Feed dog lifting height adjustable mechanism and sewing machine

Abstract

The invention provides a feed dog lifting height adjustable mechanism which comprises a main shaft, a feed lifting shaft, a dog frame, a feed dog, a first feed lifting transmission assembly connected between the main shaft and the feed lifting shaft, and a second feed lifting transmission assembly connected between the feed lifting shaft and the dog frame, wherein the first feed lifting transmission assembly comprises a feed lifting eccentric wheel arranged on the main shaft in a sleeving mode, a feed lifting eccentricity adjusting assembly and a feed lifting connecting rod both connected with the main shaft and the feed lifting eccentric wheel, and a feed lifting crank fixed to the feed lifting shaft, one end of the feed lifting connecting rod is rotationally arranged on the periphery of the feed lifting eccentric wheel in a sleeving mode, and the other end of the feed lifting connecting rod is hinged to the feed lifting crank; when the feed lifting height of the feed dog is adjusted, the main shaft is rotated, and feed lifting eccentricity L between a matching center O1 of the feed lifting eccentric wheel and the feed lifting connecting rod and a rotation center O2 of the main shaft is changed through the feed lifting eccentricity adjusting assembly, so that the transmission efficiency between the main shaft and the feed lifting shaft is changed, the feed lifting height of the feed dog is adjusted, and the adaptability of a sewing machine to different sewing materials is greatly enhanced.

Description

technical field [0001] The invention relates to a height-adjustable mechanism for lifting a feeding tooth. [0002] The present invention also relates to a sewing machine comprising the above-mentioned mechanism for adjusting the height of the feeding dog lifting tooth. Background technique [0003] like figure 1 As shown, all kinds of sewing machines currently on the market include a main shaft 100 driven by a main motor, a tooth frame 200, a feed dog 300 installed on the tooth frame 200, and a tooth lifting mechanism connected between the main shaft 100 and one end of the tooth frame 200. 400, and the feeding mechanism 500 connected between the main shaft 100 and the other end of the tooth frame 200, the main shaft 100 drives the tooth frame 200 and the feeding tooth 300 to reciprocate up and down through the tooth lifting mechanism 400, and the main shaft 100 drives the tooth frame 200 through the feeding mechanism 500 Do back and forth reciprocating motion with feeding...

AI Technical Summary

Problems solved by technology

It can be seen that in the prior art, although the height of the feeding teeth is adjusted by changing the installation position of the tooth lifting fork on the tooth lifting shaft, it also changes the feeding pitch of the sewing machine at the same time, which affects the sewing quality.

[0006] In particular, the above-mentioned method of adjusting the tooth lift height cannot increase the tooth lift height of the feed dog without limit. After adjusting the tooth lift height of the feed dog to a certain height, if it continues to increase, such as increasing to Figure 4 The tooth lift height Z in the shown view, at this time, the stitch length of the sewing machine is X, then when the feed dog moves to Figure 4 In the areas P1 and P2, the phenomenon that the feed dog reverses and drags the sewing material back will appear, which will affect the sewing quality and limit the maximum lifting height of the feed dog

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