US3318274A - Take-up mechanism and drive mechanism for sewing machines - Google Patents

Description

E. SCHOLJ May 9, 1967 TAKE-UP MECHANISM AND DRIVE MECHANISM FOR SEWING MACHINES 8 Sheets-Sheet 1 Filed March 5, 1964 wm mm wm um w v m v NM mm mm Ev $CHOIJ May 9, 1967 TAKE-UP MECHANISM AND DRIVE MECHANISM FOR SEWING MACHINES Filed March 5, 1964 8 Sheets-Sheet 2 mm GNm 3 m mm M ow 3 mm c n Mm mm a E. SCHOIJ May 9, 1967 TAKE'UP MECHANISM AND DRIVE MECHANISM FOR SEWING MACHINES 8 Sheets-Sheet 3 Filed March 5, 1964 E. SCHOIJ May 9, 1967 TAKE-UP MECHANISM AND DRIVE MECHANISM FOR SEWING MACHINES Filed March 5, 1964 8 Sheets-Sheet 4 a; d a;

[HlIIll E. SCHCJEJ May 9, 1967 TAKE'UP MECHANISM AND DRIVE MECHANISM FOR SEWING MACHINES 8 Sheets-Sheet 5 Filed March 5, 1964 P; E. SCHOiJ BMQM TAKE-UP MECHANISM AND DRIVE MECHANISM FOR SEWING MACHINES May 9, 1967 8 Sheets-Sheet 6 Filed March .5, 1964 y 1967 E. see-mm 3,318,114

TAKEUP MECHANISM AND DRIVE MECHANISM FOR SEWING MACHlNES Filed March L), 1964. 8 Sheets-Sheet 7' E. SCHOU 3,3i8,274

WING MACHINES May 9, 1967 TAKE-UP MECHANISM AND DRIVE MECHANISM FOR SE 8 Sheets-Sheet 8 Filed March .5, 1964 NWO;

INVENTOR U o H C S R A G D E United States Patent nois Filed Mar. 5, 1964, Ser. No. 349,702 24 Claims. (Cl. 112-248) This invention relates to novel needle-thread takeup mechanism and balanced drive mechanism from the main drive shaft of a high speed, industrial sewing machine. It is particularly concerned with such machines adapted to produce a lockstitch seam involving the cooperation of a rotary hook with a reciprocatory needle. However certain features of the invention are applicable to other types of industrial sewing machines.

The improved take-up mechanism involves a thread engaging and shifting finger or the like which is moved through an elliptical or oval .path upon each revolution of the main drive shaft of the machine. The arrangement is such that the finger which is moved through an elliptical path is advanced at different linear speeds in different portions of the path of movement. This enables the finger to exert a pull upon the thread and a release of any pulling force upon the thread at the particular times and at desirable speeds in a cycle of operation of the machine in which these actions are to be performed. By virtue of the particular construction contemplated by the invention, the danger of entanglement of the thread with moving parts of the mechanism of the machine is prevented, and the take-up action is smoothly imparted to the thread so that the danger of thread breakage due to the application of a take-up force is reduced to a minimum.

It has been found that to achieve the purposes of the invention most effectively, it is desirable to bring about movement of the thread engaging element along an elliptical path having its major axis disposed at a substantial angle to both the vertical and the horizontal, and preferably at an angle of about 38 degrees to the horizontal. To bring about the desired path and variation in speed of movement of the take-up finger, the preferred embodiment of the invention provides the takeup finger at the end of an arm which is swung, i.e. rotated, about an axis adjacent the other end thereof that is reciprocated in a vertical direction to a substantial extent during each cycle of operation of the machine. Thus the thread engaging element is given a compound move-ment which is a combination of the rotary swinging of its carrying arm about an aXis adjacent the remote end of the arm, and of the bodily reciprocato-ry movement of that axis along a straight line. In a preferred form of the invention, as applied to a lockstitch machine, the major axis of the elliptical path is approximately 1 /2 times the minor axis of such path.

The timing of the thread engaging element, i.e. its rate of movement, in the various portions of the elliptical path is such as to meet the requirements of the stitch forming elements for the needle thread, and the need for imparting a pulling force to such thread for stitch setting purposes and for pull-off of the thread from the source of supply.

3,318,274 Patented May 9, 1967 "ice The improved balancing forces and vibration reducing forces imparted to certain parts of the driving mechanism is such as to offset forces created by the reversal of movement of reciprocating parts of the mechanism, as well as the change in speed of movement of the takeup element in the movement of the latter along an elliptical path. To achieve these purposes the invention contemplates a predetermined relationship between certain counterbalancing elements and between these and other parts of the mechanism.

A further feature of the present invention is the provision of means for quickly removing sections of thread, that may be caught within the frame, whenever a breakage of the thread happens to occur in the course of operation of the machine. This aspect of the invention involves the provision of means for preventing the thread from becoming wrapped about a moving element within the machine frame which would tend to accumulate an excessive amount of thread upon its breakage in the course of operation of the machine. The arrangement is such that any thread tending to wrap itself around any element within the machine frame, upon breakage of the thread, will become wrapped about two normally stationary elements. One of these is carried by an outwardly swingable cover plate, while the other is secured in fixed position and is provided with a cutting blade which is normally completely out of the path of the thread. When a section of the thread wraps around the two elements referred to, the outward swinging of the cover carrying the first mentioned element will automatically bring about the shearing of the loops of thread so wrapped. The first mentioned element, moreover, serves as a guide for the thread during certain portions of each cycle of operation of the machine. This is due to its relationship to certain fixed thread guiding elements and the take-up element discussed above. To insure proper operation of the first mentioned element, this is preferably mounted adjustably on the swingable cover member.

In accordance with the invention special means are provided for removing the tension normally applied to the needle thread whenever it is desired to remove completed work from the machine. This contributes toward the high speed operation of the machine as a whole.

Other features and advantages of the invention will appear from the detailed description of a preferred embodiment of the same which will now be given in conjunction with the accompanying drawings in which:

FIG. 1 is a vertical sectional view taken longitudinally through the head portion of the overhanging arm of a sewing machine embodying the invention;

FIG. 2 is a side elevational view, partly in section, of a portion of the frame and the end closure member for the head, said closure member being swung outwardly from the position shown in FIG. 1;

FIG. 3 is a detail view in vertical section along the line 3-3 of FIG. 1;

FIG. 4 is a view, partly in elevation and partly in vertical section, of the end of the head of the frame, showing certain parts within the latter;

FIG. 5 is an end view of the head of the machine, in vertical elevation, showing certain parts connected therewith;

FIG. 6 is an enlarged detail view of members carried by the head of the frame, as seen from the left in FIG.

FIG. 7 is a detail view of a bracket member and related parts taken along the line 7-7 of FIG. 6;

FIG. 8 is a detail view of certain parts taken along the line H of FIG. 7;

FIG. 9 is a perspective view of a bracket member shown in elevation in FIGS. 6 and 7;

FIG. 10 is a perspective view of a rock member shown in FIG. 7;

FIG. 11 is an elevational view of the inner face of the end cover plate for the head portion of the upper arm of the frame;

FIG. 12 is a cross-sectional view taken along the line 1212 of FIG. 11;

FIG. 13 is an elevational view of a part secured tothe head of the frame of the machine just inside of the cover member shown in FIG. 11;

FIG. 14 is a side elevational view of the member shown in FIG. 13, as seen from the right of FIG. 13;

FIG. 15 is a diagrammatic view showing the path of movement of the take-up finger of the invention, the spacing of the dots indicating the distance through which the finger travels in the direction of the arrow for each 10 of rotation of the main drive shaft of the machine;

FIG. 16 is an exploded perspective view of parts in the connections'from the main drive shaft to the take-up finger;

FIGS. 17 through 21 are views, taken from the left end of the head of the machine as shown in FIG. 1, illustrating a number of different positions assumed by the-take-up finger, the needle and a rotary hook during a revolution of the main shaft; and

FIG. 22 is a bottom plan view of the machine with a bottom plate removed.

Referring now to the above-mentioned dra-wings, these show thefeatures of the present invention applied to a lockstitch sewing machine of the general character of that disclosed in the US. patent to Covert No. 2,977,910, granted Apr. 4, 1961. It comprises a frame having an overhanging arm .10 terminating in a head portion 11 (FIG. 1). Beneath the overhanging arm is a base portion, of which only that part which is below the head portion 11 of the arrnis indicated at 12 in FIGS. 17-2'1 inclusive. Extending longitudinally of the overhanging arm is a main drive. shaft 13 which, as will be understood, is adapted to be driven through a pulley and handwheel mounted thereon adjacent its right end (not shown). This shaft is journ alled in suitable bearings carried by the frame, including a bearing 14 (FIG; 1) adjacent the left end of the shaft. An extension 15 secured to the left end of the shaft extends into the head portion 11 of the arm.

' [Asbest shown in FIGS. 1, ,3 and 16 the extension 15 i of shaft '13, is provided with a cut away region 16 adapted to accommodate apinion 17 and related parts. Pinion 17 has a hub extension'17a by which the pinion may be secured through set screws to a shaft 18. This shaft is journalled at its" right end (FIG. 1) in a roller or needle 7 bearing-unit 19 carried by extensionlS, and is journ-alled 'toward its .left end in'a-ball bearingmember 20 carried by .the extension .15; Pinion- 17 meshes with an internal gear ring 21'secured by screws 21a to an. annular member 22 fixedly mounted Within the head portion of the overhanging arm. to. retain the-member 21 in fixed position.

Pins 21b cooperating with alined openings in members '21 and 22 serve to insure proper mounting of member 21 in relation to the frame of the machine.

To the left of the ball bearing unit 20 there is secured to the shaft 18 a rotary crank member 23 having a; counterweight portion 23a. Crank arm 23 has secured thereto, adjacent its outer end, a pin 24 which cooperates with a roller or needle bearing unit 25 carried by a connecting link 26. The lower end of this link is connected by a screw stud 27 with an upwardly extending head portion of a reciprocatory needle bar 28. The latter is mounted for vertical reciprocation within bearing elements 29a in a sleeve 29 carried by the head portion 11 of the frame.

For applying a force to counterbalance that resulting from the reciprocation of the needle bar, that would otherwise produce objectionable vibrations, a horseshoeshaped counterweight member 30 is secured by screws 30a to a slightly enlarged portion 15a of shaft extension 15. For similar purposes a horseshoe-shaped counterweight member 31 is secured by screws to the face of the portion 23a of crank 23.

Now assuming that the shaft 13 and its extension 15 are rotated in a clockwise direction, as seen from the left in FIGS. 1 and 16, the arrangement above described will serve to carry the pinion 17 and its supporting shaft 18 in a clockwise direction. Meshing of the teeth of pinion 17 with the internal gear teeth of member 21 will cause the pinion 17 and its shaft 18 to rotate in a counterclockwise direction. As a result of the clockwise bodily movement of the pinion when the parts are in position as shown in FIGS. 1 and 16, the counterweight 30 has its center of mass above the axis of mainshaft 13. Therefore, it will be seen that in approaching this position, the counterweight30 tends to exert a force having a vertically upward component as the needle bar 28 approaches its lowermost position and as it begins its upward movement. When mainshaft 13 has been rotated through :an angle of 180 and pinion 17 has been correspondingly rotated in the opposite direction, the center of mass ofcounterweight 30 will be below the axis of shaft 13 so that a downward component of inertia force will be created as the needle bar approaches its'uppermost position and begins its movement downwardly.

When needle bar 28 is in either its highest position or lowest position, it exerts a maximum inertia force which is opposed by an equal and opposite inertia force created by counterweight 30 and certain parts associated therewith. As the needle bar moves toward the center of its stroke, its inertia force gradually diminishes until, at the center of its stroke, it is at its zero force. The inertia force of counterweight 30, when not in a strictly vertical direction has components in both a vertical and horizontal direction and for limited times only in a horizontal direction. The horizontal component of the inertia force created by counterweight 30 and associated parts would place the needle bar mechanism in a completely unbalanced condition if it were not for the equal and opposite horizontal component of the inertia force created by parts, including portion increasing and decreasing vertical component of the inertia force created by counterweight 30 and the parts associated therewith.- The gradual increasing and decreasing horizontal inertia force component of counterweight 30 is always opposed by the gradually changing horizontal inertia force of counterweight 31. Of course, when the needle bar '28 is at the'center of its stroke and at zero inertia force, counterweight 31 and associated parts is exerting a maximum horizontal inertia force that opposes the maximum horizontal inertia force of counterweight 30 and the parts associated therewith.

In connection with the foregoing it will be mentioned that the pitch diameter of pinion 17 is one half of the pitch diameter of the internal gear teeth of member 21. Also it should be mentioned that the construction is such that the axis of the pin 24 is at all times alined with the pitch circle of the pinion 17. This arrangement is such that the axis of pin 24 will partake of only a bodily reciprocatory movement, which is in a vertical plane passing through the axis of the needle bar 28 in a direction transverse to the direction of movement of the material being sewn.

As will be later described in detail, the present invention includes the provision of a thread take-up element 32 secured to the pin 24, this element carrying a take-up finger 32a. In the highly preferred construction of the overall combination it has been found desirable to so form the rigidly connected parts illustrated in the drawings as crank 23, 23a, counterweight 31, pin 24 and takeup element 32 with its finger 32a, that this assembly has its center of mass always located in a horizontal plane passing through the axis of shaft 13. When the needle is at the top or the bottom of its stroke, the center of mass of this assembly is positioned in axial alinement with the axis of the drive shaft 13. At other points in a cycle of operation of the machine, the center of mass mentioned moves horizontally in a plane passing through the axis of shaft 13. The end points of the motion of the center of mass within such horizontal plane are in horizontal alinement with the pitch circle of the internal gear 21. Thus the extent of horizontal movement of the specified center of mass is the same as the vertical movement of the needle bar. Also the total mass of the specified parts is preferably made equal to that of the needle bar and its connected parts, including the link 26, hearing 25 and the like. Since the inertia force involved in the movement of the specified assembly is at 90 to that involved in the reciprocation of the needle bar, a substantially uniform rotation imparting force is applied to the shaft 18 throughout the normal operation of the machine. This eliminates the production of torsional vibratory forces in the normal operation of the machine at any selected speed. The torsional forces required to rotate the shaft 13 are uniform at all constant speeds of rotation of said shaft. In connection with the foregoing it should be recognized that the pinion 17, and shaft 18 and related parts are not considered to be a part of the assembly tied to crank 23 referred to above, since these elements rotate with the shaft 13 and are counterbalanced by the construction of extension of that shaft and the counterweight 30.

By the foregoing construction it has been found possible to completely balance the vertical and horizontal shaking forces applied to the frame of the machine, and the torsional forces applied to the drive shaft 13, when the machine is operating at any selected speed. While certain specific devices, such as counterweights and the like, have been disclosed herein for achieving the purposes desired, it will be understood that other forms of mechanism may be used for bringing about the balancing of the various forces involved. This is particularly true With respect to the manner in which the assembly including crank 23 is constructed to insure the movement of its center of mass in a plane extending horizontally through the axis of the shaft 13.

Returning now to the description of the illustrated embodiment of the invention, secured to pin 24 is the take-up element 32. This has its main portion extending radially outwardly from the pin 24 in a direction at an angle to the longitudinal axis of the crank 23. The angle at which element or arm 32 extends, in relation to the longitudinal axis of the crank 23 may vary between 45 and 90, depending upon various aspects of the construction as a whole. As best shown in FIG. 4, in the embodiment herein illustrated the arm is inclined at an angle of about 60, or slightly more, to the longitudinal axis of the crank 23, in the direction in which the latter is turned about the axis of shaft 18 in the normal operation of the machine. At its outer end the arm 32 has a take-up finger 32a having its axis parallel with that of the pin 24. It will be apparent from the foregoing description that as the drive shaft 13 is rotated in a clockwise direction, and the shaft 18 is rotated in a counterclockwise direction, the take-up finger 32a will be given a compound movement as a result of the movement of pin 24 along a vertical path and the swinging of the arm 32 about the axis of the pin 24. The net result of this is to impart movement to the finger 32a along an elliptical or oval path. As shown in FIG. 15, this path is such that the elliptical path of the finger has its major axis inclined substantially to both the vertical and horizontal directions. In the preferred embodiment of the invention, the major axis of this path is inclined at an angle of about 38 to the horizontal. This may be varied within limits, if desired, but it has been found best for the purposes of the invention that said angle not exceed about 60 to the horizontal. Also it has been found best to have the form of the ellipse such that the length of its major axis is about 1.5 times that of its minor axis. As shown by the location of the dots in FIG. 15, which are indicative of the position of the finger 32a at each 10 interval in the rotation of the main drive shaft 13, that the distance through which the finger is moved during successive 10 intervals varies somewhat. In some areas its actual speed of linear movement is much greater than in other regions of the complete cycle. This is an important consideration in the proper functioning of the take-up finger in its take-up action on the needle thread and its movement away from the taken-up thread to avoid interference with the action of other mechanism in the machine in dealing with the needle thread. Thus in the application of the invention to a lockstitch sewing machine it is important that the take-up finger advance sufliciently rapidly during certain portions of a cycle of the machine to enable a loop of the needle thread to be passed around the bobbin case of a rotary hook employed in a lockstitch sewing machine. At the same time it is desirable to eliminate an excessive production of slack in the needle thread to avoid danger of its entanglement in the operation of the machine.

To insure retention of the needle thread in proper relation to the take-up finger 32a, and for various other purposes to be described, special closure means are provided for the end of the head 11. Such means include a plate 33 applied to the left end of the head 11 (FIG. 1), this plate having an opening 33a therethrough to permit the pin 24 to extend outwardly through the plate. Opening 33a, for this purpose, may simply be a relatively narrow one of rectangular form sufiicient to accommodate the vertical movement of the pin 24 between its upper and lower limits. Plate 33 is secured to head 11, along with an outer member 34, by means of screws 34a. Member 34 is provided with an opening 34b through its outer face of substantially the same elliptical contour as the path of movement of the finger 32a. A slight clearance is provided by forming this opening slightly larger than the path of the take-up finger. Within the opening 34b is provided a plate 35 of substantially the. same elliptical contour as the path of the take-up finger, with the outer periphery of this plate being spaced slightly inwardly of the path of movement of the finger at all points in the path of movement of the latter. is fixedly secured to the head of the arm by a bracket 36 which, as shown in FIG. 13, has its upper end welded or otherwise secured to an edge portion of the plate and has a downwardly extending part that is secured by screws 36a to the member 34. The upper portion of element 36 is provided with an offset 36b, as best shown in FIGS. 1 and 14. Extending downwardly into the space within this oifset is a knife blade or razor-like blade 37, the function of which will be described. The take-up finger 32a in its travel through the elliptical path will pass around the outer edge of the plate 35, and in a limited area will extend into the space Within the offset 36b.

A closure member 38 (FIGS. 1, 5 and 11) has downwardly extending leg portions 38a adapted for pivotal mounting on a small block 39 secured by screws 39a Plate 35 to the member 34. A pivot pin 39b serves to connect the cover plate with the block 39 for pivotal movement. Normally the cover plate is held in its closed position indicated in FIG. 1 by means of a spring latch cooperating with a pin 40a carried by member 34. Whenever desired the cover plate 38 may be swung outwardly about pin 39b to any desired extent. On its inner face the cover plate has an elliptical passage or groove 38b having a contour corresponding with the path of movement ofthe take-up finger 32a. A slight clearance is provided between the walls of the groove and the pin to avoid any direct contact between these parts. A narrow passage 380 is provided between the inner face of the cover plate 38 and the opposed surfaces of the member 34 and plate 35. This provides a space between the adjacent surfaces for the movement of the thread carried by the take-up finger in the course of its normal operation. Itwill be seen from the foregoing that the thread is well confined in the course of its movement in response to the action of the take-up'finger, so that there is no danger of its slipping off of the end of the finger or becoming entangled with any parts in the normal operation of the machine. Adjustably secured to the cover plate is a thread guide 41. This is secured to a plate 42 that is mounted for at least a limited amount of vertical adjustment by means of a screw 42a passing througha vertically elongated opening in the plate 42 and having threaded engagement, with the cover member 38. The inner end of thread guide 41 extends into an opening 35a in the late 35 when the cover is closed. To permit the adjustment of guide 41 the opening 35a and also the alined opening through the cover member are vertically elongated as shown in FIGS. 1 and 13. These openings are also such as to permit some sidewise adjustmentof the guide 41.

Referring now to FIGS. 17-21 inclusive, the relative positions of various parts is shown at different points in a cycle of operation of the machine. In these figures the needle thread is shown in broken lines at 43. It is delivered from a spool or cone (not shown) at the top of the machine downwardly along the rearward side of the frame to a guide member 44 having a suitable opening for the passage of the thread therethrough. From this point the thread extends downwardly to an adjustable I thread tensioning device 45. After passing through an t arcuate path between the'tensioning disks 45b of this de- 'vioe (see FIG. 6) the thread'is passed around a check spring member 46- forming a part, of the tensioning device and then downwardly to a fixed guide 47. From the latter the thread extends toward the front of the machine and upwardly around an adjustable guide 48, then over the take-up finger member 32a and lover to the adjustable fguide element .41.; From the latter the thread passes :about to be seized by the beak 51a of a notary hook 51.

It will be noted that at this time the take-up finger 32a is yielding some of the thread which it has previously.

carried 'upwardly. As disclosed in said Covert Patent No. 2,977,910, hereinabove mentioned, the rotary hookis driven at twice the angular speed of the main drive shaft, through connections of a conventional type shown In FIG. 18 the parts are shown at a slightly-later point in the cycle of rotation of the main drive shaft. The take-up finger has now been carried out of engagement with the needle thread so that the latter extends directly from the guide element 48 to guide element 41. At the same time the beak 51a of the looper is carrying a loop of the needle thread around the bobbin case of the looper, and this may result in pulling downwardly to a slight extent on the check spring 46, the thread thus being under a slight extra tension. As the parts reach the position shown in FIG. 19 the loop around the bobbin case is being released and the take-up finger 32a has engaged a portion of the thread to start the take-up action. Then proceeding to FIG. 20 it will be noted that the loop of thread has, been completely withdrawn from the rotary hook and is about to be set in the fabric being sewn. At this stage of the cycle the take-up finger 32a is performing a further take-up action on the thread and has removed it from contact with the guide element 41. Passing then to FIG. 21, it will be seen that the take-up finger 32a is in substantially its uppermost position. Just prior to reaching that position it will have served to draw a certain amount of thread from the source of supply to compensate for that used in the previous stitch formed and it will have drawn the check spring down to its lowermost position. After reaching the position of FIG. 21 the finger will no longer draw thread from the supply but will beginto create slack to a limited but" gradually increasing extent. At this stage of the operation the rotary hook is passing through its idle revolution in which it does not seize the needle thread and carry it around the bobbin case. This will have begun slightly before the take-up finger reaches the position shown in FIG. 20. By the time the parts arrive back at the position shown in FIG. 17 the same steps as described above will be repeated. The various notations applied to FIG. 15 will assist in understanding the timing of the action of the take-up finger as described above. In connection with the foregoing it will of course be understood that the rotary hook is driven at twice the angular speed of themain drive shaft so that only alternate revolutions of the hook are effective in seizing a needle thread loop to form a new stitch.

In FIG. 4 the presser foot arrangement-provided in the machine is shown. Thus a presser foot 52 adapted V to engage the upper surface of the work being stitched and-force the latter against the throat plate of the machine is connected bya screw 52a with the lower end of a largely tubular presser bar 53. The latter is mountedfor vertical sliding movement in a sleeve 54 carried by the head 11 of the frame. A spring 55 within the major portion of the presser bar serves to urge the latter and'the, presser foot downwardly under a desired pressure. At its upper end the spring engages an enlarged head of a rod 56 which is adapted for vertical adjustment to vary the force of spring 55 by the turning of a screw threaded member having a knurled head 57. will be apparent that the force of spring 55 may be reduced by turning the knob 57 to cause the pin 56 to rise slightly, and the pressure may be increased by turning the knob in the opposite direction, Work feeding mechanism of any desired form, such as that shown in the, above-mentioned Covert Patent No. 2,977,910, may

in FIG. 22. As shown in said figure, the main drive shaft'13 of the machine has secured thereto a pulley 51b which is connected by a belt 510 with a pulley 51d secured to a shaft 51e extending longitudinally .of

the base of theframe of the machine.

Shaft 51e has secured thereto a gear 51f which meshes with a pinion 51g secured to another shaftfSlh. The latter has secured thereto the rotary component of the rotary hook 51.

be used for advancing the work through the stitch forming zone.. 7

When the hook is to be removed from the machine the presser bar 53 may belifted by the operation .of a.

) mounted for rocking movement about a pin 61 carried by a bracket member 62 shown in perspective in FIG. 9. This bracket is secured by suitable screws to the frame of the machine. As the arm 60 is thus rocked upwardly it engages and lifts an arm 63 secured in any suitable way to the presser bar 53, thus lifting the presser foot away from the work against the action of spring 55.

Means are provided for eliminating the tension applied to the needle thread by the tensioning device 45 as the presser foot is lifted in the manner explained. It will be understood that this does not occur when the presser foot and bar are shifted upwardly in the course of operation of the machine due to variations in the thickness of the Work. The thread tensioning device 45 is provided with a spring 45a which normally urges the two disks 4517 into engagement with each other. The thread 43, as will be understood, passes between the disks 45b to have the desired tension applied thereto depending upon the force of spring 45a. This tension may be varied as desired by turning a knurled head 450 of a screw member to vary the amount of compressive force incorporated in the spring 45a.

To release the thread from the tension normally applied by the disks 45b when the presser foot is lifted by the action of element 59 in the manner explained, the member having arm 60 is provided with an oppositely extending arm 60a (FIGS. 7 and 10), the latter being rocked downwardly when the arm 60 is rocked upwardly. Downward rocking of arm 60a will cause it to engage a block 64 that is secured for vertical adjustment in relation to a slide member 65. The latter is mounted for vertical movement in a passage between arms 62a and 62b of bracket 62 (FIG. 9). Slide 65 is provided with a recess or indentation 65a (FIG. 6) which cooperates with a pin 45d incorporated in the thread tensioning device '45. As the slide 65 is forced downwardly by the downward rocking of arm 60a the inclined upper surface of the recess 65a will cause the pin 45d to be cammed toward the right and thus remove the force of spring 45a from the disks 45b in a manner well understood in the art. See Taylor Patent No. 3,099,236, granted July 30, 1963, for a suitable construction for the purpose. By so releasing the tension applied to the spring as the presser foot is manually raised in the manner explained, the removal of work from the machine along with a suflicient amount of needle thread to enable quick severance of the latter is brought about.

Means of the general character disclosed in the abovementioned Covert patent are provided for insuring proper lubrication of the various bearing surfaces at the forward end of the arm 10 and in the head 11. This includes a lubricant delivering tube 66, a reservoir 67 and tubing and other passages for conveying the lubricant to the surfaces requiring lubrication.

It is believed clear from the foregoing description and the accompanying drawings that a machine constructed in accordance with the present invention serves to retain the relatively large section of needle thread within the machine in a quite definite position at all times. Thus even when the needle thread is put into a somewhat slack condition it is nevertheless well confined within a particular region so as to eliminate the danger of entanglement of one part of this thread with another part and to prevent its entanglement with moving parts of the machine. It is guided and confined to a desired path by such elements as the plate 35, the take-up pin 32a, the inner face of the cover member 38 providing a relatively narrow passage 38c between it and the outer face of member 34 and the plate 35, and by several adjustable guide elements 44, 45, 46, 47, 48, 41 and 49. Moreover with the provision of the counterbalancing elements 30, 31 and 23a it is assured that the machine may be operated at exceptionally high speeds without the development of excessive noise and vibrations. Toward this end, the provision of various roller or needle bearing units and ball 10 bearing means eliminates wear and the development of excessive heat in the high speed operation of the machine.

While the improved thread take-up means employed reduces to a minimum the danger of thread breakage in the course of high speed operation, some thread breakage is bound to occur on occasion. When it does occur, the free end of the thread from the point of breakage, particularly when the thread is under tension at the time of breakage, which is the most likely time for its occurrence, will wrap itself around the guide element 41 and the closely adjacent portion of the bracket 36 which carries the razor blade or knife element 37. There is little or no danger of it becoming wrapped about a rapidly moving element such as the takeup finger 32a, because of the confinement of the path of the thread. However if it should become wrapped about this finger it will become rather quickly severed by the knife element 37. There is accordingly little or no tendency of the thread to continue to wrap about any elements of the structure if the machine is continued in operation for an appreciable time after the breakage occurs. The operator will of course quickly notice any thread breakage and will stop the machine as promptly as possible. Such thread as may have become wrapped around the guide 41 and knife blade 37, as shown in FIG. 2, may then be readily removed by simply opening the cover plate 38 outwardly, which will result in drawing the loops of thread across the cutting edge of knife 37 to enable quick removal of the accumulated thread.

Rethreading of the needle may be very simply and quickly accomplished due to the accessible location of the various guide elements and the provision of the passage 380 between the cover plate 38 and the member 34. This enables the thread to be passed very readily over the take-up finger 32a and the guide element 41.

While a preferred embodiment of the invention has been described and shown in some detail it will be understood that various changes may be made in the construction and arrangement of parts without departing from the invention as defined by the appended claims.

What is claimed is:

-1. In a sewing machine having a frame with an overhanging arm with a head portion at its outer end, a drive shaft journalled in said arm, a reciprocatory needle bar mounted in the head portion of said arm, a needle carried by said bar, complementary means cooperating with said needle for producing a multiple thread stitch, connections from said shaft for reciprocating said needle bar and operating said complementary means to form a line of stitching, means for directing thread to said needle, thread take-up means in the path of said thread for imparting a take-up action thereto, connections from said shaft for operating said thread take-up means, the combination which comprises a rotary member in at least one of said connections from said drive shaft to said needle bar, said complementary means and said thread take-up means, said rotary member being mounted for rotation in a direction opposite to that of said shafit about an axis removed from but parallel with the axis of said shaft, means carried by said drive shaft providing a first center of mass eccentric to the axis thereof, and means carried by said rotary member providing a second center of mass eccentric to the axis of rotation of said rotary member, said two mass providing means being so constructed and arranged that their combined inertia forces provide an active component along the line of movement of said needle bar and have components that are opposite to each other in a direction transverse to that of the movement of said needle bar.

2. In .a sewing machine as set forth in claim 1, said second mass providing means being so disposed that the maximum inertia forces involved in the rotation of said rotary member are substantially equal to the maximum inertia forces involved in the reciprocation of said needle bar and the connected parts reciprocated therewith, the two specified inertia forces operating at right angles to each other and so varying in magnitude as to provide a combined inertia force of equal magnitude in the regular operation of the machine.

3.'In a sewing machine as set forth in claim 1, said rotary member being in the connections from said drive shaft to said needle bar, and said rotary member. with parts rigidly connected therewith having the center of mass thereof arranged to reciprocate along a straight line through the same distance as the needle bar is reciprocated.

4. In a sewing machine as set forth in claim 2, the construction being such that the two specified inertia forces act along straight lines passing through the axis of the drive shaft.

5..In a sewing machine as set forth in claim 1, said thread take-up means having a thread engaging finger that is carried through an elliptical path upon each revolu- 7 tion of said drive shaft.

6. In a sewing machine as set forth in claim 5, the ellipticalv path of said thread take-up finger having its major axis inclined at not more than 60 to the horizontal.

7. In a sewing machine of the character set forth in claim 5, the elliptical path of said take-up finger having a major axis about 1.5 times the length of the minor axis thereof.

8. In a sewing machine of the character set forth in claim 3, the connections from said shaft which include said rotary member comprising a pinion carried by said i 1 driveshaft for orbital movement about the axis of the latter, said pinion being connected with said rotary member for rotation therewith, an internal gear fixedly connected with said frame, said pinion and gear having intermeshing teeth, .and said pinion having one-half the pitch f diameter of said gear.

9. In a sewing machine as set. forth in claim 8, said connections from said drive shaft to said needle bar comprising a crank element connected for rotation with said pinion, and a pin carried by said crank element having its axis alined with the pitch circle of said pinion.

10.'.In a sewing machine as set forth in claim 9', said ,t-hread take-up means having an arm integrally connected with said pin carried by said crank element and extending radially therefrom.

'11. In a sewing machine as set forth in claim 10, said thread take up means having a thread engaging finger extending'laterally from said arm in a direction parallel with said pin .jcarried by said crank element.

'12. In a sewing machine adapted to produce. a lockstitch, said machine comprising a frame having an overhanging arm with a head portion, a bar carrying a needle rnounted'for reciprocatory movement in said head, a rotary hook cooperating with said needle to form a lock-v stitch, a rotary drive shaft in said frame, and connections from said drive shaft for reciprocating said needle and rotating said rotaryhook, the combination which comprises a needle thread engaging finger adapted to impart a take-up action to said thread, connections from said drive shaft for operating said finger and imparting an elliptical path of movement thereto, said last mentioned connections comprising a second shaft parallel with but spaced from said drive shaft, a pinion secured to said second shaft, means connected with said drive shaft for carrying said second shaft in a circular path about the. axis of said drive shaft, an internal gear having twice the pitch diameter of said pinion fixedly secured to said frame in the region of said head portion of said arm, said pinion and gear having interengaging teeth, a crank arm secured to said second shaft for circular swinging movement about the axis of the latter, a pin extending from said crank arm parallel with said second shaft in alinement with the pitch circle of said pinion, and an arm extending radially from said pin from which said finger extends parallel with said pin in spaced relation to the latter.

13. In a sewing machine as set forth in claim 12, said second shaft being journalled in rotatable bearing means mounted in said means connected with said drive shaft for carrying said second shaft.

14. In a sewing machine as set forth in claim 12, said arm extending radially from said pin being directed therefrom in a direction between 45 and to the longitudinal axis of said crank arm in the direction in which said axis is advanced during operation of the machine.

15. In a sewing machine as set forth in claim 12, said arm extending radially from said pin being directed therefrom at such an angle to the longitudinal axis of said crank arm as to impart to said take-up finger an elliptical path of movement having its major axis inclined at least 30 to the vertical.

16. In a sewing machine as set forth in claim 12, said arm extending radially from said pin being directed therefrom at an angle of about 60 to the longitudinal axis of said crank arm.

17. In a sewing machine as set forth in claim 12, means carried by said head portion of the overhanging arm in a position rearwardly of and below the path of movement of said thread engaging finger for applying a frictional tensioning force to said thread, said last recited means comprising tension applying discs and a spring normally urging said discs together, a spring urged presser bar carrying a presser foot normally urged downwardly into engagement with the work being stitched, means operable at the will of the operator for lifting said presser foot away from the work, and connections from said last rectited means for offsetting the force of said spring which normally urges said tension applying discs together.

18. In a sewing machine adapted to produce a lockstitch, said machine comprising a frame having an overhanging arm with a head portion, a bar carrying a needle mounted for reciprocatory movement in said head, a rotary hook arranged to cooperate with said needle to form a lockstitch, a rotary drive shaft in said frame, and connections from said drive shaft for reciprocating said needle and rotating said rotary hook, the combination which comprises a needle thread engaging finger adapted to impart a take-up action to said thread, connections from said drive shaft for operating said finger and imparting an elliptical path of movement thereto, said last mentioned connections comprising an arm mounted for circular swinging movement about an axis parallel with that of said shaft, said finger being carried by the so-mounted arm and extending outwardly therefrom in a direction parallel with said axis, and means for shifting said axis about which said arm is swung up and down in a vertical plane.

19. In a sewing machine as set forth in claim 18, a cover member carried by said frame having an elliptical channel on its inner face into which said finger extends and along which'said finger travels, and a plate spaced inwardly from said cover member, said finger being arranged to travel around the periphery of said plate.

20; In a sewing machine as set forth in claim 19, said plate having an elliptical contour conforming substantially with that of the path of said finger.

21. In a sewing machine as set forth in claim 19, a thread guiding pin extending inwardly from said cover into the path of a portion of the needle threadwithin said head of the frame, and a cutter blade secured to said head adjacent said thread guiding pin, said blade having a cutting edge facing away from said guiding pin and out of the path of normal movement of the needle thread.

22. In a sewing machine as set forth in claim 21', said cover member being pivoted for outward rocking movement away from said head, said outward movement of said cover member being adapted to draw any loops of thread which may'become wrapped about. said thread guiding pin and said blade across the cutting edge of said blade to sever said loops.

23. In a sewing machine as set forth in claim 22, said thread guiding pin being mounted on said cover member for adjustable positioning thereon and in relation to said blade.

24. In a sewing machine as set forth in claim 18, a plurality of thread guiding elements adjustably mounted on said head below the path of movement of said finger, one of said guiding elements being in the path of said thread in the advance of the thread toward said finger, and another of said guiding elements being in the path of said thread between said finger and the needle.

References Cited by the Examiner UNITED STATES PATENTS Smith 112248 Mayer 112248 Johnson 112248 Backlin 112248 Engel et al 112248 JORDAN FRANKLIN, Primary Examiner.

G. H. KRIZMANICH, Examiner.

Claims (1)

1. IN A SEWING MACHINE HAVING A FRAME WITH AN OVERHANGING ARM WITH A HEAD PORTION AT ITS OUTER END, A DRIVE SHAFT JOURNALLED IN SAID ARM, A RECIPROCATORY NEEDLE BAR MOUNTED IN THE HEAD PORTION OF SAID ARM, A NEEDLE CARRIED BY SAID BAR, COMPLEMENTARY MEANS COOPERATING WITH SAID NEEDLE FOR PRODUCING A MULTIPLE THREAD STITCH, CONNECTIONS FROM SAID SHAFT FOR RECIPROCATING SAID NEEDLE BAR AND OPERATING SAID COMPLEMENTARY MEANS TO FORM A LINE OF STITCHING, MEANS FOR DIRECTING THREAD TO SAID NEEDLE, THREAD TAKE-UP MEANS IN THE PATH OF SAID THREAD FOR IMPARTING A TAKE-UP ACTION THERETO, CONNECTIONS FROM SAID SHAFT FOR OPERATING SAID THREAD TAKE-UP MEANS, THE COMBINATION WHICH COMPRISES A ROTARY MEMBER IN AT LEAST ONE OF SAID CONNECTIONS FROM SAID DRIVE SHAFT TO SAID NEEDLE BAR, SAID COMPLEMENTARY MEANS AND SAID THREAD TAKE-UP MEANS, SAID ROTARY MEMBER BEING MOUNTED FOR ROTATION IN A DIRECTION OPPOSITE TO THAT OF SAID SHAFT ABOUT AN AXIS REMOVED FROM BUT PARALLEL WITH THE AXIS OF SAID SHAFT, MEANS CARRIED BY SAID DRIVE SHAFT PROVIDING A FIRST CENTER OF MASS ECCENTRIC TO THE AXIS THEREOF, AND MEANS

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