JP2000254375A - Intermittent presser device of sewing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control the load fluctuation of the power source of an intermittent presser device of a sewing machine for vertically moving the presser bar with the power fed from a power source. SOLUTION: A slider 15 moves upward/downward with the power fed from a power source. One end 21a of a first link 21 moves upward/downward integrally with the slider 15, and a third link 27 oscillates around a shaft 35a fixed to a support member 31. The other ends 21b, 23b and 27b of the first link 21, a second link 23 and the third link 27 respectively are connected to one another oscillatably by way of a pin 33. Accordingly, the pin 33 moves along a circular locus L following the vertical movement of the slider 15, a presser bar 25 moving upward/downward integrally with one end 23a of the second link 23. And since a presser spring 47 energizes the shaft 35a, which doesn't move along the vertical movement of the presser bar 25, downward together with the support member 31, the operation to move the presser bar 25 vertically can be executed without regard to the energizing force of the presser spring 47.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intermittent holding device for a sewing machine that moves a presser bar up and down using power supplied from a power source, and more particularly, to bias the presser bar downward at a predetermined pressurizing pressure. The present invention relates to an intermittent holding device for a sewing machine that can perform the operation.

[0002]

2. Description of the Related Art Conventionally, there have been proposed various types of intermittent holding devices for moving a presser bar up and down by using power supplied from a power source. In this type of device, a presser bar is pressed at a predetermined pressurizing pressure. It needs to be biased downward. By performing this biasing, the work cloth on the bed can be pressed by a presser foot or the like attached to the lower end of the presser bar, and good sewing can be performed. Conventionally, even with a sewing machine having this type of intermittent holding device, similarly to a general sewing machine that raises and lowers the presser foot manually, an urging member such as a presser spring is provided directly on a presser bar to perform the above-described urging. Was.

[0003]

However, when the presser bar is moved up and down using the power supplied from the power source, the presser bar is raised against the above urging force when the presser bar is raised, and the urging force is used when the presser bar is lowered. The load of the power source fluctuates because the presser bar is moved with the help of the power source. For this reason, if an attempt is made to obtain an excessively large pressing pressure, the load fluctuation of the power source becomes excessive, which may impair the mechanism, and there is a limit to the obtained pressing pressure. Further, when the power is supplied from a power source common to the power for moving the needle bar up and down, the vertical movement speed of the needle bar fluctuates due to the load fluctuation, which may adversely affect the formation of the seam.

Accordingly, an object of the present invention is to provide an intermittent holding device for a sewing machine in which a presser bar is moved up and down using motive power supplied from a motive power source.

[0005]

According to a first aspect of the present invention, there is provided an intermittent presser for a sewing machine which moves a presser bar up and down using power supplied from a power source. A link mechanism that transmits the power to the presser bar and moves the presser bar up and down, and an urging member that urges a fulcrum of the link mechanism that does not move when the presser bar moves up and down, It is characterized by having.

In the present invention having the above-described structure, the power supplied from the power source is transmitted to the presser bar via the link mechanism, and the presser bar moves up and down. The urging member urges the fulcrum of the link mechanism, which does not move when the presser bar moves up and down, downward. Therefore, the power source does not oppose or assist the urging force of the urging member when moving the presser bar up and down, and can move the presser bar up and down irrespective of the urging force. Therefore, according to the present invention, load fluctuation of the power source can be satisfactorily suppressed. Further, when the presser bar is pressed upward from the presser foot side, an upper pressing force is applied to the entire link mechanism including the fulcrum. In this case, since the urging force of the urging member is opposed to the urging force of the urging member, it can be seen that the urging force of the urging member works well as the pressing pressure. That is, by applying the present invention, it is possible to obtain a pressing pressure having a free magnitude without damaging a mechanism such as a power source.

According to a second aspect of the present invention, in addition to the first aspect, the power is supplied from a common power source as the power for moving the needle bar up and down. As described above, when the presser bar is moved up and down by the power supplied from the common power source and the power for moving the needle bar up and down, the load fluctuation of the power source may adversely affect the formation of the seam. Therefore, there is a strong demand for suppressing the load fluctuation.

In the present invention, in such a case, the invention of claim 1 is applied to suppress the load fluctuation, so that the effect of the invention of claim 1 appears more remarkably and the formation of a seam A new effect such as stabilizing is produced. Further, in the present invention, by sharing the power source for the needle bar and the presser bar, there is an effect that the configuration of the apparatus can be further simplified.

According to a third aspect of the present invention, in addition to the configuration of the second aspect, the link mechanism is vertically movable at one end in conjunction with the needle bar, and is swingable in accordance with the vertical movement. A first link configured, a second link configured to move up and down at one end in conjunction with the presser bar, and to be swingable in accordance with the up and down movement; and a second end configured to swing about the fulcrum. And a third link configured so as to be able to swing, and the other ends of the first link, the second link, and the third link are swingably connected to each other.

In the present invention, one end of the first link moves up and down in conjunction with the needle bar, and is configured to be swingable in accordance with the up and down movement. It is configured to be able to swing around the fulcrum that does not move when moving. Also, since the other ends of the first link and the third link are swingably connected to each other, the first link and the third link are bent with the vertical movement of the needle bar, and the other end is connected to the fulcrum. Move along a centered circular trajectory.
Further, one end of the second link is configured to move up and down in conjunction with the presser bar, and to be swingable according to the up and down movement, and the other end is connected to the other end of the first link and the second link. And swingably connected. For this reason, one end of the second link moves up and down with the movement of the other end caused by the vertical movement of the needle bar, and the presser bar can be moved up and down by this vertical movement.

In the present invention, the presser bar can be moved up and down by the power for moving the needle bar up and down and the power supplied from the common power source with the extremely simple structure using three links. . That is, as a configuration for sharing the power source, an eccentric cam is provided on the upper shaft for vertically moving the needle bar through the needle bar connecting rod, and the rotation of the upper shaft is held by the eccentric cam. In this case, the outer periphery of the eccentric cam may be seized by frictional heat during high-speed rotation. Further, since the eccentric cam needs to be provided separately from the needle bar connecting rod or the like, it also hinders downsizing of the arm portion of the sewing machine. On the other hand, in the present invention, the power source for the needle bar and the presser bar can be shared by the extremely simple configuration as described above without using an eccentric cam. Therefore, according to the present invention, in addition to the effect of the invention described in claim 2, seizure and the like can be prevented, the durability of the device can be improved, and the arm portion of the sewing machine can be favorably reduced in size. Has an effect that it is possible to design a sewing machine having no arm.

According to a fourth aspect of the present invention, in addition to the configuration of the third aspect, a supporting member for supporting the link mechanism by fixing the fulcrum and a fixing position of the fulcrum relative to the supporting member are adjusted. And an adjusting member, wherein the urging member urges the supporting point downward together with the supporting member.

In the present invention, the fixing position of the fulcrum with respect to the support member can be adjusted by the adjusting member.
Then, by adjusting the position of the fulcrum, it is possible to displace the circular trajectory in which the other end of each link moves, and the vertical movement width and the vertical movement height of the presser bar in accordance with this displacement. Can be changed. Moreover, in the present invention, since the urging member urges the supporting point downward together with the supporting member, the urging force of the urging member does not act in any direction with respect to the adjustment by the adjusting member, and the adjustment is extremely difficult. It will be easier. Further, the pressure does not change due to the above adjustment. Therefore, in the present invention, in addition to the effect of the third aspect of the present invention, there is an effect that the vertical movement width and the vertical movement height of the presser bar can be adjusted very easily.

[0014]

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 2 is a perspective view illustrating a configuration of a head 1 of the sewing machine to which the present invention is applied. The sewing machine according to the present embodiment is a so-called armless type sewing machine in which a sewing machine motor 5 as a power source for moving the needle bar 3 up and down is directly fixed to the head 1 and the conventional upper shaft and arm are omitted.

As shown in FIG. 2, the sewing machine motor 5 is directly fixed to the outside of the sewing machine frame 1a constituting the head 1, and the balancing crank 7 is directly fixed to the rotation shaft thereof. One end 11a of a needle bar connecting rod 11 is swingably connected to one end 7a of a balancing crank 7 that moves circularly in a vertical plane by rotation of the sewing machine motor 5, and the other end 11b of the needle bar connecting rod 11 is a needle. The needle bar 3 is swingably connected to the needle bar 3 via a bar holder 3a. The other end 11 b of the needle bar connecting rod 11 is connected to the guide member 1.
It is guided vertically by 3. Therefore, the needle bar 3 moves up and down according to the rotation of the sewing machine motor 5.

A slider 15 as a vertically moving member is slidably mounted on the needle bar 3. The slider 15 is connected to the needle bar connecting rod 11 via a lever 17 as described later.
, And moves up and down a little later than the needle bar 3. Also, the first link 2 is provided on the slider 15.
One end 21a of one is swingably connected. The other end 21b of the first link 21 has one end 23a (see FIG. 1) and the other end 23b of the second link 23, which is swingably connected to the holding rod 25 via a holding rod holder 25a, and one end 27a ( 3) are pivotally connected to each other by pins 33 together with the other end 27b of the third link 27 which is pivotally fixed to the support member 31 as described later.

As shown in FIG. 3, each of the links 21 to 27 is provided in a pair with the slider 15 and the presser bar 25 interposed therebetween, and the second link 23, the first link 21, and the third link 21 are arranged in this order from the inside. The links 27 are arranged in this order. Outside the third link 27 at both ends, there are provided support levers 35 for swingably supporting the third link 27 via a shaft 35a as a fulcrum.
Is swingably connected to the support member 31 via a shaft 35b provided at one end, and a screw hole 35c is formed at the other end.

Returning to FIG. 2, the support member 31 is formed in a box shape by an iron plate, and is guided vertically by the sewing machine frame 1a. Specifically, the sewing machine frame 1a
The guide member such as a roller (not shown) provided in the
The support member 31 is configured to be able to move up and down smoothly. Further, a long hole 31b is formed on the front side (left side in FIG. 2) of the support member 31, and a screw 39 is screwed into the screw hole 35c from the front side of the long hole 31b. The elongated hole 31b is formed in an arc shape along the locus of the screw hole 35c when the support lever 35 swings as described above, and the support lever 35 can be fixed to an arbitrary swing position by the screw 39. And Further, a pin 41 is provided upright on the front surface of the support member 31, and a cam 43 rotatably provided on the sewing machine frame 1a is in contact with the pin 41 from below. As shown in the front view of FIG. 1, between the upper end surface of the support member 31 and the sewing machine frame 1a, a pressing spring 4 as an urging member whose urging force can be adjusted by an adjusting screw 45 is provided.
7 are provided. Therefore, when the cam 43 is rotated, the position of the support member 31 can be adjusted vertically according to the rotation angle.

During normal sewing, the screw 39 and the cam 43
Is not operated, and the shaft 35a of the support lever 35 is fixed at a predetermined position in the sewing machine frame 1a. Therefore, in the link mechanism including the first link 21 to the third link 27, the presser bar 25 can be moved up and down as follows in accordance with the up and down movement of the slider 15.

That is, as shown in FIGS. 1 and 3, one end 21a of the first link 21 moves up and down integrally with the slider 15, and the third link 27 is a shaft fixed in the sewing machine frame 1a. It swings around 35a. Also, the first link 2
The other ends 21 b and 27 b of the first and third links 27 are pins 33.
Are swingably connected to each other. For this reason,
As the slider 15 moves up and down, the first link 21 and the third link 27 are bent, and the pin 33 moves along a circular locus L (FIG. 1) centered on the shaft 35a. Furthermore,
One end 23a of the second link 23 moves up and down in conjunction with the presser bar 25 and the other end 23b is connected to the pin 33, so that one end 23a of the second link 23 The presser bar 25 can be moved up and down by this up and down movement. For example, FIG. 4 shows a state where the slider 15 has risen from the state of FIG. 3 and the pin 33 and the presser bar 25 have risen accordingly.

As shown in FIGS. 1 and 3, the distance between the pin 33 and the mounting shaft 23c of the one end 23a of the second link 23 with respect to the presser bar holder 25a is determined by the distance between the pin 33 and the shaft 35a.
And the distance between the shaft 35b and the shaft 35a. The shaft 35b is provided with the slider 15 and the holding rod 25.
Is located at a position overlapping with the pin 33 when the bottom dead center is reached, and the lower end of the elongated hole 31b has a screw hole 35c when the shaft 35b and the pin 33 overlap and the shaft 35a and the mounting shaft 23c overlap. Corresponds to the position.

On the other hand, the slider 15 and the needle bar connecting rod 11
They are connected as follows: That is, as shown in FIG. 5, one end 17a of the lever 17 is swingably fixed to the middle of both ends 11a and 11b of the needle bar connecting rod 11, and the other end 17b of the lever 17 swings to the slider 15. It is fixed as possible. Here, due to the shape of the slider 15, the vertical movement axis of the other end 17b is eccentric with respect to the needle bar 3. The eccentric direction is such that the vertical movement axis of the other end 17b is closer to the rotation direction near the bottom dead center of the one end 11a of the needle bar connecting rod 11 than the vertical movement axis of the other end 11b of the needle bar connecting rod 11. It is arranged in. Therefore, the lever 17 transmits the vertical movement of the needle bar connecting rod 11 to the slider 15 while swinging itself, and moves the slider 15 up and down at a timing slightly delayed from the needle bar 3 as follows. Can be done.

That is, when the balance crank 7 rotates in the direction of arrow A from the bottom dead center of the needle bar 3, the other end 1 of the needle bar connecting rod 11
1b rises in the direction of arrow B integrally with the needle bar 3. At this time, the one end 17a of the lever 17 moves in the direction of arrow C along the rotation direction of the balancing crank 7 while rising, so that the lever 17 rises while swinging in the direction of arrow D. The slider 15 rises in the direction of arrow E in response to this rise, but the rise of the slider 15 is delayed by the amount of the swing of the lever 17 in the direction of arrow D. As described above, the slider 15 is slightly delayed from the needle bar 3.
Moves up and down, and as described above, the presser bar 2
In this embodiment, the presser foot 49 attached to the lower end of the presser bar 25 starts moving the needle bar 3 upward.
(FIG. 1) allows the work cloth on the bed (not shown) to be satisfactorily pressed.

Next, a method of adjusting the vertical movement width of the presser bar 25 in the head 1 configured as described above, and the presser bar 25 will be described.
A method of adjusting the height at which the vertical movement is described with reference to FIG. As described above, the shaft 35b overlaps the pin 33 when the presser bar 25 reaches the bottom dead center. For this reason, the height of the presser bar 25 at that time is uniquely determined with respect to the shaft 35b, and hence with respect to the support member 31.

From this state, the support lever 35 is swung,
A case where the position of the screw hole 35c is changed will be considered. In this case, since the shaft 35b and the pin 33 overlap each other, when the support lever 35 is swung, the third link 2 is integrally formed therewith.
7 only swings, the first link 21 and the second link 2
3 does not swing. From this, it can be understood that the bottom dead center of the presser bar 25 does not change even if the support lever 35 is swung. However, since the position of the locus L about the axis 35a changes with the swing of the support lever 35, the top dead center of the presser bar 25 also changes accordingly.

That is, in the sewing machine of the present embodiment, the support lever 35 is swung to change the position of the screw hole 35c in the long hole 31 so that the lower dead center of the presser bar 25 is not changed. Only the moving width can be changed. Further, in the present embodiment, since the pressing spring 47 urges the entire supporting member 31 downward to provide a pressing pressure described later, when the supporting lever 35 is moved within the supporting member 31 as described above. The above adjustment can be performed very easily without being affected by the urging force of the presser spring 47. Also,
Therefore, the urging force of the presser spring 47 and, consequently, the presser pressure do not change due to the above adjustment.

When the screw hole 35c is provided at the lower end of the long hole 31b, the shaft 35a and the mounting shaft 23c overlap as described above, and the second link 23 and the third link 27 swing integrally. . In this case, even if the vertical movement of the slider 15 is transmitted via the first link 21, the position of the mounting shaft 23c does not change and the state of overlapping with the shaft 35a is maintained.
The height of the presser bar 25 does not change. That is, the presser bar 25
The vertical movement width becomes 0 mm. The more the screw hole 35c is disposed along the long hole 31b, the larger the vertical movement width becomes. The screw 39 is tightened at a position corresponding to a desired vertical movement width, and the position of the screw hole 35c is fixed. Thereby, it is possible to perform sewing with the desired vertical movement width. In the present embodiment, the vertical movement width of the presser bar 25 can be adjusted to a width of 0 mm to 7.2 mm by the above configuration.

When the cam 43 is rotated, the support member 3
1 can be moved up and down. In this case, since the link mechanism including the first link 21 to the third link 27 can be moved up and down as a whole, the height at which the presser bar 25 moves up and down without changing the vertical movement width of the presser bar 25. Only the length can be changed. In addition, since the height of the one end 21a of the first link 21 does not change even if the support member 31 is moved up and down, the width of the up and down movement slightly changes strictly. Is very small with little effect.

As described above, in the sewing machine according to the present embodiment,
With the extremely simple configuration using the first to third links 21 to 27 as described above, the vertical movement width of the presser bar 25 can be changed without using an eccentric cam. Therefore, the durability of the sewing machine can be improved by preventing seizure and the like, and the design of the sewing machine having no upper shaft or arm portion as described above can be facilitated.

In this embodiment, the holding spring 47 urges the shaft 35a, which does not move when the holding bar 25 moves up and down, together with the support member 31 downward. Therefore, it is not only extremely easy to adjust the vertical movement width of the presser bar 25 by swinging the support lever 35 as described above, but also the urging force of the presser spring 47 is used to move the presser bar 25 up and down. , And the presser bar 25 can be moved up and down irrespective of the urging force. Therefore, in the present embodiment, the load fluctuation of the sewing machine motor 5 can be favorably suppressed. In addition, since the sewing machine motor 5 is also a power source for moving the needle bar 3 up and down, it is possible to stabilize the formation of the seam by suppressing the load fluctuation. By using a common power source, the configuration of the apparatus can be further simplified.

When the presser bar 25 is pressed upward from the presser foot 49 side, an upper pressing force is also applied to the support member 31 including the entire link mechanism including the first link 21 to the third link 27. In this case, since the urging force of the pressing spring 47 is opposed to the urging force of the pressing spring 47, it can be seen that the urging force of the pressing spring 47 works well as the pressing pressure. Therefore, in the sewing machine according to the present embodiment, a free pressing pressure can be obtained without requiring a large torque to the sewing machine motor 5.

In the above-described embodiment, the elongated hole 31b and the screw 39 correspond to an adjusting member. Further, the present invention is not limited to the above-described embodiment at all,
The present invention can be implemented in various forms without departing from the gist of the present invention. For example, in the above embodiment, the cam 43
Is rotated to adjust the height at which the presser bar 25 moves up and down, the adjustment is performed against the urging force of the presser spring 47 or while being pressed by the presser spring 47. On the other hand, if the shaft 35a is configured to be able to move two-dimensionally in the vertical plane in the support member 31, the influence of the urging force can be reduced even when adjusting only the height at which the presser bar 25 moves up and down. The adjustment can be easily performed without receiving.

The structure of the link mechanism for moving the presser bar 25 up and down may take various forms other than those described above. For example, in the link mechanism shown in FIG. 6, a pin 71 protrudes from the side surface of the presser bar 25, and has a horizontally elongated hole 73b at one end 73a for engaging the pin 71, and
A link 73 whose other end 73c is swingably connected to the lower end of the lever 75 is provided. The lever 75 is a member that is moved by the sewing machine motor 5 in a direction opposite to the direction of the slider 15 in the above-described embodiment.

A fulcrum 73d is provided at the center of the link 73, and a supporting member 77 for swingably supporting the fulcrum 73d is pressed against the stopper 83 from above by a pressing spring 81. Note that the presser bar 25 is supported by the guide 85 so as to be movable only in the vertical direction.

In the link mechanism configured as described above, when the lever 75 is moved up and down, the link 73 swings around the fulcrum 73d, and the elongated hole 73b moves up and down in the opposite direction to the lever 75. Thus, the presser bar 25 also moves up and down in the opposite direction to the lever 75 (that is, similarly to the presser bar 25 of the above embodiment). Also in this case, the fulcrum 73d and the support member 77 do not move when the presser bar 25 moves up and down, so that the load fluctuation can be favorably suppressed as described above. When the presser bar 25 is pressed from the presser foot 49 side,
A biasing force (pressing pressure) from the pressing spring 81 is applied around the other end 73c. Therefore, it is possible to obtain a free pressing pressure without damaging the mechanism.

In this link mechanism, since the fulcrum 73d is located at the center between the one end 73a and the other end 73c,
The vertical movement width of the lever 75 coincides with the vertical movement width of the presser bar 25, and the pressing pressure is half of the urging force of the presser spring 81. The distance between the fulcrum 73d and one end 73a and the fulcrum 73d and the other end 73
If the distance from c can be relatively changed, it is possible to adjust the vertical movement width of the presser bar 25 and the presser pressure.

Further, the slider 15 and the lever 75 in each of the above embodiments may be driven by a power source different from the sewing machine motor 5, and in this case also, the fluctuation of the load of the power source is suppressed well. Thus, it is possible to obtain a free pressing pressure without damaging the mechanism relating to the power source. Further, the lever 75 may be moved up and down by a mechanism provided with an eccentric cam on the upper shaft.

[Brief description of the drawings]

FIG. 1 is a front view schematically showing a configuration of a head of a sewing machine to which the present invention is applied.

FIG. 2 is a perspective view showing the configuration of the head in detail.

FIG. 3 is a perspective view of a link mechanism that moves a presser bar up and down from the head.

FIG. 4 is a perspective view illustrating the above-described configuration when the presser bar rises from the state of FIG. 3;

FIG. 5 is a front view illustrating a driving force transmission mechanism from the needle bar connecting rod to the link mechanism.

FIG. 6 is an explanatory view showing another form of a link mechanism for moving a presser bar up and down.

[Explanation of symbols]

1: Head 1a: Sewing machine frame 3: Needle bar
Reference Signs List 5 sewing machine motor 7 balancing crank 11 needle rod 13 guide member 15 slider 17 lever 21 first link 23 second link 25 presser bar 27 third link 31 support member 31b
Long hole 33 ... Pin 35 ... Support lever 39 ... Screw 41 ... Pin 43 ... Cam 45 ... Adjustment screw 47 ... Holding spring 49 ...
Presser foot

Continuation of front page (72) Inventor Koichi Akabane 15-1 Naeshiro-cho, Mizuho-ku, Nagoya-shi, Aichi F-term (reference) in Brother Industries, Ltd. 3B150 CE04 CE25 CE26 EA02 EA07 EA13 JA17 JA28

Claims (4)

[Claims] 1. An intermittent press device for a sewing machine that moves a presser bar up and down using power supplied from a power source, a link mechanism that transmits the power to the presser bar and moves the presser bar up and down, And a biasing member for biasing a fulcrum of the link mechanism, which does not move when the presser bar moves up and down, downwardly. 2. The intermittent holding device according to claim 1, wherein the power is supplied from a common power source as the power for moving the needle bar up and down. 3. A first link, wherein one end of the link mechanism is configured to move up and down in conjunction with the needle bar and swingable in accordance with the up and down movement, and one end of the link mechanism is linked to the presser bar. A second link configured to swing up and down and swingable in accordance with the up and down movement; and a third link configured to swing at one end about the fulcrum. The intermittent holding device according to claim 2, wherein the other ends of the first link, the second link, and the third link are swingably connected to each other. 4. A support member for supporting the link mechanism by fixing the fulcrum, and an adjusting member for adjusting a fixing position of the fulcrum with respect to the support member, wherein the urging member is a support member. 4. The intermittent holding device according to claim 3, wherein the fulcrum is urged downward.