JPH0852295A - Balance device in lockstitch sewing machine - Google Patents

Abstract

(57) [Abstract] [Purpose] A balance device that is capable of performing sewing work using thin threads and sewing work using thick threads, which were conventionally performed using separate sewing machines, with one sewing machine. To provide. [Structure] In a lockstitch sewing machine in which a base end of a balance and one end of a needle bar crank are pivotally attached to a crank fixed to the tip of an upper shaft, and a crank rod pivotally attached to the other end of the needle bar crank is connected to the needle bar. An extension piece is continuously provided at the tip of the balance, and a plurality of rows of thread insertion holes for thin threads and thread insertion holes for thick threads are provided in the extension piece at predetermined intervals.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a balance device for a lockstitch sewing machine mainly used for sewing thick materials.

[0002]

2. Description of the Related Art Conventional sewing machines of this type are usually
Sewing is carried out using the No. 50) thread, and another large sewing machine is used for sewing with the thick threads such as No. 0 to No. 4. When the worker is a woman, the operation of the large-sized sewing machine is difficult and physically impossible, and a plurality of sewing machines must be installed on the sewing machine, which causes a large economical burden.

[0003]

The problem to be solved by the present invention is to solve the above-mentioned problems of the prior art, and to perform sewing from a thin thread to a thick thread by a single sewing machine. To provide.

[0004]

The means of the present invention are as follows. In a lockstitch sewing machine in which the base end of the balance and one end of the needle bar crank are pivotally attached to the crank fixed to the tip of the upper shaft, and the crank rod pivotally attached to the other end of the needle bar crank is connected to the needle bar. A balance device in which an extension piece is continuously provided at the tip of the, and a plurality of thread insertion holes for thin threads and thread insertion holes for thick threads are arranged in a plurality of rows at predetermined intervals in the extension piece.

[0005]

1 to 6 show vertical movements of a balance and a needle bar in a lockstitch sewing machine. Reference numeral 1 is an upper shaft, and 2 is a crank fixed to a tip of the upper shaft 1. Show. The base end of the balance 3 and one end of the needle bar crank 4 are pivotally attached to the crank 2, and the crank rod 5 pivotally attached to the other end of the needle bar crank 4 is connected to the needle bar 6 to rotate the upper shaft 1. With this, the balance 3 and the needle bar 6 respectively move up and down. In the present invention, the balance 3
An extension piece 3a is continuously provided at the tip of the, and a thread insertion hole 7 for a thin thread and a thread insertion hole 8 for a thick thread are arranged in a row at a predetermined interval on the extension piece 3a. The balance between the balance 3 and the needle bar 6 is such that in the case of a lockstitch sewing machine, the top dead centers of the sewing machines are always the same. FIG. 7 shows a movement curve (motion diagram) of the sewing machine. The balance 3 of FIG. 1 is sequentially moved from the raised position to the positions shown in FIGS. 2 to 6, and this movement is continuously performed. ing. FIG. 8 is a graph (motion diagram) showing the relationship between the movement of the balance and the movement of the hook. When the hook pulls in the thread, the balance loosens the thread accordingly and the thread turns around the hook. Once done, the balance will pull up the loosened extra thread. Therefore, by changing the thread insertion hole of the balance to the thread insertion hole for the thick thread, as shown by the dotted line in FIG. At the pull-in point), the thread can be loosened and the tension of the thread at the point c of the hook will not be overwhelmed. Also, when the balance is raised, the tension for pulling the thread will be large and sewing with thick thread can be done without difficulty. Become.

[0006]

According to the present invention, the thread insertion hole for the thin thread and the thread insertion hole for the thick thread are provided in a row at the tip of the balance.
Conventionally, the sewing work using the thin thread and the sewing work using the thick thread, which have been sewn by different sewing machines, can be performed by one sewing machine. Therefore, work efficiency is significantly improved,
Moreover, the economic effect is great.

[Brief description of drawings]

1 to

FIG. 6 is a side view showing vertical movement states of the balance and the needle bar of the balance device.

FIG. 7 is a motion curve graph showing the relationship between the balance and the needle bar.

FIG. 8 is a graph depicting the relationship between balance movement and sickle movement.

[Explanation of symbols]

 1 Upper shaft 2 Crank 3 Balance 3a Extension piece 4 Needle bar crank 5 Needle bar crank lock 6 Needle bar 7 Thread insertion hole for fine thread 8 Thread insertion hole for thick thread

Claims (1)

[Claims] 1. A lock stitch with a crank fixed to the tip of an upper shaft, a base end of a balance and one end of a needle bar crank being pivotally attached, and a crank rod pivotally attached to the other end of the needle bar crank being connected to the needle bar. In the sewing machine, an extension piece is continuously provided at the tip of the balance, and a thread insertion hole for a thin thread and a thread insertion hole for a thick thread are provided in a plurality of rows on the extension piece at predetermined intervals. Balance device.