US3921553A

US3921553A - Lock stitch rotating shuttle

Info

Publication number: US3921553A
Application number: US524864A
Authority: US
Inventors: Kurt Gustmann; Ludwig Sourisseaux
Original assignee: Pfaff Industriemaschinen GmbH
Current assignee: Pfaff Industriemaschinen GmbH
Priority date: 1974-01-25
Filing date: 1974-11-18
Publication date: 1975-11-25
Anticipated expiration: 1992-11-25
Also published as: JPS567252Y2; JPS50107362U

Abstract

A lock stitch rotating thread shuttle comprises a curved shuttle body having a forward oblique edge terminating in a shuttle tip for the thread. A similarly curved thread guide sheet overlies the shuttle body and is secured thereto. Since the forward portion of the shuttle body including the shuttle tip area is of reduced dimension it is spaced from and parallel to a portion of the thread guide sheet. This portion contains a recess and the guide sheet has a tongue portion which projects into this recess. The tongue forms a shoulder for guiding the needle thread after it has been picked up by the shuttle tip.

Description

ited States Patent Gustmann et al.

[ Nov. 25, 1975 LOCK STITCH ROTATING SHUTTLE Inventors: Kurt Gustmann, Kaiserslautern;

Ludwig Sourisseaux, Ramstein, Miesenbach, both of Germany Pfaif Industriemaschinen GmbH, Germany Filed: Nov. 18, 1974 Appl. No.: 524,864

Assignee:

Foreign Application Priority Data Jan. 25, 1974 Germany 7402540[U] US. Cl. 112/228 Int. Cl. D058 57/14 Field of Search 112/228, 232, 181

References Cited UNITED STATES PATENTS 12/1937 Hohmann 112/228 9/1955 Ritter 112/228 X 9/1958 Spaine 112/181 X 3,381,642 5/1968 Bono 112/181 X FOREIGN PATENTS OR APPLICATIONS 1,221,592 1/1960 France 112/232 Primary ExaminerAlfred R. Guest Attorney, Agent, or Firm-McGlew and Tuttle [57] ABSTRACT .which projects into this recess. The tongue forms a shoulder for guiding the needle thread after it has been picked up by the shuttle tip.

2 Claims, 2 Drawing Figures U.S. Patent Nov. 25, 1975 Fig.2

LOCK STITCH ROTATING SHUTTLE BACKGROUND OF THE INVENTION l. Field of the Invention This invention relates in general to the construction of sewing machine shuttles and in particular to a new and useful lock stitch rotating shuttle construction.

2. Description of the Prior Art The present invention deals particularly with the construction of a lock stitch rotating shuttle which includes a guide shoulder providing the shuttle tip for the thread. In the known designs of this kind the guide shoulder is a portion of the shuttle body and it is covered by the thread guiding sheet. In order to prevent the thread from getting clamped between the contact surfaces of the shoulder and the sheet the shoulder wall extending perpendicularly to the orbital plane is inclined in order to urge the thread off the sheet. However in addition it is necessary to prestress and secure the thread guiding sheet so that no gap is formed between the sheet and the contact edge of the guide shoulder. Also these aforementioned conditions can be satisfied only with considerable labor costs and with particular care during the assemblage of the shuttle. The centrifugal force acting on the thread particularly at high sewing speeds tends to press the thread against the shoulder edge contacting the thread guiding sheet. That is why this edge must be sharp and well applying along its entire length. Thus the known design is not only expensive but also susceptible to operational disturbances.

SUMMARY OF THE INVENTION The present invention provides a lock stitch rotating shuttle construction which is an improvement over the known constructions and is less expensive. With the inventive arrangement the guide shoulder for the thread is located on the thread guiding sheet. For this purpose the guide sheet is designed as a guide element which is firmly connected with the thread guiding sheet and has a free end which projects into a recess provided in the shuttle body. Advantageously the guide element is formed by partly cutting out and bending off a portion of the thread guiding sheet.

Accordingly it is an object of the invention to provide a lock stitch rotating thread shuttle which includes a curved shuttle body having a forward oblique edge terminating in a shuttle tip for the thread which has an area adjacent to forward edge of reduced diameter located below a curved thread guide sheet which overlies the shuttle body and which has a tongue which projects into a recess defined in the body.

A further object of the invention is to provide a lock stitch rotating thread shuttle which is simple in design, rugged in construction and economical to manufac- IUI'C.

For an understanding of the principles of the invention, reference is made to the following description of a typical embodiment thereof as illustrated in the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings:

2 FIG. 1 is an exploded perspective view of a rotating shuttle having a thread guiding sheet which is shown separated from the shuttle body and which is constructed in accordance with the invention;

FIG. 2 is an enlarged partial sectional view taken along the line IIII of FIG. 1..

GENERAL DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings in particular the invention embodied therein comprises a lock stitch rotating thread shuttle which includes a shuttle body 1 having a bottom part 2 of a bobbin case which is guided in an annular groove (not shown) of the shuttle body. A bobbin 3 is received in a top part 4 of the bobbin case and it is retained on a pin 6 of the bottom part 2 by means of a lid 5.

The shuttle body 1 includes a peripheral wall having a thick portion 9 and an area of reduced thickness 9a adjacent a forward edge portion. The thicker portion 9 terminates in an edge 8 which is located behind a shuttle tip 7 formed on the forward edge portion 9a. In accordance with the invention, a thread guiding sheet 11 covers the shuttle body over the thicker portion 9 and is secured thereto by screws I0. The forward edge of the guiding sheet 11 terminates in a tip 12 which is positioned approximately at the level of the shuttle tip 7 but laterally thereof. Between the tip 12 and the portion adjacent the edge 8, the thread guiding sheet 11 is provided with a wedge shaped cutout portion 13 leav ing a triangular tongue 14 integral with the sheet. The tongue 14 is bent off at a right angle toward the shuttle center and it projects into a bore or recess 15 which is provided in a forward portion 9a of the shuttle body 1 located behind the shuttle tip 7. The tongue 14 forms a shoulder for guiding the needle thread after the thread has been picked up by the shuttle tip 7 and it is spaced from the shuttle tip by the same distance as is usual for the guide shoulder in a conventional shuttle. The edge 8 is sufficiently spaced from the tongue 14 so that during the sewing operation the needle thread does not come into contact with this edge. The edge 8 is followed on the opposite edge by an oblique edge 16 which extends obliquely to the front side of the shuttle and is also located outside the needle thread path.

While a specific embodiment of the invention has been shown and described in detail to illustrate the application of the principles of the invention it will be understood that the invention may be embodied otherwise without departing from such principles.

WHAT IS CLAIMED IS:

1. A lock stitch rotating thread shuttle, comprising a curved shuttle body having a forward oblique edge terminating in a shuttle tip for the thread, a curved thread guide sheet overlying and secured to said shuttle body, said shuttle body including a forward portion containing said shuttle tip of reduced dimension so that it is spaced from and parallel to an overlying portion of said thread guide sheet, a recess defined in said shuttle body forward portion, said thread guide sheet having a tongue portion projecting into the recess of said shuttle body.

2. A lock stitch rotating thread shuttle according to claim 1 wherein said tongue is formed as an integral cutaway and bent portion of said guide sheet.