US2813500A - Bobbin-cases for sewing machines - Google Patents

Description

Nov. 19,1957 H. J. GOOSMAN ETAL 2,313,500

BOBBIN-CASES FOR SEWING MACHINES Filed June 26, 1951 INVEN T0128 Werbe'rt g. oosmau and @avid @gmessew ATTORNEY United States Patent (Y This application relates to a bobbin-case for a sewing machine and moreparticularly to a round bobbin-case of the two-section type, the base-section of which is journaled in a rotary, loop-taker of a lock-stitch sewingmachine.

An object of this invention is to provide' abobbin-casewhichcan be easily manufactured. and assembled.

Another objectof the invention is to provide a.bbbincase. rotation-restraining finger which is easily manufactured and attached to the bobbin-case- A still, further object of the invention is. to provide a bobbin-case cap-section having simple, smooth contours on its face portion which will permit the needle-threadloop to pass freely over the bobbin-case.

Another. object-of the invention is to provide a latch mechanism to. secure a bobbin-case cap-section and basesection together;

with thelabove. andother objects'in view, the invention comprises the" devices, combinations and arrangements of parts; hereinafter setforth. and illustrated in the accompanying drawings of a preferred embodiment of the invention, from which the several features of the invention and the advantages attained thereby will be readily understood by those skilled in the art.

In the accompanying drawings- Fig. 1 is a view in front end elevation of the bobbin-case.

Fig. 2 is a view in side elevation of the bobbin-case.

Fig. 3 is a view in rear end elevation of the bobbin-case.

Fig. 4 is an enlarged sectional view of the bobbin-case taken on line 44 of Fig. 1.

Fig. 5 is an exploded view of the two sections of the bobbin-case.

Fig. 6 is an exploded view of the bobbin-case base and the position-finger.

Fig. 7 is a partial sectional view of the bobbin-case taken on line 7--7 of Fig. 1.

Referring more specifically to the drawings, the bobbincase is shown as comprising two major parts, a basesection 10 and a cap-section 11. The base-section 10 is formed from a flat disc 12 which is of such a thickness that its peripheral edge will function properly as a bearing-rib in the usual, well known, bearing race (not shown) of a rotary loop-taker. The disc 12 is provided with a central fiat-sided opening 13 which receives a flat-sided pilot 14, Fig. 6, on a bobbin-post 15. A radial groove or recess 16 extends outwardly in the rear face of the disc 12 from the central opening 13 and terminates in a rectangular aperture 17 in the disc near its periphery. The smooth periphery of the disc 12 is broken to form a needle-thread-loop detaining spur 18 and a thread-clearance gap 18 terminated by a shoulder 18". A bent rotation-restraining or position-finger 19 extends through the rectangular aperture 17 in the disc and is provided with a shank portion 20 which is fitted in the radial groove 16. The thickness of the position-finger shank 20 and the depth of the groove 16 are substantially equal, so that the exposed surface of the shank portion 20 is approximately flush with the rear face of the disc 12. A screw 21 passes through a countersunk hole 22 in the shank portion 20 to enter a threaded 2,813,500 Patented Nov. 119,

hole 23 in the pilot end portion of the post 15. Thus, the screw 21 secures both the post 15 and the position-finger 19 to the disc 12. A second screw 24 passes through a clearance hole 25 in the disc 12 and is received in a thread ed hole 26 in the'shank of theposition-finger to hold the outer end of the shank portion 20 firmly against the disc. A plurality of apertures 20' are preferably formed in the disk. 12. to reduce its weight.

The cup-shaped bobbin-case cap-section 11 is provided with an: axially inwardly extending sleeve 27 which is journaled on the bobbin-post 1 5- and provided with a slot 27". The cap-section 11 carries a latch mechanism which secures it to the base-section 101 The latch mechanisnr comprises a lever 28 provided with a heel portion 28' and a hook portion 29 at one end, the lever being pivotally se cured to the cap-section by meansof a pivot-pin 30. An opening. 31 in the end wall of the cap-section 11 provides" clearance space for a small coil spring 32which is wound around the pivot-pin 30. One end of the spring 32' passes" through a groove 33 and is anchored ina-hole 34 in the lever 28, while the other end of the spring is positioned in a hole 35 in the cap section 11. The spring 32 normally urges the latch-lever 28 to the latch-closed position, shown in Fig. 1. When the latch-lever 28 is in the latched-closed position, the hook portion 29 is positioned in an axial slot 36 in the bobbin-post 15 and engages one wall of a transverse opening 37 formed in the post 15 and, thus, holds the cap-section securely in place on the post 15. The right and bottom portions 38 and 39 of the cap-section, as viewed in Fig. l, are bevelled inorder to permit a limb of the needle-thread-loop to pass over the exposed'face of the cap-section with aminimum of effort. The usual bobbin'thread: tension spring 40 is fastened to the side wall of the cap-section 11 by a screw 41 and an adjusting screw 42. A position finger gap 43 is formed in the wall of the bobbin-case cap section 11 to receive the position finger 19.

In view of the above description, it is believed that the advantages of this invention will be readily understood. In previous types of round bobbin-cases of the two-section type, such as that shown in the U. S. Patent No. 2,015,472, dated Sept. 24, 1935, it is necessary to machine the entire base-section including the position-finger and the center spindle from a single piece of material. This type of construction is essentially wasteful of material and, due to the integral position-finger and its supporting wall, makes it very difficult to machine the peripheral edge of the basesection, which forms the base-section bearing ridge, to the requisite close dimensions. In the construction according to the invention the bobbin-case base-section comprises three separate parts, the flat'disc 12, the position finger 19,

and the post 15. Thus, the flat disc 12 can be easily machined and ground to the exact thickness required for the bearing surface at its outer periphery. The positionfinger 19 and the bobbin-post 15 are formed from small pieces of material and are easily attached to the disc as previously described. 1

The construction of the cap-section 11 provides a simple and effective device which is readily removable for replacement of the bobbin. In previous bobbin-cases, such as the case shown in the above mentioned Patent No. 2,- 015,472, the exposed face of the bobbin-case presents many slots and ridges over which the needle-thread must pass. These slots and ridges offer considerable resistance to the passage of the thread 2 and must be carefully smoothed and polished. The bobbin-case cap-section 11, constructed according to the invention, presents a smooth exposed face across which the thread can easily pass. The bevelled edge and bottom portions of the cap-section permit the needle thread to slide freely over the face of the cap-section from right to left, as viewed in Fig. 1. Further, the latch-lever 28 lies flush with the face of the cap section 11 and the latch-spring 32 lies below the surface of the cap section so that there is no obstruction to the passage of the needle thread loop. The bobbin-case latchlever 28 functions to hold the cap-section 11 securely on This pivots the lever 28 about the pin 30 and releases the 15. The cap from the post The heel portion 28' passes and frictionally engages the hook 29 from engagement with the post section 11 may then be withdrawn axially 15 to replace the bobbin. through the slots 36 and 2'7 inner surface of the tubular portion of the usual, well known bobbin (not shown), so that the bobbin is removed with the cap-section 11 when the lever 28 is lifted and the cap-section withdrawn.

Having thus set forth the nature of the invention, what we claim herein is:

1. A sewing machine bobbin-case base comprising a fiat disc having a groove in one face joining an aperture and a central opening formed in said disc, a detachable position finger extending through said aperture and having a shank portion positioned in said groove, a detachable slotted post positioned in said central opening, and means securing said post and said shank portion to said disc.

2. A sewing machine bobbin-case comprising a basesection and a cap-section, said base section including a flat circular disc having a groove in its rear face joining a central opening and an aperture formed in said disc, a

bobbin-case position-finger extending through said aperture and having a shank portion positioned in said groove, a slotted axially extending post positioned in said central opening, one attaching means fastening said shank and said post to said disc, a cup-shaped bobbin-case cap-section, a bobbin-supporting sleeve concentric with said post and carried by said cap-section, and a latch-lever carried by said cap-section and releasably engaging said axially extending post.

3. A sewing machine bobbin-case base comprising a fiat circular disc having a rectangular aperture near its periphery and a central opening connected by a groove in its rear face, a detachable slotted bobbin-post positioned in said central opening, a detachable position-finger ex tending through said aperture and having a shank portion fitted in said groove, means fastening said post and said shank to said disc, a cup-shaped bobbin-case having a central sleeve concentric with said post, said bobbin-case being formed with beveled portions on its outer face, and

a spring-biased latch-lever pivotally carried by said bobbincase and normally engaging said post.

4. A sewing machine bobbin-case base for rotary loop takers comprising a flat disc provided in one face thereof,

with a radially extending recess terminating at one end in an opening in said disc, said disc having a circular periphery forming a bearing-rib cut away to provide a threadclearance gap and a thread-detaining spur, a detachable base-section positioning finger extending through said opening and having a shank seated in said recess, and means securing said positioning-finger to said disc.

References Cited in the file of this patent UNITED STATES PATENTS 2,015,472 Goosman Sept. 24, 1935 2,088,560 Parry July 27, 1937 2,212,475 Karle Aug. 20, 1940

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