Abstract: A sewing machine moves a presser foot up and down through a presser-bar lifting lever to depress a cloth. The lever is moved down by a stepping motor at a constant move-down amount. A compression spring is present between the stepping motor and the presser foot. The compression spring is compressed by some of the constant move-down amount of the lever, and applies, to the presser foot, pushing force canceling repulsive force from the depressed cloth. The move-down amount of the presser foot is detected by an encoder, and a thickness of the cloth is calculated by a cloth-thickness calculator. The cloth-thickness calculator performs calculation based on the move-down amounts at two timings in a time period at which the presser foot depresses the cloth and attempts to further move down.

Abstract: The presser lifting mechanism of a sewing machine includes a cloth presser, a pressing rod which holds the cloth presser by a bottom end portion thereof, a rod holder which is fixed to the pressing rod, a pressing spring a bottom end portion of which is in contact with a top end portion of the rod holder and which pushes the cloth presser downward via the rod holder, a push-up member through which the pressing rod is inserted so as to be movable in the vertical direction and which is in contact with the rod holder from below and can pushed it up, a link body which is in contact with a bottom surface of the rod holder and is connected to the push-up member, and a presser motor which is linked to the link body and serves as a drive source for elevation and lowering of the cloth presser.

Abstract: A sewing machine includes a detection unit configured to detect a moving direction of an object when the object placed on a sewing machine bed is moved in any direction, a cutting needle having a distal end formed with a blade edge and configured to form a cut in the object, an up-down drive mechanism configured to reciprocate the needle in an up-down direction, a rotational drive mechanism configured to rotate the needle about a rotation axis line of the needle, and a control device configured to control the up-down drive mechanism and the rotational drive mechanism based on a result of detection by the detection unit so that an orientation of the blade edge is changed according to the moving direction of the object and the needle is reciprocated to form the cut in the object with the blade edge being in the changed orientation.

Abstract: A controller of a sewing machine configured to execute a pre-positioning operation including controlling a needle bar driving mechanism, based on a thickness of a workpiece cloth detected by a thickness detection mechanism and a vertical position of a needle bar detected by a needle bar position detection mechanism, to stop a needle bar at a preset position immediately before a tip of a sewing needle pierces the workpiece cloth, controlling a pressure adjustment mechanism to adjust a pressure of a presser foot at a predetermined pressure that allows movement of the workpiece cloth, and controlling a feed dog switching mechanism to switch a feed dog to an inoperative state.

Abstract: A controller of a sewing machine configured to execute a pre-positioning operation including controlling a needle bar driving mechanism, based on a thickness of a workpiece cloth detected by a thickness detection mechanism and a vertical position of a needle bar detected by a needle bar position detection mechanism, to stop a needle bar at a preset position immediately before a tip of a sewing needle pierces the workpiece cloth, controlling a pressure adjustment mechanism to adjust a pressure of a presser foot at a predetermined pressure that allows movement of the workpiece cloth, and controlling a feed dog switching mechanism to switch a feed dog to an inoperative state.

Abstract: A device for operating several sewing functions is provided with a single control disk with curved paths arranged peripherally and facially on the control disk for acting radially and axially. The control disk is driven by a stepper motor and allows individual or several functions to be executed during the rotary movement as well as temporarily stopping others.

Abstract: A needle bar stop device for a sewing machine in which a needle bar arm is separated into two parts, a first arm on a main shaft side, the rotation of which is controlled by a sub-shaft and a second arm on the needle bar side which is capable of rotating about the sub-shaft. An extended part is provided on either the first armor the second arm extending along the side surface of the other arm, and an insertion hole is formed in the extended part. An engaging hole is formed in the other arm so as to be capable of aligning with the insertion hole. A movable engaging member fitting in the insertion hole is part of a coupling mechanism that is selectively operated to cause the engaging member to engage with and disengage from the engaging hole.

Abstract: A speed controller for controlling revolution speed of the upper shaft of a cycle sewing machine comprises a first disk shaped stop lever adjustment cam that has a small diameter portion, middle diameter portions and a large diameter portion. The cam is rotatably driven by an upper shaft. The small diameter portion establishes a neutral position at which a first driving clutch for low speed rotation and a second driving clutch for high speed rotation are disengaged from each other. The middle portions establish a position at which the first clutch is connected to a first driving wheel for low speed rotation. The large diameter portion establishes a position at which the second clutch is connected to a second driving wheel for high speed rotation. A first end portion of the large diameter portion is defined by a second cam. The second cam is secured to the first cam by an adjustable device which can vary the circumferential position of the second cam.

Abstract: A control device for a cyclic sewing machine for controlling driving condition of a main shaft of a cyclically operated sewing machine. The control device includes a clutch mechanism provided between a driving source and a main shaft, a switching member for switching the clutch mechanism between a power cutoff condition, a low-speed drive condition and a high-speed drive condition, a control cam rotatable at a reduced speed in interlinked relation to the main shaft, and a lost-motion connecting means. When switch the sewing machine from the power cutoff condition to the low-speed condition, a lost-motion is produced between the operating member and the switching member. The control cam is rotated in response to rotation of the main shaft, the operating member and the switching member are moved in accordance with cam profile. The clutch mechanism and hence the main shaft are switched between the drive conditions based on the movement of the switching member.

Abstract: A stopping device for an eyelet button holing machine provides a stopper arm which plunges into a recess portion of a stopper cam positioned coaxial to the main shaft. To absorb the stopping impulse, extra wheel cams are provided coaxial to the main shaft which induce the stopper arm to be inclined such that its position causes a clutch pulley to contact with a low speed pulley and then the stopper arm plunges into the recess portion of the stopper cam. Thus, the machine is stopped in two steps and the stopping impulse force is effectively alleviated.

Abstract: A drive device for positioning a sewing machine main shaft and driven by a positioning motor into a needle-up position when it is stopped for example, after the thread is cut comprises a removable drive lever member which has a tappet portion which engages wtih the shoulder of a cam which is mounted on the main shaft for rotation therewith. The drive lever is driven by a device such as a fluid pressure operated piston cylinder combination and when it moves the tappet engages the cam face and rotates the cam with the main shaft to a second position which is predetermined. The mechanism also includes a stop which is effected between a face of the cam and a lever member which is shifted by the drive lever to stop the backward movement of the cam with the main shaft at a precise second position.

Abstract: Sewing machine needle positioning devices to position a sewing machine needle to selected location with respect to a work surface where the sewing machine includes a rotatable drive shaft to drive the needle and stitching mechanism. A clutch wheel is attached to the drive shaft to rotate the drive shaft when the clutch is rotated in a first direction. A cam is located on a drive shaft extension to engage a cooperative pressure plate carried by a gear rack assembly which is moved bidirectionally along a selected axis to engage a gear carried by the clutch to rotate the shaft in the first direction where the gear rack moves in one linear direction until the cam engages the pressure plate to stop the machine when the clutch has rotated it in the first direction to a selected position where the needle is in selected location with respect to the work surface.

Abstract: The disclosure concerns a drive device for a double thread chain-stitch buttonhole sewing machine. The machine has a first drive shaft for driving the sewing needle and for moving the cloth support plate for sewing. It has a separate worm shaft for moving the cloth support plate to the sewing position and also for operating a knife for cutting the buttonhole. A first respective electromagnetic clutch operates the sewing needle drive shaft, and a second respective electromagnetic clutch operates an intermediate shaft which then operates the worm shaft for operating the cloth support plate and knife operating shaft are provided. A drive shaft is connected with the armature part of the first electromagnetic clutch on the sewing needle driving shaft. That armature part is gear connected with an armature part of the second clutch on the intermediate shaft.

Abstract: A lockstitch sewing machine has a needle (22) and awl (24) mounted on a common pivot (52) and actuated each by a crank mechanism (40;72), the two mechanisms being mounted on a common crank shaft (38). Each mechanism is constituted by a bell crank lever (44;76); the two levers also being mounted on a common pivot (46). This latter pivot (46) is disposed intermediate the pivot (52) for the needle and awl and the crank shaft (38).

Abstract: A lockstitch sewing machine has, in addition to stitch forming instrumentalities (22, 24), a needle thread control arrangement (32) by which the tension in the needle thread (T2) is controlled during stitch formation. In addition, said arrangement (32) ensures that each formed stitch is drawn into the body of the workpiece, by pulling on the thread while it remains clamped by thread clamping means (200, 202). This pulling takes place in the early stages of the formation of the next stitch so that, at the end of the machine stitching cycle, the final stitch is not set by this arrangement (32). Instead, electrically actuated stitch setting means (220 to 226) is provided operable in response to an "end of cycle" signal supplied by control means by which further "end of cycle" functions (e.g. release of a presser foot (36) and of the thread clamping means (200, 202) are also controlled.

Abstract: A thread changing mechanism for sewing machines includes a magazine in which a plurality of needle holders is received, to be positively coupled to the sewing machine needle bar by a vertical motion of the magazine. Upon effecting a coupling, the magazine is retracted into a starting position remote from the needle bar, so that the needle bar with the needle holder can unobstructedly move during the sewing operation. The thread changing mechanism is mounted on a sewing machine as an attachment later, without particular adjustments. When the needle holders are held in the magazine the thread is engaged with each needle and held out of the way of the operating needle thread.

Abstract: A device for driving a sewing machine which includes a main shaft driven by a positioning motor that can be stopped in at least one predetermined position and then returned back to a second predetermined position, comprises a coupling disc which can be moved into engagement with a drive disc associated with the motor and a main shaft to drive the main shaft in a direction opposite to its normal direction of operation as determined by the positioning motor. The coupling disc is provided with cam surfaces with a cam engaging surface provided on a supporting member which is biased toward the disc by a predetermined tension. An actuator is connected to the support for rotating the actuator. The initial rotation moves the coupling disc into engagement with the driver disc which is connected to the main shaft, and the further rotation of the support rotates both the coupling and main shaft by a predetermined amount.

Abstract: A sewing machine in which the start and stop of a main shaft is controlled by a cam mechanism through a motion control mechanism at the sewing cycle corresponding to a predetermined number of stitches. The working position of a work holder is controlled by positional data in original instructions stored in a memory. Additional instruction corresponding to the number of stitches to reach the next stop time point controlled by the cam mechanism is prepared for back-tacking, unless the number of stitches corresponding to the original instructions are equal to an integral multiple of the predetermined number of stitches.

Abstract: The specification relates to accessory device to be used in conjunction with a sewing machine having an automatic thread cutter. The accessory device is provided for enlarging the passageway between the sewing foot and the stitch plate, to enable bulky articles to be moved within said passageway at the time the thread is cut. The device includes a push-back mechanism comprising brake jaws as engaging elements acting upon the drive and mounted on an entrainer operationally connected with an activating device for the purpose of engaging the drive by means of said engaging elements, to push it back and bring the needle bar into its upper position, while the thread feeder remains in its lower position. The obtainable increase in the height of the passageway may be as high as 30%.

Abstract: A sewing machine having two needles supported in a needle holder, which needle holder is horizontally displacable, to present one needle to an active workstation in a prethreaded manner and simultaneously shift the other needle which has a different thread therein, into an adjacent inactive position. As the needles are being shifted, the needle moving to inactive status has its thread clamped against the needle holder by a wheel, to secure the thread from being pulled therefrom or straying. A vacuum tube arranged at each respective inactive position or station sucks the tail of the thread therein. A pair of thread guides, one for each thread, are arranged for vertical movement, to pullback on the dangling thread of the inactive needle, to prevent the thread from whipping during its inactive status. Each thread passes around a thread engaging wheel comprising a dual bobbin monitor arranged on a single axis.

Abstract: A phase indication device of the invention is provided for a sewing machine for electrically indicating a predetermined angular position of a main drive shaft and showing that the sewing machine is ready for starting a stitching operation. The phase indication device comprises first and second detection means, electric circuit and an electric indicator. The first detection means produces a first electric signal when detecting the predetermined angular position of the main drive shaft. The second detection means produces a second electric signal when detecting the drive motor being deenergized. The electric circuit is operative to produce an output to lighten the electric indicator when the circuit receives both of the first and second electric signals.

Abstract: The arrangement comprises a sewing apparatus which is partially supported below a material-supporting table and which partially extends through an opening above the table surface. Control means are provided to control the operation of the sewing apparatus as well as to feed the material to be sewn along each direction in which a seam is to be formed. Sensing means are provided to sense the fact that a seam has been completed. Also, means are provided which clamp the material to the table after each seam is sewn. The control means further include means to rotate the sewing apparatus and align it in such a way that when the material is again fed to the sewing apparatus, the latter sews a successive seam along a different selected direction.

Abstract: A pneumatic needle positioner for positioning a needle of sewing and stitching machines in a predetermined position in the sewing or stitching cycle is provided by utilizing a handwheel sensing device in cooperation with a pneumatically powered positioning motor engageably disposed relative to a drive V-belt which engages the V-belt with a V-belt pulley of the pneumatic needle positioning motor at the end of the sewing cycle, by the actuation of a biasing piston having a roller to tension the V-belt toward the pulley disposed on the pneumatically powered positioning motor. Preferably the biasing piston and roller for the pneumatically powered positioning motor is disposed slightly above or below an axially adjacent position to the air motor pulley to provide a sinesoidal shaped bias against the pnematically powered positioning motor pulley to more effectively cooperate with the positioning device to achieve a more reliable and accurate positioning of the needle.

Abstract: A needle positioner for a sewing machine having a shaft connected to a main drive motor to move a sewing machine needle reciprocally by a stitching operation which includes a crank rotatably supported on a frame drivably connected to the sewing machine shaft with a plurality of pneumatically actuated cylinder/piston assemblies, the pistons of which are engagable with the crank to move the crank and therefore the shaft through predetermined rotary angles together with a plurality of conduits having valves including control valves therein which are adapted to communicate the cylinder/piston assemblies with a source of pneumatic pressure so that selective actuation of the control valves produces rotary movements of the crank through the appropriate cylinder/piston assembly to move the needle into either a top or bottom position.

Abstract: A device for locating the needle of a sewing machine in a preselected position upon completion of a sewing operation. The device includes a control shaft operatively connected to the needle and by driving elements, to a clutch brake type operating motor. A cylindrical member having a reference pin extending radially from its periphery is fixed on the control shaft and is operatively connected to an auxiliary actuator which when the machine is stopped is caused by a control apparatus to rotate the cylindrical member and its reference pin. The control apparatus is also effective in moving a stud into the pathway of the reference pin and when the two engage one another, the cylindrical member and control shaft are stopped which positions the needle in a preselected position.

Abstract: A sewing machine comprises an upper shaft adapted in a known manner to reciprocate the needle of the sewing machine. A motor-driven pulley is freely turnable on the shaft and normally connected to the latter by a clutch. A stop cam having an engaging face is fixed to the shaft for rotation therewith and a stop lever is movable by a manually operated lever between an inoperative position located out of the path of rotation of the engaging face and an operating position in the path of the latter to stop rotation of the cam and therewith the shaft upon engagement of the stop lever with the engaging face. Elements cooperating with the stop cam cooperate with the clutch to disconnect the pulley from the shaft when the stop lever blocks rotation of the stop cam.

Abstract: A sewing machine is provided with a needle thread cutting device for severing the free end of the needle thread extending through the eye of the needle at the beginning of a sewing operation to prevent entanglement of the free end with the stitches being formed. A cutter element is mounted for oscillating movement in conjunction with the raising and lowering of the presser foot. The lower end of the cutter element is provided with a transverse leg extending across the upper surface of the presser foot in close proximity thereto rearwardly of the needle. The transverse leg portion is provided with a cutting edge on the side thereof remote from the needle.

Abstract: A needle positioning attachment connectable to the main drive shaft of a sewing machine in place of a pulley and handwheel assembly conventionally found on blind stitch and similar machines includes a resilient assembly for accumulating energy from rotation of the main drive shaft of the machine so as to use this accumulated energy for actuation of the needle positioning attachment when the main drive shaft ceases rotation. In this manner, the needle of the sewing machine will be positioned as desired for starting a new sewing operation each time the machine is deactuated.

Abstract: A sewing machine for making continuous and intermittent stitches has a main shaft which is continuously rotated by a pulley and a clutch mechanism during the making of continuous stitches. The clutch mechanism is repeatedly disengaged by a blocking device when the machine makes intermittent stitches. The blocking device is rotatable, within limits, on the main shaft and can be arrested by a pawl which is mounted on a holder controlled by a stitch selecting cam. The cam can move the pawl nearer to or further away from the blocking device and the pawl has a follower which is located in the path of movement of a second cam, which is integral with the blocking device or rotates with the main shaft, when the stitch selecting cam has moved the pawl nearer to the blocking device whereby the rotating second cam pivots a pallet of the pawl into the path of movement of a shoulder on the blocking device.

Abstract: A sewing machine has a housing and a needle displaceable on the housing between a down position engaging through a workpiece and an up position disengaged therefrom. A drive is connected to a drive wheel rotatable on a drive shaft in the housing that in itself is operatively connected to the needle. A clutch including a clutch member on the shaft between the shaft and the wheel has a control element displaceable between an engaged position for rotationally coupling the wheel and the shaft and a disengaged position for free relative rotation of the wheel and the shaft. Thus in the engaged position of the clutch the drive can vertically reciprocate the needle between its up and down positions. A stopper member having an engaging part is mounted on the shaft and a stopper is mounted on the housing.

Abstract: A sewing machine motor is connected to a drive wheel which can be connected via a clutch to a drive shaft that vertically reciprocates the sewing-machine needle. A cam on the shaft and a stopper on the housing are displaceable between an operative position engageable with each other for stopping rotation of the shaft in a predetermined angular position corresponding to the up position of the needle and an inoperative position unengageable with each other. A cam is provided for displacing the control element of the clutch from an engaged to a disengaged clutch position on engagement of the stopper in its operative position with the cam so that the shaft can be arrested in a predetermined angular position and is substantially simultaneously rotationally uncoupled from the wheel.

Abstract: A sewing machine operated by a foot controller is provided with a mechanism for stopping the main shaft of the sewing machine in a predetermined position of each revolution thereof, thus to intermittently drive the sewing machine to produce intermittent stitches. The mechanism can be made inoperative allowing the main shaft to continuously rotate, thereby to produce the ordinary continuous stitches.

Abstract: A stopping device for an eyelet button holing machine provides a stopper arm which plunges into a recess portion of a stopper cam positioned coaxial to the main shaft. To absorb the stopping impulse, extra wheel cams are provided coaxial to the main shaft which induce the stopper arm to be inclined such that its position causes a clutch pulley to contact with a low speed pulley and then the stopper arm plunges into the recess portion of the stopper cam. Thus, the machine is stopped in two steps and the stopping impulse force is effectively alleviated.