US3386401A

US3386401A - Sewing machines

Info

Publication number: US3386401A
Application number: US439420A
Authority: US
Inventors: Ralph E Johnson
Original assignee: Singer Co
Current assignee: Singer Co
Priority date: 1965-03-12
Filing date: 1965-03-12
Publication date: 1968-06-04
Anticipated expiration: 1985-06-04
Also published as: DE1660986B2; DE1660986A1; BR6677801D0; SE311269B; JPS5318934B1; GB1078796A; CH455468A; SE303420B; GB1078797A; US3379150A

Description

June 4, 1968 R. E. JOHNSON SEWING MACHINES 5 Sheets-Sheet 1 Filed March 12, 1965 Z 'IIIIIIIIIIIL'III.-.

BY Ralph E Johnson V OBNEY R. E. JOHNSON SEWING MACHINES June 4, 1968 5 Sheets-Sheet 2 Filed March 12, 1965 I E yn: Q l, @r 5 E A? 02 a m2 INVENTOR. Ralph E. Johnson WITNESS omvsy' WITNESS BY June 4, 1968 R. E. JOHNSON 3,386,401

SEWING MACHINES Filed March 12, 1965 5 Sheet-Sheefi 3 IN VENTOR.

Ralph E Johnson Malawi 21%;?

June 4, 1968 R. a. JOHNSON SEWING MACHINES 5 Sheets-Sheet 4 Filed March 12, 1965 a m 0 Y E n W 2 .0 E h m 0 R w mm 1 8. 8 l n 7 m mm? M N m W l 7 -5 B n ff mm 1" F H ad :w i W 2' 2 2 a June 4, 1968, R. E JOHNSON 3,336,401

SEWING MACHINES 5 Sheets-Shet 5 Filed March 12, 1965 204 I INVENTOR.

Ralph E. Johnson BY ZII'ORNEY WITNESS United States Patent 3,386,401 SEWING MACHINES Ralph E. Johnson, Boonton, N.J assignor to The Singer Company, New York, N.Y., a corporation of New Jersey Filed Mar. 12, 1965, Ser. No. 439,420 14 Claims. (Cl. 112-484) ABSTRACT OF THE DISCLOSURE A sewing machine is disclosed in which the needle and the loop taker may be operated in an untimed relation yet cooperate in the formation of stitches. Included is a disclosure of a loop taker construction adapted specifi cally for the manipulation of thread in the formation of lock stitches in cooperation with an endwise reciprocatory needle to which movement may be imparted differing in period and phase from that of the loop taker.

This invention relates to sewing machines, and more particularly to a novel construction and arrangement of stitch forming instrumentalities in accordance with my discovery that the stitch forming instrumentalities may be operated successfully in untimed relation.

It is an object of this invention to provide a sewing machine having thread concatenating instrumentalities cooperative in the formation of conventional stitches with each thread concatenating instrumentality operatively associated with individual drive means which operate in untimed relationship.

Another object of this invention is to provide novel sewing machine stitch forming instrumentalities by which cooperation in the formation of stitches is attained in the absence of any predetermined timed interrelationship as between the motions of the thread concatenating instrumentalities.

A further object of this invention is to provide a novel circularly moving loop-taker for a lockstitch sewing machine.

It may be said of all machine-formed stitches that a definite series of essential thread manipulations must occur in the formation of each stitch. The specific essential thread manipulation and sequence thereof will, of course, depend upon the specific type of stitch which is being formed. Where the cooperating thread concatenating instrumentalities comprise, as is conventional, a needle and loop-taker, the aforementioned essential thread manipulations include, generally, the seizure of thread loops by one instrumentality from the other, the manipulation of threads and thread loops, and the shedding of seized thread loops.

In the art of sewing machine stitch forming mechanisms prior to my invention, the attainment of these essential thread manipulations has always entailed the necessity for establishment and maintenance of a predetermined precise timed relation between the operation of the needle and loop-taker. While there has been wide variety as to the particular timed relationship required to be maintained as between various known stitch forming mechanisms, in any given prior art mechanism, meticulous observance of a specific timed relation between needle and loop-taker has heretofore been a prerequisite to successful stitch formation. It will be understood that needle and loop-taker motions of nonuniform velocities Within each recurring cycle of interrelated motions are 3,386,401 Patented June 4, 1968 "ice well known in the prior art. Even in those instances where nonuniform velocities exist as between needle and loop-taker motions, a precise timed relation has heretofore been essential. The term timed relation as used herein refers not to the instantaneous velocity relationships but to the regular recurrence of positional interrelationship as between the needle and loop-taker.

In all prior known sewing machines it has been re quired to impart to the needle and to the loop taker motions having not only precisely related periods, but also motions having predetermined phase relationships within the related periods.

Conversely, the term not in predictably timed relationship as used herein refers to the absence of any predictable relationship in time as between the motion of the needle and the motion of the loop taker. By way of example, in prior art sewing machine in which the needle and loop taker must be operated in timed relationship, knowing the rate at which the needle reciprocation occurs, the rate may be calculated at which each cycle of operation of the loop taker will occur. In the present invention, operation not in predictably timed relationship means that the rate of needle reciprocation cannot be calculated on the basis of a known rate of loop taker rotation. Further, by way of example, in prior art sewing machine in which the needle and loop taker must be operated in timed relationship, knowing the position of the needle in point of time, the corresponding position of the loop taker may be predicted at that same point of time. In the present invention, not in predictably timed relationship means that even knowing the instantaneous rates of motion of the needle and loop taker, the position of the needle in point of time will bear no predictable relationship to the position of the loop taker at that same point of time.

Thus, for example, in mechanisms for forming lockstitches (Federal Stitch Type 301) utilizing a thread carrying needle cooperating with a rotary book, there exist known varieties in which the hook must rotate one revolution for each needle reciprocation. The most prevalent variety of lockstitch sewing machines utilizes a rotary hook which must partake of two revolutions during each needle reciprocation. Also there exist varieties in which the degree of hook rotation required during each needle reciprocation is more than two revolutions, and still others which must include a precise fraction of one complete hook rotation during each needle reciprocation. In each instance, however, a specific timed relation as between the period of needle reciprocation and the period of hook rotation has been required. In addition, predetermined phase relationship within the related periods of needle reciprocation and hook rotation have always heretofore been required.

In the present invention, in addition to the cost savings incident to the elimination of the means for maintaining timed relation between the needle and the loop-taker, additional advantages accrue in the freedom of location and support of the needle and loop-taker which is provided thereby.

The accompanying drawings illustrate a sewing machine embodying a preferred form of my invention in which the thread carrying needle and rotary hook of a lockstitch forming mechanism are operated without regard for any predetermined timed relationship between revolution of the rotary hook and reciprocation of the needle.

In the drawings:

FIG. 1 is a side elevational view of a sewing machine embodying the principles of this invention,

FIG. 2 is an enlarged and exploded perspective view of the work feeding mechanism of the sewing machine illustrated in FIG. 1,

FIG. 3 is a further enlarged perspective view of a portion of the work feeding mechanism illustrated in FIG. 2,

FIG. 4 is an enlarged and exploded perspective view of the needle reciprocating and needle thread take-up mechanisms of the sewing machine of FIG. 1,

FIG. 5 is a vertical cross-sectional view of that portion of the sewing machine of FIG. 1 in the vicinity of the rotary hook taken through the axis of the rotary hook and illustrating the disposition of the sewing threads during work penetration by the needle,

FIG. 6 is a vertical cross-sectional view similar to that of FIG. 5 and illustrating the disposition of the sewing threads after being acted upon by the rotary hook,

FIG. 7 is a top plan view of the parts illustrated in FIGS. 5 and 6 with the sewing threads illustrated in the positions illustrated in FIG. 6,

FIG. 8 is a top plan view of the rotary hook and the surrounding portion of the sewing machine bed but with the work support and the bobbin and bobbin case removed,

FIG. 9 is a top plan view of the bobbin case showing the thread occupying the position illustrated in FIGS. 6 and 7 thereon and including fragments of the rotary hook,

FIG. 10 is a bottom plan view of the bobbin case showing the thread occupying the position illustrated in FIGS. 6, 7 and 9,

FIG. 11 is a vertical cross-sectional view similar to FIG. 5 and illustrating the disposition of the sewing threads shortly after seizure of a needle thread loop by a beak on the loop-taker,

FIG. 11A is a top plan view of the rotary hook, bobbin, bobbin case and fragments of the sewing machine elements associated therewith in a position corresponding to that illustrated in FIG. 11,

FIG. 12 is a vertical cross-sectional view similar to FIG. 11 and illustrating the disposition of sewing threads as the needle thread loop is about to be cast off the rotary hook beak,

FIG. 12A is a top plan view of the rotary hook, bobbin, bobbin case and fragments of the sewing machine elements associated therewith in a position corresponding to that illustrated in FIG. 12,

FIG. 13 is a vertical cross-sectional view similar to FIG. 11 and illustrating the disposition of sewing threads as withdrawal of the needle thread loop from a stored position on the bobbin case is initiated,

FIG. 13A is a top plan view of the rotary hook, bobbin, bobbin case and fragments of the sewing machine elements associated therewith in a position corresponding to thatillustrated in FIG. 13,

FIG. 14 is a perspective view of the top of the bobbin case and,

FIG. 15 is a perspective view of the bottom of the bobbin case.

General organization of machine Referring to FIG. 1 of the drawings, the sewing machine of this invention is assembled preferably on a integral frame indicated generally at 11 and including a horizontal base plate 12 from which extends a vertical standard 13. Secured beneath the base plate 12 as by a bracket 14 and screws 15 is an electric motor 16 having a shaft 17 extending vertically upward through an aperture 18 in the base plate.

A rotary hook indicated generally at 20 is secured as by a set screw 21 to the shaft 17. The rotary hook 20, the specific details of which will be described hereinbelow, is of generally cylindrical form and for protection of a sewing machine operator, is preferably arranged to turn with slight clearance within a bore 22 for-med in a support pedestal 23 fixed as by screws 24 on the base plate 12. A top cover plate 25 seated in a shallow counterbore 26 in the pedestal 23 and secured to the pedestal by

screws

27 and 28 spans the hook accommodating bore 22 and also sustains a raised work supporting plate 29 formed with a needle aperture 30.

As illustrated in FIGS. 5 to 13, a bobbin case indicated generally at rests upon the rotary hook and is both located axially of the hook as well as constrained against rotation with the rotary hook by cooperative interengagement with the top cover plate 25 and with rotation restraining means on the pedestal 23 as will be described with greater particularity hereinbelow together with the details of construction of the bobbin case. A thread carrying bobbin 41 is freely journaled in the bobbin case and held therein by a leaf spring 42 secured by the top cover plate fastening screw 28, which leaf spring also serves to frictionally resist turning movement of the bobbin so as to provide bobbin thread tension.

Referring to FIGS. 1, 2 and 3, a shaft is journaled in the standard 13 and has secured to it a balance wheel pulley 51. An electric motor 52 is supported on a bracket 53 secured on the standard 13 and includes a motor shaft 54 having a pulley 55 fast thereon and drivingly connected as by a belt 56 to the balance wheel pulley 51. As illustrated in FIGS. 2, 3 and 4, turning movement of the shaft 50 serves to impart work penetrating endwise reciprocatory movement to an eye pointed thread carrying needle 57, to impart operative movements to a needle thread take-up mechanism indicated generally at 58, and to operate a work feeding mechanism indicated generally at 59.

A bracket 60 secured by screws 61 to the standard sustains a spool pin 62 and a conventional needle thread tension device 63. These conventional parts are illustrated in FIG. 1 in dot and dashed lines so as not to obscure the other mechanisms of the sewing machine. The path of thread from a spool on the spool pin 62 proceeds to the tension device 63, to the needle thread take-up mechanism 58 and thence to the eye of the needle 57.

Drives Indicated at in FIG. 1 is a receptacle having three

pins

71, 72 and 73. The receptacle 70 is adapted to accommodate a block 74 having three sockets 71', 72 and 73' corresponding to the three receptacle pins. A source of electrical power is indicated in FIG. 1 by the plug 75 adapted to be connected preferably to a supply of alternating current in the conventional fashion and from which two leads 76, 77 are connected to the sockets 71 and 72, respectively.

Two leads 78, 79 connect the receptacle pins 71 and 72, respectively, with the electric motor 16, to the shaft of which the rotary hook 20' is secured. While the motor 16 may be of any known type, in the preferred embodiment illustrated in the drawings the rotary hook drive motor 16 is preferably of the type having substantially uniform speed characteristics such as an induction motor. A toggle switch 80 is included in one of the leads 79 to the motor 16 and provides for that degree of speed control of the hook drive motor which is necessary for practical operation of the sewing machine of this invention.

The electric motor 52 which drives the needle may also be of any known type, but in the embodiment illustrated in the drawings is preferably of a type having readily variable speed characteristics such as a series motor. Leads 81 and 82 directed to the motor 52 are connected respectively to the receptacle pins 71 and 73. Connected to the sockets 72' and 73 respectively of the block 74 are leads '83 and 84 directed to a motor speed control unit 85 which may be of a type adapted to provide operator influenced control of the speed of the motor 52 over a Wide speed range. In the preferred embodiment the motor speed control unit may be of the conventional rheostat type adapted to control the speed of operation of a series motor.

The electric motor 16 and 52 are independent of each other from the standpoint of speed of operation. The motors are not only physically independent but are wired each in association with independent and unrelated motor speed control means 80 and 85.

It will be apparent, therefore, that no precisely predetermined speed ratio would be maintained as between the motors 16 and 52 and that it would be a practical impossibility to operate the motors 16 and 52 in synchronous relation. In other words, the motion imparted by the motors 16 and 52 to the needle and the rotary hook vary in time and cannot recur at regular related intervals of time so that the independent drive means 1 6 and 52 must operate in untimed relationship.

Needle reciprocating mechanism Referring to FIGS. 1 and 4, a cylindrical needle guiding rod is fixed in spaced relation to the standard 13 by means of a support block 91 secured to the standard by screws 92 and engaging the upper extremity of the needle guiding rod.

The split head of an eye bolt 93 having a threaded extremity 94 secured in the standard 13 is provided with a clamp screw 95 which serves to secure the needle guiding rod 90 in the split head of the eye bolt 93 thus to locate the needle guiding rod axially relatively to the standard 13. A slabbed finger 96 formed on the head of the eye bolt is embraced by a guide slot 97 formed in a needle frame 98 slidably journaled on the needle guiding rod. The needle frame 98 is thus slidable along the needle guiding rod 90 but constrained against turning movement thereon by the slabbed finger 96.

At the lower extremity, the needle frame 98 is formed with an oifset needle clamp 99 in which the shank 100 of the needle 57 is fixed. Wire thread guides 101 overlying the needle clamp 99 serve to control the thread which is directed to the needle 57.

At the upper extremity, the needle frame 98 is formed with spaced guide walls 102, 103 defining therebetween a guide slot which extends substantially perpendicular to the needle guiding rod 90 and which accommodates a slide block 104 journaled on a crank pin 105 fixed in a pinion 106 fast on the shaft 50. The slide block 104 and guide slot 102, 103 arrangement thus provides for a scotch yoke drive for imparting work penetrating movement to the needle 57 in response to turning movement of the shaft 50.

T ake-up mechanism Referring to FIGS. 1 and 4, the needle thread take-up mechanism 58 is mounted upon a support plate 110 secured by screws 111 to the standard 13. Pivotally supported on a pivot stud 112 projecting from the support plate 110 is a take-up arm 113 formed with a radially elongated guide slot 114 and having at the free extremity a thread engaging eyelet 115. Journaled on an axle stud 116 secured in the support plate 110 in a counterbalance member 117 carrying a crank pin 118 on which is journaled a slide block 119 arranged in the guide slot 114 of the take-up arm. The counterbalance member 117 is made fast by screws 120 to a pinion 121 which meshes with the pinion 106 on the shaft 50. Preferably the

pinions

106 and 121 are identical in size to provide one take-up oscillation during each needle reciprocation.

Work feeding mechanism and presser device Referring to FIGS. 1, 2 and 3 a presser bar is illustrated having a central portion 131 from the rear of which depends a limb 132 to which a fastening screw 133 secures a shank 134 of a presser foot 135 which overlies the work supporting plate 29 and is formed with a needle aperture 136. Extending upwardly from the front of the central presser bar portion 131 is a bifurcated arm 137 slidably embracing a shouldered guide stud 138 secured in the standard 13. A pivot pin 139 accommodated snugly through an aperture 140 in the central portion 131 of the presser bar 130 is fixed as by a set screw 141 in one arm 142 of a bell crank lever fulcrumed on a pivot stud 143 secured in the standard 13. The other arm 144 of the bell crank

lever

142, 144 underlies a crank pin 145 carried by a stud shaft 146 journaled in the standard 13 to which stud shaft a handle 147 is afi'ixed and by which the bell crank 142, 144 may be rocked so as to raise and lower the presser foot to remove or replace work fabrics thereunder.

Downward pressure is applied to the presser bar by means of a leaf spring 150 anchored in a support stud 151 secured in the standard 13 and notched as at 152 to embrace a tang 153 formed on a connecting element 154. The connecting element 154 is notched as at 155 to embrace a tank 156 formed on a slidingly pivoted link 157 formed at the front extremity with a downturned rounded projection 158 confined within the guide channel formed by upturned lips 159 of a rocking lever 160 pivoted by means of a pin 161 to the central portion 131 of the presser bar 130. The downward pressure exerted by the leaf spring 150 may be regulated by means of an adjusting roller 162 sustained upon the leaf spring by a roller carrying frame 163 which is slidable along a slot 164 in a support bracket 165 secured by screws 166 to the standard 13. A handle 167 associated with the roller carrying frame 163 may be used to selectively adjust the position of the roller along the leaf spring, and the selected position of adjustment is maintained by frictional engagement of the carrier frame 163 with the support bracket 165.

A feed bar 170 is illustrated disposed alongside the presser bar 130. The feed bar is shaped somewhat similar to the presser bar in that it has a central portion 171 from the rear of which depends a limp 172 while from the front an arm 173 extends upwardly and terminates in a bifurcated portion 174. A shank portion 175 of a feeding foot 176 is secured to the depending limb 172 as by a screw 177. The feeding foot 176 is preferably pivotal ly connected to the shank portion 175 and is formed with laterally spaced toe portions 178 disposed one at each side of the presser foot 135.

The feed bar 170 differs from the presser bar 130 first in that an aperture 179 formed in the central portion 171 and embracing the pivot pin 139 is slightly elongated vertically to provide for limited rising and falling movements of the feed bar 170 relatively to the presser bar 130. Second, the central portion 171 of the feed bar is formed with a raised projection 180 upon which the rocking lever 160 can hear when the slidingly pivoted link 157 moves forwardly. Third, the upstanding limb 173 is offset rearwardly and the bifurcated portion 174 embraces a slide block 181 journaled on a pivot pin 182 carried by a connecting link 183 pivotally connected by a pin 184 to a pitman 185. The pitman 185 is formed with a square aperture 186 embracing a feed driving eccentric 187 fast on the shaft 50 and at the other extremity the pitman 185 is pivoted on a pin 188 secured in one extremity of a lever 189 fulcrumed on a shouldered pin 190 secured in the standard 13. A pin 191 pivotally connects the other extremity of the lever 189 with the slidingly pivoted link 157.

The feed driving eccentric 187 imparts both angular oscillatory movement to the pitman 185 about the pin 188 and also oscillatory movement of the pitman in the direction of its length causing oscillation of the lever 189 and consequent endwise oscillation of the slidingly pivoted link 157.

The oscillatory movement of the pitman 185 about the pin 188 by way of the connecting link 183 causes the slide block 181 to traverse the bifurcated portion 174 of the feed bar limb 173. A second slide block 192 journaled on the pivot pin 182 alongside the slide block 181 is seated in a guide slot 193 formed in a block 194 journaled on a stud shaft 195 secured in the standard 13. An operator influenced handle 196 projecting from the block 194 provides means for selectively positioning the block angularly about the stud shaft 195 in any one of a range of positions limited by a stop bracket 197 se cured on the support block 91 for the needle guiding rod and cooperating with an abutment shoulder 198 formed on the block 194.

It will be appreciated that rotation of the eccentric 187 will cause the slide blocks 181 and 192 to rise and fall and alternately cause the slidingly pivoted link 157 to oscillate horizontally carrying the projection 158 back and forth along the guide channel of the rocking lever 160.

Since the slide block 192 is constrained in the guide slot 193, the angular position of the guide slot 193 under the influence of the handle 196 may be regulated relatively to the angular position of the bifurcated portion 174 of the feed bar 170, thus to control the extent of oscillation imparted tothe feed bar 170 by the slide block 181. The oscillatory motion of the feed bar about the pin 139 imparts the feed advance and return motions to the feeding foot 176, and thus the handle 196 serves as a stitch length control element and also as a means for reversing the direction of feed.

The horizontal oscillation of the projection 158 along the rocking lever 160, which occurs alternately with the rise and the fall of the slide block 181, causes the rocking lever 160 to turn about the pivot pin 161 into engagement with the raised projection 180 on the feed bar when the projection 158 shifts forwardly as illustrated in FIG. 2, and causes the rocking lever 160 to turn out of engagement with the feed bar projection 180 when the projection 158 shifts rearwardly over the pivot pin 161 as illustrated in FIG. 3. The pressure exerted by the spring 150 is therefore, applied entirely to the presser bar 130 in the position of parts illustrated in FIG. 3 whereas in the position of parts illustrated in FIG. 2, the spring pressure is applied primarily to the feed bar 170. The direction in which the feeding foot 176 is moved while downward pressure is applied by the rocking lever 160 to the feed bar 170 thus becomes the direction in which work fabrics will be transported, and motion of the feeding foot 176 in the opposite direction which will occur while all spring pressure is removed from the feed bar will result in an idle return motion of the feed dog with the work fabrics being clamped beneath the presser foot 135 to prevent retrograde motion of the work.

The vertically elongate aperture 179 in the feed bar 170 embracing the pin 139 permits limited elevation of the feed bar and feeding foot 176 during return motion thereof when the spring pressure has been removed so that the feeding foot may ride idly over the work fabrics. When the handle 147 is turned, however, the movement of the pin 139 engages the upper surfaces of the apertures 140 and 179 in the presser and feed bars and by virtue of the

bifurcated portions

137 and 174, the presser foot and feeding foot may be elevated together for removal and replacement of work fabrics thereunder.

Loop-taker Referring to FIGS. 1 and 5 through 15, the details of construction of the rotary hook 20, bobbin case 40 and associated mechanisms will now be described.

The rotary hook 20 is formed with a central hub 201 in which the set screw 21 is located and a cylindrical outer wall 202 merging with an inturned flange 203 at the top. The flange 203 is notched radially at intervals as at 204 to form inwardly directed thread seizing beaks 205 on the flange 203. The flange 203 may be formed with one beak 205 or with a plurality of beaks, stitching being possible using the principles of this invention with any number of beaks. As will be explained hereinbelow with reference to the mode of operation of this invention, the number of beaks merely constitutes one factor which may influence the maximum practical speed of needle reciprocation relatively to the speed of rotation of the hook. In the preferred embodiment illustrated in the drawings, four hook beaks 205 are employed and it is also preferable that the diameter of the flange 203 be gradually increased from each beak 205 to the next succeeding notch 204.

The central hub 201 of the rotary hook is formed with a raised boss 206 spaced inwardly of the outer wall 202 to define therebetween an annular recess 207 accommodating penetration of the needle 57. A frusto-conical upper extremity 208 is formed on the raised boss 205 which together with a circular recess 209 formed in the upper end of the raised boss defines a narrow annular land 210 facing upwardly and disposed at a level beneath that of the flange 203 in which the loop seizing beaks 205 are formed.

Referring to FIGS. 7 and 8, a crosspiece 212 is set into the top of the pedestal 23 and is secured by screws 213 so as to span a chord of the rotary hook accommodating bore 22. Secured by screws 214 to the crosspiece is a wire leaf spring 215 having a bowed free extremity 216- projecting beyond the crosspiece. The top cover plate 25 of the pedestal 23 is provided above the bore 22 with a generally rectangular aperture 217 formed with a step 218 adjacent to the needle aperture 30 in the work supporting plate 29. The leaf spring extremity 216 and the step 218 engage the bobbin case 40 to restrain the bobbin case from rotation and to locate the bobbin case relatively to the rotary hook.

The bobbin case 40 is formed with a planar bottom surface 221 from which rises a cylindrical sidewall 222 enclosing a cylindrical upwardly open bobbin accommodating cavity 223 formed concentrically with a cylindrical stud 224 terminating in an upstanding bearing boss 225 on which the bobbin is adapted to be journaled. Projecting radially from the cylindrical sidewall 222 of the bobbin case is :a flange 226 which at its periphery rests atop the rotary hook flange 203 as illustrated in FIGS. 5 and 6. The bobbin case flange 226 is parallel to and spaced from the bottom surface 221 of the bobbin case base so that the surface 221 rests upon the annular land 210 of the raised boss 206 on the rotary hook.

Above the projecting flange 226, the outer surface of the bobbin case sidewall 222 is tapered and frusto-conical in form so as to project through the top cover plate aperture 217 and slightly above the level of the top cover plate 25.

The bobbin 41 is formed with top and bottom flanges 230 and 231 respectively which are preferably formed integrally with a hub portion 232 as illustrated in FIG. 5. The bottom flange 231 is formed with a counterbore 233 which loosely embraces the bobbin case stud 224 and the counterbore 233 terminates in a bore 234 which snugly accommodates the bearing boss 225 on the bobbin case study 224. The leaf spring 42 bears against the top flange 230 of the bobbin and urges a depending peripheral rim 235 on the bottom flange 231 of the bobbin against the bobbin accommodating cavity 223 of the bobbin case to frictionally resist turning of the bobbin, and in addition the spring 42 urges the bobbin case flange 226 against the rotary hook flange 203 and the bottom surface 221 of the bobbin case against the annular land 210 on the raised boss 206 of the rotary hook.

Referring to FIGS. 9, 10, 14 and 15, both the bobbin case sidewall 222 and the projecting flange 226 are cut away along a chord as indicated at 240 which chord faces the path of reciprocation of the needle 57 when the bobbin case is positioned on the rotary hook thus providing needle clearance. Preferably a bevel 241 is formed on the bobbin case base in the vicinity of the cut away portion 240 from the level of the flange 226 to the bottom surface 221 of the bobbin case. Above the level of the flange 226, the sidewall 222 of the bobbin case is vertically slabbed as at 242 substantially parallel to the chord along which the portion 240 is cut away to define a shoulder 243 engageable with the step 218 formed in the top cover plate aperture 217 for restraining rotation of the bobbin case. The bobbin case sidewall 222 adjacent to the shoulder 243 is formed with a vertical slot 244 through which bobbin thread passes to the needle aperture 30 in the Work supporting plate.

The bobbin case sidewall 222 and the projecting flange 226 are also cut away as at 245 along a chord substantially parallel to the crosspiece 212 when the bobbin case is positioned on the rotary hook.

Referring to FIGS. and which illustrate the underside of the bobbin case 40, a shallow recess 256 is formed in the bottom surface 221 of the bobbin case. The recess 250 is partly circular in shape with a chord 251 preferably formed substantially parallel to the cut away portion 245 of the bobbin case sidewall. The recess 250 is preferably formed slightly deeper than the largest diameter of thread which may be handled by the sewing machine and thus the recess serves to provide clearance for movement of the thread between portions of the bobbin case 40 and the annular land 210 on the rotary hook. FIG. 9 includes in dot and dashed lines a representation of the position of the annular land 210 relatively to the bobbin case 40 when the bobbin case is in place on the rotary hook. In FIG. 10, the cross hatched area 210' indicates that portion of the annular land 210 which engages the bottom surface 221 of the bobbin base.

Referring to FIGS. 5, 6, 9 and 14 the frusto-conical outer surface of the bobbin case sidewall 222 is formed near the rim and parallel to the flange 226 with a thread supporting shelf 260 which extends from the slabbed portion 242 adjacent to the path of reciprocation of the needle 57 approximately 180 about the rim of the bobbin case sidewall 222.

Operation With the bobbin case 49 in place on the rotary hook and a bobbin 41 wounnd with thread B in place in the bobbin case cavity 223, the rotary hook may be set in motion by closing the toggle switch 80. As mentioned heretofore, in the embodiment illustrated in the drawings the rotary hook 2t) will preferably be rotated at a substantially constant velocity and in a counterclockwise direction as viewed in FIGS. 7, 8, 11A, 12A, and 13A. The bobbin thread B will not be influenced by the rotating beaks 205 since the bobbin case slot 244 through which the bobbin thread is directed to the needle aperture is situated above the level of the bobbin case flange 226 which rests upon the rotating beaks 205.

In preparation for sewing the needle 57 must carry a needle thread N preferably directed from a spool (not shown) on the spool pin 62 through the needle thread tension device 63, then to the take-up eyelet 115, and finally through the guides 101 and the eye of the needle. Upon insertion of a work fabric beneath the presser and feeding feet, the machine is in readiness to sew.

FIG. 5 illustrates the position of the needle and looptaker parts 'during work penetration of the needle 57 as influenced either by manually turning the balance wheel pulley 51 or by operator influence of the speed control unit 85 for the motor 52. During each work penetration, the needle 57 will move through a range of positions in which the needle thread N carried thereby will be positioned for possible seizure by a beak 205 of the rotary hook. Although the particular range of needle positions during which needle thread loop seizure by the hook beak is possible may vary depending upon many specific factors such as the particular kinematics of the needle reciprocating mechanism, the type of needle, for instance whether scarfed or not, and the condition and type of needle thread and Work fabrics being used, for any given conditions, the particular range is identifiable.

Any of the hook beaks 205 traversing the path of reciprocation of the needle 57 while the needle occupies the thread loop presenting range of positions may seize the presented needle thread loop and carry the seized thread loop into a stored position on the bobbin case 40 as illustrated in FIGS. 6, 7, 9 and 10. FIGS. 11, 11A, 12 and 12A illustrate the manner in which any one of the hook beaks carries the needle thread loop into the stored position on the bobbin case. When seized by any of the hook beaks 205, one limb Ns of the needle thread loop will extend from that beak to the needle eye and the other limb Nw will extend from that beak to the needle aperture 30. Since both thread limbs Ns and Nw extend along chords spanning the circular path of the hook beaks 205, seizure of the needle thread loop by any other hook beak will be obviated. Once seized by any one of the hook beaks 265, that limb Nw of the needle thread loop which extends directly to the needle aperture 30 and to the stitches in the work fabric is carried upwardly through the space provided by the slabbed portion 240 on the bobbin case to the level of the shelf 260 on the bobbin case as illustrated in FIG. 11. That limb of the seized needle thread loop Ns which extends to the eye of the needle and thence to the needle thread supply is carried through the space provided by the slabbed portion 240 and across the underside 221 of the bobbin case.

FIGS. 12 and 12A illustrate the position of parts and of the threads as the hook beak 205 carries the needle thread loop onto the bobbin case 40. It will be noted that the thread limb Nw is deposited on the shelf 260 and the thread limb Ns is carried into the space between the annular land 210 on the rotary hook and the recess 250 in the undersurface of the bobbin case which extends beyond the annular land 210 on that side from which the thread limb Ns is introduced. FIGS. 12 and 12A also illustrate that both thread limbs Ns and Nw are turned about the needle 57 as the thread limbs are drawn out by the hook beak 205. The friction imposed by this turning about the needle coupled with the action of the bobbin case in spreading the thread loop by raising the limb N w above the level of the hook beak and lowering the limb Ns below the level of the hook beak, draws the needle thread loop from the hook beak 255. As illustrated in FIG. 12A the needle thread loop is about to be drawn from the hook beak and as illustrated in FIGS. 6, 7 and 9, the needle thread loop has been drawn from the hook beak and onto the cut away portion 245 of the bobbin case sidewall out of the path of the hook beaks 205.

When the needle thread loop is drawn from the hook beak 295 into the stored position on the bobbin case as illustrated in FIGS. 6, 7 and 9, passage of the thread limb Ns beneath the bobbin case is blocked by that portion 210 of the annular land 210 on the rotary hook which, as illustrated in FIG. 10, engages the underside 221 of the bobbin case beyond the chord 251 of the shallow recess 250 therein.

Once deposited on the bobbin case the thread loop is stored in the sense that further influence by any of the hook beaks is obviated. Thereafter the thread loop is re movable from the bobbin case only in response to further movements of the needle and take-up mechanisms and completely independently of hook rotation. The raising of the needle eye together with application of tension to the needle thread by operation of the needle thread takeup 58 will cause the limb Ns of needle thread which is in the recess 250 beneath the bobbin case to exert a slight upward force on the bobbin case. Moreover, the upward lead of the thread limb Ns to the raised needle eye will carry the thread across the bevel 241 of the bobbin case as well as across the inclination of the slabbed portion 245 of the bobbin case. The combined effect of the upward force applied to the bobbin case together with the camming action of the bobbin case surfaces 241 and 245 will cause the needle thread limb Ns to pass between the bottom surface 221 of the bobbin case and the annular land 210 of the rotary hook boss 206, as indicated by the alternate position marked Ns in FIG. 13A. The needle thread loop is thus freed to pass upwardly about the frusto-conical outer surface of the bobbin case sidewall 222 and upwardly out of the shelf 260 thereon to be drawn over the upper flange 230 of the bobbin 41 between the bobbin and the leaf spring 42 and thence through the needle aperture 30 and into the work fabric. The direction in which the needle thread loop is drawn from the stored position on the bobbin case is upwardly away from the rotary hook beaks and the manipulation of the needle thread loop thus occurs completely about the bobbin 41 within the bobbin case so that a lockstitch thread concatenation is obtained. It will be appreciated that as the needle thread loop is drawn upwardly from stored position on the bobbin case, the needle thread loop will be detained momentarily first by the bowed extremity 216 of the spring 215, then by the leaf spring 42, and finally by the rotation restraining shoulders 213, 243 on the cover plate 25 and bobbin case 40. The needle thread loop is thus controlled during the entire take-up action While the stitch is being set so that the needle thread loop is prevented from accidentally assuming a position in the path of any of the hook beaks 205.

While the above described needle and loop-taker thus cooperate in the formation of stitches in the absence of any predetermined timed relation therebetween, and the ratio of the rates of stitch forming motion of needle and loop-taker may be varied during operation, it may be necessary to limit the maximum speed ratio of needle to loop-taker motion in order that perfect stitching may be attained with certainty.

One such limit of the maximum speed ratio is imposed by the necessity for at least one beak 205 to traverse the path of needle reciprocation within each interval during which the needle occupies the range of positions described above in which needle loop seizure is possible. If, for example, each interval of possible needle loop seizure corresponds to 30 of needle drive shaft 50 rotation, and only one beak 205 is employed, the maximum ratio of needle reciprocation to rotary hook rotation of 1 to 12 ought not to be exceeded if needle loop seizure is to be attained with certainty. The use of a plurality of hook beaks permits the maximum speed ratio to be increased. For instance, in the above example if four hook beaks 205 are employed this ratio limit becomes 1 to 3, and with six such beaks 205 the ratio limit becomes 1 to 2 which is most common in conventional lockstitch forming mechanisms.

While from the standpoint of needle loop seizure there is no theoretical limit to the number of hook beaks which may be employed and, therefore, from the loop seizure standpoint no theoretical limit as to the maximum speed ratio, it will also be appreciated that an ascertainable increment of turning movement of the loop-taker is required in order to position the seized needle thread loop in stored relation on the bobbin case. Since the stored needle thread loop must thereafter be drawn from the bobbin case by the needle and take-up mechanisms before the succeeding stitch concatenation can take place, during which a additional increment of turning movement of the loop-taker will occur, these considerations of thread manipulations will impose a practical limit to the maximum speed ratio attainable regardless of the number of beaks employed.

Although stated hereinabove that the rotary hook is preferably rotated at a constant speed, it will be appreciated that the rotary hook speed may be made variable, provided only that the maximum ratio of speed limits above described are not exceeded. It is an important facet of this invention that should variation of both looptaker and needle reciprocation rates be provided for, synchronism or predetermined correlation as between these rates need not be observed.

Since with this invention a unique cooperating needle and loop-taker arrangement for sewing machines is at tained in which the timed relation, i.e., the positional relation as between the needle and the loop-taker, may

vary at random, it will be appreciated that hitherto unattainable drive means for the needle and loop-taker are now made possible. In the preferred embodiment illustrated in the drawings, for instance, completely separate and unsynchronised electric motors may be used to drive the needle and loop-taker respectively. If, for any reason, it is desired to utilize a single source of power, the drive means for the needle and loop-taker may comprise separate drive trains from the common power source. An important advantage provided by this invention where a common power source is employed is that synchronization is not necessary as between the separate drive trains.

It will also be appreciated that although the principal objects and advantages provided by this mechanism reside in the ability of the needle and loop-taker to cooperate successfully in a synchronous untimed relation, the mechanisms will operate to sew successfully if for any reason provisions are added to drive the needle and loop-taker in synchronism.

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

1. A sewing machine including a reciprocatory thread carrying needle, 2. loop-taker cooperating with said needle in the formation of stitches, and drive means operatively connected not in predictably timed relationship one to said needle and the other to said loop-taker, respectively said loop-taker forming stitches with a needle thread taken from said needle which needle is operated in said not predictably timed relationship with said loop-taker.

2. A sewing machine including a reciprocatory thread carrying needle, a loop-taker cooperating with said needle in the formation of stitches, and separate drive means operatively connected not in predictably timed relationship one to said needle and the other to said looptaker, respectively, said loop-taker forming stitches with a needle thread taken from said needle which needle is operated in said not predictably timed relationship with said loop-taker.

3. A sewing machine including a reciprocatory thread carrying needle, a needle threadtake-up device, means interconnecting-said needle and said take-up device for operation in timed interrelation, a loop-taker cooperating with said needle in the formation of stitches, and drive means operatively connected not in predictably timed relationship one to said needle and the other to said looptaker, respectively, said loop-taker forming stitches with a needle thread taken from said needle which needle is operated in said not predictably timed relationship with said loop-taker.

4. A sewing machine including a reciprocatory thread carrying needle, a needle thread take-up device, a work feeding device, means interconnecting said needle, said take-up device, and said work feeding device for operation in timed interrelation, a loop-taker cooperating with said needle in the formation of stitches, and drive means operatively connected not in predictably timed relationship one to said needle and the other to said loop-taker, respectively, said loop-taker forming stitches with a needle thread taken from said needle which needle is operated in said not predictably timed relationship with said loop-taker.

5. A mechanism for concatenating thread to form stitches comprising a thread carrying needle, a first drive means for imparting endwise work penetrating movement to said needle, a needle thread loop seizing and concatenating device, a second drive means for imparting operative movement to said device, and operator influenced means for controlling the speed of operation of said first and second drive means relatively to each other for varying the speed of operation of said needle and said loop seizing device relatively to each other.

6. A mechanism for concatenating thread to form stitches comprising a thread "carrying needle, a first drive means for a needle thread loop seizing and concatenating 13 device, and a second drive means imparting movement at a substantially constant speed to said needle thread loop seizing and concatenating device, and speed control means controlling said first drive means and providing for any selected needle movement rate unassociated with said second drive means.

7. A mechanism for concatenating thread to form stitches comprising a needle having a thread carrying eye, means supporting said needle for endwise reciprocation in a path including a thread loop presenting portion, a needle thread concatenating device including at least one movable needle thread loop seizing beak, means supporting said thread concatenating device for recurrent movement of said at least one needle thread loop seizing beak in a predetermined path across said thread loop presenting portion of the path of reciprocation of said needle eye, a thread concatenating device drive means imparting a substantially constant rate thereto, a needle reciprocating drive means, and speed control means associated with said needle reciprocating drive means providing for any selected needle reciprocation rate in a range within which said needle eye will occupy said thread loop presenting portion of the path of reciprocation during movement transversely thereof by said at least one needle thread loop seizing beak.

8. A mechanism for concatenating thread to form stitches comprising a needle having a thread carrying eye, means supporting said needle for endwise reciprocation in a path including a thread loop presenting portion, a needle thread concatenating device including at least one movable needle thread loop seizing beak, means supporting said thread concatenating device for recurrent movement of said at least one needle thread loop seizing beak in a predetermined path across said thread loop presenting portion or the path of reciprocation of said needle eye, drive means for reciprocating said needle, drive means for moving said thread concatenating device, and separate unrelated speed control means associated one with the drive means for reciprocating said needle and another with the drive means for moving said thread concatenating device.

*9. A mechanism for concatenating thread to form stitches comprising a needle having a thread carrying eye, means supporting said needle for endwise reciprocation in a path including a thread loop presenting portion, a needle thread concatenating device including at least one movable needle thread loop seizing beak, means supporting said thread concatenating device for recurrent movement of said at least one needle thread loop seizing beak in a predetermined path across said thread loop presenting portion of the path of reciprocation of said needle eye, means for varying the speed ratio of needle reciprocation rate relatively to the rate of operation of said thread concatenating device, comprising drive means for reciprocating said needle, separate drive means for moving said thread concatenating device, and speed control means for operating each of said separate drive means not in predictably timed relationship.

10. A circularly moving loop-taker for a lockstitch sewing machine of the type having a Work penetrating needle cooperating with said loop-taker in the formation of locksti-tche-s and driven in asynchronous relation with said loop-taker, said loop-taker including a cylindrical loop-taker body formed with at least one thread seizing beak, a bobbin case journaled on said loop-taker body, and means for restraining said bobbin case from circular movement with said loop-taker body, the improvement comprising thread loop engaging surfaces formed on said bobbin case to distend needle thread loops seized by said thread engaging beak to that degree necessary to shed said thread loops from said thread seizing beak, thread detaining means formed on said bobbin case for accommodating said shed thread loops out of the path of said thread seizing beak, and means responsive to movement of said needle out of work penetrating position for releasing said thread loop from said thread detaining means.

1 1. A locksti-tch sewing machine having an eye pointed thread carrying needle, means for moving said needle in an endwise reciprocatory path including a lowered thread loop presenting range of positions, a loop-taker having a circularly moving beak, means for imparting loop seizing movement to said beak in a path adjacent to said needle eye and not in predictably timed relationship to said needle motion while said needle occupies said thread loop presenting range of positions, a bobbin case journaled in said loop-taker, needle thread loop deflecting surfaces on said bobbin case to influence needle thread loops seized by said beak to cast from said beak onto said bobbin case, needle thread loop detaining means on said bobbin case for maintaining needle thread loops cast thereon out of the path of movement of said loop seizing beak while said needle occupies said thread loop presenting range of positions, and means responsive to elevation of said needle above said thread loop presenting range of positions for releasing said needle thread loops maintained on said bobbin case by said detaining means.

'12. A locks'titch sewing machine including a work penetrating thread carrying needle, a loop taker cooper-ating with said needle in the formation of stitches, drive means operatively connected in untimed relationship one to said needle and the other to said lo-op taker, said loop taker comprising a right circular cylindrical member formed in one extremity with an annular recess, means supporting said cylindrical member for circular movement about the axis thereof with said annular recess providing clearance for accommodation of said needle during work penetration thereof, at least one radial notch formed in the free extremity of said cylindrical member defining therein a needle thread loop seizing beak, a bobbin case, means sustaining said bobbin case in engagement with said cylindrical member, me'ans restraining said bobbin case from circular movement with said cylindrical member, and cooperating means on said bobbin case and on said cylindrical member eifective to store a needle thread loop on said bobbin case and within the circular path of motion or said loop seizing beak as long as the needle remains accommodated in said annular recess.

13. A lock-stitch sewing machine including a Work penetrating thread carrying needle, a loop taker coop erating with said needle in the formation of stitches, drive means operatively connected not in predictably time-d relationship one to said needle and the other to said loop taker, said loop taker comprising a right circular cylindrical member formed with an axial drive shaft accommodating bore, an annular recess formed in one extremity of said right circular cylindrical member concentrically of said axial bore, an outer cylindrical wall and an inner cylindrical boss defined by said annular recess, said outer cylindrical wall terminating in a right circular rim formed with a radial notch defining a thread seizing beak, and said inner cylindrical boss terminating in a right circular land, a bobbin case journaled in said annular recess, means for restraining said bobbin case from circular movement with said cylindrical member, cooperating means on said bobbin case and on said cylindrical boss effective to store a needle thread loop on said bobbin case, said cooperating means including said bobbin case being formed with a surface contiguous to only a portion of the right annular land of said cylindrical boss, and means biasing said bobbin case surfiace yieldingly into engagement with said portion of said right circular land.

1 4. A lockstitch sewing machine as set forth in claim 16 in which said bobbin case includes a cylindrical bobbin accommodating portion and a bearing flange projecting radially 'from said cylindrical bobbin accommodating portion, and adapted to rest upon said right circular rim of said loop taker, said surface contiguous 15 16 to only a portion of 'said right circular land of said 2,232,692 2/1941 Diehl 112221 cylindrical boss being formed on said cylindricafl bobbin 2,544,227 3/1951 Hohmann '112--184 accommodating portion at one side of 'said bear-ing fi'ange 2,690,724 10/ 1954 Eisenbeiss 112-181 and an annular shelf formed in said cylindrical bobbin 2,750,907 6/1956 'Langhein 112-220 accommodating portion at the opposite side of said 'bea r- 2,966,130 12/1960 John-son 112184 ing flange. 2,985,270 5/1961 Landeros l12219 X Reference: cted FOREIGN PATENTS UNITED STATES PATENTS 537,634 2/1957 Canada. 1,191,160 8/1916 Schoolfield et a1. 112-218 X 1,996,290 4/1935 Gunther 112-228 X 19 HERBERT F. ROSS, Primary Examiner.

2,223,330 11/1940 Naul 112-220