US2452167A

US2452167A - Rotary hook

Info

Publication number: US2452167A
Application number: US556723A
Authority: US
Inventors: George R Wainwright
Original assignee: Individual
Current assignee: Individual
Priority date: 1944-10-02
Filing date: 1944-10-02
Publication date: 1948-10-26
Anticipated expiration: 1965-10-26

Description

Patented Oct.. 26, 1948 ROTARY HOOK George R. Wainwright, Glendale, Calif., assignor, by mesne assignments, to William H. Maxwell,

Los Angeles, Calif.

Application October 2, 1944, Serial No. 556,723

8 Claims.

This invention has to do with a rotary hook of a sewing mechanism, that is, with an assembly of elements for handling a bobbin in a lock stitch type sewing machine, and it is a general object of the invention to provide improvements in the mounting of a bobbin case base in a hook unit and an improved arrangement and relationship of hook unit, bobbin case base and thread guard.

Sewing mechanisms or bobbin handling mechanisrns employed in lock stitch type sewing machines involve essentially a hook unit, a bobbin case base, a bobbin case carried by the base and in turn supporting the bobbin proper, and a thread guard. It is advantageous in practice to support the bobbin case base in the hook unit so that there is a certain amount of freedom of movement between these elements and it is also desirable to have the thread guard supported so that it is rigid with the hook unit.

It is a general object of my present invention to provide a structure of the general character hereinabove referred to wherein the bobbin case base is yieldingly supported in the hook unit so that there is a certain limited clearance or freedom of movement between these parts that will free foreign matter that might otherwise tend to jam the mechanism or interfere with free operation.

It is another object of this invention to provide a mechanism of the general character referred to having a yieldingly supported bobbin case base in combination with a thread guard which is rigidly supported from the hook unit. With the construction that I have provided the hook unit supports or forms a base for both the bobbin case base and the thread guard, but the bobbin case base and thread guard are mounted on the hook unit to be entirely independent of each other.

Another object of the present invention is to provide a simplified and improved yielding support for a bobbin case base. The structure of the present invention involves a single spring element which yieldingly retains the bobbin case base in place in connection with the hook unit, this single spring being the only part or element that moves or operates to allow shifting of the bobbin case base relative to the hook unit. By employing a single spring element I obtain a uniform action which is diiiicult, if not impostion will be fully understood from the following i' detailed description of a typical preferred lform and application of the invention, throughout which description reference is made to the accompanying drawings, in which:

Fig. 1 is a side elevation of a mechanism provided by my present invetion. Fig. 2 is a face or front view of the mechanism shown in Fig. l. Fig. 3 is a sectional View taken as indicated by line 3 3 on Fig. 2. Fig. 4 is a transverse sectional view being a View taken substantially as indicated by line 4 4 on Fig. 3. Fig. 5 is an enlarged detailed sectional View showing marginal or flange portions of the hookand the bobbin case base at a point to show the mounting of the guard from the hook unit. Fig. 6 is an enlarged detailed sectional view showing marginal or flange portions ofthe hook unit and bobbin case base at a point to show the manner in which these parts are connected and Fig. '7 is an enlarged detailed sectional View of the connection shown i'n Fig. 6 taken at the screw shown therein and in a direction normal to the plane of Fig. 6. v

The mechanism in which my present invention is incorporated involves, generally, a hook unit A, a bobbin case base B, a bobbin case C, a bobbin D, means E yieldingly retaining the bobbin case base in the hook unit and a thread guardF supported from the hook unit independently` of the bobbin case base and the means EL .These various essential elements are normally assembled together as a unit or mechanism to be carried on the end of a shaft, the bobbincase base being supported in the hook unit, the bobbin case being supported in the bobbin case base B and the bobbin in turn being supported in the case C. The means E serves to yieldingly retain the base B in the hook unit A while the guard F is supported directly on the hook unit A to surround the projecting portion of the bobbin case base without in any way contacting it or interfering with its movement or action.

Since my present invention is primarily concerned with the mounting of the bobbin case base B in the hook unit A through the means E and with the thread guard F and the-manner in which it is mounted on or supported from the hook unit A in relation to the bobbin case base B, I will confine my description largely to these parts or features of the construction and will only make general reference to other structural features of the ymechanism which may, in practice, be features such as are common to' or conventional i mechanisms of this kind.

The hook unit A is the basic part ofthe mechanism and is the member or element by which the mechanism is supported from an operating shaft. In the preferred form, as shown in the drawings, the hook unit involves, generally, a forwardly opening or facing cup-like body I and a mounting hub II. The body I8 includes an inner end wall I2 which projects radially from the forward end of the'hub II and a peripheral side wall 'I3 which projects forward from the outer edge portion or margin of the end I2. The hub Il projects rearwardly from the end I2 and is provided with a central bore I4 to receive an operating shaft and has a tapped opening I5 to carry a set screw for securing the mechanism on a shaft. In addition to the parts thus far described the hook unit includes or is provided with a ange I 6 which projects radially from the rim 'or forward end of the side wall I3, which dange is finished to have a flat smooth forward front face I1. parts ofthe hook unit kare tformed integrally, that isgthey are formed 'as a singlepontinu'ous integral unit, 'as shown throughout the drawings.

The bobbin case' base B isi a cup-liller element supported partially inthe hook unit Ato be concentric therewith and to face forward or in the same direction asthe hook unit. i In its preferred form the bobbin case base involves, generally, an inner end I8, an annular side wall I9 projecting forward from the peripheral edge or margin of I the end wall I8, and a mounting flange projecting radially from the side wall I9. TheI flange 2B of the bobbin'c'ase base is located about midway between the two ends of 'this unit, that is, itis located to project from the middle portion of the side wall I9 and it is lprovided to support the bobbin case base B in or from the hook unit A so that there is a thread passage or channel 2'Iv between these unitsor elements of the mechanism, as lclearly shown in Fig. 3 of the drawings. f

' The bobbin case base B facing downwardly, as above described, forms a receptacle or carrier that receives the Ybobbin case' CY in which the bobbin D is mounted. `The bobbin case C includes, generally, aforward end or flange 22 and 'a rearwardly extending side wall 23 proportioned to Vfit into 4the opening or cavity of the bobbin casebase. The bobbin D is arranged within the case C on a central hub 24 provided in the case 'so that it is confined between 4the wall I8 of the bobbin case base and 'the'wall 2,2 f the bobbin case. Inthe drawings Imhave'shown'a central spindle 25 in the bobbin'case base entering the hub 24 of the bobbin case 'fand in practice any suitable means or mechanism may be incorporated in the structurefor retainingthe parts just described in theproper assembled relationship.

In accordance with the construction that I have provided a recess or channel is provided in the corner formed where the sidewall I3 and flange I6 of the hook unitljoin. This channel 3l] is formed concentric with 4the axis of the 'mechanism and is shaped and proportioned to receive or accommodate the flange 2B of the bobbin case base. The radial extent of the channel is suchas to v receive the flange 20 with working clearance and the depth ori axial extent of the channel'is made substantially equal to the thickness of the flange 20 so that when the bobbin case clase is in thev normal'fposition in the hook u'nitAfthe outer side 3l of the 'flange 20 lies in the same plane as the outer side or face I'I of thenange 16 ofthe hook unit A. The means E In the preferred construction the several L which I have provided for retaining the bobbin case base B in the hook unit A or in other words for retaining the flange 20 in the channel 30 involves a single spring. This spring is a flat or leaf spring arcuate in form, being formed on a center concentric with that of the flange I6 and extending around through an angle of substantially 280. YThe main portion or body 4I] of the leaf spring is proportioned so that it is substantially as wide as the face I1 of the flange I6 between the channel 30 and the outer edge 4I of the flange.

The spring is secured or made fast to the face I1 of the flange I6 at spaced points, preferably at two spaced points as I have shown in the drawings, this being sufcient to hold the spring in place and to gain the action desired as hereinafter described. In the drawings I have shown the spring fastened to the face I1 at two spaced points by means of screws 43 which pass through openings 4d in the spring and thread into tapped openings 45 in the flange, the heads 45 of the screws being engaged over the spring to clamp the spring to the face I1 of the flange.' Where the spring is arcuate, as I have described, and extends through about 280 I can advantageously locate the screws or points of fastening about 65n from the ends of the spring so that they occur about 126 apart. It is to be noted that the spring is mounted -through the screws 43so that the gap or opening between its` two ends occurs opposite or in register with the thread handling parts of the mechanism or, in other words, at the thread channel which enters the hook unit A so that the spring in no way interferes with the threadhandling action of the mechanism.

` In accordance with ymy invention I provide inwardly projecting lips'41 on 4the spring to overhang or overlie the outer side V3l ofthe flange 2001 the bobbin case base. The lips serve to retain the flange 20 in the groove 30 and they are proportioned and locatedon the bod7 IIB of the spring so that they retain `the flange 2IJ'in' the groovel 38 with lthe desired resilience. Where the spring is arcuate and proportioned about as I-have described and `where it is 'fastened at two points, as by two screws 43 as I h'ave`described, I find it practical to provide one lip 4I on the inner edge of the spring between the two 'screws and lips outward of the screws and extending to the ends of the spring. With this arrangement I have three spring lips 4'! retaining the flange 2G in the channel 30 and these lips are spaced around the flange so that the retention is substantially uniform. In practice I may make the spring 4B flat `or I may crimp or corrugate it slightly at each side 0f each screw to give it added resilience orflexibility. lCrimps or bends I8 such as I have just referred to are shown in Fig. 7 of the drawings. I

The thread guard F extends around the front or forward kend portion of the mechanism thus far described, so that itis located in front of the assembled flanges i5 and 20 surrounding the forwardly projecting portion of the bobbin case base B. In the particular form of construction illustrated theV guard, as shown in Fig. 2, is fiat and corresponds generally in size and shape to the flange I6 of the hook unit and has an opening EU sufficiently large to pass the forward or projecting portion of the bobbin case base with clearance. VIn accordance with my invention I support the thread guard F from the ange I6 of the hook unit and Ipreferably provide a plurality of points of support -for the guard so that the guard'is supported firmly in spaced relation immediately forward of or in front of the assembly of the flanges l5 and 2D and the spring of means E.

In the preferred construction I provide three points of support for the thread guard and each of these supports involves a screw 6| carried in an opening 62 in the flange I6 of the hook unit and threaded in an opening 63 in the guard and a spacer in the form of a collar 64 surrounding the screw and bearing between the face Il of the flange i6 and the inner side of the thread guard. The spacer is proportioned to space the thread guard away from the spring of the means E so that there is the desired clearance between these parts, as shown throughout the drawings. The spacers may be separate from the guard or they may be vfastened or joined thereto, in which case they may be threaded so that the screws 6| thread into them, as well as into the guard, as shown in the drawings. The screws 6l enter the openings 62 from the rear face of the ange and their heads 6l are preferably countersunk'into the flange, as shown in the drawings.

In accordance With my invention the mount- X ing of the thread guard from the flange I6 is entirely independent of the support or retention of the flange 2U in the channel (itl. In order to prevent interference between these various elements I provide the spring of the means E with openings 10 which pass the guard supports with clearance, that is` openings suiciently large to pass the spaceres 64 with suitable clearance, as clearly shown in Fig. 5 of the drawings. Where I provide three supports for the thread guard, as shown in the drawings, I locate one midway betweenthe two screws 43 and one at or near each outer end of the spring of means E. This gives the thread guard support at three points about equally spaced around the structure which, in practice, is ample.

In addition to the parts thus far described the mechanism may include features or elements common to this class of mechanism, for instance, at the desired point around the flange l5 it may be fashioned to present a forwardly facing thread engaging tongue 8@ and immediately forward of the tongue in the direction of rotation of the mechanism, the hook unit has an inwardly and rearwardly extending thread passing notch or channel 8l. Further, the thread guard at its inner edge portion may be cut away at 32 and formed to leave a forwardly projecting offset thread engaging tongue 83 which overlies and registers with the tongue 80 of the hook unit and projects from the guard to catch the thread. I'hese various parts may be proportioned or fashioned in the manner common to mechanism of this kind so that they serve or function in the manner common to mechanisms of this character. In like manner the mechanism may include a recessed tongue Si] projecting from the bobbin case base B and a tongue 9i projecting from the bobbin case to cooperate with the tongue 98 and a thread tensioning spring member 92 may be provided in connection with the tongues. In practice these elements can be varied as circumstances require, as my invention is in no way concerned with them but is confined to the features and combinations of construction which I have indicated.

From the foregoing description it will be apparent that I have provided a construction whereby the bobbin case base B is effectively and dependably supported in the hook unit A to cui operate vmost effectively and'yetf lit is yieldingly. held or supported softhat it willwfree vor clear foreign matter that would otherwise tend to jam' the mechanism. .,Likewise, it will be apparent that Ihave provided a construction of the general character referred to having a thread guard of a most advantageous type or form guardingthe structure by which the bobbin case is retainedin the hook unit and that this.,.thread guard is mounted so thatit `is in adenite .predetermined position relative tothehookunit and is-entirely independent-:of.theumounting of the bobbin case base in the hook unit. The thread guardpresents a smooth surface overy which the-thread rolls or slides while being passed aroundfthe bobbin case and provides a guard for the means With thc construction vthat I have provided -I have minimized danger of improper operation due to minor misalignment `of parts. Forv instance. should there be` a slightmisalignment crimperfection in the thread guard it will not `in any way interfere with or'disturb the proper ,action or functioning of the 'bobbincase base and `likewise the bobbin case base is free to function and may clear itself of foreign matter without in any Way interfering with or putting strain upon the thread guard.

It is also to be noted that I have provided a construction whereby the several screws involved can be mounted or set tight to eliminate danger of working loose without danger of binding or setting any of the parts so that their Voperation is impaired.

Having described only a typical preferred form and application of my invention, I do not wish to be limited or restricted to the specific details herein set forth, but wish to reserve to myself any variations or modifications that may appear to those skilled in the art and fall within the scope of the following claims.

Having described my invention, I claim:

1. In a mechanism of the character described, a cup-like hook unit, a bobbin case base supported in the said unit, and a single leaf spring yieldr ingly retaining the said base in the said unit, the

spring being attached to the unit and having circumferentially spaced lip parts projecting from its inner edge yieldingly engaging the base.

2. In a mechanism of the character described, a hook unit, a bdbbin case base supported in the unit, means yieldingly retaining the base in the unit, and a thread guard supported on the unit at the front of the unit opposite said means and l independent of the said means.

3. In a mechanism of the character described, a hook unit having a flange at its forward end, a bobbin case base supported in the unit at the flange, means carried by the flange yieldingly retaining the base in the unit, and a thread guard supported at the forward end of the unit and from the flange independent of said means.

4. In a mechanism of the character described, a hook unit having a flange at its forward end, a bobbin case base supported in the unit at the ange, a leaf spring carried by fthe flange yieldingly retaining the base in the unit, and a thread guard supported at the forward end of the unit and from the ange independent of the said leaf sprlng.

5. In a mechanism of the character described, a hook unit having a ange at its forward end, a bobbin case base supported in the unit at the flange, a leaf spring carried by the flange yieldingly retaining the base in the unit, a Ithread guard at the forward end of the unit free of the base,

attuare? andfsp'aoedsupports mounting the guard Yfrom the flange 'independent cf the? spring.

6;, In a mechanism of the charaote'r'descri-bed, a :liable-unitV having` a. flange at its forward end, a-bobbin'case base supported inthe unit-.at the flange,` a leaf spring carried by the' flange yieldinglyrretaining the. base in the unit, screws xing the spring to the an'ge at spaced points, a thread guard at the'iorward Vend of the unit free of the 'basegandr spaced supports mounting the guard from: the iiange independent of the spring.

7.: In fa" mechanism of the character described, fa hook `unit having a flange at itsforward end, a bobbin case base supported in the' unit at the tlangefa leaf spring vcarried by the ange yieldingiy retaining the base in the unit, a thread guardfat' the forward end of theunit free of the base,and-spaced supports mounting fthe guard from the flange independent of the spring, the spring' having openings passing the said supports with/clearance.

8. In a mechanism of the character described, a. hook-unit-having a flange at its forward encl,v a

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,065,349 Southam et al; Dec. 22, 1936 FOREIGN PATENTS Number Country Date 493,915 Germany Mar. 17, 1930