JPH0716371A - Presser bar-lift reducing device for sewing machine - Google Patents

Abstract

PURPOSE:To prevent tingling sound, wear-out, abnormal heat generation and knocking sound at a clutch. CONSTITUTION:An input device A equipped with engaging grooves 12 and a plane plate clutch 15 is provided on the end face through which the rotation force of a reduction pulley 1 is transmitted. An output device B is equipped with a claw clutch 11 that can engage with the grooves 12 and a plane plate clutch 18 that can come in press-contact with the plane plate clutch 15 and powering devices 37 that energize the claw clutch 11 and a plane plate clutch 18. A connecting decive C connects and disconnects the input device A and the output device B. An operating device D transmits the rotation of the output device B to the following stages via an eccentric cam 6a when the connecting device C connects the input device A and the output device B. An action device E operates the operating device D to lift lower a presser foot.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a presser foot lifting reducing device for raising and lowering a cloth presser by a rotation torque of a motor.

[0002]

2. Description of the Related Art Conventionally, sewing machines have been provided with a presser foot lifting device for reducing the pressure of a pedal that causes a presser foot lifting operation. This presser foot lifting device transmits a motor driving force to a cam in the subsequent stage by connecting a clutch, and the rotation of the cam causes the cloth presser lifting link and the cloth presser linked to the cloth presser lifting link to move up and down by a predetermined amount. When the operation is done, the clutch is disengaged.

As described above, a clutch is used in the conventional presser foot lifting device, but the presser foot lifting device using this clutch is roughly classified into, for example, Japanese Patent Publication No. 62-28.
The one using a spring clutch as described in Japanese Patent No. 33, for example, the one using a friction taper clutch composed of a metal material and a cork material, for example, Japanese Patent Publication No. 64-5.
They are classified into those using a claw clutch as described in Japanese Patent No. 918, etc.

[0004]

However, the above-described conventional presser foot lifting device for sewing machine has the following problems. That is, in the reduction device using the spring clutch, when the lubricating oil is insufficient, there is a problem that chatter noise is generated between the clutch and the shaft of the partner. Moreover, in the reduction device using the friction taper clutch,
Depending on the timing, there is a problem that the torque becomes insufficient and the clutch part slips, causing wear and abnormal heat generation. Further, in the reduction device using the claw clutch, the claw clutch is inserted into the groove formed in the rotating body, that is, the fixed side claw clutch is inserted into the groove that is rotating, so that a tapping sound is generated. There is a problem.
As described above, the above-described conventional presser foot lifting reducing devices have contradictory problems.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a presser foot lifting reduction device for a sewing machine, which prevents chatter noise, wear, abnormal heat generation, and hitting noise in the clutch portion.

[0006]

In order to achieve the above object, a presser foot lifting device of a sewing machine according to the present invention has a reducing pulley which is rotated by a motor, is integrally connected to the reducing pulley, and has an engaging groove on an end face thereof. The input means formed of the formed input shaft, the input shaft flat plate clutch externally fitted and fixed to the input shaft, the flat plate clutch switching pawl provided on the outer peripheral surface and the outer peripheral surface formed along the axial direction. A long groove is provided, and a concave groove or a convex portion is formed on one end surface, an axially slidable output shaft and a through hole for a claw clutch are formed, and the through hole for the claw clutch is continuously provided in the long groove. Output shaft flat plate clutch fixed to the other end surface of the output shaft at a position, a switching cam portion slidably fitted in the long groove and protruding on the outer peripheral surface in a direction orthogonal to the sliding direction. Claw clutch provided, this claw clutch Claw urging means arranged at the other end of the claw clutch so that one end of the claw enters the engagement groove side, a convex portion or a concave groove that is always fitted to the concave groove or the convex portion of the output shaft. A fixed shaft formed on the end surface, an output shaft biasing means disposed between the fixed shaft and the output shaft, and biasing the output shaft toward the input shaft flat plate clutch; The flat plate clutch switching pawl and the switching cam portion are captured inside the tip, the pawl clutch is disengaged from the engagement groove against the pawl clutch biasing means, and the output shaft flat plate clutch is output. A stop lever provided with a plurality of stop pieces having an inclined surface for separating from the input shaft flat plate clutch against the shaft urging means, and a fitting / removing means provided so as to surround the output means; It is fixedly fitted inside the fixed shaft. And an operating shaft rotatably fitted in the input shaft, an operating cam portion provided at the other end of the operating shaft, and operating means, and interlocking with the work clamp according to the rotation of the operating cam portion. And an operating means for operating the cloth presser lifting link.

[0007]

According to the presser foot lifting / reducing device of the above-mentioned means, the switching cam portion and the flat plate clutch switching pawl are captured by the inclined surface formed on the stopper when the input means and the output means are separated. The output shaft flat plate clutch separates from the input shaft flat plate clutch while the end of the claw clutch disengages from the mesh groove. On the other hand, when the input means and the output means are connected, the switching cam portion and the flat plate clutch switching pawl, which were captured on the inclined surface, become free, and the output shaft flat plate clutch is first converted into the input shaft flat plate clutch by the output shaft biasing means. The output shaft flat plate clutch is rotated by friction while sliding on the surface of the input shaft flat plate clutch. Simultaneously with this operation, the pawl clutch is urged toward the input shaft flat plate clutch by the urging means for the pawl clutch, and the end portion of the pawl clutch rotates while sliding on the end surface of the input shaft. The clutch enters and meshes with this meshing groove. In this way, since the flat plate clutch operates before the claw clutch meshes, the meshing motion of the claw clutch is changed to the meshing motion of the rotating bodies, so that the hitting noise is reduced. Further, since the function of the flat plate clutch is only before engaging with the claw clutch, wear and abnormal heat generation are greatly reduced, and chatter noise is not generated because the spring clutch is not used.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view of a presser foot lifting reducer for a sewing machine according to an embodiment of the present invention, and FIG. 2 is an exploded perspective view of input means, output means, and operating means constituting a drive portion. Is an input means A, an output means B, a fitting / removing means C for connecting and disconnecting the two, an operating means D for transmitting the rotation of the output means B to a rear stage by a cam when the fitting / removing means C is connected, and this operation. The operation means E for raising and lowering the presser foot by the means D and the reverse rotation preventing means F constitute a main part.

The input means A has a reduction pulley 1 rotated by a V-belt 50 (see FIG. 3) wound around a drive motor (not shown), and an outer ring fitted and fixed to a mounting surface 3 of a device mounting base 2. The outer peripheral surface is fitted and fixed to the inner ring of the ball bearing 4, and a plurality of radially extending meshing grooves 12 are formed on the end surface on the side of the anti-reduction pulley (in this embodiment, the meshing grooves 12 are The input shaft 8 is fixed to the reduction pulley 1 by a set screw 10, and a set screw 14 is formed on the outer peripheral surface of the large diameter portion 13 of the input shaft 8 in which the engagement groove 12 is formed. It is configured by a flat plate friction clutch (input shaft flat plate clutch) 15 which is externally fitted and fixed by.

The output means B has a flat plate clutch switching claw 36 protruding from the outer peripheral surface thereof, a long groove 16 formed along the axial direction, and a concave groove 22 formed on the end surface on the side opposite to the input shaft. The output shaft 17 slidable in the axial direction with respect to the operation shaft 6 and the slidably fitted arrangement in the long groove 16 and the switching cam portion on the outer peripheral surface in a direction orthogonal to the sliding direction. The claw clutch 11 having a convex 35, and the claw clutch 11 on the side of the flat plate friction clutch (to the right in FIG. 1)
A spring 37 serving as a biasing means for the claw clutch that biases the
And the claw clutch 1 urged by the spring 37
A through hole 18a for the pawl clutch through which 1 can pass is formed,
A flat plate cork clutch plate (output shaft flat plate clutch) attached to the end face of the output shaft 17 on the flat plate friction clutch side so that the long groove 16 and the through hole 18a for the claw clutch are aligned with each other.
18 and the long hole 1 that allows the claw clutch 11 to slide.
An output shaft cylinder 19 which is opened at 9a and is externally fitted and fixed to the output shaft 17, a fixed shaft 20 having an end face formed with a convex portion 21 which is always fitted in the concave groove 22 of the output shaft 17, and the fixed shaft Two
0 and the output shaft 17 and a plurality of springs 39 (three in this embodiment) as output shaft urging means for urging the output shaft 17 toward the flat plate friction clutch, and a reverse rotation described later. The notch 4 which is hooked on the reverse rotation preventing claw 47 of the prevention means F.
5a are formed at a pair of symmetrical positions, and are constituted by a fixed shaft collar 45 which is externally fitted and fixed to the fixed shaft 20 (see FIG. 6).

As shown in FIG. 3, the fitting / removing means C has one end rotatably supported by the device mounting base 2 by pins 26 and 27, and is provided so as to surround the output means B.
A set of stop levers 24, 25 (in this embodiment, 2
4 is a presser foot lifting lever, 25 is a presser foot lowering lever), a connecting link 28 that connects the other ends of both 24 and 25, and has a protrusion 28a that is urged downward in the drawing by the urging force of a spring 54. , A spring 29 that is disposed in contact with the lower portion of the protrusion 28a and that has a greater biasing force than the spring 54.
Is attached to the stop levers 24 and 25 and the operating pieces 30 that are urged downward by pressing a pedal (not shown) and the inclination angle increases as the tip moves toward the fixed shaft 20. Therefore, it is constituted by the stop pieces 33 and 34 for capturing both the rotating flat plate clutch switching pawl 36 and the switching cam portion 35 (see FIG. 4).

The operating means D is fitted into the fixed shaft 20 and is integrally connected by a set screw 23, and one end is fitted into the input shaft 8 and is needle-bearing 9 and the other end is the device mount 2. As shown in FIG. 5, the operating shaft 6 rotatably supported by the respective metal portions 5 of the operating shaft 6 and the recesses 6c and 6d of the required shape provided on the end surface of the operating shaft 6 on the side opposite the anti-reduction pulley are symmetrical. It is composed of an eccentric cam portion 6a as an operation cam portion which is notched at a position.

As shown in FIG. 5, the operating means E includes an operating lever 40, one end of which is rotatably supported by a step screw 40a, and a pin at a position facing the eccentric cam portion 6a of the operating lever 40. An operation roller 41 rotatably supported by 42, a rotatably supported other end of the operation lever 40, a cloth presser lifting link 43 interlocking with the cloth presser, and the cloth presser lifting link 43 upward in the drawing. It is composed of a spring 44 that urges the operation roller 41 to constantly contact the eccentric cam portion 6a.

As shown in FIG. 6, the reverse rotation preventing means F is axially supported by a step screw 51 fixed to the device mounting base 2,
It is composed of a reverse rotation preventing claw 47 which is urged to rotate by a spring 52 so as to be constantly in pressure contact with the fixed shaft collar 45.

Next, the operation of the presser foot lifting reducing device of the above construction will be described. The input means A is
It constantly rotates in conjunction with a sewing machine motor (not shown). When the operating piece 30 is pulled down against the urging force of the spring 29, in its initial operation, the connecting link 28 is pulled downward in accordance with the urging force of the spring 54, which causes the presser foot lowering lever 25 to move.
3 and entering the rotation path of the switching cam portion 35, as shown in FIG.
It becomes the state shown in. That is, when the operating piece 30 is lowered, the presser foot lowering lever 25 is brought into contact with the output shaft cylinder 19 by the spring 54 via the connecting link 28, and the flat plate clutch switching pawl 36 and the switching cam portion 35 are moved as shown in FIG. Then, it is captured by the restraining piece 34.

As a result, the end portion 11 of the pawl clutch 11 is
a disengages from the meshing groove 12 of the input shaft 8 against the urging force of the spring 37, and the flat cork clutch plate 18
Is a flat plate friction clutch 1 against the urging force of the spring 39.
Away from 5. That is, the rotational force of the input means A is not transmitted to the output means B. Here, the relationship between the eccentric cam portion 6a and the motion roller 41 is as shown in FIG. That is, the motion roller 41 that contacts the eccentric cam portion 6a
This causes the operating lever 40 to rotate upward, and the connecting link 43
Has been moved upwards, whereby the presser foot is lowered.

Next, the operating piece 30 further includes the spring 29.
When it is pulled down against the urging force of the sewing machine, the lock of a known shut-off mechanism (not shown) is released, which starts the sewing machine. During operation of the sewing machine, the operating piece 30 is hooked at the lowered position, and when one cycle of sewing operation is completed,
The operating piece 30 is returned to the original position.

By the way, when the engagement of the operating piece 30 is released, that is, the pedal is returned along with the completion of the predetermined cycle sewing, the operating piece 30 has a biasing force of the spring 29 larger than that of the spring 54. So it can be pulled up against this. Along with this, the connecting link 28 rises,
The stop levers 24 and 25 rotate counterclockwise around the pins 26 and 27 as fulcrums, and the presser foot lowering lever 25 moves to the output shaft cylinder 1
Rise away from 9. Therefore, the stop piece 34 also rises and the switching pawl 36 for the flat plate clutch and the switching cam portion 35.
Is released, the flat plate cork clutch plate 18 is pressed against the flat plate friction clutch 15 by the urging force of the spring 39, and the claw clutch 11 is rotated by the urging force of the spring 37 to rotate and slide the large-diameter portion 13 of the input shaft 8. Crimp on.

Here, in the flat cork clutch plate 18,
The rotation of the flat plate friction clutch 15 is transmitted by friction between the plates, but because of friction transmission, the flat plate cork clutch plate 18 rotates while sliding on the flat plate friction clutch 15 to some extent. However, if it slips a little, the meshing groove 12 approaches, and the end portion 11a of the claw clutch 11 enters this meshing groove 12 and meshes with each other. At this point, the rotation of the input means A is completely transmitted to the output means B, A and the output means B rotate counterclockwise in FIG.

In this way, when the output means B rotates 180 °, the presser foot lifting lever 24 rotated upward is in contact with the output shaft cylinder 19 and is on standby, and the flat plate clutch switching pawl 36 and the switching cam. The portion 35 is now captured by the stop piece 33 of the presser foot lifting lever 24, and the end portion 11a of the pawl clutch 11 disengages from the mesh groove 12 of the input shaft 8 against the urging force of the spring 37 and the flat plate cork. The clutch plate 18 separates from the flat plate friction clutch 15 against the biasing force of the spring 39. That is, the transmission of the rotational force of the input means A to the output means B is cut off.

At this time, as shown in FIG. 6, the reverse rotation preventing claw 47 of the reverse rotation preventing means F is engaged with the notch portion 45a of the fixed shaft collar 45 to secure the stopping posture of the output means B. The stop posture is secured in the same manner when the cloth presser is further rotated by 180 ° and the cutout portions 45a formed at symmetrical positions are locked.

Further, the switching claw 36 for the flat plate clutch and the switching cam portion 35 are the stop pieces 33 of the presser foot lifting lever 24.
When the eccentric cam portion 6a and the operating roller 41 are caught by the operating roller 41, the operating lever 40 is rotated downward by the operating roller 41 contacting the recess 6c of the eccentric cam portion 6a, and the connecting link 43 is moved downward. It is moving, and as a result, the work clamp is raised.

As described above, in the present embodiment, the clutch portion is configured to use the friction clutches 15 and 18 and the pawl clutch 11 together, and the friction clutches 15 and 18 are operated before the pawl clutch 11 is engaged and the pawl clutch 11 is operated. Since the meshing operation of is the meshing operation of the rotating bodies, it is possible to reduce the hitting sound.

Further, since the friction clutches 15 and 18 function only before the claw clutch 11 is engaged, wear and abnormal heat generation can be greatly reduced.

Further, since no spring clutch is used, the fear of chattering noise is eliminated.

Although the invention made by the present inventor has been specifically described based on the embodiments, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the invention. Needless to say, for example, in the above embodiment, the output shaft 17 is provided with the concave groove 22,
The fixed shaft 20 is formed with the convex portions 21 that are always fitted in the concave grooves 22, but the convex portion is formed on the output shaft 17.
You may make it form the recessed groove which fits in this convex part in the fixed shaft 20.

Further, in the above embodiment, the long groove 16 is formed so as to penetrate both end faces of the output shaft 17, but as described in Japanese Patent Publication No. 64-5918, the end face on the input shaft 8 side is formed. It is also possible to form a long groove having an open shape.

[0028]

As described above, according to the presser foot lifting / reducing device of the present invention, the lightening pulley rotated by the motor and the input which is integrally connected to the lightening pulley and has the meshing groove formed on the end surface thereof. An input shaft, an input shaft flat plate clutch externally fitted and fixed to the input shaft, an input means, a flat plate clutch switching pawl provided on the outer peripheral surface, and a long groove formed along the outer peripheral surface in the axial direction, A concave groove or a convex portion is formed on one end surface, and an output shaft slidable in the axial direction and a through hole for a pawl clutch are formed, and the output is provided at a position where the through hole for a pawl clutch is continuous with the elongated groove. An output shaft flat plate clutch fixed to the other end surface of the shaft, a claw clutch which is slidably fitted in the long groove and has a switching cam portion which is provided on the outer peripheral surface so as to project in a direction orthogonal to the sliding direction, One end of this claw clutch is A claw clutch urging means disposed at the other end of the claw clutch so as to enter the mating groove side, and a convex portion or concave groove that is constantly fitted to the concave groove or convex portion of the output shaft are formed on the end surface. A fixed shaft; an output unit that is disposed between the fixed shaft and the output shaft and that biases the output shaft toward the input shaft flat plate clutch; The switching clutch and the switching cam portion to disengage the pawl clutch from the engaging groove against the pawl clutch urging means, and the output shaft flat plate clutch to the output shaft urging means. A stop lever having a plurality of stop pieces formed with an inclined surface for separating the input shaft flat plate clutch from the input shaft flat clutch is fitted in and fixed to the fixed shaft and an engaging and disengaging means provided so as to surround the output means. Is stretched at one end An operating means including an operating shaft rotatably fitted in the force shaft, an operating cam portion provided at the other end of the operating shaft, and a cloth presser lifting link that interlocks with the cloth presser according to the rotation of the operating cam portion. When the input means and the output means are disengaged, the switching cam portion and the flat plate clutch switching pawl are captured by the inclined surface formed on the stop piece, and the pawl clutch of the pawl clutch is operated. While the end part disengages from the engagement groove,
The output shaft plate clutch is separated from the input shaft plate clutch,
On the other hand, when the input means and the output means are connected, the switching cam portion and the switching clutch for the flat plate clutch captured on the inclined surface become free, and the output shaft flat plate clutch first comes into contact with the input shaft flat plate clutch by the output shaft biasing device. The output shaft flat plate clutch is rotated by friction while sliding on the surface of the input shaft flat plate clutch, and at the same time, the pawl clutch is biased toward the input shaft flat plate clutch by the pawl clutch biasing means, The end of the claw clutch rotates while sliding on the end surface of the input shaft, and when the mesh groove approaches, the claw clutch enters and meshes with the mesh groove. Therefore, since the flat plate clutch operates before the claw clutch meshes, and the meshing motion of the claw clutch becomes the meshing motion between the rotating bodies, it is possible to reduce the hitting sound. Further, since the function of the flat plate clutch is only before engaging the claw clutch, it is possible to greatly reduce wear and abnormal heat generation. Further, since the spring clutch is not used, there is no fear of chattering noise.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a presser foot lifting reducing device of a sewing machine according to an embodiment of the present invention.

FIG. 2 is an exploded perspective view of an input unit, an output unit, and an operation unit that form a drive unit.

3 is a view of the fitting / removing means as viewed from the X direction in FIG. 1. FIG.

FIG. 4 is a view for explaining a situation in which a switching claw for plate clutch and a switching cam portion are captured by a stop piece of the fitting / removing means.

5 is a view of the operating means and the operating means when viewed from the Y direction in FIG. 1. FIG.

FIG. 6 is a view of the reverse rotation preventing unit viewed from the X direction in FIG. 1.

[Explanation of symbols]

 1 Reduction pulley 6 Operation shaft 6a Operation cam portion 8 Input shaft 11 Claw clutch 11a One end of claw clutch 12 Engagement groove 15 Input shaft flat plate clutch 16 Long groove 17 Output shaft 18 Output shaft flat plate clutch 18a Through hole for claw clutch 20 Fixed shaft 21 Convex part of fixed shaft 22 Groove of output shaft 24,25 Stop lever 33,34 Stop piece 35 Switching cam part 36 Switching clutch for flat plate clutch 37 Claw urging means 39 Output shaft urging means 43 Cloth lifting bar A input means B output means C fitting / removing means D operating means E operating means

Claims (1)

[Claims] 1. A reduction pulley that is rotated by a motor, an input shaft integrally coupled to the reduction pulley, and having an end face formed with a mesh groove, and an input shaft flat plate clutch externally fitted and fixed to the input shaft. It has an input means, a flat plate clutch switching claw protrudingly provided on the outer peripheral surface, and a long groove formed along the axial direction of the outer peripheral surface. A movable output shaft, a through hole for a claw clutch is formed, and an output shaft flat plate clutch fixed to the other end surface of the output shaft at a position where the through hole for the claw clutch is continuous with the long groove, A pawl clutch that is movably loosely arranged and has a switching cam portion that is provided on the outer peripheral surface so as to project in a direction orthogonal to the sliding direction. One end of the pawl clutch enters the engagement groove side. The claw arranged at the other end of Urging means for the clutch, a fixed shaft having a convex portion or a concave groove formed on an end surface thereof, which is always fitted in the concave groove or the convex portion of the output shaft, the fixed shaft arranged between the fixed shaft and the output shaft, An output means for urging the shaft toward the input shaft flat plate clutch, and an output means comprising an output shaft urging means, and the flat plate clutch switching pawl and the switching cam portion on the inner side of the tip end to capture the pawl clutch with the pawl clutch. A sloping surface for separating the output shaft flat plate clutch from the input shaft flat plate clutch against the output shaft urging device while disengaging the output shaft flat plate clutch from the engagement groove against the output urging device. An operation in which a stop lever provided with a plurality of stop pieces is fitted and fixed to the fixed shaft and the fitting / removing means provided so as to surround the output means, and one end is extended and rotatably fitted to the input shaft. Axis, the other end of this operating axis Operating cam section provided, the more becomes the operating means, wherein in accordance with the rotation of the operating cam portion, sewing machine presser foot lifting relief device comprising comprising an operating means for operating the presser foot up link interlocked with the presser foot, the.