JP2017099657A - sewing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sewing machine capable of making cut ends of a needle thread and a bobbin thread short remaining on a sewing object after cutting.SOLUTION: At the start of sewing, a thread grip member 160 arranges a thread hole 165 below a needle hole 90 and passes a needle thread. The thread grip member 160 rotates counter-clockwise in a bottom view, and holds the needle thread between itself and a thread pressing member 180. The thread grip member 160 moves to a release position and loosens the holding of the needle thread. A sewing machine sews the needle thread in seams and continues sewing. One end part 161 of the thread grip member 160 is connected integrally to a protection member 175 via an arm part 170. At the release position, the protection member 175 is located at a protection position below a blade part 114 of a stationary blade 110. On a cross section including a center position of the needle hole 90, the protection member 175 crosses a virtual straight line connecting an edge part of the needle hole 90 and the blade part 114, it is prevented that the needle thread and the bobbin thread coming into contact with the blade part 114. Therefore, the stationary blade 110 can arrange the blade part 114 closer to the needle hole 90 than a conventional one.SELECTED DRAWING: Figure 11

Description

  The present invention relates to a sewing machine provided with a thread cutting mechanism 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. When the fixed blade is fixed to the needle plate in a state where the blade edge is closer to the needle hole than the thread cutting mechanism, the lower thread may touch the fixed blade at the time of sewing and may break the thread. Therefore, it has been difficult to shorten the upper thread and lower thread ends of the cloth.

  An object of the present invention is to provide a sewing machine that can shorten the upper thread and the lower thread that are left on a sewing object after cutting.

  According to the first aspect of the present invention, the fixed blade is provided on the lower side of the needle plate having the needle hole through which the sewing needle passes, and the blade tip is disposed toward the needle hole, and the lower side of the needle plate is rotated horizontally. A movable blade capable of reciprocally moving along a path where the blade edge intersects the blade edge of the fixed blade, and a power source that applies a driving force to the movable blade and reciprocates the movable blade. A sewing machine that captures an upper thread and a lower thread with the movable blade when the movable blade is driven by a source, and cuts the upper thread and the lower thread by crossing the blade edge of the movable blade and the blade edge of the fixed blade; A protective member positioned at a protective position below the fixed blade when the movable blade is not driven and positioned at a retracted position away from the needle hole with respect to the blade edge of the fixed blade when the movable blade is driven, When the protective member is located at the protective position, the fixed blade, the protective member, and the needle hole The end of the protective member on the side of the needle hole is in contact with an imaginary straight line connecting the edge of the needle hole on the side where the protective member is located and the cutting edge of the fixed blade. A sewing machine characterized by crossing is provided.

  The protection member arranges the blade edge of the fixed blade between the protection member and the needle plate when the movable blade is not driven, and prevents the blade edge of the fixed blade from being positioned on the path of the upper thread and the lower thread. That is, the protective member prevents the upper thread and the lower thread from touching the cutting edge of the fixed blade during sewing, and can reduce the possibility of thread breakage. Since the protective member prevents thread breakage of the upper thread and the lower thread by the blade edge of the fixed blade, the fixed blade can be disposed with the blade edge closer to the needle hole than in the past. Therefore, the sewing machine can shorten the upper end of the upper thread and the lower thread remaining on the sewing target after cutting, as compared with the case where the upper thread and the lower thread are cut away from the needle hole.

  In the first aspect, the cutting edge of the fixed blade extends in an extending direction perpendicular to the center line of the needle hole, and the protective member has an end portion on the needle hole side extending along the extending direction, You may have a length more than a diameter.

  When sewing, the upper thread and lower thread pass through the needle hole and extend below the needle plate. The extending length of the protective member is not less than the diameter of the needle hole. Even if the upper thread and the lower thread move within the range of the needle hole, the protective member can reliably prevent the upper thread and the lower thread from touching the cutting edge of the fixed blade.

  The first aspect is provided at the lower end of the needle plate so as to be horizontally rotatable, and has a thread hole through which the upper thread passes at the first end, and the thread hole is positioned below the needle hole at the start of sewing. A thread gripping member that moves between a preparation position to perform and a separation position in which the thread hole is located away from the needle hole with respect to the preparation position, and can be horizontally rotated under the needle plate A second end portion that can be held by holding the upper thread between the first end portion of the thread gripping member and is driven by the thread gripping member, and the second end portion is the thread hole. And a thread holding member that sandwiches the upper thread by moving to a position that overlaps with the upper and lower direction, and the thread gripping member and the protection member move the thread gripping member from the preparation position toward the separated position. The thread gripping member is provided integrally with an arm portion extending from the first end portion in a direction opposite to the direction. When the yarn hole moves to a position overlapping the second end portion in the vertical direction and moves to a release position between the capture position and the separation position, The hole may move to a position away from the second end to loosen the upper thread, and the protection member may be positioned at the protection position when the thread gripping member is moved to the release position. .

  The thread gripping member and the thread presser member can sandwich and hold the end of the upper thread at the start of sewing. The protective member is provided integrally with the thread gripping member. The protection member is positioned at the protection position when the thread gripping member and the thread pressing member are loosened after holding the end portion of the upper thread. Therefore, since the sewing machine can hold the upper thread and move the protection member only by driving the thread gripping member, it is not necessary to provide a separate movement mechanism for the protection member.

  In the first aspect, the thread gripping member is positioned below the fixed blade, the arm portion is bent in the vertical direction, and the first bent portion is disposed above the first end portion. You may have.

  Since the arm portion is bent in the vertical direction by the first bent portion, the protective member can be arranged in a state closer to the cutting edge of the fixed blade at the protective position. Therefore, the protective member shortens the distance between the fixed blade and the blade, and more reliably prevents the upper thread and lower thread from touching the fixed blade during sewing, further reducing the possibility of thread breakage. it can.

  In the first aspect, when the thread gripping member is located at the capture position, the protective member and the first end part, and the arm part and the rotation center of the thread gripping member are located at the position where the needle hole is formed. The arm portion may have a second bent portion that is bent in the horizontal direction on the opposite side to the rotation center of the thread gripping member.

  When the thread gripping member is located at the capture position, the arm portion does not overlap with the needle hole formation position in the vertical direction. Therefore, the arm portion hardly interferes with the upper thread and the lower thread that pass through the needle hole. Since the arm does not apply a load to the upper thread and the lower thread, the sewing machine can be sewn smoothly.

  In the first aspect, the power source may apply a driving force to the thread gripping member and move the thread gripping member between the preparation position and the separation position.

  A power source that applies a driving force to the movable blade also applies a driving force to the thread gripping member. Therefore, the sewing machine does not require a separate power source for driving the thread gripping member.

  In the first aspect, the thread gripping member includes a projecting portion that protrudes in a vertical direction between a rotation center of the thread gripping member and the first end portion, and the thread presser member includes the thread presser member. A contact portion that is a side surface against which the protrusion comes into contact when the thread gripping member moves from the preparation position to the release position. When the thread gripping member moves from the preparation position to the release position, the thread gripping member is brought into contact with the contact portion to rotate the thread presser member in the same direction as the thread gripping member. A first abutting portion with which the projecting portion abuts when the gripping member is positioned between the preparation position and the release position; and the projection when the thread gripping member is positioned on the side of the separation position with respect to the release position. The first part is in contact with the first contact part and is recessed on the opposite side of the projecting part. A contact portion may include a.

  Since the protection member is moved away from the path of the movable blade when the movable blade is driven, the range in which the thread gripping member rotates is larger than the configuration without the conventional protection member. The thread presser member rotates following the thread gripping member. Since the thread presser member includes the second contact part that is recessed to the opposite side of the projecting part from the first contact part, the amount of rotation of the thread presser member when the thread gripping member is located on the separated position side from the release position. Can be suppressed. Therefore, the sewing machine does not need to ensure a large area for the thread presser member to rotate below the needle plate.

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. FIG. 5 is a bottom view of the thread gripping mechanism 150 when the thread gripping member 160 is in a separated position. 5 is a bottom view of the thread gripping member 160. FIG. FIG. 6 is a side view of the thread gripping member 160 viewed in the direction of arrow A in FIG. 5. 6 is a bottom view of the thread presser member 180. FIG. 3 is a perspective view of a needle plate 9 and a drive mechanism 15. FIG. FIG. 6 is a bottom view of the thread gripping mechanism 150 when the thread gripping member 160 is in a preparation position. FIG. 5 is a bottom view of the thread gripping mechanism 150 when the thread gripping member 160 is in a capture position. It is a bottom view of the thread gripping mechanism 150 when the thread gripping member 160 is in the release position. 12 is a cross-sectional view of the needle plate 9, the fixed blade 110, and the protection member 175 including the center position C of the needle hole 90 viewed from the side in the arrow direction along the line BB in FIG. It is sectional drawing of the needle plate 9, the fixed blade 110, and the protection member 275 of the modification which the edge part of the protection member 275 touches the virtual straight line V1. It is a bottom view showing a modification of the protection member 375.

  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 90 (see FIG. 8) 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 21 on the upper portion of the back wall. The arm portion 4 extends forward substantially parallel to the bed portion 2 from the upper end of the pedestal portion 3 and includes a main shaft that is driven by a sewing machine motor 21 therein. 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 150 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 150 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 the thread cutting motor 25 to the back side of the bed portion 2 via a bracket 80. The thread trimming motor 25 is a pulse motor and is a drive source for the thread trimming mechanism 100 and the thread gripping mechanism 150.

  In the following description, the direction of each member constituting the thread trimming mechanism 100 will be described in the direction at the position where the movable blade 120 stands by when not driven (see FIG. 4). As shown in FIG. 4, the thread cutting mechanism 100 includes a fixed blade 110 and a movable blade 120. The fixed blade 110 is a plate material that is substantially L-shaped when viewed from the bottom. One end 111 of the fixed blade 110 is an end of a portion extending rightward and rearward from the bent portion, and the other end 112 is an end of a portion extending leftward and rearward from the bent portion. The other end 112 of the fixed blade 110 is fixed to the lower surface of the needle plate 9 with two screws 113. One end 111 of the fixed blade 110 is located on the left front side of the needle hole 90. The one end portion 111 includes a blade portion 114. The blade portion 114 extends in the extending direction, which is the horizontal direction and the direction perpendicular to the center line of the needle hole 90, and is bent downward at one end of the fixed blade 110.

  The shape of the movable blade 120 is a plate shape extending in the left-right direction. The movable blade 120 has a shaft hole (not shown) that engages with the support shaft 91 at an intermediate portion. The support shaft 91 supports the movable blade 120 so as to be able to reciprocate horizontally. The movable blade 120 is disposed below the fixed blade 110. The movable blade 120 includes one end 121 and the other end 122. One end 121 is an end of a portion extending to the left of the shaft hole, and the other end 122 is an end of a portion extending 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 movable blade 120 in the vertical direction. When the movable blade 120 rotates, the blade portion 124 moves along an arcuate locus centering on the support shaft 91 and passes through the formation position of the needle hole 90. 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 one end 53A of the third link 53. During the operation of the thread cutting mechanism 100, the third link 53 reciprocates in the front-rear direction, and the movable blade 120 reciprocates.

  In the following description, the direction of each member constituting the thread gripping mechanism 150 will be described in the direction when the thread gripping member 160 is located at the separation position (see FIG. 4). The output shaft of the thread trimming motor 25 has the thread gripping member 160 disposed at a separated position and the blade portion 124 of the movable blade 120 disposed at the front side of the needle hole 90 in a state before starting sewing. As shown in FIGS. 4 to 7, the thread gripping mechanism 150 includes a thread gripping member 160 and a thread presser member 180. The shape of the thread gripping member 160 is a substantially L-shaped plate that bends at a substantially right angle at the central portion 163. The central part 163 has a hole 164. The support shaft 92 is fixed to the lower surface of the needle plate 9 and engages with the hole 164 to support the thread gripping member 160 in a rotatable manner. A portion extending forward from the central portion 163 is bent leftward and forward at one end portion 161. The one end 161 includes a thread hole 165 and a pin 166. The thread hole 165 penetrates the thread gripping member 160 in the vertical direction. The thread hole 165 allows the upper thread to pass when gripping the thread. The pin 166 has a cylindrical shape. The pin 166 is provided on the rear side of the thread hole 165 and protrudes upward. The pin 166 contacts the contact portion 190 of the thread presser member 180.

  The protection member 175 is provided integrally with the thread gripping member 160 via the arm portion 170. The protection member 175 prevents the upper thread and the lower thread from touching the blade portion 114 of the fixed blade 110 during sewing. The arm portion 170 extends rightward from the right corner portion of the front end of the one end portion 161 and is connected to the protection member 175. The arm part 170 has a first bent part 171 and a second bent part 172. The first bent portion 171 is bent stepwise with the arm portion 170 facing upward, and the protective member 175 is disposed above the one end portion 161. The second bent portion 172 bends rightward and rearward on the right side of the first bent portion 171. The protection member 175 has a protection surface 176 that extends linearly from the left rear to the right front. The protective surface 176 includes a surface facing the right rear side and a surface facing the rear right side and the lower side. The length L that the protective surface 176 extends is equal to or larger than the diameter D of the needle hole 90 and is shorter than the blade span length of the blade portion 114 of the fixed blade 110. The diameter D of the needle hole 90 is the inner diameter of the portion that penetrates the needle plate 9 vertically. When the thread gripping member 160 is located at the release position (see FIG. 11), the direction in which the protection surface 176 extends is along the extending direction of the blade portion 114 of the fixed blade 110.

  The other end portion 162 of the thread gripping member 160 is an end portion of a portion extending leftward from the central portion 163. The other end 162 has a hole 167. The hole portion 167 engages with the pin 93 of the one end portion 63 </ b> A of the third link 63 and connects the other end portion 162 to the third link 63. The third link 63 extends forward from the thread clamp link mechanism 60 (see FIG. 8). When the third link 63 moves in the front-rear direction, the thread gripping member 160 reciprocates horizontally around the support shaft 92.

  The shape of the thread presser member 180 is a substantially L-shaped plate shape in which the central portion 183 is bent at a substantially right angle. One end 181 of the thread presser member 180 is an end of a portion extending forward from the central portion 183, and the other end 182 is an end of a portion extending rightward from the central portion 183. The central part 183 has a hole 184. The support shaft 94 is fixed to the lower surface of the needle plate 9 and engages with the hole 184 to support the thread presser member 180 in a rotatable manner. The one end 181 extends to the right and bends downward in a stepped manner to form a grip 186. The thread presser member 180 is disposed above the thread gripping member 160. At least a part of the one end 181 of the thread presser member 180 and the one end 161 of the thread gripping member 160 are arranged in the vertical direction. The grip part 186 is closer to the one end part 161 of the thread gripping member 160 than the one end part 181 in the vertical direction.

  The other end 182 has a hole 185. One end of the tension spring 45 engages with the hole 185. The other end of the tension spring 45 is hooked on a hanging portion 95 provided on the right rear side of the support shaft 92. The other end portion 182 of the thread presser member 180 is located in front of the hanging portion 95. The tension spring 45 urges the other end 182 rearward, and rotates the thread presser member 180 about the support shaft 94 in the clockwise direction when viewed from the bottom.

  The thread presser member 180 has a contact portion 190. The contact portion 190 is a side portion of a portion extending between the central portion 183 and the one end portion 181. The contact part 190 includes a first contact part 191 and a second contact part 192. The first contact portion 191 is a portion on the one end portion 181 side. When the thread gripping member 160 is located at the preparation position (see FIG. 9), the capture position (see FIG. 10), or the release position (see FIG. 11), the pin 166 contacts the first contact portion 191 from the right side.

  The second contact part 192 is a part closer to the center part 183 than the first contact part 191. The second contact portion 192 is recessed to the left side of the first contact portion 191. When the thread gripping member 160 is positioned at the separated position (see FIG. 4), the pin 166 contacts the second contact portion 192 from the right side. When the pin 166 contacts the second contact portion 192, the thread presser member 180 rotates counterclockwise as viewed from the bottom as compared with the case where the first contact portion 191 contacts the position extended to the center portion 183 side. The moving size can be suppressed.

  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 150. As shown in FIG. 8, the drive mechanism 15 includes a thread trimming motor 25, a cam plate 70, a thread trimming link mechanism 50, and a thread gripping link mechanism 60. The thread trimming motor 25 is fixed to the lower back portion (see FIG. 1) of the bed portion 2 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 cutting motor 25 is fixed to the upper surface of the bracket 80, and an output shaft (not shown) is disposed in the bracket 80. The cam plate 70 is disposed in the bracket 80 and fixed to the output shaft of the thread cutting motor 25. 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 cam plate 70 is formed so that the angular range in which the groove cam drives the thread trimming link mechanism 50 and the angular range in which the outer peripheral cam drives the thread gripping link mechanism 60 differ at the rotation angle of the output shaft of the thread trimming motor 25. To do.

  The thread trimming link mechanism 50 includes a first link 51, a second link 52, and a third link 53 in order from the thread trimming motor 25 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 portion 52 </ b> A of the second link 52 is fixed to the other end portion 53 </ b> B of the third link 53 with two screws 57. The third link 53 extends forward substantially linearly from the other end 53B toward the thread trimming mechanism 100. One end 53 </ b> A of the third link 53 is rotatably connected to the movable blade 120 via a pin 119. When the thread trimming motor 25 is driven, the thread trimming link mechanism 50 drives the movable blade 120 of the thread trimming mechanism 100 according to the rotation direction and angle of the cam plate 70 to cut the upper thread and the lower thread.

  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 25 side toward the thread gripping mechanism 150 side. The first link of the thread grasping link mechanism 60 is formed in a substantially straight line shape in plan view. The bracket 80 supports the first link so as to be 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 150. One end 63A of the third link 63 is rotatably connected to the thread gripping member 160 via a pin 93 (see FIG. 4).

  The operation of the thread trimming mechanism 100 and the thread gripping mechanism 150 will be described. At the start of sewing, the thread trimming motor 25 drives the output shaft to reciprocate the cam plate 70 in a predetermined direction. The thread gripping link mechanism 60 rotates the thread gripping member 160 of the thread gripping mechanism 150 according to the rotation direction and angle of the cam plate 70. As shown in FIG. 9, when the third link 63 moves forward, the thread gripping member 160 rotates clockwise as viewed from the bottom and moves to the preparation position (see FIG. 9). In the preparation position, the thread hole 165 of the one end portion 161 is located below the needle hole 90. The pin 166 moves to the right and moves away from the contact portion 190 of the thread presser member 180. The thread presser member 180 is rotated clockwise as viewed from the bottom by the biasing force of the tension spring 45. The thread presser member 180 stops rotating at a position where the other end 182 contacts the support shaft 92.

  The upper thread of the first stitch at the start of sewing passes through the cloth and extends downward from the needle hole 90 of the needle plate 9 through the thread hole 165 of the thread gripping member 160. After the first sewing needle 7 is separated from the thread hole 165, the thread cutting motor 25 rotates the cam plate 70, and the third link 63 moves rearward according to the rotation direction and angle of the cam plate 70. As shown in FIG. 10, when the third link 63 moves rearward, the thread gripping member 160 rotates counterclockwise when viewed from the bottom and moves to the capture position (see FIG. 10). The upper thread passing through the thread hole 165 moves to the left together with the one end portion 161 of the thread gripping member 160. In the capture position, the thread hole 165 is located below the bent portion of the one end 181. The gripping portion 186 of the thread presser member 180 is located to the right of the thread hole 165 and is close to the one end 161 in the vertical direction. The one end portion 161 and the gripping portion 186 sandwich the upper thread extending between the thread hole 165 and the needle hole 90 in the gap, and bend and hold the upper thread. The thread gripping mechanism 150 holds the upper thread at the start of sewing, thereby preventing the end of the upper thread from being caught in the seam.

  In the capture position, the protection member 175 moves to a position having the formation position of the needle hole 90 between the end portion 161 and the protection member 175. The arm portion 170 has a shape in which the second bent portion 172 bends to the right rear. Therefore, the arm portion 170 extends from the one end portion 161 through the front side of the formation position of the needle hole 90, is bent at the second bent portion 172, and is connected to the protection member 175 located on the right side of the needle hole 90. Therefore, when the thread gripping member 160 is located at the capture position, the arm portion 170 does not overlap the formation position of the needle hole 90 in the vertical direction. Therefore, the arm portion 170 does not interfere with the upper thread and the lower thread that pass through the needle hole 90.

  After the sewing has progressed and the needle drop has occurred a predetermined number of times (for example, 2 to 3 times), the thread trimming motor 25 rotates the cam plate 70, and the third link 63 is further rearward depending on the rotation direction and angle of the cam plate 70. Move to. As shown in FIG. 11, when the third link 63 moves further rearward, the thread gripping member 160 rotates counterclockwise as viewed from the bottom and moves to the release position (see FIG. 11). The pin 166 presses the first contact portion 191 to the left, and rotates the thread presser member 180 counterclockwise as viewed from the bottom against the urging force of the tension spring 45. In the release position, the thread hole 165 is positioned so as to be shifted from the one end 181 of the thread presser member 180 by about half the size of the thread hole 165 in the front-rear direction. Since the overlapping position of the one end portion 161 and the gripping portion 186 is displaced from the direction connecting the thread hole 165 and the needle hole 90, the upper thread is easily pulled out from the gap between the one end portion 161 and the gripping portion 186. As the sewing progresses, the cloth moves and pulls the upper thread, so that the end of the upper thread comes out of the gap between the one end 161 and the gripping part 186 and also comes out of the thread hole 165. The thread trimming motor 25 maintains the state where the thread gripping member 160 is located at the release position. The sewing machine 1 continues sewing by winding the upper thread that has come out of the thread hole 165 into the seam.

  In the release position, the protection member 175 moves to a protection position below the blade portion 114 of the fixed blade 110. In the protective position, the protective surface 176 extends along the extending direction of the blade 114. The protection member 175 covers the blade portion 114 from below, and the blade portion 114 is disposed between the protection member 175 and the needle plate 9. As shown in FIG. 12, when the protection member 175 is located at the protection position, the end of the protection member 175 on the needle hole 90 side is located closer to the needle hole 90 than the blade portion 114. Specifically, the virtual straight line V <b> 1 is a straight line connecting the edge E on the side where the protection member 175 of the needle hole 90 is located and the blade 114 of the fixed blade 110. The end of the protection member 175 on the side of the needle hole 90 intersects the virtual straight line V1. In other words, the blade portion 114 is not exposed to the needle hole 90 side with respect to the virtual straight line V2 passing through the protection surface 176 of the protection member 175 and the edge E of the needle hole 90.

  At the time of sewing, an upper thread and a lower thread represented by a thread T in FIG. 12 pass through the needle hole 90 and extend below the needle plate 9. The thread T moves to the front, back, left and right below the needle plate 9 according to the sewing state. The protection member 175 prevents the blade portion 114 from being exposed on the path of the thread T. Therefore, when the thread T moves to the fixed blade 110 side, it contacts the edge E of the needle hole 90 and the protection surface 176 of the protection member 175, but does not contact the blade 114. The protection member 175 prevents the thread T from being broken by contact with the blade portion 114.

  At the time of the final stitch before the end of sewing, the thread trimming motor 25 rotates the cam plate 70, and the third link 63 moves further rearward according to the rotation direction and angle of the cam plate 70. As shown in FIG. 4, the thread gripping member 160 rotates counterclockwise when viewed from the bottom, and moves to the separated position. The pin 166 moves to the second contact portion 192 and presses the second contact portion 192 leftward. The thread presser member 180 further rotates counterclockwise as viewed from the bottom against the urging force of the tension spring 45. Since the second contact portion 192 is recessed to the left of the first contact portion 191, further rotation of the thread presser member 180 is suppressed, and the load applied to the tension spring 45 is reduced. In the separated position, the protection member 175 is located at a retracted position away from the needle hole 90 with respect to the blade portion 114 of the fixed blade 110. The retracted position is a position where the protective member 175 does not contact the movable blade 120 even when the movable blade 120 rotates.

  The thread cutting motor 25 drives the output shaft, reciprocates the cam plate 70, and performs a thread cutting operation. During the thread trimming operation, the thread gripping member 160 maintains the state of being located at the separated position.

  The thread trimming link mechanism 50 is driven according to the rotation direction and angle of the cam plate 70, and reciprocates the third link 53 of the thread trimming mechanism 100 in the front-rear direction. When the third link 53 reciprocates in the front-rear direction, the movable blade 120 rotates horizontally around the support shaft 91 via the pin 119, and the one end 121 is moved to the position on the front side and the rear side of the needle hole 90. Reciprocates between positions. The thread trimming mechanism 100 arranges the one end 121 of the movable blade 120 at a position in front of the needle hole 90 except during thread trimming.

  When the third link 53 moves forward by driving the thread cutting motor 25, the movable blade 120 rotates counterclockwise as viewed from the bottom, and the one end 121 moves from the front position of the needle hole 90 to the rear position. To do. Since the protection member 175 is located at the retracted position, the movable blade 120 does not contact the protection member 175. When the one end portion 121 moves to the rear side of the needle hole 90, the stringing portion 123 of the movable blade 120 passes through the formation position of the needle hole 90. 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 movable blade 120 is positioned on the rear side of the needle hole 90, the side of the upper thread ring that extends from the sewing needle 7 comes into contact with the thread engaging portion 125 and extends upward through the needle hole 90.

  When the thread cutting motor 25 is driven in the reverse direction and the third link 53 moves backward, the movable blade 120 rotates clockwise as viewed from the bottom, and moves from the rear position of the needle hole 90 to the front position. . In the process of moving the movable blade 120, the yarn catching portion 127 guides the side of the upper thread ring extending from the cloth and the lower thread 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. The blade portion 124 of the movable blade 120 passes through the formation position of the needle hole 90 from the rear to the front. The blade portion 124 of the movable blade 120 intersects the blade portion 114 of the fixed blade 110 in the vertical direction when passing through the formation position of the needle hole 90. The blade portion 124 of the movable blade 120 and the blade portion 114 of the fixed blade 110 sandwich the side of the upper thread ring that extends toward the cloth and the lower thread, and cut each.

  The third link 53 moves rearward by driving the thread cutting motor 25, and the movable blade 120 moves to the front position of the needle hole 90 (see FIG. 4). The yarn cutting mechanism 100 ends the yarn cutting operation. When the output shaft returns to the state before the start of sewing, the thread trimming motor 25 stops driving and enters a non-driving state.

  Since the sewing machine 1 is provided with the protective member 175 integrally with the thread gripping member 160, the thread gripping operation is performed only by driving the thread gripping mechanism 150, and the protective member 175 is moved between the protective position and the retracted position. it can. That is, the sewing machine 1 does not need to provide a drive mechanism for moving the protection member 175 between the protection position and the retracted position in addition to the thread grip link mechanism 60. Therefore, the sewing machine 1 can be assembled with the thread gripping mechanism 150 only by replacing the thread gripping member 160 and the thread presser member 180 with a thread gripping mechanism having a conventional configuration.

  As described above, the protective member 175 has the blade portion 114 of the fixed blade 110 disposed between the protective member 175 and the needle plate 9 when the movable blade 120 is not driven, and the blade portion 114 of the fixed blade 110 is the upper thread. And prevent it from being positioned on the lower thread path. That is, the protection member 175 prevents the upper thread and the lower thread from touching the blade portion 114 of the fixed blade 110 during sewing, and can reduce the possibility of thread breakage. Since the protective member 175 prevents the upper thread and the lower thread from being broken by the blade portion 114 of the fixed blade 110, the fixed blade 110 can be disposed with the blade portion 114 closer to the needle hole 90 than in the prior art. Therefore, the sewing machine 1 can shorten the upper thread and lower thread cut ends remaining on the cloth after cutting, as compared with the case where the upper thread and the lower thread are cut at a position away from the needle hole 90.

  At the time of sewing, the upper thread and the lower thread pass through the needle hole 90 and extend below the needle plate 9. In the protection member 175, the extension length of the protection surface 176 is not less than the diameter D of the needle hole 90. Therefore, even if the upper thread and the lower thread move within the range of the needle hole 90, the protection member 175 can reliably prevent the upper thread and the lower thread from touching the blade portion 114 of the fixed blade 110.

  The thread gripping member 160 and the thread presser member 180 can sandwich and hold the end of the upper thread at the start of sewing. The protection member 175 is provided integrally with the thread gripping member 160. The protection member 175 is positioned at the protection position when the thread gripping member 160 and the thread presser member 180 are loosened after holding the end of the upper thread. Therefore, since the sewing machine 1 can hold the upper thread and move the protection member 175 only by driving the thread gripping member 160, it is not necessary to provide a separate movement mechanism for the protection member 175.

  Since the arm portion 170 is bent in the vertical direction by the first bent portion 171, the protection member 175 can be disposed in a state closer to the blade portion 114 of the fixed blade 110 at the protection position. Therefore, the protective member 175 can shorten the distance between the fixed blade 110 and the blade portion 114, and can more reliably prevent the upper thread and the lower thread from touching the blade portion 114 of the fixed blade 110 during sewing. The possibility of cutting can be further reduced.

  When the thread gripping member 160 is located at the capture position, the arm portion 170 does not overlap with the formation position of the needle hole 90 in the vertical direction. Therefore, the arm portion 170 is unlikely to interfere with the upper thread and the lower thread that pass through the needle hole 90. Since the arm portion 170 does not apply a load to the upper thread and the lower thread, the sewing machine 1 can be sewn smoothly.

  The thread cutting motor 25 that applies a driving force to the movable blade 120 also applies a driving force to the thread gripping member 160. Therefore, the sewing machine 1 does not need to be separately provided with a thread trimming motor 25 for driving the thread gripping member 160.

  Since the protection member 175 is moved away from the path of the movable blade 120 when the movable blade 120 is driven, the range in which the thread gripping member 160 rotates is larger than the configuration without the conventional protection member 175. The thread presser member 180 rotates following the thread gripping member 160. Since the thread presser member 180 includes the second contact part 192 that is recessed on the opposite side of the pin 166 from the first contact part 191, the thread presser member when the thread gripping member 160 is positioned on the separated position side from the release position. The amount of rotation of the member 180 can be suppressed. Therefore, the sewing machine 1 does not need to ensure a large area for the thread presser member 180 to rotate below the needle plate 9.

  The present invention is not limited to the above embodiment, and various modifications can be made. The protective member 175 is disposed at a position where the end on the side of the needle hole 90 intersects the virtual straight line V1 at the protective position, but is not limited thereto. For example, as shown in FIG. 13, the protection member 275 may be disposed at a position where the end on the needle hole 90 side is in contact with the virtual straight line V <b> 1 in the protection position. In this case, the blade 114 does not cut into the yarn T even if the yarn T comes into contact with the blade portion 114, and therefore does not cut the yarn T. If the protection member 275 is disposed close to the needle hole 90, the fixed blade 110 can be disposed such that the blade portion 114 is closer to the needle hole 90. The protection member 275 can widen the range in which the thread T can move according to the sewing state below the needle plate 9.

  In the present embodiment, the length L in the extending direction of the protective surface 176 of the protective member 175 is shorter than the blade span length of the blade portion 114 of the fixed blade 110. Not limited to this, the length L in the extending direction of the protection member 175 may be equal to or longer than the blade span length of the blade portion 114 of the fixed blade 110 as long as it is equal to or larger than the diameter D of the needle hole 90. As the length L in the extending direction of the protection member 175 is longer, the protection member 175 can more reliably prevent the upper thread and the lower thread from coming into contact with the blade portion 114 of the fixed blade 110.

  The protective surface 176 of the protective member 175 extends in the extending direction, but is not limited thereto. For example, as shown in FIG. 14, the protective surface 376 of the protective member 375 may extend in an arc shape that matches the shape of the needle hole 90. The protective surface 376 can be positioned between the upper thread and the lower thread extending below the needle plate 9 and the blade portion 114 of the fixed blade 110. Therefore, the protection member 375 can more reliably prevent the upper thread and the lower thread from coming into contact with the blade portion 114 of the fixed blade 110.

  In the present embodiment, the protection member 175 is provided integrally with the thread gripping member 160, but is not limited thereto. For example, the protection member 175 may be provided integrally with the thread presser member 180 via the arm portion 170. For example, the protective member 175 may be provided separately from the thread gripping member 160 and moved between the protective position and the retracted position. For example, the thread clamp member 180 may not be provided, and the thread gripping member 160 may move the protection member 175 between the protection position and the retracted position.

  The arm portion 170 may not have the first bent portion 171 and the second bent portion 172. The thread trimming motor 25 may also apply a driving force to the thread presser member 180 to drive the thread retainer member 180 independently of the thread gripping member 160. The driving source of the thread gripping member 160 may be provided individually instead of the thread cutting motor 25. Although the second contact portion 192 of the thread presser member 180 is provided in a recessed shape having a step with respect to the first contact portion 191 in plan view, the present invention is not limited thereto. For example, the second contact portion 192 may be provided in an arc shape that is smoothly continuous from the first contact portion 191.

  In the above embodiment, the blade portion 114 corresponds to the “blade edge” of the fixed blade of the present invention. The blade portion 124 corresponds to the “blade edge” of the movable blade of the present invention. The thread cutting motor 25 corresponds to the “power source” of the present invention. The one end 161 corresponds to the “first end” of the present invention. The one end 181 corresponds to the “second end” of the present invention. The pin 166 corresponds to the “projection” of the present invention.

1 Sewing machine 7 Sewing needle 9 Needle plate 25 Thread trimmer motor 90 Needle hole 110 Fixed blade 114, 124 Blade portion 120 Movable blade 160 Thread gripping member 161, 181 One end portion 165 Thread hole 166 Pin 170 Arm portion 171 First bent portion 172 First Two bent portions 175, 275, 375 Protective member 180 Yarn presser member 190 Contact portion 191 First contact portion 192 Second contact portion

Claims (7)

A fixed blade that is provided on the lower side of a needle plate having a needle hole through which a sewing needle passes, and has a cutting edge disposed toward the needle hole;
A movable blade that is provided on the lower side of the needle plate so as to be horizontally rotatable and capable of reciprocating along a path where the blade edge intersects the blade edge of the fixed blade;
A power source for applying a driving force to the movable blade and reciprocating the movable blade;
With
When the movable blade is driven by the power source, the upper thread and the lower thread are captured by the movable blade, and the upper thread and the lower thread are cut by crossing the blade edge of the movable blade and the blade edge of the fixed blade. In the sewing machine
A protective member positioned at a lower protective position when the movable blade is not driven and positioned at a retracted position away from the needle hole with respect to the blade edge of the fixed blade when the movable blade is driven;
When the protective member is located at the protective position, in the cross section including the fixed blade, the protective member, and the center position of the needle hole, the end portion of the protective member on the needle hole side is the needle hole side. A sewing machine that contacts or intersects an imaginary straight line connecting an edge on a side where a protective member is located and a blade edge of the fixed blade. The cutting edge of the fixed blade extends in the extending direction perpendicular to the center line of the needle hole,
2. The sewing machine according to claim 1, wherein an end of the protective member on the side of the needle hole extends along the extending direction and has a length equal to or greater than a diameter of the needle hole. A preparation position in which a thread hole through which the upper thread passes is provided at a first end portion so as to be horizontally rotatable under the needle plate, and the thread hole is positioned below the needle hole at the start of sewing; A thread gripping member that moves between the preparation position and a separation position that is located at a position away from the needle hole;
The thread gripping member is provided below the needle plate so as to be horizontally rotatable, and has a second end portion capable of holding the upper thread between the first end portion of the thread gripping member and holding the upper thread. A thread presser member that moves to a position where the second end portion overlaps with the thread hole in the vertical direction and sandwiches the upper thread,
With
The thread gripping member and the protection member are integrally provided via an arm portion extending from the first end in a direction opposite to the direction in which the thread gripping member moves from the preparation position toward the separation position,
When the thread gripping member moves to a capture position between the preparation position and the separation position, the thread hole moves to a position overlapping the second end portion in the vertical direction, and the capture position and the separation position The thread hole moves to a position away from the second end and loosens the upper thread,
The sewing machine according to claim 1 or 2, wherein the protection member is located at the protection position when the thread gripping member is moved to the release position. The thread gripping member is located below the fixed blade,
4. The sewing machine according to claim 3, wherein the arm portion is bent in a vertical direction, and has a first bent portion that disposes the protection member above the first end portion. When the thread gripping member is located at the capture position, the rotation center of the protection member and the first end, and the arm part and the thread gripping member are opposite to each other with the needle hole forming position in between. Located in
5. The sewing machine according to claim 3, wherein the arm portion has a second bent portion that is bent in a horizontal direction on a side opposite to a rotation center of the thread gripping member.   6. The power source according to claim 3, wherein the power source applies a driving force to the thread gripping member and moves the thread gripping member between the preparation position and the separation position. sewing machine. The thread gripping member includes a protruding portion that protrudes in the vertical direction between the rotation center of the thread gripping member and the first end.
The thread presser member is a side surface on which the protruding portion abuts between the rotation center of the thread presser member and the second end when the thread gripping member moves from the preparation position to the release position. A contact portion,
The protruding portion contacts the contact portion when the thread gripping member moves from the preparation position to the release position, and rotates the thread presser member in the same direction as the thread gripping member.
The contact portion is
A first abutting portion with which the protrusion abuts when the thread gripping member is located between the preparation position and the release position;
A second abutting portion that abuts the projecting portion when the thread gripping member is located on the side of the separated position from the release position, and that is recessed to the opposite side of the projecting portion from the first abutting portion;
The sewing machine according to claim 6, comprising:

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