US3530811A - Bobbin case tension spring - Google Patents

Bobbin case tension spring Download PDF

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Publication number
US3530811A
US3530811A US819213A US3530811DA US3530811A US 3530811 A US3530811 A US 3530811A US 819213 A US819213 A US 819213A US 3530811D A US3530811D A US 3530811DA US 3530811 A US3530811 A US 3530811A
Authority
US
United States
Prior art keywords
bobbin
spring
thread
lip
bobbin case
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US819213A
Other languages
English (en)
Inventor
Ludwig J Kuhar
Joseph J Dolney
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
SSMC Inc
Original Assignee
Singer Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Singer Co filed Critical Singer Co
Application granted granted Critical
Publication of US3530811A publication Critical patent/US3530811A/en
Anticipated expiration legal-status Critical
Assigned to SSMC INC., A CORP. OF DE reassignment SSMC INC., A CORP. OF DE ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: SINGER COMPANY, THE
Expired - Lifetime legal-status Critical Current

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Classifications

    • D—TEXTILES; PAPER
    • D05—SEWING; EMBROIDERING; TUFTING
    • D05B—SEWING
    • D05B57/00—Loop takers, e.g. loopers
    • D05B57/08—Loop takers, e.g. loopers for lock-stitch sewing machines
    • D05B57/10—Shuttles
    • D05B57/14—Shuttles with rotary hooks
    • D—TEXTILES; PAPER
    • D05—SEWING; EMBROIDERING; TUFTING
    • D05B—SEWING
    • D05B73/00—Casings
    • D05B73/04—Lower casings
    • D05B73/12—Slides; Needle plates

Definitions

  • Robert E. Smith ABSTRACT A bobbin case for use in a sewing machine comprising a cup-shaped body including a cylindrical outer wall and a substantially circular end face.
  • a bobbin thread tension spring is adjustably secured to the outer wall.
  • An overhanging arcuate lip projecting radially from the periphery of the end face overlays the spring to provide a smooth snag-free surface over which the needle thread loop can pass.
  • a finger extends from an edge of the spring and folds over the spring to abut the lip thus preventing bobbin thread from becoming entrapped under the lip,
  • This invention relates to lock stitch sewing machines, and more particularly, to a bobbin case therefor.
  • the loop of needle thread smoothly glides over the lip onto the surface of the bobbin case face without becoming snagged on the spring or its securing means. It has been found, however, that the bobbin thread, when it is loose such as for instance prior to the making of the first stitch, can be carried down by the needle thread limb and tends to get trapped beneath the lip.
  • One disadvantage of such trapping of the bobbin thread is that it may prevent the needle thread loop from drawing the bobbin thread into the work to form the stitch. This problem is amplified in cyclic sewing machines since the bobbin thread is cut at the end of each cycle and the cut end must be picked up by the loop of needle thread to make the first stitch of the following cycle.
  • a second disadvantage of such trapping of the bobbin thread is that it can drastically change the tension which is applied to the bobbin thread thus causing a detrimental effect on the appearance of the stitching. It is, therefore, an object of this invention to provide in bobbin cases of this type a means for preventing entrapment of bobbin thread beneath the lip.
  • It is a more specific object of this invention to provide a bobbin case comprising a tension spring, an overhanging lip formed on the bobbin case to overlay the spring, and a finger extending from an edge of the spring and folding over the body of the spring to abut the lip so as to prevent bobbin thread from becoming trapped beneath the lip.
  • FIG. 1 represents a front elevational view of a cyclic lock stitch sewing machine loop taker having a bobbin case of this invention and including portions of the sewing machine,
  • FIG. 3 is an enlarged perspective of the assembled bobbin case of this invention with the bobbin inserted and showing the position of the bobbin thread prior to the formation of the first stitch,
  • FIG. 5 is an enlarged fragmentary cross-sectional view of the bobbin case taken substantially along line 5-5 of FIG. 4 and showing a portion of the finger in phantom, and
  • FIGS. 2-6 of the drawing will be explained as embodied in a cyclical lock stitch sewing machine of which FIG. 1 illustrates the stitch forming instrumentalities. Only those parts of the sewing machine and stitch forming instrumentalities which will aid in understanding this invention will be described herein. For a more detailed description reference may be had to US. Pat. Nos. 2,990,794 and 2,968,269.
  • a rotary loop taker l cooperates with a reciprocating needle 2 to draw out a loop of needle thread N and to carry the needle thread loop about a mass of threadB stored on a bobbin 3 within a bobbin case 4 which bobbin case is supported in nonrotating relationship within the loop taker.
  • the loop of needle thread is taken by the loop seizing beak 5 of the loop taker and passed around the bobbin case; the front limb 6 of the needle thread passing over the bobbin case.
  • the bobbin thread is enclosed by the needle thread loop in the usual manner and when the needle thread loop is drawn up into a work fabric the bottom thread concatenated therewith is also drawn up and the stitch is tightened and set.
  • the bobbin case 4 of this invention comprises a cylindrical outer wall 9 and a circular end face 10, which together form a cup-shaped body of the bobbin case. Located on the face 10 is a pair of raised shoulders I1 and 12 which define a groove 13.
  • a flat thread tension leaf-spring 15 is provided on the cylindrical outer wall 9 so as to properly tension the bobbin thread passing through the bobbin case and between the forked end 16 of the spring.
  • the spring includes two apertures 17 and 18 into which screws 19 and 20 respectively fit.
  • the cylindrical wall 9 includes threaded apertures 21 and 22 which threadedly receive the screws 19 and 20, respectively, to secure the spring to the cylindrical wall. The tension applied by the spring can be adjusted by tightening or loosening the screw 20.
  • an overhanging lip 23 which is formed continuous with the end face 10 and projecting radially from the periphery thereof arcuately sloping toward the outer wall 9 to overlay a portion of the spring 15.
  • the upper surface of the lip is highly polished to provide a smooth transitional surface for the passage of the limb 6 of needle thread from the loop taker onto the highly polished surface of the shoulders 11 and 12.
  • the smoothly arcuate end of the lip ensures that the limb of needle thread will not snag on the spring as the limb rides onto the end face shoulders.
  • the cutout 24 in the lip provides a clearance for insertion of a screwdriver to adjust screw 20.
  • the bobbin thread B passes within the case from the bobbin and then out through an aperture 26 beneath the spring 15. The thread is drawn along the cylindrical wall 9 between the fork 16 of the spring and over the hole 27, down through an aperture 28 into the case, and then up through an aperture 29.
  • the threaded bobbin case is clearly shown in FIG. 3 with the bobbin thread shown positioned as it would be prior to a needle thread loop capturing it at the beginning of the first stitch of a stitching cycle.
  • the present invention provides a finger 30 integral with the spring.
  • the finger extends from the edge of the spring remote from the lip and folds or bends over the main body of the spring into abutting relationship with the lip.
  • the tip 31 of the finger is of arcuate shape to conform to the contour of the lip so as to prevent any protrusions thereof from interfering with the needle thread as it rides across the lip. It can be clearly seen that the finger closes off the path of the bobbin thread to beneath the lip and thus prevents the entrapment problem.
  • the bobbin thread passes over the upper surface of the finger and is available to be drawn up to the work by the needle thread loop.
  • a bobbin case having a cup-shaped body comprising a cylindrical outer wall and a substantially circular end face, a thread tension leaf-spring secured to the outer surface of the outer wall and contiguous with a portion thereof, a lip formed on the periphery of the end face overlaying the spring, and a finger extending from the edge of the spring opposite said lip and folded over the main body thereof into abutting relationship with said lip.
  • the lip comprises an arcuate projection extending radially from the periphery of the end face to overlay the spring, the lip being formed to provide a smooth transition with the end face ad jacent the periphery.
  • a bobbin case for use in a two thread lock stitch sewing machine having a loop taker comprising a cup-shaped body including a cylindrical outer wall and a substantially circular end face, a bobbin thread tension spring adjustably secured to the outer surface of the outer wall, means for adjustably securing the spring to said wall, an overhanging lip formed continuous with said end face projecting radially from the periphery thereof and sloping toward said wall, said lip overlaying the spring to provide a smooth transitional surface for the passage of needle thread from the loop taker onto the surface of the end face, and means on the spring for preventing entrapment of bobbin thread beneath the overhanging lip.
  • said means for preventing entrapment comprises a finger integral with the spring extending from the edge thereof opposite said lip and folded over the body of the spring to abut the lip.

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  • Engineering & Computer Science (AREA)
  • Textile Engineering (AREA)
  • Sewing Machines And Sewing (AREA)
US819213A 1969-04-25 1969-04-25 Bobbin case tension spring Expired - Lifetime US3530811A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US81921369A 1969-04-25 1969-04-25

Publications (1)

Publication Number Publication Date
US3530811A true US3530811A (en) 1970-09-29

Family

ID=25227503

Family Applications (1)

Application Number Title Priority Date Filing Date
US819213A Expired - Lifetime US3530811A (en) 1969-04-25 1969-04-25 Bobbin case tension spring

Country Status (5)

Country Link
US (1) US3530811A (de)
DE (2) DE2019615A1 (de)
FR (1) FR2045491A5 (de)
GB (1) GB1254657A (de)
SE (1) SE353109B (de)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20030167989A1 (en) * 2000-08-31 2003-09-11 Lee Sang Cheol Bobbin case of rotary shuttle device for sewing machine
US20170022644A1 (en) * 2015-07-24 2017-01-26 Janome Sewing Machine Co., Ltd. Bobbin holder
USD953010S1 (en) * 2018-12-04 2022-05-31 Cm Cerliani S.R.L. Bobbin case

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20030167989A1 (en) * 2000-08-31 2003-09-11 Lee Sang Cheol Bobbin case of rotary shuttle device for sewing machine
US6776111B2 (en) * 2000-08-31 2004-08-17 Kobest Co., Ltd. Bobbin case of rotary shuttle device for sewing machine
US20170022644A1 (en) * 2015-07-24 2017-01-26 Janome Sewing Machine Co., Ltd. Bobbin holder
US9982376B2 (en) * 2015-07-24 2018-05-29 Janome Sewing Machine Co., Ltd. Bobbin holder
USD953010S1 (en) * 2018-12-04 2022-05-31 Cm Cerliani S.R.L. Bobbin case

Also Published As

Publication number Publication date
DE7015021U (de) 1970-10-22
FR2045491A5 (de) 1971-02-26
GB1254657A (en) 1971-11-24
DE2019615A1 (de) 1971-02-25
SE353109B (de) 1973-01-22

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Legal Events

Date Code Title Description
AS Assignment

Owner name: SSMC INC., A CORP. OF DE, CONNECTICUT

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:SINGER COMPANY, THE;REEL/FRAME:005041/0077

Effective date: 19881202