US2438636A - Sewing machine - Google Patents

Description

March 30, 1948. M. G. IVANDICK SEWING MACHINE Filed Jan. 1, 1945 2 Sheets-Sheet 1 mawe ZiF A;

March 30, 1948. M. G. lVANDlCK SEWING MACHINE Filed Jan. 1, 1945 Sheets-Sheet 2 Patented Mar. 30, 1948 SEWING MACHINE Matthew G. Ivandick, Rockford, 111., assignor to Free Sewing Machine 00., Rockford, 11]., a corporation of Illinois Application January 1, 1945, Serial No. 570,869

4 Claims. (01. 112-241) This invention relates to sewing machines, and is more particularly concerned with a one-to-one constant speed drive, as distinguished from the conventional two-to-one constant speed drives and the one-to-one variable speed drives.

In the old machines having one-to-one variable speed drives and two-to-one constant speed drives, it has been necessary to connect the cloth feed control with the upper shaft, and that necessarily complicates the construction considerably, making these machines far more expensive to manufacture, much heavier, and more apt to get out of order and require expensive repairing periodically. These considerations alone, it would appear, should have dictated the invention and production long ago of a commercially acceptable one-to-one constant speed drive machine, but they are by no means the only considerations; there are the following:

(1) A constant speed one-to-one drive reduces vibration, thereby producing a smoother runnin machine;

(2) A constant speed one-to-one drive means more power on the lower shaft turning the hook;

(3) Constant speed one-to-one drive means a reduction in the speed of the lower shaft, thus prolonging the life of the machine;

(4) Constant speed one-to-one drive insures better upper thread control, as compared with a variable speed one-to-one drive wherein the bobbin case slows down and speeds up in each rotation, causing jerky and uneven shedding action, and

(5) Constant speed one-to-one drive permits more accurate timing between the hook and take-up.

One-to-one ratio drives havebeen disclosed in patents, but, so far as I am aware, there has been no commercially successful sewing machine embodying such a drive, and in view of the numerous advantages just mentioned, the conclusion is inescapable that the one-to-one ratio drives disclosed in the patents were not practical for certain reasons. It is, therefore, the principal object of my invention to provide a practical form of one-to-one constant speed drive for sewing machines.

The salient feature of my invention is the provision of a novel cam means for actuating the take-up arm in the correct timed relationship to the operation of the needle bar and rotary hook, the take-up arm being preferably springpressed to move upwardly and having a roller mounted thereon and operating as a follower in the cam track in the face of a rotary cam turning with the needle bar operating shaft. The crank pin cooperating with the pitman rod for reciprocating the needle bar in timed relation to the turning of the upper shaft is, in accordance with my invention, utilized also to turn the cam and support it in the proper plane for operation of the take-up arm.

The invention is illustrated in the accompanying drawings, in which Fig. 1 is a view of a sewing machine partly in front elevation and partly in vertical section, embodying the one-to-one constant speed drive in accordance with my invention;

Figs. 2, 3 and 4 are end views of the machine. showing the parts in different relationships throughout a single revolution of the upper and lower shafts, and

Fig. 5 is a horizontal section on the line 5--5 of Fig. 2.

The same reference numerals are applied to corresponding parts throughout the views.

In the drawings, the reference numeral 8 designates the cloth plate, 9 the column projecting upwardly therefrom, and I0 the arm from which the needle bar ll carrying the needle l2 extends for operation. The presser bar l3, shown in Figs. 2, 3 and 4 behind the needle bar H, carries the usual pressure foot l4 that is held down in contact with the cloth plate under spring pressure in the usual way, but may be raised to an out-ofthe-way position by operation of the lift lever I5 in the well-known manner to permit entry or removal of work. Indicated at IS in Fig. 1 are the usual cloth feed dogs operable through slots I! in the cloth plate under the presser foot, and I8 is the rotary hook comprising a thread loop carrier supporting for relative rotational movement a bobbin case base [9 which in turn rotatably supports a bobbin retained in the base by a case in the well-known manner as illustrated, for example, in the Southam et a1. Patent 2,065,349. The rotary hook I8 is turned by means of a lower shaft 20 supported in bearings under the cloth plate and connected by gears 2| with a vertical shaft 22 in the column 9 to operate in the desired one-to-one relation with the upper shaft 23, with which the shaft 22 is connected by gears 24. A handwheel 25 is operatively connected with a gear 26 meshing with one of the gears 2| to permit manual operation of the machine. Suitable drive means is provided for power operation of the machine, a pulley 25a being indicated in frictional contact with the handwheel 25, the shaft 25b being driven by an electric motor (not shown).

This pulley may be disengaged from the handwheel 25 and engaged with a bobbin winder (not shown) in the manner disclosed in my co-pending application, Serial No. 529,131, filed April 1, 1944, which resulted in my Patent No. 2,417,417, issued March 18, 1947. While the speed of the motor driving the pulley 25a may be varied by means of a rheostat in the conventional manner, it should be clear that for any given speed'setting of the rheostat the shafts 20 and 23 are driven in a one-to-one constant speed relationship.

The shaft 21 disposed in parallel relation to the lower shaft 20 under the cloth plate is provided for adjusting the stitch regulating and reversing cam or cross-head 28 that is disposeddir'ectly beneath and in close proximity to the rotary hook IS, in accordance with the disclosure inmy co-v pending application, Serial No. 545,778, filed July 20, 1944, which resulted in Patent No. 2,420,480, issued May 13, 1947. A pin 29 carried on the lower end of an arm 36 is slidable in a diametri cally extending slot 3| provided in the cam 28.

The upper end of the arm 30 has a circular hole 32 therein rota'tably receiving an eccentric 33 that is keyed, as indicated at 34, on the end portion of the shaft 29. Another eccentric 35 is also keyed on the shaft 29 with the same key, and-is slidable and rotatable in an elongated opening 36 provided in a carrier plate 31 on which the cloth feed dogs are mounted, as indicated at 38. The plate'31, as fully disclosed in the co Pending ap plication, is given the same vertical reciprocation at all times due to the fact that the eccentric 35 has a fixed throw, but the reciprocatory movement of. the plate 31 and the cloth feed dogs 16 in a horizontal direction, fore and aft relative'to the cloth plate 3, depends upon the angular adjustment of the cam 28, and the feed is in a forward direction or reverse direction, depending upon the direction of inclination of the slot 3|. A manually adjustable bell crank lever 39', pivoted as at 40 on the lower end of the column 9, has an arm inside the column connected by means of a link 4| to an arm 42 provided on the inner end of the shaft 21. The lever 39', as dis closed in the co-pending application, is set relative to a scale 43 that is graduated-in terms" of the number of stitches per inch which the machine is adapted to sew when the lever 39 is set with its pointer indicating a specified number of stitches per inch on the scale, forward and reverse sewing being indicated on the scale-and the scale reading right and left from a zero point at the middle of the scale, which is the neutral point corresponding to vertical disposition of the slot'3 I.

The upper shaft 23, which has already been described as driven in a one-to-one ratio relationship with the lower shaft 29, has a counterweighted crank 44 on the outer end thereof that is connected by means of a crank pin 45 and-pitman rod 46 with the upper end of the needle bar H. V The crank pin 45, in accordance with my invention, serves as the support for a cam di'sc 41 in concentric spaced parallel relationship to the crank 44and immediately behind a cross-bar 48, as best appears in Figs. 1 and 5. The crossbar 48 has the needle thread take-up arm 49 pivoted thereon, as indicated at 59, and the pin forming the pivot 59 serves as a support for'the coiled portion 51 of a grasshopper spring, one arm 52 of which is anchored at its outer cndto the face plate 53, and the other arm 54 of which has its outer end anchored to the arm 49, whereby normally to tend toturn the armin a clockwise direction relative to the-piv'ot-pin 59. The takeup arm has the long end thereof extending through a slot in the face plate 53 for connection with the needle thread in the usual manner, and the short end of said arm carries a pin 55 which extends through an arcuate slot 56 in the crossbar 48 and has a roller 51 thereon working in the cam groove 58 provided in the outer face of the cam disc 41. The groove 58, as clearly appears in Figs. 2,3and 4, is of a form concentric with the disc 41 and shaft 23 throughout approximately 180 so that the take-uparm 49 remains in the lower position throughout approximately 180 turning of the shafts 20 and 23 while the follower roller 51 is operating idly in this dwell, as appears i'n'Figs. 2 and 3, which show the disc 41 in two positions about 180 apart. The high point 59 of the cam groove is approximately at the middle of the other 180 portion of said groove, and the take-up arm 49 will accordingly be given its full rise in about 90 turning of the disc 41, as illustrated in Figs. 3 and 4, which show the disc in two positions approximately 90-apart. The re turn movement of the take-up'arn 49 likewise occurs in approximately 90 turning of the disc 41. Therotary hook l8, when the parts are in the position shown in Fig. 2, is taking hold of the loopof thread in theneedle l2 to commence the forming of a stitch, and when the parts are in the position shown in Fig. 3 thehook I8 is about to shed the loop. It is between this position of the hook l8 shown in Fig. 3, and the position approximately 90 advanced shown in Fig. 4, that the take-up arm 49 should be operated to complete the stitch, leaving the hook 18 of course free to take" hold of the next loop when the hook arrives again at the position shown in Fig. 2. The take up arm 49 is returned in this interval, allowing the needle l2 to go down on the starting of a new stitch. With myimproved construction, the take-up arm 49 is opera-ted 'smoothlyandpositively with close accuracy as to timing with relation to the operation of the hook so that/there is no danger of the needlethread breaking and the stitches are neat and uniform. In passing, it-will,

of course, be understood that the thread going from the usualspool in or on the'arm l0 isfiex; tended through a suitable tension device 60 and check spring 64, andis extended from the check spring through theeye 62 in the end of thetakeup arm, andfrom there down through the eye of the needle- 12 in the usual way.

In conclusion, I wish topoint out that the cam disc 41 may if desired [be made having onlythe projectingmarginal cam track portion 53 providing acam profile similar to that in the outer portion of the groove 58 and having a high point at the same angularity as the high point 59 in the groove 58, the spring '51 cooperating with the take-up arm to keep-the roller 51 in close contact with said profiled cam track portion at all times. The operation with such a construction is'substan'tially the same as withthe other construction, Y

but itis believed it would be moreeconomical to manufacture. on the other hand, the cam disc 41- may be left as shown with 'a two-walled cam 1 In a sewing ma hine having a reciprocating needle'and a loop-taker cooperating therewith to produce lock-stitches, the combination of interconnected upper and lower shafts and drivin means therefor to turn the shafts at a substan tially constant speed and one-to-one ratio, the lower shaft having driving connections with the loop-taker, a crank on the upper shaft carrying a crank pin, a pitman rod pivoted thereon and a needle bar carrying the aforesaid needle operatively connected with said pitman rod, a needle thread take-up arm pivotally mounted to oscillate in a plane parallel to the plane of rotation of the crank, and a cam disk carried on the crank pin and in coaxial relation to and turning with the upper shaft and having a cam track thereon extending annularly relative to the axis of the upper shaft throughout 360 and cooperating with follower means carried directly on the take-up arm to operate the latter in its thread take-up movements in a predetermined timed relationship to the operation of the needle and loop-taker.

2. In a sewing machine, the combination with an upper shaft, drive means therefor, a crank on said shaft, and a needle bar arranged to be reciprocated in the rotation of said crank in a predetermined angular timed relationship, said crank having a crank pin thereon pivotally connected to a pitman rod which in turn is pivotally con nected to the needle bar, of a circular cam disc disposed in concentric spaced parallel relation to said crank and connected thereto by said crank pin in such spaced relation, said disc having a cam track groove provided therein, a follower operable in said groove, a needle thread take-up element mounted for oscillatory movement in a plane parallel to said cam disc and carrying said follower directly thereon, and spring means tending normally to move the take-up element in one direction, whereby the follower on the take-up element is maintained in close contact with one side of the groove in the cam disc for closer timing in the oscillation of said take-up element.

3. In a sewing machine, the combination with an upper shaft, drive means therefor, a crank on said shaft, and a needle bar arranged to be reciprocated in the rotation of said crank in a predetermined angular timed relationship, said crank having a crank pin thereon pivotally connected to a pitman rod which in turn is pivotally connected to the needle bar, of a circular cam disc disposed in concentric speed parallel relation to said crank and connected thereto by said crank pin in such spaced relationship, said disc having a cam track provided thereon, a follower engaging said track, a needle thread take-up element pivoted intermediate its ends for oscillatory movement in a plane parallel to said cam disc and carrying said follower thereon on one end, and spring means tending normally to swing the takeup element in one direction to maintain the follower in close contact with the cam track.

4. In a sewing machine having a reciprocating needle and a loop-taker cooperating therewith to produce lock-stitches, the combination of interconnected upper and lower shafts and driving means therefor to turn the shafts at a substantially constant speed and one-to-one ratio, the lower shaft having driving connections with the loop-taker, a crank on the upper shaft carrying a crank pin, a pitman rod pivoted thereon and a needle bar carrying the aforesaid needle operatively connected with said pitman rod, a needle thread take-up arm pivotally mounted to oscillate in a plane parallel to the plane of rotation of the crank, a cam disk carried on the crank pin and in coaxial relation to and turning with the upper shaft and having a cam track thereon extending annularly relative to the axis of the upper shaft throughout 360 and cooperating with follower means carried directly on the take-up arm to operate the latter in its thread take-up movements in a predetermined timed relationship to the operation of the needle and loop-taker, and spring means tending normally to swing the takeup arm in one direction to maintain the follower means in close contact with the cam track.

MATTHEW G. IVANDICK.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 389,788 Bolton Sept. 18, 1888 977,630 Hohmann Dec. 6, 1910 1,081,841 Von Korytynski Dec. 16, 1913 FOREIGN PATENTS Number Country Date 164,400 Great Britain June 16, 1921 437,645 France Apr.-25, 1912

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