US3673971A

US3673971A - Zigzag sewing machine

Info

Publication number: US3673971A
Application number: US68604A
Authority: US
Inventors: Takeshi Ono
Original assignee: Aisin Seiki Co Ltd
Current assignee: Aisin Corp
Priority date: 1969-09-04
Filing date: 1970-09-01
Publication date: 1972-07-04
Anticipated expiration: 1989-07-04
Also published as: DE2043399C3; GB1310830A; DE2043399B2; DE2043399A1

Abstract

A zigzag sewing machine equipped with a timing mechanism for the needle bar and hook to equalize the related positions both when the latter is to take the loop at any oscillated position of the needle, said timing mechanism comprising a crank rod connected to the rotatable gear and to the needle bar for imparting the vertical reciprocation to the needle bar in accordance with the lateral oscillation thereof.

Description

o Muted States Fateut [1s] 3,673,97 1 Ono July 4, 1972 [54] ZIGZAG SEWING MACHINE [56] References Cited [72] Inventor: Takeshi Ono, Kariya, Japan UNITED STATES PATENTS [73] Assignee: Aisin Seiki Kabushiki Kaisha, Kariya, 3,479,977 1 H1969 Meier. ..1 12/ 158 R Ja 1 3,247,817 4/1966 Eguchl ..1 12/158 R 3,507,236 4/1970 Komuro ..1 12/158 R [22] Filed: Sept. 1, 1970 21 L 8 604 Primary Examiner-Patrick D. Lawson AttorneyPierce, Scheffler & Parker [30] Foreign Application Priority D8118 57 ABSTRACT Sept. 4, 1969 Japan ..44/70l39 A zigzag Sewing machine equipped with a timing mechanism for the needle bar and hook to equalize the related positions both when the latter is to take the loop at any oscillated posi- 52 U.S. Cl. tion of the needle Said timing mechanism comprising a crank IL CL rod connected to the rotatable gear and to the needle bar for [58] Field of a B 158 C imparting the vertical reciprocation to the needle bar in ac- 1 i 58 cordance with the lateral oscillation thereof.

1 Claim, 5 Drawing Figures PKTENTEDJUL 4 I972 SHEET 2 0F 2 FIG. 3

/ ,IIIIII'IIIIIIIIII ZIGZAG SEWING MACHINE This invention relates to zigzag sewing machines, and more particularly to a novel and improved timing mechanism of a needle and a hook for the zigzag sewing machine.

The zigzag sewing machine has a shuttle mechanism including a hook to take a thread loop supplied from the needle. The hook is rotated or reciprocated in a fixed plane in spite of lateral oscillation of the needle. This is undesirable because the relative position of the needle and hook is changed in dependence upon the needle position. More specifically, it is common use for the hook to take the loop when the needle is positioned in the left position relative to the operator and raised up slightly from its lower dead center. Accordingly, the hook is compelled to be late to take the loop when the needle is positioned to the right, since the hook is required to rotationally advance from the corresponding left position to the corresponding right position.

Consequently, it is liable to produce objectable skip-stitch and thread-cut.

Therefore, the principal object of the present invention is to provide an improved zigzag sewing machine in which the height of the needle is controlled in dependence upon its laterally oscillated position whereby the relative position of the needle and hook is substantially the same at any oscillated position of the needle when the hook is to take the loop, so that the satisfactory zigzag sewing stitch can be obtained.

For an understanding of the principles of the invention, reference is made to the following description of a typical embodiment thereof as illustrated in the accompanying drawings.

In the drawings:

FIG. 1 is a front view partly in section of the zigzag sewing machine according to this invention, part of said machine being omitted;

FIG. 2 is a top plane view machine of FIG. 1;

FIG. 3 is a side elevation machine of FIG. 1;

FIG. 4 is a similar view.of FIG. 2,the constituent elements being represented in a schematic way; and

FIG. 5 is a schematic view for explaining the operation of the timing mechanism of the sewing machine,

With reference to FIGS. 1 to 3, there is illustrated a zigzag sewing machine having an arm head including a bracket arm 11. A horizontal main shaft 12 is longitudinally journaled in a bearing 13 in the bracket arm 11. A first bevel gear 14 is fixed to the end portion of the main shaft 12 by means of a setscrew 15 thereby being driven in unison with the main shaft 12. A support shaft 16 is securely mounted by a setscrew 17 on a protrusion 18 formed integrally with the bracket arm 11 and extends at right angles to the axis of the main shaft 12. There is provided a second bevel gear 19 which is rotatably mounted on the support shaft 16 and is provided with the same numbers of teeth thereon as the first bevel gear 14 to normally cooperate therewith.

The second bevel gear 19 comprises an integral pin' 20 which projects from its top face eccentrically from the rotating center 0 (FIG. 5) of the second bevel gear 19. One end of a crank rod 21 is pivoted on the integral pin 20 by a pin 22 while the other end thereof is pivoted on a needle bar holder 23 fixed to a needle bar 24 adapted to support a needle 25. Lateral vibration is imparted to the needle bar 24 by a rocking member 32 pivotally mounted on one end of a rocking rod 34. The other end of the rocking rod 34 is operatively connected to a zigzag width control box (not shown). The detailed operation of lateral oscillation of the needle 25 will be explained hereinafter with reference to FIG. 4, although the arrangement and operation form no part of the present invention.

A vertical shaft 26 is secured at each end to an upper boss 27 and a lower boss 28 and is arranged to be positioned in the horizontal line passing through the center C (FIG. 4) of the needle bar 24 as is seen in FIG. 2.

A shaftsupporting member 29 is pivotally mounted on the shaft 26 and has two

lugs

30 and 31 at the ends thereof. The rocking member 32 is disposed between the two lugs 30 and partly in section of the sewing partly in section of the sewing 31 of the supporting member 29 and is operatively connected thereto by a pin 37. The pin 37 is fixed to the two

lugs

30 and 31 at each end while pivotally mounting the rocking member 32 thereon. The rocking member 32 is provided with three lugs 34', 35 and 36 as shown the upper lug 34' and one of the lower lugs 35 being adapted to support the needle bar 24, and the other lower lug 36 having a slide block 38 pivoted thereto by a setscrew 41.

The slide block 38 is reciprocable in the perpendicular direction in FIG. 2 within a slot 39 of a hub portion 40 formed integrally with the bracket 1 l. The axial center of the slot 39 is arranged to be positioned in the same perpendicular line passing through the center A (FIG. 4) of the shaft 26 as is seen in FIG. 2. It should be noted that the needle bar 24 is prevented from rotating by the two lugs 34' and 35.

As is shown in FIG. 4, the oscillating mechanism including the shaft 26 (A), and pin 37 (B), the needle bar 24 (C), and the setscrew 41 (D) is arranged as follows:

where, A is the center of axis of the shaft 26, B is that of the pin 37, C is that of the needle bar 24, and D is that of the setscrew 41.

When the needle bar 24 is urged to move by the rocking rod 34, the oscillating mechanism operates in a manner of socalled Scottruosell movement, more particularly, the slide block 38 slides within the slot 39 in the vertical direction in FIG. 4 by the angular displacement of the support member 29. Consequently, the needle bar 24 is oscillated in the horizontal direction as indicated by the double-headed arrow so as to accomplish the zigzag stitch.

Referring to FIG. 5, 0 indicates the center of the second bevel gear 19, L and R indicate the left and right needle positions, respectively. E and F indicate each end of the crank rod 21 at the left needle position while E1 and F1 indicate the same at the right needle position. Locus of one end E or E1 may be represented by a circle. 0L and OR are the rotated ang'les of the second bevel gear 19 to position the needle 25 in the left position and in the right position, respectively. The angle OR is larger than the angle 6L by the angle 5 that is to say, the angular displacement of the second bevel gear 19 by 4: is required to shift the needle 25 to the right position from the left position. It should be noted that the angle 4) is nearly equal to the angle (#1 in which a hook in the shuttle mechanism is rotated from its left loop-taking position to its right loop-taking position, because the rotated angle of the second bevel gear 19 is equal to that of the first bevel gear 14 driven by the main shaft 12 and the main shaft 12 is operatively connected to the shuttle mechanism to cooperate therewith as will be apparent to those skilled in the art.

H indicates the height between the center 0 of the second bevel gear 19 and the other end F of the crank rod 21 in which the needle bar 24 is slightly raised up from the lower dead center so as to permit the hook 42 to take a thread loop (not shown).

The length and attachment of the crank rod 21 is arranged so that the height between the center 0 and the other end F1 is equal to the height II when the second bevel gear 19 is rotated by the angle 4:, and the hook 42 is rotated by the angle (1)].

Consequently, the relative positions of the needle bar 24 and the hook 42 are the same both in the left needle position L and in the right needle position R when the hook 42 takes the loop supplied from the needle 25, so that the satisfactory zigzag sewing stitch will be obtained.

What we claimed is 1. A zigzag sewing machine comprising a main shaft, a first bevel gear mounted thereon, a second bevel gear engaging said first bevel gear for rotation in a plane perpendicular to said first bevel gear, a needle bar, a needle supported by said needle bar, a crank rod connecting said needle bar to said second bevel gear for reciprocal motion in a vertical direction, means for laterally oscillating said needle bar, said means including an oscillating rod, and a rotating hook to take a thread 3 ,673 ,971 3 4 loop supplied by said needle, said second bevel gear being rotated in a direction opposite to the hook whereby the hook takes the thread loop supplied by said needle.

Claims

1. A zigzag sewing machine comprising a main shaft, a first bevel gear mounted thereon, a second bevel gear engaging said first bevel gear for rotation in a plane perpendicular to said first bevel gear, a needle bar, a needle supported by said needle bar, a crank rod connecting said needle bar to said second bevel gear for reciprocal motion in a vertical direction, means for laterally oscillating said needle bar, said means including an oscillating rod, and a rotating hook to take a thread loop supplied by said needle, said second bevel gear being rotated in a direction opposite to the hook whereby the hook takes the thread loop supplied by said needle.