US1151735A - Thread-cutting mechanism. - Google Patents

Description

1.]. SULLIVAN & A. F. FIFIELD.

THREAD CUTTING MECHANISM. 7

APPLICATION FILED NOV. 14. 1912.

Patented Aug. 31, 1915 a SHEETSSHEET 1.

EL N- 7850 WlT/VESSES: I EII/TOH- BY I l. l. SULLIVAN & A. F. FIFlELU.

THREAD CUTTING MECHANISM.

APPLICATION FILED NOV. 14, 19|2.

31 9 1L 5 1 735., Patented Aug. 31, 1915.

3 SHEET3SHEET 2 W/TA/ESSES: //V A/ B3 E4 2335 BY if e 1.]. SULLIVAN & A. F. FEHELD.

THREAD CUTTING MECHANISM.

APPLICATION FILED NOV. 14, 1912.

Patented Aug. 31, 1915.

3 SHEETSSHEET 3.

WITNESSES: fill/E/VTORS A q 9 M 'u afar JQHN J. SULLIVAN, G1 IPSWICH, MASSACHUSETTS, AND ALBERT E FIEIEL'D, {BF BRIDGElORT, CONNECTICUT, ASSIGNORS TO THE SINGER MANUFACTURING: CiJll L THREAD-CUTTING MECL'IANESM.

Specification of Letters Eatent.

ted

Patch Ang. 2331, 19

Application filed. November 14, 1M2. Serial No. 731,242.

- companying drawings.

While the present invention is adapted for application to various types of sewing machines, it is especially designed for embodiment in button sewing machines of the type shown in the United States patent to J. J. Sullivan and E. B. Allen No. 742,366, of October 27, 1903, and it has for one of its chief objects to simplify and to render more efiective the class of thread-cutting mechanism to which said patent is directed.

Certain other objects will appear in connection with the following description.

As preferably constructed, the cutting device is composed of overlappingthread-cutting and -nipping blades slidingly mounted within a transverse guideway of the presserfoot and whose extremity at the needle aperture affords shoulders coiiperating with the operative edges of such blades in the niping and severing actions upon the needlethread. Mounted upon a fixed fulcrum of the machine is a plural-armed lever having one arm connected by a link with the cutting and nipping blades and another arm operatively connected with the controlling cam for imparting lateral jogging movements to the needle and'controlling the period of action of the stitclrforming mechanism through the usual stop-motion device. By means of the controlling cam operative movements are imparted to said lever for retracting the blades from nipping and cutting or operative position into a position at the opposite side of the needle-path in readiness for a succeeding nipping and cutting action; and after the thread leading from the final stitch of a group has been loosely embraced by the blades. the action of automatic presser-foot lifting means thereon through a connection with a third arm of the plural-armed lever imparts to the nipping andcutting blades :1 quick operative movement while the needle is raised for nipping and cutting the thread.

'lhe nipping blade is preferably provided in its operative or nipping face with one or more indentations into which the thread is compressed between such face and the adjacent face of the guide-channel so as to form protruding parts of the partially crushed thread which look the same in position in addition to the frictional action of the parts between which it is thus clamped.

In the drawings, Figure 1 is a rear side elevation of a Singer button sewer embodying the present improvements, and Fig. 2 a front end view of the same. Fig. 3 is a perspective view of a portion of the stopmotion device, showing the operative connection between the same and the presserfoot lifting mechanism. Fig. i is a side elevation of the cutting mechanism and certain parts connected therewith, and Fig. 5 an end elevation of a portion of the cutter-actuating mechanism.- Fig. 6 is a perspective view of the presser-foot and the cutting elements positioned therein for a cutting action. Fig. 7 is an enlarged sectional elevation showing the action of the cutting device upon the thread. Figs. 8 and 9 are perspective views of the overlapping cutting and nipping blades taken respectively from the upper and lower sides. As represented herein, the frame of the machine comprises a hollow standard 1 with laterally extending work-supporting arm 2 and overhanging bracket-arm 3 in which is journaled the main-shaft 4 having upon its rear end the loose belt-pulley 5 and fast pulley 6 to which is attached the stopping cam 7 formed with the eccentric periphery 8 terminating in the notch 9. The head of the bracket-arm has mounted therein the laterally jogging needle-bar frame 10 and in which is journaled the needle-bar 11 carrying the needle 12 and connected by means of the pitman 13 with the crank-stud 14 upon the take-up cam-cylinder 15 secured upon the main-shaft l and from which the needle derives its reciprocating movements. The needle-bar frame is connected by means of the pitman 16 and other connections with the suitably grooved controlling cam 17 which imparts lateral jogging movements to the needle for production of fastening overseam stitches.

Within a suitable race 18 applied to tne work-supporting arm. 2 is mounted the shut tle l9 cooperating with the reciprocating and laterally jogging needle 12 and provided. with the usual bobbin-case 28 for the lower thread Mounted within the head of the bracketarm is the usual presser-bar :21 normally pressed downwardly by means of a spring 22 interposed between the lower end of the bushing 23 and. the collar 2% fixed thereon and provided with the lateral lug 25 and with ,a second forked. lug 26 embracing the guide-pin 27. Secured by means of the fastening screw 28 upon the lower end of the presser-bar is the shank 29 of the pressen foot 30 formed in its forward portion with the needle-slot or aperture 31 and at one side thereof with the lateral extension 32 which is shown provided in its lower face with the transverse guide-channel 33 closed in its lower side by means of the plate 34 secured thereto by screws 35 The presser-foot is shown cut away rearward of the needleaperture 31 to form the transverse buttonguiding seat 38 Mounted within the guide channel or guideway 33 is a compound cutting and nipping element comprising two overlapping blades 37 and 38 which are normally reversely arched, as represented in Figs. 8 and 9 and formed at the rearward end with alined apertures 39. At the opposite ends, these blades are provided with lateral hooked extensions a0 and ll'having operative shoulders 40 and ll upon the inner edges of the faces farthest apart. In practice, the edge 40' of the nipping member 4C0, which is arranged slightly in advance of the edge 4:1, is slightly rounded so as to avoid injuring the thread nipped between. the same and the correspondingly formed operative shoulder 32 of the channel 33, while the edge 41 is sharpened, as represented in Fig 7, so as to produce a shear-cut in conjunction with the opposed shoulder 34 of the channel 33. The nipping element 40 is shown provided in its upper or outer face with theniclrs or indentations 422 into which a portion of the needle-thread n is compressed; in the nippingoperation, as represented in Fig 7 to insure against pulling out of the cut end of thread leading to the needle in the production of the initial stitch of a group succeeding a nipping and cutting action,

The rearward ends of the blades 37 and 38 are secured by means of the clamp-screw 4-3 within a depressed seat forined therefor in thebloch which is providedwith the spaced and s 'iertured cars to between which is pivotally secured by means of the screw pin it one end of a "r 4:? whose apertured opposite end is connected by means of the screw-pin $8 with "he d pending arm 49 of an angle-lover hay has 50 and a eral arm 51 carrying t ie roller-stud 52., The hub 50 of the angle-lever ea Si. is secured by means of the set-screw 53 upon one end of the rocking pin 5d journaled in the bearing boss 55 of the bracket-arm 3 and having secured upon its opposite end by means of the set-screw 56 the hub 57' of an upwardly extending arm 58 carrying a roller-stud 59 which enters the cam-groove 60 of the cone trolling cam 17. The members 49 51 and '58 being rigidly connected together constitute a plural-armed lever fulcrunied upon the bearing boss 55w Mounted upon the fulcrum-stud 61 sustained by the bracket-arm 3 is the presserfoot lifting rock-lever comprising the forwardly extending arm 62 projecting beneath the lug 25 of the presser-barcollar 24 and the rearwardly extending arm 63 carrying the lateral stud-pin 64: which is embraced by the forked forward end 65 of the arm 66 of a rock-lever mounted upon the fixed fulcrum-stud 67 and having the rearwardly extending arm 68 provided with the laterally odset perforated boss 69. The boss 69 has fitted Within its socket the plunger-pin 78 whose reduced rearward end is provided with the thrust-nut 71 and jam-nut 72 to sustain the thrust of the spring 73 encircling the same and interposed between the inner end of the socket and the enlarged forward end of the pin.

The plunger-pin is adapted to engage the top and adjacent inclined side of the collar 74: fixed upon theplunger-bar 75 which is journaled in the rocking stop-lever 76' fulcrunied at 77 upon the bracket 78 su tained by the standard L interposed between the bearing boss 76' of the lever 76 and the collar 7% 1s a spring 79 which forces the upper end ofthe plunger-bar 75 into operative relation with the periphery of the stopping cam 7. The plunger-bar is normally maintained in operative relation with the stopping cam by means of a spring 80 interposed between the upper portion of the stop-lever 7G and the standard 1, and is shifted laterally in. opposition to such spring for disengagement of the plunger-bar and stopping earn by means of a lateral arm 81 of the stop-lever whose apertured outer end is entered by the headed upper extremity of the treadle-rod 82.

The arm 81 carries a laterally projecting stud 83 embraced by the forked extremity 84c of the lateral arm 85 of an angle-lever mounted upon the fulcrum screw-stud 86 and having the upwardly projecting arm 87 carrying a roller-stud 88 adapted to rest in contact with the end 88 of the controlling cam 17. The extremity 89 of the earn 17 affords a stop-shoulder to maintain the angle-lever 85 87 in position to hold the stoplever 78 retracted for continuing'the plunger-bar "Z5 disengaged from the stopping the controling cam 17, this notch a'iio a clearance recess which is J. 1 re o en red y the roller-stud under the action of the spring upon and through the stople er 76, t permitting the plunger-bar 75 unis to assume a position in register with the lower part of the perohery of the cam 7 and to be forced downwardly by the same until permitted to rise into the notch 9 under the action of the spring Y9,

The collar 74 is laterally retracted from 1 e plunger-pin 0 when the stop-lever is 'ted to the stopping elements nd throw the belt from the loose to the fast ul ey, but when the stop-lever returns to ping position, the collar 7 assumes operative relation wi h the plunger-pin T0 with its upper or operative face above the ere As the plunger descends under the tion of the peripheral portion of the cam t sin T0 is forced. inwardly by engagethe inclined adjacent side portion. collar until the top of the latter descends beneath it, when the pin snaps out above the same, and in the ascent of the plunger-bar 75 to enter the camnotch 9 the collar 74 forcibly engages the plunger-pin i0 and tilts the rock-lever (36 68 which produces a similar elfect upon the rock-lever 62 and lifts the Presser-bar and with it the presser-foot in opposition to the spring The tilting of the rock-lever arm 63 by the means just described causes the latters forcible engagement with the rollerstud 52 of the arm 51 which causes the final step of the operative movement of the nipping and cutting blades 3? and 38, a clearance portion (30 being formed in the cam-groove (30 to permit the slight lateral movement of the roller-stud 59 produced by the presser-foot lifting mechanism.

As represented in Figs. 1, 2 and 7, the mechanism is in stopping position just succeeding a nipping and cutting action at the completion of a button-fastening operation. Upon the actuation of the treadle-rod 82, the stop-lever 76 is rocked to start the machine, and the presserefoot lowered upon the throatplate through the disengagement of the collar 7 1- with the plungerpin 70, the treadlc-rod being maintained lowered until the notch 89' has moved out of register with the roller-stud 88 when the latter is permitted to rest against the stop-member 89 to maintain the stop-lever in running position for a complete stitching cycle. The nipping and cutting elements 40 and 41 are not disturbed until the completion of the first few stitches of the cycle, after which the action of the cam-groove 60 upon the roller-stud 59 causes the rocking of the operating lever 49 51 58 to shift the operative elements 40 and. s1 across the needle-path while the needle is raised between. stitches to direct the lead of the needle-thread inter mediate such elements and the adjacent end of the channel or guideway 33.

During the final rotation of the mainshaft in a stitching cycle, the portion 60" of the arm-groove 60 acts upon the rollerstud o9 impart a partial retractive move ment to the nipping and cutting elements so as to loosely embrace the needle-thread, as represented in Fig 6, presenting thereafter to the roller-stud widened. portion (30 across which it is shifted by a quick movement in the final nipping and cutting stage of the operation under the action of the pr sser-foot lifting mechanismcoinci dent with the arrest of the main-shaft by the stop-motion device. lit the end of the stitching operation, the take-up lever 91 is preferably in its highest position, so that there will be no strain upon the nipped needle-thread at the beginning of the initial stitch of the succeeding group. 7

l fe have not described herein the button. presenting means shown in the accompanying drawings, as they form the subject of a pending application filed simultaneously herewith.

lala 'ing thus set forth the nature of the invention, what we claim herein is 1. in a sewing machine, the combination with stitch-forming mechanism, and a worksupport, of a presser'foot, a thread-cutting device sustained thereby, a connection between the presser-foot and the thread-cutting device through which operative movement is imparted to the latter, a spring for lifting the presser-foot, and a cam for compressing said spring and controlling its action in lifting the presser-foot.

2. In a sewing machine, the combination with stitch-forming mechanism, and a work-support, of a presser-foot, a threadcutting device sustained thereby, lifting means for the presser-foot comprising a spring and a cam for compressing said spring and controlling its action in lifting the presser-foot, and an operative connection between the lifting means and the thread-cutting device whereby the movement of the lifting means is transmitted to the thread-cutter.

3. In a sewing machine, the combination with stitch-forming mechanism, and a worksupport, of a presser-foot formed with a transverse channel, a thread-cutting device comprising a blade slidingly mounted within said channel and having an operative portion movable across the range of action of the stitch-forming mechanism, presser foot lifting means comprising a spring and a cam for compressing said spring and controlling its action in lifting the presser-foot, and a connection between the presser-foot lifting means and said blade whereby movement of the lifting means is transmitted to the thread-cutter.

4. In a sewing machine, the combination with stitclrforming mechanism, and a work-support, of a presser-foot, a thread cutting device including a severing member, a controlling cam for determining the period of action of the stitch-forming mechanism, a connection between the controllingcam and the thread-cutting device for positioning the severing member preparatory to a cutting action, presser-foot lifting means, and a connection between said lifting means and the thread-cutting device for imparting to said severing member a second movement in the same direction to cut the thread.

5. In a sewing machine, the combination with stitch-forming mechanism, and a work-support, of a presser-foot formed with a transverse channel, a thread-cutting device comprising a blade slidingly mounted within said channel and having an operative portion movable across the range of action of the stitchiorming mechanism, a swinging operating lever, a link having pivotal connections with said blade and lever, presser-foot lifting means, and an operative connection between said lifting means and said lever.

6. In a sewing machine, the combination with stitch-forming mechanism, and a work-support, of a presser-foot formed with a transverse channel, a thread-cutting device comprising a blade slidingly mounted within said channel and having an operative portion movable across the range of action of the stitch-forming mechanism, presser-foot lifting means, a plural-armed operating lever having one arm connected with said blade, a second arm connected with and actuated by a cam, and a third arm operatively connected with the presser-foot lifting means.

7. In a sewing machine, the combination with stitch-forming mechanism, of a threadcutting device including a blade movable across the range of action of the stitchi'orming mechanism, a controlling cam, a connection between said controlling cam and said blade from which the latter derives successively a single retractive movement from operative position and a partial advance movement toward the same, and means timed in its action by a connection with said controlling cam for imparting to said blade a further advance movement into initial. operative position.

stop-motion device for completing the ad Vance of said knife to initial operative position.

9. In a sewing machine, the combination with stitch-forming mechanism, and a worksupport, of a presser-toot formed with a transverse channel, a thread-cutting and nipping element slidingly mounted within said channel and having an operative portion movable across the range of action of the stitch-forming mechanism and having one face formed with an indentation and adapted to act in conjunction with a wall of such channel in nipping the thread, and means for imparting operative movements to said blade.

10. In a sewing machine, the combination with stitch-forming mechanism including a reciprocating needle, and a work-clamping member, of a thread-cutting and nipping blade formed with a lateral extension movable across the needle-path and provided with thread-cutting and nipping edges, cut ting and nipping elements disposed permanently at one side of the needle-path for cooperation with the cutting and nipping edges of the extension of said blade, a support for said blade and the cooperating cutting and nipping elements sustained by and movable toward and from the work with said work-clamping member and provided with a guideway in which said blade is mounted for endwise rectilinear reciprocation, a rock-lever mounted upon a fixed fulcrum, a link connection between said rocklever and said blade for imparting rectilinear movements to the latter, and means acting at intervals comprising a plurality of stitch-forming cycles for imparting reciprocal operative movements to said bladerelatively to said cooperating thread-cutting and nipping elements.

11. In a sewing machine, the combination with stitch-forming mechanism, of a threadcutting and -nipping device including a longitudinally reciprocating blade formed with a lateral extension movable across the range of action of the stitch-forming mechanism and having thread-cutting and -nipping edges, a support provided with a guideway in which said blade is mounted for endwise rectilinear reciprocation, cutting and nipping elements disposed permanently at one side of the stitch-forming mechanism for cooperation with the cutting and nipping edges of the extension of said blade, actuating means for imparting to said blade its memes operative movements for action upon the names to this specification, in the presence of thrgad, and means actinfiindepemiiantlyl (if two subscribing witnesses. v sai actuating means wit in a perio inc u ing at least one complete stitch-forming P 6 cycle for imparting to said blade retractive movements from operative relation with the Witnesses:

relatively fixed. elements.- GEO. M EVANS,

In testimony whereof, we have siedl our STANLEY N. Smrrn.

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