JPH09308785A - Looper mechanism for sewing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently fabricate an upper looper mechanism at low price and improve abrasion resistance of a sliding part. SOLUTION: An upper looper guide metal 3 is turnably attached to the left end of an upper looper guide metal 2 and a through-hole is formed therein. A base material part of the upper looper guide metal 3 is formed by an appropriate metal material of cast iron (FC 150, or the like) and soft nitriding processing is applied on the whole surface including the internal face of the through-hole so as to provide it with abrasion resistance. The central part of the looper attaching member 4 is slidably inserted in the through-hole of the upper looper guide metal 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sliding part of a looper mechanism of a sewing machine.

[0002]

2. Description of the Related Art Conventionally, the movement of an upper looper mechanism of an overedge stitch sewing machine is proportional to the number of rotations of a main shaft, so that the sliding portion of the mechanism is forced to slide at high speed, and the vertical reciprocation and rotation of Due to the combined curved movement, wear occurs in the part that causes the movement of the upper looper. Also, it is known that backlash and noise are generated due to wear. As one means for solving such problems, the surface of the sliding portion of the so-called upper looper mount 4 is subjected to ion nitriding treatment, hard chrome treatment or the like in order to improve wear resistance, and the surface hardness of the metal is The so-called upper looper guide 3 is made of an aluminum alloy that is lightweight and has a strong mechanical property by heat treatment, and the surface of the sliding part is anodized so that it becomes harder. It was used in combination with those that have been subjected to.

[0003]

However, among the combinations of the upper looper mount and the upper looper guide as described above, if an aluminum alloy material is used as the material of the upper looper guide, the mechanical properties of the aluminum alloy cause a stickiness. Grinding processing time (aluminum processing speed 0.0
03 min / mm) is iron-based metal (iron-based processing speed 0.005
Min / mm), the production efficiency is low and the processing cost is high. Further, in the alumite treatment for making the surface hard, the power consumption is high due to the equipment required for the treatment, and as a result, it becomes a component with a high unit price.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide an inexpensive looper mechanism for a sewing machine with high production efficiency.

[0005]

In order to achieve this object, a looper mechanism for a sewing machine according to claim 1 of the present invention comprises a cast iron looper whose sliding surface or rocking surface is soft-nitrided. It is provided with a looper attachment member or a support member to be attached. Therefore, it imparts wear resistance to a cast iron member that can be processed at high speed.

A looper mechanism for a sewing machine according to a second aspect of the present invention includes a cast iron support member having an inner surface of a through hole subjected to a soft nitriding treatment, and the looper mounting member is supported by a recessed portion having wear resistance. ing.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, in the machine frame 1 of the sewing machine,
The guide support member 2 is fixed, and a cylindrical upper looper guide metal 3 (support member) is rotatably attached to the left end of the guide support member 2, as shown in FIG. In the upper looper guide metal 3, a through hole penetrating in the vertical direction is formed so as to be substantially orthogonal to the axis of the cylinder of the upper looper guide metal 3. The upper looper guide metal 3 has a base material portion formed of an appropriate iron-based metal material such as cast iron (FC150, etc.), and the cast iron is excellent in its machinability due to its mechanical properties, and the grinding time (Processing speed 0.005 to 0.013 min / mm) is the processing time of aluminum alloy (processing speed 0.
Compared with 003 min / mm), the parts can be manufactured easily at low cost. The entire surface including the inner surface of the through hole of the upper looper guide metal 3 is subjected to soft nitriding treatment so as to have wear resistance.

In the soft nitriding treatment, the parts are heated to a high temperature (570 ° C.) in a solvent containing active nitrogen and heated and held in a salt bath gas atmosphere (gas soft nitriding) for 0.5 to 4 hours. The parts were made of 5-15 μm iron-nitrogen-carbon compound layer, 0.1-0.4 mm diffusion layer and HV500-6.
A surface hardness of about 00 can be obtained. Abrasion resistance is obtained by the compound layer having a thickness of 5 to 15 μm, and the wear resistance is 0.1 to 0.
A 4 mm diffusion layer provides wear and erosion resistance.

In the through hole of the upper looper guide metal 3,
A central portion of the rod-shaped looper attachment member 4 is slidably inserted, and an internal thread for a cut or a set screw is formed at the upper end of the looper attachment member 4 so that the upper looper can be fixed. The looper attachment member 4 moves together with the upper looper.

The lower end of the looper mounting member 4 is connected to a known power transmission mechanism, and the upper end of the looper mounting member 4 is curved around the upper looper guide metal 3 by a swing shaft that swings by the rotation of the main shaft. Draw a locus of circles and move. At this time, the upper looper is configured to reciprocate along a circular arc path. When the upper looper moves, a load is generated on the looper attaching member 4 and the upper looper guide metal 3. Further, the upper looper guide metal 3 itself also rotates with the swing of the upper looper.

By subjecting at least the surface of the sliding surface of the upper looper guide metal 3 to the soft nitriding treatment, it is possible to improve wear resistance and provide a low-priced component by easy processing. Furthermore, by reducing the wear, noise due to backlash is also reduced. We also provide parts that maintain durability. Also,
In the above-described embodiment, the sliding surface on the inner surface of the through hole is soft-nitrided.
May be made of cast iron and the sliding surface thereof may be soft-nitrided. In the above-described embodiment, the sliding surface is soft-nitrided.However, in a mechanism such as a looper mechanism of a sewing machine that causes wear of parts, soft-nitriding is applied to the rocking surface and the rotating surface. May be. Further, similarly to a member (such as a transmission mechanism from the main shaft) that receives a load for causing the swing of the looper, the contacting sliding surface or swing surface may be soft-nitrided. The term "sliding surface" or "swinging surface" as used in the present invention refers to a portion where members contact each other.

[0013]

As is apparent from the above description, according to the looper mechanism of the sewing machine according to claim 1 of the present invention, cast iron having better workability than that of the conventional one is soft-nitrided to form a looper. It is possible to efficiently and inexpensively create a component that produces movement. In addition, it is possible to manufacture a part that creates the movement of the looper while maintaining durability.

According to the looper mechanism of the sewing machine of the second aspect of the present invention, since the soft nitriding treatment is used, it is possible to easily perform the curing treatment on the recessed portion of the inner surface of the through hole.

[Brief description of drawings]

FIG. 1 is a front view of components of an upper looper mechanism.

FIG. 2 is a perspective view of a cross section of components of the upper looper mechanism.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Machine frame 2 Guide support member 3 Upper looper guide metal (support member of this invention) 4 Looper attachment member

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tomoharu Mizutani 15-1 Naeshiro-cho, Mizuho-ku, Nagoya-shi Brother Industries Ltd.

Claims (2)

[Claims] 1. A looper mechanism of a sewing machine comprising a looper attachment member for attaching a looper and a support member for slidably or swingably supporting the looper attachment member, wherein at least one of the looper attachment member and the support member is cast iron. A looper mechanism for a sewing machine, characterized in that the sliding surface or swinging surface of a member made of cast iron is soft nitrided. 2. The support member is made of cast iron, the looper attachment member is supported by a through hole, and the inner surface of the through hole is soft-nitrided. The looper mechanism of the described sewing machine.