JPH11244563A - Center presser bar mechanism for sewing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify center presser mechanism of a cycle sewing machine capable of providing seams along an optional shape within a specified range of material to be sewn. SOLUTION: Center presser mechanism has a center presser vertical moving part 20 lowering a center presser 12 during sewing and raising it during stop, and a center presser sewing action part 30 for vertically moving the center presser 12 in correspondence with a needle during sewing. The motion of the center presser vertical moving part 20 and center presser sewing action part 30 for vertically moving the center presser 12 is transmitted to the center presser 12 by one center presser link 40. The center presser sewing action part 30 has a center presser cam 31 provided at an upper shaft 3, and a center presser driving arm 32 to be a follower of the center presser cam 31. The center presser cam 31 can retreat backward along the upper shaft 3 from a contact position with the center presser driving arm 32. The center presser cam 31 is retreated and separated from the center presser driving arm 32 to stop the vertical motion of the center presser 12 during sewing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a middle presser mechanism for a sewing machine which can provide a stitch along an arbitrary shape within a predetermined range of a workpiece.

[0002]

2. Description of the Related Art In general, a cycle sewing machine capable of providing stitches along an arbitrary shape within a predetermined range of a workpiece (cloth, cloth, etc.) is a method of holding a workpiece by, for example, holding a frame-shaped upper and lower part. It has holding means for holding and holding with a plate (cloth press outer frame and lower plate), and a feed mechanism for moving the holding means in a horizontal plane perpendicular to the sewing machine needle. An arbitrary position of the sewn object in the pressed and stretched state can be stabbed with a sewing needle.

That is, in the above-described cycle sewing machine, the sewing position can be changed for each stitch by changing the sewing position in an arbitrary range with respect to the sewing needle in an arbitrary range, so that the stitch can be formed in an arbitrary shape. For example, stitches along contour lines of various marks or stitches of a predetermined shape (for example, stitching of a seat belt) can be formed. It has become.

[0004] In the above cycle sewing machine,
Since the cloth is held outside the predetermined range by the frame-shaped upper and lower holding plates, the sewing machine needle is moved downward to pierce the sewing object and then lift the needle. Since the portion where the sewing needle is stabbed is pulled upward, an intermediate presser is provided in the vicinity of the sewing needle for pressing the workpiece downward. Also, since the intermediate presser presses the workpiece down in the vicinity of the sewing needle, the position of the intermediate presser on the plane is basically fixed with respect to the position of the sewing needle, and the holding means is horizontal. By moving in the direction, the intermediate presser does not move even if the sewing object moves.

[0005] Therefore, if the intermediate presser keeps pushing the workpiece downward while moving the workpiece, the movement of the workpiece may be hindered by the intermediate presser. So, the middle presser
It is designed to move up and down in response to the vertical movement of the sewing needle, and when the sewing needle moves up and the sewing object moves,
The intermediate presser also rises upward. In addition, such an operation of the intermediate presser is performed using the upper shaft that transmits power to the sewing machine needle, and the rotation of the upper shaft moves the sewing machine needle up and down, and the intermediate presser moves up and down. It has become. When the sewing machine is stopped, the intermediate presser is largely raised so that the sewing object can be attached to and detached from the holding means. During sewing, the intermediate presser lowers to hold the sewing object as described above. When the workpiece is moved, it rises slightly and does not hinder the movement of the workpiece.

[0006]

By the way, there are also types of intermediate pressers. Some intermediate pressers are designed to be used while pressing the sewing object even when the sewing object is moved. Some of them do not require the middle presser to be moved up and down in response to the vertical movement of the sewing needle. In other words, when large friction does not occur between the lower surface of the intermediate presser and the work to be sewn, even if the intermediate presser presses the work to be sewn down during sewing, As a result, the movement of the sewing object is not hindered.

Therefore, when the type of the intermediate presser can be changed, it is necessary that the operation mechanism of the intermediate presser can perform two kinds of different operations. It was complicated. Also, when you see the operation of the normal presser foot, the operation includes lowering the presser foot at the start of sewing, raising the presser foot when sewing is stopped, and moving the presser up and down during sewing. There are two types of operations to be performed, and the operation mechanism is complicated to perform the two types of operations.

In the operation of the intermediate presser, an eccentric cam for the intermediate presser provided on the upper shaft is used, and a spring is used, so that the top dead center of the needle and the upper dead center of the intermediate presser are almost one. I do. When the sewing machine is stopped, depending on the rotation angle of the intermediate press cam, the slope of the cam may be urged by the spring, and a rotational force may be applied to the intermediate press cam, that is, the upper shaft. . Particularly, in the case of the sewing machine, the sewing machine is stopped when the sewing machine needle has rotated about 50 degrees from the rotation angle of the upper shaft serving as the top dead center. In this case, the intermediate presser is in the process of descending, The slope of the intermediate presser cam is pressed by a spring and stopped in a state where a rotational force is applied.

Therefore, if the resistance against the rotation of the upper shaft is not applied, even if the sewing machine stops, the sewing machine may rotate until the intermediate presser lowers, and the sewing machine may not be stopped at a predetermined sewing machine needle position. was there. In the case where the upper shaft is rotated by, for example, a belt drive method, even if a slight force such as rotating the upper shaft is applied from the outside, the upper shaft is rotated by the resistance to the rotation of the upper shaft 3 by the V belt or the like. The rotation of the upper shaft is suppressed, but when the upper shaft rotates in the direct drive system, the resistance to the rotation of the upper shaft is not so large, and the rotation force is applied to the upper shaft from the intermediate presser cam when the sewing machine stops. In such a case, there is a possibility that the position of the sewing machine needle at the time of stoppage may be lowered by slightly rotating the upper shaft.

The present invention has been made in view of the above circumstances, and can simplify the drive mechanism of the intermediate presser, and reduce the rotational force applied to the upper shaft from the drive mechanism of the intermediate presser after the sewing machine stops. It is an object of the present invention to provide a middle presser mechanism of a sewing machine which can perform the above operation.

[0011]

According to a first aspect of the present invention, there is provided an intermediate presser mechanism for a sewing machine, comprising: holding means for holding an object to be sewn; moving the holding means in a horizontal direction; Feed means for allowing a sewing needle which moves up and down by rotation of an upper shaft to be arbitrarily placed at an arbitrary position of the sewing machine, and the sewing machine moves the sewing machine horizontally with respect to the sewing needle which moves up and down. The sewing machine is provided on a sewing machine capable of forming a stitch provided by the sewing needle along an arbitrary shape by moving the sewing needle in the direction of the sewing machine. A presser is provided, and the presser is driven,
A middle press sewing operation means for moving the middle press up and down in accordance with the vertical movement of the sewing machine needle during sewing, the middle press sewing operation means including an intermediate press cam rotating integrally with the upper shaft; Intermediate presser driving means for driving the intermediate presser up and down in response to the rotation of the upper shaft as a follower of the intermediate presser cam, wherein the intermediate presser cam contacts the intermediate presser drive means. The intermediate presser can be moved between a position at which the intermediate presser can be driven up and down and a position apart from the intermediate presser driving means and at which the intermediate presser keeps holding the workpiece downward. Is a means for solving the above problem.

According to the above construction, when a normal intermediate presser which moves up and down during sewing operation is used, the intermediate presser cam is brought into contact with the intermediate presser driving means to move the intermediate presser to a position where the intermediate presser can be driven up and down. The intermediate presser cam is rotated together with the rotation of the upper shaft to drive the intermediate presser driving means serving as a follower, and the intermediate presser is moved up and down by the intermediate presser driving means. When using the intermediate presser that keeps the work to be pressed downward during the sewing operation, place the intermediate presser cam in a position that does not contact the intermediate presser driving means, and rotate the intermediate presser cam together with the upper shaft. Even if the intermediate presser driving means does not move, the intermediate presser is held in a state of being lowered.

Therefore, in this intermediate presser mechanism, an operation of moving the intermediate presser up and down during sewing using only the normal intermediate presser by simply moving the intermediate presser cam, and using an intermediate presser that does not move up and down during sewing is performed. It is possible to switch between an operation of holding the intermediate presser in a lowered state during sewing. That is, by simply adding a mechanism that can move the position of the intermediate presser cam to the mechanism that drives the normal intermediate presser up and down using the intermediate presser cam attached to the upper shaft, the two types of intermediate presser operations as described above. Can be switched, so that the configuration of the intermediate presser mechanism that can switch between two types of intermediate presser operations during sewing can be made extremely simple. By simplifying the configuration of the intermediate holding mechanism, the number of components can be reduced, the manufacturing process can be simplified, and the manufacturing cost can be reduced.

The middle holding cam has an insertion hole,
It is preferable that the upper shaft is inserted into the insertion hole, and that the intermediate presser cam is fixed to the upper shaft by a joining member such as a set screw. By releasing the fixation, the intermediate presser cam can be moved along the axial direction of the upper shaft, so that the mechanism for moving the intermediate presser can be made extremely simple. In this case, it is preferable that the position and the angle of the intermediate presser cam can be easily determined when the intermediate presser cam is brought into contact with the intermediate presser driving means. Further, when the intermediate presser cam is released from the intermediate presser driving means, it is necessary that the intermediate presser driving means can be fixed at a position where the intermediate presser is held in a lowered state. It is preferable that a member that contacts the intermediate presser driving means instead of the intermediate presser cam at a position where the intermediate presser driving means lowers the intermediate presser when the medium presser is separated from the means is provided.

According to a second aspect of the present invention, there is provided an intermediate holding mechanism for a sewing machine, comprising: holding means for holding an object to be sewn; and moving the holding means in a horizontal direction to hold the object to be sewn by the holding means. At any given position, a feed means that allows a sewing needle that moves up and down by rotation of the upper shaft to be stabbed, by moving the workpiece in the horizontal direction with respect to the sewing machine needle that moves up and down. A stitch provided by the sewing machine needle is provided on a sewing machine that can be formed along an arbitrary shape, and, in the vicinity of the sewing machine needle, includes a middle presser that presses the sewing object downward,
A drive unit for driving the intermediate presser, the drive unit driving the intermediate presser up and down, and one of moving the intermediate presser up and down by transmitting the movement from the driving unit to the intermediate presser. A presser link mechanism, wherein the link mechanism lowers the intermediate presser during sewing so as to be able to press the workpiece downward, and raises the intermediate presser while sewing is stopped to release the sewing object. Middle presser vertical movement means for allowing the attachment and detachment to the holding means, and vertically moving the middle presser in a state where the work to be sewn is pressed downward during sewing in accordance with the vertical movement of the sewing machine needle. Further, the present invention has a medium press sewing operation means for facilitating the horizontal movement of the workpiece when the sewing needle is raised.

According to the above construction, the drive unit for driving the intermediate presser has at least two of the intermediate presser vertical movement means and the intermediate presser sewing operation means, and drives one intermediate presser from the two driving devices. However, since only one intermediate presser link mechanism is used as a transmission means for transmitting the driving force from these two driving devices to the intermediate presser, it is necessary to use two The number of parts can be reduced as compared with the case where one link mechanism is used.
Therefore, according to the intermediate holding mechanism, the number of parts can be reduced, so that the manufacturing process can be labor-saving and the manufacturing cost can be reduced.

The link mechanism has a state in which the intermediate presser is largely raised so that the sewing object can be easily attached and detached while the sewing is stopped, and the intermediate presser is largely lowered so that the sewing object can be pressed at the start of sewing. During sewing, it is necessary to raise or lower the intermediate presser in a greatly lowered state so that the workpiece can move horizontally. Therefore, the link mechanism is in a state in which the intermediate presser is largely lowered by the movement transmitted from the intermediate presser vertical movement means, and does not hinder the vertical movement of the intermediate presser by the movement transmitted from the intermediate presser sewing operation means. Need to be.

According to a third aspect of the present invention, there is provided an intermediate presser mechanism for a sewing machine, comprising: holding means for holding an object to be sewn; and moving the holding means in a horizontal direction to hold the object to be sewn by the holding means. At any given position, a feed means that allows a sewing needle that moves up and down by rotation of the upper shaft to be stabbed, by moving the workpiece in the horizontal direction with respect to the sewing machine needle that moves up and down. A stitch provided by the sewing machine needle is provided on a sewing machine that can be formed along an arbitrary shape, and, in the vicinity of the sewing machine needle, includes a middle presser that presses the sewing object downward,
A middle presser supporting means for driving the middle presser, the middle presser supporting the middle presser vertically while being urged downward, and a state of being urged downward by the middle presser support means during sewing. Intermediate presser sewing operation means for transmitting rotation of the upper shaft to the intermediate presser and moving the intermediate presser up and down is provided, and the intermediate presser corresponding to rotation of the upper shaft by the intermediate presser sewing operation means is provided. The vertical movement is provided with a suspension period for temporarily suspending the vertical movement of the intermediate presser near the rotation angle of the upper shaft at a predetermined rotation angle at which the upper shaft stops when sewing is stopped. Is a means for solving the above problem.

According to the above construction, during the sewing, the intermediate presser sewing operation means transmits the rotation of the upper shaft and vertically moves to the intermediate presser in a state of being urged downward by the intermediate presser supporting means. When sewing stops and rotation of the upper shaft stops,
There is a possibility that the urging force for urging the intermediate presser downward may be transmitted to the upper shaft via the intermediate presser sewing operation means.If the intermediate presser is moved up and down by the intermediate presser sewing means, the above-mentioned pause period is provided. Otherwise, a rotational force is applied to the upper shaft that stops at a predetermined rotation angle. For example, when the upper shaft rotates by the direct drive method, a resistance that suppresses the rotation of the upper shaft is applied. Since the force is weaker than that of the belt drive system, there is a possibility that the upper shaft does not stop at a predetermined rotation angle but stops slightly.

However, in the vertical movement of the intermediate presser of the intermediate presser mechanism, the vertical movement of the intermediate presser is temporarily stopped when the rotation angle of the upper shaft becomes a predetermined rotation angle at which the upper shaft stops when sewing stops. Since a pause period is provided for pausing, the intermediate presser does not move up and down during this pause period even if the upper shaft rotates. That is, during the suspension period, the intermediate presser sewing operation means does not transmit the rotational force of the upper shaft to the intermediate presser,
The intermediate presser sewing operation means is substantially in a state of stopping transmission between the upper shaft and the intermediate presser.

Therefore, conversely, even if the upper shaft stops at the rotation angle corresponding to the pause period, the urging force for urging the intermediate presser downward is transmitted to the intermediate presser via the intermediate presser sewing operation means. There is no. Thereby, it is possible to prevent the upper shaft from rotating due to the urging force of the spring or the like for urging the intermediate presser downward. In a normal sewing machine, when the rotation angle of the upper shaft serving as the needle bar top dead center (the top dead center of the sewing machine needle) is set to 0 degree, the rotation angle at which the upper shaft stops is about 50 degrees. Therefore, the pause period is provided in the vicinity where the rotation angle of the upper shaft is approximately 50 degrees. Also, some sewing machines can be set so that the rotation of the upper shaft can be stopped at the rotation angle of the upper shaft of 0 degree, that is, the rotation angle of the upper shaft which becomes the needle bar top dead center. The pause period may be provided near the rotation angle of 0 degrees.

According to a fourth aspect of the present invention, in the intermediate presser mechanism of the sewing machine, the intermediate presser sewing operation means includes an intermediate presser cam rotating integrally with the upper shaft, and a follower of the intermediate presser cam. Intermediate presser driving means for transmitting the movement from the intermediate presser cam to the intermediate presser, wherein the vertical movement of the intermediate presser is stopped during the idle period on a cam surface of the intermediate presser cam which the intermediate presser drive means contacts. The fact that the surface to be formed is formed is a means for solving the above problem.

According to the above construction, basically, a surface is formed in which the intermediate presser driving means which follows the cam surface of the intermediate presser cam does not move. ,
For example, in the case where the intermediate presser cam is a side cam, when the rotation angle of the upper shaft reaches a predetermined stop angle, the portion of the intermediate presser cam that is in contact with the intermediate presser driving means is orthogonal to the rotation axis of the intermediate presser cam. Is to provide a flat surface. In addition, for example, when the intermediate presser cam is a plate cam, the formation of the surface means that when the rotation angle of the upper shaft reaches a predetermined stop angle, the intermediate presser cam comes into contact with the intermediate presser driving means. This is to provide an arc-shaped curved surface having a constant distance from the rotation axis.

That is, in the movement curve of the middle presser cam with respect to the rotation angle of the upper shaft of the middle presser, it is sufficient to provide a portion that is a horizontal straight line in which the middle presser does not move up and down as the above-mentioned pause period. Therefore, the rotation of the upper shaft can be prevented as described above by a very simple method of slightly changing the shape of the intermediate holding cam. That is, the rotation of the upper shaft as described above can be suppressed without increasing the number of parts and increasing the cost.

According to a fifth aspect of the present invention, there is provided an intermediate holding mechanism for a sewing machine, comprising: holding means for holding an object to be sewn; and moving the holding means in a horizontal direction to thereby hold the object to be sewn held by the holding means. At any given position, a feed means that allows a sewing needle that moves up and down by rotation of the upper shaft to be stabbed, by moving the workpiece in the horizontal direction with respect to the sewing machine needle that moves up and down. A stitch provided by the sewing machine needle is provided on a sewing machine that can be formed along an arbitrary shape, and, in the vicinity of the sewing machine needle, includes a middle presser that presses the sewing object downward,
A middle presser supporting means for driving the middle presser, the middle presser supporting the middle presser vertically while being urged downward, and a state of being urged downward by the middle presser support means during sewing. The intermediate presser transmits the rotation of the upper shaft to the intermediate presser, and is provided with an intermediate presser sewing operation means for vertically moving the intermediate presser.
A predetermined rotation angle at which the upper shaft stops at the time of sewing stop, or a rotation angle of the upper shaft which is the upper dead center of the sewing machine needle, and a predetermined rotation at which the upper shaft stops. The angle is set to be equal to or less than the angle.

According to the above arrangement, the moment when the intermediate presser reaches the top dead center is when the movement of the intermediate presser changes from ascending to descending, and the vertical movement of the intermediate presser is momentarily stopped. Therefore, when the intermediate presser reaches the top dead center, the rotational force of the upper shaft is not transmitted by the intermediate presser sewing operation means as the raising or lowering of the intermediate presser. Also,
When moving the intermediate presser up and down, it is assumed that the intermediate presser rises at a constant speed until it reaches the top dead center of the intermediate presser, stops at the top dead center of the intermediate presser, and descends at the same speed as when it was raised. In this case, sudden stop and sudden acceleration are almost impossible. In practice, it is necessary to make the vertical movement of the intermediate presser near the top dead center of the intermediate presser gentle.

That is, at the top dead center of the center presser, the transmission between the upper shaft and the center presser becomes almost zero, and before and after the top dead center of the center presser, the transmission between the upper shaft and the center presser is reduced. Transmission is low. Therefore, at the top dead center of the intermediate presser and in the vicinity thereof, the transmission between the upper shaft and the intermediate presser is substantially not performed or only slightly performed by the intermediate presser sewing operation means. If the rotation angle of the upper shaft, which is the top dead center of the presser foot, is set to be approximately equal to the rotation angle at which the upper shaft stops, the rotation force that exceeds the resistance of the drive system (direct drive) applied to the upper shaft will increase. It can be prevented from hitting the shaft.

Further, depending on the sewing machine, not only the rotation of the upper shaft is stopped when the rotation angle of the upper shaft is about 50 degrees as described above, but also the rotation angle of the upper shaft is changed by changing the setting. The upper shaft can be stopped even when the rod reaches the top dead center.However, by setting the top dead center of the center presser between the stop rotation angles of the above two upper shafts, The rotation angle of the upper shaft, which becomes the top dead center, and the two rotation stop angles and the intervals are closer to each other, and the rotation force applied to the upper shaft from the intermediate presser sewing operation means at the two rotation stop angles is made as small as possible. Thus, even if a rotational force is applied to the upper shaft, the magnitude of the rotational force can be prevented from becoming larger than the magnitude of the resistance to the rotation applied to the upper shaft from a drive system or the like.

That is, it is possible to prevent the upper shaft from rotating due to the force flowing backward from the intermediate presser sewing operation means.
In the case where the intermediate presser is driven by the intermediate presser cam as described in claim 4 above, the intermediate presser can be moved to the upper shaft only by changing the mounting angle of the intermediate presser cam to the upper shaft. The rotation force can be stopped from the sewing operation means,
The upper shaft can be stopped at a precise position with little cost and effort.

[0030]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows the appearance of the sewing machine 1 of this example, and FIG.
3 shows the intermediate presser mechanism 10 in an expanded state, and FIGS.
7 shows a state in which only the intermediate presser mechanism 10 is taken out of the sewing machine 1, FIG. 7 shows a mounting structure of the intermediate presser cam 31 to the upper shaft 3 of the sewing machine 1, and FIG. 12 shows the motion curve of FIG. 12, and FIG.
The rotational force applied from 0 to the upper shaft 3 of the sewing machine 1 is illustrated in correspondence with the motion curve.

As shown in FIG. 1, the intermediate presser mechanism 10 of the present invention
The sewing machine 1 includes a holding mechanism 6 for sandwiching and holding a sewing object between the lower plate 4 and the outer frame 5 of the presser foot.
And a feed mechanism (not shown) for moving the
By moving the workpiece in the horizontal direction with respect to the sewing needle 7 in a state where the position in the horizontal plane is fixed, a predetermined range (for example, the inside of the lower plate 4 and the presser foot outer frame 5, or It is possible to attach a stitch to an arbitrary position within the movable range of the holding mechanism 6 with respect to the sewing needle 7 by the feed mechanism). That is, sewing machine 1
Is a cycle sewing machine capable of forming seams corresponding to various shapes.

In the sewing machine 1, the holding mechanism 6 holds the outside of a portion where sewing is performed by the lower plate 4 and the outer frame 5 of the presser foot. Is not in a state where the cloth presser outer frame 5 of the holding mechanism 6 presses the vertical movement position.
The intermediate presser 12 presses a portion of the sewing machine 7 on which the sewing machine needle 7 moves up and down from above. That is, in the sewing machine 1, the work to be sewn is pressed downward by the cloth presser outer frame 5 and the intermediate presser 12.

Here, the intermediate presser mechanism 10 of the sewing machine 1 in this example will be described. As shown in FIGS. 2 to 6, the intermediate presser mechanism 10 has the intermediate presser 12 that presses a portion of the sewing machine 7 where the sewing needle 7 moves up and down as described above, and drives the intermediate presser 12. It is. The intermediate presser mechanism 10 includes the intermediate presser 12 and supports the intermediate presser 12 so as to be able to move up and down. The intermediate presser support mechanism 11 can lower the intermediate presser 12 during sewing on the sewing machine 1 and press the workpiece. A middle presser vertical moving section 20 which raises the intermediate presser 12 while the sewing operation is stopped to enable setting or replacement of the sewing object, and presses the workpiece by the intermediate presser vertical moving section 20. A middle presser sewing operation section 30 that moves the intermediate presser 12 in a state capable of performing up and down in small increments in accordance with the operation of the sewing needle 7 during sewing, and a middle presser vertical movement section 20 and a middle presser sewing operation section. And a middle presser link 40 for transmitting a movement for vertically moving the middle presser 12 from 30 to the middle presser support portion 11.

The intermediate presser support portion 11 includes an intermediate presser 12 for holding the work to be sewn as described above, an intermediate presser bar 13 joined to the upper portion of the intermediate presser 12, and an upper joint to the upper portion of the intermediate presser bar 13. The cylindrical presser bar metal 14, the presser guide bar 15 inserted inside the presser bar metal 14, and the outer peripheral portion of the presser bar 13, and the presser link 40 The intermediate presser bar holding member 16 and the intermediate presser guide rod 1
5, an intermediate presser adjusting screw 17 and an intermediate presser adjusting nut 18, which are connected to the upper end of the presser 5 and are attached to the machine frame 2 and adjust the vertical position of the intermediate presser guide rod 15.
2 is provided with a middle presser spring 19 (shown in FIG. 3) for urging the lower part 2.

The middle presser 12 is formed in a ring shape with a lower surface of a lower end portion for pressing a workpiece to be sewn, and the sewing machine needle 7 penetrates the lower end portion to move up and down. I have. That is, the intermediate presser 12 is
The sewing object is pressed around the periphery of the object. As shown in FIG. 3, the middle presser 12 has an upper part attached to the middle presser rod 13 by screws 12a and washers 12b, and the finger guard 12c is fixed together with the middle presser 12 by these screws 12a and washers 12b. It is attached to the presser bar 13. The screw holes for the screws 12a of the intermediate presser 12 are vertically long holes, so that the vertical position of the intermediate presser 12 can be finely adjusted.

The middle presser bar 13 joins the middle presser 12. The middle presser bar metal 14 is formed in a tubular shape, and the middle presser bar 13 is inserted therein.
2 can be moved up and down.

The middle presser guide rod 15 is provided with a middle presser spring 19.
And supports the middle presser spring 19. The intermediate presser bar holder 16 has a state in which the intermediate presser bar 13 penetrates and is fixed to the intermediate presser bar 13 by a set screw 16a. Further, the intermediate presser bar holding plate 16d is attached to the intermediate presser bar holding plate 16 with screws 16b and washers 16c.

The inner holding bar holding plate 16d is in contact with the lower surface of the inner holding bar holding plate 16d so that the inner holding link 40 is locked. The intermediate presser 12 and the intermediate presser bar 13 are prevented from dropping downward due to gravity and the urging force of the intermediate presser spring 19, and the intermediate presser bar holder 16 is pressed upward by the intermediate presser link 40. , The intermediate presser 12 and the intermediate presser bar 13 can be raised upward.

That is, the movement is transmitted to the intermediate presser bar holder 16 from the intermediate presser link 40, and the intermediate presser 12 can be driven up and down. The adjusting screw 17 and the intermediate presser adjusting nut 18 adjust the urging force of the intermediate presser spring 19 to adjust the pressing force of the intermediate presser 12 against the workpiece. The intermediate presser spring 19 is, for example, a coil spring that presses the intermediate presser 12 downward, and generates a pressing force of the intermediate presser 12 against a workpiece.

As shown in FIGS. 2 to 6, the middle presser vertical moving unit 20 includes a middle presser lifting mechanism 23 including a middle presser link 21 and a middle presser lifting spring 22, a solenoid 24 and three middle presser lowerers. And a middle presser lowering mechanism 28 composed of links 25, 26 and 27. The above-mentioned intermediate presser lifting mechanism 23 applies the tension of the intermediate presser spring 19 to the intermediate presser lifting link 21 whose tip is connected to the intermediate presser link 40 by the intermediate presser lifting spring 22 (coil spring) connected to its rear end. This pulls the sewing machine 1 rearward, thereby holding the intermediate presser link 40 at a position where the intermediate presser 12 is raised.

The middle press-up link 21 is a thin linear rod, and a portion connected to the middle press-link 40 at the end thereof is bent into a U-shape. When the intermediate presser lifting link 21 is urged rearward by the intermediate presser lifting spring 22 and moves rearward, the distal end of the intermediate presser lifting link 21 is attached to one end (upper end) of the intermediate presser link 40. The intermediate presser link 40 is adapted to rotate so that one end thereof moves backward.
When is moved forward by the intermediate presser lowering mechanism 28 as described later, the distal end of the intermediate presser lifting link 21 does not engage with one end of the intermediate presser link 40.

Accordingly, when the intermediate presser link 21 is moved forward, the movement of the intermediate presser link 21 causes
Although one end of the intermediate presser link 40 cannot be moved forward, in this case, the intermediate presser link 40 is moved so that one end of the intermediate presser link 40 moves forward by the urging force of the intermediate presser spring 19. 40 rotates. And middle presser 1
The downward movement of 2 is restricted by the intermediate presser rod 33 described later, so that the rotation of the intermediate presser link 40 is stopped.

In this state, the U-shaped distal end of the intermediate press-up link 21 does not restrict the one end of the intermediate press link 40 from moving backward within a certain range. , The intermediate presser sewing operation section 3
With 0, it is possible to move one end of the intermediate presser link 40 backward or back. That is, the connecting portion between the intermediate presser link 40 and the intermediate presser lifting link 21 is in a state substantially the same as that of the connection by the elongated hole and the pin, that is, a state in which a large play is provided. The intermediate presser link 40 can be rotated without affecting the intermediate presser lifting link 21. As shown in FIG. 3, the intermediate presser lifting link 21 and the distal end of the intermediate presser lifting spring 22 are connected together with the intermediate presser lowering link 27 by a pin 27a of the intermediate presser lowering link 27 and a retaining ring 27b. . The rear end of the intermediate presser lifting spring 22 is connected to the machine frame 2 with screws 22a,
It is hung and fixed on a spring hook 22b fixed by 2a.

The intermediate presser lowering mechanism 28 includes a plunger 24c of the solenoid 24 and the intermediate presser lifting link 21.
And three middle presser-down links 25, 26, 27
When the solenoid 24 is turned on and the plunger 24c is retracted, the intermediate press-up link 21 is biased by the intermediate press-up link 22 via the three intermediate press-down links 25, 26 and 27. It pushes forward in opposition. Then, by pushing the intermediate presser lifting link 21 forward, the holding of the intermediate presser link 40 at the position where the intermediate presser 12 is raised is released, and the intermediate presser 12 is pressed by the urging force of the intermediate presser spring 19. It is designed to go down.

The solenoid 24 is fixed to the machine frame 2 by screws 24b via a mounting plate 24a. The middle presser link 25 is formed in a substantially rectangular shape, and its center is rotatably supported by a fulcrum shaft 25b fixed to the machine frame 2 by a set screw 25a. The lower end of the middle presser link 25 is connected to the plunger 24c of the solenoid 24 by a connection pin 24b and pine needle pins 24e, 24e.

The upper end of the intermediate presser link 25 is
It is connected to the intermediate presser link 26 by the step screw 25c. The middle holding down link 26 is formed in a substantially rectangular shape, and the lower end portion thereof has a middle holding down link 26.
, And the upper end thereof is connected to a middle holding down link 27 by a step screw 26a. The intermediate presser link 27 is formed in a substantially L-shape when viewed from the side, and a fulcrum shaft (not shown) whose central portion is fixed to the machine frame 2.
Is rotatably supported. In addition, middle presser link 2
Reference numeral 7 has a rear end connected to the intermediate presser link 26 and a distal end connected to the intermediate presser link 21 and the intermediate presser spring 22 as described above.

When the solenoid 24 is off, the pressing force of the middle presser lifting spring 22 causes the middle presser lowering link 27 to rotate clockwise to move the middle presser lifting link 21 connected to the middle presser lowering link 27 backward. Will be moved.

Then, as shown in FIG.
4 is in the ON state, the plunger 24c retreats rearward, the intermediate presser link 25 rotates counterclockwise to push up the intermediate presser link 26, and the intermediate presser lower link 26 to the intermediate presser link. 27 will be pushed upward. The intermediate presser lowering link 27 rotates counterclockwise in the drawing, and its front end moves forward, and the intermediate presser lifting link 21 connected to the intermediate presser lowering link 27 is attached to the intermediate presser lifting spring 22. They will move forward against the power. Thereby, the intermediate presser link 40 is in a state where the intermediate presser 12 is pulled up.

The intermediate presser sewing operation section 30 is shown in FIGS.
The middle presser cam 3 fixed to the upper shaft 3 is used for slightly moving the intermediate presser 12 up and down during sewing.
1 and a middle presser driving arm 3 which is a follower of the middle presser cam 31
2, an intermediate presser rod 33 that transmits the movement of the intermediate presser drive arm 32 to the intermediate presser link 40, a cam thrust collar 34 that determines the position of the intermediate presser cam 31, and stops the intermediate presser sewing operation as described later. And a receiving portion 35 for receiving the intermediate presser driving arm 32 at this time.

As shown in FIG. 7, the intermediate pressing cam 31 includes a cylindrical portion 31a, a cam portion 31b provided behind the cylindrical portion 31a, and a positioning pin 31c. The upper shaft 3 is in a penetrating state, and is fixed to the upper shaft 3 by set screws 31d, 31d. The middle presser cam 31 has a cam portion 31b.
Is a side cam serving as a cam, and when the upper shaft 3 rotates to move the sewing machine needle 7 up and down, a middle presser driving arm 32 serving as a follower is formed on the front side surface of the cam portion 31b. Driven along the curved surface.

Further, the intermediate presser cam 31 is provided with a set screw 31.
d and 31d can be loosened and moved rearward along the upper axis, whereby the engagement between the intermediate press drive arm 32 and the intermediate press cam 31 can be released.
The front and rear positions of the intermediate presser cam 31 are regulated by a cam thrust collar 34 fixed to the upper shaft 3. After the intermediate presser cam 31 is retracted as described above, the intermediate presser cam 31 When the 31 is returned to the original position, the positioning can be easily performed by bringing the front surface of the cylindrical portion 31a of the intermediate pressing cam 31 into contact with the cam thrust collar 34.

The cylindrical portion 31a is formed between the cam thrust collar 34 and the cam portion 31b so that the cam thrust collar 34 disposed in front of the intermediate presser cam 31 does not hinder the movement of the intermediate presser drive arm 32. They are designed to be far apart.
The positioning pin 31c is provided so as to extend forward from the front surface of the cylindrical portion 31a.
The angle of the intermediate presser cam 31 is determined by being inserted into the hole 34a provided in the base 4.

That is, the intermediate presser 12 operates in conjunction with the sewing machine needle 7, but when the intermediate presser cam 31 is retracted as described above, the intermediate presser cam 31 may rotate slightly. Even if the front and rear positions of the intermediate presser cam 31 are adjusted as described above, the operation of the intermediate presser 12 and the sewing machine needle 7 can be performed.
However, as described above, the positioning pin 31c of the intermediate pressing cam 31 and the hole 34a of the thrust collar 34 for the cam cause the timing of the intermediate pressing cam 31 to shift.
Can be easily determined even if the intermediate presser cam 31 is moved in some cases.
And the operation timing of the sewing machine needle 7 can be adjusted. The cam thrust collar 34 is formed in a ring shape and is fixed to the upper shaft 3 by set screws 34b, 34b in a state where the upper shaft is penetrated. After the angle is fixed and fixed, it is basically not moved or removed.

As shown in FIG. 3, the center press drive arm 32 has a central portion rotatably supported by the machine frame 2 by a stepped screw 32a. A roller shaft 32b and a roller shaft nut 3 are provided on the upper end side of the intermediate presser drive arm 32.
The roller 32d is rotatably attached by 2c. A receiving portion 3 fixed to the machine frame 2 is provided at the upper end of the intermediate presser drive arm 32 when the intermediate presser cam 31 is retracted.
5 is provided.

An elongated hole 32f is formed at the lower end of the intermediate presser driving arm 32, and the rear end of the intermediate presser rod 33 is formed by a step screw 33a and a nut 33b inserted into the elongated hole 32f. Are rotatably connected at any position.
The middle presser rod 33 has its rear end connected to the lower end of the middle presser drive arm 32 as described above, and has a long slot 33c formed in the front end thereof at the front and rear. The rod 33 is rotatably and slidably connected to the intermediate holding link 40.

The intermediate holding link 40 has a substantially L-shape, and a fulcrum shaft 42 fixed to the machine frame 2 by a set screw 41.
And a thrust collar 43 externally mounted on the fulcrum shaft 42, and is rotatably supported by the machine frame 2. The rear end (upper end) of the intermediate presser link 40 is connected to the front ends of the intermediate presser rod 33 and the intermediate presser lifting link 21 by an intermediate presser link pin 44 and an intermediate presser link nut 45. In FIG. 2 and the like, basically, the intermediate presser mechanism 1
Although only the reference numeral 0 and members related thereto are illustrated, FIG. 2 illustrates a mechanism for moving the holding mechanism 6 and the outer frame 5 of the holding mechanism up and down, and the like.

Next, the intermediate presser mechanism 1 in the sewing machine 1
The operation and action of 0 will be described. First, while the sewing machine 1 is stopped, as shown in FIG. 4, the solenoid 24 of the intermediate presser lowering mechanism 28 of the intermediate presser vertical moving unit 20 is turned off, and the intermediate presser The link 27 is rotated clockwise, and at this time, the plunger 24c is extended via the intermediate holding down links 26 and 27. Then, the intermediate presser lifting link 21 connected to the front end of the intermediate presser lowering link 27 is urged rearward by the intermediate presser lifting spring 22 and is retracted by the intermediate presser lowering link 27.

When the intermediate presser link 21 is retracted, the upper end of the intermediate presser link 40 is retracted, and the front end of the intermediate presser link 40 is elevated. As a result, the intermediate presser bar holder 16 of the intermediate presser supporting portion 11 in a state where the front end portion of the intermediate presser link 40 abuts on the lower surface together with the intermediate presser bar 13 and the intermediate presser 12 and the intermediate presser spring 19 (see FIG. Has risen against the urging force of. That is, the intermediate presser 12 is raised and the sewing object is not pressed, that is, the sewing object can be attached to and detached from the holding mechanism 6.

In this case, the intermediate presser sewing operation section 30
In the above, the intermediate presser rod 33 is not pulled forward by the intermediate presser link 40, and the intermediate presser rod 3
Reference numeral 3 denotes a substantially free state, and the lower end of the intermediate presser drive arm 32 is also substantially free without being pulled forward by the intermediate presser rod 33.

In the middle presser sewing operation section 30,
Since the portion of the middle presser rod 33 to which the middle presser link 40 is connected is a long hole 33c, in the state shown in FIG. The presser link 40 and the intermediate presser 12 are not affected.

Next, when sewing is started, as shown in FIG. 5, the solenoid 24 is turned on, and the plunger 24c is retracted.
6, the rear end of the push-down link 27 rotates so as to ascend, so that the front end of the push-down link 27 moves forward against the biasing force of the middle press-up spring 22 and moves the push-up link 21 forward. Let it. Then, by moving the distal end of the push-up link 21 in a state where the upper end of the intermediate presser link 40 is being pulled forward, the state in which the upper end of the intermediate presser link 40 is held rearward is released.

At this time, the presser bar 13, the presser 12, and the presser bar holder 16 are moved downward by the urging force of the presser spring 19, whereby the front end of the presser link 40 is pushed down. Then, the upper end of the middle presser link 40 moves forward. As a result, the intermediate presser 12 is lowered, and a state in which the workpiece is pressed can be obtained. On the other hand, in the intermediate presser sewing operation section 30, as shown in FIG. 5, when the intermediate presser link 40 is rotated by the urging force of the intermediate presser spring 19 to move the front end thereof downward,
The upper end of the intermediate presser link 40 moves forward.

Then, the intermediate presser rod 33 connected to the upper end of the intermediate presser link 40 moves forward, and the lower end of the intermediate presser drive arm 32 to which the intermediate presser rod 33 is connected is pulled forward. The intermediate presser drive arm 32 rotates,
The roller 32d at the upper end moves rearward, and
1 is in contact with the front side surface. And, the intermediate presser drive arm 32
Roller 32d abuts on the intermediate presser cam 31,
The rotation for moving the upper end of the intermediate presser drive arm 32 further rearward, that is, the rotation for moving the lower end further forward, is restricted.

As a result, the forward movement of the intermediate presser rod 33 is restricted, and the rotation of the upper end of the intermediate presser link 40 is moved forward, that is, the intermediate presser bar holder 16 and the intermediate presser 12 are moved by the intermediate presser spring. Is pressed downward, and rotation by which the front end of the intermediate holding link 40 is moved downward by the intermediate holding rod holding member 16 is regulated. As a result, the lowering of the intermediate presser 12 stops.

When the sewing of the sewing machine 1 is started, the upper shaft 3 for vertically moving the sewing needle 7 is rotated. Accordingly, the intermediate presser cam 31 which is a side cam fixed to the upper shaft 3 also rotates, and the upper end of the presser drive arm 32 in which the roller 32 d contacts the side surface of the intermediate presser cam 31 is moved to the side of the intermediate presser cam 31. It will move back and forth in response to the undulation. Thus, the intermediate presser rod 33 connected to the intermediate presser drive arm 32 moves back and forth. By adjusting the continuous position of the intermediate presser rod 33 with respect to the intermediate presser drive arm within the elongated hole 32f of the intermediate presser drive arm 32, the amount of forward and backward movement of the intermediate presser rod 33 can be changed. Further, the upper end of the intermediate presser link 40 connected to the intermediate presser rod 33 moves back and forth, whereby the intermediate presser link 40 rotates back and forth, and the intermediate presser link 40
The front end moves up and down.

The vertical movement of the front end of the intermediate presser link 40 moves the intermediate presser bar holder 16 up and down, and the intermediate presser 12 joined to the intermediate presser bar holder 16 via the intermediate presser bar 13 moves up and down. Will be. That is, the intermediate presser 12 moves up and down corresponding to the sewing needle 7 that moves up and down by the rotation of the upper shaft 3. In this case, the intermediate presser vertical moving part 2
The upper end of the intermediate presser link 40 to which the front end of the intermediate presser lifting link 21 is connected moves back and forth, but the intermediate presser lifting link 21 has a large play at its U-shaped tip portion. Since the intermediate presser link 40 is connected to the intermediate presser link 40 while being held, it does not prevent the intermediate presser link 40 from moving back and forth within a small angle range by the intermediate presser sewing operation unit 30.

When the sewing is stopped,
When the solenoid 24 of the intermediate presser vertical moving unit 20 is turned off,
As shown in FIG. 4, the intermediate press-up link 21 held on the front side against the urging force of the intermediate press-up spring 22 is pulled rearward by the intermediate press-up spring 22. As a result, the upper end of the intermediate presser link 40 connected to the intermediate presser lifting link 21 moves rearward and the intermediate presser link 4
The front end portion of the intermediate presser 0 moves upward, the intermediate presser bar holding 16 is pushed up by the intermediate presser link 40, and the intermediate presser 12 rises.

The lowering distance of the intermediate presser 12 at the start of sewing by the intermediate presser vertical moving section 20 and the intermediate presser 12 at the time of sewing stop
Is, for example, about 20 mm, and the vertical movement distance of the intermediate presser 12 during sewing by the intermediate presser sewing operation unit 30 is, for example, about 4 mm. Further, the lowering of the intermediate presser 12 by the intermediate presser vertical moving unit 20 is not performed only at the time of starting sewing, for example, when the sewing needle 7 is stopped.
When both the presser 12 and the intermediate presser 12 are raised, the threading to the sewing machine needle 7 is hindered by the tip of the intermediate presser 12, so that the solenoid 24 is turned on at the time of threading as well as when the sewing is started. It is possible to lower the presser foot.

Next, a case will be described in which the intermediate presser 12 (actually, having a shape different from that of the intermediate presser 12 in the drawing) which does not need to be moved up and down during sewing is attached to the intermediate presser support portion 11. In this case, as shown in FIG. 6, the intermediate presser cam 31 is moved backward along the upper shaft 3 in advance. Then, the lowering of the intermediate presser 12 at the start of sewing is performed in the same manner as described above.

At the time of starting sewing, the intermediate presser link 40 is rotated forward by the intermediate presser vertical moving section 20 and its front end is moved downward, whereby the intermediate presser 1 is moved.
In the case where 2 is lowered, the upper end of the intermediate presser link 40 moves forward, whereby the intermediate presser rod 33 moves forward, and the lower end of the intermediate presser drive arm 32 connected to the intermediate presser rod 33 moves. The intermediate presser drive arm 32 rotates so as to move forward.

As a result, the upper end of the intermediate presser drive arm 32 moves backward. At this time, since the intermediate presser cam 31 is in a retracted state, the intermediate presser drive arm 3
Before the roller 32d at the upper end of the roller 2 comes into contact with the intermediate presser cam 31, the contact portion 32e at the upper end of the intermediate presser drive arm 32 comes into contact with the receiving portion 35 fixed to the machine frame. Thereby, the further rotation of the intermediate presser drive arm 32 to the rear side is restricted, so that the forward movement of the intermediate presser rod 33 and the forward rotation of the intermediate presser link 40 are restricted,
Finally, further downward movement of the intermediate presser 12 is restricted.

Accordingly, the state in which the intermediate presser 12 is lowered to the predetermined position is maintained. That is, the roller 32d
And the intermediate presser cam 31 do not come into contact with each other.
The intermediate presser drive arm 32 does not drive even if rotates, and during sewing,
The intermediate presser 12 is held in a state of being lowered to a predetermined position.
In such a state, the upward movement of the intermediate presser 12 is restricted by the downward urging force of the intermediate presser spring 19, and the force against the urging force of the intermediate presser spring 12 is reduced. When it is applied from the outside, the intermediate presser 12 can be raised.

When the sewing is stopped, the intermediate presser 12 is raised as in the case described above. When the intermediate presser 12 that does not require vertical movement during sewing as described above is replaced with the intermediate presser 12 that requires normal vertical movement, the intermediate presser cam 3
1 is moved forward to be fixed to the upper shaft 3. In this case, as shown in FIG.
The front end surface of the cam 1a is brought into contact with the cam thrust collar 34, and at this time, the pin 31c of the middle press cam 31 is inserted into the hole 34a of the cam thrust collar 34, so that the middle press cam 31 can be easily restored. At the original angle.

That is, even if the fixing of the intermediate presser cam 31 to the upper shaft 3 is released according to the situation, it can be easily fixed at the original position at the original angle. That is, when the position of the intermediate presser cam 31 is shifted or the angle is shifted, the vertical position of the intermediate presser 12 is shifted, or the timing of the operation of the intermediate presser 12 and the sewing machine needle 7 is shifted. In this example, since the intermediate presser cam 31 can be easily fixed to the upper shaft 3 at a normal position and angle,
The above problem does not occur.

Next, the operation during sewing of the intermediate presser 12 by the intermediate presser cam 31 will be described. FIG. 8 shows an example of a conventional motion curve of the intermediate presser 12, an example of a motion curve in which the cam curve is changed to provide a pause period in this example, and a motion curve in which the movement of the cam curve is shifted in this example. Is shown. FIG. 9 shows the rotational force applied to the upper shaft 3 by the force pressing the roller 32 d of the intermediate presser drive arm 32 against the intermediate presser cam 31 when the intermediate presser 12 is at each position shown in the above-mentioned movement curve. It is shown.

Note that the force for rotating the upper shaft 3 is the roller 3
This is due to the inclination angle of the cam surface of the portion where 2d is in contact. On the surface perpendicular to the axial direction of the upper shaft 3, the rotational force is substantially zero, and when the upper shaft 3 is rotated in the normal rotation direction, When the roller 32d is in contact with the cam surface inclined so as to retreat along the axial direction, a force in the normal rotation direction is applied to the upper shaft 3 to rotate the upper shaft 3 in the normal rotation direction. In this case, when the roller 32d is in contact with the cam surface inclined so as to advance in the axial direction, a force in the reverse direction is applied to the upper shaft 3.

Further, the larger the angle of inclination with respect to the plane perpendicular to the upper shaft 3, the greater the rotational force applied to the upper shaft 3. First, the motion curve of the conventional intermediate presser 12 will be described. In the conventional example, the upper dead center of the needle bar and the lower dead center of the needle bar (the angle of the upper shaft at which the vertically moving sewing needle 7 is highest and the angle of the upper shaft at which it is lowest) are basically the top dead center of the intermediate presser 12. The center presser 12 is moved up and down at substantially the same timing as the vertical movement of the sewing machine needle 7.

In the sewing machine, the sewing machine is basically stopped in a state where the sewing needle 7 is raised to a certain extent so that the work at the time of stopping the sewing machine such as replacement of a sewing object does not become difficult. Generally, when the sewing machine stops sewing, the rotation of the upper shaft 3 is stopped when the sewing machine needle 7 is slightly lowered from the top dead center. Then, the angle of the upper shaft 3 at which the needle bar supporting the sewing machine needle 7 becomes the top dead center is set to 0.
In the case of degrees, the angle of the upper shaft 3 at which the sewing machine needle 7 stops is generally set to around 50 degrees. For example, when a thick material is used as the sewing material, it is preferable that the needle is raised as much as possible when replacing the sewing material. Can be set to stop the sewing machine 1
It is also possible to stop at the needle bar top dead center.

The position of the intermediate presser 12 at the sewing machine stop angle of 50 degrees is determined as shown in FIG. 8 when the vertical movement timing of the conventional intermediate presser 12 and the vertical movement timing of the sewing needle 7 are the same. , A position slightly lowered from the top dead center. In this case, since the roller 32d of the intermediate presser driving arm 32 is in contact with the slope of the intermediate presser cam 31,
As shown in FIG. 9, when the roller 32 d is pressed against the intermediate pressing cam 31, a force in the normal rotation direction is applied to the upper shaft 3.

That is, the biasing force of the intermediate presser spring 19 is applied to the intermediate presser bar holder 16, the intermediate presser link 40, and the intermediate presser rod 3.
When the roller 32 d of the intermediate presser drive arm 32 is pressed against the intermediate presser cam 31 via the intermediate presser 3, a forward rotation force is applied to the upper shaft 3 based on the urging force of the intermediate presser spring 19. In addition, in the conventional sewing machine, the upper shaft 3 is generally driven by a belt, and in a state where a resistance force is applied so as to suppress the rotation of the upper shaft 3 in a stopped state, The upper shaft 3 is not rotated by the biasing force of the spring 19.

However, in this example of the sewing machine 1,
The drive of the upper shaft 3 is, for example, a direct drive for preventing rotation loss and improving responsiveness, and a load for suppressing rotation applied to the upper shaft 3 when the sewing machine is stopped is smaller than that of a belt drive or the like. As a result, the upper shaft 3 may rotate slightly even with the force of the biasing force of the middle presser spring 19, and the stop position of the sewing machine needle 7 may change. Therefore, when the cam curve of this example is changed to provide a pause period, the rotation angle of the upper shaft 3 on the cam surface of the intermediate presser cam 31 is about 0 degree (needle bar top dead center) and about 50 degrees. With respect to (the sewing machine stop angle), a plane perpendicular to the upper shaft 3 is formed to a certain extent in a portion where the roller 32d contacts.

Accordingly, the case where the intermediate presser 12 is near the top dead center (same as the needle bar top dead center) as in the case where a pause period indicated by the chain line in FIG. Angle is 5
The vertical movement of the intermediate presser 12 temporarily stops (pauses) when it is near 0 degrees. That is, a suspension period for the vertical movement of the intermediate presser 12 is provided.
When the rotation angle of the upper shaft 3 is around 0 degree and around 50 degrees, the roller 32d of the intermediate presser driving arm 32 is
As shown in FIG. 9, by contacting a plane perpendicular to the upper shaft 3 formed on the cam surface of the first cam surface 1, the upper and lower ends of the upper shaft 3 (around 0 degree) and the sewing machine stop angle (50 The rotation force to the upper shaft 3 generated by the intermediate presser sewing operation unit 30 before and after (approximately degrees) is zero.

If the angle at which the sewing machine is actually stopped is fixed to an angle at which the upper shaft 3 is rotated by about 50 degrees from the needle bar top dead center, for example, the upper shaft which becomes the needle bar top dead center is set. It is not necessary to provide the above-mentioned plane at the position of the intermediate presser cam 31 corresponding to the rotation angle (0 degree) of No. 3. When the needle bar top dead center and the top dead center of the center presser 12 coincide with each other, the rotational force from the center presser sewing operation unit 30 to the upper shaft 3 becomes substantially zero at the needle bar top dead center. At the same time, since the rotational force in the vicinity of the needle bar top dead center is also low, even when the rotation of the upper shaft 3 is stopped at the needle bar top dead center, the rotation angle (0 degree) of the upper shaft 3 necessarily serving as the needle bar top dead center It is not necessary to provide the above-mentioned plane at the position of the intermediate presser cam 31 corresponding to the above.

On the other hand, when the rotation angle of the upper shaft 3 for actually stopping the sewing machine is fixed to, for example, the rotation angle at which the needle bar becomes the top dead center, the rotation angle corresponds to the above-mentioned vicinity of 50 degrees. It is not necessary to provide the above-mentioned plane at the position of the intermediate presser cam 31, and it is sufficient to provide the above-mentioned plane at a position corresponding to the needle bar top dead center of the intermediate presser cam 31. By providing a flat surface at a position corresponding to the position where the upper shaft 3 of the intermediate presser cam 31 stops as described above, it is possible to prevent a rotational force from being applied to the upper shaft 3 from the intermediate presser sewing operation unit 30. it can.

When the phase of the cam curve is shifted, the phase is shifted basically without changing the shape of the movement curve of the intermediate presser 12 by the intermediate presser cam 31.
That is, the rotation angle of the upper shaft 3 at which the center presser 12 becomes the top dead center is not set to the same 0 degree as that of the needle bar, but is made larger than the rotation angle at which the needle bar top dead center is set. Is closer to the sewing machine stop angle (around 50 degrees).

As shown in FIG. 9, the rotational force applied to the upper shaft 3 decreases near the top dead center of the intermediate presser, and becomes substantially zero at the top dead center. Therefore, if the sewing machine stop angle of the upper shaft 3 and the rotation angle of the upper shaft 3 at which the center presser 12 becomes the top dead center are matched, a rotational force is applied from the intermediate presser sewing operation unit 30 to the upper shaft 3 when the sewing machine stops. Can be almost completely prevented.

However, in this example of sewing machine 1,
By changing the setting, the rotation angle of the upper shaft when the sewing machine stops can correspond to the needle bar top dead center (0 degree). Then, as described above, when the top dead center of the intermediate presser 12 is delayed with respect to the needle bar top dead center, when the rotation of the upper shaft 3 is stopped at the needle bar top dead center, The force in the reverse direction comes to act. Therefore, when the phase of the cam curve is shifted, the needle shaft of the upper shaft 3 is turned up (0 degree) and the normal stop angle of the sewing machine (5 degrees).
The upper dead point of the middle presser 12 is arranged at a substantially middle angle between the center presser 12 and the vicinity (for example, about 0 degree).

That is, the intermediate presser cam 31 is arranged so as to be rotated with respect to the upper shaft 3 so as to shift the phase by about 25 degrees from the normal angle. In this case, as shown in FIG. 9, the rotational force in the reverse rotation direction and the rotation force in the forward rotation direction at the upper shaft top dead center angle and the sewing machine stop angle at the upper shaft 3, respectively, as shown in FIG. , The rotational force acting on the upper shaft 3 is smaller than the rotational force acting on the upper shaft 3 at the conventional sewing machine stop angle.

When the upper shaft 3 is of the direct drive type, the resistance to the rotation of the upper shaft 3 is smaller than that of the belt drive type, but is not completely zero. If the rotational force applied to the shaft 3 is reduced to some extent, the rotation of the upper shaft 3 can be suppressed. Therefore, as described above, when the phase of the vertical movement of the intermediate presser 12 by the intermediate presser cam 31 is shifted from the timing of the vertical movement of the sewing machine needle 7, the upper shaft 3 stops at a predetermined angle. In addition, it is possible to prevent the upper shaft 3 from being applied with a rotational force that may rotate the upper shaft 3. If shifting the angle of the bottom dead center of the middle presser becomes a problem, it is also possible to use a cam having a cam curve in which only the top dead center of the middle presser is shifted.

The middle pressing cam 31 and the cam thrust collar 34 are not limited to those described above.
For example, as shown in FIG. 10, a middle presser cam 51 (function similar to that of the middle presser cam 31) and a cam thrust collar 52 may be used. Middle presser cam 51
Has a cylindrical portion 51a and a cam portion 51b similarly to the above-described intermediate presser cam 31, and has a ridge 51c instead of the positioning pin 31c. The intermediate presser cam 51
Is fixed to the upper shaft 3 with set screws 51d, 51d, and can be retracted by loosening the set screws 51d, 51d.

The cam thrust collar 52 is provided with the hole 3
Instead of 4a, it has a concave portion 52a into which the tip of the intermediate presser cam 31 is inserted. Also, a ridge 51c of the intermediate pressing cam 51 is provided on the inner peripheral surface of the concave portion 52a of the cam thrust collar 52.
Are formed. Then, when returning the intermediate presser cam 51 to the original position after retreating, the tip of the cylindrical portion 51a of the intermediate presser cam 51 is inserted into the concave portion 52a of the cam thrust collar 52, and the cylindrical portion 51a is inserted.
The front and rear positions of the intermediate presser cam 51 are determined by contacting the distal end surface of the intermediate presser cam with the cam thrust collar 52. Further, the tip of the cylindrical portion 51a is connected to the recess 5 of the thrust collar 52 for the cam.
If the position of the ridge 51c of the intermediate presser cam 51 does not match the position of the groove 52b of the thrust collar 52 for the cam, the tip of the cylindrical portion 51a is inserted into the concave portion 52a.
Can be inserted into the inner presser cam 5 by inserting the concave portion 52a into the tip of the cylindrical portion 51a.
The angle of 1 can also be adjusted. The cam thrust collar 52 is also fixed to the upper shaft 3 by set screws 52c, 52c.

[0092]

According to the intermediate presser mechanism of the sewing machine according to the first aspect of the present invention, an operation of moving the intermediate presser up and down during sewing using a normal intermediate presser only by moving the intermediate presser cam;
It is possible to switch between the operation of holding the intermediate presser in a lowered state during sewing by using the intermediate presser that does not move up and down during sewing. Therefore, by simply adding a mechanism that can move the position of the intermediate presser cam to the mechanism that drives the normal intermediate presser up and down using the intermediate presser cam, it is possible to switch the operation of the above two types of intermediate presser. Therefore, the configuration of the intermediate presser mechanism that can switch between two types of intermediate presser operations during sewing can be made extremely simple. By simplifying the configuration of the intermediate holding mechanism, the number of components can be reduced, the manufacturing process can be simplified, and the manufacturing cost can be reduced.

According to the intermediate presser mechanism according to the second aspect of the present invention, the drive section for driving the intermediate presser has at least two of the intermediate presser vertical movement means and the intermediate presser sewing operation means,
Even if one intermediate presser is driven from the two driving devices, only one intermediate presser link mechanism is used as a transmission means for transmitting the driving force from these two driving devices to the intermediate presser. The number of components can be reduced as compared with the case where two link mechanisms are used to connect the drive device and the intermediate presser. Therefore, according to the intermediate holding mechanism, the number of parts can be reduced, so that the manufacturing process can be labor-saving and the manufacturing cost can be reduced.

According to the intermediate presser mechanism according to the third aspect of the present invention, during the above-mentioned rest period, the sewing operation means does not transmit the rotational force of the upper shaft to the intermediate presser, and substantially the intermediate presser. The sewing operation means has stopped transmitting between the upper shaft and the intermediate presser. Therefore, conversely, even if the upper shaft stops at the rotation angle corresponding to the suspension period, the urging force for urging the intermediate presser downward is not transmitted to the intermediate presser via the intermediate presser sewing operation means. Thereby, it is possible to prevent the upper shaft from rotating due to the urging force of the spring or the like for urging the intermediate presser downward.

According to the intermediate holding mechanism of the sewing machine according to the fourth aspect of the present invention, basically, a surface is formed in which the intermediate pressing driving means which follows the cam surface of the intermediate pressing cam does not move. As a result, in the motion curve corresponding to the rotation angle of the upper shaft of the intermediate presser by the intermediate presser cam, a portion that is a horizontal straight line in which the intermediate presser does not move up and down is provided as the above-mentioned pause period. Therefore, the rotation of the upper shaft as described above can be prevented by a very simple method of slightly changing the shape of the middle presser cam. That is, the rotation of the upper shaft as described above can be prevented without increasing the number of parts and increasing the cost.

According to the intermediate presser mechanism of the sewing machine according to the fifth aspect of the present invention, at the top dead center of the intermediate presser and its vicinity,
Since the transmission between the upper shaft and the intermediate presser is substantially not performed or only slightly performed by the intermediate presser sewing operation means, the rotation angle of the upper shaft, which is the top dead center of the intermediate presser, increases. By making the rotation angle approximately equal to the rotation angle at which the shaft stops, it is possible to prevent a rotation force that exceeds the resistance of the drive system (direct drive) applied to the upper shaft from being applied to the upper shaft.

Further, depending on the sewing machine, as described above, not only does the rotation of the upper shaft stop when the rotation angle of the upper shaft is near 53 degrees, but also the rotation angle of the upper shaft becomes the needle bar top dead center. In some cases, the upper axle can be stopped when the upper presser is stopped.However, by setting the top dead center of the center presser between the stop rotation angles of the above two upper presses, the center presser becomes the upper dead center. The rotation angle of the upper shaft and the two rotation stop angles are closer to each other, and the rotation force applied to the upper shaft from the intermediate presser sewing operation means at the two rotation stop angles can be made as small as possible, Even if a rotational force is applied, it is possible to prevent the magnitude of the rotational force from becoming larger than the magnitude of the resistance force that resists the rotation applied to the upper shaft from a drive system or the like.

That is, it is possible to prevent the upper shaft from being rotated by the force flowing backward from the intermediate presser sewing operation means.
In the case where the intermediate presser is driven by the intermediate presser cam as described in claim 4 above, the intermediate presser can be moved to the upper shaft only by changing the mounting angle of the intermediate presser cam to the upper shaft. The rotation force can be stopped from the sewing operation means,
The upper shaft can be stopped at a precise position with little cost and effort.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an external appearance of a sewing machine having an intermediate presser mechanism of a sewing machine according to an embodiment of the present invention.

FIG. 2 is a side view showing a middle presser mechanism of the sewing machine of the above example arranged inside the machine frame of the sewing machine.

FIG. 3 is an exploded perspective view showing a middle holding mechanism of the sewing machine of the above example.

FIG. 4 is a side view showing a middle press mechanism of the sewing machine of the above example.

FIG. 5 is a side view showing a middle presser mechanism of the sewing machine of the above example.

FIG. 6 is a side view showing the middle presser mechanism of the sewing machine of the above example.

FIG. 7 is a perspective view showing a middle press cam in the middle press mechanism of the sewing machine of the above example.

FIG. 8 is a drawing showing a movement curve of the intermediate presser in the intermediate presser mechanism of the sewing machine of the above example.

FIG. 9 is a drawing showing a rotational force from the intermediate presser to the upper shaft in the intermediate presser mechanism of the sewing machine of the above example.

FIG. 10 is a perspective view showing a modified example of the middle press cam in the middle press mechanism of the sewing machine of the above example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Sewing machine 3 Upper shaft 6 Holding mechanism (holding means) 7 Sewing machine needle 10 Intermediate presser mechanism 11 Intermediate presser support section 12 Intermediate presser 20 Drive section, intermediate presser sewing operation means) 31 Intermediate presser cam 32 Intermediate presser drive arm (intermediate presser driving means) 51 Cam

Claims (5)

[Claims] 1. A holding means for holding an object to be sewn, and moving the holding means in a horizontal direction so as to move up and down to an arbitrary position of the object to be sewn held by the holding means by rotation of an upper shaft. Feed means for allowing a sewing needle to be pierced, the sewing machine provided by the sewing machine needle moving along the horizontal direction with respect to the sewing machine needle moving up and down, so that a stitch provided by the sewing machine needle can be formed along an arbitrary shape. A presser for holding the workpiece downward in the vicinity of the sewing needle, and a presser mechanism for driving the presser. A middle press sewing operation means for moving the middle press up and down in accordance with the vertical movement of the sewing machine needle during sewing; the middle press sewing operation means includes a middle press cam rotating integrally with the upper shaft; , A middle presser driving means for acting as a follower of the presser cam and driving the middle presser up and down in response to the rotation of the upper shaft, wherein the intermediate presser cam contacts the middle presser driving means and The intermediate presser can be moved between a position at which the intermediate presser can be driven up and down and a position apart from the intermediate presser driving means and at which the intermediate presser keeps holding the workpiece down. The intermediate presser mechanism of the sewing machine. 2. A holding means for holding an object to be sewn, and moving the holding means in a horizontal direction so as to be vertically moved to an arbitrary position of the object to be sewn held by the holding means by rotation of an upper shaft. Feed means for allowing a sewing needle to be pierced, the sewing machine provided by the sewing machine needle moving along the horizontal direction with respect to the sewing machine needle moving up and down, so that a stitch provided by the sewing machine needle can be formed along an arbitrary shape. A presser for holding the workpiece downward in the vicinity of the sewing needle, and a presser mechanism for driving the presser. A drive unit for driving the intermediate presser up and down, and one intermediate presser link mechanism for moving the intermediate presser up and down by transmitting a movement from the drive unit to the intermediate presser; The structure is such that the middle presser is lowered during sewing so that the workpiece can be pressed downward, and while the sewing is stopped, the middle presser can be raised and the sewing object can be attached to and detached from the holding means. A middle presser vertical moving means for setting a state, and the middle presser which presses the sewing object downward during sewing in accordance with the vertical movement of the sewing machine needle, and when the sewing machine needle is raised. And a middle presser sewing operation means for facilitating horizontal movement of the workpiece. 3. A holding means for holding an object to be sewn, and moving the holding means in a horizontal direction so as to be vertically moved to an arbitrary position of the object to be sewn held by the holding means by rotation of an upper shaft. Feed means for allowing a sewing needle to be pierced, the sewing machine provided by the sewing machine needle moving along the horizontal direction with respect to the sewing machine needle moving up and down, so that a stitch provided by the sewing machine needle can be formed along an arbitrary shape. A presser for holding the workpiece downward in the vicinity of the sewing needle, and a presser mechanism for driving the presser. A presser supporting means for vertically supporting the presser while the presser is urged downward; and rotating the upper shaft to the presser being urged downward by the presser during sewing. To be transmitted Intermediate presser sewing operation means for moving the intermediate presser up and down is provided.In the vertical movement of the intermediate presser corresponding to the rotation of the upper shaft by the intermediate presser sewing operation means, the rotation angle of the upper shaft is reduced when sewing is stopped. An intermediate presser mechanism for a sewing machine, wherein a suspension period for temporarily suspending the vertical movement of the intermediate presser is provided near a predetermined rotation angle at which the upper shaft stops. 4. The middle presser sewing operation means is a middle presser cam that rotates integrally with the upper shaft and a follower of the middle presser cam, and transmits the movement from the intermediate presser cam to the middle presser. And a cam surface of the intermediate presser cam, which is in contact with the intermediate presser drive means, is formed with a surface for stopping the vertical movement of the intermediate presser during the idle period. Item 3. The intermediate presser mechanism of the sewing machine according to Item 3. 5. A holding means for holding an object to be sewn, and moving the holding means in a horizontal direction so as to be vertically moved to an arbitrary position of the object to be sewn held by the holding means by rotation of an upper shaft. Feed means for allowing a sewing needle to be pierced, the sewing machine provided by the sewing machine needle moving along the horizontal direction with respect to the sewing machine needle moving up and down, so that a stitch provided by the sewing machine needle can be formed along an arbitrary shape. A presser for holding the workpiece downward in the vicinity of the sewing needle, and a presser mechanism for driving the presser. A presser supporting means for vertically supporting the presser while the presser is urged downward; and rotating the upper shaft to the presser being urged downward by the presser during sewing. To be transmitted A middle presser sewing operation means for moving the intermediate presser up and down, wherein the rotation angle of the upper shaft, which becomes the top dead center of the intermediate presser moving up and down, is close to a predetermined rotation angle at which the upper shaft stops when sewing stops. Or a rotation angle of the upper shaft serving as a top dead center of the sewing machine needle, and a predetermined rotation angle at which the upper shaft stops. mechanism.