VERTICAL FULL ROTATION HOOK

Abstract

 In order to prevent occurrence of thread breakage and incident looping, a spring member (50) is provided in an engaging recess of an inner shuttle (3) to resiliently bias an engaging portion (27a) of an engaging strip (27) of a bobbin case (5) on a downstream side of a direction of rotation (A) so as to suppress rattling and vibrations of the bobbin case (5) against the inner shuttle (3).

Description

Technical Field

[0001] The present invention relates to a vertical full rotation shuttle provided on a sewing machine.

Background Art

[0002] A vertical full rotation shuttle of the related art is described in, for example, Patent Literature 1. The vertical full rotation shuttle of the related art includes an outer shuttle fixed to a lower shaft of the sewing machine and having a hook portion, an inner shuttle retained in a state of being accommodated in the outer shuttle, a bobbin case removably mounted in the inner shuttle, and a bobbin around which a lower thread is to be wound and configured to be accommodated in the bobbin case.

[0003] When a sewing action of the sewing machine is started, the lower shaft is rotated in a predetermined direction of rotation about a horizontal axis of rotation, and a sewing needle repeats an action of moving toward and away from the axis of rotation along an axial line perpendicular to the axis of rotation of the lower shaft. A needle thread inserted through the sewing needle is caught by a hook portion and forms a needle thread loop. The needle thread loop moves along a surface of the inner shuttle and passes over the lower thread, which causes the needle thread to engage with the lower thread drawn out from the inner shuttle through a needle hole in a needle plate over a sewing machine head, and stitches are formed on an object to be sewed.

[0004] The inner shuttle includes a substantially cylindrical peripheral wall part, a bridge part that extends in one diameter direction so as to be connected to one end of the peripheral wall part in an axial direction thereof to form a bottom portion, a stud provided on the bridge part so as to extend upright toward the other end of the peripheral wall part in the axial direction, an outwardly extending flange that extends radially outward so as to be connected to the other end of the peripheral wall part in the axial direction, and a substantially C-shaped track projection that projects from an outer peripheral surface of the peripheral wall part and extends in a circumferential direction.

[0005] The peripheral wall part is provided with a needle location hole in which the sewing needle is inserted, and the inner shuttle is restricted from rotating by a retaining member which is connected to a proximal end thereof to a body of a sewing machine so that the needle location hole is always aligned with an axial line of the sewing needle and is prevented from rotating following the outer shuttle.

[0006] The bobbin case includes a cylindrical peripheral wall part that is fitted into the inner shuttle; an end wall portion provided so as to close an opening on one end side of the peripheral wall part; an engaging strip retained on the end wall portion so as to be movable in a direction of a diameter perpendicular to an axial line of the peripheral wall part, and also referred to as a latch; a latch spring that resiliently biases the engaging strip in one direction; and an operating lever that moves the engaging strip in the other direction against a spring force of the latch spring.

[0007] The engaging strip includes a strip-shaped base portion; and an engaging portion that is connected at substantially a right angle to one end in a longitudinal direction of the base portion, and the engaging strip is resiliently biased in the one direction by the latch spring in a direction of causing the engaging portion to project in a state in which the engaging portion protrudes from the peripheral wall part. The latch spring is formed of a compression coil spring, and is accommodated in a spring accommodating hole provided in the end wall portion in parallel to the longitudinal direction of the engaging strip.

[0008] The inner shuttle includes a peripheral wall part into which the peripheral wall part of the bobbin case can be approximately closely fitted; and a flange part that is connected to one end portion of the peripheral wall part on an opening end side, and the peripheral wall part and the flange part are provided with an engaging recess that extends across the peripheral wall part and the flange part so as to allow engagement of the above-described engaging portion. In a state in which the bobbin case is mounted in the inner shuttle, the engaging portion of the bobbin case fits into and engages with the engaging recess of the inner shuttle and the bobbin case is restricted from rotating with respect to the inner shuttle about an axial line of the inner shuttle.

Citation List

Patent Literature

[0009] Patent Literature 1: JP-Y2 61-14375(1986)

Summary of Invention

Technical Problem

[0010] In the related art described above, when the sewing action of the sewing machine is started, a reciprocal displacement action of the sewing needle and a rotational action of the outer shuttle cause the lower thread to be drawn out from the bobbin case in association with advance of the stitches during a sewing operation. Therefore, the bobbin is rotated in the bobbin case by a tensional force due to the feed of the lower thread. The bobbin case is restricted from rotating about the axial line of the inner shuttle as the engaging portion fits into and engages with the engaging recess of the inner shuttle as described above. However, since the bobbin case needs to be removably mountable with respect to the inner shuttle for replacing the bobbin, a clearance having a tolerance within a range of approximately 0.1 to 0.3 mm is provided between the engaging portion and the engaging recess in the direction of rotation thereof about the axial line of the inner shuttle. Therefore, there arises a problem of occurrence of vibrations in the bobbin case with respect to the inner shuttle mainly in the direction of rotation during a sewing operation, which may cause thread breakage or incidental looping due to changes in tension of an upper thread and a lower thread.

[0011] An object of the invention is to provide a vertical full rotation shuttle that is capable of preventing occurrence of thread breakage and incidental looping.

Solution to Problem

[0012] The invention provides a vertical full rotation shuttle including:

an outer shuttle fixed to a lower shaft which is rotated about an axis of rotation extending perpendicular to an axial line of a needle bar to which a sewing needle is attached, the outer shuttle including a hook portion having a distal end tapered toward a downstream side in a direction of rotation of the lower shaft;

an inner shuttle retained by the outer shuttle so as to rotate about the axis of rotation, the inner shuttle including a peripheral wall part having a cylindrical shape and provided with a needle location hole in which the sewing needle is inserted, and a flange part extending radially outward from one end of the peripheral wall part, an engaging recess being provided across the peripheral wall part and the flange part;

a bobbin case removably mounted in the inner shuttle, the bobbin case having an engaging strip that has a long plate shape and removably engages with the engaging recess with a clearance in the direction of rotation;

a spring member supported in the engaging recess and disposed in the clearance in a state in which the engaging strip engages with the engaging recess; and

a bobbin accommodated in the bobbin case, a lower thread being to be wound around the bobbin.

[0013] According to the invention, it is preferably that the spring member is a leaf spring.

[0014] According to the invention, it is preferably that the leaf spring includes a mounting portion that has a long plate shape and is fixed to the flange part on an upstream side of the direction of rotation with respect to the engaging recess; and a projection extending from one end in a longitudinal direction of the mounting portion into the clearance and projecting toward the downstream side in the direction of rotation.

Advantageous Effects of Invention

[0015] According to the invention, since the spring member is provided in the engaging recess of the inner shuttle, the engaging strip is resiliently biased by the spring member toward the downstream side in the direction of rotation in the state in which the bobbin case is mounted in the inner shuttle. Therefore, vibrations of the bobbin case with respect to the inner shuttle are restricted, and thus occurrence of thread breakage and incidental looping in association with changes in tension of the upper thread and the lower thread may be prevented.

Brief Description of Drawings

[0016] Other and further objects, features, and advantages of the invention will be more explicit from the following detailed description taken with reference to the drawings wherein:

FIG. 1 is a front view of a vertical full rotation shuttle 1 according to an embodiment of the invention;

FIG. 2 is a cross-sectional view of the vertical full rotation shuttle 1 taken along the line II-II in FIG. 1;

FIG. 3 is a front view of an inner shuttle 3;

FIG. 4 is a front view of the inner shuttle 3 in which a bobbin case 5 having a bobbin 4 accommodated therein is mounted;

FIG. 5 is a cross-sectional view taken along the line V-V in FIG. 3;

FIG. 6 is a cross-sectional view taken along the line VI-VI in FIG. 4;

FIG. 7 is an enlarged cross-sectional view of a portion near the spring member 50;

FIG. 8 is a side view of the inner shuttle 3;

FIG. 9 is a side view of the inner shuttle in which the bobbin case 5 is mounted;

FIG. 10 is a back view of the inner shuttle 3;

FIG. 11 is a back view of the inner shuttle 3 in which the bobbin case 5 is mounted;

FIG. 12 is an enlarged cross-sectional view of a portion near a spring member 50a of the inner shuttle 3 provided on a vertical full rotation shuttle 1b according to another embodiment of the invention;

FIG. 13 is an enlarged cross-sectional view of a portion near the spring member 50a of the inner shuttle in which the bobbin case 5 is mounted;

FIG. 14 is an enlarged cross-sectional view illustrating a portion near a spring member 50b of the inner shuttle provided on a vertical full rotation shuttle 1b according to still another embodiment of the invention; and

FIG. 15 is an enlarged cross-sectional view of a portion near the spring member 50b of the inner shuttle 3 in which the bobbin case 5 is mounted.

Description of Embodiments

[0017] Referring now to the drawings, a preferred embodiments of the invention will be described in detail.

[0018] FIG. 1 is a front view of a vertical full rotation shuttle 1 according to an embodiment of the invention, and FIG. 2 is a cross-sectional view of the vertical full rotation shuttle 1 taken along the line II-II in FIG. 1. FIG. 3 is a front view of an inner shuttle 3, and FIG. 4 is a front view of the inner shuttle 3 in which a bobbin case 5 having a bobbin 4 accommodated therein is mounted. FIG. 5 is a cross-sectional view taken along the line V-V in FIG. 3, and FIG. 6 is a cross-sectional view taken along the line VI-VI in FIG. 4.

[0019] The vertical full rotation shuttle 1 of the invention includes an outer shuttle 2, the inner shuttle 3, a bobbin 4, and a bobbin case 5. The outer shuttle 2 is fixed to a lower shaft 8 that is rotated in a direction indicated by an arrow A about an axis of rotation L2, which is perpendicular to an axial line L1 of a needle bar 7 on which a sewing needle 6 is detachably coaxially mounted. The outer shuttle 2 includes a tapered hook portion 9 having a distal end facing the downstream side in the direction of rotation A of the lower shaft 8.

[0020] The inner shuttle 3 is fitted into the outer shuttle 2, and a projection of a retaining member, which is not illustrated, fits into a recess 10 to restrict the inner shuttle 3 from rotating. The inner shuttle 3 includes a cylindrical peripheral wall part 12 provided with a needle location hole 11 through which the sewing needle 6 is inserted; a bottom portion 13 which is connected to other end portion of the peripheral wall part 12 in an axial direction thereof, extends in a direction of a diameter, and is also referred to as a bridge; a stud 14 provided perpendicularly upright from a center of the bottom portion 13 toward one end portion of the peripheral wall part 12 in the axial direction thereof; a flange part 15 which is connected to the one end portion of the peripheral wall part 12 in the axial direction thereof and is formed so as to extend radially outward; and a track projection 16 formed on the peripheral wall part 12 so as to project from an outer peripheral surface thereof.

[0021] The inner shuttle 3 is provided with an engaging recess 28 so as to extend across the peripheral wall part and the flange part 15.

[0022] The outer shuttle 2 and the inner shuttle 3 are formed, for example, of carburized carbon steel, and are provided with a hardness of 650 HV or more by thermal treatment. The bobbin 4 and the bobbin case 5 are formed of iron steel or stainless steel.

[0023] The flange part 15 is provided with the needle location hole 11 described above formed behind the recess 10, that is, on one end side of the peripheral wall part 12 in the axial direction thereof, and a lower thread guiding groove 35 that opens toward a fitting space which is defined by the recess 10 and to which the projection of the retaining member described above, which is not illustrated, fits from the downstream side in the direction of rotation A. The lower thread guiding groove 35 allows insertion of a lower thread 21 drawn out from between a peripheral wall part of the bobbin case 5 and a thread tensioning spring 33 provided on the peripheral wall part, so that the lower thread 21 passing through a needle hole 36 of a needle plate provided on a sewing machine head in a tensed manner is maintained in a state of being fitted in the lower thread guiding groove 35 and prevented from being protruded outside the recess 10 even though the lower thread 21 is loosened by a thread cutting action of a thread cutter, not illustrated, while leaving the recess 10 and coming apart completely at the time of passing over.

[0024] The bobbin case 5 is removably mounted in the inner shuttle 3, and the bobbin 4 having the lower thread 21, which is referred to as a bobbin thread, wound therearound is accommodated in the bobbin case 5. The bobbin case 5 is provided with a first notch 22 that allows downward movement of the sewing needle 6. The first notch 22 is formed in the peripheral wall part of the bobbin case 5 so as to extend in the axial direction and continues to a second notch 23. The bobbin case 5 is provided with a latch mechanism 25 that disengageably engages with the inner shuttle 3.

[0025] The inner peripheral portion 17 of the inner shuttle 3 is provided with a pair of projections 24. The projections 24 come into contact with an inner surface of the peripheral wall part of the bobbin case 5 that opposes via the second notch 23. In this configuration, when mounting the bobbin case 5 in the inner shuttle 3, insertion of the bobbin case 5 into the inner shuttle 3 is guided, and relative angular displacement between the bobbin case 5 and the inner shuttle 3 is restricted in cooperation with a latch mechanism 25.

[0026] The latch mechanism 25 includes an operating lever 26 and an engaging strip 27, restricts the angular displacement between the inner shuttle 3 and the bobbin case 5 by the engaging strip 27 engaging with an engaging recess 28 formed on the inner shuttle 3, and locks the bobbin case 5 with respect to the inner shuttle 3 and prevents the same from coming out therefrom. When replacing the bobbin 4, by releasing the locked state of the bobbin case 5 with respect to the inner shuttle 3, the latch mechanism 25 can release the bobbin case 5 from the inner shuttle 3.

[0027] In the vertical full rotation shuttle 1 as described above, the engaging strip 27 includes an engaging portion 27a that fits into and engages with the engaging recess 28 and a base portion 27b that has a long plate shape and is connected to the engaging portion 27a in a state in which the bobbin case 5 is mounted in the inner shuttle 3, and is formed into a substantially L-shape. The engaging portion 27a engages with the engaging recess 28 with a clearance in the direction of rotation. The flange part 15 is provided with a spring member 50 that resiliently biases the engaging portion 27a from an upstream side in the direction of rotation A toward the downstream side in the direction of rotation A by a spring force thereof in a state in which the engaging portion 27a engages with the engaging recess 28. The above-described spring member 50 is disposed in the clearance described above.

[0028] FIG. 7 is an enlarged cross-sectional view of a portion near the spring member 50, FIG. 8 is a side view of the inner shuttle 3, and FIG. 9 is a side view of the inner shuttle 3 in which the bobbin case 5 is mounted. FIG. 10 is a back view of the inner shuttle 3, and FIG. 11 is a back view of the inner shuttle 3 in which the bobbin case 5 is mounted. The spring member 50 includes a mounting portion 51 that has a long plate shape and is fixed to the upstream side in the direction of rotation A with respect to the engaging recess 28 of the flange part 15, and a projecting portion 52 that is bent from an end of the mounting portion 51 in the longitudinal direction at a substantially right angle, extends inward of the engaging recess 28, and is bent to form a projection projecting toward the downstream side (upward in FIG. 7) in the direction of rotation A. The spring member 50 is a leaf spring formed of a spring steel plate having a thickness on the order of 0.15 mm, for example.

[0029] As a method of fixing the mounting portion 51 to the flange part 15, the mounting portion 51 may be fixed to the flange part 15 by providing the flange part 15 with a mounting groove 53 extending in a direction of tangent line which is perpendicular to the axial line parallel to the longitudinal direction of the mounting portion 51 on an imaginary plane perpendicular to the axial line L2 of the lower shaft 8, and performing a swaging process in which both side portions 54a and 54b are swaged in directions close to each other in a state in which the mounting portion 51 is fitted into the mounting groove 53 so as to cause the mounting portion 51 to be tightly interposed between the side portions 54a and 54b.

[0030] In order to facilitate mounting and removal of the bobbin case 5 with respect to the inner shuttle 3, the projecting portion 52 includes a first portion 56 that inclines toward the downstream side in the direction of rotation A when viewing in a direction of insertion of the engaging portion 27a into the engaging recess 28 (rightward in FIG. 7) and a second portion 58 that extends via a peak portion 57 located on the downstream most side in the direction of rotation A and inclines toward the upstream side of the direction of rotation A toward the direction of insertion.

[0031] With the spring member 50 configured as described above, in a state in which the bobbin case 5 is mounted in the inner shuttle, the engaging portion 27a engages with the engaging recess 28, and the peak portion 57 of the spring member 50 resiliently abuts on the engaging portion 27a and is pressed by a constant pressing force from the upstream side in the direction of rotation. Accordingly, vibrations of the bobbin case 5 with respect to the inner shuttle 3 are restricted during a sewing operation, it is possible to prevent changes in tension of the upper thread and the lower thread in association with the vibrations and occurrence of thread breakage and incidental looping.

[0032] FIG. 12 is an enlarged cross-sectional view illustrating a portion near a spring member 50a of the inner shuttle 3 provided on a vertical full rotation shuttle 1a according to another embodiment of the invention, and FIG. 13 is an enlarged cross-sectional view of a portion near the spring member 50a of the inner shuttle 3 in which the bobbin case 5 is mounted. Portions corresponding to the above-described embodiment are denoted by the same reference numerals and overlapped description will be omitted.

[0033] The vertical full rotation shuttle 1a of this embodiment includes the outer shuttle 2, the inner shuttle 3, the bobbin 4, the bobbin case 5, and the spring member 50a. In the vertical full rotation shuttle 1a of this embodiment, the spring member 50a includes a mounting portion 61, a first portion 62 that has a substantially semi-cylindrical shape and is connected to the mounting portion 61 at one end portion in the longitudinal direction, and a second portion 63 that is connected to the first portion 62 and is inclined toward the upstream side in the direction of rotation A when viewing in the direction of insertion (rightward in FIG. 12) of the bobbin case 5. The spring member 50a is a leaf spring formed of a spring steel plate having a thickness on the order of 0.15 mm, for example. The mounting portion 61 is fixed to the flange part 15 in the groove 53 by a rivet 64.

[0034] The spring member 50a as described above presses the engaging portion 27a by the second portion 63 on the downstream side in the direction of rotation A, and also in the direction of insertion of the bobbin case 5. Therefore, rattling and vibrations of the bobbin case 5 about the axial line L2 may be suppressed, and rattling and vibrations of the same in the direction of the axial line L2 may also be suppressed. Accordingly, it is possible to prevent occurrence of thread breakage and incidental looping more certainly.

[0035] FIG. 14 is an enlarged cross-sectional view illustrating a portion near a spring member 50b of the inner shuttle 3 provided on a vertical full rotation shuttle 1b according to still another embodiment of the invention, and FIG. 15 is an enlarged cross-sectional view of a portion near the spring member 50b of the inner shuttle 3 in which the bobbin case 5 is mounted. Portions corresponding to the above-described embodiments are denoted by the same reference numerals and overlapped description will be omitted.

[0036] The vertical full rotation shuttle 1b of this embodiment includes the outer shuttle 2, the inner shuttle 3b, the bobbin 4, the bobbin case 5, and the spring member 50b. In the vertical full rotation shuttle 1b of this embodiment, the spring member 50b includes a mounting portion 71; a first portion 72 that is bent at an angle larger than a right angle, is connected to an end of the mounting portion 71 in the longitudinal direction, and extends into the engaging recess 28; and a projecting portion 73 that is connected to the first portion 72 and projects so as to protrude toward the downstream side in the direction of rotation A at a position close to an end on the downstream side in the direction of insertion of the bobbin case 5. The spring member 50b is a leaf spring formed of a spring steel plate having a thickness on the order of 0.15 mm, for example. The mounting portion 71 is fixed to the flange part 15 by a rivet 74.

[0037] By using the spring member 50b as described above as well, it is possible to prevent occurrence of thread breakage and incidental looping by eliminating changes in tension of the upper thread and the lower thread in the same manner as the embodiments described above.

[0038] The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description and all changes which come within the meaning and the range of equivalency of the claims are therefore intended to be embraced therein.

Reference Signs List

[0039] 

1, 1a, 1b:

Vertical full rotation shuttle

2:

Outer shuttle

3:

Inner shuttle

4:

Bobbin

5:

Bobbin case

6:

Sewing needle

7:

Needle bar

8:

Lower shaft

9:

Hook portion

10:

Recess

11:

Needle location hole

12:

Peripheral wall part

13:

Bottom portion

14:

Stud

15:

Flange part

16:

Track projection

17:

Inner peripheral portion

21:

Lower thread

22:

Notch

23:

Notch

24:

Projection

25:

Latch mechanism

26:

Operating lever

27:

Engaging strip

28:

Engaging recess

33:

Thread tensioning spring

35:

Lower thread guiding groove

36:

Needle hole

50, 50a, 50b:

Spring member

51, 61, 71:

Mounting portion

52, 57, 73:

Projecting portion

53:

Mounting groove

54a, 54b:

Side portion

56, 62, 72:

First portion

58, 63:

Second portion

Claims

1. A vertical full rotation shuttle comprising:

an outer shuttle fixed to a lower shaft which is rotated about an axis of rotation extending perpendicular to an axial line of a needle bar to which a sewing needle is attached, the outer shuttle including a hook portion having a distal end tapered toward a downstream side in a direction of rotation of the lower shaft;

an inner shuttle retained by the outer shuttle so as to rotate about the axis of rotation, the inner shuttle including a peripheral wall part having a cylindrical shape and provided with a needle location hole in which the sewing needle is inserted, and a flange part extending radially outward from one end of the peripheral wall part, an engaging recess being provided across the peripheral wall part and the flange part;

a bobbin case removably mounted in the inner shuttle, the bobbin case having an engaging strip that has a long plate shape and removably engages with the engaging recess with a clearance in the direction of rotation;

a spring member supported in the engaging recess and disposed in the clearance in a state in which the engaging strip engages with the engaging recess; and

a bobbin accommodated in the bobbin case, a lower thread being to be wound around the bobbin.

2. The vertical full rotation shuttle according to claim 1, wherein the spring member is a leaf spring.

3. The vertical full rotation shuttle according to claim 2, wherein the leaf spring includes a mounting portion that has a long plate shape and is fixed to the flange part on an upstream side of the direction of rotation with respect to the engaging recess; and a projection extending from one end in a longitudinal direction of the mounting portion into the clearance and projecting toward the downstream side in the direction of rotation.

Drawing