US2895442A - Work table height adjusting mechanism for blindstitch sewing machines - Google Patents

Description

Jl'y 21, 1959 F. PARRY 2,895,442 woRx TABLE: HEIGHT ADJusTING MECHANISM FOR l BLINDsTIIcH SEWING MACHINES Filed Nov'. 14, 1955 2 Sheets-,Sheet 1 .//vvE/vron, .Fran/r Parry By wia/wn July `21, 1959 Y F. PARRY 2,895,442 WORK TABLE HHIGH'I` ADJUSTING MECHANISM FORv 4 BLINDSTITCH SEWING MACHINES Filed Nov. 14, 1955 2 Sheets-Sheet 2 lllllllllllluw I y A WE/vm? Y I l F ran/r Parry w/r/vfss By T ORA/E Y Unid WORK TABLE HEIGHT ADJUSTING MECHANISM FR BLINDSTITCH SEWlNG MACHINES Frank Parry, rlrurnlnrll, Conn., assigner to The Singer Manufacturing Company, Elizabeth, NJ., a corporation of New Jersey Application November 14, 1955, Serial No. 546,55e

3 Claims. (012112-260) This invention relates to sewinggmachnes and, more particularly, to mechanism for controlling the elevation of the work supporting table of a blindstitch sewing machine.

It is an object of this invention to provide a positive stop `defining the upper limit of work table movement in a `blindstitch machine.

Another object of `this invention -is to provide a work table elevation controlling device for a blindstitch sewing machine with which either a wide range of adjustment or a iine micrometer adjustment of work table elevation may be made with equal facility.

Withthe above and other objects and advantages in view, as will hereinafter appear, this invention comprises the devices, combinations, and arrangements of parts hereinafter described and illustrated in the accompanying drawings of a preferred embodiment thereof in which:

Fig. l represents a vertical sectional View of a machine constructed in accordance with my invention taken longitudinally of the base and through the standard and work table and having portions of the ridge former actuating mechanism broken away to expose the work table height adjusting mechanism.

Fig. 2 is an enlarged view of a portion of the sewing machine of Fig. 1, showing the base portion of the machine frame taken in cross-section substantially along line 2-2 of Fig. l and having parts of the machine frame broken away to expose the work table height adjusting mechanism.

Fig. 3 represents a cross sectional view taken substantially along line 3-3 of Fig. 2.

Referring to the drawings, this invention is illustrated as it is applied to a :blindstitch sewing machine of the type having a frame including a base 11, a standard 12 rising from the base, a bracket arm 13 extending laterally from the standard and a sewing head 14 projecting forwardly from the bracket arm.

Fixed Iwith respect to the sewing head 14 is a presser foot 15 against the under surface of which the fabric to be stitched is adapted to bear. The presser foot is formed in a conventional manner with an aperture (not shown) through which a ridge of fabric is adapted to be forced upwardly and into the path of travel of a curved needle 16 carried in the sewing head. Also carried in the sewing head is a looper 17 cooperating with the needle in the formation of chain stitches, and a work feeding member 18 provided with a serrated work engaging lower surface 19 adapted to extend downwardly through slots formed in the presser foot 15 into engagement with the work fabrics.

The work fabrics are carried beneath the presser foot on a work supporting table 21 which is pivotally supported in the usual manner on a pivot pin 22 carried in a bracket 23 secured on the front end of the machine base 11. The work supporting table 21 is also formed with a front skirt 24 to which a coil spring 25 is connected `by means of a pin 26. The coil spring extends rearwardly into the machine bed and is secured to a stud bolt 27 fastened in the rear wall of the base 11 and by which the coil spring is tensioned so as to urge the work table in a counterclockwise direction about the pivot pin 22 and `thus to urge the work. supporting table toward the presser foot.

Carried beneath the work table 21 is a ridge forming mechanism indicated generally as 28. The ridge former mechanism may be of any conventional type actuated by operable connections extending through the frame and driven by drive shafts 29 and 30 in the bracket arm 13. This mechanism may, for instance, be of the type disclosed in my U.S. Patent No. 2,743,688, May 1, 1956, to which reference may `be had for a complete disclosure thereof. The ridge forming mechanism includes a ridge former 31 which operates to` force a ridge of the work fabrics upwardly through an aperture in the presser foot and into the path of the curved needle 16. The extent to `which the ridge former forces the fabric upwardly through the presser foot 15 determines the depth or extent of needle penetration of the fabrics. In the machine of the present invention the extent of ridge former effectiveness is determined by means of a mechanism for limiting the proximity of the work supporting table 21 to the presser foot 1S; thus the nearer the table 21 is permitted to approach the presser foot, the more effective the `ridge former becomes.

Referring more particularly to Fig. l, movement of the work supporting table 2.1 in a `counterclockwise direction and toward the presser foot 15 is limited by a stop member in the form of a stop lever 32 which is fulcrumed upon the work table pivot pin 22 and is formed with a short depending stop arm 33 disposed to abut the front skirt 24E ofthe work table. The stop lever 32 is formed with an arm 3ft which extends rearwardly within the machine base and is slot-ted,` as at 35, at its free extremity to straddle a shoulderedpivotscrew icarriedby a threaded stud 37. The stud 37 forms a part of a control device which serves to determine the position of the stop lever 32 and hence of the upper limit of work support movement. The stud 37 threadedly engages a control member `which takes the form of a rod 3S journaled for both turning and endwise sliding movements in the machine frame. The rod 38 is threaded, as at di), to accommodate the stud 37 and is formed between its ends with a plurality of annular serrations si shaped in the form of gear teeth to provide a rack lengthwise of the control member. Meshing with the gear tooth-shaped serrations 41 is a gear segment i2 fast on the stud shaft 43 journaled in a bushing 44 secured to the fro-nt wall of the machine standard 12. The stud shaft d3 has secured thereto, exteriorly of the machine frame, a hand lever 45 which extends into the space between the standard 12 of the machine frame and a plate 46 which is supported in spaced relation to the standard by means of fastening screws 47--47 and a spacing block 4S. An arcuate slot 49 formed in the plate i6 accommodates a stud bolt Sil fixed in the hand lever d5 and threadedly engaging a `clamp nut 51 by which the hand lever may be turned within the range of movement provided lby the arcuate slot 49. By tightening the clamp nut 51, the hand lever may ybe locked with respect to the machine frame in any selected position along the arcuate slot 49.

When the hand lever i5 is turned, the gear segment 42 imparts endwise sliding movement to the rod 38 and with it to the stud 37 which by way of its slidingly pivotal connection 35-36 with the stop lever arm 34 effects a relatively large adjustment of the stop lever position. The hand lever 4-5, therefore, provides a means for the machine operator to eifect rapid adjustment of the work table height to any selected position within the permissible range of adjustments. Such rapid adjustment is Patented July 21, 1959 advantageous, for instance, when the machine is called upon to sew a completely different weight or thickness of fabric.

There is also the need in this type of blindstitch machine for a means to effect an exceedingly ne or micrometer adjustment of the work table height, as when adjusting the machine to sew, for instance, through only one of a plurality of plies of fabric. In the construction of the present invention such micrometer adjustment of work `table height may be accomplished in any position of the hand lever 45 fby tightening the clamp nut 51 which acts to restrain the control member or rod 38 against endwise movement in the frame, and then by turning the control rod by means of a hand wheel 52 secured to its free extremity. The threaded connection between the control rod 38 and the threaded stud 37 provides, in effect, a turnbuckle, and since the control rod is restrained against endwise movement, turning of the rod will effect a tine micrometer adjustment of the position of the stop member 32, and hence, of the Work table height. Y

Having thus described the nature of the invention, what I claim herein is:

1.r A work table height adjusting mechanism for a blindstitch sewing machine having a frame, comprising a work table stop member shiftably supported on said frame, a threaded stud operatively associated with said stop member, a control rod rotatably journaled in said frame, said control rod being threaded axially to accommodate said threaded stud, operator influenced means for turning said control rod, a series of axially spaced annular gear tootheshaped serrations formed on said control rod providing an annular rack thereon, a gear carried for turning movement in said frame and disposed in mesh with said annular rack, operator influenced gear turning mechanism carried by said frame, and means for clamping said gear turning mechanism rigidly to said frame in any selected position of adjustment thereof.

2. A work table height adjusting mechanism for a blindstitch sewing machine having a frame, comprising a Work table stop member shiftably supported on said i frame, a threaded stud operatively associated with said stop member, a control rod rotatably journaled in said frame, said control rod being threaded axially to accommodate said threaded stud, operator inuenced means for turning said control rod, a series of axially spaced annular gear tooth-shaped serrations formed on said control rod providing an annular rack thereon, a shaft journaled in said frame transversely of said control rod, a gear fast on said shaft within said frame and disposed in mesh With said annular rack, an arm constituting a handle fast on said shaft exteriorly of said frame, and clamp means effective to secure said handle in any selected position with respect to said frame.

3. A work table height adjusting mechanism for a blindstitch sewing machine having a frame, comprising a work table stop member shiftably supported on said frame, a threaded stud operatively associated with said stop member, a control rod rotatably journaled in said frame, said control rod being threaded axially to accommodate said threadedvstud, operator influenced means for turning said control rod, a series of axially spaced annular gear tooth-shaped serrations formed on said control rod providing an annular rack thereon, a shaft journaled in said frame transversely of said control rod, a Kgear fast on said shaft within said frame and disposed inmesh with said annular rack, an arm constituting a handle fast on said shaft exteriorly of said frame, a plate projecting from said frame and associated rigidly therewith, said plate being formed with an arcuate slot having its center of curvature coincident With the axis of said shaft, a threaded pin carried by said handle and disposed to extend through said arcuate slot, and a clamp nut carried on said threaded pin at the side of said plate opposite said handle.

References Cited in the le of this patent UNITED STATES PATENTS 745,736 Onderdonk Dec. 1, 1903 1,689,846 Woodcock Oct. 30, 1928 2,514,837 Buono July 11, 1950

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