JPS637191Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention consists of a feed dog that can feed four movements in order to transport the work cloth in cooperation with a presser foot attached to the lower end of the presser bar, and This invention relates to a sewing machine capable of feeding a lower needle, which is equipped with a lower needle that can come out and retract from the upper surface of the throat plate in conjunction with the four-movement feed of a feed dog in order to pierce and transfer cloth.

[Prior Art] Conventionally, as a sewing machine of this type, a sewing machine described in the specification of Utility Model Application No. 86832/1983 filed by the present applicant has been proposed. In this proposed sewing machine, the lower needle performs four-movement feeding together with the feed dog, and is configured to move relative to the feed dog when piercing the work cloth. This lower needle feed allows you to reliably pierce thick work cloth or multiple sheets of work cloth and forcibly transfer it.
It is possible to prevent sewing errors that occur when sewing a plurality of pieces of work cloth.

[Problems to be solved by the invention] The proposed sewing machine described above is extremely effective in preventing misaligned stitches, but the sewing machine also has problems when inserting and removing workpiece cloth from the sewing location. was left behind. That is, insertion and removal of the workpiece cloth is performed with the sewing needle stopped at the upper position and the presser foot raised; however, in this state, the lower needle protrudes from the upper surface of the throat plate.
The gap between the tip of the lower needle and the lower surface of the presser foot is extremely small, and it is difficult to insert and remove the work cloth through that gap. Moreover, it is not possible to accurately position the workpiece cloth at the sewing location so that the desired position of the workpiece cloth coincides with the drop point of the sewing needle.

[Purpose of the invention] The present invention was devised in view of the above-mentioned problems, and its purpose is to provide a sewing machine capable of feeding the lower needle and allowing easy insertion and removal of workpiece cloth.

[Means for Solving the Problems] In order to achieve the above-mentioned object, the present invention has arm parts at both ends and is rotatably arranged on a feed base on which a feed dog is placed in the middle part. , an operating lever with a lower needle provided on one arm, an elastic body that constantly biases the operating lever in a direction in which the lower needle descends from the upper surface of the throat plate, and the other arm of the operating lever that comes into contact with the operating lever. The movable member is disposed below the needle plate and is selectively movable between an activated position and an inoperative position separated from the other arm. in the inactive position,
The presser foot lifting lever is characterized by being provided with a coupling mechanism that operatively connects the presser foot lifting lever and the moving member in order to displace the moving member to the operating position in connection with the lowering operation of the presser foot lifting lever.

[Function] Due to the feature of the present invention, when the presser foot lifting lever is operated upward with the sewing needle stopped at a predetermined upper position in order to insert and take out the work cloth, the movable member is moved to the inoperative position. The actuating lever is rotated by the biasing force of the elastic body, and the lower needle is lowered from the upper surface of the throat plate. In this state, since there is a sufficient gap between the upper surface of the throat plate and the lower surface of the presser foot, the work cloth can be handled smoothly as in the normal case without using the lower needle. When the presser foot lifting lever is lowered after the insertion position of the work cloth is completed, the movable member is displaced to the operating position in connection with the lowering operation, thereby enabling four-movement feeding of the lower needle.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 shows the external appearance of a sewing machine that can feed the lower needle, and on the top surface of the head 11 of the sewing machine frame 10 is a presser foot pressure adjustment dial 12 that can be rotated to adjust the presser foot pressure on the workpiece cloth. is placed, and its head 11
A presser foot pressure display device 13 is arranged on the front surface of the presser foot.
An operating body 15 is arranged on the bed portion 14 of the sewing machine frame 10 and is rotatably operable for lowering a feed dog 25, which will be described later, and disabling a lower needle 44, which will be described later. In addition, the needle bar 16 can be moved vertically and reciprocally.
A presser foot bar 17 that can be raised and lowered to which a pressing force adjusted by the presser foot pressure adjustment dial 12 is provided is provided inside the head 11, and a sewing needle 18 and a presser foot 19 are attached to the lower end of the needle bar 16 and the presser foot. They are attached to the lower ends of the rods 17, respectively.

FIG. 3 shows a workpiece cloth 21,
22, a feed table 26 on which the feed dog 25 is placed is arranged below the throat plate 23, and the left end of the feed table 26 is connected to the swing arm. 27 to the horizontal feed shaft 28, and its right bifurcated portion is connected to one arm of a swinging lever 30 that can swing on the vertical feed shaft 29 and the roller 30.
They are connected via a. With this configuration, the feed dog 25 has three rows of guide grooves 3 bored in the throat plate 23.
1a, 31b, and 31c, a known four-movement feed is performed, and in cooperation with the presser foot 19, and in synchronization with the vertical reciprocation of the sewing needle 18, a feeding movement is applied to both the workpiece cloths 21 and 22.

Next, the sewing deviation prevention device 40 provided on the feed table 26 will be explained.

Support portion 4 extending downward from the rear end of the feed dog 25
1, a two-arm actuating lever 42 is rotatably supported by a step screw 43. Its operating lever 4
The free end of one of the arm portions 42a of 2 is bent, and a receiving plate 45 for receiving the lower needle 44 is provided below the free end.
is provided. Further, a fitting groove 46 is formed at the free end of the arm portion 42a, and a curved spring 47 having one end fixed to the free end is disposed with its curved portion fitted into the fitting groove 46. 4
The other end of 7 extends to the right so that it can be pressed by an operator. The lower needle 44 is connected to the arm portion 4.
The lower needle 44 is elastically supported by the inner peripheral surface of the free end of the lower needle 2a and the curved portion of the curved spring 47, and by pressing the other end of the curved spring 47 upward in FIG. 7, the lower needle 44 can be removed. Become.

The other arm portion 42b of the operating lever 42 has a
An abutment screw 50 is attached that can come into contact with a moving member 48 disposed below the throat plate 23. A coil spring 52 is wound around the shoulder screw 43, and one end of the coil spring 52 is hooked to one arm portion 42a of the operating lever 42, and the other end is hooked to the support portion 41. As a result, the operating lever 42 is always urged by the coiled spring 52 in the direction in which the lower needle 44 is lowered from the upper surface of the throat plate 23, that is, in the clockwise direction in FIG. Also,
In order to restrict clockwise rotation of the actuation lever 42, a restriction protrusion 53 that can be engaged with one arm 42a of the actuation lever 42 is formed to protrude from the rear of the support part 41.

As is clear from FIG.
It is arranged so as to be able to constantly engage with the left end surface of the central guide groove 31b extending in the cloth feeding direction.
Further, the lower needle 44 is inserted into the guide groove 31 as shown in FIG.
When the lower needle 44 rises while being guided by the left end surface of
In order to prevent interference between the presser foot 19 and the presser foot 19, a notched groove 54 is provided in the portion of the presser foot 19 facing the lower needle 44.
is formed.

A configuration for connecting the operating body 15 to the moving member 48 and the feed dog lowering mechanism 60 will be described with reference to FIGS. 6 and 7.

A support protrusion 61 is formed inside the bed portion 14, and a rotation shaft 6 fixed to the operating body 15 is inserted into a through hole (not shown) bored in the support protrusion 61.
2 is inserted. Further, the operating body 15 is configured to be held at one of two operating positions by a position holding means (not shown). Connecting body 63 fitted into the rotation shaft 62
is integrally fixed to the rotating shaft 62 by a fixing plate 64 and a screw 65 that fit into a notch formed in the lower end of the rotating shaft 62, and the free end of the connecting body 63 is attached to the connecting rod 66. It is rotatably connected to one end of the . A coil spring (not shown) is provided between the connecting rod 66 and the lower surface of the support protrusion 61, and constantly biases the operating body 15 toward the bed portion 14.

A feed dog sinking mechanism 6 is provided to change the maximum amount of protrusion of the feed dog 25 from the upper surface of the throat plate 23.
0, and this sinking mechanism 60 has fitting holes 69 and 70 of the same diameter drilled in the other arm of the swing lever 30 and the swing body 68 fixed to the vertical feed shaft 29, respectively. It has an actuating rod 71 fitted into both fitting holes 69 and 70. The operating rod 7
A large diameter portion 71a that matches the fitting holes 69 and 70 and a small diameter portion 71b that is thinner than the large diameter portion 71a are continuously formed at the left end of the actuating rod 71, and the right end of the actuating rod 71 is separated from the connecting rod 66. They are connected by pins 72. On the other hand, the moving member 48 is supported by a guide support plate 73 so as to be movable in the left-right direction in FIG. In order to connect the moving member 48 and the connecting rod 66, two rotating levers 74 and 75 are rotatably attached to a support protrusion 76 formed inside the bed portion 14 by a stepped screw 77. The rotating lever 74 has a bent portion 74a that is bent upward and extends horizontally in FIG.
The bent portion 74a is rotatably connected to the right end portion of the moving member 48. The rotating lever 75 has a bent portion 75a bent downward in FIG.
It is disposed so as to engage with a locking portion 78 formed on the left end of. A coil spring 79 is attached to the support protrusion 7 in order to elastically connect both rotating levers 74 and 75.
6, and both ends of the coiled spring 79 are connected to both rotary levers 74 so that the rotary lever 74 is pressed against a regulating bent portion 75b bent at the side end of the rotary lever 75. , 75. Also,
The rotating lever 75 is always biased counterclockwise in FIG. Ru.

Next, move member 48 and presser foot lifting lever 8, which will be described later.
1 and 5 to 7, a linking mechanism 82 for operatively linking the linking mechanism 82 and the linking mechanism 82 will be described with reference to FIG. 1 and FIGS. 5 to 7.

FIG. 5 shows the fabric presser mechanism with the face plate of the head 11 of the sewing machine removed, and it is possible to perform a lifting operation to raise the presser foot 17 and a lowering operation to lower the presser foot 17. A known presser foot lifting lever 81 is rotatably attached to the head 11 of the sewing machine by a support shaft 83.
The upper surface of the proximal end of the presser bar holder 84 is engaged with a horizontally extending portion 84a of a presser bar holder 84 fixed to the presser bar 17. Further, an upwardly extending portion 84b is formed on the presser bar holder 84, and a pin 85 is fixed to the tip end portion of the upwardly extending portion 84b.
Above the sewing machine frame 10 is a first connecting lever 8.
6 is rotatably supported by a step screw 87, and the pin 85 is inserted into a long hole 88 formed at one end of the pin 85.
is inserted. Below the sewing machine frame 10,
A second connecting lever 89 is supported by a support shaft 90, and one end thereof is connected to the first connecting lever 86.
is connected to the other end by a connecting rod 91,
The other end is connected to the rotating lever 74 by a flexible connecting line 92. Therefore, in this embodiment, the connection mechanism 82 is connected to the presser bar holder 8.
4, first and second connecting levers 86 and 89, a connecting rod 91, and a flexible connecting line 92.

The operation of this embodiment configured as detailed above will be explained.

Now, in order to sew together two pieces of work cloth 21 and 22 with long piles, such as velvet, which tend to have loose stitches, rotate the presser foot adjustment dial 12 to set the presser foot pressure on the work cloth to the weakest level. In addition, the operating body 15
is rotated to rotate the connecting body 63 from the two-dot chain line position shown in FIG. 7 to the solid line position. This operating body 1
5, the rotating levers 74, 75 are moved to the position shown in FIG. 7 against the tension spring 80, and the moving member 48 is mounted on the other arm 42b of the operating lever 42 as shown in FIG. The actuating rod 7 is displaced to the operating position P1 where it can come into contact with the abutting screw 50
1 connects the small diameter portion 71b to the fitting hole 69 of the swing lever 30.
The feed dog 25 is placed in a sunken state in which the maximum protrusion amount of the feed dog 25 is reduced.

When the sewing machine is started in this state, the sewing needle 18 reciprocates up and down, the horizontal feed shaft 28 and the vertical feed shaft 29 swing, and the feed dog 25 moves in four motions in a predetermined phase relationship with the up and down reciprocation. I do. When the feed dog 25 is in a position lower than the upper surface of the throat plate 23, the lower needle 44 has its tip aligned with the guide groove 31.
The contact screw 50 is engaged with the left end surface of the moving member 48 and is slightly inclined with respect to the throat plate 23.
is opposite to it below. When the feed dog 25 subsequently rises, the operating lever 42 moves up integrally with the feed dog 25 without rotating. Due to this upward movement, the abutment screw 50 comes into contact with the lower surface of the movable member 48, and the operating lever 42 rotates counterclockwise in FIG. 31b, the above-mentioned inclined position is changed to a position perpendicular to the throat plate 23 against the action of the curved spring 47. Also,
The lower needle 44 is moved to the feed dog 2 by rotation of the operating lever 42.
5, and as a result, the work cloths 21, 22 are pierced at a speed sufficiently faster than the rising speed of the feed dog 25, as shown in FIG.
The abutment screw 50 is adjusted so that the lower needle 44 pierces the work cloths 21 and 22 almost simultaneously with the protrusion of the feed dog 25 from the upper surface of the throat plate 23.

At the point when the lower needle 44 slightly rises from the position shown in FIG. 4 and completes the piercing operation of the work cloths 21 and 22, the feed dog 25 changes from an upward movement to a horizontal forward feeding movement, and both work cloths 21, 22 are moved forward. 22 is sent to the left from the position shown in FIG. After this horizontal forward movement is completed, the feed dog 25 is lowered and the operating lever 42 is rotated back clockwise by the action of the coiled spring 52. Then, the lower needle 44 descends relative to the feed dog 25 due to the return rotation of the operating lever 42, and is pulled out from the workpiece cloths 21, 22 at a speed sufficiently faster than the descending speed of the feed dog 25. Feed dog 2
When the lower needle 5 completes its downward movement and sinks from the upper surface of the throat plate 23, the lower needle 44 retreats to a lower position completely separated from the work cloths 21 and 22. With the lower needle 44 retracted, the feed dog 25 performs a horizontal backward feed movement, thereby completing one cycle of four-movement feed. This four-movement feed accompanied by the pricking operation of the lower needle 44 is repeatedly executed while sewing the workpiece cloths 21 and 22, and is carried out from the feed dog 25 without causing any deviation in the feed amount between the workpiece cloths 21 and 22. The feeding movement is reliably applied to both work cloths 21 and 22.

Here, in order to replace the long-pile work cloth such as velvet with a normal work cloth, the operation of the sewing machine is stopped and the sewing needle 18 is stopped at a predetermined upper position. At this time, the lower needle 44 protrudes from the upper surface of the throat plate 23 and is stopped in a state where it pierces the work cloths 21 and 22. Thereafter, when the presser foot lifting lever 81 is operated to raise, the presser foot bar holder 84 and the presser foot bar 17 are raised, and the presser foot 19 is stopped at a predetermined upper position with a sufficient distance from the throat plate 23. On the other hand, as the presser bar holder 84 rises, the first connecting lever 86
is rotated clockwise in FIG.
2 to the right in Figure 1. Then, the rotating lever 74 is rotated counterclockwise in FIG. 7 against the coil spring 79, and the movable member 48 is moved to the right and separated from the abutment screw 50 as shown in the dashed double dotted line in FIG. It retreats to the inoperative position P2 shown in . As a result, the operating lever 42 is rotated clockwise in FIG. 4 by the action of the coiled spring 52, and stops with one arm 42a engaged with the regulating protrusion 53, whereby the lower hand 44 is processed cloth 21,2
2 and stop at a position below the upper surface of the throat plate 23. Note that in this embodiment, the operating body 1
The holding force of the position holding means for holding the operating position of 5 is set to be sufficiently larger than the combined spring force of the coil spring 79 and the tension spring 80, and the rotation of the rotation lever 74 against the coil spring 79 is The rotary lever 75 does not rotate even during the movement, and the feed dog lowering mechanism 6 is operated only in accordance with the operation of the operating body 15.

As described above, when the presser foot 19 is sufficiently separated from the throat plate 23 and the lower needle 44 is working from the upper surface of the throat plate 23, the operator can take out the long-pile work cloth with the lower needle 44. This can be done smoothly without interference, and the work cloth can be accurately positioned so that a predetermined position on the ordinary work cloth coincides with the drop point of the sewing needle 18. After the positioning of the work cloth is completed, when the presser foot lifting lever 81 is lowered, the presser foot holder 84 and the presser foot 17 are worked by the action of a presser spring (not shown), and the presser foot 1
9 comes to press the work cloth. Further, as the presser bar holder 84 is processed, the first connecting lever 86 is rotated counterclockwise in FIG. 1, and in conjunction with this, the second connecting lever 89 is also rotated counterclockwise. Ru. Then, the rotating lever 74 is rotated clockwise in FIG. 7 by the action of the coiled spring 79, and the moving member 48 is moved to the left to bring its tip into contact with the side edge of the abutment screw 50. It will stop in this state. In this state, the lower needle 44 is held at a position lower than the upper surface of the throat plate 23.

Now, in order to sew ordinary work cloth, the presser foot pressure adjustment dial 12 is rotated to adjust the presser foot pressure according to the thickness of the work cloth and the number of sheets, and the operating body 15 is rotated. The connecting body 63 is rotated to the position shown by the two-dot chain line in FIG. At this time, connecting rod 6
6 moves to the left and inserts the large diameter part 71a of the actuating rod 71 into the fitting hole 69 of the swing lever 30, and the large diameter part 71a matches the fitting hole 69 and the swing lever 3
Change the 0 swing angle position. As a result, the four-movement feed locus of the feed dog 25 relative to the throat plate 23 is shifted upward, and the maximum protrusion amount of the feed dog 25 is increased. Further, as the connecting rod 66 moves to the left, the rotating levers 74 and 75 are rotated counterclockwise in FIG. 7 by the action of the tension spring 80, and the moving member 48 is guided by the guide support plate 73. and move to the right. As a result, the movable member 48 moves to the abutment screw 5
It retreats again to the inoperative position P2, which is distant from 0.

When the sewing machine is started to start the sewing work, the feed dog 25 performs a known four-movement feed in synchronization with the up and down reciprocation of the sewing needle 18, and the presser foot 19
The processed fabric is transported in cooperation with the During this time, the operating lever 42 is held in a state in which one arm 42a thereof is engaged with the regulating protrusion 53 by the action of the coil spring 52, and as described above, the movable member 48 is
Since it is separated from 0, the operating lever 42 is not rotated even during the rising period of the feed dog 25. Therefore, the lower needle 44 only moves up and down integrally with the feed dog 25, and does not protrude from the upper surface of the throat plate 23 and pierce the work cloth.

In addition, when the presser foot lifting lever 81 is raised to change the sewing position of the workpiece cloth after sewing the workpiece cloth with a long pile, and the sewing operation is performed thereafter, the movable member 48 moves to the tip of the workpiece as described above. However, when the feed dog 25 reaches the lowest position for the first time after the sewing machine starts operating, the movable member 48 is moved by the coil spring 79.
As a result of the action of FIG. 4, it is completely displaced to the operating position P1 shown in FIG. As a result, the lower needle feed described above is executed.

The present invention is not limited to the above-described embodiments, and various changes can be made without departing from the spirit thereof.

For example, in this embodiment, the operating lever 42 is provided on the feed bar 26 via the support portion 41 of the feed dog 25, but it is of course possible to provide the operating lever directly on the feed bar instead. It is. Also,
In this embodiment, the presser bar holder 84 and the moving member 4
8 are connected to each other by a large number of rotating levers 86, 89 and a flexible connecting line 92, but they can also be connected by a single flexible connecting line.

[Effects of the invention] As is clear from the detailed description above, the present invention has the following advantages: By providing a connection mechanism that connects the presser foot lifting lever with a movable member that can be displaced between the lower and lowered positions, the presser foot can be raised by a single lifting operation of the presser foot lifting lever. At the same time, the lower needle can be lowered from the upper surface of the throat plate by displacing the movable member to the inoperative position, allowing the operator to smoothly insert and take out the work cloth without getting it caught on the lower needle. Moreover, the positioning of the workpiece cloth at the sewing location can also be performed accurately.

[Brief explanation of the drawing]

The drawings show a sewing machine capable of feeding the lower needle, which is an embodiment of the present invention.
The figure is a front view showing the external appearance of the sewing machine, Figure 3 is a partial sectional view showing the state in which the work cloth is transferred using the lower needle, Figure 4 is a sectional view taken along line A-A in Figure 3, and Figure 5 The figure is a left side view showing the connection structure between the presser foot lifting lever and the connection mechanism with the face plate of the head of the sewing machine removed, and FIG. 6 is the connection structure between the connection mechanism, the moving member, and the feed dog sinking mechanism. FIG. 7 is a front view showing the sewing machine frame with a part cut away, and FIG. 7 is a bottom view showing the connection structure shown in FIG. 6 from below the bed part. 10: Sewing machine frame, 17: Presser foot, 19: Presser foot, 21, 22: Processing cloth, 23: Throat plate, 25:
Feed dog, 44: Lower needle, 48: Moving member, 60: Feed dog sinking mechanism, 74, 75: Rotating lever, 77:
Step screw, 79: Winding spring, 81: Presser foot lifting lever, 82: Connection mechanism, P1: Operating position, P2: Inactive position.

Claims (1)

[Utility Model Claims] 1. A presser foot lift lever 8 that is always elastically biased downward.
A presser bar 17 that can be raised and lowered by operating the presser bar 1, and a cloth presser foot 19 attached to the lower end of the presser bar 17.
The needle plate 23 is provided with guide grooves 31a, 31b for transporting the workpiece cloths 21, 22 in cooperation with the guide grooves 31a, 31b.
In a sewing machine having a feed dog 25 capable of four-way feed via a feed dog 31c, the sewing machine has arms 42a and 42b at both ends,
An operating lever 4 is rotatably disposed on a feed base 26 on which the feed dog 25 is placed at its middle portion.
2, and one arm 4 of the operating lever 42 located opposite the guide groove 31b so as to be able to appear and disappear from the upper surface of the needle plate 23 through the guide groove 31b.
2a, a lower needle 44, an elastic body 52 which constantly urges the actuating lever 42 in a direction in which the lower needle 44 sinks from the upper surface of the needle plate 23, and a spring 54 which is attached to the actuating lever 42 to raise and lower the lower needle 44 in association with the four-motion feed of the feed dog 25.
2. The arm 42b of the second embodiment can come into contact with the arm 42b at the operating position P
a movable member 48 disposed below the needle plate 23 and selectively displaceable to either a position P1 at which the lower needle 44 is lowered from the upper surface of the needle plate 23 or a position P2 at which the lower needle 44 is lowered from the upper surface of the needle plate 23, and a connecting mechanism 82 operatively connecting the presser foot lifting lever 81 and the movable member 48 to displace the movable member 48 to the inoperative position P2 when the presser foot lifting lever 81 is raised to raise the presser bar 17, and to the operative position P1 when the presser foot lifting lever 81 is lowered to lower the presser bar 17. 2 The movable member 48 is operatively connected to a feed dog lowering mechanism 60 via a connecting means which is displaceable to disable the up and down feed movement of the feed dog 25, and the connecting means is a connecting mechanism 82 which connects the movable member 48 to the feed dog lowering mechanism 60 via a connecting means which is connected to two rotating levers 7 pivotally supported by a fixed shaft 77 on the sewing machine frame 10.
4, 75 and an elastic body 79 connecting the two pivot levers 74, 75 so that they can rotate together, and when the feed dog lowering mechanism 60 is displaced, the moving member 48 is displaced by the integral rotation of the two pivot levers 74, 75, and when the presser foot lifting lever 81 is operated to rise, only the moving member 48 is displaced to the inoperative position P2 against the elastic force of the elastic body 79.