US 12,281,423 B2
Rotary hook construction for sewing machine and sewing machine
Shinko Egami, Kasugai (JP); Takahiro Yoshida, Kasugai (JP); and Tatsuya Yamashita, Kasugai (JP)
Assigned to TISM CO., LTD., Kasugai (JP)
Appl. No. 18/694,520
Filed by TISM CO., LTD., Kasugai (JP)
PCT Filed Mar. 16, 2022, PCT No. PCT/JP2022/011963
§ 371(c)(1), (2) Date Mar. 22, 2024,
PCT Pub. No. WO2023/053507, PCT Pub. Date Apr. 6, 2023.
Claims priority of application No. 2021-161556 (JP), filed on Sep. 30, 2021.
Prior Publication US 2024/0392485 A1, Nov. 28, 2024
Int. Cl. D05B 57/14 (2006.01); D05B 57/26 (2006.01)
CPC D05B 57/14 (2013.01) [D05B 57/26 (2013.01)] 13 Claims
OG exemplary drawing
 
1. A rotary hook construction for a sewing machine, including a bobbin case rotatably housing a lower thread bobbin having the lower thread wound thereon, an inner rotary hook housing the bobbin case, and an outer rotary hook that rotates around the inner rotary hook in synchronism with an up-and-down movement of a sewing needle, the inner rotary hook having a needle drop hole formed in an upper front surface portion thereof, the outer rotary hook having a hook point member for capturing a loop of an upper thread, the rotary hook construction characterized in that
the inner rotary hook has a recessed portion formed in the upper front surface portion and at a position deviated from the needle drop hole in a rotating direction of the outer rotary hook, the recessed portion opening forward and upward and downward and having a rear wall surface, and that
the bobbin case has a thread take-up member provided thereon for directing the lower thread, paid out from the lower thread bobbin, toward the recessed portion of the inner rotary hook,
wherein the lower thread paid out from the lower thread bobbin within the bobbin case is pulled out upward after passing through a hollow space of the recessed portion by way of the thread take-up member, and
wherein rearward movement of the lower thread passing through the hollow space of the recessed portion is restricted by the rear wall surface of the recessed portion.