotatable shaft, the control cam being slidably axially mounted on the rotatable shaft but not turnable with respect to the shaft. The thread tightening device also includes an element arranged for vertical reciprocating movement in a timed relation with the feed dog, which element engages a lower thread during the stitching operation of the sewing machine. A thread tension adjusting device is provided in the machine which comprises an adjusting cam operatively connected to the pattern cams and a linkage arrangement which is operatively connected to the adjusting cam and to the control cam to displace the control cam in the axial direction in response to a set position of the adjusting cam to thereby adjusting lower thread tension in accordance with the respective pattern cam.
摘要:
A sewing machine includes an automatic thread tension adjusting device comprising an upper thread tension member arranged in an a thread running path between an upper thread source and a main thread take-up lever. An auxiliary thread take-up lever is arranged in the upper thread running path between the main thread take-up lever and a needle holding the upper thread. A thread engaging part guides the upper thread. A thread presser is arranged laterally of the upper thread running path between the main and auxiliary thread take-up levers and normally clamps the upper thread. A detector detects a predetermined rotation phase of a drive shaft of the machine and thread elongation, respectively, and generates respective electric signals. A control circuit causes the thread presser to release the upper thread in response to the electric signals generated by the detector.
摘要:
This invention makes a proper calculation to an amount of supplying a lower thread to be required to forming of a stitch with stitching information in relation with changing of a needle dropping position from a preceding stitch to a present stitching, so that the lower thread is forcibly drawn out in accordance with said calculation, and makes a proper calculation to tension of an upper thread optimum to forming of a stitch with stitching information so as to determine the optimum upper thread tension in accordance with said calculation, or makes a calculation to the amount of supplying the upper thread optimum to forming of a stitch with stitching information so as to draw out the upper thread in accordance with said calculation.
摘要:
A thread tightening device for a sewing machine of the type having a main shaft, a vertically reciprocable needle bar with a needle carrying an upper thread, a loop taker and a drive shaft for driving the loop taker and a feed dog; the thread tightening device includes a group of pattern cams operatively connected to the main shaft, pattern selecting device and an arrangement for controlling the vertical movement of the feed dog. This arrangement comprises a control cam and a rotatable shaft, the control cam being slidably axially mounted on the rotatable shaft but not turnable with respect to the shaft. The thread tightening device also includes an element arranged for vertical reciprocating movement in a timed relation with the feed dog, which element engages a lower thread during the stitching operation of the sewing machine. A thread tension adjusting device is provided in the machine, which comprises an adjusting cam operatively connected to the pattern cams and a linkage arrangement which is operatively connected to the adjusting cam and to the control cam to displace the control cam in the axial direction in response to a set position of the adjusting cam to thereby adjusting lower thread tension in accordance with the respective pattern cam.
摘要:
A method of automatically controlling thread tension in a sewing machine according to which a first thread tension device is provided between an upper thread source and a thread take-up lever, and a second thread tension device is provided between the first tension device and the thread take-up lever. The first thread tension device is operated to apply a constant pressure to the upper thread such that the thread take-up lever is able to draw out the upper thread upon moving upward. The second thread tension device is operated to fixedly hold the upper thread until the thread take-up lever moves upward to an upper dead point thereof through a lower dead point thereof, at which the take-up lever moves downward to supply the upper thread to the needle. The second thread tension device is further operated to effect release of the upper thread when the thread take-up lever reaches the upper dead point thereof and until the thread take-up lever moves downward to a thread supply starting position thereof.