US3273523A

US3273523A - Buttonhole-stitching machine and thread-severing means therefor

Info

Publication number: US3273523A
Application number: US431319A
Authority: US
Inventors: Pudelko Hermann
Original assignee: Duerkoppwerke GmbH
Current assignee: Duerkoppwerke GmbH
Priority date: 1964-02-10
Filing date: 1965-02-09
Publication date: 1966-09-20
Anticipated expiration: 1983-09-20
Also published as: NL6501265A; BE659516A; GB1061824A

Description

H. PUDELKO 3,273,523 BUTTONHOLEFSTITCHING MACHINE AND THREAD-SEVERING MEANS THEREFOR 7 Sheets-Sheet 1 Sept. 20, 1966 Filed Feb. 9, 1965 INVENTORZ Hermann Pude/ka A ttorn Y Sept. 20, 1966 H. PUDELKO 3,273,523

BUTTONHOLE-STITCHING MACHINE AND THREAD-SEVERING MEANS THEREFOR Filed Feb. 9, 1965 7 Sheets-Sheet 2 INVENTOR. Hermann Puc/elko {4 GM Attorney Sept. 20, 1966 H. PUDELKO BUTTONHOLE-STITCHING MACHINE AND THREAD-SEVERING MEANS THEREFOR '7 Sheets-Sheet 4 Filed Feb. 9. 1965 INVENTOR. Hermann Pude/ka Attorney H. PUDELKO BUTTONHOLESTITCHING MACHINE AND THREAD-SEVERING MEANS THEREFOR Sept. 20, 1966 7 Sheets-Sheet 5 Filed Feb. 9, 1965 INVENTOR. Hermann Puc/e/ko Se t. 20, 1966 H. PUDELKO BUTTONHOLESTITCHING MACHINE AND THREAD-SEVERING MEANS THEREFOR '7 Sheets-Sheet 6 Filed Feb. 9. 1965 INVENTOR; Hermann Pudelko Sept. 20, 1966 HY PUDELKO BUTTONHOLE-STITCHING MACHINE AND THREAD-SEVERING MEANS THEREFOR 7 Sheets-Sheet 7 Filed Feb. 9, 1965 INVENTOR. Hermann Puclelko Atiomey United States Patent M 3 27 3 523 nUT'roNHorE-srrrcrrhyo MAQHHNE AND THREAD-SEVERING MEANS THEREFOR Hermann Pudelko, Bielefeld, Germany, assignor to Durkoppwerlre Aktiengesellschaft, Bielefeld, Germany, a corporation of Germany Filed Feb. 9, 1965, Ser. No. 431,319 Claims priority, application Germany, Feb. 10, 1964, 1) 43,575 17 Claims. (Cl. Ill-65) This application is a continuation-in-part of my copending application Ser. No. 328,938, filed December 9,

1963, and entitled Buttonhole-Sewing Machine.

In my commonly assigned copending application identified above, there is disclosed a buttonhole-stitching machine in which the stitch forming means (including a generally vertically reciprocable needle, usually capable of forming a zig-zag or buttonhole stitch, and a turret on the fabric carrying table) are rotatable through an angle of 180 to form the buttonhole eye. A rotatable turret of this character is also disclosed in US. Patent No. 1,787,928 and 1,877,159. In the aforementioned application, there is disclosed a stitch-forming device which is additionally provided with means for feeding an underthread and a gimp or stay cord from below to the stitching location. The stitch forming means of this arrangement includes means for releasably retaining the end of the severed underthread and, preferably, also that of the stay cord, in a position relative to the usual throat plate in which it will be positively entrained by the needle or the mechanism cooperating therewith during the first stitch of the next sewing stitch. Thus the throat plate is provided with a slot for the underthread and a channel for the gimp or stay cord both terminating at the sewing opening of the blade which can be mounted upon a fabric carrying table; the slot has an entrance end so dimensioned as to be wide enough to admit the underthread but sufliciently restricted to block the stay cord when the turret is rotated back into its starting position. Moreover, the underthread receiving slot has a slit-shaped outlet which merges with the inlet of the cord receiving channel, a resilient clamping element being so disposed at the outlet of the slot that one portion of this element cooperates with an edge of the slit to engage the underthread whereas another portion of said element separates the slot from the channel to prevent the entry of the underthread into the channel while also applying some friction upon the stay cord.

The present invention relates to buttonhole-stitching machine of this character and it will be understood that hereafter, when reference is made to the stitch forming means, it is intended to include arrangements in which the sewing needle and mechanism cooperating therewith are disposed more or less eccentrically about an upright axis, i.e. the axis of the turret, and are swingable about this axis through an angle of substantially 180 to form the eye of the buttonhole; the longitudinal edges thereof are stitched upon a substantially linearly reciprocating movement of the fabric carrying table which is displaceable relatively to the stitch forming means. Thus the stitch forming means of the copending application or patents identified above may be employed.

While it is known to provide buttonhole-sewing machines of this general character with thread-severing devices for cutting the underthread and the gimp upon formation of the buttonhole in the fabric, it has been found that conventional arrangements frequently result in interference between the severing device and the stitch forming mechanism or the movable fabric carrying table or turret. In many cases, therefore, it is necessary to resort to a severing of the thread by a manual operation,

3,273,523- Patented Sept. 20, 1966 which interferes with the high speed production of buttonholes in an automatic sewing machine or the like. Moreover, extreme care must be taken in adjusting the conventional systems to avoid errors in timing with respect to the thread-severing arrangement and the buttonhole-stitching arrangement. The importance of such timing errors increases as the rate of operation of the machine increases so that, for the most part, conventional severing devices have been unsuitable for high speed automatic buttonhole stitching machines.

It is the principal object of the present invention, therefore, to obviate the aforedescribed disadvantages by providing, in an automatic buttonhole-stitching machine of the character described, a threadsevering device which cannot interfere with the, buttonhole stitching operation and buttonhole-stitching means which will not interfere with the operation of the thread-severing device.

A more specific object of my invention is to provide an improved thread-severing means for a buttonholestitching machine of the type described and claimed in the above-identified copending application.

Yet another object of the instant invention is to provide a relatively simple and foolproof mechanism for operating a thread-severing device of an automatic buttonhole-stitching machine.

The above and other objects, which will become apparent hereinafter, are attained in accordance with the present invention by providing a thread-severing means including cooperating blade means mounted upon the substantially linearly reciprocating table of the buttonhole-stitching machine, the thread-severing means including actuating means manually or automatically operable (e.g. via a pedal and/or a servomechanism) in conjunction with a lock-out mechanism cooperating with the actuating means for preventing the functioning of the blade means during the reciprocating movement of the table but permitting such operation upon return of the table to a position in which thread severing is to be effected. The lockout mechanism, moreover, cooperates with an actuating member of the drive means of the apparatus to prevent the operation thereof and displacement of the table during the thread-severing step.

More particularly, an automatic buttonhole-stitching machine according to the present invention can comprise the usual support means forming a housing or base bearing a generally horizontal sewing-machine arm cantilevered above the housing, the support means carrying the angularly displaceable and eccentric stitch-forming means are previously described; the stitch-forming means, which is described to swing through an angle of substantially about an upright axis, cooperates with a substantially linearly displaceable fabric carrying table designed to position a fabric at a stitching location. The table is displaceable from a starting position at the commencement of a buttonhole-stitching operation with reciprocating movement during the formation of the longitudinal portions of the buttonhole, the swinging movement of the stitching-forming means producing the buttonhole eye in the usual manner. The table can be carn operated and provided with a main clamping means adaped to hold the fabric against the table during the reciprocating movement thereof and to release the fabric upon conclusion of this reciprocating movement and termination of the buttonhole-stitching operation; clutch operated means or the like can be provided in the conventional manner for displacing the table upon the shifting of an actuating member by an operator. The invention resides, at least in part, in the combination with a machine of this type of a thread-severing means on the table and the housing engageable with the underthread and stay cord upon termination of the buttonhole-stitching operation in the aforementioned position of the table; this thread-severing means includes cooperating blade means shiftably mounted on the table and actuating means carried by the housing for activating the blade means. A lockout mechanism is also provided on this housing for immobilizing the actuating means during movement of the table and preventing or shifting of the actuating member during the severing operation.

According to a more specific feature of this invention, the machine is also provided with an auxiliary clamping means operable independently of the main clamping means for holding the fabric in place at least during the severing of the underthread/gimp by the blade means, the lookout mechanism including means for releasing the auxiliary clamping means for the fabric upon conclusion of the severing step and prior to a subsequent reciprocating movement of the table to form another buttonhole.

Still another feature of the present invention resides in the construction of the blade means, the actuating and the lockout mechanism. Thus the blade means can include a slide shiftably mounted toward and away from the stitching location and carrying a first blade member, while a second blade member is swingably mounted on the slide and forms a scissor with the first blade member; adjustable stop means are provided on the table for limiting displacement of the slide toward this location, while firs-t and second levers having a common fulcrum are respectively engageable with the slide and the second blade member and form a lost motion linkage with one another. The actuating means can then include an operating member shiftable on the housing and co-operating with these levers at least in the said position of the table for displacing the second lever and thereby entraining the first lever therewith; a generally horizontally and angularly oscillatable shaft is journaled in the housing and is operatively connected with this latter member for displacing same to shift the levers, manual or servomeans being provided for rotating the shaft from its rest position in a sense effecting displacement of the blade members.

The mechanism can then include an arm carried by the shaft and displaceable together therewith but cooperating with a second vertically displaceable slide member on the housing. A control lever is fulcrumed on the housing and is engageable with the slide member for selectively permitting and preventing its movement, the control lever cooperating with an abutment means provided on the table and displaceable into the path of the control lever to prevent its displacement with the slide member during reciprocating movement of the table; the abutment means is withdrawn from the path of the control lever upon return of the table to its position in which severing of the underthread and gimp is to be elfected.

The oscillating clamping means preferably includes a rod pivotally mounted on the table and provided with a fabric-engaging clamping shoe, a third lever being swingable on this table coaxially with the rod and being coupled therewith via a torsion spring means resiliently urging the rod and the shoe against the fabric upon rotation of this third lever from its rest position into an operating position. The lockout mechanism can then include a latching member swingably mounted on the table and engageable with this third lever for releasably retaining it in its operating position; the control lever is engageable with the latching member for releasing this third lever upon displacement of the slide member by the arm carried by the shaft. The auxiliary clamping means can be provided with a further spring means tending to lift it from the fabric upon such unlatching.

The above and other objects, features and advantages of the present invention will become more readily apparent from the following description, reference being made to the accompanying drawing in which:

FIG. 1 is an overall side-elevational view of a buttonhole-stitching machine provided with an automatic threadsevering device according to the invention;

FIG. 2 is a plan view of the machine table with the sewing-machine arm removed;

FIG. 3 is a plan view, partially broken away, of the buttonhole-stitching portion of the machine drawn to an enlarged scale, the table plates being removed;

FIG. 4 is a partial plan view, drawn to a scale greater than that of FIG. 2 but less than that of FIG. 3 showing the severing device in its rest position;

FIG. 5 is a view similar to FIG. 4 showing the severing device in its cutting position;

FIG. 6 is another view similar to that of FIGS. 4 and 5 showing the cutting device in another operative position;

FIG. 7 is a fragmentary elevational view of the control elements of the severing device;

FIG. 8 is a plan view of a detail of this device drawn to an enlarged scale;

FIG. 9 is a side-elevational view, partly in section, of the detail shown in FIG. 8;

FIG. 10 is a fragmentary plan view of the control unit, illustrating another portion thereof;

FIG. 11 is a fragmentary view taken generally in the direction of the arrow XI in FIG. 10;

FIG. 12 is a fragmentary view drawn to the scale of FIG. 10 and showing a detail thereof in another operative position;

FIG. 13 is a cross-sectional detail view of the portion XIII of FIG. 10;

FIG. 14 is a side elevational view, partly in diagrammatic form, illustrating a servomechanism for controlling a thread-severing device according to the invention;

FIG. 15 is a fragmentary sectional view of a detail of the device of FIG. 14;

FIG. 16 is a circuit diagram of the servomechanism for the device of the system of FIGS. 14 and 15;

FIG. 17 is a plan view of a clamping arrangement for the thread-severing device;

FIG. 18 is a cross-sectional view taken along the line XVIII-XVIII of FIG. 17; and

FIG. 19 is a partial plan view of a detail of the system of FIGS. 17 and 18.

General description of the bz zl'zonhole-stitching apparatus As illustrated in FIGS. 13, the buttonhole-sti tching machine of the present invention comprises a base or housing, generally designated 1, upon which the upper portion 2 of the support means is mounted and which contains the control and severing mechanism for the buttonholestitching and severing units. The housing 1 is, in turn, mounted upon the usual foundation plate, not illustrated. The upper portion of the machine 2 is swingable about the horizontal axis A on the base 1, the latter being provided with control housing 3 whose elements will be described in greater detail hereinbelow. The upper portion of the machine comprises this housing 3, the usual, generally horizontal sewing machine arm 4 and a downwardly and forwardly extending arm 5 shown in broken lines in FIG. 1 and extending into the base 1. The stitch forming mechanism is partly mounted in the sewing machine arm 4 and partly in the downwardly extending arm 5. The stitch forming elements can include a vertically reciprocable sewing machine needle 6 and a gripper and thread feed arrangement 6 mounted in the downwardly extending arm 5. The stitch forming unit is eccentric and rotatable about the vertical axis Y within the arms 4 and 5 together with the turnable as described in my abovementioned application to form the eye of the buttonhole. The support means, i.e. the arm 5, is further provided with a fabric carrying table 7 substantially linearly displaceable in the direction of arrow B forwardly and rearwardly under the control of a main cam disk 8 (FIG. 2) controlled by the drive means in housing 3. The movement of the fabric carrying table 7 is dimensioned to conform to the maximum buttonhole length and the actual length of the but-tonhole sewn by the stitch forming unit 6, 6' is determined by actuating the stitch forming unit earlier or later in accordance with the desired length via the usual cam arrangement.

A pair of plates 9 and 10 (FIG. 2) are mounted upon the fabric carrying table 7 and are provided with respective

fabric clamping members

11 and 12 whose upper surfaces are toothed or roughened for positive entrainment of the fabric. The clamping

members

11 and 12 cooperate, respectively, with the clamping shoes 13 and 14 (FIGS. 1-3) whose undersurfaces engageable with the fabric, may be similarly roughened or toothed. The shoes 13 and 14 (FIG. 3) hold the fabric against the

plates

11 and 12 just laterally of the stitching area and are swingably carried by the

arms

15 and 16, respectively, which are, in turn, pivotally mounted upon the table 7.

Thread-severing means For severing the lower thread (underthread) U and the gimp or stay cord G (FIGS. 3-6), a thread-severing device is provided which, at least during part of the operating cycle, cooperates with an auxiliary clamping means generally designated 17. The severing device comprises a nonswingable first blade member 18 and a swingable second blade member 19 (FIG. 2) disposed in the region of the clamping

plates

11 and 12. These blades are preferably positioned proximal to the region of one end of the buttonhole-stitching area and serve to sever the lower thread U and the gimp G close to the finished buttonhole H. The fixed blade 18 is formed integrally with or is replaceably mounted on a slide 20 (FIGS. 2 and 46) which is slidably mounted in a guide slot 21 (FIGS. 5 and 6) permitting displacement of the slide in the direction of arrow B (FIG. 1) on the table 7. The movable blade 19 is swingably mounted on the slide 20 via a pin 22 (FIGS. 1, 2 and 46). Thus both

plates

18 and 19 cooperate to form a scissor which, in its rest position, is held in an open condition (FIG. 4). The actuation of the

scissors

18, 19 is only possible when the unit has terminated the stitching of a buttonhole, the

stitch forming elements

6 and 6 being then in their assigned end positions.

Blade actuating means The thread-severing control mechanism comprises an angularly oscillatable shaft 23, journaled in

bearings

24 and 25 in the housing 1 (FIGS. 1, 2, l0-12), normally held by a helical torsion spring 69 (FIGS. 1 and 14) in the rest position illustrated in FIG. 10, i.e. in an extreme counterclockwise position. The shaft 23 carries an actuating lever 26 (FIGS. 10-12) whose split collar is fixed to the shaft 23 via a clamping screw 27. An arm 26" at the lever 26 projects laterally of the housing 1 and is connected via a tension spring 28 and a chain 30 with a pedal 29 (FIG. 14). The actuating lever 26 is further provided with an abutment formation 26' (FIGS. 10 and 12) which limits the working stroke of the lever 26 by engagement with a stop 31 constituted by a formation upon the housing 1. The extreme counterclockwise position of the shaft 23 and the lever 26 is determined by an adjusting screw 32 (FIGS. 10 and 12) carried by the lever 26 and engageable with the surface 31 of the housing.

At its other extremity, the shaft 23 carries a lever 33 rigidly fixed to the shaft beyond the bearing 24 via a fastening screw 34 (FIG. 11), the lever 33 having its extremity remote from the shaft 23 in engagement with a further lever like member 35 (FIGS. 10 and 11) via a pivot 36. The lever 35 is, in turn, swingably and linearly shiftable via its slot 35' upon the pivot 37. Another leverlike member 38 is entrained by lever 35 and has one extremity pivotally fixed thereto via a screw 39. The lever 38 is also provided with a longitudinally extending slot 38 generally registering with the slot 35 although the slot 38 is wider than slot 35' which slidingly engages the shank 37 of pin 37. The slot 38 thus receives the pin 37 with play. At its free extremity, the lever 38 is resiliently held against the lever 35 by a spring 40 (FIG. 13). To this end, the lever 35 is provided with a guide piece 41 at its free extremity, screws 42 holding the guide piece 41 to the lever 35 and partially overlying the lever 38 as best seen in FIG. 11. The compression spring 40 surrounds a guide pin 43 in member 41, the pin being slidable with clearance in a bore 44 of lever 38 while being fixed to the guide member 41. Thus the lever 38 is swingable about the pivot 39 relative to the lever 35 through the limits determined by the pin 37 and the play of the slot 38 against the spring 40.

Along its upper edge, the lever 35 is provided with a camming formation 45 (FIG. 10) while the lever 38 likewise has its upper edge provided, close to its free extremity, with a formation 46. Formation 46 is constituted as a roller journaled upon a pin 46' of the lever 38 (FIG. 11).

Referring now to FIGS. 4-7, it will be apparent that a lever 47, swingable upon a fulcrum 48 in the form of an axle, is receivable between the formations 45 and 46 while being carried by the plate 7. Upon actuation of the lever 26 via the pedal 29, the rotation of shaft 23 effects a counterclockwise swing of the lever 33 and a displacement of the

levers

35 and 38 to the right. The formations 45 and 46 swing to the right (in the counterclockwise sense) as seen in FIG. 10 and entrain the lever 47 in this sense. The axle 48 passes through a bore of a bearing portion 49 (FIGS. 4-6 and 8) which is fastened to the material carrying table 7 by means of screws 51). On its upper end, the axle 48 carries an arm 51 fixed thereto whose free extremity is formed with an offset or bent portion carrying a pin 52 (FIG. 7). Below the arm 51, the axle 48 carries a further lever 53 rotatable relatively thereto whose free extremity is, in turn, provided with an up standing pin 54;

arms

53 and 51 constitute the first and second levers operating the blade means 18 and 19.

On its lower extremity, the axle is provided with the lever 47 extending between the formations 45 and 46 as illustrated in FIGS. 3 and 7. The lever 47 and the axle 48 rotate relative to the bearing 49 and its shoulder 49 against the force of a torsion spring 55 whose extremities respectively engage the hub 47' and the boss or shoulder 49'. The spring 55 thus constitutes a restoring means for returning the actuating levers 51 and 5 3 to their rest position upon each operation of the severing means.

When the lever 47 (FIGS. 4-7) is swung in the aforedescribed manner in the clockwise sense, as illustrated in FIG. 5, the axle 48 rigid therewith and its arm 51 are pivoted in the same direction. The lever 53, which is freely swingable upon axle 48 and forms a lost motion linkage with lever 51, is thus entrained by the compression spring 58 in a resilient manner (FIGS. 5 and 6). Both levers 51 and 53 thus tend initially to rotate together with the axle 48 to shift, via the pin 54 and the formation 52, the slide 20 in its guide 21 toward the buttonhole and the stitch forming mechanism 6, 6', i.e. in the direction indicate-d by the arrow D. The stroke of the slide 20 in this direction is limited by an adjustable stop means constituted by a stop projection 60 (FIG. 8) on the bearing sleeve 49 and an adjustable pin 61 carried by the lever 53. As will be apparent from FIGS. 8 and 9, the pin 61 is eccentrically mounted upon an adjusting disk 62' whose head 62 is aligned with an aperture 62" in the plate 9 so as to permit insertion of a screwdriver into the slot 64 for rotation of the disk 62' via this head 62. An opening 53' in lever 53 clears the projecting eccentric pin 61. The eccentric disk 62 is provided with a plurality of an-gularly spaced positions and indexing means for yieldably retaining the disk in these positions. The indexing means can include a multiplicity of angularly spaced spheroidal recesses 63 formed in the wall of the bore 53" housing the disk 62. A pair of diametrically opposite balls 63 are resiliently urged into these recesses by a compression spring 63". When the disk 62' is forcibly rotated, therefore, the balls 63 are cammed inwardly until they snap again into another pair of indexing recesses. The angular position of adjustment of the head 62, the disk 62 and its eccentric pin 61 can be seen from a scale 65 (FIG. 2) surrounding the aperture 62" and through which the head 62 and its slot 64 can be seen. The slot serves .an indicator cooperating with the scale 65 and thus can be seen through the aperture 62". The scale thus not only reveals the position of the eccentric pin 61 but also represents the stroke of the slide 20 controlled thereby. The angular displacement of the disk 62' is limited by a pair of stops 66 with which a pin 67, fixed to and extending trans versely from the head 62, as best seen in FIGS. 6 and 8, cooperates. The stop pins 66 are provided on the lever 53.

As the tension spring 58 entrains the lever 53 with the lever 51 upon rotation of axle 48 only until further movement of arm 53 and/ or the slide 20 is blocked, continued rotation of the axle 48 will bring the eccentric pin 61 to bear upon the formation 60 and immobilize the lever 53, thereby holding the slide 20 in its extreme forward position; this position, selected by setting the disk 62, substantially coincides with the terminus of the buttonhole. Further rotation of the axle 48 elongates the spring 8 while holding the lever 53 against the stop formation 60, whereas lever 51 continues to swing in the clockwise sense (-FIG. 6) to pivot the blade 19 about its fulcrum 22 in the counter-clockwise sense. The

blades

18 and 19 thus cooperate only at the end of the stroke of the slide 20 to sever the lower or underthread U and the gimp or stay cord G.

Upon conclusion of this thread-severing operation, the angularly oscillatable shaft 23, the coil spring 69, which engages the adjusting collar 68, returns the shift 23 to its ineffective position (FIG. provided the pedal 29 has been released. The return of the slide is effected by the abutment formations 45 and 46 which return the lever 47 to its inoperative position (FIG. 4) and thereby swing the

levers

51 and 53 in the counterclockwise sense.

Auxiliary clamping, means As previously noted, the thread-severing device is only operable when the sewing machine is in its rest position, i.e. upon conclusion of a buttonhole switching operation. [In this position, the fabric is held by an auxiliary clamping device generally designated 17 which is operable even after the

clamping plates

13 and 14 have ceased to positively engage the fabric. This auxiliary clam-ping device 17 is rendered effective upon the commencement of the stroke B of the fabric-carrying table 7 which cooperates with an abutment 70 carried by the housing 1 and selectively shiftable in the direction of arrow B while being lockable in any selected position. The auxiliary clamping rod 7&1 of L-shaped configuration has its leg received within the enlarged extremity 72 of a shaft 72 (FIGS. 17 and 18), this shaft being journaled in a block 73 on the fabric carrying table 7; the journal block 73 is secured to this table 7 by a pair of screws 74 (FIG. 17). Upon its free extremity remote from the shaft 72, the arm 71 carries a sleeve 75 (FIGS. 2, 3 and 17) provided with a bayonet coupling 75' cooperating with a pin 71" of the rod 71. The bayonet coupling 75 between the rod 71 and the sleeve 75 permits a swinging movement of the sleeve 75 through an angle of approximately 90. The sleeve 75 carries a clamping shoe 77 which is pivotally secured to a connecting bar 76 at 77' (FIG. 1), the rod 76 projecting radially from and being rigidly fixed to the sleeve 75. The underside of the clamping shoe 77 is toothed, milled or otherwise roughened to insure positive engagement with the fabric in cooperation with a similar-ly roughened surface 78 (FIGS. 4-6) of a lower clamping plate carried by member 10.

Upon is reduced-diameter end 72", the shaft 72 carries a connecting bushing or sleeve 79 having an annular flange 79. A lever 82 is journaled uponthe bushing 79 and is rotatable thereon against the force of a helical torsion spring 84 which is wound upon relative displacement of the bushing 79 and the lever 82 and tends to restore them to their normal relative positions. A retaining nut 80 fixes the bushing 79 to the shaft 72 and is threaded onto the extremity 72" thereof. The spring 84 surrounds a hub 81 of the lever 82 and has one extremity 84' anchored thereto while the other extremity 84" of the spring is anchored to the bushing 79. As indicated in FIGS. 17 and 19, the end 8 1 of the spring can be received in any one of a plurality of angularly spaced notches 83 former around the periphery of a flange 31 of the hub to enable adjustment of the torque applied by the torsion spring means 84 to the lever 82. The flange 79 of the bushing 79 is, moreover, provided with a pin 85 serving as a stop for the lever 82.

Upon its free extremity, the lever 32 is provided With a further pin 86 adapted to engage the further abutment means or stop 79 (FIG. 1) carried by the housing 1. A square cross section stud 37 projecting from the free extremity of lever 82 in a direction opposite pin 86 (FIG. 18) cooperates with a spring loaded latch member or lever 83 adapted to hold the arm 71 in its rest position as will become apparent hereinafter. The clamping force applied by the shoe 77 to the fabric is adjusted by tightening the spring 84, for which purpose the notches 83 are provided.

Lockout mechanism To prevent operation of the thread-severing device during the buttonhole-stitching process, the fabric carrying table 7 can be provided, according to the invention, with an abutment 89 (FIG. 1) adjustable in the direction of arrow B via the locking screws 99. Upon activation of the machine at the commencement of a stitching operation, the actuating member 91 of the drive means can be manually or automatically shifted to move the fabric carrying table 7, via the drive means, into position relative to the stitch forming means 6, 6'. This rapid movement of the table 7 brings the abutment 89 into the path of a double arm control lever 92 fulcrumed upon a pin 93 of the base 1. Upon the rear side of this lever 92, there is provided an adjustable camming or abutment member 94 which is held in place upon the double arm lever 92 by a screw 95 passing through the adjusting slot 96; screw 95 and slot 96 constitute a means permitting relative adjustment of the contacting portion 94 and the lever 92. The upper edge of this oamming portion 94 is engageable with the lower edge of abutment 89 to block clockwise rotation of the lever 92 as soon as the table 7 commences its forward stroke (to the right in FIG. 1) upon actuation of the buttonhole-stitching mechanism. The forward extremity of the lever 92 is provided with a cutout 97 forming a bifurcation between the arms of which is received a pin 98 carried by a vertically movable slide member 99. The slide 99 is shiftable with respect to a guide means constituted by a pair of screws 192 (FIGS. 1, 10 and 12) passing through respective longitudinal slots in the slide 99. The slide is shiftable relatively to the guide blocks 191 carried by the screws 192 and a cover plate 193 overlying the slide, the blocks 101 preventing lateral shifting of the slide (FIGS. 10 and 12). The slide 99 is provided with a recess 1% at its lower end (FIGS. 1 and 12) adapted to receive the head 195' of an arm 195 mounted upon a shaft 23. When the slide 99 is immobilized, the arm 195 prevents rotation of the oscillatable shaft 23.

As has been pointed out earlier, .it is not only essential that the severing mechanism be immobilized during the stitch forming operation, but it is also necessary to insure that the stitching device will be inactive during the operation of the severing device to prevent movement of the thread during the severing operation. For this purpose, the slide 99 acts, via its upper extremity, upon an arcuate spring-loaded retaining member 196 fulcrumed at 197 to the table 7 and cooperatingwith a spring 198 whose two :arms respectively urge the

levers

88 and 106 downwardly. The retaining member, during the downward movement of the slide 99 is swung in the clockwise sense under the torque applied by spring 108 about the fulcrum 107; this downward movement permits the hooked free extremity 106' (FIGS. 1, 2 and 17) to gage a connecting rod 109 by means of which the movement of the actuating lever 91 is transmitted to the control housing 3. Thus actuation of the lever 91 is prevented as long .as the thread cutting mechanism is in operation.

Drive means The machine can be provided with a conventional clutch-controlled drive mechanism or any other system with which the connected rod 189 can cooperate to place the table 7 and the

stitch forming means

6 and 6 in operation. This mechanism can advantageously be of the type disclosed in my copending application Ser. No. 328,938 filed December 9, 1963 and may include a main drive shaft 110 carrying the driven pulley 111 of a belt drive whose belt 112 is entrained by the drive pulley of a motor not shown. The pulley 111 is constantly driven during all periods of machine operation although it is not coupled With the buttonhole-stitching mechanism until the lever 91 is shifted. The drive shaft 110 is provided with a worm 113 which, upon disengagement of the clutch 113' is inactivated while remaining in mesh with the worm gear 8 simultaneously constituting the main cam for the movement of table 7. Displacement of the actuating lever 91 effects engagement of the clutch and a positive connection between the drive shaft 110 and its worm gear 113 with the constantly rotating pulley 111.

Operation As described in the aforementioned copending application, rotation of the main cam disk 8 is translated, via a cam groove and cam follower arrangement, into a rapid forward movement of the table 7 (FIG. 1) for the commencement of the buttonhole-stitching operation. Immediately after this movement of the table 7, a cam 114 with a follower 114 takes over the control of the move- =rnent of the table. Cam 114 which is removably mounted on the spindle 114 is driven by a worm gear 113" as diagrammatically illustrated in FIGS. 1 and 2.

Prior to commencement of machine operation, the appropriate cams 8 and 114, whose cam grooves determine the configuration of the buttonhole to be stitched, are selected. The cam 114 is mounted upon a spindle 114" in the usual manner while adjustment of the severing position is made with the aid of the scale 65 and the head 62. The drive motor is energized and pulley 111 is thereby driven via belt 112 and the fabric F (in FIG. 3) is disposed upon the table 7. Since the lever 92 is now blocked \by the abutment 89, the actuating arm 91 can be displaced to clutch the shaft 111) to the pulley 111 and effect rotation of the

worms

113 and 113". Cam 8 then begins its rotation and rapidly shifts the table 7 with the fabric carried thereon to the right (FIG. 1) into the starting position for the stitching operation. As described in my above identified copending application and in the usual manner, this forward movement of the table '7 is accompanied by a lowering of the

arms

15 and 16 to bring the clamping shoes 13 and 14 into engagement with the fabric and hold it against the respective roughened

surfaces

11 and 12 of the sections 9 and 18 of the table 7. The latter are received within a recess and are provided with guides 18" which permit the shifting of the plate portions 9 and 10 away from one another by a suitable camming arrangement and linkage in the conventional manner. The separating movement of these plates 9 and 10, accompanied by :a similar movement of the

arms

15 and 16 upon their pivot pins 15 and 16', tensions the fabric in the region of the stitchforming means 6 and 6, thereby ensuring that the fabric lies completely flat in this region. The stitching means,

including the needle 6 and the needle operating assembly, the gripper and thread feed arrangement 6' etc. which feed the underthread U and the stay cord G to the stitching location are identical to those described and claimed in my oopending application Ser. No. 328,938 and nee-d not be described here except to note that, upon commencement of the movement of the table 7 subsequent to the rapid forward movement and in its buttonhole-stitching pattern, the stitch forming mechanism 6 and 6' is operated in the usual rhythm. During the stitching of the buttonhole, the table 7 initially moves in its rearward direction and, the region of the eye of the buttonhole, control of the operation is taken over by the cam 114 as previously described. During the initial rearward movement, the stitches S leading to the eye are formed. During the stitching of the eye of the buttonhole, the eccentric stitch forming means 6, 6' swings about the axis Y (FIG. 1) through an angle of approximately Upon the conclusion of the stitching operation, a forward movement of the table 7 results in the stitching of the root portion S with a wedge-shaped configuration prior to severing the threads. From the moment operation commences, abutment 89 prevents any movement in the clockwise sense of the lever 92 about its fulcrum 93.

When the buttonhole is completed, the stitch-forming means 6 .and 6 are brought to a standstill with the needle 6 in its upper dead-center position. The fabric carrying table 7 is thus returned to the position in which severing of the fabric is to be carried out. The button hole-stitching means 115, provided on the head of the machine in the usual manner (FIG. 1), then operates to cut the fabric between the sides of the eye of the buttonhole; such a slitting device is shown in my copending application mentioned above. After slitting of the buttonhole, the table 7 is shifted to its extreme position (to the left as seen in FIG. 1) in which the abutment 89 releases the lever 92 and the

arms

15 and 16 are swung upwardly to release the fabric in the usual manner.

While actuation of the pedal 29 merely tensions the spring 28 without rotating the oscillating shaft 23 when the lever 92 is blocked by the abutment 89, withdrawal of the table 7 permits the clockwise rotation of the lever 92 and the downward movement of slide 99 under the force applied by the pedal 29 and the spring 28. The angulatrly displaceaible shaft 23 is the swung in the clockwise sense (FIGS. 10 and 12) until its formation 26" engages the abutment 31 on housing 1. The lever 33, rigid with shaft 23, is also rotated in the clockwise sense to shift the

levers

35 and 38 to the right from their rest position shown in FIG. 10 to their operative position illustrated in FIG. 12.

The abutments 45 and 46 of

levers

35 and 38, respectively, entrain between them the lever 47 which is then rotated in the clockwise sense (FIGS. 3-6) to swing the axle 48 with respect to the bearing bushing 49 thereof. Lever 53, entrained by the spring 58 with the lever 51, shifts the slide 28 to the preset severing position determined by the position of pin 61 (FIGS. 8 and 9) until further displacement of the slide is impossible. Continued movement of the

arms

35 and 38 swings the lever 47 still further (FIG. 6) to bring the blade 19 into action. The spring connection of the

arms

35 and 38 allows the formation 46 to pass aside, if necessary, and provides a resilient connection within the linkage preventing breakage, should the movable blade be jammed for some reason.

Upon release of the pedal 29, lever 26 swings in the counterclockwise sense (FIGS. 10 and 12) under the restoring force of coil spring 69 (FIGS. 1 and 2) to rotate the shaft 23 into its rest position as illustrated in FIG. 10 wherein the adjusting screw 32 comes to bear upon surface 31 of the housing.

During operation of the thread-severing device, however, the slide 99 is moved into its lower position so that 1 1 lever 106 is held in its clockwise extreme position by the spring 108 and the arm 106 prevents movement of the rod 109 and actuation of the plate shifting and stitch forming mechanism. The auxiliary clamp 17 which is swung into engagement with the fabric during the stitching operation at the beginning of the movement of the table 7 to the right (FIG. 1) and engagement of the pin 86 of lever 82 with the stop 70, remains in engagement with the fabric during the stitching operation and is only elevated after the

blades

18 and 19 have severed the threads U and G. This elevation of the arm 71 with the auxiliary clamping shoe 77 is effected only after the lever 92 and its cam 94 are swung in the clockwise sense about the pivot 93. The latch member 83, whose pin 88' engages members 92 and 94 (FIG. 17), is swung in the clockwise sense about its fulcrum 88" (FIG. 1) and is thus lifted so that the prismatic formation 87 of the lever 82 is freed from the notch 88a which retained the lever 82 in a position in which the spring 84- held the arm 71 in its clockwise position. Upon release of the lever 82 by the lever 88, the spring force no longer holds arm 71 in its clamping position and a torsional coil spring 71 applies sufficient torque to the arm 71 and the shaft 72 to elevate the clamping arm and bring it to the position indicated in FIG. 1 preparatorily to another operating cycle. The

levers

92 and 88 are so dimensioned that the release of the fabric by the auxiliary clamp 17 only occurs when the severing operation has been completed.

In FIGS. 14-16, I show another way of carrying out the actuation of the angularly shiftable shaft 23. In this arrangement, a servomechanism 116 is provided, this servomechanism including a motor 117 (e.g. an electromagnet although fluid responsive and other electrical devices are suitable) having a predetermined stroke and coupled via its armature 117' and a chain 118 to a tension spring 119 which, in turn, engages a lever 120 (FIG. 15) secured to the shaft 23. The magnet 117 is thus capable of actuating the shaft in the same manner as pedal 29. The control of the electromagnet 117 is effected via a switch 121 (diagrammatically illustrated in FIG. 16) which is swingable about a fixed axis 123 but is drawn by a tension spring 124 against a fixed stop 125. In this position, the actuating member 126 of the switch 121 cooperates with an abutment 122 in the manner of a limit switch engageable upon shifting of the plate or table 7 to the left to close an electric circuit to the solenoid or magnet 117. The switch 121, however, is connected via a chain 127 with another lever 128 fastened to the shaft 23. Thus angular displacement of the shaft 23 tends to withdraw the switch 121 out of engagement by the stop 122 to open the circuit to the electromagnet. Switch 121 operates the servomotor 117 automatically to rotate the shaft 23, whose lockout mechanism is identical to that previously described, unless manual operation of the shaft is effected. When the electromagnet is deenergized upon entrainment of chain 127 by the shaft and withdrawal of the switch, the torsion spring 69 returns the shaft to its rest position as previously described.

The invention described and illustrated is believ ed to admit of many modifications within the ability of persons skilled in the art, all such modifications being considered within the spirit and scope of the appended claims.

I claim:

1. In a buttonhole-stitching machine having support means, stitch forming means on said support means for feeding at least an underthread and a stay cord to a stitching location, and a fabric carrying table cooperating with said stitch forming means for positioning a fabric at said location while being generally linearly shiftable on said support means from a starting position at the commencement of a buttonhole-stitching operation with a generally reciprocating movement returning substantially to said position upon conclusion of said operation, the improvement which includes thread-severing means for cutting said underthread and said stay cord upon conclusion of said operation, said thread-severing means comprising: cooperating blade means mounted on said table and engageable with said underthread and said stay cord in the region of said position for severing them upon actuation of said blade means; an angularly oscillatable shaft on said support means operatively connected with said blade means for actuation thereof upon angular displacement of said shaft in one rotational sense; actuating means connectable with said shaft for angularly displacing same in said rotational sense;

mechanism on said support means for selectively blocking and unblocking angular displacement of said shaft; and

abutment means on said table cooperating wtih said mechanism for preventing displacement of said shaft during said reciprocating movement of said table, but permitting displacement of said shaft upon termination of said reciprocating movement.

2. The improvement defined in claim 1 wherein said machine is provided with a drive means for displacing said table and an actuating member for coupling said drive means with said table, said mechanism including means for preventing displacement of said actuating member during rotation of said shaft and operation of said blade means.

3. The improvement defined in claim 2 wherein said shaft is rigid with an arm, said mechanism including a slide member provided with a recess receiving said arm, a control lever fulcrumed to said support means and engaging said slide member for swinging movement about said fulcrum upon displacement of said slide member under entrainment by said arm, said abutment means on said table being disposed in the path of said control lever upon termination of the reciprocating movement of said table for blocking displacement of said control lever, said slide member, said arm and said shaft.

4. The improvement defined in claim 3 wherein said mechanism includes an additional lever engageable by said slide member upon displacement thereof in a direction opposite that in which said slide member is shifted by said arm upon rotation of said shaft in said sense, said additional lever engaging said actuating member for preventing displacement thereof upon rotation of said shaft, said slide member disengaging said additional lever from said actuating member upon return of said shaft to a rest position in which said co-operating blade means is inoperative.

5. The improvement defined in claim 3 wherein said machine includes a main clamping means for holding said fabric against said table during said reciprocating movement of said table, said main clamping means releasing said fabric upon termination of said reciprocating movement, said thread-severing means further comprising auxiliary clamping means on said table engageable with said fabric upon displacement of said table toward said position for holding the fabric against the table during severing of said stay cord and said underthread by said blade means.

6. The improvement defined in claim 5 wherein said auxiliary clamping means includes an arm pivotally connected to said table and having a clamping shoe disposed in the region of the buttonhole, said mechanism including means for disengaging said auxiliary clamping means from said fabric.

7. The improvement defined in claim 6 wherein said auxiliary clamping means comprises a rod pivotally connected to said table, a fabric lever engageable with said rod for displacing same to bring said shoe into clamping engagement with said fabric, spring means biasing said rod away from said fabric, a latching member pivoted to said table and engageable with said further lever for holding said shoe against said fabric in the path of said 13 control lever upon swinging thereof by said arm for disengagement from said further lever.

8. The improvement defined in claim 7 wherein said rod and said further lever have a common pivot, said auxiliary clamping means including a torque spring coupling said rod and said lever at least upon latching engagement of said further lever by said latching member for resiliently holding said rod against said fabric with a force determined by the torque applied by said spring to said rod.

9. The improvement defined in claim 8, further comprising means on said further lever for adjusting the torque of said spring.

10. In an automatic buttonhole-stitching machine, in combination,

support means forming a housing and provided with a generally horizontal sewing machine arm cantilevered above said housing;

stitch forming means on said support means including a generally vertically dis-placeable needle carried by said arm, and means below said needle and cooperating therewith to feed an underthread and a stay cord to said needle at a stitching location, said stitch forming means being swingable through an angle of substantially 180 about a vertical axis at said location for forming a buttonhole eye;

a fabric-carrying table co-o-perating with said stitch forming means for positioning a fabric at said location and generally linearly shiftable on said housing from a starting position at the commencement of a buttonhole-stitching operation with a reciprocating movement returning said table substantially to said position upon conclusion of said operation;

main clamping means carried by said table and swingable thereon for clamping said fabric thereagainst upon commencement of said buttonhole-stitching operation and releasing said fabric upon said termination of said operation;

drive means for displacing said table on said housing and including an actuating member for coupling said drive means with said table at the commencement of said operation;

thread-severing means on said table and said housing and engageable with said underthread and said stay cord upon said termination of said operation in said position of said table to sever said underthread and said stay cord from a completed buttonhole formed on said fabric during said reciprocating movement, said thread-severing means including cooperating blade means mounted on said table, and actuating means on said housing for activating said blade means; and

mechanism on said housing for immobilizing said actuating means during said movement of said table and for preventing activation of said actuating member of said drive means during severing of said underthread and said stay cord.

11. In an automatic buttonhole-stitching machine, in

combination,

support means forming a housing'and provided with a generally horizontal sewing machine arm cantilevered above said housing;

stitch forming means on said support means including a generally vertically displaceable needle carried by said arm, and means below said needle and cooperating therewith to feed an underthread and a stay cord to said needle at a stitching location, said stitch forming means being swingable through an angle of substantially 180 about a vertical axis at said location for forming a buttonhole eye;

a fabric carrying table cooperating with said stitch forming means for positioning :a fabric at said location and linearly shiftable on said housing generally parallel to said arm from a starting position at the commencement of a buttonhole-stitching operation with a reciprocating movement returning said table substantially to said position upon conclusion of said operation;

main clamping means carried by said table and swingable thereon for clamping said fabric thereagainst upon commencement of said buttonhole-stitching op eration and releasing said fabric upon said termination of said operation;

thread-severing means on said table and said housing and engageable with said underthread and said stay cord upon said termination of said operation in said position of said table to sever said underthread and said stay cord from a completed buttonhole formed on said fabric during said reciprocating movement, said thread-severing means including cooperating blade means mounted on said table, and actuating means on said housing for activating said blade means;

mechanism on said housing for immobilizing said actuating means during said movement of said table and for preventing activation of said actuating member of said drive means during severing of said underthread and said stay cord; and

auxiliary clamping means on said table for clamping said fabric thereagainst at least during severing of said underthread and said stay cord by said blade means, said mechanism including means for releasing said auxiliary clamping means from said fabric prior to a subsequent reciprocating movement of said table to form another buttonhole.

12. In an automatic buttonhole-stitching machine, in

combination,

stitch forming means on said support means including a generally vertically displaceable needle carried by said arm, and means below said needle and cooperating therewith to feed an underthread and a stay cord to said needle at a stitching location, said stitch forming means being swingable through an angle of substantially about a vertical axis at said location for forming a buttonhole eye;

a fabric carrying table cooperating with said stitch forming means for positioning a fabric at said location and generally linearly shiftable on said housing from a starting position at the commencement of a buttonhole-stitching opera-tion with a reciprocating movement returning said table substantially to said position upon conclusion of said operation;

said blade means including a slide shiftably mounted on said table in the direction of said reciprocating movement toward and away from said location and carrying a first blade member, a second blade member swingably mounted on said slide and forming a scissor with said first blade member, adjustable stop means on said table limiting displacement of said slide toward said location, first and second levers having a common fulcrum upon said table and respectively engageable with said slide and said second blade member while forming a lost motion linkage with one another, said actuating means including an operating member shiftable on said housing for displacing said second lever, a generally horizontal angularly oscillatable shaft journaled on said housing and operatively connected with said operating member for displacing same upon angular displacement of said shaft in one rotational sense from a rest position, and means for rotating said shaft in said sense; and

13. In an automatic buttonhole-stitching machine, in

combination,

a fabric carrying table cooperating with said stitch forming means for positioning a fabric at said location and shiftable on said housing from a starting position at the commencement of a buttonhole-stitching operation with a reciprocating movement returning said table substantially to said position upon conclusion of said operation;

main clamping means carried by said table and swingable thereon for clam-ping said fabric thereagainst upon commencement of said buttonhole-stitching operation and releasing said fabric upon said termination of said operation;

thread-severing means on said table and said housing and engageable With said underthread and said stay cord upon said termination of said operation in said position of said table to sever said underthread and said stay cord from a completed buttonhole formed on said fabric during said [reciprocating movement, said thread-severing means including cooperating blade means mounted on said table, and actuating means on said housing for activating said blade means; and

said blade means including a slide shiftably mounted on said table in the direction of said reciprocating movement toward and away from said location and carrying a first blade member, a second blade member swingably mounted on said slide and forming a scisso-r with said first blade member, adjustable stop means on said table limiting displacement of said slide toward said location, first and second levers having a common fulcrum upon said table and respectively engage-able with said slide and said second blade member while forming a lost motion linkage with one another, said actuating means including an operating member shiftable on said housing for displacing said second lever, a generally horizontal angularly oscillatable shaft journaled on said housing and operatively connected with said opera-ting member for displacing same upon angular displacement of said shaft in one rotational sense from a rest position, and means for rotating said shaft in said sense; and

mechanism on said housing for immobilizing said actuating means during said movement of said table and for preventing activation of said actuating member of said drive means during severing of said underthread and said stay cord;

said mechanism including an arm carried by said shaft and displacea-ble together therewith in said sense, a generally vertically displaceable slide member on said housing coupled with said arm and entrainable therewith upon angular displacement of said shaft, and a control lever fulcrumed on said housing and engageable with said slide member for selectively permitting and preventing movement thereof, said table being provided with abutment means disposed in the path of said control lever during said reciprocating movement of said table and out of the path of said control lever in said position of said table for blocking rotation of said control lever, shifting of said slide member and angular displacement of said shaft until said table returns to said position.

14. In an automatic buttonhole-stitching machine, in

combination,

a fabric carrying table cooperating with said stitch forming means for positioning a fabric at said location and shiftable on said housing generally parallel to said arm from -a starting position at the commencement of a buttonhole-stitching operation with a reciprocating movement returning said table substantially to said position upon conclusion of said operation;

said blade means including a slide shiftably mounted on said table in the direction of said reciprocating movement toward and away from said location and carrying a first blade member, a second blade member swingably mounted on said slide and forming a scissor with said first blade member, adjustable stop means on said table limiting displacement of said slide toward said location, first and second levers having a common fulcrum upon said table and respectively engageable with said slide and said second blade member while forming a lost motion linkage with one another, said actuating means including 18 position of said table to sever said underthread and said stay cord from a completed buttonhole formed on said fabric during said reciprocating movement, said thread-severing means including cooperating an operating member shiftable on said housing for blade means mounted on said table, and actuating displacing said second lever, a generally horizontal means on said housing for activating said blade angularly oscillatable shaft journaled on said housmeans, said blade means including a slide shiftably ing and operatively connected with said operating mounted on said table in the direction of said recipmember for displacing same upon angular displacerocating movement toward and away from said locament of said shaft in one rotational sense from a tion and carrying a first blade member, a second rest position, and means for rotating said shaft in blade member SWingablY mounted 011 Said Slide and said sense; and forming a scissor with said first blade member, admechanism on said housing for immobilizing said actuiustable p means on said table l ing i pl ating means during said movement of said table and ment of Said Slide toward said location, first and for preventing activation of said actuating member Second levers having a Common fulcrum uP011 said of said drive means during severing of said undertable and respectively engegeable With Said slide and thread and said stay cord; and said second blade member while forming a lost auxiliary clamping means on said table for clamping motion linkage w one another, Said actuating said fabric thereagainst at least during severing of means including an Operating Inember Shiflable on said underthread and said stay cord by said blade Said housing for displacing Said Second lever, a means, said mechanism including means for releaserally hefilental angularly eseillatable Shaft i ing said auxiliary clamping means from said fabric flaled 011 said housing and operatively connected prior to a subsequent reciprocating movement of said With Said Operating member for displacing same table to form another b tt h l d upon angular displacement of said shaft in one said mechanism including an arm carried by said shaft relational sense from a Test Position, and means for and displaceable together therewith in said sense, a rotating said shaft in said sense; and generally vertically displaceable, lid member on mechanism on said housing for immobilizing said actusaid housing coupled with said arm and entrainable ating means during said movement of Said table and therewith upon angular displacement of said shaft, for Preventing activation of said actuating member and a control lever fulcrurned on said housing and of said drive means during severing of said under engageable with said slide member for selectively thread and Said y Cord, said mechanism including permitting and preventing movement thereof, said an arm Carried by said shaft and displaeeable table being provided with abutment means disposed gethel' therewith in said sense, a generally Vertically in the path of said control lever during said reciprodisplaeeable slide member on Said housing Coupled cating movement of said table and out of the path With said arm and entrainable therewith uP011 enguof said control lever in said position of said table lar displacement of said shaft, and a Control lever for blocking rotation of said control lever, shifting fulcrumed on said housing and engageable With Said of said slide member and angular displacement of slide member for selectively Permitting and P said shaft until said table returns to said position. ing movement thereof said table being Provided 15. In an automatic buttonhole-stitching machine, in 40 with abutment means disposed in the P of said ombi ti control lever during said reciprocating movement of support means f i a h i and provided with a said table and out of the path of said control lever generally horizontal sewing machine arm cantilevered in said Position of said table for blocking rotation above id h i of said control lever, shifting of said slide member stitch forming means on said support means including and angular displasementff said shaf t until said a generally vertically displaceable needle carried by m returns to sa 1d P 3 s shde msmbsr said arm, and means below said needle and cooperbelng ge e Yvlth sald retamulg member the ti th i h to f d an underthread and a Stay rest position of said shaft for holding said retaining cord to said needle at a stitching location, said stitch mFmber out of blockisg relationship w said actu f i means b i swingable through an angle of at ng member to permit coupling of said drive means substantially 180 about a vertical axis at said loca- Wlth Said table said rest Posinon of said i i f f r i a buttonhole 16. In an automatic buttonhole-stitching machine, in a fabric carrying table cooperating with said stitch combmatlon forming means for positioning a fabric at said loca- Support means f hqusmg Provlded a tion and shiftable on said housing from a starting generally T .sewmg machme arm canine position at the commencement of a buttonhole-stitch- .vered abfwe said housm v i ing operation with a reciprocating movement return- Stltch forming f' on ,Sald Support means f a ing said table substantially to said position upon congeperany Vemcany dlsplaceafble medle by clusion of Said operation; sa1d arm, and means below said needle and cooperatmain clamping means carried by said table and swingmg h W to an underth,read 9 Stay cord able thereon for clamping said fabric thereagainst F 531d needleiat a st.1tChIng1oOatwn Sald Stltch form" upon commencement of said buttonhole-stitching mg l belfilg Sw'1ngab1e t h an angle of i operation and releasing Said fabric upon Said tap stantially 180 about a vertical axis at sa1dlocat1on mination of said operation; for fprmmg 2} buttonhole eye; fabric carrying table cooperating With said stitch dnve f dlsplaims Sald table on Sald P01151115; forming means for positioning a fabric at said locaf mcludmg aqua/[mg member for couphng sald tion and shiftable on said housing generally parallel drive means w th said table at the commenceme to said arm from a starting position at the commence- Of Sflld Operation, Sald table belIlg Pfevlded Wlth ment of a buttonhole-stitching operation with a a pivotal retaining member disengageably pring reciprocating movement returning said table substanbiased into movement blocking relationship with tially to said position upon conclusion of said operasaid actuating member; tion; thread-severing means on said table and said housing main clamping means carried by said table and swingand engageable with said underthread and said stay able thereon for clamping said fabric the-reagainst cord upon said termination of said operation in said upon commencement of said buttonhole-stitching opdrive means for displacing said table on said housing and including an actuating member for coupling said drive means with said table at the commencement of said operation, said table being provided with a pivotal retaining member disengageably spring-biased into movement blocking relationship with said actuating member;

thread-severing means on said table and said housing and engageable with said underthread and said stay cord upon said termination of said operation in said position of said table to sever said underthread and slide toward said location, first and second levers having a common fulcrum upon said table and respectively engageable with said slide and said second blade member while forming a lost motion linkage With one another, said actuating means including an operating member shiftable on said housing for displacing said second lever, a generally horizontal angularly oscillatable shaft journaled on said housing and operatively connected with said operating member for displacing same upon angular displacement of said shaft in one rotational sense from rest position, and means for rotating said shaft in said sense;

mechanism on said housing for immobilizing said actuating means during said movement of said table and for preventing activation of said actuating member of said drive means during severing of said underthread and said stay cord, said mechanism including an arm carried by said shaft and displaceable together therewith in said sense, a generally vertically disp-lacea ble slide member on said housing coupled with said arm and entrainable therewith upon angular displacement of said shaft, and a control lever fulcrumed on said housing and engageable with said slide member for selectively permitting and preventing movement thereof, said table being provided With abutment means disposed in the path of said control lever during said reciprocating movement of said table and out of the path of said control lever in said position of said table for blocking rotation of said control lever, shifting of said slide member and angular displacement of said shaft until said table returns to said position, said slide member being engageable with said retaining member in the rest position of said shaft for holding said retaining member out of blocking relationship with said actuating member to permit coupling of said drive means with said table in said rest position of said shaft; and

auxiliary clamping means on said table for clam-ping said fabric thereagainst at least during severing of said underthread and said stay cord by said blade means, said mechanism including means for releasing said auxiliary clamping means from said fabric prior to a subsequent reciprocating movement of said table to form another buttonhole.

17. In an automatic buttonhole-stitching machine, in

combination,

support means forming a housing and provided with a generally horizontal sewing-machine arm cantilevered above said housing;

stitch forming means on said support means including a generally vertically displaceable needle carried by said arm, and means below said needle and cooperating therewith to feed an underthread and a stay cord to said needle at a stitching location, said stitch forming means being swinga ble through an angle of sul stantially about a vertical axis at said location for forming a buttonhole eye;

a fabric carrying tab-1e cooperating with said stitch forming means for positioning a fabric at said location and shiftable on said housing generally parallel to said arm from a starting position at the commencement of a buttonhole-stitching operation with a reciprocating movement returning said table substantially to said position upon conclusion of said operation;

thread-severing means on said table and said housing and engage-able with said underthread and said stay cord upon said termination of said operation in said position of said table to sever said underthread and said stay cord from a completed buttonhole formed on said fabric during said reciprocating movement, said thread-severing means including cooperating blade means mounted on said table, and actuating means on said housing for activating said blade means, said blade means including a slide shiftably mounted on said table in the direction of said reciprocating movement toward and away from said location and carrying a first blade member, a second blade member swingably mounted on said slide and forming a scissor with said first blade member, adjust-able stop means on said table limiting displacement of said slide toward said location, first and second levers having a common fulcrum upon said table and respectively engageable with said slide and said second blade member while forming a lost motion linkage with one another, said actuating means including an operating member shiftable on said housing for displacing said second lever, a generally horizontal angularly oscillatable shaft journaled on said housing and operatively connected with said operating member for displacing same upon angular displacement of said shaft in one rotational sense from a rest position, and means for rotating said shaft in said sense;

mechanism on said housing for immobilizing said actuating means during said movement of said table and for preventing activation of said actuating member of said drive means during severing of said underthread and said stay cord, said mechanism including an arm carried by said shaft and displaceaible together therewith in said sense, a generally vertically displacea-ble slide member on said housing coupled 'with said arm and entrainable therewith upon angular displacement of said shaft, and a control lever fulcrumed on said housing and engageable with said slide member for selectively permitting and preventing movement thereof, said table being provided with abutment means disposed in the path of said control lever during said reciprocating movement of said table and out of the path of said control lever in said position of said table for blocking rotation of said control lever, shifting of said slide member and angular displacement of said shaft until said table returns to said position; and

auxiliary clamping means on said table for clamping said fabric thereag-ainst at least during severing of said underthread and said stay cord by said blade on said table and engageable with said third lever to releasably retain it in said operative position of said third lever, said control lever engaging said latching member to release said third lever upon displacement of said slide member by said arm and said shaft.

table to form another buttonhole, said auxiliary clamping means including a rod pivotally mounted 5 on said table and provided with a fabric engaging clamping shoe, a third lever journaled on said table for rotation about the pivotal axis of said rod, torsion spring means coupling said third lever and said References Cited by the Examiner UNITED STATES PATENTS 271,666 2/1883 Sullivan et a1. 1l2253 X rod for resiliently urging said rod and said shoe 10 757,463 4/1904 Hogan 12 253 X against the fabric upon rotation of said third lever 1 0 555 2 1920 Seafle 112 .71 into an operative position from a rest position about 1 7 7,92 1 1931 Carlson 112-253 said axis, further abutment means on said housing 2,324,235 7/ 1943' Pikul 112-71 cooperating with said third lever upon displacement 2,778,329 1/1957 Howell et al. 11 2199 of said table to bring said shoe to bear upon the fabric, and a latching member swingably mounted FRANK COHEN, Primary Examiner.

Claims

1. IN A BUTTONHOLE-STITCHING MACHINE HAVING SUPPORT MEANS, STITCH FORMING MEANS ON SAID SUPPORT MEANS FOR FEEDING AT LEAST AN UNDERTHREAD AND A STAY CORD TO A STITCHING LOCATION, AND A FABRIC CARRYING TABLE COOPERATING WITH SAID STITCH FORMING MEANS FOR POSITIONING A FABRIC AT SAID LOCATION WHILE BEING GENERALLY LINEARLY SHIFTABLE ON SAID SUPPORT MEANS FROM A STARTING POSITION AT THE COMMENCEMENT OF A BUTTONHOLE-STITCHING OPERATION WITH A GENERALLY RECIPROCATING MOVEMENT RETURNING SUBSTANTIALLY TO SAID POSITION UPON CONCLUSION OF SAID OPERATION, THE IMPROVEMENT WHICH INCLUDES THREAD-SEVERING MEANS FOR CUTTING SAID UNDERTHREAD AND SAID STAY CORD UPON CONCLUSION OF SAID OPERATION, SAID THREAD-SEVERING MEANS COMPRISING: COOPERATING BLADE MEANS MOUNTED ON SAID TABLE AND ENGAGEABLE WITH SAID UNDERTHREAD AND SAID STAY CORD IN THE REGION OF SAID POSITION FOR SEVERING THEM UPON ACTUATION OF SAID BLADE MEANS; AN ANGULARLY OSCILLATABLE SHAFT ON SAID SUPPORT MEANS OPERATIVELY CONNECTED WITH SAID BLADE MEANS FOR ACTUATION THEREOF UPON ANGULAR DISPLACEMENT OF SAID SHAFT IN ONE ROTATIONAL SENSE; ACTUATING MEANS CONNECTABLE WITH SAID SHAFT FOR ANGULARLY DISPLACING SAME IN SAID ROTATIONAL SENSE; MECHANISM ON SAID SUPPORT MEANS FOR SELECTIVELY BLOCKING AND UNBLOCKING ANGULAR DISPLACEMENT OF SAID SHAFT; AND ABUTMENT MEANS ON SAID TABLE COOPERATING WITH SAID MECHANISM FOR PREVENTING DISPLACEMENT OF SAID SHAFT DURING SAID RECIPROCATING MOVEMENT OF SAID TABLE, BUT PERMITTING DISPLACEMENT OF SAID SHAFT UPON TERMINATION OF SAID RECIPROCATINNG MOVEMENT.