JPH01131694A - Detector for residual amount of bottom thread in sewing machine - Google Patents

Abstract

PURPOSE: To detect the residual amount of a bobbin thread without using a detecting means using light or magnetism, and to facilitate winding of the bobbin thread by detecting the residual amount of the bobbin thread of a sewing machine by opening/ closing of an electric circuit formed of a bobbin, a bobbin case, a shuttle, a sewing machine main body and a bobbin detecting member. CONSTITUTION: When the bobbin thread 18 is sufficiently wound on the bobbin 7, an electrically conductive member 19 disposed over the axial cylinder part 8 of the bobbin 7 is depressed by the winding pressure of the bobbin thread 18 and the member 19 is cut off from a conductive receiving piece 12 connected to a conductive surface 11. In a state when the bobbin thread 18 remains on the side of the flange 10 of a partitioning flange 13 but the bobbin thread 18 does not exist on the other side, the winding pressure applied to the member 19 is completely released and the member 19 is returned upward. Then, this and the piece 12 connected to the surface 11 are electrically connected with each other. At the time of operating a thread cutting lever in this state, the braking member 26 of the bobbin is engaged with the surface 11 of the bobbin 7. Thus, the electric circuit becomes a closed circuit to energize an operation part 28 for display by a lamp, a buzzer, etc., or to stop the sewing machine.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a lower thread remaining amount detection device for a sewing machine that detects the remaining amount of lower thread wound around a bobbin of a sewing machine when the thread is trimmed or when the sewing machine is stopped.

[Prior Art] In conventional devices of this kind that use detection means that utilize light or magnetism, there is a possibility that the bobbin thread that has been wound around the bobbin is consumed. When the movably mounted detected object moves in the axial direction and the detected object approaches the detector installed outside the hook, the detector alerts the operator that there is little bobbin thread left. There is a known system in which the sensor is activated by detecting the slightest movement of the object to be detected, but this requires a sufficient distance between the object and the object to be detected. However, it has the disadvantage that the upper thread is likely to get caught on the object to be detected. And in order to eliminate this shortcoming,
Jikosho has developed a sensor that detects the amount of bobbin thread remaining on the bobbin, which is installed on the lever that prevents the bobbin from idling when the bobbin thread is trimmed, so that it does not interfere with the needle thread passing through the hook during sewing. This is proposed in Japanese Patent No. 59-41813.

[Problems to be Solved by the Invention] In the above-mentioned conventional technology, since the amount of bobbin thread 1A is detected using a detection means that uses light or magnetism, malfunction may occur due to dirt such as lint or oil. In addition, when winding the thread around the bobbin, it is necessary to slide the bobbin thread detection rod against the spring, so there is a problem that the bobbin thread winding work is ri (J). Was.

SUMMARY OF THE INVENTION Accordingly, the present invention provides a bobbin thread remaining amount detecting device for a sewing machine that can detect the remaining bobbin thread amount without using detection means using light or magnetism, and can easily wind the bobbin thread. With the goal.

[Means for Solving the Problems] In order to achieve the above object, the bobbin thread remaining amount detecting device for a sewing machine of the present invention has a bobbin detecting member in an insulated state that can contact the bobbin flange. Rotatably supported on the main body,
A conductive surface is formed on the flange surface that the detection member can contact, and the conductive surface and the winding pressure of the bobbin thread cause the conductive surface to be electrically connected to the conductive surface in accordance with the release state of the winding pressure. In this way, a conductive member is provided at intervals on the outer peripheral surface of the shaft cylinder portion of the bobbin, and a conductive contact piece electrically connected to the conductive member is electrically connected to the bobbin case when the bobbin is set. The sensing member is provided on the bobbin, and a power source is electrically connected to the sensing member and the sewing machine main body.

[Function] With the above configuration, the bobbin thread remaining amount detecting device of the present invention can be used for detecting the amount of bobbin thread remaining in the sewing machine. Even if the detection member of the bobbin comes into contact with the conductive surface of the bobbin during cutting or when the sewing machine is stopped, the electrical circuit consisting of the conductive member, conductive contact piece, bobbin case, hook, sewing machine body, detection member, conductive surface, and power source remains disconnected. It is in.

On the other hand, when the remaining amount of the bobbin thread decreases, the winding pressure of the bobbin thread is released and the conductive member is electrically connected to the conductive surface. When the sewing machine is stopped and the sensing member comes into contact with the conductive surface of the bobbin, the electrical circuit becomes a closed circuit and a detection signal is output.

[Embodiment 1] Hereinafter, one embodiment of the present invention will be described with reference to the accompanying drawings.

1 to 5, 1 is an outer hook that rotates in conjunction with a lower shaft 2, and inside this outer hook 1 is an inner hook 4 having a shaft 3.
is loosely fitted.

5 is a bobbin case, a hollow bobbin shaft 6 provided at the center of the bobbin case 5 is loosely fitted to the shaft 3;
The bobbin case 5 is housed in the inner hook 4 around the shaft 3. Reference numeral 7 designates a bobbin having flanges 9 and 10 at both ends of the shaft cylindrical portion 8, and the il [I cylindrical portion 8 of this bobbin 7
6 is loosely fitted. The surface of the bobbin 7 is coated with an insulating material or made of an insulating material, and a conductive plate is fixed to the outer surface of the flange 9 located on the inner bottom side of the bobbin case 5 when set. A conductive material is coated to form a conductive surface 11 . Further, a conductive receiving piece 12 is connected to the inner end of the conductive surface 11. Furthermore, a partition 13 is formed on the bobbin 7 at the center outer circumferential surface of the shaft cylindrical portion 8 and is formed upright around the entire circumference, and a hole 14 is formed in the collar 9 corresponding to the conductive receiving piece 12. A conductive receiving piece 12 is inserted into the hole 14. Further, a recessed fitting part 15 is provided in the center of the collar 9 of the bobbin 7 in the hole 1.
It is formed in communication with 4. In addition, there is a hole 1 in the partition flange 13.
A notch 16 is formed corresponding to 4. Reference numeral 17 denotes a conductive ring-shaped spring member that is fitted into the recessed fitting portion 15, and one end of this spring member 17 is bent and inserted into the hole 14 to connect to the partition blade. By loosely inserting it into the notch groove 16 of 13, it is pushed down against the spring bias by the winding pressure of the bobbin thread 18, and is separated from the conductive receiving piece 12, and the winding pressure of the bobbin thread 18 is released. Accordingly, the conductive member 19 is configured to be movable in the radial direction of the collar 9 so as to return upward and come into contact with the conductive receiving piece 12 . Also,
A portion of the spring member 17 is bent outward to form a conductive contact piece 20 that presses against the inner bottom surface of the bobbin case 5 when the bobbin 7 is pressed into position.

Reference numeral 21 denotes a rocking body rotatably supported in an insulated state by means such as intervening an insulating material (not shown) by means of stepped screws 23 on the sewing machine main body 22; A driven lever 25 is connected. A bobbin braking member 26 is a conductive detection member fixed to the other end of the oscillator 21, and works in conjunction with a known thread cutting mechanism (not shown) to engage the conductive surface 11 of the bobbin 7 during thread cutting. Together, they are designed to prevent such delusions. Also,
The 11 moving members 26 of the bobbin and the sewing machine main body 22 are electrically connected to each other via a power source 27 such as a battery or commercial power source, and an operating section 28 such as an indicator such as a lamp or buzzer, a sewing machine stop device, or a comparator that detects a signal. It is connected to the.

Next, the operation of the real power example configured as described above will be explained.

First, when the bobbin thread 18 is sufficiently wound around the bobbin 7 as shown in FIG. is pushed down, and the conductive member 19 is separated from the conductive receiving piece 12 connected to the conductive surface 11. In this state, when the thread trimming lever (not shown) is operated, the braking member 2 of the bobbin
6 rotates about the support part as a fulcrum, and the conductive surface 11 of the hobbin 7
to prevent the bobbin 7 from moving inadvertently. In this case, the conductive member 19 of the spring member 17, the conductive contact piece 20, the bobbin case 5, the inner hook 4, the outer hook 1, the sewing machine body 22, and the power source 27
and the actuating part 28, the braking member 26 of the bobbin, and the conductive surface 1 of the collar 9.
1, but since the conductive member 19 and the conductive receiving piece 12 are separated, the electric circuit is in a disconnected state, and therefore the actuating portion 28 does not operate. On the other hand, Fig. 5 (
As shown in B), when there is a remaining amount of bobbin thread 18 on the collar 10 side of the partition blade 13 but there is no bobbin thread 18 on the other side, the winding pressure applied to the conductive member 19 is completely applied. When released, the conductive member 19 returns upward, and the conductive member 19 and the conductive surface 1
1 is electrically connected to the conductive receiving piece 12 .

When the thread trimming lever is operated in this state, the braking member 26 of the bobbin engages with the conductive surface 11 of the bobbin 7 in conjunction with this operation. As a result, the electric circuit becomes a closed circuit, and the operating section 28
When the sewing machine is turned on, an indication is given by a lamp or buzzer, or the sewing machine stops.

In this way, in the above embodiment, the bobbin 7, the bobbin case 5, the inner hook 4, and the outer hook 4, which are parts normally included in a sewing machine equipped with a thread trimming mechanism, are used without using a detection means using light or magnetism. An electric circuit is constructed using the braking member 26 of the hook 1 and the bobbin, and the remaining amount of the bobbin thread 18 can be detected by the open/closed state of this electric circuit, making it easy to cross the line and prevent dirt such as lint and oil. Stable operation is possible with little influence from In addition, since the conductive member 19 is provided so as to be movable in the radial direction above the shaft cylinder portion 8 of the bobbin 7, the trouble of sliding the bobbin thread detection rod against the spring as in the conventional method is eliminated and the operation is simplified. It's easy.

Note that the present invention is not limited to the above-mentioned embodiments, and various modifications can be made within the scope of the gist of the present invention.9 For example, the means for interlocking the braking member of the bobbin, which is the detection member, with the thread cutting mechanism may be selected as appropriate. In addition, in a sewing machine that is not equipped with a thread trimming mechanism, it is possible to have an operating means such as a solenoid that independently operates the detection member, and to bring the detection member into contact with the bobbin via the operating means each time the sewing machine stops. good.

Further, the conductive member 19 and the conductive contact piece 20 may be formed as separate bodies as shown in FIG. 5, and electrically connected to each other when assembled to the bobbin 7. In addition, although we have explained the case where the conductive member and the conductive contact piece are connected in a state where the winding pressure of the bobbin thread is completely released, it is possible to wind the bobbin thread by appropriately setting the spring strength of the conductive member. The conductive member and the conductive receiving piece may be brought into contact with each other in a state where the rotation pressure is partially released.

[Effects of the Invention] The present invention detects the amount of bobbin thread remaining in a sewing machine by opening and closing an electric circuit consisting of a bobbin, a bobbin case, a hook, a sewing machine body, and a bobbin detection member. It is possible to provide a lower thread remaining amount detection device for a sewing machine that can detect the remaining amount of lower thread without using any means and can easily wind the lower thread.

[Brief explanation of the drawing]

1 to 5 show an embodiment of the present invention, in which FIG. 1 is a longitudinal sectional view, FIG. 2 is a front view, and FIG. 3 is a perspective view of a bobbin.
4 is a sectional view of the same, FIG. 5 is a sectional view showing the operating state, FIGS. Figure 7 is a cross-sectional view. 7...Bobbin 8...Shaft cylinder portion 9, 10...
Tsuba 11... Conductive surface 18... Lower thread 19...
Conductive member 20...Conductive contact piece 22...Sewing machine body 26...Bobbin detection member 27...When power is supplied Applicant Towa Seisakusho Co., Ltd. Agent Patent attorney Mamoru Ushiki't5

Claims (1)

[Scope of Claim] A bobbin thread remaining amount detection device for a sewing machine that detects the remaining amount of bobbin thread wound around a bobbin when the thread is trimmed or when the sewing machine is stopped, is rotatably supported in an insulated state on the sewing machine body. A sensing member of the bobbin that can contact the collar of the bobbin, a conductive surface formed on the collar surface that can be contacted by the sensing member, and a winding pressure between the conductive surface and the bobbin thread that separates the bobbin thread. a conductive member provided at a distance from the outer circumferential surface of the axial cylinder portion of the bobbin so as to be electrically connected to the conductive surface according to the release state of the bobbin; 1. A bobbin thread remaining amount detection device for a sewing machine, comprising: a conductive contact piece that is electrically connected to a bobbin case when set; and a power source that is electrically connected to the detection member and the sewing machine main body.