US1739059A - Sewing machine - Google Patents

Description

A. F. CARLSON SEWING MACHINE Dec. 10, 1929.

Filed July 15, 192'? 4 Sheets-Sheet l & Y L" m uhw A mm W w mF m 4 Dec. 10, 1929. A. F. CARLSON SEWING MACHINE Filed July 15, 1927 4 Sheets-Sheet 2 Fig.2.

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Axel F Carlson by/ww Maw ATTys.

1929- v A. F. CARLSON 1,739,059

SEWING MACHINE Filed July 15, 1927 4 Sheets-Sheet 4 7 44 'lnv'ar flor. a Axel FfCqrlson YMMJ M ATrys.

Patented Dec. l d, 1929 PAT E NT FF l 111 1 nxnt r. canteen, on canrnnrnen, MnssAoi-iusn lrs, rissisivoa 'ro THE nnncn sermon HOLE MACHINE COMPANY, or nosron, MASSACHUSETTS, a conrona'rrcn' or MAINE SEWING MACHINE Application filed July 15, 1927.

This invention relates to sewing machines of the type adapted to perform a predetermined sewing operation and then come to rest, such for instance as a buttonhole sewing machine.

One of the objects of the invention is to provide a novel means for controlling the work clamps by which when the clamps are released they will first close onto the work under a light pressure and subsequently while in engagement with the work will be subjected to an increased pressure to firmly clamp the cloth in position.

in some sewing machines which are adapted to perform a predetermined sewing operation and then come to rest the work clamps are normally latched in open position when the machine is at rest to allow the work to be positioned and when the machine is started the clamps are released and are closed onto the work under the influence of a relatively heavy spring which is used for maintaining the work clamps in yielding engagement with the work during the sewing operation, but where this construction is employed the clamps are closed onto the work with a quick movement and if the work clamps are provided with thread cutting and holding devices the jar incident to the quick closing of the clamps is liable to disarrange the threadholding device sulliciently so that the needle thread held thereby is apt to be loosened or disengaged. if this happens then the first stitch of the group of stitches is likely to be imperfectly formed.

One of the objects of my present invention is to avoid this diliiculty by providing means whereby when the work clamps are released they will close onto the work with a gentle pressure thus eliminating any jar which will be likely to loosen the held end of thread and also avoid any possibility of injury to the work by a sudden impact of the work clamps thereon, and after the Work clamps have thus been closed with a gentle pressure they will while in position against the work be subjected to a heavier pressure sufficient to firmly holdthe work in position.

In order to illustrate my invention I have chosen to show it as it might be embodied in CIR ' mounted at 11 tothe clamp plates.

ber 10 carries a hold-down plate 46 which Serial No. 205,955.

a buttonhole sewing machine of the type shown in my co-pending applications, Serial No. 79,523, filed January 6th, 1926 and Serial No. 112,507, filed May 29th, 1026 and Serial No. 112,810, filed June 1, 1926. The invention, however, is applicable to other sewing machines and, therefore, is not limited in its useto the type of machine shown in the abovementioned applications.

In the drawings Fig. lis a side view of a sewing machine having my improvements applied thereto;

Fig. 2 is an enlarged top plan view of the work clamps;

Figs. 3 and i are fragmentary views illustrating the togglelever device for locking the work clamps in clamping position;

Figs. 5 and 6 are fragmentary views of the means for releasing the clamps and straightening the toggle, Fig. 5 showing the clamps released and Fig. 6 showing the toggle straightened Fig. 7 is a sectional view on the line 7-7,

.Fig. 5.

As stated above the sewing machine herein shown is of the general type illustrated in my co-pending applications Serial llos. 79,523, 112,507 and 112,810. This machine is provided with the frame 1 from which extends the overhanging arm 2 that carries the upper thread manipulating mechanism in the floral of the usual needle 3 that is mounted in a vertically reciprocating needle bar l, the latter having a lateral jogging movement during the sewing operation asusual in sewing machines of this type.

The frame 1 has extending therefrom a work supporting arm 5 on which the work 6 is supported, this arm carrying the under thread manipulating mechanism which n be of any approved type but is not herein illustrated. The work 6 is supported on clamp plates 7 and is clamped in position against the plates by means of work clamps 8 all as usual in sewing machines of this type. The work clamps 8 are carried by clamp arms 9 which are pivoted to and extend forwardly from a rocking memberlO that is pivotally The memthe needle thread is cut and the cut end is held. This comprises a thread cutter 12 of the general type shown in my co-pending application Ser. No. 112,810, filed June 1, 1926 and which is carried by an arm 13 pivotally secured to one of the clamp arms 9, and a thread holder 14 carried by an arm 15 adapted to engage and hold the cut end of the thread. I i

The devices for actuating the thread cutter are or may be all as usual in the above-mentioned applications andform no part of my present invention. In the devices of said prior applications the clamp arms 9 are acted on by a spring of considerable strength so that when the clamps are released at the beginning of the sewing operation they are forced down against the Work with a quick blow. The jar incident to this blow is apt to dislodge the held end of the thread from the thread'holder and furthermore the force with which the work clamps come against the work is sometimes apt to injure delicate faloric. Accordingly, as stated above, the principal object of the present invention is to provide a work clamp operating means so constructed that when. the work clamps are released they will close against the work with a gentle movement after which the required clamping pressure will be applied.

Theclamps are held open when the machine has been brought to rest by means of a latch 16 all as shown in my above-mentioned applications, this latch having latching engagement with a projection 17 carried by a lever arm 18 thatis rigid with a rock shaft 19. The rock shaft 19 is connected to a toggle lever device by which the clamps are opened and closed. This rock shaft is journalled in bearingsi44 carried by the clamp plates 7 and; has at one end an upstanding arm'20 that is pivotally connected to the central joint of a toggle lever device comprising the two toggle elements 21, 22. These toggle elements are pivotally connected at'23 and the pivotal pin extends inwardly into a slot 24 formed in the upper end of the arm 20.

The toggle member 22 is pivotally connected to theroeking member 10, the latter having two ears 25 between which the lower end of the toggle member 22 is received, said member 22 being pivotally connected to the ears through the pivotal pin 45.

The upper end of the toggle member 21 is pivoted to a stand or bracket 27 which rises from the clamp plate 7. Since the upper end of the toggle device 21, 22 has a fixed pivot it follows that when the toggle device is straightened the lower end thereof will be forced downwardly thereby rocking the member. 10 and lowering the clamps, while when the toggle lever is broken the lower end will be raised thereby raising the clamps. The lever member 18 is provided with a handle 28 by which it may be manually operated to raise or lower the clamps.

Means are provided whereby when the machine is to be started the latch 16 will lirst he released thereby allowing the work clamps to close onto the work with a gentle movement, and immediately thereafter the toggle lever 21, 22 is straightened and a relatively heavy pressure is applied to the work clamps.

The means herein shown for releasing the latch 16 is similar to that illustrated in the co-pending applications. This release is effected through a lever 29 pivoted to the bed at. 30 and provided with a roll 31 adapted to engage a cam surface 32 on the under side of the latch 16. hen the lever is swung anti-clockwise Fig. 1 the engagement of the roll 81 *ith the surface 32 will raise the latch and disengage it from the lug 17. The lower end of the lever 29 is connected by a link 33 to one arm of an elbow lever 34 pivoted to the frame at 35. The other arm of said elbow lever has a link connection 36 depending therefrom which extends through a head 31'' that is connected by a link 38 to a starting treadle or starting device. lVhen the link 38 and head 37 are depressed the latter will en gage a collar 39 on the link 36 and thereby rock the lever 34 and swing the lever 29 into a position to release the latch 16 as shown in Fig. 5. The movement of the head 37 also functions to set the stitch-forming mechanism in operation all as shown in the abovementioned applications.

The stitch-forming mechanism is actuated from a shaft 41 which is driven by a driving pulley 40, a suitable clutch (not shown) being employed for connecting the pulley to the shaft. The means for actuating the clutch comprises a link or connection 42 which or:- tends through an opening in the head 37 and is providedwith a collar 43 thereon so situated that when the head 37 is moved downwardly it will engage the collar 43 thus drawing downwardly on the connection 42 and throwing the clutch into operation all as described in the above-mentioned applications.

The collar 48 is so adjusted relative to the collar 39 as to allow a certain amount of lost motion between it and the head 37 so that when the head 37 is moved downwardly the initial movement will actuate the lever 29 and release the latch 16 and further movement will actuate the connection 42 and thus throw the clutch into operation, the purpose of this arrangement being to ensure that the clamps will be closed before the machine is started.

The arrangement is such that the first or initial movement of the connection 33 will release the latch and further movement will straighten the toggle 21, 22 thus locking the clamps against the Work, and will also actuate the member 42 and set the machine in operation.

its a means for straightening the toggle lever 21, 22 l have provided a latch member t7 which is pivotally connected to the lower end of the lever 29 as shown at 52, said latch member having a cam slot therein in which is received a fixed pin 51 carried by the arm 5. The end oi the latch 47 is provided with a head 18 which is adapted to engage the lower end l9 of the lever 18 and thus swing the lever from the position shown in F 5 to that shown in Fig. 6. Since this lever 18 is rigid with the shaft 19 the swinging movement of the lever will turn the shaft 19 and thus swing the arm 20, which, it will be remembered, is connected to the central joint of the toggle 21, 22. The swinging of the lever 18 and arm 20, therefore, straightens the toggle device 21, 22 and in fact carries the center pin 23 of the toggle slightly beyond the cen ter. This straightening ot' the toggle locks the two clamps in closed position under relatively heavy pressure.

Fig. 1 shows the parts in normal position when the machine comes to rest. When the machine is to be started the initial downward movement of the connection 38 and head 37 will rock the elbow lever 34: and thus give a backward movement to the connection 33. The initial backward movement of the connection 33 will swing the lever 29 and thus raise the latch 16 and disengage it from the lug 17 as shown in Fig. 5. This allows the work clamps to drop onto the work with a light pressure under the influence of gravity and the downward movement of the work clamps partially straightens the toggle lever 21, 22 as illustrated in Fig. 0. The continued movement of the connection 33 and the latch 47 brings the cam portion of the slot 50 into engagement with the fixed pin 51 and as said cam portion passes over the pin the latch 47 will he raised into the position shown in 5 thus bringing the end l8 thereof into position to engage the lower end 49 of the lever 18. During further backward movement of the connection 33 and the latch 47 the lever 18 is acted on and turned from the position shown in Fig. 5 to that shown in Fig.

6. Eince the lever 18 is fast on the rock shaft 19 which has the arm 20 rigid therewith the turning movement of the lever will operate through the arm 20 and pin 23 to completely straighten the toggle 21, 22 and in fact to carry the center pin 23 ofthe toggle slightly by the center thereby locking the toggle in its straightened posit-ion. The straightening of the toggle operates to apply a relatively heavy pressure to the work clamps which is maintained during the sewing operation by the fact that the tole has been sh gl'tened and carried slightly past its Just as the toggle isbeing straightened the clutch is thrown into engagement to start the stitch-forming mechanism, this being accomplished as stated above by the downward movement of the link 42 due to the engagement oi the link 37 with the collar 43. filter the sewing machine has started the pressure on the treadle or starting mechanism is released so that the connection and head 37 are raised into their upper position and as this occurs: the spring 53 returns the lever 2; to its normal position and thereby moves the latch 17 forwardly into the position shown in Fig. 1, in which position the head 4C8 has been moved below the end 49 ofthe lever 18 by rem son of the cam slot 50. This return move" ment of the lever 29 allows the latch 16 to move downwardly and when the machine has completed its operation and has come to rest said latch 16 is given a forward movement sufficient to enable it to hook over the lug 17 and is then given a rearward movement to swing the lever 18 from the posi -on shown in Fig. 6 to that shown in 1 thereby open ing the clamps all as shown in the abovementioned applications.

While it have illustrated herein selected embodiment of my invention 1 do not wish to belimited to the constructional features shown.

I claim:

1. ln a sewing machine, the combination with work clamps, means normally holding the work clamps raised, means to release the work clamps, said clamps when released automatically moving into clamping position but engaging the work with a gentle pressure, and means operative after the work clamps have closed onto the work to apply a relative- 1y heavy pressure thereto.

2. ln a buttonhole sewing machine, the combination with work clamps, of a latch for normally holdin the work clamps raised, means to release the latch and thereby permit the work clamps to close onto the work with a gentle pressure, and means to subject the work clamps thereafter to a relatively heavy pressure.

3. In a sewing machine, the combination with work clamps, of a latch for holding the work clamps raised, a toggle lever device connected to the work clamps and which when straightened closes the clamps onto the work under relatively heavy pressure, means to release the latch thereby allowing the clamps to close onto the work with a gentle pressure, and means acting subsequently to straighten the toggle, and thus apply relatively heavy pressure to the clamps.

4. In a sewing machine, the combination with work clamps which normally tend to close onto the work with a gentle pressure, of means holding the work clamps raised, a movable actuating member and means operative on initial movement oi said member to ill release the clamps thereby permitting them automatically to close onto the work with a gentle pressure and upon further movement to apply relatively heavy pressure to said clamps.

5. In a sewing machine, the combination with work clamps, of a latch normally holding the clamps raised, a movable actuating member, means operative upon the initial movement of said member to release the latch thereby permitting the clamps to close onto the work under a gentle pressure and upon further movement of said actuating member to apply relatively heavy pressure to said clamps.

6. In a sewing machine, the combination with work clamps, of a latch for holding the work clamps raised, a toggle lever device connected to the work clamps and which when straightened closes the clamps onto the work undera relatively heavy pressure, a movable actuating member, and means operative upon the initial movement of said member to release the latch thereby allowing the clamps to close onto the Workunder a gentle pressure and upon further movement of said actuating member to straighten the toggle and thereby apply heavy pressure to said clamps. In testimony whereof, I have signed my name to this specification.

AXEL F. OARLSON.

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