US1483308A - Thread trimmer for sewing machines - Google Patents

Description

1,483,308 J. KIEWICZ THREAD TRIMMER FOR SEWING MACHINES Een. 12, 1924;

Filed Sept. 27`. 1922 G'Sheets-Sheec 2 lll lll.. IIL

Feb. 12 1924.."-

. J. KIEWICZ THREAD TRIMMER FOR SEWING MACHINES Filed sept. 2v, e sheets-snai Figli lnvenor. John Kewic? Feb. 12,1924. 1,483,308

y J.,KIEWICZ v THREAD 'lRIMMER FOR SEWING `MACHINES v Filed Sept. 27, 1922 6 Sheets-Sheet, 5

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nvenTov Feb. l2, 1924.

' 1,483,308 J. KlEwlcz N THREAD TRIMMER Fon SEWING MACHINES `Filed Sept. 27. 1922 6 Sheets-sheet 6 Patented Feb. l2, i924.

NET STATES PATENT FFECE.

JOHN KEWICZ, 0F BOSTON, MASSACHUSETTS, ASSIG-NOR TO THE REECE BUTTON HOLE MACHINE COMPANY, OF BOSTON, MASSACHUSETTS, A CORPORATION 0F MAINE.

THREAD TRIMMER FOR SEWING :MACHINES Application filed September 27, 1922. Serial No. 590,973.

T o all whom t may concern:

Be it known that l, JOHN l'inwicz, a citizen of the United States, and resident of Boston, county of Suffolk, State of Massachusetts, have invented an Improvement in Thread rTrimmers for Sewing Machines, of which the following description, in connection with the accompanying drawings, is a specification, like characters on the drawings representing like parts.

This invention relates to sewing machines of the type adapted to sew a short seam and then come to rest, and it has particular reference te means for trimming the under thread beneath the throat plate at the end of each seam.

The invention is in the nature of an improvement on the thread-trimming device illustrated in my co-pending application Ser. No. 552,926, filed April 15, 1922. The sewing machine shown in said application is provided with the usual loose pulley and a fast pulley, the 'driving belt being shifted from the loose pulley to the fast pulley to operate the machine and being returned to the loose pulley when the machine is stopped. In said application the thread cutter isactuated from the loose pulley when the belt is shifted from the fast pulley to said loose. pulley at the completion of the yseam and one feature of my present invention relates to an improved mechanism for actuating the thread cutter from the loose pulley Another feature of the invention relates to an improved form of thread cutter which is o f that type that operates first to pull off a length of the under thread from the shuttle and then to sever said thread close to the work.

In order to give an understanding of the invention I have illustra-ted in the drawings a selected embodiment thereof which will now be described after which t-he novel features will be pointed out in the appended claims.

In the drawings, Fig. 1 is a side view of a sewing mach-ine embodying my invention.y

. Fig. 2 is an end view.

Fig. 3 is a top plan view of the portion of the cutter actuating mechanism .which is associated with the loose pulley. y

Fig. 4 is an under-side view of the sewing machine bed frame illustrating the position of the under thread cutter.

Fig.. 5 is a plan vier7 of the removable plate of the bed frame to which the under thread cutter is secured.

Figs. 6, 7 and 8 are under side views thereof showing the parts in diiferent positions.

Fig. 9 is a section on the line 9 9, Fig. 8.

Fig. 10 is a detail view of the latch for holding the pin 48 elevated.

The sewing machine herein illustrated comprises the bed 1 which is pivotally supported on a base 2 vand. which carries the overhanging arm 3 that supports the vertically-reciprocating needle bar 4, the latter carrying the usual -upper needle 5.

The sewing machine is a two-thread sewing machine and the under thread is taken from a bobbin carried by a bobbin carrier situated beneath the bed plate 1 and during the formation of each stitch a loop of needle thread is carried around the bobbin carrier by means of a rotary hook all as usual in two-thread sewing machines. The bobbin carrier androtary hook are not illustrated in detail as they may have any suitable or usual construction but are shown generally at 6. Both the upper needle and the rotary hook are actuated from a driving shaft 7 by any suitable mechanism, which it is not necessary to describeherein, and said shaft has fast thereon a fast pulley 8 by which it is driven. Associated with the fast pulley 8 is a loose pulley 9 over which the driving belt 10 passes when the-machine is at rest.

To start the machine the driving belt 10 is shifted to the fast pulley 8, andwhen the machine is stopped again it is shipped back onto the loose :pullep 9. The belt is shifted from one pulleyto the other by a belt shipper .indicated at 11 which is carried by the end of an arm 12 extending from a bracket 13 forming part of the stop mot-ion. This bracket is carried by a rock shaft 14 which is mounted in the bed frame so that it can turn and also is arranged to have a movevment in the .direction of its length, the latter movement being `that which shifts the belt from one pulley toy the other. This bracket arm 13 forms partof the stop motion which brings the. machine to rest at the end of the stitc'ahing'y operation and when lil the machine is in operation said bracket arm is in the dotted line position FigA This bracket arm 13 has a stop dog 15 which co-operates with a stop cam 16 fast on the driving` shaft 7 for bringing the machine to rest at the end of the seam. When the macliine'is running and the bracket arm 13 is in the dotted line position the stop dog 15 is on the inside of the stop cam 16 and is free therefrom. At the end of the sewing operation the trip or catch holding vthe stopmotion in its inoperative position is released and the rock shaft 14 and bracket arm 13 are moved into the full line position Fig; 3 thus bringing the stop dog 15 into engagement with the stop cam 16. This stop cam has the rise 17, the valley 18 beyond the rise and the stop face 19 beyond the valley. The stop cam is rotating anti-clockwise Fig. 2 and when the stop dog is shifted into engagement with the cam at the end of the seam the high portion 17 of the cam will pass under ksaid stop dog and the latter will then drop into the valley 18 and be engaged by the stop face 19. The bracket arm 13 is acted on by a spring-pressed plunger 2O which resists upward movement thereof and thus applies a braking pressure while the high portion 17 of the stop'cam is passing under the stop dog. Said stop dog is carried by a plunger 21 slidably mounted in the bracket 13 and actedon by a spring 22 which is compressed when the stop face 19 `engages the stop dog thus bringing the parts to rest with a cushioned movement.

The parts thus far described are or may be all as usual in driving and stop mechanism of this type and form no part of my present invention. In fact the mechanism thus far described is substantially the same as is illustrated in my above-mentioned co- `pending application.

The work in which the seam is to be sewed (which in the present instance is the stitching on a buttonhole) is retained on a clamp plate 25 by means of usual work clamps 26.

The cutting device for trimming the under thread comprises a pull-off member 23 situated'beneath the clamp plate 25 and pivoted thereto at 24 and adapted to act on the under thread 27 at the end of the seam to draw off a length thereof, and a cutting member 28 also pivoted to the clamp plate 25 at 29 and having a cutting edge30 which is carried against they thread to trim the latter close to the work. y

The pull-oft' device and cutting member normally occupy the positions `shown in Figs. 5 and 6, the pull-off member being retained in this `position by a spring 31 and the knife by a spring 32. These lmembers are actuated at the end of each seam by `meansfof an actuator v3 3 inl the vform of a `Arod which `is vsldably sustainedl 'by the bed 1, and the rod in turn is actuated by the loose pulley 9 after the belt is shifted from the fast to the loose pulley.

The actuator 33 is provided with an arm 34 having a notch 35 and the pull-olf member 23 andcutter 28 are provided with cam ribs 36 and 37 which are adapted to be engaged by the walls 38 of the notch when the actuator moves from the position shown in Fig. 6 to that shown in Fig. 8. The engagement of the walls of the notch with the ribs causes the pull-off 23 and cutter 28 to be swung inwardly7 the inward movement of the pull-ofi' operating to pull off a length of the under thread 27 and the inward movement of the cutter operating to sever said thread.

The arrangement is such that when the actuator is given its operative movement it will first actuate the pull-ofi'l member to pull off a length of thread and will subsequently operate the cutter to sever the thread. The rib 36 is considerably longer than the rib 37 and is so situated that when the arm 34 has its operative movement from the dotted line position Fig. 6 into the full line position Fig. 8, said arm first engages the cam rib 36 and swings the pull-ott member 23 inwardly into the position shown in Fig. 7, and then one wall 38 of the notch engages the cam rib 37 and actuates the cutter thereby carrying it into the position shown in Fig. 8 and severing the under thread.

The rib 36 is slabbed ofl' as shown at 40 so that when the pull-ofi' member 23 has been swung into its operative position shown in Fig. 7 this slabbed-ofi' face stands parallel to the direction of movement of the arm 34 and, therefore, during the time that the cutter 28 is operating the pull-off member will be stationary.

The arm 34 and actuator 33 are normally retained in their inoperative position by means of a spring 41.

As stated above the movement of the actuator 33 is derived from the loose pulley 9 after the driving belt 10 has been shifted onto it when the machine comes to rest and the mechanism for accomplishing this, while somewhat similar to that shown in my copending application Ser. No. 552,926 is, nevertheless, an improvement thereon.

The bed 1 has a rod 42 slidably mounted therein and said rod carries a forked block 43, the arms of which embrace a lever 44 piv oted to the bed at 45. The outer end of this lever extends under the actuator 33 and the end of the latter is bent downwardly as shown at 46 so that swinging movement of the lever 44 from the full to the dotted line position Fig. 3, due to longitudinal movement of the rod 42, Awill give the operative movement to the actuator 33.

The rod 4 2 has fast thereon a bracket 47, and the latter sustains a pin 43 which is 7 arm and cutter.

vertically movable therein and when in lowered position is adapted to couple said bracket to a worm 49 that is fast to the loose pulley 9. The pin 48 is normally held in its elevated position out of engagement with the worm 49 by means of a latch 50, the end of which engages under a head 51 formed on the pin. Said pin is acted on by a spring 52 tending to move it downwardly.

During the stitching of the buttonhole the clutching pin 48 is retained in its elevated position by the latch 50 which is pivoted to the bracket 47 at 61 and is acted upon by a spring 54, and as the machine comes to rest at the end of a seam and the belt is shifted to the loose pulley 9 the latch 50 is released from the head 51 of the clutch pin and the latter is forced downwardly by its spring 52 into engagement with the worm 49. The rotation of the worm operates through the clutch pin to move the bracket and the rod 42 to the right in Fig. 1 or downwardly in Fig. 3 thus giving the movement to the lever 44 and actuator 33 necessary to operate the pull-ofi" As the pin 48 reaches the end of the worm it is automatically disengaged therefrom and this is provided for by making the worm with. the cam surface 53 which by its engagement with the endof the pin :torcesthe latter upwardly out of` en# gagei'nent with the worm groove. As soon as the pin has been -raised suiticiently the latch. 50, which is acted upon by the spring 54, snaps in under the head 51 and holds the pin raised, and the spring 55, which is connected to an arm 86 depending from the rod 42 restores the parts to the position shown in Fig. 3.

The releasing of the latch 50 from the head of the pin 51 is herein derived from the cushioning` movement which the clutch dog 15 has when it engages the stop face 19 of the stop cam at the time that the machine is brought to rest. The shank 21 of this clutch dog is provided with a block 56 adapted to engage one end of a lever 57 pivoted to the bracket 47 at 58, the other end 59 of the lever bearing against the end 60 of the latch 50. After the clutch dog 15 drops into the valley 18 the engagement of the stop face 19 with the clutch dog moves the latter to the left Fig. 2 against the action oi the spring 22 thus giving the cushioned stopping movement. This slight movement of the clutch dog causes the block 56 to engage the end of the latch-releasing lever 57 thereby giving it operative movement to release the latch 50 from the head of the pin and as soon as the pin is released it is carried into operative engagement with the worm by the spring 52 as above described.

The latch-releasing lever 5,7 and the latch 50 are shown as connected by a spring 63 which not only maintains'them in engagement but also serves to hold the free end of the lever 57 in the position shown in Fig. 3, in which position it is out of the path of movement ci: the block 56 as the bracket arm 13 moves from the'dotted to the full line position Fig. 3.

I claim:

1. In a sewing machine, the combination with work-holding means, of a pivoted pulloff arm situated beneath the work and hav ing a cam rib, a pivoted cutter also situated beneath the work and having a cam rib, and an actuator having a forked portion to engage said ribs and thus give said elements their operative move-ment.

2. In a sewing machine, the combination with work-holding means, of a pivoted pulloif arm situated beneath the work and having a cam rib, a pivoted cutter also situated beneath the work and having a cam rib, and an actuator having a forked portion to engage said ribs, the latter having such a relative position that during the movement of the actuator it operates first the pull-oil' arm and then the cutter.

3. Ineu sewing machine, the combination with work-holding means, of a pivoted pulloff arm situated beneath the work and having a cam rib, a pivoted cutter also situated beneath the work and having a cam rib, and an actuatoradapted to engage said ribs, the latter having such a relative position that during the movement ofthe actuator it operates first the pull-oli' arm and holds it in pulling-oli' position and thenoperates the cutter."

4. In a sewing machine, the combination with work-holding means, of` a pivoted pullolf arm situated beneath the work and having a cam rib, a cutter also situated beneath the work and having a cam rib, a slidable rod having a forked portion to engage said ribs thereby to actuate the pull-oil and cutter.

5. In a sewing machine, the combination with work-holding means, of a pivoted pulloit' arm situated beneath the work and having a cam rib, a cutter also situated beneath the Work and having a cam rib, a slidable rod having a forked portion to engage said ribs thereby to actua-te the pull-off 4and cutter, the rib on the pull-off being longer than the rib on the cutter whereby the pull-off is actuated first and then the cutter is actuated.

6. In a sewing machine, the combination with work-holding means, of a pivoted pulloi' arm situated beneath the work and having a cam rib, a pivoted cutter also situated beneath the work and having a cam rib, an actuator adapted to engage said ribs and give said pull-oil' and cutter their operative movements, a driving mechanism for the sewing machine comprising a driving belt, a fast pulley from which the machine is operated and a loose pulley, means to shift the belt from the tast to the loose pulley at the end of the sewing operation, and means actuated by the loose pulley to give movement to said actuator.

7. In a sewing machine, the combination with work-holding means, of a pivoted pullof arm situated beneath the Work and having a cam rib, a pivoted cutter also situated beneath the work kand having a cam rib, an actuator adapted to engage said ribs andv thus give said elements their operative movement, a driving elementv for operating the machine, means to connect said driving element to or disconnect it from the machine, and means actuated by the driving element after it is disconnected from the machine to give movement to the actuator.

8. In a sewing machine having a fast pulley, a loose pulley, al driving belt for said pulleys, and a stop motion including a belt shipper and a cushioned stop dog, the combination with said loose pulley 'and stop dog, of a worm fast to the loose pulley, a member normally disconnected from the worm, means controlled by the cushioning movement of the stop dog to connect said member to the worm, and a'thread cutter actuated by said member.

9. In a sewing machine having a fast pulley, a loose pulley, a driving belt for said pulleys and a stop motion including a belt shipper and a cushioned stop dog, the combination with said loose pulley and stop dog, of a worm fast to the loose pulley, a member normally disconnected from the worm, means controlled by the cushioning movement of the stopl dog to connect said member to the Worm, and a pull-off and thread cutter actuated by said member.

l0. In a sewing machine having a fast pulley, a loose pulley, a driving belt for said pulleys and a stop motionv including a belt shipper and a cushioned stop dog, the combination with said loose pulley and stop dog, of a worm fast to the loose pulley, a slidable member normally disconnected from said Worm, a clutch pin for connecting the member to the worm, a latch holding the clutch pin inoperative, means actuated by the cushioning movement of the sto-p dog to release the latch and a cutter actuated by said slidable member.

11. In a sewing machine having a fast pulley, a loose pulley, a driving belt for said pulleys and a stop motion including a belt shipper and a cushioned stop dog, the combination with said loose pulley and stop dog, 'of a worm fast to the loose pulley, a slidable member normally disconnected from said worm7 a clutch pin for connecting the member to the Worm, a latch holding the clutch pin inoperative, means actuated by the cushioning movement of the stop dog to release the latch and a thread .pull-off and cutter actuated by said slidable member.

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

JHN KIEWICZ.

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