Upper layer feed mechanism in a sewing machine

In a sewing machine comprising a machine frame, a drive shaft rotatably supported on said machine frame, a horizontal feed adjuster and an eccentric cam mounted on said drive shaft in spaced relationship to each other along the length of the shaft, the eccentricity of said adjuster and eccentric cam with respect to the drive shaft being adjustable, a horizontal feed shaft rockably supported on said machine frame and interlocked to said adjuster and main- and sub-feed dogs disposed on the opposite sides of the cloth feed path in said sewing machine below a cloth being sewn and interlocked to said horizontal feed shaft and eccentric cam for cloth feed movement, characterized by an upper layer feed mechanism comprising a first interlocking arm secured at one end to said horizontal feed shaft, an upper layer feed shaft rotatably supported at one end on said machine frame and having a second interlocking arm secured to the other end, a connector rod connecting between said first and second interlocking arms, an adjusting means adjusting the connection between said second interlocking arm and connector rod with respect to the axis of said horizontal feed shaft and having an adjusting member disposed out of said machine frame, a support arm rotatably supported at one end on said machine frame, an upper feed arm rotatably supported at one end on said support arm and having an upper layer feed dog at the other end above and facing said main feed dog, a connector means connecting between said upper feed shaft and support arm so as to transmit the rocking movement of the upper feed shaft to the support arm to thereby cause said upper layer feed dog to move in the same horizontal plane as said main feed dog, a resilient means normally urging downwardly said upper layer feed dog at said upper layer feed arm and a means rockable in response to the rotation of said drive shaft to cause said upper layer feed dog to raise said upper feed arm against the resiliency of said resilient means when main feed dog descends.