Patent Publication Number: US-4368681-A

Title: Pattern selecting mechanism of a sewing machine

Description:
DESCRIPTION OF THE INVENTION 
     The invention relates to a pattern selecting mechanism of such a sewing machine in which the single operating dial is manually operated in one rotation thereof to vary the feeding movement with a specific cycle in relation to the patterns, thereby to produce further different patterns to meet the requirements of the machine users. 
     There have heretofore been proposed such a sewing machine in which a dial is rotated through a plurality of angular positions. However, it was absolutely impossible to vary the fabric feed with a specific cycle in one rotation range for producing many kinds of the super patterns. 
     The present invention has been devised to eliminate disadvantages in the prior art. It is a basic object of the invention to provide a device which is easy in operation. 
     It is another object of the invention to provide a device which may produce various kinds of the super patterns of stitches. 
     Many other features and advantages of the invention will be apparent from the following description of the invention in reference to the attached drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 shows a perspective view of relative mechanism housed in a top of a sewing machine, 
     FIG. 2 shows a front view of a portion of the above, 
     FIG. 3 shows an explanatory view of the relationship between one part of the mechanism shown in FIG. 2 and a pattern indicating device, 
     FIG. 4 shows a side view, partially in section, of a feed dial mechanism, 
     FIGS. 5 and 6 show perspective exploded views of relative mechanism, and 
     FIGS. 7 to 9 show explanatory views of actuation of relative mechanism. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The invention will be discussed in reference to the attached drawings. The numeral 1 shows a main shaft rotatably supported in a machine housing 2. The numeral 3 is a worm wheel which is mounted on a shaft 4 mounted in the machine housing 2 transverse to with the main shaft 1, and which is in mesh with a worm 5 secured on the main shaft 1 for reducing rotation thereof 1/integer of rotation of the main shaft 1 (in this embodiment, reduction is 1/6). The numerals 7 and 8 are pattern cam group 7a, 7b . . . for changing the amplitude of the needle bar 23 and the feed changing cams 8a, 8b . . . , those being formed integrally with the worm wheel. The numeral 9 denotes a selecting dial shaft rotatably supported in the machine housing 2. The numeral 10 designates a pattern selecting dial fixed to the selecting dial shaft 9 at its end portion disposed outside of the machine housing 2. The dial 10 is arranged such that it can be rotated to an exact position by association with a selecting plate 11 formed with a plurality of cutouts 11a on its periphery, which is fixed to the machine housing 2, a setting pin 12 which is held within the pattern selecting dial 10 and can engage in any selected cutout 11a, and a setting spring 13 pressing the pin 12. The pattern selecting dial 10 can be rotated through a plurality of angular positions, and in this embodiment it can be rotated through a first range of angular positions and a second range of angular positions following the first range. 
     The numerals 14 and 15 denote respectively a cylindrical pattern cam selecting cam body and a feed setting disk cam body which are fixedly mounted on the pattern dial shaft 9 inwardly of the machine housing 2. The pattern cam selecting cam body 14 is provided at its front side with a drum 16 for winding a later mentioned string 86 thereon, and on its rear side with a pattern selecting cam 17 having a side cam face 17a inclined in an axial direction, stepped side a cylindrical cam face 17b extending in a radial direction (FIG. 5). The feed setting disk cam body 15 is provided with a super pattern selecting cam 18 comprising a spiral groove at its front side, and with a button hole stitching cam 19 having a cam face extending in a radial direction at its rear side. 
     The shape of the super pattern selecting cam 18 will be explained in detail with reference to FIG. 7. With respect to a first rotation range of the pattern selecting dial 10, the feed setting cam body 15 is formed with a large radius cam groove portion 18a of constant radius in such a manner that a later mentioned switching arm 32 (refer to FIG. 5) engaging the super pattern selecting cam 18 is maintained at the left-most position thereof. With respect to a second rotation range, a small radius cam groove portion 18b is formed following the large radius cam groove portion (FIG. 7) 18a in such a manner that the switching arm 32 is maintained at the right-most position thereof. The numeral 20 in FIG. 5 designates an amplitude control cam body provided with an amplitude control cam face 20a which is pivoted to the winding drum 16 of the pattern cam selecting cam body 14 via a seat plate 21. 
     The numeral 22 is a needle bar supporter which is pivoted to the machine housing turnably to the right and left and supports a vertically movable needle bar 23 at its side. The numeral 24 is a needle bar turning arm which is pivoted at its one end to the needle bar supporter 22 by a pivot pin 25 having an axis coinciding with the axis of the needle bar 23, and whose follower 24a formed at the other end engages a desired cam of the cam group 7. The numeral 26 is a selection adjusting arm whose base 26a is fixed to a rear face of the needle bar turning arm 24, and a follower 27 projecting upwardly from its end engages the pattern selecting cam 17. The follower 17 is biased by a spring (not shown) to contact the pattern selecting cam 27. The numeral 28 is an amplitude adjusting arm whose base 28a is fixed to a front face of the needle bar turning arm 24, and a follower 29 projecting upwardly from its end engages a cam face 20a of the amplitude control cam body 20. The follower 29 is a biased by a spring (not shown) to contact the amplitude control cam face 20a. The numeral 30 is a U-shaped super pattern selecting arm which is mounted on the shaft 4 and holds the pattern cam group 7 and the feed changing cam group 8 inside thereof. The numeral 31 is a super pattern switching cam body mounted on the shaft 4 between a back side 30a of the supper pattern selecting arm 30 and the feed changing cam group 8. The cam body 31 is formed with a circumferentially extending cam 31a having axially offset cam faces 31b, 31c and an inclined cylinder face 31d therebetween. The 31e is an angular portion projecting from the lower end of the projection cam 31a. The numeral 32 is a switching arm and the selecting dial shaft 9 passes through an oblong slot 32a formed therein and the switching arm 32 is restrained in the axial direction by a snap ring 33. A follower 34 provided at one end of the switching arm 32 engages the super pattern selecting cam 18, and the other end of the switching arm 32 is mounted on a pin 35 on the super switching cam 31 and is restrained in the axial direction by a snap ring (not shown). The numeral 36 is a feed adjusting arm which is pivoted at a base 36a on a pivot shaft 37 at the back side 30a of the super pattern selecting arm 30 and restrained against axial movement by a snap ring 38. The numeral 39 is a super pattern feeding pawl which is housed inside of the base 36a and is mounted on a shaft 41 by a snap ring 40 and is pushed backwardly by a compression spring 42 of weak pressure. A projecting piece 39a at the lower part of the pawl 39 is adapted to engage the supporting faces 31b, 31c, and the follower 39b is adapted to engage the feed adjusting cam group 8. The numeral 43 is a feed setting arm mounted on the shaft 4, a pin 44 of which is engaged with the button hole stitching cam 19. Detailed description thereof is omitted because of no relation with the invention. 
     The numeral 45 is an amplitude adjusting plate which is transverse to the main shaft 1 and is provided with an amplitude dial shaft 46 rotatably supported in the machine housing. The numeral 47 is an amplitude dial fixed to an end of the amplitude dial shaft 46 projecting outside of the machine housing 2. The dial 47 is set such that it can be turned exactly by association of a switching plate 48 formed with a plurality of cutouts 48a on its periphery, which is fixed to the machine housing 2, a setting pin 49 which is held within the amplitude dial 47 and engages the cutouts 48a of the switching plate 48, and a setting spring 50 pressing the pin 49. The numeral 51 is an amplitude indicator at the front face of the amplitude dial 47. The numeral 52 is an amplitude arm which can be moved in axial direction by pivoting via a snap ring 55 one end thereof on a pin 53 provided at the front face of the amplitude control cam body 20 and by pivoting via a snap ring 55 the other end thereof on a pin 54 provided at a lower end of the amplitude control plate 45. 
     The numeral 56 is a feed adjuster rotating around a feed adjustor shaft 57 parallel with the main shaft 1. The numeral 58 is a feed adjusting pin provided at a rear end of the feed adjuster. The numeral 59 is a comparatively strong adjustor spring, which is positioned between the feed adjusting pin 58 and the machine housing 2, and biases the feed adjustor 56 to rotate to generate the maximum forward feed (i.e., in the clockwise direction in FIG. 4) around the feed adjustor shaft 57. The numeral 60 is a feed control arm which is fixed via a nut 62 to a feed control rod 61 connected at its upper end to the other end of the feed adjusting arm 36. 
     The numeral 63 is an adjustor rotating plate mounted on the feed adjustor shaft 57 adjacent to the feed adjustor 56, and an abutting screw 65 is set such that it contacts the feed adjustor 56 with a spring (not shown) of weak force, which screw 65 is secured by a nut 64 on a bent piece provided at the top of the adjustor rotating plate 63, and accordingly the adjustor rotating plate 63 is rotated integrally with the feed adjustor 56. The numeral 66 is a pin provided at the lower end of the adjustor rotating plate 63 to run in a circular groove 73a of a later mentioned feed dial shaft 73. The numeral 67 is a feed setting arm to connect the feed setting arm 43 and the adjustor rotating plate 63. Detailed description thereof is omitted because of no relation with the invention. 
     The numeral 68 (FIG. 4) is a feed dial plate secured to the machine housing 2. 69 is a feed dial seat fixed to a rear side of the plate 68 by a screw 70. 71 is a feed dial rotatably provided at a space defined between the feed dial plate 68 and the feed dial seat 69 via a spring washer 72. 73 is a feed dial shaft inserted along holes formed in axes of the feed dial seat 69 and the feed dial 71, and a circular groove 73a formed at one end of the shaft 73 is engaged by the pin 66 of the adjustor rotating plate 63, and a pin 74 provided on the shaft 73 is engaged with a forward feed controlling cam face 71a formed in the feed dial 71 by means of an adjustor spring 59, and the shaft 73 is provided at its other end with a reverse button 75 and a pin 76 projecting therefrom. 71b is a backword feed controlling cam face formed in the feed dial 71 be engaged by the pin 76. 77 is a U shaped pattern switching arm pivoted on a pivot shaft 78 at a rear face of the feed dial plate 68 and being restrained in the axial movement by a snap ring 79. 77a (FIG. 6) is a follower formed at an upper end of the arm 77, and the follower 77a engages the pattern switching cam 71c by means of an appropriate spring mechanism (not shown), which biases the arm 17 toward a circular surface which is formed in continuation to the forward feed controlling cam face 71a of the feed dial 71. 80 (FIG. 8) is a super pattern selecting rod which is pivoted at its upper end on a pin 81 provided on the super pattern selecting arm 30, and a fork 80a on its lower end is mounted on a stepping pin 82 provided on the upper end of the rear branch of the pattern switching arm 77. 
     The numeral 83 (FIG. 3) is a pattern indicating panel secured to a front face of the machine housing 2, displaying the stitch patterns as figures 84 (84a, 84b . . . ) to be selected by rotation of the pattern selecting dial 10. 85 is an indicator of selected patterns laterally moving by means of an appropriate means, e.g., a string 86 which is connected one end to the outer periphery of the winding drum 16, to a position of the stitch pattern corresponding to the rotating position of the drum. 
     Above described device will operate as follows. FIG. 7 shows that in the first rotation range (the range &#34;I&#34; in FIG. 3) of the pattern selecting dial 10, the minimum equal diameter portion 71d of the pattern switching cam 71c of the feed dial 71 is engaged with the follower 77a of the pattern switching arm 77. In this condition, since the follower 34 of the switching arm 32 engages the maximum radius cam groove 18a of the super pattern selecting cam 18, the switching arm 32 is maintained at the left-most position, and the super pattern feeding pawl 39 moves the follower 39b toward a cam 8a of the feed adjusting cam group 8 due to the contact of the support face 31b of the super pattern switching cam body 31 with the projection 39a of the pawl 39. At this time, since the cam 8a and the follower 39b are separated, the action of the cam 8a does not influence the feed adjustor 56. Therefore, the feeding amount can be manually set by the rotation of the feed dial 71. In this case, the rotation of of the feed dial 71 is limited only to the range where the follower 77a of the pattern switching arm 77 engages the minimum equal dialeter part 74d of the pattern switching cam 71c of the feed dial 71. The amplitude of the needle bar 23 is controlled in that the amplitude dial 47 is appropriately rotated to change the engaging position of the follower 29 of the amplitude control arm 28 with respect to the amplitude control cam face 20a of the amplitude control cam body 20. 
     The cylindrical cam face 17b of the pattern selecting cam 17 is provided to engage, during selecting a cam from the pattern cam group 7, the follower 27 of the selection adjusting arm 26 with the cam face thereof and temporarlily separating the follower 24a of the needle bar swinging arm 24 from the outer diameter of the pattern cam group 7. 
     FIG. 8 shows similarly to FIG. 7 that in the first rotation range of the pattern selecting dial 10, the feed dial 71 is rotated from the position shown in FIG. 7 in order to engage the follower 77a of the pattern switching arm 77 with the maximum lift part 71e of the pattern switching cam 71c, and the pattern switching arm 77 is further rotated in the counterclockwise direction than shown in FIG. 7 and the super pattern selecting arm 30 is also rotated in the counterclockwise direction in correspondence with said rotation via the super pattern selecting rod 80, so that the follower 39b of the super pattern feeding pawl 39 is engaged with the cam 8a of the feed adjusting cam group 8, and the feeding amount is automatically set by the displacing amount of the cam 8a. Thus, the so-called super pattern stitch is formed. 
     When the pattern selecting dial 10 is switched from the first rotation range to a second rotation range (the range &#34;II&#34; in FIG. 3), the follower 34 of the switching arm 32 engages the small radius cam face 18b of the super pattern selecting cam 18, as shown in FIG. 9 so that the switching arm 32 is moved to the right-most position, and the super pattern switching cam body 31 is rotated in the counterclockwise direction in correspondence with said movement, and the projecting piece 39a of the super feeding pawl 39 contacts the support face 31c of the super pattern switching cam body 31 by way of the guide face 31d, due to the action of the compression spring 42 and engages the cam 8b of the feed adjusting cam group 8, and concurrently the super pattern selecting arm 30 is also rotated in the counterclockwise direction by the angular portion of the super pattern switching cam body 31, and the follower 39b of the super pattern feeding pawl 39 engages the cam 8b. Thus, the super pattern stitch is formed. In this case, it is necessary to to adjust the feeding device by turning the feed control dial 71 to provide a permissible feeding amount greater than the maximum feeding amount of the super pattern so as to avoid interference of the rotating parts. 
     The projecting cam 31a of the super pattern switching cam body 31 is provided to engage, during selecting of a cam of the feed adjusting cam group 8, the follower 36b of the feed adjusting arm 36 with the cam face thereof and temporalily separate the follower 39b of the super pattern feeding pawl 39 from the outer diameter of the feed adjusting cam group. 
     As mentioned above and according to the present invention, the selecting positions of all the patterns to be selected are not prepared during one turning of the pattern selecting dial 10 as in the prior art. This dial is turned more than one time. Within the first range of rotation of the dial only the straight stitch and the zigzag stitches can be selected. Within the second range of rotation, the straight stitch and the zigzag stitches which have been selected at the same phase during the first range of rotation are not changed in the amplitude, but the super stitches in which the fabric feed as varied at a fixed cycle for various stitches are formed. In addition, the super stitches of the straight stitch and the zigzag stitches at the same phase may be formed even within the first range of rotation of the dial 10 by rotating the feed dial 71 which is provided with the feed adjusting cam selecting device, i.e., the pattern switching arm engaging the pattern switching cam provided at the feeding dial which controls obliquity of the feed adjustor, the super pattern selecting arm associating with said arm and pivoting the super pattern feeding pawl, and the feeding dial. Therefore, the present invention may carry out various kinds of the stitch patterns by simple operation of the feed dial.