US2669206A - Needle stabilizer for sewing machines - Google Patents

Description

Feb- 16 1954 B. P. PINKvoss ET AL 2,669,206

ATTRNE Y Feb 16 1954 B. P. PlNKvoss E-r AL l 2,669,206

' NEEDLE STABILIZER FOR SEWING MACHINES Filed D90. 15,-1951 2 Sheets-Sheet 2 A'ITRNEY Patented Feb. 16, I1954 NEEDLE STABILIZER FOR SEWING MACHINES Berthold P. Pinkvoss, Stratford, and Stanley J. Ketterer, Bridgeport, Conn., assignors to The Singer Manufacturing Company,

Elizabeth,

N. J., a corporation of New Jersey Application December 15, 1951, Serial No. 261,778

Claims.

This invention relates to needle stabilizing devices for a sewing machine and particularly to a needle stabilizing arrangement adapted for use with a sewing machine having either a freely rotatable presser-wheel or a driven work-feeding presser-wheel. It is an object of this invention to provide a needle stabilizer which is effective accurately to -guide the point of a slender needle to the desired stitch line with a minimum of frictional drag or lbending of the needle, thereby prolonging the useful life of the needle.

. When stitching a, straight seam in a material such as leather, it is frequently desirable to guide ithe needle point to the work, thereby overcoming the effect, for instance, of needle vibration due to the use of a relatively slender needle. One highly efficient type of needle stabilizer construction involves the use of an Lunyielding needle guiding surface arranged at a sharp angle with the needle bar and against which the needle point glances so as to be cammed into proper work penetration position. As an example, the patent to Knox, No. 1,864,136, June 2l, 1932, discloses this type` of needle stabilizer in which the needle guiding surface is formed asv an integral part of rthe roller presser.

In the various embodiments of that described type of needle stabilizer construction,` the needle -guiding surfaces are firmly supported tol prevent .movement thereof laterally of the line of stitch formation. Apparently it was felt that the needle point must be cammed into proper position in the most positive manner. As a result, considerable friction is developed between the needle blade and the guiding surface, which friction has a detrimental effect on the needle. In the Knox construction, an attempt was made to alleviate this objectionable excessive friction by inclinf ing the needle from the vertical so that, in theory,

only the needle point would touch the guiding surface formed on the presser roller. In practice, however, it has been observed that with certain types of materials the needle, after penetration of the work,is drawn laterally in the direction of the presser roller thus causing increased friction therebetween. The consequent effect of such excessive friction is detrimental to the life of the needle and in certain instances vvresults in an objectionable permanent bend in the needle blade.

l We have found that absolute rigidity of the needle stabilizer against movement laterally of #the line of Vstitch formation is not essential to satisfactory needle positioning but, on the contrary, a considerable amount of flexibility is permissable. With a. somewhat flexible needle stabilizer, it becomes apparent that the action of the stabilizer upon the slender needle point is more in the nature of a parrying than a camming action. Accordingly, we provide in the present invention, a needle stabilizer which is yieldable laterally of the line of stitch formation. In normal unflexed position, the stabilizer extends across the axis of the needle bar and it is spaced suiciently from the surrounding objects so that movement is permissable to compensate for the above described lateral drawing effect. With this fiexible stabilizer, the frictional `drag between the needle blade and the stabilizer is substantially constant depending in amount primarily upon the flexibility of the stabilizer.

Other objects and advantages will appear from the following specification and the accompanying drawings which illustrate the preferred embodiment of our invention and in which:

Fig. 1 represents a longitudinal sectional View of a. portion of a sewing machine to which the invention is applied and taken in a vertical plane passing substantially through the needle.

Fig. 2 is an end elevational View, partly in section, of the portion of the sewing machine illustrated in Fig. 1 with the end cover plates removed.

Fig. 3 is an enlarged front elevation View, partly in cross section, of the rearward presser and needle stabilizer o-f Figs. l and 2, with the ad- .jacent parts illustrated fragmentarily.

Fig. 4 is an enlarged fragmentary view of that portion of the roller presser and needle stabilizer of Fig. 3 adjacent the work, and in which the needle and the stabilizer are illustrated in three different positions during a typical cycle of stitch formation.

Fig. 5 is a front elevational view partly in cross section and similar to Fig. 3, but showing a modied form of roller presser and needle stabilizer.

The selected embodiment the invention is i1- lustrated as applied to a lock stitch post machine which comprises a frame of which a vertically arranged work supporting post Il and an over# hanging bracket-arm I2 are illustrated. Rotatlably journaled in the post Il, is a hook shaft I4 to which a rotary hook l5 is secured, and a feed driving shaft I6 which is connected by bevel gears I'I-II to a lower feed wheel I8. The hook shaft I4 is driven in the usual continuous fashmittently in one direction by a suitable driving arm I2 and is operatively connected for endwise` reciprocatory movement by means of a driving link 26 and a crank 21 fast on a rotary shaft 28 arranged Within the bracket-arm. Also endwise slidably journaled in a bracket-arm l2 is a presser-bar 30 to the lower extremity ofwhich'is i secured a supporting arm 3l-for. an inclined studi shaft I32. A portion of the stud-shaft is threaded. as at 33, and is formed on the unthreaded extremity with a conical ball bearing race 34:l Engaging the stud shaft threads 33 is a bearing conning member 35 having a second conical ball bearing race 36 formed thereon. The stud shaft 32 is rigidly secured to the arm 3| by a clamp .arrangement between the bearing coni-lning member 35 and a fastening nut 3T.. A driven presser wheel 38 which Lis rotatably journaled on the stud shaft 32 by means of bearing balls 39--39\, is provided with a knurled peripheral portion 4i! which is arranged above the lower `feed wheel I8. The slight inclination of the stud shaft 32 and consequently of the presser-wheel -38 provides clearance forthe needle bar and permits the presser wheel to be disposed nearer to the needle path. Integral with the presser wheel 38 is a pulley 4| which is engaged by an endless belt 42 connecting the presser wheel with the feed wheel drive shaft IB throughsuitable connectons (not shown) .in'the machine frame.

Referring to Figs. 3 and 5, the needle stabilizer, indicated generally as 50, is carried by the presser device. The stabilizer isV preferably fabricated of sheet metal in the form of a dish-shaped circular disk. More particularly, the stabilizer is formed with a hat central portion i which denes a single plane. 'The flat centraly portion merges into a generally irusto-conical marginal portion 52 and of which an outer peripheral rim 53 is bent into a plane vsubstantially parallel to l'the plane of the flat central portion 5l.

k'ner in which the stabilizer is secured tothe presser device. In eachconstruction, however, the stabilizer is inclined vfrom the vertical because of the inclination of the stud shaft '32 and vpresser wheel 38.Y In Fig. 3, the stabilizer is fastened at its' lcenter to the freel end of the stud 'shaft 32 by means of a single fastening kscrew 60 which is threaded into a hole formed centrally of the stud shaft.` lThe shape of the marginal portion 52 and Vtherinr 53 ofthe stabilizer is generally similar to that yof theadjacent` face 44 of "the presser wheel, and consequently the space between the stabilizer and the face'44 is available f to .permitmaximum freedom of nexiblity of the 4 rim 53 without contact between the stabilizing disk and the face 44. The presser wheel 38 of Fig. 3 is preferably provided with a shallow angular recess 43 in order to provide additional clearance for flexing of the stabilizer. The stabilizer of Fig. 3 therefore, remains locked against turning as does the stud shaft 33. By means of the fastening screw G0, however, the stabilizer may be readily loosened and turned to a new angular position to present a fresh face to the needle in case of wear.

In Fig. 5 a construction is illustrated in which the stabilizer is secured to a portion of the adjacent face 44 of the presser wheel and therefore, rotates with the presser wheel so that the rim portion ofthe stabilizer which is presented to the needle is constantly varied. Preferably a plurality of fastening screws -65 are utilized for this purpose, each being threaded into the presser-Wheel 33. With this construction, an aperture 54 is provided in the center of the stabilizing disk to provide access to the 'stud-shaft 32 so that the presser device may be disassembled without removing the stabilizing disk.

Figs. 3 and e each illustrate the needle 23 in three positions during a typical cycle of needle reciprocation. In each iigure, the uppermost position illustrates the needle kduring that portion of the cycle in which it is raised free of the Work 4and the stabilizer; the intermediate or central position illustrates the :needle during initial penetration of the work W; and the lowermost position illustrates the needle as it begins to rise. In Fig. 3 the intermediate or central needle position is illustrated in solid lines and the rim 53 of the stabilizer 53 is shown in the position which it will occupy as the lneedle initially penetrates the work, while the upper and lowermost needle positions are illustrated in dotted lines.

In Fig. 4 the uppermost illustrated position of the needle`23 is shown in solid lines as is the corresponding unflexed position of the needle stabilizer rim 53. The central position of the needle 23' in Fig. 4 is illustrated in dotted lines as is the corresponding position of the stabilizer rim 53. In striking the stabilizer rim prior to penetration of the work, the point `of the needle is shifted or parried slightly to the right as exaggerated 'slightly in Fig. 4, in the interest of clarity. A

corresponding shiftl of the stabilizer rim occurs in the opposite direction. The slight shifting of theneedle under control of the stabilizer has been found to be generally suilicient to eliminate objectionable vibration `which may exist in the slender needle, and accurately to position the needle point just as it enters the Work to insure straight seam formation. In Fig. 4, the lowermost position ofthe needle, which represents the position of the needle as it begins its upward movement.- is shown in dot-and-dash lines. Similar lines have been used to illustrate the corresponding position of the stabilizer rim 53. As this -dot-and-dashiline position illustrates, the needle -is drawn laterally toward the cooperating lower feed-wheel and the presser-wheel 38 by the action of the work on the needle, which lateral drawing effect has lbeen found to occur when certain leathers are being stitched. The flexible needle stabilizer is yieldableto accommodate such -lateralshifting ofthe "needle, kand since suiiicient presser-wheel, the frictional forces between the needle blade andthe stabilizer remain at la very low and unobjectionable value. It will be obvious that if the needle stabilizer was inflexible, the a-ction of the work tending to move the needle laterally toward the roller presser would increase the force with which the needle is pushed or pulled laterally against the inflexible stabilizer. Such in-creased friction, it has been found, is sufficient permanently to bend the needle out of its normally straight form, resulting in a short life of the needle.

I-Iaving thus set forth the nature of the invention, what we claim therein is:

1. A needle stabilizer for a sewing machine having a presser-mechanism including a presserwheel and means supporting said presser-wheel adjacent the path of said needle, comprising a flexible needle deilecting disk adapted to be carried by said presser-supporting means, a rim portion on said disk formed to extend in spaced relation to said presser-Wheel and in the path of said needle.

2. In a sewing machine having an endwise reciprocatory needle and work feeding mechanism including opposed work engaging members, a dish-shaped needle stabilizing disk open toward the needle and having a flexible rim portion disposed for engagement by said needle at the needle penetrating side of the work.

3. In a sewing machine having a vertically reciprocable needle and a Work feeding mechanism including opposed Work engaging members, a vertically inclined needle stabilizing disk supported by one of said opposed work engaging members, said disk having a flexible rim disposed for engagement by said needle.

4. In a sewing machine, stitch-forming mechanism including `a needle reciprocable in a vertical path, opposed work-engaging wheels disposed at one side of said needle path, and a flexible needle stabilizing disk supported -coaxially with one of said wheels, said disk having a rim portion arranged in laterally spaced relation to said coaxial Wheel and extending into the path of said needle.

5. A needle stabilizer for a sewing machine having an endwise reciprocable needle, a feed mechanism and a presser mechanism including a presser-wheel, comprising a sheet metal disk having a, flat central portion, means associated with said central portion for fastening said disk to said presser mechanism in coaxial relation with said presser-wheel, said disk having a frusto conical marginal portion joining said central portion, and a rim formed on the periphery of said frustoconical portion, said rim being disposed in a plane substantially parallel to said central portion and extending into the path of needle reciprocation.

6. In a sewing machine having an endwise reciprocating needle barand work feeding mechanism including opposed work engaging members, a. needle stabilizing disk carried by said work feeding mechanism, said disk having a flexible rim extending into the path of needle reciprocation, and means providing for selective positioning of any of portion of said rim in the path of the needle.

7. In 'a sewing machine having an endwise reciprocating needle bar and work feeding mechanism including opposed work engaging members, a needle stabilizing disk carried by said Work feeding mechanism, said disk having a flexible rim disposed for engagement by said needle, and

means eifective upon operation of the machine for constantly varying the rim portion of said disk engaged by said needle.

8. In a sewing machine having an endwise reJ ciprocatory needle, a feed mechanism, and a presser mechanism including a presser-bar, a stud-shaft carried by said presser bar, and a presser wheel journaled on said stud shaft, a needle stabilizer comprising a sheet metal disk, fastening means securing said stabilizer disk to said stud-shaft in spaced relation to said presserwheel, said disk having a rim portion extending into the path of needle reciprocation.

9. In a sewing machine having an endwise reciprocatory needle, a feed mechanism, and a presser mechanism including a presser-bar, a stud-shaft carried by said presser-bar, a presserwheel journaled on said stud-shaft, and means associated with said stud-shaft for retaining said presser-wheel in predetermined axial position on said stud-shaft, a needle stabilizer comprising a sheet metal disk having a central portion arranged in abutting relation with said presser Wheel, said central portion having an access opening formed therein exposing said presser wheel retaining means, and a rim portion formed on said stabilizer-disk and disposed in spaced relation with said presser-Wheel.

10. A needle stabilizer for a sewing machine having an endwise reciprocable needle, a presser mechanism including a presser-wheel, and means supporting said presser-Wheel adjacent the path of reciprocation of said needle, comprising a needle deflecting member adapted to be secured to said presser-mechanism and including -a portion adapted to extend into the path of needle reciprocation in spaced relation to said presserwheel, said portion being exible transversely of the axis of needle reciprocation.

BERTHOLD P. PINKVOSS. STANLEY J. KETTERER.

References Cited in the le of this patent UNITED STATES PATENTS Number Name Date 207,230 Wensley Aug'. 20, 1878 400,355 Neely Mar. 26, 1889 419,584 Coombs Jan, 14, 1890 1,999,251 Moranville Apr. 30, 1935

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