US3125049A - Sewing machine - Google Patents

Description

March 17, 1964 H. E. REDMAN SEWING MACHINE Filed Nov. 1, 1962 United States Patent 3,125,049 EWING MACHINE Howard E. Redman, Weymouth, Mass., assignor to United Mattress Machinery Co., Inc., Quincy, Mass., a corporation of Maine Filed Nov. 1, 1962, Ser. No. 234,782 3 Claims. (Cl. 112-184) The present invention relates to improvements in a lock-stitch sewing machine having a pointed thread carrying needle and a rotary hook.

Theinvention is herein disclosed as embodied in a mattress quilt sewing machine of the general type in which a mattress quilt supporting frame is mounted on a carriage assembly for movement with relation to the sewing mechanism for eifecting the feed of the stitching operation over the face of the mattress quilt in any desired direction.

The sewing mechanism comprises an overarm in which is carried a presser foot and a vertically reciprocating thread carrying needle, and an underarm beneath the work in which is housed a rotary looper mechanism including a rotary hook and a bobbin case loosely supported against rotation of the hook. In mattress quilt sewing machines of the type described, considerable difficulty has been encountered in maintaining a close co operation of the needle and rotary hook because of the heavy lateral stresses imposed on the needle shank by the feeding movements of the mattress quilt which may be in any direction in accordance with the dictation of the pattern.

Objects of the present invention are to provide a novel and improved construction of the devices for supporting and guiding the needle and rotary hook mechanism of the machine which will provide for the more effective support of the needle when extended through the work in cooperative relation with the rotary hook and for the more 'efiicient operation of the ortary hook mechanism including the bobbin casing during the loop taking and stitch take-up operations.

In accordance with the invention, the sewing mechanism comprises an overarm in which is supported a vertically reciprocating straight thread carrying needle and an underarm in which is housed a rotary hook supported to turn about a vertical axis, and supporting and guiding devices for the needle and rotary hook mechanism which are rigidly mounted on said underarm to provide an accurate and dependable cooperation of the needle with the rotary hook. The construction and arrangement of the needle guiding devices is such that the needle is positioned positively and accurately with relation to the rotating hook regardless of the direction of feed of the work to insure the accurate and unimpeded forming of the successive stitches by the operation of said devices.

Further in accordance with the invention the supporting and guiding devices insuring the desired cooperation of the straight thread carrying needle and rotary hook include a relatively fixed nylon insert which acts as each successive loop is drawn in during the retracting movement of the needle to absorb the repeated knocking of the bobbin casing against the nylon insert to maintain the casing at all times in a desired angular relation.

With the above and other objects in view as may hereinafter appear the several features of the invention consist in the devices, combinations and arrangement of parts hereinafter described and claimed together with the advantages to be obtained thereby which will be readily understood by one skilled in the art from the following description taken in connection with the accompanying drawings, in which:

FIG. 1 is a sectional view inside elevation of a por- 3,125,049 Patented Mar. 17, 1964 "ice tion of a sewing machine embodying the several features of the invention;

FIG. 2 is a detail plan view taken on a line 22 of FIG. 1 showing the needle, throat plate and rotary hook assembly including the rotary hook and bobbin case mounted therein;

FIG. 3 is a detail sectional view in side elevation taken on a line 3-3 of FIG. 2 but on an enlarged scale to illustrate particularly the relation of the throat plate, needle guide, and rotary hook assembly including the bobbin case;

FIG. 4 is a detail sectional plan view taken on a line 44 of FIG. 3 to illustrate partly the lower rigidly supported needle guide for accurately positioning the needle with relation to the rotary hook;

FIG. 5 is a sectional view in side elevation taken on a line 55 of FIG. 3 illustrating particularly the relationship of the needle guide and the throat plate including the resilient fiber insert for supporting the bobbin casing from oscillation during the formation of successive stitches; and

FIG. 6 is a somewhat fragmentary view similar to FIG. 3 showing the needle in two successive positions during the retracting loop drawing stroke.

The sewing mechanism illustrated in the drawings as embodying in a preferred form the several features of the invention is shown as applied to a machine of the general type having a mattress quilt supporting frame, and a carriage assembly on which the frame and quilt supported thereby are mounted for movement in a plurality of directions for the transfer of the stitching operation over the face of a mattress quilt in accordance with a pattern.

Inasmuch as the mechanism for supporting and feeding the supported mattress quilt is well known in the art and forms specifically no part of the present invention, no further description and illustration thereof is believed necessary.

Referring more specifically to the drawings, the mattress quilt sewing machine illustrated as embodying in a preferred form the several features of the invention comprises an overarm 20 in which is carried a presser foot 22 and a vertically reciprocating thread carrying needle 24. The machine is provided also with an under arm 26 which extends beneath the supported mattress quilt and has mounted therein a rotary hook assembly in cluding a rotary hook 28, a bobbin case 30 and a bobbin 32 supported therein. A removable cover or throat plate 33 attached to the underarm 26 provides an easy access to the rotary hook mechanism, and also as hereinafter set forth provides a means for holding the bobbin case in position, and for guiding the needle as it is driven downwardly through the work to the hook engaging position.

The rotary hook 28, as shown in FIG. 1, is mounted to rotate horizontally about a vertical axis and is mounted for this purpose upon a vertical shaft 34 which is continuously driven from a horizontal drive shaft 36 through bevel gears 38, 40 secured respectively to the shafts 36 and 34.

The rotary hook 28 comprises generally an annulus which has formed therein the hook 42 and is rigidly secured to a base member 44 having a downwardly projecting sleeve socket which is fitted upon and attached to the vertical shaft 34 by means of a pin 46.

The bobbin case 30 and bobbin 32 are loosely supported within the rotary hook element and rest upon two roundheaded buttons forming part of the hook assembly, not shown, to permit a loop of thread to be passed readily around the bobbin passing between the case and the hook assembly including the hook member and base member 44. For holding the bobbin case against rotation a projection 50 is formed on the upper face of the bobbin case and is arranged for engagement between two abutting surfaces 52 and 54 formed on the underside of the throat plate 33 secured to the underarm 26. As hereinafter more fully pointed out in connection with the operation of the device, a nylon insert 58 is supported in a recess formed in the abutment 52 of the throat plate 33 to provide a non-wearing cushion against the repeated knocking of the bobbin case against the abutment 52 which takes place during the formation of each successive stitch. The bobbin case in turn provides support for the bobbin 32 which is mounted on a central pin 69 formed in the bobbin case and is held in position by a tiltable pin locking device 62 of ordinary description.

The needle 24 is formed with an eye 64 through which the needle thread passes, a longitudinally extending groove 66 along which the thread is led from supply to the needle eye, and a fiat face 68 on the opposite side of the needle shank through which the transversely moving rotary hook is passed to engage a portion of the thread extending upwardly along said flat face 68 from the needle eye 64 to the work.

With the present construction an improved needle guiding device is provided to accurately locate the downwardly extended needle with relation to the rotating hook 28 and thus to insure proper engagement of the thread by the hook. During the downward movement of the needle, the pointed end thereof passes first through a bushing 70 mounted in the throat plate 33, said bushing being formed with a rounded inner top edge to engage and guide the needle point through the bushing. Immediately below and separated from the bushing 76 there is provided a needle guide 72 consisting of a block in which is formed a vertically extending bore 74 having an internal diameter slightly greater than the needle 24 so that the needle will be accurately positioned therein with relation to the rotating hook.

The needle guide 72 extends downwardly from an upper level slightly below the underside of the throat plate 33 to a lower level which is near the bobbin 32. A rotary hook receiving cutout 76 is formed in that side of the guide adjacent the rotary hook with the rear face thereof lying in a vertical plane passing through the bore 74 and a forwardly sloping upper face at a level which permits free movement of the rotary hook therebeneath. The needle guide 72 is also formed with a vertically extending slot 78 which opens into the rotary hook facing side of the needle guide 72 and provides passage for the needle thread looped about the rotary hook assembly including the bobbin casing particularly during the retracting movement of the needle. The needle guide 72 is thus provided with an upper portion which substantially encloses the shank of the downwardly moving needle providing a firm support for the needle against displacement in any direction regardless of the direction of feed, and an additional lower portion which provides support for those portions of the needle shank opposite and away from the rotary hook, while free passage is permitted for the rotary hook transversely across the flat face 68 of the needle to receive a loop of the needle thread.

The bobbin thread extends from the bobbin upwardly through an outlet 80 in the bobbin casing above the thread guide 74 through the bushing 70 to the work.

The guiding and supporting devices above described coperate with the needle and rotary hook assembly during each stitch forming cycle in the following manner:

The pointed thread carrying needle during its downward stroke through the work first engages and is guided through the bushing 70 which as shown in the drawing has an aperture of substantially larger diameter than that of the needle and a rounded top surface which will engage with and move the needle, even though it is substantially deflected by the work feed, back into its vertically aligned position. The pointed end of the needle now enters the upper end of the bore 74 formed in the needle guide 72 which accurately positions and supports the needle along its vertical axis against stresses which may be applied in any direction by the continuous feeding movements imparted to the work. As previously noted the bore 74 is completely walled-in at its upper end except for the narrow slot 78 so that the needle is accurately supported and held in position with relation to the rotary hook regardless of the direction of feed and consequent tendency of the needle to be deflected in a corresponding direction.

The arrangement and shaping of the needle guide 72 with relation to the bushing 70 and the rotary hook assembly is well adapted also to insure a maximum of certainty and efliciency in the handling of the needle and bobbin thread.

A slight upward movement of the needle from its extreme low position causes a loop of the needle thread to be thrown out into the path of the shuttle which passes through the cutout 7 6 in the needle guide 72 closely adjacent the flat face 68 of the needle to engage with and pass the said loop around the bobbin casing. Continued upward movement of the needle causes the two legs of the needle loop thus formed to be drawn upwardly through the slot 78 as best shown in FIG. 6. During continued movement of the needle to its high position, the two legs of the needle loop are drawn upwardly through the bushing 70 and through the work, not shown, causing a bight of the bobbin thread to be drawn firmly against the underside of the work to form the next succeeding stitch.

The rotary movement of the rotary hook and the subsequent drawing in of the loop during the retracting movement of the needle causes the bobbin casing to be biased sharply against the nylon insert 58 which acts as a buffer to hold the rotary casing in position against rotation with the rotary hook. The use of the nylon insert 58 has the advantage that no appreciable wear takes place between the adjacent surface of the bobbin casing and the nylon buffer even after an extended period of use. Noise is substantially reduced. The nylon surface also has the advantage that it provides a highly polished, smooth surface past which the loop of thread taken by the looper is drawn with a minimum of friction and resistance.

The invention having been described, what is claimed 1. In a sewing machine having a reciprocating straight needle at one side of the work and a rotary hook assembly at the other side of the work comprising a rotary hook disposed to rotate continuously in one direction about an axis parallel to the needle, and a bobbin case mounted within the hook, the combination of work supporting means including a base, a throat plate mounted in the base having an aperture of a diameter providing a loose fit with the needle to loosely engage and guide the needle below the work level, and a needle guide fixedly supported on said base beneath and separated from said throat plate at one side of the rotary hook shaped to provide a needle receiving bore cylindrically walled-in at its upper end, with a narrow vertical thread receiving slot facing the hook of less width than the diameter of the needle and larger than the diameter of the yarn and opening into said bore through said walled-in portion of the bore, and a rotary hook receiving cutout extending across the rotary hook side of said guide toward the lower end of said bore with the rear face of said cutout lying in a vertical plane passing through said bore, and a forwardly sloping upper portion of said cutout providing surfaces for guiding the needle thread drawn about the rotary hook assembly upwardly through said slot and through the needle eye during the retracting movement of the needle.

2. In a sewing machine having a sewing mechanism including a reciprocating straight needle at one side of the work and a rotary hook assembly at the other side of the work comprising a rotary hook disposed to rotate continuously in one direction about an axis parallel to the needle, and a bobbin case mounted within the hook, and WOIK pporting means including a base, the combination of supporting and guiding devices for said sewing mechanism including a throat plate mounted on said base having formed thereon two abutments separated and facing in opposite directions from one another circumferentially of said rotary hook axis, said bobbin case being formed with faces opposing said abutments, and an insert of a resilient plastic material located between the one of said abutments and opposed face of said bobbin case to arrest rotation of said bobbin case in the direction of rotation of said rotary hook.

3. In a sewing machine having a reciprocating straight needle at one side of the work and a rotary hook assembly at the other side of the work comprising a rotary hook disposed to rotate continuously in one direction about an axis parallel to the needle, and a bobbin case mounted within the hook, the combination of work sup porting means including a base, a throat plate mounted in the base having a bushing to loosely engage and guide the needle below the work lever, and a needle guide fixedly supported on said base beneath and separated from said throat plate at one side of the rotary hook shaped to provide a needle receiving bore cylindrically walled-in at its upper end, with a narrow vertical thread receiving slot opening into said bore through said walled-in portion from the side of said guide adjacent the rotary hook, and a rotary hook receiving cutout extending across the rotary hook side of said guide toward the lower end of said bore with the rear face of said cutout lying in a vertical plane passing through said bore, and a forwardly sloping upper portion of said cutout providing surfaces for guiding the needle thread drawn about the rotary hook assembly upwardly through said slot and through the needle eye during the retracting movement of the needle, said throat plate being formed with two abutments separated from and facing one another circumferentially of said rotary hook axis, said bobbin case being formed with faces opposing said abutments, and in insert formed of a resilient plastic material being provided between one of said abutments and with the opposed face of said bobbin case to arrest rotation of said bobbin case in the direction of rotation of said rotary hook.

References Cited in the file of this patent UNITED STATES PATENTS 983,343 Bayer Feb. 7, 1911 1,162,987 De Voe Dec. 7, 1915 1,413,274 Horat Apr. 18, 1922 1,775,913 Parkes Sept. 16, 1930

Claims (1)

1. IN A SEWING MACHINE HAVING A RECIPROCATING STRAIGHT NEEDLE AT ONE SIDE OF THE WORK AND A ROTARY HOOK ASSEMBLY AT THE OTHER SIDE OF THE WORK COMPRISING A ROTARY HOOK DISPOSED TO ROTATE CONTINUOUSLY IN ONE DIRECTION ABOUT AN AXIS PARALLEL TO THE NEEDLE, AND A BOBBIN CASE MOUNTED WITHIN THE HOOK, THE COMBINATION OF WORK SUPPORTING MEANS INCLUDING A BASE, A THROAT PLATE MOUNTED IN THE BASE HAVING AN APERTURE OF A DIAMETER PROVIDING A LOOSE FIT WITH THE NEEDLE TO LOOSELY ENGAGE AND GUIDE THE NEEDLE BELOW THE WORK LEVEL, AND A NEEDLE GUIDE FIXEDLY SUPPORTED ON SAID BASE BENEATH AND SEPARATED FROM SAID THROAT PLATE AT ONE SIDE OF THE ROTARY HOOK SHAPED TO PROVIDE A NEEDLE RECEIVING BORE CYLINDRICALLY WALLED-IN AT ITS UPPER END, WITH A NARROW VERTICAL THREAD RECEIVING SLOT FACING THE HOOK OF LESS WIDTH THAN THE DIAMETER OF THE NEEDLE AND LARGER THAN THE DIAMETER OF THE YARN AND OPENING INTO SAID BORE THROUGH SAID WALLED-IN PORTION OF THE BORE, AND A ROTARY HOOK RECEIVING CUTOUT EXTENDING ACROSS THE ROTARY HOOK SIDE OF SAID GUIDE TOWARD THE LOWER END OF SAID BORE WITH THE REAR FACE OF SAID CUTOUT LYING IN A VERTICAL PLANE PASSING THROUGH SAID BORE, AND A FORWARDLY SLOPING UPPER PORTION OF SAID CUTOUT PROVIDING SURFACES FOR GUIDING THE NEEDLE THREAD DRAWN ABOUT THE ROTARY HOOK ASSEMBLY UPWARDLY THROUGH SAID SLOT AND THROUGH THE NEEDLE EYE DURING THE RETRACTING MOVEMENT OF THE NEEDLE.

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