US2152766A - Sewing mechanism - Google Patents

Description

April 4, 1939. w. H. LEWIN SEWING MECHANISM Filed Dec. 9, 1936 3 Sheets-Sheet l I NV E NTOR.

William yi'en r q oGeurin B Y flzo uc 1 MJ ATTORNEYS April 4, 1939. w. H. LEWIN SEWING MECHANISM Filed Dec. 9, 1936 3 Sheets-Sheet 3 INVENTOR. William Kenya .6:

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BY WZOCKJ' ATTORNEY 5 Patented Apr. 4, 1939 UNITED STATES PATENT OFFICE SEWING MECHANISM William H. Lcwin, New York, N. Y. Application December 9, 1936, Serial No. 114,914

6 Claims. 01. 112-205 My invention relates to a new and improved sewing mechanism.

One of the objects of my invention is to provide a new and improved sewing machine for making zig-zag stitches in which the needle and looper operate in afixed path and in invariable timing.

Another object of my invention is to provide an improved machine for this purpose, said machine having improved means for feeding the work in a generally forward direction, and for reciprocating the work laterally relative to the normal line of forward feed, resulting in the production of zigzag stitches. Y Another object of my invention is to provide a. simple attachment which can be manufactured at low cost and which can be easily applied to any sewing machine which produces straight stitches, so as to convert said machine into a zig-zag machine. In particular, and without limiting the invention, the attachment can be readily applied to the well-known sewing machine designated in the trade .as Singer 95-40 in order to convert said machine to a zig-zag sewing machine.

Another object of my invention is to provide a sewing machine for making either 'zig-zag or straight-away stitches, at will, which will have the same reliability and the same high speed of operation in making zig-zag stitches as the ordinary machine which makes a straight stitch only.

Another object of my invention is to provide an improved feed dog, and a novel combination of feed dog and needle plate, and to provide novel 'means for operating the samein unison.

35 While I show the invention as applied to a lock-stitch machine, I do not wish to be limited to any particular type of sewing machine.

Zig-zag sewing machines have been on the market for many years, in which the needle-bar, in

4 addition to being vertically reciprocated, was vibrated laterally from side to side, across the line of feed, asin the Singer 107 W type., This necessitated mounting the sewing-hook or looper in such manner that the plane in which it turned coincided with the plane of lateral vibration of the needle-bar, that is, said plane was perpendicular to the line of forward feed. In such an arrangement, a distinct loss of efiiciency and speed was unavoidable, and said lateral motion resulted in'noise, vibration, and the rapid wear of the lateral motion also made it impossible to secure a constant or uniform adjustment between the sewing-hook and the needle. These disadvantages 55 and other disadvantages which are familiar to needle-bar and its related mechanism, and this those skilled in the construction and repair of these machines, ultimately reduced the speed of operation to about 2200 stitches per minute.

However, the ordinary sewing machine in which the needle-bar is not reciprocated laterally, and

in which the sewing-hook-rotates in a plane exactlyparallel to the line of feed, is capable of producing reliable stitching at speeds of 4000 stitches per minute.

According to the invention herein disclosed, I have secured an eflicient and reliable zig-zag stitch at speeds up to 4000 per minute, using the essential parts of a standard sewing machine, and.

without laterally reciprocating the needle-bar or changing the essential sewing mechanism, which makes this high-speed of operation possible without undue noise, vibration, or rapid wear.

" My invention is shown in connection with the accompanying drawings and description.

Fig. 1 is a side elevation of the improved machine. V

Fig. 2 is a bottom plan view of Fig. '1.

Fig. 3 is a detail elevation, partly in section showing the needle plate and feed dog at'the lefthand extreme of their lateral-travel.

Fig. 4 is a view similar to Fig. 3, showing the needle 'plate and feed dog at the right-hand extreme of their lateral travel.

Fig. 5 is an end elevation, taken at the righthand side of Fig. 1. i

Fig, 6 is-a perspective view of a casting which can be connected to the underside of the bedplate of a standard machine, said casting having some of the operating parts of the device mounted therein. I

Fig. 7 isa sectional view, on the line of Fig. 1, showing certain details of the feed mechanism. 1 V

Fig, 8. is a detail sectional view, on the line 8-8 of Fig. '7, showing certain details of the feed mechanism. 1

" Fig. 9 is an end elevation, partially in section,

on the line 99 of Fig. 1, showing certain oi. the connecting means for reciprocating the needle plate laterally.

Fig. 10 is a top plan view on the line l0l0 oi Fig. 1, showing certain details of the needle plate,

feed dog, and cover plate.

Fig. 11 is a detail perspective view showing a part of the needle plate and the feed dog.

. Fig. 12 is a detail sectional view on line l2-l2 of Fig. 2. Fig. 13 is a perspective view of the needle plate and its slide-rod extension.

Fig. 14 is a perspective view of part of the feed mechanism in which the double-headed arrows X, and Y, and Z denote the various movements of the feed dog.

Fig. 15 is a detail sectional view of part of the needle plate, showing one of the depending studs and rollers which laterally reciprocate the feed dog.

The invention is illustrated as embodied in a sewing machine of standard type and having many standard parts. Since this machine is wellknown on the market as Singer 95-40, it is unnecessary to state the details of those parts thereof which remain unchanged in the invention.

Referring to Fig. 1, said machine has a hollow arm I, bolted to a bedplate 2, said arm I carrying a main shaft 3, which is provided with a. balance wheel 4. Main shaft 3 carries a bevel gear 5, meshing in a one-to-one ratio with a bevel gear 5a of the vertical jack shaft 6, which is provided near its lower end with a bevel gear I, meshing in a two-to-one ratio with the bevel gear Ia of the sewing-hook shaft 8. Shaft 6 is supported near its lower end by an auxiliary bearing 9, which forms part of the casting Ill, (illustrated separately in Fig. 6). That part of shaft 6 which protrudes through bearing 9, carries another bevel gear II, which meshes in a one-to-two ratio with a bevel gear I2, carried on a short horizontal jack shaft I3, suitably journaled in the bearings Ma. and 4b, (Fig. 2), which forms part of casting I0. Said casting I0 is bolted to the underside of the bedplate 2 by means of four bolts I5, which also serve to attach arm I to the upper side of bedplate 2. Shaft I3 also carries a cam l6, of suitable profile, which cooperates with the forked end I'Ia of 9. connecting-rod I1. Said connecting-rod I1 is pivotally connected to a' link I8, as shown in Fig. 2, by means of an adjustable cone-screw I9, and its lock nut I9a.

Said link I8 is pivotally connected to another link 20, by means of an adjustable cone-screw 2|, and its lock nut 2|a. Said link 2|) is rigidly fastened to a shaft 22, which can be turned a few degrees in either direction, in its bearing 23, by means of a crank arm 24, rigidly fastened to said shaft 22, in order to adjust said shaft 22 to vary the throw of the connecting rod H from zero to maximum, thereby determining the width of the zig-zag stitches. To enable the operator to make this adjustment conveniently, crank arm 24 is connected to a thumb-screw 25, by means of an extension arm 26, which is pivotally connected to arm 24 by means of a pivot-screw 21, having a lock-nut 27a. The shank of the thumbscrew 25 is threaded into the extension arm 26 through a suitable slot 28, cut inthe hollow arm I and said thumb-screw 25 can be tightened at any desired setting of shaft 22, so as to hold shaft 22 in any of its adjusted positions.

Fig, 1 shows rod I! in neutral position and it is shown in Figs. 3 and 4, in the position of maximum throw.

Referring to Figs. 1 and 2, connecting-rod I'I terminates at its left-hand end in a yoke I'Ib, which is pivotally connected by means of a tapered pin 29 to a perforated lug 30 (Fig. 13), which is rigidly fastened by means of two screws 30a, to the underside of slide-rod 3|, slidably mounted in a suitable guideway (Figs. 9 and 10) milled into the bedplate 2. Said guideway has edges 32.

Said rod 3| has inclined side-edges, and the edges 32 of the guideway are correspondingly inclined, A clearance hole 33 (Figs. 2 and 10) is also cut through the bedplate 2, through which the lug 30 protrudes so that said lug can be connected to the yoke I'Ib by means of said pin 29, whose tapered surface fits snugly in the tapered bore of the lug 30. Said pin 29 is adjustable to allow for wear, by means of its threaded extension 29a and its lock nut 29b (Fig. 12).

-The left-hand end of the slide-rod 3| carries the needle plate N, rigidly fastened thereto by two screws 34, (Fig. 13), so that the needle plate N necessarily partakes of the lateral to-and-fro motion imparted to the slide-rod 3| by means of the reciprocating motion of the connectingrod I'I.

Figs. 3 and 4 show the respective positions of the novel parts at the ends of the left-hand and right-hand lateral movements of the needle plate and feed bar. V

The needle plate N fits in the guideway 35 of the bedplate 2 (Fig. 10), and the assembly is covered by a thin cover plate 36, fastened to bedplate 2 by means of four screws 31, and having an aperture 38, to expose a. section of the needle plate N containing the elongated needle-hole 62, and to expose the rows of teeth F1 and F2 of the feed dog F. These teeth protrude through therespective slots N1 and N2 of the needle plate N, in order to contact with the under surface of the work, and to feed the work, in the upper position of said feed dog. The presser-foot P holds the work down and said presser foot is of suiiicient width to allow for the side-to-side movement of the feed dog F.

- Sufficient bearing surface is given the slide-rod 3| in its guideway, so that the needle plate N attached thereto has no appreciable shake, or lost motion, and the latter is therefore given sufficient clearance in the guideway 35, and beneath the cover plate 36, so as to avoid friction at these points.

A detachable section 36a of the cover plate 36 is riveted to the movable slide-plate 39 (Fig. 2) slidably mounted in the guideway 35, and yieldingly retained therein by the spring 46,

As shown in Fig. '7, the underside of needle plate N is provided with downwardly projecting studs 4|a and 4Ib, secured to the needle plate by means of screws 42a and 42b. Turnably mounted on these respective studs are rollers 43a and 43b, which register withv notches 44a and 44b, respectively, of the feed dog F. Said rollers are of sufficient depth to allow for the up-and-down movement of the feed dog F, said movement being indicated by the double-headed arrow X in Fig. 14. sufiicient length to allow for the back-and-forth movement of the feed dog F in the direction of ordinary feed of the material and reverse thereto, as indicated by the double-headed arrow Y. The direction of ordinary forward feed of the cloth is indicated by arrow W.

As shown in Fig. 14, the feed dog F is rigidly fastened to the feed-bar 45, which is integral with the sleeve 45a, which is turnably and slidably mounted on the shaft 46, which is fixed to the crank arms 41a and 41b, integral with the rock shaft 48. There is sufiicient clearance between the ends of the sleeve 45a and the adjacent crank arms 41a and 41b, to allow for the side-to-side movement of the feed-bar 45, which is indicated by the double-headed arrow Z. Said side-byside movement is imparted to said feed-bar by means of the rollers 43a and 43bof needle plate N cooperating respectively with the notches 44a and 44b of the feed dog F.

Conventional means are employed to secure Likewise the said notches are of pivotally connected to a rod 5|, which is suitably.

reciprocated from the main shaft 3. The amplitude of its rocking movement, which determines the length of the switch, is varied from zero to maximum by conventional means, and is controlled by the operator through the usual thumbscrew 52.

Likewise, the up-and-down movement of the feed dog F is conventionally secured by means of a crank arm 53, which carries a stud 54, ,on which roller is mounted. Said roller cooperates with the forked end 4517 of the feed-bar 45 (Fig. '7). Crank arm 53 is carried by rock shaft 56 (Fig. 2), which is rockably mounted at its ends on adjustable cone bearings 51a and 51b, and said shaft 56 is rocked by means of crank arm 58, piv otally connected to a rod 59 which is suitably reciprocated from the main shaft}. The roller 55 of the crank arm 53 is ,of suflicient length to allow for the side-to-side movement of the feedbar member 45b, said movement being indicated by double-headed arrow Z (Fig. 14).

The ordinary needle-bans!) moves needle 6|, through the needle-hole 62, and the needle cooperates with the sewing-hook S in the usual manner. The bobbin case, bobbin case base and positioning finger, all of which are conventional, are not shown.

Referring to Fig. 11, it will be noted that the serrations or teeth of the feed dog F are cut at an angle of about 45 degrees relative to the longitudinal axis A-A and arrow W, so that when feeding the work forwardly and also laterally to.

the left, for instance (referring to Fig. 11), the working edges of the row of teeth F1 will be presented to the work approximately at right angle to the resultant movement of the work; and when feeding the work forwardly and also laterally to the right, the working edges of the row of teeth F2 are likewise presented to the work at right angles to the resultant movement of the work.

The operation of the mechanism is as follows:-

The feed-dog F is raised vertically so rows of teeth move upwardly through their respective slots in the needle plate to engage the work against the yielding pressure of the presser foot. The feed dog now moves forwardly (away from the operator), and at the same time the needle plate is shifted laterally to the right, so as to shift the cloth and the feed dog in the same direction. This combination of the simultaneous forward and lateral movements of the feed dog produces a resultant feeding movement of the work along a line which is inclined to the right of the longitudinal axis AA, and at an angle which depends upon the relationship between the setting of the amplitude of the zig-zag stitch and the setting of the length of the straight-away stitch. At the completion of the forward movement of the feed dog, which coincides with the completion of its lateral movement, the feed dog is moved beneath the level 0f the top of the needle plate, thereby losing contact with the work. The work is held immovable by the pressure of the presser foot against the needle plate, which remains stationary while the feed dog is now returned in an idle stroke towards the operator in a line parallel to, and to the right of, axis A-A. At the conclusion of the return or idle stroke, the feed dog is again that the moved upwardly to engage the work as before. It is again moved forwardly, but during this stroke the simultaneous lateral motion of.the

needle plate and feed dog takes place to the left of line A--A, so that the work is given a resultant feeding movement along a line which is inclined to the left of the axis A-A, and at an angle equal to that of the line of the first resultant feeding movement. At the completion of this simultaneous forward and lateral movement of the feed dog, it is again lowered beneath the level of the top of the needle plate andit is returned idly toward the operator, but this time in a line parallel to and to the left of, axis A-A'. The same cycle of movements is repeated.

In thetype ofmachine specifically illustrated herein, the needle-bar has only the usual vertical reciprocating movement. However, the attachment may be applied to a machine in which the needle bar moves in any direction. For convenience, the direction in which the work would be fed, if the needle plate and feed dog did not have said lateral reciprocating movement, may be designated as the direction of straightaway forward feed. The sewing hook or looper is turned or rocked or otherwise moved in a fixed plane. This plane is preferably, but not necessarily, parallel to said direction of straight-away forward feed. Said plane may be adjusted relative to said direction, but said plane does not change after adjustment and during the opera tion of the machine. i

The cam l6 has dwell portions which operate t hold the needle plate in fixed position, at predetermined intervals, and while the needle is in the work. While the needle plate is thus held against lateral movement, the feed-dog is moved back in its idle stroke. Hence the lateral movement of the needle plate is intermittent.

While I have shown a feed-dog, it is to be understood that other types of feeding devices could be substituted, whenever a feed-dog having a four-motion movement relative to the needleplate, is specified in-any partthereof, including the claims.

The movement of the feed dog (excepting its lateral to-and-fro movement) may be designated as the usual four-motion movement of the feed dog. The movement of the feed dog while it is in its upper position may be designated as a feeding stroke, and the movement of the feed dog while it is in its lower position may be designated as Whenever I refer to a needle plate in the claims. it is to be understood that I wish to include any equivalent work-support. It will be noted that the needle plate is connected directly to the feed device, by means of the studs a and llb (including the rollers), and the notches a and b. This direct connection makes it' unnecessary to provide a plurality of cams or the like, for producing the lateral movement of the needle plate, and the lateral movement of'the feed dog. Likewise and as shown in Fig. 11, the teeth of the feed dog have longitudinal; axes, said axes being inclined to the longitudinal axis of the feed dog. 1

Likewise, I do not wish to be limited to a feed dog having two separated rows'of teeth, as I may use a feed dog having a single row of teeth, or having more than two rows.

Likewise, the invention can be applied to a machine having one or more needles, and it can be used with embroidery machines.

In the embodiment specifically illustrated, the needle-bar has a reciprocating movement in the direction of its longitudinal axis, and this movement, for convenience, is designated as a vertical reciprocating movement. However, it would not be-departing from the invention if the needlebar had a movement or movements in addition to said reciprocating movement, or if the needle- 'ment of the needle plate being at an angle to the direction of movement of the needle, a movable feed device, operating mechanism adapted and operative to actuate the needle to-and-fro and to move the needle plate to-and-fro and to impart a four-motion movement of the feed device relative to the needle plate, direct connecting means between said needle plate and said feed device so that the feed device is moved to-and-fro in unison with the to-and-fro movement of the needle plate, said operating mechanism being operative and timed to move the feed device forwardly in a feeding stroke and simultaneously to move the needle plate and the feed device laterally in one direction, then to move the feed device rearwardly in an idle stroke while the needle plate is held against substantial movement, then to move the feed device forwardly in a feeding stroke while the needle plate and the feed device are moved in a second direction which is opposite to the first-mentioned direction, and then to move the feed device rearwardly in an idle stroke while,

the needle plate is held against substantial movement.

2. A sewing machine having a needle mounted for to-and-fro movement in a direction which makes an angle'with a horizontal plane, a needle plate mounted for to-and-fro movement in a horizontal plane, a movable feed device, said feed device being movable forwardly and rearwardly and vertically up-and-down relative to the needle plate, means directly connecting said needle plate and said feed device for simultaneous to-and-fro movement, when the needle plate is moved toand-fro.

.3. A sewing machine having a needle bar mounted for vertical reciprocating movement, a needle plate mounted for reciprocating lateral movement in a horizontal plane, a feed dog hav'- ing teeth which are located to project through an open portion of 'the needle plate, said feed dog being movable forwardly and rearwardly and vertically up-and-down relative to the needle plate, means connecting said needle plate and J said feed dog for simultaneous lateral movement, said teeth of said feed dog having longitudinal axes which are inclined relative to the longitudinal axis of the feed dog. Y

4. A sewing machine having a needle bar actuated by a main shaft for vertical reciprocating movement, a needle plate mounted for lateral reciprocating movement in a horizontal plane, a feed dog having teeth which are located to project through an open part of said plate, said sewing machine having a bed plate, a bearing device connected to the underside of said bed plate, a first vertical shaft connected to said main shaft and having the lower end thereof supported in said bearing device, a second and horizontal shaft supported in said bearing device, intermeshing gears connecting said first shaft and said second shaft, a link driven from said second shaft and connected to the needle plate and reciprocating the needle plate intermittentlyand laterally, means adapted to regulate the amplitude of lateral movement of said needle plate, said feed dog having longitudinal notches, said needle plate having depending members which are located in said notches so that the feed dog is moved laterally in unison with the needle plate, and supplemental mechanism adapted to impart a four-motion movement to said feed dog relative to said needle plate.

5. In a sewing machine, the sub-combination of a needle plate mounted for lateral reciprocating movement in a horizontal plane, said needle plate having an open part, a feed dog mounted for four-motion movement and having teeth which are located to project through said open part during part of the four-motion movement of said feed dog, mechanism operative to impart said four-motion movement to the feed dog, said needle plate having depending lugs which are located in corresponding recesses of the feed dog, so that the feed dog is also moved in unison with said lateral reciprocating movement of the needle plate.

6. A sewing machine having a bed plate, a bearing device connected to the underside of said bed plate, said sewing machine having a main shaft, 2. first vertical jack-shaft, gears connecting said main shaft and said first vertical jack-shaft in a first ratio, the bottom end of said first jackshaft extending below said bed plate and being supported in said bearing device, a second jackshaft supported in said bearing device below the work plate, gears connecting said first jack-shaft to said second jack-shaft in a second ratio which is lower than the first ratio, a link driven from the second jack-shaft, a needle plate mounted for lateral reciprocating movement in a horizontal plane and connected to and driven intermittently in said movement by said link, a

hook mounted on a hook-shaft, the first jackshaft being connected by gears to the hook shaft in a third ratio which is higher than the first ratio, a needle mounted for vertical reciprocating movement, said hook being mounted for turning a predetermined plane, said needle plate having an open part, a feed dog mounted for fourmotion movement relative to the needle plate and having teeth located so that they project through said open part during part of the four-motion movement of said feed dog,mechanism adapted and operative to impart said four-motion movement to the feed dog, said needle plate having depending lugs which are located in longitudinal recesses of the feed dog so that said feed dog is moved laterally in unison with the lateral reciprocating movement of the needle plate, the operating mechanism for the needle plate and in a second direction which is opposite to the first-mentioned direction, and then to move the feed dog rearwardly in a lower idle stroke while the needle plate is held against substantial lateral movement, and mechanism for regulating the stroke of said link, said mechanism including an additional jack-shaft which is mounted below the bed plate in said bearing member,

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