Sewing device

Abstract

The invention provides a sewing device which is helpful for reducing bad conditions caused by sewing when foreign matters and the like are clamped between a presser foot and a needle plate. The sewing device comprises a needle bar; a needle bar mechanism; a spindle motor; a needle plate; the pressing rod is used for mounting the pressing foot and pressing the sewed object carried on the needle plate by using the pressing foot; the pressing mechanism enables the pressing rod to move up and down between an ascending position and a descending position; a pressing motor that drives the pressing mechanism; a detector that detects a detection position of the pressure lever; a calculation unit that calculates an estimated position of the pressure lever in the vertical direction; a threshold value acquisition unit that acquires a threshold value; and a pressure lever control unit for controlling the driving of the pressure motor, raising the pressure lever when the absolute value of the difference between the detection position and the estimated position is equal to or greater than a threshold value during a given period in which the pressure lever is lowered from the raised position, and lowering the pressure lever when the absolute value of the difference between the detection position and the estimated position is less than the threshold value.

Description

Technical Field

[0001] The present invention relates to a sewing device. Background Art

[0002] The sewing device disclosed in Patent Document 1 includes a prohibition mechanism that prohibits the operation of the sewing machine motor and the upper thread drawing device when the cloth thickness detecting mechanism fails to detect cloth thickness information.

[0003] Patent Document 1: Japanese Patent Application Laid-Open No. 63-275397 Summary of the Invention

[0004] In conventional sewing devices, the sewing machine motor and the upper thread drawing device are operated in a state where a foreign object or the like is caught between the presser foot and the needle plate.

[0005] An object of the present invention is to provide a sewing device that helps reduce inconvenience caused by sewing in a state where foreign matter or the like is caught between a presser foot and a needle plate.

[0006] The sewing device involved in the technical solution 1 of the present invention comprises: a needle bar extending in the up-down direction and capable of mounting a machine needle at the lower end; a needle bar mechanism that causes the needle bar to move up and down; a spindle motor that drives the needle bar mechanism; a needle plate formed with a needle hole through which the machine needle can be inserted; a pressure bar, at the lower end of which a presser foot can be mounted, for pressing a sewn object placed on the needle plate from above by means of the presser foot; a pressing mechanism that causes the pressure bar to move up and down between an ascending position and a descending position, the ascending position being a position in which the presser foot is above the needle plate and away from the needle plate, and the descending position being a position lower than the case in which the presser foot is in the ascending position and closer to the needle plate. A pressing motor drives the pressing mechanism; a detector detects a detected position, which is the position of the press bar in the vertical direction; a calculation unit calculates an estimated position of the press bar in the vertical direction estimated based on the amount of drive of the pressing motor; a threshold value acquisition unit acquires a threshold value; and a press bar control unit controls the drive of the pressing motor so that, during a predetermined period of time when the press bar is lowered from the raised position, the press bar is raised if a first value of a difference between the detected position and the estimated position is greater than a threshold value, and is lowered if a second value of the difference between the detected position and the estimated position is less than the threshold value. The sewing device sets the threshold value so that the absolute value of the difference between the detected position and the estimated position is greater than the threshold value when a foreign object or the like is caught between the presser foot and the needle plate. This helps prevent sewing from being performed with the foreign object or the like caught between the presser foot and the needle plate.

[0007] In the sewing device according to claim 2 of the present invention, the predetermined period is a period during which the pressure bar is located within a comparison range, wherein the comparison range is set as a portion of the movable range from the raised position to the lowered position. Compared to a case where the absolute value of the difference between the detected position and the estimated position is greater than or equal to a threshold value within the entire movable range of the pressure bar, the pressure bar control unit of the sewing device facilitates simpler processing performed by the pressure bar control unit.

[0008] The comparison range of the sewing device according to claim 3 of the present invention is a range in which the distance in the vertical direction from the needle plate is greater than the thickness of the workpiece. The presser bar control unit of the sewing device helps to avoid a situation in which the presser bar is raised when the absolute value of the difference between the detected position and the estimated position is greater than a threshold value, when no foreign matter is caught between the presser foot and the needle plate and the presser foot is in contact with the workpiece.

[0009] The press bar control unit of the sewing device according to the fourth technical solution of the present invention lowers the press bar at a first speed when the estimated position is within the comparison range and in the second situation when the press bar is lowered from the raised position. When the estimated position is outside the comparison range when the press bar is lowered from the raised position, the press bar control unit lowers the press bar at a second speed that is faster than the first speed. The press bar control unit of the sewing device lowers the press bar more slowly within the comparison range, where there is a possibility of foreign matter being caught between the presser foot and the needle plate, than outside the comparison range, thereby helping to suppress the impact of the presser foot colliding with foreign matter. Compared to a case where the press bar is lowered at the first speed outside the comparison range in addition to within the comparison range, the press bar control unit of the sewing device helps to shorten the time required for the press bar to complete its descent.

[0010] The sewing device according to claim 5 of the present invention further includes a comparison range updating unit configured to update the comparison range based on the detected position in the first case. The comparison range updating unit of the sewing device updates the comparison range based on the detected position when the absolute value of the difference between the actual detected position and the estimated position is greater than or equal to a threshold value and when a foreign object or the like is caught between the presser foot and the needle plate, thereby facilitating more accurate detection of a foreign object or the like caught between the presser foot and the needle plate.

[0011] The sewing device according to claim 6 of the present invention further comprises: a storage control unit for storing, in a storage unit, a fact that the presser bar was raised in the first case as an error; and a warning notification unit for notifying, when the error is stored in the storage unit, a warning before lowering the presser bar from the raised position. The storage control unit and the warning notification unit of the sewing device draw attention to the recurrence of the error through the warning, thereby helping to prevent the presser bar from being lowered from the raised position when a foreign object, etc., is caught between the presser foot and the needle plate.

[0012] The sewing device according to claim 7 further includes a storage unit that pre-stores the comparison range and the threshold value set for each type of the sewn workpiece, and the presser bar control unit raises the presser bar in the first case and lowers the presser bar in the second case within the given period, depending on the type of the sewn workpiece and based on the comparison range and the threshold value stored in the storage unit. Compared to a case where the presser bar control unit performs processing using the same comparison range and threshold value regardless of the type of the sewn workpiece, the storage unit and the presser bar control unit of the sewing device facilitate appropriate processing by the presser bar control unit.

[0013] The sewing device according to claim 8 further includes an error notification unit configured to notify an operator of an error when the pressure bar is raised in the first case. The error notification unit of the sewing device notifies the operator of the error, thereby facilitating appropriate error handling. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a perspective view of the sewing device 1.

[0015] Figure 2 It is a perspective view of a part of the internal structure of the sewing device 1.

[0016] Figure 3 It is a front view of a part of the internal structure of the sewing device 1.

[0017] Figure 4 (a) is a left side view of a part of the internal structure of the sewing device 1 when the pressing mechanism 44 is located at the needle lower position. Figure 4 (b) is a left side view of a part of the internal structure of the sewing device 1 when the pressing mechanism 44 is located at the needle upper position.

[0018] Figure 5 (a) is an explanatory diagram of the middle pressure rod 8 and the outer pressure rod 10 in the lowered position. Figure 5 (b) is an explanatory diagram of the middle pressure rod 8 and the outer pressure rod 10 in the raised position. Figure 5(c) is an explanatory diagram of the intermediate pressure rod 8 and the outer pressure rod 10 at the completion of descent.

[0019] Figure 6 It is a block diagram of the electrical structure of the sewing device 1.

[0020] Figure 7 It is a flowchart of the pressure rod lowering process. DETAILED DESCRIPTION

[0021] The physical structure of the sewing device 1 of the present invention is described. In the following description, left and right, front and back, and up and down are indicated by arrows in the figure. Figure 1 、 Figure 2 As shown, the sewing device 1 is a compound feed sewing machine including a base 2 , a support 3 , an arm 4 , and a head 5 .

[0022] like Figure 1 、 Figure 2 as well as Figure 5 As shown in (a) of FIG, the base 2 has a needle plate 14 on its upper surface, which houses the shuttle mechanism, feed mechanism 36, and feed amount adjustment mechanism 37. The shuttle mechanism is driven by the rotation of the lower shaft 40, winding the upper and lower threads beneath the needle plate 14. The needle plate 14 is formed with a needle hole 20 through which the needle 7 can be inserted. The lower shaft 40 rotates synchronously with the main shaft 31 via a belt 35 that is stretched between the main shaft 31 and the lower shaft 40.

[0023] The feeding mechanism 36 includes an upper and lower feeding shaft 38, an eccentric link 69 (see Figure 4 ), an eccentric rod (not shown), a converter 66, a horizontal feed shaft 39, a connecting rod mechanism 53 and a feed tooth 17, which drives the feed tooth 17 in synchronization with the rotation of the lower shaft 40, so that the sewn material moves in the conveying direction at a given feed amount. The conveying direction is rearward or forward. The lower shaft 40, the upper and lower feed shafts 38 and the horizontal feed shaft 39 extend in the left-right direction. The upper and lower feed shafts 38 are located in front of the horizontal feed shaft 39. The upper and lower feed shafts 38 are connected to the lower shaft 40 via an eccentric connecting rod 69 that is eccentric with respect to the axis of the lower shaft 40. The eccentric rod is eccentrically arranged on the lower shaft 40 to the right of the eccentric connecting rod 69. The converter 66 is connected to the rear end portion of the eccentric rod eccentrically arranged on the lower shaft 40, and transmits the rotation of the lower shaft 40 caused by the rotation of the main shaft 31 to the horizontal feed shaft 39. The left ends of the vertical feed shaft 38 and the left end of the horizontal feed shaft 39 are connected to the feed tooth 17 via a link mechanism 53 .

[0024] The feed amount adjustment mechanism 37 includes the feed amount adjustment motor 24, an intermediate shaft 28, a converter 66, a cam rod 67, a cam plate 65, and a horizontal feed shaft 39. The intermediate shaft 28 extends horizontally and is connected to the horizontal feed shaft 39 via the converter 66. A cam rod 67 is provided at the right end of the intermediate shaft 28, which contacts a cam plate 65 provided on the output shaft of the feed amount adjustment motor 24. The feed amount adjustment motor 24 is a pulse motor. By rotating the output shaft, the feed amount adjustment motor 24 changes the rotation amount of the horizontal feed shaft 39 via the cam plate 65, cam rod 67, intermediate shaft 28, and converter 66, thereby adjusting the feed amount in the front-to-back direction of the sewn material by the feed mechanism 36. When the lower shaft 40 rotates synchronously with the main shaft 31, the upper and lower feed shafts 38 and the horizontal feed shaft 39 oscillate, causing the feed tooth 17 to rotate counterclockwise or clockwise when viewed from the left, describing an elliptical trajectory.

[0025] The support column 3 extends upward from the right end of the base 2 and houses the spindle motor 21, the pressure motor 22, the belt 35, and the drive link 41. The spindle motor 21 rotates the spindle 31. The pressure motor 22 is a pulse motor located to the left and rear of the spindle motor 21. It adjusts the downward pressure applied to the sewing material by the outer presser foot 11 mounted at the lower end of the outer presser bar 10. The drive link 41 is connected to the horizontal feed shaft 39 and the needle bar swing shaft 42.

[0026] The arm 4 extends to the left from the upper end of the support 3. The arm 4 has a display unit 15, input units 16, 19, and a clamp 13 on its front surface. The display unit 15 is a liquid crystal display that displays images, and the input unit 16 is a touch panel provided on the front surface of the display unit 15, which can input various instructions to the control unit 90. The input unit 19 is provided to the right of the display unit 15 and is a switch for inputting various instructions to the control unit 90. The clamp 13 has Figure 6 The thread tensioning solenoid 25 shown is used to apply a given tension to the thread by driving the thread tensioning solenoid 25 .

[0027] The arm 4 accommodates the thread clamping solenoid 25, the alternating lift adjustment motor 23, the main shaft 31, the pressing shaft 26, the needle bar swing shaft 42, the intermediate shaft 27, the swing shaft 45, and the alternating lift adjustment mechanism 50. The thread clamping solenoid 25 is a proportional solenoid, and the sewing device 1 can adjust the tension applied to the face thread by adjusting the driving voltage supplied to the thread clamping solenoid 25. The alternating lift adjustment motor 23 is a pulse motor located to the left of the main shaft motor 21 and the pressing motor 22. The main shaft 31, the pressing shaft 26, the needle bar swing shaft 42, the intermediate shaft 27, and the swing shaft 45 extend in the left-right direction. The right end of the main shaft 31 is connected to the main shaft motor 21, and the left end is connected to the needle bar mechanism 32. The pressing shaft 26 is located behind the main shaft 31 and has a fan gear 64 at its right end. The sector gear 64 meshes with the pinion 61 provided on the output shaft of the pressing motor 22 and rotates when the pressing motor 22 is driven. Therefore, the pressing shaft 26 rotates when the pressing motor 22 is driven. The left end of the pressing shaft 26 is connected to the pressing mechanism 44. Therefore, the pressing motor 22 drives the pressing mechanism 44.

[0028] The right end of the needle bar swing shaft 42 is connected to the drive link 41, and the left end is connected to the swing mechanism 34. The alternating lift amount adjustment mechanism 50 includes an alternating lift amount adjustment motor 23, a cam mechanism 62, an intermediate shaft 27, a converter 63, and a swing shaft 45. The output shaft of the alternating lift amount adjustment motor 23 is connected to the intermediate shaft 27 via the cam mechanism 62. The intermediate shaft 27 is connected to the swing shaft 45 via the converter 63. The alternating lift amount adjustment motor 23 adjusts the alternating lift amount by rotating the output shaft, thereby changing the swing amount of the swing shaft 45 via the cam mechanism 62, the intermediate shaft 27, and the converter 63. The alternating lift amount is the lift amount relative to the needle plate 14 when the middle pressure rod 8 and the outer pressure rod 10 alternately move up and down in synchronization with the rotation of the main shaft 31.

[0029] The head 5 is mounted on the left end of the arm 4, with a thread take-up lever 12 mounted on its front surface. The thread take-up lever 12 lifts the upper thread to create a knot with the lower thread. The head 5 houses the needle bar mechanism 32, the thread take-up lever mechanism 33, the pressing mechanism 44, the swing mechanism 34, and the detector 49. The needle bar mechanism 32 is connected to the main shaft 31, causing the needle bar 6 to move up and down. The thread take-up lever mechanism 33 rotates in sync with the main shaft 31, causing the thread take-up lever 12 to move up and down.

[0030] The pressing mechanism 44 has a pressing motor 22, and utilizes the power of the pressing motor 22 to press the Figure 5 The middle presser foot 9 and the outer presser foot 11 shown in (b) are above the needle plate 14 and away from the rising position of the needle plate 14. Figure 5As shown in (a), the middle presser foot 9 and the outer presser foot 11 are moved up and down between a position lower than when the middle presser foot 9 and the outer presser foot 11 are in the raised position and closer to the lowered position of the needle plate 14. The pressing mechanism 44 is connected to the left end of the pressing shaft 26 and comprises an outer pressure rod 10, an middle pressure rod 8, a swing shaft 45, connecting rods 46, 47, 70, a triangular lever 48, a force member 51, an adjustment member 52, a converter 63, and an eccentric rod 68. The middle pressure rod 8 can be equipped with the middle presser foot 9 at its lower end, and the middle presser foot 9 can be used to press the sewn material placed on the needle plate 14 from above. The outer pressure rod 10 can be equipped with the outer presser foot 11 at its lower end, and the outer presser foot 11 can be used to press the sewn material placed on the needle plate 14 from above. The left end of the swing shaft 45 is connected to a connecting rod 46 extending in the up-down direction. The lower end of the connecting rod 46 is connected to the rear end of a connecting rod 47 extending in the front-back direction. The triangular lever 48 is triangular in shape when viewed from the left, with one of its three corners connected to the front end of the connecting rod 47. The remaining two of the three corners of the triangular lever 48 are connected to the outer pressure rod 10 and the connecting rod 70. One end of the connecting rod 70 is connected to the triangular lever 48, and the other end is connected to the intermediate pressure rod 8.

[0031] The biasing member 51 is a coiled compression spring inserted into the external pressure rod 10, pressing the external pressure rod 10 downward. The adjustment member 52 is a cylindrical member with the biasing member 51 inserted inside, allowing for vertical movement. The adjustment member 52 is driven by the pressing motor 22 to move up and down, adjusting the downward pressure exerted by the biasing member 51 on the external pressure rod 10.

[0032] The converter 63 is connected to the rear end of an eccentric rod 68 eccentrically disposed on the main shaft 31, and transmits the rotation of the main shaft 31 caused by the drive of the main shaft motor 21 to the swing shaft 45, causing the swing shaft 45 to swing. When the swing shaft 45 swings due to the rotation of the main shaft 31, the connecting rod 46 swings around the swing shaft 45. As the connecting rod 46 swings, the connecting rod 47 moves in the front-back direction, causing the outer pressure rod 10 and the middle pressure rod 8 to move in the up-down direction via the triangular lever 48. Figure 4 As shown in (a), when the connecting rod 47 moves forward, the outer pressure rod 10 rises and the middle pressure rod 8 falls. Figure 4 As shown in (b), when the connecting rod 47 moves backward, the outer pressure rod 10 descends and the intermediate pressure rod 8 rises. The pressing mechanism 44 synchronizes with the rotation of the main shaft 31 to move the outer pressure rod 10 and the intermediate pressure rod 8 in opposite phases, that is, alternately move up and down, and use the outer presser foot 11 and the intermediate presser foot 9 to press the sewn material from above toward the needle plate 14 alternately.

[0033] The swing mechanism 34 is connected to the needle bar swing shaft 42, and synchronously with the rotation of the main shaft 31, the needle bar 6 and the middle pressure rod 8 are swung in the conveying direction of the sewn material by an amount corresponding to the swing amount of the needle bar swing shaft 42. Figure 4As shown in (a), the state in which the lower end of the needle 7 is located below the needle plate 14, the outer presser foot 11 is located upward and away from the needle plate 14, and the intermediate presser foot 9 is located near the feed tooth 17 is referred to as the state in which the pressing mechanism 44 is located in the needle down position. While the pressing mechanism 44 is in the needle down position, the sewing device 1 causes the needle bar 6, the intermediate presser bar 8, and the feed tooth 17 to swing backward while the needle 7 is inserted into the sewing material. Figure 4 As shown in (b), the state in which the lower end of the needle 7 is located above the needle plate 14, the outer presser foot 11 is located close to the needle plate 14, and the intermediate presser foot 9 is located upward and away from the needle plate 14 is referred to as the state in which the pressing mechanism 44 is located in the needle-up position. While the pressing mechanism 44 is located in the needle-up position, the sewing device 1 swings the needle bar 6, the intermediate presser bar 8, and the feed tooth 17 forward without the needle 7 piercing the workpiece.

[0034] The detector 49 detects the vertical position of the middle pressure rod 8 and the outer pressure rod 10, that is, the detection position. The detector 49 is, for example, a magnetic sensor provided on the head 5, which detects the vertical position of the magnetic body 71 provided on the pressure rod clamp 60, which supports the outer pressure rod 10 so as to be able to move up and down. The sewing device 1 is provided with a needle bar 6, an outer pressure rod 10 and a middle pressure rod 8 at the lower part of the head 5, which are driven by the main shaft motor 21 to move up and down. The needle bar 6 extends up and down in front of the middle pressure rod 8, and the needle 7 can be loaded and unloaded at its lower end. The thread spool supplies the upper thread to the needle eye of the needle 7.

[0035] Reference Figure 6 The electrical structure of the sewing device 1 will be described. The control unit 90 of the sewing device 1 includes a CPU 91, a ROM 92, a RAM 93, a storage device 94, an input / output interface (I / O) 95, and drive circuits 81 to 86. The CPU 91 comprehensively controls the operation of the sewing device 1. The ROM 92 pre-stores programs for executing various processes. The RAM 93 temporarily stores various information generated during the execution of various processes.

[0036] The storage device 94 is non-volatile and stores various set values. The storage device 94 includes a sewing condition storage area 97 and an error storage area 98. The storage device 94 of this embodiment stores sewing conditions including comparison ranges and thresholds for each type of sewn material in the sewing condition storage area 97. The comparison range is set from Figure 5 (b) shows the rising position to Figure 5 The middle pressure rod 8 and the outer pressure rod 10 are positioned in the lowered position shown in (a). Figure 5 (a) shows a part of the movable range RA. Figure 5 In (a), the movable range RA of the middle pressure rod 8 and the outer pressure rod 10 is represented by the movable range of the lower end of the outer pressure foot 11 installed at the lower end of the outer pressure rod 10. Figure 5 As shown in (b), the comparison range R1 is a range in which the vertical distance D from the needle plate 14 to the comparison range R1 is greater than the thickness J of the workpiece. In other words, the comparison range R1 is set above the workpiece placed on the needle plate 14. Figure 5 In (b), the comparison range R1 is represented by the range of the position of the lower end of the outer presser foot 11 attached to the lower end of the outer presser bar 10. If an error occurs during the presser bar lowering process described later, the error storage area 98 stores information such as the operator ID in association with the date and time of the error occurrence. Storage areas 97 and 98 may also store information in peripheral devices connected to the sewing device 1, other sewing devices 1, and the cloud.

[0037] Each of the drive circuits 81 to 86 is connected to the I / O 95. The drive circuit 81 is connected to the spindle motor 21 and drives the spindle motor 21 according to the control instructions of the CPU 91. The drive circuit 82 is connected to the feed amount adjustment motor 24 and drives the feed amount adjustment motor 24 according to the control instructions of the CPU 91. The drive circuit 83 is connected to the alternating lift amount adjustment motor 23 and drives the alternating lift amount adjustment motor 23 according to the control instructions of the CPU 91. The drive circuit 84 is connected to the pressing motor 22 and drives the pressing motor 22 according to the control instructions of the CPU 91. The drive circuit 85 is connected to the thread clamping solenoid 25 and drives the thread clamping solenoid 25 according to the control instructions of the CPU 91. The drive circuit 86 is connected to the display unit 15 and drives the display unit 15 according to the control instructions of the CPU 91.

[0038] Encoders 56-59, input units 16 and 19, pedal 18, and detector 49 are connected to I / O 95. Encoder 56 detects the rotational position and speed of the main shaft 31 connected to the output shaft of the main shaft motor 21 and inputs the detection results to I / O 95. Encoder 57 detects the rotational position and speed of the output shaft of the feed amount adjustment motor 24 and inputs the detection results to I / O 95. Encoder 58 detects the rotational position and speed of the output shaft of the alternating lift amount adjustment motor 23 and inputs the detection results to I / O 95. Encoder 59 detects the rotational position and speed of the output shaft of the pressing motor 22 and inputs the detection results to I / O 95. Input units 16 and 19 detect various instructions and input the detection results to I / O 95. Pedal 18 detects the direction and amount of pedal operation and inputs the detection results to I / O 95. Detector 49 inputs the detection results corresponding to the thickness of the sewn material to I / O 95.

[0039] Reference Figure 5 (a)~ Figure 7 The following examples are given for the following cases: Figure 5 As shown in (b), with a workpiece W1 placed on the needle plate 14 and the middle and outer presser levers 8 and 10 in the raised positions, after inputting the type of the workpiece W1, the operator P1 operates the pedal 18 to input an execution instruction for executing the presser foot lowering process. Upon detecting the execution instruction, the CPU 91 reads the program for lowering the sewing presser foot from the ROM 92 to the RAM 93 and executes the presser foot lowering process.

[0040] like Figure 6 and Figure 7 As shown, the CPU 91 refers to the error storage area 98 of the storage device 94 to determine whether an error is stored (S1). In S1, it can be determined whether an error has been stored during a given period, or it can be determined whether an error has been stored for the operator P1 who input the execution instruction. The CPU 91 of this embodiment determines whether an error has been stored for the operator P1 who input the execution instruction. In the error storage area 98, an error is stored for the operator P1 at date and time T1 (S1: Yes). Therefore, in order to draw the attention of the operator P1, the CPU 91 issues a warning before lowering the middle pressure rod 8 and the outer pressure rod 10 from the raised position (S2). The notification method of the warning in S2 can be set appropriately, for example, "The presser foot will be lowered, please pay attention."

[0041] If no error is stored (S1: NO), or after S2, the CPU 91 refers to the sewing condition storage area 97 of the storage device 94 and obtains a comparison range and threshold value (S3). The sewing condition storage area 97 of this embodiment pre-stores comparison ranges and threshold values ​​set for each workpiece type. Therefore, the CPU 91 calls up the comparison range and threshold value stored in the sewing condition storage area 97 of the storage device 94 according to the workpiece type. Specifically, from the multiple sets of comparison ranges and threshold values ​​stored in the sewing condition storage area 97, the CPU 91 obtains the comparison range R1 and threshold value K1 corresponding to the type of the workpiece W1 input at the start of the process. At least one of the comparison range and threshold value may be set for each operator P1 ID. In this case, for example, the CPU 91 may obtain the comparison range and threshold value corresponding to the operator ID.

[0042] The CPU 91 determines whether the detection positions of the intermediate pressure rod 8 and the external pressure rod 10 output by the detector 49 are within the comparison range R1 obtained in the process of S3 (S4). The process of S4 is to determine whether it is within the given period for lowering the intermediate pressure rod 8 and the external pressure rod 10 from the raised position. When the detection position is within the comparison range R1, that is, within the given period (S4: Yes), the CPU 91 controls the pressing motor 22 to lower the intermediate pressure rod 8 and the external pressure rod 10 at a first speed (S5). The method for controlling the lowering speed of the intermediate pressure rod 8 and the external pressure rod 10 can be appropriately selected according to the actuator that lowers the intermediate pressure rod 8 and the external pressure rod 10. For example, the CPU 91 controls the number of pulses per unit time output to the pressing motor 22 to lower the intermediate pressure rod 8 and the external pressure rod 10 at the first speed.

[0043] The CPU 91 calculates the estimated vertical positions of the intermediate pressure rod 8 and the external pressure rod 10 based on the drive amount of the pressing motor 22 (S6). The storage device 94 stores the relationship between the drive amount of the pressing motor 22 and the movement amounts of the intermediate pressure rod 8 and the external pressure rod 10, as well as the relative position of the raised position relative to a reference. The reference can be set as appropriate, for example, the upper surface of the needle plate 14. The storage device 94 calculates the estimated positions based on, for example, the movement amounts and raised positions of the intermediate pressure rod 8 and the external pressure rod 10 corresponding to the drive amount of the pressing motor 22.

[0044] The CPU 91 determines whether the absolute value of the difference between the detected position acquired in S4 and the estimated position calculated in S6 is greater than or equal to a threshold value K1 (S7). Normally, the absolute value of the difference between the detected position and the estimated position is close to zero. The threshold value is set to a value greater than 0 to account for errors in the calculation of the estimated position. If the absolute value of the difference is less than the threshold value K1 (S7: No), the CPU 91 returns the process to S4. In this case, the intermediate pressure lever 8 and the outer pressure lever 10 continue to descend at the first speed.

[0045] In the first case where the absolute value of the difference is greater than the threshold value K1 (S7: YES), the CPU 91 controls the pressing motor 22 to stop the intermediate and outer press rods 8 and 10 from descending and to raise them (S8). The CPU 91 preferably raises the intermediate and outer press rods 8 and 10 to a position sufficient to remove foreign matter, etc., from between the intermediate and outer presser feet 9 and 11 and the sewing material W1. The raising speed in S8 is preferably faster than the first speed. In this embodiment, the CPU 91 raises the intermediate and outer press rods 8 and 10 to the raised position.

[0046] CPU91 notifies that an error has occurred (S9). The notification method of S9 can be set appropriately. For example, CPU91 displays a message such as "Foreign matter is detected between the presser foot and the sewn object" on the display unit 15. CPU91 stores the situation in which the middle pressure rod 8 and the outer pressure rod 10 are raised as an error in the error storage area 98 of the storage device 94 (S10). Specifically, CPU91 stores the date and time when the error occurred in correspondence with information such as the operator ID in the error storage area 98 (S10). CPU91 updates the comparison range R1 (S11) based on the detection position when the absolute value of the difference between the detection position and the estimated position is greater than the threshold value in the processing of S7. The updating method of the comparison range can be set appropriately. For example, CPU91 can also Figure 5 As shown in the example of (b), if the position lowered by a distance E from the detection position F is located above the workpiece W1 placed on the needle plate 14, the range Rn1 from the position lowered by the distance E from the detection position F to the raised position is updated as the new comparison range. The CPU 91 completes the presser bar lowering process in the above manner.

[0047] When the detection position is not within the comparison range, that is, outside the given period (S4: No), the CPU91 controls the pressing motor 22 to lower the pressure rod at a second speed faster than the first speed (S12). The second speed only needs to be faster than the first speed, and is preferably a speed that is 1.2 times or more of the first speed. The CPU91 determines whether the descent has ended (S13). After the detection position is judged to be outside the comparison range, that is, outside the given period in S4, the CPU91 determines that the descent is ended if the descent of the middle pressure rod 8 and the outer pressure rod 10 stops based on the detection result of the detector 49. If the descent is not completed (S13: No), the CPU91 returns the processing to S13. Figure 5 As shown in (c) , when the intermediate presser foot 9 and the outer presser foot 11 are in contact with the workpiece W1 and the descent of the intermediate press bar 8 and the outer press bar 10 stops ( S13 : YES), the CPU 91 ends the press bar descent process by the above operation.

[0048] In the sewing device 1 of the above embodiment, the sewing device 1 is an example of a sewing device of the present invention. The needle bar 6 is an example of a needle bar of the present invention. The needle 7 is an example of a needle of the present invention. The middle presser bar 8 and the outer presser bar 10 are examples of presser bars of the present invention. The middle presser foot 9 and the outer presser foot 11 are examples of presser feet of the present invention. The needle plate 14 is an example of a needle plate of the present invention. The needle hole 20 is an example of a needle hole of the present invention. The spindle motor 21 is an example of a spindle motor of the present invention. The pressing motor 22 is an example of a pressing motor of the present invention. The needle bar mechanism 32 is an example of a needle bar mechanism of the present invention. The pressing mechanism 44 is an example of a pressing mechanism of the present invention. The detector 49 is an example of a detector of the present invention. The storage device 94 is an example of a storage unit of the present invention. The CPU 91 executing the process of S6 is an example of a calculation unit of the present invention. The CPU 91 executing the process of S3 is an example of a threshold value acquisition unit of the present invention. The CPU 91 executing the processes of S4, S5, S7, and S8 is an example of a presser bar control unit of the present invention. The CPU 91 executing the process of S11 is an example of a comparison range updating unit of the present invention. The CPU 91 executing the process of S10 is an example of a storage control unit of the present invention. The CPU 91 executing the process of S2 is an example of a warning notification unit of the present invention. The CPU 91 executing the process of S9 is an example of an error notification unit of the present invention. Distance D is an example of a distance of the present invention. Thickness J is an example of a thickness of the present invention. Comparison range R1 is an example of a comparison range of the present invention. Movable range RA is an example of a movable range of the present invention. Workpiece W1 is an example of a workpiece of the present invention.

[0049] The sewing device 1 of the above embodiment includes a needle bar 6, a needle bar mechanism 32, a spindle motor 21, a needle plate 14, an intermediate pressure rod 8, an external pressure rod 10, a pressing mechanism 44, a pressing motor 22, a detector 49, and a CPU 91. The needle bar 6 extends in the up-down direction, and a needle 7 can be mounted on the lower end. The needle bar mechanism 32 moves the needle bar 6 up and down. The spindle motor 21 drives the needle bar mechanism 32. The needle plate 14 is formed with a needle hole 20 through which the needle 7 can be inserted. The intermediate pressure rod 8 can be equipped with an intermediate presser foot 9 at the lower end, and the intermediate presser foot 9 is used to press the sewn object placed on the needle plate 14 from above. The external pressure rod 10 can be equipped with an external presser foot 11 at the lower end, and the external presser foot 11 is used to press the sewn object placed on the needle plate 14 from above. The pressing mechanism 44 moves the center press rod 8 and the outer press rod 10 vertically between an ascending position, in which the center presser foot 9 and the outer presser foot 11 are upwardly away from the needle plate 14, and a descending position, in which the center presser foot 9 and the outer presser foot 11 are positioned downward and closer to the needle plate 14 than when they are in the ascending position. The pressing motor 22 drives the pressing mechanism 44. The detector 49 detects the vertical position of the center press rod 8 and the outer press rod 10, i.e., the detected position. The CPU 91 calculates the estimated vertical position of the center press rod 8 and the outer press rod 10 based on the amount of drive of the pressing motor 22 (S6). The CPU 91 obtains a threshold value (S3). During a predetermined period of lowering the center press rod 8 and the outer press rod 10 from the ascending position, if the absolute value of the difference between the detected position and the estimated position is greater than the threshold value (S4: Yes, S7: Yes), the CPU 91 controls the driving of the pressing motor 22 to raise the center press rod 8 and the outer press rod 10 (S8). In the second case where the absolute value of the difference between the detected position and the estimated position is less than the threshold value (S4: Yes, S7: No), the CPU 91 controls the driving of the pressing motor 22 to lower the intermediate presser 8 and the outer presser 10 (S5). In the case where a foreign object is caught between the intermediate presser foot 9 and the outer presser foot 11 and the needle plate 14, the sewing device 1 sets the threshold value so that the absolute value of the difference between the detected position and the estimated position is greater than the threshold value. This helps prevent sewing from being performed with a foreign object caught between the intermediate presser foot 9 and the outer presser foot 11 and the needle plate 14.

[0050] The predetermined period of the sewing device 1 is the period during which the intermediate pressure lever 8 and the outer pressure lever 10 are located within a comparison range, which is defined as a portion of the movable range RA from the raised position to the lowered position. Compared to determining whether the absolute value of the difference between the detected position and the estimated position is greater than or equal to a threshold value within the entire movable range RA of the intermediate pressure lever 8 and the outer pressure lever 10, the CPU 91 executing the processes of S4, S5, S7, and S8 of the sewing device 1 facilitates simplifying the processing performed in the processes of S4, S5, S7, and S8.

[0051] The comparison range R1 of the sewing device 1 is a range in which the distance D in the vertical direction from the needle plate 14 to the comparison range R1 is greater than the thickness J of the sewn article W1. The CPU 91 that executes the processes S4, S5, S7, and S8 of the sewing device 1 helps to avoid the following situation: when no foreign matter is clamped between the middle presser foot 9 and the outer presser foot 11 and the needle plate 14, and the middle presser bar 8, the middle presser foot 9, and the outer presser foot 11 are in contact with the sewn article, and accordingly, when the absolute value of the difference between the detected position and the estimated position is greater than a threshold value, the middle presser bar 8 and the outer presser bar 10 rise.

[0052] When lowering the intermediate press rod 8 and the outer press rod 10 from the raised position, the CPU 91 of the sewing device 1 lowers the intermediate press rod 8 and the outer press rod 10 at a first speed (S5) when the estimated position is within the comparison range R1 (S4: Yes) and in the second condition (S7: No). When the estimated position is outside the comparison range (S4: No), the CPU 91 lowers the intermediate press rod 8 and the outer press rod 10 at a second speed that is faster than the first speed (S12). Within the comparison range R1, where there is a possibility of foreign matter being caught between the intermediate presser foot 9 and the outer presser foot 11 and the needle plate 14, the CPU 91 lowers the intermediate press rod 8 and the outer press rod 10 more slowly than outside the comparison range R1. This helps to suppress the impact of the intermediate presser foot 9 and the outer presser foot 11 colliding with foreign matter. Compared with the case where the middle pressure rod 8 and the outer pressure rod 10 also descend at the first speed outside the comparison range R1, the CPU 91 of the sewing device 1 helps to shorten the time required for the middle pressure rod 8 and the outer pressure rod 10 to finish descending.

[0053] The CPU 91 of the sewing device 1 updates the comparison range (S11) based on the detection position in the first case (S7: Yes). The CPU 91 of the sewing device 1 that performs the process of S11 updates the comparison range based on the detection position in the first case, thereby contributing to more accurately detecting the situation where a foreign object is clamped between the middle presser foot 9 and the outer presser foot 11 and the needle plate 14.

[0054] The CPU 91 of the sewing device 1 stores the fact that the intermediate press rod 8 and the outer press rod 10 were raised in the first case (S7: Yes) as an error in the error storage area 98 of the storage device 94 (S10). When the storage device 94 stores an error (S1: Yes), the CPU 91 issues a warning before lowering the intermediate press rod 8 and the outer press rod 10 from the raised position (S2). The processes of S1, S2, and S10 of the sewing device 1 call attention to the recurrence of the error through the warning, thereby helping to prevent the process of lowering the intermediate press rod 8 and the outer press rod 10 from the raised position from being started when a foreign object, for example, is trapped between the intermediate presser foot 9 and the outer presser foot 11 and the needle plate 14.

[0055] The sewing condition storage area 97 of the storage device 94 of the sewing device 1 pre-stores comparison ranges and threshold values ​​set for each type of workpiece. The CPU 91 calls the comparison range and threshold value stored in the sewing condition storage area 97 of the storage device 94 based on the type of workpiece. Within a predetermined period (S4: Yes), the CPU 91 raises the intermediate pressure lever 8 and the outer pressure lever 10 in the first case (S7: Yes) and lowers them in the second case (S7: No) (S4, S5, S7, S8). This facilitates the appropriate execution of S4-S8, compared to executing S4-S8 using the same comparison range and threshold value regardless of the type of workpiece.

[0056] In the first case (S7: YES), the CPU 91 of the sewing device 1 notifies the operator of the occurrence of an error when the middle pressure lever 8 and the outer pressure lever 10 are raised (S9). The CPU 91 of the sewing device 1 that executes the process of S9 notifies the operator of the occurrence of an error, which helps to encourage the operator to deal with the error appropriately.

[0057] The present invention is not limited to the above-described embodiment. The type of sewing device 1 can be appropriately modified to include a lockstitch sewing machine, a top-and-bottom feed sewing machine, or the like. The sewing device 1 may also be devoid of the intermediate pressure rod 8 and the intermediate presser foot 9. The method by which the detector 49 detects the vertical position of the intermediate pressure rod 8 and the outer pressure rod 10 can be appropriately modified. For example, it can be an optical, eddy current, ultrasonic, or contact proximity displacement sensor. The configuration and detection timing of the detector 49 can be appropriately modified.

[0058] The program containing the instruction for causing the sewing device 1 to execute the pressure bar lowering process can be stored in the storage device 94 of the sewing device 1 before the CPU 91 executes the program. Therefore, the method for obtaining the program, the acquisition path, and the device for storing the program can be appropriately changed. The program executed by the CPU 91 can also be received from other devices via a cable or wireless communication and stored in a storage device such as a flash memory. Other devices include, for example, a PC and a server connected to the sewing device 1 via a network.

[0059] Part or all of the processing performed by the sewing device 1 may be performed by an electronic device different from the CPU 91 (e.g., an ASIC). The processing performed by the sewing device 1 may also be distributed among multiple electronic devices (e.g., multiple CPUs). The order of each step of the processing performed by the sewing device 1 can be changed, steps can be omitted, or steps can be added as needed. The scope of the present invention also includes a mode in which an operating system (OS) running on the sewing device 1 performs part or all of the processing according to instructions from the CPU 91. For example, the sewing device 1 may appropriately add the following changes to the above-mentioned embodiment.

[0060] The lowering speeds of the middle and outer pressure bars 8 and 10 can be appropriately changed, and the first speed can be set to be higher than the second speed. At least one of the first and second speeds can also be set in accordance with at least one of the operator ID and the type of sewing material. For example, when the pressure bar lowering process is executed based on an execution instruction from an operator with an error stored, the first speed can be reduced compared to when the pressure bar lowering process is executed based on an execution instruction from an operator without an error stored.

[0061] The CPU 91 may also omit the process (S11) of updating the comparison range based on the detected position in the first case (S7: Yes). The CPU 91 may also omit the process (S10) of storing the fact that the intermediate pressure lever 8 and the external pressure lever 10 were raised in the first case (S7: Yes) in the error storage area 98 of the storage device 94 (S10), and omit the process (S2) of issuing a warning before lowering the intermediate pressure lever 8 and the external pressure lever 10 from the raised position when the storage device 94 stores an error (S1: Yes). The CPU 91 may also omit the process (S9) of notifying that an error has occurred when the intermediate pressure lever 8 and the external pressure lever 10 are raised in the first case (S7: Yes).

[0062] The sewing device 1 may not store sewing conditions corresponding to the category of the sewn object, and the sewing conditions may not include at least one of the comparison range and the threshold value. For example, the sewing device 1 may also set the value input by the operator via the input unit 16 before the sewing work to at least one of the comparison range and the threshold value. The given period of the sewing device 1 can be appropriately changed, and may not be a period set based on whether the detection result of the detector 49 is within the comparison range. For example, the given period may also be a period set by the elapsed time from the start of the descent from the rising position. The comparison range may be set to the entire movable range RA from the rising position to the descending position, or it may be a range in which the distance D in the vertical direction from the needle plate 14 to the comparison range R1 is less than the thickness J of the sewn object W1.

Claims

1. A sewing device, characterized in that: have: The needle bar extends in the up-down direction and the needle can be mounted at the lower end; a needle bar mechanism that moves the needle bar up and down; a spindle motor driving the needle bar mechanism; a needle plate having a needle hole formed thereon for the needle to be inserted through; A presser bar, at the lower end of which a presser foot can be mounted, for pressing the sewn material placed on the needle plate from above using the presser foot; a pressing mechanism that causes the presser rod to move up and down between an ascending position and a descending position, wherein the ascending position is a position where the presser foot is above the needle plate and away from the needle plate, and the descending position is a position below the presser foot and closer to the needle plate than when the presser foot is in the ascending position; a pressing motor driving the pressing mechanism; a detector that detects a detection position as a position of the pressing rod in the up-down direction; a calculation unit that calculates an estimated position of the pressing rod in the vertical direction estimated based on a driving amount of the pressing motor; a threshold value acquiring unit, which acquires a threshold value; as well as A pressure rod control unit controls the drive of the pressing motor, and during a given period of lowering the pressure rod from the rising position, in a first case where the absolute value of the difference between the detected position and the estimated position is greater than the threshold value, causes the pressure rod to rise, and in a second case where the absolute value of the difference between the detected position and the estimated position is less than the threshold value, causes the pressure rod to fall.

2. The sewing device according to claim 1, characterized in that The predetermined period is a period during which the press rod is located in a comparison range, and the comparison range is set as a portion of a movable range from the raised position to the lowered position.

3. The sewing device according to claim 2, characterized in that: The comparison range is a range in which a distance in the vertical direction from the needle plate to the comparison range is greater than a thickness of the sewn article.

4. The sewing device according to claim 2 or 3, characterized in that: When lowering the pressure rod from the raised position, the pressure rod control unit lowers the pressure rod at a first speed when the estimated position is within the comparison range and in the second condition. When lowering the press rod from the raised position, the press rod control unit lowers the press rod at a second speed faster than the first speed if the estimated position is outside the comparison range.

5. The sewing device according to claim 2 or 3, characterized in that: The sewing device further includes a comparison range updating unit configured to update the comparison range based on the detection position in the first case.

6. The sewing device according to any one of claims 1 to 3, characterized in that: The sewing device also includes: a storage control unit configured to store, as an error, a fact that the pressure rod is raised in the first case in a storage unit; and A warning notifying unit notifies a warning before lowering the press rod from the raised position when the error is stored in the storage unit.

7. The sewing device according to claim 2 or 3, characterized in that: The sewing device further includes a storage unit that stores in advance the comparison range and the threshold value set for each type of the sewn object. The press bar control section raises the press bar in the first case and lowers the press bar in the second case within the given period according to the type of the sewn workpiece and based on the comparison range and the threshold value stored in the storage section.

8. The sewing device according to any one of claims 1 to 3, characterized in that: The sewing device further includes an error notification unit configured to notify that an error has occurred when the press bar is raised in the first situation.

Images