JP2743074B2 - Presser foot control device in sewing machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] Industrial Field of the Invention The present invention drives a presser foot separately from a needle bar,
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a presser foot control device for a sewing machine that prevents noise generated during high-speed driving and high-speed cycles.

2. Description of the Related Art Conventionally, as a needle bar and a presser foot mechanism in a sewing machine,
As shown in FIG. 10, a needle bar e having a needle fixing member d at its lower end is inserted into an upper support portion b and a lower support portion c of a needle bar case a in a vertically movable manner, and the needle bar e is spring-loaded. And a cloth holder g formed in a substantially self-shape is fitted in the lower part of the needle bar e so as to be movable up and down, and the cloth holder g is urged downward by a spring h to fabricate the cloth. An intermediate portion i of the presser g is elastically contacted with the needle fixing member d, and a member j such as a cushioning material and a dimension adjusting member is mounted on the upper surface of the lower support portion c.

When the needle bar e is reciprocated up and down by a predetermined stroke, the presser foot g also moves up and down accordingly. However, in such a state, the presser foot g moves halfway through the needle bar e to the bottom dead center. When the lower surface of the upper portion k of the upper surface collides with the member j, the bottom dead center of the presser foot g is regulated, whereby the lower end l of the presser foot g presses the upper surface of the cloth without abutting against a needle plate (not shown). It is made up of

In the above mechanism, when the needle bar e is driven, when the needle bar e descends, the lower surface of the upper part k of the presser foot g collides with the member j, so that a collision sound is generated at such a point, and the needle bar e When ascending, the needle fixing member d collides with the intermediate portion i of the presser foot g waiting at the bottom dead center position, so that a collision sound is generated as described above.

Such a collision sound has a disadvantage that when a large number of needle bars e are driven at a high speed and in a high cycle, the noise level becomes extremely high and the working environment is deteriorated.

Also, due to the above structure, when setting the bottom dead center position of the presser foot g, that is, the position where the cloth is pressed and supported by the lower end l of the presser foot g, or a cushioning material, a dimension adjusting member, etc. In addition, the replacement work of the member j is required, and the dimensional adjustment thereof is very difficult. Therefore, it has a drawback that it cannot cope with high-speed sewing and production of many kinds and small lots. .

Problem to be Solved by the Invention The present invention reduces the noise during high-speed driving and high-speed cycles by separately driving the presser foot with respect to the drive of the needle bar, and facilitates the adjustment of the bottom dead center position of the presser foot. The present invention is intended to provide a presser foot control device for a sewing machine which is capable of high-speed sewing and high-mix low-volume production.

[Configuration of the invention]

Means for Solving the Problems In view of such a point, the present invention has a sewing needle at a lower end, and a fitting head which is vertically movable on a needle bar which is reciprocally driven up and down, and is provided below the fitting head. A cloth presser is extended to form a cloth presser, and the fitting insertion head of the cloth presser is urged downward with respect to the needle bar by spring elasticity, and a stopper provided at a lower portion of the needle bar is formed. When the needle bar descends when the needle bar is lowered, sewing is performed by regulating the lower dead point of the presser foot descending with the needle bar by bringing the engaging portion provided on the presser foot into contact with the contact member. In a sewing machine that presses the upper surface of the cloth without bringing the cloth pressing portion of the cloth presser into contact with the needle plate at the time of inserting and removing the needle from the cloth,
The contact member is provided to be vertically movable, and the contact member is attached to an elevating member that is driven up and down in synchronization with the needle bar, and the elevating member is brought into contact with the engaging portion when the cloth presser is lowered. A reciprocating drive is performed between a lower limit position for regulating the bottom dead center of the presser foot by contact with the contact member and an upper limit position at a predetermined interval above the lower position. A configuration in which the abutment between the mating portion and the abutting member is relieved, and after the sewing needle is pulled out of the cloth, the lifting of the cloth presser is started before the stopper part comes into contact with the fitting insertion head, Further, the above-mentioned drawbacks can be solved by providing a presser foot control device for a sewing machine in which the abutment member is attached to the elevating member so that the upper and lower attachment positions can be finely adjusted.

According to the present invention, when the needle bar and the presser foot are lowered by the above configuration, the lower part of the insertion head of the presser foot is elastically contacted with the stopper portion of the lower part of the needle bar by spring elasticity. When the bar descends, the engaging portion of the presser foot abuts and engages with the contact member which is driven separately from the needle bar and descends during the stroke from the top dead center to the bottom dead center of the presser foot, and When ascending, after the sewing needle has been removed from the cloth, the contact member that is driven separately from the needle bar is raised first before the stopper portion contacts the fitting insertion head of the cloth presser, and the corresponding contact member The presser foot to be brought into contact with the head is raised in advance.

In addition, since the contact member is mounted so as to be vertically adjustable, the bottom dead center of the work clamp can be easily positioned.

An embodiment of the present invention will be described below with reference to the drawings. Reference numeral 1 denotes a head unit in a multi-head sewing machine, and the head unit 1 includes a driving unit 2 and a needle bar selecting unit 3.

First, the drive unit 2 will be described. Reference numeral 4 denotes a base frame fixed to a sewing machine frame 5. The base frame 4 is formed in a substantially rectangular frame shape having a front opening 6 and a top opening 7, and has both side walls. Through holes 8 and 8a near the middle of
Are concentrically provided, and a main shaft 9 whose rotation is appropriately controlled is rotatably supported by bearings or the like mounted in the through holes 8 and 8a.

Next, regarding the needle bar engagement mechanism 10 in the drive unit 2,
A base needle bar 11 is suspended vertically above and below the center of the front opening 6 of the base frame 4 (processing axis XX), and a needle bar engaging portion 12 is attached to the base needle bar 11.
Is mounted so as to be vertically movable, and is decentered by a predetermined amount with respect to the axis of the main shaft 9, that is, as shown in FIG. 9, the rotation time of the main shaft 9 (the time corresponding to the rotation angle) and the needle bar engaging portion 12 The disk cam mechanism 13 mounted with the eccentric amount to be formed with the cam diagram A drawn in relation to the predetermined stroke L1 (between the top dead center P1 and the bottom dead center P3 of the needle bar) The needle bar engaging portion 12 is connected to a needle bar engaging portion 12 via a link mechanism 15 having a support bar 14 disposed and fixed below the main shaft 9 as a fulcrum, and the needle bar engaging portion 12 is vertically reciprocated.

Reference numeral 16 denotes an engaging body that constitutes the needle bar engaging portion 12, and the engaging body
16 is provided with a spring receiving portion 18 protruding above and below the outer periphery of the cylindrical base portion 17 and forming a sliding contact surface 19 inclined downward at an upper portion of the outer peripheral position which is substantially 90 degrees in the circumferential direction from the spring receiving portion 18. Needle bar slide contact piece
20 and a projection 21 protrudes below the needle bar sliding contact piece 20 at a predetermined distance from the needle bar sliding contact piece 20 to form a fitting groove 22 between the needle bar sliding contact piece 20 and the projection piece 21. Further, a solenoid sliding contact piece 25 having a sliding contact surface 24 inclined downward at an outer peripheral position that is substantially 180 degrees in the circumferential direction from the spring receiving portion 18 is provided so as to serve as the engaging portion 23.

Reference numeral 26 denotes a support constituting the needle bar engaging portion 12, and the support
Reference numeral 26 denotes projecting support pieces 28 and 28a protruding from the upper and lower ends of a plate-like base 27, and through holes 29 and 29a formed concentrically in the support pieces 28 and 28a.

Then, the engaging body 16 is interposed between the supporting pieces 28 and 28a of the supporting body 26, and inserted into the through holes 29 and 29a and the cylindrical base 17 so as to project from the upper and lower ends of the cylindrical metal bush 30. The engaging body 16 is rotatable in the circumferential direction, and the coil portions 32 and 32a of the spring 31 are mounted on the upper and lower ends of the metal bush 30.
The intermediate portion 33 of the engaging member 16 is brought into contact with the spring receiving portion 18 of the engaging member 16 to urge the engaging member 16 in the clockwise direction.
The lower end of the support bar 28a is fixed to one side surface of the support bar 28a, and is brought into contact with one side surface of the protrusion 21 of the engagement body 16 to regulate the clockwise rotation of the engagement body 16 so that the needle bar engagement portion 12 is It is attached to the needle bar 11.

Next, with regard to the balance driving unit 35 of the driving unit 2, the shaft 36 is horizontally mounted at a position behind the upper surface opening 7 of the base frame 4, and a gear is
The base of the balance driving lever 38 with the attached 37 is rotatably mounted on the shaft 36, and the base of the arm 39 is rotatably mounted on the shaft 36 and integrally connected with the balance driving lever 38. A cam roller (not shown) attached to the cam 40 is fitted in a cam groove 41 of a cam 40 fixed to the main shaft 9, and the balance driving lever 38 is controlled to swing up and down in accordance with the rotation of the main shaft 9.

Next, with regard to the presser foot control mechanism 42 of the drive unit 2, a support shaft 43 is vertically extended over one side of the front opening 6 of the base frame 4, and the elevating member 44 is vertically movable on the support shaft 43. And a predetermined track, that is, as shown in FIG.
And a cam diagram B drawn based on the relationship between the rotation time (time corresponding to the rotation angle) and a predetermined stroke L2 of the lifting member 44 (between the top dead center P1 and the bottom dead center P2 of the work clamp). A cam 46 having a cam groove 5 engraved by a trajectory to be fixed is fixed to the main shaft 9 and is attached to a piece of an L-shaped arm 47 having the support rod 14 as a fulcrum in the cam groove 45 of the cam 46. A cam roller (not shown) is fitted, and the other end of the arm 47 is connected to the elevating member 44 via a lever 94 to reciprocate the elevating member 44 up and down.

The cam diagram B matches the top dead center P1 between the needle bar engaging portion 12 and the elevating member 44, and when descending, sets the delay time difference T1 at an arbitrary stroke position S to move the elevating member 44. The presser foot descends to the bottom dead center P2, and when it rises, the advance time difference T2 is set at an arbitrary stroke position S, and at least the top dead center P1 is appropriately reduced to raise the lifting member 44. It is a curve which rises to the dead point P1.

Further, the delay time difference T1 and the advance time difference T2 are set to zero,
That is, it is also possible to coincide when ascending and descending.

Next, as for the contact member 48 of the presser foot control mechanism 42, the lower end of the plate-like body 49 is bent forward, and the horizontal engaging piece 50 extending to the front portion of the base needle bar 11 is moved. Along with the formation, a long hole 51 is formed in the upper part in the vertical direction to form a contact member 48, and the corresponding contact member 48 is attached to the elevating member 44 by screws 52, 52a so that the upper and lower mounting positions can be finely adjusted. ing.

Reference numeral 53 denotes a balance guide to be mounted on the base frame 4 in front of the upper surface opening 7. The balance guide 53 is formed in an inverted T-shaped cross section and corresponds to a processing axis XX of the upright portion 54. Is cut out to form a cutout portion 55.

Reference numeral 56 denotes a solenoid. The solenoid 56 has a plunger 57 on one side wall of the base frame 4 and a plunger 57 of the solenoid 56 at a predetermined position with the sliding contact surface 24 of the solenoid sliding contact piece 25 of the engaging portion 23 when the solenoid 56 is operated. It is attached so that it touches.

In the figure, 58 is an arm rail mounted on the upper front surface of the base frame 4, 59 is a guide rail mounted on the lower front surface of the base frame 4, 60
Are guide rollers attached to the lower end of the base needle bar 11, 61, 61
a is a front cover.

Next, the needle bar selecting unit 3 will be described. Reference numeral 62 denotes a needle bar case. The needle bar case 62 forms vertical frames 63 and 63a in parallel at predetermined intervals, and the upper portions of the vertical frames 63 and 63a Extending rearward to form balance support portions 64, 64a, and integrally forming needle bar support portions 65, 65a at the lower and intermediate portions between the vertical frames 63, 63a, the needle bar support portions 6
The through-holes 66, 66a,...

Reference numeral 67 denotes a balance. The balance 67 is formed by forming a gear 69 on a part of the outer periphery of a cylindrical base 68 and mounting a gently curved support rod 70 between the needle bar support parts 65 and 65a. A large number are rotatably mounted on a balance shaft 71 which is horizontally mounted on the balance shaft 71.

72 is a cutout portion cut out at an appropriate position on the outer periphery of the base 68,
The notch portion 72 is formed so as to be loosely fitted and combined with the upright portion 54 of the balance guide 53.

73 is a needle bar, and the needle bar 73 has a spring fixing portion 74 detachably mounted on the upper end, and a needle fixing portion 75 mounted on the lower end,
Further, a needle bar dovetail portion 77 having a fitting piece 76 formed in a shape to be fitted into the fitting groove 22 of the needle bar engaging portion 12 is mounted at an intermediate portion.

Then, the needle bar 73 is turned into a pair of upper and lower through holes 66 of the balance case 62,
66a, a spring 78 is interposed between the spring locking portion 74 and the needle bar support portion 65 to urge the needle bar 73 upward, and a fitting insertion head 79 is formed in a substantially U-shape. At the same time, a cloth pressing portion 80 is extended downward from the fitting head 79 to form a cloth holder 81, and the fitting head is formed.
A needle bar 73 is inserted into a pair of upper and lower through-holes 82 and 82a of 79 to make the insertion head 79 freely movable up and down, and a spring 83 is interposed between the needle bar dovetail portion 77 and the insertion head 79. The stopper portion is the upper surface of the needle fixing portion 75 at the lower end of the needle bar 73 by urging the insertion head 79 downward.
The engaging piece of the contact member 48 is elastically contacted with
The engaging portion 85 extends rearward and is disposed at a position opposed to 50,
The engagement portion 85 and the engagement piece 50 can be brought into contact with each other at the time of driving up and down.

In the figure, reference numeral 86 denotes an arm rail mounted on the upper part of the balance case 62, 87 denotes a guide roller that slides on the lower surface of the arm rail 58, 88 denotes a guide that slides on the guide rail 59, and 89 denotes a needle bar.
A drive shaft for appropriately controlling the balance case 62 in the lateral direction when 73 is selected, a slide roller 90 interposed between the arm rail 58 and the arm rail 86, and a slide roller 91 interposed between the needle fixing portion 75 and the intermediate lower surface of the presser foot 80. A cushion material 92 to be mounted is a sewing needle fixed to the needle fixing portion 75.

Next, the operation of the presser foot driving device in the sewing machine according to the present invention will be described. First, when the needle bar 73 is driven, the needle bar case 62 is moved in the lateral direction by the drive shaft 89 so as to be in front of the base needle bar 11. At a corresponding position, an arbitrary needle bar 73 is disposed according to use, and a needle bar engaging portion 12 that has been previously stopped at an arbitrary stroke position, that is, at an appropriate position between the top dead center P1 and the bottom dead center P3. The needle bar 73 rises via the disc cam mechanism 13 and the link mechanism 15 by the rotation of the main shaft 9, and is urged upward by a spring 78 to stand by at the top dead center P 1. The engagement piece 76 is pressed and slidably contacted with the sliding surface 19 of the needle bar sliding contact piece 20 of the engagement body 16, and the engagement action causes the engagement body 16 to move counterclockwise against the elastic force of the spring 31. By the rotation, the fitting piece 76 is engaged in the fitting groove 22 of the engaging portion 23.

After the engagement, the engagement body 16 is rotated clockwise by the elastic force of the spring 31 and returned to the initial state.

When the needle bar 73 is arranged as described above, the balance driving lever
The gear 37 of 38 and the gear 69 of the balance 67 are engaged with each other,
With the rotation of, the support rod 70 of the balance 67 is controlled to swing through the cam 40, the arm 39, and the balance drive lever 38.

In such a state, the balance 67 is notched in the balance guide 53.
By being placed in the position 55, the engagement with the balance guide 53 is released.

Next, when lowering the needle bar 73 and the work clamp 81,
The lower portion of the needle fixing portion 79 of the presser foot 81 is elastically contacted with the stopper portion 84 of the needle fixing portion 75 at the lower end of the 73 by the elastic force of the spring 83. Joint 12
The needle bar 73 connected to the lower portion of the cam member A moves along the locus of the cam diagram A, and accordingly, the engaging piece 50 of the contact member 48 connected to the elevating member 44 which moves down the locus of the cam diagram B. On the top of
The engaging portion 85 of the fitting insertion head 79 of the cloth presser 81 is previously engaged and engaged, and in this state, the lowering of the fitting insertion head 79 is regulated, and the engagement state is maintained until the bottom dead center P2. By lowering the insertion head 79, the presser foot 81 is lowered.

In this state, since the contact member 48 is lowered with the delay time difference T1, the lower portion of the fitting head 79 and the needle fixing portion
The presser foot 81 descends to the bottom dead center P2 while maintaining a gap corresponding to the delay time difference T1 between the stopper member 84 and the stopper portion 84, and at the time of ascending, the contact member 48 is moved along the locus of the cam diagram B. , The needle bar 73 is first raised along the trajectory of the cam diagram A. At least when the needle bar 73 reaches the top dead center P1, the advance time difference T2 between the needle bar 73 and the work clamp 81 is increased. And the presser foot 81 is raised so as to coincide at the top dead center P1.

In such a state, since the advance time difference T2 is sequentially reduced, the lower portion of the fitting head 79 and the stopper 84
And the gap corresponding to the time difference T2 gradually decreases, that is, at least reaches the top dead center P1, the speed difference between the needle bar 73 and the presser foot 81 decreases and increases.

It should be noted that the needle bar 73 and the work clamp 81 can be controlled to move up and down without any time difference when ascending and descending.

Further, in the present embodiment, when the presser foot 81 is at the top dead center P1, the contact member 48 is moved to a position where the engaging piece 50 of the contact member 48 comes into contact with the lower surface of the engaging portion 85 of the presser foot 81. Although the contact member 48 is driven, it is not always necessary to move the contact member 48 up to this position. In this case, the stroke of the contact member 48 can be reduced, and This has the advantage that vibrations can be suppressed.

Further, since the contact member 48 is attached to the elevating member 44 so as to be vertically adjustable, the positioning of the bottom dead center P2 of the presser foot 81 can be facilitated.

〔The invention's effect〕

In short, the present invention has a sewing needle 92 at a lower end, and a fitting insertion head 79 is fitted to a needle bar 73 reciprocally driven up and down so as to be vertically movable, and a cloth pressing portion 80 is provided below the fitting head 79. To extend the presser foot
81, the insertion head 79 of the presser foot 81 is urged downward with respect to the needle bar 73 by spring elasticity, and is elastically contacted with a stopper portion 84 provided below the needle bar 73. When the needle bar 73 descends, the lower dead point P2 of the work clamp 81
By regulating the engaging portion 85 provided on the cloth presser 81 by abutting the contact member 48, the cloth pressing section 80 of the cloth presser 81 can be moved when the sewing needle 92 is inserted into and removed from the cloth W. In a sewing machine that presses the upper surface of the cloth W without contacting the needle plate 93, the contact member 48 is provided so as to be vertically movable, and the contact member is moved up and down in synchronization with the needle bar. The lifting member is spaced from the lower limit position for regulating the bottom dead center of the presser foot by contact between the engaging portion and the contact member when the presser foot is lowered, and a predetermined interval above the lower limit position. It reciprocates between the upper limit position and reduces the collision between the engaging part and the contact member when regulating the bottom dead center of the presser foot.
Loud collision sound can be prevented from being generated when the pressure reaches the threshold value, and the noise when descending can be reduced.

Further, after the sewing needle 92 is pulled out from the cloth W, the cloth pusher 81 starts to rise before the stopper portion 84 comes into contact with the fitting head 79. Of the needle fixing member d is prevented from contacting the intermediate portion i of the presser foot g with a large impact force, and the noise during the ascent can be reduced.

Therefore, the noise generated at high speed and high cycle can be reduced, so that the working environment can be improved, and the lifting and lowering control can be performed at high speed and high cycle to eliminate the need.

Also, since the contact member 48 is attached to the elevating member 44 so that the upper and lower attachment positions can be finely adjusted, the cloth pressing portion of the cloth presser 81 can be adjusted.
The positioning of the bottom dead center P2 of 80 can be easily performed, thereby enabling a wide variety of small lots to be produced for fabrics W having various thicknesses. It becomes.

[Brief description of the drawings]

FIG. 1 shows an embodiment of the present invention. FIG. 1 is a longitudinal sectional view of a head portion of a presser foot control device in a sewing machine according to the present invention. FIG. 3 is a front view of the same drive unit, FIG. 4 is a front view of the same needle bar selection unit, FIG. 5 is a schematic plan view of the same head unit, FIG. 6 is a perspective view of the same base frame, and FIG. Is a perspective view of the needle bar case, FIG. 8 is an exploded perspective view of the needle bar engaging portion, FIG. 9 is a cam diagram, and FIG. 10 is a schematic sectional view of a conventional needle bar driving device. 48 abutment member, 73 needle bar 79 insertion head, 80 cloth pressing part 81 cloth presser, 84 stopper part 85 engagement piece, 92 sewing needle

Claims (2)

(57) [Claims] A sewing needle is provided at a lower end, and a fitting head is vertically movably fitted to a needle bar which is reciprocally driven up and down, and a cloth pressing portion is extended below the fitting head to extend the cloth. A presser is formed, and the insertion head of the cloth presser is urged downward with respect to the needle bar by a spring elasticity, and is elastically contacted with a stopper provided at a lower portion of the needle bar,
When the needle bar is lowered, the lower dead center of the presser foot that is lowered with the needle bar is regulated by bringing the engaging portion provided on the presser foot into contact with the abutting member, so that the lower part of the needle foot can be moved to the sewing needle cloth. At the time of needle insertion and needle removal, in a sewing machine that presses the upper surface of the cloth without bringing the cloth pressing portion of the cloth presser into contact with the needle plate, the contact member is provided to be vertically movable, and the corresponding contact member is A lower limit for controlling the lower dead center of the presser foot by contacting the engaging portion and the contact member when the presser foot is lowered, the lower presser being attached to an elevating member that is driven up and down in synchronization with the needle bar; It reciprocates between the position and the upper limit position at a predetermined interval above the position to relieve the contact between the engaging portion and the abutting member when regulating the bottom dead center of the presser foot, and the sewing needle After removing the needle from the cloth, the lifting of the cloth presser is started before the stopper part comes into contact with the fitting head. Presser controller device in a sewing machine, wherein the door. 2. The presser foot control device for a sewing machine according to claim 1, wherein said contact member is attached to said elevating member so that an upper and lower attachment position can be finely adjusted.