US2242688A - Automatic material holdback foot attachment for sewing machines - Google Patents

Description

May 20, 1941. M ER 2 2,242,688

AUTOMATIC MATERIAL HOLDBACK FOOT ATTACHMENT FOR SEWING MACHINES Filed March 15, 1940 4 Sheets-Sheet 1 yeyer finger May 20, 1941. U 4 2,242,688

AUTOMATIC MATERIAL HOLDBACK FOOT ATTACHMENT FOR SEWING MACHINES Filed March 15, 1940 4 Sheets-Sheet 2 n n Q5 0 (I) Q I J n I u I a, l 4 k!- N Meyer [/uger M. UNGER May 20, 1941.

AUTOMATIC MATERIAL HOLDBACK FOOT ATTACHMENT FOR SEWING MACHINES 4 Sheets-Sheet 3 Filed March 15, 1940 M a M. S M a M 5 I c w a a 1- x fl I G 6 9 a 7 6 5 5 5 5 J 5 n 5 n May 20, 1941. M NER 2,242,688

AUTOMATIC MATERIAL HOLDBACK FOOT ATTACHMENT FOR SEWING MACHINES grwwvtom Hagar finger Patented May 20, 1941 UNETED TENT OFFICE AUTOMATIC MATERIAL HOLDBACK FOOT ATTACHMENT FOR SEWING MACHINES 18 Claims.

This invention relates to an automatic material hold-back foot attachment for sewing machines.

In garment industries and in the use of sewing machines manually controlled in their operation, it has heretofore been the practice of hold back the material, for it frequently hap-- pens that the fingers of the operators are injured by the sewing machine needle. Also by eifecting the holding back of the feed of the material being sewed by the foregoing method, there is no assurance that the fingers of the operator can accomplish the desired results because in many instances the retarding pressure exercised by the operator may be unintentionally relieved and result in stretching of the material while being sewed upon.

In the sewing of materials, especially light flimsy materials and in sewing on the bias, there is a tendency by the operator to clear the bed plate or table of the machine of the sewed material rearwardly of the presser foot and this clearing action on the material is accomplished by pushing or shoving the material rearwardly of the presser foot which exerts a strain on the sewed material and stretches the same, especially those materials sewed on the bias. In the sewing of materials of considerable length, the weight of the material passed beyond the presser foot and falling from the bed plate or table of the machine exerts a pulling strain on the sewed material and tends to stretch the same rearwardly of the presser foot.

It is therefore the primary object of this invention to provide an attachment for a sewing machine of any type which may be attached to a sewing machine and be automatically controlled in its operation to hold back th feeding of the material and prevent stretching thereof while being sewed, the attachment being of such character that the same may be rendered inoperative to permit the sewing machine to be used in ordinary sewing operations.

A further object of the invention is to provide an automatic material hold-back foot attachment for sewing machines that is associated with the usual sewing machine presser foot and positioned post-adjacent thereto, being capable of adjustment with respect to the presser foot and having devices for the operation thereof operatively engaged with a movable element of the usual sewing machine mechanism, the automatic hold-back foot being operative to prevent the free feeding of the material rearwardly of the presser foot and causing the material to be puckered, gathered or bunched between the holdback foot and the presser foot for a regular number of regular sewing machine stitches with devices operative for automatically raising the hold back foot to permit the escape of the sewed material with the hold-back foot immediately thereafter lowered into its operative material holdback position.

It, is a further object of the invention to provide an automatically operating material hold back foot of the foregoing character wherein the tension on the hold-back foot may be varied to accommodate its use with materials of different kinds such as silks, linens, voiles, cottons, rayons, or heavy materials such as woolens or jerseys or the like.

With the above and other objects in View that will become apparent as the nature of the invention is better understood, the same consists in general of certain novel details of construction and combination of parts hereinafter more fully described, illustrated in the accompanying drawings and claimed.

In the accompanying drawings:

Figure 1 is a side elevational view of a sewing machine constructed in accordance with the present invention, the stand being omitted and showing the automatic material hold-back foot attachment therefor,

Figure 2 is a bottom plan view of the sewing machine showing a part of the operating mechanism for the material hold-back foot,

Figure 3 is an outer end elevational View of the head of the sewing machine showing the vertically reciprocating needle, the vertically adjustable presser foot, and the vertically movable automatic material hold-back foot attachment, the latter being illustrated as variably tensioned and the device for'holding the hold-back foot 7 the material hold-back foot is elevated to its material releasing position,

Figure 5 is a fragmentary longitudinal sectional View taken on line 5--5 of Figure 4,

Figure 6 is a detailed cross-sectional view taken on line 6-6 of Figure 5, showing a brake device permitting rotary movement of one of the clutch elements in one direction only,

Figure 7 is a detailed sectional View taken on line '|l of Figure 5, showing a brake or clutch device permitting movement of the other clutch element in one direction only.

Figure 8 is a fragmentary outer end elevational view of the head of the sewing machine with the automatic material hold-back foot in its lowered, operative position and showing the sewed material gathered between the presser foot and the hold-back foot,

Figure 9 is a fragmentary elevational view, similar to Figure 8, showing the material holdback foot elevated with the gathered or bunched material projected rearwardly thereof and in semi-gathered formation, and

Figure 10 is a fragmentary elevational view,

partly in section, of the material hold-back foot and the supporting guide therefor.

Referring more in detail to the accompanying drawings, a sewing machine of standard construction is illustrated and comprises a bed plate I5 from one end of which rises the usual hollow upright [S that carries at its upper end a horizontally extending overhanging hollow arm H that carries at its free end above the bed plate I5 a head i8. A horizontal drive shaft I9 extends through the upper end of the upright l6 and the overhanging arm ll, one end of the rive shaft projecting from the upper end of the upright and carrying the usual flywheel 2i! and drive belt sheave 2|, the other end'of the drive shaft is being operatively engaged with the vertically sliding bar 22 in the head l8 that carries the needle 23 at its lower end. The vertically sliding bar 24 in the head I8 carries the presser foot 25 at its lower end that engages the throat plate 26 of the bed plate l5, these devices being common to sewing machines of standard construction. The vertically movable bar 24 that carries the presser foot 25 at its lower end has a laterally directed abutment adjacent its upper end as shown at 21, said abutment projecting outwardly of the head 18 as shown in Figure 3 for engagement by the cam lever 23 pivotally mounted upon the stub shaft 29 having a threaded end 39 to facilitate mounting of the shaft in the head i8.

The automatically operating material holdback foot attachment for the sewing machine as shown more clearly in Figures 1, 3 and 8 to 10 comprises a vertically shiftable rod 3| vertically slidable in the tubular guide 32 carried by the stub shaft 29 and extending across the end of the latter, the rod 3! carrying a cross pin 33 having projecting ends extending through diametrically opposite slots 34 in the upper end of the tubular guide 32 to restrain rotative movements of the rod 31 in the tubular guide but permitting sliding movements thereof. The lower end of the rod 3! is threaded as at 35 for the adjustable threaded reception of the material hold-back foot 36 retained in adjusted position thereon by means of the set screw 3?. As shown in Figure 3, the hold-back foot 35 is post-jacent the presser foot 25, and while illustrated as being directly tive to the presser foot may be made. It will also be observed that a pocket area 36 is formed between the rear end of the presser foot 25 and the forward end of the hold-back foot 33 which permits the gathering of the material being sewed therein. A support is provided for the upper end of the rod 3 l and to vary the tension of the holdback foot 36 in its engagement with the material, the rod 3| below the lower end of the tubular guide 32 is surrounded by a coil spring 38, the upper end of which engages the lower end of the tubular guide while the lower end of the spring is engaged by a nut 39 adjustably threaded on the lower end of the rod 3 i.

The supporting means for the upper end of the rod 3| of the hold-back foot is shown more 'clearly in Figure 1 and comprises a lever arm pivotally mounted as at on the outer side of the overhanging arm i1, one end 4! of the lever arm extending toward the head l8, while the other end 42 extends toward the upright E6. The free end of the lever arm 4! carries an end extension pin 43 that freely passes through a slotted opening 44 in a head 45 at the upper end'of the rod 3! as shown in Figures 1 and 3. 'The free end of the lever arm 42 has pivotally connected thereto as at 45 the upper end of a link rod 41, with the lower end of the link rod 4'! as shown more clearly in Figures 1, 4 and 6 being bent at right angles to provide a hook 48 that is pivotally engaged with one end of the lever 49 pivoted intermediate its ends as at 56 on a lug 5| depending from the bed platel5, the lever 39 being adapted for operation by the knee of the operator for moving the lever arms M and 42 for the elevation of the material hold-back foot 36 when it is desired to manually raise the same. The link rod 41 is'norm'ally held at its limit of upward movement while the rod 31 carrying the hold-back foot 36 is normally held at its limit of downward movement by means of the coil spring 38 interposed between the stationary tubular guide 32 and the nut as adjustable on said rod 3!. When the presser foot 25 is elevated fromthe throat plate 26 by the cam lever 28, the abutment shoulder 25 on the upper end of the presser foot 25 engages the nut 39 upon the rod 3| to held by the latch 52 shown more clearly in Figures 1 and 3 as being pivoted at one end as at 53 on the head 8 with an operating handle 54 carried by its other end, the latch 52 being en- 'gageable with the underside of the pin extension 43 carried by the lever arm 4! for elevating the latter as will at once be apparent from an inspection of said figures.

in standard constructions of sewing machines,

the drive shaft I9 is operatively engaged with a series of rocker shafts and other shafts for i the operation of the vertically reciprocating bar 22 carrying the needle, the material feeding shoe and also for the shuttle 55 disposed beneath the throat plate 26, rocker shafts being indicated in Figures 2, 4 and '5 by the reference characters 53 and 51, the rotatable shaft 58 operating'the shuttle 55. Mechanism for the automatic operation of the hold-back foot attachment is illustrated as bpaaavay engaged with the rocker shaft 51, the latter having a laterally directed arm 51 shown in Figure 2, to the outer end of which a link rod 59 is pivotally attached as at 59, the link rod 59 being fragmentarily illustrated in Figures 4 and 5 with the other end of the link rod operatively connected to the drive shaft 19. A bracket plate 68 is illustrated as being vertically disposed and extending transversely subjacent the bed plate 55 and carries at its upper end a horizontal flange 6| that is bolted as at 62 to the bottom face of the bed plate 15, the bracket plate Ell providing a support for the operating devices for the material hold-back foot. A shaft 53 extends longitudinally of the bed plate I5 through the bracket plate 69, the latter carrying a support 64 at one side thereof for said shaft 63 with the shaft anchored in the support against rotation as at 65. A clutch device is associated with the shaft 63 at the side thereof opposite the support 64 and said clutch device includes a collar 66 rotatable on the shaft 63 latero-J'acent the bracket plate (ill, the collar 65 carrying a peripherally projecting cam lug Bl. A clutch disk 68 rotatable on the shaft 63 has an interfitting abutting connection with the collar 66 and is secured thereto by the radial screw pins 69. A cooperating clutch disk H! has an interfitting facial connection with the clutch disk 68, said interfitting connection comprising overlapping shoulders H and 12 as clearly shown in Figure 5. The outer face of the clutch disk H3 is provided with a transversely extending undercut groove l3 and said clutch disk it is maintained in assembled relation with the clutch disk 58 by means of the headed end screw i l threaded through the bottom wall of the undercut groove 13 and entering the adjacent end of the shaft 63.

As shown more clearly in Figure '7, the shouldered portion H of the clutch disk is provided with a cam groove or pocket 15 facing the uninterrupted peripheral surfaces of the shouldered portion 52 of the clutch disk 68, the cam mit rotation thereof in one direction and to restrain rotation in the opposite direction and, as shown in Figure 6, comprises a holder 11 mounted upon the bracket plate Bil, the holder ll supporting a wedge plate 18 with a ball or roller 19 interposed between the Wedge plate 18 and the peripheral surface of the clutch disk 68, said wedging ball or roller 79 being retained in its operative position as illustrated in Figure 6 by means of a cover 80 secured to the holder 17, said cover 80 having an opening therein housing a coil spring engaged with the ball or roller '19 and in turn engaged by the screw 8| threaded through the outer end of the cover 80.

Oscillatory movements are imparted to the clutch disk 10 through operative connections with the rocker shaft 51 which include, as shown in Figures 2 and 4, an arm 82 fixed at one end to the rocker shaft 5'! with the arm extending across the outer face of the clutch disk 70 and being longitudinally slotted as at 83 with a pin 84 that is radially adjustably mounted in the undercut groove 13 extending into said slot.

As shown more clearly in Figures 4 and 6, a screw pin 85 is secured in the bracket plate 60 and pivotally supports a bell-crank lever having lever arms 86 and 81, the lever arm 86 havin 7 its free end disposed in the path of rotary movement of the cam lug 61 on the collar 66 while the outer end of the other lever arm 81 has an opening therein for the passage of a rod 88, the lower end of which is threaded as at 89 for the reception of the thumb nut that is engaged with the lower side of the lever arm 81, while the upper end of the rod 88 carries a hook 9| for engagement with the hook 48 at the lower end of the link 'rod 41. By adjusting the nut 90 on the rod 88, the effective position of the free end of the lever arm 85 relative to the cam lug 61 may be varied, different adjustments providing for the degree of vertical lift of the material hold-back foot 36 to compensate for different thicknesses of material being sewed.

From the above detailed description of the invention, it is believed that the construction and operation thereof will at once be apparent, it being noted that during the operation of the sewing machine with the material hold-back foot lowered into material-engaging position as shown in Figure 8, the material feed with the feed' dog beneath the presser foot is held back by said foot 36 to the exclusion of. the hands of the operator, the material being illustrated in Figure 9 by the reference numeral as entering beneath the presser foot 25 While the stretched or sewed material is illustrated in Figure 8 in a gathered or bunched.- condition as at 95 within the pocket 36 between the presser foot 25 and the hold-back foot 36. Thisactio-n of the hold-back foot 36 relieves any pulling strains on the material 85 and eliminates the practice of the operator using the fingers of the hand to retard the feeding of the material, the hold-back foot 36 being operative to prevent stretching of the material, especially light flimsy materials or materials that are being sewed on the bias. During the operation of the sewing machine the rocker shaft 51 imparts a swinging movement to the slotted arm 82 and said arm 82 oscillates the clutch disk 10 as will be apparent from an inspection of Figure 4, this motion of the clutch disk 10 is imparted to the clutch disk 68 through the medium of the cam pocket 15 and the wedging ball or roller 16 shown therein in Figure 7, one rotary direction of movement of the clutch disk ll] carrying the clutch disk 68 in a like direction of rotary movement, the wedging devices l5 and 16 preventing rotary movement of the clutch disk 18 in the opposite direction relative to the clutch disk 68. To prevent retrograde rotation of the clutch disk @8, the wedging device 19 shown in Figure 6 is engaged with said clutch disk 68, but is operative to permit rotary movement in one direction of the clutch disk 68 under influence of the clutch disk 10. The rocker shafts and the driving shaft [9 for the needle carrying bar 22 are so timed that with each reciprocation of the needle shaft for the sewing of a stitch effects one step rotary movement of the collar 66 fixed to the clutch disk 68 and after a predetermined number of stitches .have been sewed the cam lug 61 upon the collar 66 moves into engagement with the bell-crank lever arm 85 for pulling downwardly on the rod 88 by means of the lever arm 81, the link rod 4! for operating the two-armed lever 4|42 for the elevation of the rod 3! carrying the material hold-back foot 36. When the hold-back foot 36 is elevated as shown in Figure 9, the bunched material illustrated at $35 in Figure 8 automatically escapes through inherent tension in the bunched material and assumes the gathered formation 95 shown in Figure 9. This gathered formation is serviceable in uniting bias and similar seams, especial-l-y in arm-hole work on garments and if the gathering formation 95* is not desired, the material may be easily flattened and restrained against stretching activities by the line of stretching in the material. The number of stitches sewn between the rise and fall of the hold-back foot 3% may be varied by adjusting the pin 84 longitudinally of the clutch disk groove 13 and the slot 83 in the arm 82, the tension of the hold-back foot 36 being adjusted by the nut 39 on the rod 3|, the angularity of the hold-back foot being adjustable relative to the presser foot 25 while the degree of lift of the hold-back foot 36 is adjusted by means of the nut 96 shown in Figres 4 and 6 as threaded upon the lower end of the rod 88 that has its upper end engaged with the link rod 41.

When the cam lever 28 is operated for raising the presser foot- 25, the hold-back foot 35 is automatically raised therewith and when it is desired to use the sewing machine to the exclusion of the hold-back foot, the latch 52 engage the pin 43 at the free end of the lever arm 4| to elevate ie rod 3i carrying the hold-back foot 36. The hold-back foot 36 may be elevated by means of the knee cperated lever 49.

While there is herein shown and described the preferred embodiment of the invention, it is to be understood that various changes may be made therein, such as will come within the scope of the invention as claimed, it being further understood that the mechanism disclosed herein is only one embodiment of the invention to accomplish the automatic hold-back of the material while being sewed upon to prevent stretching activities of the material and to prevent injury to the hands of the sewing machine operators.

I claim:

1. In combination with a sewing machine having the usual sewing needle and presser foot and reciprocating carrying bars therefor, operating. means for the bar carrying the needle, an automatically operated material hold-back foot postjacent the presser foot and normally positioned to prevent passage of. material passed rearwardl'y of the presser foot and means operated at intervals following a predetermined multiple number of reciprocatory movements of the bar carrying the needle to raise the hold-back foot to release the held material.

2. In an automatic material hold-back foot attachment for sewing machines, wherein the sewing machine includes a presser foot having an associated cam lifting lever, a material feeding dog and operating means for the dog, said attachment including a tensioned hold-back foot postjacent the presser foot and normally lying in the operative plane of the presser foot to hold back and prevent stretching of the sewed material passed rearwardly of, the presser foot and devices interposed between the tensioned} holdback foot and said operating means and operated by the latter to effect raising of the hold-back foot at predetermined intervals following a predetermined multiple number of reciprocatory movements of the bar carrying the needle to raise the hold-back foot torelease the sewed material held back by said tensioned" hold-back foot.

3. An automatic material hold-back foot attachment for sewing machines as set forth in claim 2, wherein a vertically shiftable rod carries the hold-back foot and said devices include a series of links and levers with one end of a lever engaged with the upper end of the rod.

4. An automatic material hold-back foot attachment for sewing machines as set forth in claim 2, wherein a vertically shiitable rod carries the hold-back foot and said devices include a series of links and levers with one end of a lever engaged with the upper end of the rod, and an obstruction on said rod adapted to be engaged by said presser foot whereby the hold-back foot may be manually raised when the cam lever is operated for raising the presser foot.

5. An automatic material hold-back foot attachment for sewing machines as set forth in claim 2, wherein a vertically shiftable rod carries the hold-back foot and said devices include a series of links and levers with one end of a lever engaged with the upper end of the rod and means for holding the hold-back foot in elevated inoperative position.

6. An automatic material hold-back foot attachment for sewing machines as set forth in claim 2, wherein a vertically shiftable rod carries the hold-back foot and said devices include a series of links and levers with one end of a lever engaged with the upper end of the rod, and an obstruction on said rod adapted to be engaged by said presser foot whereby the hold-back foot. may be manually raised when the cam lever is operated for raising the presser foot and means for holding the hold-back foot in elevated inoperative position.

7. An automatic material hold-back foot attachment for sewing machines as set forth in claim 2, wherein said devices include adjustable means to vary the height of raising movement of the material hold-back foot.

8. An automatic material hold-back foot attachment for sewing machines as set forth in claim. 2, wherein said devices include clutch elements operative in one oscillatory rotative direction of travel, a cam lug carried by one of said clutch elements, a series of links and levers with one end of a lever connected to the holdback foot and the end of another lever being in the path of said cam lug for operation thereby to raise the hold-back foot.

9. An automatic material hold-back foot attachment for sewing machines as set forth in claim 2, wherein said devices include clutch elements operative in one oscillatory rotative direction of travel, a cam lug carried by one of said clutch elements, a series of links and levers with one end of alever connected to the hold-back foot and the end of another lever being in the path of said cam lug for operation thereby to raise the hold-back foot and means for varying the eifective operative movement of said series of links and levers to vary the height of raising movement of the material hold-back foot.

10. In an automatic material hold-back foot attachment for sewing machines, wherein the sewing machine includes a presser foot, a material feeding dog and operating means for the dog, said attachment including a tensioned holdback' foot postjacent the presser foot and normally lying in the operative plane of the presser foot to hold back and prevent stretching of the sewed material passed rearwardly of the presser foot and devices interposed between the tensioned hold-back foot and said operating means and operated by the latter to effect raising of the hold-back foot at predetermined intervals to release the sewed material held back by said tensioned hold-back foot, and means for varying the intervals at which the hold-back foot is raised for the release of the sewed material including a slotted arm having one end fixed to said operating means and a pin radially adjustably secured to an oscillatory element of said devices and ex tending into the slot of said arm.

11. An automatic material hold-back foot attachment for sewing machines as set forth in claim 2, wherein a vertically shiftable rod carries the hold-back foot and said devices include a series of links and levers with one end of a lever engaged with the upper end of the rod and means for varying the intervals at which the hold-back foot is raised for the release of the sewed material including a slotted arm having one end fixed to said operating means and a pin radially adjustably secured to an oscillatory element of said devices and extending into the slot of said arm.

12. An automatic material hold-back foot attachment for sewing machines as set forth in claim 2, wherein a vertically shiftable rod carries the hold-back foot and said devices include a series of links and lever with one end of a lever engaged with the upper end of the rod, and an obstruction on said rod adapted to be engaged by said presser foot whereby the hold-back foot may be manually raised when the cam lever is operated for raising the presser foot and means for varying the intervals at which the hold-back foot is raised for the release of the sewed material including a slotted arm having one end fixed to said operating means and a pin radially adjustably secured to an oscillatory element of said devices and extending into the slot of said arm.

13. An automatic material hold-back foot attachment for sewing machines as set forth in claim 2, wherein a vertically shiftable rod carries the hold-back foot and said devices include a series of links and levers with one end of a lever engaged with the upper end of the rod and means'for holding the hold-back foot in elevated inoperative position, and means for varying the intervals at which the hold-back foot is raised for the release of the sewed material including a slotted arm having one end fixed to said operating means and a pin radially adjustably secured to an oscillatory element of said devices and extending into the slot of said arm.

14. An automatic material hold-back foot attachment for sewing machines as set forth in claim2, wherein a vertically shiftable rod carries the hold-back foot and said devices include a series of links and levers with one end of a lever engaged with the upper end of the rod,

and an obstruction on said rod adapted to be engaged by said presser foot whereby the holdback foot may be manually raised when the tachment for sewing machines as set forth in claim 2, wherein said devices include adjustable means to vary the height of raising movement of the material hold-back foot and means for varying the intervals at which the hold-back foot is raised for the release of the sewed material including a slotted arm having one end fixed to said operating means and a pin radially adjustably secured to an oscillatory element of said devices and extending into the slot of said arm.

16. An automatic material hold-back foot attachment for sewing machines as set forth in claim 2, wherein said devices include clutch elements operative in one oscillatory rotative direction of travel, a cam lug carried by one of said clutch elements, a series of links and levers with one end of a lever connected to the hold-back foot and the end of another lever being in the path of said cam lug for operation thereby to raise the hold-back foot, and means for varying the intervals at which the hold-back foot is raised for the release of the sewed material including a slotted arm having one end fixed to said operating means and a pin radially adjustably secured to an oscillatory element of said devices and extending into the slot of said arm.

17. An automatic material hold-back foot attachment for sewing machines as set forth in claim 2, wherein said devices include clutch elements operative in one oscillatory rotative direction of travel, a cam lug carrier by one of 7 said clutch elements, a series of links and levers cam lever is operated for raising the presser with one end of a lever connected to the holdback foot and the end of another lever being in the path of said cam lug for operation thereby to raise the hold-back foot, means for varying the efiective operative movement of said series of links and levers to vary the height of raising movement of the material hold-back foot, and means for varying the intervals at which the hold-back foot is raised for the release of the sewed material including a slotted arm having one end fixed to said operating means and a pin radially adjustably secured to an oscillatory element of said devices and extending into the slot of said arm.

18. In an automatic material hold-back foot attachment for sewing machines, wherein the sewing machine includes a needle carry bar, a

presser foot, a material feeding dog and operating means for the dog, said attachment including a tensioned foot postjacent the presser foot and normally lying in the operative plane of the presser foot to hold back and prevent stretching of the sewed material passed rearwardly of the presser foot and devices interposed between the tensioned foot and said operating means and operated by the latter to effect raising of the hold-back foot at predetermined inter-'" vals following a predetermined number of re ciprocatory movements of the bar carrying the needle to release the sewed material held back by said tensioned foot, said devices including manually operable means for raising the holdback foot independently of the presser foot.

MEYER UNGER.

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