US2681627A - Feeding mechanism for sewing machines - Google Patents

Description

June 22, 1954 A s E JR w 2,681,627

FEEDING MECHANISM FOR SEWING 2 Sheets-Sheet 1 Filed Nov. 21 1952 h R Q IN V EN TOR. (fli t/1w OJ: Welgy, gm

WITNESS AT TORNEY June 22, 1954 5 MELQY, JR 2,681,627

FEEDING MECHANISM FOR SEWING MACHINES Filed Nov. 21, 1952 2 Sheets-Sheet 2 ATTORNEY Patented June 22, 1954 FEEDING MECHANISM FOR SEWING MACHINES Arthur S. Meloy, Jr., Stratford, Conn, assignor to The Singer Manufacturing Company, Elizabeth, N. J., a corporation of New Jersey Application November 21, 1952, Serial No. 321,875

The present invention relates to sewing machines and has for a primary object to provide an improved feeding mechanism therefor.

More specifically it is an object of the present invention to provide a new and improved feeding mechanism for a sewing machine in which the feed-stroke may be readily reversed and which is sufiiciently rigid as to be useful for heavy work without undue distortion.

The present invention constitutes an improvement over the construction illustrated in the U. S. patent of Kaier, No. 2,172,559, September 12, 1939.

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 embodiments of the invention which is hereinafter 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 with the accompanying drawings in which:

Fig. 1 is a bottom plan view of a sewing machine embodying the present invention.

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

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

Fig. 4 is a fragmentary vertical section view taken transversely through the bracket-arm of the machine illustrated in Fig. 1.

Fig. 5 is a schematic diagram of the feedadvance mechanism of the machine illustrated in Fig. 1, the position of the parts for normal feed advance being illustrated in full line and for reverse feed being illustrated in dotted lines.

With reference to the drawings, the present invention is embodied in a machine having a bed I, the upper face of which comprises a Worksupporting surface. In the usual manner, a standard 2 rises from one end of the bed I. Although not illustrated, it will be understood that the machine further includes a conventional bracket-arm which terminates in a head overhanging the bed at the point of stitch formation which members carry the usual sewing machine elements such as a needle-bar, presser-mechanism, take-up, thread tension, etc.

Journaled longitudinally of the bed I, as in suitable bearings in a depending boss 3 and in an enlarged boss 4 integral with one wall of a lubricant chamber 5, is a bed-shaft 6. The lubricant chamber 5 is completely enclosed and includes a bottom cover-plate 1 held in position as 3 Claims. (Cl. 112-210) by screws 8. A second boss 9, depending from the bed I and integral with that wall of the lubricant chamber 5 opposite from the boss 4, is provided. with a longitudinal bore that receives a hook-shaft sub-assembly including a hook-shaft l9 and a rotary hook H. It will be understood that within the lubricant chamber 5 the bedshaft 6 is geared to the hook-shaft It] in such a manner that the hook-shaft I!) will be driven at twice the speed of the bed-shaft 6, and that the hook-shaft sub-assembly includes means for conducting the required lubricant from the lubricant chamber 5 to the hook-raceway. Since the above structure forms no part of the present invention it has not been illustrated in detail. For a more complete disclosure of one specific construction which may be used at this portion of the machine, reference is made to the U. S. patent of Van Ness, No. 2,441,942, May 18, 1948.

The end of the bed-shaft 6 directly below the standard 2 carries a grooved belt-pulley 12 to which power is transmitted by means of a ribbed belt 3 for actuating the bed mechanisms of the machine. In the usual manner, power may be delivered to the belt 13 by a pulley located on an arm-shaft and which may be connected to a motor by means of a belt, all not shown.

The feeding mechanism of the present machine includes a feed-bar M which, in the customary manner, is adapted to carry a feed-dog l5, illustrated schematically in Fig. 5. Feed-lift movements are imparted to the feed-bar M by means of a feed-lift shaft l6 journaled in depending portions of the bed I parallel to the bed-shaft e by pintles ll. Oscillation is imparted to the feed-lift shaft I 6 by a depending crank 18 connected by a pi'tman [9 that includes a strap portion 28 embracing an eccentric 2| on the bed-shaft 6. The feed-lift shaft 66 carries a second crank 22 which is connected to the forked end 23 of the feed-bar M by a sliding block 24 carried on a lateral pin 25 fixed to the crank 22. By means of the above mechanism, it will be seen that, upon rotation of the bed-shaft 6, feed-lift movements will be transmitted to the feed-bar l4.

Adjustable and reversible feed-advance mov ments are imparted to the feed-bar I4 by a feedadvance shaft 26 also journaled in pintles ll secured in depending portions of the bed i and disposed parallel to the bed-shaft 6. The feedbar [4 is connected in a conventional manner to the shaft 28', i. e., by means of pintles 23 secured in the usual feed-rocker 29 integral with the shaft 2%. i 1

Adjustable and reversible oscillation is im- 3 parted to the feed-advance shaft 26 from the bed-shaft 6 by means including an adjustable eccentric 30 carried by the shaft 6. Although not herein described, the eccentric 38 may be similar to that disclosed in the U. S. patent of Myers, No. 2,128,031, August 23, 1938, wherein the throw of the eccentric portion therof may be readily varied. Surrounding the eccentric por tion of the eccentric 30 is a strap end-portion 3i 7 of a pitman 32 connected at its opposite end to a wrist-pin 33 which forms the joint of a toggle. Also connected to the wrist-pin 23 are two diverging toggle-links 3 3 and 35, the link 36 being connected at its opposite end to an anchorshaft 55, and the link 35 being connected. at its opposite end by means of a crank-pin 3'! to a crank 38 secured to the feed-advance shaft 26. From the above it will be seen that, as the bedshaft 8 is rotated, variable actuation is imparted to the pitman 32 by the adjustable eccentric 3t, which actuation, by means of the toggle corn prising links 34 and 35, is transmitted to the crank 38 and thus serves to impart variable and reversible oscillations to the feed-advance shaft 25.

The anchor-shaft 33 is carried at one end by an arm 39 integral with a stud G journaied in a boss integral with one of the end walls of the lubricant chamber 5. At its other end, the shaft 35 is carried by an arm ii fixed to a feedreversing shaft 42 journaled in spaced bosses 23 and 3 depending from the bed i. The shaft s2 and the stud 48 are journaled with their axes in line so that they may be oscillated in unison, and the shaft 42 and stud All, together with the arms 39 and All and anchor-shaft 35 form a yoke with the anchor-link freely pivoted to the eccentric portion thereof, or about the shaft 35.

To turn or adjust the feed-reversing shaft 52 there is provided a plate as fixed to the end of shaft 42 and having one end of a link it pivoted thereto eccentrically of the axis of shaft 32. The opposite end of link 45 is pivoted to a lever it intermediate the ends thereof. The lever it is pivoted at one end to the rear wall of the standard 2 of the machine by means of a transverse horizontal pivot pin All and the opposite end of the lever 46 projects through a vertical slot as in the front wall of the standard 2 to where it terminates in a hand-piece as. To maintain the parts in position such that the feed operates to advance the work through the machine, the plate 44 is biased in a counterclockwise direction seen in Fig. 4 by means of a tension spring 58 acting between a stud 5i fixed to the wall of the standard 2 and a stud 52 carried by the plate it eccentrically of the axis of the shaft $2. With this arrangement, it will be seen that, when the hand-piece 49 is depressed, the lever it is pivoted about the pin til which depresses the link 2-5 and thus serves to rotate the plate s -l against the action of spring 50 and, consequently, rotates the shaft '42 in a clockwise manner as seen in Fig. 4. Rotation of the shaft 42, as will he understood, shifts the shaft 36, which is carried eccentrically thereby on a parallel axis, from the full line position of Fig. 5 which represents the position of normal feed-advance to the dotted line position, which represents the position thereof for reverse feed. When the hand-piece 49 is released, the spring 5% will restore the parts to their normal position.

Particular reference is made to Fig. 5 which illustrates diagrammatically the relationship of the parts withthe sewing elements in one posi- 4 tion but with the feed-reversing shaft 42 in its two end positions, normal feed advance being illustrated in full-lines and reverse feed being illustrated in dotted lines. It will be seen that as the eccentric 3!] is rotated from the illustrated minimum position the pitman 32 will be progressively advanced until the maximum position is reached, which is from the illustrated position, and then will be retracted to the illustrated position. In the full line position of the parts, advancing the pitman 32 will tend to straighten the toggle and thus move the feeddogs E5 in the direction of the arrow A, which is the direction of normal feed-advance. However, in the dotted line position of the parts, advancing the pitman 32 from the illustrated position will tend to break the toggle and thus move the feed-dogs I 5 in the direction of the arrow B, which is the direction of reverse feed.

In operation, the operator may effect a momentary reversal of the feeding mechanism to perform back-tacking by depressing the handpiece 49, as by striking it with the hand. If any binding were present, such a manner of rapidly effecting stitch-reversal would be impossible. Also, if there were any binding, the spring 553 could not rapidly return the parts to normal position. In accordance with the present invention, the anchor-pin is supported in a yoke-like manner by the arms 39 and ii which substantially eliminates any tendency to bind, which thus permits a more rapid reversal of the feeding mechanism; a

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 inven tion, what I claim herein is: a

l. Feeding mechanism for a sewing machine having a bed, comprising a feed-advance shaft journaled in said bed, a crank projecting laterally from said shaft, a normally stationary 'anchor shaft, pivotally interconnected toggle-links connected at their opposite free ends to said crank and said anchor shaft, a rotary actuating shaft journaled in said bed, an eccentric carried by said actuating shaft, a pitman embracing said eccentric'at one end and connected with the pivotal interconnection of said toggle-links at the other end, whereby said pitman will act to straighten and break said toggle upon rotation of said eccen tric, rotatable supports journaled in said bed on aligned axes, said rotatable supports comprising a feed-reversing shaftand a stud located upon opposite sides of said toggle links, laterally extending arms fixed to said feed-reversing shaft and said stud, said anchor shaft being carried by said arms eccentrically of the axis of said supports, and means for rotating said supports.

2. Feeding mechanism for a sewing machine having a .bed, comprising a feed-advance shaft J'ournaled in said bed, a crank projecting laterally from said shaft, a normally stationary anchor shaft, pivotally interconnected toggle-links connected at their opposite free ends to said crank and said anchor shaft, a rotary actuating shaft iournaled in said bed, an eccentric carried by said actuating shaft, a pitman embracing said eccentric at one end and connected with the pivotal interconnection of said toggle-links at the other end, whereby said pitman will act to straighten and break said toggle upon rotation of said eccentric, rotatable supports journaled in said bed on aligned axes, said anchor shaft being carried by said supports eccentrically of the axes thereof, manually operable means for rotating said supports in one direction, and a spring means for restoring said supports to the normal position by rotation in the opposite direction.

3. Feeding mechanism for a sewing machine having a bed, comprising a feed-advance shaft journaled in said bed, a crank projecting laterally from said shaft, a, normally stationary anchor shaft, pivotally interconnected toggle-links connected at their opposite free ends to said crank and said anchor shaft, a rotary actuating shaft journaled in said bed, an eccentric carried by said actuating shaft, a pitman embracing said eccentrio at one end and connected with the pivotal interconnection of said toggle-links at the other end, whereby said pitman will act to straighten and break said toggle upon rotation of said eccentric, rotatable supports journaled in said bed on aligned axes, said anchor shaft being carried by said supports eccentrically of the axes thereof, and means for rotating said supports, said means comprising a feed-reversing shaft forming one of said supports, a plate secured to said feedreversing shaft, a manually operable link having one end secured to said plate for urging the same in one direction of rotation, and spring means secured to said plate for urging the same in the opposite direction of rotation for restoring said supports to a normal position.

References Cited in the file of this patent UNITED STATES PATENTS Number

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