US3039323A

US3039323A - Cam control assembly

Info

Publication number: US3039323A
Application number: US827378A
Authority: US
Inventors: Mori Miyoshi
Original assignee: Individual
Current assignee: Individual
Priority date: 1958-10-15
Filing date: 1959-07-15
Publication date: 1962-06-19
Anticipated expiration: 1979-06-19

Description

June 19, 1962 MlYOSHl MORI 3,039,323

CAM CONTROL ASSEMBLY Filed July 15, 1959 2 Sheets-Sheet l June 19, 1962 MlYOSHl MORI CAM CONTROL ASSEMBLY 2 Sheets-Sheet 2 Filed July 15, 1959 United States Patent 3,039,323 CAM CONTROL ASSEMBLY Miyoshi Mori, 40 Ganjiyama, Ohn, Japan Filed July 15, 1959, Ser. No. 827,378 Claims pricrity, application Japan Get. 15, 1958 4 Claims. (Cl. 74568) This invention relates to a zigzag sewing machine, and has for its object to provide a zigzag sewing machine equipped with an improved pattern cam assembly con sisting of a plurality of superposed cams for controlling the zigzag swing motion mechanism, and in which the configuration of the combined controlling cam may readi 1y be varied for any selected one of the stitch patterns without detaching or changing any of the cam elements.

Another object is to provide a simple, practical and reliable arrangement for accomplishing the foregoing.

According to this invention, the zigzag sewing machine comprises a needle bar supported by swing arms, a zigzag swing motion mechanism driven from an upper shaft of the machine and having a cam follower, and a controlling cam assembly engaging with said cam follower, which cam assembly consists of a plurality of superposed plate cams mounted on a cam shaft, such as a basic cam disc, a main cam disc radially shiftable relative to said basic cam disc, and an auxiliary cam or cams so mounted on a supporting disc to be rotatable on an axis parallel to said cam shaft according to rotation of said cam shaft, thereby to vary the combined outer configuration of the controlling cam assembly.

The accompanying drawing will serve to illustrate a specific embodiment of my invention, in order that its utility and functioning Will be thoroughly appreciated. It will be understood, however, that this is by way of illustration only and is not to be taken as limiting the invention in any Way.

In the accompanying drawings:

FIGURE 1 is a perspective view of the driving mechanism of the zigzag sewing machine equipped with the controlling cam constructed according to this invention;

FIGURE 2 is a section taken along line II-II of FIGURE 1;

FIGURE 3 is an end view of FIGURE 2 as seen in the direction of arrow A;

FIGURE 4 is an exploded perspective view of the controlling cam assembly shown in FIGURE 2;

FIGURE 5 is a cross section showing the oneway driving connection of the controlling cam mechanism;

FIGURE 6 is a similar section showing the oneway driving connection of the dial control;

FIGURE 7 is a diagrammatic view showing the outer configuration of the control cam as set for straight stitching; and

FIGURE 8 is a similar view showing one example of change of the outer configuration of the controlling cam adjusted for zigzag stitching.

Referring to FIGURE 1, the reference numeral 1 designates the upper shaft of the sewing machine. This shaft 1 drives a triangular cam 4 through worm gears 2 and 3 at a reduction ratio of 1/2. A vertical shaft 5 fixed to the machine frame carries an adjusting arm 6, to which is pivotally mounted a forked arm 7. Said arm 7 is provided on its upper surface with a curved slot and on its lower surface with a straight slot. The triangular cam 4 engages with said straight slot and, according to rotation of the cam 4, the forked arm 7 is oscillated in a horizontal plane. Said triangular cam 4 is so shaped that the forked arm 7 is stopped at interval for a predetermined period of time. Engaged with the upper curved slot of the arm 7 is a square block 8 on the free end of a driving link 9 which is pivotally connected to the free end of an arm 11 fixed to a vertical shaft 10. The square block 8 carries a roller (not shown) which is engaged by a slot formed at the free end of a zigzag width adjusting arm 12, whereby the motion of the free end of the driving link 9 is limited. To said link 9 is connected a bracket 13 which carries a connecting rod 14 for oscillating swingable arms 15 supporting a needle bar 16 and a needle 17. By the oscillating motion of the forked arm 7 according to the rotation of the triangular cam 4, the arm 11 is oscillated through the link 9, so that the swing arm 15 is oscillated through the bracket 13 and the connecting rod 14. Similar oscillating motion is transmitted to the shuttle 20 through a connecting rod 18 and an arm 19. A bevel gear 21 is engaged with the root of the zigzag width adjusting arm 12 and is in mesh with another bevel gear 22. The latter is fixed on a shaft for manual adjustment of the width of the zigzag stitch. A worm 23 is fixed on the upper shaft 1 and meshes with a worm wheel 24 which has a suitable reduction gear ratio. A controlling cam assembly is generally designated by the numeral 25. A cam follower 26 having the height equal to the whole thickness of the assembled cams and supported by arms 27 and 28 is normally held pressed against the outer peripheral face of the cam assembly by means of a spring (not shown). Said arms 27 and 28 are secured to a vertical shaft 29. This shaft 29 is loosely mounted to a switching frame 30 which is in turn loosely mounted on pin 31 fixed to the machine frame. The frame 30 is provided with an operating handle 32 which is actuated when necessary to pull the follower 26 out of engagement with the cam assembly 25 when it is desired to change the cam configuration. A fork ended link 33 is connected at one end to the upper end of the shaft 29 and at the other end to the arm 12. By this connection the motion derived from change of the configuration of the cam assembly 25 is transmitted to the zigzag width adjusting arm 12 through the follower 26, arms 27, 28 and the shaft 2?.

According to this invention, in order to fulfil the above mentioned objects, the cam assembly 25 is constructed and arranged as follows:

Referring to FIGURES 2 and 4, the worm wheel 24 which is in mesh with the worm 23 rotating with the upper shaft 1 is loosely mounted on a shaft 37 securely mounted on the machine frame 35 by means of a set screw 36, and is provided with pins 38 secured thereto for driving connection of a cam supporting disc 39. This disc 39 has a boss provided with holes 40 for engagement with said pins 38 on the worm wheel 24. The disc 39 has on the other end an integral stud 41 which is inserted into a central bore 43 formed in a cam shaft 42. This shaft has on its inner end a main or sun gear 45, and the outer endis journalled in the machine frame. Meshing with said main gear 45, there are four planetary pinions 46, 46' having secured thereto four auxiliary earns 47, 47' .which have speed increasing gear ratio of 2:1. While four pinions and four auxiliary cams are shown by way of example, it is to be noted that the invention is not limited to the number of the pinions and cams. superposed upon said

auxiliary cams

47, 47 there is a circular basic cam 48 mounted on the cam shaft 42 and connected to the supporting disc 39 by means of

studs

49, 49 and nuts i), 50" the basic cam 48 having same diameter as that of the supporting disc 39 and being fixed relative to each other with respect to rotation. The pinions 46 and auxiliary cams 47 are arranged around the cam shaft and are respectively rotatable around said studs 49 by rotation of the main gear 45. Radius of curvature R (FIG. 4) is made equal to the radius of curvature of periphery of each of the supporting disc 39 and the basic cam disc 48. This basic cam disc 48 has a central bore S1 receiving the cam shaft 42. The inner wall of said bore is provided with a gradually enlarging recess 52, into which are inserted a spring 53 and a ball 54 as shown in FIGURE 5. By such arrangement, when the basic cam disc 43 is rotated in the counterclockwise direction as seen in FIGS. 4 and 5 the cam shaft 42 is also rotated in the same direction, whilst when the disc 48 is rotated in the reverse direction the cam shaft 42 is never rotated and remains stationary. The basic cam disc 48 has a pin 55. A main cam disc 58 superposed upon the said basic cam disc 48' has a radially arranged oblong slot 56 engaging with said pin 55, and there is a circular bore 57 of which center is eccentric to the outer diameter, the eccentricity being shown by L. A main cam guide disc 60 which has a circular boss 5% engaging with said circular bore 57 of the main cam disc 58. The cam shaft 42' is inserted through the central bore of the guide disc 60, and the latter is secured thereto by means of a set screw 61. The outer diarneter of the main cam disc 58 is equal to the outer diameter of each of the cam supporting disc 39 and the basic cam disc 48. The outer periphery of the main cam guide disc 60 is concentric with the central bore thereof, whilst the center of the circular boss 59 is eccentric to the center of the central bore. A leaf spring 62 prevents the axial vibration of the cam shaft 42. An indicator disc 63 is secured to said cam shaft 42 and bears the stitch pattern marks. An adjusting knob 64 is connected to the cam shaft 42 in such manner that oneway rotation only is transmitted to the cam shaft 42, as by means of a oneway driving connection including a spring 65 and a ball 66 (see FIG. 6), which are similar to those shown and described with reference to FIGURE 5. Said adjusting knob 64 is prevented from being detached from the cam shaft 42 by means of a cover ring 68 made of transparent plastic material which is secured to the machine frame by set screws 67.

The operation of this invention is as follows: The rotation of the worm gear 24 which is driven from the worm 23 on the upper shaft 1 at a predetermined reduction ratio is transmitted to the cam assembly 25 consisting of the

auxiliary cams

47, 47 the basic cam disc 48, and the main cam disc 58, in unison, through the cam supporting disc 39. Upon the rotation of said cam assembly, the motion of the follower 26 engaging with the peripheries thereof will be transmitted to the zigzag stitch swing motion mechanism as hereinbefore described with reference to FIGURE 1. Now, when the knob 64 is rotated in the direction of arrow in FIGURE 6, the cam shaft 42 is rotated, whereby the eccentric main cam disc 58 guided by the eccentric boss 59 of the guide disc 60 on the shaft will be radially shifted along the pin-andslot connection 5556-, bringing a phase displacement. At the same time, the pinions 46-, 46 meshing with the main gear 45 on the shaft 42 and carrying the auxiliary cams 47, 47' will perform a planetary motion like movement relative to the shaft 4 2, each pinion rotating on its own axis 49.

Referring to FIGURE 4, the radius of curvature R of the auxiliary cam 46 (and R of 46) is made equal to the radius of the peripheral circle of each of the cam supporting disc 69, the basic cam disc 48 and the main cam disc 58, whilst the remaining peripheral face of the auxiliary cam 46 (46') has smaller radius of curvature B (B), and said larger radius of curvature and the smaller radius of curvature are arranged in such relation that the dimension B is larger than b relative to the center of the pinion 46, as shown in FIGURE 4. By such arrangement, according to partial rotation of the knob 64, the combined cam face configuration of the main cam disc 58 and the cams 47 (47' may be brought into exact coincidence with the configuration of the basic cam disc 48 as shown in FIGURE 7, and it may also be possible to make substantially indefinite number of changes of combined cam configuration by the manual operation of the said adjusting knob 64 through the radial displacement of the main cam disc 58 and by individual rotation of the auxiliary earns 47 (47 When the combined cam configuration is in coincidence with the basic cam disc 48 which is a true circle as shown in FiG-URE 7, it will be obvious that the straight stitch may be obtained. On the other hand, as seen from FIG- URE 8 by way of example, when the phases of the main cam disc 58 and of the auxiliary cams are displaced relative to the basic cam disc 48, desired zigzag stitch may be obtained as shown at the bottom of FIGURE 8, the pattern of zigzag stitch being variable for wide range according to the variable configuration of the combined cams which are determined by angular position of the adjusting knob 64. The stitch patterns determined by various configurations of the combined cams are indicated on the indicator disc 63. During the operation of the machine, the cam assembly together with the cam shaft 42 and the said indicator disc 63 secured thereto are rotated in unison in the direction of arrow in FIG- URE 5, but the adjusting knob 64 remains stationary by reason of the free wheeling connection as shown in FIGURE 6.

For changing the stitch pattern by displacement of the combined cam elements, keeping the machine stationary, the adjusting knob 64 is manually rotated to bring the selected one of the stitch pattern marks on the indicator disc 63 into register with the index mark 6-9 on the transparent cover ring 68. It will thus be seen that according to this invention the cam assembly may readily be adjusted and set to the position allotted for the selected one of the stitch patterns.

Whatl claim is:

1. A controlling cam assembly comprising: a supporting shaft means for rigid mounting at a preselected place of carn assembly operation; a cam supporting disc mounted for rotation on said supporting shaft, a cam shaft, having an integral main gear at one end, rotatably supported and axially attached at the gear and by said cam supporting disc, said cam shaft being journalled at the other end for radial support; a plurality of planetary gears adapted to mesh with. saidmain gear for simultaneous rotation thereby; a plurality of annular auxiliary cams having similar peripheral cam surfaces, each said auxiliary cam being rigidly attached to an end of a planetary gear and having portions of the peripheral cam surface with different radii of curvature, a basic cam disc having approximately the same diameter and peripheral cam surface as the support cam disc and defining a center hole for engaging said cam support disc on the cam shaft, a plurality of spacing and securing means rigidly spacing and securing the basic cam disc to the supporting cam disc for rotation about the cam shaft, and respectively securing therebetween the planetary gears and attached annular auxiliary cams for rotation about said respective spacing and securing means, said gears and attached auxiliary cams being radially and circumferentially spaced apart equally by said spacing means and positioned with respect to the supporting and basic cam discs for at least one portion of the peripheral cam surface of each annular auxiliary cam to extend beyond the peripheries of said support and basic cam discs, whereby the auxiliary cams are rotatable with the supporting and the basic cam discs around the cam shaft and each auxiliary cam is rotatable around its spacing and securing means by the rotation of said cam shaft and integral main gear and planetary gears for adjustment of the peripheral cam surfaces of said auxiliary cams with respect to the peripheral cam surfaces of the supporting and basic cam discs.

2. A controlling cam assembly as recited in claim 1, wherein an adjusting knob is mounted on the outer end of the cam shaft through a oneway driving connection.

3. A controlling cam assembly as recited in claim 1, wherein a portion of the peripheral cam surface of each of the auxiliary cams has the radius of curvature equal to that of the basic cam disc.

4. A controlling cam assembly as recited in claim 1, wherein the basic cam disc is mounted on the cam shaft through a oneway driving connection, an eccentric pin mounted on said basic cam disc parallel with said cam 6 shaft, and a main cam disc defining a radial slot and an eccentric outer bore adapted to allow the free passage of said cam shaft is superposed upon said basic cam disc, said eccentric pin engaging in said radial slot to connect said main cam disc in radially shiftable rotation relative to the'basic cam disc.

References Cited in the file of this patent UNITED STATES PATENTS 1,141,504- Street June 1, 1915 1,145,337 Street July 6, 1915 1,460,651 Hall July 3, 1923 2,250,696 Avis July 29, 1941 2,594,911 Goff Apr. 29, 1952 2,900,837 Brandt Aug. 25, 1959 2,900,937 Gegauf Aug. 25, 1959 2,903,528 Kuhn Sept. 8, 1959