US3064603A

US3064603A - Speed-changing cam device for zigzag sewing machines

Info

Publication number: US3064603A
Application number: US847791A
Authority: US
Inventors: Iida Hideo; Nario Masaji
Original assignee: FUJI SEIMITSU KOGYO KABUSHIKI
Current assignee: FUJI SEIMITSU KOGYO KABUSHIKI; FUJI SEIMITSU KOGYO KK
Priority date: 1959-10-21
Filing date: 1959-10-21
Publication date: 1962-11-20
Anticipated expiration: 1979-11-20

Description

1962 HIDEO IIDA EI'AL 3,064,603

SPEED-CHANGING CAM DEVICE FOR Z IGZAG SEWING MACHINES Filed 001.. 21, 1959 4 Sheets-Sheet l Nov. 20, 1962 HIDEO HDA EI'AL SPEED-CHANGING CAM DEVICE FOR ZIGZAG SEWING MACHINES 4 Sheets-Sheet 2 Filed Oct. 21, 1959 NOV. 20, 1962 HIDEQ "DA r 3,064,603

SPEED-CHANGING CAM DEVICE FOR ZIGZAG SEWING MACHINES Filed Oct. 21, 3.959 4 Sheets-Sheet 3 1962 HIDEO llDA EFAL 3,06

SPEED-CHANGING CAM DEVICE FOR ZIGZAG SEWING MACHINES Filed 001;. 21, 1959 4 Sheets-Sheet -4 rates This invention relates to a speed-changing cam device for zigzag sewing machines which automatically regulates, by means of a cam mechanism moving synchronously with the main shaft, the mechanism which regulates the fabric feeding motion or the side oscillation motion of the needle of a sewing machine.

It is an object of this invention to provide a device wherein, by an extremely simple operation, the rotational speed ratio between the automatic operation cam shaft and the main shaft can be changed steplessly and, moreover, quietly and positively.

In the conventional automatic zigzag sewing machines of the cam-changing type, it has been necessary to provide a large number of different cams as accessories, because only one kind of pattern could be obtained with one cam, this necessity being ineflicient and uneconomical in time and cost. In the present invention, however, by a simple manipulation of a pattern regulating lever installed on, and co-axially with, a zigzag amplitude control knob, sewing of numerous patterns of different spatial pitch can be carried out with the use of one cam, and various excellent results can be thus obtained, thereby enabling the attainment of the aforementioned object and other objects as will be apparent from the following disclosure.

The details of theinvention will be more clearly apparent by reference to the following detailed description of one representative embodiment of the invention when taken in connection with the accompanying drawings, in which:

FIG. 1 is a perspective view of the principal mechanism of an ordinary zigzag sewing machine, of general type, to which the device of the present invention is to be installed;

FIG. 2 is a plan View, partially in section and with parts cut away, of the mechanism of FIG. 1 to which the device of the present invention has been installed;

FIG. 3 and 4 are elevational views, in section with parts cut away, taken along planes IIIIII and IV-IV, respectively, of FIG. 2;

FIG. 5 is similarly an elevational view, in section, taken along the plane VV of FIG. 2;

FIGS. 6, 7, and 8 are plan views for explanation of the manual-automatic switching device to be used in the device of the present invention;

FIG. 9 is a perspective, exploded view illustrating the device of the present invention;

FIGS. 10 and 11 are graphical line diagrams showing the motions of the speed-changing mechanism of the device of the present invention.

Referring to the drawings, wherein the same or equivalent parts are designated respectively by the same reference numeral 1 designates the sewing machine arm 1 in which a main driving shaft 2 is supported rotatably on horizontal bearings. Rotation of said main shaft 2 is supported rotatably on horizontal bearings. Rotation of said main shaft 2 is transmitted though a balance weight 3, a crank pin 4 a crank rod 5, and a needle bar pin 6 to actuate a needle bar 7 in an up-and-down motion. At the same time, said rotation of the main shaft 2 is transmitted through a spiral gear 8 fixed 0n the main shaft 2 3,654,603 Patented Nov. 20, 1962 and another spiral gear 9, which is enmeshed perpendicularly with the gear 8, to rotate a triangular cam 10 which in turn causes a forked rod 11, engaged as a follower with said cam 10, to oscillate. This oscillation is transmitted through a pin 12 at the lower end of said forked arm 11 to oscillate a needle bar swinging frame 14, which under-goes a pendulum motion with a pin 13, fixed to the arm 1, as its fulcrum point. The resultant motion imparted to the needle bar 7 is a zigzag sewing motion.

The zigzag amplitude is controlled by manipulation of the zigzag control knob 15 on the front surface of the arm 1, the motions thereof being transmitted through a shaft 16, and arm 17, a roller 18, and a fork 19 to adjust the angle of the guide slot of a zigzag guide bracket 22, which guides the slide block 21 supported pivotally on a pin 21} on the forked rod 11.

On one hand, an automatic operation arm 26 is connected to an arm 23 of the zigzag guide bracket 22 through a pin 24 and a link 25, and automatic control of the zigzag amplitude is effected by an automatic operation cam 29 acting through a switching pawl 27 and a follower arm 28.

A boss 36) of the automatic operation arm 26 is fitted to rotate freely on a shaft 34, which is fixed by a nut 33 to a boss 32 of an automatic operation base plate 31. In addition, the follower arm 28 is pivoted on a shaft 34, and a roller 36 mounted on said follower arm 28 is forced by a spring 35 to press in close contact against the peripheral contour of the automatic operation cam 29. The switching pawl 27 is supported pivotally by a pin 37 to the arm 28. The free tip of the switching pawl 27 is forced by a spring 38 to press in close contact against the boss 30, and manual-automaticswitching is effected by the engagement and disengagement of the said pawl tip with and from a slot 39 in boss 30.

Referring to FIGS. 6, 7, and 8, When the automatic operation cam 29 is not inserted as shown in FIG. 6, the tip of the follower arm 28 passes the bottom diameter of the automatic operation cam 29 and is shifted to the left; an adjustable stop 49 of the switching pawl 27 strikes an edge 41 of the automatic operation base plate 31; the switching pawl 27 is disengaged from the slot 39; the automatic operation arm 26 becomes free to rotate; and the mechanism is then in the manual operation condition.

Then, if a cam cover 42 is opened, an arm 46 supported pivotally on pin 45 of the automatic operation base plate 31 is pushed in the direction of the arrow in FIG. 7 by a protruding arm 44 provided on a hinge 43, and a roller 36 is shifted to the outer side of the outer periphery of the automatic operation cam 29. The insertion of the automatic operation cam 29 is thereby facilitated. At the same time, the switching pawl 27 engages with the the slot 39; the follower arm 28 and automatic operation arm 26 are locked integrally with each other; and the operation becomes automatic. Stop 40 is so adjusted that the said engagement is maintained constantly while the automatic operation cam 29 is being used, as shown in FIG. 8.

The details of the speed-changing mechanism of the automatic operation cam device will be more apparent by reference to the following detailed description. A cam shaft 48 is inserted rotatably in a vertical position in the center of the automatic operation base plate 31, which is fixed, by means of screws 47 to the machine arm 1. A lock pin 49 and a snap ring 50 of the automatic operation cam 29 are provided on the upper protruding end, onto which the automatic operation cam 29 is fitted, of said cam shaft 48. A small spiral gear 53 with an inclined angle is fixed by a pin 51 and nut 52 to the lower part of the said cam shaft 48. In an extended boss 54 on the lower face of the base plate 31, a

free-wheel shaft 55 is" supported rotatably'on a hori zontal axis, and at one end thereof, opposite gear 53, a large spiral gear 56 with an inclined angle is enmeshed at right angles with said gear 53, said gear 56 being fixed by a pin 57 and a nut 58 and transmitting the rotational motion of the free-wheel shaft 55 to the cam shaft 48. At the same time, the inclined angle of said gear 56 being approximately 70 degrees or more, said gear 56 cuts off any transmission of rotational motion from the cam shaft 48 to free-wheel shaft 55.

The other end of the free-wheel shaft 55 is provided with free-wheel plates 61 and 62, both of the same operational direction, with a spacer 63 disposed therebetween, each of said plates having two rollers 59 and two springs 60. Said plate 61 is fixed to the boss 54 by a knock pin 64 and screws 65. One end 68 of a forked rod. 67 is supported pivotally by a pin 69 and a nut 70 to the lower protruding end 66 of the plate 62. The end face of the assembly is closed by a washer 71 and a screw 72. The fork prongs 73 of the forked rod 67 are engaged with a triangular cam 74, which is constructed integrally as a single piece with gear 9 and triangular cam 10. The rotation of the triangular cam 74 causes the forked rod 67 to oscillatev and, simultaneously, causes the lower end boss 75 to be guided, through a slide block 77 supported pivotally on a pin 76 screwed in and fixed to said boss 75, by a groove 79 in a pattern guide bracket 78 and to slide along the direction of said groove 79.

The guide bracket 78 has a hollow shaft 80, which is supported by arm 1 on the same axis as the shaft 16 of the zigzag control knob, and is operated by a pattern control lever 82, which is fixed by screws 81 to the shaft 80 extending out to the front face of arm 1. Pin 83 is a stop, and poppet pin 84 and spring 85 are a click-stop or poppet lock for lever 82. A spring washer 86 placed at the interior surface of the arm 1 for hollow shaft 80 and a spring washer 87 placed at the rear side of arm 1 for the zigzag knob shaft 16 enable both said shafts to be operated independently without mutual interference.

If the groove 79 of the pattern guide bracket 78 is adjusted by the manipulation of a pattern control lever 82, as shown in FIG. 10, forked rod 67, through the action of the triangular cam 74 and guide groove 79, will undergo only an oscillatory motion with the pin 69 as the axis of oscillation, and the cam shaft 48 Will notundergo' any rotational motion whatsoever, the rotational ratio thereof with.respect to the main shaft 2 being zero. However, when adjustment is made 'as shown in FIG. 11, forked rod 67, at the same time that it is oscillated by the triangular cam 74, is made by the guide groove 79 to undergo a reciprocating motion as shown by the arrow. The resulting'oscillation ofthe plate 62 causes the shaft 55, through the free-wheel 62 and re verse-rotation-preventing free-wheel 61, to rotate intermittently in one direction and to transmit a rotation to the cam shaft 48 through the

gears

56 and 53. This rotation can be varied freely as necessary by-the manipulation of the lever 82, which motion is converted into adjustment of the directional angle of the guide groove 79 of the guide bracket 78, from zero to anyyalue within the predesigned range limited by the stop 83. Accordingly, the rotational ratio between the cam shaft 48 and main shaft 2 can be varied steplessly from zero, within the above-mentioned range. Moreover, through the use of the mechanism described above of this invention, speed. variation can be attained simply and freely. At the same time, rotation is effected quietly and reliably by the free-wheeling mechanism, and any brakeless motion of the cam shaft 48 in the rotational direction is prevented by the

gears

53 and 56. Furthermore, through the use of the triangular cam 74 of coaxially, symmetrically opposite profile with respect to the triangular cam 10 for oscillating the needle bar, the possibility of rotation of automaticoperation cam 29 during the cloth-piercing motion of the needle is eliminated, yet the balance of the forked rods 11 and 67 with respect to vibration is excellent. Accordingly, the device of this invention is an ideal speed-varying, automatic cam device for usewithin an automatic zigzag sewing machine.

While only one particular embodiment of the present invention has been described herein, it will, of course, be understood that the invention is not to be limited to the details described herein, since many modifications may be made in the said details without departing from the nature and spirit of the invention, and it is intended that all such modifications shall be covered by the ap pended claim.

What we claim is:

In a zigzag sewing machine having a maindrive shaft operatively connected to a needle bar controlled by a pattern cam for automatically guiding the needle bar through a zigzag movement, and an. arrangement for controlling the speed of said cam, comprising in combination; first and second mutually parallel shafts respectively disposed above'and below and normal to said drive shaft, first and second control cams secured in substantially balanced and spaced relation on said first shaft, a first intermediately pivoted, bifurcated lever having a bifurcated portion engaged on one of said cams and operatively connected to said needle bar for affording a lateral oscillatory movement to said needle bar, a second bifurcated lever having a bifurcated portion engaged on said other control cam, a one-way drive mechanism operatively connected to said second bifurcated lever for operative connection to said pattern cam and for providing unidirectional and intermittent speeds of movement to the pattern cam, and a control mechanism on said second bifurcated lever for controlling the angular throw of said second lever for obtaining variations of the speed ratio between the main drive shaft and the pattern cam, said control mechanism including a slide block pivotally mounted on said second lever with an axis of rotation parallel to said first and second shafts, a bracket on said second shaft and rotatable therewith and. reciprocably receiving said slide block, means connected to saidsecond shaft for rotating said shaft and bracket about the longitudinal axis of said second shaft to change the angular position of said bracket and thereby change the motion of said slide block to permit varying degrees of oscillation of said second bifurcated lever from zero to a predetermined value and thereby varying the speed of rotation of the pattern cam.

References Cited in the file of this patent UNITED STATES PATENTS- 2,757,626 Fujita Aug. 7, 1956 2,832,302 Gegauf Apr. 29, 1958 2,854,935 Benink et al. Oct. 7, 1958 2,900,937 Gegauf Aug. 25, 1959 2,905,119 Home Sept. 22, 1959 2,929,344 Theenhausen et a1. Mar. 22, 1960 2,966,868 Theenhausen et al Jan. 3, 1961