Patent ID: 9631304
Date: 2017-04-25
CPC Classifications: D05B

Claim:
1. A variable timing system of a sewing machine, the variable timing system comprising: a shuttle hook having a hook tip; a first helical gear mounted on the shuttle hook; a lower shaft configured to rotate the shuttle hook in synchronization with vertical movement of a needle bar of the sewing machine, wherein the needle bar moves in a range between a top position and a bottom position; a second helical gear mounted on the lower shaft and capable of mesh engagement with the first helical gear, at least one of the first helical gear and the second helical gear being an axially moveable helical gear which is selectively moveable in its axial direction; a control device configured to process data representative of a current sewing situation of the sewing machine and to selectively generate a control signal in response to processing the data; and a drive force mechanism configured to receive the control signal and to transmit axial movement to the axially moveable helical gear in response to the control signal so as to axially move the axially moveable helical gear to one of a plurality of selectable positions provided in a range extending from a first end position to a second end position.