Abstract: A drop-in pattern stitch assembly for a straight stitch sewing machine comprised of a first drop-in cam drive sub-assembly located at and driven from the forward end of the machine's existing horizontal drive shaft for controlling the lateral zig-zag motion of the machine's needle bar, and a second drop-in cam drive sub-assembly located at and driven from the rearward portion of the horizontal drive shaft for controlling the rotational action of the machine's feed fork regulator, for, in turn, regulating the action of the machine's feed rock unit which moves material on the machine's needle plate. It is contemplated that a standard straight stitch sewing machine can be easily upgraded, first to a simply zig-zag sewing machine, and thereafter to more complex pattern machines, by installation of appropriate drop-in cam drive sub-assemblies of the invention. A special pattern cam belt is adapted for installment between the two in place cam drive sub-assemblies of the invention.

Abstract: A method is disclosed for converting a lockstitch sewing machine to a machine for decorating fabrics with at least one untwisted strand of keratinous fiber applied in a pattern to the fabric. In general, the method consists of removing the throat plate, feed dog, presser foot, bobbin, bobbin case and needle bar from the lockstitch sewing machine and inserting instead a needle block having means for securing a plurality of standard punching needles therein, a throat plate apertured to correspond with the plural punching needles carried by the needle block, a presser foot apertured to correspond with the spacing of the needles in the needle block whether passage of the punching needles therethrough and a presser foot with a guide passage for the fibrous strand and a feeddog with sufficient clearance for the punching needles carried by the needle block.

Abstract: A lock stitching and overlock stitching machine has a primary driving means, a lock stitching device including a drive shaft, an overlock stitching device including a separate drive shaft and being spaced apart from the lock stitching device, the drive shafts of respective stitching devices being coupled to the primary driving means by a clutch means which is operable to rotate the drive shaft of the lock-stitching device in one direction relative to the user and the drive shaft of the overlock-stitching device in an opposite direction relative to the user.

Abstract: A machine body of -shape as viewed in front is formed of a bed, an arm frame laterally disposed above the bed, and an upright support uprightly extended from the bed and supporting one end of the arm frame at an upper end thereof. An upper mechanism of a locking stitching sewing mechanism is disposed in the free end of the arm frame and a lower mechanism of the lockstitching sewing mechanism is disposed below the upper mechanism within the bed so that cloth may be subjected to lockstitching by these mechanisms. An overedge stitching mechanism is provided in a recess within the -shaped body in order to apply overedge to the edge of the cloth.

Abstract: A chainstitch thread guide is formed with a thread guiding trough which extends into a channel on one side of a partitioning wall in a sewing machine to receive needle thread extending upwardly from a tensioning device to a take-up lever and further receives such needle thread extending downwardly from the take-up lever on the way to a sewing needle.

Abstract: A chain stitch conversion throat plate for a lock stitch sewing machine, the throat plate carrying a thread loop retaining pin and a thread stripper device actuated by the up and down motion of the sewing machine feed dog. The thread stripper device includes a block pivotably supporting a wire form having one end for extending beneath the feed dog for up and down motion therewith, and the other end extending adjacent the thread loop retaining pin for stripping the retained loop therefrom on downward motion of the feed dog.

Abstract: A sewing machine having lock stitching device incorporated in a frame and driven by a primary driving member comprising a detachable overlock stitching device having its own needle bar driving mechanism spaced apart from the stitch forming part of the lock stitching device and driven by the same primary driving means. Preferably, a switching mechanism provides for the actuation of one stitching device while the other is at rest.

Abstract: A system is disclosed for minimizing sewing needle breakage on a zig zag sewing machine. A device is included on the sewing machine for sensing the presence of a straight stitch presser foot and, if present, for inhibiting any lateral jogging of the needle bar due to the operator inadvertently selecting a zig zag pattern.

Abstract: The tip end of the upper looper of an edge stitching sewing machine is adapted to have a different profile by engagement with a pawled looper arm provided on the upper looper itself or on a mounting post of the upper looper. When the pawled looper arm is engaged with the upper looper, the sewing machine performs one-needle two-thread edge stitching, while it performs its original one-needle three-thread edge stitching when the pawled looper arm is detached from the upper looper in a disengaged position.

Abstract: An improved mechanism for producing blind stitches with a household sewing machine, including a removable throat plate having a thread deflecting member reciprocatorily driven into engagement with a loop of thread carried by the loop taker to insure engagement of the loop of thread by a hook needle. The thread deflecting member is driven in timed relation to the rising and falling motion of the feed dog by a cam which is fastened to the feed drive shaft.

Abstract: A chain stitch forming device includes a loop retaining member for holding a thread loop having been released from a beak of a loop taker. The loop retaining member is provided at the under side of a restraining member which serves to prevent rotation of a bobbin case retainer and is operated in accordance with a cam surface which is directly connected to a lower shaft of the sewing machine.

Abstract: A work feeding device for sewing machines is disclosed in which an auxiliary feed dog section is constrained closely adjacent to the needle hole on a straight stitch throat plate. The auxiliary feed dog section is formed with surfaces adapted snuggly to embrace at least one limb of a conventional feed dog of the type with wide spread side limbs suitable for accommodating zig-zag stitching. All of the motions are imparted to the auxiliary feed dog section by the conventional feed dog which it embraces.