Abstract: A needle bar 4 is supported by a needle bar supporter in a manner freely movable up and down relative to a frame. A crank 2 is fixed to an upper shaft 1, rotates with the upper shaft 1, and an output end thereof moves circularly. A crank rod 3 is connected to the crank 2 in a freely rotatable manner. A connection rod 8 is connected to an intermediate portion of the crank rod 3 in a freely rotatable manner, and is connected to the needle bar 4 in a freely rotatable manner. A length of the needle bar 4 and a length from a connecting position of the connection rod 8 and the crank rod 3 to a slider 7 differ. When the crank 2 circularly moves, the connecting position of the connection rod 8 and the crank rod 3 draws a trajectory of an ellipse.

Abstract: A needle bar 4 is supported by a needle bar supporter in a manner freely movable up and down relative to a frame. A crank 2 is fixed to an upper shaft 1, rotates with the upper shaft 1, and an output end thereof moves circularly. A crank rod 3 is connected to the crank 2 in a freely rotatable manner. A connection rod 8 is connected to an intermediate portion of the crank rod 3 in a freely rotatable manner, and is connected to the needle bar 4 in a freely rotatable manner. A length of the needle bar 4 and a length from a connecting position of the connection rod 8 and the crank rod 3 to a slider 7 differ. When the crank 2 circularly moves, the connecting position of the connection rod 8 and the crank rod 3 draws a trajectory of an ellipse.

Abstract: A sewing machine moves a needle up and down relative to a cloth based on drive force from a rotating upper shaft to form a stitch. A first output generating unit reciprocates a first output point along an output axis so as to convert the rotational motion of the upper shaft into a linear motion. An assist rod that serves as a connection portion links the first output point with a needle bar. A needle-bar swing unit swings the needle bar. An output shaft moving unit moves a guide that is the output axis in a cloth feeding direction in accordance with the motion of the needle-bar swing unit. The assist rod changes the inclination in accordance with the movement of the output axis, and reciprocates the needle bar in substantially parallel with the output axis while maintaining the inclination.

Abstract: A sewing machine moves a needle up and down relative to a cloth based on drive force from a rotating upper shaft to form a stitch. A first output generating unit reciprocates a first output point along an output axis so as to convert the rotational motion of the upper shaft into a linear motion. An assist rod that serves as a connection portion links the first output point with a needle bar. A needle-bar swing unit swings the needle bar. An output shaft moving unit moves a guide that is the output axis in a cloth feeding direction in accordance with the motion of the needle-bar swing unit. The assist rod changes the inclination in accordance with the movement of the output axis, and reciprocates the needle bar in substantially parallel with the output axis while maintaining the inclination.

Abstract: Embroidery sewing machine having a Y-direction drive mechanism including an elongated arm which is normally accommodated in a cutout portion formed at a bed of the machine body and forms a part of that body. The upper side of the arm is continuous with the upper side of the bed in a same plane. The arm has a frame support to which an embroidery frame is removably attached, the frame holding a work to be embroidered. The arm is arranged as turnable to extend from the rear side of the bed into the depth direction (Y-direction) of the machine, where the arm is operative for embroidery stitching. The arm is connected to an X-direction drive mechanism arranged in the machine body and may be moved in the width direction (X-direction) of the machine body, by the X-direction drive mechanism while the embroidery frame is moved in the Y-direction along the arm.

Abstract: An embroidery sewing machine is described. The sewing machine has a Y-direction drive mechanism including an elongated arm 1 which is normally accommodated in a cutout portion 3 formed at a bed 90 of the machine body and forms a part of the machine body, wherein the upper side 10 of the elongated arm 1 is continuous with the upper side 91 of the bed 90 in a same plane. The elongated arm 1 has a frame support piece 19 to which an embroidery frame is removably attached, the embroidery frame holding a work to be embroidered. Further the elongated arm 1 is arranged as being turnable to extend from the rear side 93 of the bed 90 into the depth direction of the sewing machine, that is, in the Y direction where the elongated arm 1 is operative for embroidery stitching.

Abstract: 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.

Abstract: An opening plate which closes a lower thread bobbin is provided with a drawing of a bobbin on its surface. A bobbin drawing is exactly overlapped with the bobbin when the plate is completely closed. Also a drawing of a thread tension adjusting device in a required position and a drawing of a lower thread normal path are provided on the opening plate. The drawings indicate to a machine operator the position of lower thread holding bobbin correctly inserted in a horizontal full rotation loop taker device and the path of drawing of the lower thread therefrom so as to enable the operator to insert the lower thread holding bobbin in the horizontal full rotation loop taker device correctly in place, and pass the lower thread wound on the bobbin through the thread tension adjusting device correctly.

Abstract: A device for synchronizing feeds of a lower and upper fabric in a sewing machine, which device comprises a control cam, a presser bar, a turning plate with a movable presser thereon, a switching plate movable on the presser bar and connected to the control cam which moves the switching plate, and a control plate interconnected between the control cam and the movable presser and rotated to move the switching plate and thus the movable presser so that it may be pressed against the fabric being sewn.

Abstract: A lifting mechanism for a floppy disc device and including a base, a carrier pivotally mounted to the base, a collet arm pivotally mounted to the carrier and having an end biased in a clockwise direction, a collet attached to the collet arm, a pad arm having an end biased in a counterclockwise direction and a pad, the pad arm engaging under pressure the collet arm, a head carriage pivotally receiving the pad arm, and components for vertically moving the collect arm engaging the pad arm in synchronism with vertical movement of the carrier.

Abstract: A sewing machine produces patterns of stitches including straight stitches, in which a single operating dial is manually operated to select one of the patterns with a proper feeding amount in one rotation range thereof, and to vary feeding movement with a specific cycle in relation to the same patterns in another rotation range thereof to produce so called "super patterns".

Abstract: A needle threading device for sewing machines includes a thread guide which is pivotably mounted on a mounting plate parallel to the needle bar; a projection at the end of the thread guide is displaceable against the needle, and a thread inserting element operated by a pushbutton is slidably mounted for alignment with the thread guide to push the thread through the needle eye.