US2690725A

US2690725A - Means for automatically exchanging bobbins in sewing machines

Info

Publication number: US2690725A
Application number: US381776A
Authority: US
Inventors: Schumann Herbert; Clauss Emil
Original assignee: GM Pfaff AG
Current assignee: GM Pfaff AG
Priority date: 1951-08-09
Filing date: 1953-09-23
Publication date: 1954-10-05
Anticipated expiration: 1971-10-05
Also published as: GB721975A; DE947664C; GB745185A; US2733676A; CH338085A; NL93071C; CH309894A; FR1064762A; FR65297E

Description

H. scHUMANN E-rm. 2,690,725 MEANS FOR AUTOMATICALLY EXCHANGING BOBBINS IN SEWING MACHINES mad sept. 23, 195s s sheets-sneer 1 Oct 5, 1954 H. SCHUMANN ErAn. 2,590,725

MEANS PoR AUTOMATICALLY ExcHANGING EoBBINs 1N sEwING MACHINES Filed Sept. 23, 1953 3 Sheets-Sheet 2 Oct. 5, i954 H, SCHUMANN ErAL 2,690,725

MEANS FOR AUTOMATICALLY EXCHANGING BOBBINS IN SEWING MACHINES med sept. 23, 1953 3 sheets-sheet s lstented Oct. 5, 1954 MEANS FOR AUTOMATICALLY EXCHANGING B OBBINS IN SEWING MACHINES Herbert Schumann and Emil Clause, Kaiserslautern (Pfalz), Germany, asignen to G. M. Pl'ai! A. G., Kaiserslautern (Pfalz), Germany Application September 23, 1953, Serial No. 381,776

Claims priority, application Germany September 24,1952

(Ul. i12- 186) 18 Claims.

This invention relates to certain improvements in the device for exchanging bobbins in sewing machines which has been described in our copending application Ser. No. 302,895.

In accordance with our said prior patent application the empty bobbin with bobbin case is seized by a grip claw carrier disposed axially parallel to the loop catch which executes a combination of axial and pivotal movements, is lifted from the seat in the loop catch and subsequently dropped during the pivotal movement of the grip claw carrier, while at the same time a bobbin case with a full bobbin is picked up from the magazine and deposited in the seat in the loop carrier.

It is an object of the present invention to further simplify the mechanism of such a device and to provide better accessibility for the stitch-forming members disposed beneath the bed plate.

A further object of the invention is to improve the cooperation between the grip claw carrier, the hook and the container or magazine feeding the full bobbins.

With these and further objects in view, according to the present invention the shifting shaft which is arranged in the bed plate of the machine, parallel to the loop catch or looper shaft, with the grip claw carrier flxedly mounted thereon, is provided with a shift pin which is guided in straight and helical grooves or slots of a sleeve enclosing the shifting shaft.

In this way, the previous control mechanism for the grip claw carrier, consisting of a springurged toothed rack and a cam, can be dispensed with whereby the device is simplified and its reliability increased. Also, the stitch-forming members arranged below the bed plate thus remain freely accessible.

Furthermore, by the arrangement and construction of the mechanism according to the present invention a radial adjustment of the grip claw carrier is rendered possible. Such adjustment permits accurate alignment of the claws in relation to the looper and the magazine which is preferably shaped in the form of a tubular cartridge. 'Ihe releasing member for feeding the bobbin cases in the cartridge may suitably be provided on the holder of the cartridge for operation by a cam arranged on the shifting shaft of the control mechanism.

Other and further objects, features and advantages of the invention will be pointed out hereinafter and appear in the appended claims forming part of the application.

In the accompanying drawings a. now preferred Fig. 1 is a perspective view of a sewing machine having the invention applied thereto, as viewed from below, with the device for mechanically changing the bobbins in the position of rest.

Fig. 2 is a perspective view of the shifting shaft with the control members, the compression spring, the catch member and the grip claw carrier.

Fig. 3 is a perspective view of the control case,

Fig. 4 is a perspective view of a spring member for the control,

Fig. 5 is a perspective view of a guide rod including the slide member,

Fig. 6 is a side View of a discarding claw,

Fig. 7 is a side view of an inserting claw, heFig. 8 is a perspective View o1' a scraper mem- Fig. 9 is a perspective view of a cartridge tube with cap,

Fig. 10 is a perspective view of the insert of the cartridge,

' Fig. 11 is a cross-section of a guide pin, on the line XI-Xl of Fig. 10, and

Fig. 12 is a fragmentary perspective view of the machine and the bobbin exchanging device, viewed from below, with the cartridge holder in open position.

Similar reference numerals denote similar parts in the diierent views.

Referring to the drawings in greater detail, it will be seen that al1 parts of the bobbin. exchanging device are secured in and on the forward bearing body I and the rearward bearing body 2 for the looper shaft. The shifting shaft 3 is mounted for axial and rotary motion in the forward bearing body I and in a casing 44 screwed to the rearward bearing body 2. Two sleeve members 5 and 6 with complementary end faces surround the shifting shaft 3 and in their turn 'are accommodated in a tubular casing 4. The sleeve member 5 is secured against changes of its position in an axial direction on the one hand by a nose 'l engaging the inner face of a recess B of the casing I and on the other hand by the bearing body 2 to which the casing 4 is screwed. To the same end the member 6 is provided with a collar 9 which is urged against the casing 4 by a cover II screwed on a thread I0 of casing l. The member 8 is secured against rotation by a pin I2 on the casing l which pin is engaged in a groove I3 of collar 9. The sleeve member 5 is slightly adjustable in an angular or circumferential direction by two adjusting screws I4 and I5 in casing 4 which in turn is secured to the rearward bearing body 2 with the aid of two fixing pins I6 and embodiment of the invention is shown by way of ascrew I8 extending througha bore I1.

illustration and not by way of limitation.

Each 0f the two sleeve members B'and 6 has ascenso two guide slots |9 and 2n for a shifting pin 2| secured in the shifting shaft 3 and projecting therefrom on both sides. The two slots are relatively displaced by 180". From the slots I9 and 20 only the upper ones are visible in Fig. 2. In each of the two guide slots 20 of the sleeve member 6 there is seated a spring tongue 23 secured by a screw 22. The front end 24 of the tongue is enlarged and fits in a. recess 25 of the sleeve member 5. Also the end 24 of the spring tongue is thickened and fitted on its under side to the outer diameter of the shifting shaft 3 and on its end face to the helical face of the sleeve member 6 which together with the adjacent helical face of the sleeve member forms a helical slot 26.

The angular or rotational adjustment of the sleeve member 5 by fractions of a millimeter does not impair the operation of the pin and slot connection, but is sunicient for accurate adjustment of the grip claws.

Clamped between the cover of the casing 4 and a catch 28 secured on the shifting shaft 3 by means of two screws 21 is a compression spring 29 with two washers 30. Said spring causes the return of the Ashifting shaft 3 into the position of rest and thus the lifting-out and swinging motion, through the pin and slot connection. The front end of the shifting shaft 3 is provided with a groove 3| for guiding a cam 32 which is freely movable in a longitudinal direction of the shaft and operates the releasing device for the bobbin cases in the cartridges.

A guide rod 33 is secured on the forward bearing body by means of a screw 34 and by means of a screw 35 on the rearward bearing body 2. Guided thereon is a slide member 36 whose fork 31 engages in an annular groove 38 of the catch 28. A pin 39 of the slide member 36 forms the connecting element to the means for operating the device for exchanging the bobbins.

A grip claw carrier 40 is secured on the shifting shaft 3 by means of a conical pin 4| and carries in two bores 42 a pair of

grip claws

44 and 45 each of which is secured in position in its bore 42 by a screw 43. Leaf springs 41 are secured on the grip claw carrier 40 by means of screws 45 and press with their free ends on conical pins 48, Figs. 6 and 7, of the

grip claws

44 and 45.

The two

grip claws

44 and 45 differ from each other only by the formation of their hook-shaped members 49 and 50 which are rotatably mounted on a bridge member 5| by means of a pin 52. The discarding claw 44 has a smooth hook member 49 and the inserting claw 45 has a hook member 50 provided with a nose 53 and serving to release the bobbin case B automatically from the grip claw when inserting a bobbin case B with full bobbin into the lopper of the machine, by the nose 53 striking against the lower part of the bobbin case and moving a hook 54 out of engagement with the bobbin case.

Both forms of the hook member have the same hook 54 and a set pin 55; they are under action of a compression spring 56 seated in a recess of bridge member 5| which is rotatably mounted, by means of a pin 51, in a slot 58, Fig. 1, of the grip claw body 59 and has on its upper edge two grooves or notches 60 for the point'of the conical pin 48. The effect of this arrangement is hereinafter described in greater detail. The rear end of the bridge 5| is formed as a fork 6|. A depression 52 for the screw 43 is provided on the upper cylindrical part of each of the grip claws.

A scraper 63 is guided in a groove 64 in the forward bearing body VI, parallelly to the looper shaft, and secured by means of a knurled screw S5 passing through a guide slot 66. A pin 61 held in a dwell in the bearing body for the looper shaft, which dwell is not visible in -Fig. 1, serves to secure the scraper 63 in its working position. The parts becoming operative when stripping olf a bobbin case with empty bobbin are a cam surface 88 and a forcing pin 69 on the front end of the scraper 63.

- Detachably mounted on the forward bearing body I for the looper shaft, parallelly to the shifting shaft 3, is a magazine or cartridge 10 having a mouthpiece 1| and a closure cap 12, which is provided with a knurled rim 13, Fig. 9. and held by means of two pins 15 engaging in two bayonet slots 14. A bottom plate 16 has two guide pieces 11 and 18 of different size fitting in corresponding recesses 19 and 80 of the cartridge tube. Secured in the bottom plate 16 is a 'guide pin 8| on which slides a feeding sleeve 82 which is urged towards the mouthpiece 1| by means of a helical spring 83 disposed between a ring 84 of the bottom plate 18 and the bottom 85 of the feeding sleeve 82.

The guide pin 8| has an approximately semicircular cross section with a guide ridge 86 which is provided with dwells or

grooves

81, 88, and 89. The head 90 of the guide pin is shaped similarly to the holding pin for the bobbin case in the looper of the machine, but the mushroom shape of the head which in case of the holding pin for the bobbin casing is formed by an annular groove, in this case is interrupted in that the guide pin cross section partly extends up to this head.

The bottom 85 of the feeding sleeve 82 is provided with a bevelled face 9| and a groove 92 which both have the purpose of making accessible for shifting operation a shift member 93 whose configuration corresponds to the upper part of a known bobbin casing, except that the hook-94 of the slide 95 in the shift member 93 is somewhat shortened in relation to the hook on the slide ci' a bobbin case.

The mouthpiece 1| s provided with a guide groove 98 into which terminates a shift slot 91. A recess 98 is provided for free passage of the bobbin case, since the wall of the mouthpiece opposed to the recess encloses the -bobbin case more closely than the tube oi' the container or magazine.

The magazine is secured in its position by a bore 99 in the magazine tube and a groove |00, Fig. 1, with slanting guide faces 00a on both sides of the outer periphery of the mouthpiece 1|. The magazine holder substantially consists of a holder plate |0|, a hinged semicircular lever or stirrup |02 and two carrier shells |03 and |04, Fig. 12. The holding plate |0| is secured to the forward bearing body l of the machine by means of two screws |05 and |08 and secured in `position by means of two setpins |01 and |08. A pin |09 projects through the carrier shell |03 provided on the holding plate |0|, as a counterpart to the bore 99 in the magazine. A bent member I I0 is fastened on the holding plate |0| by means of screws |08 and for holding the cam 32 in its operating position, which cam is overhung on the shifting shaft 3. A releasing lever I I2 is pivotally mounted on the holding plate. |0| by a screw H3, and urged against the cam 32 by means of a spring ||4. A locking bolt ||5 is revolubly received in a recess of the holding plate |0| by means of a pin ||6 and acted upon by a compression spring ||1.

The stirrup |02 is hingedly connected to the holding plate by means of a hinge pin ||0 and carries the carrier shell |04 on which spring clip |20 is secured by means of two screws Ill. The front end of the hinged stirrup |02 is formed with a rectangularly bent-'off member forming a handle |2|, and a safety angle member |22 is fastened by means of two screws |23.

The operation of the device is as follows:

The movement of an operating lever, not shown, which may be secured on the bed plate of the machine or on the frame is transmitted to the pin 39 of the slide member 38. shifting the same on the guide rod 33 from the position of rest shown in Fig. 1 towards the rearward bearing body 2 for the looper shaft. the longitudinal movement being transferred, through the fork 31 and catch 28, to the shifting shaft 3 which is mounted for axial and rotary movement both in the forward bearing body l and in the casing 4 fixed on the rearward bearing body 2. By the said movement the shifting pin 2| secured in the shifting shaft 3 is guided on a straight line, in the slots 20 of the link member 8 and beneath the spring tongues 28, into the slots i9 of the link member 5. Simultaneously the grip claw carrier 40 secured on the shifting shaft 3 is moved towards the looper of the machine and the magazine in such a manner that the discarding claw 44 seizes the empty bobbin casing in the looper and the inserting claw 45 seizes the full bobbin case in the magazine. accurate angular adjustment of the grip claws being possible by adjustment of the sleeve member 5, and thus of the slots I9, by the screws I4 and i5 acting upon the nose 1.

As the operating lever is released, the shifting shaft 3 moves back under action of the loaded compression spring 29, whereby the shifting pin 2| at rst moves with its two ends in the slots I9.v

then running against the ends 24 of the spring tongues and being deflected into the helical slots 26 which in turn guide it back into the slots 20. Simultaneously with this retrograde movement the shifting shaft 3. caused by the helical slots 28, makes half a revolution. Hereat, the

grip claws

44 and 45 execute a pivotal movement by ,which the discarding claw is moved pastthe scraper 63, whereby the empty bobbin casing is scraped off and the inserting claw 45 with the full bobbin case is moved into its position for cooperation with the looper. The cam 32 which is freely movable on the shifting shaft 3 and guided in the groove 3|, is held in its position by the holding plate |0| and the stirrup I0, so that it partakes only in one half of the revolution of the shifting shaft 3 in the cycle of operations hitherto described.

By a second operation of the operating lever the said cycle of operations is repeated. Hereat, the inserting claw 45 inserts the full bobbin case into the looper, while the discarding claw 44 executes an idle stroke. Then follows a second revolving motion of 180 of the grip claw carrier.

The gripping of the bobbin cases by the

grip claws

44 and 45 takes place in such a way that the bobbin case B is at rst engaged by the fork member 8l and then by the hook member 43 or 50. To this end the hook members are movably mounted n the bridge and acted upon by the compression spring 58, so that the hook 54 is permitted to slide over the nose |24 of the bobbin case hinge |25 and seizes the same. The adjustingpin 55 and thecatch devices on the bridges of the grip claws cooperate with the 6 scraper 83 in such a way that theadiusting pins Il run against the cam face 88 as the grip claw carrier 40 is swung, thereby being' moved in an anti-clockwise direction, referring to Figs. 6 and '1. The hook 54 is thus released from the bobbin casing, against action of the spring 58, and simultaneously the bridge '8| is pivoted about the pin l1 in the same direction, until the conical pin 48 catches inthe second locking groove 80. Thus both of the grip claws have' been erected on moving past the scraper and brought into the gripping position. The inserting claw is always moved past the scraper without bobbin case and is only erected while 'the discarding claw is erected and its hook 84, as hereinbefore described. is released. The discarding of the bobbin case with empty bobbin is assisted by the forcing pin 88.

In order to replenish the magazine, the feeding sleeve 82 is urged against the bottom plate 18, with compression of the spiral spring 83, to such an extent that the slide or bobbin case hinge '8l catches in the groove Il. Now the bobbin cases with full bobbins are threaded on the guide pin 8|, and the guide ridge 88 fits and slides in a groove of the bobbin case hinge |25. This is known in the art and, therefore, not shown in detail. If the guide pin 8| is covered with bobbin cases throughout its free length, the feeding sleeve 82 is released from the groove 81 by digital pressure on the hook 94. Thus all bobbin cases, with the exception of the foremost one, are under the pressure of the helical spring 83. The foremost bobbin case B is released from the pressure of the feeding spring because the bobbin case hinge of the next bobbin case is held in the groove 88. The full insert is now introduced into the magazine 10. Hereat, the guide'members 11 and 18 of different size ensure the correct alignment of the bobbin cases in relation to the mouthpiece 1|. Finally the closure cap 12 is put In order to insert the magazine into the machine, it is urged into the downwardly swung shell |04 where it is held in position by the spring clip |20. By manual turning of the magazine with simultaneous pull in the direction towards the closure cap .12 the nose of the safety angle member |22 slides pastvone of the guide faces |00a into the groove |00, whereby the bore 99 in the magazine 10 and the pin |09 in the carrier shell |03 are simultaneously aligned.` 'As the lower part of the holder is now swung upwards by means of the handle |2|, the locking bolt ||5 snaps in under the handle |2|, Fig. 1. Both the magazine and the bobbin cases contained therein are now in a predetermined position in relation to the looper of the machine.

As the bobbin case exchanging device is operated, the inserting claw 45 at rst picks the foremost bobbin case B from the mouthpiece 1|. On the second swinging movement of the grip claw carrier 40 the cam 32 then moves the releasing lever ||2 in such a way that the nose ||2a thereof presses on the hook of the bobbin case hinge of the hitherto second bobbin case in'the magazine through the shifting slot 91 of the mouthpiece 1|. Thus the bobbin case is released from the groove 88 and advanced by action of the helical spring 83, until its bobbin case hinge |28 catches in the groove 89. Hereat, the guide groove 96 in which the hook |24 of. the bobbin case hinge |25 slides, secures the bobbin case additionally against rotational displacement on the guide pin 8l. Simultaneously the remailling supply of bobbin cases has been advanced by the length of one bobbin case, until the bobbin case hinge of the actual second bobbin case is held by the groove 88.

The aforedescribed process is repeated with every bobbin case exchange until the supply in the magazine is exhausted. In this case, the slide 85 of the, feeding sleeve 82 has reached the groove 88 and remains in this position even with further shifting operations. since the nose Illa of the releasing lever il! does not reach the hook N of the slide 95,-because the hook 9| is correspondingly shortened as compared to normal bobbin cases.

While the invention has been described in detail with respect to a now preferred example and embodiment -of the invention it will be understood by those skilled in the art after understanding the invention that various changes and modifications may be made without departing from the spirit and scope of the invention and it is intended, therefore, to cover all such changes and modifications in the appended claims.

We claim:

LA device for mechanically exchanging the bobbins in the looper of a sewing machine having a bed plate, a looper, and a looper shaft, said device comprising a magazine adapted to be filled with a plurality of bobbin cases with full bobbins. a shifting shaft shiftably and rotatably mounted on the bed plate of the machine, parallel to the looper shaft, a grip claw carrier fixedly mounted nsl on said. shifting shaft and having a pair of grip claws, means for automatically and successively moving each of the bobbin cases in the magazine into a preparatory yielding position at the forward end thereof. and means for imparting a combination of axial and pivotal motions to said shifting shaft for lifting the empty bobbin case from its seat in the looper and discarding it, picking up the next full bobbin case from the forward end of the magazine, and inserting said bobbin case into the looper in a position ready for sewing, the latter means comprising a guide pin secured in the shifting shaft, and a sleeve surrounding the shifting shaft and provided with straight and helical recesses for guiding said guide pin.

2. A device for mechanically exchanging 'the bobbins in the looper. of a sewing machine having a bed plate, a looper, a looper shaft, a forward and a rear bearing for the looper shaft, said device comprising a magazine adapted to be filled with a plurality of bobbin cases withfull bobbins, a casing secured to the rearward bearing body, a shifting shaft shiftably and rotatably mounted in the forward bearing body and in said casing, a grip claw carrier xedly mounted on said shifting shaft and having a pair of grip claws, means for automatically and successively moving each of the bobbin cases in the magazine into a preparatory yielding position at the forward end thereof, and means for imparting 'a combination of axial and pivotal motions to said shifting shaft for lifting the .empty bobbin case from its seat in the looper and discarding it, picking up the acciones ing a bed plate, a looper. a looper shaft, a forward and a rearward bearing body for the looper shaft, said device comprising a magazine adapted to be filled with a plurality of bobbin c ases'with full bobbins, a casing secured to the rearward bearing body, a shifting shaft shiftably and rotatably mounted in-the'forward bearing body and in said casing, a grip claw carrier flxedly mounted on said shifting shaft and hav-4 ing a pair of gripclaws, means for automatically and successively moving each of the bobbin cases in the magazine into a preparatory yielding position at the forward end thereof, and means for imparting a combination of axial and pivotal motionsto said shifting shaft for lifting the empty bobbin case from its seat in the looper and discarding it. picking up the next full bobbin case from the forward end of the magazine, and inserting said bobbin case into the looper in a position ready for sewing,lthe latter means comprising a guide pin secured in the shifting shaft, and two complementary sleeve members accommodated in the casing and defining between their adjacent end faces straight and helical slots for guiding said guide pin, one of said sleeve members being rotatively adjustable.

4. A device for vmechanically exchanging the bobbins in the looper of a sewing machine having a bed plate, a looper, a looper shaft, a forward and a rearward bearing body for the looper shaft, said device comprising a magazine adapted to be filled with a plurality of bobbin cases with full bobbins, a casing secured to the rearward bearing body, a shifting shaft shiftably and rotatably mounted in the forward bearing body and in said casing, a grip claw carrier i'lxedly mounted on said shifting shaft and having a pair of grip claws, means for automatically and successively moving each of the bobbin cases in the magazine into a preparatory yielding position at the forward end thereof, and means for imparting a combination-of axial and pivotal motions to said shifting shaft for lifting next full bobbin case from the forward end of A the empty bobbin case from its seat in the looper and discarding it, picking up the next full bobbin case from the forward end of the magazine, and inserting said bobbin case into the looper in a position ready for sewing, the latter means comprising a guide pin secured in the shifting shaft, and two complementary sleeve members accommodated in the casing and dening between their adjacent end faces straight and helical slots for guiding said guide pin, one of said sleeve members being rotatively adiustable, and two unilaterally'enlarged spring tongues on the forward one of the sleeve members.

5. A device for mechanically exchanging the bobbins in the looper of a sewing machine having a bed plate, a looper, and a looper shaft. a forward and a rearward bearing body for the looper shaft, said device comprising a magazine adapted to be filled with a plurality of bobbin cases with full bobbins, a casing secured to the rearward bearing body, a shifting shaft shiftably and rotatably mounted in the forward bearing body and in said casing, a grip claw carrier tlxedly mounted on said shifting shaft and having a pair of grip claws, means for automatically and successively moving each of the 'bobbin cases in the magazine into a preparatory yielding position at the forward end thereof, and means for imparting a combination of axial and pivotal motions to said shifting shaft for lifting the empty bobbin case from its seat in the looper and discarding it, picking up the 9 next full bobbin case from the forward end of the magazine, and inserting said bobbin case into the looper in a position ready for sewing, the latter means comprising a guide pin secured in the shifting shaft, two complementary sleeve members accommodated in the casing and dening between their adjacent end faces straight and helical slots for guiding said guide pin. one

of said sleeve members being rotatively adjustable, a. catch secured on the shifting shaft, and a pressure spring placed around the shifting shaft tbetween the casing and. the catch.

6. A device for mechanically exchanging the bobbins in the looper of a sewing machine havmg a bed plate, a looper, and a looper shaft, a forwardand a rearward bearing kfor the looper shaft, said device comprising a magazine adapted to be lled with a plurality of bobbin cases with full bobbins, a casing secured .to the rearward bearing body, a shifting shaft shiftably and rotatably mounted in the forward bearing body and in said casing, agrip claw carrier xedly mounted on said shifting shaft and having a pair of grip claws, means for automatically and successively moving each of the bobbin cases in the magazine into a preparatory yielding position at the forward end thereof, and means for imparting a -combination of axial and pivotal motions to said shifting shaft for lifting the emptybobbin case from its seat 'in the looper and discarding it, picking up the next full bobbin case from the forward end of the magazine, and inserting said bobbin case into the looper in a position ready for-sewing, the latter means comprising a guide pin secured in the shifting shaft, two complementary sleeve members accommodated in the casing and de. fining-between their adjacent end faces straight and helical slots for guiding said guide pin, one of said sleeve members being rotatively adjustable, and a cam which is freely movable ina longitudinal direction of the shifting shaft and guided in a groove thereof.

7. A device for mechanically exchanging the bobbins in the looper of a sewing machine having a bed plate, a looper, and a looper shaft, a forward and a rearward 'bearing for the' looper shaft, said device comprising a magazine adapted to be filled with a plurality of bobbin cases with full bobbins, a casing secured to the rearward bearing body, a shifting shaft shiftably and rotatably mounted in the forward bearing body and in said casing, a grip claw carrier flxedly mounted on said shifting shaft and having a pair of grip claws, means for automatically and successively moving each of the bobbin cases in the magazine into a preparatory yielding position at the forward end thereof, and means for imparting a combination of axial and pivotal motions to said shifting shaft for lifting the empty bobbin case from'its seat in the looper and discarding it, picking up the next full bobbin case from the forward end of the magazine, and inserting said bobbin case into the looper in a position ready for sewing, the latter means comprising a guide pin secured in the shifting shaft, two complementary sleeve members accommodated in the casing and defining between their adjacent end faces straight and helical slots for guiding said guide pin, one of said sleeve members being rotatively adjustable, a straight guide disposed parallelly to the shifting shaft, and a slide member having a pin and a fork and being overhung on said straight guide.

8. A device for mechanically exchangingA the bobbins in the looper of a sewing machine having a bed plate, a looper, and a `looper shaft, said device comprising a magazine adapted to be filled with a plurality of bobbin cases with full bobbins, a shifting shaft shiftably and rotatably mounted onv the bed plate, a grip clavP carrier fixedly mounted on said shaft and having a pair of grip claws, means 'for automatically and successively moving each .of the bobbin cases in the magazine into a preparatory yielding position at the forward end thereof, and means for imparting a combination of axial and pivotal motions to saidl shifting shaft for lifting the empty bobbin case from its seat in the looper and discarding it, picking up the next full bobbin case from the forward e`nd of the magazine, and inserting said bobbin case into the looper in a position ready for sewing, the latter means comprising a guide pin secured in the shifting shaft,

a sleeve surrounding the shifting shaft and provided with straight and helical recesses for guiding said guide pin, a movable hook member provided on the front end of each of the grip claws. a pressure spring acting upon said hook member, and an adjusting pin secured to the end of the hook member facing away from the point of the hook.

9. A device for mechanically exchanging the bobbins in the looper of a sewing machine having a bed plate, a looper,and a looper shaft, said device comprising a magazine adapted to be filled with a plurality of bobbin cases with full bobbins, a shifting shaft shiftably and rotatably mounted on the bed plate, a grip claw carrier xedly v mounted on said shaft and having a pair of grip claws, each of said grip claws having a bridge with two vgrooves and a catch pin adapted to cooperate therewith, means for automatically and successively moving each of the bobbin cases in the magazine into a preparatory yielding posivtion at the forward end thereof, and means for imparting a combination of axial and pivotal motions to said shifting shaft for lifting the empty bobbin case from its seat in the looper and discarding it, picking up the next full bobbin case from the forward end of the magazine, and inserting said bobbin case into the looper in a position ready for sewing, the latter means comprising a guide pin secured in the shifting shaft, a sleeve surrounding the shifting shaft and provided with straight and helical recesses for guiding said guide pin, a movable hook member provided on the front end of each of the grip claws, a pressure spring acting upon said hook member, and an adjusting pin secured to the end of the hook member facing away from the point of the hook.

10. A device for mechanically exchanging the bobbins in the looper of a sewing machine having a bedl plate, a looper, and a looper shaft, said device comprising a magazine adapted to be filled with a plurality of bobbin cases with full bobbins, a shifting shaft shiftably and rotatably mounted on the bed plate, a grip claw carrier iixedly mounted on said shaft and having a pair of grip claws, one for lifting and discarding the empty and one for inserting the full bobbin and bobbin case, each of said grip claws having a bridge with two grooves and a catch pin adapted to cooperate therewith, means for automatically and successively moving each of the bobbin cases in the magazine into a preparatory yielding position at the forward end thereof, and means for imparting a combination of axial and pivotal motions to each shifting shaft for lifting the empty bobbin case from its seat in the looper and discardingit, picking up the next full'bobbin case from the forward end of the magazine, and inserting said bobbin case into the looper in a position ready for sewing, the latter means comprising a guide pin secured in the shifting shaft. a'sleeve surrounding the shifting shaft and provided with straight and helical recesses for guiding said guide pin, a movable hook member provided on the front end of each of the grip claws, a pressure spring acting upon said hook member, and an adjusting pin secured to the end of the hook member facing away from the point of the hook, the hook member on the inserting grip claw being provided, on the side facing away from the pressure spring, with a nose projecting in the form of a ridge, whose lower face extends parallel to the direction of the hooks.

11. A device for mechanically exchanging the bobbins in the looper of a sewing machine having a bed plate, a. looper, and a looper shaft, said device comprising a magazine adapted to be illled with a plurality of bobbin cases with full bobbins, a shifting shaft shiftably and rotatably mounted on the bed plate, a grip claw carrier xedly mounted on said shaft and having a pair ofgrip claws, means for automatically and successively moving each of the bobbin cases in the magazine into a preparatory yielding position at the forward end thereof, and means for imparting a combination of axial and pivotal motions to said shifting shaft for lifting the empty bobbin case from its seat in the looper and discarding it, picking up the next full bobbin case from the forward end of the magazine. and inserting said bobbin case into the looper in a position ready for sewing, the latter means comprising a. guide pin secured in the shifting shaft, a sleeve surrounding the shifting shaft and provided with straight and helical recesses for guiding said guide pin, a scraper provided on the bed plate of the machine and being adiustable parallel to the looper shaft, said scraper having a forcing pin and a cam edge, and set pins arranged on the grip claws in such a way that the cam .edge projects into the path of travel of said Set pins.

12. A device for mechanically exchanging the bobbins in the looper of a sewing machine having a bed plate, a looper, and a looper shaft, said device comprising a magazine adapted to be filled with a plurality of bobbin cases with full bobbins, said magazine having a guide pin whose front end is shaped similarly to the retaining pin for the bobbin case in the looper of the machine, a shifting shaft shiftably and rotatably mounted on the bed plate, a grip claw carrier fixedly mounted on said shaft and having a pair of grip claws, means for automatically and successively moving each of the bobbin cases in the magazine into a preparatory yielding position at the forward end thereof, and means for imparting a combination of axial and pivotal motions to said shifting shaft for lifting the empty bobbin case from its seat in the looper and discarding it, picking up the next full bobbin case from the forward end of the magazine, and inserting said bobbin case into the looper in a position ready for sewing, the latter means comprising a guide pin secured in the shifting shaft, and a sleeve surrounding the shifting shaft and provided with straight and helical recesses for guiding said guide pin.

13. A device for mechanically exchanging the bobbins in the looper of a sewing machine having a bed plate, a looper, and alooper shaft, said del2 vice comprising a magazine adapted to be filled with a plurality of bobbin cases with full bobbins, said magazine having a guide pin whose front end is shaped similarly to the retaining pin for the bobbin case in the looper of the machine, said guide pin being provided with a guide ridge and with catch grooves in said guide ridge, a shifting shaft shiftably and rotatably mounted on the bed plate, a grip claw carrier ilxedly mounted on said shaft and having a pair of grip claws,

means for automatically and successively moving each of the bobbin cases in the magazine into a preparatory yielding position at the forward end thereof, and means'for imparting a combination of axial and pivotal motions to said shifting shaft for lifting the empty bobbin case from its seat in the looper and discarding it, picking up the next full bobbin case from the forward end of the magazine, and inserting said bobbin case into the looper in a position ready for sewing, the latter means comprising a guide pin secured in the shifting shaft, and a sleeve surrounding the shifting shaft and provided with straight and helical recesses for guiding said guide pin.

14. A device for mechanically exchanging the bobbins in the looper of a sewing machine having a bed plate, a looper, and a looper shaft, said device comprising a magazine adapted to be filled with a plurality of bobbin cases with full bobbins, said magazine having a guide pin whose front end is shaped similarly to the retaining pin for the bobbin case in the looper of the machine, said guide pin being provided with a guide ridge and .with catch grooves in said guide ridge, a bottom -plate in which said guide pin is secured and which is provided with guide members of different size, a shifting shaft shiftably and vrotatably mounted on the bed plate, a grip claw carrier fixedly mounted on said shaft and having 'a pair of grip claws, means for automatically and successively moving each of the bobbin cases in the magazine into a preparatory yielding position at the forward end thereof, and means for imparting a combination of axial and pivotal motions to said shifting shaft for lifting the empty bobbin case from its seat in the looper and discarding it, picking up the next full bobbin case from the forward end of the magazine, and inserting said bobbin case into the looper inv a position ready for sewing, the latter means comprising a guide pin secured in the shifting shaft, and a sleeve surrounding the shifting shaft and provided with straight and helical recesses for guiding said guide pin.

l5. A device for mechanically vexchanging the bobbins in the looper of a sewing machine having a bed plate, a looper, and a looper shaft, said device comprising a magazine adapted to be filled with a plurality of bobbin cases with full bobbins, 'said magazine having a guide pin whose front end is shaped similarly to the retaining pin for the bobbin case in the looper of the machine, said guide pin being provided with a guide ridge and with catch grooves in said guide ridge, a bottom plate in which said guide pin is secured and which is provided with guide members of different size, a shifting shaft shiftably and rotatably mounted on the bed plate, a grip claw carrier iixedly mounted on said shaft and having a pair of grip claws, means for automatically and successively moving each of the bobbin cases in the magazine into a preparatory yielding position atthe forward end thereof, and means for imparting a combination of axial and pivotal motions to said shifting shaft for lifting the empty bobbin case from its seat in the looper and discarding it.

picking up the next full bobbin case from the forward end of the magazine, and inserting said bobbin case into the looper in a position ready for sewing, the latter means comprising a guide pin secured in the shafting shaft, a sleeve surrounding the shifting shaft and provided with straight and helical recesses for guiding said guide pin, and a feeding sleeve with stepped diameters and a shifting member shaped similarly to the upper part of a bobbin case.

16. A device for` mechanically exchanging the bobbins in the looper of a sewing machine having a bed plate, a looper, and a looper shaft, said device comprising a magazine adapted to be lled with a plurality of bobbin cases with full bobbins, said magazine being provided with a safety bore and a safety groove and having a guide pin whose front end is shaped similarly to the retaining pin for the bobbin case in the looper of the machine, a shifting shaft shiftably and rotatably mounted on the bed plate, a grip claw carrier xedly mounted on said shaft and having a pair of 'grip claws, means for automatically and successively moving each of the bobbin cases in the magazine into a preparatory yielding position at the forward end thereof, and means for imparting a combination of axial and pivotal gnotions to said shifting shaft for lifting the empty bobbin case from its seat in the looper and discarding it, picking up the next full bobbin case from the forward end of the magazine, and insei-ting said bobbin case into the looper in a position ready for sewing, the latter means comprising a guide pin secured in the shifting shaft, and a sleeve surrounding the shifting shaft and provided with straight and helical recesses for guiding said guide pin.

17. A device for mechanically exchanging the bobbins in the looper of a sewing machine having a bed plate, a looper, and a looper shaft, said device comprising a magazine adapted to be ililed with a plurality of bobbin cases with full bobbins, a bipartite magazine holder secured to the bed plate of the machine and including a safety angle member' fastened to the movable part and a safety pin inserted in the fixed part thereof, said magazine having a guide pin whose front end is shaped similarly to the retaining pin for the bobbin casein the looper of the machine, a shifting shaft shiftably and rotatably mounted on the bed plate, a grip claw carrier xedly mounted on said shaft and having a pair of grip claws, means for automatically and successively moving each of the bobbin cases in the magazine into a preparatory yielding position at the -forward end thereof, and means for imparting a combination of axial and pivotal motions to said shifting shaft for lifting the empty bobbin case from its seat in the looper and discharding it, picking up the next full bobbin case from the forward end of the magazine, and inserting said bobbin case into the looper in a position ready for sewing, the latter means comprising a guide pin secured in the shifting shaft, and a sleeve surrounding the shifting shaft and provided with straight and helical recesses for guiding said guide pin.

18. A device for mechanically exchanging the bobbins in the looper of a sewing machine having a bed plate, a looper, and a looper shaft, said device comprising a magazine adapted to be filled with a plurality of bobbin cases with full bobbins, a bipartite magazine holder secured to the bed plate of the machine and including a safety angle 4member fastened to the movable part and a safety pin inserted in the fixed part thereof, a spring-urged releasing lever pivotally mounted on the magazine holder, said releasing lever engaging the cam of the shifting shaft and entering into the magazine in its swung-out position, through an opening in the magazine, said magazine having a guide pin whose front end is shaped similarly to the retaining pin for the bobbin case in the looper of the machine, a shifting shaft shiftably and rotatably mounted on the bed plate, and having a cam, a grip claw carrierfixcdly mounted on said shaft and having a pair of grip claws, means Afor automatically and successively moving each of the bobbin cases in the magazine into a preparatory yielding position at the forg ward end thereof, and means for imparting a combination of axial and pivotal motions to said shifting shaft for lifting the empty bobbin case from its seat in the looper and discharding it, picking up the next full bobbincase from the forward end of the magazine, and inserting said bobbin case into the looper in a position ready for sewing, the latter means comprising a guide pin secured in the shifting shaft, and a sleeve surrounding the shifting shaft and provided with straight and helical recesses for guiding said guide pin.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,087,703 Weitz Feb. 17, 1914 2,298,871 Cumfer Oct, 13, 1942 2,507,470 Hirsch May 9. 1950