JP2017080315A - Thread cutting mechanism and sewing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thread cutting mechanism and a sewing machine which can shorten cut ends of a needle thread and a bobbin thread left on a sewing object after being cut.SOLUTION: When sewing is ended, a transmission member 130 moves forward and rotates a driving blade 120 counterclockwise in a bottom surface view to arrange it at a preparation position. A grooved cam 150 guides a roller member 165 of a driven blade 110 to a rear end part 152 and arranges the driven blade 110 at a separate position where a blade part 114 is separated from a needle hole 9A. When the transmission member 130 moves rearward, the grooved cam 150 guides the roller member 165 to an intermediate part 153 and arranges the driven blade 110 at an approach position where the blade part 114 is positioned at a needle hole 9A formation position. The driving blade 120 rotates clockwise in the bottom surface view and moves to a cutting position where a blade part 124 is positioned at the needle hole 9A formation position. The blade part 124 and the blade part 114 cross each other and cut a needle thread and a bobbin thread at the formation position of the needle hole 9A.SELECTED DRAWING: Figure 7

Description

  The present invention relates to a thread cutting mechanism and a sewing machine for cutting a thread after completion of sewing.

  The sewing machine drives the thread trimming mechanism after the end of sewing and cuts the upper thread and the lower thread. The thread trimming mechanism of a sewing machine described in Patent Document 1 includes a fixed blade and a movable blade. The fixed blade is fixed to the lower surface of the needle plate, and the blade tip is arranged on the side of the needle hole. The movable blade is placed below the fixed blade and attached to the needle plate so as to be rotatable with a step screw. The movable blade is connected to a pulse motor. At the time of thread trimming, the sewing machine drives a pulse motor to rotate the movable blade around the step screw. The movable blade captures the upper thread and the lower thread and cuts them by sandwiching them between the fixed blade.

  The thread trimming mechanism cuts an upper thread and a lower thread formed on the cloth on the needle plate at the lower side of the needle plate. Therefore, the upper thread and the lower thread after cutting leave a cut end corresponding to the length of the path from the stitch formation position on the cloth back side to the cutting edge of the fixed blade through the needle hole.

JP 2006-314514 A

  There is a desire to shorten the upper and lower thread ends that remain on the fabric after cutting. However, since the fixed blade of the thread cutting mechanism is fixed to the lower surface of the needle plate and the cutting edge is disposed on the side of the needle hole, there is a distance from the cutting edge to the needle hole. Therefore, the upper end and lower end of the thread remaining on the cloth are relatively long. When fixing the fixed blade to the needle plate with the blade tip closer to the needle hole than the above thread trimming mechanism to reduce the distance from the blade tip to the needle hole, the lower thread may touch the fixed blade during sewing and break the thread. was there. Therefore, the fixed blade could not be brought close to the needle hole, and it was difficult to shorten the upper thread and lower thread cut ends remaining on the cloth.

  An object of the present invention is to provide a thread trimming mechanism and a sewing machine that can shorten the upper ends of upper and lower threads remaining on a sewing object after cutting.

  According to the first aspect of the present invention, a first blade provided on the lower side of a needle plate having a needle hole through which a sewing needle passes, a position provided on the lower side of the needle plate so as to be rotatable, and a position away from the needle hole From the needle hole on the opposite side of the standby position to the cutting position, the cutting position where the cutting edge intersects the cutting edge of the first blade at the needle hole forming position, A second blade movable between a preparation position for disposing the cutting edge at a distant position, a driving force of a power source is transmitted to the second blade, and the second blade is moved between the standby position and the preparation position. And the second blade moves from the standby position to the preparation position via the transmission member by driving the power source, and then moves from the preparation position to the cutting position. When the second blade moves from the preparation position to the cutting position, the upper thread and the lower thread are captured. In the thread trimmer mechanism that cuts in cooperation with the first blade, the first blade has an approach position where the blade tip is disposed at the formation position of the needle hole and a spaced position separated from the needle hole with respect to the approach position. A moving mechanism for moving the first blade between the approaching position and the separating position, and operating with the driving force of the power source together with the transmission member. When not driven, the first blade is located at the separation position, and the second blade is located at the standby position.When the power source is driven, the transmission member causes the second blade to move from the preparation position. When moving to the cutting position, the moving mechanism moves the first blade from the separated position to the approach position, and a thread cutting mechanism is provided.

  At the time of sewing, the first blade and the second blade are arranged with their cutting edges away from the needle holes. Since the upper thread and the lower thread are less likely to contact the blade edge, the thread trimming mechanism can reduce the possibility of thread breakage. At the time of thread trimming, the first blade and the second blade intersect the cutting edge at the formation position of the needle hole and cut the upper thread and the lower thread. Therefore, the thread trimming mechanism can shorten the upper thread and lower thread cut ends remaining on the sewing object as compared with the case where the upper thread and the lower thread are cut at a position away from the needle hole.

  In the first aspect, when the power source is driven, the transmission member reciprocates in a predetermined direction parallel to a horizontal direction to reciprocate the second blade between the standby position and the preparation position, A moving mechanism provided integrally with the transmission member, having a bent portion bent in a direction intersecting the predetermined direction and extending in a groove shape along the predetermined direction; provided on the first blade; and A roller member fitted to the groove cam, and when the second blade is positioned at the standby position or the preparation position by movement of the transmission member, the roller member is positioned at an end of the groove cam. When the first blade is disposed at the separated position and the second blade is disposed at the cutting position, the roller member is disposed at the bent portion of the groove cam and the first blade is disposed at the approach position. May be.

  The moving mechanism is a groove cam and a roller member. Since the roller member is fitted to the groove cam, the roller member is not separated from the cam surface. That is, no force is required to press the roller member against the cam surface in order to maintain the engagement between the cam surface and the roller member. Therefore, since the moving mechanism has a configuration that does not require an urging member, for example, the number of parts can be reduced.

  In the first aspect, the first blade and the second blade have a flat plate shape, are provided on the needle plate, and the first blade and the second blade are coaxially arranged in an axial direction and can be rotated respectively. When the transmission member reciprocates in the predetermined direction, the rotation locus of the cutting edge of the second blade that rotates about the shaft portion by the transmission member is caused by the movement mechanism. Including a position that overlaps the rotation trajectory of the cutting edge of the first blade that rotates, and when the first blade is positioned at the approach position and the second blade is positioned at the cutting position, the cutting edge of the second blade May intersect the cutting edge of the first blade.

  A single shaft is sufficient to support the first blade and the second blade in a rotatable manner. Therefore, the thread trimming mechanism can reduce the number of parts.

  In the first aspect, a shaft portion that is provided on the needle plate and rotatably supports the second blade, and a first urging member that urges the first blade from the approach position toward the separation position. The moving mechanism is provided so as to be rotatable together with the second blade about the shaft portion, and extends in a circumferential direction facing a radially outer side of the shaft portion, and the circumferential direction of the cam surface An outer peripheral cam having a protrusion projecting outward in the radial direction at a part thereof, a roller member capable of rolling along the cam surface of the outer peripheral cam, and a shaft provided on the needle plate is rotatable. And a link member that connects the first blade to the other end, the first biasing member via the link member, and the roller member on the cam surface. When the power source is driven, the transmission member moves back and forth in a predetermined direction parallel to the horizontal direction. When the second blade is reciprocated between the standby position and the preparation position, and the second blade is positioned at the standby position or the preparation position by the movement of the transmission member, the roller member moves toward the cam surface. When the first blade is disposed at the separated position in contact with a portion other than the inner protrusion, and the second blade is positioned at the cutting position, the roller member contacts the inner protrusion of the cam surface. The first blade may be disposed in contact with the approaching position.

  The moving mechanism is an outer peripheral cam and a roller member. The outer peripheral cam is easy to form and has high durability. Therefore, the thread trimming mechanism can operate reliably over a long period of time.

  In the first aspect, the moving mechanism includes a second urging member that urges the roller member to one side in the axial direction of the shaft portion, and the protrusion is one side in the axial direction of the cam surface. And a surface facing toward the other side in the axial direction forms an inclined surface that is inclined from one side in the axial direction toward the other side toward the other end side in the circumferential direction of the shaft portion, When the blade moves from the standby position to the preparation position, the roller member moves the other axial side of the protrusion along the inclined surface from one end side to the other end side in the circumferential direction of the shaft portion. When the second blade moves from the preparation position to the cutting position when the first blade is moved and arranged at the separated position by the bias of the first biasing member, the roller member moves to the shaft portion. Moving along the protrusion from the other end side in the circumferential direction toward the one end side through the link member The serial first blade may be moved to the approaching position from the spaced position.

  The cam surface that guides the roller member when the second blade moves from the standby position to the preparation position does not include a protrusion. Since the roller member does not contact the protrusion, the first blade is maintained at the separated position. Therefore, the thread cutting mechanism can prevent the cutting edge of the first blade from coming into contact with the upper thread and the lower thread before cutting the upper thread and the lower thread at the cutting position.

  In the first aspect, the needle plate includes a guide portion that linearly guides the movement of the first blade, and the link member has a length that engages with a pin provided on the first blade at the other end. The pin has a hole, and the pin moves in the range of the elongated hole by the rotation of the link member, and the first blade is converted into power that moves linearly between the separation position and the approach position. May be.

  Since the first blade moves linearly, when cutting the upper thread and the lower thread, the angle of the blade edge directed toward the second blade can be kept constant. Therefore, the thread trimming mechanism can perform stable thread trimming.

  In the first aspect, the outer circumferential cam has a hole extending in the circumferential direction of the shaft portion, and the second blade has a fixing member that integrally fixes the second blade and the outer circumferential cam, The outer peripheral cam may be fixed by the fixing member by changing a fixing position with respect to the second blade within the range of the hole.

  The position where the second blade meshes with the first blade during thread trimming can be adjusted by adjusting the positional relationship with the outer peripheral cam in accordance with the position of the fixing member in the hole.

  The first aspect includes a first biasing member that biases the first blade from the approach position toward the separation position, and a shaft portion that is provided on the needle plate and rotatably supports the second blade. The moving mechanism is provided on the second blade and protrudes outward in the radial direction of the shaft portion, and rotates about a roller member that operates together with the transmission member and an upstream support shaft provided on the needle plate. A possible upstream rotating member, and a downstream rotating member rotatable about a downstream support shaft provided on the needle plate, the upstream rotating member being radially outward of the upstream support shaft. A roller protrusion that protrudes and is capable of contacting the roller member; and an action protrusion that protrudes radially outward in a direction different from the roller protrusion. The other end is connected to the first blade, and the second blade is moved from the standby position to the preparation position. When moving to the position, the action protrusion presses the roller protrusion in a direction away from the one end of the downstream rotating member, and the first blade is moved to the separated position by the bias of the first biasing member. When the second blade moves from the preparation position to the cutting position, the action protrusion presses the roller protrusion in a direction to contact the one end of the downstream rotating member, The blade may move from the separated position to the approach position via the action protrusion and the downstream rotating member.

  When the second blade moves from the preparation position to the cutting position, even if the roller member rotates the upstream rotation member, the action protrusion does not contact the downstream rotation member. Therefore, the downstream rotating member does not rotate, and the first blade is maintained at the separated position. Therefore, the thread cutting mechanism can prevent the cutting edge of the first blade from coming into contact with the upper thread and the lower thread before cutting the upper thread and the lower thread at the cutting position.

  In the first aspect, the needle plate includes a guide portion that linearly guides the movement of the first blade, and the moving mechanism linearly moves the first blade between the separation position and the approach position. You may move on.

  Since the first blade moves linearly, when cutting the upper thread and the lower thread, the angle of the blade edge directed toward the second blade can be kept constant. Therefore, the thread trimming mechanism can perform stable thread trimming.

  In the first aspect, the downstream rotation member is rotatable about the downstream support shaft, the first member extending between the one end portion and the downstream support shaft, and the downstream support shaft. A second member that is rotatable and extends between the other end portion and the downstream support shaft, wherein the first member is an elongated hole between the one end portion and the downstream support shaft. The second member has an assembly member that engages with the adjustment hole and is assembled to the first member, and the downstream rotation member is assembled within the range of the adjustment hole. It may be possible to assemble the first member and the second member by changing the assembly position of the member.

  The downstream rotating member adjusts the positional relationship between the first member and the second member in accordance with the position of the assembly member within the adjustment hole, so that the position where the first blade and the second blade mesh with each other during thread trimming. Can be adjusted.

  According to the second aspect of the present invention, the first blade provided on the lower side of the needle plate having a needle hole through which the sewing needle passes, and the position provided at the lower side of the needle plate so as to be rotatable and away from the needle hole. From the needle hole on the opposite side of the standby position to the cutting position, the cutting position where the cutting edge intersects the cutting edge of the first blade at the needle hole forming position, A second blade movable between a preparation position for disposing the cutting edge at a distant position, a driving force of a power source is transmitted to the second blade, and the second blade is moved between the standby position and the preparation position. And the second blade moves from the standby position to the preparation position via the transmission member by driving the power source, and then moves from the preparation position to the cutting position. When the second blade moves from the preparation position to the cutting position, the upper thread and the lower thread are captured. In the sewing machine provided with a thread cutting mechanism that cuts in cooperation with the first blade, the first blade has an approach position where the blade tip is disposed at the formation position of the needle hole and the approach position from the needle hole. The thread cutting mechanism is movable with the transmission member and the driving force of the power source to move the first blade between the approach position and the separation position. The first blade is located at the separation position and the second blade is located at the standby position when the power source is not driven, and the transmission member is used when the power source is driven. When the second blade moves from the preparation position to the cutting position, the moving mechanism moves the first blade from the separated position to the approach position.

  At the time of sewing, the first blade and the second blade are arranged with their cutting edges away from the needle holes. Since the upper thread and the lower thread are less likely to contact the blade edge, the thread trimming mechanism can reduce the possibility of thread breakage. At the time of thread trimming, the first blade and the second blade intersect the cutting edge at the formation position of the needle hole and cut the upper thread and the lower thread. Therefore, the sewing machine can shorten the upper thread and lower thread cut ends remaining on the sewing object as compared with the case where the upper thread and the lower thread are cut away from the needle hole.

1 is a perspective view of a sewing machine 1. FIG. 2 is a right side view of the sewing machine 1. FIG. 2 is a rear view of the sewing machine 1. FIG. It is a bottom view of the thread trimming mechanism 100 when the driving blade 120 is in the standby position. 3 is a perspective view of a needle plate 9 and a drive mechanism 15. FIG. It is a bottom view of the thread trimming mechanism 100 when the driving blade 120 is in the preparation position. It is a bottom view of the thread trimming mechanism 100 when the driving blade 120 is in the cutting position. It is a bottom view of the thread trimming mechanism 200 when the driving blade 220 is in the standby position. 5 is a perspective view of a cam member 270. FIG. It is the side view of the cam member 270 seen in the arrow A direction of FIG. It is a bottom view of the thread trimming mechanism 200 when the driving blade 220 moves from the standby position to the preparation position. It is a bottom view of the thread trimming mechanism 200 when the driving blade 220 is in the preparation position. It is a bottom view of the thread trimming mechanism 200 when the driving blade 220 is in the cutting position. It is a bottom view of the thread trimming mechanism 300 when the driving blade 320 is in the standby position. It is a bottom view of the thread trimming mechanism 300 when the driving blade 320 moves from the standby position to the preparation position. It is a bottom view of the thread trimming mechanism 300 when the driving blade 320 is in the preparation position. It is a bottom view of the thread trimming mechanism 300 when the driving blade 320 is in the cutting position.

  A first embodiment of the present invention will be described. In the following description, left, right, front, back, and top and bottom indicated by arrows in the figure are used.

  The overall structure of the sewing machine 1 will be described. As shown in FIGS. 1 to 3, the sewing machine 1 is a tacking sewing machine that forms tacking stitches on a cloth. The sewing machine 1 includes a bed portion 2, a pedestal column portion 3, and an arm portion 4. The bed portion 2 extends in the front-rear direction, and includes a vertical shuttle 8, a feed base (not shown), a cloth feed mechanism (not shown), and the like. The bed unit 2 includes a needle plate 9. The needle plate 9 has a needle hole 9A (see FIG. 5) on the upper surface of the front end portion. The feed plate 11 is located on the needle plate 9 and is fixed to the feed base.

  The pedestal 3 extends upward from the rear side of the bed 2 and includes a sewing machine motor 91 on the back wall. The arm portion 4 extends forward from the upper end of the pillar portion 3 substantially parallel to the bed portion 2 and includes a main shaft that is driven by a sewing machine motor 91 inside. The front end portion 5 of the arm portion 4 projects downward from other portions of the arm portion 4. The front end portion 5 supports the needle bar 6 so as to be movable up and down. The needle bar 6 extends downward from the lower end of the front end portion 5. The sewing needle 7 is detachably attached to the lower end of the needle bar 6 and is driven in the vertical direction together with the needle bar 6 by driving the main shaft.

  The sewing machine 1 is provided with a presser foot device 10 at the top of the bed portion 2. The presser foot device 10 includes a presser foot 12. The presser foot 12 is positioned above the needle plate 9. The presser foot device 10 raises and lowers the presser foot 12 and presses the cloth as a sewing object from above. The presser foot device 10 is driven by a presser foot motor (not shown). The presser foot motor is provided inside the pedestal 3.

  The cloth feed mechanism includes an X feed motor (not shown) and a Y feed motor (not shown). The cloth feed mechanism drives the X feed motor and the Y feed motor to move the cloth presser device 10, the feed plate 11, and the feed base in the X direction (left-right direction) and the Y direction (front-back direction). The sewing machine 1 feeds the cloth in the X direction and the Y direction in accordance with the vertical movement of the sewing needle 7, and forms a tack seam on the cloth.

  As shown in FIG. 4, the sewing machine 1 includes a thread trimming mechanism 100 and a thread gripping mechanism 40 on the lower surface side of the needle plate 9. The thread trimming mechanism 100 performs an upper thread and lower thread cutting operation at the end of the sewing operation. The thread gripping mechanism 40 bends and holds the upper thread that has passed below the cloth at the first stitch at the start of sewing, and prevents the thread from coming out of the sewing needle 7. As shown in FIGS. 1 to 3, the sewing machine 1 fixes a thread trimming motor 95 to the back side of the bed portion 2 via a bracket 80. The thread trimming motor 95 is a pulse motor and is a drive source for the thread trimming mechanism 100 and the thread gripping mechanism 40.

  In the following description, the direction of each member constituting the thread trimming mechanism 100 will be described in the direction when the driving blade 120 is positioned at the standby position (see FIG. 4). As shown in FIG. 4, the thread cutting mechanism 100 includes a driven blade 110, a driving blade 120, a transmission member 130, and a moving mechanism 160. The driven blade 110 is a substantially L-shaped plate material as viewed from the bottom, with one end 111 extending leftward and the other end 112 extending diagonally forward right. The driven blade 110 has a shaft hole (not shown) in an L-shaped bent portion. The shaft hole engages with the support shaft 9B. The support shaft 9B is provided on the lower surface of the needle plate 9, and supports the driven blade 110 so as to be horizontally reciprocally rotatable. The driven blade 110 includes a blade portion 114. The blade portion 114 is formed in a portion protruding rearward from the one end portion 111. The distance between the support shaft 9B and the blade portion 114 is substantially the same as the distance between the support shaft 9B and the formation position of the needle hole 9A. When the driven blade 110 rotates, the blade portion 114 moves along an arc-shaped locus centering on the support shaft 9B. The movement trajectory of the blade portion 114 includes the formation position of the needle hole 9A. The driven blade 110 includes a cylindrical roller member 165. The roller member 165 is provided at the other end 112 and protrudes downward.

  The shape of the driving blade 120 is a plate shape extending in the left-right direction. The drive blade 120 has a shaft hole (not shown) that engages with the support shaft 9B in an intermediate portion. The support shaft 9B supports the drive blade 120 so as to be horizontally reciprocally rotatable. That is, the support shaft 9B supports the driven blade 110 and the driving blade 120 so as to be rotatable coaxially. The driving blade 120 is disposed below the driven blade 110. An annular washer 107 is disposed between the driven blade 110 and the driving blade 120. The washer 107 engages with the support shaft 9B. The gap between the blade portion 114 of the driven blade 110 and the blade portion 124 of the driving blade 120 can be adjusted by arranging a washer 107 or a plurality of washers 107 having different thicknesses.

  The driving blade 120 includes one end 121 and the other end 122. One end 121 extends to the left of the shaft hole, and the other end 122 extends to the right of the shaft hole. The one end portion 121 includes a threading portion 123, a blade portion 124, a thread engaging portion 125, a yarn guiding portion 126, and a yarn catching portion 127. The threading portion 123 is a portion that enters the upper thread ring (not shown) of the upper thread formed by the sewing needle 7 below the needle plate 9 at the time of sewing. The blade portion 124 is an end portion of a through hole that penetrates the drive blade 120 in the vertical direction. The distance between the support shaft 9B and the blade portion 124 is substantially the same as the distance between the support shaft 9B and the formation position of the needle hole 9A. When the driving blade 120 rotates, the blade portion 124 moves along an arcuate locus centering on the support shaft 9B. The movement locus of the blade portion 124 passes through the formation position of the needle hole 9A. The thread engaging portion 125 is a portion that hooks the side of the upper thread ring that extends from the sewing needle 7. The yarn guide portion 126 is a portion that is curved between the yarn winding portion 123 and the yarn catching portion 127, and guides the side of the upper thread ring that extends from the cloth to the yarn catching portion 127. The thread catcher 127 is a part that catches the upper thread ring. The other end 122 includes a pin 119 protruding downward. The pin 119 is rotatably connected to the distal end portion 131 of the transmission member 130.

  The shape of the transmission member 130 is a plate shape that extends long in the front-rear direction. The distal end portion 131 of the transmission member 130 has a portion that is bent in an arc shape to the right. The tip 131 has a through hole 133 that penetrates in the vertical direction. The pin 119 of the driving blade 120 engages with the through hole 133. During operation of the thread trimmer mechanism 100, the transmission member 130 reciprocates in the front-rear direction. At this time, the through-hole 133 reciprocates in an arc shape centering on the support shaft 9B between the diagonally right rear and the right diagonal front of the support shaft 9B. The bent portion of the tip portion 131 is positioned to the right of the support shaft 9B when moving forward, and avoids contact between the tip portion 131 and the support shaft 9B.

  The transmission member 130 has a cam portion 170 at the distal end portion 131. The cam portion 170 is formed in a substantially rectangular plate shape in plan view, and is integrally provided in front of the tip portion 131. The cam portion 170 has a groove cam 150 penetrating in the vertical direction. The groove cam 150 extends in the front-rear direction, and an intermediate portion 153 between the front end portion 151 and the rear end portion 152 is bent leftward. The roller member 165 is fitted into the groove cam 150. The roller member 165 and the groove cam 150 constitute a moving mechanism 160. The moving mechanism 160 converts the power that the transmission member 130 moves in the front-rear direction into the power that the driven blade 110 rotates between the separated position and the approach position. During the operation of the thread cutting mechanism 100, the cam portion 170 reciprocates in the front-rear direction diagonally to the right of the support shaft 9B. The roller member 165 moves along an arc-shaped locus centering on the support shaft 9B along the shape of the groove cam 150.

  The thread gripping mechanism 40 includes a thread gripping plate 41 and a holding plate 44. The shape of the thread gripping plate 41 is a substantially L-shaped plate whose central portion is bent at a substantially right angle. One end 41A of the thread gripping plate 41 extends forward from the bent portion, and the other end 41B extends leftward from the bent portion. The support shaft 42 is fixed to the lower surface of the needle plate 9 and rotatably supports the center portion of the thread gripping plate 41. One end 41A includes a hole 41C and a pin 41E. The hole 41C penetrates the thread gripping plate 41 in the vertical direction. The pin 41E is provided on the rear side of the hole 41C and protrudes upward. The other end 41 </ b> B is connected to the other end 63 </ b> B of the third link 63 by a pin 48. The third link 63 extends forward from the thread clamp link mechanism 60 (see FIG. 5). When the third link 63 moves in the front-rear direction, the thread gripping plate 41 reciprocates horizontally around the support shaft 42.

  The shape of the holding plate 44 is a substantially L-shaped plate whose central portion is bent at a substantially right angle. One end 44A of the holding plate 44 extends forward from the bent portion, and the other end 41B extends rightward from the bent portion. The support shaft 47 is fixed to the lower surface of the needle plate 9 and supports the central portion of the holding plate 44 so as to be rotatable. The one end 44A is bent rightward and bent downward. The holding plate 44 is disposed on the upper side of the thread gripping plate 41. One end portion 44 </ b> A of the holding plate 44 is arranged to face one end portion 41 </ b> A of the thread gripping plate 41. The tension spring 45 urges the other end 44 </ b> B rearward to rotate the holding plate 44 about the support shaft 47 in the clockwise direction when viewed from the bottom. The pin 41E of the thread gripping plate 41 abuts on the right side surface of the one end portion 44A of the holding plate 44 and restricts the rotation of the holding plate 44.

  The sewing machine 1 includes a drive mechanism 15 in the bed portion 2. The drive mechanism 15 drives the thread trimming mechanism 100 and the thread gripping mechanism 40. As shown in FIG. 5, the drive mechanism 15 includes a thread trimming motor 95, a cam plate 70, a thread trimming link mechanism 50, and a thread gripping link mechanism 60. The thread trimming motor 95 is fixed to the lower back surface of the bed 2 (see FIG. 1) via a bracket 80. The bracket 80 is formed in a substantially U-shaped groove shape in rear view. The bracket 80 is fixed with three screws 84 (see FIG. 3) with the opening side facing rightward and the lower back of the bed portion 2. The thread trimming motor 95 is fixed to the upper surface of the bracket 85, and an output shaft (not shown) is disposed in the bracket 85. The cam plate 70 is disposed in the bracket 85 and connected to the output shaft of the thread cutting motor 95. The cam plate 70 forms a groove cam (not shown) on the top surface and forms an outer peripheral cam (not shown) on the side surface. The groove cam converts the rotational force of the output shaft into power for driving the yarn cutting link mechanism 50. The outer peripheral cam converts the rotational force of the output shaft into power for driving the thread gripping link mechanism 60.

  The thread trimming link mechanism 50 includes a first link 51 and a second link 52 in order from the thread trimming motor 95 side toward the thread trimming mechanism 100 side. The shape of the first link 51 is a substantially L-shaped plate whose central portion is bent at a substantially right angle. The bracket 80 supports the central portion of the first link 51 so as to be horizontally rotatable. One end 51 </ b> A of the first link 51 protrudes to the right of the bracket 80. One end 51 </ b> A is rotatably connected to the other end 52 </ b> B of the second link 52 via a pin 56. The other end (not shown) of the first link 51 includes a roller member (not shown) protruding downward. The roller member is fitted into the groove cam of the cam plate 70.

  The second link 52 extends inside the bed portion 2 through the hole portion 2A (see FIG. 1). The hole 2A is provided on the right side of the lower back of the bed 2. The second link 52 bends in some places according to the structure in the bed portion 2 and extends forward. One end 52 </ b> A of the second link 52 is fixed to the base end 132 of the transmission member 130 with two screws 57. The transmission member 130 extends forward substantially linearly from the base end portion 132 toward the thread trimming mechanism 100. The tip 131 of the transmission member 130 is rotatably connected to the driving blade 120 via a pin 119. When the thread trimmer motor 95 is driven, the thread trimmer link mechanism 50 drives the driving blade 120 and the driven blade 110 of the thread trimmer mechanism 100 according to the rotation direction and angle of the cam plate 70 to cut the upper thread and the lower thread. To do. Details of operations of the thread trimmer link mechanism 50 and the thread trimmer mechanism 100 will be described later.

  The thread gripping link mechanism 60 includes a first link (not shown), a second link 62, and a third link 63 in order from the thread trimming motor 95 side toward the thread gripping mechanism 40 side. The first link of the thread gripping link mechanism 60 is formed in a substantially linear shape in plan view, and is disposed below the first link 51 of the thread trimming link mechanism 50. The bracket 80 supports the central part of the first link so as to be coaxial with the first link 51 of the thread trimming link mechanism 50 and horizontally rotatable. One end portion of the first link protrudes to the left of the bracket 80 and is rotatably connected to the other end portion of the second link 62. The other end of the first link includes a roller member (not shown) protruding downward. The roller member comes into contact with the outer peripheral cam of the cam plate 70. The second link 62 extends into the bed part 2 through a hole (not shown) provided on the left side of the lower part of the back of the bed part 2. The second link 62 bends in some places according to the structure in the bed 2 and extends forward. One end portion 62 </ b> A of the second link 62 is fixed to the other end portion 63 </ b> B of the third link 63 with two screws 67. The third link 63 bends in some places according to the structure in the bed portion 2 and extends forward toward the thread gripping mechanism 40. One end 63A of the third link 63 is rotatably connected to the thread gripping plate 41 via a pin 48 (see FIG. 4).

  The operation of the thread trimming mechanism 100 and the thread gripping mechanism 40 will be described. At the start of sewing, the thread trimmer motor 95 drives the output shaft to reciprocate the cam plate 70 in a predetermined direction. The thread gripping link mechanism 60 rotates the thread gripping plate 41 and the holding plate 44 of the thread gripping mechanism 40 according to the rotation direction and angle of the cam plate 70. As shown in FIG. 4, when the third link 63 moves forward, the thread gripping plate 41 rotates clockwise as viewed from the bottom. The hole 41C of the one end 41A is located below the needle hole 9A.

  The upper thread of the first stitch at the start of sewing passes through the cloth and extends downward from the needle hole 9A of the needle plate 9 through the hole 41C of the thread gripping plate 41. The thread trimming motor 95 moves the third link 63 rearward and rotates the thread gripping plate 41 counterclockwise as viewed from the bottom. The upper thread passing through the hole 41C moves to the left together with the one end 41A of the thread gripping plate 41. The one end portion 41A sandwiches the upper thread with the one end portion 44A of the holding plate 44, and bends and holds the upper thread. From the first stitch onward, the one end 41A of the thread gripping plate 41 continues to move to the left and presses the holding plate 44 with the pin 41E of the one end 41A. The upper thread comes out from between the thread gripping plate 41 and the holding plate 44 and also comes out from the hole 41C. The sewing machine 1 continues sewing by winding the first held upper thread into the seam. When the output shaft returns to the state before the start of sewing, the thread trimmer motor 95 stops driving and enters a non-driven state.

  At the end of sewing, the thread trimming motor 95 drives the output shaft and reciprocates the cam plate 70 in the direction opposite to that at the start of sewing. The thread trimming link mechanism 50 is driven according to the rotation direction and angle of the cam plate 70, and reciprocates the transmission member 130 of the thread trimming mechanism 100 in the front-rear direction. As shown in FIGS. 4, 6, and 7, when the transmission member 130 reciprocates in the front-rear direction, the driving blade 120 reciprocates horizontally around the support shaft 9 </ b> B via the pin 119, and is in a standby position. (See FIG. 4) and reciprocating between the preparation position (see FIG. 6). The standby position is a drive when the one end 121 of the drive blade 120 does not overlap the formation position of the needle hole 9A of the needle plate 9 and the blade 124 is disposed at a front position away from the formation position of the needle hole 9A. This is the position of the blade 120. When the driving blade 120 is positioned at the standby position, the transmission member 130 is positioned most rearward in the range of movement in the front-rear direction. The thread cutting mechanism 100 arranges the driving blade 120 at the standby position except during thread cutting. The preparation position is a position where the blade portion 124 passes through the formation position of the needle hole 9A and the one end portion 121 does not overlap the formation position of the needle hole 9A when the driving blade 120 rotates counterclockwise from the standby position. This is the position of the driving blade 120 when. When the driving blade 120 is located at the preparation position, the transmission member 130 is located at the foremost position in the range of movement in the front-rear direction.

  The roller member 165 of the driven blade 110 is positioned diagonally to the right of the support shaft 9B and is fitted to the groove cam 150 of the cam portion 170. The front end portion 151 and the rear end portion 152 of the groove cam 150 are located at the right end of the cam portion 170, and the intermediate portion 153 is located at the left end of the cam portion 170. Therefore, when the transmission member 130 moves to one side in the front-rear direction, the roller member 165 reciprocates in the left-right direction along the groove cam 150. As the roller member 165 reciprocates in the left-right direction, the driven blade 110 reciprocates horizontally around the support shaft 9B, and reciprocates between the separation position (see FIG. 4) and the approach position (see FIG. 7). Moving. The separation position is the position of the driven blade 110 when the one end portion 111 of the driven blade 110 does not overlap the formation position of the needle hole 9A and the blade portion 114 is arranged at a front position away from the formation position of the needle hole 9A. It is. The approach position is the position of the driven blade 110 when the blade portion 114 is disposed at the formation position of the needle hole 9A. The driving blade 120 and the driven blade 110 rotate around the same support shaft 9B. The movement locus of the blade portion 124 of the driving blade 120 includes a position overlapping the movement locus of the blade portion 114 of the driven blade 110.

  When the driving blade 120 is in the standby position, the roller member 165 is positioned at the front end portion 151 of the groove cam 150. At this time, the roller member 165 is positioned at the right end of the moving range in the left-right direction, and the driven blade 110 is positioned at the separated position (see FIG. 4). When the transmission member 130 moves forward by driving the thread cutting motor 95, the driving blade 120 rotates counterclockwise as viewed from the bottom, and moves from the standby position toward the preparation position. When the driving blade 120 moves from the standby position toward the preparation position, the threading portion 123 of the driving blade 120 passes through the formation position of the needle hole 9A. The threading portion 123 enters the upper thread ring formed by the sewing needle 7 below the needle plate 9. At this time, the side of the upper thread ring extending from the sewing needle 7 is engaged with the thread engaging portion 125. The thread engaging portion 125 moves rearward with the upper thread hooked, and guides the upper thread ring extending from the sewing needle 7 rearward. When the driving blade 120 is located at the preparation position, the side of the upper thread ring that extends from the sewing needle 7 contacts the thread engaging portion 125 and extends upward through the needle hole 9A.

  When the driving blade 120 moves from the standby position toward the preparation position, the roller member 165 passes through the intermediate portion 153 on the way from the front end portion 151 to the rear end portion 152 of the groove cam 150. When the roller member 165 passes through the intermediate portion 153, the roller member 165 is located at the left end of the moving range in the left-right direction. At this time, the driven blade 110 is located at the approach position. The driving blade 120 is positioned so as to cover the driven blade 110 from below in the process of moving from the standby position to the preparation position. The drive blade 120 allows the side of the upper thread ring extending from the sewing needle 7 to escape to the right side of the blade portion 114 of the driven blade 110 at the thread engaging portion 125. The driving blade 120 allows the side of the upper thread ring extending from the cloth and the lower thread to escape to the left side of the blade portion 114 of the driven blade 110 through the yarn guide portion 126. When the driving blade 120 moves to the preparation position, the roller member 165 is positioned at the rear end portion 152 of the groove cam 150. At this time, the roller member 165 is located at the right end of the moving range in the left-right direction, and the driven blade 110 is located at the separated position (see FIG. 6).

  When the transmission member 130 moves rearward by driving the thread cutting motor 95, the driving blade 120 rotates clockwise as viewed from the bottom, and moves from the preparation position toward the standby position. In the process in which the driving blade 120 moves from the preparation position to the standby position, the yarn catching portion 127 guides the side of the upper yarn ring that extends from the cloth and the lower yarn to the center of the yarn catching portion 127. The side of the upper thread ring that extends from the cloth and the lower thread extend from the thread catching section 127 toward the blade section 124 along a recess (not shown) provided on the upper surface of the one end section 121.

  When the driving blade 120 moves from the preparation position toward the standby position, the roller member 165 passes through the intermediate portion 153 on the way from the rear end portion 152 to the front end portion 151 of the groove cam 150. When the roller member 165 passes through the intermediate portion 153, the driven blade 110 is located at the approach position. While the driven blade 110 is located at the approach position, the blade portion 124 of the drive blade 120 passes through the formation position of the needle hole 9A from the rear toward the front. The blade portion 124 of the driving blade 120 intersects the blade portion 114 of the driven blade 110 in the vertical direction when passing through the formation position of the needle hole 9A. The position of the driving blade 120 at this time is a cutting position. That is, the cutting position is the position of the driving blade 120 when the driven blade 110 is in the approach position and the blade portion 124 of the driving blade 120 intersects the blade portion 114 of the driven blade 110. When the driving blade 120 passes through the cutting position in the process of moving from the preparation position to the standby position, the groove cam 150 of the cam portion 170 guides the roller member 165 to the intermediate portion 153 and places the driven blade 110 in the approach position ( (See FIG. 7). The blade portion 124 of the driving blade 120 and the blade portion 114 of the driven blade 110 sandwich the side of the upper thread ring that extends toward the cloth and the lower thread, and cut each.

  The transmission member 130 moves rearward by driving the thread cutting motor 95, and the driving blade 120 moves from the cutting position to the standby position (see FIG. 4). The groove cam 150 of the cam portion 170 guides the roller member 165 to the front end portion 151 by the rearward movement of the transmission member 130. The roller member 165 is located at the right end of the moving range in the left-right direction. The driven blade 110 moves to the separation position, and the yarn cutting mechanism 100 finishes cutting the yarn.

  The sewing machine 1 can drive the driven blade 110 via the moving mechanism 160 by driving the thread cutting link mechanism 50 and driving the driving blade 120. That is, the sewing machine 1 does not need to provide a drive mechanism for driving the driven blade 110 in addition to the thread cutting link mechanism 50. Therefore, the sewing machine 1 can be assembled with the thread cutting mechanism 100 only by replacing the conventional thread cutting mechanism using a fixed blade instead of the driven blade 110.

  As described above, in the first embodiment, at the time of sewing, the driven blade 110 and the driving blade 120 arrange the respective blade portions 114 and 124 at positions away from the needle hole 9A. Since the upper thread and the lower thread are difficult to contact the blade portions 114 and 124, the thread cutting mechanism 100 can reduce the possibility of thread breakage. At the time of thread trimming, the driven blade 110 and the driving blade 120 intersect the blade portions 114 and 124 at the formation position of the needle hole 9A to cut the upper thread and the lower thread. Therefore, the thread trimming mechanism 100 can shorten the upper thread and lower thread cut ends remaining on the sewing object as compared with the case where the upper thread and the lower thread are cut at a position away from the needle hole 9A.

  The groove cam 150 and the roller member 165 formed on the cam portion 170 constitute a moving mechanism 160. Since the roller member 165 is fitted into the groove cam 150, the roller member 165 does not leave the cam surface. That is, in order to maintain the engagement between the cam and the roller, no force is required to press the roller member 165 against the cam surface. Therefore, since the moving mechanism 160 does not require an urging member, for example, the number of parts can be reduced.

  A single supporting shaft 9B that supports the driven blade 110 and the driving blade 120 in a rotatable manner is sufficient. Therefore, the thread trimming mechanism 100 can reduce the number of parts.

  A second embodiment of the present invention will be described with reference to FIGS. The sewing machine 1 according to the second embodiment is different in the configuration of the thread trimmer mechanism 200 from the configuration of the thread trimmer mechanism 100 of the first embodiment. Since the other configuration of the sewing machine 1 is the same, the configuration of the thread trimming mechanism 200 will be described below, and the description of the other configurations will be omitted. In the following description, the direction of each member constituting the thread trimming mechanism 200 will be described in the direction when the driving blade 220 is positioned at the standby position (see FIG. 8).

  As shown in FIG. 8, the thread cutting mechanism 200 includes a driven blade 210, a driving blade 220, a transmission member 230, and a moving mechanism 260. The driven blade 210 is plate-shaped and extends obliquely leftward from the one end 211 toward the other end 212. The one end 211 side is formed narrower than the other end 212 side. The driven blade 210 is provided with a blade portion 214 at one end portion 211 and a pin 213 at the other end portion 212. The pin 213 protrudes downward. The needle plate 9 includes a guide portion 201 on the lower surface. The guide part 201 forms the needle hole 9 </ b> A in a groove shape extending linearly along the driven blade 210. The groove width of the guide portion 201 is substantially the same as the plate width of the driven blade 210. The driven blade 210 engages with the guide portion 201 and is arranged with one end portion 211 facing the needle hole 9A. The holding plate 204 having a U-shape when viewed from the bottom is provided along a part of the right end, the left end, and the rear end of the guide portion 201. The holding plate 204 holds the edge of the driven blade 210 from the lower side, and holds the driven blade 210 so as to be linearly movable in the guide portion 201. The presser plate 204 is fixed to the needle plate 9 with screws 261. The screw 261 abuts on the left end 241 of the link member 240 and restricts the movement of the driven blade 210 obliquely forward to the left.

  The driven blade 210 moves linearly between the separated position and the approach position by the guidance of the guide unit 201. The separation position is the position of the driven blade 210 when the blade portion 214 is arranged at a position that is diagonally left forward of the needle hole 9A. The approach position is the position of the driven blade 210 when the blade portion 214 is disposed at the formation position of the needle hole 9A. The throat plate 9 includes a pin 202 that protrudes downward and obliquely to the left of the guide portion 201. The tension spring 206 is hooked between the pin 213 of the driven blade 210 and the pin 202 of the needle plate 9. The tension spring 206 urges the driven blade 210 diagonally forward to the left.

  The link member 240 has a plate shape extending in the left-right direction, and an intermediate portion is bent. The left end 241 of the link member 240 extends rearward from the bent portion. A right end 242 of the link member 240 extends rightward from the bent portion. The link member 240 has a shaft hole (not shown) at the bent portion. The shaft hole engages with the support shaft 203. The support shaft 203 is provided on the lower surface of the needle plate 9 and is positioned obliquely forward and to the right of the guide portion 201. The support shaft 203 supports the link member 240 so as to be horizontally reciprocable. The left end 241 has a long hole 243 along the direction in which the left end 241 extends. The pin 213 of the driven blade 210 engages with the long hole 243 of the link member 240 and can move within the long hole 243. The right end 242 includes a roller member 265 that protrudes downward. A compression spring 245 that engages with the support shaft 9B is provided between the needle plate 9 and the link member 240. The compression spring 245 biases the link member 240 downward.

  As described above, when the tension spring 206 urges the driven blade 210 obliquely to the left, the pin 213 engages with the elongated hole 243, so that the link member 240 causes the support shaft 203 to be moved by the urging of the tension spring 206. It rotates in the clockwise direction when viewed from the bottom. The roller member 265 moves rearward by the rotation of the link member 240. Therefore, the roller member 265 can maintain a state in which the roller member 265 is in contact with the outer peripheral cam 250 by the urging of the tension spring 206.

  The shape of the driving blade 220 is a plate shape extending in the left-right direction. The driving blade 220 has a shaft hole (not shown) that engages with the support shaft 9B at an intermediate portion. The support shaft 9B supports the drive blade 220 so as to be horizontally reciprocally rotatable. The driving blade 220 includes one end 221 and the other end 222. One end 221 extends to the left of the shaft hole, and the other end 222 extends to the right of the shaft hole. The one end 221 includes a threading portion 223, a blade portion 224, a thread engaging portion 225, a yarn guiding portion 226, and a yarn catching portion 227. The configurations of the threading unit 223, the blade unit 224, the thread engaging unit 225, the thread guiding unit 226, and the thread catching unit 227 are the same as the threading unit 123, the blade unit 124, the thread engaging unit 125, and the thread guide of the first embodiment. Since it is the same as that of the part 126 and the thread | yarn capture part 127, description is abbreviate | omitted. The other end portion 222 includes a pin 219 protruding downward. The pin 219 engages with the through hole 233 of the distal end portion 231 of the transmission member 230. The driving blade 220 is rotatably connected to the transmission member 230. The drive blade 220 has a protrusion 228 that protrudes in front of the shaft hole. The protrusion 228 includes a bolt 229 that protrudes downward.

  The cam member 270 is provided below the drive blade 220. As shown in FIGS. 9 and 10, the cam member 270 includes an outer peripheral cam 250 and a support plate 275. The support plate 275 has a shaft hole 276 that engages with the support shaft 9B. The support plate 275 protrudes in a plate shape obliquely leftward and rearward from the left diagonally rear end of the outer cam 250. The outer circumferential cam 250 has cam surfaces 251 to 253 with which the roller member 265 abuts and a protrusion 254. The link member 240, the roller member 265, and the outer peripheral cam 250 constitute a moving mechanism 260. The moving mechanism 260 converts the power that the transmission member 230 moves in the front-rear direction into the power that the driven blade 210 moves between the separated position and the approach position.

  The cam surfaces 251 to 253 are arc-shaped outer peripheral surfaces with the shaft center of the shaft hole 276 as the center, and extend in front of the shaft hole 276 in the circumferential direction. The protrusion 254 is provided at a position on the left side of the center in the circumferential direction of the cam surfaces 251 to 253 and a position on the lower side of the center in the vertical direction. The protrusion 254 protrudes radially outward from the cam surfaces 251 to 253. The cam surface 251 is located on the left side of the protrusion 254. The cam surface 252 is located above the protrusion 254. The cam surface 253 is located on the right side of the protrusion 254. When the roller member 265 comes into contact with the cam surfaces 251 to 253, the driven blade 210 is located at the separated position.

  The thickness of the protrusion 254 in the vertical direction is larger on the cam surface 253 side than on the cam surface 251 side. The upper surface of the protrusion 254 forms an inclined surface 255 that is inclined upward from the cam surface 251 side toward the cam surface 253 side. When the roller member 265 contacts the outer peripheral surface 256 of the protrusion 254, the driven blade 210 is located at the approach position. The cam member 270 has a long hole 257 that penetrates in the vertical direction and extends in the circumferential direction on the radially inner side of the cam surfaces 251 to 253. When the support shaft 9B is engaged with the shaft hole 276 of the support plate 275, the bolt 229 of the protrusion 228 of the drive blade 220 is engaged with the elongated hole 257. The cam member 270 and the driving blade 220 can shift the positions of the bolts 229 horizontally by moving the position of the bolt 229 within the range of the elongated hole 257. As shown in FIG. 8, the nut 205 is fastened to the bolt 229 to fix the drive blade 220 and the cam member 270. Therefore, the cam member 270 and the drive blade 220 rotate integrally around the support shaft 9B. By adjusting the positional relationship between the cam member 270 and the driving blade 220, the timing at which the roller member 265 contacts the protrusion 254 changes. That is, the thread cutting mechanism 200 can shift the timing at which the moving mechanism 260 operates the driven blade 210. Therefore, the thread cutting mechanism 200 can adjust the position where the blade part 224 of the driving blade 220 and the blade part 214 of the driven blade 210 intersect when cutting the upper thread and the lower thread.

  The shape of the transmission member 230 is a plate shape that extends long in the front-rear direction. The distal end portion 231 of the transmission member 230 has a portion bent in an arc shape to the right. The tip 231 has a through hole 233 that penetrates in the vertical direction. The pin 219 of the driving blade 220 engages with the through hole 233. During the operation of the thread trimming mechanism 200, the transmission member 230 reciprocates in the front-rear direction. At this time, the through hole 233 reciprocates in an arc shape centering on the support shaft 9B between the diagonally right rear and the diagonally right front of the support shaft 9B. The bent portion of the tip 231 is positioned to the right of the support shaft 9B when moving forward, and avoids contact between the tip 231 and the support shaft 9B.

  The operation of the thread trimming mechanism 200 will be described. At the end of sewing, the thread trimming motor 95 drives the output shaft. The thread trimming link mechanism 50 is driven according to the rotation direction and angle of the cam plate 70, and reciprocates the transmission member 230 of the thread trimming mechanism 200 in the front-rear direction. As shown in FIGS. 8 to 13, when the transmission member 230 reciprocates in the front-rear direction, the driving blade 220 reciprocates horizontally around the support shaft 9 </ b> B via the pin 219, and is in a standby position (FIG. 8). And a reciprocating movement between the preparation position (see FIG. 12). When the driving blade 220 is positioned at the standby position, the transmission member 230 is positioned most rearward in the range of movement in the front-rear direction. The thread cutting mechanism 200 arranges the driving blade 220 at the standby position except during thread cutting. When the driving blade 220 is positioned at the preparation position, the transmission member 230 is positioned most forward in the range of movement in the front-rear direction. When the driving blade 220 moves between the standby position and the preparation position, the blade portion 224 moves along an arcuate rotation locus centering on the support shaft 9B. At this time, the blade portion 224 passes through the formation position of the needle hole 9A.

  When the driving blade 220 is in the standby position, the roller member 265 contacts the cam surface 251 of the outer cam 250 by the biasing force of the tension spring 206. At this time, the driven blade 210 is located at the separated position. A compression spring 245 that biases the link member 240 moves the roller member 265 downward. The lower end of the roller member 265 is positioned above the upper end of the protrusion 254 at the end of the protrusion 254 on the cam surface 251 side.

  When the transmission member 230 moves forward by driving the thread trimmer motor 95, the driving blade 220 rotates counterclockwise as viewed from the bottom, and moves from the standby position toward the preparation position. As shown in FIG. 11, when the driving blade 220 moves from the standby position toward the preparation position, the roller member 265 moves from the cam surface 251 to the cam surface 252. Since the roller member 265 has a lower end positioned above the upper end of the protrusion 254 at the end of the protrusion 254 on the cam surface 251 side, the roller member 265 contacts the inclined surface 255 of the protrusion 254 and moves upward along the inclined surface 255. (Refer to the one-dot chain line in FIG. 10). Therefore, the roller member 265 does not contact the outer peripheral surface 256 of the protrusion 254 but contacts the cam surface 252. Since the cam surfaces 251 to 253 extend in the circumferential direction of the support shaft 9B, even if the roller member 265 moves from the cam surface 251 to the cam surface 252, the position in the front-rear direction does not change. Therefore, the link member 240 does not rotate and maintains the driven blade 210 in the separated position.

  By the rotation of the driving blade 220, the threading portion 223 passes through the formation position of the needle hole 9A. The threading portion 223 enters the upper thread ring formed by the sewing needle 7 below the needle plate 9. At this time, the side of the upper thread ring extending from the sewing needle 7 is engaged with the thread engaging portion 225. The thread engaging portion 225 moves rearward with the upper thread hooked, and guides the upper thread ring extending from the sewing needle 7 rearward. When the driving blade 220 is located at the preparation position, the side of the upper thread ring that extends from the sewing needle 7 contacts the thread engaging portion 225 and extends upward through the needle hole 9A. Since the driven blade 210 maintains the position at the separated position, the drive blade 220 and the driven blade 210 form the needle portion 224 and the blade portion 214 forms the needle hole 9A in the process of moving the drive blade 220 from the standby position to the preparation position. Does not overlap in position.

  As the drive blade 220 rotates, the roller member 265 moves from the cam surface 252 to the cam surface 253. When the roller member 265 moves away from the position where the protrusion 254 is formed, the compression spring 245 urges the link member 240 to move the roller member 265 downward. The lower end of the roller member 265 is located below the upper end of the protrusion 254 at the end of the protrusion 254 on the cam surface 253 side (see the broken line in FIG. 10). As shown in FIG. 12, when the driving blade 220 moves to the preparation position, the roller member 265 is positioned on the cam surface 253. Since the cam surfaces 251 to 253 extend in the circumferential direction of the support shaft 9B, even if the roller member 265 moves from the cam surface 252 to the cam surface 253, the position does not change. The link member 240 does not rotate and maintains the driven blade 210 in the separated position.

  When the transmission member 230 moves rearward by driving the thread cutting motor 95, the driving blade 220 rotates clockwise as viewed from the bottom, and moves from the preparation position toward the standby position. In the process in which the driving blade 220 moves from the preparation position to the standby position, the yarn catcher 227 guides the upper thread ring on the side extending from the cloth and the lower thread to the center of the yarn catcher 227. The side of the upper thread ring that extends from the cloth and the lower thread extend from the thread catcher 227 toward the blade 224 along a recess (not shown) provided on the upper surface of the one end 221.

  When the driving blade 220 moves from the preparation position toward the standby position, the roller member 265 has a lower end positioned on the cam surface 253 side end of the protrusion 254 below the upper end of the protrusion 254. It moves from the surface 253 to the outer peripheral surface 256 of the protrusion 254 (see the two-dot chain line in FIG. 10). As shown in FIG. 13, the protrusion 254 presses the roller member 265 forward. The link member 240 rotates counterclockwise when viewed from the bottom. The link member 240 presses the pin 213 engaged with the elongated hole 243 backward. The pin 213 and the long hole 243 convert the rotation of the link member 240 into a linear movement of the driven blade 210. The driven blade 210 moves diagonally right rearward along the guide part 201 and is located at the approach position. While the driven blade 210 is located at the approach position, the blade portion 224 of the drive blade 220 passes through the formation position of the needle hole 9A from the rear toward the front. The blade portion 224 intersects the blade portion 214 of the driven blade 210 in the vertical direction when passing through the formation position of the needle hole 9A. The position of the driving blade 220 at this time is a cutting position. The blade portion 224 of the driving blade 220 and the blade portion 214 of the driven blade 210 sandwich the side of the upper thread ring that extends toward the cloth and the lower thread, and cut each.

  The transmission member 230 moves rearward by driving the thread cutting motor 95, and the drive blade 220 moves from the cutting position to the standby position. As shown in FIG. 8, the roller member 265 moves from the outer peripheral surface 256 of the protrusion 254 to the cam surface 251 by the rearward movement of the transmission member 230. When the roller member 265 moves to the cam surface 251, the link member 240 rotates counterclockwise as viewed from the bottom by the biasing force of the tension spring 206. The driven blade 210 moves diagonally to the left forward by the urging force of the tension spring 206 and moves to the separated position. The yarn cutting mechanism 200 ends the yarn cutting.

  The sewing machine 1 can drive the driven blade 210 via the moving mechanism 260 by driving the thread cutting link mechanism 50 and driving the driving blade 220. That is, the sewing machine 1 does not need to provide a drive mechanism for driving the driven blade 210 in addition to the thread cutting link mechanism 50. Therefore, the sewing machine 1 can be assembled with the thread trimming mechanism 200 only by replacing the conventional thread trimming mechanism using a fixed blade instead of the driven blade 210.

  As described above, in the second embodiment, the moving mechanism 260 is the outer peripheral cam 250 and the roller member 265. The outer peripheral cam 250 is easy to form and has high durability. Therefore, the thread trimming mechanism 200 can operate reliably over a long period of time.

  When the driving blade 220 moves from the standby position to the preparation position, the cam surfaces 251 to 253 that guide the roller member 265 do not include the protrusion 254. Since the roller member 265 does not come into contact with the protrusion 254, the driven blade 210 is maintained at the separated position. Therefore, the thread cutting mechanism 200 can prevent the blade portion 214 of the driven blade 210 from coming into contact with and cutting the upper thread and the lower thread before the driving blade 220 cuts the upper thread and the lower thread at the cutting position.

  Since the driven blade 210 moves linearly along the guide portion 201, the angle of the blade portion 224 directed toward the driving blade 220 can be kept constant when the upper thread and the lower thread are cut. Therefore, the thread trimming mechanism 200 can perform stable thread trimming.

  The driving blade 220 can adjust the position where the driving blade 220 meshes with the driven blade 210 during thread trimming by adjusting the positional relationship with the outer peripheral cam 250 according to the position of the bolt 229 in the elongated hole 257.

  A third embodiment of the present invention will be described with reference to FIGS. The sewing machine 1 according to the third embodiment is different in the configuration of the yarn cutting mechanism 300 from the configuration of the yarn cutting mechanism 100 of the first embodiment. Since the other configurations of the sewing machine 1 are the same, the configuration of the thread trimming mechanism 300 will be described below, and the description of the other configurations will be omitted. In the following description, the direction of each member constituting the yarn cutting mechanism 300 will be described in the direction when the driving blade 320 is positioned at the standby position (see FIG. 14).

  As shown in FIG. 14, the thread cutting mechanism 300 includes a driven blade 310, a driving blade 320, a transmission member 330, and a moving mechanism 360. The driven blade 310 is plate-shaped, and extends obliquely leftward from the one end 311 toward the other end 312. The one end 311 side is formed narrower than the other end 312 side. The driven blade 310 includes a blade portion 314 at one end 311 and a pin 313 at the other end 312. The pin 313 protrudes downward. The needle plate 9 includes a guide portion 301 on the lower surface. The guide part 301 forms the needle hole 9 </ b> A in a groove shape extending linearly along the driven blade 310. The groove width of the guide portion 301 is substantially the same as the plate width of the driven blade 310. The driven blade 310 engages with the guide portion 301 and is arranged with one end portion 311 facing the needle hole 9A. The U-shaped presser plate 304 in the bottom view is provided along a part of the right end, the left end, and the rear end of the guide portion 301. The presser plate 304 presses the edge of the driven blade 310 from below, and holds the driven blade 310 movably in a straight line within the guide portion 301. The presser plate 304 is fixed to the needle plate 9 with screws 361. The screw 361 abuts on the left end portion 387 of the downstream rotating member 380 and restricts the movement of the driven blade 310 obliquely forward to the left.

  The driven blade 310 moves linearly between the separated position and the approach position by the guidance of the guide unit 301. When the driven blade 310 is positioned at the separated position, the driven blade 310 is positioned at the end of the guide portion 301 on the diagonally left front side. The needle plate 9 includes a pin 302 that protrudes downward and diagonally to the left of the guide portion 301. The tension spring 306 is hooked between the pin 313 of the driven blade 310 and the pin 302 of the needle plate 9. The tension spring 306 biases the driven blade 310 obliquely forward to the left.

  The moving mechanism 360 includes a downstream rotating member 380, an upstream rotating member 340, and a roller member 365. The downstream rotating member 380 includes a first member 381 and a second member 386. The second member 386 has a plate shape that is bent in a substantially L shape when viewed from the bottom, and both ends extend obliquely leftward and forward from the bent portion, respectively. The second member 386 has a shaft hole (not shown) at the bent portion. The shaft hole engages with the support shaft 303. The support shaft 303 is provided on the lower surface of the throat plate 9 and is positioned diagonally to the right of the guide portion 301. The support shaft 303 supports the second member 386 in a horizontally reciprocable manner. The end portion of the second member 386 that extends diagonally to the left is a left end portion 387 of the downstream rotating member 380. The left end portion 387 has a long hole 388 along the direction in which the left end portion 387 extends. The pin 313 of the driven blade 310 engages with the elongated hole 388 of the downstream rotating member 380 and can move within the elongated hole 388. The screw hole 389 is formed at an end portion extending forward of the second member 386.

  The first member 381 has a plate shape that is bent in a substantially L shape when viewed from the bottom, and both end portions extend rearward and rightward from the bent portion, respectively. The first member 381 has a shaft hole (not shown) at the end extending to the rear side. The shaft hole engages with the support shaft 303. The first member 381 has a long hole 382 that penetrates in the up-down direction and extends in the left-right direction at the bent portion. An end portion extending rightward of the first member 381 constitutes a right end portion 383 of the downstream rotating member 380. The right end 383 includes a contact part 384 and a hanging part 385. The contact portion 384 is a portion that protrudes rearward from the right end portion 383. The abutting portion 384 abuts on the action projecting portion 342 of the upstream rotating member 340. The hanging portion 385 projects downward in front of the contact portion 384 and hooks one end of the tension spring 307.

  The first member 381 and the second member 386 have their respective shaft holes engaged with the support shaft 303, and the first member 381 is placed on the lower side of the second member 386. The screw hole 389 of the second member 386 corresponds to the position of the elongated hole 382 of the first member 381. The positions of the first member 381 and the second member 386 can be shifted horizontally by moving the position of the screw hole 389 within the range of the elongated hole 382. The bolt 308 is fastened to the screw hole 389 to fix the first member 381 and the second member 386 together. The downstream rotating member 380 in which the first member 381 and the second member 386 are integrated rotates about the support shaft 303. By adjusting the positional relationship between the first member 381 and the second member 386, the timing at which the roller member 365 of the driving blade 320 acts on the roller protrusion 341 of the upstream rotating member 340 described later is changed. That is, the thread cutting mechanism 300 can shift the timing at which the moving mechanism 360 operates the driven blade 310. Therefore, the thread cutting mechanism 300 can adjust the position where the blade part 324 of the driving blade 320 and the blade part 314 of the driven blade 310 intersect when cutting the upper thread and the lower thread.

  The upstream turning member 340 has a plate shape bent in a substantially L shape when viewed from the bottom, and has a shaft hole (not shown) at the bent portion. The support shaft 309 engages with the shaft hole, and the upstream rotation member 340 rotates about the support shaft 309. The support shaft 309 is provided on the lower surface of the needle plate 9 and is located on the right side of the support shaft 303. The portion on the right end 383 side of the downstream rotating member 380 wraps around the front side from the left side of the support shaft 309, and the contact portion 384 is arranged on the right side of the support shaft 309. The upstream turning member 340 includes a roller protrusion 341 and an action protrusion 342. The roller protrusion 341 protrudes rearward from the shaft hole, which is the radially outer side of the support shaft 309. The roller protrusion 341 can contact the roller member 365 of the drive blade 320. The action protrusion 342 protrudes rightward from the shaft hole. The action protrusion 342 can contact the contact portion 384 of the downstream rotating member 380. The action protrusion 342 includes a pin 343 protruding downward at the base end portion. The tension spring 307 is hooked between the hanging portion 385 provided at the right end portion 383 of the downstream rotating member 380 and the pin 343 of the action protruding portion 342. The tension spring 307 biases the upstream rotating member 340 counterclockwise as viewed from the bottom. When the roller member 365 does not contact the roller protrusion 341, the action protrusion 342 contacts the contact portion 384 of the downstream rotating member 380 by the tension spring 307, and the roller protrusion 341 faces rearward.

  The shape of the driving blade 320 is a plate shape extending in the left-right direction. The drive blade 320 has a shaft hole (not shown) that engages with the support shaft 9B in an intermediate portion. The support shaft 9B supports the drive blade 320 so as to be horizontally reciprocally rotatable. The driving blade 320 includes one end 321 and the other end 322. One end 321 extends to the left of the shaft hole, and the other end 322 extends to the right of the shaft hole. The one end 321 includes a threading portion 323, a blade portion 324, a thread engaging portion 325, a yarn guiding portion 326, and a yarn catching portion 327. The configurations of the threading unit 323, the blade unit 324, the thread engaging unit 325, the thread guiding unit 326, and the thread catching unit 327 are the same as the threading unit 123, the blade unit 124, the thread engaging unit 125, and the thread guide of the first embodiment. Since it is the same as the structure of the part 126 and the thread | yarn capture part 127, description is abbreviate | omitted. The other end 322 includes a pin 319 protruding downward. The pin 319 engages with the through hole 333 of the distal end portion 331 of the transmission member 330. The driving blade 320 is rotatably connected to the transmission member 330. The drive blade 320 has a protrusion 328 that protrudes in front of the shaft hole. The protrusion 328 includes a roller member 365 that protrudes downward.

  The transmission member 330 has the same configuration as the transmission member 230 of the second embodiment. Since the transmission member 330 is the same as the transmission member 230 except that the pin 319 of the drive blade 320 engages with the through hole 333, the description thereof is omitted.

  The operation of the thread cutting mechanism 300 will be described. At the end of sewing, the thread trimming motor 95 drives the output shaft. The thread trimming link mechanism 50 is driven according to the rotation direction and angle of the cam plate 70, and reciprocates the transmission member 330 of the thread trimming mechanism 300 in the front-rear direction. As shown in FIGS. 14 to 17, when the transmission member 330 reciprocates in the front-rear direction, the drive blade 320 reciprocates horizontally around the support shaft 9 </ b> B, and a standby position (see FIG. 14) and a preparation position. (See FIG. 16). When the driving blade 320 is positioned at the standby position, the transmission member 330 is positioned most rearward in the range of movement in the front-rear direction. The thread cutting mechanism 300 arranges the driving blade 320 at the standby position except during thread cutting. When the driving blade 320 is positioned at the preparation position, the transmission member 330 is positioned most forward in the range of movement in the front-rear direction. When the driving blade 320 moves between the standby position and the preparation position, the blade portion 324 moves along an arcuate rotation locus centering on the support shaft 9B. At this time, the blade portion 324 passes through the formation position of the needle hole 9A.

  The tension spring 306 urges the downstream rotating member 380 in the clockwise direction in the bottom view around the support shaft 303. The tension spring 307 hung on the right end 383 of the downstream rotating member 380 biases the pin 343 of the upstream rotating member 340 forward. The action protrusion 342 of the upstream rotation member 340 extends rightward, and the roller protrusion 341 extends rearward. The action protrusion 342 of the upstream rotation member 340 contacts the contact portion 384 of the downstream rotation member 380. When the driving blade 320 is in the standby position, the roller member 365 is positioned to the right of the roller protrusion 341. The roller member 365 is in a state where no driving force is transmitted to the upstream rotating member 340. Due to the biasing force of the tension spring 306, the driven blade 310 is positioned at the end of the guide portion 301 on the diagonally left front side. Therefore, the downstream rotation member 380 does not rotate, and the driven blade 310 is maintained in the separated position.

  When the transmission member 330 moves forward by driving the thread cutting motor 95, the driving blade 320 rotates counterclockwise as viewed from the bottom, and moves from the standby position toward the preparation position. As shown in FIG. 15, when the driving blade 320 moves from the standby position toward the preparation position, the roller member 365 moves to the left and contacts the roller protrusion 341 of the upstream rotation member 340 from the right. The roller member 365 presses the roller protrusion 341 leftward. The upstream rotation member 340 rotates clockwise when viewed from the bottom. The action protrusion 342 moves rearward and moves away from the contact portion 384 of the downstream rotating member 380. The tension spring 307 extends, but the driven blade 310 does not move because it is located at the end of the guide portion 301 on the left diagonal front side. Therefore, the downstream rotation member 380 does not rotate, and the driven blade 310 is maintained in the separated position.

  By the rotation of the driving blade 320, the threading portion 323 passes through the formation position of the needle hole 9A. The threading portion 323 enters the upper thread ring formed by the sewing needle 7 below the needle plate 9. At this time, the side of the upper thread ring that extends from the sewing needle 7 is engaged with the thread engaging portion 325. The thread engaging portion 325 moves rearward with the upper thread being hung, and guides the side of the upper thread ring extending from the sewing needle 7 rearward. When the driving blade 320 is located at the preparation position, the side of the upper thread ring that extends from the sewing needle 7 contacts the thread engaging portion 325 and extends upward through the needle hole 9A. Since the driven blade 310 maintains the position at the separated position, the drive blade 320 and the driven blade 310 form the needle portion 324 and the blade portion 314 form the needle hole 9A in the process in which the drive blade 320 moves from the standby position to the preparation position. Does not overlap in position.

  As the driving blade 320 rotates, the roller member 365 passes through the tip of the roller protrusion 341 while rotating the upstream rotation member 340 counterclockwise as viewed from the bottom. When the roller member 365 moves to the left side of the roller protrusion 341, the upstream rotation member 340 rotates counterclockwise as viewed from the bottom by the biasing force of the tension spring 307. The action protrusion 342 contacts the contact portion 384 of the downstream rotating member 380. The upstream rotation member 340 stops rotating. As shown in FIG. 16, when the driving blade 320 moves to the preparation position, the roller member 365 is positioned to the left of the roller protrusion 341. The driven blade 310 maintains its position at the end of the guide portion 301 on the left diagonal front side. Therefore, the downstream rotation member 380 does not rotate, and the driven blade 310 is maintained in the separated position.

  When the transmission member 330 moves rearward by driving the thread trimmer motor 95, the driving blade 320 rotates clockwise from the bottom and moves from the preparation position toward the standby position. In the process in which the driving blade 320 moves from the preparation position to the standby position, the yarn catcher 327 guides the upper thread ring on the side extending from the cloth and the lower thread to the center of the yarn catcher 327. The side of the upper thread ring that extends from the cloth and the lower thread extend from the thread catcher 327 toward the blade 324 along a recess (not shown) provided on the upper surface of the one end 321.

  As shown in FIG. 17, when the driving blade 320 moves from the preparation position toward the standby position, the roller member 365 moves to the right side and contacts the roller protrusion 341 from the left side. The roller member 365 presses the roller protrusion 341 to the right. The upstream rotation member 340 rotates counterclockwise when viewed from the bottom. The action protrusion 342 moves forward against the biasing force of the tension spring 307 and presses the contact portion 384 of the downstream rotating member 380 forward. The downstream rotation member 380 rotates about the support shaft 303 counterclockwise as viewed from the bottom. The downstream rotating member 380 presses the pin 313 engaged with the elongated hole 388 backward. The pin 313 and the long hole 388 convert the rotation of the downstream rotation member 380 into the linear movement of the driven blade 310. The driven blade 310 moves diagonally right rearward along the guide portion 301 and is positioned at the approach position. While the driven blade 310 is located at the approach position, the blade portion 324 of the drive blade 320 passes the formation position of the needle hole 9A from the rear toward the front. The blade portion 324 intersects the blade portion 314 of the driven blade 310 in the vertical direction when passing the formation position of the needle hole 9A. The position of the driving blade 320 at this time is a cutting position. The blade portion 324 of the driving blade 320 and the blade portion 314 of the driven blade 310 sandwich the side of the upper thread ring that extends toward the cloth and the lower thread, and cut each.

  The transmission member 330 is moved backward by driving the thread cutting motor 95, and the drive blade 320 is moved from the cutting position to the standby position. As the driving blade 320 rotates, the roller member 365 passes through the tip of the roller protrusion 341 while rotating the upstream rotation member 340 counterclockwise as viewed from the bottom. When the roller member 365 moves to the right side of the roller protrusion 341, the roller member 365 is not transmitted to the upstream rotating member 340. The tension spring 306 rotates the downstream rotating member 380 clockwise as viewed from the bottom, and moves the driven blade 310 diagonally to the left of the guide portion 301. As shown in FIG. 14, the driven blade 310 is located at the separated position by the biasing force of the tension spring 306. The driving blade 320 moves to the standby position, and the yarn cutting mechanism 300 ends the yarn cutting.

  The sewing machine 1 can drive the driven blade 310 via the moving mechanism 360 by driving the thread cutting link mechanism 50 and driving the driving blade 320. That is, the sewing machine 1 does not need to provide a drive mechanism for driving the driven blade 310 in addition to the thread cutting link mechanism 50. Therefore, the sewing machine 1 can be assembled with the thread cutting mechanism 300 only by replacing the conventional thread cutting mechanism using a fixed blade instead of the driven blade 310.

  As described above, in the third embodiment, when the driving blade 320 moves from the preparation position to the cutting position, even if the roller member 365 rotates the upstream rotation member 340, the action projecting portion 342 is the downstream rotation member. Do not touch 380. Therefore, the downstream rotation member 380 does not rotate, and the driven blade 310 is maintained at the separated position. Therefore, the thread cutting mechanism 300 can prevent the cutting edge of the driven blade 310 from touching and cutting the upper thread and the lower thread before the driving blade 320 cuts the upper thread and the lower thread at the cutting position.

  Since the driven blade 310 moves linearly, the angle of the blade edge directed toward the drive blade 320 can be kept constant when the upper thread and the lower thread are cut. Therefore, the thread trimming mechanism 300 can perform stable thread trimming.

  The downstream rotating member 380 adjusts the positional relationship between the first member 381 and the second member 386 in accordance with the position of the screw hole 389 in the elongated hole 382, so that the driven blade 310 and the driving blade 320 at the time of thread trimming. Can be adjusted.

  The present invention is not limited to the above embodiments, and various modifications can be made. In the yarn cutting mechanism 100 of the first embodiment, the support shaft 9B supports the driven blade 110 and the driving blade 120 so as to be rotatable coaxially. Not limited to this, the driven blade 110 and the driving blade 120 may be supported so that different support shafts can rotate.

  In the thread trimming mechanism 200 of the second embodiment, the upper surface of the protrusion 254 of the outer circumferential cam 250 forms an inclined surface 255 that is inclined upward from the cam surface 251 side toward the cam surface 253 side. Not limited to this, the inclined surface 255 may not be provided. In this case, the outer peripheral cam 250 may omit the cam surface 252 and provide the protrusions 254 over the entire vertical direction.

  The thread cutting mechanism 200 of the second embodiment adjusts the positional relationship between the cam member 270 and the driving blade 220, and adjusts the timing at which the moving mechanism 260 operates the driven blade 210. Not limited to this, the thread cutting mechanism 200 may adjust the operation timing of the driven blade 210 by, for example, configuring the link member 240 with two members and adjusting the angle at which the link member 240 bends. The positional relationship between the cam member 270 and the drive blade 220 may not be adjustable. In this case, the cam member 270 and the driving blade 220 may be fixed to each other or may be formed integrally.

  The thread cutting mechanism 300 of the third embodiment adjusts the positional relationship between the first member 381 and the second member 386 of the downstream rotating member 380 and adjusts the timing at which the moving mechanism 360 operates the driven blade 310. However, the thread cutting mechanism 300 may adjust the operation timing of the driven blade 310 by adjusting the position of the roller member 365 in the circumferential direction of rotation with respect to the drive blade 320, for example. The positional relationship between the first member 381 and the second member 386 of the downstream rotating member 380 may not be adjustable. In this case, the first member 381 and the second member 386 may be fixed to each other or may be formed integrally.

  In the yarn cutting mechanism 200 of the second embodiment, the driven blade 210 moves linearly between the separated position and the approach position by the guide of the guide unit 201. The movement between the separated position and the approach position of the driven blade 210 is not limited to this, but may be an arc shape instead of a linear shape. In this case, the needle plate 9 may not include the guide portion 201 on the lower surface. The driven blade 210 may not include the pin 213 at the other end portion 212, and the link member 240 may fix the other end portion 212 of the driven blade 210 without having the long hole 243 at the left end portion 241.

  In the thread cutting mechanism 300 of the third embodiment, the driven blade 310 moves linearly between the separated position and the approach position by the guide of the guide unit 301. However, the movement between the separated position and the approach position of the driven blade 310 is not limited to a straight line but may be an arc. In this case, the needle plate 9 may not include the guide portion 301 on the lower surface. The driven blade 310 may not include the pin 313 at the other end 312, and the downstream rotating member 380 may fix the other end 312 of the driven blade 310 without the elongated hole 388 at the left end 387.

  The thread trimming mechanism 200 according to the second embodiment urges the roller member 265 downward together with the link member 240 by the compression spring 245. Not limited to this, the thread trimming mechanism 200 may be provided with a member that urges the roller member 365 downward with respect to the right end portion 242 of the link member 240.

  The thread trimmer mechanism 300 of the third embodiment urges the upstream rotating member 340 counterclockwise as viewed from the bottom by the tension spring 307. For example, the thread trimmer mechanism 300 may be provided with a winding spring that engages with the support shaft 309 and biases the upstream rotating member 340 counterclockwise as viewed from the bottom with respect to the needle plate 9.

  In the thread trimming mechanism 300 according to the third embodiment, the upstream rotating member 340 has a plate shape that is bent in a substantially L shape when viewed from the bottom. However, the upstream rotation member 340 may have a substantially triangular shape as viewed from the bottom as long as the upstream rotation member 340 includes the roller protrusion 341 and the action protrusion 342.

  In the above embodiment, the driven blades 110, 210, and 310 correspond to the “first blade” of the present invention. The blade portions 114, 214, and 314 correspond to the “blade edge” of the first blade of the present invention. The driving blades 120, 220, and 320 correspond to the “second blade” of the present invention. The blade portions 124, 224, and 324 correspond to the “blade edge” of the second blade of the present invention. The thread cutting motor 95 corresponds to the “power source” of the present invention. The rear end portion 152 corresponds to an “end portion” of the groove cam of the present invention. The intermediate portion 153 corresponds to a “bent portion” of the groove cam of the present invention. The support shaft 9B corresponds to the “shaft portion” of the present invention. The tension springs 206 and 306 correspond to the “first biasing member” of the present invention. The right end 242 corresponds to “one end” of the link member of the present invention. The left end 241 corresponds to the “other end” of the link member of the present invention. The compression spring 245 corresponds to the “second biasing member” of the present invention. The long hole 257 corresponds to a “hole” in the present invention. The bolt 229 and the nut 205 correspond to the “fixing member” of the present invention. The support shaft 309 corresponds to the “upstream support shaft” of the present invention. The support shaft 303 corresponds to the “downstream support shaft” of the present invention. The right end 383 corresponds to “one end” of the downstream rotating member of the present invention. The left end portion 387 corresponds to the “other end portion” of the downstream rotating member of the present invention. The long hole 382 corresponds to the “adjustment hole” of the present invention. The screw hole 389 and the bolt 308 correspond to the “assembly member” of the present invention.

1 Sewing machine 7 Sewing needle 9 Needle plate 9A Needle hole 9B Support shaft 95 Thread trimmer motor 100, 200, 300 Thread trimmer mechanism 110, 210, 310 Drive blade 114, 214, 314 Blade portion 120, 220, 320 Drive blade 124, 224 , 324 Blade portion 130, 230, 330 Transmission member 150 Groove cam 152 Rear end portion 153 Intermediate portion 160, 260, 360 Moving mechanism 165, 265, 365 Roll member 201 Guide portion 205 Nut 206 Tension spring 213 Pin 229 Bolt 240 Link member 241 Left end portion 242 Right end portion 243 Long hole 245 Compression spring 250 Peripheral cams 251, 252, 253 Cam surface 254 Projection portion 255 Inclined surface 257 Long hole 301 Guide portions 303, 309 Support shaft 306 Tension spring 308 Bolt 340 Upstream rotating member 341 Roller protrusion 342 Action protrusion 380 Downstream rotating member 3 81 First member 382 Long hole 383 Right end 386 Second member 387 Left end 389 Screw hole

Claims (11)

A first blade provided on the lower side of a needle plate having a needle hole through which a sewing needle passes;
A standby position where the cutting edge is provided at the lower side of the needle plate and arranged at a position away from the needle hole, and a cutting position where the cutting edge intersects the cutting edge of the first blade at the formation position of the needle hole A second blade movable between a preparation position for disposing a cutting edge at a position away from the needle hole on the side opposite to the standby position with respect to the cutting position;
A transmission member that transmits a driving force of a power source to the second blade, and moves the second blade between the standby position and the preparation position;
With
The second blade moves from the standby position to the preparation position via the transmission member by driving the power source, and then moves from the preparation position to the cutting position.
When the second blade moves from the preparation position to the cutting position, a thread cutting mechanism that captures the upper thread and the lower thread and cuts in cooperation with the first blade;
The first blade is movable between an approach position where a blade tip is disposed at a formation position of the needle hole and a separation position spaced from the needle hole with respect to the approach position;
A moving mechanism that operates with the driving force of the power source together with the transmission member and moves the first blade between the approach position and the separation position;
When the power source is not driven, the first blade is located at the separated position, and the second blade is located at the standby position,
When the power source is driven, when the second blade is moved from the preparation position to the cutting position by the transmission member, the moving mechanism moves the first blade from the separated position to the approach position. Characteristic thread trimming mechanism. When the power source is driven, the transmission member reciprocates in a predetermined direction parallel to the horizontal direction to reciprocate the second blade between the standby position and the preparation position,
The moving mechanism is
A groove cam provided integrally with the transmission member, having a bent portion bent in a direction crossing the predetermined direction, and extending in a groove shape along the predetermined direction;
A roller member provided on the first blade and fitted into the groove cam;
Including
When the second blade is positioned at the standby position or the preparation position by the movement of the transmission member, the roller member is positioned at the end of the groove cam and the first blade is disposed at the separation position;
2. The yarn according to claim 1, wherein when the second blade is positioned at the cutting position, the roller member is positioned at a bent portion of the groove cam and the first blade is disposed at the approach position. Cutting mechanism. The first blade and the second blade are flat.
Provided on the needle plate, the first blade and the second blade are coaxially arranged in an axial direction, and each has a shaft portion that rotatably supports,
When the transmission member reciprocates in the predetermined direction, the rotation trajectory of the blade edge of the second blade rotated about the shaft portion by the transmission member is the rotation trajectory of the first blade rotated by the movement mechanism. Including the position that overlaps the rotation trajectory of the cutting edge,
The blade edge of the second blade intersects the blade edge of the first blade when the first blade is located at the approach position and the second blade is located at the cutting position. The thread trimming mechanism described. A shaft portion provided on the needle plate and rotatably supporting the second blade;
A first biasing member that biases the first blade from the approach position toward the separation position;
With
The moving mechanism is
A cam surface that is pivotable with the second blade about the shaft portion, extends radially outward of the shaft portion in a circumferential direction, and extends radially outward to a portion of the cam surface in the circumferential direction. An outer peripheral cam having a protruding portion that protrudes;
A roller member capable of rolling along the cam surface of the outer peripheral cam;
A shaft member provided on the needle plate is rotatably supported, the roller member is provided at one end, and the link member is connected to the first blade at the other end,
Including
The first urging member presses the roller member against the cam surface via the link member,
When the power source is driven, the transmission member reciprocates in a predetermined direction parallel to the horizontal direction to reciprocate the second blade between the standby position and the preparation position,
When the second blade is positioned at the standby position or the preparation position due to the movement of the transmission member, the roller member abuts against a portion of the cam surface other than the protrusion to place the first blade at the separation position. Placed in
2. The roller member according to claim 1, wherein when the second blade is located at the cutting position, the roller member abuts against the protrusion of the cam surface and the first blade is disposed at the approach position. Thread trimming mechanism. The moving mechanism includes a second urging member that urges the roller member to one side in the axial direction of the shaft portion,
The protrusion protrudes on one side in the axial direction of the cam surface, and a surface facing the other axial direction is one side in the axial direction from one end side to the other end side in the circumferential direction of the shaft portion. Forming an inclined surface inclined from one side to the other,
When the second blade moves from the standby position to the preparation position, the roller member moves in the axial direction of the protrusion along the inclined surface from one end side to the other end side in the circumferential direction of the shaft portion. Moving the other side, placing the first blade in the spaced position by the biasing of the first biasing member,
When the second blade moves from the preparation position to the cutting position, the roller member moves along the protrusion from the other end side in the circumferential direction of the shaft portion toward the one end side, and the link member The thread cutting mechanism according to claim 4, wherein the first blade is moved from the separated position to the approach position via a thread. The needle plate includes a guide portion that guides the movement of the first blade in a straight line,
The link member has, at the other end, an elongated hole that engages with a pin provided on the first blade,
The pin moves in the range of the elongated hole by the rotation of the link member, and the first blade is converted into power that moves linearly between the separation position and the approach position. The thread trimming mechanism according to claim 4 or 5. The outer circumferential cam has a hole extending in the circumferential direction of the shaft portion,
The second blade has a fixing member that integrally fixes the second blade and the outer peripheral cam,
The thread cutting mechanism according to any one of claims 4 to 6, wherein the outer circumferential cam can be fixed by the fixing member by changing a fixing position with respect to the second blade within the range of the hole. . A first biasing member that biases the first blade from the approach position toward the separation position;
Provided on the needle plate, comprising a shaft portion that rotatably supports the second blade,
The moving mechanism is
A roller member provided on the second blade and projecting outward in the radial direction of the shaft, and operating together with the transmission member;
An upstream rotating member that is rotatable about an upstream support shaft provided on the needle plate;
A downstream rotating member that is rotatable about a downstream support shaft provided on the needle plate;
Including
The upstream rotating member protrudes outward in the radial direction of the upstream support shaft, a roller protrusion that can contact the roller member, and an action protrusion that protrudes radially outward in a direction different from the roller protrusion. And
One end of the downstream rotating member can be brought into contact with the action protrusion, and the other end is connected to the first blade,
When the second blade moves from the standby position to the preparation position, the action protrusion presses the roller protrusion in a direction away from the one end of the downstream rotating member, and the first blade Arranged in the separated position by the biasing of one biasing member,
When the second blade moves from the preparation position to the cutting position, the working protrusion presses the roller protrusion in a direction to contact the one end of the downstream rotating member, and the first blade 2. The thread trimming mechanism according to claim 1, wherein the thread trimming mechanism moves from the separated position to the approach position via an action protrusion and the downstream rotating member. The needle plate includes a guide portion that guides the movement of the first blade in a straight line,
The yarn cutting mechanism according to claim 8, wherein the moving mechanism moves the first blade linearly between the separated position and the approach position. The downstream rotating member is
A first member that is pivotable about the downstream support shaft and extends between the one end and the downstream support shaft;
A second member that is pivotable about the downstream support shaft and extends between the other end and the downstream support shaft;
With
The first member has an adjustment hole that is a long hole between the one end and the downstream support shaft;
The second member has an assembly member that engages with the adjustment hole and is assembled to the first member;
10. The downstream rotating member can be assembled with the first member and the second member by changing the assembly position of the assembly member within the range of the adjustment hole. The thread trimming mechanism described. A first blade provided on the lower side of a needle plate having a needle hole through which a sewing needle passes;
A standby position where the cutting edge is provided at the lower side of the needle plate and arranged at a position away from the needle hole, and a cutting position where the cutting edge intersects the cutting edge of the first blade at the formation position of the needle hole A second blade movable between a preparation position for disposing a cutting edge at a position away from the needle hole on the side opposite to the standby position with respect to the cutting position;
A transmission member that transmits a driving force of a power source to the second blade, and moves the second blade between the standby position and the preparation position;
With
The second blade moves from the standby position to the preparation position via the transmission member by driving the power source, and then moves from the preparation position to the cutting position.
When the second blade moves from the preparation position to the cutting position, the sewing machine includes a thread cutting mechanism that captures an upper thread and a lower thread and cuts the upper blade and the first blade in cooperation with each other.
The first blade is movable between an approach position where a blade tip is disposed at a formation position of the needle hole and a separation position spaced from the needle hole with respect to the approach position;
The yarn cutting mechanism includes a moving mechanism that operates with the driving force of the power source together with the transmission member and moves the first blade between the approach position and the separation position,
When the power source is not driven, the first blade is located at the separated position, and the second blade is located at the standby position,
When the power source is driven, when the second blade is moved from the preparation position to the cutting position by the transmission member, the moving mechanism moves the first blade from the separated position to the approach position. Characteristic sewing machine.

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