JPH04156883A - Fabric feed device for sewing machine - Google Patents

Abstract

PURPOSE:To dispense with the protruded quantity adjusting work of a feed dog by an operator by providing a control means controlling the drive source of a vertical movement system to adjust the protruded quantity of the feed dog above a throat plate based on the detection value obtained by a detecting means. CONSTITUTION:A detecting means detecting the height position of a presser foot changed in response to the thickness size of a work fabric and a control means controlling the drive source of a vertical movement system 72 to adjust the protruded quantity of a feed dog 36 above a throat plate 34 based on the detection value obtained by the detecting means are provided. When the vertical movement motor 72 is controlled by the control device, the sway angle of a vertical arm 68 is adjusted, and the protruded quantity of the feed dog 36 from the throat plate 34 can be adjusted. When the work fabric mounted on a bed section is pinched between the presser foot and the throat plate, the fabric thickness of the work fabric is detected, and the protruded quantity of the feed dog 36 from the upper face of the throat plate 34 is automatically set to a proper value based on the detection value.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a cloth feeding device for a sewing machine, and more particularly, it is possible to determine the amount by which a feed dog of a workpiece cloth protrudes from the upper surface of the throat plate depending on the thickness of the workpiece cloth. The present invention relates to a cloth feeding device that can be automatically adjusted according to the requirements and can always achieve smooth transfer of workpiece cloth.

Prior Art Sewing machines that perform straight stitches, zigzag stitches, and various other pattern stitches have a needle bar equipped with a sewing needle that swings at a required angle as necessary during sewing operation, and also has a needle bar that can move up and down and move back and forth on the throat plate. The machine applies the necessary feeding motion to the work cloth on the bed by the facing feeder, and sews straight lines and various other characters and patterns on the work cloth.

As shown in FIG.
0 point position), it moves up and down between a top dead center position hl located above the 0 point position and a bottom dead center position hb located below. When the feed dog reaches the top dead center position h1, it is moved forward to transfer the work cloth, and when the feed dog reaches the bottom dead center position hb, it is moved backward. That is, the feed warehouse transports the work cloth by performing four-directional vertical movement.

By the way, ordinary sewing machines can sew various types of processed fabrics, from ordinary thin fabrics to fabrics as thick as 6 mm. At this time, when sewing work cloths with different seasons without changing the amount of protrusion of the feed dog from the top surface of the throat plate (height dimension from the 0 point position to the top dead center position [hl), it is possible to There are problems such as insufficient feed and sewing shrinkage. For example, when sewing a thin work cloth, it is better to set the protrusion amount of the bacteria to be small, but if a thick work cloth is sewn in this state, insufficient feed will occur. On the other hand, when sewing thick work cloth, it is better to set the protrusion amount before feeding to a large value, but if sewing thin work cloth in this state, sewing shrinkage will occur.

Therefore, as a conventional technique, a switching knob or the like for switching the amount of protrusion before feeding is provided in the vertical movement mechanism that gives vertical movement to the feed dog, and the operator operates the switching knob depending on the thickness of the work cloth. There is a sewing machine in which the amount of protrusion of the feed pin from the upper surface of the throat plate can be changed.

Problems to be Solved by the Invention In most cases, the switching knob for switching the protrusion amount of the send-off message is located inside the bed of the sewing machine.
When operating the switching knob, the lid disposed on the bed was removed and a screwdriver or finger was inserted through the opening. The work of changing the overhang amount before feeding in this way is
This method relies on the manual labor of the operator and has the disadvantage of being extremely complicated since the work must be done in a confined space.

There are also sewing machines with a switching knob located outside the bed, but regardless of the type, the operator is the one who operates the switching knob when sewing, so if the operator makes an operational error, the fabric may be damaged. Frequently, the feeding condition deteriorates.

Purpose of the Invention The present invention has been proposed in view of the above-mentioned problems and to suitably solve the problems. can be adjusted to
It is an object of the present invention to provide a means that can eliminate the need for an operator to adjust the amount of protrusion of a feeder.

Means for Solving the Problems In order to overcome the above problems and achieve the intended purpose, the present invention provides a presser foot that is movably disposed above the throat plate on which the work cloth is placed, and a In a sewing machine, the sewing machine is equipped with a feed shaft located facing a slit drilled in the feed shaft, a vertical movement mechanism that provides vertical movement to the feed shaft, and a back and forth movement mechanism that provides longitudinal movement to the feed container, the vertical movement of the feed container being a dedicated drive source that independently drives the mechanism; a detection device that detects the height position of the presser foot that changes depending on the thickness of the work cloth; The present invention is characterized by comprising a control means for controlling the drive source of the vertical movement mechanism to adjust the amount by which the feeding ring protrudes above the throat plate.

According to the present invention, when the work cloth placed on the bed portion is pressed between the presser foot and the throat plate, the seasonality of the work cloth is detected;
Based on this detected value, the amount of protrusion of the feed dog from the upper surface of the throat plate is automatically set to an appropriate value.

Embodiment Next, a preferred embodiment of the cloth feeding device for a sewing machine according to the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a schematic configuration diagram showing a sewing machine 10 according to an embodiment with a cover 11 removed from a head 24 of the sewing machine 10. As shown in FIG. The main body of the sewing machine 10 includes a pattern display section 14 that displays patterns stored in a ROM 12, which will be described later, and a pattern selection operation section 16 that includes known operation switches for selecting these patterns.
and a display section 18 made of liquid crystal that displays the selected pattern etc. for confirmation. Further, a start/stop switch 26 for controlling starting/stopping of a sewing machine motor 82 (see FIG. 6) is provided on the sewing machine head 24.

(About the basic structure of the sewing machine) A needle bar base 1 is attached to the fixing protrusion 13 provided on the upper part of the head 24.
5 is pivotally supported via a shaft 17 and can swing within a required angle in a vertical plane. The lower part of the needle bar stand 5 is connected to a connecting rod 21 by a shaft 19, and this connecting rod 21 is driven and connected to a needle bar swing control motor 89 shown in FIG. The table 15 is given a swing within a required angle.

A needle bar 30 is attached to the needle bar stand 15 so as to be able to slide up and down, and a sewing needle 28 is fixed to the lower end of the needle bar 30. This needle bar 30 is connected to a sewing machine motor 82 shown in FIG. 6 via a needle bar holder 23 provided thereon and a main shaft (not shown). By driving the sewing machine motor 82, the needle bar 30 and the sewing needle 28 are given vertical reciprocating motion.

A throat plate 34 is provided in the bed portion 32 of the sewing machine 10, and a feeder 36 faces upwardly into a plurality of rows of slits 34a formed in the throat plate 34 (see FIG. 5). This feed 1 #36 is transferred to the sixth feed through a feed mechanism 38, which will be described later.
A motor 64 for longitudinal movement and a motor 72 for vertical movement shown in the figure.
The motors 64 and 72 drive the front and rear
A feed motion in the vertical direction (with respect to the sewing machine operator) is provided.

Further, as shown in FIG. 1, a presser bar 27 is fitted into a protrusion 25 provided at a fixed position above the feed dog 36 so as to be movable up and down.
A presser foot 29 is attached to the lower end of this presser bar 27 via a holder 31.

Furthermore, the presser bar 27 is always pressed downward by a presser spring (not shown), and the presser bar holder 3 fixed thereto
3, the presser foot lifter 37 moves the presser foot up and down.

Further, in FIG. 1, reference numeral 39 indicates a seasonal detector consisting of, for example, a potentiometer, and the movable lever 4 of the detector 39
1 is urged to rotate clockwise by a tension spring 43,
It resiliently contacts the presser bar holder 33 via a pin 45. Therefore, the height position of the presser foot 27, in other words, the thickness of the work cloth 35 pressed between the presser foot 29 and the throat plate 34,
It will be read by the seasonal detector 39.

(About the feeding mechanism of the feed dog) The feed dog 3 facing the slit 34a formed in the throat plate 34
6 is a feed mechanism 38 that operates approximately in synchronization with the needle bar 30;
It is connected to the. As shown in FIG.
It basically consists of a back-and-forth movement mechanism 42 that gives horizontal back-and-forth movement to the feeder 6, and a vertical movement mechanism 44 that gives up and down movement to the feeder 36.

(Regarding the forward and backward movement mechanism) A board 50 is provided horizontally inside the bed portion 32,
The feed table 40 is disposed on the substrate 50 so as to be movable back and forth and up and down by a mechanism to be described later. That is, as shown in FIGS. 2 and 4, the feed table 40 is formed in an inverted U-shape, and the feed dog 36 is fixed to the upper surface of the upper horizontal portion 40a with a screw 46. Also, feed stand 4
The lower horizontal part 40b of 0 is formed with an overhanging part 40c that extends horizontally on the front side (the side facing the operator), and a long hole 48 in the front-rear direction is bored in this overhanging part 40c. . A guide bin 52 vertically protruding from the base plate 50 slidably faces the elongated hole 48, and when the back-and-forth movement mechanism 42 operates, the feed bar 40 acts as a guide for the bin 52 facing the elongated hole 48. It is configured to move back and forth in a straight line.

As shown in FIG. 3, a pivot pin 56 is erected on the base plate 50 at a position close to the feed table 40, and a horizontal arm 54 is pivotally supported on the pin 56 so as to be freely rotatable in the horizontal direction. This horizontal arm 54 consists of a first arm part 54a and a second arm part 54b, each extending in opposite directions about the pivot point. The first arm portion 54a is connected to the feed base 40
The distal end thereof faces between the upper horizontal portion 40a and the lower horizontal portion 40b of the feed table 40. Further, a shaft 58 projecting in the vertical direction is vertically fixed to the tip of the first arm portion 54a, and the upper and lower ends of this shaft 58 are connected to the corresponding upper and lower horizontal portions 40a,
It is slidably inserted into a through hole bored in 40b.

Note that the upper end of the shaft 58 is connected to the feed dog 36 fixed to the feed base 40.
It is also commonly inserted through the through hole drilled in the.

Further, the lower horizontal portion 40b of the feed table 40 and the first arm portion 5
As shown in FIG. 4, a compression spring 60 wound around the shaft 58 is elastically interposed between the shaft 58 and the shaft 58. Therefore, the feed bar 40 is always urged downward under the elastic action of the compression spring 60, and the lower surface of the overhang 40c is brought into contact with a contact member 67 provided on a vertical arm 68, which will be described later. ing.

The second arm portion 54b extends in a direction away from the feed base 40, and has a sector gear 62 integrally formed at its tip, as shown in FIG. This sector gear 62 is a motor 6 for longitudinal movement arranged vertically on the board 50.
It meshes with the pinion 66 of No. 4. Therefore, by driving the forward and backward movement motor 64, the horizontal arm 54 rotates about the pivot pin 56, and moves the feed base 40 and the feed weight 36, which are supported on the first arm portion 54a via the shaft 58, forward. and horizontally driven backwards. As mentioned above, the elongated hole 4 of the overhanging portion 40c of the feed base 40
A guide pin 52 protruding from the base plate 50 is inserted through the guide pin 8, so that the feed table 40 is guided by the guide pin 52 and moves linearly back and forth.

(Regarding the Vertical Movement Mechanism) As shown in FIGS. 2 and 4, a support piece 71 is provided at an appropriate position on the board 50, that is, at a position close to the overhanging part 40c of the feed table 40. A vertical arm 68 is rotatably supported in the vertical direction by a pivot pin 69 pushed laterally. The vertical arm 68 has a first arm portion 68g and a second arm portion 68b extending in opposite directions from each other about the pivot portion thereof. The first arm portion 68a extends toward the feed table 40 from the pivot portion as a base point, and has its tip facing below the projecting portion 40c of the feed table 40.

The projecting portion 40c is biased downward under the elastic action of the compression spring 60 and comes into contact with a cylindrical contact member 67 provided at the tip of the first arm portion 68a.

Further, the second arm portion 68b of the vertical arm 68 is connected to the feed base 4.
0 and intersects with the horizontal arm 54 below. And the second arm portion 68b
A sector gear 7o integrally formed at the tip of the sewing machine is meshed with a pinion 74 of a vertical movement motor 72 disposed laterally on the sewing machine body. Therefore, this vertical movement motor 7
2, the vertical arm 68 rotates in the vertical direction about the pivot pin 69 as a fulcrum, as shown in FIGS. 5(a) and 5(b). The feed table 4o that comes into contact with is driven up and down. At this time, the feed table 4o and the feed 1 #36 are guided by a vertical shaft 58 provided on the first arm portion 54a of the horizontal arm 54, and move up and down while maintaining the parallel posture.

That is, when the feed fr40 is biased by the vertical movement mechanism 44 and given vertical movement, the feed fr40 moves to its top dead center position h.
+ and the bottom dead center position hb, the back and forth movement mechanism 42 drives the work cloth 35 forward and backward, respectively, thereby moving the work cloth 35 placed on the bed portion 32 in a predetermined direction. In addition, by controlling the vertical movement motor 72 by a control device 80 shown in FIG. 6, the swing angle of the vertical arm 68 can be adjusted, and the amount of protrusion of the feed fr 36 from the throat plate 34 can be adjusted. has been done.

Further, a hook 78 is rotatably supported on the board 50 at a position close to the feeder 836 (see FIG. 3), and the hook 78 is rotationally driven by a stepping motor 76 shown in FIG. It is now possible to do so.

(About the electrical control system) FIG. 6 is a block diagram showing an outline of the electrical control system that controls each operating member of the sewing machine according to the embodiment, and shows a control device 80 based on a microprocessor (CPU).
It is equipped with This control device 80 includes a pattern selection operation section 16. A start/stop switch 26, a timing signal generator 93, and a seasonal detector 39, which will be described later, are connected, respectively. The timing signal generator 93 includes a sewing machine motor 82, a needle bar swing control motor 89, and a longitudinal movement motor 64.
, and generates signals related to the operation timings of the rotary hook driving stamping motor 76 and the vertical movement motor 72.

Further, the control device 80 is connected to the feed dog 3 via a drive circuit 83.
6's longitudinal movement motor 64, the vertical movement motor 72 of the feed control 36 via the drive circuit 84, the sewing machine motor 82 via the drive circuit 81, and the needle bar swing control motor 89 and the drive circuit 94 via the drive circuit 90. Stepping motors 76 for driving the hooks are respectively connected through them.

Further, the ROM 12 as a memory element stores pattern data 91 that can be selected by the pattern selection operation unit 16, and the read/write RAM 92 temporarily stores the results of calculations by the control device 80, etc. By operating the pattern selection operation section 16, a code signal corresponding to the selected pattern is supplied to the control device 80.

The seasonal detector 39 connected to the control device 80 is connected to the presser foot 2.
9, that is, the seasonality of the work cloth 35, can be detected and the data can be input to the control device 80.

Then, the control device 80 controls the top dead center position hl(
The vertical motion motor 72 is controlled by calculating the value of the protrusion amount (protrusion amount) that is the optimum position for the inputted seasonal season, and converting this value into the swing angle of the vertical arm 68.

In addition, when setting the top dead center position hl (protrusion amount) of the feed dog 36, the bottom dead center position hb of the feed dog 36, the throat plate 34
Calculated based on the top surface position (0 point position). Furthermore, the bottom dead center position hb of the feed fr36 can be varied as necessary.

(Regarding the flow of the control system) Next, FIG. 7 shows an operation flow when each signal is supplied to the control device 80 in the sewing machine according to the embodiment. After preparations for sewing such as threading are completed, the sewing machine 10 is started (powered on) at step 101 (hereinafter referred to as "S") in FIG. 7, and a desired pattern is selected from various patterns stored in the ROM 12. A pattern is selected using the pattern selection operation section 16 (S102).

Next, in 5103, it is confirmed whether the start/stop switch 26 has been turned on, and if the answer is YES, the process advances to 5104. At step 5104, the seasonality of the work cloth 35 pinched between the presser foot 29 and the throat plate 34 is detected, and this detected value is input to the control device 80.

Then, based on the detected value input to the control device 80,
The top dead center position hl (protrusion amount) of the feed dog 36 is determined (
S 105).

Next, at 5106, each drive motor 82, 89, 64°72
to perform the required sewing. Next, it is checked in 5107 whether the start/stop switch 26 has been turned on again, and if the answer is negative (NO), it is checked in 5108 whether the pattern data 91 in the ROM 12 has been completed. If not completed (NO), the process returns to step 8106 and continues to drive each drive motor 82, 89°64, 72 to perform sewing.
If the pattern data 91 is completed (YES), each drive motor 82, 89, 64, 72
Stops driving.

Operation of the Embodiment Next, the actual use of the cloth feeding device of the sewing machine according to the present embodiment will be explained.

First, during the sewing preparation work, the bed portion 3 of the sewing machine 10 is
At the same time, the workpiece cloth 35 is placed on the presser foot 29 and the presser foot 27 is lowered by operating the presser foot lifter 37, and the workpiece cloth 35 is pressed between the presser foot 29 and the throat plate 34, as shown in FIG. At this time, as shown in FIG. 1, the movable lever 41 that contacts the presser bar holder 33 fixed to the presser bar 27 via the pin 45 rotates by a predetermined angle, and from this rotation angle, the seasonal detector 3
9 detects the seasonality of the work cloth 35. The detected value by the detector 39 is input to a control device 80 as shown in FIG.
Here, a value suitable for the season is calculated to determine the top dead center position b+ (protrusion amount) of the feed spear 36.

Also, before the sewing machine 10 starts operating, the pattern selection operation section 1
6 to input the desired pattern to be sewn. The pattern selected by this input is displayed on the display section 18, for example.

Next, when the start/stop switch 26 is operated to input a start signal to the control device 80, the sewing machine motor 82 is driven via the drive circuit 81 according to the control program stored in the ROM 12, and the needle bar 30 is moved. It is moved up and down. Further, according to the pattern data 91 stored in the ROM 12, the needle bar swing control motor 89 is driven by the drive circuit 90, and the needle bar 30 is swung in a direction perpendicular to the cloth feeding direction. Further, according to the pattern data 91 stored in the ROM 12, the forward/backward movement motor 64 of the feed 11 #36 is driven via the drive circuit 83, and the seasonal detector 39
The vertical movement motor 72 is driven via the drive circuit 84 in accordance with data determined based on the detected value.

The above-mentioned pattern data 91 is applied to the work cloth 35 placed on the bed portion 32 by the vertical movement and rocking movement of the needle bar 30 and the vertical movement and back-and-forth movement of the feed pin 36 which are controlled in advance in this manner.
Various patterns are sewn in sequence according to the following. At this time,
Amount of protrusion of the feed chamber 36 from the top surface of the throat plate (top dead center position hl)
is automatically set to the optimum value for guiding the work cloth 35 to be processed, so that smooth transfer of the work cloth 35 can be achieved.

Next, when sewing a work cloth 35 with a different cloth conductivity from the work cloth 35 treated in the previous sewing operation, a new work cloth 35 is sewn.
is placed on the bed portion 32 and the work cloth 35 is pressed between the throat plate 34 and the presser foot 29, and the seasonal detector 39 detects the new work cloth 35 as described above. Detected. Then, based on this detected value, a new top dead center position h+ (protrusion amount) of the feed dog 36 is determined, and smooth transfer of the new work cloth 35 is achieved.

In this embodiment, a case has been described in which the vertical movement mechanism and the longitudinal movement mechanism of the feed head are driven by independent dedicated motors. is applicable. Further, the hook may be driven by a conventional sewing machine motor without using a dedicated motor.

As described in detail, according to the cloth feeding device of the sewing machine according to the present invention, the workpiece cloth placed on the bed portion is compressed between the presser foot and the throat plate to guide the workpiece cloth. can be detected. It is possible to automatically set the optimum protrusion amount of the feeder for guiding the material, and by simply controlling a dedicated drive source that gives vertical movement to the feeder based on this set value,
This allows smooth transfer of the processed cloth at all times. Also,
The amount of protrusion of the feed weight is automatically adjusted by simply pressing the work cloth between the presser foot and the throat plate, so the operator does not have to perform complicated and time-consuming switching operations. can reduce the burden of Further, by automating the adjustment work of the amount of protrusion of the feed dog, there is an advantage that there is no possibility of an operator's operation error and that appropriate cloth feed can be achieved at all times.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a schematic configuration of a sewing machine in which the present invention is preferably implemented, FIG. 2 is a schematic perspective view showing a feed dog feeding mechanism in a sewing machine according to an embodiment, and FIG. Fig. 2 is a plan view of the feed mechanism shown in Fig. 2, Fig. 4 is a front view of the feed mechanism shown in Fig. 2, and Figs. Explanatory front view shown in Figure 6
FIG. 7 is a block diagram of the control system of the sewing machine according to the embodiment.
The figure is a flowchart diagram of a sewing machine according to an embodiment,
FIG. 8 is a graph diagram showing the movement trajectory of the sewing needle and the feed dog. 29... Presser foot 34... Throat plate 34a...
Slit 35...Working cloth 36...Feed #
39...Seasonal field detector 42...Back and forth movement mechanism
44... Vertical movement mechanism 72... Vertical movement motor 8
0... Control device patent applicant Brother Industries, Ltd.

Claims (1)

[Scope of Claims] A presser foot (29) disposed so as to be movable up and down above the throat plate (34) on which the work cloth (35) is placed, and the throat plate (34)
A feed dog (36) located facing a slit (34,) drilled in In a sewing machine equipped with a back-and-forth movement mechanism (42) that provides
A dedicated drive source (72) that independently drives the vertical movement mechanism (44) of the feed dog (36), and a height of the presser foot (29) that changes according to the thickness dimension of the work cloth (35). Based on the detection means (39) for detecting the position and the detected value obtained by the detection means (39), the drive source (72) of the vertical movement mechanism (44) is controlled to control the feed dog (36). 1. A cloth feeding device for a sewing machine, comprising a control means (80) for adjusting the amount by which the needle protrudes above the throat plate (34).