US3357387A - Automatic thread cutting mechanism for button sewing machines - Google Patents

Description

Dec. 12, 1967 H. E. OWENS 3,357,387

AUTOMATIC THREAD CUTTING MECHANISM FOR BUTTON SEWING MACHINES ATTOR NE Y Dec. 12, 1967 H E. OWENS 3,357,387

AUTOMATlC I'HRAD CUTTING MECHANISM FOR BUTTON SEWING MACHINES Filed DeC. 22, 1965 2 Sheets-Sheet E 55k 57\ 5% IMM/A/ FIGB INVENTOR HORACE E, OWENS ATTORNEY United States Patent Otice 3,357,387 Patented Dec. 12, 1967 3,357,387 AUTOMATIC THREAD CUTTING MECHANISM FOR BUTTON SEWING MACHINES Horace E. Owens, Owings, S.C., assigner to Her Majesty Underwear Company, Mauldin, S.C., a corporation of South Carolina Filed'Dec. 22, 1965, Ser. No. 515,612 9` Claims. (Cl. 112252) This invention relates to a thread. cutting mechanism for sewing machines.

Themain objective of the invention is to provide a simplified, economical, automaticthread cutting attachment for a certain class fof butt-on sewing'machines which will cut the ythread cleanly upon completion of each button sewing cycle. The mechanism is particularly adaptable to a shank button .sewing machine designated Class 175-'62 in aninstruction booklet for Singer Sewing Machines, 1958 edition, by the Singer Manufacturing Company; The particular button sewing machine is entirely conventional and is well-known in the art.`

Another object ofthe invention is to provide an automatic thread cutting attachment for the above class of machine which takes advantage of the movement of the sewing machine stop motion for directly controlling the cycle of operation of the invention. This greatly simplifies the invention mechanism and renders it substantially foolproof in its timing and automatic cycle of operation and results in the minimum possible number of parts for the actual attachment.

Still. another object is to provide an automatic thread cutting attachment which is rugged and durable and which requires no alteration of the basic sewing machine structure or repositioning of its operating components and no interference with the button sewing cycle of operation.

Other objects and advantages of the invention will become apparent during'the course of the following detailed description.

In the accompanying drawings forming a part of this application and in which like numerals are employed to designate like parts throughout the same,

FIGURE 1 is a fragmentary plan view of a shank button sewing machine, partly in cross section, having the invention thread cutting mechanism mounted thereon in one operative position;

FIGURE 2 is a similar view showing the thread cutting mechanism in the active or cutting position;

FIGURE 3 is an enlarged fragmentary side elevational View of the thread cutting mechanism;

FIGURE 4 is an enlarged fragmentary end elevation, partly in section, of )the sewing machine and invention mechanism showing the relative position of parts at the completion of a button sewing cycle;

FIGURE 5 is a similar view of the same parts at the beginning of the button sewing cycle; and

FIGURE 6 is a fragmentary vertical section taken on line 6 -6 of FIGURE 2.

In the drawings, wherein for the purpose of illustration is shown a preferred embodiment of the invention, the numeral 10 designates generally a conventional shank button sewing machine of the type known in the art as a Singer Model No. 17562 machine. This machine includes a work surface or plate 11 over which the cloth, not shown, is positioned to have shank buttons 12 sewn thereonby the well-known zig-zag needle mechanism. The shank buttons are positioned on edge, as shown in FIGURE l, in a special anvil or support 13 for this purpose, also of a known, conventional construction.

The sewing machine has a main drive shaft 14 upon which is mounted a stop dog 15 which operates in conjunction'with a cushion spring holder 16 mounted on a machine rock shaft 17 and carrying. a stop dog cushioning spring 18 projecting therefrom asA shown inthe drawings. Tlie'elements16, 17 and 18, yalongwith the stop dog 15, are all conventionalparts. ofthe machine stop motion' which are cycled. andk operated automatically,

The automatic thread cutting mechanismv forming the direct subject matter. ofthe invention comprises, an, elongated bar 19 havinga longitudinal groove 20 in itstop face and serving as a fixed bedorfguide foratifr elongated carriage member 21 which` engages slidably within the` groove 20 and extends for its entire; length, The. bar 19 which forms the supporting body. portion of: the mechanism isA attached to one 'side of they machine based-.2 2A by, Vscrews 2.3- or` the ylike at spaced points. 'fhecarriage member-21- which is in effectA a slide includes. forward laterallyr enlarged head portion 24 integral therewithhaving shoulders 25 adapted to engage the forwardenclfof4 the bari'19fso as to positively limitl Ythe rearward` movementoftthe cfaririage member. The carriage member '21, is resilientlyfbialsed a retracted or inactive position, as shown FIGURE 1, by a carriage return springy 2%6fhavin'g its forwardfend, choredv at 27 to the carriage member! and its rear-endsimilarly anchored at 28 to a 'bracket 29 tixedlyl secured, at 3.0 to therear portion of. bar 19, In addition to anchoring the spring 2,6,v the. stationaryy bracket 2 9*V aids-V infretaining the carriage memberor slide 21 in thes liallovv grooveulll,y A further retainer plate is providedffor this] purpose on the `bar 19 near. the forward engll ofI the same. Thel bracket 29 also limits` the forward movement'ofcarriage member 21 by contact with an upstanding rigid 32 formed integrally on thel rear 'end' thereof. In"normal operation forI thread cutting, "the extent of "forward moveI ment of the carriage member l21, is such that the lugl 32 does not quite make contact with the bracke`t`2l9'. VNef/,ertheless, this bracket ywouldrestrict excessive forward movement of the carriage member.

The forward, head 24 is provided with al longitudinal slot 33, allowing the adjustable connectionn ofal horizontal extension arm 34 tothe carriage member 21, as 1indicated at 35. The extension arm 34 projects laterally of the carriage member and closely Aoverlies theV machine work surface 11. The extension arm. 34,is thus mounted. bodily upon the carriage member 21 and reciprocatestherewith.

A reciprocatory thread cuttingblade. or knife 3.6 operates slidably upon the anvil surface 13. beneath agrooved hold-down and guide element 37 xedly. securedfto the member 13. The leading end. 3.8 of;blade 36 is suitably beveled to form a thread cutting edge. The blade. is adapted to operate beneath the cloth, not shown, to cut olf the thread cleanly close to the buttonshankr 39 after the sewing operation is completed. The rear end` of blade 36 carries an upstanding pin 4t) which is receivedby a slot y4,1. in the extension arm 34 so. that the latter, may drive the blade36 smoothly.l andwithout binding. It will be understood that the elements 2,1, 34 and. 36`recipro.- cate as a unit and have rectilinear motion imparted thereto along the guide slot520.

Fixedly anchored withinan opening 4,2inrtherear end of bar 19 is a pin or` shaft 43held in place by a set screw 44 or thek like. The shaft,4 43 projects for a considerable distance beyond the rear end of the bar 19 and has adepending positioner arm 45 rigidly secured thereto as,by a set screw 4,6. The elements-@and t5-are therefore, both rigidwith the stationary bar 19,l

Between the pos'itionerv arrnk45.andtherearendof bar 19 a sleeve 47 is rotatablyy mounteduponthe shaft" 43, andthissleeve directly carries a plunger` guide 43, which may be integral therewith orl weldedthereto. Ther,lplunger guide 48 is on the top of sleeve 47,- asv'shown, and..y projects laterallybeyond. theinner side thereof. and across the-back of the machine. base22, FIGUREAQAbloclclike cam actuator 49 is arranged within a recessed portion of the plunger guide 48 and is pivoted thereto for horizontal turning movement thereon by a suitable pivot element 50 arranged near one corner of the cam actuator. As shown in FIGURES 1 and 2, the cam actuator 49 is square and when it is in the inactive position, FIG- URE l, one of its straight sides 51 abuts the edge of the recess in which the actuator is seated so that it will turn no further in the counter-clockwise direction, as viewed in FIGURE 1. The cam actuator 49 is resiliently biased to this inactive position by a return spring `52 having one of its Vends anchored to the cam actuator and its other' end similarly anchored to the plunger guide 48.

The kforward edge 53 of the cam actuator 49 which directly engages the lug 32 of carriage member 21 is normally spaced slightly therefrom while in the inactive position, as indicated at 54 in FIGURE 3. The cam actuator 49 is caused to turn to the active position in FIGURE 2 by a plunger 55 mounted slidably within a bore of the plunger guide 48 and having its leading end directly contacting the edge 51 of the cam actuator 49. The pin element 56, FIGURE 6, which serves to anchor the spring 52 to the guide 48, may also pass through a notch 57 formed in the plunger 55,l so as to limit positively the reciprocatory movement of the plunger upon the guide 48.

It may now be understood that the entire guide 48, plunger 55 and cam actuator `49 are all bodily mounted upon and turnable with the sleeve 47 upon the axis of shaft 43. The freely rotatably plunger guide 48 and associated elements rests freely upon and is supported by the cushion spring holder 16, as best shown in FIGURE 4, and this constitutes an important feature of the vinvention and its operation, to be further described. A diagonal positioner spring 58 interconnecting theguide 48 and the positioner arm 45, as shown at 59, serves to resiliently hold the guide in rm contact with the spring holder 16 at all times. When the spring holder 16 turns in either direction with the rocker shaft 17, the plunger guide 48 and associated elements will turn automatically therewith, and the spring 58 will maintain contact between the parts 4S and ,16, as shown.

The cycle of operation of the thread cutting mechanism above-described in conjunction with the sewing machine stop motion is as follows:`

When the sewing machine is engaged in a conventional manner to begin Ithe button sewing cycle, the machine stop dog cushioning spring holder 16 automatically rotates away from the revolving stop dog which turns with the main drive shaft 14. This ysituation is shown in FIGURE 5. When this occurs, the holder 16 will lift and carry the plunger -guide 48, plunger 55 and all associated parts away from the stop dog and out of its path of rotation during the sewing of the Button onto the cloth.

As the normal sewing cycle is completed, the cushion spring holder 16 will return automatically to its active machine stopping position shown in FIGURE 4 and this is conventional in the sewing machine. This allows the positioner spring 58 to` pull the plunger guide 48 down to the active approximately level position shown in FIG- URE 4. At this time, both the plunger 55 and the cushion spring 18 are in the path of movement of the rotating stop dogf15.

As the stop dog 15 moves into the stop position and sli-ghtly short thereof, it contacts plunger 55, FIGURE 4, causing the plunger to shift axially toward the cam actuator 49 and turning the cam actuator, as shown in FIGURE 2, to cause shifting of` the carriage member 21 and blade 36 to the thread severing position where the thread is cleanly severed close to the button shank.

'I'he plunger 55 absorbs the initial impact of stop dog 15 and actually aids in stopping the machine. However, continued slight'movemeut of the stop dog after engaging the plunger brings the stop dog into contact with the cushioning spring 18 and completes the stopping of the shaft 14 and the machine. Following this, the compressed spring 18 expands to its relaxed position and normal length pushing back the stop dog 15 slightly and allowing the cam actuator 49 to return to the inactive position in FIGURE l under influence of the spring 52. This also moves the plunger 5S to its retracted or inactive position. At this time, the carriage returny spring 26 automatically withdraws cutting blade 36 from Vthe thread and returns the blade, arm 34 and carriage member 21 to the fully retracted position, thus completing the sewing and thread cutting cycle and preconditioning the parts for the next cycle of operation, where the holder 16 again moves the guide 48 and associated elements clear of the path of movement of the dog 15, as the machine starts up.

It is now clear that a highly simplified positive acting automatic thread cutter has been provided on the shark button sewing machine which is operated directly by the machine stop motion in such a mannerthat the thread is cut at precisely the right time, namely, at the end of the cutitng cycle. Also, the mechanism in conjunction with the stop ymotion conditions itself automatically for each succeeding cycle of operation, as explained.

It is to be understood that the form of the invention herewith shown and described is to be taken as a preferred example of the same, and that various changes in the shape, size and arrangement of parts may be `resorted to, without departing from the spirit of the invention or scope of the subjoined claims.

I claim:

1. A thread cutting mechanism for u button sewing r machine of the class having a rotating stop dog and a coacting cushioning part movable cyclically into the path of travel of the stop dog and clear of such path of travel, said mechanism comprising a supporting body portion attachable to the body of the sewing machine, a thread cutter device movably engaging said body portion and shiftable thereon toward and away from threadcutting positions, and an actuator means for the thread cutter device movably mounted upon the supporting body portion and being engaged with and supported by said cushioning part and shiftable with such part cyclically into the path of travel of the stop dog so that the stop dog may directly engage said actuator means and operate said cutter device to cut the button sewing thread.

2. The invention as defined by claim 1, and wherein said cutter device is a reciprocating cutter on the supporting body portion and said actuator means comprises a member pivoted to the body portion and adapted to rest upon the cushioning part, a plunger having guided engagement with said member and adapted to be engaged directly by said dog, and a pivoted cam actuator carried by said member and movable bodily therewith and adapted to engage said reciprocating cutter.

3. A thread cutting mechanism for a button sewing machine of the class having a rotating machine stop dog and a coacting stop part which swings cyclically into the path of movement of the stop dog and clear of said path of movement, said mechanism comprising a guiding and supporting member adapted to be rigidly secured to one side of the sewing machine base, a reciprocatory slide on said member, resilient means biasing said slide to a retracted position, a thread cutter element carried by the slide and positioned for direct engagement with the thread to cut the thread when the slide is extended on said guiding and supporting member, a plunger guide body pivotally mounted upon one end of the guiding and supporting member and adapted to contact and. rest upon said coacting stop part and to swing therewith, resilient means connected with the plunger guide body and holding it in Contact with the coacting stop part, a reciprocatory plunger on said guide body and adapted to direct- 1y engage said stop dog when in the path of movement thereof, a pivoted actuator part on the guide body and shiftable by said plunger against said slide to move the same in a thread cutting direction, and resilient means connected with said actuator part and urging the same toward an inactive position with said plunger.

4. The invention as dened by claim 3, and wherein said guiding and supporting member is an elongated bar having a longitudinal groove, said slide engaging within said groove and extending longitudinally therethrough, a lateral extension arm on the forward end of said slide, and said thread cutter element offset from said slide and connected with said extension arm.

5. The invention as defined by claim 3, and a shaft extension on the rear end of the guiding and supporting member, a sleeve rotatably mounted on the shaft eX- tension and bodily carrying said plunger guide body, a depending member on the shaft extension, and a retractile spring interconnecting the depending member and said plunger guide body to hold the same in contact with said coacting stop part and allowing the plunger guide body to swing with the coacting stop part.

6. The invention as defined by claim 3, and wherein said pivoted actuator part is a block-like element on the top of the plunger guide body, said guide body having a recess receiving said actuator part, and a lug on said reciprocatory slide positioned for engagement with one edge of the actuator part when the same is turned by said plunger.

7. In a button sewing machine of the class having a rotating stop dog and a coacting pivoted stop part which swings cyclically into the path of movement of the' stop dog and clear of said path, the combination with said coacting stop part of a pivoted guide device on said machine resting upon and supported by the coacting stop part, resilient means holding the guide device in contact with the coacting stop part, movable actuator means on said guide device adapted to be operated by thev stop dog when said coacting stop part swings into the path of movement `of the stop dog, and movable thread cutter means on said machine operated by said actuator means in response to operation thereof by the stop dog immediately prior to the stopping of the machine by engagement of the stop dog with the coacting stop part.

8. The invention as dened by claim 7, and wherein the coacting stop part includes a cushioning spring for the stop dog and said actuator means includes a plunger extending slightly in advance of the cushioning spring to engage with the stop dog prior to engagement of the dog with said spring.

9. The invention as defined by claim 7, and a common support member on said machine for the thread cutter means and pivoted guide device.

References Cited UNITED STATES PATENTS 1,841,102 1/1932 Field 112-252 2,509,619 5/1950 Vollman 112-252 3,267,892 8/1966 Maschmann et al. 112--252 X PATRICK D. LAWSON, Primary Examiner.

I. R. BOLER, Assistant Examiner.

Claims (1)

1. A THREAD CUTTING MECHANISM FOR A BUTTON SEWING MACHINE OF THE CLASS HAVING A ROTATING STOP DOG AND A COACTING CUSHIONING PART MOVABLE CYCLICALLY INTO THE PATH OF TRAVEL OF THE STOP DOG AND CLEAR OF SUCH PATH OF TRAVEL SAID MECHANISM COMPRISING A SUPPORTING BODY PORTION ATTACHABLE TO THE BODY OF THE SEWING MACHINE, A THREAD CUTTER DEVICE MOVABLY ENGAGING SAID BODY PORTION AND SHIFTABLE THEREON TOWARD AND AWAY FROM THREAD CUTTING POSTIONS, AND AN ACUTATOR MEANS FOR THE THREAD CUTTER DEVICE MOVABLY MOUNTED UPON THE SUPPORTING BODY PORTION AND BEING ENGAGED WITH AND SUPPORTED BY SAID CUSHIONING PART AND SHIFTABLE WITH SUCH PART CYCLICALLY INTO THE PATH OF TRAVEL OF THE STOP DOG SO THAT THE STOP DOG MAY DIRECTLY ENGAGE SAID ACTUATOR MEANS AND OPERATE SAID CUTTER DEVICE TO CUT THE BUTTON SEWING THREAD.

Images