382results about "Tensioning devices" patented technology

A sewing machine including a needle being supplied with an upper thread, a loop taker which accommodates a bobbin for a bottom thread, and a drive unit, which forces the needle to perform a reciprocating movement. The needle, during its movement and in cooperation with the loop taker, executes a stitch on a sewing material being advanced between the upper thread and the bottom thread. A take-up lever, for each stitch, pulls tight a knot being formed in the sewing material by the upper thread and the bottom thread in cooperation. The sewing machine further includes a thread transfer member supplying the needle with an upper thread with either a thread portioner or a friction braking assembly for friction braking of the upper thread. A switch switches between thread supply with the thread portioner or with the friction braking assembly. A control unit controls the thread supply from the thread portioner or, alternatively, controls the friction braking assembly.

The invention provides a tension disco control device in sewing machines and belongs to the field of mechanical technology. The invention resolves the following problems in tension disco control devices in prior sewing machines: Rather short service life, rather poor working stability and so on. The tension disco control device for sewing machines is arranged on one side of a tension disco; the tension disco comprises a bar body and an upper clamp disk, a lower clamp disk and a spring that are sleeved on the bar body; the control device also comprises a guide bar fixed in a casing and arranged in parallel with the bar body; the guide bar is connected with a push block that can slide vertically along the guide bar; the push block contacts with the upper clamp disk, so that the upper clamp disk can be tightly pressed on the lower clamp disk; the push block is connected with a power device I through a connection link mechanism I; besides, the casing inside is also linked to a rotation shaft; the rotation shaft is fixed with a handling part; the handling part contacts with the external end of a core bar; the handling part is connected with a power divice II through a connection link mechanism II. Due to the two power devices, the control device has advantages of rather long service life, high working stability and diversified operation and etc.