JPH04295395A - Device for pressing cloth for use in blind stitching sewing machine - Google Patents

Abstract

PURPOSE:To enable reduction in the range of fluctuation of a force exerted by a spring mechanism to push a plunger and also to enable the pushing force to be readily and accurately adjusted. CONSTITUTION:A bearing member 4 is vertically rotatably mounted to a fixed shaft 2 provided to a frame and the rotary shaft 6 of a plunger 8 is axially supported to the bearing member 4 in such a manner as being freely rotated in its circumferential direction. One end of a turning lever 30 is connected to the free end of the bearing member 4 via a universal joint 32. A spring mechanism 54 comprising a link 38, a bell rank 44 and a pushing spring 48, etc., is connected to the other end of the turning lever 30. A fulcrum member 34 is mounted on the frame in such a manner as being freely moved in the direction of the axis of the turning lever 30, and the fulcrum member 34 is fixed to the frame by a handle 36. The turning lever 30 is put in a turning movement about the fulcrum member 34 by the pushing force of the spring mechanism 54 and raises the plunger 8. The force exerted by the pushing spring 48 to push the plunger is varied by changing the position of the fulcrum member 34.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressing device for intermittently pressing cloth against a presser foot in synchronization with the operation of a scoop needle in a lockstitch or chain stitch blindstitch sewing machine.

0002

[Prior Art] As a cloth pressing device in a blind stitch sewing machine, a rotating shaft that can be rotated back and forth in the circumferential direction at a predetermined angle is almost horizontally supported on a bearing member attached to a frame so as to be movable up and down. A plunger (cloth lifter) that rotates in the circumferential direction together with the rotating shaft to press the cloth against the presser foot is attached to one end of the rotating shaft, and a plunger (fabric lifter) is attached to one end of the rotating shaft to press the cloth against the presser foot. It is known that an urging spring is provided between the bearing member and the plunger to move the bearing member upward and urge the plunger to approach the presser foot (Japanese Patent Publication No. 60-3
2464).

[0003] This pressing device moves between the presser foot and the plunger a portion where many layers of cloth are overlapped and the thickness is large, such as the seamed portion of the folded part of the hem of pants. When the cloth thickness increases, the bearing member flexes the biasing spring and moves downward, lowering the plunger by an amount corresponding to the increase in cloth thickness. Adjust the elasticity of the biasing spring using the adjustment screw.

0004

[Problems to be Solved by the Invention] In the above-mentioned conventional cloth pressing device, a short biasing spring is used, so when the thickness of the fabric changes, the elasticity of the biasing spring changes greatly, resulting in blind stitching. There will be negative effects. In addition, the number of layers of fabric in the seamed part of the folded part of the pants hem is usually 4, but if this part is further folded back and stitched so that the thread is finally hidden, the seamed part becomes 3 layers. Since they overlap, the number of stacked sheets is six.

In theory, it is possible to solve the above problem by using a long biasing spring, but if the biasing spring is long, the elasticity adjustment range becomes too large, and the elasticity can be adjusted within one rotation. It is preferable to perform the adjustment operation as follows: It is necessary to turn the adjustment screw many times, making the adjustment extremely troublesome. As a result, in the configuration of the conventional pressing device, it is not possible to obtain a cloth pressing device in which the plunger biasing force has a small fluctuation range and the biasing force can be easily adjusted by simply changing the length of the biasing spring.

SUMMARY OF THE INVENTION An object of the present invention is to provide a cloth pressing device for a blind stitch sewing machine that can reduce the variation range of plunger biasing force and can easily and accurately adjust the biasing force. .

[0007] In order to achieve the above object, the present invention
A rotating shaft that reciprocates in the circumferential direction at a predetermined angle is supported by a bearing member movably attached to the frame with its axial direction substantially perpendicular to the moving direction of the bearing member. In a cloth pressing device for a blindstitch sewing machine, in which a plunger is attached to one end of the plunger that rotates in the circumferential direction together with a rotation shaft to press the cloth against the presser foot, the plunger is attached to the bearing member and rotates about the fulcrum member. A spring mechanism mainly consisting of a biasing spring connected to one end of a rotary lever, which rotates the rotary lever about a fulcrum member so that the plunger approaches the presser foot when the bearing member moves. and the fulcrum member is movable relative to the spring mechanism in the axial direction of the rotating lever.

[0008]

[Operation] By moving the fulcrum member relative to the spring mechanism and increasing the ratio of the distance between the fulcrum member and the spring mechanism to the distance between the fulcrum member and the plunger, the plunger biasing force of the spring mechanism increases, Furthermore, if the above ratio is made smaller, the plunger biasing force becomes smaller.

[0009] If a long biasing spring is used in the spring mechanism, the variation range of the plunger biasing force due to changes in fabric thickness will be reduced, but even in this case, it is not possible to easily and accurately adjust the plunger biasing force. can.

0010

[Embodiment] The attached drawings show an embodiment of the present invention.
Reference numeral 1 in the figure is a frame. A pair of upper and lower fixed shafts 2 and 3 are provided on the frame 1 horizontally and parallel to each other at a predetermined interval. Bearing members 4 and 5 are individually supported on each of the fixed shafts 2 and 3. Each bearing member 4, 5 is vertically rotatable about each fixed shaft 2, 3.

A rotation shaft 6 is attached to the free end of each bearing member 4, 5.
, 7 are individually supported. Each rotating shaft 6, 7 is provided parallel to each fixed shaft 2, 3. Fan-shaped plungers 8 and 9 are individually fixed to the left end of each rotation shaft 6 and 7 in FIG. 1 . Each plunger 8, 9 rotates alternately in the circumferential direction together with each rotating shaft 6, 7, and presses the cloth against a cloth presser foot (not shown).

Further, a pair of upper and lower drive shafts 12 are mounted on the bearings 10 and 11 provided on the right side of the frame 1 in FIG.
, 13 are supported with the same vertical spacing as the fixed shafts 2 and 3, and with their axial directions aligned parallel to the axial directions of the fixed shafts 2 and 3. Each drive shaft 12, 13 has a rotation shaft 6,
7, and is provided almost on an extension line thereof.

Drive arms 16 and 17 each having sliders 14 and 15 rotatably provided at their tips are individually fixed to the ends of each of the drive shafts 12 and 13 on the respective rotating shafts 6 and 7 side. . Driven arms 18 and 19 having sliding grooves 18a and 19a are individually fixed to the ends of the rotating shafts 6 and 7 on the side of the driving shafts 12 and 13.
Each slider 14, 15 of No. 6, 17 is slidably fitted therein.

Therefore, when each drive shaft 12, 13 rotates in the circumferential direction, the rotation is transmitted to each rotation shaft 6, 13 via drive arms 16, 17, sliders 14, 15, and driven arms 18, 19. 7, and each rotating shaft 6, 7 rotates in the circumferential direction. When the rotation shafts 6, 7 move relative to the drive shafts 12, 13, the sliders 14, 15 slide on the respective sliding grooves 18a, 19a and rotate the respective driven arms 18, 1.
9.

Gears 20 and 21 are individually fixed to each drive shaft 12 and 13 and are meshed with each other. The gear 21 of the lower drive shaft 13 is larger than the gear 20 of the upper drive shaft 12, and the upper plunger 8 has a smaller turning radius.
The rotation width of the peripheral edge of the plunger 9 and the peripheral edge of the lower plunger 9, which has a large rotation radius, are approximately the same. A gear 22 having the same diameter as the gear 20 is loosely attached to the upper drive shaft 12,
This is also meshed with the gear 21. The gear 22 is fixed by a set screw (not shown) to prevent backlash of the gear 21.

A swing lever 23 is fixed to the lower drive shaft 13. One end of a swing arm 24 is connected to the tip of the swing lever 23 with a pin 25. Swing arm 2
A round hole 24a is formed at the other end of 4. An eccentric ring 27 of a rotating shaft 26 rotated by a drive device (not shown) is fitted into the round hole 24a.

At the free end of each bearing member 4, 5, one end of a rotating lever 30, 31 is connected to a universal joint 32, 33 such as a ball joint.
are individually connected via. Each rotating lever 30, 3
1 is individually supported at its intermediate portion by fulcrum members 34 and 35. Each fulcrum member 34, 35 has a rotation stopper 3
4a, 35a and screw portions 34b, 35b are integrally provided, and each rotation stopper 34 is provided in the elongated hole 1a, 1b formed in the frame 1.
a, 35a to make each threaded part 34b, 35b protrude from the front of frame 1 (right side in FIG. 6), and screw knobs 36, 37 into each threaded part 34b, 35b individually to attach frame 1. installed. Each rotation stop 34
a, 35a are formed into elongated shapes, and each fulcrum member 34, 35
This prevents free rotation and allows free movement along the elongated holes 1a and 1b.

The upper ends of links 38 and 39 are individually connected to the other end of each rotating lever 30 and 31 by universal joints 40 and 41 such as ball joints. The lower end of each link 38, 39 is connected to a bell crank 44, 45 by a universal joint 42, 43 such as a ball joint.
are individually connected to one end of the Each bell crank 44,
45 is rotatably attached to another frame 28 by pivots 46, 47, and has biasing springs 48, 49 at the other end.
One end of each is connected individually. Each biasing spring 48, 49
The other ends are individually connected to threaded rods 50, 51, and each threaded rod 50, 51 is connected to an adjustment nut 52, which is provided on the frame 1.
53 are individually screwed into the holes.

[0019] Biasing springs 48, 49 and bell crank 44,
45 and the links 38, 39, etc. are each a spring mechanism 54.
, 55. Each spring mechanism 54, 55 rotates each rotating lever 30, 31 about the fulcrum member 34, 35, and urges the plunger 8, 9 to rise.

Presser feet 56 are provided on the left and right sides of the plungers 8 and 9 in FIG. The presser foot 56 is attached by a pin 59 to the upper end of a presser lever 58, which is attached to the frame 1 so as to be pivotable up and down about a mounting shaft 57 (FIG. 3). Presser foot lever 58
is urged upward by a coil spring 61 so as to come into contact with a screw shaft 60 screwed onto the frame 1 and stop. A feed dog (not shown) is provided above the presser foot 56 to feed the cloth by circulating it in a vertical plane. The feed dog and the presser foot provided above the plungers 8 and 9 are well known.

Next, the operation of the cloth pressing device in the blind stitch sewing machine according to the present invention constructed as described above will be explained. When the eccentric wheel 27 is rotated by the rotary shaft 26, the swing arm 24 swings left and right in FIG. 2, causing the drive shaft 13 to reciprocate in the circumferential direction at a predetermined angle.

The above rotation of the drive shaft 13 is transmitted to the rotation shaft 7 via the drive arm 17 etc. on the one hand, and is transmitted to the rotation shaft 7 via the gears 21, 20 and the drive arm 16 etc. on the other hand. 6 can be conveyed. The plungers 8, 9 attached to the respective rotation shafts 6, 7 are rotated in opposite directions due to the above-mentioned rotation of the rotation shafts 6, 7, and alternately push up the cloth in a well-known manner.

When the thickness of the fabric to be stitched is thick, each plunger 8, 9 automatically descends against the elasticity of the biasing springs 48, 49, causing the stitches to be sewn on the front surface and the needle Prevent problems such as bending. When it is desired to increase the plunger biasing force of each biasing spring 48, 49, the knobs 36, 37 are loosened, the fulcrum members 34, 35 are moved to the left in FIG. 1, and the knobs 36, 37 are tightened. This operation increases the ratio of the distance between the fulcrum members 34, 35 and the universal joints 40, 41 to the distance between the fulcrum members 34, 35 and the plungers 8, 9, so that the plunger attachment of each biasing spring 48, 49 The power becomes stronger. It goes without saying that if the fulcrum members 34, 35 are moved to the right in FIG. 1, the elasticity of the biasing springs 48, 49 will be weakened.

In addition to the above, the elasticity of the biasing springs 48 and 49 can be adjusted by operating the adjustment nuts 52 and 53 to change the tension of the biasing springs 48 and 49, but this is normally done when assembling the sewing machine. Only.

Examples other than the above will be listed below. (1) In the illustrated embodiment, the fulcrum members 34 and 35 are moved along the rotating levers 30 and 31, but the same purpose and effect as above can be achieved by moving the spring mechanisms 54 and 55. be able to.

(2) The fulcrum members 34, 35 are provided at the ends of the pivoting lever 30.31, and the spring mechanisms 54, 55 are attached to the pivoting lever 30.31 between the fulcrum members 34, 35 and the plungers 8, 9. It is also possible to apply a biasing force of . Also in this case, the fulcrum members 34, 35 and the spring mechanism 5
Either of 4 and 55 may be movable.

(3) The bearing members 4 and 5 shown in the figure are configured to rotate up and down around the fixed shafts 2 and 3;
The present invention can also be applied to a sewing machine in which one or both of the bearing member and the rotating shafts 4 and 5 move up and down along a guide member (for example, the sewing machine disclosed in Japanese Patent Publication No. 60-32464).

[0028]

Effects of the Invention As explained above, the cloth pressing device in the blind stitch sewing machine according to the present invention has a rotating mechanism that reciprocates in the circumferential direction at a predetermined angle on a bearing member movably attached to the frame. A shaft is supported with its axial direction substantially perpendicular to the moving direction of the bearing member, and a plunger is attached to one end of the rotating shaft to rotate in the circumferential direction together with the rotating shaft to press the cloth against the presser foot. In a cloth pressing device for a blind stitch sewing machine, one end of a rotary lever that rotates about a fulcrum member is connected to the bearing member, and the plunger is connected to the cloth by movement of the bearing member. A spring mechanism mainly consisting of a biasing spring that rotates the rotary lever about the fulcrum member so as to approach the presser foot is connected, and the fulcrum member is rotated relative to the spring mechanism in the axial direction of the rotary lever. Since it is configured to be relatively movable, it is possible to reduce the fluctuation range of the plunger biasing force due to the spring mechanism, and the biasing force can be adjusted easily and accurately.

[Brief explanation of drawings]

FIG. 1 is a front view showing an embodiment of a cloth pressing device in a blind stitch sewing machine according to the present invention.

FIG. 2 is a front view showing the relationship between a bearing member, a spring mechanism, etc.

FIG. 3 is a front view showing the relationship between the bearing member, the plunger, etc.

FIG. 4 is an external view showing the relationship between the rotating lever, the bearing member, the spring mechanism, etc.

FIG. 5 is a front view showing the relationship between the driven arm and the slider.

FIG. 6 is a sectional view showing how the fulcrum member is attached to the frame.

[Explanation of symbols]

1 Frame 4, 5 Bearing member 6,7 Rotation axis 8,9 Plunger 34, 35 Fulcrum member 38, 39 Link 44,45 Bell rank 48, 49 Biasing spring 54, 55 Spring mechanism

Claims (1)

[Claims] 1. A rotating shaft that reciprocates in the circumferential direction at a predetermined angle is supported by a bearing member movably attached to a frame with its axial direction substantially perpendicular to the moving direction of the bearing member, In a fabric pressing device for a blind stitch sewing machine, a plunger is attached to one end of the rotating shaft to rotate in the circumferential direction together with the rotating shaft to press the fabric against a presser foot,
One end of a rotating lever that rotates about the fulcrum member is connected to the bearing member, and the rotating lever is connected to the fulcrum member so that the plunger approaches the presser foot when the bearing member moves. A spring mechanism mainly consisting of a biasing spring that rotates the fulcrum member is connected to the fulcrum member, and the fulcrum member is
A cloth pressing device for a blind stitch sewing machine, characterized in that the cloth pressing device is provided to be movable relative to the spring mechanism in the axial direction of a rotating lever.