US2730978A - Sewing machine - Google Patents

Description

Jan. 17, 1956 w. A. AYRES SEWING MACHINE Filed Jan. 25, 1954 "mm 5 36 INVEN TOR. .95 3.9 38

United States Patent SEWING MACHINE Waldemar A. Ayres, Lakewood, Ohio, assignor to White Sewing Machine Corporation, Lakewood, Ohio, a corporation of Delaware This invention relates to a sewing machine and more particularly to the rotary hook or loop taker mechanism for such a machine.

Ordinary rotary loop takers or hooks include a rotatable cup-shaped body which has a loop seizing beak for manipulating the loop in the upper or :needle thread. The rotary loop taker or hook is located beneath the bed plate of the sewing machine in a location :so that the loop seizing beak. engages the loop of the upper thread when the reciprocating needle has passed through the material being sewed and is beneath the bed plate.

The usual construction includes a bobbin case carrier mounted within the cup-shaped body butheld against rotation therewith or therein and which carrier receives the bobbin case that contains the lower thread bobbin. Suitable means usually carried by the bed plate of the sewing machine cooperates with a portion of the bobbin case carrier to hold the latter, the bobbin case and bobbin against rotation while the rotary hook or loop. taker rotates relative thereto.

Usually the body of the rotary hook is provided with a circular raceway for a peripheral bearing rib on the non-rotatable bobbin case carrier. The body usually has a portion cut away .to form the loop seizing beak and to provide also an opening for the upper or needle loop thread to permit the passage of that side of the loop which is carried to the opposite side of the bobbin case carrier.

The bobbin case carrier usually has a portion of its periphery cut away to provide a similar opening, wherefore the raceway in the body and the bearing rib on the bobbin case carrier are not continuous throughout their circumferences.

In the usual constructions gaps are provided in the cooperating bearing surfaces of the rib and raceway and these gaps can cause what is known as fcloggingf This clogging may cause serious ,difiicultyin the eflicient operation of a sewing machine of this type and can result in temporarily stopping the operation thereof. Clogging will not occur if the upper or needle thread loop is properly or normally formed and the loop seizing beak carries such loop in the correct manner around the bobbin case and bobbin casecarrier. On the other band, should the upper or needle thread loop be improperly formed as, for example, if it should be too slack or if loose threads should accumulate in the vicinity of the loop taker such improperly formed loop or loose threads may be picked up by the loop seizing beak or hook and be drawn between 'the raceway and the body and the peripheral bearing rib on the bobbin case. Under such circumstances it frequently happens that the thread which is improperly drawn into the raceway becomes so tightly wedged therein as to prevent the free and efiicient operation of the loop taker or even to completely stop its operation. When such an occurrence takes place it is necessary usuallyto take the loop taker apart so that the wedged 'thread can be removed from the raceway. This is a serious disadvantage as taking the 2,730,978 Patented Jan. 17, 1956 loop taker :apart ordinarily is a fairly complicated manipulation which the usual "operator is not competent to perform and does not ordinarily have the proper tools for this purpose.

The arrangements heretofore used in loop takers for detachably securing the bobbin case carrier in the rotary body have been extremely complicated and are'difiicult to manipulate in assembling and disassembling the mechamsm.

An object of the present invention is to provide an improved and novel rotary hook or loop taker mechanism .for a sewing machine which can be readily assembled and disassembled by the ordinary operator and which does not require special tools for such operations thus enablingthe operator to readily disassemble and reassemble the mechanism if necessary to clear clogging or for other reasons.

Another object of the invention is to provide an improved and novel rotary hook or loop taker mechanism for a sewing machine wherein the necessity for using both a bobbin case and bobbin case carrier is eliminated and the lower thread bobbin can be mounted directly in the member that usually would be a bobbin case carrier.

Further and additional objects and advantages not hereinbefore referred to will become apparent hereinafter during the detailed description of an embodiment of the invention which is to follow and which embodiment is illustrated in the accompanying drawings forming a part of this specification and wherein,

Fig. l is a plan view on an enlarged scale of a rotary hook or loop taker mounted in a supporting portion of a sewing machine beneath the bed plate.

Fig. 2 is a sectional view taken substantially on line 2-2 of Fig. 1 looking in the direction of the arrows.

Fig. 3 is a partial sectional and partial elevational View taken substantially on irregular line 3-3 of Fig. 1 looking in the direction .of the arrows with the supporting portion of the sewing machine omitted.

Fig. 4 is a detached elevational view of the rotary hook body.

Fig. 5 is a detached plan view of the retainer ring, and

Fig. 6 is a side elevational view of the ring shown in Fig. 5.

Referring to the accompanying drawing, and particularly to Figs. 1 and .2 thereof, it will be understood that a supporting bracket portion of the sewing machine is indicated at 10 and that this portion is located beneath the bed plate of the sewing machine and includes a horizontal arm 11 that underlies the hand hole cover plate of the bed plate and which is located adjacent to but laterally of the path of movement of the vertically reciprocating needle of the sewing machine, all as is well understood in the art.

The horizontal portion 11 is provided on its upper side with an enlarged counterbore 12 which is concentric to and communicates with two smaller counterbores of stepped size, in turn, communicating with a short bore smaller in diameter than any of the counterbores. A hearing bushing 13 has a pressed fit in the stepped counterbores that communicate with the counterbore 12 and the larger end of the bearing bushing 13 extends slightly above the bottom of the counterbore 12.

The body of the rotary hook or loop taker mechanism comprises a circular cup-shaped portion 14 from which extends centrally of the bottom of the cup-shaped por tion a shaft 15 which is either integral with or rigidly connected to the cup-shaped portion 14.

The body is mounted in the support 11, with the portion 14 thereof located in the counterbore 12 and bearing against the upper and larger end of the bearing bushing 13. The body portion .14 is of such size that it can freely rotate within the counterbore and is supported by the bearing bushing 13.

The shaft of the body extends downwardly through the bearing bushing 13 andfhas fixed to it a collar 16 located in the bore of the bracket portion and acting .to maintain the body against axial displacement since the bottom of the portion 14 is held against the larger end of the bearing bushing 13 while .the collar 16 engages the smaller end of said bushing. The shaft 15 extends below the horizontal portion 11 of the bracket portion and is shown as having fixed thereto a bevel gear 17 which meshes with a bevel gear 18 that is fixed to a horizontally extending feed mechanism operating shaft 19, as will be well understood in the art.

The gear ratio is illustrated as imparting two complete revolutions to the body of the rotary hook mechanism for each complete revolution of the shaft 19 as will be well understood. It will be appreciated that the particular gear train operatively interconnecting the rotary hook mechanism with the shaft 19 shown in the drawing is for purposes of illustration and that other types of gear trains for this purpose might be employed.

The cup-shaped portion 14 of the body has its side wail cutaway for a portion of its length as indicated at 20 and is provided adjacent the cutaway part 26 witha loop engaging hook or beak 21 that extends circumferentially of the body and which as the latter rotates counterclockwise will engage the loop of the upper thread as the needle moves through the material and below the bed plate during its reciprocation and passes into the needle opening 22 formed in the horizontal portion 11 of. the bracket, see Figs. 1 and 2.

The cup-shaped body portion 14 is provided internally with an annular shoulder 23 which constitutes a bearing support for the combined bobbin case carrier and bobbin case which will later be described and hereafter will be referred to as the bobbin case.

The wall of the cup-shaped portion 14 of the body above the shoulder 23 and adjacent the outer end of the wall is provided with an annular groove 24 for a. purpose later to be described and which shoulder and groove extend the major portion of the circumference of the or slot 31.for the lower thread from the bobbin that is mounted in the bobbin holder or case, all as will be well understood in the art. In addition, the Wall 29 has fixed thereto an angle bracket 32, the horizontal arm of which projects outwardly of the circumference of the wall and beyond the body and engages in a recess 33 formed in the horizontal portion 11 of the bracket and adjacent to the needle opening 22 therein. 7 a

The bracket 32 and recess 33 in which it engages function to hold the bobbin case or holder against rotation while the body of the rotary hook mechanism rotates relative thereto, it being recalled that the holder or case is supported by the bearing rib 23 of the cup-shaped portion of the body.

The upstanding circular wall 29 has secured to it on its outer side a. thread guiding lug 34 which is usual and which acts to facilitate the passage of the thread over the rotary hook mechanism all as will be well understood. The bobbin holder or case is maintained in proper assembled relationship within the cup-shaped portion 14 of the body of the rotary hook by the simple and novel means now to be described and which means can be readily manipulated by the operator without the necessity of utilizing special tools or the like.

The means referred to comprises a split circular retaining ring 35 and said ring is flat and will be located on the fiat annular shoulder provided radially outwardly of the reduced diameter upstanding circular wall 29 of the bobbin holder or case by the flange 28 as clearly indicated in the body portion 1.4 except of course for that part of the circumference represented by the hook 21 and the cutaway portion 20. j I I The outer or free end of the side wall of the body portion 14 at points circularly spaced thereof is provided with circularly elongated openings 25 and 2b which communicate With the groove 24 with the opening 25 located closely adjacent to one end of the groove while the opening 26 is located inwardly a substantial distance of the other end of the groove.

' The bobbin holder or case (the combined bobbin case carrier and bobbin case or holder) comprises a cup-shaped portion 27 which has a somewhat conical exterior configuration and merges into an annular outstanding bearing rib 28 which when the holder or case is mounted in the cup-shaped portion 14 of the body engages and is supported by the bearing rib 23, it being noted that the bottom of the portion 27 of the bobbin holder or case does not contact the bottom of the cup-shaped portion 14 of the body but that clearance is provided therebetween for the purpose of allowing the lower thread to pass between the'body and the holder or case.

The holder or case above the flange 23 is provided with an upstanding cylindrical wall 29 of reduced diameter which extends above the cup-shaped portion 14 of the body and above the upper side of the horizontal portion 11 of the bracket. The cylindrical wall 29 mounts a tensioning member 3b as will be Well understood in the art and which member is illustrated as similar to the tensioning member shown in my copending application Serial No. 246,437, filed September 13, 1951, and hence need not be further described herein.

The upstanding wall 29 is also provided with an opening drawings, and particularly in Figs. 1 and 3.

The rotary ring adjacent one of its ends, i. e., its upper end as viewed in Fig. 5, is provided on its outer side with a narrow circumferentially' extending rib or lug 36. Also the ring 35 adjacent to but spaced circumferentially from its other end is provided on its outer side with a similar circularly extending rib'or lug 37. The retainer ring 35 intermediate the ribs or lugs 36 and 37 is provided on its outer side with a third circularly extending rib or lug 38 which has a narrow transversely extending slot 39 formed therein intermediate its ends. The retainer ring 35 is positioned on the flange or rib 28 of the bobbin holder or case outside of the upstanding circular wall 29 thereof and in a position such that the rib 36 and the rib 37 pass into the openings 26 and 25, respectively, in the end of the wall of the cup-shaped portion 14 of the body and hence said ribs will line up with the groove 24 in the wall of the'cup-shaped portion of the body. Also at such time the rib'38 of the retainer ring passes into a third opening 40 formed in the end of the wall. of the cup-shaped portion 14 of the body and thus said rib 38 will be aligned with the groove 24.

The retainer ring 35 on its fiat outer side has a cross slot 41 formedtherein intermediate the ribs 36 and 33 and it will be seen that any suitable narrow edged tool can be placed in the slot 41 and the retainer ring mo ed in a counterclockwise direction as seen in Fig. l to cause the ribs 36 and 37 to move in the groove 24 out of alignment with the openings 26 and 25 and in the groove 24 into the dotted line positions of Fig. 1. Also such movement of the retainer ring causes the rib 38 to move in the groove 24out of alignment with the opening 40 and to the dotted line-position of Fig. l. Thus the retainer ring is held against movement axially of the body by the ribs 36, 37Jand 38 being engaged in the groove 24 of the body so that said ring acts to maintain the flange 28 of the bobbin holder or case in engagement with the bearing shoulder 23 of the cup-shaped portion 14 of the body.

In order to prevent undesired circular dispiacement of the retainer ring 35 relative to the body and to cause it to rotate with the body when it has been thus mounted in operative position, the cup-shaped portion 14 of the body is providedwith a double acting spring detent 42 which snaps into the slot 379 of the rib '38 and holds the ring 35 against unwanted angular displacement relative to the body and causes the ring to rotate with the body. However, when the operator desires to displace the retainer ring 35 angularly in a clockwise direction so as to align the ribs 36, 37 and 38 with the openings 26, 25 and 40 in the end of the body wall in order to remove the retainer ring and disassemble the mechanism the pressure exerted on the retainer ring by the tool engaging in the slot 41 will readily overcome the holding action of the detent 42 and permit this to be accomplished.

It will be seen that the operator can readily remove the bobbin case or holder from the body of the rotary hook mechanism merely by removing the retainer ring 35 which is a very simple operation requiring no skill and no special tool. Thus the operator will be able to correct any clogging of the mechanism which might occur and can readily disassemble and reassemble the mechanism whenever the necessity of doing so occurs.

The bobbin for the lower thread which is mounted in the case or holder is indicated at 43 in Figs. 1 and 2. As stated in my copending application Serial No. 246,43 7, filed September 13, 1951, this bobbin may be formed of transparent material and the rotary hook mechanism may be located beneath a transparent window in the hand hole cover of the bed plate, wherefore the operator can visually and readily ascertain the quantity of thread that is on the bobbin.

Although a preferred embodiment of the invention has been illustrated and described herein, it will be understood that the invention is susceptible of various modi fications and adaptations within the scope or" the appended claims.

Having thus described my invention, I claim:

1. A rotary hook mechanism for a sewing machine comprising a rotary hook having a substantially cupshaped body provided internally with an annular bearing shoulder the plane of which is perpendicular to the axis of the hook, said body also being provided in outwardly spaced relation to said shoulder with an annular inwardly facing groove parallel to said shoulder, the outer wall of said groove having a plurality of circularly spaced openings therein communicating with said groove, a bobbin case mounted in said body and having an annular bearing flange supported by said shoulder, a fiat retainer ring mounted on said flange on the side thereof remote to said shoulder, said ring being provided on its circumferential edge with circularly spaced ribs which pass through said openings in the outer wall of said groove and into said groove whereby said ring may be angularly displaced relative to said body in one direction to cause said ribs to move angularly in said groove relative to said openings so as to underlie the outer wall of the groove and interconnect said ring and said body, and means carried by the bobbin case and adapted to engage a stationary portion of the sewing machine to hold the bobbin case against rotation.

A rotary hook mechanism as defined in claim 1 ant wherein one of said ribs on said retaining ring is provided on its outer edge with a notch while said body is provided with a spring detent engaging said notch when said ribs have passed through said openings and are located in said groove by the angular displacement of said ring relative to said body in said one direction whereby said ring and body are interconnected for unitary rotation.

3. A rotary hook mechanism as defined in claim 2 and wherein said ring is a split ring and one of said ribs is located at one end of said split ring, another of said ribs is located circularly inwardly of the opposite end of said ring, and the rib provided. with a notch is located intermediate said two first mentioned ribs, while said ring is provided with a transversely extending tool receiving notch on its outer side.

References Cited in the file of this patent UNITED STATES PATENTS

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