US2047754A - Sewing machine - Google Patents

Description

A. TIESLER SEWING MACHINE July 14, 1936.

Filed May 21, 1955 2 Sheets-Sheet l vQlffied R'esler wtmmmg A. TIESLER SEWING MACHINE July 14, 1936.

Filed May 21, 1955 2 Sheets-Sheet 2 Patented July 14, 1936 UNITED STATES PATENT OFFICE SEWING MACHINE New Jersey Application May 21, 1935, Serial No. 22,497 In Germany September 21, 1934 6 Claims.

This invention relates to improvements in sewing machines adapted to effect the production of ordinary straightaway seams and seams composed of zigzag stitches of varying amplitude, and

has for its-object to provide improved means for controlling the needle-bar for effecting the seam desired.

More specifically, the present invention aims to provide an improved construction whereby the needle selectively may be caused to vibrate laterally from zero to maximum across the center line of the field of vibration of the needle or from a neutral position at'either side of said field, and whereby the needle selectively may be caused to reciprocate in a neutral or non-vibration path. at the center or at either side of its field of lateral throw.

With the above and other more specific objects in view, the invention comprises the devices, com- 20 binations and arrangements of parts hereinafter described in connection with the accompanying drawings which illustrate a preferred embodiment of the invention, from which the several features of the invention and the advantages attained thereby will be readily understood by those skilled in the art.

In the drawings, Fig. 1 is a front elevation, partly in section, of a sewing machine equipped with a needle-bar controlling device according to 30 the invention. Fig. 2 represents an enlarged section of a portion of the machine bracket arm,

taken substantially in the horizontal plane containing the needle-bar vibrating cam shaft. Fig.

3 is a detail view, partly diagrammatic, of the 35 needle-bar vibrating mechanism, showing in full lines the location of the positioning device for effecting a straightaway seam along a central zero line, and in dotted lines a location of the positioning device for effecting zigzag stitches to 40 both sides of said zero line. Fig. 4 is a detail view, partly diagrammatic, of the needle-bar vibrating mechanism, showing in full lines the location of the positioning device for effecting a straightaway seam in a neutral needle position at the left- 45 hand side of its field of lateral throw, and in dotted lines the location of the positioning device for effecting zigzag stitches to the right-hand side of said neutral position. Fig. 5 is a detail view, partly diagrammatic, of the needle-bar vibrating 50 mechanism, showing in full lines the location of the positioning device for effecting a straightaway seam in a neutral needle position at the righ-hand side of its field of lateral throw, and showing in dotted lines the location of the po- 55 sitioning device for effecting zigzag stitches to the left from said neutral position at the right. Figs. 6 and 7 are detail views representing crosssections of the adjusting shaft and its supporting bushing, with the neutral-position controlling lever included to illustrate positions thereof 5 corresponding with those illustrated in Figs. 4 and 5 respectively.

Referring to the drawings, the sewing machine illustrated therein has a bed-plate I, affording a work-support, from one end of which bed-plate 10 rises the hollow standard 2 of a bracket-arm 3, overhanging the bed-plate and terminating at its free end in a head 4.

Rotatably journaled in suitable bearings provided in said bracket-arm 3 is a horizontally dis-. posed main shaft 5, extending lengthwise of the bracket-arm and carrying at one end a driving pulley 6. At its opposite end, the main shaft 5 carries a counterbalanced crank-arm I provided with a cranl pin 8 connected by a jointed link 9 to a collar l0 suitably'secured upon a vertically disposed needle-bar II.

The needle-bar H carries at its lower end a needle I2 and is journaled for endwise reciprocation in suitable bearings provided in a vibratory gate [3. The gate I3 is pivotally hung upon a screw-stud I4 carried by a supporting member I 5 adjustably threaded into the upper wall of the bracket-arm head 4 to provide for swinging movements of the gate l3 about a pivotal axis transverse to the axis of rotation of the main shaft 5.

Cooperating with the needle l2, below the cloth-plate and in the formation of lock-stitches, is a loop-taker it supported for rotation in a vertical plane parallel to and rearwardly of the plane of needle-vibration. The loop-taker is rotated twice for each complete needle-reciprocation by suitable driving connections with the main shaft 5. Suitable feeding mechanism, as for example of the lower four-motion type, may be provided for advancing work past the needle in a direction transverse to the plane of needle-vibration, and any usual or suitable presser-foot as H may be employed.

Extending horizontally from the lower end of the gate i3 is an arm ll! of which the free end extends externally of the bracket-arm head and carries a pivot-block I9. Embracing the pivotblock I9 is'the forked end of-a rock-arm 20 depending from the front end of a short rockshaft 2i disposed horizontally transverse to the main shaft 5 and suitably journaled at the under side of the bracket-arm head 4. Extending upwardly from the rock-shaft 2| at the rearward side of the head l is a rock-arm 22 of which the free end is connected by a pivot-screw 23 to one end of a bar 24 disposed horizontally and externally at the rearward side of the bracket-arrn 3. Intermediate its ends, the bar 24 is formed with a longitudinal slot 25 receiving a guide-block 26 pivotally secured by a screw 21 to the rear side of the bracket-arm 3.

The other end of the bar 24 is pivotally connected by a shouldered screw 28 to a yoke member 29 which embraces a controlling cam 38 carried by the shaft 3| suitably journaled in the machinearm 3, said shaft 3| being disposed below and horizontally transverse to the main shaft 5. A spiral gear 32 carried by the main shaft drives a spiral gear 33 secured upon the cam-shaft 3|, whereby the latter is rotated at one-half the speed of rotation of the main shaft. From the foregoing, it will be understood that, during the operation of the machine, the cam 39 vibrates the yoke member 29 about the pivot-screw 28, and that the needle I2 performs one complete upand-down movement for each direction of lateral throw of the yoke member 29.

In order to convert the otherwise idle vibratory movements of the yoke member 29 into efiective endwise movements of the bar 24 and consequently to impart vibratory movements to the needle-bar gate l3, the yoke member 29 is provided intermediate its ends with an apertured boss 34 pivotally receiving a shouldered screw 35 threaded into a link 36 pivotally connected by a screw 31 to a crank-arm 38. The crank-arm 38 is fixed to an adjustable fulcrum shaft 39, for example, by means of a set-screw 49, said shaft 39 being rotatably journaled in a bearing sleeve 4| and provided at the front side of the machine with a hand-lever 42. The fulcrum-shaft 39 extends parallel to the cam-shaft 3| and lies approximately in the horizontal plane which contains the axis of rotation of said shaft.

The fulcrum-shaft bearing-sleeve 4| is preferably shiftably supported for lateral movements in the manner more fully shown and described in my prior patent application Serial No. 756,948, filed Dec. 11, 1934. In general, the arrangement comprises securing upon the bearing-sleeve 4| an eccentric 43, as for example by means of a setscrew 44. The eccentric 43 works in a slot 45 formed in a fixed bushing 46 between end walls of said bushing which are provided with parallel guide-slots 41 for the bearing-sleeve 4|. To conveniently effect lateral shifting movements of the fulcrum-shaft 39, the bearing-sleeve 4| is provided at its forward end with an operating lever 48. By operation of the lever 48, the eccentric 43 is rotated and thereby the bearing-sleeve 4| is shifted at an inclination upwards or downwards in the guide-slots 41.

The length of the link 36 between the pivotal axes of the link- screws 35 and 31 is substantially equal to the length of the yoke member 29 between the pivotal axes of the screws 28 and 35. Consequently, if the fulcrum-shaft 39 and the crank-arm 38 carried thereby are in such a position that the pivot-screw 31 is on the line connecting the axis of the cam-shaft 3| and the pivot-screw 23. i. e., if the pivot 31 coincides with the pivot 28, then, in the operation of the machine, the link 36 will perform an oscillatory movement such that the pivot 35 describes a curved path p-p, Fig. 3, concentric with the pivot 28, which latter remains at rest. In this case, no movement is imparted to the needle-bar gate I 3 and there is eifected a straightaway seam located in a zero line centrally of the lateral throw of the needle when the latter is vibrated.

If the fulcrum-shaft 39 is now turned to its opposite limit of movement by operation of the hand-lever 42, thereby inclining the crank-arm 38 as illustrated by dotted lines in Fig. 3 of the drawings, the pivot 31 is no longer on the line connecting the axis of the cam 30 with the pivot 23, and the pivot 35 will, due to vibration of the yoke 29, describe an arc p'-p', between the points rr thereof, said arc being concentric with the pivot 31. The bar 24 will be now reciprocated, so that the needle-bar gate I3 is vibrated to effect a zigzag seam extending equal distances to both sidesof said zero line (Fig. 3). The amplitude of lateral movement of the needle is of course dependent upon the extent of turning movement imparted to the fulcrum-shaft 39 and may be varied at will by manipulating the handlever 42.

As hereinbefore described, the fulcrum-shaft 39 is adapted to be shifted bodily upward and downward in an inclined path, the path of shifting movement of said shaft corresponding approximately with the arc p'--p', Fig. 3.. If the fulcrum-shaft 39 is so angularly adjusted that the pivots 28 and 31 are in alinement, then, on the bodily downward shift of the shaft 39 from r to r', the yoke member 29 and the bar 24 will be shifted endwise as illustrated in Fig. 4, so that the needle I2 is displaced to the left of its central zero position. In consequence of said shift of the fulcrum-shaft 39 with the crank-arm 38 fixed thereto, the are 12-12 of Fig. 3 is shifted to p p Fig. 4. Further, as the arc 11 -1) is concentric with the pivots 28 and 31, no endwise reciprocatory movements will be transmitted to the bar 24 and consequently no vibration will be imparted to the needle-bar gate l3 in the operation of the machine. There is accordingly effected, as shown in Fig. 4, a straightaway seam in a line located to one side, i. e., the left-hand side, of the first mentioned zero line.

If the fulcrum-shaft 39 be shifted its maximum distance downward to 1", as above explained, and also turned angularly to its maximum extent to incline the crank-arm 38 relatively to the pivot 28, as illustrated by dotted lines in Fig. 4, the arc M is again shifted to p'--p'. As 1' lies at the point of intersection of the arcs p'--p and zF-p in the position of maximum inclination of the crank-arm 38, for sewing the maximum width 01 zigzag seam, and determines the end position of the pivot 35, the bar 24 is reciprocated in the operation of the machine to vibrate the needle-gate l3 to one side only of its left-hand neutral or zero position. The amplitude of needle-vibration between zero and maximum is of course dependent upon the degree of turning movement imparted to the fulcrum-shaft 39.

Referring now to Fig. 5 of the drawings, it will be observed that when the center of the fulcrumshaft 39 is shifted upwardly to r, the yoke member 29 and thus also the bar 24 will be shifted endwise in a direction to shift the neutral path of needle-reciprocation, i. e., the straightaway stitches, to the right of its central zero position. In this neutral position of the needle, the pivots 28 and 31 may be again in alinement, so that the pivot 35 describes an arc 12 -12 If a maximum turning movement be now imparted to the fulcrum-shaft 39, the arc p p is again shifted to coincide with the arc p-p', whereby vibratory movements are imparted to the needle to one side only of its right-hand neutral position.

It is to be noted that while the neutral position of non-vibration of the needle may be changed by manipulation of the controlling mechanism above described, the points r'r= of the arcs p'p', illustrated in Figs. 3, 4, and 5 of the drawings, are coincident. Consequently the field of maximum lateral vibration of the needle i2 remains constant, regardless of the neutral or zero position of the needle. Furthermore, as the pivots 28 and 31 are coincident in the several neutral positions of the needle l2, the latter is reciprocated in a definitely fixed path in each of said neutral positions.

Having thus set forth the nature of the invention,-what I claim herein is:-

1. Needle-vibrating mechanism for zigzag sewing machines comprising, a vibratory gate, a rotary cam, a yoke member deriving lateral vibratory movements from said cam about a pivotal axis connected to vibrate said gate, a link pivotally connected to said yoke member, and an adjustable fulcrum for said link shiftable into and out of substantial coincidence with the pivotal axis of said yoke member.

2. Needle-vibrating mechanism for zigzag sewing machines comprising, a vibratory gate, a rotary cam, a yoke member deriving lateral vibratory movements from said cam about a pivotal axis connected to vibrate said gate, a link pivotally connected to said yoke member, an angularly adjustable crank-arm, and a pivotal connection between said link and crank-arm shiftable into and out of substantial coincidence with the pivotal axis of said yoke member by turning movements of said crank-arm.

3. Needle-vibrating mechanism for zigzag sewing machines comprising, a vibratory gate, a rotary cam, a yoke member deriving lateral vibratory movements from said cam about a pivotal axis connected to vibrate said gate, a link pivotally connected to said yoke member, an angularly adjustable crank-arm, a pivotal connection between said link and crank-arm shiftabie into and out of substantial coincidence with the pivotal axis of said yoke member by turning movements of said crank-arm, and supporting means for said crank-arm providing for adjustment of the axis of turning movement thereof.

4. Needle-vibrating mechanism for zigzag sewing machines comprising, a vibratory gate, a rotary cam, a yoke member deriving lateral vibratory movements from said cam about a pivotal axis connected to vibrate said gate, a link pivotally connected to said yoke member, and a fulcrum for said link, said link having an effective length substantially equal to the distance between the pivotal axis of said yoke member and the point of connection of said link to said yoke member.

5. Needle-vibrating mechanism for zigzag sewing machines comprising, a vibratory gate, an endwise movable bar connected to vibrate said gate, a rotary cam, a yoke member pivotally connected to said bar and deriving lateral vibratory movements from said cam, a link pivotally connected to said yoke member and having an effective length substantially equal to the distance between the points of connection of the yoke member to the bar and to the link, a fulcrum-shaft disposed substantially parallel with the axis of rotation of said cam, and a crankarm carried by said shaft providing a fulcrum for said link.

6. Needle-vibrating mechanism for zigzag sewing machines comprising, a vibratory gate, an endwise movable bar connected to vibrate said gate, a rotary cam, a yoke member pivotally connected to said bar and deriving lateral vibratory movements from said cam, a link pivotally connected to said yoke member and having an effective length substantially equal to the distance between the' points of connection of the yoke member to the bar and to the link, a fulcrum-shaft disposed substantially parallel with the axis of rotation of said cam, a crank-arm carried by said shaft providing a. fulcrum for said link, and supporting means providing for bodily lateral adjustment of said shaft in a path inclined to the path of reciprocationof said bar.

ALFRED TIESLER.

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