US2782742A

US2782742A - Sewing machine

Info

Publication number: US2782742A
Application number: US295184A
Authority: US
Inventors: Hess Otto
Original assignee: Individual
Current assignee: Individual
Priority date: 1951-06-30
Filing date: 1952-06-24
Publication date: 1957-02-26
Anticipated expiration: 1974-02-26

Description

Feb. 26, 1957 Filed June 24, 1952 o. HESS SEWING MACHINE 5 Sheets-Sheet 1 Fig. 2

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Feb. 26, 1957 Filed June 24; 1952 o. HESS SEWING MACHINE Fig.5

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United States Patent The invention relates to a sewing machine, particularly a cloth or work feeding mechanism for a high-speed sewing machine. The feeding mechanism according to the invention may be applied to sewing machines with single feed dog as well as with differential feed dog, in which one or two feed bars are moved up and down by means of a lifting rocker and a cam, and, at the same time, oscillated horizontally by a feed rocker. The two feed bars ofa differential feed mechanism are arranged parallel to each other, and are operated jointly by the feed rocker.

It is an object of the present invention to design the cioth feeding mechanism of the above mentioned type of sewing machines in such a manner that the main driving shaft of thefsewing machine can rotate at higher speeds.

A further object of the invention is to adapt the feed mechanism in such a way that the portions of the feed bars which project out of the lifting rocker will become as short as possible and thus will form a short lever arm. This is an important feature for sewing heavy and thick fabrics, in order that the feed bars do not deflect under the high thrust created by the presser foot. Furthermore,'the oscillating speed of the lifting rocker can be lower when the projectioning lever arms are short.

Another object of the invention is to design the feed mechanism as simply as possible in order to avoid the driving mechanism of the feed dogs to be composed of too many moving parts, which might give rise to failures. With the type of sewing machines with differential feed dog in particular it is intended to eliminate the complicated means employed generally for transmitting the movement from the main driving shaft to the feed dogs of the sewing machine, which is essential for attaining a higher working speed of the sewing machine.

A still further object of the present invention as applied to sewing machines with differential feed mechanism, is

to reduce the length of the diflerential feed bar. 'As a result, the sewing machine can be operated at a greater number of revolutions than with machines, the differential feed dog of which is supported by a long bar-and operated by a complicated driving gear. 1

Finally it is an object of the present invention to provide aeloth feed mechanism composed of the least possible number of moving parts, whereby inertia forces are reduced. 1

According to the invention, a sewing machine with single cloth feed is provided with a main driving shaft, suitably supported in the machine and adapted to be rotated by the driving gear of the sewing machine, a feed dog adapted to transport the cloth and, for this purpose, to move along the path of an ellipse, the major axis of which is horizontal, a feed bar rigidly connected to said feed dog, a lifting rocker in which said feed bar is'mounted ata right angle with respect to said main driving shaft, said feed bar being adapted to shift in said lifting rocker and said feed dog being located directly beside said lifting rocker. Also according to the invention a cam is provided fixed to the main driving shaft 2,782,742 Patented Feb. 26, 1957 and rotatably mounted in said lifting rocker. A swinging head rockshaft is suitably supported in the sewing machine and parallel to said main driving shaft. A feed rocker is pivotally mounted upon said swinging head rockshaft, said feed bar being pivotally and directly connected to said feed rocker, and means are provided operable by said main driving shaft and adapted to transform said feed rocker into an oscillating swinging movement about the axis of said swinging head rockshaft.

In a sewing machine with differential feed mechanism according to the invention there are provided a main driving shaft suitably supported in the machine and adapted to be rotated by the driving gear of the sewing machine, a feed dog and a differential feed dog, both being adapted to advance the cloth to be sewed and each of which being adapted to move along the path of an ellipse, the major axis of which is located horizontally, a feed bar and a differential feed bar, being mounted parallel to each other and each of them being rigidly connected to the respective feed dog, a cam fixed to said main driving shaft, a lifting rocker in which said cam is rotatably mounted and in which said feed bar and said differential feed bar are shiftably mounted and adapted to execute a shifting motion at a right angle to said main driving shaft, said feed dog and said differential feed dog being located directly beside said lifting rocker, a swinging head rockshaft suitably supported by the sewing machine and located parallel to said main driving shaft, a feed rocker pivotally connected to said swinging head rockshaft, said feed bar being pivotally and directly connected to said feed rocker, means operated by said main driving shaft and adapted to transform said feed rocker into an oscillating swinging movement about the axis of said swinging head rockshaft, a cross slider shiftablymounted on said feed bar and located close beside said lifting rocker and being rigidly fixed to one end of said differential feed bar, and a lever pivotally connected at one end to said lifting rocker and at the other end to said cross slider and adapted to shift said cross slider to and fro along said feed bar.

Further details may be seen from the accompanying drawings which show, for purposes of illustrating the present invention, several embodiments in which the invention may take form, it being understood that the drawings are illustrative of the invention rather than limiting the same.

'In these drawings:

Fig. 1 is a side view, partly in section, of a single cloth feed mechanism,

Fig. 2 is a top view of the mechanism of Fig. 1,

Fig. 3 is a side view, partly in section, of a mechanism with differential feed dog mechanism,

- Fig. 4 is a top view, partly in section, of a mechanism according 'to Fig. 3,

Fig. 5 is a side view of a mechanism according to Figs. 3 and 4, shown in the direction of the arrow cm Fig. 3,

Figs. 6 to 9 are side views partly in section of four modified cross sliders for differential cloth feed mecha- 'nism, shown in'the direction of the arrow D in Fig. 4,

and partly sectioned along the line AB in Fig. 4,

Fig. 10 is a vertical sectional view of a portion of a feed bar taken along the line EF in Fig. 4.

The cloth feed mechanism with single feed dog according to Figs. 1 and 2 comprises a feed dog 1 of conventional design, which is attached to a feed bar 2 by means of a screw 34. The feed bar 2, for weight reducing purposes, is supplied with an inner bore 15 which is open at the end of the feed bar opposite to the feed dog 1. The feed bar 2 is shiftably mounted in a bore of a lifting rocker 3 which is adapted to move the feed bar 2 up and down, Furthermore, a feed rocker 4 imparts a horizontal oscillating motion to the feed bar 2, the resultant of both impulses being a motion of the feed dog 1 along the path of an ellipse.

A main driving shaft 6 suitably supported in the sewing machine carries a cam 7 whichris adjustable to take a specific angular position on the main driving shaft 6 and which is fixed thereon by a screw 35. The lifting rocker 3 is mounted on the cam 7, which moves the lifting rocker 3 up and down. The feed bar 2 is mounted at right angles to the main driving shaft 6.

In the sewing machine a swinging head rockshaft 8 is positioned parallel to the main driving shaft 6, and according to the embodiment presented in Figs. 1 and 2, is rigidly attached to the sewing machine. A hub 13 is rotatably mounted on the swinging head rockshaft 8 and is connected to the feed rocker 4, which may also be integral with the hub 13. The feed rocker 4 has a slot 36 of the kind represented and designated by 19 in Fig. 5. The slot 36 receives one end of the feed bar 2, which is pivotally connected to the feed rocker 4 by means of a bolt 20.

The aforementioned pivotal connection is represented in detail in Fig. 10. The articulated end of the hollow bushing 12 penetrates into the bore of the eye 47 of the connecting rod 10 and is fixed therein by a screw 48 fastened in the bushing 12.

When the main driving shaft 6 is rotated, the feed rocker 4, by means of cam 9, connecting rod 10, lever 11, and hub 13 executes an oscillating motion and transmits it to the feed bar 2.

As a matter of course, the arrangement may also be such that the hub 13 is eliminated; In this case the swinging head rockshaft 8 is rotatably supported in the sewing machine, and the feed rocker 4 and the lever 11 are fixed to the swinging head rockshaft 8.

The design of the feed dog 1 of a differential feeding I mechanism according to Figs. 3 to 5 is substantially the feed bar 2 is supplied with an eye 18, having a bore which partly penetrates into the bore 15 of the feed bar 2 and which is adapted to receive the bolt 20. A bushing 22 with an internal thread is inserted in the bore 15 of the feed bar 2 and is supplied with a curved tangential groove 23, the radius of curvature of which is greater than the radius of the bolt 20. Into the bushing 22 is screwed a head screw 21 whose head 37 bears against the face of the feed bar 2. When the screw 21 is fastened, the bushing 22 shifts in the bore 15 and the bolt 20 is clamped, the groove 23 thereby exerting a wedging efifect on the bolt 20.

The main driving shaft 6 is adapted to impart an oscillatory movement to the hub 13 by means of an intermediate mechanism comprising a cam 9, a connecting rod 10, and a lever 11, which is fixed to the hub 13. The main driving shaft 6 carries a set collar 38 which is slotted and is clamped to the main driving shaft 6 by means of screws 39. One face of the set collar 38 is provided with a dove-tailed groove 40 into which the dove-tailed foot 9' of the cam 9 is shiftably located. The cam 9 surrounds the main driving shaft 6 with suflicient clearance so that it may be adjusted eccentrically with respect to the main driving shaft 6. The foot 9' of the cam 9 can be connected to the set collar 38 in a determined position by means of a screw 41 which clamps together the slot of the set collar 38. For this purpose, the slot of the set collar 38 and the clamping screw 41 are arranged in such a way that the axis of the clamping screw 41 is situated at right angles to the adjustingdirectron of the foot 9 of the cam 9. Furthermore, in-a bore of the set collar 38 a bushing 42 is provided, having, parallel to its axis, a fiat portion which is in contact with the face of the foot 9 of the cam 9. A screw 43 is provided which penetrates through the bushing 42 and is screwed in the set collar 38, thus locating the bushing 42, whereby the flat portion of the bushing 42 is pressed against the face of the foot 9 of the cam 9, which is fixed thereby in its determined position. An arrangement of this kind is shown more clearly in Fig. 5.

The connecting rod 10 is supplied with a slotted eye 44, and is held together by a screw 45 and is articulated to the cam 9. The cam 9 has a spherical outer surface 9". The inner bore of the eye 44 is machined equally spherical, so that the eye 44 is articulated self-adjusting on the cam 9.

The lever 11 has a slotted end 46 which is clamped to the hub 13 by means of a screw 14. The opposite end of the lever 11 is also formed as a slotted eye 11 in which a bushing 12 is inserted which can be fixed in the eye 11' by pressing together the lips of the eye 11 by means of a screw 49. A corresponding embodiment of the last-named connection is represented in Fig. 5. The

same as that represented in Figs. 1 and 2. In addition, a differential feed dog 16 is provided which is secured to a differential feed bar 17. The latter is arranged parallel to the feed bar 2 and is shiftably supported in a second bore of an enlarged lifting rocker 300. The differential feed bar 17 is supplied with a bore 17' which is open to the end of the differential feed bar 17 carrying the differential feed dog 16. The opposite end 17" of the differential feed bar 17 is secured to a cross slider 24 shiftably mounted on the feed bar 2. The cross slider 24 carries a projecting trunnion 25, which bears the eye 50 of a lever 23. The opposite end of the lever 23' is formed as an eye 23" in which the feed rocker 400 is articulated.

Compared with the feed rocker 4 the feed rocker 400 is enlarged, and has a wing 26 with a slot 27 parallel to the plane through the axis of the swinging head rockshaft 8 and the axis of the bolt 20. A screw 28 with a head 28 is provided which can be adjusted and fixed in the slot 27 in a predetermined position. The screw 28 is screwed into a nut 29 having the form of a bushing with a flange 29'. A spacer 30 is inserted between the flange 29' and the wing 26, the eye 23" of the lever 23' being rotatably mounted on the spacer 30.

The differential feed bar 17 executes an oscillating movement proceeding from the cam 9 of the main driving shaft 6 and being transmitted to the feed bar 17 by the intermediate rocking linkage comprising the connecting rod 10, lever 11, hub 13, feed rocker 400, lever 23 and cross slider 24. The stroke of the aforementioned oscillating motion is adjustable by means of the screw 28 which can be shifted and fixed in a determined position in the slot 27 of the feed rocker 400. The slot 27 takes such a position, that the stroke of the differential feed dog 16 can be made equal to, or smaller or larger than that of the feed dog 1.

It is important that the feed bar 2 and the difierential feed bar 17 are guided exactly parallel to each other. In order to avoid any stress detrimental to the parallel motion of the two feed bars and possibly occasioned by the manner of fastening "the end 17" of the differential feed bar 17 to the cross slider 24, a special connection is provided for this purpose, which is represented in detail in the Figs. 6 to 9.

According to the structure set forth in Figs. 6 and 7, one end of the differential feed bar 17 is supplied with flat surfaces situated parallel to the connecting plane of the axis of the feed bar 2 and that of the differential feed bar 17. The cross slider 24 has a slot 31 extending in thedirection of the aforesaid connecting plane and into which the end 17" of the differential feed bar 17 penetrates. The width of the slot 31 corresponds to the distance of the aforementioned parallel surfaces of the differential feed bar 17. The two

lips

24 and 24" of the slotted portion of the cross slider 24 are connected together by one or more screws 32, to clamp the end 17" of the differential feed bar 17.

The screw 32 according to the embodiment of Fig. 7 is located outside the end 17". According to Fig. 6 it penetrates through a bore of the end 17".

The embodiment according to Fig. 8 provides a cross slider 24 with a here into which the end of the differential feed bar 17 penetrates. The end 170 of substantially circular cross section is supplied with a flat portion 51 against which presses a screw 33 fastened to the cross slider 24.

An embodiment according to Fig. 9 provides a differential feed bar 17 with an end 1700 of circular cross section which seats in a corresponding bore of cross slider 24. A slot 52 is supplied in the cross slider 24 extending up to the bore 1700. The

jaws

53 and 54 formed by the slot 52 are penetrated by one or more screws 55 adapted to clamp the end 1700.

What I claim is:

1. In a high speed sewing machine a cloth feeding mechanism comprising a main driving shaft supported in the machine and adapted to be rotated by a driving means of the sewing machine, a feed dog adapted to feed the cloth to be sewed and to move along the path of an ellipse the major axis of which is horizontal, a feed bar rigidly connected to said feed dog, a lifting rocker in which said feed bar is mounted and is adapted to shift in a direction at right angles to said main driving shaft, said feed dog being provided directly adjacent said lifting rocker, a cam fixed to said main driving shaft and rotatably mounted in and entirely surrounded by said lifting rocker, a swinging head rockshaft supported in the sewing machine parallel to said main driving shaft, a feed rocker pivotally mounted on said swinging head rockshaft, said feed bar being pivotally connected to said feed rocker, and means operated by said main driving shaft to place said feed rocker under an oscillating swinging motion around an axis of said swinging head rockshaft, said means including a cam mounted on and connected to the main driving shaft, a connecting rod of which one end is pivotally connected to said last-mentioned cam, a hub rotatably mounted on the stationary swinging head rockshaft and the feed rocker being secured thereto, and a lever secured to said hub with one end thereof pivotally connected to the other end of the connecting rod, the swinging head rockshaft being pivotally mounted in the sewing machine, and the feed rocker and the lever operating said feed rocker being secured to said swinging head rockshaft.

2. In a high speed sewing machine a cloth feeding mechanism comprising a main driving shaft supported in the machine and adapted to be rotated by a driving means of the sewing machine, a feed dog and a differential feed dog both adapted to feed the cloth to be worked and each of which is adapted to move along the path of an ellipse the major axis of which is horizontal, a feed bar and a differential feed bar mounted parallel to each other and each of which is rigidly connected to the respective feed dog, a cam fixed to said main driving shaft, a lifting rocker entirely surrounding the cam and in which said cam is pivotally mounted and in which said feed bar and said differential feed bar are shiftably mounted to execute a shifting motion, said feed dog and said differential feed dog being provided directly adjacent said lifting rocker, a swinging head rockshaft supported in the sewing machine and arranged parallel to said main driving shaft, a feed rocker pivotally mounted on said swinging head rockshaft, said feed bar being pivotally connected directly to said feed rocker, means operated by said main driving shaft to impart an oscillating swinging motion to said feed rocker around the axis of said swinging head rockshaft, a cross slider shiftably mounted on said feed bar adjacent said lifting rocker and rigidly fixed to one end of said differential feed bar, and a lever linked to said feed rocker at one end thereof and at the other end to said cross slider and adapted to shift said cross slider to and fro along said feed bar, a connecting rod one end of which is pivotally connected to said cam, a hub rotatably mounted upon the stationary swinging head rockshaft and to which the feed rocker is secured, and a lever secured to said hub one end of which is pivotally connected to the other end of the connecting rod.

3. In a high speed sewing machine a cloth feeding mechanism comprising a main driving shaft supported in the machine and adapted to be rotated by a driving means of thesewing machine, a feed dog and a differential feed dog both adapted to feed the cloth to be worked and each of which is adapted to move along the path of an ellipse the major axis of which is horizontal, a feed bar and a differential feed bar mounted parallel to each other and each of which is rigidly connected to the respective feed dog, a cam fixed to said main driving shaft, a lifting rocker entirely surrounding the cam and in which said cam is pivotally mounted and in which said feed bar and said differential feed bar are shiftably mounted to execute a shifting motion, said feed dog and said differential feed dog being provided directly adjacent said lifting rocker, a swinging head rockshaft supported in the sewing machine and arranged parallel to said main driving shaft, a feed rocker pivotally mounted on said swinging head rockshaft, said feed bar being pivotally connected directly to said feed rocker, means operated by said main driving shaft to impart an oscillating swinging motion to said feed rocker around the axis of said swinging head rockshaft, a cross slider shiftably mounted on said feed bar adjacent said lifting rocker and rigidly fixed to one end of said differential feed bar, and a lever linked to said feed rocker at one end thereof and at the other end to said cross slider and adapted to shift said cross slider to and fro along said feed bar, the feed rocker being provided with a wing member which is provided with a slot, a nut and a screw with a head, the screw penetrating said slot and being adjustable and fixable therein, the nut being shaped as a bushing with a flange, a spacer inserted between the flange and said wing, said lever being articulated relative to said cross slider and to said feed rocker, and the one end of said lever being shaped as an eye surrounding the spacer.

4. In a high speed sewing machine a cloth feeding mechanism comprising a main driving shaft supported in the machine and adapted to be rotated by a driving means of the sewing machine, a feed dog and a differential feed dog both adapted to feed the cloth to be worked and each of which is adapted to move along the path of an ellipse the major axis of which is horizontal, a feed bar and a differential feed bar mounted parallel to each other and each of which is rigidly connected to the respective feed dog, a cam fixed to said main driving shaft, a lifting rocker entirely surrounding the cam and in which said cam is pivotally mounted and in which said feed bar and said differential feed bar are shiftably mounted to execute a shifting motion, said feed dog and said differential feed dog being provided directly adjacent said lifting rocker, a swinging head rockshaft supported in the sewing machine and arranged parallel to said main driving shaft, a feed rocker pivotally mounted on said swinging head rockshaft, said feed bar being pivotally connected directly to said feed rocker, means operated by said main driving shaft to impart an oscillating swinging motion to said feed rocker around the axis of said swinging head-rockshaft, a cross slider shiftably mounted on said feed bar adjacent said lifting rocker and rigidly fixed to one end of said differential feed bar, and a lever linked to said feed rocker at one end thereof and at the other end to said cross slider and adapted to shift said cross slider to and fro along said feed bar, one end of the differential feed bar being provided with surfaces parallel to the connection plane of the axis of the feed bar and of the differential feed bar, the cross slider being provided with a slot at the point in which said cross slider is contacted by said differential feed bar, and said slot being located in the direction of said connecting plane and having a width corresponding to the distance of said parallel surfaces of said differential feed bar, the two lips of said cross slider formed by said slot being connected together by a screw to permit said screw and said lips to clamp the end of said difieren- 802,098 Free Oct. 17, 1905 tial feed bar. 1,109,635 Moffatt Sept. 1, 1914 1,148,446 De Voe July 27, 1915 References Cited in the file of this patent 2,102,202 Ebert Dec. 14, 1937 UNITED STATES, PATENTS 5 77 M nn A g- 1 1945 572,682 Merl-0w Dec. 8, 1896 2'546939 Breul 95 684,266 Klemm Oct. 8, 1901