US2305556A - Feeding mechanism for sewing machines - Google Patents

Description

afP. PlNKvoss 2,305,556 FEEDING MECHANISMS FQR SEWING MACHINES De@ 1s, 1942.

Filed Nov. 2s, 1940 4 sheemsnqgr 1 Bertholc De. l5, 1942. I B p plNKVQsS FEEDING MEGHANISMS FOR SEWING MACHINES Filed Nov. 23, 1940 4 Sheets-Sheet. 2

Dec. 15, 1942.

B. P. PINKvoSs 2,305,556

v FEEDING MECHANISMS FOR SEWING MACHINES Filed Nov. 23, 1940 4 Sheecs--SheefI 3 Dec' 15,I 1942 B. P. PINKvoss FEEDING MECHANISMS FOR SEWING MACHINES.

' v Filod Nov. 23, 1940 y4 Sheets-Sheet 4 Patented Dec. Y15, 1942 FEEDING MECHANISM FOR` SEWING MACHINES Berthold P. Pinkvoss, Bridgeport, Conn., assignor to The Singer Manufacturing Company, Elizabeth, N. J., a corporation of New Jersey Application November 23, 1940, Serial No. 366,802

(Cl. 11B-210) 19 Claims.

This invention relates to feeding mechanisms for sewing machines and has for its. primary object to provide improved means .for controlling the effective action of a work-engaging feeding element, whereby the direction of feed may be reversed at will during the operation of the machine.

A furtherobject of the invention is to provide a compound needle and drop-feed mechanism with conveniently operable means for reversing the direction of feed. Other and more specific objects of the invention will be apparent from the following description and claims.,

The 4invention comprises the devices, combinations and arrangements of parts Vhereinafter described in connection with the accompanying drawings, which illustrate a sewing machine provided with a preferred embodiment of the improved feeding mechanism.

Fig. l is a longitudinal vertical section of a sewing .machine containing the'improved feeding mechanism. Fig. .2 is an enlarged vertical transverse section of the bracket-arm standard, substantially on the line 2--2 `of Fig. 1. Fig. 3 is a bottom plan View of the machine. Fig. 4 is an enlarged transverse vertical section vof the work-arm of the machine, Vthe section being taken Asubstantially on the line 4 4 of Fig. 1. Fig. 5 represents a horizontal section of the feed-dog carrier on substantially the line 5 5 of Fig. d. Fig. 6 represents a vertical section of the feed-dog carrier substantially on the line 3 5 of Fig. Li. Fig. 'i represents a disassembled perspective view of the feed-dog carrier. Fig.. 3 represents a detail view in top plan of Vthe feedreversing guide-rocker and slide-block, with the guide-rocker actuating pitznan shown partly in section. Figs. 9 and 10 are diagrammatical views of the feed-reversing actuating mechanism in reverse and forward feed positions thereof, respectively.

As shown in the drawings, the sewingmachine has a frame comprising a substantially rectangular base I9, from which horizontally extends an integral work-arm II provided at the 4free rotation of the actuating shaft 32.

end thereof with an end-closure plate II and Y with a generally cylindrical end-cap I2. Mounted upon the base It] is the hollow 'standard I3 of a tubular bracket-arm I4, which latter terminates at its free end in a head I5 overhanging At its opposite end, the shaft I6 carries a `arm `cessed in a side face thereof to Vreceive a length.-

for vertical reciprecation in a swinging frame 23. The frame 23 is pivotally supported at its upper end by a fulcrum-pin 24 secured in the bracketarm-head i5 by a set-screw 25. The fulcrumpin 24 is disposed so that pivotal-axis of the frame 23 is substantially Aparallel to the axis of rotation of the main-shaft I3, whereby the frame 23 is free to swing transversely of the length of the bracket-arm I4.

Complemental to the needle 22 in the formationof lock-switches is a loop-taker 2S of the vertical-axis rotary hook type and in which is journal-ed the usual thread-carrier 21 about which the loop-taker 2S casts needle-thread loops in the `formation of lock-stitches. The loop-taker 23 is carried by a `vertical shaft 23 rotatabiy journaled in a `bracket 29 supported at the free end Vof the work-arm II, the lower en'cl Vof said Yshaft carrying a bevel-pinion 33. In ldriving engagement with the pinion 33 is a bevelgear 3| carried by a horizontally disposed actuating shaft 32 journaled in a bearing-lug 33 of Ythe Work-arm II and in a lug 33' in the base I3, the ratio of the pinion 3i) and gear 3l being such thatA the loop-taker 26 rotates twice for each The shaft 32-is disposed in parallelism with the main shaft I6 and has a pulley `311. connected by a belt 35 with a pulley 36 carried by the main shaft Iii, the pulleys 34 and 36 being of the same size Awhereby the shafts I6 and 32 rotate one-to-one.

The work ,isA advanced by a reversible cornpound feeding mechanism including the needle 22 and a drop-feed feed-dog 3i provided with a needleaperture 38. The feed-dog 3l is disposed at'thefree end portion of the work-arm II and operates through suitable feed-slots provided in a throat-plate 39 at the upper side of the worn- II. The shank of the feed-dog 3l' is rewise vertically disposed supporting-rib til provided upon one side face of a feed-lift carrierblock 4I. The shank of the feed-dog 3T has a vertically elongated slot 42 through which passes a feed-dog Vsecuring screw 43 threaded into the carrier 4I, the described arrangement providing for vertical adjustment of the feed-dog. The feed-dog carrier-block 4i has a forwardly open fork 4,12 at the lower end thereof, said fork including a horizontally flattened lower face i6 of the carrier-block and an opposed attened face 45 of aV curved arm depending from said carrierblock. Engaged by the opposed faces of the carrier-block fork is a feed-lift eccentric 41 carried by the actuating shaft 32 at the free end of the work-arm II.

The feed-lift eccentric 41 has a flange 48 at one end v.thereof and separating the circumferential face of the eccentric 41 from a guide-sleeve 49 concentric with the shaft 32. The sleeve 48 is preferably integral with the eccentric-flange 43 and also with va collar 50 secured upon the shaft 32 by a screw 5I. The guide-sleeve 49 is slidingly engaged at the lower side thereof byv the horizontally flattened upper face 52 of the forwardly extending portion of an arm 53 depending from the rearward side of a vertically disposed feed-plate 54. The feed-plate 54 has a horizontally flattened lower face 55 opposed to the face 52 of the arm 53 and engaging the upper side of the guide-sleeve 49; it being understood that the described arrangement provides a forwardly open fork upon the feed-plate 54, which forlf` is slidingly mounted upon the guide-sleeve 49.

In the side face thereof proximate to the feedlift carrier block 4I, the feed-advance plate 54 has a recess 56 terminating at one side thereof in a vertical undercut guide-edge 51. Opposed 1':

to the guide-edge 51 is beveled edge 58 of a gib 69 secured by screws 60 to the feed-plate 54, thereby providing a vertical guideway upon the feed-plate. Confined to vertical sliding movement in said guideway are horizontally spaced 4S, which latter is free to rotate with the shaft 32 in the fork of said plate 54 and confines the guide-plate against bodily vertical movement. At the same time, the feed-lift eccentric 41 acts to raise and lower the carrier-block 4I upon and in timed relation to the movements of the feedplate 54 to complete the four-motion movements imparted to said feed-dog 31. As the carrierblock 4I is coni-ined against lateral movement relatively to the feed-plate 54, the fork 44 of said carrier-block slides rearwardly and forwardly upon the eccentric 41 with the feed-plate 54.

The flange 48 of the feed-lift eccentric serves to separate and guide the carrier-block 4I and feed-plate 54, the latter being conned by said flange 4S and the collar 5G against movement lengthwise of the shaft 32.

The feed-advance rock-shaft 65 is disposed in yfront of and substantially parallel to the actuating shaft 32, said rock-shaft extending lengthwise of and having one end journaled in the bearing-lug 33 of the work-arm. The other end of the rock-shaft 65 extends into the frame-base Ill, and another bearing for said rock-shaft is provided by a bushing 66 suitably secured in a lug 51 disposed at the juncture of the framebase IS and work-arm II.

Clamped upon the end of the rock-shaft 65 within the frame-base I is a crank-arm 68 connected by a pivot-bolt 69 to the lower end of a radius-bar 18 extending upwardly from the crank-arm 68 into the bracket-arm standard I3. The forked upper end of the radius-bar is pivotally provided with a slide-member 1I, said slide-member being slidably disposed upon a guideway which in the present case is in the form of a substantially straight guide-bar 12.

-The guide-bar 12 is secured at its opposite ends in parallel lugs 'L13Y extending from one side of a motion-reversing rocker 14; said lugs functioning as stops limiting sliding movement in oppo- `end of a link-member 96.

site directions of the slide-member 1I upon the guide-bar 12. Extending from the opposite side of the rocker 14 and substantially medianly of the length of the guide-bar 12 is a fulcrumshaft 15 for said rocker. The fulcruIn-shaft 15 is disposed substantially parallel to the main shaft I6 and is journaled in a bearing-bushing 16 secured by a screw 11 in a horizontal aperture provided in the bracket-arm standard I3.

The motion-reversing rocker 14 is connected, at one side of the fulcrum-axis thereof and by a pivot-bolt 18, to the lower end of a pitman 19, said pitman having at its upper end a strap embracing an eccentric carried by the main shaft I6. The eccentric 80 is preferably adjustable as to eccentricity, and the adjustment thereof may be eiected in any usual or suitable manner.

Clamped upon the feed-advance rock-shaft 65, adjacent the bearing-bushing 66, is another crank-arm 6I connected by a pivot-bolt 82 to the lower end of a link 83 extending upwardly into the bracket-arm standard I3. The upper end of the link 83 is pivotally connected to a crankarm 84 carried by one end of a needle-feed rockshaft 85. The needle-feed rock-shaft 85 is journaled in the bracket-arm I4 below and in parallelism with the main-shaft I6, and the other end of said rockshaft 85 carries a bent crank-arm 86 operatively connected to the needle-bar frame 23 for imparting swinging movements to said frame. The described connections between the needle-feed rock-shaft 85 and the feed-advance rock-shaft 55 are such as to impart unison workadvancing and return movements to the needle 22 and feed-dog 31; the needle-reciprocating and the needle-bar frame swinging movements being correspondingly timed so that the needle 22 is disposed in the feed-dog aperture 38 during the work-advancing movements of said needle and feed-dog. The feed-dog 31 is opposed by the usual spring-depressed presser-foot 81 which is suitably slotted to permit of work-feeding movements of the needle 22.

Extending lengthwise of and disposed slightly below the bracket-arm I4, in parallelism with the main shaft I6, is a feed-reversing shaft 8B; said shaft 88 having one end thereof journaled in a bracket 89 attached to the under side of the bracket-arm I4, and having its other end journaled in a suitable bearing-aperture provided in the arm-standard I3. Carried by the shaft 88, adjacent the bracket-arm head i5, is a depending hand-lever 90 having at its free end a laterally oifset linger-piece 9| disposed for convenient manual manipulation to rock the shaft 86.

The other end of the rock-shaft 88, within the arm-standard I3, has a forwardly extending and downwardly bent arm 92, provided withtwo ears 93 and 94 spaced lengthwise of the arm 92 and disposed at opposite sides of the radius-bar 1U which connects the feed-reversing rocker 14 to the feed rock-shaft 65. Pivotally connected to the ear S3 of the arm 92, by a screw 55, is one The opposite end of the link-member 66 is provided with a slot 91 elongated lengthwise of the link-member; and extending through the link-slot 31, in a direction lnormal to the length of the link-member 96, is

a connector-pin 98 secured by a set-screw 99 in a horizontally apertured boss |63 extending from one side of the radius-bar 16. Similarly, the other ear 94 of the arm 92 is pivotally connected by a screw IDI to one end of a link-member |62, opposed to the link-member 96. The link-member |02 has its other end disposed adjacent the nector-pin 98 is positioned in the adjacent linkmember slots 91, |03 to permit of limited lateral movement of the radius-bar 10 Without transmitting that movement to the hand-controlled rock-shaft 88 through the link-members 96, |02. In order Words, each of the link-members 96, |02 has a lost motion connection with the radiusbar 10.

It will be observed from Fig. 9 that, at one of the limits of movement of the motion-reversing rocker 14, the connector-pin 98 is disposed in the end portion of the link-member slot 91 remote from the pivotal connection 95 of said link-member 96 with the rock-shaft arm 02, and that said connector-pin 98 is disposed in the end portion of the link-member slot |03 proximate to the pivotal connection |I of the link-member |02 with the rock-shaft arm 92.

Upon rearward movement of the hand-lever 90 to shift the slide-member 1| from reverse to forward feed positions thereof, i. e., to shift the slide-member 1| to the right in Fig.V 9 of the drawings, the resulting movement of the rockshaft arm 92 initially has no effect to shift the radius-bar laterally, as the motion of said arm 92 is initially taken up by the link-member slots 91, |03. As soon as either one or both of the links 96 and |02 have been shifted sufciently to take up the lost motion aviforded by the slots 91, |03 thereof, the radius-bar 10 will be shiftedto the right until the slide-member 1| reaches its opposite limit of movement, illustrated in Fig. 10 of the drawings. It will be observed that the position of the connector-pin 98 in the link-member slots 01, |03 is now the reverse of that shown in Fig. 9. Consequently, the radius-bar 10 is again free to vibrate laterally, responsively to rocking movements of the motionreversing rocker 14, Without transmitting its movement to the hand-controlled rock-shaft 88.

In order yieldingly and automatically to maintain the slide-member 1| in either its forward or reversefeed positions upon the guide-bar 12, a bent link |04 has one end thereof pivotally connected by a screw |05 to the rock-shaft arm 92. The other end of the link |04 is connected by a coil-spring |06 to an anchor-post |01 comprising a screw adjustably threaded into the bracketarm standard I3. In the reverse and forward feed positions of the slide-member 1| uponthe guide-bar 12, illustrated diagrammatically in Figs. 9 and 10, respectively, a straight line representing the line of force of the spring |06 and connecting the pivot-screw |05 of the link |04 and the anchor-post |01 is disposed at opposite sides, respectively, of the rocking axis of the arm 92. Consequently, the pivotal `arm 92, the link |04 and the spring |09 together function as toggle-switch means urging the slide-member 1| yieldingly toward the stop-lugs 13 when the slidemember is shifted across the fulcrum-axis 15 of the rocker 14.

It will be observed from Fig. 9 of the drawings that, in the reverse feed position of the slidemember 1| upon the motion-reversing rocker 14,.

in a direction to urge the link |02 endw-ise to engage the connector-pin 98 of the radius-bar 10 from the right hand side of said radius-bar 10. In other words, the pivotal 15 of the rocker 14 and the pivotal axis lili of the link |02 are disposed at the saine side of the radiusbar 10. The effective length of the link |02 is substantially parallel to and of substantially the same length as the effective arm of .the rocker 14 comprising that portion of said rocker extending from the fulcrurn-axis 15 to the slide-member 1|. The parallel motion effect of the described arm of the rocker and the link it? reduces to a minimum and renders negligible from a practical standpoint any tendency to transmit the slight lateral motion of the radius-bar it) tothe handlever 90.

A similar condition prevails when ti e slidemember 1| is shifted across its fulcruin to the forward feeding position thereof iilustrated in Fig. 10 of the drawings, ine uch as the link 955 which under the action of the spring ist new assumes control of the radius-bar i is disposed at the opposite side of said radinsid from the link |02 and is substantially parallel and of a length substantially equal to ngth oi the effective arm of the rocker le. of the oppositely directed links for s.. slide-member 1| thus creates a condition peculiarly favorable to manual control of the feedreversing mechanism.

It will be understood from the l scription that changes in the amplitude o compound work-advancing movements of the feed-dog 31 and needle in eithe in reverse directions, are effected by t of the feed-actuating eccentric The direc tion of feed may be readily reversed hy manipulation of the conveniently located hand-lever Having thus set forth the nature of the tion what I claim herein is:

1. In a feeding mechanism for sewing machines having a work-engaging element, means for imparting operative Work-advancing move ments to said work-engaging element including a feed-reversing rocker provided with a guide- Way extending to opposite sides of the fulcrumaxis of said rocker, a slide-member shiftably disposed upon said guideway, and a manually operable rock-arm operatively connected to shift said slide-member upon said guideway to and from forward and reverse feed positions at opposite sides of the fulcrum-axis of said rocker, the improvement which consists in the provision of a spring connected to said rock-arm and having its lines of force disposed at opposite sides of the fulcrum-axis of said rock-arm in forward and reverse feed positions of said slide-member upon said feed-reversing rocker.

2. In a feeding mecra f chines having a Work-en g having an arm and fixed fuicr for actuating said rocker, a si` ably disposed upon said roc into an effective position uno s side of said fulcruni-axis of t; i bar operatively connecter to derive endvvise movement A" and connections for transmit' movements of said radius-bar to gaging element, the improvement i in the provision of a manually operable erin, and a link-member connecting said arm and said radius-bar and substantially equal in length to the effective length of the arm of said rocker, said link-member being disposed substantially parallel to and at the same side of said radiusbar as said arm of said rocker.

3. In a feeding mechanism for sewing machines having a work-engaging element, a roc having a fixed fulcrum-axis, means for actuating said rocker, a slide-member shiftably disposed upon said rocker for movement into forward and reverse feeding positions at opposite sides of said fulcrum-axis, a radius-bar operatively connected to said slide-member to derive endwise movement from said rocker, and connections for transmitting the endwise movements of said radius-bar to said work-engaging element, the improvement which consists in the provision of means for shifting said slide-member upon said rocker and including link-members operatively connecte-:i to and disposed at opposite sides of said radius-bar.

4. In a feeding mechanism for sewing machines having a work-engaging element, a rocker having a fixed fulcrum-axis, means for actuating said rocker, a slide-member shiftabiy disposed upon said rocker for movement into forward and reverse feeding positions at opposite sides of said fulcrum-axis, a radius-bar operatively connected to said slide-member to derive endwise movement from said rocker, and connections for trans-- mitting the endwise movements of said radiusbar to said work-engaging element, the improvement which consists in the provision of a rockarrn, and link-members pivotally connected to said rock-arm at opposite sides of said radiusbar, said link-members being operatively connected to said radius-bar to effect shifting of said slide-member in opposite directions upon said rocker by movement of said rock-arm.

5. In a feeding mechanism for sewing chines having a work-engaging element, a rocker having a fixed fulcrum-axis, means for actuating said rocker, a slide-member shiftably disposed upon said rocker for movement into forward and reverse feeding positions at opposite sides of said fulcrum-axis, a radius-bar operatively connected Lg,

to said slide-member to derive endwise movement from said rocker, and connections for transmitting the endwise movements of said radiusbar to said work-engaging element, the improvement which consists in the provision of a rockarm, link-members pivotally connected to said rock-arm at opposite sides of said radius-bar, the pivotal connections of said link-members with said rock-arm being radially equidistant with respect to the fulcrum-axis of said rock-arm, and

operative connections between said link-members and said radius-bar for shifting said slidemember in opposite directions upon said rocker by movement of said rock-arm.

6. In a feeding mechanism for sewing machines having a work-engaging element, a rocker having a xed fulcrum-axis, means for actuating said rocker, a slide-member shiftably disposed upon said rocker for movement into forward and reverse feeding positions at opposite sides of said fulcrum-axis, a radius-bar operatively connected to said slide-member to derive endwise movement from said rocker, and connections for transmitting the endwise movements oi said radius-bar to said work-engaging element, the improvement which consists in the provision of a rock-arm, and lost-motion connections between said radius-bar and said rock-arm extending in opposite directions from said radius-bar.

7. In a feeding mechanism for sewing machines having a work-engaging element, a rocker having a fixed fulcrum-axis, means for actuating said rocker, a slide-member shiftably disposed upon said rocker for movement into forward and reverse feeding positions at opposite sides of said fulcrum-axis, a radius-bar operatively connected to said slide-member to derive endwise movement from said rocker, and connections for transmitting the endwise movements of said radius-bar to said work-engaging element, the improvement which consists in the provision of a rock-arm, and link-members pivotally connected to said rock-arm at opposite sides of said radiusbar, said link-members each having a lost-motion connection with said radius-bar.

8. In a feeding mechanism for sewing machines having a work-engaging element, a rocker having a fixed fulcrum-axis, means for actuating said rocker, a slide-member shiftably disposed upon said rocker for movement into forward and reverse feeding positions at opposite sides of said f-ulcrum-axis, a radius-bar operatively connected to said slide-member to derive endwise movement from said rocker, and .connections for transinitting the endwise movements of said radiusoar to said work-engaging element, the improvement which consists in the provision of a rockarm, and links operatively connecting said rockarm to said radius-bar, the respective links having one of the ends thereof pivotally connected to said rock-arm at opposite sides of said radiusbar and having the opposite ends thereof pivotally connected to said radius-bar, one of the pivotal connections of each of said links comprising a lost-motion connection.

9. In a feeding mechanism for sewing machines having a work-engaging element, a rocker having a fixed fulcrum-axis, means for actuating said rocker, a slide-member shiftably disposed upon said rocker for movement into forward and reverse feeding positions at opposite sides of said fulcrum-axis, a radius-bar operatively connected to said slide-member to derive endwise movement from said rocker, and connections for transmitting the endwise movements of said radius-bar to said work-engaging element, the improvement which consists in the provision of a rock-arm, link-members pivotally connected to said rock-arm at opposite sides of said radiusbar, each of said link-members having a slot elongated lengthwise of the link-member, and a -connector-pin extending from said radius-bar through the slots of said links.

10. A feeding mechanism for sewing machines comprising, a work-engaging element, a rocker having a fixed fulcrum-axis, means for actuating said rocker, a slide-member shiftably disposed upon said rocker for movement into forward and reverse feeding positions at opposite sides of said fulcrum-axis, a radius-bar operatively connected to said slide-member to derive endwise movement from said rocker, operative connections for transmitting the endwise movements of said radius-bar to said Work-engaging elementJ a rock-shaft provided with a hand-lever, a. rock-arm carried by said rock-shaft, link-mem- .bers operatively connected to said radius-bar and pivotally connected to said rock-arm at opposite sides of said radius-bar, and yielding means urging said slide-member toward said forward and reverse feeding positions thereof upon said rocker.

BERTHOLD P. PINKVOSS.

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