US3839973A

US3839973A - Sewing machine with automatic positioning of sewing head with respect to material edge

Info

Publication number: US3839973A
Application number: US00404915A
Authority: US
Inventors: D Cummins; W Jung
Original assignee: AMF Inc
Current assignee: Automated Machinery Systems Inc
Priority date: 1972-11-14
Filing date: 1973-10-10
Publication date: 1974-10-08
Anticipated expiration: 1991-10-08
Also published as: CA988782A; GB1398620A; FR2206400A1; FR2206400B1; IT1001023B; JPS49135747A; DE2356639A1

Abstract

Sewing apparatus, particularly adapted for sewing limp material, in which the material to be sewn is conveyed by a pair of perforated and spaced conveyor belts aligned in their direction of movement and riding on a pair of vacuum chambers which causes the material to press against the upper surfaces of the belts and to be maintained in correct position thereon. A needle driving mechanism located above the gap between the belts, a stitch anvil having a light reflecting tape on its upper surface and located in said gap and a loop forming mechanism located below such gap are mounted to be moved perpendicularly to the direction of belt movement under the control of photocells mounted on the housing of the needle driving mechanism. A lift plate mounted on said housing extends over the stitch anvil to direct air flow so as to lift the leading edge across said gap.

Description

United States Patent [191 Cummins et al.

[54] SEWING MACHINE WITH AUTOMATIC POSITIONING OF SEWING HEAD WITH RESPECT TO MATERIAL EDGE [751 Inventors: Donald Cummins, Hopewell;

Wilhelm H. Jung, Mechanicsville, both of Va.

[73] Assignee: AMF Incorporated, White Plains,

[22] Filed: Oct. 10, 1973 [21] Appl. No.: 404,915

[30] Foreign Application Priority Data Nov. 14, 1972 Great Britain 52550/72 52 us. Cl. 112/121.14 51 Int. Cl D05b 3/00 [58] Field of Search..... 1l2/l2l,l4, 121.15, 121.23, 112/2, 121.11, 121.12

[451 Oct. 8, 1974 OTHER PUBLICATIONS Knitted Outerwear Times, Mar. 16, 1964; pp. 4 and 5; article, New Installation Automates Overedging, Charles Reichman.

Primary Examiner-James R. Boler Attorney, Agent, or Firm-George W. Price; Martin Smolowitz r 71 ABSTRACT Sewing apparatus, particularly adapted for sewing limp material, in which the material to be sewn is conveyed by a pair of perforated and spaced conveyor belts aligned in their direction of movement and riding on a pair of vacuum chambers which causes the material to press against the upper surfaces of the belts and to be maintained in correct position thereon. A needle driving mechanism located above the gap between the belts, a stitch anvil having a light reflecting tape on its upper surface and located in said gap and a loop form ing mechanism located below such gap are mounted to be moved perpendicularly to the direction of belt movement under the control of photocells mounted on the housing of the needle driving mechanism. A lift plate mounted on said housing extends over the stitch anvil to direct air flow so as to lift the leading edge across said gap.

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sum 10 or n I *SEWINGMACHINE WITH AUTOMATIC POSITIONING or SEWING HEAD WITH RESPECT TO MATERIAL EDGE This invention relates to sewing machines and particularly to sewing apparatus for rapidly and automatically sewing limp material with stitching extending along an edge of such material at a predetermined distance from the edge thereof.

Relatively flexible or limp material, such as loosely.

woven cloth, is difficult to sew because it is difficult to guide due to its limpness. Thus, it tends to gather or twist as it approaches and passes through and beyond the sewing head. Also, if there is a gap in the sewing table, difficulties are encountered in directing it across such gap.

Frequently, it is desirable to produce a relatively long length of stitching in such material, e.g., lengthwise of the leg of a pair of slacks, and the edge thereof maynot be rectilinear. It is, of course, important from the economic standpoint that'such length of stitching be performed rapidly. Furthermore, for such purpose, it is important to avoid manual positioning of the material as it passes through the sewing head and to avoid the need for accurate positioning of the edge which would be required with programmed movement of the sewing head or the table which supports the material.

One object of the invention is to provide sewing apparatus for rapidly sewing material which apparatus is particularly adapted for sewing limp material and is relatively precise in locating the stitching with respect to the material edge even though the latter may be irregular or non-linear.

Another object of the invention is to provide sewing apparatus which automatically positions the sewing head with respect to the edge of the material and which does not require'accurate positioning of the edge of the material as it is placed on the apparatus prior to sewing thereof.

In the preferred embodiment of the invention, the sewing apparatus comprises a pair of endless conveyor belts aligned in their direction of movement. The belts are separated at their adjacent portions by a small gap in which a stitch anvil is received. The belts are perfo rated and ride over vacuum chambers which cause the limp material to be pressed against the upper surfaces of the belts and to be maintained in the correct positions thereon. A modified stitch forming mechanism is also mounted in the space between the adjacent'belt portions and below the stitch anvil. A conventional needle drive mechanism is mounted above the anvil, and such mechanism, as well as the anvil and the stitch forming mechanism, are mounted for movement transversely to the direction of movement of the belts, and hence, the direction of movement of the material to be sewn, under the control of apparatus for detecting the edge of the material. To assist in directing the material across the gap between the belts, a lift plate is provided between the sewing head and the anvil, which plate directs the air flow so as to lift the leading edge of the material across the gap and the anvil.

Other objects and advantages of the apparatus of the invention will be apparent from the following detailed description of the presently preferred embodiment thereof, which description should be considered in conjunction with the accompanying drawings in which:

FIG. 1 is an enlarged, fragmentary, perspective view of the preferred embodiment of the apparatus of the invention illustrating the sewing head, the discharge or downstream conveyor belt, a portion of the feeding or upstream conveyor belt, and portions of the vacuum chambers;

FIG. 2 is a front elevation view of the the invention;

FIGS. 3 and 4 are, respectively, plan and front elevation views of the conveyors forming part of the apparatus of the invention;

FIG. 5 is a fragmentary, enlarged, end elevation view, partly cut away, of the sewing head and a portion of the feeding belt shown in the preceding figures;

FIG. 6 is a fragmentary, enlarged, side elevation view, partly cut away, of the stitch. forming mechanism and the support therefor;

FIG. 7 is a fragmentary, enlarged, front elevation view, partly cut away, of the portion of the apparatus of the invention shown in FIG. 6 and adjacent structure; I

FIGS. 8, 9 and 10 are enlarged, fragmentary, end elevation views, respectively, of a portion of the looper and its drive, of the rocker shaft drive and the front needle guard mechanisms and of the rear needle guard mechanism, all forming part of the stitch forming mechanism shown in FIGS. 6 and 7;

FIG. 11 is an enlarged, fragmentary,' plan view of the looper drive of the stitch forming mechanism shown in FIGS. 6 and 7;

FIG. 12 is a fragmentary, enlarged, side elevation view of the thread take-up mechanism shown in FIGS. 6 and 7;

FIGS. 13-16 are diagrammatic, front elevation views of a portion of the apparatus shown in the preceding figures which illustratethe air flow in the apparatus of the invention at the adjacent portions of the conveyor belts; and

FIG. 17 is an'. electrical block diagram illustrating an embodiment of the controls for the various parts of the apparatus of the invention.

apparatus of SEWING HEAD The preferred embodiment of the sewing apparatus of the invention which is illustrated in FIGS. 1-4 comprises a sewing head 1 which may be of any conventional type and may, for example, be a Model 5528301 chain stitch sewing head of the type manufactured and sold by the Singer Manufacturing Company. The sewing head 1 comprises the mechanism necessary to reciprocate the needle bar 2 having a needle 3 secured thereto and the conventional devices used to supply thread to the needle 3. The mechanism within the sewing head 1 is driven by a motor 4. As described hereinafter, the sewing head 1 is movable in the directions indicated by the double-ended arrow 5 shown in FIG. 1.

The needle 3 of the sewing head 1- cooperates with a stitch forming mechanism 6 (FIG. 2) which, generally speaking, may be of any conventional type but is modified in shape and size so as to permit the stitch forming mechanism to fit between the adjacent portions ofendless belts 7 and 8. In the embodiment to be described herein, the stitch forming mechanism 6 is a modified conventional looper mechanism used to form a Federal stitch type No. 401, which is described in detail, for example, in the publication entitled Stitch Formation Type 401" published by the Union Special Machine Company, 400 North Franklin Street, Chicago, Ill. However, if it is desired to produce a different type of stitch, a different known type of stitch forming mechanism, modified to fit within the available space, may be used.

The needle 3, in cooperating with the mechanism 6, passes through a hole in a transparent lift plate 9, the function of which will be described hereinafter, and through a hole in an anvil 10 mounted in the gap be tween the adjacent portions of the belts 7 and 8. The

anvil 10 carries a reflecting tape 11, the function of which will be described hereinafter, and the anvil 10 as well as the lift plate 9 are mounted so as to be movable in the directions indicated by the double-ended arrow with the sewing head 1, the lift plate 9 being supported from the frame of the sewing head 1 and the anvil 10 being supported from the housing of the stitch forming mechanism 6.

As illustrated in FIGS. 2, 5 and 6, the stitch forming mechanism 6 comprises a housing 12 which supports the sewing head 1 and such housing 12 is mounted on a plate 13 which is supported by a pair of

guide rails

14 and 15 encircled by pairs of collars 16 secured to the plate 13. The collars 16 slidably receive the

rails

14 and 15 .so that the looper or stitch forming mechanism 6 and the sewing head 1 may be reciprocated in the direction indicated by the double-ended arrow 5. The position of the plate 13 is controlled by a lead screw 17 engaging a ball bearing nut 18 secured to the plate 13 by a bracket 19. The lead screw 17 is rotatable by a servo motor 20, which is reversible and controllable in the manner hereinafter described. Thus, as the lead screw 17 is rotated in one direction by the motor 20, the plate 13 and the parts supported thereby are moved in a first direction, and when the lead screw 17 is rotated in the opposite direction by the motor 20, the plate 13 and the parts supported thereby are moved in the opposite direction. The amount of movement may, for example, be about ten to twelve inches.

GARMENT CONVEYORS The belts 7 and 8 are separate endless belts which move in the direction indicated by the

arrows

21 and 22 shown in FIG. 1 and are made of mesh or perforated material so that air can pass therethrough. The belt 7 is known as a trailing or discharge belt and is located downstream of the needle 3, whereas the belt 8 is known as the leading or feeding belt and is located upstream of the needle 3. Both belts may, for example, be about 14 inches wide, belt 7 may be about 1 foot long and belt 8 may be about 4 feet long.

The belt 8 rides on the upper surface of the perforated wall 23 of a vacuum chamber 24 and is driven by a roller 25 which is connected by belt 26 to the output pulley of a variable speed gear motor 27. The belt 8 is guided by

rollers

28, 29 and 30 and passes around a nose bar 3 1.

The belt 7 is driven by a roller 32 connected by a belt 33 to the output pulley of a variable speed gear motor 34 and the belt is guided by rollers 35, 36 and 37. The belt 7 also passes around a nose bar 38 and is supported by the upper surface of the wall 39 of a second vacuum chamber 40. The

upper walls

23 and 39 of the

vacuum chambers

24 and 40 are perforated so as to permit the passage of air therethrough and such upper walls may,

, for example, be formed by perforated sheet metal.

Each of the

vacuum chambers

24 and 40 is closed except at the

upper walls

23 and 39, and except at the

exhaust outlets

45, 46 and 47 for the chamber 24 and the exhaust outlet for the chamber 40 (not shown), connected to the exhaust duct 48. The exhaust outlets are connected to a plenum chamber 49 by

flexible ducts

50, 51, 52 and 53 and the plenum chamber 49 is connected to the inlet of a centrifugal blower 54 driven by a motor 55 through a belt 56. Thus, when the blower 54 is in operation, air is drawn out of the

vacuum chambers

24 and 40 causing air to flow into such chambers through belts 7 and 8 and the

upper walls

23 and 39. The rate at which air is exhausted from the

chambers

24 and 40 is dependent upon the force with which it is desired to hold the material to be sewn against the belts 7 and 8, and it has been found that a vacuum of approximately one-half inch of water in the

chambers

24 and 40 during operation is satisfactory.

PHOTOCELL CONTROLS For control purposes described hereinafter, a pair of combined light source and

photocell units

60 and 61 and a pair of photocells 62 and 63 are mounted on an adjustable bracket 64 extendingfrom the sewing head 1. The

units

60 and 61 are located adjacent the needle bar 2 and the photocells 62 and 63 are located upstream of the needle 3. The photocells 62 and,63 may, for example, be located about four inches in advance of the needle 3. The photocells 62 and 63 are located so as to receive light from an elongated light source 65 which may, for example, be an infra-red lamp, the light source 65 being located below the belt 8 and the wall 23 and the light from such light source 65 passing through the apertures in the surface 23 and in the belt 8 and to the photocells 62 and 63.

Light'from the combined light source-photocell units .60 and 61 is directed through the transparent lift plate 9 onto the surface of the reflecting tape 11, which may, for example, be of a known type having minute hemispherical reflectors adhesively secured to a tape. The light from the source in the unit 61 is reflected by the tape 11 and received by the photocell in the unit 61. The light from the source in the unit 60 is reflected by the tape and received by the photocell within the unit 60. Such photocells 62 and 63 and combined

sourcephotocell units

60 and 61 are well-known in the art and need not be described in further detail.

The adjustable mounting for the bracket 64 is shown in greater detail in FIG. 5, and as illustrated therein the combined light source-

photocell units

60 and 61 are mounted at the lower end of the bracket 64 which is pivotally mounted at 66 and which is adjustable round the pivot point by means of

adjustable screws

67 and 68. Asdescribed hereinafter, the unit 60 senses the edge of the material being sewn and by adjusting the position thereof with respect to the needle 3, the distance of the stitching in the material being sewn from the edge thereof may be adjusted.

For the purpose of housing the various controls required for operation of the apparatus, the apparatus may be provided with a housing 70 having a control panel 71 for the mounting of most of the manual controls.

STITCH FORMING MECHANISM It is desirable to keep the gap between the adjacent portions of the belts 7 and 8, i.e., the space between the nose bars 31 and 38, to a minimum to facilitate the transfer of material from the belt 8 to the belt 7. Also, commercially available endless belts suitable for use as belts 7 and 8 have a minimum bending radius. Because of the desire to keep such gap to a minimum and the limitation in the minimum bending radius of the belts 7 and 8, the space intermediate the belts 7 and 8 and below the needle 3 is relatively limited. At the present time, there is no commercially available looper mechanism suitable for the stitch forming mechanism 6 and having the size and shape required to fit into the space between the belts 7 and 8 below the needle 3 when the apparatus has the configuration shown in the drawings. Accordingly, it has been necessary to modify a com mercially available looper mechanism to perform the thread looping action when the apparatus of the invention is to be employed to produce a Federal type No. 401 stitch. Thus, while some of the parts in the looper mechanism employed with the sewing apparatus of the invention correspond to parts found in commercially available looper mechanisms, and while the functions and operations of such parts are similar to the functions and operations of the parts in commercially available looper mechanisms, certain of the parts are new in design and some are modified in size and/or shape and certain modifications in the driving mechanisms have been made in order to obtain a looper mechanism which will fit within the space available between the endless belts 7 and 8 in the sewing apparatus of the invention.

With reference to FIGS. 6-11, the modified looper mechanism employed with the sewing apparatus of the invention comprises a drive shaft 72 driven by a belt 73 which, in turn, is driven by a pulley 73a (FIG. 5) in the sewing head 1 and driven by the motor 4. A portion of the drive shaft 72 in the shape of a partial ball 74 is located eccentrically with respect to the axis of the shaft 72 and is encircled by a socket portion at one end of an arm 75, which has a ball joint connection on its opposite end with an arm 76 pivotable about the axis of a shaft 77. The arm 76 is connected to an arm 78 so as to oscillate such arm about the axis of the shaft 77 as indicated by the double-ended arrow 79 (FIG. 6). The end of the arm 78 remote from the axis of the shaft 77 is pivotally connected to one end of a Pitman rod 80, the opposite end of which is pivotally connected to a support 81 for a looper 82. The support 81 is pivotable about the axis of the shaft 83 so that as the drive shaft 72 rotates the looper 82 oscillates as indicated by the double-ended arrow 84 (FIG. 6).

The shaft 83 is mounted on a sleeve 85 (FIGS. 8 and 11) carried by and secured to a rocker shaft 86 which is driven by a collar 87 (FIG. 6) secured thereto and having an arm 88 pivotally connected to a driving member 89 having a portion thereof surrounding an eccentric 98 (FIG. 9) mounted on and driven by the driving shaft 72 and rotatable with respect to the member 89. Thus, as the drive shaft 72 rotates the driving member 89 oscillates as indicated in FIG. 9 between the position shown in solid lines and the position shown in dotted lines, and causes oscillation of the rocker shaft 86 and hence oscillation of the looper 82 in the directions indicated by the double-ended arrow 99 shown in FIG. 8. Accordingly, the looper 82 is caused to oscillate not only in the directions indicated by the doubleended arrow 84 in FIG. 6, but also in the directions indicated by the double-ended arrow 99 in FIG. 8.

The looper mechanism comprises a driving member 90 (FIGS. 6 and 10) a portion of which surrounds an i eccentric 91 (FIG. 7), mounted on and secured to the driving shaft 72, the eccentric 91 being rotatable with respect to the member 90. The driving member 90 is pivotally connected to an arm 92 of a support for a rear needle guard 93 (FIGS. 6, 7 and 110) which is pivotally mounted on the rocker shaft 86. As the drive shaft 72 rotates, the driving member 90 is oscillated, as described hereinbefore for the driving member 89, thereby causing the rear needle guard 93 to oscillate in the directions indicated by the double-ended arrow 97 shown in FIGS. 7 and 10 and between the positions indicated in solid and dotted lines in FIG. 10. A front needle guard 95 (FIGS. 6, 7 and 9) is mounted on and secured to the rocker shaft 86 so as to oscillate therewith and to move in the directions indicated by the double-ended arrow 95a between the positions indicated in solid and dotted lines in FIG. 9.

The looper mechanism also comprises a looper thread take-up mechanism designated generally by the reference numeral 100 and illustrated in FIGS. 6, 7 and 12. As shown in these figures, the thread take-up mechanism comprises a pair of

cams

101 and 102 mounted on and secured to the drive shaft 72'so as to rotate therewith. The looper thread 103 passes over the

cams

101 and 102 and through an eye bracket 104 and from the eye bracket l04the thread 103 passes through a guide tube 105 (FIGS. 6 and 12) to the looper 82 which has an aperture lengthwise thereof through which the thread 103pas ses. In advance of the

cams

101 and 102 the thread 103 is tensioned by a conventional thread tensioning device so that when the looper 82 moves from left to right as viewed in FIG. 6 and tends to produce slack in the thread 103 between the looper 82 and the guide tube 105, such slack is taken up by reason of the rotation of the

cams

101 and 102, the timing of the

cams

101 and 102 with respect to the movement of the looper 82 being such as to so take up the thread slack. As the

cams

101 and 102 rotate, the thread 103 is moved against the bar 106 which increases the length of the path of the thread 103 from the right-hand side of the cam 102 to the left-hand side of the cam 101 as viewed in FIG. 12. I

The functions and movements of the looper 82, the rear needle guard 93, the front needle guard and the thread take-up mechanism are substantially the same as those in a well-known looper mechanism, such as the looper mechanism commercially available from the Singer Manufacturing Company which is described in the Singer Manufacturing Company Manual No. 552. The looper mechanism described provides the Federal stitch type 401 which is described in the hereinbeforementioned publication of the Union Special Machine Company. Briefly, the function of the looper 82 is to provide loops in the thread supplied through the needle 3 when it penetrates the material being sewn and to provide interlocking loop thread at the bottom side of the material being sewn. The functions of the rear needle guard 93 and the front needle guard 95 are to guard the needle 3 while it moves downward to penetrate the material being sewn.

Although the invention has been described in con nection with the use of a chain stitching sewing head 1 and a looper mechanism 6, it will be apparent to those skilled in the art that other sewing heads and other stitch forming mechanisms may be employed in place of the sewing head 1 and the looper mechanism 6. However, in order to permit the stitch forming mechanism to fit into the space between the adjacent portions of the belts 7 and 8 when disposed as shown in the drawings, it usually will be necessary to add new parts and to modify certain of the parts of a conventional stitch forming mechanism in a manner which will be apparent to those skilled in the art from the embodiment illustrated in the drawings and described herein. It will be noted that the looper mechanism described hereinbefore and shown in the drawings differs from the commercially available looper mechanism mentioned hereinbefore in that the looper 82 is modified in shape, the rear needle guard 93 is new in design, the rocker shaft and front and rear needle guards are differently mounted and driven, a thread guide tube 105 and a new housing 12 are added and some shape modifications of other parts are required.

TRANSFER OF MATERIAL FROM BELT TO BELT When the blower 54 has been turned on and a vacuum has been created in the

vacuum chambers

24 and 40, the air flow adjacent to the gap between the adjacent portions of the belts 7 and 8 is as illustrated in FIG. 13 when there is no material to be sewn, such as a garment 110 comprising two

layers

111 and 112, adjacent to such gap. Thus, air flows into the chamber 24 through the belt 8 and the supporting surface therefor as indicated by the arrows 113. Air also flows into the space between the curved leading end portion 9a of the lift plate 9 as indicated by the arrows 114, flows across the anvil 10 into the vacuum chamber 40 and flows into the space at the opposite end 9b of the lift plate 9 as indicated by the arrows 115. At the same time, air flows upwardly around the stitch forming mechanism 6 and into the spaces between the anvil l and the adjacent portions of the belts 7 and 8 as indicated by the arrows 116. However, due to the presence of the lift plate 9, the pressure in the space between the plate 9 and the belt 7 is less than the pressure immediately above the belt 8.

Although the leading edge of the limp garment 110 may be transferred from the belt 8 to the belt 7 across the anvil 10 without the presence of the lift plate 9, it has been found that the garment 110 has a tendency, in the absence of the plate 9, to engage the anvil l0 and be retarded thereby causing the stitching to be uneven. However, when the plate 9 .is employed, it affects the air flow at the anvil 10 so that the leading edge 110a of the garment 110 is lifted across the gap between the adjacent portions of the belts 7 and 8. I

The plate 9 is made of light transparent material so as to permit light from the

units

60 and 61 to pass therethrough and be reflected from the reflecting tape 11, and to return to to the photocell portion of the

units

60 and 61. The plate 9 may, for example, be made of a transparent plastic, and it has a hole 117 therethrough for the passage of the needle 3 therethrough. The edge of the leading end portion 9a of the plate 9 may be approximately two to three inches in advance of the needle 3, and although preferably it is curved as shown to facilitate entry of the leading edge of the garment 110 and to gradually produce the desired air flow, the entire plate 9 may be flat rather than curved at the portion 9a. The edge of the end portion 9b of the plate 9 may be six to eight inches downstream of the needle 3 and the spacing between the lower surface of the plate 9 and the upper surface of the belt 7 may be of the order of one-eighth to three-eighths inches depending upon the thickness of the material to be sewn and its flexibility and depending upon the amount of lift desired.

From FIG. 14 it will be noted that as the leading edge a of the garment 110 approaches the leading end portion 9a of the plate 9, the air flow changes as indicated by the arrows in FIG. 14. Thus, while there still is flow of air into the vacuum chamber 24 through the v garment 110, the belt 8 and the supporting surface for the belt 8, the volume and direction of principal air flow into the space between the leading edge of the plate 9 and the belt 8 is modified as indicated by the arrows 118. At the same time, the velocity of the air flow upwardly between the anvil 10 and the adjacent portions of the belts 7 and 8 increases.

When the leading edge 110a of the garment 110 reaches the gap between the anvil 10 and the belt 8, it is subjected to upward pressure by the air flowing upwardly through such latter gap causing the leading edge portion of the garment 1 10 to lift off the belt 8. As the leading edge of the garment 110 continues to move to the left, as viewed in FIG. 15, it is maintained in slightly spaced relation with respect to the top of the anvil 10 I by virtue of the air flow indicated by the arrows 119,

so that the leading edge portion of the garment 110 is suspended by air as it proceeds across the anvil l0 and until it reaches the belt 7. Thereafter, the air flow is as indicated in FIG. 16 and it will be noted that air flow is maintained between the garment 110 and the anvil 10 as the garment is fed beneath the needle 3, thereby avoiding any substantial contact between the anvil l0 and the garment, except during the time that the needle 3 is passing downwardly therethrough.

GENERAL DESCRIPTION OF OPERATION To operate the apparatus of the invention, the operator turns on the electrical power which, in addition to other functions, energizes the motor 27 and energizes the blower motor 55 which creates a vacuum in the

vacuum chambers

24 and 40. The operator then sets the control for the speed at which the

motors

27 and 34 are to drive the belts 8 and 7 respectively, to a speed which will provide the desired number of stitches per inch in the material to be sewn. For example, if the stitching speed of the sewing head 1 is 3,750 stitches per minute, then to produce ten to twelve stitches per inch in the material to be sewn the linear speed of the belts 7 and 8 should be adjustable from about 5 to 7 inches per second.

The material to be sewn, such as the garment 110 consisting of one or more layers of

material

111 and 1 12, is placed on the moving belt 8 as indicated in FIG. 3. The vacuum within the vacuum chamber 24 causes the air external to the garment 110 topress or clamp the garment 110 against the surface of the belt 8. Although only one garment 110 is shown, such garment l 10 may be secured at its trailing edge 1100 to the leading edge of another garment by tack stitching.

Until the garment 110 reaches a position with its leading edge 110a immediately above the lamp 65, the sewing head 1, the anvil l0 and the stitch forming or looper mechanism 6 are in their most forward positions, i.e., to their right-most positions as viewed in FIGS. 1 and 5.

When the leading edge 1111a of the garment 110 reaches a position over the lamp 65 it cuts off the light directed from the lamp 65 to the photocells 62 and 63. The photocell 63 controls a circuit hereinafter described which causes the motor 4, which drives the sewing head 1, and the driving motor 34 for the belt 7 to be energized when the light from the lamp 65 no longer falls on the photocell 63. The photocell 62 controls a circuit described hereinafter which, when the light from the lamp 65 no longer falls on the photocell 62, energizes the circuit for the positioning motor 20., or other similar device, such as a hydraulic servo valve, causing the sewing head 1, etc. to move from the right to the left as viewed in FIGS. 1 and 5, until a predetermined amount of light is received by the photocell 62 and hence, the needle 3 is positioned with respect to the edge 1111b of the garment 1111 so that the stitching will be produced at the desired distance from the edge 1111b. As mentioned hereinbefore, such distance is adjustable by means of the adjusting screws 67 and 68 (FIG. 5).

When the leading edge 110a of the garment 111) reaches a position immediately beneath the needle 3, the sewing head 1 and the stitch forming mechanism 6 are already in operation and ready to stitch the garment 1111 adjacent the edge 1111b thereof. Also, when the leading edge 110a reaches a position immediately beneath the needle 3, the edge sensing function is transferred from the photocell 62 to the light sourcephotocell unit 60 by reason of the interruption of the light reflected to the

units

60 and 61 from the reflecting tape 11. Also, since the light reflected to the photocell of the unit 61 is interrupted by the leading edge 116a, the functions of the photocell 62 are transferred to the control of the unit 61.

The garment 1111 continues to move in the direction of the arrow 22 (FIGS. 1 and 3) and the sewing head 1 and the stitch forming mechanism 6 cause the

layers

111 and 112 of the garment 1111 to be stitched together along the edge 1111b thereof. When the trailing edge 1111c passes from beneath the needle 3, operation of the sewing head and the stitch forming mechanism 6 continues for a short period of time, for. example, until the trailing edge 1111c has passed approximately 3 inches beyond the anvil 111, and then the sewing head 1 and the belt '7 stop. If the trailing edge 110a is secured to the leading edge of another garment, such continued stitching and movement of the belt 7 will assist in pulling the leading edge of the succeeding garment across the anvil 16. 0f course, if the garment 1111 is followed by another garment by only a short distance, the stitching and movement of the belts 7 and 8 will continue.

ELECTRICAL CQNTROLS The electrical block diagram of FIG. 17 illustrates one combination of controls individually well-known in the art which may be employed for controlling the various functions of the sewing apparatus of the invention described hereinbefore. As illustrated by FIG. 17, alternating current, electrical power, such as three-phase, 50/60-cycle electrical power, is supplied to the apparatus through the line 120. After passing through a circuit breaker 121, the electrical power is supplied to a transformer 122 and to the starter 123 for the motor 55 which operates the blower 54 (FIG. 2). The starter 123 is controlled by an on-off switch 124.

The output of the transformer 122 is connected to the various control circuits through a manually operable switch 125 which may be mounted on the panel 71 (FIG. 2). The output of the transformer 122 is also connected by way of a line 126 to a voltage controller 127, the output of which is connected to a rectifier circuit 128, such as a full-wave bridge rectifier. The direct current output of the rectifier circuit 128 is supplied to the lamp which may provide light predominantly in the infra-red spectrum.

The panel switch is connected through a line 129 to a control 130 which may also be mounted on the panel 71 (FIG. 2). The control 130 is connected to a speed adjuster 131 for the motor 27 which drives the belt 8 and to the speed adjuster 132 for the motor 34 which drives the belt 7. By means of the

adjusters

131 and 132 the

motors

27 and 34 may be adjusted in speed so that the rates of movement of the belts 7 and 8 are substantially the same and by adjusting the control 130, the speeds of the

motors

27 and 34 may be simultaneously adjusted to provide the desired number of stitches per inch in the garment 110. i

A low voltage power supply 133 for the lamps in the units 60'and 61 is connected to the panel switch 125 through the line 129. The supply 133 is connected to the lamps in the

units

60 and 61 through adjustable dimming controls 134 and 135.

The motor 4 which drives the sewing head 1 and the stitch forming mechanism 6 is connected to a controller 136 therefor, the controller 136 being connected to the switch 125 through the line 137'. The controller 136 has a control 138 for control of the speed of the motor 4. Energization of the motor 4 is controlled by a slow release relay 139.

The reversible servo motor 20, which controls the position of the plaste 13 carrying the sewing head 1, etc., is controlled by a conventional controlling circuit 1411 and is, in turn, controlled by a control relay unit 141 connected to the photocells of the

units

60 and 61 and to a pair of

limit switches

142 and 143. The control relay unit 141 may comprise a plurality of relays. The limit switch 142 is operated when the plate 13 reaches its most forward position and the other limit switch 143 is operated when the plate 13 reaches its rear-most position thereby establishing the extreme limits for movement of the plate 13 which, as described hereinbefore, carries the sewing head 1, the anvil 10, the plate 9 and the stitch forming mechanism 6.

The photocell 63 controls a relay 144 so that when the photocell 62'is no longer receiving light from the lamp 65, the relay 144 operates the relay 139 causing the motor 4 to be energized and also energizes the motor 34 through the contacts 145 thereof.

The relay unit 141 is controlled by the photocell 62 so that when the photocell 62 receives light exceeding a level in a predetermined range from the lamp 65, the output of the relay unit 141, after processing in the signal operational amplifier 146, causes the motor 20 to be energized by the controller in a direction which causes the plate 13, and hence, the components carried thereby, to move to the right as viewed in FIG. 5, until the forward limit switch 142 is actuated. However, when the light from the lamp 65 to the photocell 62 is interrupted by the leading edge of the garment. 110, the photocell 62 operates the relay unit 141 so as to cause the motor 20 to reverse and move the plate 13 to the left as viewed in FIG. 5 until light at a level within said predetermined range is again received from the lamp 65 by the photocell 62, and hence, when the needle 3 has reached a predetermined position with respect to the edge 11Gb of the garment 110.

The photocell portions of the

units

60 and 61 jointly control the relay unit 141, so that when the photocell of the unit 61 does not receive light reflected from the tape 11, the relay unit 141 takes over the control of the relay 139 so as to maintain the motor 4 energized as long as the unit 61 does not receive reflected light. Also, the relay unit 141 transfers the edge sensing from the photocell 62 to the photocell of the unit 60. The photocell of the unit 60 then controls the relay unit in a manner similar to the manner in which it was controlled by the photocell 62. Thus, if the photocell of the unit 60 receives light from the tape 11 having a level within a predetermined range, the motor will not be energized, but if the light level is less the motor 20 will be energized in a direction which will move the plate 13 to the left as viewed in FIG. 5. Conversely, if the re-.

flected light level is above said range, the motor 20 will move the plate 13 to the right as viewed in FIG. 5. Accordingly, if the needle 3 is correctly positioned with respect to the edge 11012 of the garment 110 when control of the relay unit 141 is transferred from the photocell 62 to the unit 60, the motor 20 will not be energized, but if the needle 3 is not, the motor 20 will be energized as required until the needle 3 is correctly positioned. Similarly, if the position of the edge 11012 varies, e .g., because it is irregular, non-linear, or not parallel to the direction of movement, then, the motor 20 will be energized as required to cause the stitching to remain within a predetermined distance of the edge 11Gb.

Since control of the relay 141 is taken over by the

units

60 and 61 and the relay 141 is not longer controlled by the photocell 63, the motor 4 and the belt 7 do not stop when the photocell 63 again receives light from the lamp 65 after the passage of the trailing'edge 110C of the garment 110 beyond the lamp 65 because therelay 139 is controlled by the relay 141 rather than the relay 144. When the photocell of the unit 61 again receives light reflected from the tape 11 as a result of the passage of the trailing edge 1100 beyond the needle 3, the relay 141 opens the circuit for the relay 139, but, because the relay 139 is a delayed release relay, the

1 motor 4 which drives the sewing head 1 and the motor 34 which drives the belt 7 will continue to operate for a period of time determined by the release delay time of the relay 139. If, at this time, another garment is between the lamp 65 and the photocell 61, the

motors

4 and 34 will continue to operate, and the sewing of such other garment will take place as described hereinbefore for the garment 110. However, if there is no garment interrupting the light path between the lamp 65 and the photocell 63, the relay 139 will release, stopping the

motors

4 and 34, and the motor 20 will be operated by the photocell 62, as described hereinbefore, to move the plate 13 to its right limit position as viewed in FIG. 5.

Although the control circuits illustrated in FIG. 17 illustrate one embodiment of circuits which may be employed to accomplish the operation described, it will be apparent to those skilled in the art that other known types of control circuits may be used.

While the invention has been described in connection with a preferred embodiment, it will be obvious to those skilled in the art that various modifications can prising a pair of air pervious conveyor belts each having I a first surface for receiving said material and mounted for movement of said first surface thereof in a predetermined direction, said belts being aligned in said direction with a gap therebetween extending, in length, transversely to said direction; first drive means for moving said belts in said direction; vacuum means at the one side of each of said belts opposite from said first surface thereof for drawing air therethrough in the direction from said first surface thereof to the opposite second surface at the other side thereof; needle drive means at said one side of said belts and adjacent said gap; thread forming means at said other side of said belts, adjacent said gap and aligned with said needle drive means; mounting means carrying said needle drive means and said thread forming means and movable transversely of said direction whereby said needle drive means and said thread forming means are jointly movable transversely of said direction and along the length of said gap; reversible second drive means for moving said mounting means transversely of said direction; and control means connected to said second drive means for controlling the position of said mounting means, said control means comprising sensing means for sensing an edge of said material and mounted for movement with said mounting means and means for operating said second drive means under control of the said sensing means so as to maintain said needle drive means in a predetermined positional relation with respect to said edge of said material.

2. Sewing apparatus as set forth in claim 1, further comprising lift plate means extending across and lengthwise of said gap for directing the flow of air through and adjacent said gap so as to lift said material as the edge thereof reaches said gap, said lift plate means having a surface closely adjacent to but spaced from the portions of said belts adjacent to said gap and extending across said gap.

3. Sewing apparatus as set forth in claim 1, wherein said control means is also connected to said needle drive means for initiation of the operation thereof upon sensing of said edge of said material by said sensing means.

4. Sewing apparatus as set forth in claim 1, further comprising a pair of nose bars and wherein each of said belts passes around a nose bar at said gap and thereby define a narrow said gap intermediate the nose bar over which one belt passes and the nose bar over which the other belt passes and wherein at least a portion of said thread forming means extends into said gap and between said nose bars.

5. Sewing apparatus as set forth in claim 4, further comprising a stitching anvil in said gap and intermedi' ate said needle drive means and said thread forming means, said anvil being mounted on said mounting means for movement therewith.

6. Sewing apparatus for stitching sheet material comprising: v i

a pair of air pervious, endless conveyor belts, each mounted to move in a re-entrant path, an upper portion of which is substantially rectilinear to provide generally flat upper surfaces of said belts which are adapted to receive said material, said belts being aligned in the direction of movement of said upper surfaces with a gap between adjacent ends of said surfaces which gap, in length, extends substantially perpendicularly to said direction, and one of said belts being a leading belt and the other of said belts being a trailing belt;

first drive means connected to said belts for moving said belts and moving the upper surface of said leading belt toward said gap andthe upper surface of said trailing belt away from said gap;

vacuum means beneath the rectilinear portions of the paths of said belts to draw air through said belts whereby material may be drawn against said upper surfaces of said belts;

reciprocable mounting means mounted adjacent said gap, said mounting means being reciprocable in the lengthwise direction of said gap;

needle drive means mounted adjacent said gap and on said mounting means and adapted to pass a needle through material passing across said gap from.

one said belt to the other thereof;

light reflecting means mounted from said mounting means and at said gap;

thread forming means mounted adjacent said gap and on said mounting means for receiving thread from said needle and acting thereon;

reversible second drive means for reciprocating said mounting means; light source and photocell means mounted from said mounting means for directing light on said light reflecting means and receiving light reflected therefrom, the path of said light from the light source to said photocell being interceptable by material passing across said gap; and control means connected to said light source and photocell means and to said second drive means for operating said second drive means when said path of said light from said light source is intercepted by an edge of said material so as to maintain said needle drive means in a predetermined position with respect to said last-mentioned edge. 7. Sewing apparatus for stitching sheet material as set forth in claim 6, further comprising lift plate means from said mounting means and extending from over a portion of said trailing belt, across said gap and to a point over a portion of said leading belt adjacent said gap for directing the flow of air through and adjacent said gap so as to lift material as it reaches said gap, said plate means having its lower surface closely adjacent but spaced from the upper surfaces of said belts and extending in a direction lengthwise of said gap, said plate being light transparent at least at the portion thereof in the path of light from said light source.

8. Sewing apparatus for stitching sheet material as set forth in claim 6, further comprising:

lamp means mounted beneath said rectilinear portion of the path of said leading belt and adjacent said gap for directing light through said leading belt adjacent to said gap and along a path which is interceptable by material on said leading belt;

photocell means mounted from said mounting means and above and spaced from said lamp for receiving light from said lamp; and

further control means connected to said photocell means and to said needle drive means and said second drive means for energizing said needle drive means when said path of said light is intercepted by an edge of said material and for operating said second drive means until said needle drive means assumes a predetermined position with respect to said edge.

9. Sewing apparatus for stitching sheet material as set forth in claim 6, wherein said control means connected to said light source and photocell means is also connected to said needle drive means and for energizing said needle drive means when said path of said light from said light source is intercepted by an edge of said material.

10. Sewing apparatus for stitching sheet material comprising:

a pair of air pervious, endless conveyor belts, each mounted to move in a loop-shaped path, an upper portion of which is substantially rectilinear to pro vide substantially plane, substantially horizontal upper surfaces of said belts which are substantially co-planar and which are adapted to receive said material, said belts being aligned in the direction of movement of said upper surfaces with a gap be-- tween adjacent ends of said surfaces which gap, in length, extends substantially perpendicularly to said direction, and one of said belts being a leading belt and the other of said belts being a trailing belt;

variable speed, first drive means connected to said belts for moving said upper surfaces of said belts at substantially the same surface speedand the upper surface of said leading belt toward said gap and the upper surface of said trailing belt away from said gap;

vacuum means including a pair of vacuum chambers, one mounted beneath the rectilinear portion of the path of one of said belts to draw air through said one belt and the other mounted beneath the rectilinear portion of the path of the other of said belts to draw air through said other belt, whereby material may be drawn againstsaid upper surfaces of said belts;

reciprocable mounting means mounted adjacent and below said gap, said mounting means being reciprocable in the lengthwise direction of said gap;

needle drive means mounted above said gap and on said mounting means and adapted to pass a needle through material passing across said gap from one said belt to the other thereof;

a stitch anvil mounted at said gap and on said mounting means for supporting said material as it is stitched and as it passes acrosssaid gap;

light reflecting means mounted on the upper surface of said anvil, the upper surface of said light reflecting means having mirror-like reflecting properties;

thread loop forming means mounted below said gap and on said mounting means for receiving thread from said needle and acting thereon;

reversible second drive means for reciprocating said mounting means;

photocell means mounted from said mounting means and above and spaced from said lamp for receiving light from said lamp;

first control means connected to said photocell means and to said needle drive means and said second drive means for energizing said needle drive means when said path of said light is intercepted by an edge of said material and for operating said second drive means until said needle drive means assumes a predetermined position with respect to said edge;

light source and photocell means mounted from said mounting means for directing light on said light refleeting means and receiving light reflected therefrom, the path of said light from the light source to said photocell being interceptable by material passing across said gap;

second control means connected to said light source lift plate means mounted from said mounting means and extending from over a portion of said trailing belt, across said gap and to a point over a portion of said leading belt adjacent said gap for directing the flow of air through and adjacent said gap so as to lift material as it reaches said gap, said plate means having its lower surface closely adjacent but spaced from the upper surfaces of said belts and the upper surface of said anvil and extending in-a direction lengthwise of said gap for a distance at least equal to the major portion of the dimension of said leading belt in the direction perpendicular to the direction of movement of its upper surface and said plate being light transparent at least at the portion thereof in the path of light from said light source.

Claims

1. Sewing apparatus for stitching sheet material comprising a pair of air pervious conveyor belts each having a first surface for receiving said material and mounted for movement of said first surface thereof in a predetermined direction, said belts being aligned in said direction with a gap therebetween extending, in lEngth, transversely to said direction; first drive means for moving said belts in said direction; vacuum means at the one side of each of said belts opposite from said first surface thereof for drawing air therethrough in the direction from said first surface thereof to the opposite second surface at the other side thereof; needle drive means at said one side of said belts and adjacent said gap; thread forming means at said other side of said belts, adjacent said gap and aligned with said needle drive means; mounting means carrying said needle drive means and said thread forming means and movable transversely of said direction whereby said needle drive means and said thread forming means are jointly movable transversely of said direction and along the length of said gap; reversible second drive means for moving said mounting means transversely of said direction; and control means connected to said second drive means for controlling the position of said mounting means, said control means comprising sensing means for sensing an edge of said material and mounted for movement with said mounting means and means for operating said second drive means under control of the said sensing means so as to maintain said needle drive means in a predetermined positional relation with respect to said edge of said material.

5. Sewing apparatus as set forth in claim 4, further comprising a stitching anvil in said gap and intermediate said needle drive means and said thread forming means, said anvil being mounted on said mounting means for movement therewith.

6. Sewing apparatus for stitching sheet material comprising: a pair of air pervious, endless conveyor belts, each mounted to move in a re-entrant path, an upper portion of which is substantially rectilinear to provide generally flat upper surfaces of said belts which are adapted to receive said material, said belts being aligned in the direction of movement of said upper surfaces with a gap between adjacent ends of said surfaces which gap, in length, extends substantially perpendicularly to said direction, and one of said belts being a leading belt and the other of said belts being a trailing belt; first drive means connected to said belts for moving said belts and moving the upper surface of said leading belt toward said gap and the upper surface of said trailing belt away from said gap; vacuum means beneath the rectilinear portions of the paths of said belts to draw air through said belts whereby material may be drawn against said upper surfaces of said belts; reciprocable mounting means mounted adjacent said gap, said mounting means being reciprocable in the lengthwise direction of said gap; needle drive means mounted adjacent said gap and on said mounting means and adapted to pass a needle through material passing across said gap from one said belt to the other thereof; light reflecting means mounted from said mounting means and at said gap; thread forming means mounted adjacenT said gap and on said mounting means for receiving thread from said needle and acting thereon; reversible second drive means for reciprocating said mounting means; light source and photocell means mounted from said mounting means for directing light on said light reflecting means and receiving light reflected therefrom, the path of said light from the light source to said photocell being interceptable by material passing across said gap; and control means connected to said light source and photocell means and to said second drive means for operating said second drive means when said path of said light from said light source is intercepted by an edge of said material so as to maintain said needle drive means in a predetermined position with respect to said last-mentioned edge.

7. Sewing apparatus for stitching sheet material as set forth in claim 6, further comprising lift plate means from said mounting means and extending from over a portion of said trailing belt, across said gap and to a point over a portion of said leading belt adjacent said gap for directing the flow of air through and adjacent said gap so as to lift material as it reaches said gap, said plate means having its lower surface closely adjacent but spaced from the upper surfaces of said belts and extending in a direction lengthwise of said gap, said plate being light transparent at least at the portion thereof in the path of light from said light source.

8. Sewing apparatus for stitching sheet material as set forth in claim 6, further comprising: lamp means mounted beneath said rectilinear portion of the path of said leading belt and adjacent said gap for directing light through said leading belt adjacent to said gap and along a path which is interceptable by material on said leading belt; photocell means mounted from said mounting means and above and spaced from said lamp for receiving light from said lamp; and further control means connected to said photocell means and to said needle drive means and said second drive means for energizing said needle drive means when said path of said light is intercepted by an edge of said material and for operating said second drive means until said needle drive means assumes a predetermined position with respect to said edge.

10. Sewing apparatus for stitching sheet material comprising: a pair of air pervious, endless conveyor belts, each mounted to move in a loop-shaped path, an upper portion of which is substantially rectilinear to provide substantially plane, substantially horizontal upper surfaces of said belts which are substantially co-planar and which are adapted to receive said material, said belts being aligned in the direction of movement of said upper surfaces with a gap between adjacent ends of said surfaces which gap, in length, extends substantially perpendicularly to said direction, and one of said belts being a leading belt and the other of said belts being a trailing belt; variable speed, first drive means connected to said belts for moving said upper surfaces of said belts at substantially the same surface speed and the upper surface of said leading belt toward said gap and the upper surface of said trailing belt away from said gap; vacuum means including a pair of vacuum chambers, one mounted beneath the rectilinear portion of the path of one of said belts to draw air through said one belt and the other mounted beneath the rectilinear portion of the path of the other of said belts to draw air through said other belt, whereby material may be drawn against said upper surfaces of said belts; reciprocable mounting means mounted adjacent and below said gap, said mounting meAns being reciprocable in the lengthwise direction of said gap; needle drive means mounted above said gap and on said mounting means and adapted to pass a needle through material passing across said gap from one said belt to the other thereof; a stitch anvil mounted at said gap and on said mounting means for supporting said material as it is stitched and as it passes across said gap; light reflecting means mounted on the upper surface of said anvil, the upper surface of said light reflecting means having mirror-like reflecting properties; thread loop forming means mounted below said gap and on said mounting means for receiving thread from said needle and acting thereon; reversible second drive means for reciprocating said mounting means; lamp means mounted beneath said rectilinear portion of the path of said leading belt and adjacent said gap for directing light through said leading belt adjacent to said gap and along a path which is interceptable by material on said leading belt; photocell means mounted from said mounting means and above and spaced from said lamp for receiving light from said lamp; first control means connected to said photocell means and to said needle drive means and said second drive means for energizing said needle drive means when said path of said light is intercepted by an edge of said material and for operating said second drive means until said needle drive means assumes a predetermined position with respect to said edge; light source and photocell means mounted from said mounting means for directing light on said light reflecting means and receiving light reflected therefrom, the path of said light from the light source to said photocell being interceptable by material passing across said gap; second control means connected to said light source and photocell means and to said needle drive means and said second drive means for energizing said needle drive means when said path of said light from said light source is intercepted by an edge of said material and for operating said second drive means so as to maintain said needle drive means in a predetermined position with respect to said last-mentioned edge; and lift plate means mounted from said mounting means and extending from over a portion of said trailing belt, across said gap and to a point over a portion of said leading belt adjacent said gap for directing the flow of air through and adjacent said gap so as to lift material as it reaches said gap, said plate means having its lower surface closely adjacent but spaced from the upper surfaces of said belts and the upper surface of said anvil and extending in a direction lengthwise of said gap for a distance at least equal to the major portion of the dimension of said leading belt in the direction perpendicular to the direction of movement of its upper surface and said plate being light transparent at least at the portion thereof in the path of light from said light source.