US3001490A - Buttonhole attachment for sewing machines - Google Patents

Description

p 1961- G. M. BRAUER 3,001,490

BUTTONHOLE ATTACHMENT FOR SEWING MACHINES Filed Nov. 3, 1958 "Jilllliii 3,001,490 BUTT ONHOLE ATTACHMENT FOR SEWING MACHINES Gerhard Brauer, M. Gladbach, Germany, assignor to Fremaco International, Inc, Chicago, 11]., a corporation of Illinois Filed Nov. 3, 1958, Ser. No. 771,613 Claims. (Cl. 112-77) This invention relates, as indicated, to buttonhole attachments for sewing machines. More particularly, this invention relates to a buttonholer which avoids replaceable templates, and is adjustable for different sizes of buttonholes.

Buttonhole attachments for automatically making, or sewing, buttonholes with conventional sewing machines are known. Such attachments have a series of adjustments, or settings, which must be made before sewing, for instance, setting of the buttonhole length, stitch width, number of stitches, tightness of stitches and also often width of the slitting space, by loosening, or tightening of nuts, or screws, or by shifting of levers. Through such actions disturbances may be caused which are not likely to be eliminated by operators who are not sufficiently trained. The fewer adjustments, or settings, there are to be made, the easier, and safer, it is to operate a buttonholer. The present invention meets this desirable simpliiication, since only one operation is necessary for setting the selected buttonhole length.

Another advantage of the buttonholer of the invention is that it is confined to the same stitch width and number of stitches for all sizes of buttonholes which, however, are balanced so as to give the most commonly used buttonhole, middle size, a proportionally suited denseness of the row. The denseness of the row, which, due to the constant number of stitches, is less with large buttonholes and more with small buttonholes, has the further advantage that, in accordance with the usual practice, the large buttonholes may be made with strong thread, and small buttonholes with line thread, by which also such variable buttonholes obtain a row denseness suitable to their size. An advantage related to the foregoing is that the single setting, or adjustment, i.e., the setting of the buttonhole length, may be accomplished without loosening, or tightening of nuts, or screws, and without changing templates.

Further objects and advantages of this invention will become evident as the description proceeds and from an examination of the accompanying drawing which illustrates one embodiment of the invention, and in which similar numerals refer to similar parts throughout the several views.

In the drawing:

FIGURE 1 is a side view of a device embodying the invention, shown partly in section;

FIGURE 2 is a top plan view of the device shown in FIGURE 1;

FIGURE 3 is a bottom view of the device shown in FIGURE 1;

FIGURE 4 is a sectional view taken substantially along lines 44 of FIGURE 2;

FIGURE 5 is a sectional view taken substantially along lines 5-5 of FIGURE 2;

FIGURE 6 is a sectional view taken substantially along lines 6*6 of FIGURE 1;

FIGURE 7 is a sectional view taken substantially. along lines 77 of FIGURE 1; and

FIGURE 8 is a perspective view of the lower end of the vertical hollow shaft showing the cam used for shifting the feed plate.

The buttonholer of the invention has a housing 10 with an adapter 11 by which the device may be secured rates atent ice to the presser bar of a sewing machine. Attached to the housing 10 is a conventional ratchet and pawl mechanism 12, 13 for rotating shaft 14. The ratchet 12 is affixed to shaft 14. The pawl is pivoted at 15 on forkarm 16, the latter of which is loosely mounted on shaft 14. The pawl is urged into engagement with ratchet wheel 12 by a spring 17. The fork-arm 16 has a bifurcated end designed to be engaged with the needle bar of a sewing machine, so as to be oscillated upon reciprocation of the needle bar. This will effect step-by-step rotation of the ratchet wheel by action of the pawl, and, therefore, the shaft 14.

Secured to the shaft 14 is a sinusoidal cam 18. A cam follower 19 projects into engagement with the sinusoidal cam 18 and is mounted on a plate 20. Plate 20 is pivoted at its rearward portion about a vertical. hollow shaft 21. Depending from the plate 20 is a tongue 23 that fits into a groove or slot 24 of a cloth holding lever in the form of feed plate 25. Thus, as the cam follower 19 is moved from side to side by the sinusoidal cam 18, this movement is transmitted to the feed plate 25 by the tongue and groove connection between the plate 20 and feed plate 25. At the forward end of the feed plate is a feeding foot 26 provided with an opening for a needle and a roughened lower face to engage and move the cloth which is being sewed.

Slot 24 extends rearwardly of hollow shaft 21, so that the feed plate may be moved longitudinally relative to shaft 21.

Also, afiixed to the shaft 14 is a worm 30. Aflixed to the vertical hollow shaft 21, and engaging worm 30, is worm gear 32. Thus, the rotation of shaft 14 by the ratchet and pawl mechanism is imparted to the hollow shaft 21.

At the lower end of the hollow shaft 21 is secured an eccentric cam '33 of a configuration to fit within the slot 24, so that the feed plate 25 is pivotally and slidably mounted thereon. As the sinusoidal cam produces a zig zag movement of the feed plate through cam follower 19, plate 20, and tongue 23, engaging slot 24, the feed plate oscillates by a pivotal action about the eccentric cam 33. The eccentric cam 33 is also used to shift the feed plate laterally at the end of the longitudinal stroke, as the hollow shaft 21 is rotated.

A template 35 in the form of a shaped disc is employed to produce the longitudinal movements of the feed plate. The template is slidably mounted on the straight sided extremity 37 of hollow shaft 21. The template is rotated by shaft 21. A slot 36 in the template receives the straight sides 37 at the end of the hollow shaft 21, so that the template is turned by shaft 21, but may slide along slot 36 relative to shaft 21 when it is desired to vary the position of the template on shaft 21.

A shaft 40 is journaled in the bore 41 of hollow shaft 21 and extends upwardly therethrough. At the lower end of the shaft 40 is a shoulder 42 which may be in the form of a circular plate. Shoulder 42 extends along the lower face of template 35. The shoulder 42 is dimensioned larger than slot 24 in order to maintain the feed plate 25 on the eccentric cam 33 and hold the template 35 on the straight sided extremity of hollow shaft 21.

On the inner face of shoulder 42 is a crankshaft pin 43 which projects into an opening 44 of thetemplate 35, as best shown in FIGURES l, 3 and 4. At the upper end of the shaft 40 is a manual knob 45. The manual knob 45 may be threaded on the shaft 40, but is nonrotatably held, or secured, to the shaft by a key 46. The knob 45 is used to turn crank pin 43.

' The knob 45 is held with sutlicient friction against gear 32 so that the knob and gear, and thus shafts 40, 21 rotate as a unit when driven by worm 30. However, the shaft 40 may be turned by rotation of knob 45 to change the position of shaft 21 in template 35 along slot 2 36 by the action of crank pin 43.

An aperture 48 may be formed on the knob 45- in order to view indicia 49 marked on the upper surface of worm gear 32. The indicia on the Worm gear 32 indicates the length of the buttonhole for any particular setting of the template disc on shaft 21. As the knob 45 is rotated it turns the shaft 40 relative to-shaft 21 so as to vary the eccentricity of key 46 about which the template 35 pivots.

On the lower surface of the feed'plate 25 are mounted two transverse ledges forming shoulders 50, 51 for engaging the template 35. As the template 35 is rotated, the feed plate 25 is moved longitudinally by the action of the shoulders 50, 51 against the template 35.

At the end of the longitudinal stroke the feed plate is shifted by cam 33 bearing against the sides of slot 24. The template and cam 33 are, as illustrated, shaped to produce the desired movements of the feed plate.

From the foregoing, the operation of the buttonholer of the invention is believed to be apparent. The buttonholer is secured to the presser bar of a sewing machine by adapter 11. The fork-lever 16 is driven up and down by the needle bar to operate the ratchet and pawl mechanism in order to turn shaft 14. The sinusoidal cam 18 causes the feed plate 25 to oscillate in a zig zag pattern through cam follower 19, plate 20 and tongue 23, the latter of which fits in groove 24 of the feed plate. The feed plate transmits the Zig zag movement to the front end which moves the feed foot 26, and the cloth held by it, to and fro. The feed plate is guided, and pivoted, at its rearward end by eccentric cam 33.

The hollow shaft 21, which is turned by worm gear 32, rotates the eccentric cam 33 and the template 35. Since the template 35 is eccentrically mounted, the feed plate 25 is moved along a longitudinal line forwardly and rearwardly by action of the template against the shoulders 50, 51. In addition, the eccentric cam 33 shifts the feed plate 25 to a small distance from side to side at the ends of the longitudinal movement in such a manner that there are formed two parallel lines of zig zag stitches that are connected at both their ends by zig zag stitching.

Because an entirely circular shaping template 35 would slow down the movement of feed plate at both ends of the longitudinal stroke, which would prevent the zig zag stitches from being equally dense, the template is shaped, as illustrated in the drawing, in such a way that it speeds up its motion at both ends. The shape of the eccentric cam 33, as illustrated, and the template 35, is such that the eccentric cam 33 comes into effect to shift the feed plate at the two termination points of the longitudinal movement. The stroke of the template is varied by turning the shaft when manual knob is rotated. In this way, the template 35 is shifted by crankshaft pin 43 on the straight sides of sides 37 of shaft 21 in order to vary the eccentricity of the template. The length of the stroke of the template 35, thus changed can be precisely predetermined by the indicia appearing on the upper face of worm gear 32, as view through aperture 48 in knob 45.

In the drawing and specification there has been set forth a preferred embodiment of the invention, and although specific terms are employed, these are used in a generic and descriptive sense only, and not for purposes of limitation. Changes in form and the proportion of parts, as well as the substitution of equivalents are contemplated, as circumstances may suggest or render expedient, without departing from the spirit or scope of this invention as further defined in the following claims.

I claim:

1. In a sewing machine attachment, the combination comprising a frame, a first shaft rotatably mounted on said frame, means for rotating said first shaft, a cloth holding member pivoted intermediate its ends having a cloth engaging foot thereon, template means driving said first shaft operatively engaging and for reciprocating said cloth holding member longitudinally, said template means slidably connected to said first shaft at one end, a second shaft journalled in and for movements relative to said first shaft, manually operable means at the other end of said first shaft secured to said second shaft, and shifting means connected to said second shaft at said one end of said first shaft and engaging said template means for slidably shifting said template means relative to said first shaft to vary the position of the vertical axis about which said template means rotates so as to change the length of the longitudinal stroke of said cloth holding member.

2. In a sewing machine attachment, the combination comprising a frame, a first shaft rotatably mounted on said frame, means for rotating said first shaft, a cloth holding member pivoted intermediate its ends having a cloth engaging foot thereon, template means in the form of a shaped disc operatively engaging said cloth holding member, said template means slidably mounted on one end of said first shaft for rotating said template means about a vertical axis to reciprocate said cloth holding member longitudinally, a second shaft journalled in and for movements relative to said first shaft, a member connected between said second shaft and said template means for slidably shifting said template means relative to said first shaft to vary the position of the vertical axis about which said template means rotates, and manually operable means connected to said second shaft at the end of said first shaft opposite to said template means for changing the length of the longitudinal stroke of said cloth holding member.

3. A sewing machine attachment comprising, a frame, a first shaft rotatably mounted on said frame, means for rotating said first shaft, a pivotally mounted cloth holding member having a cloth engaging foot thereon, template means operatively engaging with said cloth holding member for reciprocation, said template means 7 slidably mounted on one end of and non-rotatable with respect 4. A sewing machine attachment comprising, a frame,

a first shaft rotatably mounted on said frame, means for rotating said first shaft, a pivotally mounted cloth holding member having a cloth engaging foot thereon, template means in the form of a shaped disc operatively associated with said cloth holding member, said template means slidably mounted on one end of and non-rotatable relative to said first shaft, a second shaft, lever means at said one end of said first shaft connected to said second shaft and to said template means for slidably shifting said template means relative to said first shaft to vary the position of'the vertical axis about which said template means rotates in order to change the length of the longitudinal stroke of said cloth holding member, and a knob member secured to said second shaft at the other end of said first shaft opposite to said template means for changing the length of the longitudinal stroke of said cloth holding member.

5. In a sewing machine attachment the combination comprising a frame, a cloth holding member having a cloth engaging foot for longitudinal reciprocating movements, means for producing longitudinal movements of said cloth holding member including a horizontal shaft journalled in said frame, a ratchet wheel mounted on said horizontal shaft, a fork arm pivoted on said frame with a pawl thereon to effect a step-bystep rotation of said horizontal shaft, a first vertical drive shaft, means connected to said horizontal shaft for rotating said first shaft, template means slidably mounted on and driven by said first shaftandrotated thereby, said template means, operatively engaging said cloth holding member for longitudinally reciprocating the latter, a second shaft journalled in and extending beyond the ends of said first shaft, shifting means connected to one end of said second shaft and to said template means for slidably shifting the latter relative to said first shaft, and manually operable means connected to the opposite end of said second shaft.

References Cited in the file of this patent UNITED STATES PATENTS 246,765 Harris Sept. 6, 1881 6 Gilbert Oct. 14, 1884 Pratt Dec. 15, 1885 Hargraves et a1. July 16, 1901 Leberecht June 21, 1921 Serafini Oct. 20, 1925 Lotts Mar. 10, 1936 Zonis Jan. 20, 1942 Russell Aug. 18, 1953 Russell Nov. 24, 1953 FOREIGN PATENTS France Feb. 27, 1952

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