Abstract:
A sewing machine includes a needle bar, a needle bar base, a base frame, a guide member, and a fixing member. A sewing needle is attachable to a lower end portion of the needle bar. The needle bar base is configured to support the needle bar to allow the needle bar to be moved in an up-down direction. A first engagement portion is provided to a lower end portion of the needle bar base. The base frame is configured to swingably support an upper end portion of the needle bar base. A second engagement portion is provided to a lower end portion the base frame. A guide member includes a third engagement portion configured to engage with the first engagement portion and guide movement of the first engagement portion in a predetermined direction and a fourth engagement portion configured to engage with the second engagement portion.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority to Japanese Patent Application No. 2012-072909 filed Mar. 28, 2012, the content of which is hereby incorporated herein by reference. 
     BACKGROUND 
     The present disclosure relates to a sewing machine that allows a clearance between a sewing needle and a hook point of a shuttle to be adjusted. 
     A known sewing machine mainly includes a bed, a pillar, an arm, and a head. The arm is provided with a drive shaft. The drive shaft may be driven by a sewing machine motor. The head is provided with a needle bar base. The needle bar base supports a needle bar. Due to the rotation of the drive shaft, the needle bar may be moved in the up-down direction. The bed is provided with a shuttle. The shuttle may be rotated in accordance with the rotation of a lower shaft, which may be rotated in conjunction with the drive shaft. An upper thread may be supplied to a sewing needle that is attached to the needle bar. A lower thread may be supplied from a bobbin that is housed in the shuttle. The upper thread and the lower thread may be interlaced by the needle bar and the shuttle working in cooperation with each other, thus forming a stitch on a work cloth. 
     A sewing machine is provided with a function to sew zigzag stitching. The zigzag stitching is sewing that is performed while the needle bar is swung left and right. An upper end portion of the needle bar base is swingably supported. The zigzag stitching is performed by moving a lower end portion of the needle bar base in the left-right direction. 
     In order to reliably form a stitch with a sewing machine, it is important to adjust a clearance between a sewing needle and a hook point of the shuttle. The clearance between the sewing needle and the hook point of the shuttle is hereinafter referred to as the needle gap. The needle gap may be adjusted for a left needle gap and a right needle gap. The left needle gap is a clearance between the sewing needle and the hook point when the sewing needle is in a left needle drop position (a left reference line position). The left reference line position is a leftmost needle drop position in the greatest zigzag width. The right needle gap is a clearance between the sewing needle and the hook point when the sewing needle is in a right needle drop position (a right reference line position). The right reference line position is a rightmost needle drop position in the greatest zigzag width. For example, in a known sewing machine, a plate is fixed to an arm by two screws. By displacing an attachment position of the plate in relation to the arm, it is possible to adjust the left and right needle drop positions. By adjusting the left and right needle drop positions, it is possible to adjust the needle gaps. 
     SUMMARY 
     In the above-described known sewing machine, a procedure when adjusting the needle gaps is as follows. First, the two screws fixing the plate to the arm may be loosened, such that the plate can be freely moved. The attachment position of the plate may be changed. The plate may be once more fixed to the arm by the screws. Thus, for example, in a case where the right needle gap is adjusted after the left needle gap has been adjusted, it is necessary to adjust the right needle gap while maintaining the adjusted left needle gap unchanged. As a result, an operation to adjust the needle gaps may be difficult. 
     Embodiments of the broad principles derived herein provide a sewing machine in which, after one of a left and a right needle gaps has been adjusted, the adjusted one of the needle gaps remains unchanged. 
     Embodiments provide a sewing machine that includes a needle bar, a needle bar base, a base frame, a guide member, and a fixing member. A sewing needle is attachable to a lower end portion of the needle bar. A needle bar base is configured to support the needle bar to allow the needle bar to be moved in an up-down direction. A first engagement portion is provided to a lower end portion of the needle bar base. A base frame is configured to swingably support an upper end portion of the needle bar base. A second engagement portion is provided to a lower end portion the base frame. A guide member includes a third engagement portion and a fourth engagement portion. The third engagement portion is configured to engage with the first engagement portion and guide movement of the first engagement portion in a predetermined direction. The fourth engagement portion is configured to engage with the second engagement portion. A fixing member is configured to fix the guide member to the base frame. When the needle bar base is in a reference position, a first reference line of the first engagement portion, a second reference line of the second engagement portion, and a third reference line of the fourth engagement portion are in a same straight line, and the guide member is configured to be swingable about the same straight line in a state in which fixing of the fixing member with respect to the base frame is loosened. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiments will be described below in detail with reference to the accompanying drawings in which: 
         FIG. 1  is a perspective view of a sewing machine; 
         FIG. 2  is a perspective view showing an internal configuration of a left end portion of the sewing machine including a head; 
         FIG. 3  is a perspective view of a needle bar module; 
         FIG. 4  is an exploded perspective view of a needle bar support mechanism; 
         FIG. 5  is a perspective view of a base holder; 
         FIG. 6  is a perspective view of a needle bar base; 
         FIG. 7  is a perspective view of a lower side of a guide member, as seen from the front and right; 
         FIG. 8  is a perspective view of an upper side of the guide member, as seen from the front and right; 
         FIG. 9  is a diagram showing a state, as seen from above, of a relationship between the guide member and a left needle gap when the needle bar is positioned in a left reference line position; and 
         FIG. 10  is a diagram showing a state, as seen from above, of a relationship between the guide member and a right needle gap when the needle bar is positioned in a right reference line position. 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, a sewing machine  1  according to an embodiment will be explained with reference to the drawings. 
     A configuration of the sewing machine  1  will be explained with reference to  FIGS. 1 and 2 . In the following explanation, the lower right side, the upper left side, the lower left side, the upper right side, the upper side, and the lower side of  FIG. 1  are respectively the front side, the rear side, the left side, the right side, the upper side, and the lower side of the sewing machine  1 . More specifically, a direction in which a pillar  3 , which is described below, extends is the up-down direction of the sewing machine  1 . A longitudinal direction of a bed  2  and an arm  4  is the left-right direction of the sewing machine  1 . An explanation of the structural members of the sewing machine  1  shown in  FIGS. 3 to 10  is made with reference to the front-rear direction and the left-right direction when the structural members are attached to the sewing machine  1 . 
     As shown in  FIG. 1 , the sewing machine  1  is provided with the bed  2 , the pillar  3 , the arm  4 , and a head  5 . The bed  2  extends in the left-right direction. A horizontal shuttle  8  (refer to  FIG. 2 ) and the like are provided in the interior of the left portion of the bed  2 . The pillar  3  extends upward from the right end of the bed  2 . A sewing machine motor (not shown in the drawings) and the like are provided in the interior of the pillar  3 . The arm  4  extends to the left from the upper side of the pillar  3  such that the arm  4  faces the upper surface of the bed  2 . A drive shaft  51  (refer to  FIG. 2 ) and the like are provided in the interior of the arm  4 . The head  5  is provided on the left side of the arm  4 . A needle bar module  10  (refer to  FIG. 2 ) and the like are provided in the interior of the head  5 . The needle bar module  10  includes a needle bar support mechanism  100 , which will be described below. The needle bar support mechanism  100  includes a needle bar  110  that can be moved in the up-down direction. The needle bar  110  is exposed from the lower side of the head  5 , and extends downward. A sewing needle  101  may be attached to the lower end of the needle bar  110 . 
     As shown in  FIG. 2 , a needle plate  11  is provided on the upper portion of the bed  2 . The needle plate  11  has a needle hole  12  that is positioned directly below the needle bar  110 . The sewing needle  101  that is attached to the needle bar  110  can be inserted through the needle hole  12 . The horizontal shuttle  8  is provided below the needle plate  11 . The horizontal shuttle  8  may house a bobbin (not shown in the drawings) on which a lower thread (not shown in the drawings) is wound. A lower shaft  21  may be rotated in conjunction with the drive shaft  51 . The horizontal shuttle  8  may be rotated in the horizontal direction in accordance with the rotation of the lower shaft  21 . The horizontal shuttle  8  includes a hook point  9  (refer to  FIG. 9 ). The leading end portion of the hook point  9  faces a peripheral direction of the horizontal shuttle  8 . The hook point  9  may seize a loop of an upper thread. When the needle bar  110  is lowered by a needle bar drive mechanism  16 , the sewing needle  101  attached to the needle bar  110  may approach the hook point  9  of the horizontal shuttle  8 . A feed dog  13  is provided under the needle plate  11 . The feed dog  13  may move a work cloth by a predetermined feed distance. 
     A configuration of the needle bar module  10 , which is provided on the head  5 , will be explained with reference to  FIGS. 2 to 8 . The needle bar module  10  shown in  FIGS. 2 and 3  is a module that is formed by integrating the needle bar support mechanism  100 , the needle bar drive mechanism  16 , a thread take-up drive mechanism  17 , and a presser foot lifting mechanism  18 . The needle bar support mechanism  100  supports the needle bar  110 . The sewing needle  101  may be attached to the needle bar  110 . The needle bar drive mechanism  16  may drive the needle bar  110  to reciprocate in the up-down direction. The thread take-up drive mechanism  17  may drive a thread take-up lever  170  (refer to  FIG. 3 ). The presser foot lifting mechanism  18  may raise and lower a presser bar  180  (refer to  FIG. 3 ). The needle bar module  10  is fixed to a machine frame  6  inside the head  5 . The rotation of the drive shaft  51  may be transmitted to the needle bar drive mechanism  16  and the thread take-up drive mechanism  17 , so that the needle bar drive mechanism  16  and the thread take-up drive mechanism  17  may be driven. 
     As shown in  FIG. 3  to  FIG. 5 , a base holder  120  of the needle bar support mechanism  100  is formed of a metal plate that extends in the up-down direction. A support shaft  173 , which extends in the left-right direction, is fixed to the base holder  120 , slightly above the center of the base holder  120  in the up-down direction. The length of the support shaft  173  is longer than the length, in the left-right direction, of the base holder  120 . The support shaft  173  protrudes from the base holder  120  in the left and right directions. The left end portion of the support shaft  173  is fixed to the machine frame  6  by a presser plate  175  and a screw  174  (refer to  FIG. 2 ). Although not shown in the drawings, the right end portion of the support shaft  173  is also fixed to the machine frame  6  in the same manner. Although not shown in the drawings, the lower end portion of the base holder  120  is fixed to the machine frame  6  such that an inclination (as seen from the side) of the base holder  120  can be adjusted. In a case where the screw  174  that fixes the support shaft  173  is slightly loosened, the base holder  120  may be swung with the support shaft  173  as the center of rotation, in the side view. Thus, the base holder  120  may be fixed to the machine frame  6  after the inclination of the base holder  120 , namely the posture of the base holder  120  in relation to the machine frame  6 , has been adjusted. 
     A support portion  122  is provided on the lower end portion of the base holder  120 . The support portion  122  is a portion that extends toward the front from the lower edge of the base holder  120 . A support hole  185  is formed in a position close to the right side of the support portion  122 . The support hole  185  penetrates the support portion  122  in the up-down direction. A boss portion  123  is provided in a position close to the front left side of the support portion  122 . The boss portion  123  is a portion that protrudes downward from the support portion  122  in a cylindrical shape. A central line of the boss portion  123  is denoted by Q. A screw hole  129  is formed in a position close to the rear left side of the support portion  122 . The screw hole  129  penetrates the support portion  122  in the up-down direction. 
     As shown in  FIG. 3 , the presser bar  180  that extends in the up-down direction is inserted through the support hole  185  (refer to  FIG. 4 ). A presser foot  181  is provided on the lower end portion of the presser bar  180 . A support piece  182  is attached to the upper portion of the base holder  120 . The upper end portion of the presser bar  180  is supported by the support piece  182 . In this manner, the presser bar  180  is supported on the base holder  120  such that the presser bar  180  can be moved in the up-down direction. A presser spring (not shown in the drawings) is provided around the presser bar  180 . The presser bar  180  is biased downward by the biasing force of the presser spring. A lever shaft  184  is provided on the lower right portion of the base holder  120 . The lever shaft  184  protrudes toward the front. A presser lever  183  is supported such that the presser lever  183  may be pivoted in relation to the lever shaft  184 . When the presser lever  183  is operated, the presser bar  180  and the presser foot  181  are raised and lowered. The presser foot lifting mechanism  18  includes the presser bar  180 , the presser spring, and the presser lever  183 , which are described above. 
     The thread take-up lever  170  and the thread take-up drive mechanism  17  are disposed at the right of the base holder  120 . The thread take-up lever  170  and the thread take-up drive mechanism  17  are known mechanisms and are briefly explained here. A thread take-up crank  52  is fixed to the left end portion of the drive shaft  51 . The thread take-up crank  52  may be rotated integrally with the drive shaft  51 . The thread take-up crank  52  may be rotated in accordance with the rotation of the drive shaft  51 , so that the thread take-up drive mechanism  17  may be driven. By the driving of the thread take-up drive mechanism  17 , the thread take-up lever  170  may be moved in the up-down direction in synchronization with the reciprocating motion in the up-down direction of the needle bar  110 . 
     As shown in  FIGS. 4 and 5 , a support shaft  124  is provided on an upper end portion  118  of the base holder  120 . The support shaft  124  extends toward the front. The support shaft  124  pivotably supports a needle bar base  130  that will be described below. The support shaft  124  is provided with a base end portion  125 , a trunk portion  126 , and a leading end portion  127 . The trunk portion  126  is formed having a smaller diameter than that of the base end portion  125 . The trunk portion  126  extends longer in the front-rear direction. The leading end portion  127  is formed having a diameter that is smaller than a diameter of the trunk portion  126 . A male screw  128  is formed on the leading end portion  127 . The male screw  128  is a right-hand thread screw. Further, an attachment portion  119  is formed on the base holder  120 . The attachment portion  119  is a portion that extends toward the front from the upper left portion of the base holder  120 . A plate spring  150 , which will be described below, is fixed to the attachment portion  119 . 
     As shown in  FIGS. 4 and 6 , the needle bar base  130  is formed of a metal plate that extends in the up-down direction. A through hole  131  is formed in an upper end portion  137  of the needle bar base  130 . The through hole  131  penetrates the upper end portion  137  in the front-rear direction. The inner diameter of the through hole  131  is slightly larger than the outer diameter of the trunk portion  126  of the support shaft  124 . The through hole  131  is formed in a tapered shape by chamfering, such that the through hole  131  becomes narrower from the front toward the rear. Further, the needle bar base  130  includes a pressing portion  132 . The pressing portion  132  is a portion that extends downward from the upper rear end portion of the needle bar base  130 . A groove  139  is formed in the pressing portion  132 . The groove  139  is generally an inverted U-shape. The width of the groove  139  in the left-right direction is slightly larger than the outer diameter of the trunk portion  126  of the support shaft  124 . The trunk portion  126  fits into the groove  139 . 
     The needle bar base  130  includes a support portion  133 . The support portion  133  is a portion that extends toward the rear from the lower edge of the needle bar base  130 . A hole  134  (refer to  FIG. 3 ) is formed in a position toward the right side of the support portion  133 . The hole  134  penetrates the support portion  133  in the up-down direction. A left portion of the support portion  133  protrudes further to the rear than a right portion of the support portion  133 . A cylindrical pin  135  is provided on the rear end portion of the left portion of the support portion  133 . The pin  135  protrudes upward from the support portion  133 . A central line of the pin  135  is denoted by P. A direction in which the pin  135  extends is parallel to the needle bar  110 . The outer diameter of the pin  135  is generally the same as the size of a groove width of a long groove  191  that is provided in the guide member  190 , which will be described below. 
     The needle bar base  130  includes a bent portion  136 . The bent portion  136  is a portion that extends to the rear from a portion of the needle bar base  130  above the center of the needle bar base  130  in the up-down direction such that the bent portion  136  is parallel to the support portion  133 . A hole (not shown in the drawings) having a same inner diameter as a diameter of the hole  134  is formed in the bent portion  136 . As shown in  FIG. 3 , the needle bar  110  is inserted into and supported by the hole  134  and the hole of the bent portion  136 , such that the needle bar  110  may be moved in the up-down direction. An attachment portion  111  is provided on the lower end portion of the needle bar  110 . The sewing needle  101  may be attached to and removed from the attachment portion  111 . 
     As shown in  FIG. 3 , a compression coil spring  155  is mounted around the outer periphery of the trunk portion  126 . The rear end of the compression coil spring  155  is in contact with a stepped portion between the trunk portion  126  and the base end portion  125 . The support shaft  124  is inserted through the through hole  131  of the needle bar base  130  and the groove  139 . In this manner, the needle bar base  130  is supported by the support shaft  124  in a state in which the needle bar base  130  can be rotated around the support shaft  124 . The leading end of the compression coil spring  155  is in contact with the pressing portion  132  of the needle bar base  130 . 
     A disc-shaped adjustment dial  140  is attached to the leading end portion  127  of the support shaft  124 . Although not shown in detail in the drawings, a hole is provided in the center of the adjustment dial  140 . The trunk portion  126  of the support shaft  124  may be inserted through the hole in the adjustment dial  140 . A nut fixing portion (not shown in the drawings) is formed to the front of the adjustment dial  140 . The nut fixing portion is a recessed portion that is formed in a position such that the center of the nut fixing portion is concentric with the center of the hole in the adjustment dial  140 . A nut  141  is fitted into and fixed to the nut fixing portion. A hemispheric contact portion is formed around the periphery of the hole in the adjustment dial  140 . A straight knurl is formed on an outer peripheral surface of the adjustment dial  140 . 
     As shown in  FIGS. 3 and 4 , the support shaft  124  is inserted through the through hole  131  of the needle bar base  130 . The leading end portion  127  of the support shaft  124  is inserted through the hole in the adjustment dial  140 . The male screw  128  formed on the leading end portion  127  is screwed into a female screw of the nut  141 . The contact portion of the adjustment dial  140  is in contact with the tapered surface of the through hole  131  of the needle bar base  130 . At this time, the compression coil spring  155  is pressed in the rearward direction by the pressing portion  132  of the needle bar base  130 , and is compressed in the axial direction of the support shaft  124 . The compression coil spring  155  presses the pressing portion  132  of the needle bar base  130  toward the side of the leading end portion  127 , from the side of the base end portion  125  of the support shaft  124 . In other words, between the base holder  120  and the adjustment dial  140 , the needle bar base  130  is maintained in a state of being biased toward the adjustment dial  140 , due to the biasing force of the compression coil spring  155 . As described above, the male screw  128  is a right-hand thread screw. Thus, when the adjustment dial  140  is rotated in the clockwise direction, the adjustment dial  140  and the needle bar base  130  are moved toward the rear. In contrast, when the adjustment dial  140  is rotated in the anti-clockwise direction, the adjustment dial  140  and the needle bar base  130  are moved toward the front. In this manner, by rotating the adjustment dial  140 , the adjustment dial  140  may be moved in the axial direction of the support shaft  124 . In accordance with the movement of the adjustment dial  140 , the needle bar base  130  may be moved in the axial direction of the support shaft  124 . 
     As shown in  FIG. 3 , the rectangular plate spring  150  is provided on the attachment portion  119  of the base holder  120 . The rear end (the base end) of the plate spring  150  is fixed to the attachment portion  119  by a screw. A leading end portion  152  of the plate spring  150  is in contact with the outer peripheral surface (the straight knurl) of the adjustment dial  140 , and biases the adjustment dial  140  in the rightward direction (in the radial direction). Specifically, the plate spring  150  regulates the rotation of the adjustment dial  140 . 
     As shown in  FIG. 4 , the guide member  190  is provided on the lower surface of the support portion  122  of the base holder  120 . The guide member  190  is formed of a synthetic resin material. As shown in  FIGS. 7 and 8 , the guide member  190  includes a flat plate portion  196 , which is generally L-shaped in a plan view, and a long groove portion  192 . A generally elliptical engaging hole  194  is formed in the flat plate portion  196 . A fixing screw  199  (refer to  FIG. 4 ) is inserted through the engaging hole  194 . The fixing screw  199  is screwed into a screw hole  129  of the support portion  122 . By fastening the fixing screw  199  in the screw hole  129 , the guide member  190  is fixed to the base holder  120 . 
     The guide member  190  includes a protruding portion  195 . The protruding portion  195  is a portion of the flat plate portion  196  that protrudes toward the left. A user may grasp the protruding portion  195  with the user&#39;s fingers. 
     The long groove portion  192  of the guide member  190  protrudes downward from the flat plate portion  196 . The long groove  191  is formed in the center of the long groove portion  192 . The long groove  191  penetrates the long groove portion  192  in the up-down direction (the thickness direction). The long groove  191  has an arc shape that extends in the left-right direction. As will be explained in more detail below, a pin  135  is inserted into and engages with the long groove  191 . The pin  135  (refer to  FIG. 4 ) is provided in the support portion  133  of the needle bar base  130 . The (inner side) dimension of the front-rear direction of the long groove  191  (the direction orthogonal to the extending direction of the long groove  191 ) is generally the same as the outer diameter of the pin  135 . A central line, in the front-rear direction, of the long groove  191  intersects with a central line R of a receiving hole  193 , which will be described below. 
     The receiving hole  193  is formed in the guide member  190 . The receiving hole  193  is positioned, in the upper surface of the guide member  190 , in the vicinity of the left end portion of the long groove  191 . The receiving hole  193  is formed in a circular shape. The central line of the receiving hole  193  is denoted by R. The inner diameter of the receiving hole  193  is generally the same as the outer diameter of the boss portion  123  provided on the support portion  122  of the base holder  120 . The depth (length) of the receiving hole  193  is slightly larger than the height of the boss portion  123 . 
     As shown in  FIG. 4 , when the guide member  190  is fixed to the base holder  120 , the receiving hole  193  fits with the boss portion  123 . At that time, the central line R (refer to  FIG. 7 ) of the receiving hole  193  is aligned with the central line Q (refer to  FIG. 5 ) of the boss portion  123 . 
     When the fixing screw  199  is slightly loosened, the fitted state between the receiving hole  193  and the boss portion  123  may be maintained. There may be a slight gap (allowance) between the fixing screw  199  and the engaging hole  194 . Thus, the guide member  190  may be moved by an amount of the gap. Specifically, in a state in which the fixing screw  199  is slightly loosened, the guide member  190  may be rotated (pivoted) relative to the base holder  120  with the central lines R and Q as the center of rotation. The protruding portion  195  of the guide member  190  may protrude (refer to  FIG. 3 ) further to the lateral side (to the left side) than the support portion  122  of the base holder  120 . When adjusting the needle gap, which is the clearance between the sewing needle  101  and the hook point  9  of the horizontal shuttle  8  (refer to  FIGS. 9 and 10 ), the user may slightly loosen the fixing screw  199 . Then, by grasping and operating the protruding portion  195  with the user&#39;s fingers, the user can easily rotate the guide member  190 . 
     The pin  135 , which is provided on the support portion  133  of the needle bar base  130 , engages with the long groove  191  of the guide member  190  that is fixed to the base holder  120 . The pin  135  may be moved in the left-right direction along the long groove  191  while the pin  135  may not be moved in the front-rear direction. Thus, the needle bar base  130  may be guided in a direction in which the needle bar base  130  may be swung along the long groove  191  with which the pin  135  engages. Further, a range over which the needle bar base  130  may be swung is regulated by the long groove  191 . A needle bar swinging mechanism is a known mechanism and is therefore not illustrated in the drawings and a detailed explanation is omitted here. As shown in  FIG. 2 , a connecting rod  53 , which extends in the left-right direction, is coupled to the front surface of the needle bar base  130 . The needle bar swinging mechanism is provided inside the pillar  3 . The needle bar swinging mechanism may move the connecting rod  53  in the left-right direction, so that the needle bar base  130  may be swung in the left-right direction. 
     As shown in  FIG. 3 , a needle bar holder  163  of the needle bar drive mechanism  16  is provided on a middle portion of the needle bar  110 , in a position between the support portion  133  and the bent portion  136 . The needle bar holder  163  holds the needle bar  110 . The needle bar holder  163  is coupled to the leading end of a crank rod  161 . The crank rod  161  is connected to a needle bar crank  160 . The needle bar crank  160  is coupled, via a connecting pin  162 , to the thread take-up crank  52  (refer to  FIG. 2 ). When the drive shaft  51  (refer to  FIG. 2 ) is rotated, the thread take-up crank  52  is rotated. The needle bar crank  160  may be rotated in accordance with the rotation of the thread take-up crank  52 , and thus the crank rod  161  may be driven. The needle bar crank  160 , the crank rod  161 , and the needle bar holder  163  may work in cooperation with each other, and may convert the rotational movement of the drive shaft  51  into a reciprocating motion in the up-down direction. The needle bar  110  may be moved up and down in this manner. 
     In the sewing machine  1  of the present embodiment, a stitch may be formed on the work cloth by the needle bar  110  and the horizontal shuttle  8  working in cooperation with each other. At that time, the sewing needle  101  is attached to the needle bar  110 . An upper thread loop that is formed in the eye of the sewing needle  101  must be reliably picked up by the hook point  9  of the horizontal shuttle  8 . In a case where the upper thread loop cannot be picked up by the hook point  9 , a skipped stitch may occur in which the stitch is not formed. In this case, the sewing quality may deteriorate. In order to eliminate the skipped stitch, it is necessary to properly adjust the needle gap, which is the clearance between the sewing needle  101  and the hook point  9 . In the sewing machine  1  of the present embodiment, the user may adjust the needle gap by adjusting (rotating) the adjustment dial  140 . The needle bar  110  may be swung in the left-right direction. Thus, it is necessary to adjust the needle gap both when the sewing needle  101  is in the left needle drop position (the left reference line position) and when the sewing needle  101  is in the right needle drop position (the right reference line position). 
     In the present embodiment, it is assumed that the right needle gap is adjusted in the right reference line position after adjusting the left needle gap in the left reference line position. Hereinafter, an operation when adjusting a left needle gap X and a right needle gap Y will be explained with reference to  FIGS. 9 and 10 .  FIG. 9  and  FIG. 10  are diagrams schematically showing relationships between a position of the guide member  190 , a position of the sewing needle  101  (the needle bar  110 ), and a position of the hook point  9  of the horizontal shuttle  8 , when seen from above the sewing machine  1 . In  FIGS. 9 and 10 , a position of the guide member  190  is shown by dotted lines when the guide member  190  is rotated within a rotatable range. The guide member  190  may be rotated within the range of the allowance between the fixing screw  199  and the engaging hole  194 . 
     As shown in  FIG. 9 , the needle bar base  130  may be swung such that a central axial line position of the sewing needle  101  (the needle bar  110 ) may be positioned on a left reference line position A. At that time, the pin  135  is positioned close to the left end of the long groove  191  of the guide member  190 . The central line P of the pin  135  may be aligned with the central line Q of the boss portion  123  and with the central line R of the receiving hole  193  that engages with the boss portion  123 . The guide member  190  may be rotated in relation to the base holder  120  with the central lines R and Q as the center of rotation. Thus, even when the guide member  190  is rotated within the rotatable range, the position of the central line P of the pin  135  does not change. Thus, the position of the needle bar base  130  that is provided with the pin  135  and the position of the sewing needle  101  that is attached to the needle bar  110  do not change, irrespective of the rotation of the guide member  190 . Specifically, in the left reference line position A, even if the guide member  190  is rotated, the position of the sewing needle  101  does not change. As a result, the left needle gap X does not change. 
     The adjustment of the left needle gap X may be performed by rotating the adjustment dial  140  provided on the needle bar support mechanism  100 . When the adjustment dial  140  is rotated, the needle bar base  130  is moved in the front-rear direction. As described above, the pin  135  of the needle bar base  130  is engaged with the long groove  191  of the guide member  190  such that the pin  135  may be moved in the left-right direction while the pin  135  may not be moved in the front-rear direction. In this way, even when the needle bar base  130  is moved in the front-rear direction, the position of the pin  135  in the front-rear direction does not change. As a result, the inclination of the needle bar base  130  may change slightly, generally centering on the position at which the pin  135  and the long groove  191  are engaged with each other. More specifically, the adjustment dial  140  may be moved to the front, in a side view of the needle bar support mechanism  100 . In this case, the upper portion of the needle bar base  130  may incline slightly to the front, generally centering on the position at which the pin  135  and the long groove  191  are engaged with each other. In contrast, the adjustment dial  140  may be moved to the rear. In this case, the upper portion of the needle bar base  130  may incline slightly to the rear, generally centering on the position at which the pin  135  and the long groove  191  are engaged with each other. By changing the inclination of the needle bar base  130  in this manner, the sewing needle  101  attached to the lower end portion of the needle bar  110  (which is supported by the needle bar base  130 ) may be moved. When the adjustment dial  140  is moved toward the front, the sewing needle  101  attached to the needle bar  110  is moved in a direction (to the rear) in which the sewing needle  101  comes closer to the hook point  9 . In contrast, when the adjustment dial  140  is moved toward the rear, the sewing needle  101  is moved in a direction (to the front) in which the sewing needle  101  is separated from the hook point  9 . 
     In actuality, the user may perform the adjustment in a state in which the needle plate  11  is removed. The user may look at the horizontal shuttle  8  from the side of the sewing machine  1 , and thus visually checks the clearance between the sewing needle  101  and the hook point  9  in the left reference line position A. The user may grasp the adjustment dial  140  with the user&#39;s fingers and may rotate the adjustment dial  140 . The adjustment dial  140  can easily be operated from the front face of the sewing machine  1 . As described above, when the adjustment dial  140  is rotated in the clockwise direction, the adjustment dial  140  and the needle bar base  130  are moved to the rear. Thus, the sewing needle  101  may be moved to the front and may separate from the hook point  9 . When the adjustment dial  140  is rotated in the anti-clockwise direction, the adjustment dial  140  and the needle bar base  130  are moved to the front. Thus, the sewing needle  101  may be moved to the rear and may approach the hook point  9 . The left needle gap X between the sewing needle  101  and the hook point  9  may be adjusted by the user rotating the adjustment dial  140  with the user&#39;s fingers in this manner. 
     When the adjustment of the left needle gap X is finished, next, the right needle gap Y may be adjusted. As shown in  FIG. 10 , the needle bar base  130  may be swung such that the central axial line position of the sewing needle  101  (the needle bar  110 ) is positioned on the right reference line position B. At this time, the pin  135  may be positioned close to the right end of the long groove  191  of the guide member  190 . The central line P of the pin  135  may be displaced from the central line Q of the boss portion  123  and the central line R of the receiving hole  193 . 
     The user may slightly loosen the fixing screw  199  and may grasp the protruding portion  195  of the guide member  190  with the user&#39;s fingers to rotate (swing) the guide member  190 . The guide member  190  may be rotated with the central lines Q and R as the center of rotation. By rotating the guide member  190 , the position of the long groove  191  may be changed. The position of the pin  135  may change generally in the front-rear direction in accordance with the change in the position of the long groove  191 . The lower end of the needle bar base  130  may be moved to the front and the rear in accordance with the change in the position of the pin  135 . By the lower end of the needle bar base  130  moving to the front and the rear, the sewing needle  101  attached to the needle bar  110  may approach or separate from the hook point  9 . The user may look at the horizontal shuttle  8  from the side of the sewing machine  1 . While visually checking the clearance between the sewing needle  101  and the hook point  9  in the right reference line position B, the user may rotate the guide member  190  and may adjust the right needle gap Y. 
     By rotating the guide member  190  in this manner, it is possible to perform the adjustment of the right needle gap Y. As described above, even though the guide member  190  is rotated, the left needle gap X does not change. Thus, even while adjusting the right needle gap Y, it is possible to maintain the clearance for the left needle gap X. Then, when the adjustment of the right needle gap Y is finished, the user may tighten the fixing screw  199  and may fix the guide member  190  to the base holder  120 . In this manner, the adjustment of the left needle gap X and the right needle gap Y may be completed. 
     As explained above, in the sewing machine  1  of the present embodiment, the pin  135  of the needle bar base  130  and the long groove  191  of the guide member  190  engage with each other. The guide member  190  may be rotated with respect to the base holder  120  with the central lines Q and R of the boss portion  123  and the receiving hole  193  as the center of rotation. When the needle bar  110  is positioned in the left reference line position A, the central line P of the pin  135 , the central line Q of the boss portion  123  and the central line R of the receiving hole  193  are aligned and are on the same straight line. Thus, even when the guide member  190  is rotated, the position of the central line P does not change. In other words, even when the guide member  190  is rotated, the left needle gap X does not change. On the other hand, in a case where the needle bar  110  is positioned in the right reference line position B, when the guide member  190  is rotated, the central line P of the pin  135  is moved to the front and to the rear. In other words, when the guide member  190  is rotated, the right needle gap Y changes. Thus, after the left needle gap X has been adjusted in the left reference line position A, even when the right needle gap Y is adjusted in the right reference line position B, the left needle gap X does not change. As a result, it is possible to easily perform the adjustment of the left and the right needle gaps. 
     Due to the simple configuration in which the pin  135  of the needle bar base  130  is inserted into the long groove  191  of the guide member  190 , the guide member  190  and the needle bar base  130  engage with each other. Thus, it is possible to lower the cost of the sewing machine  1 . 
     Due to the simple configuration in which the receiving hole  193  of the guide member  190  is fitted with the boss portion  123  of the base holder  120 , the base holder  120  and the guide member  190  engage with each other. Thus, it is possible to lower costs. 
     The protruding portion  195  protrudes from the base holder  120 . The user may therefore grasp the protruding portion  195  with the user&#39;s fingers and may easily rotate the guide member  190 . Thus, it is possible to easily adjust the position of the needle bar  110 . 
     The present disclosure is not limited to the above-described embodiment and various modifications may be made. The guide member  190  is formed of the synthetic resin material. However, the guide member  190  may be formed of a metal material. The long groove  191  penetrates in the thickness direction of the guide member  190 . However, as far as the length of the long groove  191  is sufficient to engage the pin  135 , the long groove  191  need not necessarily penetrate the guide member  190 . 
     In the present embodiment, after the left needle gap X has been adjusted in the left reference line position A, the right needle gap Y may be adjusted in the right reference line position B. However, the sewing machine may be configured such that the left needle gap X can be adjusted in the left reference line position A after the right needle gap Y has been adjusted in the right reference line position B. In this case also, it is possible to easily perform the adjustment of the left and the right needle gaps. 
     The apparatus and methods described above with reference to the various embodiments are merely examples. It goes without saying that they are not confined to the depicted embodiments. While various features have been described in conjunction with the examples outlined above, various alternatives, modifications, variations, and/or improvements of those features and/or examples may be possible. Accordingly, the examples, as set forth above, are intended to be illustrative. Various changes may be made without departing from the broad spirit and scope of the underlying principles.