US2684651A - Automatic guiding mechanism for sewing machines - Google Patents

Description

L. BIHALY July 27, 1954 AUTOMATIC GUIDING MECHANISM FOR SEWING MACHINES 4 Sheets-Sheet 1 Filed Dec. 16, 1950 b/" 7, 1954 BIHALY 2,684,651

AUTOMATIC GUIDING MECHANISM FOR SEWING MACHINES Filed Dec. 16, 1950 4 Sheets-Sheet 2 July 27, 1954 B|HALY 2,684,651

AUTOMATIC GUIDING MECHANISM FOR SEWING MACHINES Filed Dec. 16, 1950 4 Sheets-Sheet 3 F I! a L. BIHALY July 27, 1954 AUTOMATIC GUIDING MECHANISM FOR SEWING MACHINES 4 Sheets-Sheet 4 Filed Dec. 16. 1950 Patented July 27, 1954 UNITED STAT Fit:

AUTOMATIC GUIDING MECHANISM FOR SEWING MACHINES 6 Claims. 1

The invention concerns an apparatus capable of guiding the workpiece under the needle of a sewing machine along a predetermined stitching line, especially in the production of large numbers of identical parts requiring close tolerances, for example mens collars. The apparatus is especially suitable for the production of the edge stitch of such collars, particularly of collars of the so-called one-piece variety where top and band of each layer are out together. It can be, however, used with advantage for the production of other smaller garments or garment-parts, for example cuifs or pockets.

According to present practice, the edge stitch, i. e. the stitch uniting the'fabric layers comprising the garment or garment-part is produced by guiding the fabric layers by hand under the needle, whereby the tangential component of the movement is imparted to the workpiece by a rifled feed dog and any radial displacement is produced by the hand of the stitcher. This method of guiding introduces some slippage of the layers of which a garment is composed in relation to each other, especially at places where the radial component is appreciable, i. e. where the stitching line is markedly curved. This slippage results in distortions which prevent the work piece from lying fiat on the table after stitching and introduces bagginess into one or the other layer of the garment when it is turned inside out comprising the garment in a suitable frame and guiding this frame mechanically under the needle of a sewing machine along a path corresponding to the desired line of stitch. One published method comprises the useof a support for the workholder frame, equipped with two pins each sliding in one of two identical channels cut to the shape of the required line of stitch; This line of stitch is assumed to be extensive inone main direction, and rather limited in its deviation from that direction so'that moving the workholder in the main direction willforce it to follow the line of stitch. This movement can be produced by conventional means, similar to the feed dog .of ordinary sewing machines. Such an apparatus, while improving the production of certain shapes of stitching, is incapable of producing steep curves or sharp points, and therefore rather limited in its application, V

According to the invention'any shape of stitch ing' can be produced by the use oftwo independently controlled guiding means, each of which determines one coordinate of the position of the work-piece in relation to the needle. One of these guiding means can be made to act directly on the workholder, while the other preferably acts on a support, relative to which the workholder can be moved freely in the direction of one of the coordinates.

Although the two coordinates are suitably rec tilinear, it is possible to use at least one curved coordinate, e. g. one defined by the arc of a circle. It is also possible to combine a linear coordinate with an angular displacement representing the other coordinate. If linear coordinates are used they need not necessarily be orthogonal, but in the preferred embodiment of the invention linear, orthogonal coordinates in the horizontal sewing plane are used. For the sake of convenience the coordinate extending in the direction of the sewing machine axis will in the following be described as running in a north-south direction, while the horizontal coordinate, perpendicular to it, will be referred to as running in an east-west direction, considering the horizontal plane of stitching as a map.

The use of two independent guiding means each representing one out of two coordinates has considerable advantages in comparison with direct control by means of guide tracks always parallel to the desired stitching line. The method according to the invention permits, as long as the line is continuous and unicursal, the production of a stitching line of practically any shape or form, i. e. including sharp points and loops.

The subdivision of the guiding movement into two components has the further advantage that by proper shaping or selection of the guiding means the stitch length can be varied in such a way that portions oi the seam requiring a reinforcement or strongly curved portions of the seam are sewn with a shorter, stitch length than other portions of the seam.

In an apparatus according to the invention the workpiece is inserted into a workholder, e. g. a frame. In accordance with the basic principle of the invention the guiding means controlling the movement of the workholder in the plane of stitching is divided into two separate components. For this purpose the guiding means comprises two individual positioning units movable in the plane of stitching, preferably at right angles to each other, one of these units carrying the workholder and being movably disposed on the other unit, and each of the positioning'unitsbeing independently movable by one each of a pair of controlling means disposed on a common shaft.

As controlling means are suitably profiled elements, for example cylindrical or fiat cams can be chosen, but alternatively punched cards or any other storing apparatus for quantitative data can be used. The preferred apparatus here described is controlled by cams which are connected to the workholder or its support by rigid mechanical linkages.

The cams used for controlling the motion of the Workholder are preferably arranged on a shaft driven by the main shaft of the sewing machine. It is, of course, important to make the drive intermittent so that the cams act only when the needle is free of the fabric assembly. One arrangement accomplishing this intermittent drive and forming an essential part of the present invention comprises a worm, the slope of which is so steep that the full pitch of the thread is reached during less than one complete revolution. In this case the remainder of the thread is either formed without a slope or completely cut away.

The enclosed drawings show diagrammatically an arrangement for the production of the first row of stitches on mens one-piece collars:

Fig. 1 shows the complete assembly.

Fig. 2 shows details of the controlling n1echanism.

Fig. 3 shows the workholder frame with the intended line of stitch indicated.

Fig. 4 shows the two cams controlling the two independent motions.

Fig. 5 is a diagrammatic drawing of the cam profile controlling the east-west motion.

Fig. 6' is a similar drawing of the cam profile controlling the north-south motion.

Fig. '7 shows the stitching plan of the first row of stitches in a mens one-piece collar.

Fig. 8 shows details of the intermittent drive connecting the main shaft of the sewing machine with the shaft rotating the two cams.

Fig. 9 shows details of the start-stop mechanism.

Letter A in Fig. 1 indicates the frame of the controlling mechanism according to the invention, letter B designating a sewing machine mounted in the frame, and letter 0 indicates the visible part of the controlling mechanism. This arrangement is, of course, only one of several arrangements feasable according to the invention: for example, it may be possible to design the control mechanism as an integral part of the sewing machine itself.

Frame I in Fig. 3 is adapted to grip the three fabric layers, ordinarily required in the produc tion of the collar, at their narrow ends. The two ends of the workholder are for this purpose equipped with clamps 2 (Fig. 3) which can be studded with pins 2a (Fig. 3) for safe location of the fabric blanks.

Frame I is equipped with locating lugs or pins 3 which coact with lugs or holes in part H oi the workholder ill. The workholder is movable and consists essentially of the horizontal plate 12 and of two vertical ribs !3 arranged under-- neath. These are connected by rod 13a running in the north-south direction. Below plate i? there is a sleeve M with a cylindrical bore running in the east-West direction, sliding along a crossbar 2i running in the same direction.

Each end of the crossbar 2! is rigidly connected with one of a. pair of sleeves 22. These are capable of sliding in the north-south direction on two lateral main guide bars 23, rigidly anchored in frame A.

By sliding workholder H] by an appropriate amount in the east-West direction along the crossbar 2| and sliding this crossbar with its sleeves 22 by an appropriate amount along the main guide bars 23, the workholder can be brought into any desired position relative to the needle.

For the sake of convenience the rigid system consisting of sleeves 22 and crossbar 2| will be referred to as system 20.

This system which determines the north-south position of the workholder is controlled by two levers 24 arranged at the sides of the machine and oscillating with shaft 25 which is journalled at the bottom of the frame in bearings 26. The connection between levers 24 and the coacting slides for system 20 is shown as consisting of a pair of slots 24a and a pair of pins 220., but equivalent means can of course be substituted.

The east-west motion is brought about by lever i5 journalled on shaft l6. As lever I? must be of variable length, its upper end [5a is telescopi cally extensible. A sleeve |5b is fixed to this end of lever I 5 with a bore in the north-south direction sliding on rod I3a between the vertical ribs l3. These ribs l3 are spaced sufficiently apart to permit the necessary motion of the workholdcr in the north-south direction Without sleeve [51) touching either of the ribs.

The lower end i 50 of lever [5 serves as a guide for a sleeve I3 carrying pin Isa. This pin transmits the required motion to the lever I5.

A pin 28 arranged on one of the levers 2:; serves as a pick-up for the drive controlling the northsouth motion of levers 24.

The controlling means proper are disposed on a common horizontal shaft 30 extending in the east-west direction. The controlling element for lever is consists of a drum or cylinder secured to shaft 30. A helical guide track 32 is cut into the face of the cylinder 3|, the said guide track producing a complete cyle of the east-west motion upon a complete revolution of the cylinder 3i aroundthe shaft 39. A pin 33 following the guide track 32 is fixed at one end of aconnecting rod Hi, the movement of which isrestricted to a sliding motion in the east-west direction by an arrangement not shown in the drawings. In this way pin Isa, fixed at the other end of rod #9 and connecting the same with sleeve I8, is forced to reproduce exactly the motion of pin 33. Thus, the mechanical connection between the control ling element 32 and the \vorlrholder I0 is closed leaving the north-south motion of the workholder completely free.

The north-south motion is similarly controlled by groove 35 in a disk cam 34 which is also secured to shaft 30. The movement is transferred by means of pin 28 to one of the interconnected levers 24 and therefrom to system 20. Thus, appropriate shaping of grooves 32 and 35 can produce any desired line of stitching. The stitching line designated as 36 in Fig. 3 and defining the contour of a one-piece collar along three sides of the workpiece is, for example, obtained by giving grooves 32 and 35 the shape indicated in Figs. 5 and 6 respectively. The graduation shown in Figs. 5 and 6 refers to the angular displacement of shaft 30 and the controlling means secured thereto, i. e. cylinder 3! and disk, 34, one complete revolution of shaft an representing a complete working cycle, i. e. the formation of a row of stitches along three sides of a one-piece collar. By giving the grooves 32 and 35 the shape shown in Figs. 5 and 6, the strongly curved parts of the stitching lines are sewn with a shorter stitch length than the straight or slightly curved portions of the stitching line. Thus, as shown in Fig. 7, the part of the stitching line between 0 and 110 is made with smaller stitches than the part between 110 and 250.

In the embodiment of the guiding means according to the invention as described above and shown in Figs. 2-6, of the drawings, the guide tracks are shaped so as to make one revolution of shaft correspond to one complete working cycle. This means that after one complete revolution of shaft 30 by 360 the work-piece has been shifted from a position essentially to the left of the needle to a position essentially to the right of the needle. In this case measures must be taken to shift frame I back into the starting position prior to the initiation of the next working cycle.

Instead of the arrangement here described for returning frame I to the starting position after the completion of one working cycle other methods may be applied. For example, the guide tracks may be designed in such a Way that a complete revolution of shaft 30 not only produces a movement of the work-piece along the desired stitching line but also the return of the frame to the starting position. In this case it is advantageous to prevent the sewing machine from forming proper stitches, e. g. by preventing the upper yarn from forming loops during the return movement of the needle. It is also possible to design the guide tracks in a similar way as described above for guiding the workholding frame I only along the actual stitching line during one complete revolution of the control shaft and to provide the machine with a reversing gear permitting the next working cycle to be performed in the opposite direction.

The arrangement illustrated in the drawings comprises means for interrupting the motion of the frame when the needle penetrates the work piece. For this purpose the driving mechanism shown in detail in Fig. 8 is used. This mechanism comprises a shaft driven by the main shaft of the sewing machine through a sprocket wheel and chain connection 4| at the same speed as the sewing machine shaft. Alternatively shaft 00 may be identical with the main shaft of the sewing machine. Thus, one revolution of shaft 40 always corresponds to one stitch performed by the needle. A worm 42 is fixed to one end of shaft 00, the worm acting, directly or through intermediate gearing 13, upon the cog wheel M secured to shaft 30. Thus, one complete revel-wtion of the main shaft of the sewing machine will rotate shaft 30 and parts 3! and 3t through a given (small) angle. The gear ratio is selected so that one complete revolution of shaft 30 requires a somewhat greater number of revolutions of the sewing machine shaft than the number of stitches necessary for completing one working cycle. Since 340-350 stitches are sufficient to produce a seam around three sides of the con-- tour of a mans collar, in the apparatus described, the gear ratio is such that each complete revolution of the main shaft of the sewing machine turns shaft 30 through approximately one degree.

The helical thread of worm 42 is of an unusual type adapted to convert the continuous rotation of shaft 00 into an intermittent rotation of shaft 30. For this purpose the slope Of the thread is, increased so that the meshing cog wheel is advanced by one cog when shaft 40 has been turned through about half a revolution. As appears from Fig. 8, the thread is cut away on the remaining portion of the surface of the worm so that the worm 42 and the cog wheel 43 are out of mesh during that part of the revolution. In order to facilitate smooth reengagement of worm and wheel, shaft 30 is prevented from overrunning owing to elasticity or inertia forces. Means for this purpose may for instance consist of indexing disk 45 fixed to the shaft carrying the gear wheels 43. This indexing disk cooperates with the spring biased pawl 40 the index positions of which correspond to the stationary positions of the gearing shaft.

To ensure easy handling of the work it is desirable to provide means stopping the sewing machine upon completion of the desired number of stitches and with the needle free of the Workpiece. A suitable arrangement is shown in Fig. 9. Shaft 40 which is identical or synchronized with the main shaft of the sewing machine is provided with cam IOI having a stop face I02. The cam IOI is yieldingly connected with shaft 00, e. g. by means of two helical springs I03 having a comparatively high bias. In other words the moment necessary to rotate cam IIJI around shaft 00 by one degree is comparatively high. The stop face I02 of the cam is adapted to cooperate with stop lever I00 which during the operation of the machine is held free of the cam by means of a latch I04. Lever I00 is biased towards cam IOI by a spring II3 to compensate for its inertia. The latch I04 is actuated by a rod I05 which. in turn is acted upon by one of the levers '24. Obviously the stop mechanism may also be brought into operation directly from the guide shaft 30 or any equivalent part of the apparatus. In the embodiment shown in Fig. 9 stop rod I05 is biased by a weak spring towards lever 24 but so restricted in its movement that it will not come into contact wtih lever 24 unless this lever has practically reached its northernmost position and the stitching has been carried to its southernmost end but for a few stitches. While these few last stitches are performed rod I05 is pushed northwards thereby lifting the latch I04 by means of a stop I06. By suitable adjustment of stop I00 this action can easily be timed to coincide with a certain final stitch. Spring H3 then lowers stop lever I00 which during the next transport period stops shaft 40. Simultaneously rod I05 stops the motor by means of switch H2. If the operator intends to stop the machine before the stitching is completed the same sequence can be initiated by pressing button I0! at the forward end of the rod I05.

Prior to resuming operation of the machine, stop lever I00 must be lifted again. This is performed by rocking finger I00 on shaft I00 with the aid of lever I I0. The handle of this lever is so positioned that in the stop position of the machine it covers starting knob HI. Thus, this knobl can only be pressed and the motor restarted after the operator has moved lever H0 and thus freed cam IOI.

What is claimed is:

1. Automatic mechanism for guiding a workholder past the needle of a sewing machine in accordance with a predetermined line of stitching, said guiding mechanism comprising: a frame structure in fixed relation to a sewing machine; a pair of bars fixed in the frame structure and extending in parallel to the main shaft of the sewing machine; a pair of sleeves each slidable on one of said bars; a crossbar extending at right angles to and rigidly connecting said sleeves;

means carrying a workholder and slidably disposed on said crossbar; a pair of levers rigidly connected at one end to a common axis journalled in the frame structure in parallel to said crossbar, the other end of each of the levers operatively engaging one of said sleeves; a third lever journalled at one end in the frame struc ture for swinging in the direction of said crossbar and operatively engaging said means carrying the workholder; first cam means secured to a cam shaft and cooperating with a cam follower rigidly connected to one lever of said pair of levers second cam means secured to cam shaft and cooperating with a cam follower rigidly connected to said third lever, both said cam means being shaped so that at any time during a work ing cycle the position of the workholder in relation to the needle as required for the realisation of; the desired line of stitching is jointly determined both cams; and means driving said shaft in predetermined time relation to the sewing machine drive.

2. In the automatic guiding mechanism according to claim 1 the feature that said means carrying the workholder comprises a horizontal plate, holding means on said plate adapted to grip a workholder; a first sleeve rigidly fixed to the lower side of said plate and adapted to slide on said crossbar; side walls extending downwardly from said plate in parallel to said crossbar; a

bar extending between said side walls below said first sleeve at right angles to said crossbar; and a second sleeve slidably disposed on said bar extending between said side walls, said second sleeve being operatively connected to said third lever to transmit the movements thereof to the workholder carrying means independently of lateral shifting of the crossbar in relation to the swinging plane of said third lever.

3. In an automatic guiding mechanism according to claim 1, a stop mechanism comprising: a shaft transmitting power from the main shaft of the sewing machine to the driving means of the guiding mechanism; a cam on said power transmitting shaft; a stop lever adapted to engage said cam in a position in which the needle is outside the workpiece; a latch normally holding the stop lever in a resting position in which the cam is not engaged; and means actuated by one of the members of the guiding mechanism approaching its final position at the end of the stitching cycle to. trip said latch.

4. In an automatic guiding mechanism according to claim 1, a stop mechanism comprising: a shaft transmitting power from the main shaft of the sewing machine to the driving means of the guiding mechanism; a cam on said power transmitting shaft; a stop lever adapted to engage said cam in a position in which the needle is outside the workpiece; a latch normally holding the stop lever in a resting position in which the cam is not engaged; and manually actuated means for tripping said latch at any time during the stitching cycle.

5. Automatic mechanism for guiding a workholder past the needle of a sewing machine in accordance with a predetermined line of stitching, said guiding mechanism comprising first positioning means slidable on a stationary support in one direction in a plane parallel to the sewing plane, second positioning means adapted to carry said workholdcr and disposed on said first positioning means for sliding movement thereon in a plane parallel to the sewing plane at right angles to said first direction-first and second cam means disposed on a common shaft and cooperating with respectively first and second cam followers, first link means operatively connecting said first cam follower to said first positioning means and second link means operatively connecting said cam follower to said second positioning means, both said cams being shaped so that at any time during a working cycle the position of the workholder in relation to the needle as required for the realisation of the desired line of stitchin is jointly determined by both cams, power transmitting means for connecting the main shaft of the sewing machine with said cam shaft, said power transmitting means comprising gearing means including a worm meshing with a cog wheel, the slope of the thread of the worm being so steep that the meshing COgwheel is advanced by one cog during less than a complete revolution of the worm, the portion of the thread of the worm in excess of the portion needed for advancing the meshing cog wheel by cog during one revolution of the worm being cut away and indexing means adapted to prevent the co wheel from bein inadvertently oscillated while being out of mesh with the threaded portion of the worm.

6. In an automatic work guiding mechanism for use in cooperation with a sewing machine: a work. holder, work holder positioning elements guidably movable in respectively the direction of the main shaft of the sewing machine and in a direction perpendicular to said main shaft for coordinate adjustment of the position of the work holder in the sewing plane in relation to the needle of the sewing machine, guiding elements each acting upon one of the work holder positionin elements for suc essive coordinate adjustment of the work holder in position corresponding to a line of stitching of predetermined shape and composed of stitches of a length individually predetermined independently of the fixed rate at which stitches are formed by the sewing machine, each of said guiding elements having successive portions each corresponding to a successive stitch of said line of stitching and adapted to shift the respective work holder positioning element in its direction of movement over a distance corresponding to respectively the advance of the work holder and work in the in cidentaliy prevailing main direction of the stitching line, thereby to control the stitch length at will, and the advance of the work holder and Work perpendicularly to said incidentally prevailing main direction of the stitching line, thereby control the direction of stitching, said per tions of that of the guiding elements controlling the stitch. length for an actually prevailing main direction of stitching being shaped for relatively decreased advance of the work holder in said main direction of stitching, thereby to reduce the stitch length, when the correspondin portions or the other guiding element are shaped for c0ntinuous substantial variation of the direction of stitching i. e. for forming a strongly curvedv portion of said predetermined line of stitching.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 268,804 Keith et al Dec. 12, 1-382 349,090 I-Iappe Sept. 14, 1886 447,570 Koch Mar. 3, 1891 813,908 Miller et al Feb. 27, 1906 1,559,970 Meahl Nov. 3, 1925 2,382,486 Kelly Aug. 14, 1945

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