US3051107A

US3051107A - Zigzag sewing machines

Info

Publication number: US3051107A
Application number: US4430A
Authority: US
Inventors: Ralph E Johnson
Original assignee: Singer Co
Current assignee: Singer Co
Priority date: 1960-01-25
Filing date: 1960-01-25
Publication date: 1962-08-28
Anticipated expiration: 1979-08-28

Description

Aug. 28, 1962 R. E. JOHNSON 3,051,107

ZIGZAG SEWING MACHINES Filed Jan. 25, 1960 15 Sheets-Sheet 1 3- 2 $3 :1 N 5 gl P: Q 5 g to 1 N g CD a Ch 0 v 8 an v w 1- IINVENTOR. RALPH E. JOHNSON \I/VITNESS ATTORNEY Aug. 28, 1962 R. E. JOHNSON ZIGZAG SEWING MACHINES l3 Sheets-Sheet 2 Filed Jan. 25, 1960 in mm R fi INVENTOR. RALPH E. Jam/sou E? 7 ATTORNEY WITNESS 1962 R. E. JOHNSON 3,051,107

ZIGZAG SEWING MACHINES Filed Jan. 25, 1960 13 Sheets-Sheet 3 u a l4 204 IN VEN TOR.

RALPH -l5. JOHNSON W1 TNESS ATTORNEY Aug. 28, 1962 R. E. JOHNSON ZI GZAG SEWING MACHINES l3 Sheets$heet 4 Filed Jan. 25, 1960 JNVENTOR. RALPH E. JOHNSON F ig. 4.

9 ATTORNEY WIYWESS Aug. 28, 1962 R. E. JOHNSON ZIGZAG SEWING MACHINES Filed Jan. 25, 1960 13 Sheets-Sheet 5 v 'JNYENTOR.

RALPH E Jam/301v 7 ATTORNEY ZIGZAG SEWING MACHINES Filed Jan. 25, 1960 13 Sheets-Sheet 6 27o x v 7 274 275 O I 264 I Fig. 9 lo 257 V INVENTOR.

22? RALPH E. JOHNSON F lg. IO. BY

WZQ AJ; W213 TTOR/VEY Aug. 28., 1962 R. E. JOHNSON 3,051,107

ZIGZAG SEWING MACHINES Filed Jan. 25, 1960 I l3 Sheets-Sheet 7 [I ll IN V EN TOR.

RALPH E. Jam/501v BY W 51 644 ATTORZVEJ WITNESS 1952 R. E. JOHNSON 3,051,107

ZIGZAG SEWING MACHINES Filed Jan. 25, 1960 13 Sheets-Sheet 8 INVENTOR. RAL H E. JOHNSON 6 WI TNES ATTORNEZ 1962 R. E. JOHNSON 3,051,107

ZIGZAG SEWING MACHINES Filed Jan. 25, 1960 15 Sheets-Sheet 9 jfuuv ATTO Y Aug. 28, 1962 R. E. JOHNSON ZIGZAG SEWING MACHINES l3 Sheets-Sheet 10 Filed Jan. 25, 1960 R m 0 6 n m m 8 M m w w mJ m E H F P a R V. A B 7 m \w m n w 1 T 1...: nu 4 m u 0 2 0 B 7 l W 6 3 Q 3 $7M nw 2 a m m a m a 2 F ,9 m T, M @51 o m wnw w W A I4 m m m gam a mm m m WITNESS AT TORNEI l3 Sheets-Sheet 11 Filed Jan. 25, 1960 Fig. 25.

IIIIJ INVENTOR. RALPH E. Jam/son WITNESS 8" 1962 R. E. JOHNSON 3,051,107

I ZIGZAG SEWING MACHINES Filed Jan. 25, 1960 15 Sheets-Sheet 12 INVENTOR. RALPH-E. "JOHNSON BY WITNESS Aug. 28, 1962 R. E. JOHNSON ZIGZAG SEWING MACHINES Filed Jan. 25, 1960 13 Sheets-Sheet 13 JNVENTOR. RALPH E. JOHNSON United States Patent Ofitice 3,51,187 Patented Aug. 28, 1952 The present invention relates to a zigzag sewing machine and has for a primary object to provide a new and improved zigzag mechanism for a sewing machine.

More particularly, it is an object of this invention to provide an improved cam-actuated mechanism for irnparting lateral vibration to the needle bar in a zigzag sewing machine such that the sewing machine will have improved straight stitching characteristics when the zigzag amplitude is adjusted to zero. This has been accomplished in the present machine by providing a mechanism in which the needle bar driving element is positively disconnected from the actuating element when adjustment to zero is effected, and which also serves during straight stitching to remove the bias between the cam follower and the stitch pattern cam thereby eliminating unnecessary wear on the cam and providing for removal and replacement of the stitch pattern cam.

Having in mind the above and other objects that will be evident from an understanding of this disclosure, the invention comprises the devices, combinations and arrangements of parts as illustrated in the presently preferred embodiment of the invention which is hereinafter set forth in such detail as to enable those skilled in the art readily to understand the function, operation, construction, and advantages of it when read in conjunction With the accompanying drawings in which:

FIG. 1 is a front elevational view of a sewing machine embodying the present invention,

FIG. 2 is a vertical sectional view longitudinally of the sewing machine of FIG. 1,

FIG. 3 is an end elevational view of the standard end of the sewing machine of FIG. 1, with parts broken away and in section to illustrate the invention more clearly,

FIG. 4 is a vertical sectional view substantially on the line 4-4 of FIG. 2,

FIG. 5 is a detail sectional view showing the mounting of the needle bar gate,

FIG. 6 is a bottom plan view of the sewing machine of FIG. 1,

FIG. 7 is a detail sectional view substantially on the line 7-7 of FIG. 6,

FIG. 8 is a sectional view substantially n the line 8-8 of FIG. 6,

FIG. 9 is a sectional view substantially on the line 9-9 of FIG. 6,

FIG. 10 is a detail sectional view similar to FIG. 7 but on a larger scale and illustrating the feed lift cam in different positions,

FIG. 11 is a fragmentary sectional view substantially on the line 11-11 of FIG. 7,

FIG. 12 is a fragmentary top plan view of the bed of the sewing machine of FIG. 1 with the throat plate and slide plate removed,

FIG. 13 is a sectional view substantially on the line.

13-13 of FIG. 11 with the throat plate in position,

FIG. 14 is a plan view of the throat plate per se, FIG. 15 is a top plan view of the bracket arm of the sewing machine of FIG. 1, with the top cover plate removed and the face plate illustrated in section,

FIG. 16 is a detail sectional view of the top cover plate per se with the hinged plate shown in the open position, FIG. 17 is a fragmentary top plan view of the bracket arm of the sewing machine of FIG. 1 with the hinged plate open,

FIG. 18 is a vertical sectional view taken substantially on the line 18-18 of FIG. 15,

FIG. 19 is a fragmentary detail view in top plan of the cam follower mechanism of the zigzag mechanism, illustrating the mechanism in the same manner as in FIG. 15, but on an enlarged scale and in different positions of adjustment of the zigzag field,

FIG. 20 is a fragmentary detail View, partially in top plan and partially in section, of the amplitude adjustment of the zigzag mechanism,

FIG. 21 is a detail sectional view taken substantially on the line 21-21 of FIG. 20, but with the mechanism adjusted to the position of zero zigzag bight,

FIG. 22 is a detail sectional view taken substantially 'FIG. 24 is a detail sectional view taken substantially on the line 24-24 of FIG. 23,

FIG. 25 is a fragmentary top plan view of the hook mechanism with the bobbin removed and a portion of the hook broken away,

FIG. 26 is a fragmentary vertical sectional view taken substantially on the line 26-26 of FIG. 25,

FIG. 27 is a fragmentary top plan view similar to FIG. 25 but with the bobbin carrier removed and a portion of the hook broken away,

FIG. 28 is an exploded perspective View of the parts of the hook mechanism,

FIG. 29 is a fragmentary detail view on an enlarged scale of the needle guard,

FIG. 30 is a top plan view of the bobbin carrier per se,

FIG. 31 is a side elevation view of the bobbin carrier per se,

FIG. 32 is a bottom view of the bobbin carrier per se,

FIG. 33 is a detail sectional view taken substantially on the line 33-33 of FIG. 25 with the released position of the bobbin case retaining means illustrated in phantom,

FIG. 34 is a view similar to FIG. 25 and illustrating the operation of the hook with the parts shown in the loop seizing position,

FIG. 35 is a sectional view taken substantially on the line 35-35 of FIG. 34,

FIG. 36' is a view similar to FIG. 34 but with the parts shown in the loop cast-oft position,

FIG. 37 is a view similar to FIG. 34 but with the parts shown just before stitch setting position,

FIGS. 38, 39, 40 and 41 are sequential views illus trating the operation of the needle guard with the needle in the right position of the zigzag pattern, and

FIGS. 42, 43 and 44 are sequential views similar 01:

FIGS. 38-41 but with the needle in the left position of the zigzag pattern.

With reference to the drawings, there is illustrated a sewing machine having a frame including a bed 1, a standard 2 rising from one end of the bed 1, and a bracket arm 3 carried by the standard 2 and terminating in a head 4 overhanging the bed 1. The bed 1 comprises a bed plate 5, the upper surface of which constitutes the work supporting surface of the machine, and a continuous wall depending from and adjacent to the periphery of the bed plate 5 and including a front wall 6, a rear Wall 7, a standard end wall 8 and a head end wall 9. A drip plate 10 closes the bottom of the bed 1.

Arranged longitudinally of the bracket arm 3 is a main shaft 11 which at the head end is journalled in a bearing bushing 12 mounted in a transverse wall 13 between the bracket arm '3 and head 4, and at the standard end is journaled in a bearing bushing 14 mounted in a transverse wall 15 in the top of the standard 2. On the standard end of the main shaft 11 outwardly of the bushing 14 there is mounted a combined hand wheel and belt pulley 16 that is releasably clamped to the shaft by the usual clamp stop motion screw 17 and washer 18. The belt pulley 16 has a belt groove 19 that receives a driving belt 20 that is also entrained about a pulley 21 on the drive shaft 22 of a motor 23 mounted within the standard 2. The motor 23, which is of the skeleton type, has a pair of

brackets

24 and 25 secured by rivets 26 to the stator core 27, which brackets support the drive shaft 22.

The means for supporting the motor 23 Within the standard 2 forms the subject matter of the copending application of Bialy, Serial No. 4,353, filed January 25, 1960. This means comprises a vertically arranged stud 28, FIGS. 2 and 3, secured by a set screw 29 in a bore 30 in the transverse wall 15. The bracket 25 of the motor is extended at its upper end to provide an arm 31 having an aperture that slidably receives the stud 28. At its lower end, the bracket 25 is extended to provide an arm 32 having a vertically elongated aperture 33 that receives the shank of a headed bushing 34. A spacer sleeve 35 is disposed between the arm 32 and a boss 36 integral with the bed 1. A screw 37 extends through the bushing 34 and is threaded into the boss 36. The stud 28, bushing 34 and sleeve 35 are all formed of a non-conductive material such as molded nylon to insulate the motor 23 from the frame of the machine. The above mounting of the motor provides for vertical adjustment of the motor to eifect tightening of the belt 20.

In the head 4, there is mounted a needle bar 38 which at its lower end carries a needle 39 secured thereto by a needle clamp 40 which is of the type forming the subject matter of the United States patent of Koenig, No. 2,919,- 667, dated January 5, 1960. The needle bar 38 is mounted in the head 4 for endwise reciprocation and for lateral vibration. Upon endwise reciprocation of the needle bar 38, the needle 39 is thrust through the work on the upper or Work supporting surface of the bed plate 5 and, beneath the bed plate 5, it cooperates with a loop taker, indicated generally at 41, in the formation of lock stitches. The needle thus defines, the point of stitch formation on the work supporting surface of the machine. Upon lateral vibration of the needle bar 38, the needle is moved laterally of the line of feed of the work so that it will penetrate the work at different points upon successive stitches, thus defining a zigzag or ornamental stitch pattern.

For supporting the needle bar 38', there is provided a swinging needle bar gate 42 having bearing lugs 43 journaled upon a vertically arranged pivot rod 44 secured in spaced upper and

lower bosses

45 and 46 in the head 4. The gate 42 also has a pair of vertically spaced bearing lugs 47 and 48 in which the needle bar 38 is slidably mounted. The rod 44 is disposed in the lower front portion of the head 4 and in axial alignment with the loop taker mechanism as hereinafter explained. To efiect adjustment of this alignment, the rod 44 is made with a head 49 mounted in the lower boss 46, a reduced diameter intermediate portion 50 that is eccentric relatively to the head 49, and a further reduced diameter portion 51 that is co-axial relatively to the head 49 and which is mounted in the. upper boss 45. The lugs 43 of the gate 42 are. mounted on the eccentric portion 50 so that the gate 42 pivots about the axis of the eccentric portion 50. When the fastening screws of the :rod 44 are loosened, the rod 44 can be turned to effect an adjustment of the pivot axis of the gate 42, and the fastening Screws can then be tightened to lock the rod 44 in the adjusted position.. This feature of the disclosed machine forms the subject matter of the United States patent application of Goosman, Serial No. 4,493, filed January 25 1960.

'Endwise reciprocation is imparted to the needle bar 38 by a crank 52 mounted upon the end of the main shaft 11 outwardly of the bushing 12. inwardly of the bushing 12 there is mounted on the main shaft 11 a collar 53 which, together with the crank 52, prevents end play of the shaft 11. The crank 52 carries the usual crank pin 54 which is connected to one end of a needle bar driving link 55. The other end of the link 55 is formed with a hub having a bore 56 that slidably receives a. plunger 57 which is pivotally connected by a pin 58 to an arm 59 integral with a collar 60 secured by a screw 61 on the needle bar 38. Thus, upon rotation of the main shaft, endwise reciprocation is imparted to the needle bar 38. By sliding in the bore 56, the plunger 57 accommodates lateral movements of the needle bar 38 relatively to the link 55. The pivotal connection at the-pin 58 accommodates any misalignment between the needle bar 38 and the iink 55 thereby making the construction less critical and more economical to manufacture.

With reference to FIG. 23, lateral vibrations are imparted to the needle 'bar 38 by a zigzag mechanism comprising a vertically disposed cam shaft 62, the construction, assembly and alignment of which forms the subject matter of the copending United States patent application of Johnson, Serial No. 4,312, filed January 25, 1960. The cam shaft 62 is tubular or in the form of a sleeve having a central bore for receiving and thereby journaling the cam shaft upon a stud 63 mounted on a vertical axis in a boss 64 integral with the front wall of the bracket arm 3. The stud 63 has a mounting portion 65 at its lower end that is received within a bore in the boss 64 and is secured therein by a set screw 66 engaging the periphery of a reduced portion 67 of the stud 63. The upper end of the mounting portion 65 of the stud 63 has a reduced diameter annular groove 68. Above the mounting portion 65, the stud 63 is provided with an intermediate portion 69 that is larger in diameter than the mounting portion 65 and is eccentric relatively to the axis of the mounting portion 65. The upper end of the stud 63 is provided with a reduced diameter portion 70 formed on the same axis as the intermediate portion 69 and having a screw driver 71 in the upper end thereof.

The cam shaft 62 has a through bore 72 that receives the eccentric intermediate portion 69 of the stud 63 and is formed at its lower end with a gear 73 that meshes with a worm 74 on the main shaft 11 for imparting rotation to the cam shaft 62 upon rotation of the main shaft 11. For adjusting the meshing relation of the gear 73 and the worm 74, the set screw 66 is loosened and the stud 63 is turned by means of the screw driver slot 71. Because of the eccentricity of the intermediate portion 69 relatively to the mounting portion 65, as the stud 63 is turned, the cam shaft 62 and the gear 73 thereon are moved toward or away from the axis of the main shaft 11 and the worm 74 thereon. Once adjusted, the setscrew 66 is turned down to lock the stud 63 in its adjusted position.

A stitch pattern cam 75 having a peripheral cam surface is mounted on the upper end of the cam shaft 62. The cam 75 has a central aperture 77 and the upper end of the shaft 62 is enlarged diametrically to provide a flange 78 having a seat 79 formedin the top thereof for receiving the cam 75. A clamping nut 80' is rotatably mounted on the reduced upper portion 70 of the stud 63 and is threaded into the upper end of the bore 72 in the shaft 62 to clamp the cam 75 on the seat 79. To position the cam 75 on the cam shaft 62, there is provided a slot 81, FIG. 10, extending radially from the central aperture 77 of the cam, the slot 81 receiving the upper end of a positioning pin 82 that is arranged vertically in the flange 78 and secured therein by a set screw 83.

For securing the cam shaft 62 on the stud 63, there is provided an annular groove 84 in the periphery of the stud 63 adjacent to the upper end of the intermediate portion 69. The cam shaft 62 has a second flange 85 formed in the upper surface thereof with a segmental shaped seat 86, FIG. 24, that is extended through the side Wall of the shaft 62 to define an aperture 87. A segmental shaped key 88 is mounted on the seat 86 and extends through the apertnre 87. The inner edge 89 of the key 88 substantially conforms to the periphery of the groove 84 while the outer edge 90 conforms to the periphery of the flange 85. The positioning pin 82 is formed with a reduced end 91 that is adapted to be received within an aperture 92 in the key 88.

In the assembly of the above mechanism into the machine, it is first completely put together as a sub-assembly, that is, the cam shaft '62 is mounted on the stud 63, the key 88 is inserted to hold them together, the pin 82 is inserted with the end 91 in the aperture 92 to hold the key, the set screw 83 is turned down, the cam 75 is placed in position, and finally, the clamping nut 80 is turned down. All of the above is a very rough assembly in that no part of it is critical so that it can be performed very quickly and with inexpensive labor. The sub-assembly unit is then dropped into the machine with the mounting portion 65 of the stud 63 passing through the bore in the boss 64. The boss 64 is provided with tan accurately machined upper surface 93 that serves to position the unit with the gear 73 aligned vertically with the worm 74. The cam shaft 62 is pushed down until the lower end thereof abuts on the surface 93, and the stud 63 is then pushed down until the key 88 is in engagement with the upper side of the groove 83, as shown in FIG. 23. The groove 68 accommodates endwise movement of the stud 63 downwardly relatively to the surface 93, thus reducing the required manufacturing tolerances, and for the same reason, the groove 84 is elongated axially of the stud. With the unit thus inserted in the machine, the stud 63 is turned by means of the screw driver slot 71 to adjust the meshing relation of the gear 73 and the worm 74, and the set screw 66 is turned down to lock the assembly. Thereafter, the cam shaft 62 is held against endwise movement on the stud 63 by the key 88 and the surf-ace 93.

The zigzag actuating mechanism of the disclosed machine forms the subject matter of the copending United States patent application of Johnson et 'al., Serial No. 4,335, filed January 25, 1960. This mechanism comprises a vertically arranged stud 94 which, FIG. 18, is disposed in the rear of the bracket arm 3 and at its lower end, is secured by a set screw 95 in a boss 96. Pivotally mounted on the stud 94 is a bracket 97 which is a sheet metal element consisting of a vertical body portion 98 having bent therefrom at right angles at its top and

bottom ears

99 and 100, which ears are provided with aper:

tures 101 and 102 that slidably receive the stud 94. The bracket 97 is positioned vertically on the stud 94 by a sleeve 103 resting on an accurately machined surface 104 on the top of the boss 96 and having an accurately machined upper surface 105 on which the bracket 97 rests. At a point spaced from the stud 94, the

ears

99 and 100 of the bracket 97 are provided with

apertures

106 and 107 that slidably receive a pivot pin 108. The pin 108 is held against endwise movement by a locking plate 109 lying on the top of the ear 99 of the bracket 97. The plate 109 has a rearward end that is bifurcated to provide a slot 110 that slidablyreceives a reduced diameter portion of the stud 94 formed by a groove 110a. Extending inwardly from the one edge of the plate 109, FIG. 10, there is a slot 111. The pin 108 has a groove 112 defining a reduced diameter portion that is slidably received within the slot 111. A screw 113 extends through the plate 109 and is threaded into the ear 99 to lock the plate 109 and thus lock the pin 108 in position.

Pivotally mounted on the pin 108 is a U-shaped plate 114 formed of sheet metal and arranged generally transversely of the bracket arm 3, and cut away as at 115, to accommodate the main shaft 11 and the worm 74, thereby defining a base portion 116 and rearwardly extending

arms

117 and 118 disposed respectively above and below the main shaft 1 1. The upper arm 117 is bent to form an ear 119 disposed in spaced relation above the upper ear 99 of the bracket 97 and having an aperture slidably receiving the pin 108. The lower arm 118 is bent to form an ear 120 having an aperture slidably receiving the pin 6 108. The sleeve 103 is provided with a flange 121 having an accurately machined upper surface on which the ear rests for positioning the plate 114 vertically. For rigidity, the base portion 116 of the plate 114 is provided with a laterally bent stiifening rib 122.

There is provided a cam follower 123 formed of sheet metal and pivotally mounted by means of a pivot screw 124 on an ear 125 bent from the top of the plate 114. At the forward end of the follower 123 there is an upstanding follower element 126 that is adapted to cooperate With the peripheral cam surface 76 of the pattern cam 75. The rearward end of the follower 123 is bifurcated to provide a slot 127 that receives a reduced diameter portion 128 of the stud 94 to support the rear end of the cam follower against movement endwise of the stud 94 and to provide a sliding pivot for the same.

In the lower arm 118 of the plate 114 there is provided a slot 129 through which extends the one end of a pitman 130 that extends through the bracket arm 3 toward the head 4. At its other end, FIGS. 4 and 15, the pitman 130 is connected by a bolt 131 to a bracket 132 which, for adjustment, extends through a slot 133 in the bracket 132 and is threaded into the end of the pitman 130. The bracket 132 is pivotally connected to the needle bar gate 7 42 by a pin 134 extending loosely through an arm of the bracket and secured by a set screw 135 in the upper bearing lug 47 of the needle bar gate. The connection between the end of the pitman 130 and the plate 114 comprises a block 136 secured by a screw 137 on the end of the pitman and disposed on that side of the plate 114 opposite from the needle bar gate 42.

The needle bar gate 42 is biased in a counterclockwise direction about the axis of the intermediate portion 50 of the pivot rod 44 by a torsion spring 138 coiled about the portion 50 between the bearing lugs 43. The one end of the spring 138 bears against the gate 42 and the opposite end is anchored in a collar 139 secured by a set screw 140 on the rod 44. The collar 139 abuts against the top of the bottom bearing lug 43, and together with the head 49 of the rod 44, serves to prevent end play of the rod 44. The bias of the spring 138 tends to pull on the pitman 130 to the left as seen in FIG. 20. By releasing the set screw 140, the collar 139 can be turned to adjust the torsion of the spring 138 and thus adjust the bias of the zigzag mechanism. This construction forms the subject matter of the copending application of Johnson, Serial No. 4,357, filed January 25, 1960.

The bracket 97' determines the center adjustment of the ornamental stitch pattern by varying the position of the pivot pin 108 which defines the pivot axis for the plate 114. Adjustment of the bracket 97 is provided by a handle 141 secured to the locking plate 109 by rivets 142. The handle 141 extends through a slot 143 in the front wall of the bracket arm 3, and through a slot 144 in a decorative indicia plate 145 secured by screws 146 on the front wall of the bracket arm. The plate 145 is provided with the letters L, C, and R, FIG. 1, to indicate the left, center, and right settings of the center adjustment. The plate 109 is formed of spring steel and acts to bias the handle 141 upwardly to seat the same in notches 147 at the various settings. To release the handle 141 from the notches 147, it is depressed against the action of the plate 109.

The spring 138 acts to exert a pull on the pitman 130 which, through the block 136, biases the plate 114 in a clockwise direction as seen in FIG. 20 about the axis of the pivot pin 108. The plate 114, through the pivot screw 124, biases the cam follower 123 about its pivot axis defined by the stud 94 to engage the follower element 126 against the peripheral pattern surface 76 of the pattern cam 75. Upon rotation of the pattern cam 75, oscillation is imparted to the cam follower 123, the follower being moved in one direction by the pattern surface 76 and in the other direction by the spring 138. Through the pivot screw 124, oscillation of the cam fol-' lower 123 oscillates the plate 114 about the axis of the pivot pin 188. Through engagement of the plate 114 and the block 136, as the plate 114 is oscillated, the pitman 139 is pulled to the right, P16. 20, in opposition to the spring 138 and is released for movement to the eft under the action of the spring 138. Endwise movement of the pitman imparts lateral vibration to the needle bar gate 42.

The amplitude of the endwise movement imparted to the pitman 131} and thus the lateral vibration of the needle bar, depends upon the setting of the block 136 radially relatively to the pivot axis of the plate 114. To vary the amplitude, the pitm-an 131) is adapted to be moved pivotally about the axis of the pin 134 to move the opposite end thereof along the slot 129 to position the block 136 between a maximum setting and a zero setting radially of the pivot pin 1118. For this purpose, there is provided a zigzag amplitude adjustment lever 147 of the bell-crank type pivotally mounted by means of a shoulder screw 149, FIG. 23, on the lower end of the stud 63. The lever 147 consists of an intermediate portion 150 formed of spring metal and a handle portion 151 secured there to by rivets 152. The handle portion extends through a slot 153 in the front wall of the bracket arm 3 and through a slot 154 in a decorative indicia Plate 155 secured by screws 156, FIG. 1, to the front wall of the bracket arm and having numerals to indicate the setting of the zigzag amplitude. The spring portion 150 biases the handle portion 151 against the upper edge of the slot 154 to hold the lever 147 frictionally in its adjusted position. At its other end, the lever 147 carries a block 157 secured to the spring portion 150 by a rivet 158 and by a screw 159 extending through the spring portion 150 and threaded into the block 157. The head of the screw 159 is disposed in a slot 160 in the pitman 130 so that upon pivotal movement of the lever 147, the pitman 130 is pivotally moved to shift the block 136 along the slot 129.

The block 136 is formed generally cylindrical to provide a line contact on the plate 114 and it is provided with a slabbed face 161 on the side adjacent to the stud 94 to provide clearance relatively to the sleeve 103. At the zero setting of the zigzag amplitude adjustment, the end of the pitman 130 is disposed with the axis of the block 136 coaxial relatively to the pin 108. To determine this setting, the ends 162 of the slot 154 in the plate 155 are dimensioned accurately so that they will abut and serve as stops for the lever 147.

On the top of the block 136 there is provided an upstanding lug 163 having a cam face 164 that is adapted to engage the lower end of the pivot pin 108, as seen in FIGS. 21 and 22 when the zigzag amplitude is adjusted to zero for straight stitching. The cam face 164 retracts the pitman 138 against the action of the spring 138 and lifts the block 136 out of engagement with the plate 114, the plate 114 being provided with a cut-away 165 to insure clearance between the plate 114 and the block 136 when at the zero amplitude setting. Thus, at the zero setting of the zigzag amplitude adjustment, any pivotal movement of the plate 114 will not impart any movement to the pitman 130 and the needle bar gate 42 is held in a straight stitching position by the spring 138 that biases the same into a stop position determined by the engagement of the cam face 164 against the pivot pin 108. At the same time, the bias of the spring 138 is completely removed from the plate 114 and thus from the cam follower 123 so that the follower element 126 will not track the cam surface 76, thereby eliminating unnecessary wear on the cam 75 during straight stitching. A further advantage is that simply by moving the lever 151 to the straight stitching position, the bias is removed from the cam follower so that it will not interfere with changing the cam 75.

To position the mechanism accurately at the maximum zigzag amplitude setting, the pitman 130 has an accu rately machined face 166 that is adapted to abut against the periphery of the stud '63. At the maximum zigzag amplitude setting, the end of the pi-tman is positioned with the axis of the block 136 disposed co-axially with the axis of the pivot screw 124.

The zigzag amplitude adjustment provided by the lever 147 is designed to vary the lateral vibration of the needle from zero, which is for straight stitching, and a maximum, which in the present machine is approximately 0.160 inch (4 mm.). The two extreme positions at the maximum zigzag amplitude setting define the side edges of the zigzag field. The zigzag field or centering adjustment varies the straight stitching position when the amplitude adjustment is at zero, that is, the line of stitching will be placed in the center or along one of the side edges of the zigzag field. It also determines the position of the zigzag pattern within the field, that is, with the field adjustment at the center position, the lateral vibrations of the needle will be an equal distance upon each side of the center line of the field and, with the field adjustment at either the right or left positions, the lateral vibrations of the needle will be from either the right or left side edges of the zigzag field so that the one side of the pattern will be along one side edge of the field.

Upon actuation of the zigzag mechanism, the plate 114 pivots about the pin 108. Upon adjustment of the zigzag field by means of the lever 141, the plate 114 pivots about the axis of the connecting or driving screw 124 for the plate 114. To obtain the desired control of the zigzag amplitude and field, the displacement of the pin 108 by the field adjustment mechanism must be equal to the displacement of the screw 124 by the actuating mechanism. With the disclosed construction, it Will be seen that by the use of the cam follower 123 that is separate from the plate 114, the displacement of the screw 124 is less than the total throw of the cam 75. In this manner, there can be used cams which have a maximum throw that is greater than that which is designed for the particular machine, and which at the same time, will maintain the necessary condition that the displacement of the screw 124 and pin 1118 be equal. The advantage of this is that cams primarily designed for a different machine can be used, thus making the cams universal.

The assembly of the present zigzag mechanism into the machine is also very simple. After the stud 94 is inserted, the sleeve 103 and bracket 97 are placed on it. Then, with the pitman 130 and the lever 147 assembled, the plate 114 with the cam follower 123 mounted thereon, is inserted, being careful to place the end of the pitman into the slot 129 and to insert the end of the cam follower 123 into the groove 128. The pin 108 is then inserted and locked by the plate 109, the plate being inserted with the stud 94 in the slot 110 and the pin 108 in the slot 111. The screw 113 is then inserted to lock the assembly.

The top of the bracket arm 3 is open and is normally closed by a top cover plate 167 having a hinged plate 168 pivotally mounted thereon for swinging upwardly about a horizontal axis at the back of the top cover plate 167 and which overhangs the cam 76 and stud 94. The pivotal mounting for the hinge plate 168 comprises lateral lugs 169 on the hinged plate 168 that are seated in the ends of leaf springs 170 secured to the underside of the plate 167. The springs 170 bias the lugs against the underside of the top cover plate 167 which at the point of contact are formed with V-shaped recesses to establish an overcenter condition for holding the hinged plate in its open and closed position. The top cover plate 167 is formed with a cut-out 171 to provide for removal of the cam 75 from the cam shaft 62 when the hinged cover 168 is open.

The top cover plate 167 is secured to the top of the bracket arm 3 by two screws 172 extending through apertures in the top cover plate and threaded into holes 173 in the top of the bracket arm 3. The screws 172 are 10- 75 cated beneath the hinged plate 168 so that, for appearance,

they are covered when the hinged cover 168 is closed. The cover plate 167 is also formed with a bore 174 that is accurately dimensioned and located to receive the free end 175 of the stud 94. To position the cover plate initially at assembly, there is formed therein at the end adjacent to the head 4 a pair of spaced depending lugs 176, FIGS. 2 and 15, that define a groove therebetween for receiving the head of a screw 177 carried by a horizontal wall 178 integral with the frame of the machine and thereby locating the cover plate laterally of the bracket arm 3 while permitting movement thereof endwise of the bracket arm relatively to the stud 94 and removal of the cover plate from the bracket arm. The screw 177 and the end 175 of the stud 94 accurately locate the cover plate 167 on the bracket arm 3 and the holes for the fastening screws -172 are made sufi'iciently loose to accommodate manufacturing errors. When the screws 172 are tightened, they then secure the cover plate 167 and it in turn serves to support the end 175 of the stud 94. The screws 172 are located closely adjacent to the stud 94 and are spaced both endwise and transversely of the bracket arm 3 to fasten the cover plate securely and to provide maximum support for the stud 94. In this manner, the stud 94 is supported by means which do not interfere with assembly of the elements of the zigzag mechanism on the stud 94.

This feature of the disclosed machine forms the subject matter of the copending application of Johnson, Serial No. 4,334, filed January 25, 1960.

The hinged plate 168 carries a pair of thread spool pins 179. The thread from a thread spool on the pins 179 is run through a guide 180 on the cover plate 167, to a needle thread tension device 131 of the type forming the subject matter of the United States application of Johnson, Serial No. 692,323, filed October 25, 1957, now Patent No. 2,955,775. From the tension device 181, the thread extends to a take-up mechanism which is of the conventional link type including a lever 182, FIG. 4, having a thread eye 183 at one end extending through a slot 184 in the frame, FIG. 1, and pivoted at its other end to an offset portion 185 of the crank pin 54, and at an intermediate point, being pivotally connected to an anchor link 186. From the take-up mechanism, the thread runs through the thread guide of the needle clamp 40 to the eye of the needle 39.

There is provided a sewing light 187 that is arranged transversely of the frame of the machine of the inside of the junction of the bracket arm 3 and head 4. As seen in FIG. 2, the light 137 is seated in a concave recess 188 having a rear wall 189 integral with the frame of the machine and having the front closed by a domeshaped bulge 190 integral with a plate 191, FIG. 1, secured to the bracket arm 3 of the machine by a screw 192. The light 187 is carried by a socket 194 secured by a screw 195 to the rear wall 189.

The light 187 is supplied with power through a lead 196 which, together with the leads 197 for the motor 23, FIGS. 2 and 3, are connected to a molded plastic terminal 198 mounted in a recess 199 in the end wall of the standard adjacent to the bed. Power is delivered to the terminal 198 by leads 2% extending .a self-anchoring rubber connector 291 that is anchored in a cut'out 292 in the wall 2% of the recess 199. A device such as a foot controller (not shown) for controlling the speed of the motor 23 is adapted to be connected to the terminal 198 by leads 294 extending through a second self-anchoring rubber connector 205 anchored in a cut-out 2136 in a wall 207 of the recess 199. The recess 199 is closed by a plastic cover 268 secured by screws 209 threaded into holes 216 in the

walls

203 and 207. A plate 211, FIG. 2, secured by screws (not shown) threaded in holes 212, FIG. 3, in the standard 2 closes the end wall of the standard and provides for access to the motor 23, belt 20, and other elements in the standard' The power lead 239 is held by a bracket 213 that bends it along the rear wall of the standard 2 to control the lead and thus facilitate dropping the machine in a cabinet. The controller lead 204- is lead downwardly through a slot 214 in the front wall 6 of the bed 1 and is held therein by a two-part plastic fastening element 215. The slot 214, together with a similar slot 216, are designed to provide for treadle drive of the machine, the slots being formed along lines defined by the run of a belt about the belt groove 19 in the hand wheel 16 and about the pulley of a conventional treadle mechanism (not shown).

The bobbin winder of the machine comprises a spindle 217 for receiving a bobbin, the spindle being journaled in the end of a lever 213 frictionally pivoted to the frame and adapted to be moved to engage a driving wheel 219 on the spindle against the periphery of the hand wheel 16.

On the bed plate 5 of the machine in front of the standard there is provided a spool pin 220 for a thread spool that is used during bobbin winding and a tension device 221.

Mounted vertically in the standard 2 is a shaft 222, FIG. 2, journaled in upper and lower bearing lugs 223 and 224 respectively. The shaft 222 carries a bevel gear 225 mounted on the upper end thereof above the bearing lug 223 and meshing with a similar gear 226 on the main shaft 11. On the lower end of the shaft 222 below the lever bearing lug 224 there is mounted a crank 227. The upper end of the shaft 222 is extended through the hub of the gear 225 and abuts against the main shaft 11, the end, of the shaft 222 being crowned to provide substantially a point contact. This contact, together with the hub of the gear 225 which abuts against the upper surface of the upper bearing lug 223 prevents end-play of the shaft 222. The crank 227 is spaced from the bottom of the lower bearing lug 224 to permit relative motion between the standard 2 and shaft 222 caused by the difference in the temperature induced expansion between them, the frame of the machine being die-cast aluminum while the shaft 222 is of steel.

About the point of penetration by the needle 39, the bed plate 5 is provided with an opening that is normally closed by a throat plate 228, FIG. 4, and a slide plate 229, the upper surfaces of which, together with the upper surface of the bed plate 5, constitute the work supporting surface of the machine.

For releasably securing the throat plate 228 in position, there is formed a seat 23%, FIGS. 12 and 13, about the opening in the bed plate 5 on which it is seated. A pin 231 and a plunger 232 are arranged transversely on opposite sides of the seat 230. The pin 231 is press or taper fitted into a boss 233 integral with the bed plate 5 and having an upper surface forming a part of the seat 230 so that the head of the pin 231 in effect is upstand ing from the seat 231 The throat plate 223 is provided with an aperture 234 that slidingly receives the head of the pin 231.

The plunger 232 extends through and is mounted for endwise sliding in a bore 235 in a boss 236 integral with the bed plate 5 and having an upper surface forming a part of the seat 230. The plunger 232 has a head 237 at its upper end that overlies the seat 230 and has a compression spring 238 coiled about the same for biasing the plunger 232 downwardly.

The throat plate 228 has a slot 239 extending inwardly from the edge thereof and terminating in a seat 240 that receives the head 237 of the plunger 17. The seat 240 has a bottom surface opposed to the underside of the head 237, which surface is planar and is inclined relatively to the plane normal to the axis of the plunger 232, with the minimum depth from the top of the throat plate 228 at a point 241. The underside of the head 237 is planar and is normal to the axis of the plunger 232 so that the opposed surfaces of the head 237 and the seat 240 will engage only at the minimum depth point 241. JIhus, the action of the spring 238 is applied more closely to the center of the 1 l. throat plate 228, and acts to pivot the same about the point of engagement of the throat plate 228 at the open end of the slot 239 on the seat 230.

The throat plate 228 is easily removed by lifting the side thereof off the pin 231 and sliding it from beneath the head 23-7 of the plunger 232. It is replaced equally as easy by inserting it under the head 237 with the plunger 232 passing into the slot 239 until the head 237 snaps into the seat 240.

The above throat plate fastening means forms the subject matter of the copending United States patent application of Johnson, Serial No. 4,280, filed January 25, 1960.

The throat plate 228 is provided with a needle aperture 242 through which the needle 39 passes. The needle 39 defines the point of stitch formation on the work supporting surface of the machine. The work is advanced across the work supporting surface of the machine past the point of stitch formation by a four motion feeding mechanism comprising a feed bar 243 carrying a feed dog 244 operating through feed dog slots in the throat plate 228 to enage the work. The work is held down against the feed dog 244 and throat plate 228 by a presser foot 235 carried on the lower end of a presser bar 246 mounted in the head 4 for endwise sliding and biased downwardly by a spring 247, FIG. 4. Journaled longitudinally of the bed at the front of the machine is a feed advance shaft 248 having rock arms 249 which are pivotally connected to one end of the feed bar 243. Oscillation is imparted to the feed advance shaft 248 by an eccentric 250 on the main shaft 11 which is embraced by a fork on the upper end of a pitman 251. Intermediate its ends the the pitman 251 has a laterally extending pin 252 extending into a groove 253 in a block 254 that is pivotally mounted in the transverse wall 15 of the frame by means of a stud 25 and which includes a handle 256 extending to a position accessible to the operator. At its lower end, the pitrnan 251 is connected to a crank arm 257 on the feed advance shaft 248.

The feed lift mechanism comprises a feed lift shaft 258 journaled in the rear of the bed 1 by cone-shaped end bearings 259 in the boss 36 and a boss 261. The one end of the feed lift shaft 258 has a crank arm 262 which at its free end is connected by a link 263 to the feed bar 243 for imparting feed lift motions to the feed bar 243 upon oscillation of the feed lift shaft 258. At the other end of the feed lift shaft 258 there is a second crank arm 264 having a hub 265 at its free end that receives a cylindrical pin 266 mounted therein for turning adjustment, which turning is facilitated by a screw slot 267 in the end thereof. The pin 266 is secured in its adjusted position by a set screw 50. Integral with the pin 266 is a stud 269 that is eccentric relatively to the axis of the pin 266. A cam follower element 270 is pivotally mounted on the stud 269 and is held thereon by a screw 271. The crank arm 264 is disposed to locate the cam follower element 270 in engagement with an axial displacement cam surface 272 formed on the upper surface of the crank 227. A coil compression spring 55 is disposed between the crank arm 262 and the underside of the bed plate 5 to bias the feed lift mechanism in the direction to lower the feed bar 243 and to hold the cam follower element 276 in tracking engagement with the cam surface 272. Thus, upon rotation of the crank 227, oscillation is imparted to the feed lift shaft 258.

The ci'ank arm 262 is located adjacent to the boss 261 and is offset to position the link 263 in a plane normal to the boss 261, and the crank arm 264 is located adjacent to the boss 36 and is also offset to position the cam follower element 276 close to a plane normal to the boss 36. In this manner substantially only torsional forces are applied to the shaft 258 with a minimum of bending. The spring 273 also serves to pre-stress the feed lift shaft 253 and thus minimizes torsional deflection of the shaft.

The feed path, which is the path of motion of a selected point on the feed dog 244, is a function of the motion imparted to the feed dog by the feed advance shaft 1.2 248 and the feed lift shaft 258. The desired feed path and the timing of the feed motion are determined by basic considerations, for example, experience has shown that a particular rise of the feed dog above the throat plate produces an optimum engagement of the feed dog against the work, a relatively flat mot-ion of the feed dog during feeding is desirable, the feed must be operative while the needle is out of the work and preferably as late as possible in the cycle, and the stitch length should be adjustable from zero to a predetermined maximum. There are also various mechanical considerations,

for example, the feed dog overlies the hook and must be designed so that there is always adequate clearance between the two but which, at the same time, locates the hook as close as possible to the throat plate to provide a minimum needle bar stroke.

The mechanics of the system are designed to produce a desired feed motion, which always represents some compromise that is determined by trial and error to be best suited to the particular sewing machine. Once established, the system cannot be freely changed since any changes in relative timing between the feed lift motion and feed advance motion, and any changes in the amplitude of the motions will produce changes in the feed path, thus destroying the designed optimum.

In the present machine, the timing of the feed advance is obtained by the angular position of the eccentric 250 on the main shaft 11. Since the angular position of the crank 227 on the shaft 222 is fixed by the hook requirements, the timing of the feed lift is obtained by the configuration of the cam surface 272 on the crank 227.

Having determined the feed lift motion necessary to obtain the desired feed path, it then becomes necessary to obtain the desired rise of the feed dog 244 above the throat plate 228. This, of course, can be obtained, by design and by maintaining strict manufacturing tolerances. However, this is relatively expensive. To reduce manufacturing costs, it would be preferable to provide a construction in which the manufacture of the element is less critical and which is adjustable to obtain the desired alignment of the parts. In the present machine, this adjustment has been provided by the eccentric stud 269. By rotating the pin 266, the feed lift is adjusted to provide the desired rise of feed dog 244 above the throat plate 228.

Such an adjustment in the feed must be made without altering the mechanics of the system such as to vary the feed path significantly. In the operation of the present machine, the displacement of the cam follower element 270 by the cam surface 272 produces a certain angular movement of the crank arm 264, the feed lift shaft 258 and the crank arm 262, thus producing a certain feed lift motion. The angular movement of the crank arm 264 for any given displacement of the cam follower element 270 is dependent upon the location of the cam follower 270 radially relatively to the pivot axis of the crank arm 264, which is the axis of the feed lift shaft 258. Shortening the radius will produce an increased angular movement of the crank arm 264 while lengthening the radius will produce a reduced angular movement of the crank arm 264. Upon turning the pin 266 to adjust the rise of the feed dog, the eccentric stud 269 moves in an are about the axis of the pin 266, thus having a first component in a direction tangential to the arc of motion of the pin 266 about the axis of the feed lift shaft 258, which direction is substantially vertical, and which component adjusts the feed lift motion to obtain the desired rise of the feed dog above the throat plate. However, the pin 266 also has a second component of motion that is in a plane that is substantially horizontal and is defined by the axis of the feed lift shaft 258 and the pin 266. In effect this second component varies the lever arm between the axis of the feed lift shaft 258 and the point at which the force is applied by the cam follower element 270 to the crank arm 264, i.e., the axis of the stud 269. Such a variation, changes the feed path.

To minimize the effect upon the effective length of the crank arm 264 by the eccentricity of the stud 269, there is provided a stop shoulder 274 on the crank arm 264 that is designed to be engaged by the edge 275 of the cam follower element 270 when the stud 269 is adjusted to its maximum and minimum positions in the direction tangential to the arc of motion of the pin 266 about the axis of the feed lift shaft 258. Thus, the pin 266 is limited approximately to one half of one revolution, and while obtaining the desired adjustment in the rise of the feed dog, it eliminates one half of the undesired variation in the effective length of the crank arm 264, i.e., one half of the component in the plane defined by the axes of the feed lift shaft 258 and pin 266. At the same time, by designing the mechanism such that the desired setting of the eccentric is at the midpoint of its arc of adjustment, and by making the eccentricity of the stud 269 more than the normally required adjustment, a minimum of the undesired displacement of the stud 269 is obtained.

The axis of rotation of the crank 227, which is the axis of the shaft 222, is normal to a horizontal plane containing the axis of the feed lift shaft 258, and the axis of the pin 266 is parallel to the axis of the feed lift shaft 258 and intersects the axis of the shaft 222. The cam surface 272 on the crank 227 is planar and inclined to effect a displacement of the cam follower element 270 axially of the shaft 222. The cam follower element 270 has a cam engaging surface 276 which is arcuate in a direction radially of said cam surface 272 and is defined by straight parallel lines in a direction perpendicular to the radius of said cam surface. The cam follower element 270 is free to pivot about the axis of the stud 269 and because of the arcuate configuration of the cam engaging surface 276 and the planar configuration of the cam surface 272 there is line contact between the cam engaging surface 276 and the cam surface 272 which, as the cam surface 272 is rotated and presents a differently inclined surface to the surface 276 between the lines A and B, FIG. 10. In this manner there is provided a substantial bearing between the

surfaces

272 and 276 which can accommodate the variations in the inclination of the cam surface 272 as it rotates, and also relieves wear on the cam engaging surface 276 by continuously shifting the line of engagement to distribute the wear over a large area. At the same time, by virtue of the fact that the line of contact is a straight line perpendicular to the radius of the cam surface 272, the points of contact along the line are spaced different distances from the axis of the crank 227, e.g., as seen in FIG. 11, the ends of line of contact A engage the surface 272 along a circle C While the mid-point engages along a circle E while the mid-point engages along a circle F. Thus there is defined an annular engaging surface on the cam surface 272 extending between the circles C and F, which again reduces wear by distributing it over a large area.

"The above feeding mechanism forms the subject matter of the copending United States patent of Johnson, Serial No. 4,429, filed January 25, 1960.

The hook 41 forms the subject matter of the copending United States Patent applications of Johnson, Serial No. 4,387, filed Jan. 25, 1960, and Serial No. 4,379, filed January 25, 1960.

The hook 41 has an integral depending hook shaft .277, FIG. 26, journaled in a wall 278, FIGS. 2, 4 and 6, integral with the bed 1 and the

bosses

233 and 236. At its lower end, beneath the wall 278, the hook shaft 277 has a crank arm 279 connected by a link 280 to one ann 281 of a bell crank lever pivotally mounted intermediate its ends in the wall 278 by a pivot screw 282 and having a second arm 283 which is connected by a pitman 284 to the crank 227 (FIG. 6). Thus, oscillation is imparted to the hook 41 upon rotation of the crank 227. The mechanics are such that one cycle of oscilla- 14 tion is imparted to the hook 41 upon each rotation of the main shaft 11.

The hook 41 which is illustrated in detail in FIGS. 25 through 33 is generally cup-shaped and comprises a ring 285 that is arcuate in cross section and carried by an arm extending from the cover edge of the ring and radially relatively to the hook shaft 277. The arm 286 in effect defines the bottom of the ring 285 which is open except for the arm 286. The ring 285 is also open at the top and has an inwardly directed flange 287 that terminates in a free edge 288 which is circular and is disposed concentrically of the axis of the hook shaft 277. The flange 287 is continuous except for a gap formed by a slot 289 cut through the flange 287 from the free edge 288 into the ring 285, the slot 289 being inclined relatively to a radius from the axis of the hook shaft 277 to define a loop seizing beak 290 internally of the hook 41.

The needle 39 descends inside and closely adjacent to the flange 287 and is thus disposed adjacent to the path of travel of the loop seizing beak 290. This mechanism is designed so that as the needle 39 rises, it will throw a loop of thread into the path of travel of the loop seizing beak. The width of the slot 289 and the inclination of it relatively to the axis of the hook is designed to produce -a gap in the ring that, at its opening in the flange, is Wide enough angularly of the ring 285 to accommodate the needle thread loop, or in other words, the width of the gap is determined by the clearance required to permit loop formation. To accommodate movement of the needle 39 laterally of the line of feed during ornamental stitching, the pivot axis of the needle bar gate 42, which is defined by the pivot rod 44, is aligned with the axis of the hook shaft 277 so that upon lateral movement of the needle 39, its deposition radially of the hook 41 will not change and it will also be in operative relation relatively to the path of travel of the loop seizing beak 298. At the same time, the hook 41 is located in front of the needle 39 and feed dog 244 so that it is readily accessible by means of the slide plate 229 for the purpose of changing the bobbin.

A thread carrier, or specifically, -a bobbin carrier 291, FIGS. 25 and 30-32, is mounted internally of the hook 41 in a manner to provide for oscillation of the ring 285 relatively thereto and for passage of the needle thread loop around the same. The bobbin carrier is formed with an annular wall 292 that defines a recess or well for receiving a thread carrying bo bbin 293, FIG. 34, the wall 292 having an inwardly directed flange 294 at its lower end upon which the bobbin 293 rests. To facilitate removal of the bobbin, there is provided a finger notch 295. Extending from approximately the mid-point endwise or vertically of the wall 292 and substantially normal thereto is an outwardly directed flange 296. To support the bobbin carrier 291 in the ring 285, there is provided cooperating bearing surfaces between them. With reference to FIGS. 30-3 2, there is a peripheral groove 297 formed in the flange 296 and designed to receive the flange 287 of the ring 285, the flange 287 constituting a bearing rib for supporting the bobbin carrier 291. The groove 297 is defined by an upper bearing surface 298 that bears against the upper surface of the flange 287, a lower hearing surface 299 that bears against the lower surface of the flange 287, and a peripheral bearing surface 300 that is formed on a radius complemental to the radius of the free edge 288 of the flange 287 and is in bearing engagement with the free edge 288.

Above the upper bearing surface 298, the flange 296 has an arcuate free edge 301 that is generally concentric with the ring 285 and terminates over the flange 287 at a point spaced from the free edge 288 thereof. The

needle thread loop slides along the edge 301 as it is expanded and thrown about the bobbin carrier by the loop seizing beak 290. Beneath the lower bearing surface 299, the flange 296 has a free edge 302 that is also concentric with the ring 285 and for clearance is spaced