US3382826A

US3382826A - Sewing machine loop takers

Info

Publication number: US3382826A
Application number: US537065A
Authority: US
Inventors: Ralph E Johnson
Original assignee: Singer Co
Current assignee: Singer Co
Priority date: 1966-03-24
Filing date: 1966-03-24
Publication date: 1968-05-14
Anticipated expiration: 1985-05-14
Also published as: DE1685011A1; CH461932A; GB1109188A; DE1685011B2

Description

May 14, 1968 R. E. JOHNSON SEWING MACHINE LOOP TAKERS 4 Sheets-Sheet 1 Filed March 24, 1966 Fig.1.

INVENTOR Ralph E. Johnson iTTORNEY witness final/ 14 79;.

y 4 1968 *R. E. JOHNSON 3,382,826

SEWING MACHINE LOOP TAKERS Filed March 24, 1966 4 Sheets-Sheet 2 Fig.2.

INVENTOR. Ralph E. Johnson BY Witness 3 a 14m 76m ATTORNEY May 14, 1968 R. E. JOHNSON SEWING MACHINE LOOP TAKERS 4 Sheets-Sheet 5 Filed March 24, 1966 INVENTOR.

Ralph E. Johnson BY 2T0RNEY May 14, 1968 R. E. JOHNSON SEWING MACHINE LOOP TAKERS 4 Sheets-Sheet 4 Filed March 24, 1966 INVENTOR Ralph E. Johnson 2% A'ATTORNEY Witness flwzzm/ m:

United States Patent 3,382,825 SEWING MACHINE L061 TAKERS Ralph E. .lohnson, Boonton, NJ, assignor to The Singer Company, New York, N.Y., a corporation of New Jersey Filed Mar. 24, 1966, Ser. No. 537,065 6 Claims. (Cl. 112-184) ABSTRACT OF THE DISCLOSURE This invention relates to loop takers for sewing machines and more particularly to a rotary hook construction for a lock stitch sewing machine.

It is an object of this invention to provide a novel and advantageous sewing machine loop taker which is capable of operation in either the conventional timed relation with the sewing machine needle reciprocation or a random or untimed relation with respect to the needle reciprocation.

It is also an object of this invention to provide a novel sewing machine loop taker construction in which the possibility of thread jamming of the loop taker is obviated.

Another object of this invention is to provide a sewing machine loop taker construction in which the thread being manipulated by the loop taker will engage only selected portions of the loop taker which may be manufactured as separate elements and assembled onto a hook body which may be substantially free of highly finished surfaces. With a loop taker construction in accordance with this invention, therefore, the cost and time requirements for loop taker manufacture may be materially decreased.

The novel loop taker of this invention in its details of construction and organization in a sewing machine will now be described with regard to a preferred embodiment ilustrated in the accompanying drawings in which:

FIG. 1 is a front elevaticnal view of a sewing machine including a loop taker constructed in accordance with this invention,

FIG. 2 represents an exploded perspective view of the loop taker including the bobbin case,

FIG. 3 represents a top plan view of the loop taker of this invention as secured in place on the sewing machine of FIG. 1, 7

FIG. 4 is a vertical cross sectional view of the loop taker taken substantially along line 44 of FIG. 3,

FIG. 5 is a top plan view of the loop taker of this invention with the bobbin case removed,

FIG. 6 is a top plan view of the bobbin cas FIGS. 7, 8, and 9 are top plan views of the loop taker including the bobbin case and fragments of the bobbin case restraining means together with a representation of the sewing threads illustrating in FIG. 7 the position of parts as the needle thread loop is seized by the loop taker, in FIG. 8 the position of parts as the seized thread loop is being cast onto the bobbin case, and illustrating in FIG. 9 the stored position of the needle thread loop on the bobbin case, and FIGS. 7a, 8a, and 9a represent vertical cross sectional views of the loop taker taken substantially along lines 7-7, 88, and --9 of FIGS. 7, 8, and 9, respectively.

Referring to the drawings, FIG. 1 illustrates the loop taker of this invention as applied to a sewing machine of ICE the type which is described in detail in my co-pending United States application Ser. No. 524,949, filed Feb. 3, 1966, to which reference may be had. For comprehension of this invention it will be suflicient to understand that the loop taker indicated generally at 11 is carried for circular movement on a bracket 12 which is pivoted on a stud 13 in a loop taker module support plate 14 fixed as by screws 15 to the lower arm 16 of the sewing machine frame 17. Also carried in the sewing machine frame 17 is an endwise reciprocating needle bar 18 carrying an eyepointed thread carrying needle 19, a work feeding mechanism indicated generally at 20, and actuating mechanism for the needle, loop taker, and work feeding mechanism which actuating mechanism includes a rotary shaft 21 carrying a pulley wheel 22 including a pulley 23 adapted to drive the loop taker. The details of construction of the needle supporting mechanism, the work feeding mechanism and the actuating mechanism are fully explained in my above referenced co-pending patent application.

Referring particularly to FIGS. 3 and 4, the loop taker, supporting bracket 12 has fixed to it, as by fastening screw 25, an upstanding cylindrical stud 26. Journaled for turning movement on the cylindrical stud 26, or preferably on a bearing sleeve 27 thereon, is a belt pulley 28 with an upstanding collar portion 29. The loop taker 11 includes an inverted conical body portion 30 which is secured by pins 31 to the upstanding collar portion of the belt pulley. Secured as by a force-fit into a shallow counterbore 32 in the rim of the body portion of the loop taker is a fiat annular ring 33 formed with a plurality of internally extending needle thread loop seizing beaks 34. A pin 35 set into the body portion of the loop taker in the counterbore 32 is accommodated in a peripheral notch 36 in the fiat annular ring 33 and serves to lock the ring for rotation with the body portion of the loop taker. The body portion 30 of the loop taker is preferably conical in form and the converging side walls thereof may be formed with openings 37 to reduce the mass and consequently reduce the inertial of the loop taker.

The bracket 12 upon which the loop taker is journaled is rigidly connected by means of a spacer block 40 to a plate 41 which overlies the loop taker module support p'ate 14. The plate 41 and the bracket 12, which are thus rigidly secured together, provide a swinging frame which is shiftable about the stud 13 so that the loop taker may be swung outwardly to a position in front of the sewing machine for adjustment or the like, and the loop taker may be swung inwardly until a stop lug 42 on the plate 41 abuts one of the fastening screws 15 in which position the needle thread engaging "beaks 34 will travel in sewing position in a path closely adjacent the path of needie reciprocation. A heavy coil spring 43 on the stud 13 includes an arm 44 abutting the sewing machine frame 17 and an arm 45 which bears against the spacer block 49 to bias the loop taker into the sewing position.

Fixedly secured by a screw 50 to the top of the fixed stud 26 is a bobbin case supporting means on tray 51. The tray extends within the body portion 30 of the loop taker and is formed with a flat platform 52 disposed substantially perpendicular to the axis of turning movement of the loop taker body portion 30. Projecting upwardly from the platform are

side walls

53 and 54 arranged substantially at right angles to each other. Indicated generally at 55 is a bobbin case which as shown in FIG. 4 is formed with a bottom surface 56. The bobbin case is complimental to the flat platform 52 and

side walls

53 and 54 of the tray 51. The bobbin case is formed with a peripheral bearing flange 57 extending approximately half way about the bobbin case and as illustrated in FIG. 4 adapted to rest upon the flat upper bearing surface 38 of the flat annular ring 33 on the loop taker body portion when the bottom surface 56 of the bobbin case is accommodated on the platform 52.

The top of the bobbin case is formed with a central circular cavity 58 adapted to accommodate a thread carrying bobbin 59. Preferably the cavity 58 is formed with a central bobbin rotating pin 60 protruding therein and the bobbin 59 is formed with a bore 61 embracing the pin so as to support the bobbin for turning movement relatively to the bobbin case and centrally of the cavity 58. The bobbin case is formed with an inclined thread camming surface 62 which extends from the bearing flange to the mouth of the bobbin accommodating cavity 58. Cut into this inclined thread camming surface near the mouth of the bobbin accommodating cavity 58 is a shelf 63 adapted as will be described hereinbelow to sustain one limb of a needle thread loop in stored position on the bobbin case during stitch formation. A radial opening 64 is formed in the bobbin case leading to the bobbin accommodating cavity 58. This opening 64 not only provides for egress of bobbin thread but also defines an abutment surface 65 on the bobbin case by which positioning of the bobbin case upon the loop taker and restraint of the bobbin case against turning movement with the loop taker is effected. Referring particularly to FIG. 6, the bobbin case on the side opposite that occupied by the bearing flange 57 is slabbed as at 66. Referring to FIG. 3, the plate 41 above the loop taker is formed with an opening 7t) into which the upper portion of the bobbin case projects. A Wire spring 71 secured as by a fastening screw 72; on the plate 41 extends into the opening 70 and abuts the slabbed portion 66 of the bobbin case. A step 73 formed in the opening 70 engages the abutment surface 65 on the bobbin case and the wire spring 71, the step 73, and the

platform side walls

53 and 54 together constrain the bobbin case radially and, angularly, of the loop taker body portion 30.

The bottom surface 56 of the bobbin case is formed with a shallow recess 75 shaped generally circular but with a chord 76 extending across one side. As illustrated in FIGS. 4, 7, 8, and 9, the recess 75 partly overlies the flat platform 52 of the tray 51 so that one limb of each needle thread loop manipulated by the loop taker may enter between the platform 52 and the bobbin case into the shallow recess 75. The chord 76, however, in cooperation with the platform 52 defines a stop for the thread limb maintaining a thread loop in a stored position on the bobbin case during sewing as will be described in greater detail hereinbelow.

Secured by a screw 78 on the plate 41 is a leaf spring 79 which protrudes into the opening 70 of the plate 41 and is formed at the free extremity with a protuberance 80 which bears against the top of a bobbin in place in the bobbin case cavity 58 so as to provide a bobbin thread tension during sewing. The screw 78 also provides for a pivotal axis about which the leaf spring may be turned out of a position overlying the bobbin for ease of exchanging bobbins.

For driving the loop taker an endless belt 99 extends about the loop taker drive pulleys 23 on the pulley wheel 22 and about the belt pulley 28 to which the body portion 30 of the loop taker is made fast. The belt 90 may be directed over

suitable idler pulleys

91 and 92 which may also be adjustably secured to the sewing machine frame 17 so that the requisite belt tension may be obtained. The belt 90 is preferably of circular cross sectional shape and smooth throughout its'length, i.e. without timing logs or clips, since the loop taker of this invention is capable of successful stitch forming operation when operated in an un-synchronized or tin-timed relation to needle reciprocation. As illustrated in the drawings the pulley 23 is approximately three times the diameter of the pulley 28 thereby providing a nominal speed ratio of three revolutions of the loop taker during each reciprocation of the needle. The loop taker of this invention, however, will operate successfully when rotated at a wide range of nominal rates relatively to the needle reciprocation and it has been found that practically any rate from that of slightly greater than one revolution for each needle reciprocation can be made to form stitches satisfactorily. It will be understood, however, that for any particular nominal relation of loop taker rate as compared to needle reciprocation rate the ancillary needle thread controlling devices such as the needle thread take-up may advantageously be selected or adjusted for optimum sewing performance.

Referring to FIGS. 7, 8, and 9, together with the companion FIGS. 7a, 8a, and 9a, the manner in which the loop taker of this invention manipulates needle thread loops to form lock stitches will now be described. As shown in FIGS. 7 and 7a one of the loop seizing beaks 34 on the flat annular ring 33 of the loop taker has seized a loop of thread from the needle 19 which has been reciprocated downwardly through a needle aperture 95 in the plate 41. The seized needle thread loop comprises two limbs of thread extending from the beak 34, a limb NS which extends beneath the beak and leads to the thread supply spool, and a limb NW which extends over the beak and leads to the previous stitch in the work. FIGS. 7 and 7a illustrate that the beak 34 upon seizing a needle thread loop draws the seized loop over the platform side wall 53 and spreads the thread loop over the bearing flange 57 of the bobbin case. The bobbin thread B extends from the bobbin 59 through the radial opening 64 in the bobbin case and the needle aperture 95 in the plate 41 to the previous stitch in the work.

FIGS. 8 and 8a illustrate the disposition of the needle thread limbs NS and NW as the beak 34 carries the needle thread loop about the bobbin case. The work limb of the needle thread loop NW will be urged upwardly along the bobbin case by the thread camming surface 62 thereof and will fall onto the shelf 63. The supply limb of the needle thread loop NS will be drawn between the bottom surface 56 of the bobbin case and the platform 52 and into the shallow cavity beneath the bobbin case which provides clearance for admittance of this supply limb of the needle thread loop.

As the loop taker continues to rotate beyond the position illustrated in FIG. 8 to the position illustrated in FIGS. 9 and 9a the beak 34 will carry the seized needle thread loop to a position beyond the bobbin case bearing flange 57 and onto the slabbed portion 66 of the bobbin case. The wire spring 71 which abuts the slabbed surface 66 of the bobbin case detains the needle thread loop in a position radially inwardly of the path of motion of the beaks 34 on the annular ring 33. The work limb NW of the needle thread loop will rest upon the shelf 63 of the bobbin case and the supply limb NS of the needle thread loop will be detained beneath the bobbin case against the chord 76 of the shallow cavity 53 and in this position of the needle thread loop, as long as the needle remains in the lower portion of its path of reciprocation, the needle thread loo will remain in stored position on the bobbin case completely out of the path of motion of the beaks 34 and thus free of any further influence of the rotating parts of loop taker.

In FIG. 9 the limb of needle thread NS is illustrated in an alternate position in phantom lines which this thread limb NS will assume as the needle 19 is raised on its succeeding up stroke. The upward inclination of the thread limb NS to the needle during this needle up stroke will lift the bobbin case slightly from the platform 52 so as to release the thread limb NS from the restraint of the chord 76. As illustrated in FIG. 9 this chord 76 is preferably oriented substantially parallel to the platform side wall 54 and when the thread limb NS is freed from the restraint of the chord 76 the thread limb NS will be drawn about the slabbed surface 66 of the bobbin case and thereafter the complete needle thread loop NS and NW will be free to be drawn upwardly from the bobbin case through the needle aperture and into the succeeding stitch in the work. The needle thread loop having been manipulated completely about the bobbin case will thus be concatenated about the bobbin thread B and will form a true lock stitch.

FIGS. 7, 8, and 9 illustrate that with the loop taker of this invention the needle thread loops are contacted only by the annular ring 33 of the loop taker body portion and this single part 33 is the only moving element of the loop taker which comes into Contact with the needle thread. The bobbin case 55 is a stationary element and the tray 51 and plate 41 which constrain the bobbin case in position are also stationary elements and although these

elements

41, 51, and 55 contact the needle thread during stitch formation their action upon the thread is not harsh because they are stationary. i;

T he loop taker of this invention provides for appreciable savings in manufacture as compared with conventional loop takers. The fiat annular ring which is the only thread engaging element of the rotating loop taker body portion may be formed as a stamping and finished by relatively straight forward lapping process because of its uniform thickness. The bobbin case is ideally suited for manufacture by a molding process, and the bobbin

case constraining elements

41 and 51 are similarly of uncomplicated design which lend them to convenient manufacture.

Having thus set forth the nature of this invention, what I claim herein is:

1. A circularly moving loop taker for sewing machine, comprising a circularly movable carrier formed with a cavity, means for journalling said carrier relatively to a sewing machine frame, an insert secured on said carrier and formed with a flat bearing surface and with at least one needle loop seizing beak, a bobbin case formed with a flange abutting said flat bearing surface, non-rotating bobbin case constraining means extending within the cavity of said circularly movable carrier and constraining said bobbin case both radially and axially with respect to said carrier, and means for supporting said bobbin case constraining means relatively to said sewing machine frame, said insert, bobbin case, and said bobbin case constraining means being arranged to contact and manipulate needle thread loops seized by said loop seizing beak completely free of engagement with said circularly movable carrier in the formation of stitches.

2. A loop taker as set forth in claim 1 in which said insert comprises an annular ring with flat parallel faces of which one face provides said abutment surface for said bobbin case.

3. A loop taker as set forth in claim 2 in which said annular ring is formed with a plurality of radially inwardly facing needle thread loop seizing beaks.

4. A loop taker as set forth in claim 1 in which said bobbin case constraining means includes a non-rotating bobbin case accommodating platform arranged Within said circularly movable carrier, and in which the support for said platform includes a non-rotating stud extending coaxially of said carrier.

5. A loop taker as set forth in claim 4 in which said bobbin case accommodating platform within said rotary hook beak carrier includes a bobbin case abutting surface disposed substantially perpendicular to the axis of rotation of said carrier and sidewalls projecting from said platform surface contributing to the rotation restraint of said bobbin case.

6. A loop taker as set forth in claim 4 in which said bobbin case provides means for storing a loop of needle thread out of the path of said loop seizing beak, said loop storing means including a shelf formed on said bobbin case for supporting one limb of a needle thread loop, and that portion of said bobbin case accommodated on said platform being formed with a recessed area of which the boundary in cooperation with said platform defines a thread stop supporting the other limb of said stored needle thread loop.

References (Iited UNITED STATES PATENTS 683,847 10/1901 Catenacci et al 1l2-230 1,000,265 8/1911 Hohmann 112181 1,196,160 8/1916 Schoolfield et a1. 112228 X 1,396,040 11/1921 Herr 112-182 1,593,250 7/1926 Echandia 112--220 HERBERT F. ROSS, Primary Examiner.