JP2016168119A - Upper feeding device of sewing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an upper feeding device of a sewing machine in which a pressing pressure to a cloth by an upper feed dog is constant even when there is a level difference in a cloth irrespective of thickness of the cloth to be sewn so that there is no risk of occurrence of a feeding scratch due to a pressing pressure becoming too intense and there is no risk of occurrence of sewing jam due to reverse feed happening by being pushed back when the upper feed dog is abutted with the level difference.SOLUTION: An upper feeding device of a sewing machine has a lever 22 for oscillating by a vertical movement mechanism for vertically moving an upper feed dog 12 being interlocked with an upper shaft. In the lever 22, one end is pivotally attached to a block 21 fixed to an upper feed adjustment shaft 27 supported so as to ascend/descend, the other end can ascend/descend and can be tilted back and forth, and it is connected by an upper feed shaft 11 in which the upper feed dog 12 is attached at a lower end, and a link 25. The upper feed adjustment shaft 27 is connected to a piston rod 30 of an air cylinder 29, an air pressure of the air cylinder 29 is maintained at a constant pressure by a regulator 30, and pressing to a cloth by the upper feed dog 12 is maintained to be constant.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an upper feed device of a sewing machine provided with a forward / backward movement mechanism and an up / down movement mechanism of an upper feed dog.

  In Patent Document 1 below, as an upper feed device of this type of sewing machine, a cylindrical piece-shaped bearing attached to a sewing machine frame so as to be rotatable around a horizontal axis, and slidably penetrated in the diameter direction of the bearing. And an upper feed shaft having an upper feed dog attached to the lower end, and a longitudinal movement mechanism and a vertical movement mechanism that connect the upper feed shaft and the upper shaft (drive shaft). And a forward / backward feed shaft that reciprocates (swings) by rotation of the shaft, a crank that is fixed to the forward / backward feed shaft, and a link that connects the crank and a curved rod that extends upward from the upper feed shaft. The upper feed shaft is tilted back and forth while rotating the bearing due to the swing of the crank, so that the upper feed dog is moved back and forth, while the vertical movement mechanism is moved by the rotation of the upper shaft. A swinging vertical feed shaft, a crank fixed to the vertical feed shaft, A crank lever mechanism composed of a lever coupled with a rank and swinging in conjunction with a crank; an upper and lower pin rotatably attached to the curved rod around a horizontal axis; and a link of the crank lever mechanism A lifting rod that is pivotally attached to a pin that pivotally connects one end of the lever, and a lower portion that is slidably inserted into a protruding portion that protrudes laterally from the curved rod, a nut for attachment to the rod, and the A first spring is mounted on a lifting rod between the projecting portions of the upper and lower pins and biases the rod in a direction to push up the rod. The other end of the lever of the vertical movement mechanism is always a second spring. Is pivotally attached to the block supported by being pushed down by the stopper and pressed by the stopper. When the upper feed dog hits the step of the cloth during sewing, the upper feed shaft is attached to the first feed with the upper feed dog. Spring Ascending while compressing, at a higher stage, the block is lifted from the stopper while compressing the second spring, whereby the lifting rod is lifted together with the pin connecting the rod and the lever, and the upper feed shaft and the upper feed dog Has been disclosed that can further increase.

  In addition to the sewing machine top feed device, a front / rear feed shaft that is connected to a top feed base having an upper feed dog attached thereto, and a longitudinal movement mechanism for moving the top feed base back and forth swings in conjunction with the drive shaft, A vertical movement mechanism that consists of a crank that is fixed to the feed shaft and swings in the cloth feed direction and is connected to the upper feed base. The upper feed base moves back and forth by the swing of the crank, while the upper feed base moves up and down. Has a guide groove that slidably fits the upper feed table in the front-rear direction, a vertical feed shaft that swings in conjunction with the drive shaft, and a vertical feed shaft that is fixed to the feed shaft and swings up and down. A crank that is connected to the guide and tilts the guide up and down together with the upper feed base and moves the upper feed dog up and down by tilting the upper feed base up and down is known.

JP 7-328258 A

  In the upper feed device of the sewing machine, the upper feed dog performs elliptical motion and cooperates with the lower feed dog to feed the fabric with the upper and lower feed dogs sandwiching the cloth. In the device disclosed in Patent Document 1, the presser is performed by the action of the first spring and then the second spring applied to the spring, and the presser pressure at this time increases as the cloth becomes thicker. If there is a step, it becomes even stronger, and when the cloth is fed, the upper feed dog that performs elliptical motion is the strongest when the lower feed dog is at the top dead center. If the pressing force for sandwiching the cloth from above and below becomes too strong, there will be a disadvantage that the feed flaw is generated by the cloth.

  In particular, when sewing a step with a thick cloth, if the amount of rise in the elliptical motion of the upper feed dog is insufficient and the step hits the upper feed dog, the fabric is pushed back in the opposite direction to the cloth feed and reverse feed is performed. There is a risk of sewing clogging.

  It is an object of the present invention to provide a top feed device for a sewing machine that does not cause problems such as feed flaws and stitching even if the thickness of the cloth changes.

  The upper feed device of the invention according to claim 1 is provided with an upper feed dog, and is supported by an upper feed shaft that can be moved up and down and tilted back and forth, or a guide that can be tilted up and down and slidable back and forth. Connected to a base, the upper feed shaft or the upper feed base, and to move the upper feed dog back and forth in the cloth feed direction, and connected to the upper feed shaft or guide to move the upper feed dog up and down The vertical movement mechanism comprises an upper feed adjusting shaft supported by the sewing machine frame so as to be movable up and down, and one end pivotally attached to the upper feed adjusting shaft or a block fixed to the shaft. A lever that swings in conjunction with the drive shaft of the sewing machine, a link mechanism that connects the other end of the lever and the upper feed shaft or guide, and a first air in which a piston rod is connected to the upper feed adjustment shaft. Including cylinder, air cylinder and compressor Provided pressure circuit, and having a first pressure means for maintaining the air pressure within said first air cylinder at the set pressure.

According to a second aspect of the present invention, in the first aspect of the invention, the presser foot having a presser foot attached to the lower end thereof is pressed by the piston rod of the second air cylinder to perform the presser foot with the presser foot. A second constant pressure means is provided in a pneumatic circuit including two air cylinders and the compressor to maintain the air pressure in the second air cylinder at a set pressure;
The invention according to claim 3 is the invention according to claim 2, wherein the feed adjusting shaft forms a double shaft structure with the presser shaft.

  The invention according to claim 4 is characterized in that, in the inventions according to claims 1 to 3, at least the first constant pressure means of the first and second constant pressure means can adjust the set pressure.

  The invention according to claim 5 is the invention according to any one of claims 1 to 3, wherein a control unit for controlling the piston position of the first air cylinder is provided, and the step portion of the cloth is detected by the detecting means for detecting the step portion of the cloth. The control unit controls the piston position of the first air cylinder when detecting this.

  According to the first aspect of the present invention, when the vertical position of the upper feed dog is displaced depending on the thickness of the cloth, one end of the lever is lifted or lowered together with the upper feed adjustment shaft, and accordingly, the piston rod of the first air cylinder However, since the piston rod is maintained at a constant pressure in the first air cylinder regardless of the vertical position, the pressing force applied to the upper feed shaft or guide by the air cylinder via the lever is constant. It is maintained, and the presser against the cloth by the upper feed dog is also maintained constant. Similarly, if there is a step in the fabric to be sewn, the upper feed dog is lifted according to the step height, and the piston rod rises. The pressing force on the cloth does not change. Therefore, even if the feed dog hits the step, the pressing force on the cloth is kept constant and the transfer is performed, so that the sewing jam does not occur.

  According to the second aspect of the present invention, the pressing force against the cloth by the presser foot can be kept constant regardless of the thickness of the cloth and even if there is a step.

According to the invention according to claim 3, space saving is enabled by making the upper feed adjusting shaft and the presser shaft into a double shaft structure,
In the invention according to claim 4, of the upper feed dog and the presser foot, at least the upper feed dog can arbitrarily set the pressing force to the cloth.

  According to the invention which concerns on Claim 5, when the step part of the cloth is detected by the detection means, the piston position is changed, and the vertical position of the upper feed dog can be changed.

The side view of the main mechanism of a sewing machine head. The front view. The figure which shows the pneumatic circuit of an upper feed dog and a presser foot. Schematic of the mechanism which controls raising / lowering of an upper feed dog according to cloth thickness.

Hereinafter, an upper feed device of a sewing machine according to an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a side view of various mechanisms and devices provided in the sewing machine head, FIG. 2 is a front view of the same, and the various mechanisms and devices include a needle mechanism, an upper feed device, and a presser foot device. Since the sewing machine is a flat stitch sewing machine, it has an upper decorative thread mechanism. Of these, the needle mechanism and the upper decoration thread mechanism are known and unchanged, and are not characteristic features of the present invention, so a detailed description is omitted, but the needle mechanism is an upper shaft that is a drive shaft. The needle bar which is driven by the needle bar and moves up and down, and a plurality of needles 1 attached to the needle stock at the lower end of the needle bar, and the upper decoration thread mechanism is also driven by the upper shaft and swings (reciprocates). An upper decorative shaft 3 and a decorative yarn spreader 4 fixed to the lower end of the upper decorative shaft are provided.

  The upper feed device penetrates through a cylindrical piece-shaped bearing 9 that is attached to the machine frame 8 of the sewing machine head so as to be able to rotate laterally and perpendicularly to the cloth feed. The upper feed shaft 11 has a top feed shaft 11 that tilts back and forth and moves up and down by sliding on the bearing 9. The top feed shaft 11 is attached to the lower end of the top feed shaft 11 in conjunction with the top shaft. And a vertical movement mechanism that moves the upper feed dog 12 up and down in conjunction with the upper shaft.

  The back-and-forth movement mechanism is the same as the mechanism disclosed in Patent Document 1, and is a back-and-forth feed that is pivotally supported in a direction that is parallel to the bearing 9 and orthogonal to the cloth feed, and swings in conjunction with the upper shaft. The shaft 14, the crank 15 fixed to the longitudinal feed shaft 14, the curved rod 16 extending integrally with the upper feed shaft 11 upward from the upper feed shaft 11, and the crank 15 and the curved rod 16 are connected. A crank lever mechanism composed of a link 17 is configured, and the upper feed shaft 11 integrated with the curved rod 16 is tilted back and forth while rotating the bearing 9 by the swing of the front and rear feed shaft 14. The upper feed dog 12 is moved back and forth.

  The vertical movement mechanism is parallel to the bearing 9 and the front / rear feed shaft 14, is rotatably supported by the machine frame, and swings in conjunction with the upper shaft. A crank lever mechanism comprising a fixed crank 20, a lever 22 whose one end is rotatably supported by the block 21, and a link 23 connecting the other end of the lever 22 and the crank 20, is constructed. Further, the pin 24 that pivotally attaches the link 23 is further pivotally attached to the upper end of the upper feed shaft 11, and a link 25 as a link mechanism that connects the pin 24 and the upper end of the upper feed shaft 11 is pivotally supported. When the lever 22 swings in conjunction, the upper feed shaft 11 moves up and down through the bearing 9 via the link 25 and moves the upper feed dog 12 up and down.

  The vertical movement mechanism of the upper feed dog 12 described above is the same as the mechanism disclosed in Patent Document 1, and is the same as that of Patent Document 1, but the block support means is different. That is, while the block in Patent Document 1 is pushed down by the second spring, the block 21 of the present embodiment is moved up and down to the machine frame 8 of the sewing machine head as shown in FIGS. The upper feed adjustment shaft 27 is fixed to a lower end of a hollow shaft-like upper feed adjustment shaft 27 that is supported, and a support mechanism is connected to the upper feed adjustment shaft 27. The support mechanism includes a piston rod 30 of a double-acting first air cylinder 29 attached to a bracket 28 protruding from a machine frame 8 at the head of the sewing machine, and a machine frame 8 of the upper feed adjusting shaft 27. The connecting plate 31 that connects the protruding portion 27a that protrudes further, and a compressor 32 and a regulator 33 that form a pneumatic circuit together with the first air cylinder 29, the regulator 33 maintains the air pressure of the air cylinder 29 at a set pressure. The first constant pressure means is configured, and the upper feed adjusting shaft 27 is pushed down with a set pressure regardless of the position of the piston (not shown) of the air cylinder 29, and the upper feed dog 12 is always pressed with a set pressing force. To hold down. The regulator 33 is a known one, and the set pressure can be changed. However, a regulator that cannot change the set pressure can also be used.

  In the present embodiment, one end of the lever 22 is pivotally attached to the block 21, but it is also possible to directly attach to the upper feed adjusting shaft without the block 21.

  The vertical movement mechanism of the present embodiment is configured as described above, and causes the upper feed dog 12 to perform an elliptical motion including forward and backward movement and vertical movement in cooperation with the forward and backward movement mechanism, and in cooperation with the lower feed dog 35. When the upper feed dog 12 is moved up and down depending on the thickness of the cloth to be sewn, the link 25 lifts or depresses the lever 22 while tilting the link 23 up and down, thereby adjusting the upper feed together with the block 21. The shaft 27 is moved up and down to raise and lower the piston rod 30 and a piston (not shown) at the end of the rod.

  Even if the lever 22 pivoted on the block 21 is lifted or pushed down as described above and the position of the pin 24 moves up and down, the swing amount of the lever 22 swung by the crank 20 does not change. There is no change in the amount of vertical movement of the feed shaft 11. Therefore, the upper feed dog 12 moves up and down by the same amount regardless of the thickness of the cloth, and performs the same elliptical motion in combination with the forward and backward movement.

  Even if there is a step on the cloth to be sewn, the upper feed dog will rise and get over the step within the range of the stroke of the piston, press the cloth while maintaining the set pressing force, and feed the fabric. Then, the step does not sink under the upper feed dog, and the upper feed dog hits the step and the fabric is pushed back in the opposite direction to the fabric feed, causing reverse feed, which may cause stitch jamming. The problem is that when a detection means for detecting the step of the cloth, for example, a detection sensor for the cloth step as shown in FIG. 4 is provided and the sensor detects the step, the piston position of the first air cylinder 29 is increased. This can be solved by switching to the position.

  4 includes a light emitting unit 35 and a light receiving unit 36. The cloth 38 to be sewn is thin, and the light receiving unit 36 emits light emitted from the light emitting unit 35. When detected, the control unit 37 for switching and controlling the piston position of the first air cylinder 29 between the upper position and the lower position switches the piston to the lower position and lowers the upper feed dog 12 while the cloth is thick. Alternatively, when there is a step as shown in the figure and the light receiving unit 36 stops detecting the light from the light emitting unit 35, the piston position is switched to the upper position and the upper feed dog 12 is raised.

  In addition to the transmission type optical sensor as shown in FIG. 4, for example, a contact type sensor that turns on the control unit 37 when it touches the cloth to be sewn and hits the stepped portion and is lifted by a certain amount is used. An operation to turn on the control unit 37 when a step for which a sewing manufacturer determines that it is necessary to lift the upper feed dog is provided without using a sensor as described above. May be performed. In this case, therefore, detection of the stepped portion by the visual inspection of the sewing manufacturer becomes the detection means. Note that the upper feed dog 12 does not change in the vertical momentum as well as the longitudinal momentum, regardless of whether it is in the lowered position or the raised position as described above.

Next, the presser foot device will be described.
The presser shaft 40 having a presser foot 39 attached to the lower end is fixed by inserting the lower side of the presser adjusting shaft 41 having a smaller diameter than the presser shaft 40 (the presser shaft 40 and the presser adjusting shaft 41 are integrally formed. However, the upper part of the presser adjusting shaft 41 is passed through a hollow upper feed adjusting shaft 27 so that it can be moved up and down. A single-acting second air cylinder 43 is attached to the bracket 28 along with the first air cylinder 29, and a piston rod 44 of the air cylinder 43 is inserted into the upper feed adjusting shaft 27 to adjust the presser foot. The shaft 41 is butted against the shaft end.

  Similarly to the first regulator 33, the second air cylinder 43 constitutes a pneumatic circuit together with a regulator 44 as a second constant pressure means for maintaining the air pressure of the air cylinder 43 at a set pressure, and the compressor 32. The piston rod 44 of 43 pushes down the presser shaft 40 via the presser adjusting shaft 41 so that the presser foot 39 can be pressed against the cloth with a constant pressing force regardless of the thickness of the cloth.

  Although not shown, the vertical feed shaft 19 is passed through a hollow outer shaft to form a double shaft structure and can be rotated separately from the outer shaft. When the lever 46 is moved up and down through the link 45 and the cloth is inserted under the presser foot or the presser foot is raised and lowered for sewing, the presser shaft 40 is lifted or lowered to press the presser foot. 39 so that the presser foot 39 can be moved up and down according to the thickness of the cloth during sewing so that the lever 46 has a vertical hole 47, A set screw 48 is fixed to the presser shaft 40 through the vertical hole 47, and the presser shaft 40 can be moved up and down without moving the lever 46 within the range of the vertical hole 47.

  In the above-described embodiment, the regulators 33 and 44 are exemplified as the constant pressure means. However, for example, a relief valve can also be used. Many of the relief valves can adjust the set pressure by changing the spring pressure, like the regulators 33 and 44, but the set pressure may not be changed.

  In the embodiment, the longitudinal feed shaft 14, the crank 15, the link 17 and the curved rod 16 and the vertical feed shaft 19, the crank 20, the link 23 and the lever 22 constitute a crank lever mechanism. The mechanism is not limited to the crank lever mechanism as described above as long as it is a mechanism that causes the same motion to be performed by the motor 22. For example, a mechanism comprising an eccentric ring fixed to the feed shafts 14 and 19, a rod fitted at one end to the eccentric ring, and a curved rod 16 or a lever 22 connected to the rod can be used.

  The above is an example in which the present invention is applied to an upper feed device in which a vertical movement mechanism and a longitudinal movement mechanism are connected to the upper feed shaft 11 and the upper feed shaft 11 is moved up and down and tilted back and forth by these mechanisms. An upper feed base with teeth is slidably fitted to the guide, and the guide is slid back and forth by swinging the crank fixed to the front and rear feed shaft, while the vertical movement is linked to the vertical feed shaft. The same applies to an upper feed device of a type in which the guide is tilted up and down together with the upper feed base. In this case, as a mechanism for moving the upper feed base up and down, the vertical movement mechanism of the upper feed shaft 11 of the above embodiment. The same can be used. That is, the vertical movement mechanism has one end pivotally attached to the upper feed adjustment shaft 27 or the block 21 fixed to the adjustment shaft, and swings in conjunction with the vertical feed shaft 19, and the other end of the lever 22 The guide is composed of a link for connecting the guide, and the guide is tilted up and down together with the upper feed base by the swing of the lever 22.

  In the above-described embodiment, the regulators 33 and 44 are exemplified as the constant pressure means. However, for example, a relief valve can also be used. As with the regulators 33 and 44, the relief valve can also adjust the set pressure by changing the spring pressure, but the set pressure may not be changed.

  Although the example in which the upper feed device of the above embodiment is applied to a flat stitch sewing machine has been shown, the sewing machine can be applied to any sewing machine as long as the upper feed device is provided.

8 .. Machine frame 9.. Bearing 11... Top feed shaft 12... Top feed gear 14 .. Front and rear feed shaft 19 .. Vertical feed shaft 20 .. Crank 21. Link 27 ··· Top feed adjusting shaft 29 · · First air cylinder 30 and 44 · · Piston rod 32 · Compressor 33 and 44 · · Regulator 35 · · Light emitting portion 36 · · Light receiving portion 37 · · Control portion 39 · · Presser foot 40 · · Presser shaft 41 · · Presser adjusting shaft 43 · · Second air cylinder

Claims (5)

  An upper feed shaft provided with an upper feed dog and capable of moving up and down and tilting back and forth, or an upper feed base supported slidably back and forth by a guide tiltable up and down, and connected to the upper feed shaft or the upper feed base A vertical movement mechanism that moves the upper feed dog back and forth in the cloth feed direction, and a vertical movement mechanism that is connected to the upper feed shaft or guide and moves the upper feed dog up and down. An upper feed adjusting shaft supported by the frame so as to be movable up and down, and a lever that is pivotally attached to the upper feed adjusting shaft or a block fixed to the shaft so as to be pivotable and swings in conjunction with the drive shaft of the sewing machine. A link mechanism for connecting the other end of the lever to the upper feed shaft or guide, a first air cylinder having a piston rod connected to the upper feed adjustment shaft, and a pneumatic circuit including the air cylinder and a compressor. The first air cylinder Upper feed device of the sewing machine, characterized in that it comprises a first pressure means for maintaining the air pressure within the over to the set pressure.   The presser foot with the presser foot attached to the lower end is pressed by the piston rod of the second air cylinder to perform the presser foot with the presser foot, and the second constant pressure is applied to the pneumatic circuit including the second air cylinder and the compressor. The upper feed apparatus of the sewing machine according to claim 1, wherein means is provided to maintain the air pressure in the second air cylinder at a set pressure.   The upper feed apparatus of the sewing machine according to claim 2, wherein the feed adjusting shaft forms a double shaft structure with the presser shaft.   The upper feed apparatus of the sewing machine according to claim 2 or 3, wherein at least the first constant pressure means among the first and second constant pressure means can adjust a set pressure.   According to a fifth aspect of the present invention, there is provided a control unit that controls the piston position of the first air cylinder, and the control unit detects the first step of the cloth when the first step of the cloth is detected by the detecting means that detects the first step of the cloth. The upper feed device of the sewing machine according to any one of claims 1 to 3, wherein a piston position of the air cylinder is controlled.