US1218107A

US1218107A - Thread-cutting device for buttonhole-sewing machines.

Info

Publication number: US1218107A
Application number: US2929015A
Authority: US
Inventors: Richard Mundlos
Original assignee: Mundlos & Co H
Current assignee: H Mundlos & Co; Mundlos & Co H
Priority date: 1915-05-20
Filing date: 1915-05-20
Publication date: 1917-03-06
Anticipated expiration: 1934-03-06

Description

R. MUNDLOS.

THREAD CUTTING DEVICE FOR BUTTONHOLE SEWING MACHINE-S.

Patented Mar. 6, 1917.

2 SHEE-SHEET I.

APPLICATION FILED MAY 20, 19,15.

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R. MUNDLOS.

THREAD CUTTING DEVICE FOR BUTTONHOLE SEWING MACHINES.

APPLICATION FILED MAY 20, i915.

' Patented Mar. 6, 1917.

2 SHEETS-SHEET 2.

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THREAD-CUTTING DEvIoEV Een BUrronnoLE-snwnve' ivraonINEs.

Specification of Lettersilatent.

Patent-canal. c, i917.

Application filed May 20, 1915. vSerial No. 29,290.

Thread-Cutting Devices for Buttonhole- Sewing Machines, of which the following is a specification. l

My invention relates to a thread cutting device or mechanism for sewing machines and particularly of a kind adapted for use in button hole sewing machines.

The object of my invention is to provide a thread cutting mechanism by whichrthe two threads in the machine, that is the upper thread and the lower thread, Vare simultaneously cut when the machine is at rest.

My invention is shown in the accompanying drawings wherein:

Figure 1 is a side view of the parts of a button hole sewing machine embodying the invention.

Fig. 2 is a plan of the same.

Fig. 3 is a partly sectional view of a part of the mechanism for cutting` the upper thread and the lower thread on alarger scale showing the parts in the position during the from the sewing plate 12 orthe work cutting operation.

Fig. 4 is a view ofthe mechanism for cutting the lower thread on a larger scale.

The devices for cutting l voff the upper thread and the lower thread or the upper cutting device and the lower cutting device are held. in operative interdependence by the presser member so that the two devices simultaneously begin the cutting operation. The presser member is formed at itsvforeend soas to act like the so-called presserfoot and carries at this end the detachable blade or cutter 2 for cutting the upper thread. Said cutter 2 is of angular shape and can be easily detached from its carrier, e. g. for grinding purposes, and again attached thereto without the necessity of removing any other partsfrom their operative positions. The presser member comprises two levers or parts 1a and 1b mounted on hinges 3 and 4 respectively, the partlb being free to turn on its hinge 4 to a certain extent independently of the part 1a, the two parts being turned together about the hinge 8 for the purpose of lifting the presser foot (fabric or. the like) thereon. rhis turning or oscillating movement of the presser member is effected by means of atreadle (not shown) and a member (not shown) vsuch as a rod or chain connectingv thetreadle with the vpart 1" as is well understood-by those skilledin the art.` ln actuating the treadle the part 1b is first turned downward alone about 4, thereby acting upon an angle y shaped .plate adjustably mounted Von a slotted lever 5 having its fulcrum at 7 and being directly connected with the actuating Y rod 8 of the lower cutting device which is controlled by a spring. 1'1, by means of a pin 10 engaging the slot 9 of the lever 5. The said rod 8 is atvthe other end, connected with the arm 1421 of a lever 14 having its fulcrum at 13 below the sewing plate 12 and engaging, with its forked arm 141?, the pin loflthe lever lil-operating the blade or cutter 15 for cutting the lower thread. The cutter 16 is connected with the arm 17 of the lever 19 having its fulcrum at 15. The

lever arm 17. serves the special .purpose of vpulling oi'lthe lower thread and the lever 14 is controlled by aspring 20. By the action of the part 1b ofthe presser Ymember on theplate 6 of the slotted lever 5 the latter is turnedV aboutits fulcrum 7 so that the rod Y 8 engaging. thefslot 9 of the lever 5 by means of its-pin 410, .is longitudinally moved forward against the action of its spring 11 and thereby the lever 14, the cutter 16 and the thread pulling arm 17 are simultaneously actuated. 1n turning the lever 5 downward from its normal position the plate 6 acts upon a lever 22 fulcrumed at 21 and controlled by aspring 23, so that the lever 22 rotates against the actiony of its spring 23 whichholds the lever 22 at all times in conf tact with the plate 6 and alsocauses the lever 22 to return to its normal position when the lever 5 reassumes its normal position. In starting the sewing machine the presser member moves forward, as usually infmachines of this kind, so that the lever 22 at the ytime will not be in contact with the rod 2,4, engaging only the adjustable plate 6 of the lever 5. At the backward movement of the presser member the said rod bearsiagainst theVfore-arm of the lever- 22 and is held underpressure by the action of its spring 26; thus the rod 24 is moved forward with relation to the presser member Vby the arm or-lever 27, so as to pass by the blade or cutter 2 for the upper thread and cause the latter to be cut on".

lThe angular end 25 of the lever 22 forms a separate part and can be adjusted with relation to the lever by means of a screw and nut 3l in a longitudinal slot 30 of the lever 25. In order to not actuate the cutting off before the machine is stopped a cam lever 33 is connected with the disengaging member 32 of the machine drive, said lever 33 assuming, as long as the machine is working, a position below the angular plate 6 of the lever 5 so as to lock the latter and the presser member la lb and thus prevent the cutting devices for the upper and the lower thread from operating. The cam lever 33 is so shaped or fashioned as to be adapted to prevent the machine from being engaged or coupled and started so long as the presser member la all is open or lifted and at the same time to assist in the lifting of the slotted lever V5. The said cam lever 33 has its fulcrum at 34 and is connected with the disengaging member 32 of the machine by the arm 35 andthe Vlink 3G, lever 37 and link 38. The lever 37 is fulerumed at 39.V As soon as the machine is stopped by means of the disengaging mechanism, the cam lever 33 releases the lever 5 and the angular piece 6 attached thereto so that the presser member la lb is free to turn or oscillate and the thread cutting devices can be actuated simultaneously by the movement of the slotted lever 5, 6 and the locking lever 22 in the manner aforedescribed.

As soon as the part lb of the presser member is actuated to operate the levers 5 and 22 and has finished part of its way a pin 40 adjustably mounted at the lower face of the said part lb begins to act on the back end of the part la of the presser member to turn said part lfL about its pivot 3 so that the foreend of the part la is lifted from the machine plate or the fabric thereon. 0n releasing the treadle and the part lb connected therewith the presser member is returned to its initial or normal position by means of springs 4l and 42, the former being mounted between the superposed ends of the two Y parts lEL lb of the presser member, the latter acting on the fore-'end of the part la. At the same time the cam lever 5 is returned to its initial position by means of a link or chain 43 connecting said lever with the part lb of the presser member.

The rod 24 is moved forward owing to the backward movement of the presser member whereby the thread pulling member 29 rotatably mount-ed on the vertical rod 28, is turned by the lever 27 into the proper operating position. The thread pulling member 29 is provided on its upper face with ribs or teeth which act to hold the thread and draw same back again-so that the thread never can be caught.

As regards the operation of the cutter 16 it is to be noted, that the lower thread comes from the bobbinl in 'the bobbincase or boX and passes through the vertical hole in the stitching-plate to the work. As the cutting device is being operated the Ylever arm 17 pulls off the thread from the bobbin, but said lever arm 27 never can pull the thread out of the range of movement of the cutter lf3, since the thread passes through the hole in the stitching plate and the cutter moves close by said hole.

What l' claim is:

l. ln a button-hole sewing machine, a presser member fulcrumed to the machineplate, a device for cutting off the upper thread, a device for cutting olf the lower thread, a rod, 24, adapted to actuate the former, and a rod, 8, adapted to actuate the latter, a lever, 5, in operative connection with the said rod, 8, and in engagement with the presser member, and a lever, 22, in engagement with the other rod, 24, and with thev other lever, 5, to be moved simultaneously therewith.

2. In a button-hole sewing machine, a presser member fulcrumed to the machineplate, a device for cutting ofi1 the upper thread, a device for cutting oifthe lower thread, a rod, 24, adapted to aetuate'the former and a rod, 8, adapted to actuate the latf:

ter, a lever, 5, in operative connection with the said rod, 8, and in engagement with the presser member, a lever 22 in engagement with the rod, 24, and the lever, 5, and an adjustable angular end piece, V25, on said lever, 22, adapted to bear against the cutter actuating rod, 24.

3, In a button-hole sewing machine, a presser member fulcrumed to the machineplate, a device for cutting Voff the upper thread, a device for cutting oli' the lower thread, a rod, 24, adapted to actuate the former and a rod, 8, adapted to actuate the latter, a lever, 5, inoperative connection with the said rod, 8, and in engagement with the presser member, a lever, 22, a cam lever, 33, a member, 32, for disengaging the machine drive, and intermediate means con- `necting said cam lever with the said member, 32, all the parts constructed and arranged so that the aforesaid levers, 5 and 22, are locked when the machine drive is engaged. Y

4. In a. button-hole sewing machine, a

presser member fulcrumed to the machineplate, a device for cutting off the upper thread, a device for cutting off the lower thread, a rod, 24, adapted to actuate 'the former and a rod, 8, adapted to actuate the latter, a lever, 5, in operative connection with the said rod, 8, and in engagement withV the presser member, a lever, 22, a cam lever, 33, so shaped or profiled as to prevent`the machine from being engaged or coupled to start when the presser member is lifted or open, and to assist in lifting the lever 5, a member 32, for disengaging the machine drive, and intermediate means connecting said cam lever with the said member 32.

5. In a button-hole sewing machine, a presser member fulcrumed to the machine plate, a device for cutting off the upper thread, a device for cutting off the lower thread, a rod, 24, adapted to actuate the former, and a rod, 8, adapted to actuate the latter, a lever, 5, in operative 'connection with the said rod, 8, and in engagement with the presser inember comprising two superposed parts or levers, the one, la, being fulcrumed to the machine plate, the other, 1b, being fulcrumed on the former, so as to act, when actuated, irst on the said lever, 5, alone, and thereafter on the part, 1a, for the purpose of operating same.

6. In a button-hole sewing machine, a presser member fulcrumed to the machine plate, a device for cutting off the upper thread, a device for cutting off the lower thread, a rod, 24, adapted to actuate the former, and a rod, 8, adapted to actuate the latter, a lever, 5, in operative connection with the said rod, 8, and in engagement with the presser member comprising two superposed parts or levers, la, 1b, and two springs 42, 41, acting on said levers same from being retained, a rod, 24, adapted to actuate both the said cutter and the said member, 29, a device for cutting oftl the lower thread, a rod, 8, adapted to actuate the latter, a lever, 5, in operative connection with the said rod, 8, and in engagement with the presser member, and av lever, 22, in engagement with the other rod, 24, and with the other lever, 5, to be moved simultaneously therewith.

8. In a butt-on-hole sewing machine, a presser member fulcrumed to the machineplate, a device for cutting off the upper thread, an actuating rod, 24, a blade or cutter, 16, for cutting o the lower thread, a thread pulling member, 17, both the latter andthe said cutterl being connected to rotate about the same pivot 15, an actuating rod, 8, a lever, 5, in operative connection with the said rod, 8, and in engagement with the presser member, and a lever, 22, in engagement with the other rod, 24, and with the other lever, 5, to be moved simultaneously therewith.

' In testimony whereof I have afiXed my signature in presence of twowitnesses.

L. OCHLMANN, A. REILLY.

Copies of this patent may be obtained for ve cents each, by addressing the Commissioner of Patents,

Washington, D. C.