Patent Application
20130255556
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.
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.
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.
Embodiments will be described below in detail with reference to the accompanying drawings in which:
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
As shown in
As shown in
A configuration of the needle bar module 10, which is provided on the head 5, will be explained with reference to
As shown in
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
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
As shown in
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
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
As shown in
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
As shown in
As shown in
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'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
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
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
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
As shown in
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
As shown in
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'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'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
The user may slightly loosen the fixing screw 199 and may grasp the protruding portion 195 of the guide member 190 with the user'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'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.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2012-072909 | Mar 2012 | JP | national |
