US1738186A

US1738186A - Cutting attachment for sewing machines

Info

Publication number: US1738186A
Application number: US182664A
Authority: US
Inventors: Krasa Albert
Original assignee: ST Regis Paper Co
Current assignee: ST Regis Paper Co
Priority date: 1927-04-11
Filing date: 1927-04-11
Publication date: 1929-12-03
Anticipated expiration: 1946-12-03
Also published as: FR652442A; BE350419A; NL40796C; GB288552A

Description

Dec. 3, 1929.

5 Sheets-Sheet l Filed April l1, 1927 Dec. 3, 1929. A. KRAsA 1,738,186

CUTTING ATTACHMENT FOR SEWING MACHINES Filed April 11, 1927 5 sheets-sheet 2 C) 5 v 3mm A ./Uertfrasa.

331, @AAM 7 @LM 5 Sheets-Sheet 5 .fert Kras a.

A. KRASA Dec. 3, 1929.

CUTTING ATTACHMENT FOR SEWING MACHINES Filed April 11l 1927 Dec. 3, 1929. A KRASA 1,738,186

CUTTING ATTACHMENT FOR SEWING MACHINES Filed April 11; 1927 5 sheets-sheet k4 ,41beftmsawww.

Dec. 3, 1929. A. KRAsA CUTTING .ATTACHMENT FOR .SEWING MACHII-JES Filed April -11I 1927 5 Sheets-Sheet 5 atto@ new;

Patented Da-n 3. 1929 UNITED STATES PATENT OFFICE ALBERT KRASA, OF CHICAGO, ILLINOIS, ASSIGNOR, BY MESNE ASSIGNMENTS, TO ST. REGIS PAPER COMIANY, F NEW YORK, N. Y., A CORPORATION OF NEW YORK CUTTING ATTACHMENT FOR SEWING MACHINES Application filed April 11,

My invention relates to a cutting attachment for a sewing machine, and has as its object to provide a cutter particularly adapted tosever reinforcing tape between bags the mouths of which have been closed by a seam sewed through the tape. The object and details of my invention will appearmore fully as the description proceeds.

In the accompanying drawings, which form apart of this specification, Figure 1 is a side elevation of one form of apparatus embodying my invention. Fig. 2 is a view of the apparatus shown inFig. 1, looking from beneath. Figs. 3 and 3 are cross-sections on the lines 3-3 and 4-4, respectively, in Fig. 1. Fig. 5 is a cross-section on the line 5--5 of Fig. 3. Fig. 6 is a cross-section on the line@ 6--6 of Fig. 1. Figs. 7 and 8 are details of 4portions ofthe clutch operating mechanism. Fig. 9 is similar to Fig. 8, but shows the parts in a different position. Figs. 10 to 15 are diagrammatic views of the` feed dogs and tape cutting knives in different positions.

The apparatus disclosed shows my improvements applied to a'sewing head substantially like that disclosed in the co-pending application of A. M. Bates and myself, Serial No..616,37 2, whichihas eventuated in Patent' No. 1,625,r 81, issued April 26, 1927.

In the use of such apparatus as disclosed in that application, the tops of bags are fed in succession through the sewing machme, which applies reinforcing tape to the s ides of the mouths ofthe bags andsews a continu ous seam'through the reinforcing tape and the interposed walls of the bag. Theimprovements forming the subject of this mventlon relate particularly to means for severing the reinforcing tape between successive bags.

As will appear most clearly from Figs. 2

and 6, the tape is fed to position in front of the needle by

tape guides

21 and 22. Afterl the top 23 of onepbag has been completely sewed, the seam is continued through tape 24 beyond the edge of the bag to the top of the next bag 25; In order to disconnect the two bags from each other, it is necessary to cut the tape 24.

.In the apparatus disclosed, the tape is cut*` 50 by a stationary knife and a movable knife.

1927. serial No. 182,664.

The stationary knife 26 is mounted in a knifecarrier 27 and projects into a suitable slot 28 in the throat plate 29, so as to be located at' one side of the path of the tape.

Movable knife 3() is mounted on the oppo- 55 site side of the tape in a knife carrier 31, which is reciprocable in suitable uides to move the knife 30 across the path o? the tape and sever it against fixed knife 26.

The movable knife is actuated by carrier 31 60 which is connected by a link 32 to an arin 33 on a rock shaft 34. The other end of rock shaft 34 carries an arm 35 connected by a link 36to a crank 37 on a crank-disc 38 attached to the end of a clutch-shaft 39. As will be read' .65

ily seen, the reciprocating knife 30 is reciprocated once for each revolution of the clutch shaft 39.

The clutch-shaft 39 is parallel to the main shaft 4() of the sewing machine. A pinion 41 .7o on the main shaft of the sewing machine meshes with a clutch-gear 42 mounted loosely on the clutch-shaft.

Clutch-gear 42 comprises a disc portion 43 carrying gear teeth around its periphery 75 and 'cut away to form a recess 44 in which is mounted a flange 45 of clutch member 46. Gear 42 also comprises a collar 47 which fits gver a sleeve 48 mounted on the clutch-shaft Pins 49 project from clutch member 45 through slots 50 in disc member 43, and are connected by springs 51 with pins 52 fast on disc member 43. Bumper members 53 are securely fastened bymean's of screws 54 `to g5 disc member 43. These bumper members are in position to contact pins'49 when the pins 49 approach the limits of slots 50 away fromv Adjacent clutch member 46 there is a cam e0 member v-55 which is secured rigidly to the clutch shaft. In the construction shown there is a notch 56 in the clutch shaft and a groove 57 in cam member 55, and a pin 58 driven through this groove and slot prevents a relative turning movement of the cam and shaft while permitting slight relative longitudinal adjustment.

Cam member 55 carries a disc cam 59. A

clutch dog 60 is pivoted at 61 to disc 59. Dog 10U shown, similar to pin 88.

has a. tooth 62 at .one end in position to engage in either of two notches 63 in the hub portion of clutch member 46. A spring 64 normally urges dog 60 into engagement with clutch member 46. The dog is provided with a projecting finger 65 which engages a trip pin 66 and holds the dog out of engagement with clutch member 46, except when the trip pin is withdrawn.

A trip arm 67 is pivoted at 68 to a bracket 69 in position to have its end 70 contact bags immediately beneath the seam as they are fed through the sewing machine. Another arm 71 extends from pivot 68 and forms with arm 67 a bell crank lever. A pin 72 in the end of arm 71 engages a fork 73 on the end of an arm 74 fixed on a rock shaft 75. A member-76 is fixed in adjusted position and has a notch 77 the ends of which act as limits for the movement of a pin 78` extending from arm 71. In this way the extent of the rocking movements of arm 67 and shaft 75 are limited. i

At the other end of rock shaft 75 there are two

arms

79 and 80. To the end of arm 79 there is pivoted a trip-releasing pawl 81. The free end of this pawl is provided with a notch 82 and normall rests against an arm 83 of a rocking mem er 84 pivoted upon a horizontal pin 85. Pawl 81 has a lug 86 to which there is attached a coiled spring 87 .the other end of which is attached to a fixed pin l88.

To arm 80 there is pivoted a trip pawl 88 similar to trip pawl 81, except that pawl 88 is provided with a tooth 89 instead of notch 82. The shape of tooth 89 is shownin dotted lines in Fig. 3.- The end of pawl 88 rests against an arm 90 extending in an opposite direction from arm 83 from the pivot of rocking member 84. A lugV 91 extends from! pawl 88 andhas attached thereto a spring 92 whose other end is fixed to a pin not Trip pin 66 is slidable in a hole 93 in a fixed bracket 94 which supports the clutch shaft and its attachments. l pin 66 there is a groove 95 in which there fits a member 96 projecting from an arm 97 mounted on member 84 and extending at right angles to

arms

83 and 90. Extending from the end of arm 97 in the opposite direction from member 96 there is a lug 98. e e

Pivoted at 99 in bracket 94 there is a three-armed member 100. One arm 101 of this member carries a cam roller 102 in engagement with the periphery of 4disc cam 59. Another arm 103 of member 100 is connected by a strong spring 104 to a pin 105 fixed to In one side of member 109 carries arcross-p'iece 111. At each end of cross-piece 111 there is a pair of pins 112 between which pins a

pawl

81 or 88 is positioned. A pin 113 is adjustably fixed by a set screw 114 in position to limit the entrance of the respective pawl between pins 112.

In the construction shown, the' tape cutting knife 30 is adapted to operate between the usual presser foot 115. and an auxiliary presser foot 116. Presser foot 116 is preferably pivoted at 117 to a carrier 118 for limited oscillation with respect to the carrier. It has an upturned guiding toe 119.

It is preferable to employ a movable tapedepressing member 120 pivoted to the main presser foot and normally depressed by a spring 121. n.

`Knife 30 is constructed with a guide extension 121. The end of extension 121 is beveled so as to slide from the end of fixed knife 26 and bring the cutting edge proper 122 of the reciprocating knife into shearing engpgement with the cutting edge of the fixed mi e.

It will be understood that rthe* mechanism shown comprises

feed dogs

123, 124 in suitable relation to the presser feet. Furthermore, in the mechanism disclosed, there is a trimming knife 125 mounted in a slide-way in the feed dog carrier, in a manner similar to that disclosed in the previously mentioned application, and which does not need to be further described in this case. l 1 The operation of the apparatus is as folows: 1

Assuming the parts to be in the positions in which they are shown in Figs. 1 to 7, the clutch-dog is engaged by the trip pin and held out of contact with clutchmember 46. Gear 43 and clutch member 46 continue to rotate about clutch-shaft 39 until the bag engaging -end 70 of arm 67 has been closed. Then springs 87 and 92 pulling downward on the trip pawls and the

arms

79 and 80 to which they are attached, rock shaft 75 and throw end of arm 67 past the edge of the closed bag.Y IVhen this action takes place, notch 82 of pawl 81 rests upon and drives downward arm 83 of oscillating member 84. When member 84 is thus oscillated, arm 96 is moved upward, as shown in Fig. 5, and' end 66 of the trip pin is withdrawn from engagement with the clutch pawl. Thereupon the notched end of the pawl is pressed against rotating clutch member 46 and engages in the first notch which comes under it.

When the clutch-pawl is engaged in a notch in member 46, the member 46 is arrested and stretches springs 51 until their tension starts rotation offclutch member 46 and the pawl and member 55 therewith, or until this result is achieved by contact of pins 49 with abutment blocks 53.

Thereafter member 55 continues to turn and 130 drive clutch shaft 39 with its crank until a complete revolution of shaft 39 has taken place. By this revolution rock shaft 34; is oscillated and cutting knife 30 is driven downward and then drawn upward.

During the revolution of shaft 39, cam 107 operates in fork 108 to move the fork downward and to raise

pins

112, 113 upward, thereby moving the trip pawls upward out of engagement with

arms

83 and 90 of oscillating member 84. Arm 106 is moved to the position in which it is shown in Fig. 8 beforetrip pawl 81 is released from arm 83, so that the end of arm 106 temporarily blocks the downward movement of arm 96 by engaging lug 98 thereon. However, immediately after the position in which the parts are shown in Fig. 8, roller 102 runs down on cam run 126-of cam 59 and moves arm 106 out of engagement with lug 98 and allows spring 127, attached to arm 90 and to fork 108, to oscillate member 84 and drivepin 66 downward so .that its end projects in the path of the clutch-dog and throws it out of engagement with clutch member 46 when a revolution of shaft 39 is completed.

After pin 66 is thus projected, rotation of cam 107 returns pins 112 and 4113 to their original positions and allows the trip pawls to again engage

arms

83 and 90. If anotherV bag has `been fed to the machine so that it contacts end 70 and oscillates shaft. 75 before the return of the trip pawls into engagement with

arms

83 and 90, shaft 75 is held with

arms

79 and 80 raised, as shown in Figs. 1, 3 and 5, so that the lower end of pawl 88-rests idly against arm 90, and tooth 82 of pawl 81 just clears the top of arm 83. Thus the parts will be in the position in which they are shown in Figs. 1 to 6, and the clutch and cutter will remain at rest until this bag moves out of contact with end 70, whenend 70 will drop and the movements described above will be repeated. If no bag is in contact with end 70 when trip pawls 81 and88 are

re-engagedfwith arms

83 and 90, end 70 will remainlowered, and

arms

79 and 80 will b e held down by

springs

87 and 92. Thedownward movement of

arms

79 and 80 is limited by the contact of pin 7 8 with the opposite wall of notch 77 from that with which it is shown in contact in Fig. 6, and the parts are so proportioned that, 1n

v this position, tooth 89 of pawl 88 is just below arm 90 with that arm in the position in which it is shown in Fig. 5. This `allows pin 66'to remain in its stopping position as shown in Fig. 5, until end 70 is raised. The raising of end 70 by the next bag sewed rocks shaft and raises arm 80 and pawl 88.

Since tooth 89 of pawl 88'l is hooked underneath arm 90, raising end 70 raises arm 90 and' withdraws pin 66 out of the path of theI clutch dog, Thereafter the dog engages clutch member 46 and the cutting is repeated as descrihedloove.

cutter cuts the tape between baas but once when there is just enough spacebetween the bags to admit end 70, because end 7 0-is raised by the next bag before the first cut is nompleted; but in all cases where there is more than this minimum space between bags, the falling of 70 allows pawl 81 to descend and lower arm 83 and withdraw pin 66, thus instituting a cut at the desired distance from the edge of the finished bag, andthe raising" of end 70 by an oncoming bag raises pawl 88 and arm 90 and againwithdraws pin 66, instltuting another cut at the desired distance from the oncoming bag.

When the machine is being run at high speed, the clutch sh-aft and its associated parts acquire considerable momentum during the cutting operation. This momentum 4might continue the movements ofthe parts after the clutch-dog is disengaged if it were not for the provision of a safety device.

Cam 59 is provided with a socket 128 into which roller 102 fits when the clutch shaft i has arrived in position to result in the disengagement of the dog by pin 66. Spring 104 1s of sufficient strength to normally stop'y the movement of the clutch shaft and associated parts when roller 102 enters notch 128; but when spring 104 is n'ot suflciently strong to overcome the momentum of the parts and prevent their turning beyond the intended point, roller 102 can ride up out of the notch only as far as shown in Fig. 9. At this point arm 106 engages projection 98 on arm 97. This forms apositive limit to the movement of the cam and clutch shaft asn long as pin 66 and consequently projection 98 remain in the posit-ions in which they are shown in Fig. 5, After the device is stopped, inthe position shown in Fig. 9, the action of spring 10e through roller 102 normally returns the cam Y to the intended rest position, with the roller resting in notch 128. j

It will be notedi that the gearing ratio is such that the shaft 39 makes one revolution 'While the main sewing machine shaft makes two revolutions. In order to prevent interference of the cutting operation with the feeding operatiomit is necessary that the cutting shall be vtimed to take place between successive movements of the feed dog. The way in which this is accomplished is illustrated in I Figs. 10 to 15. The parts are so arranged that while the knife starts downward nearlng the forward movement of the feed dog,

as indicated in Fig. 10, it does not contact the v material until the limit of the feeding movement of the feedldog is completed, as shown in Fig. 11. The cutting is thenaccomp1ished while the feed dog is moving to the rear, as shown in Figs. 12, 13 and 14.-.

The projecting guide finger 121 of the movable knife vdoes not entirely recede` from the path of the material'until the feed dog has moved forward once more,as shown in Fig. 15, but this does' not interfere with the movement of the bag and qits attached tape.

The tape may be drawn upward to. some extent by the upward movement of the cutting knife, as indicated in Fig. 14, but the tape-depressing member attached to the -foot promptly returns the tape to its proper position after the cutter is raised.

Two notches are provided in clutch member 46 so that the clutch shaft and cutter is driven the first time that the main shaft of the sewing machine arrives at proper position after the Itrip )ing of the clutch.

' It will'be seen th mechanism I have provided apparatus which will turn the knife-moving shaft at only onehalf the speed of the main shaft of the sewing machine, and still the knife will not interfere with the proper4 feeding of the material through the sewing machine. Cutting of the tape at the proper interval after a bag has passed through the sewingmachine is insured byv this mechanism. If more tape than isidesirable enters linto the seam between two successive bags, vthe tape is again cut when another bag is presented. In other words, the tape is cut at the desired distance from each edge of the bag, regardless of the size of the bag or the distance apart of successive bags. In this way suicient extension of ythe tape to insure secure closure is provided,

and unnecessary extension is avoided. The finished packages resulting from this closure apparatus are, therefore, uniform.

While the movement of the two feed dogs is approximately parallel with each other, the dog-carrying member oscillates at-a polnt below the feed dogs, as viewed on Figs. 10 to 15. The result is that the feed dog 124 moves a less distance to and from the work than does feed dog 123, and, therefore,.feed

dog 124 grips the work slightly sooner` than does feed.dog 123, and tends `to move 1t forward a slightly greater distance. This fact is utilized' in parting the tape. The rst feeding movement of the feed dogs after the tape is severed tends to move the severed end slightly farther than the end still connected to the source of supply, so as to open up a gap such' as shown at 129 on Fig. 15.

lVhile theapparatus is shown as particularly vdesigned for closing filled bags, it will be understood that similar mechanism might be provided for severing a reinforced seam between successive empty bags or other ar- Ves ticles; and while the cutter has been shown in connection with a particular type of sewing machine, it will be understod `that the form of the sewing machine to which it is attached may be modified as desired without affecting the scope of the invention.

What I claim is: ff

l. In combination, a sewing device adapted to sew a continuous seam across successive at by the above describedarticles, a cutter through which the seam passes as it moves away from said device, and means to actuate the cutter and make one cut across' the seam a predeterminedJ distance in advance of the front edge of an article and to make one cut across the seam a predetermined distance behind the rear edge of an article.

2. In combination, a sewing device adapted to sew a continuous seam across a plurality of articles, and a seam cutter towards which the seam moves from said device, a trip in the path of the articles at one side of the seam and adjacent the cutter, and connections from the trip operating the cutter to make one cut across the seam a, predetermined distance in advance of theforward edge of the article and to make one cut across the seam a predetermined distance behind the rear edge of an article.

3. In combination, a sewing device adapted to form a continuous seam across a plurality of drticles, a seam cutter towards which the seam moves' from said device, a continuously operating source of power for the cutter, a one-revolution. clutch connecting the source of power with the cutter, and means actu' ated by the articles to close the clutch when the forward edge of an article approaches the cutter to a predetermined point and when the rear edge of an article has passed the cutter a predetermined distance.

4. In combination, a device adapted to sew a continuous tape to a series of bags, a cutter towards which the tape moves from the device, operating means for the cutter, a trip in the path ofthe bags at one side of the tape, 'and connections whereby the cutter is actuated to make one cut across the tape and seam sewed therethrough when the trip moves from its normal position to a position resting against a passing bag and when the trip moves from its position resting against a passing bag to its normal position.

5. In combination, a sewing` device and a seam cutter towards which the seam moves from said device, a trip movable to two positions in accordance with the passage-of work through the machine, and connections `be tween the trip and the cutter causing' the cutter to be actuated once for each movement of the trip from either one of its positions to its other position.

6. In combination, a sewing machine having a needle, a feed dog, and a main shaft operating the needle and feed dog in timed relation, a seam cutter in position to sever a seam sewed by the needle, a cutter shaft adapted to actuate the cutter to make one cut during one revolution thereof, and gearing connecting the cutter shaft with the main shaft and driving the cutter shaft one revolution for two revolutions of the main shaft, the connection from the cutter shaft to the cutter being timed so that the cutter crosses the seam during one idle stroke of the feed dog.

7. In combination, a sewing machine having a needle and feed dog, and means driving the needle and feed dog in timed relation, a reciprocating cutter, and connections adapted to reciprocate the cutter once during two reciprocations of the needle and feed dog, the connections being timed to move the reciprocating cutter into and out of the path of the seam during one idle stroke of the feed dog.

8. In combination, a sewing machine having a needle and feed dog, and means driving the needle and feed dog in timed relation, a reciprocating `seam-cutter, connections adapted to reciprocate the cutter once during two reciprocations of the needle and feed dog, the connections being timed to move the reciprocating cutter into andout of the path of the seam during one idle stroke of the feed dog. a stationary cutter on the opposite side of the path of the scam from the normal position of the reciprocating cutter, and in position to have shearing co-operation with the reciprocating cutter, and a guide finger extending from one side of the reciprocating cutter and adapted to guide the reciprocating cutter into shearing relation with the stationary cutter.

9. A seam-cutter for a, sewing machine comprising a stationary knife on one side of the path of thescam, a reciprocating knife normally on the other side of the path of the seam, and a finger extending from one edge of the reciprocating' knife towards, but not to, the stationary knife when the knives are separated, the reciprocating` knife being so mounted as to tend to abut the stationary knife, and the end of the finger being bevelled to slide from the edge of the stationary knife and guide the cutting edge of the reciprocating knife into shearing relation with the stationary knife, and the edge of the reciprocating knife being beveled in the opposite direction from the end of the finger.

10. In combination, a sewing'machine having a main shaft, a cutter shaft, a seam-cutter driven by the cutter shaft, a one-revolution clutch on the cutter shaft driven by the `main shaft, saidone-revolution clutch comprising a stop means, and said stop means comprising a cam having a stop socket therein, 'a cam roller, a spring pressing the roller against.

. the cam and into the socket at the stop position, a trip linger for closing the clutch, and a member connected with the cam roller and engaging said finger before the roller is moved entirely out of said socket, when said finger is in open-clutch position.

11. In combination, a sewing machine having a main shaft, a seam-cutter attached to the sewing machine and having a cutter shaft, and driving connections between the main shaft and the cutter shaft, said driving connections comprising a limited lost motion connection and spring means tending to turn the cutter shaft forward to the limit of said lost motion.

l2. In combination, a sewing machine having a main shaft, a cutter and a cutter shaft,

a member loose on the cutter shaft and connected to the main shaft to be driven once during a plurality of turns of the main shaft, and a clutch device between said member and cutter shaft, one member of said clutch comprising a dog and the other member of the clutch having therein a number of notches equal to the number of turns which the main shaft makes during one revolution of Said member, with any one of which notches said dog may co-operate. l

13. In combination, a sewing machine having a main shaft, a seam-cutter having a cutter shaft, a gear loose on the cutter shaft and meshing with a gear on the main shaft in two to one relation, and clutch means between the gear and the cutter shaft, one of the members of said clutch con'iprising a dog andl the other member having therein two oppositely disposed notches with either of which the dog may co-operate.

14. In combination, a device for sewing a continuous seam through successive articles, a sea1n-cutter, a continuously operating driving device for the cutter, a one-operation clutch for connecting the cutter tothe driving device for one operation of the cutter, a trip finger in the path of the articles as they move 1Lpast the cutter, a rock shaft to which the trip nger is attached, and two trip pawls connected tovsaid rock shaft, one of said pawls being` connected to trip the clutch when the shaft is rocked in one direction, and the other pawl being connected to trip the clutch when the shaft is rocked in the other direction.

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

ALBERT KRASA.