US2974617A - Feeding mechanisms for sewing machines - Google Patents

Description

March 14, 1961 H. HACKLANDER FEEDING MECHANISMS FOR SEWING MACHINES Original Filed Sept. 14, 1956 2 Sheets$heet 1 INVENTOR. Hans Hack/under I I ATTORNEY Mai'ch- 14, 1961 H. HACKLANl DER 2,974,617

FEEDING MECHANISMS FOR SEWING MACHINES Original Filed Sept. 14, 1956 2 Sheets-Sheet 2 k zl -----|s -2o Fig. 4.

49' I 50 INVENTOR.

48 Hans Hack/under AT TOHNE Y Unite a Hans Hacklander, Warren Township, N.J., assignor to The Singer Manufacturing Company, Elizabeth, N.J., a corporation of New Jersey Original application Sept. 14,

Divided and this application 693,927

Claims. (Cl. 112-209) 1956, Ser. No. 609,836. Nov. 1, 1957, Ser. No.

The present invention relates to sewing machines and particularly to feeding mechanisms for sewing machines. It IS a primary object of this invention to provide an improved feeding mechanism that is adapted for high speed operation and particularly a differential feeding mechanism in which the over-all height of the parts is substantially reduced. It is also an object of this inventron to provide a new and improved means which is particularly useful in a differential feeding mechanism for facilitating adjustment of the feed dog height.

Having in mind the above and other objects that will be evident from an understanding of this disclosure, the invention comprises the devices, combinations and arrangements of parts as illustrated in the presently preferred embodiment of the invention which ishereinafter set forth in such detail as to enable those skilled in the art readily to understand the function, operation, construction and advantages of it when read in conjunction Y t with the accompanying drawings in which:

Fig. 1 is a fragmentary plan view of the bedof a sewing machine having a differential feeding mechanism embodying the present invention, with the cloth plate and other elements of the machine removed more clearly to illustrate the underlying mechanisms.

Fig. 2 is a sectional view taken substantially on the line 2-2 of Fig. 1.

Fig. 3'is a fragmentary detail sectional view taken substantially on the line 3--3 of Fig. 2.

Fig. 4 is a fragmentary rear elevational view, partly broken away and the cloth plate in section of the mecha-. nism'illustrated in Fig. 1.

Fig. 5 is a fragmentary detail sectional .view taken substantially on the line 5-5 of Fig. 1.

V The present invention is herein illustrated and described as embodied in the sewing machine forming the subject matter ofmy prior application, SerialNo. 609,836, filed September 14, 1956, from which this application has been divided. l a

1 There is illustrated in the drawings the bed 1 of the frame of a sewing machine, the bed including a bottom wall 2 and having a transverse wall .3 upstanding from the bottom wall 2, The 'wall 3 is spaced from the left end of the bed to provide a space at the left of the. wall as seen in Fig. 1 to accommodate the looper and feeding mechanisms of the machine. To the right of the wall 3, as seen in Fig. 1, there is a splash-lubricated compartment 4 that is closed by walls including a front wall 5 and a rear wall 6. ll p A rotary driven feed shaft 7 is journaled longitudinally of the bed 1 ina bearing bushing 8 in the wall 3 and in a bearing bushing 9 in boss 10 extending upwardly from the bottom wall2 adjacent to the free end thereof. The shaft 7 extends through the bushing 9 and on the cantilevered end thereof is mounted a conventional adjustable crank 11 including a crank head 12 secured upon the end ofthe shaft 7 and havinga diametrically arranged slot 13 in which is mounted for sliding movement a screw-controlled-slide block 14 carrying a crank pin 15. The strap atent O" 2,974,617 Patented Mar-.14, 1961 end 16 of a pitman 17 is mounted on the crank pin 15 and is held thereon by a nut 18 threaded onto the end of the pin. The other end of the pitman 17 carries a pivot pin 19 secured therein by a set screw 20. The pivot pin 19 is journaledin the spaced tines at the bifurcated end of a crank arm 21 having a split end clamped by screws 22 on the end of a feed advance rock shaft 23. The rock shaft 23 is arranged parallel to the feed shaft 7 and is journaled in a bearing bushing 24 in a boss 25 extending upwardlly from the bottom wall 2 of the bed and in a bearing bushing 26 in the wall 7.

A feed advance'rocker 27 (Fig. 2) is mounted upon the feedadvance rock shaft 23, the rock shaft 23 passing through a bore in the hub 28 of the rocker and secured therein by screws 29. The rocker 27 has a pair of upstanding crank arms 30 in which are journaled the ends of a pin 31 secured by a screw 32 in the strap end 33 of a horizontally disposed main feed her 34. A main feed ,dog 35 is mounted on the main feed bar 34 for lateral and for angular or tilting adjustments by means of a lateral stud 36 secured in the forward end of the feed bar 34 by a screw 37.

The main feed bar 34 has a pair of laterally extending lugs 38 in which is slidably mounted an auxiliary or differential feed bar 39 in the form of a rod that is arranged generally parallel to the main feed bar 34. Anauxiliary or differential feed dog 40 is mounted on the end of the differential feed bar 39 for lateral and for angular or tilting adjustments by means of a lateral stud 41 secured in .the end of the feed bar 39 by a screw 42. Mounted on the differential feed bar '39 between the lugs 38 is a collar 43 which is secured thereon in adjusted position by screws 44. Extending laterally from the collar 43 is an arm 45 having the free end 46 thereof slabbed and extending through'a slot 47 in a wear plate 48 secured to the main feed bar 34 by screws 49, which arm 45 holds the differential feed bar 39 against turning while providing for axial sliding relative to the main feed bar 34.

Also extending laterally from the collar 43 is a stud 50 upon which is pivotally mounted the strap end 51 of a drive link 52 secured thereon by a nut 53 screwed onto the end of the stud 50. The other end of the link 52 is bifurcated to provide tines 54 that embrace the opposite faces of a vertical lever arm 55 of a bell crank lever 56. The arm 55 has a substantially radial slot 57- in which rides a slide block 58, Fig. 3, that is pivotally mounted upon a headed pin 59 extending through the tines 54 of the 7 link 52 and secured therein by threads 60 formed upon the head end of the pin 59 and screwed into the adjacent one of the tines 54. The bell crank lever 56 has a hub 61 secured by a screw 62 to a pivot shaft 63 that is arranged parallel to the feed advance rock shaft 23 and journaled for oscillation in a bearing bushing 64 in the boss 25 and in a bearing bushing 65 in the wall 3. A second arm 66 on the bell crank lever 56 has secured thereto by a screw 67 a transverse pivot pin 68 upon the ends of which are pivotally mounted the tines of the bifuracted end of a connecting link 69. The opposite end of the connecting link 69 is also bifurcated and the tines thereof are pivotally mounted upon the ends of a pivot pin 70 secured by a screw 71 in the end of a crank arm 72 integral with and depending from the feed advance rocker 27.

Intermediate its ends, the link 52 is connected by means of a transverse pivot pin 73 to the bifurcated end of a control link 74, the opposite end of which is connected by a pivot pin '75 to an arm '76 of a control lever '77 pivoted intermediate its ends on the reduced end of a stud 78 secured by a screw 79 in the boss 25, Fig. 4. The lever 77 has a control arm 86 extending from the rear of the bed 1 which is adapted to be secured to an operator-actuated control means (not shown) such as a foot treadle.

In operation, feed advance motions are imparted to the main feed bar 34 by the crank arms 30 of the rocker 27, which is oscillated by the adjustable crank 11 through the pitman 17, crank 21 and feed advance rock shaft 23. Feed advance motions are imparted to the differential feed bar 39 by the crank arm 72 of the rocker 27 through the connecting link 69, bell crank lever 56 and link 52. Adjustment of the crank 11 will vary the oscillation imparted to the feed advance rock shaft 23 and the rocker 27 and thus simultaneously adjust the stroke of both the main feed and the differential feed. Adjustment of the differential feed relatively to the main feed is provided by the control lever 77 which, when actuated, will pivot the drive link 52 about the pivot pin 50 to move the slide block 58 on the end of the link along the slot 57 in the arm 55 of the bell crank lever toward and away from the pivot shaft 63, thus varying the stroke imparted to the differential feed bar 39. The mechanics of the differential feed drive connections are designed so that the stroke of the differential feed will be the same as that of the main feed when the end of the drive link 52 is substantially at the mid-point along the slot 57 in the lever arm 55, will be greater when further away from the pivot shaft 63 or beyond the mid-point, and will be less when closer to the pivot shaft 63. To minimize the actuation of the differential feed due to adjustment of the slide block 58 along the slot 57, the slot 57 is formed on an are about the axis of the pivot stud 50 when the elements are at the center of their cycle of motion.

The feed lift mechanism comprises an eccentric 81 mounted on the feed shaft 7 directly beneath the feed bar 34 and secured to the feed shaft 7 by a screw 82. Surrounding the eccentric 81 is a strap portion 83 of a block 84 having a grooved flat face 85 to which is adjustably secured an arm 86 by means of screws 87 extending through elongated slots 88 in the arm 86 and threaded into the block 84. A pivot pin 89 is secured in the end of the arm 86 by a screw 90, which pin 89 is journaled in lugs 91 integral with and depending from the main feed bar 34. The feed lift motion imparted to the main feed bar 34 is also transmitted to the differential feed bar 39 which is carried thereby. Vertical adjustment is provided by the adjustable arm 86 of the feed lift mechanism which, as will be apparent, will simultaneously effect an adjustment of both the main feed dog 35 and the auxiliary feed dog 40.

The present lower four-motion feeding mechanism operates in a conventional manner. Rotation of the feed shaft 36 will effect rotation of the feed lift eccentric and the feed advance crank 11. Rotation of the eccentric 81 will raise and lower the feed bars 34 and 39 while rotation of the crank 11 will impart advance and return movements to the feed bars. The feed bars are advanced while raised to effect feeding of the work and returned while lowered. Adjustment of the crank 11 will simultaneously adjust the stroke of both the main and differential feeds while adjustment of the slide block 58 along the slot 57 will effect adjustment of the stroke of the differential feed relative to that of the main feed.

Another desirable feature of a sewing machine feeding mechanism is that the feed dog should remain parallel to the work supporting surface during the feeding stroke. This end has been accomplished in the present construction by arranging the feed advance rock shaft 23 close to the top of the bed and designing the feed rocker arms 3 to be very short. Thus, upon oscillation of the arms 34 about the axis of the rock shaft 23, there is an appreciable vertical displacement of the end of the feed bar 34 which is designed to coincide with the actuation of the feed lift mechanism. As the feed lift mechanism raises the feed bar 34, the feed advance motion of the rocker 27 will not only advance the feed bar 34 but will also raise the end thereof connected to the rocker to offset the front to back tilting of the feed bar during the feeding stroke by the feed lift mechanism.

The separate pivot shaft 63 for the bell crank lever 56 has the advantage that the elevation of the parts can be substantially lowered while still maintaining adequate length for the lever arm 55 to provide the desired adjustment of the differential feed. With the lever arm 55 arranged vertically, the thickness of the bed 1 is determined by the necessary clearance for the lever arm 55. Having in mind the fact that for the purpose of maintaining the feed bar 34 parallel to the work supporting surface of the machine during the feeding strokes the feed advance rock shaft 23 Was arranged high to provide short rocker arms 30, mounting of the lever arm 55 on the rock shaft 23 would be prohibitive. In the present construction, .the lever arm 55 constitutes one arm of a bell crank lever 56 which is pivotally mounted on the separate pivot shaft 63 which is arranged vertically below the level of the feed advance shaft 23. Thus, the

lever arm 55 may be made the desired length without the necessity of increasing the thickness of the bed and without lowering the elevation of the feed advance rock shaft 23.

Numerous alterations of the structure herein disclosed will suggest themselves to those skilled in the art. However, it is to be understood that the present disclosure relates to a preferred embodiment of my invention which is for purposes of illustration only and not to be construed as a limitation of the invention. All such modifications which do not depart from the spirit of the invention are intended to be included within the scope of the appended claims.

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

1. Differential feeding mechanism for a sewing machine having a bed and a rotary feed shaft journaled in said bed, said mechanism comprising a feed advance rock shaft journaled in said bed parallel to said feed shaft, operative connections for imparting oscillation to said feed advance rock shaft upon rotation of said feed shaft, an upstanding crank arm secured to said feed advance rock shaft, a horizontally disposed main feed bar pivotally connected to the free end of said crank arm, operative connections for imparting feed lift motions to said main feed bar upon rotation of said feed shaft, a differential feed bar carried by said main feed bar for axial sliding motion in the direction of feed, a pivot shaft mounted in said bed parallel to said feed advance rock shaft and disposed below the level thereof, an upstanding lever arm extending from said pivot shaft, operative connections for imparting oscillation to said lever arm upon oscillation of said feed advance rock shaft, a drive link connected to said differential feed bar and to said lever arm for imparting feed advance motions to said differential feed bar upon oscillation of said lever arm, and means for adjusting the connection of said drive link to said lever arm radially of said pivot shaft to vary the feed advance motion imparted to said differential feed bar.

2. Differential feeding mechanism for a sewing machine having a bed and a rotary feed shaft journaled in said bed, said mechanism comprising a feed advance rock shaft journaled in said bed parallel to said feed shaft, operative connections for imparting oscillation to said feed advance rock shaft upon rotation of said feed shaft, an upstanding crank arm secured to said feed advance rock shaft, a horizontally disposed main feed bar pivotally connected to the free end of said crank arm, operative connections for imparting feed lift motions to said main feed bar upon rotation of said feed shaft, a differential feed bar carried by said main feed bar for axial sliding motion in the direction of feed, a pivot shaft mounted in said bed parallel to said feed advance rock shaft and disposed below the level thereof, an upstanding lever arm extending from said pivot shaft, operative connections for imparting oscillations to said lever arm upon oscillation of saidfeed advance rock shaft, a drive link pivotally connected to said differential feed bar and to said lever arm for adjustment along said lever arm radially relatively to the pivot axis thereof for imparting variable feed advance motions to said differential feed bar upon oscillation of said lever arm, an operatoractuated control lever pivotally mounted in said bed and having an arm and a control link connected to said arm and to said drive link for, adjusting the connection of said drive link along said lever arm. I

3. Differential feeding mechanism for a sewing machine having a bed, and a rotary feed shaft journaled in said bed, said mechanism comprising a feed advance rock shaft journaled in said bed parallel to said feed shaft, operative connections for imparting oscillation to said feed advance rock shaft upon rotation of said feed shaft, a rocker secured on said feed advance rock shaft and having an upstanding crank arm, a horizontally disposed main feed bar pivotally connected to the free end of said crank arm, operative connections for imparting feed lift motions to said feed bar upon rotation of said feed shaft, a differential feed barcarried by said main feed bar for axial sliding motion in the direction of feed,

a bell crank lever journaled in said bed for oscillation about an axis parallel to the axis of said weed advance rock shaft and below the level thereof, a second crank arm on said rocker, a connecting link operatively connecting said second crank arm to one lever arm of said bell crank lever for imparting oscillation to said bell crank lever upon oscillation of said rocker, a drive link connecting the second arm of said bell crank lever to said differential feed bar for imparting feed advance motions to said differential feed bar upon oscillation of said bell crank lever, and means for adjusting the connection of said drive link to the second arm of said bell crank lever radially relatively to the pivot axis of said bell crank lever to vary the feed advance motion imparted to said differential feed, bar.

4. Feeding mechanism for sewing machines having a bed and a rotary feed shaft journaled in said bed, said 1 feed dog upon the end of said feed bar for unitary movemechanism comprising a horizontally arranged feed bar overhanging said feed shaft and disposed at a right angle ment with said feed bar, operative connections between said feed shaft and said feed bar to impart feed advance motions to said feed bar upon rotation of said feed shaft, and n feed lift mechanism comprising an eccentric mounted upon said feed shaft below said feed bar, a block having a strap portion surrounding said eccentric and having a groove in the face thereof, said groove having opposed side walls. in a plane normal to the axis of said feed shaft, an arm seated in said groove and having a longitudinally elongated slot, threaded fastening means extending through said slot and threaded into said block for adjustably securing said arm to said block, and means for pivotally connecting the free end of said arm to said feed bar for imparting feed lift motions to said feed bar upon rotation of said feed shaft and for providing for adjustment of the height of said feed dog.

5. Feeding mechanism for sewing machines in accordance with claim 4 in which said means for mounting said feed dog upon thefree end of said feed bar includes means for providing for tilting adjustment of said feed.

dog about an axis transversely of said feed bar and laterally along said axis.

References Cited in the file of this patent UNITED STATES PATENTS 684,266 Klemm Oct. 8, 1901 993,452 Lohman May 30, 1911 1,260,772 Hemleb Mar. 26, 1918 1,663,490 Berger Mar. 20, 1928 1,884,489 Zeier et a1. Oct. 25, 1932 2,009,747 Sauer July 30, 1935 2,042,651 Clayton June 2, 1936 2,265,605 Kucera Dec. 9, 1941 2,324,861 Marsac July 20,1943 2,669,205 Hayes Feb. 16, 1954 2,720,853 Artzt Oct. 18, 1955 FOREIGN PATENTS 18,866

Great Britain Sept. 1, 1903

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