JPH0444883U

JPH0444883U -

Info

Publication number: JPH0444883U
Application number: JP8512790U
Authority: JP
Priority date: 1990-08-11
Filing date: 1990-08-11
Publication date: 1992-04-16
Anticipated expiration: 2005-08-11
Also published as: JPH0740388Y2

Description

[Brief explanation of drawings]

第１図〜第７図は本考案の実施例に係り、第１
図は糸締まり補正機構を含むミシン主要部の斜視
図、第２図は糸締まり補正機構の主要部の斜視図
、第３ａ図は正送り時の送り機構と下糸繰出し制
御体との関係を示す図、第３ｂ図は正送り時の送
り歯の運動を示す略図、第４ａ図は逆送り時の送
り機構と下糸繰出し制御体との関係を示す図、第
４ｂ図は逆送り時の送り歯の運動を示す略図、第
５図は正送り時における下糸経路により下糸繰出
し量を説明する図、第６図は逆送り時における下
糸経路により下糸繰出し量を説明する図、第７図
は本考案の糸締まり補正機構による送り反転時の
縫目例を示す図である。第８図〜第１１図は従来
例に係り、第８図は従来例における送り反転時の
縫目例を示す図、第９図〜第１１図は第８図に示
すような縫目が形成される過程を示す図で、第９
図は送り反転時に下糸にたるみが発生した状態、
第１０図は第９図の状態から布送りに入つた状態
、第１１図は第１０図の状態から更に進み天秤の
糸締めにより上吊り現象が発生した状態を示す図
である。ＬＴは下糸、２は送り歯、２ａは送り歯のブリ
ツジ部、１６は送り調節器、３４は下糸繰出し制
御体、３４ａは下糸繰出し制御体の制御板、４４
は制御体解除手段、５０は糸締まり補正機構であ
る。 Figures 1 to 7 relate to embodiments of the present invention;
The figure is a perspective view of the main parts of the sewing machine including the thread tightness correction mechanism, Fig. 2 is a perspective view of the main parts of the thread tightness correction mechanism, and Fig. 3a shows the relationship between the feed mechanism and the bobbin thread payout control body during normal feed. Fig. 3b is a schematic diagram showing the movement of the feed dog during normal feeding, Fig. 4a is a diagram showing the relationship between the feeding mechanism and the bobbin thread pay-out control body during reverse feeding, and Fig. 4b is a schematic diagram showing the movement of the feed dog during reverse feeding. A schematic diagram showing the movement of the feed dog; FIG. 5 is a diagram illustrating the amount of bobbin thread paid out according to the bobbin thread path during forward feeding; FIG. 6 is a diagram explaining the amount of bobbin thread paid out according to the bobbin thread path during reverse feeding; FIG. 7 is a diagram showing an example of stitching when the feed is reversed by the thread tightness correction mechanism of the present invention. Figures 8 to 11 relate to the conventional example, Figure 8 is a diagram showing an example of stitches when the feed is reversed in the conventional example, and Figures 9 to 11 are stitches formed as shown in Figure 8. This is a diagram showing the process of
The figure shows a situation where slack has occurred in the bobbin thread when the feed is reversed.
FIG. 10 shows a state in which cloth feeding has started from the state shown in FIG. 9, and FIG. 11 shows a state in which the thread take-up is tightened further from the state shown in FIG. LT is a bobbin thread, 2 is a feed dog, 2a is a bridge portion of the feed dog, 16 is a feed adjuster, 34 is a bobbin thread pay-out control body, 34a is a control plate for the bobbin thread pay-out control body, 44
Reference numeral 50 indicates a control body release means, and 50 indicates a thread tightness correction mechanism.

Claims

[Claims for Utility Model Registration] The bottom of the sewing machine is formed with a control plate whose vertical position is controlled in relation to the inclination of the feed adjuster of the sewing machine and which controls the amount of bobbin thread fed out in cooperation with the bridge portion of the feed dog. A thread tightness correction mechanism for a sewing machine, comprising a thread feeding control body and configured such that the amount of bobbin thread fed out during reverse feeding is smaller than during forward feeding. In the case of a stitch pattern in which reverse feed is continuous, the sewing machine is characterized by comprising a control body release means for releasing the control plate to a position in which it does not act on the bobbin thread during reverse feed except when the first reverse feed is reversed. A thread tightness correction mechanism for a sewing machine according to the claims.