Abstract: In threading an eyelet of a looper of a sewing machine, a slide member is displaced until a positioning portion of the slide member comes into contact with the looper. In this contact condition, a thread pushing projection for pushing a looper thread is displaced to penetrate into the eyelet of the looper so that the looper thread pushed by the thread pushing projection passes through the eyelet of the looper. The looper thread having passed through the eyelet is grasped by a grasping portion of the slide member. Thereafter, the thread pushing projection is retracted from the eyelet of the looper, and the slide member is returned to an original position, thus completing the threading operation.

Abstract: An overlock sewing machine having a loop spreading member which provides a retracted position and an operative position. In the retracted position, the loop spreading member is moved away from one side of needle hole slots, which one side being positioned farther from an edgeline of a workpiece. In the operative position the loop spreading member is engageable with a chain and the chain is insertable over the outer tongue upon shifting of the chain portion located at its needle side toward a workpiece feed-in side. The sewing machine further includes drive means connected to the loop spreading member for moving the loop spreading member from its retracted position to the operative position prior to a shifting operation of the chain toward the workpiece feed-in side with respect to positions of the needles.

Abstract: A threading device for threading a lower looper of an overlock sewing machine, an orifice and a slot are formed in an arm of the lower looper, a hook if formed on a rear end of the arm and obliqued from the arm at a sharp angle, a holder is formed on one end of a lever, a thread threaded through the orifice of the arm can be carried by the holder toward the rear end of the arm, the thread will slip over the hook and located behind the hook when the holder moves beyond the hook, and the thread can be hooked by the hook and received in the slot of the arm when the lever is released.

Abstract: The driving mechanism comprises a driving arm (10) fastened to a drive shaft (9) operated with an oscillatory movement about its own axis. Pivoted to the free end of the driving arm (10) is a support arm (11) carrying an upper looper (4). The support arm is also fastened to an auxiliary arm (12) pivotally mounted to a bearing pin (13). The bearing pin is eccentrically fixed to an auxiliary pivot pin (15) housed in the machine bed (2), with possibility of rotation about an axis which is offset relative to the axis of the support pin. The auxiliary pin (15) can be selectively oriented about its own axis according to different angular positions for the purpose of modifying the position of the axis of the bearing pin (13) and, as a result, the path taken by the upper looper (4).

Abstract: A thread chain guiding device provides a needle-thread-guide plate which extends underneath a throat plate by energizing a solenoid as needed. Thus, the needle-thread-guide plate pushes the needle threads twined around a lower looper outwardly away such that the thread chain is prevented from hanging on an inner chain-off finger when it is rotated counter clockwise. The needle-thread-guide plate is retracted during a normal stitching process by de-energizing the solenoid.

Abstract: This invention provides an overlock sewing machine with a threading mechanism that is both easier and more efficient to use. As shown in FIGS. 1 and 7, the overlock sewing machine has a vertically movable needle (6, 106), a looper carriage (18, 118) connected to a rotating shaft, and a looper (11, 111) on the end of the looper carriage. The looper extends laterally over the looper carriage and has a thread-receiving eye (11a, 111a). The looper and the needle cooperate to form a chain stitch. As shown in FIGS. 3 and 9, a thread-guiding member (25, 125) next to the looper pivots with the looper to guide a thread LT through the thread-receiving eye. A movable lever (30, 130) pivots with or relative to the looper. A thread-delivering member (39, 139) mounted on the movable lever that can be set in two positions: a first position corresponding to a first position of the thread-receiving eye, and a second position corresponding to the thread-guiding member.

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.

Abstract: A composite sewing machine has a lock stitch mechanism and an over-lock stitch mechanism. A switching mechanism is connected to the stitching mechanisms for switching the operation of the sewing machine between a lock stitch operation and an over-lock stitch operation. The machine has a single needle carrying element, a needle position converter for changing the position of the needle carrying element laterally of the stitching direction and including a needle bar connecting stud engaging the needle carrying element and a fulcrum shaft on which the stud is rotatably mounted for pivotal movement to change the vertical orientation of the needle carrying element between a lock stitch position and an over-lock stitch position which are adjacent to each other and juxtaposed laterally on the sewing machine.

Abstract: The present invention relates to a looper shifting device in an overlock sewing machine having an upper looper and a lower looper and capable of looping the end of the cloth by one needle with use of three threads composed of an upper thread (first thread) in a needle, a second thread in the upper looper, and a third thread in the lower looper. A tip end of a guide passage provided at the upper looper is open to a tip end rear portion of a brade of the upper looper and positioned adjacent to a pore. A horn is retractably inserted in the guide passage. A spreader is defined by the tip end of the horn protruded from the opening and tip end rear portion of the upper looper. There is provided at the side of the upper looper a holding device for holding the base portion of the horn.

Abstract: A cam shaft of a rotary looper thread take-up is extended short of a thread guide and thus provides a free space there-between. A thread introduced from the tip-end-side of the cam shaft is prevented from being entangled into the cam shaft when the looper thread becomes broken. In a preferred embodiment, three slit-like guides placed in parallel and two cams placed there-between are effective to introduce the looper thread into the rotary looper thread take-up by a simple operation without requiring an operator to visually align the thread to pass through an eyelet.

Abstract: An overcasting attachment for use with a sewing machine includes a cross thread guide lever driving mechanism for transmitting the movement of a needle bar interlocking mechanism operatively connected to a needle bar of the sewing machine to an upper cross thread guide lever and a lower cross thread guide lever supported by a base plate. The cross thread guide lever driving mechanism operates to synchronize the movement of the lower cross thread guide lever toward a position of engagement with a bobbin thread and the engagement of a lower cross thread with the upper cross thread guide lever.

Abstract: Apparatus and method for severing the needle and looper threads of a chain stitch formed by a sewing machine having an in-line looper system. The sewing machine has a needle plate and a needle carrying the needle thread through the material and the needle plate to form a needle loop of needle thread therebelow that has a needle side running to the needle. The apparatus comprises a stationary knife, a spring positioned below the stationary knife and biased in a direction toward the stationary knife, and a movable knife slidably mounted between the stationary knife and the spring which yieldingly urges the movable knife thereagainst. The movable knife has one penetrating end with a pair of axially offset barbs, a lagging barb and a leading barb closer to the penetrating end of the movable knife than the lagging barb. These three elements cooperate to hook and sever the needle side of the needle loop and the looper thread below the needle plate and prepare the looper thread for the next stitch.

Abstract: A sewing machine for forming stitches in a substrate, for example, in forming stitches in tissue during surgery, comprises a needle for passing thread into the substrate from one side thereof at a first location and for withdrawing the thread from the substrate at a second location spaced from the first location. The needle is removably operable solely from the said one side of the substrate. A stapling machine is also disclosed operating on similar principles for similar purposes.

Abstract: A triple-thread stitch is intended for sewing webs of netting over their edges, wherein one thread (2) forms straight loops (3) and two other threads (4 and 6) form turned loops (5 and 7). In the method of producing this triple-thread stitch, performed in a machine wherein the loop-forming members are the sewing needle (8), looper needle (9) and looper hook (10), the thread (6) of the looper hook (10) is formed into a turned loop (7) which is moved about the needle (8) until the latter's thread (4) forms a turned loop (5), and driven through the straight loop (3) of the thread (2) of the looper needle (9). In the machine for sewing netting webs over their edges with a triple-thread chain stitch, the looper hook (10) is mounted for moving about the needle (8) at the side of the device (17) for advancing the webs, which provides for forming from the thread ( 4) of the needle (8) a turned loop (5) when the looper hook (10) moves the turned loop (7) intermediate the needle (8) and its thread (4).

Abstract: A looper changeover device for a sewing maching capable of making overlocked stitches is improved by having a manually operable, rotatable selector mechanism for securing and selectively positioning a looper with respect to a looper holder and a looper driving mechanism between a first position and a second position wherein the looper can be moved along separate paths for the selective production of overlocked stitches with one needle and three threads or one needle and two threads. The rotatable selector mechanism can include a rotatable disk or dial supported by the holder and engaging a portion of the looper for positioning and securing the looper in either of the first and second positions.

Abstract: A looper for a sewing machine capable of making overlocked stitches has a unitary distal portion which is operable for the selective production of overlocked stitches with one needle and three threads or one needle and two threads. The unitary distal portion of the looper includes an upper looper portion and a spreader portion. A holder is provided in connection with driving means for supporting the looper, and a positioning arrangement is provided to selectively position the unitary distal portion of the looper in a first position for movement along a first path or in a second position for movement along a second path for the selective production of the stitches.

Abstract: A triple thread chain stitch machine for sewing netting. A knee shaped needle (1) is mounted on a reciprocating bar (2). A stud on the needle is received by the bar (12) for rotation about the stud. A lug (19) on the needle cooperates with a catch (22) to limit needle rotation.

Abstract: A looper drive for a chainstitch sewing machine comprising a rigid guide stud which is part of a support member for a looper shaft. The rigid guide stud is surrounded by a bushing which is swivably mounted on the guide stud. The guide stud as well as the bushing are provided with openings through which the looper shaft extends.

Abstract: A hook drive for chain stitch sewing machines, in particular for those suited to be hand-held, which comprises an upper hook and a lower hook of curvilinear configuration having a hook holding shank supported obliquely in a box-like case. Each hook is connected to a drive including a gear whereto one end of a swinging yoke is articulated eccentrically which has the opposite end pivoted centrally to a block made rigid with a respective one of said shanks. The two driving gears, one of which is connected to a drive shaft, are in meshing engagement with each other and with a third gear which may drive a movable cutter blade.

Abstract: A looper drive for a chain stitch sewing machine, in which the joint between a connecting rod driven by a main shaft and a lever seated on a swivel shaft is a sliding and swiveling joint. Upon rotation of a ball eccentric, the transverse component of the rotary motion of a spherical shell is enabled by a rod sliding in bearing eyes on a bifurcated lever and the swinging motion of the lever, caused by the longitudinal component of the rotary motion of the spherical shell is enabled by the rod turning in the bearing eyes.

Abstract: A thread cutting device for a cylinder bed sewing machine for sewing by means of a plurality of needles a piece of fabric supported on a cylindrical bed while transporting the fabric piece in a given direction, wherein a hook portion of a thread catch member which is adapted to plunge into and retreat from needle thread loops in orthogonal relation to an obliquely inclined plane of opening of the needle thread loops so that a plurality of needle and looper threads are accurately caught into the hook portion and then carried along thereby for cutting. In addition, an arrangement is disclosed which enables the mounting of the thread cutting device without interferring with the movement of a looper, even if the available space within the bed is very limited.

Abstract: A looper assembly for a two thread bag closing sewing machine in a simple arc within a single plane on one side of a moving needle, the plane being parallel to the needle axis and intersecting the line of movement of the bags at an angle of less than 45 degrees to reduce thread wear and breakage. A process of stitching the bags utilizing looper movement within a single plane is also disclosed.

Abstract: In an actuating mechanism for the hook of portable sewing machines, a hook actuating profiled cam is provided which has a pin for simultaneously actuating the hook and the material transport feed dog through an interposed linkage having an adjustable element. By providing the hook formed with an eye, a double chain stitch seam can be effected. By further providing the cam with a depression for accommodating a foot of the hook therein during an oscillation of the foot, a greatly reduced overall size becomes achievable. Thanks to the adjustable element it also becomes possible to change the stitch length.

Abstract: Looper for sewing machines provided with a mounting shank having a positioning flat adapted to be coupled to a coacting flat formed on a positioner member, which positioner member can be angularly fastened on a looper support so that the coupling between the looper and the positioner takes place in a predetermined angular position in one and the same hole of the looper support.

Abstract: A looper throw out mechanism is provided for bodily moving sewing machine loopers from their normal operative position to a servicable position and back. The looper throw out mechanism includes a looper carrier pivotally arranged on the looper drive shaft, a fork like member attached to the looper carrier, a control disc disposed in operative combination with the fork like member for defining the angular displacement limits of the looper carrier, and a manually operated locking device for releasably securing the looper carrier to the looper drive shaft. When looper servicing is desired, the locking device is released by the operator permitting the looper carrier and the loopers to be pivoted to a serviceable position removed from their operative position.

Abstract: A sewing device for use in multi-needle sewing machine comprising a plurality of needles, presser feet, throat plates, feed dogs and loopers arranged in parallel with each other, and optionally a plurality of spreaders arranged in parallel with each other. Each needle holder on which each needle is set is supported on a needle bed in a manner slidable in the direction of the row of needles and is fixed to any slided position by tightening each set screw. Each interval between needles are changed by changing the fixing position of each needle holder. Each presser foot, throat plate, feed dog, looper and spreader are respectively held by the presser foot holder, throat plate holder, feed dog holder, looper holder and spreader holder in a slidable manner along the direction parallel with the row of needles, and are fixed to the required positions corresponding to each of changed needle interval.

Abstract: An overlock machine is designed for easy placement of a thread through a looper. The members which would obstruct access to the looper are mounted on a movable portion of a bed frame. By swinging open the movable portion, the obstructing members are moved to their inoperative position. A fixed knife only, or both the fixed knife and the movable knife are mounted on the movable portion.

Abstract: A double chain stitch sewing machine having a feeding device with a feed dog oscillatingly movable in and opposite to the feeding direction for producing a relative movement between a workpiece and the sewing machine. It has a needle reciprocatingly driven by a crank mechanism, at which the feeding mechanism also imparts synchronous jogging movements to the needle in order to generate a needle feed movement. The reciprocatingly and joggingly driven needle cooperates with a looper oscillatingly driven by a looper drive mechanism in parallel with the feeding direction. The looper drive mechanism is formed as a six-bar-linkage-mechanism provided at the input with a stationary pivot and at the output with a stationary pivot and provided with an intermediate pivot.

Abstract: A device for controlling the looper thread of a double chainstitch sewing machine has a looper which can be oscillatingly driven in the sewing direction. A link mechanism is provided to drive the spreader, said link mechanism being designed as a six-bar linkage mechanism with a four-bar linkage and a secondary two-link group. The basic linkage and the two-link group are arranged in such a manner that two links are guided during a movement of the spreader in an extreme position in which it does not spread the looper thread. Thus a spreader movement is produced which is particularly adapted to the sewing process.

Abstract: A chainstitch machine has an edge trimmer knife driven in vertical chopping motion adjacent the needle by a linkage actuated by an oscillating shaft that operates synchronously relative to stitch-forming components. The linkage includes a bracket oscillated by the shaft and a joint movable along the bracket between a first position, in which the axis of the joint is offset from the axis of the shaft to communicate oscillating movement to the knife, and a second position, in which the axis of the joint is concentric with the shaft and transmits no oscillatory movement. In the second position, the knife is retracted by the linkage to a location above the region through which work pieces move, but in the first position, the linkage moves the knife down so that part of the knife extends through the plane of the throat plate and is pressed against an edge of a throat plate insert by a small pressure slide entirely within a notch in the insert and guided by juxtaposed edges of the notch.

Abstract: A looper operating device for sewing machines in which the looper is provided with forward movement and the machine's needle possesses work feeding movement which is synchronized and caused to perform its intended function simultaneously with the machine's feed dog. The device includes a lever member having an upper fulcrum to which actuating linkage for the looper are connected. The opposite end of the lever member includes a lower fulcrum 25 connected to a lever element mounted on a shaft that is operatively connected to and simultaneously actuates both the feed dog and needle. This lever element is stationary when the stitch length is zero or is oscillating with an amplitude proportional to the stitch length.

Abstract: Multiple hem stitches are produced for joining a plurality of superimposed fabric materials along their edges by employing a sewing machine having a pair of vertically reciprocating needles each carrying a needle thread and a pair of loopers each carrying a looper thread. The first and second needle threads extend along the fabric edge and in parallel with each other on the upper face of the fabrics and penetrate through the fabrics to form a first and second needle thread loops on the underside of the fabrics. The first needle thread loop is distended laterally to the fabric edge by the first looper. The first looper thread encompasses the first needle thread at each penetration point and extends laterally on the upper face of the fabrics to form a first looper thread loop which is caught by the descending first needle to be interlocked with the first needle thread loop along the fabric edge.

Abstract: An anti-wobble device for a connecting rod (3) in a mechanism comprising a crankshaft (1) connected via a spherical coupling (4) to the larger end (5) of the said connecting rod (3), the smaller end (6) of which is connected via a similar spherical coupling (7) to an arm (8) fixed to a driven shaft (9), the axis of which is perpendicular to the axis of the crankshaft (1), in which device, a rigid element (13-16) is integrally and perpendicularly mounted on the driven shaft (9), with respect to which it can also be adjusted both axially and radially; this rigid element makes contact with a curved surface (12) formed on the small end (6) of the connecting rod (3) and concentric with respect to the axis of the said small end (6) of the connecting rod (3), against which surface the said element can rub in a parallel manner during the movements of the mechanism.

Abstract: An improved device for changing the trajectory of the upper looper in an overlocking stitching machine in which the looper carrying rod slides in a cylindrical element contained within a support body having support means located at different distances from the rocking axis of the cylindrical element so that the position of support body can be reversed to change the path of the looper trajectory.

Abstract: A hand operated sewing machine with opposing loop seizing points for forming chain stitches. A work feeding plate reciprocates with a plate member about a pivot. A flexible upstanding portion at one end of an arm is biassed by the moving plate member causing the other arm end to bias a cam affixed to the loop seizing points. This bias determines the cam path taken by a drive pin that provides motion to the loop seizing points.

Abstract: A force transfer assembly connects the output centerpoint of a Cardan gear mechanism to a work performing assembly. The motion of the output centerpoint moving in a first and second plane is translated by the force transfer assembly such that the work performing assembly moves in first, second and third planes. The force transfer assembly preferably includes a rotatable spherical element carried by the output lever of the Cardan gear mechanism, with a slider pin journalled in the spherical element and connected to the work performing assembly.

Abstract: A hand operable chain stitch sewing machine including a pivoted cam and looper assembly with a limited axial position has the looper mounted on the cam so as to deflect axially away from the cam when engaged by the needle of the machine and leave the cam in its limited position wherein cam tracks and a gate therefor are disposed for cooperation with an actuator for the pivoted assembly and a gate spring respectively.

Abstract: A sewing machine wherein the various stitch performing instrumentalities are driven by Cardan gear means. Particular sewing part mechanisms are associated with each of said Cardan gear means to produce the desired stitch. Both said sewing part mechanisms and said Cardan gear means being removable, and interchangeable within the frame of the sewing machine.

Abstract: A chain stitch sewing machine including a looper and cam assembly with cam tracks engageable by an actuator, a gate pivotally mounted on the assembly and a spring with one free end to engage and move the gate into positions controlling actuator movement between the tracks is provided with camming surfaces on a fixed member for lifting the free end of the spring to the top of the gate for passage from one side to the other.

Abstract: A chain stitch sewing machine including a double pointed looper is provided with feeding mechanism in which looper motion is used in conjunction with needle motion to control the movement of work under the needle of the machine.

Abstract: A pivotally movable cam having a double pointed looper thereon for seizing thread loops on one side of a sewing needle is formed with raised surfaces to engage the thread on the opposite side of the needle and thereby position the thread loops for looper point seizure.

Abstract: An actuating mechanism for a double pointed looper wherein the vertical reciprocating motion of a drive pin is converted into a controlled back and forth pivoting motion of the looper in a single thread chain stitch sewing machine.

Abstract: A sewing machine is provided with a double pointed looper and actuating mechanism therefore including a double tracked cam, an actuator operable on the cam tracks, and a gate with a resiliently movable portion for controlling movement of the actuator between the cam tracks.

Abstract: The output centerpoint of a Cardan gear mechanism is connected via a ball and a pin slideable therethrough to a lever which in turn carries a looper. Because the major axis of the lever and the axis swept out by the output centerpoint are skewed the lever is reciprocated back and forth along its own major axis while being rotated therearound. This results in the looper being swept back and forth along part of a generally helical-like path.

Abstract: A Cardan gear assembly having an output centerpoint means which moves along an elliptical path. A force transfer means connects the output centerpoint to a means operative to carry a work performing means. The major axis swept out by the means operative being skewed with respect to the major axis of the ellipse which is swept out by the output centerpoint. As a result, the work performing means will be swept along a curve which is of a portion of a helix as well as part elliptical. This curve takes the form of a partial helix wherein the outgoing path is different from the return path.

Abstract: A loop catching device for a sewing machine includes a rotatable loop taker carrying a lower thread, a pulse motor operated in a timed relationship with a reciprocating movement of a needle, and a looper arranged adjacently to the loop taker and driven by the motor. The loop taker and the looper are synchronized with the movement of the needle to catch the loop produced by the needle and hold the loop for a predetermined time.

Abstract: The present invention relates to an improved thread control mechanism for chain-stitch sewing machines. The present invention is adapted to apply a quick and effective clamping action to the sewing thread of the machine in timed relation with the rotary or oscillatory movements of the stitch forming instrumentalities. The mechanism's clamping force magnitude may be selectively regulated to exceed the tensile strength of the particular thread being used and is effective to break the thread should it become wound about an operable rotary shaft of the machine. The present invention includes a rotary actuating member for moving a thread engaging member between two extreme positions so as to entrap and intermittently clamp the thread at a location interposed between the stitch forming instrumentalities and the thread supply source.

Abstract: An actuating mechanism is proposed for the hook and feed dog in a portable sewing machine of the type employed for sewing bags of jute, paper, and the like. In the proposed mechanism, a single cam determines both the compound movement of the hook, which is spring loaded against the cam and provided with at least one ball for reducing the frictional resistance, and of the feed dog by means of a connecting rod journalled at one end to a vertically adjustable support such as to allow the length of the seam stitch to be varied.

Abstract: A device for forming double chain stitches in a sewing machine having independent thread sources for its needle and looper. The device includes a driving apparatus for causing travel of the looper solely in a rectilinear pathway in front of the needle and is effective in taking a loop of thread from the needle and to form a triangle of threads into which the needle will descend to effect completion of a stitch as the looper returns to its starting position.

Abstract: The tip end of the upper looper of an edge stitching sewing machine is adapted to have a different profile by engagement with a pawled looper arm provided on the upper looper itself or on a mounting post of the upper looper. When the pawled looper arm is engaged with the upper looper, the sewing machine performs one-needle two-thread edge stitching, while it performs its original one-needle three-thread edge stitching when the pawled looper arm is detached from the upper looper in a disengaged position.