A new thread trimming mechanism and sewing machine

Abstract

The invention provides a novel thread trimming mechanism. The novel thread trimming mechanism comprises a lower shaft, a moving cutter component which can swing around the lower shaft, an eccentric wheel fixedly arranged on the lower shaft, a thread trimming power source, a thread trimming rocking bar which is provided with a fixed swinging pivot point and is driven to act by the thread trimming power source, a first thread trimming swinging rod, a second thread trimming swinging rod, a thread trimming driving connecting rod, a thread trimming shaft as well as a thread trimming driving crank and a thread trimming crank which are respectively fixed at the two ends of the thread trimming shaft, wherein the moving cutter component is provided with at least one moving cutter, the thread trimming rocking bar is hinged with the first thread trimming swinging rod, the second thread trimming swinging rod is hinged with the thread trimming driving crank, the thread trimming driving connecting rod is hinged with the eccentric wheel, the thread trimming driving connecting rod, the first thread trimming swinging rod and the second thread trimming swinging rod are coaxially hinged, and the thread trimming crank is connected with the moving cutter component by virtue of a driving mechanism. The novel thread trimming mechanism provided by the invention has the advantages that the thread trimming rocking bar is driven to act by the thread trimming power source, so as to control a position of a hinge point of the thread trimming rocking bar and the first thread trimming swinging rod, so that the novel thread trimming mechanism is flexibly switched between a non-trimming state and a trimming state, and noise during thread trimming is greatly reduced.

Description

technical field [0001] The invention relates to a garment sewing device, in particular to a novel thread trimming mechanism and a sewing machine. Background technique [0002] At present, sewing machines (especially lockstitch machines) are equipped with an automatic thread trimming mechanism, which is used to cut off the bottom thread and the upper thread at the rotary hook after each sewing. like figure 1 As shown, the automatic thread trimming mechanism in the existing sewing machine generally includes a rotatable lower shaft 100, a first crank shaft 200 parallel to the lower shaft 100 and a second crank shaft 300, and a thread trimming cam 400 installed on the lower shaft 100. , the thread trimming drive assembly 500 installed on the first crankshaft 200, the thread trimming crank 600 installed at one end of the second crankshaft 300, the thread trimming connecting rod 700, the moving knife rest 800, and the moving knife rest 800 fixed The knife 900 and the fixed knife...

AI Technical Summary

Problems solved by technology

[0003] However, the above-mentioned existing automatic thread trimming mechanism has the following defects: 1. The transmission chain is redundant, the structure is complex, and the thread trimming drive assembly and the thread trimming cam crankshaft parts are complicated, and the processing cost is high; 2. When the thread trimming drive assembly drives During the clutching process of the roller and the thread trimming cam, since the speed at which the lower shaft drives the thread trimming cam to run synchronously is very high, there is a certain gap between the roller and the thread trimming cam before they contact and cooperate. There will be a lot of noise at the moment of combination; 3. It needs to be additionally equipped with a spring for reset, which is used to reset the moving parts after thread trimming

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