Full rotation hook

Abstract

To provide a full rotation hook capable of improving durability.SOLUTION: A full rotation hook 1 comprises: an inner hook 5 having a rail 30 extending in a circumferential direction at a periphery; a groove 25 allowing the rail to be fitted into an inner peripheral part; and an outer hook 4 having a pointed end 8 for capturing a needle yarn fed by a sewing needle 2. The outer hook 4 is driven to rotate around rotation axis in a state where rotation of the inner hook 5 is inhibited. The outer hook 4 comprises: a bottom 31 having an inlet port 44 into which compressed air is fed; and a peripheral wall part 43 having a plurality of outlet ports 45a, 45b that open toward a space 16 of the groove 25. A vent hole 24 for communicating the inlet port and the outlet ports is provided on the bottom 31 and the peripheral wall part 43. The rail 30 has a cutout part 54 that opens outward in a radial direction.SELECTED DRAWING: Figure 8A

Description

[Technical Field]

[0001] The present invention relates to a full rotary hook, such as a vertical full rotary hook and a horizontal full rotary hook. [Background technology]

[0002] A conventional full rotary hook is described, for example, in Patent Document 1. Patent Document 1 describes a hook for a sewing machine in which a rail made of high-density polyethylene containing a lubricant, liquid crystal polymer, or a material made by mixing aluminum alloy powder with alumina powder is detachably fixed to the outer periphery of the hook body, thereby reducing the rotational torque of the hook and enabling the hook to rotate stably at high speeds.

[0003] Another prior art is described, for example, in Patent Document 2. The full rotary hook in Patent Document 2 includes an inner hook having a rail that extends in the circumferential direction and is made of a heat-resistant synthetic resin, and an outer hook having a raceway into which the rail is fitted and whose inner peripheral surface is covered with a coating made of DLC (diamond-like carbon). By adopting this configuration, the full rotary hook in Patent Document 2 is said to be able to prevent seizure between the rail and the raceway groove and to perform smooth sewing even when the contact area between the rail and the raceway groove becomes hot due to frictional heat, as the outer hook rotates at a high speed of about 8,000 rpm to 12,000 rpm. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 6-238084 [Patent Document 2] Japanese Patent Application Laid-Open No. 2008-295966 Summary of the Invention [Problem to be solved by the invention]

[0005] In the prior art of Patent Document 1, the inner hook rail is made of a material such as high-density polyethylene containing a lubricant, liquid crystal polymer, or aluminum alloy powder mixed with alumina powder. In the prior art of Patent Document 2, the inner hook rail is made of a heat-resistant synthetic resin. While the prior arts of Patent Documents 1 and 2 can prevent seizure between the rail and the track groove caused by high-speed rotation of the outer hook, they suffer from the problem of frequent rail replacement and low durability due to wear of the rail caused by friction between the outer and inner hooks.

[0006] SUMMARY OF THE INVENTION An object of the present invention is to provide a highly durable full-rotation hook. [Means for solving the problem]

[0007] The present invention relates to a rotating shaft having an inner casing having a rail extending in a circumferential direction on an outer periphery thereof, The sewing machine includes an outer hook having a track groove in its inner periphery into which the rail fits and a point for capturing the needle thread supplied by the sewing needle, the outer hook being a fully rotating hook that is driven to rotate about a rotation axis while the inner hook is prevented from rotating, the outer casing includes a bottom portion having an inlet through which compressed air is supplied, and a peripheral wall portion having a plurality of outlets that open toward the space of the raceway groove, The bottom portion and the peripheral wall portion are provided with vent holes that communicate with the inlet and the outlet, The rail is a full-rotation hook characterized by having a notch that opens outward in the radial direction.

[0008] In addition, the rotary hook of the present invention is characterized in that the cutout portion has a first surface extending radially outward and a second surface opposing the first surface.

[0009] The full rotary hook of the present invention is characterized in that the first surface is positioned facing the downstream side of the outer rotary hook in the rotation direction.

[0010] The full rotary hook of the present invention is characterized in that the first surface is bent in a convex shape toward the upstream side in the rotation direction of the outer hook.

[0011] The rotary hook of the present invention is characterized in that the first surface and the second surface are spaced apart in the circumferential direction.

[0012] The full rotary hook of the present invention is characterized in that the second surface extends radially outward.

[0013] Further, in the rotary hook of the present invention, the plurality of outlets include a first outlet and a second outlet, The air vents are characterized by having a first air vent that communicates with the inlet and the first outlet, and is provided on the side where the tip is located with respect to an imaginary plane that includes the rotation axis and on which the tip of the tip is in contact, and a second air vent that communicates with the inlet and the second outlet, and is provided on the opposite side of the imaginary plane from the side where the tip is located.

[0014] The fully rotating hook of the present invention is characterized in that a recessed groove extending in the circumferential direction is provided on the bottom surface of the raceway groove.

[0015] The full rotary hook of the present invention is characterized in that it is a vertical full rotary hook.

[0016] The full rotary hook of the present invention is characterized in that it is a horizontal full rotary hook.

[0017] Furthermore, the present invention provides a fully rotating hook, wherein the outer peripheral surface of the rail and the inner peripheral surface of the rail groove are spaced apart from each other by a gap of 0.04 mm or more and 0.08 mm or less in a direction perpendicular to the rotation axis.

[0018] The full-rotation hook of the present invention is characterized in that the rail is made of a heat-resistant synthetic resin. [Effects of the Invention]

[0019] According to the present invention, the hook is provided with an air vent opening facing the track groove, and compressed air is supplied to the air vent. The rail of the hook inserts into the track groove of the hook, and compressed air is supplied between the track and the track groove through the air vent. When the hook is rotated about its rotation axis, compressed air passes between the track groove and the rail, reducing frictional resistance caused by contact between the track groove of the hook and the rail of the hook insert, thereby reducing the rotational resistance of the hook. In addition, the compressed air passes through a notch opening radially outward in the rail, suppressing rotation of the hook insert due to rotation of the hook, allowing the needle thread loop captured by the point of the hook to smoothly pass through the hook stopper where the hook and the hook abut. This prevents seizure between the rail and the track groove, even when the hook is rotated at high speed, resulting in smooth thread threading and the formation of a high-quality seam. Therefore, unlike the prior art, there is no need to use lubricating oil, and therefore the upper thread, lower thread, and sewing material will not be soiled by the lubricating oil, thereby improving the efficiency of the sewing work.

[0020] Furthermore, according to the present invention, the cutout portion has a first surface and a second surface, and therefore the compressed air flow passing through the cutout portion abuts against the first surface and the second surface, suppressing co-rotation of the inner hook and the outer hook as they rotate, facilitating and smoothing the thread passing operation and improving the stitching quality.

[0021] Furthermore, according to the present invention, the first surface of the notch is located downstream in the rotation direction of the rotary hook, so that the compressed air flow passing through the notch acts more effectively on the first surface and can resist the rotational force of the rotary hook. This makes it possible to cancel out the torque acting on the rotary hook as the rotary hook rotates, thereby further increasing the force resisting the rotational force of the rotary hook and reducing stress on the upper thread passing between the rotary hook and the abutting rotary hook stopper.

[0022] Furthermore, according to the present invention, the first surface of the notch is bent convexly toward the upstream side in the rotation direction of the rotary hook, which increases the area with which the compressed air flow passing through the notch abuts, thereby further increasing the force resisting the rotational force of the rotary hook. This further reduces stress on the upper thread passing between the rotary hook and the abutting rotary hook stopper.

[0023] Furthermore, according to the present invention, the first surface and the second surface are spaced apart in the circumferential direction, so that a sufficient flow rate of compressed air passes through the cutout portion and the compressed air is supplied to the gap between the rail and the rail groove, reducing contact between the rail and the rail groove and suppressing friction between the rail and the rail groove when the outer hook rotates.

[0024] Furthermore, according to the present invention, since the second surface extends radially outward, it is possible to suppress turbulence in the airflow of compressed air passing through the cutout portion.

[0025] According to the present invention, the air holes include a first air hole and a plurality of second air holes, and therefore, with respect to an imaginary plane that includes the rotation axis of the shuttle hook and on which the tip of the blade contacts, the amount of air ejected from the plurality of second air holes on the opposite side to the side including the blade tip is greater than the amount of air ejected from the first air hole on the side including the blade tip, and therefore the shuttle hook can be pressurized against the shuttle hook by the air pressure ejected from each second air hole. Therefore, compressed air is ejected from the first air hole on one side to the rail, and compressed air is ejected from each second air hole on the other side, which stabilizes the rotation of the shuttle hook and stably supports the needle thread captured by the tip of the blade tip through each second air hole in the shuttle hook. Therefore, when sewing, the needle thread caught by the tip of the outer hook forms a needle thread loop and passes over the outer surface of the inner hook, changes in the tension of the needle thread are suppressed, allowing the thread to pass over smoothly and forming high-quality stitches without thread breakage.

[0026] According to the present invention, since the bottom surface of the raceway groove is provided with a recessed groove, the compressed air supplied from the vent hole into the raceway groove is guided in the circumferential direction by the recessed groove, and the compressed air is supplied almost uniformly in the circumferential direction to the gap between the raceway groove and the rail, preventing contact between the raceway groove and the rail. This reduces noise such as hook noise generated during sewing, reduces heat generation due to frictional contact between the rail and the raceway groove, prevents seizure due to high-speed rotation of the shuttle hook, and improves the durability of the shuttle hook and the shuttle hook.

[0027] According to the present invention, the full-rotating hook is configured as a vertical full-rotating hook, so that even when the outer hook is rotated at high speed, the heat of the rail and the rail groove is discharged to the outside by the cooling effect of the compressed air flowing between the rail and the rail groove, preventing seizure and enabling the stable formation of high-quality seams, thereby improving the production efficiency of the sewn material.

[0028] According to the present invention, the fully rotating hook is configured as a horizontal fully rotating hook. Therefore, even when the outer hook is rotated at high speed, the cooling effect of the compressed air flowing between the rail and the rail groove prevents the temperature of the rail and the rail groove from rising, allowing high-quality seams to be formed stably at high speed, thereby improving the production efficiency of the sewn material.

[0029] According to the present invention, the outer peripheral surface of the rail and the inner peripheral surface of the rail groove are separated by a gap of 0.04 mm or more and 0.08 mm or less in the direction perpendicular to the axis of rotation, so that the compressed air ejected from the air holes reliably forms an air layer in the gap between the rail and the rail groove, preventing the rail and the rail groove from coming into contact with each other with excessive contact pressure, preventing seizure between the rail and the rail groove even when the outer hook is rotated at high speed, and providing a fully rotating hook that is free from oil stains due to lubricating oil. [Brief explanation of the drawings]

[0030] [Figure 1] 1 is a cross-sectional view showing a state in which a vertical rotary hook 1 according to an embodiment of the present invention is attached to a lower shaft 3. FIG. [Figure 2] FIG. 2 is an exploded perspective view of the vertical full rotation hook 1. [Figure 3] FIG. [Figure 4] FIG. 2 is a cross-sectional view of the outer hook 4. [Figure 5] FIG. 5 is an enlarged view of section V of FIG. [Figure 6] 10 is an enlarged cross-sectional view showing a state in which a rail 30 of an inner hook 5 is fitted into a track groove 25 of an outer hook 4. FIG. [Figure 7] FIG. 8 is an enlarged view of section VIII of FIG. 7. [Figure 8A] FIG. 2 is a front view showing a state in which the vertical full rotation hook 1 is placed at the first rotation position. [Figure 8B] FIG. 2 is a front view showing a state in which the vertical full rotation hook 1 is disposed at the second rotation position. [Figure 8C] FIG. 2 is a front view showing a state in which the vertical full rotation hook 1 is disposed at a third rotation position. [Figure 9] FIG. 2 is an enlarged front view of the vicinity of the notch 54. [Figure 10] FIG. 2 is an enlarged perspective view of the vicinity of a cutout portion 54. [Figure 11] FIG. 5 is an enlarged plan view showing a modified example 54a of the cutout portion; [Figure 12] FIG. 12 is an enlarged perspective view of a cutout portion 54a shown in FIG. [Figure 13] FIG. 10 is a front view showing an outer hook 4a according to another embodiment of the present invention. [Figure 14] FIG. 10 is a perspective view showing the appearance of a horizontal full rotation hook 51 according to another embodiment of the present invention. [Figure 15] FIG. 2 is an exploded perspective view of the horizontal full rotation hook 51. [Figure 16] FIG. [Figure 17] FIG. 2 is a partially cutaway front view of the horizontal full rotation hook 51. [Figure 18] FIG. 10 is an enlarged plan view showing another modified example of the notch portion. [Figure 19] FIG. 10 is an enlarged plan view showing yet another modified example of the notch portion. DETAILED DESCRIPTION OF THE INVENTION

[0031] A vertical full-rotating hook 1 according to one embodiment of the present invention will be described with reference to FIGS. 1 to 8. FIG. 1 is a cross-sectional view showing the vertical full-rotating hook 1 according to one embodiment of the present invention attached to the lower shaft 3. FIG. 2 is an exploded perspective view of the vertical full-rotating hook 1. FIG. 3 is a front view of the shuttle hook 4. FIG. 4 is a cross-sectional view of the shuttle hook 4. FIG. 5 is an enlarged view of section V in FIG. 4. FIG. 6 is an enlarged cross-sectional view showing the rail 30 of the shuttle hook 5 fitted into the track groove 25 of the shuttle hook 4. FIG. 7 is an enlarged view of section VIII in FIG. 6. FIG. 8A is a front view showing the vertical full-rotating hook 1 in a first rotation position. FIG. 8B is a front view showing the vertical full-rotating hook 1 in a second rotation position. FIG. 8C is a front view showing the vertical full-rotating hook 1 in a third rotation position. Note that for ease of illustration, FIG. 8A omits a portion of the shuttle hook flange 27 and the point member.

[0032] The vertical full rotary hook 1 of this embodiment includes an outer hook 4 fixed to one end of a lower shaft 3 that is driven to rotate about a rotation axis L2 perpendicular to the movement path L1 of a sewing needle 2 that reciprocates up and down, an inner hook 5 housed in the outer hook 4, a bobbin case 6 detachably attached to the inner hook 5, and a bobbin housed in the bobbin case 6 and around which a bobbin thread is wound. The sewing needle 2 and lower shaft 3 described above are provided in a lockstitch sewing machine.

[0033] The rotary hook 4 and the rotary hook 5 are made of, for example, steel or stainless steel. The lower shaft 3 is made of a metal such as a structural steel bar, is supported by bearings 7 so as to be rotatable about the rotation axis L2, and is inserted into a metal sleeve 10. The bottom 21 of the rotary hook 4 is detachably fixed to the lower shaft 3 by bolts 38.

[0034] The sleeve 10 is housed in the sewing machine bed of the lockstitch sewing machine and is fixed to the sewing machine bed by another mounting member such as a bracket. Rotational force from an electric motor is transmitted to the other end of the lower shaft 3 via a rotational force transmission device such as a reducer, and the lower shaft 3 and the outer shuttle 4 are rotated around the rotation axis L2 at a high speed of, for example, about 8,000 rpm to 12,000 rpm.

[0035] A short cylindrical fitting recess 33 is provided at one end of the sleeve 10, and a bearing 7 is fitted into the fitting recess 33. The bearing 7 has an outer ring 11 fitted into the sleeve 10, an inner ring 12 through which the lower shaft 3 is inserted and fixed to the lower shaft 3, and a plurality of spherical rolling elements 13 fitted between the outer ring 11 and the inner ring 12. The bearing 7 may be an angular contact ball bearing.

[0036] A pair of fitting grooves 34a, 34b are formed in the inner periphery of one end of the sleeve 10 adjacent to the bearing 7. Annular seal members 35a, 35b (collectively referred to as "seal members 35") are fitted into the pair of fitting grooves 34a, 34b. The seal members 35a, 35b are spaced apart in a direction parallel to the rotation axis L2. The inner periphery of each seal member 35a, 35b resiliently contacts the outer periphery of the lower shaft 3, and a cylindrical space 16 is airtightly defined between the inner periphery of the sleeve 10 and the outer periphery of the lower shaft 3 between the seal members 35a, 35b. Each seal member 35a, 35b may be an O-ring made of synthetic rubber or synthetic resin, for example.

[0037] A radial hole 14 extending in a radial direction perpendicular to the rotation axis L2 of the lower shaft 3 is formed between the seal members 35a, 35b at one end of the lower shaft 3. A shaft hole 15 extending coaxially with the rotation axis L2 is formed at one end of the lower shaft 3. The radial hole 14 and the shaft hole 15 are in communication with each other. A connecting hole 17 is formed at one end of the sleeve 10. The connecting hole 17 opens to face the space 16.

[0038] The radial hole 14 communicates with the space 16 and the axial hole 15. Therefore, compressed air supplied to the connecting hole 17 from the compressed air pressure source 18 through the connecting pipe 19 flows into the radial hole 14 via the space 16 and is supplied to the air vent 24 of the outer rotary hook 4 through the axial hole 15. The pressure of the compressed air output from the compressed air pressure source 18 to the connecting pipe 19 is, for example, 5 kg / cm. 2 More than 10kg / cm 2 It may be the following:

[0039] The connecting hole 17 extends radially between the inner and outer circumferential surfaces of the sleeve 10. A flexible connecting pipe 19 is airtightly connected to the connecting hole 17. The compressed air source 18 can be an existing device such as a compressor that is installed in sewing factories and used to blow away and remove foreign matter such as lint adhering to the sewing machine bed or the material being sewn. The connecting hole 17 may be configured to detachably connect the connecting pipe 19, for example, by a quick disconnect coupling.

[0040] <Outer hook> The rotary hook 4 includes a cylindrical rotary hook body 20, a bottom 21 connected to one axial end of the rotary hook body 20 that is aligned with the rotation axis L2 and fixed to one end of the lower shaft 3, a rotary hook presser member 22 having a point 8 that captures the needle thread inserted into the sewing needle 2, a spring member 23 having an L-shaped cross section that is fixed to one axial end of the rotary hook body 20, and a peripheral wall portion 43 having a track groove 25.

[0041] The rotary hook retainer member 22 is detachably fixed to the rotary hook main body 20 by a bolt 52. The spring member 23 is detachably fixed to the rotary hook main body 20 by a bolt 53.

[0042] 3 and 4, ventilation holes 24 are formed in the rotary hook body 20 and the bottom portion 21. The ventilation holes 24 include a first ventilation hole 24a provided on the side where the tip 8 is located with respect to an imaginary plane C1 that includes the rotation axis L2 and on which the tip of the tip 8 is in contact, and a plurality of (two in this embodiment) second ventilation holes 24b, 24c provided on the side opposite the side where the tip 8 is located with respect to the imaginary plane C1. The first ventilation hole 24a and the second ventilation holes 24b, 24c are collectively referred to as ventilation holes 24.

[0043] A raceway groove 25 is formed on the inner periphery of the peripheral wall portion 43 of the rotary hook body 20. The raceway groove 25 extends in the circumferential direction with the rotation axis L2 as its center.

[0044] A recessed groove 37 extending in the circumferential direction is provided at the bottom of the raceway groove 25 of the outer rotary hook 4. As shown in Fig. 5, the cross section of the recessed groove 37 is semicircular, and communicates with the first air hole 24a and the second air holes 24b and 24c.

[0045] The portion of the inner circumferential surface of each of the air vents 24a to 24c that is located most radially outward with respect to the rotation axis L2 and the portion of the recessed groove 37 that is located most radially outward with respect to the rotation axis L2 are connected at a common point m. Therefore, no stepped surface that rises in a direction intersecting the air flow exists between each of the air vents 24a to 24c and the recessed groove 37, and no significant flow resistance is generated in the air flow that flows from each of the air vents 24a to 24c into the raceway groove 25. This allows the air flow rate from each of the air vents 24a to 24c into the raceway groove 25 to flow in without a significant decrease.

[0046] Fig. 6 is an enlarged cross-sectional view showing the state in which the rail 30 of the inner hook 5 is fitted into the track groove 25 of the outer hook 4, and Fig. 7 is an enlarged view of section VII in Fig. 6. The outer peripheral surface 30a of the rail 30 and the inner peripheral surface 25a of the track groove 25 are separated from each other by a gap ΔL of 0.04 mm or more and 0.08 mm or less in a direction perpendicular to the rotation axis L2.

[0047] With this configuration, an air layer is reliably formed between the rail 30 and the rail groove 25 over the entire circumferential direction by the air flowing in from each of the air vents 24a to 24c, preventing the rail 30 and the rail groove 25 from coming into contact with each other with excessively large contact pressure. Therefore, even when the outer hook 4 is rotated at high speed, seizure between the rail 30 and the rail groove 25 can be prevented. Therefore, since seizure between the rail 30 and the rail groove 25 can be prevented without using lubricating oil, it is possible to provide a vertical full-rotating hook 1 that does not stain the upper thread, bobbin thread, the sewing material, etc., with lubricating oil.

[0048] <Inner hook> 8A to 8C, the rotary hook 5 includes a substantially cylindrical rotary hook body 26, a rotary hook flange 27 connected to one axial end of the rotary hook body 26 that is aligned in a straight line with the rotation axis L2 and protruding radially outward, a rail 30 provided on the outer periphery of the rotary hook body 26 and extending circumferentially from the yarn separating portion 28 to the yarn release portion 29, a bottom portion 31 connected to one axial end of the rotary hook body 26 and extending in one diameter direction, and a stud 32 erected on the bottom portion 31 and extending toward the one axial end of the rotary hook body 26.

[0049] One longitudinal end of a latch member provided on the bobbin case 6 is detachably engaged with the stud 32. When the bobbin thread wound on the bobbin is consumed, the bobbin case 6 is removed from the rotary hook 5 when the bobbin with the consumed bobbin thread is replaced with a new bobbin with the consumed bobbin thread wound thereon, and is then reattached to the rotary hook 5 after the bobbin has been replaced. The track groove 25 may be made of, for example, metal. The rail 30 may be made of, for example, synthetic resin, preferably heat-resistant synthetic resin.

[0050] <Ventilation holes> The first air hole 24a is provided on the side where the tip 8 is located with respect to the imaginary plane C1, and more specifically, it is provided on the end face 22a of the hook retainer member 22 on the downstream side in the hook rotation direction D, and at an angular position that forms a first angle θ1 downstream in the hook rotation direction D from the imaginary plane C1 that includes the rotation axis L2 and with which the tip of the tip 8 contacts.

[0051] The first angle θ1 is selected, for example, to be equal to or greater than 40° and equal to or less than 90°. The inner diameter d of the first vent hole 24a and the second vent holes 24b, 24c may be, for example, 1.3 mm. The inner diameters of the first vent hole 24a and the second vent holes 24b, 24c may be the same or different values ​​as long as the required pressure and flow rate are ensured within the track groove 25.

[0052] By selecting the first angle θ1 in FIGS. 8A to 8C to be equal to or greater than 40° and equal to or less than 90°, the mechanical strength of the bottom portion 21 of the outer hook 4 can be maintained within an allowable range, and the first air holes 24a can be provided in the bottom portion 21.

[0053] The two second air vents 24b, 24c are provided on the opposite side of the imaginary plane C1 from the side on which the point 8 is located. More specifically, one second air vent 24b is provided at an angular position that forms a second angle θ2 upstream from the angular position of the first air vent 24a in the hook rotation direction D, and the other second air vent 24c is provided at an angular position that forms a third angle θ3 upstream from the angular position of the one second air vent 24b in the hook rotation direction D. The second angle θ2 is selected, for example, from 90° to 180°. The third angle θ3 is selected, for example, from 10° to 90°.

[0054] By selecting the second angle θ2 to be equal to or greater than 90° and equal to or less than 180°, the mechanical strength of the bottom portion 21 of the rotary hook 4 can be maintained within an acceptable range, and one of the second air vent holes 24b can be provided in the bottom portion 21. Furthermore, by selecting the third angle θ3 to be equal to or greater than 10° and equal to or less than 90°, the mechanical strength of the bottom portion 21 of the rotary hook 4 can be maintained within an acceptable range, and the other of the second air vent holes 24c can be provided in the bottom portion 21.

[0055] The first air vent 24a and the second air vents 24b, 24c respectively communicate with an inlet 44 and first and second outlets 45a, 45b provided in the bottom 21 of the outer rotary hook 4. The inlet 44 is formed as a flat, truncated cone-shaped space with its central axis coincident with the rotation axis L2 of the bottom 21. The first outlet 45a is an opening that communicates with the space of the raceway groove 25 via the first air vent 24a, and the second outlet 45b is an opening that communicates with the space of the raceway groove 25 via the second air vents 24b, 24c. Therefore, compressed air supplied to the inlet 44 is supplied to the space of the raceway groove 25 via the first air vent 24a and the second air vents 24b, 24c.

[0056] As shown in Figure 8A, the thread release portion 29 is disposed at an angular position of a fourth angle θ4 upstream from the imaginary plane C1 in the direction of rotation D of the outer hook. The thread dividing portion 28 is disposed at an angular position of a fifth angle θ5 downstream from the imaginary plane C1 in the direction of rotation D of the outer hook. The upper thread captured by the blade point 8 forms an upper thread loop while being hooked on the thread dividing portion 28, and then the thread is released from the thread release portion 29, completing one stitch.

[0057] In this embodiment, a plurality of (three in this embodiment) second air holes 24b, 24c are formed on the opposite side of the first air hole 24a with respect to the imaginary plane C1. Therefore, when the upper thread passes between the abutment portion of the thread release portion 29 facing downstream in the hook rotation direction D and the protrusion of the hook rotation prevention member during thread threading, the upper thread presses the hook 5 upstream in the hook rotation direction D. Even if this presses the hook 5 toward the opposite side of the imaginary plane C1 from the side where the blade tip 8 is located (the left side in Figure 3), compressed air is released from the second air holes 24b, 24c, causing an airflow to pass between the outer surface 30a of the rail 30 and the recovery surface of the rail hole 25, thereby preventing the rail 30 and the inner peripheral portion of the rail groove 25 from coming into contact with each other with great force.

[0058] According to this embodiment, the rotary hook 4 is provided with an air vent 24 that opens toward the track groove 25, and compressed air is supplied to the air vent 24. The rail 30 of the rotary hook 5 fits into the track groove 25 of the rotary hook 4, and compressed air is supplied between the rail 30 and the track groove 25 through the air vent 24.

[0059] When the rotary hook 4 is rotated about the rotation axis L2, compressed air passes between the track groove 25 and the rail 30. This compressed air reduces the frictional resistance caused by contact between the track groove 25 of the rotary hook 4 and the rail 30 of the rotary hook 5, thereby reducing the rotational resistance of the rotary hook 4. This prevents seizure between the rail 30 and the track groove 25, even when the rotary hook 4 is rotated at high speed, allowing for smooth thread passing and the formation of high-quality seams. Therefore, unlike the prior art, it is not necessary to form the rail 30 of the rotary hook 5 from a heat-resistant synthetic resin, and it is also not necessary to form a coating on the rail 30. This reduces the manufacturing cost and shortens the manufacturing time of the vertical rotary hook 1. Furthermore, since no lubricating oil is required, the upper thread, lower thread, and the sewing material are not contaminated by the lubricating oil, improving the efficiency of the sewing operation.

[0060] <Notch> Fig. 9 is an enlarged front view of the vicinity of the notch 54, and Fig. 10 is an enlarged perspective view of the vicinity of the notch 54. The rail 30 has the notch 54 that opens radially outward. The notch 54 has a first surface 55 that extends radially outward and a second surface 56 that faces the first surface 55. The notch 54 is provided at an angular position that forms an angle of 15° to 60° with respect to an imaginary plane C1 on the downstream side in the hook rotation direction D.

[0061] The first surface 55 extends radially outward of the rotary hook 5, and the second surface 56 inclines radially outward in a direction away from the first surface 55. The second surface 56 forms an angle α with a tangent to the outer peripheral surface of the rotary hook body 26. This angle α may be equal to or greater than 45° and equal to or less than 60°.

[0062] As described above, the rail 30 has a notch 54 that opens radially outward of the rail 30, and the compressed air passes through the notch 54. At this time, the compressed air collides with the first surface 55 and then flows out radially outward. This allows the flow of compressed air to act in the direction opposite to the direction D of rotation of the rotary hook 5. Therefore, the rotation of the rotary hook 5 accompanying the rotation of the rotary hook 4 can be suppressed, and the upper thread loop of the upper thread captured by the point 8 of the rotary hook 4 can smoothly pass through the rotary hook stopper portion where the rotary hook 4 and the rotary hook 5 abut.

[0063] This prevents seizure between the rail 30 and the track groove 25, even when the rotary hook 4 is driven to rotate at high speed, and allows the thread to pass smoothly, resulting in the formation of high-quality seams. Furthermore, since there is no need to use lubricating oil as in the prior art, the upper thread, lower thread, and the sewing material will not be soiled by the lubricating oil, and the efficiency of the sewing work can be improved.

[0064] Fig. 11 is an enlarged plan view showing a modified cutout portion 54a, and Fig. 12 is an enlarged perspective view of the cutout portion 54a shown in Fig. 11. The cutout portion 54a of this embodiment has a first surface 55a that extends at an inclination radially outward and a second surface 56a that faces the first surface 55a. The first surface 55a and the second surface 56a are parallel to each other in the deployed state and form an angle β. This angle β may be 45° or greater and 60° or less.

[0065] By adopting such a configuration, the cutout portion 54a has a first surface 55a and a second surface 55b, and therefore the compressed air flow passing through the cutout portion 54a comes into contact with the first surface 55a and the second surface 56a, which makes it possible to suppress co-rotation of the inner hook 5 with the rotation of the outer hook 4, thereby facilitating and smoothing the thread passing operation and improving the stitching quality.

[0066] Fig. 13 is a front view of a hook 4A according to another embodiment of the present invention. To avoid duplication, parts corresponding to those in the previous embodiment are designated by the same reference numerals. In this embodiment, as shown in Fig. 13, in addition to the first air vent 24a and the second air vents 24b and 24c, another second air vent 24d is formed.

[0067] Even when using such an outer hook 4A, the aforementioned inner hook 5 can be attached and compressed air can be passed through the cutout 54. With this configuration, it is possible to provide one more air hole 24 than in the above-mentioned embodiment. This allows compressed air to be supplied to the track groove 25 at a higher flow rate, thereby more reliably reducing contact of the rail 30 with the inner peripheral surface of the track groove 25.

[0068] <Horizontal full rotation hook> FIG. 14 is a perspective view of a horizontal full-rotating hook 51 according to yet another embodiment of the present invention. FIG. 15 is an exploded perspective view of the horizontal full-rotating hook 51. FIG. 16 is a plan view of the outer hook 4B. FIG. 17 is a front view of the horizontal full-rotating hook 51 with a portion cut away. The same reference numerals are used for parts corresponding to those of the above-described embodiment. The horizontal full-rotating hook 51, which is the full-rotating hook of this embodiment, includes an inner hook 5 having a circumferentially extending track 30 on its outer periphery, and an outer hook 4B having a track groove 25 on its inner periphery into which the track 30 fits, and a blade point 8 that captures the needle thread supplied by the sewing needle 2. The outer hook 4B is driven to rotate about a rotation axis L2 while the inner hook 5 is prevented from rotating. The track 30 has a notch 54 that opens radially outward.

[0069] The rotary hook 4B has a rotary hook body 20 and a bottom 21, and air vents 24 are formed in the rotary hook body 20 and the bottom 21. The air vents 24 include a first air vent 24a provided on the side where the tip 8 is located with respect to an imaginary plane C1 that includes the rotation axis L2 and on which the tip of the point 8 contacts, and a plurality of (two in this embodiment) second air vents 24b, 24c provided on the side opposite the side where the tip 8 is located with respect to the imaginary plane C1. The first air vent 24a and the second air vents 24b, 24c are collectively referred to as air vents 24. A raceway groove 25 is formed in the inner peripheral portion of the peripheral wall 43 of the rotary hook body 20. The raceway groove 25 extends circumferentially about the rotation axis L2.

[0070] The rotary hook 5 includes a cylindrical rotary hook body 26, a rail 30 provided on the outer periphery of the rotary hook body 26 and extending in the circumferential direction, a bottom 31 connected to one axial end of the rotary hook body 26 and extending in one diameter direction, and a stud 32 erected on the bottom 31 and extending toward the one axial end of the rotary hook body 26.

[0071] The first air vent 24a is provided on the side of the imaginary plane C1 where the tip 8 is located, and is provided at an angular position that forms a first angle θ41 upstream in the hook rotation direction D from the imaginary plane C1 that includes the rotation axis L2 and is in contact with the tip of the tip 8. The first angle θ41 is selected, for example, from 50° to 115°. The second air vent 24b is provided at an angular position that forms a second angle θ42 upstream in the hook rotation direction D from the first air vent 24a. The second angle θ42 is selected, for example, from 115° to 250°. The other second air vent 24c is provided at an angular position that forms a third angle θ43 upstream in the hook rotation direction D from the second air vent 24b. The third angle θ43 is selected, for example, from 17° to 90°.

[0072] The inner diameter d of the first vent hole 24a and the second vent holes 24b, 24c may be, for example, 1.3 mm. That is, the inner diameter d is selected to be approximately 56% of the thickness T of the bottom portion 31. The inner diameters d of the first vent hole 24a and the second vent holes 24b, 24c may be the same or different values ​​as long as the required pressure and flow rate can be ensured within the raceway groove 25.

[0073] The outer hook 4B is provided with an air hole 24 that is supplied with compressed air and opens toward the track groove 25. The air hole 24 may be configured to include a first air hole 24a and three second air holes 24b, 24c, and 24d, similar to the embodiment shown in FIG.

[0074] According to the embodiment shown in Figures 14 to 17, the full rotary hook is configured as a horizontal full rotary hook 51. Therefore, even when the outer hook 4B is rotated at high speed, the cooling effect of the compressed air flowing between the rail 30 and the rail groove 25 suppresses the temperature rise of the rail 30 and the rail groove 25, making it possible to stably form high-quality seams at high speed and improve the production efficiency of the sewn material.

[0075] In still another embodiment of the present invention, the above-described notches 54, 54a may be replaced by a notch 54b having a first surface 55b and a second surface 56b, as shown in Fig. 18. The first surface 55b faces downstream in the hook rotation direction D and is formed in a V-shape in a plan view.

[0076] By adopting this configuration, as shown by arrows a and b, air that flows into the space within the cutout portion 54b from between the rail 30 and the rail groove 25 through each air vent 24 collides with the V-shaped first surface 55b, thereby adding flow resistance. This increases the pressure of the air passing through the space between the rail 30 and the rail groove 25, more effectively preventing the rail 30 from coming into contact with the inner surface of the rail groove 25 when the outer hook rotates.

[0077] In still another embodiment of the present invention, the aforementioned notches 54, 54a, 54b may be replaced by a notch 54c having a first surface 55c and a second surface 56c, as shown in Fig. 19. The first surface 55c is formed so as to be inclined in a direction approaching the second surface 56c as it moves downstream in the hook rotation direction D in a plan view.

[0078] By adopting this configuration, as shown by arrows c and d, air that flows into the space within the cutout portion 54c collides with the first surface 55c, which is inclined toward the second surface 56c as it moves downstream in the hook rotation direction D in a plan view, thereby adding flow resistance. This makes it possible to increase the pressure of the air passing through the space between the rail 30 and the rail groove 25, more effectively preventing the rail 30 from contacting the inner surface of the rail groove 25 during hook rotation.

[0079] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and various modifications and improvements are possible within the scope of the gist of the present invention. It goes without saying that all or part of the components constituting each of the above-described embodiments can be combined as appropriate within the scope of not contradicting each other. [Explanation of symbols]

[0080] 1 Vertical full rotation hook 2 sewing needle 3 Lower axis 4, 4A, 4B Outer hook 5 Inner hook 6 bobbin case 7. Bearings 8 Tip of the Sword 10 sleeves 11 Outer ring 12 Inner Circle 13 Rolling elements 14 diameter holes 15 Shaft hole 16 Space 17 Connection hole 18 Compressed air pressure source 19 Connecting pipe 20 Rotary hook body 21 Bottom 22 Inner hook retainer member 23 Spring member 24 ventilation holes 24a First ventilation hole 24b, 24c, 24d Second ventilation hole 25 Track groove 26 Inner hook body 27 Inner flange 28 Thread separation section 29 Thread removal section 30 Rail 31 Bottom 32 studs 33 Fitting recess 34a,34b Fitting groove 35; 35a, 35b sealing member 37 Groove 38 volts 39 Inner hook retainer member 43 Peripheral wall part 44 Inlet 45a 1st outlet 46b 2nd outlet 51 Horizontal full rotation hook 52 volts 53 volts 54,54a,54b,54c Notch C1 Virtual plane D Rotation direction of outer hook L1 movement path L2 rotation axis

Claims

1. an inner hook having a rail extending in a circumferential direction on an outer periphery thereof; The sewing machine includes an outer hook having a track groove on its inner periphery that defines a space into which the track fits, and a point that captures the needle thread supplied by the sewing needle, wherein the outer hook is a fully rotating hook that is driven to rotate about a rotation axis while the inner hook is prevented from rotating, the outer casing includes a bottom portion having an inlet through which compressed air is supplied, and a peripheral wall portion having a plurality of outlets that open toward the space of the raceway groove, The bottom portion and the peripheral wall portion are provided with vent holes that communicate with the inlet and the outlet, A full-rotation hook characterized in that the rail has a notch that opens radially outward.

2. 2. The rotary hook according to claim 1, wherein the notch portion has a first surface extending radially outward and a second surface opposing the first surface.

3. 3. The rotary hook according to claim 2, wherein the first surface is positioned facing downstream in the rotation direction of the outer hook.

4. 3. The rotary hook according to claim 2, wherein the first surface is bent so as to be convex toward the upstream side in the rotation direction of the outer rotary hook.

5. 3. The rotary hook according to claim 2, wherein the first surface and the second surface are spaced apart in the circumferential direction.

6. 3. The rotary hook of claim 2, wherein said second surface extends radially outward.

7. the plurality of outlets include a first outlet and a second outlet, 7. The rotary hook according to claim 1, wherein the air vents include: a first air vent that communicates with the inlet and the first outlet, the first air vent being provided on the side on which the tip is located with respect to an imaginary plane that includes the rotation axis and on which the tip of the tip is in contact; and a second air vent that communicates with the inlet and the second outlet, and being provided on the side opposite the side on which the tip is located with respect to the imaginary plane.

8. 7. The rotary hook according to claim 1, wherein a recessed groove extending in a circumferential direction is provided on a bottom surface of the raceway groove.

9. 7. The full-rotation hook according to claim 1, which is a vertical full-rotation hook.

10. 7. The full-rotation hook according to claim 1, which is a horizontal full-rotation hook.

11. The full rotation hook according to any one of claims 1 to 6, characterized in that the outer peripheral surface of the rail and the inner peripheral surface of the rail groove are separated by a gap of 0.04 mm or more and 0.08 mm or less in a direction perpendicular to the rotation axis.

12. 7. The full-rotation hook according to claim 1, wherein the rail is made of a heat-resistant synthetic resin.

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