Patent ID: 6668739
Filing Date: 2003-12-30
Classification: D05B

Abstract:
A sewing machine comprising:(A) a lower housing; (B) a first lower rotary shaft disposed in a section of the lower housing and drivingly connected with a power source; (C) a second lower rotary shaft disposed in another section of the lower housing and drivingly connected with a lower stitching needle, the second lower rotary shaft being coaxial with the first lower rotary shaft; (D) a shaft coupler for coupling the first lower rotary shaft with the second lower rotary shaft, whereby the first lower rotary shaft and the second lower rotary shaft are drivingly connected to rotate along with each other; and (E) a looper thread take-up structure fitted on the second lower rotary shaft, the looper thread take-up structure including: (a) a thread guide including a guide plate formed with a slot and two eyelets respectively disposed on two sides of the slot, the guide plate having a fixing slot, a bolt being passed through the fixing slot to lock the guide plate on the lower housing, whereby by means of changing the position of the guide plate relative to the second lower rotary shaft, the positions of the eyelets on two sides of the slot of the guide plate relative to the take-up cam are changeable so as to adjust the take-up timing; and (b) a take-up cam fitted on the second lower rotary shaft and passed through the slot of the guide plate, the take-up cam including a first take-up cam plate and a second take-up cam plate, the first cam plate having an outer circumference and a shaft hole, by means of the shaft hole, the first cam plate being key-fitted on the second lower rotary shaft, the first cam plate being rotatable along with the second lower rotary shaft and axially slidable along the second lower rotary shaft, the second cam plate having an outer circumference and a shaft hole, by means of the shaft hole, the second cam plate being key-fitted on the second lower rotary shaft, the second cam plate being rotatable along with the second lower rotary shaft and axially slidable along the second lower rotary shaft, the first and second cam plates defining therebetween a gap and being separable from each other for easily clearing up tangling thread, a slide interval being defined between the looper thread take-up structure and the shaft coupler, whereby the second cam plate can slide along the second lower rotary shaft to the slide interval and separate from the first cam plate for easily clearing up the tangling thread.