US1539399A - Looper-driving mechanism for sewing machines - Google Patents

Description

May 26, 1925.

C. W. MUELLER LOOPER muvme MECHANISM FOR SEWING MACHINES Filed April 30. 1925 2 Sheets-Sheet 1 Mania/1 C/za rkw W/Vzze/[m QMOQ M May 26, 1925. 1,539,399

C. W. MUELLER LOOPER DRIVING MECHANISM FOR SEWING MACHINES File April 30, 1923 2 Sheets-Sheet 2 May Patented May 26, 1925.

UNITED STATES PATENT oFFicE.

CHARLES W. MUELLER, OF ST. LOUIS, MISSOURI,,ASSIGNOR, BY MESN'E ASSIGNMENTS, TO LEWIS INVISIBLE STITCH MACHINE 00., A CORPORATION OF MAINE.

LOOPER-DRIVING MECHANISM FOR SEWING MACHINES.

Application filed April 30, 1923. Serial No. 635,459.

To all 107mm it may concern:

' Be it known that I, CrrAnnEs W. MUELLER,

a citizen of the United States, residing at St. Louis, in the State of Missouri, have I invented certain new and useful Improvements in Looper-Driving Mechanism for Sewing Machines, of which the following is a specification.

Sewing machine looper mechanism, particularly for blind-stitch sewing machines, is known wherein a rock-shaft, driven from the main shaft, is employed to impart four of the components of movement to a sixway looper, and an object of my invention is to provide, in the stitch-forming mechanism of a sewing machine, improved means for driving such a rock-shaft controlled looper. An instance of such looper operation including a rock-shaft is found in Patent No. 1,190,833, granted July 11, 1916 to James \Vhitelaw, and in the disclosure of an embodiment of my invention herein, for simplicity, I have illustrated various portions of the mechanism as substantially corresponding with that illustrated in said lVhitelaw patent.

Among the particular objects of my invention are to provide a construction which is susceptible of operation at very high 30 speed, involving only light, simply-constructed parts mounted and cooperating for minimum vibration when very rapidly driven, and arranged for facile adjustment to vary the operative rang of looperanovement imparted from the rock-shaft. Other and further objects will become apparent to those skilled in the art from the following description, taken in conjunction with the accompanying drawings.

To these ends my invention consists in the features of construction and combinations of parts hereinafter set forth and claimed,

In the drawings, Fig. 1 is a front elevation, with parts broken away, of a chainstitch blind-stitcher equipped with loopermechanism embodying my invention; Fig. 2 is a rear elevation of portions of the driving mechanism, and Fig. 3 is a section on line 3-3 of Fig. 1, and Fig. 4 is a section vertically through the parts 38 etc. of Fig. 2.

The frame of the machine is shown as including an upper arm 10 and a lower arm 10, the former having a suitable downward extension 10 to carry a rigid presser foot 11 above which works the stitch-forming mechanism 12, while the lower arm 10" supports suitable work handling and feeding mechanism 13 which need not be described in detail, but which will serve to present the work to the action of the needle 1 1 through a suitable work-aperture in the presser foot 11. Drive shaft 15 extends longitudinally through the upper arm and from it there is driven the rotary cross-shaft or jack-shaft 16, extending through, the frame from front to back, suitable gears 17 and 18 effecting constantly operative connection between the two shafts. A wrist pin 19 on the driven gear 18 is connected by a link 20 with the reciprocable needlebar 21 for which a rock-shaft 22, extending through the frame member 10 serves as a pivotal support, the rocking of the shaft 22 having no operative effect upon the needle bar. The front end of rock-shaft 22, however, has eccentric connection, as by crankpin 23, with the pivot block 24: of a suitable six-way looper element 25, which may be of construction as illustrated in said lVhitelaw patent. The rocking of the shaft 22 will impart four components of motion to the looper element 25, that is tosay, the components of rise and fall and of vibration in the direction of needle travel. To receive the other components of movement, fore-aml-aft across the line of needle travel, the looper structure 25 is pivoted as at 26 to the block 24 and above said block its stem is engaged by a vibratablo lever 27 which is pivoted between at its ends and at its upper end makes engagement by roller 28 with the groove of a face cam 29 mounted on main shaft 15, such arrangement substantially corresponding with that shown in said lVhitelaw patent.

In order to operate the rock shaft 22 very rapidly, as required by high speed running of a machine, time the looper movements to procure a substantial dwell at each end of the vibration of the looper in the direction of needle travel, insure an advantage ous operation of the looper element ditferentiating its speeds of linear travel in dif ferent portions of its excursion, and facilitate adjustment to vary its range of throw, I provide driving mechanism for rock shaft 22 substantially as shown in Fig. 2. Cross shaft 16 has a terminal enlargement 16 from which projects a crank pin 31 carrying a slide-block 32 that operates in the slideway 83 of a lever 3 L which is pivoted as at between its ends. The lower end of this lever is longitudinally slotted as at 36 to receive in adjusted position the stem of a screw 38 which may be secured by nut 39 in any desired adjustment in the slot and which forms a pivot stud for one end of link 40. This link has itsother end pivoted as at 41 to a gear segment 42 of small radius which is pivoted as at 4L3 on av shaft-stub projecting from the frame directly above the shaft 22. The gear segment meshes with a pinion 14 secured on the shaft 22.

Thus, constant rotation of shaft 16 from the main shaft 15 is converted, through the slide block and crank connections 3S31, into a variable-speed reciprocation of lever which is communicated on substantially horizontal line through link to the gear segment 42 which in turn rocks the shaft 22 through its engagementof gear 44. Each of the parts thus provided is relatively small and light, so that reversals of movement may be, accomplished substantially withoutvibration of the machine and without undue wear on the bearings, facilitating very high speed operations, and the vertical alignment of centers of shafts 16 and 35 and of shafts 4-8 and 22, with the disposition of the transfer link 40 to. work always substantially at right angles to such lines of center gives most effective movement to the leverage system involved, minimizes the weight necessary for reasonable safety factor, and gives great freedom of design in the most favorable placement of the shafts in the machine frame, Also the link arrangement described and the adjustable connection of one end thereof at variable distance from the center of oscillation of the part to which it is connected permits quick and facile adjustment of the working throw of the loope-r effected by the roeleshaf t 22.

lVhile I have herein described in detail the particular machine to which my invention is applied and a specific design of the mechanism which I have found satisfactory in operation, it will be understood that changesinay be made in the specific embodiment in matters of detail without de 'iarture from the spirit of my invention within the scope of the appended claims.

I claim:

1. A loopcr driving mechanism fora sewing machine comprising, in combination, a drive shaft, arock shaft, a. loopcr clement mounted to receive four components of motion from said rock shaft, a cross shaft constantly rotatable from said drive shaft, and means for c(nrunnnicating motion from said cross shaft to said rock shaft comprising a pivoted lever operatively connected with, said cross shaft for oscillation thereby, apinion .on the rock shaft, a gear segment meshing with said pinion, and a link connection between said oscillatable lever and said gear segment.

2. In a sewing machine,the combination with a frame, a main shaft mounted therein, accessible at the frontof said frame, a looper. mounted at the front of said frame and having operative front connections with the main shaft for imparting two components of movement to said looper,-a rock shaft connected with said looper for imparting four additional,components of movement thereto, andv connections between said rock shaft and: said main shaft comprising a cross shaft extendingthrough the frame, gearing connecting said main shaft and, cross shaft, a crank on the rear end of said cross shaft, a slide block thereon, lever pivoted to the rear, side of the frame and having a slideway engaged by said block, a pinionca-rried by therock shaft on the rear side of the -fra1ne,a gear segment of small diametermounted on the frame above the: pinion, and agenerally horizontal link con nection between said gear segment and the said lever;

-3.'A structure as set forth in claim '1, wherein the link is at one end connected for adjustment radially to ard the axis of oscillation ofthe parts to which it is connected.

, orianiins w. MUELLER.

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