US3509838A - Sewing machine for attaching articles to workpieces - Google Patents

Description

SEWING MACHINE FOR ATTAOHING ARTICLES TO WORKPIE'CES Filed Jan. 7, 1969 R- E. BOWIN May 5, 1970 4 Sheets-Sheet 1 R. EvBOWlN 3,509,838

SEWING MACHINE FOR ATTACHING ARTICLES I'O WORKPIECES May 5, 1970 4 Sheets-Sheet 2 Filed Jan. 7, 1969 ii N v gum R. E. BOWIN May 5, 1970 SEWING MACHINE FOR ATTACHING ARTICLES TO WORKPIECES Filed Jan. 7, 1969 I .4 Sheets-Sheet 3 y 1970 R. E. BOWIN v 3,509,838

SEWING MACHINE FOR ATTACHING ARTICLES T0 WORKPIECES Filed Jan. 7, 1969 4 Sheets-Sheet 4 FIG.8.

United States Patent 3,509,838 SEWING MACHINE FOR ATTACHING ARTICLES T0 WORKPIECES Richard E. Bowin, Chicago, Ill., assignor to Union Special Machine Company, Chicago, 11]., a corporation of Illinois Filed Jan. 7, 1969, Ser. No. 789,446 Int. Cl. D05b 3/14 U.S. Cl. 112'110 26 Claims ABSTRACT OF THE DISCLOSURE Machine for attaching articles, such as buttons, to workpieces in a simple and automatically controlled manner, at high speed and with uniform results. The machine operates automatically through a predetermined cycle for applying a certain number of stitches to attach a button or the like to a workpiece, after which the stitching is stopped. Means are then provided for opening the button holding or clamping means and for severing the thread at a point close to the last stitch provided. Also means are provided for then lifting the holding or clamping means away from the work to permit the ready removal of the latter from the machine or the shifting of the work to a position in which another button or the like may be applied thereto. Various features enter into the control over the operation of the machine to insure its uniform performance in attaching buttons or the like to a succession of workpieces with a minimum effort on the part of the operator and at a high speed. In attaining the foregoing results a lever is rocked, either automatically or by means manually operated upon the completion of a predetermined number of stitches for the attachment of the article to the work, and this lever first opens the clamp to release the button and substantially simulaneously severs the thread adjacent the stitching region, at a sufiicient distance from the eye of the thread carrying needle to leave the latter ready for another operation, and then the clamp is lifted away from the work to facilitate preparation for another article attaching operation.

This invention relates to sewing machines of the groupstitch type adapted for use in the attachment of articles, such as buttons, to garments or fabrics intended for the production of garments.

It is a primary object of the invention to provide a machine of the foregoing character which is automatically controlled in the performance of the stitching of successive articles, such as buttons, snap fasteners, hooks and eyes, or the like, to fabrics, so as to insure uniform results and also high speed achievement of those results. Toward this end the machine is provided with conventional button clamping and holding means adapted to be rocked from an upward position into a downward position wherein it holds the button against the workpiece during the stitching operation. Upon the completion of each group-stitching operation, the clamping means is released and either automatically or manually lifted, by suitable means, away from the work. The lifting means includes a rockable arm or lever which is brought into operation upon the completion of a particular group of stitches which serve to attach a button or the like to the workpiece. The operation of the rockable arm or lever and the means for rocking it are such as to first open the jaws of the clamping means and also to sever the stitching thread at a suitable distance from the needle which carries it, before the clamping means is lifted away from the work.

In a semi-automatic machine, the arm or lever may be rocked by suitable connections from a treadle or knee press or any other manually operable member. The automatic performance of the three above-mentioned functions is brought about through a simple mechanism which is relatively light in weight and is readily operated without the production of undue vibrations or noise. Furthermore, it prepares the machine for the reception of a new workpiece and a new article to be attached to the workpiece, or the reception of a new article for application to the same workpiece involved in the just completed operation. The severance of the stitching thread, in the manner explained, insures the production of uniform results. The arrangement is such that the severing of the thread takes place at a predetermined point in relation to the button or other article being attached and in relation to the stitch forming needle. This latter relationship is such that a free end of the thread is left projecting from the needle for performance of a similar group-stitching operation upon a next button or other article to be attached to a workpiece.

With the foregoing purposes and advantages of the invention in view, a preferred embodiment of the invention will now be described in detail in reference to the accompanying drawings in which:

FIG. 1 is a side elevational view, with certain parts broken away and shown in section, and other parts removed to more clearly illustrate certain elements that are normally concealed within the frame structure of the machine;

FIG. 2 is a plane view of the lower portion of the machine, with the upper portion of the frame and parts carried thereby broken away to more clearly illustrate certain parts in a lower portion of the frame;

FIG. 3 is a vertical sectional view through a portion of the machine taken along the line 3-3 of FIG. 1;

FIG. 4 is a view of the button clamping means of the machine as seen from the bottom;

FIG. ,5 is a detail View showing in elevation the thread cutting means provided;

FIG. 6 is a plan view of the parts shown in FIG. 5;

FIG. 7 is a vertical sectional view through the cutting elements, taken along the line 7-7 of FIG. 5; and

FIG. 8 is a view, partly in elevation and partly in longitudinal section through the machine.

The machine illustrated in the drawings as the one embodying the present invention is of the general character of that disclosed in the patent to Nelson No. 2,609,- 773 granted Sept. 9, 1952. It will be understood that this is merely an illustrative embodiment of a machine to which the present invention may be advantageously applied. The description of the machine to be hereafter provided will be simplified, since the operation of the various stitch forming and work feeding devices incorporated in the machine are disclosed in the Nelson patent and reference to that patent may be made for further details. In this connection it may also be stated that the Nelson patent shows the button clamping means of the herein illustrated machine, and the means for lifting the same from the workpiece at an appropriate time in the course of operation of the machine. As explained in the Nelson patent, the machine may suitably be adapted to perform a group of sixteen stitching operations for the attachment of a button having four openings therethrough to a workpiece.

Referring now to the drawings, the machine has an enclosing frame structure as best shown in FIG. 1, which includes a vertical standard 10 having a base portion 11 at its lower end for mounting on a suitable table. Extending horizontally from the vertical standard is a work supporting arm 12 which is adapted to cooperate with the button clamping means that serves to retain the work against the top surface of the arm 12. Above the latter, and extending outwardly from the vertical standard 10 of the frame is an overhanging arm 13 which at its outer end, i.e., at the right end in FIG. 1, has a head 14 in which is mounted a vertically reciprocatory needle bar 15 adapted to carry a needle 15a for movement through the openings provided in the button being attached to the work. It will be understood that suitable connections are provided from a main drive shaft 16 mounted in the base of the machine, said shaft being suitably connected by a belt (not shown) with a power source. Conventional means may be provided for connecting the drive shaft with means for operating the needle bar and cooperating stitch forming means, such as a looper 151) (FIG. 3) for performingthe desired stitching operations.

The shaft 16 carries an eccentric 17 adapted to rock a member 18 back and forth through a suitable are upon each revolution of the shaft 16. During stitch forming operations of the machine, the rocking of member 18 is idle and performs no function. However, upon the completion of the group stitching, which as explained above may involve sixteen revolutions of the drive shaft 16, the lower end of a member19 is shifted toward the left into the position shown in FIG. 1, so that its shoulder 19a is in the path of a laterally extending portion 18a of the rock member 18. At this time, the rocking of member 18 by the eccentric 17 will cause downward movement of member 19. The upper end of the latter is pivotally connected with one arm of a lever 20 which is rockable about a supporting pin or stud 21. The forwardly extending end 20a of lever 20 carries a downwardly extending rod 22, the lower end of which extends laterally and carries a roller 23 adapted to cooperate with the under surface of a hook-shaped rod 24 secured to clamping means 25. The latter may be of the same character as that disclosed in the above-mentioned Nelson patent. It may be adapted for rocking movements about a supporting element 26, carried by the main frame of the machine. Normally, the clamping member 25 is urged downwardly by a spring 27, but when the rod 22 is lifted upwardly and in turn lifts the rod 24 upwardly, this will rock the clamping member 25 about the axis of element 26 and will lift thebutton retaining portion of the clamping member away from the work.

As best shown in FIG. 4, the clamping member carries two pivotally mounted elements 25a and 251), these being pivotally, mounted on a plate 252, forming a part of the clamping member 25, by means of screw elements or bolts 25c and 25d, respectively. A U-shaped spring 25 having its free ends engaged in openings within the pivoted elements 25a and 25b, serves to urge the free ends of the latter toward each other, and thus produces a good gripping action upon a button having its shank or other portion positioned between the free ends of these elements.

The lower end of the bar 19 is normally retained in a position toward the right of that shown in FIG. 1, so that its shoulder 19a will be out of the path of the bent portion 18a of rock member 18. This is when the machine is in operation. On the other hand, when the machine is at rest the parts in question are in the positions indicated in FIG. 1. Upon the starting up of the machine, the lower end of bar 19 will be swung toward the right to carry the shoulder 19a out of the path of portion 18a. This is accomplished in the manner shown in the above-mentioned patent to Nelson. As there disclosed, the starting up of the machine by the operators action upon the foot treadle or knee press will bring about counter-clockwise rocking movement of a shaft (FIG. 1) to which is secured an arm 29. The lower end of the latter is pivotally connected with a link 28 the opposite end of which is pivotally connected with the lower portion of the bar 19. As disclosed in the Nelson patent, the stopping of the machine upon the completion of a particular group of stitches may take place at the end of a selected number of stitches. Normally in the stitching of four-hole buttons, the machine will be arranged to operate through sixteen stitching cycles, while in the attachment of a two-hole button to a workpiece, the machine will be adapted to stop upon the completion of eight stitching cycles. Of course, any desired number of stitches may be performed prior to the automatic stopping of the machine. When the selected number of stitches has been produced, the shaft 30 will be rocked in a clockwise direction (FIG. 1) to return the lower end of bar 19 into the position shown in FIG. 1 and thus place the shoulder 19a in the path of part 18a of the rock member 18. Accordingly, upon the next revolution of the main drive shaft 16, its eccentric 17 in rocking the member 18 will cause part 18a of the latter to engage shoulder 19a on bar 19 and urge this bar downwardly. This, in turn, will result in the counterclockwise rocking of the lever 20 about its pivot 21 and will cause the rod 22 to engage the rod 24 and lift it along with the clamping means 25. Such upward rocking of the clamping means will be preceded, however, by two other operations, namely the opening of button retaining members 25a and 25b and the severing of the needle thread. The means for accomplishing these two functions will now be explained.

The means for opening the clamping means upon the rocking of the lever 20 as a result of the downward movement of bar 19 will now be described. Secured to the lever 20 in the region of its pivotal axis 21, to form a T- shaped lever, is a downwardly extending arm 31. This extends into the region of the pivotal support 26 of the member 25. At its lower end, the arm 31 has secured thereto an adjustable member 32. The latter is referably made adjustable in a vertical direction (FIG. 1) so as to position it in a desirable relation to a cooperating member 33 secured to a slidable rod 34. As the arm 31 swings in a counterclockwise direction, due to the downward pull on the bar 19, the member 32 will engage the member 33 and urge this toward the right (FIG. 1). This causes movement of the rod 34 toward the right so that its right end, which is connected by a member 35a and a screw 35b with an arm of a two-arm lever 35c, serves to rock this lever in a counterclockwise direction (FIG. 2) about a screw 35d. As there shown, the two-arm lever 356, to which the rod 34 is connected by means of member 35a, is arranged for pivotal movement around the axis of the screw 3511. The other arm of the two-arm lever cooperates with a screw 36 having threaded engagement with a plate 37 (FIGS. 2 and 4). If desired, the screw 36 may be provided with a shoulder engaging the top of plate 37 and with a lock nut 36a below the plate 37, to retain the screw firmly attached to the plate. A key element 370, rigidly connected with the plate 37, is slidably mounted in a groove 25k formed in the member 25s of the clamping means. The normal position of the plate 37 is made adjustable by means of as wingable arm 38 (FIG. 2). This swingable arm is pivotally connected to the plate 25e by means of the same screw 35d about which the lever 250 is rocked. Adjacent its free end (FIG. 2) the arm 38 is provided with an arcuate slot 38b which has a screw 38c extending therethrough and connected to the plate 25c. By loosening the screw 380 the arm 38 may be shifted toward the left or right (FIG. 2) so that its lefthand edge, which is in the path of the screw 36, serves to determine the normal or at rest position of the latter. This in turn determines the normal position of the clamping arm control plate 37. The adjustment is such as to control the normal or closed position of the two clamping arms 25a and 25b. Considering the construction as shown in FIGS. 2 and 4, it Will be apparent that when the lever 350 is rocked in a counterclockwise direction (FIG. 2), and thus shifts the screw .36 and the plate 37 toward the left, the slots 37a and 37b of plate 37, cooperating with screw elements 25h and 25 secured, respectively, to the clamping arms 25a and 25b will urge the free ends of the latter outwardly away from each other, and thus open the clamp jaws.

In connection with the foregoing, it is to be noted that the rocking of the two-arm lever 350 by the action of the member 32 carried by arm 31 against the member 33 carried by the rod 34 will continue until the clamp arms 25a and 25b are disengaged from the button that has been sewn onto the fabric. By appropriate adjustment of the parts this will take place before the rod 22, acting upon rod 24, will lift the clamping member away from the work during the last cycle of operation of the machine in applying a button or the like to a work piece. Such lifting of the clamping member will carry the member 33 out of engagement with the member 32 and allow the spring 25 (FIG. 4) of the clamping unit to restore the parts of the latter to their normal position. To eliminate the noise and shock incident to the sudden disengagement of the member 32 from the member 33, a compression spring 34a is preferably provided around the rod 34 to absorb the shock of the sudden return of the member 33 toward the left (FIG. 1).

Turning now to the needle thread cutting mechanism which is operated during the initial swinging of the lever 20 by the downward pull on bar 19, attention is directed particularly to the showings in FIGS. 1, 2, 3, and 6. It involves a link 40 of L-shaped form having its vertical portion adjustably secured to the arm 31 which is connected, as previously explained, to the lever 20. A special form of connection, which is best shown in FIG. 3, is provided for connecting the upper end of link 40 to the arm 31. This includes a head bolt 41 having a threaded stem 41a which at its opposite sides is milled flat in a conventional manner, so that the stem fits slidingly into a slot 31a (FIG. 1) extending lengthwise of the arm 31. At its free end the stem 41a of the bolt has a reduced diameter bearing portion 41b (FIG. 3). This is what receives, in bearing relation, the upper end of the link 40. An internal thread 41c is provided in the axial bore extending through the bolt 41. Within this bore is mounted a screw 41d which serves to retain the link 40 on the bear ing portion 41b of the bolt. A washer 41 is provided at the left side (FIG. 3) of the arm 31, and outwardly, i.e., toward the left, of this the portion 41a receives a nut 41g for retaining the bolt in desired adjustable position in relation to the opening 31a extending through the arm 31.

To the right end of the horizontally extending portion of the link 40 (FIG. 1) is adjustably connected a link 42. This is retained by screws 43 passing through elongated openings 40a in the link 40 and threaded into round openings in the link 42. Some adjustment of the length of the overall linkage is made possible in this manner. At its right end, the link 42 is connected with a slide bar 44. This connection is effected by a screw 44a. The slide bar is adapted for horizontal movement by the cooperation of openings 44b, extending through the bar, with screws 44c threaded into openings in the arms 12 of the frame of the sewing machine. The slide bar 44 has a horizontally extending cam portion 44d intermediate its ends, as best shown in FIG. 2. It is the movement of this cam portion of the slide bar through the connections from the arm 31 that brings about the relative movement of cutting blades which will now be described.

The thread cutting mechanism comprises a lower cutting blade 45 and an upper cutting blade 46. These have, respectively, upwardly extending pins 45a and 46a. The latter cooperate with slots 44e (FIG. 2) which are illclined toward each other. It will be apparent that as the member 44 is shifted toward the right in FIG. 2, the pins 45a and 46a will be drawn toward each other, and when the member 44 is restored toward the left into the position shown in FIG. 2, the pins 45a and 46a will be moved away from each other. Corresponding movements will be imparted to the cutting blades 45 and 46.

As best shown in FIGS. 5, 6 and 7, the lower blade 45 has secured thereto a vertically disposed member 45b. The latter is secured to blade 45 by screws 450, which are passed through openings in a horizontally extending portion 45d of the member. As best shown in FIG. 5, the main, vertically disposed portion of member 45b has its right end extending upwardly in a manner that serves to divide the cutting edge 45e of the lower cutting member 45 into two parts of about equal length (see FIG. 6). In this way the upwardly extending end portion of the member 45b, which is directly below the position of pin 46a, when the parts are in the position shown in FIGS. 5 and 6, and it is adapted to pass between the shanks S-1 and S2 of the needle thread loop when the blades 45 and46 are shifted to perform their cutting action. Thus, it will be apparent that when the two pins 45a and 46a are drawn toward each other by the action of the slots 442, the upwardly projecting portion of the blade 45b passes'b'etween the shanks S1 and S2 of the thread loop and holds them apart. Then when the cutting edge 46b of the upper knife is brought against the thread portions S1 and S2 and carries them toward the left (FIG. 6) and the cutting edge 45e of knife 45 is then moving toward the right (FIG. 6), the shank Sl which leads to the material will be placed adjacent the edge 45a to be cut, while the shank S2 which leads to the needle will be shifted into a clearance cut 45] of the blade 45. By virtue of this arrangement only the thread shank S1 leading to the material will be severed while the other thread shank S2 will not be severed. This insures that enough thread will be left in the needle to begin a new stitching cycle without the necessity of rethreading the needle.

It is believed clear from the foregoing that the illustrative machine disclosed herein is adapted to carry out automatically a selected series of stitching cycles, such as eight or sixteen, usually desired for the attachment of two-hole and four-hole buttons, respectively. Any conventional means may be employed for applying a button to the clamping means prior to the commencement of each series of stitching operations. This may be done manually, if desired. The operator then sets the machine into operation, as by means of a knee press, a foot treadle or the like, and the machine then carries out the eight or sixteen stitching cycles desired for the attachment of the particular button to a workpiece. Relative movement between the button and the path of reciprocation of the needle takes place, from one cycle to another, to cause the needle to pass through different holes in the button. It will be understood that a looper or the like acts upon the thread loop created upon the upward movement of the needle as it is engaged with the work, so as to produce the desired type of seam. During the last cycle of operation of the machine, it is automatically conditioned and controlled to bring about the release of the button from the clamping means, the automatic severing of the thread in a region just below the fabric to which the button has been applied, and the lifting of the clamping means to enable the removal or other shifting of the workpiece. As has been explained, the clipping of the thread is of such a character as to bring about severance of only one shank of a loop of thread created in the stitching operation. As a result of this, the other shank of the loop of thread will remain in the eye of the needle, so that the machine is ready for the performance of another stitching operation for the attachment of another button or the like to either the same workpiece or to a new workpiece.

As shown in FIG. 8, the illustrative machine is provided with starting and stopping means of the character disclosed in the above-mentioned Nelson Pat. No. 2,609,773. It involves an arm 50 secured to the rock shaft 30 and having connected therewith a downwardly extending rod 51 by which the arm 50 may be pulled downwardly by connections with a foot treadle or the like. This results in the clockwise shifting of a member 52 which has a lug 53 at its left end which is normally engaged with a groove in a member 54 carried by a disk 55 secured to the main drive shaft 16 of the machine. Also carried by, or connected with, the member 52 is an arm 56, the free end of which is provided with a cam ming surface adapted to operate a friction clutch which serves to connect the shaft of the machine with a power driven pulley 57. Thus, the main drive shaft of the machine willv be placed into operation by the rocking of the arm 50 and .member 52 in a clockwise direction. As disclosed in said Nelson patent, and aswill be hereinafter explained, the member 52 will be retained in its activated position for a predetermined number of revolutions of the main drive shaft of the machine, for example sixteen revolutions, to bring about the sixteen stitching operations desired for the attachment of a four-hole button or the like to a workpiece. Upon completion of the predetermined number of stitching operations a spring 58 will be enabled to rock the member 52 counterclockwise into its initial or normal position and thus stop the operation of the machine. This is made possible by the provision of a cam shaft 60 which is driven, by connections of the type shown in the Nelson patent, at the rate of one revolution for, say, sixteen revolutions of the main drive shaft. Secured to the cam shaft 60 is a disk 61, which has in its periphery a notch 61a. Cooperating with that notch is a pin 62 carried by an arm 63 clamped, or otherwise secured, to the shaft 30. It will be seen that when the disk 61 begins to rotate, as a result of the operation of the lever 50, the pin 62 will be held outwardly in the position into which it has been shifted by the rocking of the shaft 30. This brings about the shifting of the link or bar 19'toward the right (FIG. 1), and the shaft 30 will remain in this rocked position until the disk 61 completes a revolution and brings the notch 61a back into alignment with the pin 62. When this occurs, the spring 58 will bring about disengagement of the clutch and the stopping of the machine. It should be understood that this control over the operation of the sewing machine may be adapted to bring about stopping of the operation of the machine after any predetermined number of cycles of operation, as required for the attachment of a particular article to a workpiece.

The machine as shown in the drawings, and as de scribed above, is adapted for full automatic control over the operation of the machine, after it is oncestarted by the operator, to carry out the stitching operations required for attaching a button or the like to a workpiece, and for then automatically opening the clamping means, severing the stitching thread, and lifting the clamping means away from the workpiece, thereby placing the machine in condition for another cycle of operations to be initiated by the operator. However, certain novel features of the invention are adapted to be used advantageously in connection with a semi-automatically controlled machine. Such a machine may, for example, be adapted to carry out automatically a particular number of stitch forming operations for the attachment of a button or the like to a workpiece, and when this cycle of opera tions has been completed the machine will come to a stop. The operator may then bring about the clamp opening, thread severing and clamp lifting operations manually, as by connections from a foot treadle or knee press or the like. The illustrated machine may be very readily adapted for such semi-automatic operation by simply shifting the link 28 (FIG. 1) from the position there shown into a position in which its left end is pivotally connected by means of a screw 28a with the opening 28b at the lower end of the arm 29. When this is done, the lower end of bar 19 will be swung toward the right to a certain extent, so that the shoulder 19a thereon will always be out of the path of movement of the bent portion 18a of the rock member 18. Therefore, the downward pulling of the bar 19 to bring about rocking of the lever 20 will not take place automatically at any time through the operation of the rock member 18. Instead suitable connections will be provided from a treadle, knee press or the like, by means of a rod or chain to an opening 19b at the lower end of the bar 19, to pull this downwardly. In this way the operator can bring about manual operation of the lever 20 with resultant opening of the clamp jaws, operation of the cutter blades 45 and 46 and the lifting of, the clamping means. In other respects the semi-automatic machine may be similar to the automatic machine shown in the drawings and described above.

While a preferred embodiment of the invention has been described in some detail, and certain variations have been mentioned, it will be understood that various other changes may be made in certain features or elements of the construction, within the scope of the invention.

What is claimed is:

1. A sewing machine adapted for the attachment of articles to workpieces which comprises a main drive shaft, stitch forming means including a reciprocatory thread carrying needle driven by said shaft, means for starting the operation of the machine, means driven by said shaft for controlling the stopping of the machine after a predetermined number of stitches have been produced, clamping means for retaining an article to be attached to a workpiece in the region in which said stitch forming means operates, thread cutter means for severing the stitching thread in the region of stitch formation, and a rockable member adapted for operation upon the com pletion of the predetermined number of stitch s for causing the clamping means to release the article that has been attached to the workpiece, substantially simultaneously operating said cutter means for severing the thread, and for thereafter lifting the clamping means away from the workpiece to enable free shifting of the latter.

2. A sewing machine adapted for the attachment of articles to workpieces which comprises a main drive shaft, stitch forming means including a reciprocatory thread carrying needle driven by said shaft, means for starting the operation of the machine, means driven by said shaft for controlling the stopping of the machine after a predetermined number of stitches have been produced, clamping means for retaining an article to be attached to a workpiece in the region in which said stitch forming means operates, thread cutter means for severing the stitching thread in the region of stitch formation, means associated with the cutter means for insuring separation of the shanks of the loop of thread created upon upward movement of the needle, to enable severing of the shank extending downwardly from the work but not the shank extending upwardly to the needle, and means adapted for operation upon the completion of the predetermined number of stitches for causing the clamping means to release the article that has been attached to the workpiece, substantially simultaneously operating said cutter means for severing the thread, and for thereafter lifting the clamping means away from the workpiece to enable free shifting of the latter.

3. In a sewing machine as set forth in claim 2 said thread cutter means comprising a pair of flat blades mounted below the work supporting surface of the machine, and means for shifting at least one of said blades relative to the other to sever the shank of thread extending downwardly from the work.

4. In a sewing machine as set forth in claim 3, said last recited means shifting one of said blades in one direction and the other of said blades in the opposite direction to effect the severing of the thread.

5. In a sewing machine as set forth in claim 1, said clamping means having members at opposite sides of the article to be attached to the workpieces which members are spring urged toward each other and said article, and adjustable means for limiting the extent of movement of said members of said clamping means toward each other.

6. In a sewing machine as set forth in claim 5, said means for releasing the article from said clamping members comprising camming means for urging said members away from the article being attached to a workpiece.

7. In a sewing machine as set forth in claim 6, means for controlling the gripping and releasing actions of said clamping members which comprises a shiftable control element adapted to cam said members toward and away from each other, and means for limiting the extent of movement of said members toward each other.

8. In a sewing machine as set forth in claim 1, said member adapted for operation upon the completion of the predetermined number of stitches being automatically operated upon such completion.

9. In a sewing machine as set forth in claim 8, said .clamping means having swingable arms at opposite sides of the article to be attached to the workpieces, spring means normally urging said arms toward each other to cause portions thereof to grip the article, cam means cooperating with said arms adapted to swing them away from each other, and adjustable means for limiting the extent to which said arms are swung toward each other by said spring means.

10. In a sewing machine as set forth in claim 9, said cam means being a slotted plate arranged to be shifted longitudinally of said swingable arms, said arms carrying elements cooperating with slots in said plate to thereby cause swinging movem nt of said arms.

11. In a sewing machine as set forth in claim 8, said member operable automatically upon completion of a predetermined number of stitching operations comprising a multiple-armed lever rockable about a fixed pivot, one arm of said lever having pivotally connected therewith a rod, an oscillatable member, connections from said main drive shaft for oscillating said oscillatable member upon each revolution of said shaft, said rod and said oscillatable member having shoulders adapted to be shifted into and out of cooperative relation upon completion of a predetermined number of stitches, thereby causing rocking of said lever, and connections from said lever for causing the release of said clamping means, the actuation of said cutter means to sever the thread, and then the lifting of said clamping means away from the Work.

12. In a sewing machine as set forth in claim 11, said lever 'being T-shaped and having a vertically disposed central arm and upper arms extending in opposite directions from said central arm, connections from the lower portion of said central arm for causing the release of said clamping means and the actuation of said cutter means.

13. In a sewing machine as set forth in claim 12, one of said upper arms having connected therewith a hooked rod arranged to cooperate with a hooked rod carried by said clamping means, said hooked rods being so constructed and arranged that upward movement of said first-mentioned hooked rod will not be imparted to said second-mentioned hooked rod until after the release of said clamping means and the actuation of said cutter means.

14. In a sewing machine as set forth in claim 11, said means for causing the release of said clamping means comprising a block adjustably mounted on said central arm of said lever and a block carried by a slidable member mounted on said clamping means, said blocks being disengaged upon the lifting of the clamping means from the work, thereby restoring the clamping means to active condition and enabling the introduction of a new article into said clamping means.

15. In a sewing machine as set forth in claim 11, said cutter means comprising a pair of relatively slidable blades extending in a direction parallel with the axis about which said lever rocks, said means for operating said cutter means comprising a slide member having camming slots cooperating with pins carried by said blades, and connections from the downwardly extending arm of said lever for operating said slide member.

16. In a sewing machine as set forth in claim 14, means carried by one of said cutter blades shiftable by the movement of said one of said cutter blades between the shanks of a thread loop created upon upward movement of the needle, thereby retaining only one of said shanks in the path of cutting edges on said blades.

17. A sewing machine as set forth in claim 8 in which said rockable member comprises a T-shaped lever, connections from said drive shaft for rocking said lever upon completion of a predetermined number of rotations of said shaft, and connections from said T-shaped lever for substantially simultaneously opening said clamping means and operating said cutter means and thereafter lifting the clamping means.

18. A sewing machine as set forth in claim 1, in which said means for starting the operation of the machine is manually operable, said means driven by said main drive shaft serving to retain said machine in operation until a predetermined number of stitches have been produced.

19. In a sewing machine as set forth in claim 8, adjust able means for varying the point in a cycle of operation of the machine at which the clamping means releases the article.

20. In a sewing machine as set forth in claim 8, adjustable means for varying the point in a cycle of operation of the machine at which the clamping means is lifted away from the workpiece.

21. A sewing machine as set forth in claim 8, in which said connections from said rockable member for opening said clamping means comprises a slidable rod, means carried by said rockable member and said rod which are brought into engagement upon the rocking of said member, thereby causing shifting of said rod, and a cam member operated by said rod and cooperating with said clamping means for opening the latter.

22. A sewing machine as set forth in claim 8, in which said means automatically operable upon completion of the predetermined number of stitches comprises a multiple-armed lever having an arm extending downwardly from its pivot point, and connections from said arm to said cutter means for operating the latter, said connections including an L-shaped link pivotally connected at one end with said arm and at its other end with a slidable cam, said cam cooperating with said cutter for operating the same.

23. In a sewing machine as set forth in claim 22, said cutter having a pair of horizontally disposed blades, said slidable cam extending horizontally in a direction parallel with said cutter blades.

24. In a sewing machine as set forth in claim 23, said cam having slots therein cooperating with projections on said blades for shifting the latter longitudinally in relation to each other.

25. A sewing machine as set forth in claim 1 in which said member adapted for operation upon the completion of the predetermined number of stitches comprises a T- shaped rockable lever, connections being provided from said lever for substantially simultaneously opening said clamping means and operating said cutter means and thereafter lifting the clamping means.

26. A sewing machine as set forth in claim 25 in which said connections from said rockable lever for opening said clamping means comprises a slidable rod, means carried by said rockable lever and said slidable rod which are brought into engagement upon the rocking of said lever, thereby causing shifting of said rod, and a cam member operated by said rod cooperating with said clamping means for opening the latter.

References Cited UNITED STATES PATENTS 2,509,619 5/ 1950 Vollman 112-110 2,609,773 9/1952 Nelson 1l2-110 X 2,645,192 7/1953 McCahn 112-110 2,781,734 2/1957 Maxant et a1 1121 14 FOREIGN PATENTS 1,037,824 8/1958 Germany.

MERVIN STEIN, Primary Examiner G. V. LARKIN, Assistant Examiner US. Cl. X.R. 112252

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