3 - Basic knowledge about the overlock safety stitch machine

Various devices and attachments are available for overlock machines. This issue introduces features of these devices and attachments.

1. Chain-off thread trimming device Many overlock machines are provided with a chain-off thread trimming device. This thread trimming device is provided with lots of features according to processes and applications.

1.1 One-touch type tape cutter and chain-off thread trimming device (T039) ,Automatic tape cutter and chain-off thread trimming device (T040) This type of chain-off thread trimming device is the most frequently used one. The thread trimmer is located at the rear of the throat plate and the knife comes down from above. Because of this mechanism, this thread trimming device is called guillotine type". The one-touch utility type chain-off thread trimming device trims chain-off thread when its switch is pressed. The automatic type is provided with a sensor which detects the beginning and end of sewing and automatically trims chain- off thread when the preset length (the number of stitches) is reached. It is also capable of simultaneously trimming spin tape. Since both of these types of chain-off thread trimming devices drive the knife by means of an electromagnet, the power required for driving the knife is supplied from the sewing machine's own power source. The devices therefore do not need pneumatic piping equipment. As a result, layout changing is very easy. 1.2 Pneumatic flat cutter (T041) This cutter sucks chain-off thread through a chain-off thread suction opening which is located parallel to the throat plate to allow trimming. This cutter is capable of trimming chain-off thread produced on the double chainstitch side of a safety stitch machine. Because of this feature, the pneumatic flat cutter is mainly mounted on the safety stitch machine. 1.3 Pneumatic side cutter (T042) This cutter trims chain-off thread on the side behind the presser foot. The cutter leaves shorter chain-off thread on the material and therefore is suited for blind- hemming and serging of an endless workpiece. It is mainly mounted on the overlock machine. ＊ Since both the pneumatic side cutter and flat cutter pneumatically trim such chain-off thread, they need to be used in combination with a chain-off thread suction unit. 2. Chain-off thread suction device (blower type, pneumatic type) The chain-off thread suction unit is used in combination with a chain-off thread trimming device. 2.1 Blower type (MC-7A) The chain-off thread suction unit sucks chain-off thread by means of a blower motor. It needs no pneumatic piping equipment.

Flat cutter

Side cutter

Basic Knowledge About Overlock/Safety Stitch Machine Various Devices and Attachments | © 2018 Superior Sewing Machine & Supply LLC

2.2 Pneumatic type (MC-4, MC-5, MC-8, MC-24) The chain-off thread suction unit sucks chain-off thread by means of compressed air. Another type which is capable of simultaneously sucking thread chips produced after trimming to help improve the work environment is also available. 3. Auto-lifter (AK32, AK49, AK101) Two different types of auto-lifters are available; one lifts the presser foot by depressing the pedal with the heel in a similar manner to the sewing machines with a thread trimmer and the other lifts the presser foot automatically after thread trimming. Both types help reduce operator fatigue. Since the auto lifter can be mounted on the machine together with a chain-off thread trimming device and chain-off thread suction unit, it helps reduce operator fatigue even more effectively. 4. Gathering device (S159, S160, S161, S162) The gather device is capable of making continuous/partial gathers in knitted fabric, light-weight knit or cloth materials such as georgette and broad cloth. Two different types of gathering devices are available: one opens/closes its gathering foot interlocked with the presser foot pedal and the other opens/closes by means of a manual lever. It has a built-in knee-operated differential feed control device which is used for controlling the differential feed ratio as desired, thereby facilitating partial gathering. In addition, a pedal-interlocked type gathering device for safety stitch machines/overlock machines and a manual-lever type one for safety stitch machines/overlock machines are available. 5. Blind hemming device (L121, L123) The blind hemming ruler is intended for knitted fabric and knits. It helps finish uniformly folded hems, achieving consistent quality. Two different types of rulers are available; one is a simplified type and the other is a stitch failure prevention type, the hemming guide of which moves by a required amount when a multilayered part is reached. 6. Cloth edge guide ruler (H153, H154) The ruler helps produce finished products of consistent quality with its swing- type cloth edge guide which guides the material edge. 7. Tape guide (Q141) This device is best-suited to sewing processes such as sewing shoulder tape to knit products. A consistent finish is promised by using the tape guide in combination with the tape attaching foot. The binder is used for simultaneously run stitching and tape-binding in the reinforcing process for pocket-bag sewing. The binder binds tape while the cut- before knife mechanism of the overlock machine cuts a garment body and the binding tape. The binder is also capable of sewing curved parts of a material to help produce a beautifully finished product. ＊ There are diversified types of overlock/safety stitch machines and their applications are also diverse. We have many more devices which are not introduced in this issue. Please do not hesitate to ask the JUKI office in your area for further information. 8. Binder (N077) Binder for a clean finish at both top and bottom

Pneumatic chain-off thread suction device

Gathering device

Blind hemming device

Binder for a clean finish at both top and bottom

Basic Knowledge About Overlock/Safety Stitch Machine Various Devices and Attachments | © 2018 Superior Sewing Machine & Supply LLC