CN203475127U - Button hole sewing machine - Google Patents

Abstract

The utility model relates to a keyhole sewing machine. This buttonhole sewing machine accurately sews the ends of the upper thread into the buttonhole stitch. A buttonhole sewing machine includes: a cloth feeding mechanism for conveying cloth on a bed; a stitch forming mechanism for sewing keyhole stitches on the conveyed cloth using needles; and an upper thread holding mechanism for Cut the upper thread after sewing the keyhole stitch and keep the cut end of the upper thread. The upper thread holding mechanism includes: a thread cutting member capable of switching between an open state and a closed state; a plate portion for holding an end of the upper thread when the thread cutting member is in the closed state; In this state, the end of the upper thread that has been released by the plate is guided toward the keyhole stitch. When the thread cutting member is switched from the closed state to the open state after starting to sew the keyhole stitch, the end of the upper thread that has been released by the plate portion is guided to the keyhole stitch by the concave portion, so the buttonhole sewing machine accurately draws the upper thread The ends are sewn in keyhole stitching.

Description

Keyhole Sewing Machine

technical field

The utility model relates to a keyhole sewing machine.

Background technique

A conventional buttonhole sewing machine includes a thread cutting member with a pair of knives, and when the sewing of the previous buttonhole stitch is completed, the upper thread is cut by closing the pair of knives of the thread cutting member. The pair of knives in the closed state holds the end of the cut upper thread (hereinafter referred to as the upper thread end). A buttonhole sewing machine starts buttonhole stitching with a pair of knives in an open state, thereby releasing the end of the upper thread from the thread cutting member. The buttonhole sewing machine sews the end of the released upper thread into the next buttonhole stitch (for example, refer to Japanese Patent Laid-Open No. 35459 of 2002).

The thread cutting member of the buttonhole sewing machine holds the end of the upper thread extending from the eye of the needle on the downstream side in the stitch forming direction with respect to the needle when sewing a buttonhole stitch is started. In this state, the direction in which the end of the upper thread extends substantially coincides with the direction in which the stitches are formed, so that it is easy to sew the end of the upper thread into the buttonhole stitch.

After the keyhole stitching is started, if the upper thread end held by the thread cutting member is released, the released upper thread end will shake due to its own twisting or the like, and its position will be unstable. In this state, the position of the end of the upper thread deviates from the direction in which the end of the upper thread extends relative to the direction in which the stitches are formed. Therefore, the end of the upper thread may not be accurately sewn into the buttonhole stitch. If the end of the upper thread cannot be accurately sewn into the buttonhole stitch, the stitches may become irregular and poor stitch formation may occur.

Utility model content

The purpose of the utility model is to provide a buttonhole sewing machine which can accurately sew the end of the upper thread into the buttonhole stitch.

The buttonhole sewing machine according to claim 1 includes: a conveying mechanism for conveying the cloth placed on the machine base in a predetermined direction; sewing keyhole stitches on the above-mentioned cloth fed by the feeding mechanism; and an upper thread holding mechanism which is provided above the above-mentioned machine base and is provided at the position where the above-mentioned feeding mechanism feeds the cloth when the sewing of the above-mentioned buttonhole stitches starts. The upstream side of the above-mentioned machine needle in the direction is used for cutting the above-mentioned upper thread after the above-mentioned buttonhole stitch is sewn by the above-mentioned sewing mechanism and holding the end of the above-mentioned upper thread after being cut, that is, holding the end of the upper thread, In this buttonhole sewing machine, the above-mentioned upper thread holding mechanism includes: a thread cutting member, which is a pair of knives that are in an open state when the above-mentioned buttonhole stitch is sewn, and after the above-mentioned buttonhole stitch is sewn, , the pair of knives are switched from the open state to the closed state to cut the above-mentioned upper thread; the thread holding member is arranged on the above-mentioned thread cutting member, and is used to cut the cut end of the above-mentioned upper thread when the above-mentioned thread cutting member is in the above-mentioned closed state. A portion is held between the thread holding member and the above-mentioned thread cutting member; a knife opening and closing mechanism for switching the above-mentioned thread cutting member from the above-mentioned closed state to an open state after starting to sew the above-mentioned keyhole stitch; and a concave portion, which is provided In the thread cutting member, for guiding the upper thread released by the thread holding member toward the keyhole stitch made by the needle when the knife opening and closing mechanism switches the thread cutting member to the open state Ends.

In the above buttonhole sewing machine, when the thread cutting member is switched from the closed state to the open state after starting to sew the buttonhole stitch, the end of the upper thread that has been released by the thread holding member is guided to the buttonhole stitch by the recess. Therefore, the buttonhole sewing machine can accurately sew the ends of the upper thread into the buttonhole stitches.

In the buttonhole sewing machine according to claim 2, the thread cutting member has a fixed knife and a movable knife, and the movable knife is overlapped with the fixed knife and is movable on the needle side of the fixed knife so as to be positioned between the fixed knife and the fixed knife. The above-mentioned open state and the above-mentioned closed state are switched, the above-mentioned thread holding member is opposed to the above-mentioned movable knife on the opposite side of the above-mentioned fixed knife across the above-mentioned movable knife, and the above-mentioned recess is provided in the above-mentioned movable knife. side of the above needle side. In this case, the buttonhole sewing machine can accurately guide the end of the upper thread toward the buttonhole stitch located below the upper thread holding mechanism along the concave portion formed on the needle side surface of the movable knife.

In the buttonhole sewing machine according to claim 3, the concave portion extends from an upper end to a lower end on a side surface of the movable knife on the needle side. In this case, the buttonhole sewing machine can more accurately guide the end of the upper thread toward the buttonhole stitch located below the upper thread holding mechanism.

In the buttonhole sewing machine according to claim 4, the thread cutting member has a fixed knife and a movable knife, and the movable knife is overlapped with the fixed knife and is movable on the needle side of the fixed knife so as to be positioned between the fixed knife and the fixed knife. The above-mentioned open state is switched between the above-mentioned closed state, the above-mentioned thread holding member is opposite to the above-mentioned movable knife on the opposite side of the above-mentioned fixed knife across the above-mentioned movable knife, and the above-mentioned concave portion is continuously provided on the above-mentioned movable knife. A side surface of the knife on the side of the needle and an upper surface of the movable knife opposed to the thread holding member. In this case, the buttonhole sewing machine can accurately guide the end of the upper thread toward the buttonhole stitch located below the upper thread holding mechanism along the concave portion continuously formed on the upper surface and the side surface of the movable knife.

In the buttonhole sewing machine according to claim 5, the concave portion is inclined downward along the side surface on the needle side of the movable knife on the upper surface of the movable knife, and extends from an upper end on the needle side side surface of the movable knife. to the lower end. In this case, the buttonhole sewing machine can more accurately guide the end of the upper thread toward the buttonhole stitch located below the upper thread holding mechanism.

In the buttonhole sewing machine according to claim 6, the thread cutting member has a fixed knife and a movable knife, and the movable knife is movable on the needle side with respect to the fixed knife so as to be opened between the fixed knife and the fixed knife. state and the above-mentioned closed state, the above-mentioned thread holding member is opposite to the above-mentioned movable knife on the side opposite to the above-mentioned fixed knife with respect to the above-mentioned movable knife, and the above-mentioned recess is provided in the above-mentioned movable knife. Hold the opposing upper surfaces of the members. In this case, the buttonhole sewing machine can accurately guide the end of the upper thread toward the buttonhole stitch located below the upper thread holding mechanism along the concave portion formed on the upper surface of the movable knife.

In the buttonhole sewing machine according to claim 7, the concave portion is inclined downward along the side surface of the needle on the upper surface of the movable knife. In this case, the buttonhole sewing machine can more accurately guide the end of the upper thread toward the buttonhole stitch located below the upper thread holding mechanism.

In the buttonhole sewing machine according to claim 8, the above-mentioned upper thread holding mechanism has an auxiliary guide part provided on the side of the above-mentioned thread holding member opposite to the above-mentioned movable knife with the above-mentioned thread holding member interposed therebetween, and is connected to the above-mentioned The movable knife moves together, and when the thread cutting member is in the open state and exposed to the thread holding member, the auxiliary guide portion approaches the movable knife to cover the concave portion. In this case, the end of the needle thread released by the thread holding member is placed in a state where it can be guided by the recessed portion by the auxiliary guide portion. Therefore, the recess can more accurately guide the end of the upper thread toward the keyhole stitch.

Description of drawings

FIG. 1 is a side view showing the internal structure of a buttonhole sewing machine 1 .

FIG. 2 is a plan view showing the internal structure of the buttonhole sewing machine 1 .

FIG. 3 is a front view showing the internal structure of the buttonhole sewing machine 1. As shown in FIG.

FIG. 4 is a top view of the thread cutting member 30 and the connecting member 31 .

FIG. 5 is a plan view of the thread cutting member 30 and the presser foot 26 in a closed state.

FIG. 6 is a front view of the thread cutting member 30 and the presser foot 26 .

FIG. 7 is a top view of the thread cutting member 30 in an open state.

FIG. 8 is a plan view of the movable part 120 .

Fig. 9 is a cross-sectional view taken along the line AA shown in Fig. 8 .

FIG. 10 is a perspective view of the interlocking connection mechanism 50 .

FIG. 11 is a top view of keyhole stitch 95 .

Fig. 12 is a plan view of the thread cutting member 30 and the presser foot 26 at the sewing start position.

Fig. 13 is a side view of the thread cutting member 30 and the presser foot 26 at the sewing start position.

Figure 14 is a side view of the thread cutting member 30 and presser foot 26 after the first stitch has been formed.

Fig. 15 is a partially enlarged plan view of the thread cutting member 30 and the presser foot 26 in an opened state.

FIG. 16 is a cross-sectional view of the movable knife 125 shown in FIG. 15 along the line BB.

Fig. 17 is a plan view of the thread cutting member 30 and the presser foot 26 in the middle of sewing.

Fig. 18 is a side view of the thread cutting member 30 and the presser foot 26 in the middle of sewing.

Detailed ways

An embodiment of the buttonhole sewing machine 1 of the present invention will be described with reference to the drawings. The buttonhole sewing machine 1 is capable of forming buttonhole stitches on cloth. In Fig. 1, the near side is the right side of the buttonhole sewing machine 1, the back side is the left side of the buttonhole sewing machine 1, the upper side is the upper side of the buttonhole sewing machine 1, the lower side is the lower side of the buttonhole sewing machine 1, and the left side is the buttonhole sewing machine 1. The side is the front side of the buttonhole sewing machine 1 , and the right side is the rear side of the buttonhole sewing machine 1 . In Fig. 2, the front side is the upper side of the buttonhole sewing machine 1, the back side is the lower side of the buttonhole sewing machine 1, the upper side is the rear side of the buttonhole sewing machine 1, the lower side is the front side of the buttonhole sewing machine 1, and the left side The side is the left side of the buttonhole sewing machine 1, and the right side is the right side of the buttonhole sewing machine 1.

A schematic configuration of the buttonhole sewing machine 1 will be described with reference to FIGS. 1 to 3 . The keyhole sewing machine 1 includes a base part 10, a pillar part 11, an arm part 12, a needle bar up and down driving mechanism 14, a stitch forming mechanism 15, a cloth feeding mechanism 16, a presser foot lifting mechanism 17, an upper thread holding mechanism 18, a bobbin thread A cutting mechanism (not shown), a buttonhole forming mechanism (not shown), and an interlocking connection mechanism 50 . The pillar portion 11 is erected upward from the rear side of the base portion 10 . The arm portion 12 extends forward from the upper portion of the pillar portion 11 and faces the upper surface of the stand portion 10 .

The needle bar up and down driving mechanism 14 is used to drive the machine needle 21 and the needle bar 20 to make them move up and down. The stitch forming mechanism 15 is used to form keyhole stitches on cloth. The cloth feeding mechanism 16 cooperates with the presser foot 26 to feed the cloth in the front-rear direction. The presser foot lifting mechanism 17 is used to drive the presser foot 26 to make it lift. The upper thread holding mechanism 18 cuts the upper thread after sewing the buttonhole stitches, and holds an end of the cut upper thread (hereinafter referred to as an upper thread end). The needle thread holding mechanism 18 is located above the base portion 10 and behind the needle 21 . The bobbin thread cutting mechanism is used to cut the bobbin thread inside the frame portion 10 after sewing the buttonhole stitches. The buttonhole forming mechanism is used to form a buttonhole in the center of the buttonhole stitch. The interlocking connection mechanism 50 is used to connect the presser foot lifting mechanism 17, the upper thread holding mechanism 18, and the bobbin thread cutting mechanism to make them interlock.

The spindle 23 is provided inside the arm portion 12 in the front-rear direction. The rear end portion of the main shaft 23 protrudes rearward on the rear side of the pillar portion 11 . The hand wheel 22 is fixed to the rear end of the main shaft 23 . The timing belt 22 a is stretched between the hand wheel 22 and a drive pulley (not shown) provided on a drive shaft of a sewing machine motor (not shown). The driving force of the sewing machine motor is transmitted to the main shaft 23 via the timing belt 22a, and the main shaft 23 is rotated. The needle bar up and down driving mechanism 14 drives the needle bar 20 to move up and down along with the rotation of the main shaft 23 by means of a crank mechanism (not shown).

The stitch forming mechanism 15 includes a needle bar 20 , a needle 21 , and a thread take-up lever (not shown) provided on the arm part 12 , and a hook mechanism (not shown) provided on the base part 10 . The rotary hook mechanism has a rotary hook and a bobbin case in which a bobbin bobbin is accommodated. The sewing machine motor drives the needle bar 20 to make it move up and down by means of the main shaft 23 and the like. The needle bar 20 is equipped with an organic needle 21 at the lower end. The hook catches the upper thread supplied to the needle 21, and interlaces the upper thread with the lower thread fed out from the lower thread bobbin to form a buttonhole stitch.

The cloth feeding mechanism 16 has a cloth feeding member 24 and a cloth feeding motor (not shown), and feeds cloth in the forward and backward direction. The cloth feeding member 24 has a rectangular plate shape long in the front-rear direction. The base part 10 supports the cloth feeding member 24 so that the cloth feeding member 24 can move freely in the front-rear direction. The cloth feeding motor drives the cloth feeding member 24 to feed in the front-rear direction. The presser foot 26 is connected to the front end portion of the feed arm 27 and has a rectangular frame shape in plan view. The presser foot 26 presses the outer peripheral side portion of the stitch forming region of the buttonhole stitch from the upper side with respect to the feed member 24 .

The feed arm 27 is bent in a shape protruding upward, and extends in the front-rear direction. The rear end portion of the feed arm 27 reaches near the front end of the pillar portion 11 . The rear end portion of the feed arm 27 is connected to a movable body (not shown) that is connected to an upper portion of the feed member 24 so as to be rotatable about a support shaft extending in the left-right direction. The presser foot 26 moves back and forth integrally with the feed arm 27 in accordance with the feed movement of the feed member 24 in the front-rear direction, and moves up and down integrally with the front end portion of the feed arm 27 .

The presser foot lifting mechanism 17 has a connecting rod 28 extending vertically at the front end of the arm portion 12 . The lower end of the connecting rod 28 is connected to the upper end of the pressing arm 29 . The lower end portion of the pressing arm 29 is connected to the front end portion of the feed arm 27 and is relatively movable in the front-back direction with respect to the feed arm 27 . Drive the connecting rod 28 to make it move up and down by means of the interlocking connecting mechanism 50 . By driving the connecting rod 28 to move up and down, the front end of the cloth feeding arm 27 moves up and down together with the presser foot 26 via the presser arm 29 .

The configuration of the needle thread holding mechanism 18 will be described with reference to FIGS. 4 to 9 . In Fig. 4, the front side is the upper side of the buttonhole sewing machine 1, the back side is the lower side of the buttonhole sewing machine 1, the upper side is the rear side of the buttonhole sewing machine 1, the lower side is the front side of the buttonhole sewing machine 1, and the left side The side is the left side of the buttonhole sewing machine 1, and the right side is the right side of the buttonhole sewing machine 1. As shown in FIGS. 4 to 6 , the upper thread holding mechanism 18 has a thread cutting member 30 and a connecting member 31 . The thread cutting member 30 is in an open state when the keyhole stitch is sewn, and is switched from the open state to the closed state after the keyhole stitch is sewn. The connecting member 31 is a plate-like member extending in the front-rear direction. The front end portion of the connection member 31 is connected to the thread cutting member 30 . The support shaft 32 extends in the vertical direction, and supports the rear end portion of the connecting member 31 so that the connecting member 31 is rotatable and movable in the front-rear direction.

The upper thread holding mechanism 18 is capable of switching the thread cutting member 30 among four positions (cutting position, sewing start position, retreat position, and sewing middle position). The cutting position is a position where the thread cutting member 30 cuts the upper thread after sewing the buttonhole stitches, and is located near the needle 21 . The sewing start position is the position where the thread cutting member 30 moves before the keyhole stitch is to be sewn, and is located on the opposite side (rear) to the cloth feeding direction (front) at the start of sewing with respect to the cutting position. side) (see Figure 12). The sewing midway position is a position where the thread cutting member 30 is on standby during keyhole stitching, and is located on the left side of the sewing start position and behind the cutting position (see FIG. 17 ). The retracted position is a position where the thread cutting member 30 is retracted from the moving locus of the cloth cutting knife 48, and is located on the left side of the cutting position.

The structure of the thread cutting member 30 will be described. As shown in FIGS. 5 , 7 to 9 , the thread cutting member 30 has a fixed portion 100 , a plate portion 110 , a movable portion 120 , and an auxiliary guide portion 130 . The fixing portion 100 is a plate member extending substantially in the left-right direction. The left end portion of the fixing portion 100 is connected to the front end portion of the connection member 31 . The small-diameter restricting shaft 103 is erected substantially in the center of the right side plane portion of the fixing portion 100 . The fixed knife 105 (see FIG. 9 ) is provided on the right end front surface of the fixed part 100 .

The plate portion 110 has a horizontal flat plate shape extending substantially in the left-right direction, and is arranged above the portion of the fixing portion 100 on the side of the fixed blade 105 . The plate portion 110 has a guide hole 114 penetrating in the vertical direction. A pair of guide shafts 124 vertically disposed on the movable part 120 are arranged in the guide hole 114 . The guide hole 114 does not interfere with the pair of guide shafts 124, and has an arc shape in plan view. The restriction shaft 103 is connected to the left end edge portion of the plate portion 110 . The screw 102 vertically passes through a threaded hole (not shown) of the plate portion 110 on the slightly right side of the restricting shaft 103 to connect the plate portion 110 to the fixing portion 100 . Therefore, the plate part 110 cannot rotate relative to the fixed part 100 .

The movable part 120 has a substantially L-shaped horizontal plate shape, and is provided between the fixed blade 105 side part of the fixed part 100 and the plate part 110 . The movable part 120 has two openings (a threaded hole 122 and a restriction hole 123 ) penetrating in the vertical direction (see FIG. 8 ). The screw 102 vertically passes through the threaded hole 122 to rotatably connect the movable part 120 to the fixed part 100 . The limiting shaft 103 is disposed in the limiting hole 123 . Therefore, the movable part 120 is rotatable within a range (rotatable range) in which the restricting shaft 103 can relatively move within the restricting hole 123 around the screw 102 . A pair of guide shafts 124 protrudes upward from the upper surface of the movable part 120 and is movable in the guide hole 114 . The movable knife 125 is provided at the right end of the movable part 120 .

That is, the thread cutting member 30 has a pair of knives (the fixed knife 105 and the movable knife 125 ) for cutting the upper thread. The movable knife 125 is rotatable about a vertical axis (screw 102 ) relative to the fixed knife 105 . When the movable part 120 rotates counterclockwise in plan view, the movable knife 125 approaches the fixed knife 105 . In the closed state of the thread cutting member 30 shown in FIG. 5 , the fixed knife 105 and the movable knife 125 overlap up and down. When the movable part 120 rotates clockwise in plan view, the movable knife 125 moves away from the fixed knife 105 . In the open state of the thread cutting member 30 shown in FIG. 7 , the fixed knife 105 and the movable knife 125 do not overlap up and down. As described above, as the movable knife 125 rotates relative to the stationary knife 105, the thread cutting member 30 switches between the open state and the closed state. When the thread cutting member 30 is in the closed state, the movable knife 125 is opposite to the lower surface of the plate portion 110 , and when the thread cutting member 30 is in the open state, the movable knife 125 is away from the lower surface of the plate portion 110 .

The movable knife 125 has a knife edge part 126, a flat part 127, and a recessed part 128 (refer FIG. 9). The knife edge portion 126 is an end portion for cutting the noodle thread together with the fixed knife 105 , and the knife edge portion 126 is provided on the rear surface of the movable knife 125 facing the fixed knife 105 . The flat portion 127 is a horizontal upper surface of the movable knife 125 , and the flat portion 127 extends forward from the rear end of the blade tip portion 126 . When the thread cutting member 30 is in the closed state, the lower surface of the plate portion 110 can hold the end of the needle thread between it and the planar portion 127 .

The concave portion 128 has a first concave portion 128 a and a second concave portion 128 b continuously formed on the upper surface and the front surface of the movable knife 125 . The first concave portion 128 a is a groove extending in the front-rear direction on the upper surface of the movable knife 125 . The first concave portion 128 a is opposed to the lower surface of the plate portion 110 . The second recess 128b is a groove connected to the first recess 128a, and the second recess 128b extends in the vertical direction (vertical direction) on the front surface of the movable knife 125 on the needle 21 (see FIG. 5 ) side. Specifically, the first concave portion 128a extends from a substantially central portion in the front-rear direction of the upper surface of the movable knife 125 so as to incline downward toward the front side. The second recess 128b extends vertically from the front end of the first recess 128a, and extends from the upper end to the lower end of the front surface of the movable knife 125 .

The auxiliary guide part 130 is a linear spring (Japanese: 线バネ). One end of the auxiliary guide portion 130 is sandwiched between the upper side of the plate portion 110 and the screw 102 . The auxiliary guide portion 130 passes from the screw 102 between the pair of guide shafts 124 of the movable portion 120 , and extends toward the concave portion 128 of the movable knife 125 . Therefore, the auxiliary guide part 130 moves together with the pair of guide shafts 124 as the movable part 120 rotates. The other end of the auxiliary guide portion 130 is biased downward. Therefore, when the thread cutting member 30 is in the closed state, the other end side of the auxiliary guide portion 130 is in contact with the upper surface of the plate portion 110 (see FIG. 5 ). When the thread cutting member 30 is in the open state, the auxiliary guide 130 moves together with the guide shaft 124 , and the other end side of the auxiliary guide 130 contacts the upper surface of the movable knife 125 (see FIG. 7 ).

The upper thread holding mechanism 18 has a knife opening and closing mechanism 40 for opening/closing the fixed knife 105 and the movable knife 125 (see FIG. 5 ). The knife opening and closing mechanism 40 has a receiving part 41 , a first pushing part 42 and a second pushing part 43 . The receiving portion 41 is a protruding piece erected on the rear side edge of the movable portion 120 . The first pusher 42 is a plate-shaped protruding piece fixed to the left side of the feed arm 27 , and the right end portion of the first pusher 42 extends below the feed arm 27 . The right end portion of the pushing portion 42 is obliquely cut from the front toward the rear, and can be engaged with the left side surface of the receiving portion 41 . The second pusher 43 is a plate-shaped protruding piece fixed to the right side of the feed arm 27 , and the second pusher 43 extends downward of the feed arm 27 . The left side of the second pushing part 43 can engage with the right side of the receiving part 41 . The first pushing portion 42 engages with the receiving portion 41 as the feed arm 27 moves forward, and pushes the receiving portion 41 . When the first pushing part 42 pushes the receiving part 41 , the movable part 120 rotates clockwise relative to the fixed part 100 in a top view. That is, the movable knife 125 is switched to the open state. The second pushing part 43 engages with the receiving part 41 as the thread cutting member 30 moves to the right, and pushes the receiving part 41 . When the second pushing part 43 pushes the receiving part 41 , the movable part 120 rotates counterclockwise relative to the fixed part 100 in a plan view. That is, the movable knife 125 is switched to the closed state. Specifically, the knife opening and closing mechanism 40 closes the fixed knife 105 and the movable knife 125 when the upper thread holding mechanism 18 is in the cutting position or the sewing start position, and closes the fixed knife 105 and the movable knife 125 when the upper thread holding mechanism 18 is in the middle of sewing or in the withdrawn position. The fixed knife 105 and the movable knife 125 are opened.

The structure of the connecting member 31 will be described. As shown in FIGS. 4 to 6 , the elongated hole 31 a is a pair of upper and lower elongated holes long in the front-rear direction, and is formed in the rear end portion of the connection member 31 . A pair of upper and lower engaging members 39 (see FIG. 1 ) are slidably engaged with each elongated hole 31 a in a non-detachable manner. The engagement member 39 is connected to the lower portion of the support shaft 32 . A sewing machine frame (not shown) supports the upper portion of the support shaft 32 so that the support shaft 32 can rotate freely. Therefore, the coupling member 31 is capable of turning about the vertical axis and moving in the front-back direction.

The elongated hole 31 b is a rectangular shape long in the front-rear direction, and is formed at a position slightly forward of the center portion of the connection member 31 in the front-rear direction. The arc hole 31c is formed between the long holes 31a, 31b. The movable member 33 is provided at a substantially central portion in the front-rear direction of the coupling member 31 . The movable member 33 has a receiving portion 33b bent rightward from the front end and a first engagement portion 33c bent leftward from the rear end.

Most of the movable member 33 is provided on the left side of the connecting member 31 . Two screws 34 are fixed to the coupling member 31 and are slidably engaged in elongated holes 33 a formed in the movable member 33 and extending in the front-rear direction. Therefore, the movable member 33 can move back and forth relative to the connection member 31 .

The receiving part 33b penetrates the long hole 31b, and protrudes rightward. The movable member 33 can move back and forth with respect to the connecting member 31 by a distance corresponding to the approximate length of the elongated hole 31b. The spring attachment member 35 is provided on the connection member 31, and one end side of the tension spring 36 is connected. The other end side of the tension spring 36 is connected to the first engaging portion 33c. The tension spring 36 biases the movable member 33 rearward with respect to the connection member 31 .

The spring attachment member 37 is fixed to the upper end of the coupling member 31 on the front side of the central portion in the front-rear direction, and the spring attachment member 37 extends rightward. One end side of the tension spring 38 is connected to the right front end portion of the spring attachment member 37 . The other end side of the tension spring 38 is connected to the sewing machine frame on the left side of the connection member 31 . The tension spring 38 applies a force to the left to rotate the coupling member 31 around the support shaft 32 . The protrusion part 31f is formed in the upper end part of the connection member 31, and has a plate shape protruding leftward as a whole. The second engaging portion 31d is formed at the front of the protruding portion 31f. The step part 31e is provided in the front-back direction center part of the 2nd engaging part 31d, and protrudes partially to the left.

The first engaging receiving portion 45 is a plate-shaped member capable of engaging with the first engaging portion 33c. The second engagement receiving portion 46 is a roller engageable with the second engagement portion 31d. The first engagement receiving portion 45 and the second engagement receiving portion 46 are attached to a second link 66 (see FIGS. 1 and 10 ), which will be described later. When the first engaging portion 33c is engaged with the first engaging receiving portion 45, the thread cutting member 30 is held at the sewing start position. When the first engaging portion 33c is not engaged with the first engaging receiving portion 45, the thread cutting member 30 is allowed to be switched to the retracted position or the mid-sewing position. That is, the tension spring 38 urges the thread cutting member 30 toward the retracted position or the sewing midway position. On the other hand, when the second engaging portion 31d is engaged with the second engaging receiving portion 46, the thread cutting member 30 is held at any one of the retracted position, the cutting position, and the sewing midway position.

The configuration of the interlocking connection mechanism 50 will be described with reference to FIGS. 1 to 3 and 10 . The interlocking connection mechanism 50 has a lifting plate 52, a lifting rod 53, L-shaped connecting rods 54, 55, a linking plate 56, a first drive system 57, a second drive system 58, and the like.

The common motor 51 is horizontally provided at substantially the center in the vertical direction of the pillar portion 11 , and the axis of the common motor 51 extends in the left-right direction. The common motor 51 interlocks the presser foot lifting mechanism 17 , the upper thread holding mechanism 18 , and the bobbin thread cutting mechanism (not shown) via the interlocking connection mechanism 50 . A pair of guide shafts 52a extend in the vertical direction, and guide the lifting plate 52 so that the lifting plate 52 can be freely moved up and down. A gear 51 a fixed to an output shaft of the common motor 51 meshes with a rack 52 b formed on the lower end of the lift plate 52 . The elevating plate 52 has a bifurcated portion 52 c at the front upper end, and the bifurcated portion 52 c is engaged with an engaging shaft 53 a fixed to an upper end portion of the elevating rod 53 . The shared motor 51 drives the lifting rod 53 together with the lifting plate 52 to make it move up and down. The lower end portion of the lift lever 53 is connected to a lower thread cutting mechanism for cutting the lower thread.

A pair of L-shaped connecting rods 54 and 55 are respectively provided at the front and rear of the arm portion 12 . The sewing machine frame utilizes a support shaft 54a extending in the left-right direction to support the L-shaped link 54 in a rotatable manner, and a support shaft 55a extending in the left-right direction to make the L-shaped link 55 rotatable. The L-shaped link 55 is supported in a manner. The link plate 56 is a plate member long in the front-rear direction, and is provided between the L-shaped links 54 , 55 . The rear end portion of the link plate 56 is connected to the upper end portion of the L-shaped link 54 . The front end portion of the link plate 56 is connected to the upper end portion of the L-shaped link 55 .

The rear end portion of the L-shaped link 54 is rotatably connected to the upper end portion of the lift rod 53 . The front end portion of the L-shaped link 55 is connected to the upper end portion of the connecting rod 28 of the presser foot lifting mechanism 17 . When the elevating rod 53 is raised and lowered, the L-shaped connecting rods 54, 55 rotate, and the linkage plate 56 moves back and forth in the forward and backward direction while lifting slightly. When the link plate 56 moves forward, the presser foot 26 descends via the connecting rod 28 . When the interlocking plate 56 moves backward, the presser foot 26 rises via the connecting rod 28 .

The first driving system 57 transmits the reciprocating movement of the linkage plate 56 to the connecting member 31 in the forward and backward direction, thereby driving the connecting member 31 in the forward and backward direction. The first drive system 57 has a link member 60 and a first link 61 . The sewing machine frame supports the link member 60 so that the link member 60 can rotate about an axis extending in the left-right direction. The upper end portion of the first link 61 is fixed to the link member 60 . The link member 60 has an engaging shaft 60 a at its tip end, and the engaging shaft 60 a is engaged in a curved first guide hole 56 a formed in the link plate 56 . The lower end portion of the first link 61 has an engaging shaft 61 a, and the engaging shaft 61 a is engaged in the arc hole 31 c of the connecting member 31 .

The second drive system 58 transmits the reciprocating movement of the linkage plate 56 to the first engagement receiving portion 45 and the second engagement receiving portion 46, thereby driving the first engagement receiving portion 45 and the second engagement receiving portion 45 in the approximately front-rear direction. Engage the receiving part 46 . The second drive system 58 has a link member 65 and a second link 66 . The sewing machine frame supports the link member 65 so that the link member 65 can rotate about an axis extending in the left-right direction. The upper end portion of the second link 66 is fixed to the link member 65 . The engaging shaft 65 a at the tip end of the link member 65 is engaged in the curved second guide hole 56 b formed in the link plate 56 . The second link 66 is provided with a first engagement receiving portion 45 and a second engagement receiving portion 46 at a lower end thereof.

Referring to FIGS. 10 to 18 , an operation example in which the buttonhole sewing machine 1 sews the buttonhole stitch 95 (see FIG. 11 ) will be described. In the buttonhole sewing machine 1 before sewing starts, the linking plate 56 of the linking mechanism 50 is positioned substantially at the rear critical position. Therefore, the presser foot lifting mechanism 17 maintains the presser foot 26 in the lifted position. The thread cutting member 30 is located at the withdrawn position with the upper thread end portion 97 held. The operator places the cloth at the sewing position. The common motor 51 moves the interlocking plate 56 forward in response to an operator's operation of depressing a foot pedal (not shown).

During the movement of the interlocking plate 56 from the substantially rear critical position to the forward critical position, the presser foot 26 moves to the pressing position to completely press the cloth against the cloth feeding member 24 . While the interlocking plate 56 is moving from the rear critical position to the front critical position, the interlocking connection mechanism 50 uses the second drive system 58 to move the first engagement receiving portion 45 and the second engagement receiving portion 46 rearward. The second engaging receiving portion 46 is engaged with the stepped portion 31e of the second engaging portion 31d to press the coupling member 31 to the right. The thread cutting member 30 is moved rightward by the second engagement receiving portion 46 pushing the connection member 31 rightward.

When the linkage plate 56 moves further forward, the second drive system 58 moves the first engaging receiving portion 45 and the second engaging receiving portion 46 backward, and the first driving system 57 moves the connecting member 31 backward. move. As the coupling member 31 moves backward, the engagement between the stepped portion 31 e and the second engagement receiving portion 46 is released, and the first engagement portion 33 c engages with the first engagement receiving portion 45 . As shown in FIGS. 12 and 13 , the thread cutting member 30 is switched to the sewing start position. At this time, the presser foot 26 moves to the pressing position to press the cloth.

The buttonhole sewing machine 1 starts sewing the buttonhole stitch 95 from the state where the thread cutting member 30 is located at the sewing start position (see FIGS. 12 and 13 ). In this embodiment, the buttonhole forming mechanism (not shown) forms the buttonhole 95b on the cloth before the zigzag stitch 95a is sewn (see FIG. 11 ).

After the buttonhole 95b is formed, the buttonhole sewing machine 1 stops the operation of the interlocking connection mechanism 50 and performs sewing with the thread cutting member 30 positioned at the sewing start position. In other words, the needle 21 uses the thread cutting member 30 so that the end of the upper thread cut during the previous sewing operation (that is, the upper thread end 97 extending from the needle 21) is held backward and downward. The sewing operation starts in the state of the end of the

Immediately after the sewing of the keyhole stitch 95 is started, the pusher portion (not shown) of the feed arm 27 pushes the first engaging portion 33 c to move the movable member 33 forward. For example, when the sewing of the first stitch is completed, as shown in FIG. 14 , the thread cutting member 30 holds the upper thread end 97 extending rearward and upward. When each zigzag stitch 95a is formed needle by needle, the thread cutting member 30 holds the upper thread end 97 toward the rear and upward, and the needle 21 holds the upper thread end 97 Zigzag stitch 95a of keyhole stitch 95 is sewn in. In other words, the needle 21 sews the upper thread end 97 into the zigzag stitch 95 a while pulling out the upper thread end 97 from the thread cutting member 30 in accordance with the forward movement of the presser foot 26 .

As shown in FIGS. 15 and 16 , when the keyhole stitch 95 is to be sewn and the multi-needle zigzag stitch 95a is to be formed, the knife opening and closing mechanism 40 rotates the movable portion 120 clockwise in a plan view. The movable knife 125 is gradually separated from the fixed knife 105 and the plate portion 110 . When the movable knife 125 leaves the plate portion 110 , the tip of the auxiliary guide portion 130 moves from the plate portion 110 onto the movable knife 125 . In the thread cutting member 30, the auxiliary guide portion 130 replaces the plate portion 110 for holding the upper thread end portion 97 to prevent the upper thread end portion 97 from coming out of the first concave portion 128a above the first concave portion 128a. Therefore, the auxiliary guide portion 130 maintains the needle thread end portion 97 in a state where it can be guided by the concave portion 128 .

The needle 21 draws out the upper thread end 97 along the concave portion 128 . The needle thread end 97 moves from the movable knife 125 to the needle 21 side. At this time, the upper thread end 97 moves along the first concave portion 128a to the side (front side) opposite to the stitch formation direction, and then moves downward along the second concave portion 128b. That is, the upper thread end portion 97 moves toward the needle 21 side in a state extending straight to the rear side (feed direction) with respect to the zigzag stitch 95a. The needle 21 sews the pulled-out upper thread end 97 into the inside of the keyhole stitch 95 .

After the feed amount reaches a predetermined amount (for example, approximately 5 mm), the engagement between the first engaging portion 33 c and the first engaging receiving portion 45 is released. The connecting member 31 moves leftward under the biasing force of the tension spring 38 . The second engaging portion 31d is engaged with the second engaging receiving portion 46 . Therefore, as shown in FIGS. 17 and 18 , the thread cutting member 30 is switched to the middle position of sewing.

After the keyhole stitch 95 is formed, the link plate 56 starts to move backward from the state where the thread cutting member 30 is located at the middle position of sewing (see FIGS. 17 and 18 ). The second drive system 58 moves the first engagement receiving portion 45 and the second engagement receiving portion 46 forward, and the first drive system 57 moves the connection member 31 forward. The interlocking plate 56 further moves backward, and the interlocking connection mechanism 50 uses the second drive system 58 to move the first engagement receiving portion 45 and the second engagement receiving portion 46 forward. The second engaging receiving portion 46 is engaged with the stepped portion 31e of the second engaging portion 31d to switch the coupling member 31 to the disconnection position. The knife opening and closing mechanism 40 switches the thread cutting member 30 from the open state to the closed state, so that the fixed knife 105 and the movable knife 125 cut the upper thread. The plate portion 110 holds the cut needle thread end portion 97 between the plate portion 110 and the flat surface portion 127 .

At this time, the interlocking connection mechanism 50 interlocks the bobbin thread cutting mechanism (not shown) to cut the bobbin thread, and interlocks the presser foot lifting mechanism 17 to move the presser foot 26 to the raised position. The engagement between the second engagement receiving portion 46 and the stepped portion 31e of the second engagement portion 31d is released, whereby the connection member 31 is switched to the withdrawn position. Therefore, the buttonhole sewing machine 1 returns to the original state described first in this description of the operation. That is, it is in a state where the cloth can be taken out when the sewing of the buttonhole stitch 95 is completed. In addition, the buttonhole forming mechanism may form the buttonhole 95b in the middle of sewing the zigzag stitch 95a or after the zigzag stitch 95a is sewn instead of forming the buttonhole 95b before sewing the zigzag stitch 95a.

As described above, the buttonhole sewing machine 1 of the present embodiment includes: the cloth feeding mechanism 16 for feeding the cloth on the bed 10; and the upper thread holding mechanism 18, which is used to cut the upper thread and hold the upper thread end after sewing the buttonhole stitch. The upper thread holding mechanism 18 includes: a thread cutting member 30, which can be switched between an open state and a closed state; and a plate portion 110, which is used to hold the end of the cut upper thread on the plate portion when the thread cutting member 30 is in the closed state. 110 and the thread cutting member 30; and a recess 128 for guiding the end of the upper thread that has been released by the plate portion 110 toward the keyhole stitch when the thread cutting member 30 is in the open state. When the thread cutting member 30 is switched from the closed state to the open state after starting to sew the keyhole stitch, the end of the upper thread that has been released by the plate portion 110 is guided to the keyhole stitch by the concave portion 128 . Therefore, the buttonhole sewing machine 1 can accurately sew the end of the upper thread into the buttonhole stitch.

The thread cutting member 30 has a fixed knife 105 and a movable knife 125 . The concave portion 128 is provided on the movable knife 125 and extends toward the keyhole stitch sewed by the needle 21 . Therefore, the recessed part 128 can be provided in a narrow place with a simple structure.

The recessed portion 128 has a first recessed portion 128 a provided on the side of the movable knife 125 opposite to the side facing the fixed knife 105 . Therefore, the recess 128 can accurately guide the end of the needle thread toward the keyhole stitch located below the needle thread holding mechanism 18 along the recess formed on the upper surface of the movable knife 125 .

The concave portion 128 has a first concave portion 128a provided on the planar portion 127 of the movable knife 125 and a second concave portion 128b provided on the side surface of the movable knife 125 on the needle 21 side. Therefore, the concave portion 128 can accurately guide the end of the upper thread toward the keyhole stitch located below the upper surface and the side surface of the movable knife 125 along the concave portion continuously formed on the upper surface and the side surface of the movable knife 125 .

The needle thread holding mechanism 18 has an auxiliary guide portion 130 for holding the end of the needle thread cut by the thread cutting member 30 in a state capable of being guided by the concave portion 128 when the thread cutting member 30 is in the open state. The end of the needle thread released by the plate portion 110 is placed in a state where it can be guided by the recessed portion 128 by the auxiliary guide portion 130 . Therefore, the recessed portion 128 can more accurately guide the end of the upper thread toward the keyhole stitch.

In the said embodiment, the cloth feeding mechanism 16 is corresponded to the "transfer mechanism" of this invention. The stitch forming mechanism 15 corresponds to the "sewing mechanism" of the present invention. The plate portion 110 corresponds to the "wire holding member" of the present invention. The 1st recessed part 128a and the 2nd recessed part 128b correspond to the "recessed part" of this invention.

The present invention is not limited to the above-mentioned embodiment, and various changes can be made. For example, the recessed portion 128 may be a recessed portion as long as it can guide the end of the upper thread released by the plate portion 110 toward the keyhole stitch when the thread cutting member 30 is in the open state. Accordingly, the recess 128 may also be a groove or notch extending toward the keyhole stitch when the thread cutting member 30 is in the open state.

The concave portion 128 only needs to be provided on the opposite side of the movable knife 125 to the side opposite to the fixed knife 105 (the front surface of the movable knife 125) and the flat surface 127 (the front surface of the movable knife 125) on which the end of the upper thread can be placed. on at least one of the upper surfaces). In other words, the concave portion 128 only needs to have one of the first concave portion 128a and the second concave portion 128b.

The auxiliary guide portion 130 is not limited to a linear spring, and may be a shape in which a portion near the recess 128 is bent toward the recess 128 , or may be a leaf spring, for example. In order to simplify the structure of the buttonhole sewing machine 1, the auxiliary guide 130 may not be provided. In this case, the plate portion 110 may not have the guide hole 114 , and the movable portion 120 may not have the pair of guide shafts 124 .

Claims (8)

1. A keyhole sewing machine (1), comprising: A conveying mechanism (16), which is used to convey the cloth placed on the machine base (10) in a predetermined direction; a sewing mechanism (15) that sews keyhole stitches on the cloth conveyed by the conveying mechanism by moving the needle (21) supplied with the upper thread up and down; and The upper thread holding mechanism (18) is arranged above the above-mentioned base part, and is arranged on the upstream side of the above-mentioned machine needle in the direction in which the above-mentioned conveying mechanism conveys the cloth when the above-mentioned keyhole stitch is started to be sewn, and is used for the above-mentioned After sewing the above-mentioned keyhole stitches, the sewing mechanism cuts the above-mentioned upper thread and holds the end of the cut above-mentioned upper thread, that is, holds the end of the upper thread (97). The keyhole sewing machine is characterized in that The above-mentioned upper thread holding mechanism includes: a thread cutting member (30), which is a pair of knives which are in an open state when the above-mentioned keyhole stitch is being sewn, and which are switched from the above-mentioned open state to The closed state thus cuts off the upper thread; a thread holding member (110), which is provided on the thread cutting member, and is used for holding the cut end of the upper thread between the thread holding member and the thread cutting member when the thread cutting member is in the closed state; a knife opening and closing mechanism (40) for switching said thread cutting member from said closed state to said open state after said keyhole stitching is started; and a concave portion (128) provided on the thread cutting member for guiding toward the keyhole stitch sewn by the needle when the knife opening and closing mechanism switches the thread cutting member to the open state by the thread holding member The end of the upper thread after letting go. the 2. The buttonhole sewing machine according to claim 1, characterized in that, The thread cutting member has a fixed knife (105) and a movable knife (125), the movable knife is overlapped with the fixed knife, and the movable knife can move on the needle side of the fixed knife so as to be in the open state and the fixed knife with the fixed knife. To switch between the above closed states, The above-mentioned wire holding member is opposite to the above-mentioned movable knife on the side opposite to the above-mentioned fixed knife across the above-mentioned movable knife, The recess is provided on a side surface of the movable knife on the side of the needle. the 3. The buttonhole sewing machine according to claim 2, characterized in that, The recess extends from an upper end to a lower end on a side surface of the movable knife on the needle side. the 4. The buttonhole sewing machine according to claim 1, characterized in that, The thread cutting member has a fixed knife (105) and a movable knife (125), the movable knife is overlapped with the fixed knife, and the movable knife can move on the needle side of the fixed knife so as to be in the open state and the fixed knife with the fixed knife. To switch between the above closed states, The wire holding member is opposed to the movable knife on the opposite side of the movable knife to the fixed knife across the movable knife, The concave portion is continuously provided on a side surface of the movable knife on the needle side and an upper surface of the movable knife opposed to the thread holding member. the 5. The buttonhole sewing machine according to claim 4, characterized in that, The concave portion is inclined downward along the needle-side side surface of the movable knife on the upper surface of the movable knife, and extends from an upper end to a lower end on the needle-side side surface of the movable knife. the 6. The buttonhole sewing machine according to claim 1, characterized in that, The above-mentioned thread cutting member has a fixed knife (105) and a movable knife (125), and the movable knife is movable on the needle side relative to the above-mentioned fixed knife so as to be between the above-mentioned open state and the above-mentioned closed state with respect to the above-mentioned fixed knife. transition between states, The above-mentioned wire holding member is opposite to the above-mentioned movable knife on the side opposite to the above-mentioned fixed knife with respect to the above-mentioned movable knife, The recess is provided on an upper surface of the movable knife opposite to the wire holding member. the 7. The buttonhole sewing machine according to claim 6, characterized in that, The concave portion is inclined downward along the side surface of the needle on the upper surface of the movable knife. the 8. The buttonhole sewing machine according to any one of claims 2 to 7, characterized in that, The above-mentioned upper thread holding mechanism has an auxiliary guide part (130), which is provided on the opposite side of the above-mentioned thread holding member to the above-mentioned movable knife across the above-mentioned thread holding member, and moves together with the above-mentioned movable knife, When the thread cutting member is in the open state and exposed to the thread holding member, the auxiliary guide portion approaches the movable knife to cover the concave portion. the

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