Development Of Automatic Bobbin Changer For Sewing Machine

Lock stitch sewing machines is applied on Flexible intermediate bulk container (FIBC)automatic production equipment to complete the sewing of FIBC. The bobbin case of sewingmachine needs to be changed after a certain working time to keep the supply of lower thread.Currently this job is done by human hands. In order to ensure continuous production of theFIBC equipment, a device must be developed to change the bobbin case of sewing machineautomatically and this is critical in the development of FIBC production equipment.First of all, based on the analysis of hooking mechanism and lock stitch formingprinciple of sewing machine, a research on the motions and steps of automatically bobbinchanging is conducted and a novel method and its technological process is raised. Comparedwith the traditional one, the new method can drop the steps by30%and time by35%.In addition, according to the requirements of FIBC production equipment, the solution ofautomatic bobbin changing device is come up with, which comprises a bobbin changer and afeeding device. The bobbin changer is mounted under the pedestal of sewing machine, whichhas a moving platform. The platform will move out the actuator to finish the bobbin changingonly when it’s needed to. Thus the interference with the production equipment can be avoided.The feeding device has a capacity of72bobbin cases, which are enough for about2.5hours’use by the sewing machine. And the bobbin cases can be easily supplemented into the feedingdevice. With the application of CAD/CAE technology, all the components design and thevirtual assembly of the device are completed.At last, the control system of the device based on PLC is designed, together with thecompletion of control circuit and pneumatic system design and PLC program writing. Theprototype of the device is manufactured and tested, and the design of the device is verified tobe feasible.