Patent Abstract:
A single-piece, integral article having spaced parallel, open end prongs frictionally fitted on the prongs of a conventional presser foot on a sewing machine. The article has a pin which, when the article is applied in place, is spaced horizontally from the needle in the sewing machine, and the sewing thread is wrapped around the pin and held from becoming entangled.

Full Description:
FIELD OF THE INVENTION 
     The invention resides in the field of sewing machines where the thread tends to become knotted or tangled, and not run smoothly through the needle. Heretofore thread would often become knotted or entangled, either in association with the needle, or by itself. This was particularly true in the case of metallic thread. Metallic thread easily became knotted, as compared with other threads such as cotton, etc. with corresponding difficulties and annoyances so as to prevent the thread from running smoothly. 
     SUMMARY OF THE INVENTION 
     A main objective of the invention is to provide a guide to overcome the above objection, which can be easily applied to the sewing machine, and that does not require modification of the sewing machine itself to enable its application thereto. 
     The guide is so applied to the sewing machine by fitting it on the presser foot, which includes prongs extending generally horizontally, the guide having corresponding prongs fitted on those prongs. 
     Another object is to provide such a guide that is extremely simple and thereby easily applied to the presser foot of the sewing machine and held thereon mainly by the friction. 
     Still another object is to provide such a guide, whereby when it is applied to the sewing machine, and the thread is put in place in relation thereto, the thread provides a constant pressure to aid in retaining the guide on the presser foot. 
    
    
     BRIEF DESCRIPTIONS OF THE INDIVIDUAL FIGURES OF THE DRAWINGS 
     FIG. 1 is a fragmentary view of a sewing machine to which the guide is applied. 
     FIG. 2 is a fragmentary top view of the prongs of the sewing machine taken at line  2 — 2  of FIG.  1 . 
     FIG. 3 is an end view taken at line  3 — 3  of FIG.  1 . 
     FIG. 4 is a view taken at line  4 — 4  of FIG.  1 . 
     FIG. 5 is a perspective view of the thread guide of the invention. 
     FIG. 6 is a perspective view of the thread guide, but at an angle different from that of FIG.  5 . 
     FIG. 7 is a side view of the thread guide, oriented according to line  4 — 4  of FIG. 1, but omitting the elements of FIG. 4 that are not included in the guide. 
     FIG. 8 is a top view of the thread guide, oriented according to line  8 — 8  of FIG.  1 . 
    
    
     DETAILED DESCRIPTION 
     FIG. 1 shows a fragment of a sewing machine  10  having a needle  12  detachably mounted on a shaft  14 . The shaft, and thus the needle, is mounted vertically, for vertical reciprocation as in known sewing machines. Hereinafter, the sewing machine and the thread guide are described as oriented in FIG. 1, with the needle disposed vertically. 
     The sewing machine has another vertical shaft  16  on which is detachably mounted a presser foot  18  of known kind. This shaft is adjustable vertically between an upper inactive position in which the presser foot is raised, and a lower active position in which the presser foot engages the base  22  of the sewing machine, or any material being sewed. FIG. 2 shows this presser foot in top view, and it will be seen that it includes a pair of spaced prongs  20  disposed generally horizontally, with a space  21  therebetween. These prongs are not truly horizontal, since usually they are curved, but the shape and arrangement is such that they extend generally along the surface of the base  22  or bottom element of the sewing machine. 
     At the beginning of a stitching step, the operator adjusts the shaft  16  downwardly to position the presser foot in its lower, active position, and it remains in that position throughout a predetermined period of stitching. The needle  12  is arranged to extend through the space  21  of the presser foot. The operation of the needle and the presser foot does not require detailed description, and emphasis is placed on the construction of the thread guide itself, which is identified  24 . In the description next following, it will be seen that the device is applied directly to the presser foot and supported thereby. 
     Reference is made to FIGS. 3 and 4 showing the thread guide  24  in its entirety, which is in the form of an attachment, as described in detail hereinbelow. The device includes a main body  26  and a guide pin  28 . The main body includes a shank  30  and a pair of prongs  32 . 
     When the device  24  is fitted on the prongs of the presser foot, the shank  30  extends generally upwardly, but at an oblique angle, and the prongs  32  extend generally horizontally. This main body is of a one-piece, integral construction, the shank being flat and blade-like, and the prongs, while extending generally horizontally, have a vertical dimension or extension  34  (FIG.  4 ), with a space  36  between the prongs. These prongs are parallel, having longitudinal groves  38 , on the inner, or opposing, surfaces, the groves opening out through the free ends of the prongs. 
     The elements are so arranged, that the shank  30 , and the prongs  32 , lie in planes generally perpendicular to a line  40  about which the angle between the shank and the prongs is determined, thereby providing great strength in the appropriate direction for performing a secure guiding function when the device is applied to the sewing machine. 
     The  28  includes a central pin element  42  rigidly mounted on the shank  30  by suitable means indicated  44 . A roller  46  is rotatably fitted on the pin element  42  and rotates to accommodate the thread which is guided around this roller. 
     To apply the guide to the sewing machine, the prongs  32  on the guide are moved longitudinally, to the right, FIG. 1, onto the prongs  20  of the presser foot. The outer free ends of the prongs  20  fit into the groves  38  in the guide prongs  32 . The prongs  32  and the groves  38 , are so dimensioned that the prongs  20  fit in the groves with a high friction fit, for holding the device in place. The guide attachment is applied by merely pushing it onto the presser foot, and removed by simply pulling it off. The thread guide is supported substantially entirely by the presser foot, although as referred to again hereinbelow, the thread in the sewing machine incidentally works in that direction also. 
     As indicated above, the presser foot is generally horizontal, and thereby the prongs  32  are generally horizontal, although not necessarily exactly so. The needle  12  is on a vertical axis line  48 , and when it is reciprocated it passes through the space  21  in the presser foot, and thereby necessarily through the space  36  (FIG. 5) in the attachment. It will be observed that when the guide is applied, the pin is spaced horizontally a substantial distance from the needle, as shown by the spacing  49  in FIG.  1 . 
     FIG. 1 shows the sewing thread  50 , which is to be guided by the guide. This thread leads from a source indicated diagrammatically at  52  in a known manner in present sewing machines, and then it is wrapped over the pin  28  of the attachment, and specifically around the roller  46 . This thread may be wrapped completely around the pin to assure its not being accidentally lifted off of the pin. The thread then leads to the needle at  54  and is threaded therethrough in the usual manner. 
     For convenience in referring to the assemblage of the needle, presser foot and thread guide, the needle and presser foot are at an inner end, and the upper end of the thread guide (pin  28 ) at an outer end. 
     The two lengths  50   a ,  50   b , of the thread  30 , at the pin  28 , are held out away from the needle (FIG. 1) and this prevents that portion of the thread from being tangled or snagged by the needle. As will be understood, the thread, as it is being fed in a sewing step, as oriented in FIG. 1, is pulled away from the needle, to the right, by the material being sewed at the bottom of FIG. 1, and thereby the upper and lower lengths  50   a ,  50   b , are taut. This pulling action to the right, on the thread in the sewing step, pulls the thread in the same direction, and thereby pulls the guide in the same direction, so that the guide is prevented from being dislodged, which would be to the left. 
     For convenience, and particularly in interpreting the claims, the presser foot prongs may be referred to as first prongs, and the thread guide prongs  32  as second prongs.

Technology Classification (CPC): 3