US3853078A

US3853078A - Sewing machine with upper roller feeding device adjustable independently from the feed dog

Info

Publication number: US3853078A
Application number: US00343622A
Authority: US
Inventors: N Marforio
Original assignee: Virginio Rimoldi and Co SpA
Current assignee: Virginio Rimoldi and Co SpA
Priority date: 1972-04-11
Filing date: 1973-03-22
Publication date: 1974-12-10
Anticipated expiration: 1991-12-10
Also published as: DE2317975B2; DE2317975C3; JPS499351A; DE2317975A1; JPS5433185B2; IT951304B

Abstract

An upper work feeding device for sewing machines of the roller type independently adjustable relative to the conventional lower feeding device and elastically pressed in the direction of the needle plate to a position of operation within a bifurcated end portion of the machines presserfoot.

Description

United States Patent 1191 Marforio 1 1 Dec. 10, 1974 1 SEWING MACHINE WITH UPPER ROLLER 2,325,643 8/1943 Weis...; 112/214 FEEDING DEVICE ADJUSTABLE 2,544,549 3/1951 Beck et a1 112/214 2,730,977 1/1956 Hayes et a1. 112/214 INDEPENDENTLY FROM THE FEED DOG 2,887,077 5/1959 Hale 1 12/21 1 [75] Inventor: Nerino Marforio, Milan, Italy 3,141,428 7/1964 Reeber et a1. 1 1 12/21 1 3,163,139 12/1964 Hedegaard 112/211 x [73] Asslgneel -P vll'glmo Rlmoldl & Cw 3,485,193 12/1969 Landwehr et al 112/214 Italy [22] Filed: Mar. 22, 1973 Primary ExaminerWerner H. Schroeder [21] Appl. No.: 343,622

[30] Foreign Application Priority Data- Apr. 11, 1972 Italy 23000/72 [57] ABSTRACT [52] US. Cl. 112/211 An upper work feeding device for sewing machines of [51 Int. Cl D05b 27/00 the roller type independently adjustable relative to the [58] Field of Search 1l2/2,"l21.l3, 203, 205, conventional lower feeding device and elastically 1 12/210, 211, 212, 214 pressed in the direction of the needle plate to a position of operation within a bifurcated end portion of [56] References Cited the machines presserfoot.

UNITED STATES PATENTS 2,106,536 1/1938 Rubel et a1, 112/214 X 5 Claims, 6 Drawing Figures II Q99 C33 1: 7W4 39 i i 44 1 l I I =1 P 11 11 37 1 i 1! 1' t 3 4 40 f 49 3Q) A 1 \x\\\ l4 I1 I 1' 16 i I g 9 ,,11"I11111||H E T l@ m ::l

PAIENIEU DEC 1 01914 SEE! 1 N 4 PATENTEL BEE 1 01974 SHEET 30$ 4 PAIENIE 95s 1 01914 SHEET t Of 4 SEWING MACHINE WITH UPPER ROLLER FEEDING DEVICE ADJUSTABLE INDEPENDENTLY FROM THE FEED DOG BACKGROUND OF THE INVENTION The present invention relates to a sewing machine with an upper work feeding device that is adjustable independently of the feed dog which functions in a known manner and forms the lower work feeding device.

It is known that on sewing machines, in particular of the industrial type, the material that must be sewn, which is commonly called work,very frequently contains many layers of fabric lying one on top of the other. Thus when operating with materials of many layers, the overlapping layers of the workundergo a relative degree of slippage during the normal operating of the machine since the feed dog only comes into contact with the lower layer of the work, while the upper layer is held back by the pressure exerted by the presserfoot.

Since the various layers must advance by the same degree during the sewing operation, or slip by a certain amount when one of the layers is to be embroidered, it is usually necessary to use two feed devices one for the lower layer, in contact with the working surface, and the other for-the upper layer directly in contact with the presserfoot. The optional intermediate layers are thus pulled along practically without any slippage with respect to the end layers in contact with the respective feed devices. Devices are known for feeding the upper layer of the work consisting of gripping mechanisms in opposition to the lower feed dogs which periodically project from the working surface, activated in phase with these devices. In order to produce the intermittent advancement of the material with which they are in contact, these gripping mechanisms must have a complex movement comparable to an elliptical motion but fundamentally progressing in a quadrilateral pattern in order to permit the return course of the feed dog after releasing it from the material. Such devices known for feeding the upper layer have the disadvantage of requiring cumbersome supports and guides which must normally be applied to the resser-foot. Another disadvantage of the upper feed devices according to the known technique is based on the fact that the stitch is only adjusted by both feed devices or has to be regulated only when the machine is not running. For that reason, no controls were previously provided for adjusting the movement of the machine that were accessible from the outside, in view of the difficulty of inserting the known feed devices in the drive mechanisms.

Presented as the subject of the present invention, a sewing machine has now been devised having an upper feed device operating with rollers and adjustable independently from the lower feed dog. The sewing machine according to the present invention is character ized by the fact that it includes a combination of an upper feed device plus a feeding roller driven witha unidirectional intermittent movement by the main shaft of the machine and independently from the lower feed dog, means for transforming the rotating motion of said main shaft into angular, intermittent, and unidirectional movements of said feeding roller, and means for adjusting the breadth of the said angular movements;

the above-mentioned means include a first adjustable device capable of transforming the rotating movement into an alternating movement and a second device capable of making the said alternating movement intermittent and unidirectional; the first adjustable device also being capable of reducing the breadth of said unidirectional intermittent movement of the mentioned feeding roller from a maximum determined by the mentioned first device, while the machine is operating.

The upper feed device according to the present invention exerts pressure on the upper layer of material, confronting one or several rollers in the area of the working surface defined by the needle plate through suitable slits provided in the base of the presserfoot against which the feed dog acts, provided with one or several different notches. In this manner, placing the two feed devices in opposition is avoided and also, due to the fact that the upper device consists of one or more normally knurled rollers and not of the usual gripping mechanism, the guides which would otherwise be applied to the presserfoot are not necessary. It is only necessary to have a support weighing more than the journal proper. Thus the fact that there are two independent stitch-adjusting devices, one for the upper feed and one for the lower feed, offers the advantage of rapidly eliminating any possible creasing of the upper layer without influencing the arrangement of the lower layer, at least within rather wide limits. This is achieved while the machine is operating, with the advantage that the operator can directly control the result of the adjustment and intervene so as to obtain the desired result, proceeding as will be explained below, continuously reducing the length of the stitch as directed by a separate control designed to be activated when the machine is not running.

These and other objectives advantages, and characteristics of the sewing machine according to the invention will be obvious to specialists in the area; one exemplified embodiment is described below by way of an unlimited example, referring to the attached drawings, on which:

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 represents a front view in elevation of a sewing machine according to the present invention;

FIG. 2 represents a side view of the machine in FIG. 1, taken from the part indicated by arrow A;

FIG. 3 represents another side view of the machine in FIG. 1, taken from the side indicated by arrow B;

FIG. 4 represents a view in perspective, showing the stitch-adjusting mechanism of the upper feed device according to the present invention;

FIG. 5 represents a sectional view along line VV of FIG. 4; and

FIG. 6 represents a detailed plan view according to line VIVI in FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENT In reference to FIG. 1, a sewing machine is considered including a frame 10 generally made up of a base 11 having on the upper side a hollow support 12 provided with a head 13 capable of firmly supporting a needle bar 14, on which is mounted in a sliding manner a needle clamp 15 equipped with needle 16. Next to support 12, provision is made on base 11 for a working surface 17, over which the work slides as it is sewn by the machine.

Mounted inside base 11 in a rotating fashion there is a main shaft 18, equipped on the end projecting from the frame with a control wheel 19 provided with a drive pulley 20 capable of being connected to the usual means for driving the machine, which are not illustrated but represented in FIG. 1 by drive belt 21. The

rotating movements of pulley 20 are transmittedthrough main shaft 18 and kinematic mechanism to needle clamp 15, whichconsequently moves in an alternating fashion along needle bar 14. A presserfoot 22 presses the work, which in the specific case of the present invention is made up of many layers, against work ing surface 17. Corresponding to the said presserfoot 22, provision is made for a needle plate 23 '(FIG. 6) equipped with the usual slits 24 through which a gripping mechanism with a number of notches emerges which, together with the other known devices not illustrated constitutes the feed dog. Presserfoot 22 is provided with a base 26 of such dimensions as to cover the entire area of gripping mechanismf25, and capable of contending withthe various notches in this mechanism which project from the parallel slits 24 of needle plate 23, placed at appropriate distances from each other. Numeral 27 designates the external control which makes it possible, while the machine is running, to reduce the oscillations of the feed dog, which are preimposed by a device designed to be activated when the machine is not running with respect to which pushbutton 28 is visible. By means of devices well known in the technique, it isthus possible to reduce the extent to which gripping mechanism travels, i.e., the length traveled by the lower layer of material between two successive penetrations of needle 16 through the same work and needle hole 29 provided in needle plate 23.

In accordance with the present invention, an upper feed device is also provided containing at least one feed roller 30 capable of coming into contact with the upper layer of the work corresponding to the ample spaces 31 of needle plate 23 between the parallel slits 24 housing the notches of gripping mechanism 25, through suitable passage 32 formed by a bifurcated end portion in base 26 of the presserfoot 22. The material is pressed by feed roller 30 against the said needle plate in the same way in which gripping mechanism 10 presses against the lower surface of the base of the foot. In this way, the end layers of the work are transported by the feed device proper. The upper feed device is driven by main shaft 18, which transmits its rotating movements to a drive shaft 33 through a pair of pulleys 34 and 35 and serrated drive belt 36 (FIGS. 1 and 4). The movement of shaft 33 is transmitted to feed roller 30 (or to the se-' ries of coaxial rollers) through a kinematic chain whose end section is mounted and enclosed in several arms (FIGS. 1 and 3). One of these arms is vertical arm 37, on which the same roller (or a number of rollers) pivots, at least one is longitudinal and fundamentally horizontal, designated by 38, and there is also a transverse arm 39. The section of the kinematic chain between the above-mentioned arms contains a first serrated pulley 40 on which a serrated drive belt 41 is inserted, placed within the range of transverse arm 39 and connected to a second serrated pulley 42.

The latter pulley is tightly connected to a shaft 43 mounted in a rotating fashion in horizontal arm 38 and capable of transmitting the motion to a third serrated pulley 44 aligned with feed roller 30 and presserfoot 22.

Serrated pulley 44 is connected to a fourth pulley of the same type 45 by means of a serrated drive belt 46. Said fourth pulley is integral with feed roller 30 so that the motion imparted to the first pulley 40, by an output shaft 47 to which this pulley is tightly fitted, is transmitted to said roller.

The group of

arms

37, 38 and 39 constitute a single support which pivots freely on output shaft 47 which, in turn, has its free end inserted in a holding clamp 48 integral with a support 49 attached in a known manner to base 11 of frame 10.

In order to keep feed roller 30 elastically pressed in the direction of the needle plate 23, a helical spring 50 is provided, which is anchored by one of its ends to a dowel 51 attached to transverse arm 39 (FIG. 3) and by its other end to an eye 52 of a threaded bar 53, which is inserted freely in a boss 54 and is provided with a knurled nut 55 supplied in order to adjust the tension of spring 50. The disposition of spring 50 with respect to output shaft 47, on which the said group of arms pivots, permits feed roller 30 to be drawn elastically downward when said spring is found below-shaft 47 and, on the other hand, makes it possible to keep said roller at a distance from the working surface when the spring is located above said shaft. The latter condition is achieved when the group of arms are made to oscillate around their own fulcrum through lever 56, (FIG. 3) which is drawn downward by rod 57 connected to lever 58 of the usual presserbar lifting device 59.

Said device includes among other items a pivot 60 integral with lever 58 and provided with a support 61 on which the knwon lever 62 bearing presserfoot 22 is hinged. Between feed roller 30 and main shaft 18, means are provided which aresuitable for transforming the continuous rotating movement of the shaft into similar, intermittent, and unidirectional movements for said roller synchronized with gripping mechanism 25 of the feed dog, or which are suitable for adjusting the breadth of said angular movements.

These means are contained in an appropriate box 63 attached to support 49 and consist of a first adjustable device 64 capable of transforming a rotating movement into an alternating movement and a second transmission device 65 capable of turning said alternating movement into an angular, intermittent, and unidirectional movement (FIG. 4). Adjustable device 64 includes a stitch-lengthener with eccentric 66 (FIG. 5), of which a fires eccentric 67 is mounted loose on drive shaft 33 but prevented from sliding axially on this shaft, which has a peripheral groove 68 capable of accommodating a spring biased push button or elastic pin 69 projecting outside box 63. The above mentioned eccentric 67 has an eccentric hub 70 on which a second eccentric 71 is fastened, which is mounted so as to slide in a radial fashion over a grooved body 72 attached by means of screws 73 to drive shaft 33.

Outside the second eccentric 71 a rod 74 is mounted, whose other end is connected to a first link-rod 75 hinged on a pivot 76 of a second link-rod 77, whose function will be explained later on. Rod 74 and the first link-rod 75 are also connected through a link 78 to a drive arm 79 of the transmission device 65 consisting, for example, of a known (and therefore not detailed) unidirectional roller clutch connected to the alreadym'entioned'drive shaft 47. The second link-rod 77 is fitted tightly to a shaft 80 supportedby the said box 63 and provided with a lever 81-projecting outside the box. v By means of lever 81, it is possible to cause shaft 80 to rotate and thus move the position of pivot 76, on

which one end of the first link-rod 75 turns, thus varythe machine.

I claimz. 1 1. In a sewing machine having a main drive shaft, a work supporting surface having a needle plate, a needle carried in a needle clamp mounted for reciprocating movement and a bifurcated presserfoot with a feed dog operatively associated therewith for advancing a plurality of layers of work along the supporting surface to the or less, reduced with respect to the-value which would be involved upon each rotation of shaft 33 corresponding to a specific eccentricity of rod 74.

-While operating, corresponding to .the rotations of shaft 33 in this way are intermittent unidirectional rotations of output shaft 47 and thus of feed roller 30, having an amplitude which variesaccording to the positioning'of lever 81. The maximum value for the distance covered by these unidirectional movements is determined by the eccentricity of rod 74 with respect to shaft 33 an eccentricity which may be variedby-inserting elastic pin 69 in groove 68 of eccentric 67, causing the rotation'by a suitable angle of shaft 33 by manually activating control wheel 19. This typeof adjustment, which changes the transmission ratio beween drive shaft 33 and. clutch 65, must only be performed in a machine that is not running when a variation is necessary in the length of each stretch of upper material in relation to each stitch in order to exactly synchronize the upper and lower feed devices..-The length may be reduced by the fine adjustment achieved by activating lever 81 while the machineis running in order to rapidly eliminate possible creases present in the upper layer without influencing the disposition of the lower fabric atall and without interrupting the operation of the machine. in fact, if the upper layer should become ruffled in front of the needle, thusreducingthe width of the angular movements of the feed roller, the quantity of material fed at each stitch is diminished. in this way, it is also possible to produce a great deal of tension in the upper layer with respect to the lower when,

for example, a piece of elastic isapplied to any article of clothing whatsoever. Since the upper feed device at least provides for the fact that a roller is involved and not the usual gripping mechanisms, the portion in contact with the material seems to be very limited and therefore the action exerted on the upper layer should be more unstable than that characteristic of a gripping mechanism. Nevertheless, it must be kept in mind that the roller, unlike the gripping mechanism,.is always in contact with the material. Furthermore, the task of the roller is especially that of accompanying the upper layer of material, neutralizing the possible slippage between the different layers, while the true and proper action of feeding is carried out by the feed dog below.

Possible additions and/or changes may be made by specialists in the field in the exemplified embodiment of the sewing machine described above and illustrated according to the present invention,- without exceeding the scope of the invention. In particular, kinematic devices other than those described may be used, provided that' they have the same function of transmitting and 5 portion of the presserfoot.

transforming the motion from one point to another of needle for the formation of stitches therein, the improvement comprising: I V

a. an upper work feeding device including a feed roller mounted in the bifurcation of the presserfoot at a position located forwardly of the sewing machine needle and in direct line therewith for contact-with the upper layer of work in opposed relation to the feed dog; 7 h i b. drive means interconnecting the main drive shaft with said feed roller for effecting rotation of the latter;

1. said drive means including a first adjustable device for transfonning the motion of the main drive shaft into alternating movements, and f 2. a second transmission device operably con- .nected to said first adjustable device to receive the alternating movements therefrom and effect unidirectional and intermittent motion of said feed roller during itsalternating movement by said first adjustabledevice. j 2, The upper work feeding device according to claim 1 wherein said first adjustable device includes a drive shaft operatively connected to the main drive shaft, a rod (74) eccentrically mounted on the latter, a first link-rod (75) rotatably connected to said rod (74) and a drive arm (79) operatively connecting said first link rod (75) with said'second transmission device.

3'. The upper work feeding device according to claim for varying the ratio between the amplitudes of the oscillations by modifying the eccentricity of said rod (74) and said drive shaft (33).

4. The upper work feeding device according to claim 2 wherein said first adjustable device includes a second link-rod 77, a pivot upon which both said first and second link-rods are mounted, and a shaft 80 operatively connected to said second link-rod having a lever (81) fixed thereon for shifting the center of rotation of said first link-rod (75) and reduce the amplitude of each angular movement of said second transmission device corresponding to a given eccentricity of said rod (74) on said drive shaft (33).

5. The upper work feeding device according to claim 1 wherein said feed roller includes spring means for elastically pressing the latter in the direction of the needle plate for contact with the upper layer of work at a location with the passage formed by the bifurcated end

Claims

1. In a sewing machine having a main drive shaft, a work supporting surface having a needle plate, a needle carried in a needle clamp mounted for reciprocating movement and a bifurcated presserfoot with a feed dog operatively associated therewith for advancing a plurality of layers of work along the supporting surface to the needle for the formation of stitches therein, the improvement comprising: a. an upper work feeding device including a feed roller mounted in the bifurcation of the presserfoot at a position located forwardly of the sewing machine needle and in direct line therewith for contact with the upper layer of work in opposed relation to the feed dog; b. drive means interconnecting the main drive shaft with said feed roller for effecting rotation of the latter; 1. said drive means including a first adjustable device for transforming the motion of the main drive shaft into alternating movements, and 2. a second transmission device operably connected to said first adjustable device to receive the alternating movements therefrom and effect unidirectional and intermittent motion of said feed roller during its alternating movement by said first adjustable device.

2. a second transmission device operably connected to said first adjustable device to receive the alternating movements therefrom and effect unidirectional and intermittent motion of said feed roller during its alternating movement by said first adjustable device.

2. The upper work feeding device according to claim 1 wherein said first adjustable device includes a drive shaft operatively connected to the main drive shaft, a rod (74) eccentrically mounted on the latter, a first link-rod (75) rotatably connected to said rod (74) and a drive arm (79) operatively connecting said first link rod (75) with said second transmission device.

3. The upper work feeding device according to claim 2 wherein said first adjustable device includes a stitch lengthener with a first eccentric carried on said drive shaft having a rim with a groove (68), a spring biased push button (69) selectively movable into and from the groove (68), said first eccentric including an eccentric hub (70), a second eccentric (71) mounted on said first eccentric, a grooved body (72) fixed on said drive shaft, on which said second eccentric is slidable and said rod (74) being attached to said second eccentric for varying The ratio between the amplitudes of the oscillations by modifying the eccentricity of said rod (74) and said drive shaft (33).

4. The upper work feeding device according to claim 2 wherein said first adjustable device includes a second link-rod 77, a pivot upon which both said first and second link-rods are mounted, and a shaft 80 operatively connected to said second link-rod having a lever (81) fixed thereon for shifting the center of rotation of said first link-rod (75) and reduce the amplitude of each angular movement of said second transmission device (65) corresponding to a given eccentricity of said rod (74) on said drive shaft (33).

5. The upper work feeding device according to claim 1 wherein said feed roller includes spring means for elastically pressing the latter in the direction of the needle plate for contact with the upper layer of work at a location with the passage formed by the bifurcated end portion of the presserfoot.