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Publication numberUS3596618 A
Publication typeGrant
Publication dateAug 3, 1971
Filing dateApr 17, 1970
Priority dateApr 17, 1970
Publication numberUS 3596618 A, US 3596618A, US-A-3596618, US3596618 A, US3596618A
InventorsGoldbach Henry T, Graft Robert W, Hauf Robert C, Molnar James V
Original AssigneeSinger Co
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Automatic buttonhole mechanisms for zigzag sewing machines
US 3596618 A
Abstract  available in
Images(4)
Previous page
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Claims  available in
Description  (OCR text may contain errors)

United States Patent [56] References Cited UNITED STATES PATENTS Little Ferry;

[72] Inventors Henry T.Goldbach James V. Molnar, Parsippany; Robert C. 3 H3 537 112/158 :E'g'ifj Gran, 3,503,350 3/1970 Buan et 112/158 .54 7197 1 k 0d t 1 112158 21 AppLNo. 29,622 3 0 6 a d n a s m .m n A r m s m C 1. 1 n me mm .wB R J w m 51 am B 1mm w mw R PA y m o my 7 C mw 1 m 3 n8 Puh AATh e we M d e .W: e L Ha FPA NM 247 [ll ABSTRACT: A buttonhole mechanism having a wheel, which [54] gggsgg gg gggzggtg FOR rests upon the material being sewn so that the wheel turns as fed to rovide sensin ulses at reset in- 5 Claims, 17 Drawing Figs the matenal 1s bemg p g p p tervals whlch control electromechamsms for proper operatlon [52] U.S. 112/158, of a compact buttonholing assembly of a household zigzag 356/167 sewing machine. When an operator sets a single-switching [51] Int. D05b 3/02 device, the buttonholing assembly is coupled to all of the sew- [50] Field of 112/158, ing machine controls requiring variation during the stitching of the buttonhole.

511191 1. new

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PATENTED AUG 3 I97! SHEET 2 BF 4 Fig. 4

INVENTORS.

Henry T. Goldbach Robert W. Graft Robert C. Houf James V. Molnar @l-Mn/ ATTORNEY PATENTED AUG 3am SHEET 3 [IF 4 I57 I43 7 I44 l-153 HI Q Lrsil 4 I I46 2 I47 1* M ,1

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Robert c. Haui, James V. Molnar WITNE'SS: v {j ATTORNEY AUTOMATIC BUTTONHOLE MECHANISMS FOR ZIGZAG SEWING MACHINES BACKGROUND OF THE INVENTION It has long been recognized that a buttonhole may be formed on a zigzag sewing machine having controls for the width and the lateral position of the needle jogging, and controls for the forward and the reverse direction of the feed of the work being stitched by manually setting the various machine controls at each stage of the buttonhole stitch formation, wherein the above buttonhole usually has four parts comprising the opposite ends and the opposite side stitches. With this arrangement, however, buttonhole stitching is a tedious operation and the appearance of the buttonhole reflects the skill and dexterity of the machine operator.

It is also known in the art to provide buttonholing mechanisms associated as a part of a pattern cam arrangement for a needle jogging and work feeding mechanism of the sewing machine for automatically varying the pattern cam operation so as to produce the buttonhole stitch formation. These mechanisms introduce further complexity into the already critical area of the patterning mechanism of a zigzag machine and therefore, involve considerable expense. US. Pat. No.

3,! 13,537 of Bono discloses a zigzag sewing machine having mechanism of the above mentioned type for automatically sewing a buttonhole, whereby a device is slidably attached to the presser foot to move together with the material being sewn betweenan adjustable preset point and a fixed point to obtain the desired size of the buttonhole. The above device controls the operation of the sewing machine during the formation of the buttonhole, whereby a light under the control of the device may be used to excite a photosensitive element to change the operation of the sewing machine from one condi-' tion to another.

A compact buttonholing assembly, which is separate and remote from the needle jogging mechanism of a household zigzag sewing machine, is disclosed ina copending application, Round End Buttonhole Mechanism for Zigzag Sewing Machines, Ser. No. 739,051, filed June 21, 1968, of Blackwood et al., now US. Pat. No. 3,518,954, and assigned to the assignee of this invention. The above buttonholing assembly, upon operator initiation of each half of a buttonhole stitching operation, is driven by a sewing machine actuating mechanism to shift a single-operating member. By the setting of a single-switching device, the operating member is coupled to all of the sewing machine controls requiring variation during the stitching of the buttonhole so as to effect the stitching sequence necessary for the formation of the buttonhole.

SUMMARY OF THE INVENTION This invention relates to a buttonholing mechanism which may be applied to any household zigzag sewing machine having controls for the width and the lateral position of the needle late the above sewing machine controls to effect the stitching sequence necessary for the formation of the buttonhole. A wheel, which rests upon the material, is turned by the feeding motion of the material, whereby the wheel provides sensing pulses at proper points to control electromechanisms for proper operation of a buttonholing assembly. The buttonholing assembly is coupled to the sewing machine controls by the machine operator setting a single-switching device.

It is an object of this invention to provide a buttonholing mechanism for a household zigzag sewing machine which is distinct and preferably remote from the zigzag mechanism of the sewing machine.

Another object of this. invention is to provide a buttonholing mechanism for a sewing machine which is effective when the machine operator sets a single-switching device to automatically control the stitching sequence necessary for the formation of the entire buttonhole so that any other manual manipulation of the buttonholing mechanism is eliminated.

Still another object of this invention is to provide a buttonholing mechanism for a sewing machine which uses the feeding motion of the material as a feedback control of the mechanism so that improper, erratic feeding and material slippage may be compensated for during the formation of the buttonhole.

A further object of this invention is to provide a wheel which translates the linear motion of the material into rotary motion, whereby for a given buttonhole, length, the wheel rotates through a corresponding angular displacement to provide sensing pulses at preset intervals for controlling the formation of the buttonhole to insure that all buttonholes, when desired, may be the same size, and also to prevent over running of the stitches at the completion of the buttonhole.

A still further object of this invention is to provide an optical-electronic sensing device to effect the sewing machine mechanisms for a proper stitching sequence during the formation of the buttonhole.

BRIEF DESCRIPTION OF THE DRAWINGS Having in mind theabove. and other objects that will be evident from an understanding of this disclosure, the invention comprises the devices, combinations and arrangements of parts as illustrated in the presently preferred embodiment of the invention which is hereinafter set forth in such detail as to enable those skilled in the art readily to understand the function, operation, construction and advantages of it, when read in conjunction with the accompanying drawings in which:

FIG. 1 represents a front elevational view of a sewing machine with portions of the machine frame broken away illustrating the buttonhole mechanism of the present invention applied thereto,

FIG. 2 represents an exploded perspective view of the wheel assembly of the present invention,

FIG. 3 represents a fragmentary perspective view of the wheel assembly, such view showing the wheel hub reflective member in its top position directly underneath the light guide,

FIG. 4 represents a fragmentary perspective view of the wheel assembly, such view showing the tab reflective member in its top position directly underneath the lightguide,

FIG. 5 represents a schematic wiring diagram of the electrical circuit for the buttonhole mechanism of the present invention,

FIGS. 6, 7, 8 and 9 represent in sequence, the manner in which the stitching. of a buttonhole is accomplished using the mechanism of this invention,

FIG. 10 represents a fragmentary. perspective view of the buttonholing assembly of this invention,

FIG. 11 represents an elevational view of the cam disk of the buttonholing assembly,

FIGS. l2, l3, 14, 15, 16 and 17 represent in sequence, the manner in which the cam disk is rotated by the pawls of this invention during the formation of the buttonhole.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings, the buttonholing mechanism of this invention is illustrated in FIG. I as embodied in a zigzag sewing machine of the type having a vertical cam stack which forms the subject of the U.S.Pat. No. 2,862,468, Dec. 2, 1958, of R. E. Johnson to which reference may be had for a detailed description. The sewing machine comprises a frame including a bed 11, a hollow standard 12 rising from the bed 11, a bracket arm 13 extending from the hollowstandard l2 and terminating in a sewing head 14 which overhangs the bed 11. Journaled in the bracket arm l3'is a main shaft 15 which carries, a balance wheel 16. A drive motor (not shown) is preferably carried within the rear portion of the hollow standard l2.

Within the sewing head 14, the main shaft carries a conventional crank mechanism indicated generally at 17 which is connected to a stud 18 secured on a needle bar 19 to the lower extremity of which a needle 20 is clamped. The crank mechanism 17 imparts endwise reciprocating motion to the needle bar 19. To provide for zigzag stitching, the needle bar 19 is endwise slidable in a spherical bearing 21 in the lower extremity of the sewing head 14 and is slidably constrained in a similar spherical bearing 22 in a gate 23 which is pivoted in the sewing head 14 in pintles (not shown). A linkage (not shown), which is pivotally connected to the needle bar gate 23, serves to impart to the needle bar gate 23 lateral vibratory movements so as to swing the needle 20 laterally in the formation of zigzag stitches.

Lateral jogging movement is imparted to the needle bar gate 23 by way of the linkage from a needle jogging mechanism (not shown) which includes provision for controlling the neutral position of needle vibration, and provides for the sewing of cam controlled patterns of zigzag stitching, whereby it will be understood, that the buttonholing mechanism of this invention is applicable to any sewing machine having a zigzag mechanism of the type in which the neutral position of needle vibration may be regulated. The needle jogging mechanism is influenced by a front and a rear cam follower lever (not shown) which may be shifted to cooperate with selected ones of a variety of abutment means (not shown) located in the bracket arm 13 by the depression and adjustment of the lateral position of control buttons 24 and 25, respectively. This cam follower position selecting mechanism forms the subject of a copending U.S. Pat. No. 3,503,350, filed Nov. 20, 1967, assigned to the assignee of this invention, to which reference may be had for a detailed explanation thereof.

A handle 26, which is secured to a bight controlling lever (not shown) of the type disclosed in above U.S. Pat. No. 2,862,468, provides a finger grip for effecting bight adjustment.

Cooperating with the needle 20 in the formation of stitches is a conventional loop taker (not shown) which may be driven intimed relation with the needle reciprocation by means connecting the'loop taker with the main shaft 15. Also driven from the main shaft 15 is a work-feeding mechanism (not shown) which may be of the conventional drop feed variety. A feed regulating handle 27 is connected to the work-feeding mechanism to provide operator-influenced control of the stitch length provided by the work-feeding mechanism. The range of adjustment of the work-feeding mechanism is such as to provide for feed of the work in either direction toward or away from the operator with respect to the sewing needle 20.

In the sewing machine, the standard 12 and bracket arm 13 are formed in the front wall with an opening 28 which is bounded by a protruding rib 29. The opening 28 is closed by a cover or escutcheon 30 through which the controls 24 and 25 for cam follower position selection, the controller 26 for the width of zigzag stitching, and the feed-regulating handle 27 project. Any desired indicia may be provided on the cover or escutcheon plate 30 for facilitating the setting of the controls, and as illustrated in FIG. 1, special indicia 31 may be provided to facilitate the settings necessary for use of the buttonholing mechanism.

The construction of the sewing machine thus far described is similar to that described in greater detail in the above referenced U.S. Pat. No. 2,862,468, which is modified to include the cam follower position selecting mechanism which is described in greater detail in the above referenced U.S. Pat. No. 3,503,350, to both of which reference may be had. A detailed description of the buttonhole mechanism of the present invention is set forth below.

The buttonhole mechanism. as shown in FIG. 1, comprises a sensing wheel assembly 32 which provides sensing pulses at preset intervals to an opto-electronic system 72 for controlling the electromechanisms of a buttonholing assembly 90 which is coupled to the sewing machine controls for automatically forming the stitching sequence necessary for the formation of an entire buttonhole. The wheel assembly 32 is connected by a screw 33 to a support bracket 34 which is mounted on the face cover plate 35 of the sewing machine head 14. The support bracket 34 extends outwardly and downwardly from the face cover plate 35, thereby positioning the wheel assembly 32 adjacent to the sewing machine presser foot 36 so that the wheel assembly 32 rests on the material M being sewn.

As shown in FIG. 2, the wheel assembly 32 comprises a barlike support member 37 having a threaded which receives the screw 33 to secure the support member 37 to the support bracket 34. A slide 39 and a spring 40 are positioned within a recess 41 formed in the support member 37 so that the spring 40 engages the slide 39 to continuously force the slide 39 downwardly towards the bottom wall 42 of the recess 41. A cover 43 encloses the spring 40 and the slide 39 within the recess 4!, wherein the spring biased slide 39 is substantially limited to an upward and downward movement. The legs 44 of the cover 43 are positioned over the edges of the support member 37, and a tab 45 of the cover 43 is positioned in a groove 46 formed in the support member 37 so that only a single screw 47, which passes through an aperture 48 formed in the cover 43 and is screwed into a threaded aperture 49 formed in the support member 37, secures the cover 43 to the support member 37.

A freely rotatable wheel 50, which is secured to the support member 37, is used to translate the linear motion of the material M into rotary motion. The perimeter of the wheel flange 51 is grooved to receive a rubber O-ring 52 to provide traction between the wheel 50 and the material M. Detentreceiving holes 53 are formed in a side of the wheel hub 54, near the edge thereof. The holes 53 are closely spaced around a boss 55 formed on the same side of the hub 54, the boss 55 being positioned on a central portion thereof.

A rotatable arm 56, having a perpendicularly extending tab 57, is positioned against the boss 55 with the tab 57 overlying a portion of the perimeter of the hub 54. The arm 56 is resilient so that a detent 58 formed therein may coact with one of the detent-receiving holes 53 to secure the arm 56 to the hub 54, thereby causing the arm 56 to rotate together with the wheel 50. For a given buttonhole length, the tab 57 is moved manually around the hub 54 against the action of the detent means 53, 58 to a desired position, at which point the detent 58 is engaged in one of the holes 53 to hold fast the arm 56 and maintain the tab 57 in the desired position.

A screw 59 secures the wheel 50 and arm 56 to the support member 37. The screw 59 has an enlarged head 60, a threaded end portion 61 and a hub portion 62 located between the head 60 and the threaded portion 62. The screw 59 passes through a stepped hole 63 formed through the center of the wheel 50 so that the screw head 60 is positioned within the larger opening of the hole 63 and below the outer surface of flange 51, as shown in FIGS. 3 and 4, with the hub portion 62 extending through the smaller opening of the hole 63. A hole 64, formed through an enlarged portion of the arm 56, receives the screw hub portion 62 so that the wheel boss 55 and the arm 56 both rest on the hub portion 62. The threaded portion 61 passes through a vertical slot 65 formed in the cover 43. Accordingly, the screw 59 is screwed into a threaded aperture 66 formed through the slide 39 so that the free end of the threaded portion 61 passes through the slide 39 and extends through a vertical slot 67 formed in the back wall of the support member recess 41, whereby slot 67 is parallel to slot 65.

The screw 59 is tightened until the hub portion 62, which is larger than the width of the slot 65, abuts the cover 43. Then, the screw 59 is slightly loosened to permit the screw 59, while holding the wheel 50, to slide up and down in the slots 65, 67 against the pressure of the spring 40 which acts upon the slide 39 in which the screw 59 is secured to limit the up and down movement. This up and down movement allows the wheel 50 to adjust itself to materials of different thickness whereby, due to the pressure of the spring 40, the O-ring 52 will always rest on the material being sewn. Conventional means may be used to retain the screw 59 in the support member 37, such as flattening the free end of the threaded portion 61. If needed, washers 68 may be placed on the screw hub portion 62 between the cover 43 and the arm 56 to position the arm 56 flatly against the wheel boss 55 for better operation of the detent means 53, 58 and also to reduce the friction between the arm 56 and the cover 43 for free rotation of the wheel 50 and arm 56 when they are secured together by the detent means 53, 58.

A reflective member 69, such as a small piece of reflective aluminum foil, is secured by conventional means within a recess 70 formed in the perimeter of the wheel hub 54. Another reflective member 71 IS secured by conventional means on the tab 57. The relationship between the reflective members 69, 71 is such that the reflective member 71 may be positioned directly above the reflective number 69 whereby in this position the reflective members 69, 71 are parallel to each other. The reflective member 71 may be given difi'erent angular displacements from the reflective member 69 by an operator rotating the tab 57 relative to the wheel 50. The angular displacement between the reflective members 69, 71 determines the length of a buttonhole being sewn, where the buttonhole length is equal to the circumferential length of the are on the O-ring 52 located between the reflective members 69, 71.

In order to utilize the wheel assembly 32, as described above, with its reflective members 69, 71, the opto-electronic system 72 was developed using conventional fiber optic strands joined together side by side to form a light guide 73 to conduct light to and from the wheel hub 54. The light guide 73, as shown in FIGS. 1, 3 and 4, contains approximately 32 adjacent fiber optic strands of ten mil fibers held together within a protective covering.

A clip 74 secures the light guide 73 to the wheel assembly cover 43 with the light guide extending downwardly towards the top of the wheel hub 54. An additional clip 75, as shown in- FIG. 1, secures the light guide 73 to the support member 37 so that when either of the reflective members 69, 71 is rotated to its top position on the wheel hub 54, the light guide 73 is held perpendicular to the top positioned reflective member with the end of the light guide 73 being suspended directly above and parallel to the top positioned reflective member. FIG. 3 shows the reflective member 69 in its top position, and FIG. 4 shows the reflective member 71 in its top position.

The light guide 73 is bifurcated within thg sewing machine head 14 so that one branch 76, containing approximately 16 fiber optic strands, terminates at a small light source 77, shown in FIG. 5 which is located inside the bracket arm 13. Though a conventional sewing machine light may be used for the small light source 77, an auxiliary light is preferred because it emits less heat and because it represents an approximate point source for better light intensity at the wheel assembly 32. The other branch 78, containing the remaining approximately l6 fiber optic strands, terminates at a photosensitive transistor 79 hereinafter called a photocell, such as an N PN Planar Silicon Photo-Darlington Amplifier, shown in FIG. 5, which also is located within the bracket arm 13. The photocell 79 may be cemented in a wooden cube which is painted black to allow the photocell 79 to be used at maximum sensitivity without being affected by stray outside light entering at places other than through the light guide 73. The ends of the light guide 73 are capped by dipping them into a Lucite solution and allowing them to dry to yield a low-light loss at each terminus.

With the above arrangement ofthe light guide 73, light from the light source 77 is picked up by the branch 76 and is carried by the light guide 73 to the perimeter of the wheel hub 54. At the instant one of the reflective members 69, 71 passes directly underneath the light guide 73, the light is picked up through reflection off the reflective member by the other half of the fiber optic strands of the light guide 73 which forms the branch 78, and is-carried by the branch 78 to the photocell 79. The electrical circuit, shown in FIG. 5 uses the photocell 79 as a detection device.

As shown above, the light source 77, the light guide 73 and the photocell 79 form the major components of the opto-electronic system 72. Referring to FIG. 5, the photocell 79 also I11- corporates a two-stage amplifier in a Darlington configuration to produce a very high-current gain. Two more stages of amplification in a Darlington configuration were added externally to the photocell 79 in the form of transistors 80, 81 to increase the sensitivity of the overall circuit even more, thereby compensating for the light loss in the fiber optic strands, which is normally 10 percent per foot.

A conventional resistor 82 and a conventional condenser 83 were added to the circuit to permit proper operation of the photocell 79. A conventional resistor 84 and a conventional Zener diode rectifier 85 were added to the circuit for proper voltage regulation. Other conventional components of the opto-electronic system 72, which are needed for proper operation, are a diode rectifier 86 and a condenser 87. The function of the above conventional components in the circuit shown in FIG. 5 is well known in the art, whereby these components are normally used with photocells.

Before describing the remaining components of the circuit shown in FIG. 5, it is necessary for a better understanding of the circuit to discuss first the buttonholing assembly 90. The buttonholing assembly 90 is a modification of the built-in buttonholer of a two-step design described in the above referenced U.S. Pat. No. 3,518,954. The buttonholing assembly 90, shown in FIGS. 1 and 10, is preferably carried in the sewing machine frame within the lower front portion of the hollow standard 12. A generally U-shaped bracket 91 is secured to the standard by screw means 92. A stud shaft 93 is journaled between the walls of the bracket 91. Secured on the stud shaft 93 is a cam disk 94 having a face cam groove 95 formed in the rear wall thereof, as shown in FIG. 11. The stud shaft 93 protrudes through the cover or escutcheon 30 and externally thereof a knob 96 is secured to the stud shaft 93 The knob 96 is preferably formed with a radial tab 97 A single-operating member 98 is slidably secured to the rear wall of bracket 91 and to the stud shaft 93 to constrain the single-operating member 98 to move in a predetermined path. The single-operating member 98 is positioned adjacent to the rear wall of the cam disk 94. A roller follower 99, shown in FIG. 11, is connected to the single-operating member 98 and tracks the face cam groove 95 in the cam disk 94 to impart movement to the single-operating member 98 between two extreme positions along its constrained path.

The single-operating member 98 is formed with a rearwardly extending finger 100 at its upper extremity. The finger 100 is apertured to accommodate a slidable pin 101 which is formed with a pair of spaced annular head flanges 102. A lever 103, which is fulcrummed on a stud (not shown) by which the feed regulating member (not shown) is pivoted to the machine frame, is formed with a clevis 104 on one end thereof through which apertures are formed to receive the pin 101. The finger 100 is positioned between the legs of the clevis 104.

The bracket 91 is formed with an offset arm 105 to which is threaded a fulcrum screw (not shown) for a leaf spring keeper level 106. The spring keeper level 106 includes an upstanding bifurcated am 107 which engages between the head flanges 102 of the pin 10]. Also mounted on the offset arm 105 of the bracket 91 is a stop member 108 formed with an upturned extremity 109 in which a U-shaped aperture 110 15 formed. A

" handle 111, which is secured to the leaf spring keeper level 106 by a screw 112, extends through the U-shaped aperture 110 and thus provides for the setting of two distinct positions ofthe pin 101 relatively to the single-operating member 98.

In both of the possible positions of the pin 101, the pin 101 will be engaged in the aperture of the single operating member 98 and in the clevis apertures of the lever 103, but the handle 111 does provide for an axial shift of the pin 101 into and out of a position of engagement with an aperture which 15 formed in a plate (not shown) which is connected to the feed-regulating member. By this arrangement, the single-operating member 98 is constantly in operative connection with the lever 103 which provides for control of the neutral position of needle vibration during buttonholing, but by way of the handle 111 the single-operating member may be selectively coupled with the feed regulating member. As the single-operating member 98 is shifted between its two extreme positions. the lever 103 is also shifted. thereby alternately causing the release of the rear cam follower lever for an engagement with the abutment means, or the'engagement of the rear cam follower lever to shift the rear cam follower lever out of engagement with the regular abutment means into a special position suitable for producing a portion of the buttonhole.

As shown in FIG. 10, a bellcrank lever 113 is fulcrummed on the stud shaft 93 and has pivoted at one extremity, by a shouldered screw 114, a pawl 115 which is biased by a spring 116 into engagement with the periphery of the cam disk 94. The other extremity of the bellcrank lever 113 is slotted as at 117 and accommodates a pin 118 which extends from a block (not shown) secured to a feed lift actuating pitman (not shown) which imparts a continuous oscillating motion to the pawl 115. The cam disk 94 is moved by the continuously moving pawl 115. Since the cam disk 94 is driven by the upward movements of the feed lift pitman, and since such feed lift actuation is conventionally timed to occur as the needle 20 emerges from the material M, the increments of motion of the cam disk 94, when driven, will occur while the needle 20 is out of the material M.

The construction of the buttonholing assembly 90 thus far described is similar to that described in greater detail in the above referenced patent application Ser. No. 739,051 to which reference may be had. The main difference between these buttonholing assemblies is in the construction of the cam disk, whereby the cam disk of U.S. Pat. No. 3,518,954 has ratchet teeth cut in only the second and fourth quadrants to perform an operation that is all purely mechanical. To form a buttonhole according to the above U.S. Pat. No. 3,518,954, the operator sets the sewing machine controls to engage the mechanism of the buttonholer and turns a dial on the sewing machine standard to a first indicated position to bring the ratchet teeth of the second quadrant into cooperative relationship with the driving pawl. Upon running the machine, the pawl coacts with the first set of ratchet teeth to rotate the dial 90 to a first stop position, thereby completing the rounded top of the buttonhole. similar to that shown in FIG. 6. The machine continues sewing down the left-hand side of the buttonhole until the desired length is reached. similar to that shown in FIG. 7, at which point the operator again turns the dial 90 to a second indicated position to bring the ratchet teeth of the fourth quadrant into cooperative relationship with the driving pawl. The pawl coacts with the second set of ratchet teeth to rotate the dial another 90 to a second stop position, thereby finishing the bottom of the buttonhole, similar to that shown in FIG. 8. The machine continues sewing up the right-hand side of the buttonhole until the buttonhole is finished, similar to that shown in FIG. 9, at which point the operator must watch and stop the machine, otherwise the top of the buttonhole will be overrun.

The modified cam disk 94 of the present invention has ratchet teeth groups 119 and 120 arranged almost all around the cam disk periphery, except for two plain peripheral surface spots 121, 122 approximately 180 apart. Each of the diametrically opposed spots 120. 121 was formed on the cam disk 94 by omitting one tooth cut therein. With reference to FIG. 11, the cam groove 95 in the cam disk 94 was not modified, whereby a gradual change of the cam groove radius is provided, which is tracked by the roller follower 99 during each interval of cam drive by way of the pawl 115, i.e., with the cam groove 95 decreasing in radius within the portion 123, located between points a and b, while the ratchet teeth group 119 IS engaged by the pawl 115, and the cam groove 95 increasing in radius within the portion 124, located between points and d, while the ratchet teeth group 120 is engaged by the pawl 115. Each portion of the cam groove 95 tracked by the roller follower 99 between the quadrant portions 123 and 124 may be substantially of constant radius, where the portion 125, located between points d and a, has a larger radius than the portion 126, located between points b and c. If preferred, the radii of portions 125, 126 may be increased or decreased only slightly to remove the lost motion between the parts before the cam groove portions 123, 124 become effective.

A second pawl 127 was added to further modify the buttonholing assembly 90. The pawl 127 is positioned adjacent to the pawl 115 and is pivoted at one end of the bellcrank lever 113 by the shouldered screw 114, similar to pawl 115. The pawl 127 is biased by a spring 128 towards the periphery of the cam disk 94 so that at the time the pawl 127 engages the cam disk 94, the claw of the pawl 127 is mechanically ahead of the claw of the pawl 115 by two ratchet teeth of the cam disk 94. However, the pawl 127 is normally held off the ratchet teeth groups 119, 120 by a pin 129 extending through a slot 130 formed in the pawl 127. The slot 130 permits continuous oscillating movement of the pawl 127 by the bellcrank lever 113 while the pawl 127 is being held off the cam disk 94 by the pin 129. The pin 129 is secured to the end of a plunger 131 of a solenoid 132, whereby a spring 133 biases the plunger 131 into an extended position outwardly of the solenoid so that the pin 129 is engaged in the slot of pawl 127.

An aperture 134 is formed in the pawl 127 to receive a pin 135 which is secured to the single-operating member 98. The aperture 134 is large enough to permit unrestrained movement of the pin 135 when the pin 135 is shifted with the singleoperating member 98 between its two extreme positions, as will be described hereinbelow.

A pin 136 is secured on the face of the cam disk 94 to coact with a spring finger 137 secured to a microswitch 138. The pin 136 is positioned in a set relationship with the cam disk spot 121 so that when the pawl 115 abuts the spot 121 during the formation of the second half of the buttonhole, the pin 136 has been rotated into an abutting contact with the spring finger 137, thereby forcing the spring finger 137 against the pushbutton 139 of the microswitch 138 to trigger the microswitch 138.

Referring again to FIG. 5, when the machine power switch 140 is closed by moving the switch 140 to the ON position as shown in FIG. 1, an AC current flows from a convention source (not known) through the motor-controller assembly 141 and permits a current to flow through the sensing circuit of the buttonholing mechanism when a microswitch 142 is closed. Microswitch 142, as shown in FIGS. 1 and 10, is held open by the outer flange 102 of the pin 101 abutting its pushbutton and is activated by the buttonhole assembly handle 111 which determines the position of the pin 101. The microswitch 142 is closed when the handle 1 1 1 occupies the left-hand position as illustrated in the drawings, whereby the outer flange 102 has been moved out of abutment with the pushbutton by the handle 111. When the microswitch 142 is closed, the AC current flows through the stepdown transformer 143 from which a low voltage is supplied to the light source 77 and to the full wave bridge rectifier 144. The full wave bridge rectifier 144 supplies a DC current to the opto-electronic system 72.

When the photocell 79 is activated, the current from the opto-electronic system 72 flows through the resistors 145, through a Silicon controlled rectifier 146 hereinafter called an SCR, through the microswitch 138 positioned at point 150 and through the solenoid 132. The resistors control the amount of current flowing through the gate 147 of the SCR 146. A conventional resistor 148 and a conventional freewheeling diode rectifier 149 positioned across the load of the solenoid 132 were added to the circuit to permit proper operation of the solenoid 132.

When the solenoid 132 is activated by the opto-electronic system 72, the plunger 131 is retracted, thereby moving the pin 129 out of the pawl slot 130 to release the pawl 127. Even though the photocell 79 is no longer activated, the SCR 146 normally will continue to be energized, thereby maintaining the solenoid 132 in an activated condition. However, the full wave bridge rectifier 144 supplies a varying DC current to the SCR 146, where the current one pointis low enough to discharge the SCR 146, thereby causing the solenoid 132 to be deactivated, whereby the solenoid spring 133 forces the point 151, through the relay 152 which controls the latchingcontacts 153 and through a conventional resistor 154. The conventional resistor 154 and the conventional freewheeling diode rectifier 149, which is now positioned across the load of the relay 152, permit proper operation of the relay 152.

When the relay 152 is activated by the opto-electronic system 72, the latching contacts 153 are moved from a normally closed position at points 155, 156 to a normally opened position at points 157, 158. With the latching contacts 153 positioned at point 157, the circuit of the motor-controller assembly 141 is opened thereby cutting. power to the sewing machine motor 141 and stopping the sewing machine. At the same time, with the latching contacts 153 positioned at point r 158, the SCR 146 is short circuited and therefore is discharged so that the SCR 146 may be in readiness for the formation of the next buttonhole.

The power to the sewing machine motor 141 will remain off until the power to the relay 152 is interrupted. If the operator. does not desire to make any more buttonholes, the buttonholing assembly handle 111 may be moved to the right-hand position. This operation opens the microswitch 142 and'cuts the power to the relay 152 to return the latching contacts 153 to the normally closed position at points 157, 158, whereby the power to the motor 141 is restored so that the normal functions of the sewing machine may be preformed. If the operator 1 desires to make additional buttonholes, the operator turns the knob 96 to a start position indicated by the tab 97. This operation moves the pawl 115 off the spot 121 into engagement with the first tooth of the ratchet teeth group 119, and also moves the pin 136 out of contact with the spring finger- 137 to release the microswitch pushbutton 139. When the pushbutton 139 is released, the microswitch 138 returns to point 150, thereby cutting the power to the relay 152 to return the latching contacts 153 to the normally closed position-at points 157, 158, whereby the power to the motor 141 is restored so that the buttonholing functions of the sewing machine may be preformed.

With particular reference to FIGS. 6, 7, 8 and 9, the operation of the buttonholing mechanism of this invention in the sewing machine illustrated in the accompanying drawings will now be described. The material M on which the buttonhole is to be sewn is placed under the presser foot 36 with the O-ring 52 of the wheel assembly 32 resting on the material M. The wheel 50 is rotated by the operator until the reflective member 69 is directly underneath the end of the light guide I 73, as shown in FIG. 3, thereby establishing a reference point for starting and finishing the buttonhole. The tab 57 is rotated by the operator relative to the wheel 50 to set the reflective member 71 in a desired angular displacement from the reflective member 69 to determine the length of the buttonhole.

When the sewing machine controls are set for normal stitching operations, the handle 111 will occupy the righthand position, the pin 101 will be out of engagement with the aperture in the plate on the feed-regulating'member, and the outer flange 102 of the pin 101 will abut the pushbutton of the microswitch 142 to hold microswitch 142 in the open position. To produce a buttonhole using the buttonholing assembly 90, the handle 111 must first be shifted into the left-hand position, as illustrated in FIGS. 1 and 10, whereby the microswitch 142 is closed. As the pin 101 is not in alignment with the plate aperture, the leaf spring keeper lever 106 will yield and provide a biasing force urging the pin 106 against the plate. When the feed regulating handle 27 is shifted to bring the plate aperture into alignment with the pin 106, where the feed regulating handle 27 is positioned opposite the indicia '31 as shownin FIG. 1, the pin 106 will snap into an engaged position. The bight adjusting handle 26 is set at .the indicia 31, shown in FIG. 1, to obtain a bight of slightly less than halfthe capacity of the needle jogging mechanism. The control buttons:24 and 25 are also set with respect to the-indicia 31 so that as the width or bight of zigzagging is decreased to zero, the needle 20 will occupy a position on the right-hand side of the field of zigzag stitches.

To form the buttonhole, theknob 96 is turned to the start position, indicated by the tab 97 being opposite an indicia (not shown) on the escutcheon 30.-ln the start position, as shown in FIG. 12, the driving pawl is engaged in the first tooth notch of the ratchet teeth group 119, whereby the pawl 127 is held out of driving contact with'the disk cam 94 by the pin 135 being engaged in theaperture 134 and also by the pin 129 being engaged in the slot l30whereby the pawl 127 does not engage the ratchet'teeth group 119. In the starting position, the cam disk pin 136 does not engage the spring finger 137 which is secured to the microswitch 138.-

The closing of the machine power switch 140, by the operator, activates the light source 77. Because of the reflective member 69 in the start position is directly underneath the end of the light guide 73, as shown in FIG."3, the light carried by one-half of the light guide 73' from the light source 77 is picked up through reflection off the reflective member 69 by the other half of the light guide 73. The light is carried to the photocell 79, thereby activating the opto-electronic system 72 which inturn activates the solenoid 132 which retracts the pin 129' from the pawl slot-130.-However, the pawl 127 is not released, the pawl-127 being held by the pin 135 which is en} gaged in the pawl aperture. 134. As the beginning of the first round end of the buttonhole is being sewn by the sewing machine, the wheel 50 is being rotated by the linear motion'of the material M. Once the reflective member 69 is moved from its position underneath the light guide 73, the SCR 146 is discharged, thereby deactivating the solenoid 132 so that the solenoid spring 133 forces the pin 129 into its extended position, whereby, with the pawl 127 being in the held position, the pin 129 is engaged again in the pawl slot The ratchet teeth group-119 cooperates with the driving pawl 115 to index the cam disk 94 in a series of stepwise increments extending over a number of stitches so that the roller follower 99, shown in FIG. 11, will track the cam groove portion 132 and thereby shift the single-operating member 98 and the pin 135 secured thereon, from the upper to the lower extreme position. In the lower extreme position of the singleoperating member 98, the pawl 127 is held out of driving contact with the disk cam 94 only by the pin 129 being engaged in slot 130, as shown-in FIG. 13. The movement of the singleoperating member 98 from one extreme to another will carry the feed-regulating member gradually from a position of rearward work feed control through a position of zero feed of the work and into a position of forward feed of the work. Simultaneously, the needle 20 will be shifted from the position on the right-hand side to a position on the left-hand side of the field of zigzag stitches. This operation will produce the round end of the buttonhole, shown in FIG. 6.

At'the completion of the round end of the buttonhole, the reflective member 69 again isrpositioned directly underneath the end of the light guide 73, as shown in FIG. 3, so that the opto-electronic system 72 is activated, which in turn activates the'solenoid 132to retract the pin 129 from the pawl slot 130, thereby releasing the pawl 127. The spring 128 forces the pawl 127 into engagement with-the ratchet-teeth-group 119 while the pawl 115 continues to index the cam disk 94. The sewing machine remains in.the position of adjustment to produce a straight seam of zigzag stitches because the roller follower 99 tracks the cam groove portion 126 which has a constant radius.-

As the straight seam of zigzag stitches is being sewn, the wheel 50 continues to be rotated by the linear motion of the material M, so that the reflective member 69 is moved from its position underneath the light guide 73. Again the SCR 146 is discharged, thereby deactivating the solenoid 132 so that the solenoid spring 133 forces the pin 129 into its extended position against the pawl 127. As the bellcrank lever 113 imparts continuous motion to the pawl 127, the pawl 127 is raised and lowered by the ratchet teeth group 119. When the pawl 127 is in the raised position, the pin 129 is in alignment with the extreme right end of slot 130, as shown in FIG. and FIGS. 1217, so that the solenoid spring 133 again forces the pin 129 into the pawl slot 130. With the pin 129 engaged in the pawl slot 130, the pawl 127 still slightly engages the ratchet teeth group 119 but is held out of driving contact with the cam disk 94 so that the pawl 127 cannot index the disk cam 94.

When the pawl 115 thereafter in moving over the spot 122 of the cam disk 94 ceases to index the cam disk 94, as shown in FIG. 14, the sewing machine will still remain. in the position of adjustment to continue to produce the straight seam of zigzag stitches which constitutes one side of the buttonhole as illustrated in FIG. 7. During this time, the wheel 50 continues to be rotated by the linear motion of the material M, whereby the reflective member 71 on the tab 57 is being moved closer to the light guide 73.

When the reflective member 71 is rotated to a position directly underneath the end of the light guide 73, as shown in FIG. 4, the light carried by one-half of the light guide 73 from the light source 77 is picked up through reflection off the reflective member 71 by the other half of the light guide 73. The light is carried to the photocell 79, thereby activating the opto-electronic system 72 which in turn activates the solenoid 132 which retracts the pin 129 to release the pawl 127, in the manner stated above. The spring 128 forces the pawl 127 into a driving engagement with the ratchet teeth group 120, as shown in FIG. 15. The pawl 127 rotates the cam disk 94 so that the spot 122 is moved out of abutment with the pawl 115, whereby the ratchet teeth group 120 is brought into engagement with the pawl 1 15.

At first, both the pawls 115, 127 cooperate with the ratchet teeth group 120 to index the cam disk 94 to form the second round end (bottom) of the bottomhole, whereby the wheel 50 continues to be rotated by the linear motion ofthe material M. Once the reflective member 71 is moved from its position underneath the light guide 73, the SCR 146 is discharged, thereby deactivating the solenoid 132 so that the solenoid spring 133 forces the pin 129 into its extended position against the pawl 127. The solenoid spring 133 again forces the pin 129 into the pawl slot 130 when the continuously moving pawl 127 is raised by the ratchet teeth group 120, in the manner set forth above, so that the pawl 127 is held out of driving contact with the disk cam 94, whereby the pawl 127 still slightly engages the ratchet teeth group 120.

The pawl 115 continues to index the cam disk 94 in a series of steps extending over a number of stitches, during which time the cam groove portion 124 will shift the single-operating member 98 and the pin 135 secured thereon, from the lower extreme position toward the upper extremity of the range of positions. The pin 135, in the raised position within the pawl aperture 134, cooperates with the pin 129 to support the pawl 127 so that the pawl 127 is held out of driving contact with the disk cam 94, as shown in FIG. 16, whereby the pawl 127 does not engage the ratchet teeth group 120. The movement of the single-operating number 98 from the lower extreme to the upper extreme position will carry the feed-regulating member gradually from a position of forward work feed control through a position of zero feed of the work and into a position of rearward feed of work. Simultaneously, the needle will be shifted from the position on the left-hand side to a position on the right-hand side of the field of zigzag stitches. The opposite end of the buttonhole will be produced automatically during this second series of motions of the cam disk 94, as illustrated in FIG. 8.

At the completion of the bottom of the buttonhole, the reflective member 71 again is positioned directly underneath the end of the light guide 73, as shown in FIG. 4, so that the opto-electronic system 72 is activated, which in turn activates the solenoid 132 to retract the pin 129 from the pawl slot 130. However, the pawl 127 is not released, the pawl 127 being held by the pin 135 which is engaged in the pawl aperture 134. The pawl continues to index the cam disk 94-. The sewing machine remains in the position of adjustment to produce a second straight seam of zigzag stitches because the roller follower 99 tracks the cam groove portion which has a constant radius. As the second straight seam of zigzag stitches is being sewn, the wheel 50 continues to be rotated by the linear motion of the material M, so that the reflective member 71 is moved from its position underneath the light guide 73. Again the SCR 146 is discharged, thereby deactivating the solenoid 132 so that the solenoid spring 133 forces the pin 129 into its extended position, whereby with the pawl 127 being in the held position, the pin 129 is engaged again in the pawl slot 130.

When the pawl 115 thereafter in moving over the spot 121 of the cam disk 94 ceases to index the cam disk 94 as shown in FIG. 17, the cam disk pin 136 triggers the microswitch 138. The sewing machine still remains in the position of adjustment to feed the work in the reverse direction and continues to produce the second straight line of zigzag stitches comprising the opposite side of the buttonhole, whereby the sides of the buttonhole are parallel. During this time, the wheel 50 is still being rotated by the linear motion of the material M, whereby the reflective member 69 on the wheel hub 54 is being moved closer to the light guide 73.

When the reflective member 69 is rotated to a position directly underneath the end of the light guide 73, as shown in FIG. 3, the light carried by one-half of the light guide 73 from the light source 77 is picked up by the other half of the light guide 73, this time through reflection off the reflective member 69. The light is carried to the photocell 79, thereby activating the opto-electronic system 72 which in the-present circuit activates the relay 152 which moves the latching contacts 153 to the normally opened position at points 157, 158 to stop the sewing machine by cutting power to the motor 141 and also to discharge the SCR 146, in the manner stated above. At this point, the side stitching has reached the initially formed end of the buttonhole so that the buttonhole has been completed, as shown in FIG. 9. When the cam disk 94 is in the latter position, as shown in FIG. 17, the buttonholing assembly 90 will have no effect upon the needle jogging mechanism of the sewing machine and thus, if the buttonholing assembly 90 is decoupled from the feed regulating member by a shift of the handle 111 to the right to urge the pin 101 out of engagement with the plate aperture and also to open the microswitch 142 to restore power to the motor 141 as set forth above, the buttonholing assembly 90 will have no effect whatever on the entire range of the zigzagging capability of the needle nor upon the entire range of manually controllable positions of the work-feeding mechanism ofthe sewing machine.

Numerous alterations of the structure herein disclosed will suggest themselves to those skilled in the art. However, it is to be understood that the present disclosure relates to a preferred embodiment of my invention which is for purposes of illustrations only and not to be construed as a limitation of the invention.

Having thus set forth the nature of the invention, what I claim herein is:

1. In a zigzag sewing machine having an endwise reciprocatory needle bars, mechanism for jogging said needle bar laterally to produce zigzag stitches including a member regulating the neutral position of needle jogging motion, a workfeeding mechanism including a feed-regulating member having a range of positions corresponding to forward and reverse directions of work feed, and actuating mechanism in said sewing machine operatively connected to impart endwise reciprocatory and laterally vibratory movements to said needie bar and movements to said work-feeding mechanism in timed relation thereto, a buttonholing mechanism comprising rotary cam means supported on said sewing machine, a singleoperating member guided to move between extreme positions along a constrained path, a follower carried by said operating member in tracking relation with said rotary cam means, linkage in said sewing machine operatively connecting said member regulating the neutral position of needle jogging motion with said single-operating member in only one extreme position of said operating member, a manually separable connection between said single-operating member and said feedregulating member, drive means operated by said sewing machine actuating mechanism for imparting turning movement in stepwise increments to said rotary cam means in first and second spaced portions of said rotary cam means, said first and second spaced portions rotary means, and the intervals between said spaced portions defining the periphery of said rotary cam means, operator-influenced handle means secured to said rotary cam means for turning said rotary cam means through one interval so that said drive means engage said first portion, and means responsive to movement of the work for turning said rotary cam means through the other interval so that said drive means engage said second portion.

2. A buttonholing device according to claim 1 wherein said drive means comprises an oscillatory pawl operated by said sewing machine actuating mechanism, said rotary cam means comprising a cam disk having ratchet teeth on said first and second portions arranged almost all around the cam disk periphery and formed to accommodate stepwise engagement of said oscillating pawl, said intervals being two plain, diametrically opposed peripheral surface spots.

3. A buttonholing device according to claim 2 wherein said means responsive to movement of the work comprises a second oscillating pawl operated by said sewing machine actuating mechanism, releaseable means for holding said second pawl out of driving contact with said cam disk, an electrical circuit operating said releasable means, and means for providing sensing pulses at a preset position to said electrical circuit for controlling said releaseable means, whereby at said preset position said releaseable means release said second pawl so 7 through slot means formed in said second pawl, said slot means permitting continuous oscillating movement of said second pawl while said second pawl is being held off said cam disk by said pin, whereby at said one preset position said solenoid is activated to retract said plunger, thereby moving the pin out of the slot means to release said second pawl.

5. A buttonholing device according to claim 1 having second means responsive to movement of the work for stopping the sewing machine at the completion of the buttonhole comprising abutment means on said rotary cam means, said abutment means being turned to a predetermined position to control an electrical switch of a first electrical circuit, said electrical switch permitting said first electrical circuit to operate a relay, said relay controlling latching contacts of a second electrical circuit, said second circuit operating the sewing machine motor, and means for providing sensing pulses at the completion of the buttonhole to said first electrical circuit for activating said relay when said abutment means are in said predetermined position, whereby the activated relay moves said latching contacts to an opened position thereby opening said second electrical circuit to cut power to the sewing machine motor and stopping the sewing machine.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US3113537 *Nov 22, 1960Dec 10, 1963Necchi SpaMachine for sewing on designs including buttonholes
US3503350 *Nov 20, 1967Mar 31, 1970Singer CoSewing machine cam selector mechanisms
US3518954 *Jun 21, 1968Jul 7, 1970Singer CoRound end buttonhole mechanism for zigzag sewing machines
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4019449 *Oct 18, 1976Apr 26, 1977The Singer CompanyAutomatic buttonholing sizing device
US4056070 *Oct 15, 1976Nov 1, 1977The Singer CompanyAutomatic one-step buttonholing device
US4121526 *Sep 30, 1977Oct 24, 1978The Singer CompanyElectronically controlled sewing machine with cam controlled feed
US4182249 *May 24, 1978Jan 8, 1980Maruzen Sewing Machine Co., Ltd.Automatic buttonhole apparatus for use with sewing machine
US4191121 *May 23, 1977Mar 4, 1980Janome Sewing Machine Co. Ltd.Buttonhole stitch control system for a sewing machine
US4280424 *Dec 26, 1978Jul 28, 1981Necchi S.P.A.Household type sewing machine having microprocessor control
US4622910 *Jun 18, 1985Nov 18, 1986Otto HangarterButton hole sewing device
USRE32143 *Dec 6, 1982May 13, 1986Necchi S.P.A.Household type sewing machine having microprocessor control
DE2938064A1 *Sep 20, 1979Apr 2, 1981Kochs Adler AgNaehautomat mit steuerung durch einen rechner zur erzeugung einer bahnkurve
Classifications
U.S. Classification112/446, 112/449
International ClassificationD05B3/00, D05B3/06
Cooperative ClassificationD05B3/06
European ClassificationD05B3/06
Legal Events
DateCodeEventDescription
Jan 13, 1989ASAssignment
Owner name: SSMC INC., A CORP. OF DE, CONNECTICUT
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:SINGER COMPANY, THE;REEL/FRAME:005041/0077
Effective date: 19881202