JPS6021753B2 - Sewing machine presser foot confirmation device - Google Patents

Description

[Detailed Description of the Invention] This invention is a sewing machine that can select and form various different sewing patterns such as zigzag, buttonhole, embroidery, etc., and has different types of presser feet prepared for each of the various sewing patterns. The present invention relates to a presser foot confirmation device for a sewing machine for checking whether an appropriate type of presser foot corresponding to a selected sewing pattern is attached to a presser foot bar.

Conventionally, in sewing machines that can perform the various sewing patterns mentioned above, such as home sewing machines, various presser feet are prepared according to each sewing pattern, and when a pattern is selected, the corresponding presser foot is supported at the bottom end of the presser foot. However, if the operator forgets to replace the presser foot, or attaches a different type of presser foot by mistake, the needle dropout hole of the presser foot may be too small for the needle oscillation. The needle drop point may not match the needle drop hole of the presser foot, causing the needle to engage the presser foot, causing accidents such as breaking the needle or damaging the presser foot, or the presser foot may not align with the needle drop hole of the presser foot. When the needle drop hole is too large, the fabric presser at the needle drop point becomes insufficient, causing the fabric to flap and skip stitches, resulting in a defect that deteriorates the quality of the sewn product.

The present invention focuses on the fact that the height from the bottom surface of the presser foot to the locking position with respect to the presser foot differs depending on the type of presser foot, and aims to eliminate the drawbacks of the above-mentioned conventional presser foot.

An embodiment of the present invention will be described with reference to the drawings. The sewing machine 1 is equipped with an electric memory such as a ROM that stores sewing data related to needle swing and cloth feeding for forming various pattern stitches such as zigzag patterns, embroidery, and buttonholes. Storage means M (fifth
), a needle swinging means (not shown) such as a stepping motor that swings the needle (not shown) in the cloth feeding direction, which is controlled by the sewing data in the storage means M, and the feed momentum of the feed dog. It has a feed control means (not shown) such as a stepping motor that follows the sewing data in the storage means M, and also has a large number of presser feet 3 of different types corresponding to each pattern sewing. The presser foot 2, which is supported movably up and down on the frame of the sewing machine 1, has one of the presser feet 3 removably supported at its lower end by a locking piece 4 such as a screw, and as described above, the presser foot 2 has a presser foot 3 attached to the bottom end of the presser foot 2. Actuation means (not shown)
A downward elastic force is applied by a coiled spring (not shown) whose spring pressure is controlled by a coil spring (not shown).

A substantially L-shaped support 5 is fixed to the upper end of the presser birch 2, and the upper end of the detection twill 7 of the cloth thickness detection means 6 is fixed to the horizontal portion 5a of the support 5. The cloth thickness detecting means 6 fixed to the machine frame is an inductance type stroke sensor, and the lower end of the detecting member 7 is moved movably in the axial direction in the shaft hole 9a of the bobbin 9 around which the coil 8 is wound. The inductance of the coil 8 changes in accordance with the iron insertion position with respect to the shaft hole 9a of the shaft 7.
The oscillator LI is constructed by a capacitor connected to the oscillator LI.
As shown in FIG. 4, the internal circuit of the detection means 6 includes a second oscillator L2 having the same characteristics as the oscillator LI, and the outputs of the first and second oscillators L1 and L2 are connected to a mixer K and a filter. The frequency divider N divides the output of the filter F, and the transistor Tr whose opening/closing is controlled by the frequency divider N. Therefore, the frequency output from the transistor Tr is the lowest frequency of the detection rod 7. The data corresponds to the distance from the point, and the output from the transistor Tr is digitally converted in an F/D converter (not shown) to generate a digital code detection signal. During this conversion, the data m from the transistor Tr is converted into data corresponding to the distance from the throat plate to the locking point of the presser foot 3 (with respect to the presser foot twill 2) with reference to the state in which the presser foot 3 is in contact with the throat plate. , therefore the output signal of the detection means 6 has distance data. A panel 10 fixed to the front surface of the sewing machine 1 has a display section 11 with patterns corresponding to various sewing patterns stored in the memory means, and a display section 11 that displays patterns corresponding to the various sewing patterns stored in the memory means. The panel 1 is provided with an operating body 12 for specifying and displaying a corresponding display section 11, and the two constitute a pattern selection means.The panel 1 is also provided with a light emitting body 13 (LED).

The dial 14 generates a signal for changing the cloth feed amount by the feed control means or setting the feed amount for sewing patterns such as straight stitches and zigzag stitches. Although not shown, a rotational position detection means PS (FIG. 5) is provided which is arranged in relation to the main shaft of the sewing machine and detects the timing at which the feed dog of the cloth feed means sinks below the throat plate. Next, the electric circuit shown in FIG. 5 will be explained.

SD is a selection circuit that is associated with the pattern selection means and generates selection signals of different digital codes corresponding to the selected sewing patterns. SF is a setting circuit that generates a cloth feed signal of a digital code corresponding to the cloth feed amount in relation to the rotational position of the dial 14. NR is a storage circuit,
In accordance with the selection signal from the selection circuit SD, data p of each stitch pitch of the corresponding pattern is input from either the setting stitch SF or the storage means M according to the selected pattern and stored. The M circle is a memory circuit that stores data regarding the distance x regarding the presser foot to be used for each sewing pattern, and the data of the corresponding presser foot is read out in response to a selection signal from the selection circuit SD. RC is a latch circuit which reads and holds the detection signal from the cloth thickness detection means 6 when inputting the detection signal of the feed dog sinking timing from the rotational position detection means PS. CO is a correction circuit which inputs the detection signal from the cloth thickness detection means 6 and presser foot distance data x from the memory circuit MF and outputs a calculated value of d (cloth thickness)=1-x. AC is an arithmetic circuit which receives pitch data p from the storage circuit NR and cloth thickness data d from the correction circuit CO and outputs a calculated value of p+d. TD is an operating circuit that acts on an actuating means (not shown) such as a magnet that regulates the yarn let-out of a well-known yarn letting-out means, and controls the actuating means to let out an amount of yarn corresponding to the output data from the arithmetic circuit AC. do. As mentioned above, FD is an operating circuit that acts on the operating means that acts on the coiled spring of presser bar 1, and correction circuit CO
The pressing force by the presser foot 2 is controlled to be set to a predetermined value based on the cloth thickness data d from .

CP is a comparison circuit which compares the data x from the memory circuit MF and the output data from the fabric thickness detection means 6 and generates an H level output when the two do not match. The LED (light emitter 13) connected to P in the comparison circuit lights up when the H level is input, and the buzzer operating circuit connected to the LED lights up when the H level is input.
An alarm is generated for a certain period of time depending on the level input. It is assumed that the comparator circuit CP holds its output until an operation signal related to the presser foot lifting operation or a new selection signal from the selection circuit SD is generated and reset.

The present invention has the above-mentioned configuration, and its operation will be explained next.

Before sewing work, a presser foot 3 corresponding to the pattern to be sewn is selected and supported on the lower end of the presser bar 2.

At this time, when the distance from the upper surface of the throat plate of the locking point of the presser foot 3 to the presser foot 2 changes, the detection rod 7 fixed to the upward movement of the presser foot 2 moves in the vertical direction, that is, the marking line of the gutter hole 9a of the bobbin 9. The inductance of the coil 8 changes as the coil 8 moves in this direction. As a result, frequency data m corresponding to the distance is generated from the transistor Tr, and an output signal of a digital code corresponding to the distance saw is generated from the cloth thickness detecting means 6, which has been digitally converted by the F/D converter. At this time, the pattern selection means 11,
12, the sewing data and presser foot data regarding the selected pattern are generated from the selection circuit SD, and when the data Z of the detection signal from the cloth thickness detection means 6 matches the presser foot data x, that is, the height of the presser foot is determined. When x matches the detected value, it is confirmed that the presser foot 3 is the specified one, but when it does not match, it means that a different type of presser foot 3 than the one corresponding to the selected pattern has been attached. , the light emitter 13 lights up and the buzzer BZ generates an alarm. Furthermore, if the feed dog has not sunk below the throat plate, or if the fabric is placed between the throat plate and the presser foot, alignment cannot be achieved even if the appropriate presser foot 3 is attached. The light will turn on and the buzzer will sound an alarm. When the cloth W is placed below the presser foot 3, the presser foot 3 rises and the detection bar 7 of the cloth thickness detection means 6 detects the bobbin 9.
The isoductance of the coil 8 changes, the frequency of the transistor Tr changes, and the output data from the detection means 6 via the F/D converter changes the thickness d of the cloth W. The included distance is (dx).

When the sewing machine 1 is driven from this state, the data is read into the latch circuit RC when the feed dog sinks, and the correction circuit CO
is output to. The correction circuit CO inputs the presser foot data x and the detection data from the memory circuit MF, calculates Z-x, inputs the calculated value to the calculation circuit AC and the operation circuit FD, and operates. The circuit FD controls the presser foot actuating means according to the thickness d of the cloth W based on the calculated value, and sets the pressure of the coiled spring of the presser rod 2 so that a predetermined presser pressure is achieved.
Further, the arithmetic circuit AC inputs the stitch pitch data p from the storage circuit NR, calculates p+d using the cloth thickness data d from the correction circuit CO, and sends the calculated value to the action circuit TD.
Based on the calculated value, the operating circuit TD operates the actuating means to control the amount of needle thread being fed out by the thread feeding means. In this embodiment, the detection data of the cloth thickness detecting means 6 is used as the output data to detect the moving distance using the lowest point of the detection twill 7 as a reference, and the calculation of 1× is performed in the correction circuit CO. However, instead of that, a presser foot that uses the position of the detection base 7 corresponding to the height of one type of presser foot, for example, a straight line presser foot, as a reference value and uses the data of the detected value. It is also possible to convert the reference value soo according to the type of foot and then correct the value son-x (x is the height of the presser foot for straight lines).

In this embodiment, the sewing data is stored in an electrical storage means such as a ROM, but the sewing data may be stored in a mechanical storage means such as a cam.

Further, in this embodiment, an inductance type stroke sensor is shown as the detection means 6, but other potentiometers using magnetism, light, resistance, etc. may be used.

As described above, according to the present invention, a plurality of presser feet 3, each of which can be attached and detached from the lower end of the presser foot, each having a different distance from the bottom surface to the lower end of the presser foot according to the sewing pattern, are arranged in relation to the presser foot. Detection device that detects the vertical position of the presser foot when the bottom surface of the presser foot attached to the presser foot comes into contact with the throat plate, and generates a detection signal corresponding to the distance from the lower end of the presser foot to the throat plate in relation to the detected position. means 6, a detection signal and distance data for separately storing distance data regarding the distance from the bottom surface of each presser foot to the lower end of the presser foot, and reading distance data of the presser foot corresponding to the sewing pattern selected by the sewing control means; The comparison circuit CP compares the two distances and generates an action signal when the two distances do not match. By attaching the foot and pressing it against the throat plate, you can check whether the attached presser foot is the type for forming the selected sewing pattern, so even if you accidentally attach a different type of presser foot, you can continue working. Because the person will be informed,
In addition to extending the life of the device without damaging the presser foot or needle, the presser foot with a needle drop hole suitable for sewing can always press the fabric, which prevents skipped stitches and improves the quality of sewn products. An improvement effect can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of the sewing machine of this embodiment, Fig. 2 is an explanatory diagram for explaining each data, Fig. 3 is a basic explanatory diagram of an inductance type stroke sensor, and Fig. 4 is an internal circuit of the stroke sensor. 6 are block diagrams showing the electric circuit of this embodiment. Figure 1 Figure 2 Figure 3 Figure 4 Figure Ship

Claims (1)

[Claims] 1. A sewing control means that separately stores stitch information regarding a plurality of different sewing patterns, selects stitch information by operation, and connects it to the stitch forming mechanism; a presser foot 2 that receives an elastic force from the presser foot, a plurality of presser feet 3 that can be individually attached to and detached from the lower end of the presser foot and have different distances from the bottom to the lower end of the presser foot depending on the sewing pattern; Detects the vertical position of the presser foot when the bottom surface of the presser foot placed on the presser foot contacts the throat plate, and generates a detection signal corresponding to the distance from the bottom end of the presser foot to the throat plate in relation to the detected position. a detection means 6; a storage means MF which separately stores distance data regarding the distance from the bottom surface of each presser foot to the lower end of the presser bar, and reads distance data of the presser foot corresponding to the sewing pattern selected by the sewing control means;
Comparison circuit CP that compares the detection signal and distance data and generates an action signal when the two distances do not match, and alarm means BZ, 1 that operates in relation to the action signal and is capable of giving an alarm.
3. A presser foot confirmation device for a sewing machine, which is equipped with: