US2539627A

US2539627A - Control mechanism for sewing machines

Info

Publication number: US2539627A
Application number: US121608A
Authority: US
Inventors: Harold V Kindseth; Jr Jean E Zeller
Original assignee: Bemis Brothers Bag Co
Current assignee: Bemis Brothers Bag Co
Priority date: 1949-10-15
Filing date: 1949-10-15
Publication date: 1951-01-30
Anticipated expiration: 1968-01-30

Description

1951 H. v. KlNDSETH ET AL 2,539,627

CONTROL MECHANISM FOR SEWING MACHINES 3 Sheets-Sheet 1 Filed Oct. 15, 1949 Jan. 30, 1951 H. V. KINDSETH ET AL CONTROL MECHANISM FOR SEWING MACHINES 3 Sheets-Sheet 2 'IIIIIIIIlI/lllln:

Filed Oct. 15, 1949 Jan. 30, 1951 H. v. KINDSETH ET AL CONTROL MECHANISM FOR SEWING MACHINES Filed Oct. 15, 1949 3 Sheets-Sheet 3 Patented Jan. 30, 1951 UNITED STATES 'ATENT OFFICE GONTR-OL MECHANISM FOR SEWING MACHINES Application October 15, 1949, Serial No. 121,608

(Cl. ll ll) 12 Claims.

Our invention relates broadly to power-driven sewing machines and, more particularly, to machines which are adapted for stitching articles successively fed in spaced relation.

Still more specifically, our invention relates to sewing machines which are adapted to stitch together the normally open upper ends of filled bags. In such devices, it is common practice to utilize and sew through one or more continuous strips of tape. The tape is secured to one or both sides of the bag adjacent the upper edge, and provides reinforcement for the closure thereof and tends to prevent the escape from the ba of fine granular material which might otherwise escape through the stitching alone.

Heretofore, in machines of this type, means has been provided for automatically cutting the tape responsive to movements of the bag in its path of travel through the sewing machine, to cut the tape adjacent the opposite side edges of the bag. However, the means for feeding the tape and actuating the sewing mechanism has heretofore usually been manually controlled. Therefore, there has inevitably been a considerable loss of both tape and thread if, for one reason or another, the operator either fails to continuously feed the bags (or other articles to be stitched) in close succession or fails to stop the sewing and tape-feeding mechanism during periods which elapse between relatively widely-spaced articles.

The object of our invention is the provision of 2:

novel means whereby the sewing and feeding movements are automatically initiated and terminated by mechanism responsive to the movements of the bags or other articles being run therethrough.

Another object of our invention is the provision of common control means for successively initiating a sewing and tape feedin operation respectively, and thereafter imparting cutting movements to the cutter means whereby to cut the tape on opposite edges of the bag.

A still further object of our invention is the provision of a device of the class described in which the common control means is provided with a plurality of successively-arranged. camacting steps, whereby to successively initiate and terminate feeding and sewing movements cutting movements to the tape.

The above and still further important objects and advantages of our invention will become apparent from the following detail specification, appended claims and attached drawings.

Referring to the drawings, in which like characters indicate like parts throughout the several views:

Fig. 1 is a fragmentary view in side elevation, with some parts broken away and some parts shown in section, of a power-driven sewing machine and controls therefor built in accordance with our invention;

Fig. 2 is a fragmentary view partly in front elevation and partly in section seen from the line 2--2 of Fig. 1;

Fig. 3 is a horizontal section taken substantially on the line 3-3 of Fig. 2;

Fig. 4 is a view corresponding to Fig. 3, but showing a different position of some of the parts;

Fig. 5 is a View corresponding to Fig. 3, but showing still another position of some of the parts thereof;

Fig. 6 is a vertical section taken substantially on the line 6i5 of Fig. 2; and

Fig. 7 is a diagrammatic view of a form of control switch of my invention.

Referring with greater particularity to the drawings, the numeral 8 indicates in its entirety, a power-driven sewing machine having a base 2 and a sewing head 3. The head 3 supports a needle 4 by means of a conventional reciprocating needle bar 5 and a presser foot 6 secured to the inner end of a presser bar l. The Sewing and feeding mechanism of the machine is of conventional nature and is shown in the drawings more or less diagrammatically. However,- it will be seen, by reference to Figs. 1 and 3 to 5, inclusive, that the needle bar 5 and feeding mechanism are driven from a drive shaft 8, the needle bar 5 being operatively connected thereto by gearing 9, a rotary shaft l0, and crank and pitman connections H. The feedin mechanism comprises an eccentric l2 fast on the drive shaft 8, a pitman arm 13 driven by the eccentric l2 and connected at its free end to a crank arm l4 fast on a rock shaft 15. The rock shaft I5 is suitably journaled in the base 2 and has rigidly secured thereto a crank arm H5 which drives a pair of feed dogs I! and i8 through a rigid link IS. The feed dogs H and I8 extend laterally outwardly through an aperture 20 in a base plate 2 l, shown as being part of the base 2. The feed dogs I! and 18 are adapted to move in a direction to feed material between the base plate 2! and the presser foot 6 from the right to the left with respect to Figs. 3 to 5, inclusive.

The frame i of the sewing machine is rigidly secured to a mounting bracket 22 which is supported from a main supporting frame 23 by later!- ally extending arms 24, one of which is shown. A drive motor 25 is rigidly secured to the upper end of the bracket 22 and drives the sewing and feedin mechanism through a V-belt 26 running .over a V-pulley 21 on the shaft of the motor 25 and another V-pulley 28 mounted fast on the drive shaft 8.

It will be seen, by reference to Fig. 1, that the pulley 2? is provided with a clutch mechanism 29 which is operated by a clutch lever 30 to operatively couple the pulley 2? to the motor 25. The clutch lever 36 is pivoted intermediate its ends to an arm 3i secured to the base of the motor 25. At its free end, the lever is secured by a coupling 32 to a plunger 33 operated by a solenoid, shown by dotted lines in Fig. 1 and indicated by the numeral 34. The solenoid 34 is contained within a housing 35 secured to the base of the motor 25 and supported by the upper end of the bracket 22. The lever 39 is further provided with cushioning springs 36 and an adjustable stop element 37. The clutch and operating linkage therefor do not in themselves constitute the invention and further detailed description thereof is deemed unnecessary.

The clutch-operating solenoid 34 is controlled by a switch 38 contained within a housing 39 mounted on the base plate 2i. The switch 33 is one of the type permitting overtravel of the switch actuator after the contacts of the switch have been closed. A plunger-type switch button M! is provided with a cam element A! which engages a co-operating cam element 62 on the free end of a contact-equipped leaf spring 43. inward movement of the button 40 causes the cam element d! to engage the cam element 42 to move the contact of the leaf spring 43 into engagement with the co-operating contact mounted on a co-operating leaf spring switch element 44.

After contact has been made, the cam element 4! is free to move downwardly beyond the cam element ii and in frictional engagement with the leaf spring 43. A coil compression spring 45 biases the switch button 413 in a direction to sewing together of opposite sides of the upper end of filled bags, it is sometimes expedient to apply reinforcing tape to the upper ends of said bags and cause the stitching to extend through said tape or tapes. This arrangement aids in sealing the bags, particularly when the bags are filled with fine granular or powdered material which would otherwise tend to escape between the stitching. A filled bag is indicated in the drawings by A, the upper closed end B thereof adapted to be fed through the machine between strips of tape T. The tape T, which may be 'made from any suitable material such as paper, fabric or the like, is fed into the machine between the base plate 2! and the presser foot 6 through feeding guides 50, which are shown fragmentarily in Figs. 2 to 5, inclusive, and which are conventional in nature. The tapes T are 'fed through the machine in a direction from the right to the left with respect to Figs. 3 to 5, in-

clusive, by the tooth-equipped feed dogs i1 and l 8 and the closed ends 13 of the bags A are initially fed therebetween either manually or by mechanical means, as desired.

It is preferred that a short length of sewed tape extend laterally outwardly from each side edge of the closed bags A to prevent the stitching therein from becoming loosened or unraveled within the limits of the bag, thereby causing leakage. We provide cutting means for severing the stitching and the tape T at predetermined distances from the opposite side edges of the bags A, said cutting means comprising a relatively stationary cutter blade 5! and a relatively movable cutter blade 52. The stationary cutter blade 5! extends outwardly into the aperture 25 of the base plate 2! intermediate the feed dogs I! and I8 and is rigidly secured to the base 2 (see Fig. 6). The movable cutter blade 52 is adapted to co-operate with the stationary cutter blade 5! through a recess or notch 53 in the presser foot (5. Mechanism for operating the cutter blade 52 may be of any conventional type such as disclosed in the Sauer Patent- No. 2,229,997.. A preferred form of mechanism for operating the cutter blade s2 is, however, illustrated in Figs. 2 and 6 as comprising an arm 5:3, to the outer end of which the cutter blade 52 is rigidly secured, and mechanism for moving said arm a direction to cause cutting engagement between the cutter blades 52 and 5!. The arm as is journaled at one end on a tubular shaft 55 which is mounted between upstanding supports it and 5'! formed integrally with the base 2, and is yieldingiy biased in a direction to move the cutter blade 52 out of engagement with the cutter blade 5! and out of the path of travel of the tapes T and the upper end B of the bag A by a torsion spring 53. The journaled end of the arm E4- is provided at one side with ratchet teeth that are adapted to engage co-operating teeth on a crank arm as which is also journaled on the tubular shaft 55 adjacent the arm 54. The free end of the crank arm 59 is pivotally connected to a pitman 50, the inner end of which is secured to an eccentric it! mounted on the drive shaft 8. The crank arm 59 is oscillated continuously during the sewing and feeding operation of the sewing machine and the ratchet teeth of the crank arm 59 are normally maintained out of engagement with the ratchet teeth of the cutter blade arm 54 by a coil compression spring 52 encircling the tubular shaft 55 intermediate the journaled ends of the

arms

54 and 59. In order to cause the cutter blade 52 to sever the tape T and stitching therein, it is necessary for the ratchet teeth on the oscillating arm 5%} to engage the co-operating ratchet teeth on the cutter blade arm 54 for a time interval necessary to produce a single cutting movement of the cutter blade 52. For this purpose, there is provided a collar 63 mounted for axial sliding movements on the tubular shaft 55 adjacent the side of the crank arm 59 opposite the ratchet teeth thereon. The collar 63 is held against rotation on the shaft 55 by a key-acting screw or the like 64 which has its inner end contained in a keyway 55 in the tubular shaft 55. A thrust washer 65 is interposed between the collar 63 and the journaled end of the crank arm 59. The collar 63 is provided with a cam-acting lug 6i which is adapted to be engaged by a similar lug 68 on a crank-acting member as which has its inner end journaled on the tubular shaft 55 adjacent the upstanding support 56. It will be seen, by reference to Figs. 2 and 6, that movement of the member 59 in a clockwise direction, in respect to Fig. 6, will cause the cam lug it to engage the cam lug Si and move the collar 63 and crank arm 59 toward the ratchet teeth on the cutter arm 54 against bias of the spring 62. Continued movement of the member 69 causes the cam lug 68 to move beyond the cam lug 6i and permits the spring 82 to move the ratchet teeth on the crank arm 59 out of engagement with the teeth on the cutter blade arm 54. Of course, during the time that the ratchet teeth are engaged, the crank arm 59 will impart a swinging movement to the cutter blade 52 to sever the tape. Similarly, when the member 69 is moved in a counterclockwise direction, with respect to Fig. 6, to its normal position shown therein, engagement of the cam lugs 68 with the cam lug 6'! will cause the ratchet teeth to engage and another cutting operation to be performed. The member 69 is yieldingly biased in one direction by a coil tension spring it which has one end anchored thereto and the other end anchored to the base plate 2|.

An operating arm H for the switch 38 has a shaft 12 rigidly secured to its intermediate portion. The shaft '52 is journaled in the tubular shaft 55 and is held against axial movement by a washer '53 which engages one end of the tubular shaft 55 and which is held securely in place on the end of the shaft l2 by a machine screw or the like is. As indicated in Figs. 1 and 2, one end of the arm ll overlies and engages the outer end of the switch button 49, the other end thereof having an angular portion l5 which overlies the outer end of the member 69.

The primary feature of our invention is an arrangement whereby, when a bag or article to be sewed is moved between the base plate 2| and the presser foot 6, the sewing and tape-feeding operations will automatically function, the tape T severed at a predetermined spaced distance from one side edge of the bag A, and thereafter, when the upper end of the bag has been stitched closed, the tape T and stitching will be severed at a predetermined spaced point outwardly of the opposite side edge of the bag and the feeding and sewing operations terminated. To achieve these results, we provide a control member in the nature of a laterally movable finger 16, extending longitudinally of the path of travel of the tapes T and the bag A and located laterally of the presser foot 8 at a point where at least a portion hereof intersects the path of travel of the upper end portion B of the bag A. At its rear or trailing end, the control finger l6 has a laterally outwardly projecting portion ll which is secured fast to the outer end of the member 69. Between the end El and its intermediate portion, the control finger i6 is offset to provide a step 18, the purpose of which will hereinafter become apparent. The forward or leading end of the control finger 75 is laterally outwardly offset from the intermediate portion thereof to provide a step is, the connecting portion between the step #9 and the intermediate portion of the finger 16 providing a cam surface Be. At its extreme leading end, the step portion 19 is curved laterally outwardly to provide acam surface M. The free end of the angularly offset portion of the switch-operating arm ll is provided with a screwthreaded opening which receives a stud 82 having an enlarged head 83 which is adapted to engage the extreme outer end of the laterally projected ii. The screw-threaded engagement of the stud 82 with the member it enables the arm H to be adjusted so that there is no lost motion between its opposite ends and the switch button so and the end portion 1'! of the control finger L3. It will also be noted that the intermediate portion. of the control finger l6 normally lies in a groove or channel 84 in the base plate 2|. In the normal position of the control finger 16, the step 19 is disposed substantially at the same level as the outer surface of the base plate 2!.

When it is desired to close and stitch a filled bag A, the upper end portions of the bag are moved together, as indicated in Figs. 1 and 3 to 5, inclusive. Assuming that the motor 25 is in oper-- ation, the bag A is then moved in a direction from the right to the left with respect to Figs. 3 to 5, inclusive, the closed portion B thereof engaging the cam surface 8| of the control finger l6. Continued movement of the bag A causes the control finger 18 to be moved laterally out-- wardly to the position indicated in Fig. 4, wherein the top portion B of the bag A lies between the step 19 and the base plate 2 l. Movement-of the control finger to the position of Fig. 4 causes the swtich-operating arm H to be swung on the axis of its shaft 12 to close the switch '38. Closing of switch 38 energizes the solenoid 34, whereby to cause the clutch 29 to bring the pulley 21 into operative engagement with the shaft of the motor 25. The sewing and feeding mechanism stitches and feeds the tapes T and moves the same toward the left with respect to Figs. 3 to 5, inclusive. As the bag A continues to be fed to the left, the upper end B of the bag A is stitched between the tapes T. Movement of the bag A during stitching and feeding operation causes the upper portion B of the bag to engage the cam surface 80 of the control finger l6 and moves the intermediate portion thereof out of the channel 84 to the position shown in Fig. 5. During the laterally outwardly travel of the control finger 16, the member 69' is moved thereby to and beyond the point where the cam lug 68 engages and runs over the cooperating cam lug 61. As above described, this momentary engagement of the cam lug 68 with the lug 61 causes the cutter blade 52 to sever the tapes T and stitching therein at a point laterally outwardly of the side edges of the bag A. As soon as the cam lug 68 has passed beyond the cam lug 61, the torsion spring 58 moves the cutter 52 to its normal position of Figs. 3 and l, and the upper end B of the bag A and the tapes T are allowed to be fed thereby. When the entire width of the bag has been stitched, and the opposite side of the bag passes the rear end of the intermediate portion of the control finger l6, coil tension spring 10 moves the member 69 in a direction to bring the control finger 16 toward its normal position. When this occurs, the step 18, which is at a common level with the step l9, will engage the portion B of the bag A for a short interval of time. This inward movement of the control finger 16 causes the cam lug 63' to move over the cam lug 61 in the opposite direction and again causes the cutter blade 52 to execute another cutting operation laterally outwardly of the opposite side edge of the bag A. Then, when the bag A has progressed beyond the step 18, the control finger 16 is permitted to return to its normal position of Fig. 3 under bias of the spring Hi. This last mentioned inward movement of the finger it permits the switch 38 to be opened, whereby to de-energize the sole noid coil 34 and disengage the clutch 29, thereby arresting stitching and feeding movements of the sewing machine.

With this arrangement, we have been able to effect a great saving in tape and thread, particularly when there is an appreciable time inte'ryal between the feeding of separate bags of material through the machine, and manual starting and Our invention has been tested on a commercial basis and found to be entirely adequate for the accomplishment of the objectives set forth, and while we have shown a single embodiment of our device, it will be understood that the same is capable of modification Without departure from the spirit and scope of the invention as defined in the claims.

What we claim is:

1. In a sewing machine, means for stitching articles successively fed in spaced relation, said means including a base plate and a sewing head, said head having a presser foot and cooperating needle, means for feeding a continuous strip of reinforcing tape intermediate said base and said :presser foot in the direction of feeding movements of said articles, means for simultaneously imparting sewing movements to the needle and feeding movements to said feeding means, means for cutting said tape adjacent the opposite sides of said articles, common control means for said needle, tape-feeding means and cutter means, said control means comprising a finger normally lying within the path of travel of said articles and biased toward said position, said finger, adjacent its leading edge, being provided with a pair of cam steps, successive engagement of each :of which by the articles moving said finger progressively laterally of said path of travel, the first of said steps initiating sewing movements to the needle and feeding movements to the tape, and the second of said steps causing cutting movements to be imparted to said cutter means, said finger also including, adjacent its trailing edge, a pair of steps which progressively allow said finger to return in the direction of its normal position upon passage of the articles there- -over, the first of said steps operating said cutter mechanism and the latter thereof imparting terminating movements to the needle and said feeding means.

2. In a sewing machine means for stitching articles successively fed in spaced relation, means for feeding a strip of reenforcing tape with said articles past the stitching means, drive means for simultaneous operation of said stitching and feeding means, means positioned beyond the needle in the line of travel for cutting said tape at opposite sides of said articles, normally inoperative drive means for said tape cutting means, and a single article engageable control member positioned in part forward of the needle and responsive to movements of the articles through the machine operative to successively set said first drive means into operation, render said second drive means operative in sequence and discontinue the operation of said first drive means.

3. In a machine for stitching articles successively fed in spaced relation and stitching lengths of tape thereto, a base plate, having a slot therein, a needle at one side of the base plate, a presser foot at the same side of the base plate, feed means at the opposite side of the base plate and operative through the slot therein in cooperation with the presser foot for feeding said articles with a strip of tape past the needle, drive means for jointly operating the needle and feed means, a switch controlled clutch in said drive means, means positioned beyond the needle in the line of travel for cutting said tape at opposite sides of said articles, normally inoperative drive means for said, cutting means and asingle article engageable control finger positioned in part forward of the needle and movable laterally of the base plate through pressure contact of the articles therewith in their movement through the machine, and connections between said finger and said switch and normally inoperative drive means operative to initiate operation of the needle and feed means, cut the tape at opposite sides of the articles and discontinue operation of the needle and feed means.

4. The structure according to claim 3, wherein said connections comprise a pivotally supported switch arm, a second arm for operatively controlling the said drive means for the cutting means, said second arm being spring biased toward said base plate and being connected to said control finger, and said switch arm normally contacting said second arm for movement of the switch arm to switch closing position upon lateral movement of the control finger outwardly of the base plate.

5. The structure according to claim 4 wherein said base plate is provided with a channel in which the control finger is normally disposed,

6. The structure according to claim 3 wherein said control finger comprises an elongated straight base portion, a shoulder at the rear end thereof, a shoulder at the front end thereof in the plane of the first shoulder, a cam portion interconnecting the second shoulder and the base portion and a curved portion at the front end, merging into said second shoulder.

7. In a sewing machine, a base plate, stitching and feeding means operatively associated with the base plate, drive means for the stitching and feeding means, tape cutting means, including a fixed blade at one side of said base plate, a movable blade at the opposite side of said base plate, the movable blade being rigidly connected to one end of an arm, the opposite end of the arm having a head rotatably journalled on a shaft parallel with said base plate, a spring on said shaft engaged with said arm for normally holding said movable blade in inoperative position, ratchet teeth on one end of said head, a crank arm including a head rotatably supported on said shaft adjacent said first head and having ratchet teeth thereon for cooperation with the first ratchet teeth, means operable by said drive means for constantly oscillating said last arm, a third arm having a head at one end thereof rotatably supported on said shaft, cam means between the heads of said crank arm and said third arm for moving the ratchet teeth on said first head and the head on said crank arm into operative engagement upon rotation of the head of the third arm on said shaft, and a control finger adjacent the base plate and laterally movable upon contact of articles therewith upon being fed past the stitching means connected with the opposite end of said third arm.

8. The structure according to claim 7 wherein said base plate is provided with a channel, and spring means engaged with said third arm for normally holding said control finger in said channel.

9. The structure according to claim 7 wherein said cam means comprises a cam lug on the head of said third arm, a collar supported on said shaft for axial movement thereon, and engageable with the head on said crank arm, and a cam lug on said collar for cooperation with the first cam lug.

10. The structure according to claim 7 wherein the head on said first arm is provided with a recess, and a coil spring encircling said shaft and disposed in said recess in opposition to'the head on said crank arm for normally holding the ratchet teeth disengaged.

11. The structure according to claim '7, together with a clutch in said drive means a solenoid for operating said clutch, a switch for controlling said solenoid, a switch operating arm, and an adjustable abutment on said arm engageable by said third arm upon initial movement of the control finger laterally of the base plate.

12. In a sewing machine, means for stitching articles successively fed in spaced relation, said means including a base plate and a sewing head, said head having a presser foot and cooperating needle, means for feeding said article and a continuous strip of reinforcing tape intermediate said base and said presser foot in the direction of feeding movements of said articles, means for simultaneously imparting sewing movements to the needle and feeding movements to said feeding means, means positioned beyond the needle in the line of feed for cutting said tape adjacent the opposite sides of said articles, common control means for said needle, article and tape feeding means and cutter means, said control means comprising a finger normally lying in a position within the path of travel of said articles and biased toward said position, said finger, adjacent its leading end being provided with a pair of cam steps aligned longitudinally of the lineof feed, engagement of each of which by the articles moving said finger progressively laterally of said path of travel, the first of said steps initiating sewing movements to the needle and feeding movements to the tape, and the second of said steps causing cutting movements to be imparted to said cutter means, and said first step extending forwardly of the needle.

HAROLD V. KINDSETI-I. JEAN E. ZELLER, JR.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,061,431 McCulloh Nov. 17, 1936 2,151,438 Pierce Mar. 21, 1939 2,171,130 Merrifield Aug. 29, 1939 2,362,462 Belcher Nov. 14, 1944