US1705044A

US1705044A - Thread trimmer for buttonhole-sewing machines

Info

Publication number: US1705044A
Application number: US112810A
Authority: US
Inventors: Axel F Carlson
Original assignee: Reece Button Hole Machine Co
Current assignee: Reece Button Hole Machine Co
Priority date: 1926-06-01
Filing date: 1926-06-01
Publication date: 1929-03-12
Anticipated expiration: 1946-03-12

Description

March 12, 1929. A. F. CARLSON THREAD TRIMMER FOR BUTTONHOLE SEWING MACHINES Original Filed June 1, 1926 8 Sheets-Sheet 1 s n m r O A m e m ,x v a m n w F II a p p m m wiwfiw m B a E m u.. 5i 3 A .0 QB H w March 12, 1929. A. F. CARLSON 1,705,0

THREAD TRIMMER FOR BUTTONHOLE SEWING MACHINES Original Filed Juhe 1. 1926 8 Sheets-Sheet 2 Fig.2. 68 69 3 E lnvenfor. Axel FtCurlson yMWkf An s March 12, 1929. A. F. CARLSON THREAD TRIMMER FOR BUTTONHOLE SEWING MACHINES Original Filed Junel, 1926 8 Sheets-Sheet 3 3 8 w r. 0 mm Wm W 2 3 q New m Cl Jm M .w 6 mm 8 E I mm mm Ma Q WN 0 I r -2: mm mg 9 mm Nm a mm. .m @N 3 Anys.

March 12, 1929.

A. F. CARLSON THREAD TRIMMER FOR BUTTONHOLE SEWING MACHINES Original Filed June 1926 8 heets-Sheet 4 InvenTor. Axel F Carlson byMMAW.

ATTys.

March 12, 1929. A. F. CARLSON THREAD TRIMMER FOR BUTTONHOLE SEWING MACHINES Original Filed June 1, 1926 8 heets-sheet 5 lnvenTor.

Axel FTCorlson WM WkW ATTys.

March 12, 1929. A. F. CARL$ON 1,705,044

THREAD TRIMMER FOR BUTTONHOLE SEWING MACHINES Original Filed June 1, 1926 8 Sheets-Sheet 6 Fig.6.

i i ,4 f V :77

lnvenTor.

Axel F Carlson kfw - ATTys.

March 12, 1929. c sofl 1,705,044 I THREAD TRIMMER FOR BUTTONHOLE SEWING MACHINES Original Filed June 1, 1926 8 Sheets-Sheet 7 InvenTor. Axel F. Carlson bygemolwkfwaMj ATTyS.

March 12, 1929. A. F. CARLSON THREAD TRIMMER FOR BUTTONHOLE SEWING MACHINES 8 heets-Sheet 8 Original Filed June 1, 1926 lnvenTor. Axel F Carlson yfaw Mam Patented Mar. 12, 1929.

UNITED STATES PATENT OFFICE.

AXEL F. CARLSON, OF CAMBRIDGE, MASSACHUSETTS, ASSIGNOR TO THE REECE BUT- TON HOLE MACHINE COMPANY, OF BOSTON, MASSACHUSETTS, A CORPORATION OF MAIN E.

THREAD TRIMMER FOR BUTTONHOLE'SEWING MACHINES.

Application filed June 1, 1926, Serial No. 112,810. Renewed June 8, 1928.

This invent on relates to sewing machines and particuhirly to means for trimming the thread at the end of the sewing operation. The invention is herein illustrated as embodied in a sewing machine of the type shown in my co-pending application Serial No. 79.5233. filed January 6th. 1926.

in the device herein illustrated the tread trimmers are actuated at the end of each sewing operation by power mechanism which is normally idle but which is set in operation by the action of the stopping mechanism in bringing the sewing inslrumentalities to rest. The trimming mechanism is of that known type which is constructed to trim the thread twice for each sewing operation. once at the completion of the sewing operation in order to cut the thread leading to the source of supply and again at the beginning ot' the. next sewing operation.

Another feature of my invention relates to a novel trimmer adapted for these two trimming operations. which trimmer is formed with two oppositely-disposed cutting edges, one of which is active in trimming the thread at the end of the scam and the other of which is active in trimming the thread at the beginning of the seam.

The device also includes a. novel pull-ofi' me hanism for pulling otl' both the upper end th" under thread at the end of the sewing operation and for holding each thread end during the time that the machine is at rest and until the next sewing operation is begun.

The invention further includes various novel features and constructions. all as will he more t'ull hereina'iter set forth.

in order to give an understanding of the invention l have illustrated in the drawings a scicctevi embodiment thereof which will. now he dcscrihed after which the novel featin-cs will be pointed out in the appended claims.

Fig. l is a. side view of a sewing machine havin the improveincnts applied thereto;

Fig. Q. is a plan. view of the work-supporting arm and work clamps thereon together with the means for trimmingtlu upper thread and h lding the trimmed nd;

ig. 3 is a side view of Fig. 2;

Fig. T is a sectional view on substantially the line it 4?. Fig. l, iliustjating the poweracluating mechanism for operating the thread cutter;

Fig. 5 is a section on substantially the line 55, Fig. 4;

Fig. 6 is a fragmentary view illustrating the devices for controlling the driving clutch;

Figs. 7 and 8 tragmentary views showing part of the power-actuated mechanism for operating the upper thread holder;

Figs. 9 and 10 are fragmentary views showing the power-actnatcd means for operating the upper thread cutter;

Figs. 11 and 12 are fragmentary views illustrating the operation of the upper thread holder and cutter;

Fig. 13 is a fragm ntary view illustrating the mechanism for actuating the under thread trimmer and holder;

Fig. 14- is an enlarged fragmentary perspective view of the under thread pull-ofi' de vice;

Fig. 15 is a view illustrating the under thread cutter;

Fig. 16 is a view illustratim the under thread pull-off.

Fig. 17 is a section on the line 17-47, Fig. 3.

As stated above the present invent-ion is shown as emhodied in a sewing machine which is similar to that illustrated in my copcnding application Serial No. 79 5323, filed January 6th, 1926. said. machine being a two thread buttonhole sewing machine. The sewing machine has the frame 1 from which ex tends the usual overhanging arm 2 carrying the upper thread-manipulating mechanism and from which also extends a lower horizontal work-sup )orting arm 3 on which the work in is supported. The upper thread-manipulating mechanism comprises the usual needie 4 which is carried 1 a vertically-reciprocating needle bar 5. and the. under threadmanipulating mechanism, which is not shown herein. ma v he in the form of the usual oscillatory hook which takes loops of needle thread and casts them about a shuttle in a well-knownv way.

The operating mechanism is driven from a driving shaft 6 which in turn is actuated from a constantly-rotating driving pulley 7, the latter being driven by the driving belt 8. This driving pulley 7 is connected to and disconnected from the driving shaft 6 through the medium of a. suitable clutch, (not shown) situated in a recess in the pulley '7, said clutch being controlled by a cone-shaped clutch actuator 9 which is slidably mounted on the shaft (5, movement of the clutch actuator toward the left Figs. 4 and 6 throwing the clutch into engagement and movement to the right into the position shown in Figs. 4 and 6 releasing the clutch.

The clutch actuator 9 is controlled by a clutch-controlling rod 10 which is slidably mounted in the frame. said rod having fest thereon a forked arm ll, the fork of which engages in a groove 12 in the clutch-controlling member 9 so that movement of the rod 10 in the direction of its length will throw the clutch into engagement or release the clutch. The clutch-actuating rod 10 is given its clutch-engaging movement by means of an elbow lever 13 pivoted to the frame at 14, the vertical arm 15 of said elb v lever engaging the end of the rod 10. \Vhen the horizontal arm 13 is pulled downwardly the clutch-controlling rod 10 will be shifted to the left 4 and 6 thereby throwing the clutch into engagement and setting the machine in opera tion.

A suitable latch device is provided for automatically engaging the rod 10 when the clutch has been thrown into engagement, which latch device locks said rod in its operative position and maintains the clutch in engagement. This latch is automatically released at the end of the buttonhole and when so released the rod 10 will be retracted into its inoperative position by means of a suitable spring 16. The latch for locking the rod 10 in its operative position is indicated at 17 and it is adapted to engage automatically in a notch 118 formed in the rod 10 when the latter has been thrown into its operative position. The latch is released automaticallv by suitable mechanism. all as shown in my above-mentioned a 'ipliration.

The elbow lever 13 may be operated in any suitable way. It herein shown as having a link 18 )ivoted to the horizontal arm. which link is a apted to be actuated by a treadle or other startii'ig mechanism. The link is shown as extending through a head 19 fast on the end of a connection :20 that leads to a tread le or other starting device. said link having a collar 21 thereon so that when the connection 20 is moved downwardly and the head 19 is brought against the collar 2t the elbow lever 13 will be actuated to throw the clutch. Said elbow lever has a sprin connected thereto which tends to return it to its initial position shown in Fig. 4.

Associated with the starting mechanism above described is a stop mechanism by which the machine is brought to rest at the end of the stitching operation. This stop mechanism is similar to that shown in my above-nientioned application Serial No. 79,523. and it comprises a stop motion block 88 which is rigidly mounted on the clutch-controlling rod 10 and which yieldingly carries a stop dog 89 that co-operates with a stop cam 90 in bringing the machine to rest This stop cam 90 is fast on the shaft 6. When the clutch-controlli11g rod 10 is shifted to the left Figs. 4 and b to throw the clutch into engagement the stop motion block 88 and stop dog 89 are -arried to one side of the path of movement of the stop cam 90.

When the latch 17 is released at the end of the stitching operation and the clutch-controlling rod 10 is shifted to the right into the position shown in Figs. 4 and 6 thereby releasing the driving clutch the stop dog 89 will be carried into the path of movement of the stop cam 90 and during the rotation of the shaft said stop cam will engage the stop dog thus bringing the driving sha ft (3 to rest.

The work 20 is held by a suitable work holder comprising under clamps 23 and upper clamps 24. Both clamps are mounted on a work-supporting plate 25 which in turn is supported on the arm 3 so that it can move longitudinally of the arm and also transversely thereof. The movement longitudinally of the arm is that which gives the work its feeding movement during the stitching along the side of the buttonhole and the movement transversely of the arm is that which gives the work a jogging movement for forming the barring stitches at the end of the buttonhole all as usual in buttonhole sewing machines of this type. The means for giving the work holder its movement may be all as shown in my above-mentioned co-pending application Serial No. 79.523. and as it forms no part of my present invention I have not deemed it necessary to illustrate it herein.

The upper work clamps 24 are carried by arms 26 which extend from the upper end of a rocking member 27 that is pivoted on a shaft 28 carried by the clamp plate 25. These upper work clamps are yieldingly held against the work by means of springs 29 and at the end of each buttonhole they are raised and held raised by means of a latch 30 which engages a projection on an elbow lever 31 pivoted at 32, the horizontal arm 33 of said elbow lever engaging the under side of the arms 26 thus holding them raised.

When the machine is started the latch is automatically released thus allowing the clamps to close and this is accomplished by a lever 34 pivoted to the bed at 35 and having a roll 36 adapted to engage a cam face 3? on the under side of the latch. The lever 34 is connected by a link 38 with an elbow lever 39 which is pivotedto the frame and which has a link 40 connected thereto which extends through the head 19. said link 40 having a collar 41 thereon. The collar 41 is slightly above the collar 21 and hence when the eonnection 20 is moved downwardly the initial downward movement will act through the

connections

40, 39, 38 and 34 to raise the latch 30 and release the work clamps and continued downward movement will then throw the clutch into engagement and start the mechanism. The spring 42 acting on the lever 34 tends to return it to its normal position.

The work clamp and means for controlling it are or may be all as set forth in my copending application Serial No. 79.52;, or my (o-pending application Serial No. 112.507 tiled May 29, 1926.

As stated above the present invention rclates to a novel means tor cutting the needle thread at the end of the sewing operation and holding the severed end until after the next stitching operation has been begun and then cutting the held end directly after the second stitching operation has been begun, and also novel means for trimming the under three d and holding the severed end, the thread trimmers and the thread holders being actuat by power mechanism which is normally in active during the stitching on the buttonhole but which is thrown into operation by the stopping mechanism when the stitching on the buttonhole has been con'ipleted.

The upper thread trimmer is a blade 43 having the two oppositely disposed cutting

edges

44, 45. This cutting blade operates in a transverse slot formed in one of the work clamps and is carried by a shank 46 which in turn is secured to the end of an arm 47 that is pivoted at 48 to one of the upper work-clamping arms 26. The cutter-carrying arm 47 is provided with a lateral extension 49 which is acted upon by a spring 50 that normally tends to hold the cutter relative to the work clamps in the position shown in Figs. ll and 12, in which position it is at one side of the line of sewing. The trimming of the thread at the end of the seam is accomplished by a transverse movement of the blade into the position shown in Fig. 2 resulting from a swinging movement of the arm 47. as will presently be described.

Associated with the upper thread cutter is a thread holder which seizes the. needle thread between the needle and the work and holds or grips said thread while it is being cut and also maintains a hold on the thread until the next sewing operation has begun as usual in devices of this type. This thread holder is indicated at 51 and it is in the form of a hook carried by a swinging arm also pivoted to the clamp-carrying arm 26 at 48. The arm 52 is acted on by a spring F3 which tends nor-- mally to move said thread holder from the position shown in Fig. 2 to that shown in Fig. 12.

This thread holder lies in contact with the upper surface of one of the work clamps and is adapted to grip the needle thread between itself and said work clamp.

During the stitching on the buttonhole the upper thread holder and cutter occupy the po sition shown in full lines Fig. 12. \V hen the stitch-forming mcchanisn'l has come to rest the thread holder is moved from the full line position shown in Fig. 12 back to the full line position Fig. ll during which movement the thread holder engages the needle thread I, pulls otl a length thereotand clamps it against. the upper face of one of the work clamps. Alter this has been done the cutter is moved into the position shown in Fig. 2 across the line of stitching and the edge 44 of the cutter will actto cut the needle thread t between the thread holder and the work, the severed end of the thrc: l leading to the needle being retained by the thread holder.

The thread holder 51 and thread cutter 43 are normally held by their

springs

53 and 50 in the position shown in Fig. 12 and the operati ve movement of these parts into the position shown in Fig. which is the movement by which t upper thread is gripped and cut. is derived from power.ictuated mechanism which is ormally idle during the sewing of the buttonhole. but which is rendered operative by the action of the stop motion in bringing the machine to rest. Such poweractoatcd liltilltt'lllslll comprises a cam 54 mounted on a stud $3.3 carried by the frame. This cam is normally idle during the stitching on the buttonhole but at the end of the stitching it is connected to a constantly rotating member 56 through the medium of a onc revolution clutch so that the cam will make one revolution and then come to rest. During this one revolution the cam actuatcs a mechanism iich moves the thread holder 51 and the thread cutter 4Z3 positively into the )siti n1 shown in Fig. in which position thev are latched as will be presently described.

The c ntinually rotating member 56 is in the form of a gear member loosely mounted on the stud 55 and meshing with a. g ar 57 rigid with the driving pulley 7 so that the gear Fill will be rotating whenever the pulle is rotating.

The clutch by which lh the gear 56 similar to that shown in my copending application to ial No. and also similar to that shown in the application of John Kicwic'z. Serial ffo. 115th. tiled December 15th. 1925. This clutch comprises a clutch pin 58 carried by the cam l and acted on by a spring 59 which tends normally to throw the clutch pin into clutching engagemcnt with the coustautly-rotating member 56. Said clutch pin is noru'ially held disengaged by means of a clutch dog (it). This clutch dog is in the town ot an arm carried by a rock shaft (31 and when the shaft is turned anti-clockwivc l ig. l the clutch dog will be raised out of or agcmcnt with the herd of the clutch pin on and the latter will tch the cam to the constantly-rotatin55 member. said clutch pin being retracted again by the clutch dog when the cam has e cam is clutched to made one revolution as usual in one-revolution clutches.

its stated above this clutch is actuated by the stop motion. he shaft 61 has fast thereon an arm (32 carrying an adjusting screw 63 which is adapted to be engaged by an arm (it fast to the stop motion block 88. When the stop motion operates to bring the shaft 6 to rest as above described the engagement of the cam so with the stop dog 89 will give the stop motion bloc 88 a slight clockwise movement (see Fig. 5) thus carrying the arm 64 into the dotted line position, in which position it will engage the stop screw 63 and give the shaft 61 the requisite turning movement to release the dog from the clutch pin, thus allowing the clutch to become operative to clutch the cam 54 to the constantly-rotating member 56. The movement of the arm 64 into the dotted line position is momentary only and, therefore. as soon as the clutch pin has been released the clutch dog will return to its normal position shown in Fig. 1 ready to effect a disengagement of the clutch pin upon the completion of the rotation.

The cam 51 operates a lever 65 fast on a rock shaft (it; and said rock shaft. has fast thereon another arm 67 which is connected by a link (38 to a slide 69 that is slidably mounted on the bed of the machine. The cam 54 gives the slide (39 a positive movement to the left 3) and such movement gives rocking movement to a rocking actuating member 70 hit-h pivoted to the bed at 71. This member It) has a stud 72 extending therefrom on which is mounted a roll 73 and the slide 69 is provided with an inclined or am face 74: t is adapted to engage the roll 73 when the le is moved to the left Fig. 3. The engagement of the cam face 74 with the roll during such movement of the slide will rock the member 70 toward the left Fig. 3 about its pivot 71. and such rocking movement will first operate the thread holder 51 to cause it i the needle thread, as shown in Fig. 17, l than ca use the cutter to move into the po ition iown in Fig. 2 and dotted line po- .lil l 17. thereby cutting the thread be- .en the thread holder and the work. The tin-mid h liter arm 52 is provided with a lateral extension 75 which is connected by a link To to a rocking member 77 pivoted at 78 to the member 27 that carries the upper work clamps.

The power-ac uated member 70 carries a roll 79 which is a apted to engage the end face 80 of the rocking member 77 as shown in Fig. 7. The engagement of the roll 79 with the face 89 is at a point below the pivot 78 and hence as the member 70 swings toward the left Fig. 7 from the full to the dotted line position the engagement of the roll 79 with the face 80 will swing the member 77 into the position shown in Fig. 8 thereby drawing backwardly on the connection 76 and positive ly swinging the thread holder into the position shown in Fig. 2 againstthe action of the spring 53. This movement of the member 77 and thread holder occurs during the initial forward swinging movei'nent of the member 70 d no to the action of the slide 69. The member 77 is so constructed that after the swinging member 70 has reached the dotted line position Fig. 7 and has thus actuated the thread holder the roll 79 will pass onto the surface 179 which is at that time concentric with the pivotal axis 71 so that during further movement of the member 70 the roll simply moves forwardly on the surface 179 and thus holds the member 77 in the position shown in Fig. 8 while the thread cutter is given its threadcutting movement.

The lateral extension 49 of the thread-cutter carrying arm 47 is connected by a link 83 to a swinging member 8-1 also pivoted on the pin 78 (to-axially with the member 77. The stud 7 2 carried by the power-actuated member 70 has secured thereon a pusher or thrust member which is adapted to engage the swinging member 81- at a point below its pivotal point 78. as shown in Fig. 9, and hence the swinging movement of the power-actuated member 70 will operate to swing the member 8a into the position shown in Fig. 10 and through the connection 83 give the cutter its thread-cutting movei'nent, that is, movement from the full to dotted line position Fig. 17 or from a position shown in Fig. 11 to that shown in Fig. 2.

The construction is such that as the member 70 swings forwardly the roll 79 will act on the member 77 before the pusher 85 acts on the member 84. Hence during the initial swinging movement of the member 70 from the full to the dotted line position Fig. 7 the roll 79 will act on the member 77. as shown in Figs. 7 and 8, thereby actuating the thread holder and during the further swii'iging movement of the member 70 the pusher 85 will operate the swinging member 84 and thus give the thread cutter its thread-cutting movement. During this further swinging movement the roll 79 merely follows over the concentric face 179 and thus holds the member 77 in the position shown in Fig. 8.

\Vhen the member 70 has completed its forward movement and has swung the member 84 into the position shown in Fig. 10 both swinging

members

77 and 84 will be automatically latched by a latch 81 which is pivotally mounted on the pivotal rod 28 and is adapted to engage teeth or

shoulders

82 and 86 formed on the

members

77 and 84 respectively. This latch is counterweighted as shown at 87 so that it automatically clicks over

teeth

82 and 86 the

members

77 and 8 1 are operated.

With this construction. therefore. as the cam 54 makes its single rotation at the end of the sewing operation the thread holder will first be given a positive movement by said cam from the position shown in Fig. 12 to that shown in Fig. 2 thereby gripping the needle thread and subsequently the cutter will be moved from the position shown in Fig. 12 to that shown in Fig. :2 thereby to cut the needle thread between the thread holder and the work and after the thread holder and cutter have been moved into these positions they are automatically retained in such positions by the latch 81.

\Vhen the stitching on the next buttonhole is started the end of the needle thread is still retained by the holder 51 and after the stitching has progressed to a certain point the thread cutter is released from the latch 81 and is allowed to swing into the position shown in Fig. 11 under the influence of its spring 50. During this movement the cutting edge 45 engages the end of the needle thread which is retained in the holder and trims it close to the work. 'lhereafter the thread holder 51 is released from the restraining influence of the latch 81 and is allowed to move into the position shown in Fig. 12 u nder the influence of its spring 53. The cutter and thread holder are then set in position ready for the operation of seizing and holding the thread at the end of the buttonhole and then cutting the thread. This releasing movement of the latch is accom plished through the medium of a cam projection 88 adjustably secured to the bed and with which the tail or end 8'? of the latch engages during the feeding movement of the work. As the tail 87 rides up the inclined cam face 88 it will turn the latch as will be readily understood thus withdrawing it from the

shoulders

86, 82.

In order that the cutter may be first released to cut the thread while it is still held by the holder the point of the tooth 86 is situated slightly above the point of the tooth 82 so that as the latch is swung downwardly by the weighted tail 87 riding over the pro ection 88 said latch will be withdrawn from the shoulder or tooth 86 thus releasing the thread cutter before said latch is withdrawn from the shoulder or tooth 82. This will give a proper sequence of operations in the release of the thread cutter and thread holder.

The machine herein shown is also provided with means for pulling off a length of under thread at the end of each sewing operation and then cutting the under thread close to and beneath the work. This under thread pull-off and cutter is also actuated from the rock shaft 66. The under thread pull-off is in the form of a resilient arm 91 (see Fig. 16) which is carried by a rocking member 92 pivoted at 93 to the under side of the bed frame. This rocking member has a fork a; which embraces a stud 95 carried by a slide 96 which operates beneath the bed frame. The rear end of the slide is provided with an opening 97 in which is received the lower end of a lever 98 that is pivoted to the frame at 99,

the upper end of said lever having a slot 100 therein in which is received a pin 101 carried by the lever arm 67. When, therefore, the rock shaft 66 is turned by the cam 54 thereby to operate the upper thread cutter, the corresponding movement of the arm 67 will operate through the lever 98 to force the slide 96 rearwardly. Such rearward movement will saving the member 02 and the pull-01f arm 91 into the dotted line position Fig. 16 thus carrying the pull-oii' arm across the sewing opening 102 and engaging the under thread thereby pulling oil a length of the latter.

This pull-otf arm 01 is constructed so that it not only pulls oil a length of under thread but also grips and holds the under thread. For this purpose the wire forming the pulloff arm 91 is bent into a coil 103. In forming the coil the wire is given a backward turn, as shown at 10 1, Fig. 14, and then is bent into the coil formation. This forms a tapering throat 105 which is so situated that when the pull-off arm swings into the dotted line position Fig. 16 the under thread to will be caught in the tapering throat 105 and will be gripped slightlv between the turns of the coil.

After the thread pull-011' arm 01 has thus operated to pull olf a length of thread and to grip the latter the under thread is cut by an under thread cutter 106. (see Fig. 15) which is also actuated by the slide 96. This cutter is pivotally mounted at 107 on the top of the work-sup porting arm 3 and beneath the workholding plate 25, said plate being removed in Fig. 15 to better show the construction of the cutter. This cutter 106 has a cutting edge 108 at its end which operates directly beneath the throat plate 109. Said cutter member 106 is connected at its rear end to a block 110 which is slidably mounted in a slot 111 in the arm 3, said block having on its under side a pin 112 which is confined between two

arms

113 and 114 carried by the end of the slide 96. The cutter member 106 also has a pin 115 depending therefrom and operating in an inclined slot 116 formed in the bed.

With this construction the movement of the slide 110 toward the rear will produce a forward swinging movement of the under thread cutter due to the movementof the pin 115 in the slot 116, such forward movement causing the cutting edge 108 to engage the under thread leading from the work through the throat plate 109 and thereby severing said thread close to the work.

The

arms

113 and 114 are spaced apart so as to allow some lost motion and the purpose of this is to provide the proper time relation between the operation of the thread pull-off and the cutter, it being desirable that the pulloff should operate first to pull off a length of thread after which the cutter should operate to cut the thread. lVith the parts in the position shown in Figs. 15 and 16 it will be observed that during the first or initial movement of the slide 96 the pull-off arm 91 will be swung toward the dotted line position Fig. 16 thereby pulling olf a length of thread and after the lost motion between the arm 11 i and the pin 112 has been taken up then dur ng further movement of the slide 96 the block 1 it) will be actuated thereby operating the under thread trimming knife.

The pin 95 is shown as acted on by a return spring 117 which restores the parts to their normal position as the arm 65 passes down onto the low portion of the 1am I have also provided herein a safety device which has for its object to prevent the operation of the thread trimmers while the s'titchforming mechanisn'i in operation. In other words, this safety device positively holds the thread trimmers inoperative while the stitching is being performed and releases the thread trimmers for operation only when the stitchforming mechanism has been brought to rest.

It will be remembered that the trimmers set in operation by the action of the stop motion in giving the arm (32 a momcn turning movement into the dotted line position Fig. 5 thereby to release the clutch dog 60 and allow the clutch pin 58 to become operative to clutch the cam 54 to the constantly-operating member 56. The safety device is in the form of a latch which is adapted to lock the arm (32 in the full line position Fig. This latch is shown at 120 and is pivoted to the train: at 121. It is formed at its upper end with a nose 122 which is adapted to latch over the portion 123 of the arm (32, said portion having a lip 124 which engages the nose 122 and thus locks the arm 62 from movement. This locking latch 120 is shown in its inoperative position in Fig. 4 and it is acted on by a spring 12.? which tends to swing it into its operative position in engagcn'ient with the lip 12%.

Means are provided whereby the locking latch 120 will be moved into its inoperative position when the clutch-controlling rod is released and is shifted into a position to render the stop motion operative. The arm 64 is provided with a lug 126 which engages a projection 127 on the locking latch when the stop motion block moves from the position it occupies when the driving pulley T is i'flutchcd to the shaft 6 into the stopping position shown in Figs. 4 and 6 and such engagement of the ear 126 with the projection 127 swings the latch into the position shown in Fig. i and thus unlocks theleverarm 62. \Vhen the rod 10 is shifted to the left Figs. 4 and 6 to start the machine by clutching the pulley 7 to the driving shaft 6 such movement carries the car 126 away from the lug 127 and the spring 125 then acts automatically to swing the locking latch into its operative position, in which position it locks the arm 62 from movement and thus prevents the possibility of the cam 54 being clutched to the constantly-driving member 56. When, however, the stop motion is actuated to bring the serving mechanism to rest then the locking latch 120 will be released so as to permit the operation of the thread trimmers as above described.

The construction is such that when the clutch-controlling rod 10 is shifted to clutch the driving pulley 7 to the shaft 6 the locking latch 120 will come into its operative position just before the stop dog 8%) is moved out of engagement with the. stop cam 90. ace the arm 62 will be locked just before the clutch is started in operation, the advantage of which is that there is no possibility that the cutters can be actuated accidentally except at the proper time in the sequence of operations.

While I have illustrated herein a selected embodiment of the invention 1 do not wish to be limited to the constructional features shown.

I claim:

1. Ina buttonhole sewing machine, the combination with stitch-forn'iine mechanism, of work-holding means, a thread holder, a thread cutter l'iaving two op iositely-disposed cutting edges, means to move the thread cutter in one direction to cut the thread at the end of the seam and in the other direction to cut the thread at the beginning of the seam.

2. In a sewing machine adapted to sew a short seam and then come to rest. the combination with stitch-forming mechanism, of Work-holding means, a thread holder, a thread cutter having two oppositely-disposcd cutting edges, power-actuated mechanism to more the cutter in one direction, and a spring to move it in the other direction. movement in one direction operating to cut the thread at the end of the seam and in the other direction at the beginning of the seam.

3. In a sewing machine adapted to sew a short seam and then come to rest, the comhination with stitch-forming mechanisn'l, of work-holding means, a thread holder. a thread cutter having two opposirely-disposed cutting edges, power-actuatml mechanism to move the cutter in one direction at the end of the seam thereby to trim the thread between the holding means and the work, a spring to move said cutter in the opposite direction at the beginning of the scam thereby to trim the held end of thread.

4. In a machine adapted to sew a short seam and then come to rest. the combination with a stitch forming meciianism. of workholding means, a thread holder. :1 illifiihl cutter haying two oppositely-disposed cutting edges, power-actuated mechanism to operate the thread holder and the cutter at the end of the seam to cause the thread holder to hold the thread and the thread cnttcr to cut the thread between the holding means and the work. springs acting on said holder and cutter and opposing the power-actuated movement thereof. a latch to hold said holder and cutter in the position given them by the power-actuated means, and means operated by the feeding" movement of the work-holding means to release the latch to permit the holder and cutter to return to their normal position after he sewing operation has started.

5. In a huttonhole sewing machine. the combination with stitch-forming merhmiism, of work-holding means. a driving and stop motion device for driving the stit lntorming mechanism and blin ing it to rest, a thread holder, :1 thread cutter, power actuated mechanism controlled by the stop motion device when thestitch-formingmet-haniamisbrought to rest to cause the holder to hold the thread and the cutter to cut the thread between the holding means and the work. and s; 'ing' mechanism operating to actuate the cutter to cut the held thread at the beginning of the seam.

6. In a sewing machine adapted to sew a short seam and then come to rest. the combination with stitch-forming nw-hanism. of work-holding means, a stop motion device for operating the stitch-forming me hanism and bringing it to rest at the end of the seam. power-actuated means controlled by the stop motion device to pull ott 11 length ot needle thread, clamp the needle thread. cut the needle thread between the thread-clamping means and the work, pull oti' a length of under thread and cut. the under thread, and spring means o 'ierating to cut the upper thread at the beginning of the seam. v

7. In a sewing machine adapted to sew a short seam and then come to rest. the combination with stitch-forming mechanism, of work-holding means, a stop motion device for operating the stit h-torming mechanism and bringing it to rest at t he end of the seam, power-actuated means controlled by the stop motion device to pull ott a length of needle thread, clamp the needle thread. cut the neodle thread between the threa( i-clamping means and the work, pull otf a length of under thread and cut the under thread. spring means operating to cut the upper thread at the beginning of the seam, and means to lock the power-actuated mechanism t'rom operation while the stitclnforming mechanism is in operation.

8. In a huttonhole sewing machine, the combination with stitch-forming mechanisl'n, o't work-holding means, means to give the work-holding means a feeding movement, a driving and stopping mechanism tor operating the stitcl1for1ning mechanism and bringing it to rest at the end of the seam, a thread cutter having two cutting edges, means operating independently of the stitchtorming mechanism but set in operation by the stop motion to move the thread cutter and cause one cutting edge thereof to trim the thread at the end of the buttonhole, and

means controlled by the feeding movement of the work-holding means to give the thread cutter a movement to cause the other cutting edge to trim the thread at the beginning of the seam.

9. In a buttonhole sewing machine, the combination with stitch-traming mechanism, of wm-k-holding means, means to give the work-holding means a feeding nmvement, a driving and stopping mechanism for operating the stitch-forming nechanism and bringing it to rest at the end ot the "am, a

thread cutter having two cutting edges. a thread holder. means operating independently of the stitch-forming mechanism but set in operation by the stop motion to cause the thread holder to grip the thread and the threadcuttertocutthethrcad with one cutting edge at the end of the buttonhole, and means controlled by the tecding movement of the work-holding means to cam-e the thread cutter to cut the thread with the other cutting edge after the seam has begun and to actuate the thread holder to release the trinnned end.

it). In a sewing machine, adapted to sew a short scam and then come to rest. the combination with stitch-forming mechanism, ef work-holding means, a thread cutter ha \ing' two oppositely-dis]iosed cutting edges. and means to move the thread cutter in one direction to cause one cutting edge to cut the thread at the end of the seam and in the other direction to cause the other cutting edge to cut the thread at the beginning of the seam.

11. In a. sewing machine adapted to sew a short seam and then come to rest, the combination with stitch-forming mechanism, of work-holding means, a thread cutter having two oppositelydisposed cutt inc; edges, poweractuated mechanism to move the cutter in one direction to cause one cutting edge to cut the thread at the end of the seam, and a spring to move the cutter in the opposite direction to cause the other cutting edge to cut the thread at the beginning of the seam.

12. In a sewing machine adapted to sew a short seam and then come to rest, the combination with stitch-forming mechanism, of work-holding means, a thread cutter having two oppositely-disposed cutting edges, power-actuated mechanism to move the cutter in one direction, and a spring to move it in the other direction, movement in one direction causing one cutting edge to cut the thread at the end of the scam and in the other direction causing the other edge to cut the thread at the beginning of the seam.

13. In a sewing machine adapted to sew a short seam and then come to rest, the combination with stitch-forming mechanism, of work-holding means, a thread cutter havmg two oppositely-disposed cutting edges, power-actuated mechanism to move the cutter in one direction at the end of the seam,

to cause one cutting edge to trim the thread, a latch to hold said cutter in a position placed by the power-actuated mechanism, means to release the latch at the beginning of the seam, and a spring to give said cutter a return movement thereby to cause the other cutting edge to trim the thread a second time.

14. In a buttonhole sewing machine, the combination with stitch-forming mechanism, of work-holding means, a thread holder, a thread cutter having two oppositely-dis; osed cutting edges, means operative at the end of the seam to give the thread holder a movement to cause it to grip the thread and subsequently to operate the cutter to cause one edge thereof to cutthe thread, and means operativ a ter the next stitchin operation has begun to move the cutter in the opposite direction to cause the other edge to cut the held end of thread and then to move the thread holder to reiease said thread {A ,iuent,

15. In a buttonhoie sewing machine, the combination with stitehforming mechanism, of work-holding means having a Feeding movement, a thread holder, a thread cutter having two oppositely-disposed edges, means operative at the end of the seam to cause th thread holder to grip the thread and suhsequently operate the cutter in one direction to cause one cutting edge thereof to cut the thread, and means operated by the feeding moven'ient of the work holder after the next stitching operation has begun to more the cutter in the opposite direction thereby to cause the other cutting edge to trim the thread and then to move the thread holder to release the thread fragment.

16. In a buttonhole sewing machine, the combination with stitch-forming mechanism, of work-holding means, a thread holder, a thread cutter having two opposit-elydisposed cutt ing edges, power-actuated mechanism 0perative at the end of the seam to move the holder into a position to grip the thread and to move the cutter to cause one edge thereof to trim the thread between the holder and the work, and means operative after the next seam has hegnn to move the cutter in the 0pposiie direction to cause the other edge to cut the held thread and then to move the thread holder to relez re the thread fragment.

ti. In a buttonhote sewing machine, the combination \Vi'i h stitchforming mechanism, of work-holding means having a feeding movement, a thread holder, a thread cutter having; two oppositely-disposed cutting edges, power-actuated mechanism operative at the end of the seam to move the holder into a position to grip the thread and to move the etltiOi' to rause one edge thereof to trim the thread between the holder and the Work, and means operated by the feeding movement of the work holder after the next stitching operation has begun to move the cutter in the opposite direction to cut the held end of iili't ad and then to move the thread holder to rehz-zse, the thread fragment.

in testimony whereof, I have signed my name to this specification.

AXEL F. CARLSON.