Sewing machine, adjustment method, and sensor unit

Abstract

This invention provides a sewing machine, an adjustment method, and a sensor unit that contribute to easily adjusting the needle gap. [Solution] The sewing machine comprises a bobbin mechanism 30, a first sensor 61, a second sensor 62, and a display unit. The bobbin mechanism 30 comprises a movable body 32. The movable body 32 has a pointed tip 352. The bobbin shaft extends in the left-right direction and rotates the movable body 32 in a rotational direction around itself. A set screw 332 allows adjustment of the position of the movable body 32 in the axial direction of the bobbin shaft. The first sensor 61 is located on one side in the axial direction relative to the sewing needle 11 which is positioned at the meeting point. The first sensor 61 detects the amount of axial displacement of the sewing needle 11. The second sensor 62 detects the amount of axial displacement of the movable body 32. The display unit displays information based on the amount of displacement of the movable body 32 detected by the second sensor 62, based on the amount of displacement detected by the first sensor 61.

Description

Technical Field

[0001] The present invention relates to a sewing machine, an adjustment method, and a sensor unit.

Background Art

[0002] The sewing machine includes a sewing needle and a full-rotation hook. The sewing needle is driven by a sewing machine motor via a main shaft. The full-rotation hook cooperates with the sewing needle to catch a thread loop. The sewing machine described in Patent Document 1 includes a position adjustment mechanism and a hook stopper. The position adjustment mechanism adjusts the position of the hook shaft of the full-rotation hook in the axial direction. The hook stopper engages with an engaging portion of the inner hook of the full-rotation hook to restrict rotation of the inner hook. The sewing machine is configured such that the hook stopper can move in the axial direction integrally with the full-rotation hook. The user performs the needle gap adjustment work by moving the full-rotation hook and the hook stopper integrally. The needle gap refers to the gap dimension between the hook tip and the sewing needle.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of Invention

Problems to be Solved by the Invention

[0004] According to the above sewing machine, there is variation in the user's adjustment of the needle gap. Adjustment of the needle gap is difficult for the user. Therefore, adjustment of the needle gap is often entrusted to skilled workers.

[0005] An object of the present invention is to provide a sewing machine, an adjustment method, and a sensor unit that contribute to facilitating the adjustment of the needle gap.

Means for Solving the Problems

[0006] The sewing machine according to the present invention includes a needle bar that is movable in the vertical direction and can have a sewing needle attached to its tip, The sewing machine is characterized by comprising: a bobbin mechanism having a movable body with a pointed tip for capturing the upper thread inserted into the sewing needle mounted on the needle bar; a bobbin shaft having an axis extending in a direction intersecting the vertical direction and rotating the movable body in a rotational direction about the axis; a position adjustment mechanism capable of adjusting the position of the movable body in the axial direction of the bobbin shaft; a bed section housing the bobbin mechanism, the bobbin shaft, and the position adjustment mechanism; a first sensor positioned on one side in the axial direction with respect to the sewing needle, which is positioned at the meeting position which is the position of the sewing needle at the timing when the pointed tip captures a loop formed in the upper thread, and which detects the amount of axial displacement of the sewing needle; a second sensor that detects the amount of axial displacement of the movable body; an arm section supporting the first and second sensors and fixed to the bed section; and a notification unit that notifies information based on the amount of displacement of the movable body detected by the second sensor based on the amount of displacement of the movable body detected by the first sensor. The user of the sewing machine can confirm the positional relationship between the pointed tip of the movable body and the sewing needle based on the amount of displacement of the movable body detected by the second sensor. Therefore, the user can precisely adjust the positional relationship between the tip of the movable part and the sewing needle.

[0007] The sewing machine according to the present invention includes a control unit, which may perform a determination process to determine the reference position of the movable body when the second sensor detects the amount of displacement of the movable body, based on the amount of displacement of the sewing needle detected by the first sensor when the tip of the needle is in contact with the sewing needle, and an output process to output information based on the amount of displacement of the movable body detected by the second sensor to the notification unit, based on the reference position determined in the determination process. When the tip of the needle contacts the sewing needle, the sewing needle bends and displaces. The first sensor detects the amount of axial displacement of the sewing needle. The control unit determines the reference position of the movable body based on the amount of displacement of the sewing needle detected by the first sensor. The reference position is the reference position of the movable body when the second sensor detects the amount of displacement of the movable body. Based on the reference position determined in the determination process, the control unit outputs information based on the amount of displacement of the movable body detected by the second sensor to the notification unit. Therefore, the user of the sewing machine can easily confirm the positional relationship between the sewing needle and the tip of the movable body, which are positioned at the meeting point, using the outputted information.

[0008] In the sewing machine according to the present invention, the information is information on the length of the needle gap, which is the gap between the sewing needle and the tip of the needle, and the output process may be a process of outputting the information to a display unit. The user can check the needle gap length information displayed on the display unit. Therefore, the user can easily check the positional relationship between the sewing needle positioned at the meeting point and the tip of the movable body.

[0009] The movable body of the sewing machine according to the present invention is located on the same axis as the bobbin shaft and has a shaft that protrudes toward one side in the axial direction. The first sensor has a first contact surface that contacts the sewing needle positioned at the meeting position from one side in the axial direction and detects the amount of axial displacement of the sewing needle. The second sensor has a second contact surface that contacts the tip of the shaft from one side in the axial direction and detects the amount of axial displacement of the movable body. The first sensor can detect the amount of axial displacement of the sewing needle by bringing its first contact surface into contact with the sewing needle. The second sensor can detect the amount of axial displacement of the movable body by bringing its second contact surface into contact with the tip of the shaft of the movable body.

[0010] The first sensor of the sewing machine according to the present invention is rotatable about a first rotation axis intersecting the axial direction and comprises a first detector having a first contact surface and a first detection unit that detects the rotational position of the first detector rotating about the first rotation axis when the sewing needle contacts the first contact surface. The second sensor may also comprise a second detector having a second contact surface and being rotatable about a second rotation axis intersecting the axial direction and a second detection unit that detects the rotational position of the second detector rotating about the second rotation axis when the tip of the shaft contacts the second contact surface. The first sensor converts the displacement of the sewing needle into the rotation amount of the first detector and detects the rotational position of the first detector with the first detection unit. Therefore, the first sensor can accurately detect the displacement of the sewing needle regardless of the size or shape of the sewing needle, compared to a configuration that directly detects the displacement of the sewing needle. The second sensor converts the displacement of the axis of the movable body into the rotation amount of the second detector and detects the rotational position of the second detector with the second detection unit. Therefore, compared to a configuration that directly detects the displacement of the movable body, the second sensor can accurately detect the displacement of the movable body regardless of the size or shape of the sewing needle.

[0011] The tip of the sewing machine according to the present invention may be able to contact the sewing needle from the other side in the axial direction. The tip contacts the sewing needle from the other side. The sewing needle bends to one side. Therefore, the first sensor can detect the amount of bending of the sewing needle as a displacement.

[0012] The adjustment method according to the present invention is an adjustment method for adjusting the position of the movable body relative to the sewing needle in the sewing machine according to any one of claims 1 to 6, comprising: a first step of positioning the sewing needle at the meeting position; a second step of fixing the sensor unit having the first sensor, the second sensor, and the arm portion to the bed portion; and after the sewing needle has been positioned at the meeting position by the first step and the sensor unit has been fixed to the bed portion by the second step, moving the movable body toward the sewing needle from the other side in the axial direction relative to the sewing needle. The invention is characterized by comprising: a third step of moving the movable body as described in the third step; a fourth step of detecting the amount of displacement of the sewing needle with the first sensor while the tip of the movable body moving as described in the third step is in contact with the sewing needle and the sewing needle is bent; a fifth step of determining the reference position of the movable body when the second sensor detects the amount of displacement of the movable body based on the amount of displacement of the movable body detected in the fourth step; and a sixth step of outputting the information based on the amount of displacement of the movable body detected by the second sensor to the notification unit based on the reference position determined in the fifth step. Therefore, the user of the sewing machine can obtain the effects described in any of claims 1 to 6.

[0013] The sensor unit according to the present invention is a sensor unit used in the sewing machine described in any one of claims 1 to 6, characterized by comprising the first sensor, the second sensor, and the arm portion. Therefore, the user of the sewing machine can obtain the effects described in any one of claims 1 to 6.

[0014] The arm portion of the sensor unit according to the present invention may have a through hole at a position corresponding to the screw hole provided in the bed portion for fixing the needle plate. In order to fix the arm portion to the frame of the sewing machine, the sewing machine does not need to provide a hole in the frame other than the screw hole.

[0015] The sensor unit according to the present invention is a sensor unit used in a sewing machine, comprising: a needle bar that is movable in the vertical direction and to which a sewing needle can be attached at its tip; a bobbin mechanism having a movable body with a pointed tip that catches the upper thread inserted into the sewing needle attached to the needle bar; a bobbin shaft having an axis extending in a direction intersecting the vertical direction and rotating the movable body in a rotational direction about the axis; a position adjustment mechanism that can adjust the position of the movable body in the axial direction of the bobbin shaft; and a bed section housing the bobbin mechanism, the bobbin shaft, and the position adjustment mechanism, wherein the sensor unit is positioned on one side in the axial direction with respect to the sewing needle which is positioned at the meeting position which is the position of the sewing needle at the timing when the pointed tip catches the loop formed in the upper thread, and detects the amount of displacement of the sewing needle in the axial direction. The device is characterized by comprising: a first sensor that emits light; a second sensor that detects the amount of axial displacement of the movable body; a notification unit that notifies information based on the amount of displacement of the movable body detected by the second sensor based on the amount of displacement of the movable body detected by the first sensor; an arm that supports the first sensor and the second sensor and is fixed to the bed; and a control unit that performs a determination process to determine the reference position of the movable body when the second sensor detects the amount of displacement of the movable body based on the amount of displacement of the sewing needle detected by the first sensor when the tip of the needle is in contact with the sewing needle; and an output process that outputs information based on the amount of displacement of the movable body detected by the second sensor to the notification unit based on the reference position determined in the determination process. The tip of the needle comes into contact with the sewing needle. The sewing needle bends and displaces. The first sensor detects the amount of axial displacement of the sewing needle. The control unit determines the reference position of the movable body based on the detected amount of displacement of the sewing needle. The reference position is the reference position when the second sensor detects the amount of displacement of the movable body. The second sensor detects the amount of displacement of the movable body. The control unit outputs information based on the displacement of the movable body to the notification unit, based on the reference position determined in the decision process. Therefore, the sewing machine user can easily confirm the positional relationship between the sewing needle, which is positioned at the meeting point, and the tip of the movable body using the outputted information. Consequently, the user can adjust the positional relationship between the tip of the movable body and the sewing needle with high precision. [Brief explanation of the drawing]

[0016] [Figure 1] It is a perspective view of the sewing machine 1. [Figure 2] It is a partially enlarged view showing a state where the slide plate and the needle plate are removed from the bed portion 2. [Figure 3] It is a perspective view of the sensor unit 50. [Figure 4] It is a diagram showing a state where the sensor unit 50 is fixed to the bed portion 2. [Figure 5] It is a diagram showing a state in which the sewing needle 11 is in contact with the first contact surface 642 of the first sensor 61, and the shaft 351 is in contact with the second contact surface 662 of the second sensor 62. [Figure 6] It is a diagram showing a state where the lower end of the needle bar metal 9 and the base line 101 of the sewing needle 11 are aligned. [Figure 7] It is a diagram showing the positional relationship between the sewing needle 11 and the hook tip 352 arranged at the meeting position. [Figure 8] It is a diagram showing the distance L3 of the needle clearance. [Figure 9] It is a block diagram showing the electrical configuration of the sewing machine 1. [Figure 10] This is the flow of the needle clearance adjustment process. [Figure 11] It is a diagram showing the first screen 111 displayed on the display unit 7. [Figure 12] It is a diagram showing the second screen 112 displayed on the display unit 7. [Figure 13] It is a flowchart of the needle clearance display processing. [Figure 14] It is a perspective view of the display terminal 170. [Figure 15] It is a block diagram showing the electrical configuration of the display terminal 170. [Figure 16] It is a perspective view of the sensor unit 500. [Mode for Carrying Out the Invention]

[0017] An embodiment of the present invention will be described. The description of the present embodiment uses the left-right, front-rear, and up-down directions indicated by arrows in the drawings.

[0018] The structure of sewing machine 1 will be explained. Sewing machine 1, shown in Figure 1, is a lockstitch sewing machine. Sewing machine 1 comprises a bed section 2, a leg column section 3, and an arm section 4. The bed section 2 is installed from above into the opening of the workbench.

[0019] The bed section 2 extends in the left-right direction. The bed section 2 has an opening 14 on the left end side of its upper surface 2A. The opening 14 is roughly U-shaped and opens to the left in a plan view.

[0020] The opening 14 is equipped with a needle plate 15 and a sliding plate 16. The needle plate 15 and sliding plate 16 close the opening 14 from above. The needle plate 15 is located to the right of the sliding plate 16. The user places the fabric on the upper surface 2A of the bed section 2, the needle plate 15, and the sliding plate 16. The sliding plate 16 facilitates access to the bobbin mechanism 30, which will be described later.

[0021] The needle plate 15 has a needle hole, a feed dog hole 151, and two through holes 15A. The needle hole is circular in plan view. Below the needle plate 15 are the feed dogs 13 and the bobbin mechanism 30. The feed dog hole 151 provides a passage for the feed dogs 13 to grasp the fabric and move it forward.

[0022] One of the two through holes 15A is located on the front end side of the needle plate 15. The other through hole is located on the rear end side of the needle plate 15. The two through holes 15A are circular in shape when viewed from above. Two countersunk screws 94 are inserted into the two through holes 15A. The countersunk screws 94 fix the needle plate 15 to the fixed plate 40 of the bed section 2.

[0023] As shown in Figure 2, when the needle plate 15 and slide plate 16 are removed from the opening 14, the frame 26 is exposed through the opening 14. The frame 26 houses the bobbin mechanism 30, bobbin shaft 28, etc. A fixed surface 27 is located on the upper surface of the left wall of the frame 26. The feed dog 13 is fixed to the fixed surface 27.

[0024] The fixing plate 40 is located at the inner periphery of the opening 14. The fixing plate 40 is positioned along the inner periphery of the opening 14. The fixing plate 40 protrudes from the inner periphery of the opening 14 toward the inside of the opening 14. Therefore, the fixing plate 40 is roughly U-shaped, opening to the left in a plan view. The upper surface of the fixing plate 40 is flat.

[0025] The fixed plate 40 is provided with bulging portions 41 and 42. When the fixed plate 40 is viewed from above, the bulging portions 41 and 42 are positioned to sandwich the boiler mechanism 30 from both sides in the front-rear direction. The bulging portion 41 is located in front of the boiler mechanism 30. The bulging portion 42 is located behind the boiler mechanism 30. The bulging portion 41 bulges rearward from the inner periphery of the opening 14. The bulging portion 42 bulges forward from the inner periphery of the opening 14.

[0026] The bulging portion 41 is provided with a screw hole 43. The screw hole 43 penetrates the bulging portion 41 in the vertical direction. The bulging portion 42 is provided with a screw hole 44. The screw hole 44 penetrates the bulging portion 42 in the vertical direction.

[0027] As shown in Figure 1, the through hole 15A on the front side of the needle plate 15 is positioned to correspond to the screw hole 43. The through hole on the rear side of the needle plate 15 is positioned to correspond to the screw hole 44.

[0028] A countersunk screw 94 is fastened to the screw hole 43 through the through hole 15A on the front side of the needle plate 15. A countersunk screw 94 is fastened to the screw hole 44 through the through hole on the rear side of the needle plate 15. Therefore, the needle plate 15 is fixed to the upper surface of the plate to be fixed 40.

[0029] As shown in Figure 1, the leg column 3 extends upward from the right end of the bed section 2. The arm section 4 extends to the left from the upper end of the leg column 3. The lower surface of the arm section 4 faces the upper surface 2A of the bed section 2. The arm section 4 is equipped with a display unit 7 and three operation buttons 8. The display unit 7 is a touch panel.

[0030] The display unit 7 is located in the center of the front of the arm unit 4, in the left-right direction. The three operation buttons 8 are located vertically to the right of the display unit 7. The user can input various instructions to the sewing machine 1 by touch operation while looking at the display unit 7. The user can also input various instructions to the sewing machine 1 using the operation buttons 8.

[0031] A thread stand 20 is located on the left side of the upper surface of the arm section 4. The thread stand 20 protrudes upward. The thread stand 20 guides the path of the upper thread supplied from the spool. The spool is supported by a spool stand installed on the table. The spool supplies the upper thread with appropriate tension.

[0032] The upper shaft and sewing machine motor are located inside the arm section 4. The upper shaft extends in the left-right direction. The upper shaft has an upper shaft pulley at its right end. The upper shaft is connected to the sewing machine motor 19 via the upper shaft pulley. Therefore, the upper shaft rotates when driven by the sewing machine motor 19. The arm section 4 has a sewing machine pulley 6 at its right end. When the sewing machine pulley 6 is rotated, the needle bar 10 moves up and down.

[0033] The arm section 4 is equipped with a head section 5 at its left end. The head section 5 protrudes downward from the left end of the arm section 4. The lower end of the head section 5 faces the upper surface of the needle plate 15.

[0034] The head 5 comprises a needle bar metal 9, a needle bar 10, and a presser foot 12. The needle bar metal 9 is located at the lower end of the head 5. The needle bar metal 9 is roughly cylindrical and protrudes downward. The needle bar 10 protrudes downward from inside the needle bar metal 9. The needle bar 10 is connected to the upper shaft via an up-and-down movement mechanism. The needle bar 10 moves up and down above the needle plate 15 as the upper shaft rotates.

[0035] The sewing needle 11 is attached to the lower end of the needle bar 10. As shown in Figures 7 and 8, the sewing needle 11 has an eyelet 110 and a recessed portion 11A. The eyelet 110 is located near the tip of the sewing needle 11. The eyelet 110 penetrates the sewing needle 11 in the left-right direction. The recessed portion 11A is located directly above the eyelet 110. The recessed portion 11A is a recessed part on the right side of the sewing needle 11. The recessed portion 11A guides the upper thread to pass smoothly through the eyelet 110. The sewing needle 11 moves up and down together with the needle bar 10. The sewing needle 11 holds the upper thread that has been inserted through the eyelet 110.

[0036] As shown in Figure 1, the presser foot 12 is located at the lower end of the head 5. The presser foot 12 holds the fabric on the needle plate 15, fixing the sewing needle 11 in place so that the fabric does not move during sewing.

[0037] The head unit 5 is equipped with, in order from upstream of the path of the upper thread unwound from the spool, a secondary thread tensioner 21, a main thread tensioner 22, a thread guide 23, a balance 24, and a guide hook 25. The secondary thread tensioner 21 is located on the upper right of the front of the head unit 5. The main thread tensioner 22 is located on the front of the head unit 5 and below the secondary thread tensioner 21. The secondary thread tensioner 21 applies tension to the upper thread. The main thread tensioner 22 applies tension to the upper thread.

[0038] The balance beam 24 is located in front of the head 5 and to the left of the auxiliary thread tensioner 21. The balance beam 24 moves up and down driven by the sewing machine motor 19. The thread guide 23 is located below the balance beam 24. The thread guide 23 guides the upper thread, which has passed through the main thread tensioner 22, back towards the balance beam 24. The guide hook 25 guides the upper thread, which has passed through the balance beam 24, towards the needle bar 10.

[0039] As shown in Figure 2, the bed section 2 is equipped with a lower shaft, a fabric feeding mechanism, a bobbin shaft 28, a bobbin mechanism 30, and a thread cutting mechanism inside.

[0040] The lower shaft extends in the left-right direction. The lower shaft has a lower shaft pulley on its right end. A timing belt is stretched between the lower shaft pulley and the upper shaft pulley. The sewing machine motor 19 rotates the upper shaft. When the upper shaft rotates, the lower shaft rotates via the timing belt.

[0041] The lower shaft is equipped with a lower shaft gear. The fabric feeding mechanism is connected to the lower shaft gear. When the lower shaft rotates, the fabric feeding mechanism is driven via the lower shaft gear. Therefore, the fabric feeding mechanism moves the feed dogs up and down in conjunction with the up and down movement of the needle bar 10 to feed the fabric. The thread cutting mechanism cuts the upper and lower threads.

[0042] As shown in Figure 2, the boiler shaft 28 extends in the left-right direction and parallel to the lower shaft. The boiler shaft 28 is rotatably supported inside the bed section 2. The boiler shaft 28 is equipped with a boiler shaft gear at its right end. The boiler shaft gear meshes with the lower shaft gear. Therefore, the boiler shaft 28 rotates in conjunction with the lower shaft.

[0043] The structure of the boiler mechanism 30 will now be described. As shown in Figure 2, the boiler mechanism 30 is connected to the left end of the boiler shaft 28. The boiler mechanism 30 includes a support part 31 and a movable body 32.

[0044] The support portion 31 is a short-axis cylindrical shape extending in the left-right direction. The support portion 31 is fixed to the frame 26. The left end of the boiler shaft 28 is inserted inside the support portion 31. The support portion 31 rotatably supports the left end of the boiler shaft 28.

[0045] The movable body 32 comprises a shaft portion 33 and a boiler 34. The shaft portion 33 and the boiler 34 are integrated. The shaft portion 33 is a short-axis cylindrical shape extending in the left-right direction. The shaft portion 33 has a shaft hole. The shaft hole extends along the axis of the shaft portion 33. The left end of the boiler shaft 28 is inserted into the shaft hole from the right. Therefore, the movable body 32 is movable along the boiler shaft 28.

[0046] The shaft portion 33 is provided with a screw hole 331 on its outer circumferential surface. The screw hole 331 extends radially from the shaft portion 33 and communicates perpendicularly with the shaft hole. A set screw 332 is fastened to the screw hole 331. The tip of the shaft portion of the set screw 332 abuts against the outer circumferential surface of the boiler shaft 28, which is inserted into the shaft hole. Therefore, the shaft portion 33 is fixed to the boiler shaft 28. Therefore, the movable body 32 is fixed to the boiler shaft 28.

[0047] By loosening the set screw 332, the movable body 32 becomes movable along the boiler shaft 28. The user can grasp the movable body 32 and adjust its position in the left-right direction. By tightening the set screw 332, the movable body 32 is fixed to the boiler shaft 28. Therefore, when the boiler shaft 28 rotates, the movable body 32 rotates together with the boiler shaft 28.

[0048] The bobbin 34 is a fully rotating vertical bobbin. The bobbin 34 has an outer bobbin 35 and an inner bobbin. The outer bobbin 35 is located below the needle bar 10. The outer bobbin 35 rotates integrally with the bobbin shaft 28 via the shaft portion 33. When sewing fabric, the rotation direction of the outer bobbin 35 is counterclockwise when viewed from the left. Counterclockwise rotation is left rotation. The outer bobbin 35 is a roughly cylindrical shape with a bottom that opens to the left. The outer bobbin 35 is equipped with a pointed tip 352.

[0049] The pointed tip 352 is located on the outer circumference of the outer casing 35. The pointed tip 352 extends along the circumferential direction of the outer casing 35. The tip of the pointed tip 352 faces downstream in the direction of rotation and is tapered toward the direction of rotation.

[0050] The inner bobbin is a rotating body that fits inside the outer bobbin 35. The inner bobbin can rotate independently of the outer bobbin 35. The inner bobbin is also a roughly cylindrical shape with a bottom that opens to the left. The inner bobbin is equipped with a shaft 351. The shaft 351 is located coaxially with the bobbin shaft 28. The inner bobbin houses and holds the bobbin case. The bobbin case holds the bobbin. The bobbin winds the lower thread. With the inner bobbin fitted inside the outer bobbin 35, the shaft 351 protrudes to the left. The rotation of the inner bobbin is stopped by a bobbin stopper.

[0051] During sewing, the outer bobbin 35 rotates together with the bobbin shaft 28 in accordance with the up-and-down movement of the sewing needle 11. When the sewing needle 11 rises from its lowest point, an upper thread loop is formed in the upper thread. When the sewing needle 11 descends, the needle tip 352 catches the upper thread loop. The position of the sewing needle 11 at the moment when the needle tip 352 catches the upper thread loop is the meeting position.

[0052] The upper thread loop gradually expands as it goes around the bobbin case. Once the upper thread loop has completely gone around the bobbin case, the needle tip 352 releases the upper thread loop. The balance 24 picks up the upper thread loop. The upper thread loop passes through the needle hole of the needle plate 15 upwards, intertwines with the lower thread, and forms a stitch in the fabric.

[0053] Let's explain the needle gap. As shown in Figures 2 and 8, when the sewing machine 1 is viewed from the front, the tip 352 of the bobbin case 34 is positioned to the right of the sewing needle 11. The needle gap is the gap between the outer surface of the sewing needle 11, which is positioned at the meeting point, and the tip of the tip 352. As shown in Figure 8, when the sewing needle 11 moves to the height of the meeting point, the tip 352 faces the recessed portion 11A of the sewing needle 11. Therefore, the needle gap is the gap between the side surface of the recessed portion 11A and the tip of the tip 352. The distance L3 of the gap between the side surface of the recessed portion 11A and the tip of the tip 352 is the length of the needle gap.

[0054] The needle gap length varies depending on the specifications of the sewing machine 1. To adjust the needle gap length, the user attaches the sensor unit 50 to the fixed plate 40 of the bed unit 2. The sewing machine 1 measures the needle gap length with the sensor unit 50 and displays it on the display unit 7. The user can adjust the needle gap length while checking the measured value of the needle gap displayed on the display unit 7.

[0055] Referring to Figure 3, the structure of the sensor unit 50 will be described. The sensor unit 50 comprises an arm portion 52, a first sensor 61, and a second sensor 62.

[0056] The arm section 52 is roughly U-shaped, opening to the right in a plan view. The arm section 52 comprises a base plate 51, a central beam section 521, a first arm 522, and a second arm 523.

[0057] The substrate 51 is oriented with its surface direction in the left-right direction. When viewed from the right, the substrate 51 is roughly rectangular in shape.

[0058] The central beam section 521 is positioned along the upper end of the base plate 51. The central beam section 521 is substantially straight in shape and extends in the front-to-back direction when viewed from above.

[0059] The first arm 522 is substantially straight and extends to the right from the front end of the central beam 521. The first arm 522 is equipped with a fixing plate 524 at its tip. The fixing plate 524 is substantially L-shaped and bends to the rear in a plan view. The fixing plate 524 has a through hole 525 in the center. The through hole 525 penetrates the fixing plate 524 in the vertical direction.

[0060] The second arm 523 is substantially straight and extends to the right from the rear end of the central beam section 521. The second arm 523 is equipped with a fixing plate 526 at its tip. The fixing plate 526 is substantially inverted L-shaped and bends forward in a plan view. The fixing plate 526 has a through hole 527 in the center. The through hole 527 penetrates the fixing plate 526 in the vertical direction.

[0061] The distance between the centers of through holes 525 and 527 is the same as the distance between the centers of screw holes 43 and 44 in the fixed plate 40. Through hole 525 has the same shape as through hole 15A in the needle plate 15. Through hole 527 has the same shape as through hole 15A in the needle plate 15.

[0062] The first sensor 61 is fixed to the upper half of the right side of the circuit board 51 via a mounting plate 55. The mounting plate 55 is a roughly rectangular shape, elongated horizontally in the front-to-back direction when viewed from the right. The first sensor 61 is fixed to the approximate center of the right side of the mounting plate 55 in the left-to-right direction. Both the left and right ends of the mounting plate 55 are fixed to the upper half of the right side of the circuit board 51 with two screws 91, 91.

[0063] The first sensor 61 is a displacement sensor. The first sensor 61 comprises a first detection unit 63, a first detector element 64, and a spring. The first detection unit 63 is substantially rectangular in shape. A cable 63A is connected to the first detection unit 63. The first detector element 64 is substantially T-shaped when viewed from the right. The first detector element 64 comprises a first rotation axis 641 and a first contact surface 642. The first rotation axis 641 extends in the front-rear direction. The first rotation axis 641 is rotatably supported on the right side of the first detection unit 63.

[0064] The first contact surface 642 extends downward from the center of the first rotation axis 641 in the longitudinal direction. The first contact surface 642 is supported facing to the right. The first contact surface 642 has a mountain-like shape that bulges to the right when viewed from the front. The first detector 64 is pivotable in the left-right direction around the first rotation axis 641. A spring constantly biases the first detector 64 to the right. The first detection unit 63 detects the rotational position of the first detector 64 and outputs the detection result to the outside as a displacement amount in the left-right direction.

[0065] The second sensor 62 is fixed to the lower half of the right side of the substrate 51 via a mounting plate 56. The second sensor 62 is also a displacement sensor and has the same structure as the first sensor 61. The second sensor 62 is fixed to the substrate 51 in an up-and-down orientation opposite to that of the first sensor 61.

[0066] The mounting plate 56 is a roughly rectangular shape, elongated horizontally in the front-to-back direction when viewed from the right. The second sensor 62 is fixed to the right side of the mounting plate 56, approximately in the center in the left-to-right direction. Both the left and right ends of the mounting plate 56 are fixed to the lower half of the right side of the circuit board 51 with two screws 92, 92.

[0067] The second sensor 62 comprises a second detection unit 65, a second detector element 66, and a spring. The second detection unit 65 is substantially rectangular in shape. A cable 65A is connected to the second detection unit 65. The second detector element 66 is substantially T-shaped when viewed from the right, upside down. The second detector element 66 comprises a second rotation axis 661 and a second contact surface 662. The second rotation axis 661 extends in the front-rear direction. The second rotation axis 661 is parallel to the first rotation axis 641. The second rotation axis 661 is rotatably supported on the right side of the second detection unit 65.

[0068] The second contact surface 662 extends upward from the center of the second rotation axis 661 in the longitudinal direction. The second contact surface 662 is supported facing to the right. The second contact surface 662 has a mountain-like shape that bulges to the right when viewed from the front. The second detector 66 is pivotable in the left-right direction around the second rotation axis 661. A spring constantly biases the second detector 66 to the right. The second sensor 62 detects the rotational position of the second detector 66 and outputs the detection result to the outside as a displacement amount in the left-right direction.

[0069] Referring to Figure 9, the electrical configuration of the sewing machine 1 will be explained. The sewing machine 1 is equipped with a control unit 70. The control unit 70 is equipped with a CPU 71, ROM 72, RAM 73, EEPROM 74, and I / O 75. The CPU 71 controls the operation of the sewing machine 1. The CPU 71 is connected to the ROM 72, RAM 73, EEPROM 74, and I / O 75 via a bus. The ROM 72 stores various programs, etc. The RAM 73 temporarily stores various values ​​necessary for executing programs. The EEPROM 74 is a non-volatile memory device that stores various data.

[0070] I / O75 is connected to pedal 18, operation button 8, drive circuit 7A, and drive circuit 19A. CPU71 acquires the operating direction and amount of pedal 18. CPU71 drives the sewing machine motor 19 based on the acquired operating direction and amount. CPU71 acquires operation instructions from the operator via operation button 8.

[0071] The drive circuit 7A controls the operation of the display unit 7 based on control signals from the CPU 71. The display unit 7 displays an image based on the control of the drive circuit 7A. The display unit 7 accepts user touch input and outputs it to the CPU 71 via the drive circuit 7A.

[0072] The drive circuit 19A drives the sewing machine motor 19 in response to a torque command signal from the CPU 71. The sewing machine motor 19 is equipped with an encoder 19B. The encoder 19B detects the rotational angular phase and rotational speed of the sewing machine motor 19. The rotational angular phase is the upper axis angle. The encoder 19B outputs the detection result to the CPU 71 via I / O 75.

[0073] The user can fix the sensor unit 50 to the fixed plate 40 of the bed section 2. The user connects the connection terminal of the cable 63A extending from the first sensor 61 to the I / O 75 of the control unit 70. The user connects the connection terminal of the cable 65A extending from the second sensor 62 to the I / O 75 of the control unit 70. Therefore, the CPU 71 can obtain the detection result of the rotational position of the first detector 64 of the first sensor 61. The CPU 71 can obtain the detection result of the rotational position of the second detector 66 of the second sensor 62.

[0074] This section describes the user's needle gap adjustment process. In the process diagram shown in Figure 10, each step performed by the user is labeled U1, U2, etc.

[0075] Before the needle gap adjustment process, the user performs the preparation steps. The user removes the retaining foot 12 from the head 5. The user removes the sliding plate 16 from the opening 14.

[0076] The user removes the two countersunk screws 94, 94 that secure the needle plate 15. The user removes the needle plate 15 through the opening 14. The frame 26 is exposed through the opening 14. The user removes the feed dog 13 from the fixed surface 27 of the frame 26. The user removes the bobbin stopper. The user removes the bobbin case from the inner bobbin of the bobbin case 34. Thus the preparation process is completed. As shown in Figure 2, the bobbin mechanism 30 is exposed through the opening 14.

[0077] As shown in Figures 10 and 2, the user loosens the set screw 332 on the shaft portion 33 of the movable body 32 (U11). Thus, the movable body 32 becomes movable along the boiler shaft 28. Furthermore, the movable body 32 becomes rotatable independently of the boiler shaft 28.

[0078] Next, the user positions the sewing needle 11 at the meeting point height (U12). The user rotates the sewing machine pulley 6 to raise the needle bar 10 from its lowest position.

[0079] As shown in Figure 6, the needle bar 10 has four baselines 101 to 104 on its outer surface. Baselines 101 to 104 are horizontal lines extending horizontally. Baselines 101 to 104 are spaced apart in the vertical direction. Baselines 101 to 104 indicate the height of the needle bar 10 at its highest point or the height of the needle bar 10 when the sewing needle 11 is positioned at the meeting point, according to the specifications of the sewing machine 1. For example, if the sewing machine 1 is an X1 specification, baselines 101 and 102 are used. If the sewing machine 1 is an X2 specification, baselines 103 and 104 are used.

[0080] As shown in Figure 7, for example, in a sewing machine 1 of specification X1, the user rotates the sewing machine pulley 6 to raise the lower end of the needle bar 10 by a predetermined distance L1 from the lowest point P0. L1 is, for example, 1.8 mm. As shown in Figure 6, the user aligns the baseline 102 with the lower end of the needle bar metal 9. The sewing needle 11 is positioned at the height of the meeting point. As shown in Figure 7, the length L2 of the gap between the upper edge of the eyelet 110 and the needle tip 352 is, for example, 0.5 to 0.7 mm.

[0081] Next, as shown in Figure 7, the user rotates the movable body 32 so that the tip of the needle 352 aligns with the center of the sewing needle 11 (U13). The center of the sewing needle 11 is the center of the front-to-back width of the sewing needle 11 when the sewing machine 1 is viewed from the left.

[0082] Next, the user fixes the sensor unit 50 to the mounting plate 40 (U14). The user positions the first arm 522 and the second arm 523 of the arm section 52 along the upper surface of the mounting plate 40. The user aligns the through hole 525 of the fixing plate 524 of the first arm 522 with the screw hole 43 of the mounting plate 40. The user aligns the through hole 527 of the fixing plate 526 of the second arm 523 with the screw hole 44 of the mounting plate 40.

[0083] Next, the user uses the two countersunk screws 94, 94 that were used to fix the needle plate 15. The user fastens one countersunk screw 94 into the screw hole 43 through the through hole 525. The user fastens the other countersunk screw 94 into the screw hole 44 through the through hole 527. By fastening the countersunk screws 94, 94, the mounting position of the sensor unit 50 on the bed section 2 is precisely determined. Therefore, as shown in Figures 4 and 5, the sensor unit 50 is fixed to the plate to be fixed 40.

[0084] The lockstitch sewing machine has two screw holes 43 and 44 in the fixing plate 40 of the opening 14. Therefore, the sensor unit 50 can be fixed to any lockstitch sewing machine, even if it is a different model, as long as it has two screw holes 43 and 44.

[0085] As shown in Figure 5, when the sensor unit 50 is fixed to the bed section 2, the first contact surface 642 of the first sensor 61 contacts the sewing needle 11 from the left, opposite to the tip 352. The second contact surface 662 of the second sensor 62 contacts the tip of the bobbin case shaft 351 from the left.

[0086] The user performs the needle gap measurement operation using the operation button 8. As shown in Figure 11, the first screen 111 is displayed on the display unit 7. The upper part of the first screen 111 displays two messages in two lines: "Please bring the tip of the kettle into contact with the needle" and "The screen will automatically change when contact is detected." The lower part of the first screen 111 displays a start button. The user touches the start button (U15).

[0087] The user grasps the movable body 32 with their hand and moves it toward the sewing needle 11 (U16). The bobbin 34 approaches the sewing needle 11. The tip of the hook 352 of the bobbin 34 comes into contact with the sewing needle 11. The sewing needle 11 is pushed by the hook 352 and bends.

[0088] The user determines whether or not the second screen 112 is displayed on the display unit 7 (U17). Until the second screen 112 is displayed (U17: NO), the user returns to U16 and moves the movable body 32 toward the sewing needle 11.

[0089] When the sewing needle 11 bends to the left by a predetermined amount, the first sensor 61 detects the bending of the sewing needle 11. The predetermined amount is, for example, 0.01 mm. The screen of the display unit 7 switches automatically. The second screen 112 is displayed.

[0090] As shown in Figure 12, the upper part of the second screen 112 displays the measured value of the needle gap (mm). The lower part of the second screen 112 displays the previous screen button. Touching the previous screen button returns you to the first screen 111.

[0091] When the second screen 112 is displayed (U17:YES), the user checks the needle gap measurement displayed on the second screen 112. While checking the needle gap measurement, the user moves the bobbin 34 left and right along the axial direction (U18). The user determines whether the needle gap has reached the target value (U19). The target value should be adjusted according to the specifications of the sewing machine 1, for example, to 0-0.1 mm or 0-0.15 mm. Until the needle gap reaches the target value (U19:NO), the user returns to U18 and moves the bobbin 34 left and right.

[0092] Once the needle gap reaches the target value (U19: YES), the user tightens the two set screws 332 on the shaft portion 33 of the movable body 32 (U20). The movable body 32 is then fixed to the bobbin shaft 28. Thus, the needle gap adjustment process is completed.

[0093] Referring to Figure 13, the needle gap display process performed by the CPU 71 will be explained. In step U14 of the needle gap adjustment process shown in Figure 10, the sensor unit 50 is fixed to the fixed plate 40. The connection terminal of cable 63A of the first sensor 61 is connected to I / O 75 of the control unit 70. The connection terminal of cable 65A of the second sensor 62 is connected to I / O 75.

[0094] When the user performs a needle gap measurement operation using the operation button 8, the CPU 71 reads the needle gap display program from the ROM 72 and executes this process.

[0095] The CPU 71 displays the first screen 111 on the display unit 7 (S11). The CPU 71 determines whether or not the start button on the first screen 111 has been touched (S12). Until the start button is touched (S12: NO), the CPU 71 returns to S12 and waits.

[0096] When the start button is touched (S12:YES), the CPU 71 stores the current position of the first detector 64 of the first sensor 61 in the RAM 73 as the reference position (S13).

[0097] The CPU 71 starts measuring the output of the first sensor 61 (S14). The CPU 71 may update the output from the first sensor 61 at intervals of, for example, 5ms.

[0098] In U16 of Figure 10, the user moves the bobbin 34 toward the sewing needle 11. The CPU 71 calculates the displacement of the sewing needle 11 based on the stored reference position and the output value from the first sensor 61 (S15).

[0099] This embodiment assumes that the displacement of the sewing needle 11 is equal to the movement of the bobbin case 34. The CPU 71 determines whether the displacement is 0.01 mm or not (S16). The CPU 71 returns to S15 and repeats the process until the displacement is 0.01 mm (S16: NO).

[0100] When the displacement becomes 0.01 mm (S16: YES), the CPU 71 resets the output value from the second sensor 62 to 0.01 mm and determines the zero point position (S17). The zero point position is the rotational position of the second detector 66 of the second sensor 62 at the moment when the sewing needle 11 and the tip 352 of the bobbin come into contact. The CPU 71 stores the determined zero point position in the RAM 73 (S18).

[0101] The CPU 71 starts measuring the output of the second sensor 62 (S19). The output value from the second sensor 62 corresponds to the length of the needle gap. The CPU 71 displays the second screen 112 on the display unit 7 (S20) and displays the measured value of the needle gap.

[0102] The user checks the displayed needle gap measurement. The user adjusts the needle gap by moving the casing 34 (U18 in Figure 10). When the needle gap reaches the target value (U19: YES), the user tightens the two set screws 332 on the shaft portion 33 of the movable body 32 (U20). Once the needle gap adjustment process is complete, the user performs the termination operation using the operation button 8.

[0103] CPU 71 determines whether or not it has received a termination command (S21). Until it receives a termination command (S21: NO), CPU 71 returns to S20 and continues to display the second screen 112. Once it receives a termination command (S21: YES), CPU 71 terminates this process.

[0104] As described above, the sewing machine 1 of this embodiment comprises a needle bar 10, a bobbin mechanism 30, a bobbin shaft 28, a set screw 332, a bed section 2, a first sensor 61, a second sensor 62, an arm section 52, and a display section 7. The needle bar 10 is movable in the vertical direction, and a sewing needle 11 can be attached to its tip.

[0105] The bobbin mechanism 30 includes a movable body 32. The movable body 32 has a pointed tip 352. The pointed tip 352 catches the upper thread that is inserted into the sewing needle 11 attached to the needle bar 10. The bobbin shaft 28 extends in a left-right direction intersecting the up-down direction. The bobbin shaft 28 rotates the movable body 32 in a rotational direction around itself.

[0106] By loosening the set screw 332, the position of the movable body 32 in the axial direction of the boiler shaft 28 can be adjusted. By tightening the set screw 332, the movable body 32 is fixed to the boiler shaft 28. The bed section houses the boiler mechanism 30, the boiler shaft 28, and the set screw 332.

[0107] The first sensor 61 is located on one side in the axial direction relative to the sewing needle 11, which is positioned at the meeting point. The meeting point is the position of the sewing needle 11 at the moment when the needle tip 352 captures the upper thread loop. The first sensor 61 detects the amount of axial displacement of the sewing needle 11. The second sensor 62 detects the amount of axial displacement of the movable body 32.

[0108] The arm portion 52 supports the first sensor 61 and the second sensor 62 and is fixed to the bed portion 2.

[0109] The display unit 7 displays information based on the displacement of the movable body 32 detected by the second sensor 62, based on the displacement detected by the first sensor 61.

[0110] Therefore, the user can confirm the information based on the displacement of the movable body 32 displayed on the display unit 7. Therefore, the user can confirm the positional relationship between the tip 352 of the movable body 32 and the sewing needle 11. Therefore, the user can adjust the positional relationship between the tip 352 of the movable body 32 and the sewing needle 11 with high precision.

[0111] The sewing machine 1 includes a control unit 70. The first sensor 61 detects the amount of displacement of the sewing needle 11 when the tip 352 is in contact with the sewing needle 11. In the needle gap display process, the control unit 70 determines the reference position of the movable body 32 based on the detected amount of displacement of the sewing needle 11 (S13). The reference position of the movable body 32 is the reference position when the second sensor 62 detects the amount of displacement of the movable body 32.

[0112] Based on the reference position of the movable body 32 determined in S13, the control unit 70 displays information on the display unit 7 based on the amount of displacement of the movable body 32 detected by the second sensor 62.

[0113] Therefore, the user can easily confirm the positional relationship between the sewing needle 11, which is positioned at the meeting point, and the tip 352 of the movable body 32, based on the displayed information.

[0114] The information based on the displacement of the movable body 32 detected by the second sensor 62 is information about the length of the needle gap. The needle gap is the gap between the sewing needle 11 and the tip 352.

[0115] Therefore, the user can confirm the information on the needle gap length displayed on the display unit 7. Therefore, the user can easily confirm the positional relationship between the sewing needle 11 positioned at the meeting point and the tip 352 of the movable body 32.

[0116] The movable body 32 is equipped with a shaft 351. The shaft 351 is located on the same axis as the bobbin shaft 28 and protrudes in one direction in the axial direction. The first sensor 61 has a first contact surface 642 and detects the amount of axial displacement of the sewing needle 11. The first contact surface 642 is a surface that contacts the sewing needle 11, which is positioned at the meeting point, from one side in the axial direction. Therefore, the first sensor 61 can detect the amount of axial displacement of the sewing needle 11.

[0117] The second sensor 62 has a second contact surface 662 and detects the amount of axial displacement of the movable body 32. The second contact surface 662 is a surface that contacts the tip of the shaft 351 from one side in the axial direction. Therefore, the second sensor 62 can detect the amount of axial displacement of the movable body 32.

[0118] The first sensor 61 comprises a first detector 64 and a first detection unit 63. The first detector 64 is rotatable about a first rotation axis 641 that intersects the axial direction and has a first contact surface 642. The first detector 64 rotates about the first rotation axis 641 when the sewing needle 11 comes into contact with the first contact surface 642. The first detection unit 63 detects the rotational position of the first detector 64.

[0119] The second sensor 62 comprises a second detector 66 and a second detection unit 65. The second detector 66 is rotatable about a second rotation axis 661 that intersects the axial direction and has a second contact surface 662. The second detector 66 rotates about the second rotation axis 661 when the tip of the shaft 351 contacts the second contact surface 662. The second detection unit 65 detects the rotational position of the second detector 66.

[0120] The first sensor 61 converts the displacement of the sewing needle 11 into the rotation of the first detector 64, and the first detection unit 63 detects the rotational position of the first detector 64. Therefore, compared to a configuration that directly detects the displacement of the sewing needle 11, the first sensor 61 can accurately detect the displacement of the sewing needle 11 regardless of its size or shape.

[0121] The second sensor 62 converts the displacement of the axis 351 of the movable body 32 into the rotation of the detector, and the second detection unit 65 detects the rotational position of the second detector 66. Therefore, compared to a configuration that directly detects the displacement of the movable body 32, the second sensor 62 can accurately detect the displacement of the movable body 32 regardless of the size or shape of the sewing needle 11.

[0122] The tip 352 can contact the sewing needle 11 from the other side in the axial direction. The tip 352 contacts the sewing needle 11 from the other side. The sewing needle 11 bends to one side. Therefore, the first sensor 61 can detect the amount of bending of the sewing needle 11 as a displacement.

[0123] In the above description, the control unit 70 is an example of the "control unit" of the present invention. The display unit 7 is an example of the "notification unit" of the present invention. The set screw 332 is an example of the "position adjustment mechanism" of the present invention. The CPU 71 that executes S17 of the needle gap display process in Figure 13 is an example of the "determination process" of the present invention. The CPU 71 that executes S20 is an example of the "output process" of the present invention.

[0124] U12 in Figure 10 is an example of the "first step" of the present invention. U14 is an example of the "second step" of the present invention. U16 is an example of the "third step" of the present invention.

[0125] The CPU 71 executing S15 in Figure 13 is an example of the "fourth step" of the present invention. The CPU 71 executing S17 is an example of the "fifth step" of the present invention. The CPU 71 executing S20 is an example of the "sixth step" of the present invention.

[0126] The above embodiments can be modified in various ways.

[0127] The first modified example will now be described. The sewing machine 1 displays the needle gap measurement value from the sensor unit 50 on the display unit 7 of the sewing machine 1. The sewing machine 1 may also display the needle gap measurement value from the sensor unit 50 on a display terminal such as a tablet.

[0128] The display terminal 170 shown in Figure 15 is equipped with a display unit 77. The display terminal 170 is connected to the I / O 75 of the control unit 70 via a cable. The sewing machine 1 may display the needle gap measurement value from the sensor unit 50 on the display unit 77 of the display terminal 170.

[0129] A second modified example will now be described. In the above embodiment, the CPU 71 of the control unit 70 of the sewing machine 1 performs the needle gap display processing. For example, the control unit 80 of the display terminal 170 connected to the sewing machine 1 may perform the needle gap display processing.

[0130] As shown in Figure 15, the display terminal 170 includes a control unit 80. The control unit 80 includes a CPU 81, ROM 82, RAM 83, and I / O 85. The CPU 81 controls the operation of the display terminal 170. The CPU 81 is connected to the ROM 82, RAM 83, and I / O 85 via a bus. The ROM 82 stores various programs, etc. The RAM 83 temporarily stores various values ​​necessary for executing programs.

[0131] I / O85 is connected to the display unit 77. The user connects the connector of cable 63A extending from the first sensor 61 to I / O85. The user connects the connector of cable 65A extending from the second sensor 62 to I / O85.

[0132] Therefore, the CPU 81 can obtain the detection result of the rotational position of the first detector 64 of the first sensor 61. The CPU 81 can obtain the detection result of the rotational position of the second detector 66 of the second sensor 62. Therefore, the control unit 80 of the display terminal 170 can execute the needle gap display process shown in Figure 13. The control unit 80 is an example of the control unit of the present invention.

[0133] A third modification will be described. The first sensor 61 and the second sensor 62 of the sensor unit 50 are contact-type displacement sensors. Instead of contact-type displacement sensors, the sensor unit may be equipped with non-contact-type displacement sensors.

[0134] The sensor unit 500 shown in Figure 16 comprises an arm portion 52, a first sensor 610, and a second sensor 620. The arm portion 52 has the same configuration as the arm portion 52 of the sensor unit 50. Therefore, the user can fix the sensor unit 500 to the fixed plate 40 of the bed portion 2.

[0135] The first sensor 610 and the second sensor 620 are non-contact laser sensors.

[0136] The substrate 51 has a screw hole 511 in its upper region. The screw hole 511 penetrates the substrate 51 in the left-right direction. A female thread is arranged on the inner surface of the screw hole 511. The substrate 51 has a screw hole 512 in its lower region. The screw hole 512 penetrates the substrate 51 in the left-right direction. A female thread is arranged on the inner surface of the screw hole 512.

[0137] The first sensor 610 is a round bar extending in the left-right direction. The first sensor 610 has a male thread on its outer surface. The second sensor 620 is a round bar extending in the left-right direction. The second sensor 620 has a male thread on its outer surface.

[0138] The first sensor 610 is screwed into the screw hole 511 from left to right. The male threads on the outer surface of the first sensor 610 engage with the female threads in the screw hole 511. The first sensor 610 protrudes to the right from the screw hole 511. By rotating the first sensor 610, the user can adjust the amount of protrusion from the screw hole 511. A nut 97 is fastened to the first sensor 610. The nut 97 abuts against the left side of the circuit board 51. The nut 97 fixes the position of the first sensor 610.

[0139] The second sensor 620 is screwed into the screw hole 512 from left to right. The male threads on the outer surface of the second sensor 620 engage with the female threads in the screw hole 512. The second sensor 620 protrudes to the right from the screw hole 512. By rotating the second sensor 620, the user can adjust the amount of protrusion from the screw hole 512. A nut 98 is fastened to the second sensor 620. The nut 98 abuts against the left side of the circuit board 51. The nut 98 fixes the position of the second sensor 620.

[0140] The laser beam emitted from the tip of the first sensor 610 strikes the sewing needle 11. The light is reflected by the surface of the sewing needle 11. The reflected laser beam returns to the light receiving unit of the first sensor 610. The light receiving unit detects the intensity of the reflected light and the position where it was received. The control unit 70 calculates the distance to the sewing needle 11 based on the time it takes for the light received by the light receiving unit to return. Based on the calculated distance information, the control unit 70 can determine the position of the sewing needle 11.

[0141] The laser beam emitted from the tip of the second sensor 620 strikes the tip of the shaft 351 of the inner casing. The light is reflected by the surface of the tip of the shaft 351. The reflected laser beam returns to the light-receiving section of the second sensor 620. The light-receiving section detects the intensity of the reflected light and the position where it was received. The control unit 70 calculates the distance to the tip of the shaft 351 based on the time it takes for the light received by the light-receiving section to return. Based on the calculated distance information, the control unit 70 can determine the position of the tip of the shaft 351.

[0142] This embodiment can be modified in various ways in addition to the above modifications. The bobbin 34 is a full-rotation vertical bobbin, but it may also be a half-rotation vertical bobbin. Furthermore, although the sewing machine in this embodiment is assumed to be an industrial lockstitch sewing machine, it may also be other industrial sewing machines or household sewing machines.

[0143] In the boiler mechanism 30, the axial position of the movable body 32 can be adjusted by tightening or loosening the set screw 332 on the shaft portion 33. The position adjustment mechanism for the movable body 32 may be a different mechanism from the set screw 332. For example, a rotating body may be provided at the position of the set screw, and a mechanical mechanism may be provided to directly move the position of the movable body 32 according to the amount of rotation for adjustment.

[0144] In the above embodiment, the measured value of the needle gap is displayed on the display unit 7. Information other than the measured value may also be displayed as information related to the needle gap. For example, the sewing machine may display a message on the display unit 7 indicating whether the needle gap is appropriate or not. Alternatively, the sewing machine may display the result of determining whether the needle gap is appropriate or not using color on the display unit 7.

[0145] In addition to the display unit 7, the sewing machine may also notify the user of the result of whether the needle gap is correct using a light-emitting part such as an LED. The sewing machine may also notify the user of whether the needle gap is correct by sound from a speaker. The sewing machine may also notify the user of whether the needle gap is correct by voice from a speaker. [Explanation of Symbols]

[0146] 1 Sewing machine 2 Bed section 7 Display section 10 needle bars 11 Sewing needle 15 Needle Plate 28 Pot shaft 30. Kettle mechanism 32 Movable body 34 Kettle 43, 44 screw holes 50 Sensor Units 52 Arm section 61 First Sensor 62. Second Sensor 63 First detection unit 64 First detector 65 Second detection unit 66 Second detector 70 Control Unit 77 Display section 80 Control Unit 94 Countersunk screws 170 Display terminals 331 screw holes 332 Set screw 351 axis 352 Sword tip 525,527 Through holes 641 First rotation axis 642 1st contact surface 661 Second rotation axis 662 Second contact surface

Claims

1. A needle bar that is movable in the vertical direction and to which a sewing needle can be attached at the tip, A bobbin mechanism comprising a movable body having a pointed tip for capturing the upper thread that is inserted into the sewing needle attached to the needle bar, A boiler shaft having an axis extending in a direction intersecting the aforementioned vertical direction, which rotates the movable body in a rotational direction around the axis, A position adjustment mechanism that can adjust the position of the movable body in the axial direction of the boiler shaft, A bed section housing the boiler mechanism, the boiler shaft, and the position adjustment mechanism, A first sensor is positioned on one side in the axial direction of the sewing needle, which is the meeting position of the sewing needle at the timing when the tip of the needle catches the loop formed in the upper thread, and detects the amount of axial displacement of the sewing needle. A second sensor for detecting the amount of axial displacement of the movable body, An arm portion that supports the first sensor and the second sensor and is fixed to the bed portion, A notification unit that notifies information based on the displacement amount of the movable body detected by the second sensor, based on the displacement amount detected by the first sensor. A sewing machine characterized by having the following features.

2. Equipped with a control unit, The control unit, A determination process to determine the reference position of the movable body when the second sensor detects the displacement of the movable body, based on the amount of displacement of the sewing needle detected by the first sensor when the tip of the needle is in contact with the sewing needle, Based on the reference position determined in the determination process, an output process is performed to output information based on the amount of displacement of the movable body detected by the second sensor to the notification unit. A sewing machine according to claim 1, characterized in that it performs the following:

3. The aforementioned information refers to the length of the needle gap, which is the gap between the sewing needle and the tip of the needle. The output process is a process that outputs the information to the display unit. The sewing machine according to claim 2, characterized by the following:

4. The movable body is located on the same axis as the boiler shaft and has a shaft that protrudes in one direction in the axial direction, The first sensor has a first contact surface that contacts the sewing needle positioned at the meeting position from one side in the axial direction, and detects the amount of axial displacement of the sewing needle. The sewing machine according to claim 1, wherein the second sensor has a second contact surface that contacts the tip of the shaft from one side in the axial direction, and detects the amount of axial displacement of the movable body.

5. The first recall was, A first detector having the first contact surface is rotatable about a first rotation axis intersecting the axial direction, A first detection unit detects the rotational position of the first detector, which rotates around a first rotation axis when the sewing needle comes into contact with the first contact surface. Equipped with, The second recovery is, The second detector is rotatable about a second rotation axis intersecting the axial direction and has the second contact surface, A second detection unit detects the rotational position of the second detector, which rotates around the second rotation axis, by the tip of the shaft contacting the second contact surface. Having A sewing machine according to claim 4, characterized by the following:

6. The tip of the blade is capable of contacting the sewing needle from the other side in the axial direction. A sewing machine according to claim 1, characterized by the following:

7. A method for adjusting the position of the movable body relative to the sewing needle in the sewing machine according to any one of claims 1 to 6, The first step is to position the sewing needle at the meeting point, A second step involves fixing the sensor unit having the first sensor, the second sensor, and the arm portion to the bed portion. After the first step positions the sewing needle at the meeting position and the second step fixes the sensor unit to the bed, the third step involves moving the movable body toward the sewing needle from the other side in the axial direction, In the third step, the tip of the movable body, which has moved, comes into contact with the sewing needle, causing the sewing needle to bend. In the fourth step, the first sensor detects the amount of displacement of the sewing needle. A fifth step in which, based on the amount of displacement of the sewing needle detected in the fourth step, the reference position of the movable body when the second sensor detects the amount of displacement of the movable body is determined, A sixth step in which, based on the reference position determined in the fifth step, the information based on the amount of displacement of the movable body detected by the second sensor is output to the notification unit. An adjustment method characterized by comprising the following features.

8. A sensor unit used in the sewing machine according to any one of claims 1 to 6, The first sensor and, The above-mentioned second sensor, The aforementioned arm portion and A sensor unit characterized by having the following features.

9. The arm portion has through holes in positions corresponding to screw holes provided in the bed portion for fixing the needle plate. The sensor unit according to claim 8, characterized by the following:

10. A sensor unit for use in a sewing machine comprising: a needle bar that is movable in the vertical direction and to which a sewing needle can be attached at its tip; a bobbin mechanism having a movable body with a pointed tip for capturing the upper thread inserted into the sewing needle attached to the needle bar; a bobbin shaft having an axis extending in a direction intersecting the vertical direction and rotating the movable body in a rotational direction about the axis; a position adjustment mechanism that can adjust the position of the movable body in the axial direction of the bobbin shaft; and a bed section housing the bobbin mechanism, the bobbin shaft, and the position adjustment mechanism, A first sensor is positioned on one side in the axial direction of the sewing needle, which is the meeting position of the sewing needle at the timing when the tip of the needle catches the loop formed in the upper thread, and detects the amount of axial displacement of the sewing needle. A second sensor for detecting the amount of axial displacement of the movable body, A notification unit that notifies information based on the displacement amount of the movable body detected by the second sensor, based on the displacement amount detected by the first sensor, An arm portion that supports the first sensor and the second sensor and is fixed to the bed portion, A control unit that performs a determination process to determine the reference position of the movable body when the second sensor detects the displacement of the movable body based on the amount of displacement of the sewing needle detected by the first sensor when the tip of the needle is in contact with the sewing needle, and an output process to output information based on the amount of displacement of the movable body detected by the second sensor to the notification unit based on the reference position determined in the determination process. A sensor unit characterized by having the following features.

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