38 results about "Feed dogs" patented technology

The utility model provides a kind of movement device of cylinder sewing machine feed dog, belong to sewing machine technical field.It solves the problem that existing feed dog movement device is not applicable to cylinder sewing machine.This sewing machine includes the cabinet with long arm, the first end of swing arm is fixed with feed dog, the middle part of swing arm is hinged with long arm, the first end of lifting tooth bar is hinged with long arm, the first end of lifting tooth bar is located directly below the first end of swing arm, lower shaft can drive swing arm swing back and forth around its hinged point by feeding assembly, lower shaft can drive lifting tooth bar swing up and down around its hinged point by lifting tooth assembly, the first end of lifting tooth bar swing upwards can make the first end of swing arm move upwards, swing arm can make the first end of swing arm move downwards under the action of its elasticity.This movement device of cylinder sewing machine feed dog has the advantages of reasonable use of space, smooth movement of cylinder sewing machine feed dog.

The invention provides a sewing machine feed dog adjusting device and a sewing machine, the sewing machine feed dog adjusting device comprises a bottom plate, a feed dog lifting shaft, a feed dog frame, a feed dog, a feed dog lifting crank, a feed dog lifting connecting rod, a feed dog lifting adjusting eccentric pin and a feed dog lifting adjusting knob, the feed dog lifting crank is fixed on the feed dog lifting shaft, and the feed dog lifting adjusting eccentric pin comprises a first shaft part and a second shaft part which are eccentrically arranged; the first shaft part is in running fit with the feed lifting crank and is fixed with the feed lifting adjusting knob, the second shaft part is in running fit with one end of the feed lifting connecting rod, and the other end of the feed lifting connecting rod is hinged with the feed rack; the feed lifting crank and the feed lifting adjusting knob are respectively provided with a plurality of adjusting positioning grooves and telescopic adjusting positioning pieces; when the feed lifting adjusting knob is rotated, the feed lifting adjusting eccentric pin synchronously rotates along with the feed lifting adjusting knob, the relative position between the second shaft part and the feed lifting connecting rod is changed, and the adjusting positioning piece moves out of the current adjusting positioning groove and is clamped into the other adjusting positioning groove. The height of the feeding teeth can be easily and conveniently adjusted by a lathe worker.

Sewing machine (100), including: a needle vertical movement mechanism which moves a needle bar up and down; a sewing machine motor (16) which drives the needle vertical movement mechanism as a drive source; a transporter holder (32) which holds a transporter (31) which transports a workpiece on a needle plate; a horizontal transport mechanism which receives a driving force from the sewing machine motor (16) and transmits a horizontal back-and-forth movement to the feed dog support (32); and a vertical transport mechanism which imparts a vertical back-and-forth movement to the transporter holder (32), wherein the horizontal transport mechanism includes a transport adjustment motor (57) which changes and adjusts the division of the horizontal reciprocating movement by the sewing machine motor (16) with respect to the feed dog support (32), the vertical transport mechanism comprises a vertical transport motor (66) which provides the vertical reciprocating movement with respect to the transporter support (32) as a drive source, the sewing machine (100) includes a control device (90) which controls the feed adjustment motor (57) and the vertical feed motor (66) in order to cause the feed dog (31) to transport the workpiece, the control device (90) controls the vertical transport motor (66) in such a way that the feed dog (31) performs a circular movement along a predetermined path in synchronization with a rotation angle of a main shaft which is rotatably driven by the sewing machine motor (16), and controls the vertical transport motor (66) in such a way that a path of the feed dog (31) in a transport section is corrected according to a rotation speed of the main shaft.

The invention provides a method for controlling the uniform stitch length of a sewing machine. The method comprises the following steps that S1, a plurality of adjusting stitch length values and a plurality of adjusting motor output swing angles are preset in a controller; s2, in the process that the feed dog executes the nth cloth feeding action, recording the moment when the feed dog protrudes upwards from the needle plate and jacks up the sewing material as t1n, recording the moment when the feed dog is located at the highest point as t2n, recording the set moment between the t1n and t2n as t3n, and obtaining sewing material thickness values H1n and H3n respectively by a thickness detection mechanism at the t1n moment and the t3n moment; the controller obtains an adjusting needle pitch value Dn according to the H1n and the H3n and controls the output shaft of the adjusting motor to be at an output swing angle corresponding to the Dn, and n is a positive integer. The control method provided by the invention has the beneficial effects that by adopting the control method provided by the invention, the change condition of the thickness of the sewing material can be obtained in real time and the stitch length can be adjusted in time in the process of sewing each stitch by the sewing machine, so that the stitch length cannot be suddenly changed, and the uniformity of the stitch length on the sewing material is ensured.

The invention provides a sewing machine feed dog adjusting device and a sewing machine, the sewing machine feed dog adjusting device comprises a fixedly arranged base plate, a feed dog lifting shaft rotatably supported in the base plate, a feed dog frame, a feed dog fixed on the feed dog frame and a transmission adjusting assembly, and the transmission adjusting assembly is in transmission connection between the feed dog lifting shaft and the feed dog frame. The transmission adjusting assembly is provided with an adjusting execution part for a user to operate, a locking structure is further arranged between every two adjacent parts in the transmission adjusting assembly, and the locking structures are used for keeping the relative positions of the two adjacent parts; when a user operates the adjusting execution part, the height of the feeding teeth during follow-up operation of the sewing machine is changed, and the current relative positions of the two adjacent parts are changed, so that a turner can easily and conveniently adjust the height of the feeding teeth. The relative positions of the two adjacent parts are locked through the locking structures, so that the height of the feeding teeth is locked after each time of adjustment. The sewing machine is simple in overall structure and low in cost, the overall cost of the sewing machine is reduced, and competitiveness is improved.

This invention provides a feed mechanism for an overlock sewing machine that solves the problem of the significant amount of adjustment required to change the main feed momentum and differential feed momentum compared to conventional methods. [Solution] The overlock sewing machine's feed system comprises a fabric feed mechanism 3 equipped with a main feed dog 20, differential feed dog 21, main feed table 22, differential feed table 23, feed up / down mechanism 30, main feed forward / backward mechanism 4, and differential feed forward / backward mechanism 5; a feed amount adjustment mechanism 6 equipped with a main feed amount adjustment mechanism 7 including a first stepping motor 73 and a differential feed amount adjustment mechanism 8 including a second stepping motor 83; and control devices and input devices for the first stepping motor 73 and the second stepping motor 83.

The utility model provides a kind of sewing machine's feed dog adjusting device, including driving motor, transmission assembly and adjusting assembly, driving motor swings adjusting assembly by transmission assembly drive, adjusting assembly is used to adjust the angle size of differential feeding shaft positive, reverse swing;Adjusting assembly includes adjusting seat, transmission assembly includes slider and the sliding slot in the side of adjusting seat, slider is fixed on the output shaft of driving motor, adjusting shaft is parallel to the output shaft of driving motor and is arranged, slider is slidably arranged in sliding slot, driving motor drives slider rotation, slider drives adjusting seat swing.This sewing machine's feed dog adjusting device realizes feed dog automatic regulation by driving motor, transmission assembly so that it can be according to the size of space in casing reasonably arrange the installation position of driving motor, compact structure, suitable for sewing machine casing of space limited, wide application range, traditional stability.

To provide a sewing device in which the degree of freedom in setting the length of a needle thread and a bobbin thread is improved more than before.SOLUTION: A control device of a sewing machine drives a needle bar mechanism and a feed dog, and executes sewing work for forming a seam on a workpiece with a thread (S7). The control device executes a yarn catching process of moving the movable blade from the standby position to a yarn catching position where the movable blade catches the yarn, and further moving the movable blade to a movable position on a side opposite to the standby position with respect to the yarn catching position. The control device executes length adjustment processing for positioning the lower end of the needle above the throat plate to make the workpiece movable in a state where the movable blade catches the thread by the thread catching processing (S11). After the length adjustment processing, the control device executes cut processing for moving the movable blade to a cut position where the movable blade crosses the fixed blade and cutting the thread (S14).SELECTED DRAWING: Figure 10

The utility model discloses an anti-bite clamp, which belongs to the technical field of dog training instruments and comprises a base plate, dog food can be placed in the base plate, a clamping component is arranged on the base plate, the clamping component can be folded or unfolded relative to the base plate, when the clamping component is folded, the clamping component clamps the dog food or a dog basin or blocks the dog food in the base plate, and when the clamping component is unfolded, the clamping component can clamp the dog food or the dog basin or blocks the dog food in the base plate. The clamping assembly cancels blocking of the dog food in the chassis, the chassis is connected with a connecting assembly, the connecting assembly is provided with a control assembly, and the clamping assembly is controlled to be folded or unfolded through the control assembly. The clamping assembly is used for clamping a dog basin and dog food to feed dogs, the clamping assembly can also be used for grabbing the dog food and holding the dog food in the base plate, when the clamping assembly is closed, the dog food is blocked, the dogs cannot eat food, and when the dogs need to eat food, the clamping assembly is opened, the dog food in the base plate is exposed, and the dogs can eat food. The feeding rhythm of the dog is controlled, and the mood of the dog is stabilized to train the dog.

The oral liquid feeding device for the sea-buckthorn zinc dogs comprises a placing frame, a storage bottle used for storing oral liquid for the sea-buckthorn zinc dogs is placed in the placing frame, an installation cavity is formed in the placing frame, a water basin used for feeding the dogs is installed in the installation cavity, and the cavity wall of the installation cavity makes contact with the water basin to conduct vertical positioning and transverse positioning on the water basin. A bayonet is formed in the rear portion of the water basin, a cam is rotationally installed on the placing frame, the cam is transversely clamped into the bayonet to clamp the water basin so as to longitudinally position the water basin, the cam is exposed to be operated and rotated by people, and the rotating shaft is a longitudinal shaft. The cavity wall of the mounting cavity is used for vertically and transversely positioning the basin, and the cam is transversely clamped into the bayonet to clamp the basin so as to longitudinally position the basin, so that the basin can be effectively fixed. During feeding, the water basin is not easily pulled out and knocked over by dogs. When a user needs to move the water basin, the cam is operated to rotate to be separated out of the bayonet, so that the cam does not clamp the water basin any more, and extra resistance cannot be brought to the movement of the water basin.

To provide a sewing machine contributing to improvement in operability of a workpiece when a user manually moves the workpiece in execution of free motion sewing.SOLUTION: A processor of the sewing machine drives a sewing machine motor in a state where an upper end of a feed dog is positioned below a throat plate, and executes free motion sewing processing for vertically moving a needle bar (S32, S35, S36). At least a part of a needle up period in which the lower end of the needle is above the throat plate is defined as a first period, and at least a part of a needle second half in which the lower end of the needle is below the throat plate is defined as a second period. The thread tension control processing includes adjusting a length of the spring in a pressure direction during a first period to a first length, and adjusting a length of the spring in the pressure direction during a second period to a second length shorter than the first length (S36).SELECTED DRAWING: Figure 9

This utility model discloses a novel small-head special multi-needle machine, including a needle clamp with multiple sets of needle mounting slots distributed on it. Each needle mounting slot contains a longitudinal needle. A needle plate is located below the needle clamp, and a feed dog is located below the needle plate. The needle plate has multiple sets of needle holes (B) that mate with the multiple longitudinal needles. The needle plate also has a set of feed dog grooves that mate with the teeth of the feed dog, with each tooth of the feed dog extending into the set of feed dog grooves. A needle presser foot is located above the needle plate, and the needle presser foot has a set of needle holes (A) that align with the sets of needle holes (B) and the longitudinal needles. The design allows for the simultaneous installation of multiple longitudinal needles in the needle clamp, and also includes a needle presser foot, needle plate, feed dog, and curved needle holder that can work with any number of longitudinal needles within a given range. The number of longitudinal needles on the needle clamp can be flexibly adjusted according to specific work requirements, making the overall operation more convenient and flexible.

The utility model discloses a feeding tooth structure and a sewing machine in the technical field of sewing machines. The feeding tooth structure comprises a feeding tooth body. The feeding main tooth is arranged above the feeding tooth body; and the auxiliary feeding teeth are arranged on one side of the main feeding teeth, the auxiliary feeding teeth are connected with the feeding tooth body, and the upper surfaces of the auxiliary feeding teeth are located above the upper surfaces of the main feeding teeth. The independent feeding mode is adopted, the auxiliary feeding teeth with the adjustable height are installed on one side of the main feeding teeth, the difference between the cloth feeding efficiency of upper-layer fabric and the cloth feeding efficiency of lower-layer fabric can be reduced, the phenomenon that the upper-layer fabric and the lower-layer fabric are staggered is avoided, and the cloth feeding device has the advantages of being simple in structure, low in cost and convenient to adjust. The method can be better accepted by clients.

This invention relates to a sewing method for preventing needle breakage in a sewing machine, comprising: a standard sewing mode: the feed dog moves along a set trajectory, the main shaft rotates at a uniform speed Va and drives the needle to move, and within one operating cycle time T, the time corresponding to when the needle tip is successively located at the needle plate plane, the highest position B, and the needle plate plane after the needle starts moving from the lowest point A is t. C t B and t D Thick-material anti-needle breakage sewing mode: The feed dog trajectory is the same as in the standard sewing mode, and the relationship between the spindle angle and the needle position is also the same; within the cycle time T, there are time points t0, t1, t2, t3, and t4. During the time period t0 to t2, the spindle decelerates; during the time period t0 to t1, the spindle speed is greater than Va; during the time period t1 to t2, the spindle speed is less than Va. The time when the needle tip is located on the needle plate plane is recorded as t. C0 , t C0 <t C During the time interval t2 to t4, the spindle accelerates; during the time interval t2 to t3, the spindle speed is less than Va; during the time interval t3 to t4, the spindle speed is greater than Va. The time when the needle tip is on the needle plate plane is recorded as t. D0 , t D0 >t D .

A stitch starting method for preventing material backfeeding in sewing a thick material by a sewing machine, comprising: on the basis of the size of a thick material (8) and the size of a presser foot (3) and the friction between the thick material and a needle plate (2), setting an anti-pushing reference position and a first stitch minimum stitch length ∆S, wherein when the thick material is located at the anti-pushing reference position, the distance between the front edge of a stitch starting position of the thick material and the central axis of a needle (4) is ∆S, an included angle θ between a lower pressing plane (31) and the surface of the needle plate is 0°, or tan (90°-θ)≥1 / μ; on the basis of the first stitch minimum stitch length ∆S and a placement position of the thick material on the needle plate, determining a position I of a feed dog (1) and a first feeding distance L1; before the thick material is placed, a main shaft (5) not moving, the feed dog first moving to the position I and stopping to place the thick material at the placement position, and the presser foot (3) pressing against the thick material; starting stitching, the feed dog being kept at the position I, and the main shaft first rotating to an angle A; and a feeding driving mechanism (7), a feed dog lifting driving mechanism (6) and the main shaft moving synchronously, the feed dog driving the thick material to move in a cloth feeding direction, and when reaching a position II, the feed dog just sinking below an upper surface of the needle plate, thereby completing first feeding. In the stitch starting method, the movement relationship between the feed dog and the needle is controlled when at the start of stitching, especially at the first stitch, enhancing support of the thick material in the horizontal direction by the feed dog and the friction, and effectively preventing the thick material from being pushed out by the presser foot at the start of stitching. In addition, provided is a se

The utility model belongs to the technical field of sewing machines, and particularly relates to a cloth feeding mechanism of a sewing machine, which comprises a feed dog frame, the tooth feeding assembly is connected to one end of the tooth frame and used for driving the tooth frame to move left and right; the feed lifting assembly is connected to the other end of the feed rack and used for driving the feed rack to move up and down; the feed lifting assembly comprises a feed lifting cam, a feed lifting connecting rod and a traction connecting rod, one end of the traction connecting rod is used for being hinged to a rack, and the other end of the traction connecting rod is hinged to the output end of the feed lifting crank. The lifting period of the feed dog frame is changed through the feed lifting connecting rod and the traction connecting rod, so that when the feed lifting assembly drives the feed dog frame to be lifted, the feed dog assembly can synchronously drive the feed dog frame to move left and right, and therefore a movement track which is overall in an oval shape is formed, and the cloth feeding mechanism has a better cloth feeding effect.

This invention belongs to the field of sewing machine technology, specifically relating to a lower feeding mechanism for a sewing machine, including a motor, a feeding shaft assembly, and a feed dog lifting shaft. A feeding crank (first) is mounted at the rear end of the outer feeding shaft, and a feeding crank (second) is mounted at the rear end of the inner feeding shaft extending from the outer feeding shaft. The other end of the second feeding crank is connected to a motor connecting rod, and the other end of the motor connecting rod is connected to a motor crank, which is mounted on the outer circumference of the motor's main shaft. A feed dog lifting crank is mounted at the rear end of the feed dog lifting shaft. A synchronous connecting rod (first) connects the first feeding crank to the feed dog lifting crank, and a synchronous connecting rod (second) connects the second feeding crank to the feed dog lifting crank. A feed dog lifting crank (first) is mounted at the front end of the outer feeding shaft, and a feed dog lifting crank (second) extends from the front end of the inner feeding shaft extending from the outer feeding shaft. Through the design of the motor, this invention allows for individual control of the speed of the lower feeding dog, thereby adjusting the fabric feeding speed and enabling diverse sewing operations. Operation and control are convenient.

Provided is a sewing machine comprising: a feed dog drive mechanism to drive a feed dog; a switching mechanism connected to the feed dog drive mechanism and configured to be slid in a right-left direction to switch between an operating state and a non-operating state of the feed dog; and a carriage drive mechanism to drive a carriage which holds an embroidery frame, wherein the carriage drive mechanism is configured to be switchable between an unfolded state and a folded state thereof, and the carriage and the switching mechanism are configured to form, in the folded state, a state in which the carriage can press the switching mechanism to slide the switching mechanism, whereby when the carriage is moved in the eight-left direction in the folded state, the switching mechanism is slid, and thus the operating state and the non-operating state of the feed dog are switched therebetween.

A sewing machine assembly includes a sewing machine frame, a presser bar mounted to a frame head of the sewing machine frame, and a feed dog assembly. The feed dog assembly includes a feed dog mounted to the frame base to reciprocate vertically and horizontally relative to the frame base to pull fabric between the pressure bar and the frame base through the sewing machine frame, a feed dog drive system coupled to the feed dog to drive reciprocation of the feed dog relative to the frame base, and a feed dog cover selectively coupled to a frame base of the sewing machine frame to extend over the feed dog to shield the fabric from the feed dog.

The application relates to an encryption sewing method and a lockstitch machine. The encryption sewing method comprises the following steps: a, adjusting the rotating angle alpha of a motor, controlling the position of a presser plate to be fixed relative to a needle plate, and controlling the moving track of a feed dog to move a preset distance x away from the presser plate; b, a feed dog driving structure drives the feed dog to move along the moving track, drives the cloth on the needle plate to move, and performs encryption sewing on the cloth; the moving track of the feed dog is controlled to move away from the presser plate by adjusting the motor, so that the single cloth feeding distance d of the feed dog is reduced, and the sewing stitch of the cloth is reduced; meanwhile, the position of the presser plate is controlled to be fixed relative to the needle plate by the adjusting motor, so that the change of the single cloth feeding distance d of the feed dog is only affected by the preset distance x, variables introduced due to the movement of the presser plate are reduced, the user can control the single cloth feeding distance d of the feed dog, and the adjusting difficulty is reduced.

This invention provides a feeding mechanism for adjusting the spindle drive amplitude of a sewing machine, comprising: a spindle, a rear slide block, and a reciprocating starting structure; a rear receiving groove is provided at the rear end of the feed dog; the rear slide block is disposed in the rear receiving groove; the spindle is connected to the rear slide block via the reciprocating starting structure; the reciprocating starting structure includes a rear slide block amplitude adjustment component; the rear slide block amplitude adjustment component is disposed on the spindle; the rear slide block amplitude adjustment component is connected to the intermediate transmission component via an output connecting rod; the intermediate transmission component is connected to the rear crank. This invention enables new up-and-down motion patterns during feeding, thereby generating new motion patterns in the feed dog, to meet the needs of adjusting the spindle drive amplitude of sewing machines used in different sewing scenarios.

This invention provides a method for controlling uniform stitch length in a sewing machine, comprising the following steps: S1, preset multiple adjustable stitch length values ​​and multiple adjustable motor output swing angles in the controller; S2, during the nth feeding action of the feed dog, the moment when the feed dog emerges from the needle plate and lifts the fabric is recorded as t. 1n The moment when the feed tooth reaches its highest point is denoted as t. 2n , will be in t 1n and t 2n The time interval between times is denoted as t. 3n Thickness testing agency at t 1n Time and t 3n The thickness value H of the seam material is obtained at different times. 1n and H 3n The controller is based on H 1n and H 3n Obtain the adjustment stitch length value D n And control the output shaft of the regulating motor to be in the same position as D n The corresponding output swing angle, where n is a positive integer. The advantage of this invention is that, using the control method provided by this invention, the change in fabric thickness can be acquired in real time during each stitch of the sewing machine, and the stitch length can be adjusted promptly to ensure that there are no sudden changes in stitch length and to guarantee uniform stitch length on the fabric.

This invention provides a thickness adjustment device for a sewing machine, belonging to the field of sewing machine technology. It solves the problem of cumbersome adjustment in existing thickness adjustment mechanisms. The sewing machine includes a housing, a feed dog, and an eccentric shaft. One end of the eccentric shaft is connected to the feed dog. The adjustment mechanism includes an electromagnet, a mounting bracket, a linkage rod, a limit rod, an elastic element, a limit wheel fixed to the other end of the eccentric shaft, and a driver fixed to the housing. The electromagnet is fixed to the housing via the mounting bracket, which has several stop holes. A stop plate is fixed to the core of the electromagnet, and a stop pin is fixed to the stop plate. The top of the linkage rod is hinged to the stop plate, and the bottom is hinged to the limit rod. The limit wheel has a protruding limit part that abuts against the limit rod under the action of the elastic element. A circumferential positioning structure is provided between the core of the electromagnet and the output shaft of the driver. This thickness adjustment device for a sewing machine has the advantage of convenient adjustment.

Sewing machine (100), including: a needle vertical movement mechanism which moves a needle bar up and down; a sewing machine motor (16) which drives the needle vertical movement mechanism as a drive source; a transporter holder (32) which holds a transporter (31) which transports a workpiece on a needle plate (11); a horizontal transport mechanism (40) which receives a driving force from the sewing machine motor (16) and transmits a horizontal back-and-forth movement to the feed dog support (32); a vertical transport mechanism (60B) which imparts a vertical back-and-forth movement to the transporter holder (32); a press foot (71) which presses the workpiece from above; and a press height detection unit (76) which detects a height of the press foot (71), wherein the horizontal transport mechanism (40) includes a transport adjustment motor (57) which changes and adjusts the division of the horizontal reciprocating movement by the sewing machine motor (16) with respect to the feed dog support (32), the vertical transport mechanism (60B) comprises a vertical transport motor (66) which provides the vertical reciprocating movement with respect to the feed dog support (32) as a drive source, and wherein the sewing machine (100) comprises a control device (90) which controls the vertical transport motor (66) to increase the height of the feed dog (31) in a transport section when the presser height detection unit (76) detects that the presser foot (71) is running over a stepped part of a thicker area of ​​the workpiece.

This invention discloses a pneumatic alignment and anti-wrinkle device for fabric edges in an overlock machine, relating to the field of overlock technology. It includes a sewing station with an overlock machine fixedly connected to its top. A top anti-wrinkle machine is placed at the top of the sewing station and behind the overlock machine. A telescopic drive is fixedly installed on the left side of the top anti-wrinkle machine. This device achieves precise control of the tension between the upper and lower fabric layers, solving a key technological pain point: existing technologies rely on operator feel or fixed mechanical limits to control fabric tension, making it difficult to maintain stability. This patent actively and precisely adjusts the clamping force of the first and second pressure rollers on the lower fabric layer by using a second cylinder to push a slider and a second pressure roller. This design applies a "rightward counterforce" to the lower fabric layer to counteract the "leftward pull" of the sewing machine's feed dogs, thereby precisely controlling the tension difference between the upper and lower fabric layers.

This device for adjusting the presser foot lift and feed dog tilt of an overlock sewing machine solves problems such as the increased cost and price of the sewing machine due to the need for separate drive mechanisms for presser foot lift and drop feed compared to conventional methods, and the inability of these drive mechanisms to adjust the tilt of the differential feed dog. [Solution] The presser foot lifting and feed dog tilt adjustment device of the overlock sewing machine comprises a stepping motor 5, a feed dog tilt adjustment member 3 that is linked to the stepping motor 5, a presser foot lifting member 4 that is linked to the stepping motor 5, and a control device for the stepping motor 5.

The invention discloses a feeding tooth height adjusting mechanism of a lockstitch sewing machine, an adjusting method and the lockstitch sewing machine, the adjusting mechanism comprises a feeding shaft and a tooth lifting shaft, a tooth frame seat is fixed at one end of the feeding shaft, the tooth frame seat is hinged with one end of a tooth frame assembly, and the other end of the tooth frame assembly is slidably hinged with a tooth lifting fork-shaped crank fixed at one end of the tooth lifting shaft; a feed lifting rear fork-shaped crank is fixed to the other side of the feed lifting shaft and slidably hinged to one end of a feed lifting adjusting connecting rod, the other end of the feed lifting adjusting connecting rod is hinged to one end of a feed lifting adjusting front crank, and the other end of the feed lifting adjusting front crank is fixedly connected with one end of a feed lifting adjusting driving shaft. The feed lifting adjustment driving shaft penetrates through a feed lifting adjustment driving shaft sleeve fixedly connected with the bottom plate, and the other end of the feed lifting adjustment driving shaft is fixedly provided with a feed lifting adjustment wrench which abuts against the bottom plate and extends out of a notch of the machine shell. The height of the feeding teeth can be conveniently and quickly adjusted.

The present invention relates to the technical field of sewing machines, and in particular, to a control method for preventing needle breakage in a sewing machine. A thin material mode having a thin-material forward / reverse sewing non-switching angle range, and a thick material mode having a thick-material forward / reverse sewing non-switching angle range are set, wherein the height of a needle from the upper surface of a throat plate corresponding to the starting angle of the thick-material forward / reverse sewing non-switching angle range is greater than the height of the needle from the upper surface of the throat plate corresponding to the starting angle of the thin-material forward / reverse sewing non-switching angle range; and the ending angles of the thick-material and thin-material forward / reverse sewing non-switching angle ranges both correspond to a feed dog being lowered below the throat plate; and a fabric thickness threshold is set, wherein when the thickness of a sewn fabric does not exceed the fabric thickness threshold, a forward and reverse sewing switching operation is performed on the basis of the thin material mode, and when the thickness of the sewn fabric exceeds the fabric thickness threshold, the forward and reverse sewing switching operation is performed on the basis of the thick material mode. The present invention prevents needle breakage during sewing on thick materials, avoids an extra stitch during sewing on thin materials, and ensures a fast response during switching between forward and reverse sewing.

The utility model relates to an upper forking adjusting structure which comprises an adjusting rod and further comprises a moving rod and a driving structure, the length direction of the adjusting rod is vertical, the length direction of the moving rod is transverse, the moving rod is hinged to the top end of the adjusting rod by arranging a hinge shaft, and the length direction of the hinge shaft is horizontal and is perpendicular to the length direction of the moving rod; the driving structure drives the moving rod to slide back and forth along the length direction; the driving structure comprises a driving gear and a stepping motor, a moving rack is arranged on the moving rod, the driving gear is meshed with the moving rack, and the length direction of a rotating shaft of the driving gear is parallel to the length direction of the hinge shaft; the stepping motor drives the driving gear to rotate. According to the scheme, a worker can adjust the cloth feeding distance of the upper-layer feed dog through the gear switch, manual operation is not needed, adjustment is convenient, the stepping motor is provided with a brake, when the sewing machine is used, the stepping motor cannot be loosened, and the upper-layer feed dog is not prone to deviation.

A sewing path capable of improving the stretch rate, which is applied to the sewing process of a lockstitch sewing machine. The lockstitch sewing machine comprises a feed dog (9), a dog carrier (14), a feed electric motor (5), a feed transmission mechanism (6), a dog-lifting electric motor (7), a dog-lifting transmission mechanism (8), a spindle electric motor (1), a spindle (2), a spindle transmission mechanism (3), a sewing needle (4), and a control system, wherein the feed dog (9) is arranged on the dog carrier (14), and the feed electric motor (5) is connected to the dog carrier (14) by means of the feed transmission mechanism (6) and is configured to drive the dog carrier (14) to move back and forth; the dog-lifting electric motor (7) is connected to the dog carrier (14) by means of the dog-lifting transmission mechanism (8) and is configured to drive the dog carrier (14) to move up and down; and the spindle electric motor (1) drives, by means of the spindle (2) and the spindle transmission mechanism (3), the sewing needle (4) to move up and down. Further provided are a lockstitch sewing machine, and a sewing process based on a lockstitch sewing machine. By means of the coordinated movement of the spindle electric motor, the dog-lifting electric motor and the feed electric motor, a new movement path is realized, thereby achieving a higher stretch rate, and effectively broadening the adaptability to different types of sewing materials.