Needle plate device for a zigzag sewing machine

Claim 2

In a zigzag sewing machine comprising a machine bed, a needle bar having a needle, a first device for controlling the oscillating movement of said needle bar and needle, and a second Device for controlling the sewing field position of said needle bar, in combination, a needle plate device comprising a needle plate formed with an elongated slot for the passage of said needle during zigzag stitching and mounted on said machine bed, a plate element slidably mounted on said needle plate for movement to and from a position partly closing said slot so that only an opening for the passage of said needle during straight stitching remains open, operating means controlling said first and second devices and including a manually operated dial and first and second cams, and lever means connecting said operating means with said plate element and including a forked lever and first, second, and third levers.

Claim 3

Needle plate device as set forth in claim 1 comprising a follower member connected with said second device and cooperating with said first cam, and an adjusting plate connected with said first device and adjustably mounted on said forked lever, and cooperating with said second cam.

Claim 4

A needle plate device as set forth in claim 2 wherein said forked lever is formed with an oscillation control arm and an actuating arm, the former being adapted to control the oscillating movement of the needle bar and the latter adapted to actuate said first, second and third levers.

Claim 5

A needle plate device as set forth in claim 1 wherein a projection is formed on said needle plate adjacent to said elongated slot, and a cutout is formed at one end of said plate element so that said cutout may slidably engage said projection and said plate element may be guided by said projection during its sliding movement.

Claim 6

A needle plate device as set forth in claim 4 wherein said plate element is at its one end formed with a hole just for straight line stitching.

Claim 7

A needle plate device as set forth in claim 3 wherein said forked lever operatively actuates said first, second and third levers to slidingly move said plate element.

Claim 8

A needle plate device as set forth in claim 6 wherein said second lever is composed of two members for adjustably obtaining a correct predetermined movement of said plate element.

Claim 9

In a zigzag sewing machine including a needle bar and a needle reciprocable in longitudinal direction for making stitches forming a straight seam, and oscillatable in a transverse direction for making zigzag stitches, in combination, a device for controlling the oscillating movement of said needle bar and needle; a needle plate formed with a transverse slot for the passage of said needle during oscillation and zigzag stitching; a plate element mounted on said needle plate for movement between an inoperative position in which said slot is open, and an operative position partly closing said slot so that only an opening for the passage of said needle during straight stitching remains open; and manually operated means connected with said device for controlling the oscillating movement and with said plate element to simultaneously effect nonoscillation and straight stitching of said needle bar and needle, and positioning of said plate element in said operative position whereby a fabric on said needle plate and needle element cannot be pressed into said slot during straight stitching.

Claim 10

In a zigzag sewing machine including a needle bar and a needle reciprocable in longitudinal direction for making stitches forming a straight seam, and oscillatable in a transverse direction for making zigzag stitches, in combination, a device for controlling the oscillating movement of said needle bar and needle; a needle plate formed with a transverse slot for the passage of said needle during oscillation and zigzag stitching; a plate element mounted on said needle plate for movement between an inoperative position in which said slot is open, and an operative position partly closing said slot so that only an opening for the passage of said needle during straight stitching remains open; and manually operated means connected with said device for controlling the oscillating movement and with said plate element to simultaneously effect nonoscillation and straight stitching of said needle bar and needle, and positioning of said plate element in said operative position whereby a fabric on said needle plate and needle element cannot be pressed into said slot during straight stitching.

Claim 11

In a zigzag sewing machine as claimed in claim 8, in combination, another device for controlling the sewing field position of said needle bar and needle; wherein said manually operated means is connected with said other device for setting said needle bar and needle to a central field position simultaneously with the placing of said plate element in said operative position and with the setting of said needle bar to straight stitching; and wherein said plate element in said operative position covers the ends of said slot and has a central cutout registering with said slot in said operative position and forming said opening in the center portion of said slot.

Claim 12

A zigzag sewing machine as claimed in claim 9 wherein said needle plate has a projection located in said cutout of Said plate element adjacent a transverse edge of said slot, said projection guiding said plate element for movement between said inoperative and operative positions and stopping the same in said operative position.

Claim 13

A zigzag sewing machine as claimed in claim 9 wherein said manually operated means includes a dial knob, and linkage means connecting the same with said devices and said plate element.