US3038426A - Sewing machine attachment - Google Patents

Description

Jun 12, 1962 w. F. RICHARDSON ETAL 3,033,426

SEWING MACHINE ATTACHMENT Filed Feb. 20, 1959 3 Sheets-Sheet 1 IN V EN TORJ Will/27m F." filkhirdi fi L Gene Jper/y Affarney.

June 12, 1 w. F. RICHARDSON ETAL 3,038,425

SEWING MACHINE ATTACHMENT Filed Feb. 20, 1959 3 Sheets-Sheet 2 Ag 4 W4. M

June 12, 1962 w. F. RICHARDSON ETAL. 3,038,425

SEWING MACHINE ATTACHMENT 3 Sheets-Sheet 5 Filed Feb. 20, 1959 United States Patent Ofihce 3,.fi38A2b Patented June 112, 1962 3,038,426 SEWING MACHINE ATTACHMENT William F. Richardson and Gene Sperry, Carthage, Mo.,

assignors to Flex-O-Lators, Inc., Carthage, Mo., a corporation of Missouri Filed Feb. 20, 1959, Ser. No. 794,651 1 Claim. (Cl. 1122) This invention relates to new and useful improvements in sewing machines, and has particular reference to sewform a decorative pattern of stitching, over substantially the entire area of a mattress cover panel, prior to the application of the cover to the spring assembly of the mattress. Said cover panel may comprise an outer layer 'of fabric, an intermediate layer of paddling material, and

an inner layer constituting a Wire or wire-reinforced fabric. The purpose of the wire fabric is to support the padding material more uniformly and smoothly, and to prevent the padding material from working downwardly into or between the individual springs forming the spring assembly of the mattress. An extremely popular and widely used fabric of this nature constitutes spaced apart parallel wires extending in one direction, and spaced apart flexible cords extending transversely to the wires and being secured thereto at their points of intersection therewith.

*It will be apparent that with any conventional sewing machine, stitching through such a composite mattress cover will occasionally at least result in the fact that one or more of the wires of the reinforcing fabric will be struck squarely by the sewing machine needle, causing breakage of either the needle or the wire, or both. Breakage of the needle necessitates shutdown and repair of the machine, and breakage of the wire results in raw'and sharp Wire ends which will eventually work through the padding layers to the great discomfort of the eventual user of the mattress. The elimination of these difficulties is theprimary objective of this invention.

Generally, this object is accomplished by the provision of a special bobbin case for the sewing machine having the top thereof formed by the bed plate which supports the material being stitched, the wire fabric resting directly on the bed plate, and including mechanism for intermittently projecting a pair of fingers upwardly through said bed plate respectively at opposite sides of the needle and to move said fingers horizontally while extended, whereby to engage and move to one side any wire which may at that time be disposed directly beneath the needle, so

that the needle cannot strike it. Retraction of the fingers after each stroke of the needle permits the wires to move past the needle position, and the degree of deflection of the wire by the fingers is not suflicient to cause appreciable deformation of the composite material being stitched. The finger mechanism in no way hinders or affects the standard operation or synchronization of the bobbin and needle, but the bobbin drive may be utilized to drive the finger mechanism, so that the finger movement may be synchronized properly with the needle movement.

With these objects in view, as well as other objects which will appear in the course of the specification, reference will be had to the drawing, wherein:

FIG. 1 is a vertical sectional view of the bobbin case and related parts of a sewing machine, showing our invention, taken on a slightly irregular plane parallel to the bobbin shaft,

FIG. 2 is a top plan view, the bed plate shown in FIG. 1,

FIG. 3 is a top plan view of the device as shown in FIG. 1, with the bed plate removed and with portions broken away,

FIGS. 4 and 5 are sectional views taken respectively on lines IVIV and VV of FIG. 1, and

FIG. 6 is a fragmentary sectional view taken on line VI-VI of FIG. .1, showing various positions of the Wire sweeping fingers in dotted lines.

Like reference numerals apply to similar parts throughout the several views, and the numeral 2 applies to the lower arm portion of a sewing machine frame, shown fragmentarily, to the end of which is mounted the bobbin case indicated generally by the numeral 4. Said bobbin case has the form of a generally rectilinear box having a front wall 6, back wall 8, bottom wall It a right end wall 12 which is secured to frame 2 by a pair of screws 14, and a left end wall 16 which is hinged at its lower edge, as at 18, to bottom wall it). End wall 16 constitutes a door providing access to the case, said door opening outwardly. A cam 26 carried by said door is engaged by a leaf spring 22 affixed to bottom wall it? to urge said partially broken away, of

door yieldably toward its closed position. A bobbin shaft 24 extends horizontally from frame 2 into the bobbin case, being supported by a ball bearing 26 mounted in end wall 1 2 of said case. Mounted coaxially at the end of said shaft, within said bobbin case, is a fiat, cylindrical bobbin holder 28. A thread guide constituting a bar 3t} extends from front to rear across the bobbin case in closely spaced relation from the outer face of holder 23, and is secured at its ends in notches formed in the upper edges of front and back walls 6 and 8, as by screws 32. Said bar has a notch 34 formed in the edge thereof adjacent bobbin holder 28, directly above the geometrical center of said holder.

The top of bobbin case is formed by an upwardly convex bed plate as secured to end wall 12 of the case by screws 33, and over which the material 40' to be stitched is passed. Usually the material is mounted in a frame which is cam driven in a horizontal plane from a suitable template, whereby to produce the beautiful and intricate quilting patterns desired. This mechanism is not pertinent in itself to the present invention, and not shown. The bed plate is provided with a needle hole 42 through .which the sewing machine needle 44 reciprocates vertically, said needle passing downwardly through material 49, hole 42, notch 34 of the thread guard, and adjacent the face of bobbin holder 28. Although the actual sewing operation is not in itself a part of the present invention, it will be understood that as needle 44 reciprocates and bobbin holder 28 is rotated by shaft 24, a thread carried by needle 44- is passed by said needle through material 40 and caused to cooperate with a thread carried on a bob- 'bin in holder 28 to form stitches in material 40, in a standard sewing machine operation. Also, for reasons inherent in this operation, it will be understood that shaft 24 and bobbin holder 23 make two full revolutions for each full cycle of needle 44.

The material 463 to be stitched, as shown, constitutes an upper cover sheet 46 of fabric, an intermediate layer 48 of cotton batting or other padding material, and a lower reinforcing layer including a series of spaced apart, parallel wires 50, as best shown in FIGS. 1 and 4, the wire layer moving in contact with bed plate 36. Ln the standard sewing machine operation thus far described, it will be apparent that at least occasionally, the needle will strike one of wires 59 squarely, causing breakage of either the needle or the wire, either occurrence being highly objectional for the reasons discussed. The mechanism for preventing the needle from striking the wires forms the central subject matter of this invention, and will now be described.

A spur gear 52 is rigidly mounted by means of set screw 54 on bobbin shaft 24, said gear being disposed in a recess 56 formed in the outer face of end wall 12 of the bobbin case. Said gear meshes with a second gear 58 which is keyed rigidly to a cam shaft 60. Said cam shaft is disposed beneath and parallel to bobbin shaft 24, and is supported rotatably by a ball bearing 62 mounted in end wall 12, and a ball bearing 64 mounted in a bearing plate 66 alfixed to bottom wall of the case. intermediate said bearings, shaft 60 carries a circular cam 68 the axis of which is parallel to but eccentrically offset from the shaft axis. Said cam works in a cylindrical hole 70 formed in the lower section of a vertically disposed rocker plate 72, said rocker plate, as shown in FIG. 5, comprising a lower section 74- and an upper section 76 secured rigidly together by screws 78. A vertically elongated slot 86 is formed in the upper section 76, and bobbin shaft 24 extends through said slot. Mounted for free rotation on shaft 24 is a sleeve 82, and mounted rotatably on said sleeve is a rectilinear block 84, said block being provided with .a cylindrical bore 86 for receiving said sleeve, and being provided along each of its opposite vertical edges with a groove 88 which engages rocker plate section 76 slidably at the sides of slot 8i), whereby the rocker plate is supported for vertical sliding movement and angular tilting movement about shaft 24 as an axis, this vertical and tilting movement being imparted thereto by cam 68.

An A-shaped finger-supporting plate 90 is affixed to the upper end of rocker plate 72, and is disposed in a generally horizontal plane. It comprises a pair of side bars 92, as best shown in FIG. 3, each attached to the rocker plate by screws 78 and extending parallel to the bobbin shaft, and a pair of cross bars 94 and 96 extending transversely to and formed integrally with side bars @2, said cross bars being disposed respectively at opposite sides of the axis of needle 44. Alfixed to each of said cross bars by screws 98 is a foot plate 106, and extendtion will be imparted to plate 9% and fingers 102, and that as a result the upper ends of said fingers will follow a generally circular path in a vertical plane, as indicated by the dot-ted line positions of the fingers shown in FIG. 6. As indicated, during the upper portion of their circular travel, said fingers project above the upper surface of bed plate 56, and also move horizontally to traverse a vertical plane containing the sewing machine needle 44. Hence, if at the time of this movement a wire 50 of the material being stitched should be disposed directly in this vertical plane, so as to be disposed directly beneath the needle, it will be engaged and moved to one side by the fingers, in order that the needle on its next downward stroke will not strike said wire but will pass to one side of it. The very slight deflection of the wire thereby affected is in no way detrimental to the mattress cover being stitched. It will be apparent also that the fingers 182 will or may engage the padding layer 48, and that they also are moving horizontally relative to the padding. Thus the fingers may tend to displace some of the padding fibers, but the effect is so slight and so localized as to have no appreciable effect on the finished product. During the lower portion of the orbital movement of fingers 102, they are retracted below the surface of the bed plate, so that the wires 59 may pass freely thereover.

It is of course obvious that for maximum efiiciency, fingers 102 should sweep across the vertical plane of the wire in the instant during the downward stroke of the needle just preceding the arrival of the needle point at the elevation of the layer of wires 50 in the material 40 being stitched. in this connection, it may be noted that in this type of machine, the movement of material 40 is continuous and of uniform speed, but that the action of the needle is so rapid that the material movement does not cause breakage of the needle. Basically, the synchronization necessary to provide proper operation of the fingers relative to the needle results from the fact that the fingers are driven from bobbin shaft 24. The bobbin shaft is of course synchronized with the needle by standard parts of the machine, not shown, in order to provide proper coordination between the needle and bobbin threads. As previously described, the bobbin shaft turns two full revolutions for each full cycle of needle movement. For this reason, gears 52 and 58 are proportioned to turn cam shaft 60 through one revolution for each two revolutions of the bobbin shaft, so that fingers 102 bobbin shaft. It will be seen that by loosening set screw 54 securing said gear to the shaft, said gear may be turned independently of the shaft until the fingers are in exactly the desired relationship to the needle, and the set screw again tightened. An opening 106 is formed in end wall 12 to provide access to said set screw.

While we have shown and described a specific embodiment of an invention, it will be readily apparent that numerous minor changes of structure and operation could be made without departing from the spirit of the invention as defined by the scope of the appended claim.

What we claim as new and desire to protect by Letters Patent is:

An attachment for use in connection with a sewing machine having a bed plate and in which the material to be stitched is adapted to be moved continuously over said bed plate; and stitching means including a vertical needle reciprocably movable into and out of a hole formed therefor in said bed plate and operable to form stitches in said material, and a rotatably driven bobbin shaft extending beneath said bed plate and having a positive synchronous relationship to the movement of said needle; said attachment comprising a finger carried movably beneath said bed plate adjacent the axis of said needle and adapted to extend upwardly through a hole formed therefor in said bed plate; and means whereby said finger is driven to be alternately retracted beneath and extended above said bed plate, and when so extended to be moved horizontally to traverse a vertical plane including said needle, said finger driving means being interconnected with and driven by said bobbin shaft whereby said finger is synchronized with said needle to transverse the vertical plane of said needle just prior to the downward arrival of said needle at said bed plate, and consisting of a cam shaft carried rotatably beneath said bobbin shaft, means interconnecting said cam shaft with said bobbin shaft whereby the former is driven by the latter, a circular cam carried eccentrically by said cam shaft, a rocker plate disposed generally at right aoaaaae 6 angles to said bobbin shaft and said cam shaft and having above and below the material supporting surface of said a circular opening in the lower portion thereof in which bed plate. said cam is engaged, the upper portion of said rocker r 1 plate being mounted on said bobbin shaft for vertical References Cited In the file of this intent sliding movement and oscillatable pivotal movement rela- 5 UNITED STATES PATENTS tive thereto, said finger being carried by said rocker plate, 1,732,394 Bebel Oct. 22, 1929 whereby movement of said rocker plate by said cam will 1,924,737 Ferrara Aug. 29, 1933 impart to the upper end of said finger movement in a 1,942,903 Roseman Jan. 9, 1934 generally circular path in a vertical plane, the upper and 2,700,351 Schaad I an. 25, 1955 lower portions of said path being disposed respectively 10 2,771,848 Knaus et al Nov. 27, 1956

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