US2244424A - Sewing machine - Google Patents

Description

June 3, 1941. A. R. MAHANY SEWING MACHINE Filed on. .10, 1939 INVENTOR ATT RNEYS Patented June 3, 1941 SEWING MA'CH'INE Arthur Roland Mahany, Dunkirk, N. Y., assignor to Van Raalte Company, New 'York, N. Y.

Application October 10, .1939, Serial No. 298,814

2 Claims.

This invention relates to sewing machines and particularly to sewing machines of the class adapted to produce automatically and continuously a set sequence of varied stitches to produce a recurring pattern of stitching.

In the prior art, numerous examples of machines of this general nature may be found. Most of the machines, however, are highly special in nature and consequently prohibitively expensive, particularly in View of the fact that in most instances such machines are capable of producing only one of a very limited number of special stitch patterns.

According to the teachings of my invention a machine is provided which produces a particular form of novel stitching and one which may readily be altered to vary the character of the stitching produced. My invention may be conveniently produced by altering and modifying a zig-zag sewing machine which is well known in the art and widely used. There is disclosed herein a novel combination of elements for controlling the stitch forming mechanism and the work feeding instrumentalities in a simple yet practical and certain manner.

The present invention further discloses a novel yet highly practical and extremely simple means for producing a cloth feeding cycle consisting of a series of irregularly occurring feeding movements, whereby the work is fed between certain stitches of a given cycle comprising a predetermined number of stitches but not between others, according to a predetermined recurring pattern.

Other advantages, both structural and functional, will appear from a study of the accompanying drawing and the ensuing specification.

In the drawing:

Fig. 1 is a longitudinal vertical cross sectional view of a preferred form of the machine of my invention;

Fig. 2 is a bottom plan View of the machine; and

Fig. 3 is a fragmentary cross sectional View looking from left to right as the machine appears in Figs. 1 and 2 and showing the feed controlling cam mechanism.

For convenience and simplicity of disclosure the principles of the present invention are illustrated as comprising a modification of a Singer sewing machine of a type which is Well known in the art and usually referred to as a Singer zigzag machine. All details of the actual sewing mechanism and the feed dog, presser foot, and the like, are the same as corresponding elements of the Singer No. 107W1 sewing machine, ex-

cepting insofar as variations from the usual construction of such machines are indicated herein.

In the drawing like characters of reference denote like parts and the numeral I0 designates a bedplate for the machine with a standard I I mounted thereon and provided with an arm bracket l2. The latter gives pivotal support as at 13 to a needle bar carrying frame M which supports and guides, for vertical sliding movement, a needle bar IS. A main or needle bar driving shaft I6 is journaled in the arm bracket l2 in the conventional manner and has driving connection with the needle bar through a crank IT. The main shaft is may be rotated in a conventional manner as by means of an electric motor, not shown, which engages the shaft it through a belt drive cooperating with a pulley !8 on the shaft IS.

The needle bar I5 is caused to make successive stitches in different lateral positions by means of the pivotal mounting of the needle bar carrying frame It and the engagement therewith of mechanism for producing oscillation of the frame M about its pivot and such mechanism will now be described. In the illustration particular gear ratios for producing particular variations in stitching are shown and described in detail but it is to be understood that such specific relationship of the elements of the illustrated embodiment are shown by way of example and that the principles disclosed herein are subject to such modification and variation as will occur to those skilled in the art to which the invention pertains without departing from the spirit or scope of the invention as defined in the appended claims.

A stub shaft 20 is journaled transversely in the arm bracket l2 and is driven from the main shaft It by means of a pair of helical gears 2| and 22. In the illustrated embodiment the gears 2| and 22 are in the ratio of 1 to 2 so that the stub shaft 20 rotates one revolution for each two revolutions of the main shaft [6. A bearing bracket 23 which may be secured to the bedplate ill has secured therein a shaft 24. The shaft 24 has rotatably disposed thereon a gear 25 which meshes with a pinion 26 on the stub shaft 20 and the ratio of the gear 25 and the pinion 26 is 3 to 1 so that the gear 25, in the illustrated embodiment, goes through one complete revolution for each six revolutions of the main shaft iii.

A cam 28 is also rotatably disposed upon the shaft 24 and is fixed for rotation with the gear 25. An arm 29 is pivotally secured to a lateral extension 30 of the bearing bracket 23 by means of a pivot shaft 3!, such arm having at its outer end a cam roller 32 for engagement with the periphery of the cam 28. The cam roller 32 is held in engagement with the cam 28 by means of a leaf spring 33 which is secured at one end to the extension and has its other end bearing resiliently against the cam roller arm 29.

A second arm 35 is secured to the pivot shaft 3| for oscillation therewith and oscillations of the pivot shaft 3|, under control of the cam 28, are translated to the needle bar carrying frame M by virtue of a link 36 which is pivotally connected at its opposite ends to the outer end of the arm 35 and the needle bar carrying frame 24 respectively. The major portion of the contour of the cam 23, in the exemplary embodiment, is circular, the only deviation therefrom being the depression 33.

Referring now to the bottom plan view, Fig. 2, the numeral 40 indicates a conventional feed rockshaft for which appropriate bearings are provided at the under side of the bedplate I0. The feed rockshaft is oscillated by virtue of a conventional connection with the main shaft [6, such connection comprising a link 4| having eccentric connection with the main shaft as at 42 and being connected at its other end to an arm 53 fixed to the feed rockshaft. In this way the feed rockshaft is given one cycle of oscillation for each revolution of the main shaft. Also conventional is the feed dog carrying bracket shown at M and this bracket is given horizontal reciprocations by oscillation of the feed rockshaft, such horizontal reciprocations being duplicated by a feed dog 45 which is carried by the bracket 44.

The conventional path of travel of the feed dog in machines of this class is rectangular, with the upper horizontal portion of the movement being the actual feeding stroke. In my present machine, while I employ the usual mechanism for moving the feed dog horizontally to and fro, I provide special means for producing the vertical increments of movement of the feed dog, so that the feed dog, while moving to and fro between each successive stitch, is only raised from its lower non-feeding position on selected to and fro movements, whereby feeding movements-are imparted to the cloth only between certain stitches and not between others.

To this end special feed dog lifting means are provided and such means will now be described. The numeral designates a conventional looptaker actuating shaft which is driven by means of a belt 5| which engages pulleys 52 and 53 on the main shaft 16 and on the loop-taker actuating shaft 50 respectively. The loop-taker actuating shaft 56 rotates, in a conventional manner and through the bevel gear drive 54, :a rotary loop-taker which, through cooperation with a needle carried by the needle bar l5, produces lock stitches. A feed dog lifting rockshaft is provided as at 58 and such shaft is preferably of tubular construction and disposed about the loop-taker actuating shaft 50 for free rotation with respect thereto.

An arm Bil is fixed to the feed dog lifting rockshaft 58 and its outer end is pivotally connected to the feed dog carrying bracket 44 in such manner that oscillation of the shaft 58 .produces vertical reciprocation of the feed dog. The oscillations of the rockshaft 58 are synchronized to occur in such relation with respect to horizontal feeding movements of the feed dog that the latter, when acted upon by both the horizontal reciprocating mechanism and the vertical lifting and lowering mechanism now being described, moves upwardly, then forwardly to feed the cloth, then downwardly, then rearwardly in a lowered inoperative position to the starting point. As has previously been indicated, the feed dog is not raised with each forward movement, so that the cloth is fed only between certain predetermined stitches in a selected cycle of stitch variation.

The means for oscillating the feed dog lifting rockshaft at certain irregular intervals throughout a cycle of stitch variation will now be described. A bracket is secured to the lower side of the bedplate l0 and has formed thereon a horizontal extension 66 which is spaced downwardly from the bedplate 10. The extension 66 may be reinforced by a stud or stay bolt 61 engaging between it and the bedplate ID. A bearing block 68 is secured to the extension 66 and has journaled therein a shaft 69 which has secured to one of its ends a cam 18 and to the other a gear TI The gear H is gear-connected to a driving pinion 12 secured to one end of the loop-taker shaft 50 through the medium of a pair of intermediate gears 13 and 14 which are fixed to each other and mounted for free rotation against the bracket 65 by means of a stub shaft 15. The ratio of the intermeshing gears 12 and 13 is 1 to 6 and the ratio of the intermeshing gears 14 and H is 1 to 2 so that the shaft 69 which carries the cam T0, in the illustrated embodiment, goes through one complete revolution for each twelve revolutions of the loop-taker shaft 50 and, since the loop-taker shaft makes two revolutions for each revolution of the main shaft 16, the cam shaft 69 makes one revolution for each six revolutions of the main shaft I6. From the foregoing it will be seen that in the present instance the cam shaft 69 and the cam carrying shaft 24 travel at the same speed and this will ordinarily be the case although one of these shafts might be arranged to travel at a speed which is a multiple of the speed of the other in some cases.

The contour of the cam 10 is shown in detail in Fig. 3 and it will be noted that, in the form there shown, the cam is generally circular with a series of protuberances or rises 18 and these rises are four in number and spaced sixty degrees from each other so that the first and last of the series of four rises are spaced one hundred eighty degrees apart, thus providing for a one hundred eighty degree dwell following the series of four rises.

A follower roller is provided for cooperation with the cam 10 and is supported at the outer end of an arm 8| which is fixed to the feed dog lifting rockshaft 58. The follower 80 is held in engagement with the periphery of the cam 10 by virtue of a coil spring 82 which may be anchored to the extension 66 and to the arm 8| in any convenient manner. As the cam 10 rotates, each rise 18 imparts to the rockshaft 58 an oscillation which results in the successive lifting and lowering of the feed dog. Such lifting and lowering movements are timed to occur during the to and fro movement of the feed dog so that feeding movement of the feed dog in a rectangular path in the conventional manner is effected.

From the foregoing it will appear that between four successive stitches the feed dog will operate in the conventional way, through cooperation between the oscillations of the feed rockshaft 40 and the feed dog lifting rockshaft 58. After four such feeding movements, however, the uninterrupted portion of the cam 10 is encountered and thereabove and having a laterally shiftable three successive stitches are effected between which the cloth is not fed, that is to say, two feeding movements which would normally take place are omitted, due to failure of the feed dog lifting rockshaft to oscillate at such points, the usual to and fro movements of the feed dog occurring as usual but with the feed dog in a lowered position.

The special control means for the zig-zag movements of the needle bar l and the special feed controlling mechanism are timed with respect to each other and in the present instance such timed cooperation results in the following special sequence of stitching, beginning'with the parts in their illustrated positions. As the needle descends, a cloth feeding movement takes place and the machine subsequently takes a stitch. During the interval between this stitch and the next, there is no cloth feeding but the depression 38 of the cam 28 is encountered by the follower 32 and the needle bar carrying frame M is consequently oscillated about its pivot l3 so that the next stitch is effected laterally of the first stitch.

Between the second and third stitches, the cloth is again not fed forwardly but the roller 32 rides out of the depression 38 of the cam 28 so that the third stitch is made at the same place on the cloth as the first stitch. Subsequent to this, four successive forward stitches are effected by reason of the fact that the four rises 18 of the cam are encountered by the follower 80, during which time there is no lateral movement of the needle bar 5. The fourth of these successive forward stitches corresponds to the first stitch described in this paragraph and the cycle of stitching then repeats consecutively and automatically.

It is to be understood that either or both of the cams 28 and 10 may be replaced by cams having other contours and that by so doing a wide variety of ,stitch sequences and combinations of lateral and forward stitches may be effected.

What is claimed is:

1. In a sewing machine, an automatic stitch producing mechanism comprising, in combination, a bed plate, stitching mechanism disposed needle, a drive shaft for producing vertical reciprocation of said needle, a bracket detachably secured to the upper surface of said bed plate and cam means carried thereby and having connection with said needle to oscillate the same laterally, gearing between said cam means and said drive shaft to actuate the former from the latter, a loop-taker shaft disposed beneath said bed plate and rotatable with said drive shaft, a feed dog and a rock shaft for oscillating said feed dog horizontally, a second rock shaft for intermittently moving said feed dog upwardly and downwardly to render the same effective and ineffective to feed the work in the machine, and a second bracket detachably secured to the under side of said bed plate and cam means carried thereby for controlling movements of said second rock shaft.

2. In a sewing machine, an automatic stitch producing mechanism comprising, in combination, a bed plate, stitching mechanism disposed thereabove and having a laterally shiftable needle, a drive shaft for producing vertical reciprocation of said needle, cam mechanism for controlling the lateral disposition of said needle and a driving connection between said cam mechanism and the driving means, lock stitch forming mechanism beneath said bed plate including a loop-taker actuating shaft driven from said drive shaft, a feed dog and means for reciprocating the same horizontally to and fro during each stitch-forming cycle, said means comprising a rock shaft, an eccentric on said drive shaft, an arm on said rock shaft, and a connecting rod associated with said eccentric and said arm, and means for lifting and lowering said feed dog at predetermined intervals throughout a cycle comprising a plurality of stitches, said last-mentioned means comprising a rock shaft engageable with said feed dog and having an arm fixed thereto, a cam engaging said arm for actuating said rock shaft, and gearing between said loop-taker shaft and said cam for effecting rotation of the latter upon rotation of the former.

ARTHUR ROLAND MAHANY.

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