US2753823A

US2753823A - Seam-openers

Info

Publication number: US2753823A
Application number: US467933A
Authority: US
Inventors: David N Judelson
Original assignee: OSCAR I JUDELSOHN Inc
Current assignee: OSCAR I JUDELSOHN Inc
Priority date: 1954-11-10
Filing date: 1954-11-10
Publication date: 1956-07-10
Anticipated expiration: 1973-07-10

Description

y 10, 1956 D. N. JUDELSON 2,753,823

SEAMOPENERS Filed NOV. 10, 1954 4 Sheets-Sheet 1 IN VEN TOR. 04 W0 4 JUDELSQ/V y 0, 1956 D. N. JUDELSON 2,753,823

SEAM-OPENERS Filed Nov. 10, 1954 4 Sheets-Sheet 2 FIG. 2. FIG. 5.

' INVENTOR.

04 W0 M duoszsolv July 10, 1956 D. N. JUDELSON SEAM-OPENERS 4 Sheets-Sheet 3 Filed Nov. 10, 1954 FIGS.

FIG. IO.

INVEN TOR. DAV/D IV. JUDELSOA BY Mn M ATTORNEY July 10, 1956 D. N. JUDELSON SEAM-OPEJNERS Filed Nov. 10, 1954 4 Sheets-Sheet 4 .P FIG. u.

FIG. 13.

IN VEN TOR.

D4 V/D M Jupa s 04 United States Patent SEAM-OPENERS Application November 10, 1954, Serial No. 467,933

32 Claims. (Cl. 112217) The present invention relates to sewing mechanisms for forming a folded length of fabric into a continuous tube, and in particular to combined stitching, folding, pressing and wind-up mechanisms for joining two superposed layers of a folded fabric along one side edge by line of stitching to form a continuous tube, for pressing open the stitched seam and for winding up the formed tube with the seam thereof in open and flat condition.

Various folding mechanisms have been suggested for use in conjunction with a sewing machine for separating the margins of a folded length of fabric along and outwardly of a marginal stitched seam, and for turning such margins back upon the superposed upper and lower layers of the fabric adjacent to and overlying the line of stitching. Typical apparatus includes conventional sewing mechanisms having a presser foot, a needle, and a feed dog arranged in cooperating relation to form the line of stitching. Following or trailing the sewing mechanisms is a specially-formed turning block, which in association with a flat blade acts to separate the margins and turn the margins back in directions opposite to each other and toward the respective underlying layers of the body portions of the tube. After folding, appropriate means such as cooperating rollers, are employed to pinch the open seam and produce sharp creases at the folds and to permanently set the seam in open condition. A typical construction of this type may be found in U. S. Patent No. 1,549,484 of August 11, 1925 and issued in the name of P. Gardner.

Such apparatus has presented numerous practical difficulties, both from the standpoints of reliability in opening the seam and actual utilization.

One of the primary requirements for the seamed tube, which is ultimately bias-cut in the manufacture of binding tapes and the like, is that the seam to be opened continuously throughout its length and to a maximum depth; that is, both margins outwardly of the seam should be completely folded back onto the adjacent and underlying superposed layers of the body portions of the tube, such that the tube will not have gathers or bulges along the seam or margins open in a random fashion. Meeting this requirement is rendered still more complex in view of the relatively small width of the margins which are to be folded back; the margins usually are of the order of to M; of an inch such that the final bias-cut goods will have a minimum of double thickness material disposed symmetrically of the stitched seam. Still further, the apparatus must be employed with cloths of varying qualities and thicknesses running the gamut from relatively thick material, such as corduroy to thin and easily distorted material, such as nylon.

In the utilization of combined stitching and seam-opening apparatus, the operator manually feeds the superposed layers of material to the sewing mechanisms such that a line of stitching is formed along the edges of the superposed layers remote from the fold. In the feed of such material, the operator visually observes the position of the edges in relation to the needle such that a ice minimum width of margin is left outwardly of the stitch line for opening. Further to this end, it is conventional to employ a vertical oscillatory knife adjacent the needle which shears away edge-adjacent portions of the margins such that the margins are trimmed to equal widths. Not only is the operator concerned with proper lateral feed of the folded materials in relation to the needle, but further with maintaining tandem feed between the superposed layers of the material. As-is well understood, with a conventional sewing machine employing a bottom feed dog, there is a tendency for the lower layer of material to be advanced past the needle more rapidly than the upper layer or run in that there is creep between the respective layers due to the action of the feed dog on the lower layer. To avoid such creep, the operator normally holds back on the lower run or layer in accordance with judgment and based upon experience. With a fairly skilled operator, it is possible for the superposed layers to be fed in unison such that at the end of a relatively short tube length, the trailing edges of the layers substantially coincide. However, even the most skilled operators experience difficulty in maintaining registry between the layers in running through longer lengths of goods; it is not infrequent that the creep of the lower layer relative to the upper layer causes distortion along the length of the tube, and/or improper matching at the end of the tube length. Ultimately such distortion will cause a loss of material and effect the bias of the materials which are cut from the tube.

It is an object of the present invention to provide improved tube-stitching and seam-opening mechanisms which obviate one or more of the aforesaid difliculties. Specifically, it is within the contemplation of the present invention to provide mechanisms for reliably and continuously opening a seam in a length of tubular goods and for ultimately forming such tubes with speed, simplicity, and the assurance that distortions will not be introduced into the seam tube throughout its length.

In accordance with an illustrative embodiment demonstrating features of the present invention, in combination with conventional sewing apparatus, there are provided mechanisms for spreading or separating the margins of a tube of goods outwardly of a seam and for partially turning back the margins, and further mechanisms for completely turning back the margins in directions opposite to each other and into abutment with the respective layers of the tube body. The latter mechanisms -are effective to permanently set the margins in their turned back or open condition.

As a feature of the invention, the stitching or sewing zone is effectively isolated from the operator by a pretensioning system which along with pulling or windup mechanisms uniformly tensions the tube of goods across its width. By maintaining uniform tension on the goods, the possibility of the lower layer or run of the goods being displaced relative to the upper layer due to the action of the presser foot is minimized, and the random hold-back effects of the operator are effectively isolated from the stitching zone. Thus, even though the operator guides the goods in relation to the stitching mechanisms, and the feed dog is effective during the stitching operation, the upper and lower layers of the goods are fed in relatively fixed relation to each other. Still further, the pretensioning and pulling mechanisms provide an eifective means for orienting the folded goods in relation to the stitching and selvage-trimming mechanisms, such that once the folded goods is started in a proper direction and position relative to the stitching needle, reasonable uniformity is insured in the width of the tube and the maximum width of the goods may be utilized with attendant savings in cost. It is extremely advantageous to have a uniform width tube for the subsequent bias-cutting opera- 3 tions, as can be appreciated upon reading co-pending application Serial No. 446,374 filed July 28, 1954.

As a still further feature of the invention, the seamclosing and pressing mechanisms are adjustable in relation to and follow thickness variations of the goods. Thus, even though the thickness of the goods being processed may vary from run to run, the same mechanisms may be effective to completely and continuously open the margins and to press the same into abutting relation with the body portion of the tube.

The above objects, brief description and further features of the present invention will be best appreciated by reference to the following detailed description of an illustrative embodiment, when taken in conjunction with the accompanying rawings, wherein:

Fig. 1 is a plan view with parts broken away and shown in section of a combined tube-forming, seam-opening and wind-up machine embodying features of the present invention;

Fig. 2 is an enlarged plan view showing the details of the seam-forming and opening mechanisms, with a tube of goods in operative relation as when being fed continuously through the machine;

Fig. 3 is a view similar to Fig. 2 but with the tube of goods removed and parts of the machine broken away and shown in section for clarity;

Fig. 4 is a sectional view, on an enlarged scale, showing the details of the sewing and selvage-trimming mechanisms incorporated in a machine constructed according to the present invention;

Fig. 5 is an elevational view showing the details of the seam-opening and margin-turning and pressing assembly when viewed from the left of Figs. 2 and 3;

Fig. 6 is an enlarged perspective view of a part of the assembly shown in Fig. 5;

Fig. 7 is a sectional View on an enlarged scale taken substantially along line 77 of Fig. 3 and looking in the direction of the arrows;

Fig. 8 is a sectional view taken substantially along the line S-S of Fig. 3 and looking in the direction of the arrows;

Fig. 8a is a sectional view taken substantially along the line 8a8a of Fig. 3 and looking in the direction of the arrows;

Fig. 9 is a sectional view on an enlarged scale taken substantially along the line 9-3 of Fig. 3 and looking in the direction of the arrows;

Fig. 10 is a sectional view on an enlarged scale taken substantially along the line Til-1&9 of Fig. 3 and looking in the direction of the arrows;

Fig. 11 is an elevational view, with parts broken away, showing the details of the wind-up mechanisms, as viewed from the right of Fig. 1;

Fig. 12 is a sectional view of the wind-up mechanisms taken substantially along the line 1 ll of Fig. l and looking in the direction of the arrows;

Fig. 13 is a sectional view showing a portion of the wind-up mechanisms of Fig. 12, and illustrating the beginning of wind-up of a seamed tube of goods;

Fig. 14 is an elevational view of the wind-up rollers showing the portions thereof which are in substantial alignment with the sewing mechanisms; and

Fig. 15 is a sectional view taken substantially along the line 1515 of Fig. 1 and looking in the direction of the arrows.

Referring now specifically to the drawings, there is shown in Fig. 1 a machine 10 demonstrating principles and features of the present invention which is arranged to form and open a seam s in one side of a piece of material M which includes superposed layers or runs m1, m2 folded centrally about a fold line f. The machine includes a seam-forming and opening station 12, a pretensioning and feeding system 14 in advance of the seamforming and opening station 12, and wind-up and pulling mechanisms 16 trailing the station 12.

As seen best in Figs. 3 and 4, the sewing mechanisms at the station 12 are conventional and include a feed dog 20 movable through a feed slot or throat 22 in a feed bed 24, a vertically reciprocable needle 26 supported on a needle bar 23, and a presser foot 30 supported on a presser foot bar 32. Secured to and operable with the needle bar 28 is a knife bar 34 which supports a trimmer 36 in the form of a vertically oscillating blade having a shearing edge which is adapted to coact with a fixed blade 38 secured within a well 40 on the feed bed 24. The coaction of the feed dog 29, the needle 26, the presser foot 3% and the fixed and

movable knives

36, 38 is such that the upper and lower layers m1, m2 of the material M are stitched along the side remote from the fold line f and the marginal portions n, p2 are trimmed along lines substantially parallel to the stitched line s. The thus formed marginal portions pr, )2 ultimately are folded over upon the adjacent layers m1, m2 of the tubular body.

In order to guide the material M in the linear stitch path in relation to the needle 26, a guide wire 42 is arranged along the path extending past the needle 26, the guide wire being anchored at its leading end in a bracket 44 having an elevated horizontally-extending tongue 44!: and at its trailing end in the seam-opening mechanisms, which will be subsequently described.

The pretensioning and feeding system 14 in advance of the stitching station 12 effectively isolates the operator from. the sewing mechanisms. Additionally, the system facilitates lateral adjustment of the edges along which the seam is formed in relation to the sewing mechanisms, and conjointly with the take-up or wind-up mechanisms 16, maintains uniform tension in the width and length of the material M during passage through the sewing and seamopening station 12. As seen best in Figs. 1 and 15, the pretensioning and feeding system 14 includes a set of tensioning bars 46, 48, 50 and 52. The outer tensioning bars 46, 52 carry at their end remote from the sewing mechanisms longitudinally extending fold-forming

members

54, 56 which are in end-to-end alignment with each other. The fold-forming member 54 is in the form of a rigid bar extending at right angles to the tensioning bar 46 and about which the material is wrapped preliminary to passage through the tensioning bars 46, 48, 5t), 52. The fold-forming member 56 is in the form of a thin wire fabricated of an appropriate springy material such as to exert a lateral biasing effect on the goods or material M during the passage through the station 32, and particularly during traverse past the needle 26. The tensioning bars 46, 52 extend slidably through appropriate bearings 58 in the supporting brackets and are connected together by a cross-bar 69 for lateral adjustment. A set screw 62 is tapped intothe bearing and engageable against the tensioning bar 46 to fix the tensioning bars 46, 52 in various positions of lateral adjustment with the aligned fold-forming

members

54, 56 in various positions of adjustment relative to the guide wire 42.

As seen best in Fig. 15, the tensioning bars 46, 48, 5t) and 52 are arranged to define a sinuous feed path for the material M in advance of the station 12. Specifically, the tensioning bars 48, 50 are arranged with their centers along a reference plane R, the tensioning bar 46 is arranged with its lower peripheral surface in tangential relation to the reference plane R, and the tensioning bar 52 is arranged with its upper peripheral surface in tangential relation to reference plane R. Threading of the goods M through the tensioning bars is such that the upper and lower runs pass on opposite sides. of the tensioning bar 46, over the tensioning bar 48, beneath the tensioning bar 50 and on opposite sides of the tensioning bar 52. Thus, between the point of peripheral contacts with the tensioning bars '48, 50 the runsor layers m1, m2 have a large area contact with each other, which area Contact substantially isolates any pulls exerted on the 133 6181711, mg in advance of 'the te'n'sioning bar 46. With respect to the reference plane R the sinuous feed path includes-first and second runs or traverses of similar curvature which are oppositely directed.

At the station 12 and trailing the sewing mechanisms, are seam-opening mechanisms 64 arranged to spread the margins p1, p2 of the tube, to partially turn the margins, to finally turn the margins, and to press the margins into abutting relation with the layers m1, m2 of the tube of goods. The mechanism 64, as seen best in Figs. 5 to 10, includes a wedging or spreading section 66 for opening the seam or spreading apart the marginal portions pr, 12, a seam-opening or turning section 68 for partially turning the marginal portions p1, p2, and a margin-turning and pressing section 70 for completing the turning of the marginal portions and permanently pressing the same into contacting relation with the body of the tube. For the sake of convenience in construction, and as shown best in Fig. 6, the mechanisms 64 include a one-piece turning block which in the first or seam-spreading section 66 is of progressively increasing cross-section from a leading edge 72 toward the entry end of a channel or guideway 74 formed longitudinally of the seam-turning section 68. The seam-spreading section 66 includes an upstanding or vertical camming face 73 which is formed with a longitudinal slot 75 into which the guide wire 42 extends and is anchored. In that the guide Wire 42 is of exceptionally small cross-section, it will be appreciated that the camming surface 73 lies substantially in a common plane with the guide wire 42.

The guide or channelway 74 is of uniform V-shaped crosssection throughout its length and includes converging camming surfaces 74a, 74b which meet along an apical contact line 740, which line is in substantial axial alignment with the guide wire 42 and in coplanar relation with the camming surface 73.

The one-piece turning block is further formed with a presser member 76 having a planar contact surface 76a in the region of the seam-turning and pressing section 70 which contact surface 76a is spaced below the plane of the apical line or throat 740 of the channel 74 for a purpose which will be apparent hereinafter.

The margin-turning and pressing section 70 further includes a movable presser member 78 having a contact or pressing surface 78:: which is coextensive with and abuts the planar contact surface 76a. The movable presser member or plate 78 is adjustably mounted in relation to the fixed presser member or plate 76 and the

pressing surfaces

76a, 78a are biased into contact with each other by a spring mounting arm 80. As seen best in Fig. 2, the spring mounting arm 81) is secured to the base or bed plate of the machine and has a downwardly biasing effect on the movable presser plate 78. The bias is selected such that materials of various thickness may be received between the contacting

pressing surfaces

76a, 78a, yet an adequate pressing effect obtained.

Associated with the movable presser plate or member '78 is an appropriate heating element 84, seen best in Fig. 10, which is illustrated as a coil supported in a heat-conducting but electrically non-conductive body and in heat-transfer relation to the presser plate 78. The details of the heating element for the presser plate are unimportant and the movable presser plate has been illustrated as the one which is heated only for the sake of convenience. It is to be expressly understood that various other types of heating means are equally within the contemplation of the present invention.

The

presser members

76, 78 of the margin-turning and pressing section 70 are formed with an entry mouth 86 which extends along an arcuate path from the base line or apical line 740 of the channelway 74 and toward one side of the

presser members

76, 78. The mouth 86 is of progressively decreasing cross-section at locations laterally offset from the base 740 of the channel 74 and is made up of like camming surfaces 86a, 86b which are curved concavely and merge to define the mouth 86 of diminishing sections at locations removed laterally of and to the leftof the channel 74,-as viewed inFigs. 2 and The seam-opening and turning mechanisms 64 further comprise a tongue assembly which includes a horizontally-extending L-shaped supporting bracket 92 pivoted on a stud or pin 94 for rocking movement in a plane spaced generally above the feed bed of the machine. Pivotally supported on the end of the L-shaped bracket remote from the stud or pin 94 is a thin blade 96 which extends generally in a horizontal plane and is rockably supported by a pin 98 for angular adjustment in the horizontal plane.

The blade 96 is spaced generally above the plane of the feed bed and lies in substantially coplanar relation with the apical line 740 of the channelway 74. The plate or tongue 96 bridges or straddles the channelway 74 and the fixed and

movable press plates

76, 78 and is of a length such that the seam s is positively guided in its movement past the spreader section 66, the seam-opening and turning section 68 and the seam-pressing section 70. The blade 96 is fabricated of a springy material and is sufliciently thin such that it may be accommodated between the upper and lower layers m1, me of the body proper and engaged along the inner side of the seam s to positively guide the same in relation to the camming surfaces 74a, 74b, the camming surfaces 86a, 86b and the pressing surfaces 76a, 76b. The portion of the blade 96 which extends into the channelway and bears against the seam directly opposite the apical line 740 of the converging camming surfaces 74a, 74b assures the perfect functioning of these camming surfaces in spreading and turning of the marginal portions 21, 12 immediately contiguous to the seam and contributes materially to the formation of a flat open seam. In that the blade is of relatively thin material, its presence between the material layers does not appreciably increase their thickness. The presence of the blade 96 between the leading portions of the

pressing members

76, 78 does not interfere with the pressing action and assures that the folded-back portions 21, 122 will not creep in relation to each other. When the goods passes beyond the end of the blade 96 the

presser members

76, 78 have already completed the pressing operation.

As previously pointed out, the contact plane of the

pressing surfaces

76a, 78a is spaced below the plane of the apical line 740 of the channelway 74. This spacing is selected of the order of twice the maximum thickness of materials to be employed in conjunction with the described seam-opening mechanisms. Thus, the

sections

68, 70 are disposed in relation to each other to accommodate materials of different thickness in the selected range. For material somewhat thinner than this maximum thickness, it is to be noted that the blade 96 may be somewhat distorted by the biasing effect of the movable presser plate 78 and permits the desired seam-opening and pressing action.

In review, the mechanisms 64 are progressively effective to spread the margins p1,pz (see Fig. 7), to cause the margins p1, p2 to diverge slightly with respect to each other and from the seam s (see Fig. 8), to assume a position substantially at right angles to the body of the tube with the guide wire 42 against the outer side of the seam s and the flexible blade or tongue 96 against the inner side of the seam .9 (see Fig. 8a), to turn the margins back over the seam s and toward the adjacent layers m1, m2 of the tube (see Fig. 9), and finally to complete the opening of the seam s by pressing the margins back into superposed relation with the body (see Fig. 10).

A troublesome problem in connection with seam-opening has been that of detecting a break in either the thread passing through the needle 26 or the thread emanating from the bobbin of the sewing apparatus. Although thread-discontinuity devices are broadly known to the art, such devices inherently are rather complicated. The application of such devices to the formation of a seamed tube of goods in which their marginal portions are folded back upon the seam, is further complicated in that the seam is not visible. Practical experience indicates that the machine will appear to be operating properly even upon the occurrence of a break in either of the threads and the operator will not be able to tell that the tube is not being stitched. That is, the folder or seam-opening mechanisms 64 will still be elfective to turn back the marginal portions even though the seam is not being formed. In accordance with a feature of the present invention, and as seen in Fig. 3, a seam-discontinuity sensing system 101) is provided which includes a microswitch 102 arranged to close a signalling means, illustrated as a light 1% which may be disposed on the feed bed of the machine at a location easily seen by the operator. The microswitch 102 has an actuator 102a which is closed in response to clockwise rocking movement of the L-shaped bracket 92 about the pivot 94. The bracket 92 supports a horizontaliy extending switch-operating arm 106 which carries a contact member 168 in cnd-to-end alignment with the actuator 102a of the microswitch 192. The contact member 198, in the form of a threaded screw, is selectively adjustable with relation to the actuator 102a. The contact member 198 is disposed such that the switch 1% remains open in a normal condition which corresponds to the plate or blade 96 being spaced from the apical line 740 of the channelway due to the interposed line of stitching s. Upon the occurrence of a break in the stitching, the blade 96 will move slightly in a clockwise direction, that is to the right in Fig. 3, under the biasing effect of the spring 110. This movement is transmitted via the connecting arm Hi6 into a throw of the contact member 1 33 and causes the microswitch to close and to operate the alarm or indicator circuit 104.

For the sake of convenience in access to the seamopening and turning mechanisms 64, the spring 110 is mounted in relation to the pivot 94 such as to obtain a toggle action support for the tongue assembly 90. Accordingly, the bracket 92 may be tripped from the full line operative position illustrative in Fig. 3 to the broken line or retracted position which permits ready access both to the sewing and folding mechanisms.

The details of the wind-up or pulling mechanisms are best illustrated in Figs. 1 and 11 to 14 inclusive. The wind-up or pulling mechanisms include a pair of pulling

rollers

112, 114 which extend across the width of the machine at the exit end of the seam-forming and opening station 12. As seen best in Fig. l, the pulling roller 112 has a knurled or roughened periphery while the pulling roller 114 has a smooth periphery. The roller 112 is supported on a horizontal shaft 116 which is journaled in appropriate sleeve bearings 118. The bearings or supports for the shaft 116 are carried on a bracket including arms 12% which are pivotally supported on the frame of the machine rearwardly or" the station 12. As seen in Fig. 12, the bracket 1213 is adjustably securable in relation to the frame to support the roller 112 in various positions of vertical adjustment relative to the feed bed of the machine. The roller 114 is likewise supported on a shaft 122 which is journaled in sleeve bearings 124 supported on a suitable pivoted bracket including arms 126. The roller 11d rests upon the roller 112 with a peripheral line contact and may be displaced relative to the latter by suitable mechanisms for rocking the roller 114 about its pivotal support. For example, and as shown best in Figs. 11 and 12, a foot-actuated lever 128 may be pivoted on the frame of the machine at an easily accessible location and connected to the arms 126 of the rockable support through a coupling rod 13%. in response to the depression of the lever 128, the bracket may be rocked in a counterclockwise direction about its pivots to space the roller 114 about and out of contact with the roller 112 to permit the tubed goods to be trained about the roller 112, between the rollers 112, 11% and about the roller 114. It is equally within the contemplation of the invention to mount the roller 114 on an appropriate vertical way and displace the same in relation to the roller 112 by a suitable handoperated eccentric.

Disposed rearwardly of the pulling

rollers

112, 114 is a wind-up assembly 132 which is specifically designed to wind up the tubed goods with the open seam on a relatively large diameter cylinder 134 appropriate for use in conjunction with the bias-cutting mechanisms described in the aforementioned copending application. The wind-up assembly 132 includes aligned

stub shafts

136, 138 which extend generally transversely of the machine. The stub shaft loosely supports a rotatable end collar or clamp 140, while a similar end collar or clamp 142 is keyed to the stub shaft 138. The assembly of the shaft 136 and the loosely journaled collar 140 are laterally adjustable on bracket 141 and may be fixed in any position of ad justnin by a set screw or the like 144. Although the coilar 142 is fixed for rotation with the stub shaft 138, the same is adjustable longitudinally of the stub shaft 138 which in turn is journaled on the frame. The end collars 146, 142 may be formed with appropriate projections or cars, such as 146, for gripping the tube 134 therebetween. it will be appreciated that the lateral disposition of the tube 13% in relation to the sewing or seam-opening mechanisms at the station 12 may be adjusted and that tubes of varying lengths may be accommodated between the end collars 14%, 142.

Drive is imparted to the stub shaft 138 from a motor 159 which is also employed as the drive for the sewing mechanisms through appropriate belt and pulley couplings, not shown. The output shaft 15% of the motor carries a sprocket 152 which is coupled by a chain 154 to the input sprocket 156 of a suitable speed reduction system 158. The output shaft 153a of the speed reduction system 158 carries a pair of concentric sprockets, one of which is coupled by a chain 164 to a slip-clutch coupling mechanism 162 for the stub shaft 138 and the other of which is coupled by a chain 164 to a pulling roller drive shaft 116. The pulling roller drive shaft 166 carries a gear 168 for driving the pulling roller 112 which gear is in meshing engagement with a further gear 170 connected to the pulling roller 114.

The slip-clutch coupling mechanism 162 includes a first coupling plate 172 which is connected to the sprocket of the chain drive 166 and loosely journaled on the stub shaft 138, a further clutch plate 174 keyed to and adjustable along the stub shaft 138, a spring 176 biasing the clutch plate 174 into contact with the clutch plate 172 and an interposed friction disc as of leather or the like 173. Other slip-clutch couplings are equally within the contemplation of the present invention.

As can be seen best in Fig. 14, the pulling

rollers

112, 114 are relieved away throughout a substantial portion of their lengths except for relatively narrow pulling sections or

bands

112a, 114a which lie along the edge of the pulling rollers in alignment with the sewing mechanisms. As is well understood in the sewing machine art, the sewing mechanisms are effective to feed goods past the needles only through approximately one-quarter of a cycle. That is, during each revolution of the machine, which corresponds to the formation of a stitch, the motion of the needle and related parts take up substantially threequarters of the cycle while the feed dog is efiective to deliver the material forwardly past the needle during approximately one-quarter of the cycle. The pulling

rollers

112, 114 are driven at a speed which is substantially equal to the average feed rate of the sewing machine. When the feed dog is not effective for forward delivery of the material, the seamed edge of the material behind the needle is eifectively held back in relation to the pulling rollers, while the edge along the fold line 1 does not experience such hold-back effect. In the event that the pulling rollers were effective throughout their lengths, there would be a tendency for uneven delivery of the material to the pulling rollers incident to the hold-back eifect along the sewed edge and substantial freedom of the goods along areas-2a the folded edge. It is to be observed that the pulling

rollers

112, 114, although of smaller section through a major portion of their lengths as compared to the narrow pulling Zone, are effective to hold back the tubed goods in relation to the windup drum to avoid uneven winding.

In turn, the wind-up assembly 132 and its associated mechanisms are driven at a speed determined by the rate of delivery of material by the pulling

rollers

112, 114. That is, at the outset the drum or cylinder 134 is driven at a speed slightly faster than the speed of the pulling rollers such that the slip clutch mechanisms 162 begin slipping at the start of Wind-up. By adjustment of the degree of slip, as determined by the tension of the spring 176, the tightness of the roll can be effectively controlled. It is to be noted that the presence of the four folded edges along the right side of the wound-up roll of goods (see Fig. 1) is effective to space the successive turns or layers of goods in relation to each other such that any wrinkles therein are not permanently pressed into the rolled tube of goods.

To facilitate the threading of the tubed goods about the drum or cylinder 134, it has been found to advantage to provide an apron or skirt 180 of cloth or the like secured to the drum 134. As may be appreciated from progressively inspecting Figs. 12 and 13, the apron or skirt or flap 186 may be wrapped over the leading end of the tubed material to effectively secure the leading end of the tubed material to the drum 134. This manner of securement is compatible with the bias-cutting equipment in which it is necessary to automatically release the innermost end of the wound roll of goods from the tube 134 after the same has gone through the bias-cutting equipment. This facilitates bias cutting of the end portion of the roll without fouling or stopping of the biascutting mechanisms. The described arrangement of the flap 186 provides a simple means for effecting a securemnt at the beginning of wind-up, and for automatically causing the release of the innermost end of the tube as the material is unwound in the bias-cutting machine.

A typical cycle of operations will now be described in detail to facilitate a more thorough understanding of the present combined stitching, folding, pressing and Wind-up mechanisms:

The goods in bolt form or the like are supported at a location forwardly of the pretensioning system 14 shown in Fig. 1 and then delivered to the pretensioning system in folded condition with the superposed layers m1, m2 folded about the fold line 1 and with their free edges in substantial registry. The leading end of the material is threaded on opposite sides of'the tensioning bar 46-, over the tensioning bar 48, under the tensioning bar 50, and on opposite sides of the tensioning bar 52, beneath and about the pulling roller 112, between the pulling

rollers

112, 114, and beneath and about the wind-up drum or cylinder 134. As previously pointed out, the pulling

rollers

112, 114 may be effectively separated by stepping down on the foot treadle associated with the lever 128; while the free or leading end of the goods is secured to the drum 134 by the flap or apron 180. During the initial threading operation, the seam-stitching and opening mechanisms are effective such that the leadin or threading portion of the tube is stitched along its edge and the same opened. 1

Depending upon the width of the superposed layers m1, m2 of the material, appropriate lateral adjustments of the

follding members

54, 56 is achieved such that a minimum amount of material is disposed to the right of the needle 26 for trimming and opening. As is well understood, the amount of material required to the right of the seam s may be of the order of 7 of an inch.

After the initial adjustment and threading, the operator may begin the stitching of a length of goods. In that the orientation of the free edges of the material M in relation to the needle is initially established by threading through the tensioning system 14, it is not necessary for the operator to do much more than run the sewing" machine through its foot treadle control and more or less guide the material with the free edges in registry toward the tensioning system 14. Although the operator may pull unevenly on the upper and lower layers m1, m2, such pulls are not eifectively transmitted beyond the tensioning bar 52 due to the isolating effect of the tensioning system 14. The goods entering the sewing station 12 are uniformly held back by the tensioning system and pulled along the seam edge by the pulling scetions 112a, 114a of the pulling

rollers

112, 114. Thus, although there is a greater pulling effect along the seam edge due to the operation of the feed dog, the material passing through the sewing zone has substantially uniform tension from right to left.

As the material enters the sewing and seam-opening station 12, the lower layer extends beneath the plateaued portion 44a of the bracket 44 while the upper layer passes above said portion. Thus, the material is immediately brought above and below the guide wire 42 which is to lie along the outer edge of the seam s at locations past the sewing point. After the goods are sewn and enter the seam-opening, turning, and pressing mechanisms, the seam is accurately guided at one side by the guide wire 42 which merges into the apical line of the channel 74 and at the opposite side by the thin blade 96 of the tongue assembly and tensioned across its width by the spring wire 56 of the tensioning system. Thus, after the stitched assembly leaves the needle, due to the action of the blade 96, the mechanism 64 and the guide Wire 42, the seam is accurately guided both right and left. In that the blade is pivotally supported for angular adjustment in the plane of the apical line 740 of the channel 74, the same is automatically adjustable in relation to the channel under the biasing effect of the spring 110. As seen in Fig. 8 where the guide wire 42 terminates in the upstanding face of the spreading section 66, the marginal portions p1, p2 are guided to opposite and diverging surfaces of the spreader section 66 at the leading edge 72 thereof. Ultimately, and as seen in Fig. 8a taken at the trailing edge of the spreader section 66, the marginal portions are cammed into substantial end-to-end alignment with respect to each other and at right angles to the body of the tube. Thereupon, the marginal portions enter into the channelway 74 which partially turns the marginal portions back upon the body portion of the tube, as seen in Fig. 9. This turning action is exceptionally complete and occurs at location-s immediately adjacent to the seam s due to the action of the blade 96 which is biased toward and seats itself against the apex 740 of the channel 74. In that the channel 74 is only effective to partially turn back the seam, goods of varying thicknesses may be accepted therein with equal success.

As the goods leave the trailing end of the channel 74, and while still positively engaged along the inner Side of the seam by the blade 96, the marginal portions enter into the mouth 86. The convex and merging cam surfaces 86a, 86b of the mouth 86 tend to substantially complete the turning of the marginal portions toward each other. Finally, the camming surfaces 86a, 86b merge into the contact faces 76a, 78a of the

presser plates

76, 78 where the pressing action occurs. The action of the merging surfaces 86a, 86b which are angularly related to the feed path of the seam, is to wipe close the turned back margins beginning at a location adjacent the stitch line. When wiped closed, the margins then enter the pressing section 70. Although goods of varying thicknesses may be presented to the presser section, the spring mounted and vertically adjustable presser plate 78 follows such thickness variations. Further, the margins are still positively guided in relation to the presser members despite thickness variations due to the spacing of the

contact plane

76a, 78a in relation to the apicial line 740 of the channel and the flexibility of the blade 96. Thus, it will be appreciated that the marginal portions are posi- 11 tively guided throughout the turning action and until the pressing is completed with the seam continuously opened throughout its length and to a maximum depth.

As the tubed goods emanate from the sewing station 12 at a rate determined by the drive of the feed dog, the tubed goods are uniformly pulled by the action of the rollers 112 and 11 i and ultimately delivered to the windup drum 134. After a roll is formed, it is a relatively simple matter to release the wind-up drum 134 from the end collars Mil, 142 such that the wind-up drum 134 may then be transported to bias-cutting apparatus for further operations on the goods.

As a further feature of the invention, it may be desirable when working with certain types of materials to incorporate a hold-back spring 132 in the pretensioning system 14, as shown in Fig. l. The spring :82 is adapted to bear against the material M at locations where it is wrapped around the fold-forming member 54 to exert a retarding force along the side of the tube opposite from the location which the operator grasps the material during feed toward the pretensioning system 14. it is to be understood that the hold-back spring 1&2 is optional, and is only required with certain types of materials.

From the foregoing detailed description, it may be up prcciated that apparatus according to the present invention assures the reliable feed and take-up of material in relation to the sewing, seam-opening and turning mechanisms of station 12. From the operators standpoint, little or no skill. is required to assure tandem feed of the upper and lower layers of the tube-forming material to the sewing mechanisms. Further, the operator is not required to constantly observe the position of the free edges of the tube-forming material in relation to the needle to obtain minimum selvage. In fact, the operator having once established the initial feed path of the goods in relation to the sewing mechanisms, merely guides the same toward the pretensioning system and the mechanisms are automatically effective to assure registering feed of the material past the sewing mechanisms with minimum margins to be cut off by the trimmer. The seam-opening and turning mechanisms are continuously effective to open the seam, and there is assurance that both the upper and lower margins of the seam will be turned back to a maximum extent. The positive engagement of the seam from the sewing point to the location at which the seam is pressed assures not only the opening of the seam but the final fixing of the same in the open condition. Even if the seam does have a tendency to spring back, for example after pressing and during wind-up, the presence of the permanent creases formed into the opening and pressing operations will result in an open seam when the goods are ultimately bias cut. Further, the seam opening mechanisms are arranged to accommodate materials of the varying thicknesses and qualities normally encountered in the manufacture of bias cut goods, Still further, the wind-up mechanisms assure reliable wind-up of the goods without the formation of permanent creases along the width of the tube and in a manner which is compatible for use in bias-cutting equipment.

There has been described an excellent, but nonetheless illustrative embodiment of the present invention and emphasis has been placed upon the various advantages accruing from the use of such embodiment. However, a range of alternative modifications, omissions and additions will be readily apparent to those skilled in the art, and in certain instances, some features of the invention may be used without a corresponding use of other features. Accordingly, it is appropriate that the appended claims be accorded a latitude of interpretations consistent with the spirit and scope of the present invention.

What I claim is:

l. A device for opening a seam in a tube of goods which is formed by stitching together folded and superposed layers of the goods comprising seam-opening means formed with longitudinally-extending camming surfaces,

the spacing of said camming surfaces varying through their lengths whereby the margins of said tube outwardly of said seam are spread apart and partially turned back on said superposed layers, margin-turning means includfixed and movable pressure members having flat faces in contact over a substantial area and arranged to complete the turning back of said margins into abutting relation with the adjacent layers of said goods, a thin flat tongue bridging said seam-opening and margin-turning means, said tongue extending between portions of said camming surfaces and between and in substantial contact with said flat faces of said pressure members for positively guiding the seamed tube in relation to said seam-opening and margin-turning means, and a guide interposed between said seam-opening means and said margin-turning means and cooperating with said tongue for positively guiding the seamed tube during its traverse between said seam-opening means and said margin-turning means, said seam-opening means, said margin-turning means and said guide being in alignment and in adjacent relationship with each other whereby the turned margins are continuously guided and engaged.

2. A device for opening a scam in a tube of goods which is formed by stitching together folded and superposed layers of the goods comprising seam-opening means formed with longitudinally-extending camming surfaces, said camming surfaces being arranged to define a channelway whereby the margins of said tube outwardly of said seam are partially turned back on said superposed layers, margin-turning means including fixed and movable pressure members having an entry mouth of decreasing cross-section, said margin-turning means having flat faces abutting with substantial area contact in a plane and being arran ed to complete the turning back of said margins into abutting relation with the superposed layers of said goods, a thin flat tongue disposed in said plane and bridging said seam-opening and margin-turning means, said tongue extending into said channelway, through said entry mouth and between said flat faces of said pressure members for positively guiding the seamed tube in relation to said seam-opening and margin-turning means, and a guide interposed between said seam-opening means and said margin-turning means and cooperating with said tongue for positively guiding the seamed tube during its traverse between said seam-opening means and said margin-turning means, said seam-opening means, said marginturning means and said guide being in alignment and in adjacent relationship with each other whereby the turned margins are continuously guided and engaged.

3. A device for forming and opening a seam at one side of a tube of goods comprising a seam-forming and opening region, means for pulling said tube through said region, means for pretensioning said tube in advance of said region, the pulling and pretensioning means serving to maintain uniform tension on said tube across its width during movement through said region, sewing mechanisms in said region for stitching along said one side of said tube, and seam opening, turning and pressing means trailing said sewing mechanisms in said region and including a guide wire adapted to lie against the outer side of the seam and between margins to be turned back on the body of said tube, a fixed turning member formed with a longitudinal guideway in alignment with said guide wire, fixed and movable presser members having abutting flat contact faces and following said turning member, said fixed and movable presser members being formed with camming surfaces for engaging said margins after egress from said guideway, said camming surfaces approaching each other and merging into said contact faces, a thin tongue adapted to lie against the inner side of said seam and within the body of said tube, said tongue extending into said guideway, between said camming surfaces, and between said contact faces in substantial area contact therewith, and a guide interposed between said seamopening means and said margin-turning means and cogasses operating with said tongue for positively guiding the seamed tube during its traverse between said seam-opening means and said margin-turning means, said seamopening means, said margin-turning means and said guide being in alignment and in adjacent relationship with each other whereby the turned margins are continuously guided and engaged.

4. A device for forming and opening a seam at one side of a tube of goods comprising a seam-forming and opening region, means for pulling said tube through said region, means for pretensioning said tube in advance of said region, the pulling and pretensioning means cooperating to maintain uniform tension on said tube across its width during movement through said region, and seam opening, turning and pressing means in said region and including a guide wire adapted to lie against the outer side of the seam and between margins to be turned back on the body of said tube, a margin-turning member formed with a longitudinal guideway in alignment with said guide wire, fixed and movable presser members having flat contact faces abutting with substantial area contact in a plane and following said turning member, camming surfaces for engaging said margins after egress from said guideway and directing said margins between said presser members, said camming surfaces approaching each other and merging into the plane of said contact faces, a thin flat tongue adapted to lie against the inner side of said seam and within the body of said tube, said tongue extending into said guideway, between said camming surfaces, and between and in engagement with said contact faces, and a guide interposed between said seamopening means and said margin-turning means and cooperating with said tongue for positively guiding the seamed tube during its traverse between said seam-opening means and said margin-turning means, said seamopening means, said margin-turning means and said guide being in alignnment and in adjacent relationship with each other whereby the turned margins are continuously guided and engaged.

5. A device according to claim 4 wherein the means for pretensioning includes a plurality of tensioning bars extending transversely of said tube, said tensioning bars being arranged to define sinuous paths for said tube of goods.

6. A device according to claim 5 wherein said sinuous path includes first and second runs of similar curvature and oppositely directed from a reference plane.

7. A device according to claim 4 wherein the guideway in said margin-turning member is of V-shaped cross-section with its apical line coinciding with said guide wire.

8. A device according to claim 4 including a pivotal mount for said tongue.

9. A device for forming and opening a seam at one side of a tube of goods comprising a seam-forming and opening region, means for pulling said tube through said region, means for pretensioning said tube in advance of said region, the pulling and pretensioning means cooperating to maintain uniform tension on said tube across its width during movement through said region, sewing mechanisms arranged along a linear fed path in said region for stitching along said one side of said tube, and seam opening, turning and pressing means trailing said sewing mechanisms in said region, said pulling means including tube-engaging rollers extending across said region, said rollers contacting each other only along peripheral portions in substantial alignment with said linear feed path whereby pulling force is exerted only along said linear feed path, the remaining peripheral portions of said rollers being spaced apart whereby no pulling force is exerted along said remaining peripheral portions, yet the goods is supported.

10. The combination with a sewing machine including a needle movable through a stitch-forming stroke and a feed dog movable through a forward feeding stroke, of a guide wire extending along a linear path past said needle and feed dog, said guide wire being adapted to lie against the outer side of a seam formed in superposed layers of material and between marginal portions to be turned back on said superposed layers, a spreader member in alignment with said guide wire and along said path, said spreader member being of progressively increasing crosssection for parting said marginal portions, a seam-opening member formed with a longitudinal channel following said spreader member, said channel having a V-shaped crosssection and including converging walls extending inwardly and meeting along an apical line substantially in end to end alignment with said guide wire, the section of said channel being selected to turn back said marginal portions toward said superposed layers, margin-turning means including fixed and movable pressure members having flat contacting faces coextensive for a substantial area and arranged to complete the turning of and to press said folded back margins into superposed relation with the adjacent layers of said goods, and a thin tongue bridging said seam-opening and seam-turning means, said tongue extending into said channel in the plane of said apical lane and between said pressure members for positively guiding said goods in relation to said seam-opening and margin-turning means.

11. A device for opening a seam in a tube of goods which is formed by stitching together folded and superposed layers of the goods comprising a seam-opening channel formed with lo-ngitudinally-extending camming surfaces, the spacing between said camming surfaces diminishing from the leading end of said channel to the trailing end thereof whereby the margins of said tube outwardly of said seam are spread apart and partially turned back on said superposed layers, margin-turning means including fixed and movable pressure members having flat contacting faces abutting with substantial area contact in a plane and arranged to complete the turning back of said margins against the adjacent layers of said goods, a thin flat tongue extending substantially in the plane of said contacting face and bridging said seamopening channel and margin-turning means, said tongue projecting laterally into said channel and extending longitudinally between portions of said camming surfaces and between said contacting faces of and in substantial area contact with said pressure members for positively guiding the seamed tube in relation to said seam-opening channel and margin-turning means, and margin-guiding means interposed between said seam-opening channel and said margin-turning means and cooperating with said tongue to guide the margins after egress from said seamopening channel until entry between said flat contacting faces of said pressure members, said seam-opening channel, said margin-turning means and said margin-guiding means being in alignment and in adjacent relationship whereby the turned margins are continuously guided and engaged.

12. A device for opening a scam in a tube of goods which is formed by stitching together folded and superposed layers of the goods comprising a seam-opening channel formed with longitudinally-extending camming surfaces, the spacing between said camming surfaces diminishing from the leading end of said channel to the trailing end thereof whereby the margins of said tube outwardly of said seam are spread apart and partially turned back on said superposed layers, margin-turning means including fixed and movable pressure members having flat contacting faces abutting with substantial area contact in a plane and arranged to complete the turning back of said margin-s against the adjacent layers of said goods, heater means in heat transfer relation to at least said movable pressure member, a thin flat tongue extending substantially in the plane of said contacting face and bridging said seam-opening channel and margin-turning means, said tongue projecting laterally into said channel and extending longitudinally between portions of said camming surfaces and between portions of said contacting faces of said pressure members for positively guiding the seamed tube in relation to said seam-opening channel and margin-turning means, and margin-guiding means interposed between said seam-opening channel and said margin-turning means and cooperating with said tongue to guide the margins after egress from said seam-opening channel until ent y between said flat contacting faces of said pressure members, said seam-opening channel, said margin-turning means and said margin-guiding means being in alignment and in adjacent relations ip whereby the turned margins are continuously guided and engaged.

13. A device for opening a seam in a tube of goods which is formed by stitching together folded and superposed layers of the goods comprising a seam-opening channel formed with longitudinally-extending camming surfaces, the spacing between said camming surfaces diminishing from the leading end of said channel to the trailing end thereof whereby the margins of said tube outwardly of said seam are spread apart and partially turned back on said superposed layers, margin-turning means including fixed and movable pressure members having flat contacting faces abutting with substantial area contact in a plane and arranged to complete the turning back of said margins against the adjacent layers of said goods, spring means operatively connected to said movable pressure member and biasing said movable pressure member toward said fixed pressure member, a thin flat tongue extending substantially in the plane of said contacting face and bridging said seam-opening channel and margin-turning means, said tongue projecting laterally into said channel and extending longitudinally between portions of said camming surface and between said contacting faces of said pressure members for positively guiding the seamed tube in relation to said seam-opening channel and margin-turning means, and margin-guiding means interposed between said seam-opening channel and said marginturning means and cooperating with said tongue to guide the margins after egress from said seam-opening channel until entry between said flat contacting faces of said pressure members, said seam-opening channel, said margin-turning means and said margin-guiding means being in alignment and in adjacent relationship whereby the turned margins are continuously guided and engaged.

14. A device for opening a seam in a tube of goods which is formed by stitching together folded and superposed layers of the goods comprising a seam-opening channel formed with longitudinally-extending carnming surfaces, the spacing between said carnming surfaces diminishing from the leading end of said channel to the trailing end thereof whereby the margins of said tube outwardly of said seam are spread apart and partially turned back on said superposed layers, margin-turning means including fixed and movable pressure members having fiat contacting faces abutting with substantial area contact in a plane and arranged to complete the turning back of said margins against the adjacent layers of said goods, a heater element assembled in heat transfer relation to said movable pressure member, spring means operatively connected to said movable pressure member and biasing said movable pressure member toward said fixed pressure member, a thin flat tongue extending substantially in the plane of said contacting face and bridging said seam-opening channel and margin-turning means, said tongue projecting laterally into said channel and extending longitudinally between portions of said camming surfaces and between said contacting faces of said pressure members for positively guiding the seamed tube in relation to said seam-opening channel and margin-turning means, and margin-guiding means interposed between said seam-opening channel and said margin-turning means and cooperating with said tongue to guide the margins after egress from said seam-opening channel until entry between said flat contacting faces of said pressure members, said seam-opening channel, said margin-turning means and said margin-guiding means being in alignment and 15 in adjacent relationship whereby the turned margins are continuously guided and engaged.

15. In a device for forming and opening a scam in a length of material having a fold and registering edges, a seam-forming and opening region, means engaging said material along said registering edges for Pulling said material through said region, means extending between said fold and said registering edges for pretensioning said material in advance of said region, the pulling and pretensioning means serving to maintain uniform tension on said material between said fold and said registering edges during movement of said material through said region, sewing mechanisms in said region for stitching along said registering edges to form a tube of said material, and seam opening, turning and pressing means trailing said sewing mechanisms in said region and including a guide wire adapted to lie against the outer side of the seam and between margins of the material to be turned back on the body of said tube, a fixed turning member formed with a longitudinal guideway in alignment with said guide wire, fixed and movable presser members following said turning member and having abutting flat contact faces, said fixed and movable presser member being formed with camming surfaces for engaging said margins after egress from said guideway, said camming surfaces approaching each other and merging into said contact faces, and a thin flat tongue disposed substantially in the plane of said contact faces and adapted to lie against the inner side of said seam and within the body of said tube, said tongue extending laterally into said guideway and longitudinally between said camrning surfaces, and between and in substantial area contact with said contact faces.

16. In a device according to claim 15, means mounting said tongue for pivoted movement in the plane of said contact faces, and a spring operatively connected to said tongue and biasing said tongue inwardly against the inner side of said seam.

17. In a device according to claim 16, a seam discontinuity detector including an alarm device having a movable actuator, and means operatively connected to said tongue and operatively disposed relative to said actuator in response to inward movement of said tongue past the location of said seam.

18. The combination with a sewing machine including a needle movable through a stitch-forming stroke and a feed dog movable through a forward feeding stroke, of a guide wire extending along a linear path past said needle and feed dog, said guide wire being adapted to lie against the outer side of a seam formed in superposed layers of material and between marginal portions to be turned back on said superposed layers, a seam-opening member formed with a longitudinal channel having a V-shaped cross-section and including converging walls extending inwardly and meeting along an apical line substantially in end to end alignment with said guide wire, the section of said channel diminishing from its leading end to its trailing end to turn back said marginal portions toward said superposed layers, margin-turning means including fixed and movable pressure members abutting with substantial area contact in a plane and arranged to complete the turning of and to press said folded back margins into superposed relation with the adjacent layers of said goods, a thin tongue bridging said seam-opening and seam-turning means, said tongue extending laterally into said channel and betweensaid pressure members and longitudinally between said channel and said pressure members for positively guiding said goods in relation to said seam-opening and margin-turningmeans, said tongue being disposed in coplanar relation with said apical line and having a leading edge substantially coextensive with said apical line, and a pivoted mount for said tongue whereby the latter is angularly adjustable relative to said channel.

19. In combination with a sewing machine including a needle movable through a stitch-forming stroke and a feed dog movable through a forward feeding stroke, a

guide wire extending along a linear path past said needle and feed dog, said guide wire being adapted to lie against the outer side of a seam formed in superposed layers of material and between marginal portions to be turned back on said superposed layers, a seam-opening member formed with a longitudinal channel having a section diminishing from its leading end to its trailing end to turn back said marginal portions toward said superposed layers, marginturning and pressing means including fixed and movable pressure members abutting with substantial area contact in a plane and arranged to complete the turning of and to press said folded back margins into superposed relation with the adjacent layers of said goods, a thin tongue bridging said seam-opening and seam-turning means, said tongue extending laterally into said channel and between said pressure members and longitudinally between said channel and said pressure members for positively guiding said goods in relation to said seam-opening and marginturning means, and means for maintaining uniform tension in said material during the forming and opening of said seam, said last named means including pulling rollers having contacting peripheral portions along said scam, the remaining peripheral portions of said pulling rollers being spaced apart yet serving to support the goods, and pretensioning bars extending across the width of the superposed layers and through which the superposed layers are threaded prior to feed to said sewing machine.

20. In combination with means for forming and opening a stitched seam at one side of a folded length of goods, the forming and opening means including a fixed turning member having a longitudinal guideway, a flat blade adapted to be received between superposed portions of said folded length and lie in a plane and bear against the inner side of the stitched seam, said blade extending into said fixed turning member and normally being spaced in relation to said fixed turning member due to the presence of said stitched seam, a pivoted support for said blade mounting said blade for rocking movement in said plane, a spring biasing said blade to bear against said seam, seam-discontinuity sensing means, and actuating means for said sensing means and operatively connected to said blade and operable upon movement of said blade toward said fixed turning member under the influence of said spring and in response to the occurrence of a break in said stitched seam.

21. In the combination according to claim 20, said seamdiscontinuity sensing means including a visual indicator having an energization circuit, and means for completing said circuit controlled by movement of said blade toward said fixed turning member.

22. In combination with means for forming and opening a seam along a stitching path, at one side of a folded length of goods, means for pretensioning said goods in advance of said forming and opening means, the pretensioning means including fold-forming members in end to end relation along a line spaced from and extending parallel to said stitching path and having their adjacent ends spaced apart, and at least a pair of pretensioning bars extending substantially at right angles to said fold-forming members, said pretensioning bars being secured at one end to the adjacent ends of said fold-forming members, whereby the goods may be folded about said fold-forming members and threaded through said pretensioning bars.

23. In the combination according to claim 22, one of said fold-forming members being of resilient material and extending from said pretensioning bars for the extent of the means for forming and opening the seam.

24. A device according to claim 22 including a further set of pretensioning bars between and parallel to said first named set of pretensioning bars, the respective sets of pretensioning bars being arranged to define a sinuous feed path for the folded length of goods.

25. In combination with means for forming and opening a seam along a stitching path at one side of a folded length of goods, means for pretensioning said goods in advance of said forming and opening means, the pretensioning means including a pair of fold-forming members arranged in end to end relation in a plane spaced from and parallel to said stitching path and having their adjacent inner ends spaced apart, a first pretensioning bar extending at right angles to said fold-forming members and secured at one end to the inner end of one of said fold-forming members, a second pretensioning bar extending at right angles to said fold-forming members and secured at one end to the inner end of the other of said fold-forming members, said second pretensioning bar being disposed in a plane above said first pretensioning bar, third and fourth tensioning bars interposed between said first and second tensioning bars and extending parallel thereto, and mounting means operatively connected to said third and fourth tensioning bars.

26. In combination with means for forming and opening a seam along a stitching path at one side of a folded length of goods means for pretensioning said goods in advance of said forming and opening means, the pretensioning means including a pair of fold-forming members arranged in end to end relation in a plane spaced from and parallel to said stitching path and having their adjacent inner ends spaced apart, a first pretensioning bar extending at right angles to said fold-forming members and secured at one end to the inner end of one of said fold-forming members, a second pretensioning bar extending at right angles to said fold-forming members and secured at one end to the inner end of the other of said fold-forming members, said second pretensioning bar being disposed in a plane above said first pretensioning bar, third and fourth tensioning bars interposed between said first and second tensioning bars and extending parallel thereto, mounting means for said third and fourth tensioning bars, said third and fourth tensioning bars having their centers arranged in a reference plane, the upper peripheral surface of said first tensioning bar being tangential to said reference plane, the lower peripheral surface of said second tensioning bar being tangential to said reference plane.

27. A device for opening a seam in a tube of goods which is formed by stitching together folded and superposed layers of the goods comprising seam-opening means formed with longitudinally extending camming surfaces meeting along an apical line, the spacing of said camming surfaces varying through their lengths whereby the margins of said tube outwardly of said seam are spread apart and partially turned back on said superposed layers, margin-turning means including fixed and movable pressure members having flat faces in contact over a substantial area, said flat faces being disposed in a plane spaced above said apical line and arranged to complete the turning back of said margins into abutting relation with the adjacent layers of said goods, the spacing between said plane and said apical line being substantially equal to twice the maximum thickness of the various goods to be formed into tubes, a thin flat tongue bridging said seam-opening and margin-turning means, said tongue extending between portions of said camming surfaces and between and in substantial contact with said fiat faces of said pressure members for positively guiding the seamed tube in relation to said seam-opening and margin-turning means, and a guide interposed between said seam-opening means and said margin-turning means and cooperating with said tongue for positively guiding the seamed tube during its traverse between said scarriopening means and said margin-turning means, said seam-opening means, said margin-turning means and said guide being in alignment and in adjacent relationship with each other whereby the turned margins are continuously guided and engaged.

28. In combination with means for forming and opening a stitched seam at one side of a folded length of goods, the forming and opening means including a fixed turning member having a longitudinal guideway, a flat blade adapted to be .received between superposed portions of said folded length and lie in a plane and bear against the inner side of the stitched seam, said blade extending into said fixed turning member and normally being spaced in relation to said fixed turning member due to the presence of said stitched seam, means operatively connected to said blade mounting said blade for movement in said plane, a spring biasing said blade to bearagainst said seam, seam-discontinuity sensing means, and actuating means for said sensing means and operatively connected to said blade and operable upon move- .ment of said blade toward said fixed turning member under the influence of said spring and in response to the occurrence of a break in said stitched seam.

29. In the combination according to claim 28, said seam-discontinuity sensing means including a visual indicator having an energization circuit, and means for completing said circuit controlled by movement of said blade toward said fixed turning member.

30. In combination, a device for forming and opening a seam at one side of a tube of goods, said device including sewing mechanisms arranged along a feed path for stitching along said one side of said tube and means trailing said sewing mechanisms along said feed path for opening said seam, a windup device arranged rearwardly of said sewing mechanisms in which the seamed tube is rolled up, said Windup device including a pair of pulling rollers extending at right angles to said feed path and including pulling zones effective substantially along said feed path, the remaining portions of said pulling rollers being spaced apart for supporting the seamed tube without being effective to pull the seamed tube, and means operatively connected to said pulling rollers for driving the same at a peripheral speed substantially equal to the average feed rate of said sewing mechanisms.

31. In combination, a device for forming and opening a seam at one side of a tube of goods, said device including sewing mechanisms arranged along a linear feed path for stitching along said one side tube and means trailing said sewing mechanisms for opening said seam, a windup device in which said tube is rolled up, said windup device including a pair of pulling :rollers extending at right angles to said path and including pulling zones eifective only along said path, the remaining portions of said pulling rollers being spaced apart for supporting goods without being effective to pull said goods, means operatively connected to said pulling .rollers for driving the same at a peripheral speed substantially equal to the average feed rate of said stitching mechanisms, and rewinding means arranged 'rearwardly ofsaid pulling rollers for receiving the tube of goods in roll form.

32. "In combination, a device for forming and opening a seam at one side of a tube of goods, said device in cluding sewing mechanisms arranged along a linear feed path for stitching along said one side tube and means trailing said sewing mechanisms for opening said seam, a windup device in which said tube is rolled up, said windup device including a pair of pulling rollers extending at right angles to said path and including pulling zones effective only along said path, the remaining portions of said pulling rollers being spaced apart for supporting goods without being effective to pull said goods, means operatively connected to said pulling rollers for driving the same at a peripheral speed substantially equal to the average feed rate of said stitching mechanisms, and rewinding means arranged rearwardly of said pulling rollers for receiving the tube of goods in roll form, said rewinding means including a driving shaft, a tubular support driven by saiddriving shaft and receiving the roll of goods, and means operatively connected to said driving shaft 'for turning said tubular support at a changeable rate to achieve a constant takeup rate of the tube of goods at the outer periphery of the rewinding roll which is substantially equal to the feed rate to the rewind means as determined by the peripheral speed of said pulling rollers.

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