JPH0249759B2 - - Google Patents

Description

[Detailed description of the invention] Industrial applications The present invention relates to a full rotary hook and sewing machine.

Conventional technology Conventionally, full-rotation hooks installed in lockstitch sewing machines, etc., have a track formed on the outer circumferential surface of the inner hook, a track groove formed on the inner circumferential surface of the outer hook, and the rail fits into the track groove. In the closed state, the outer hook is driven to rotate around its rotation axis. In synchronization with the rotational movement of the outer hook, the needle thread slides on the bottom of the inner hook and passes through the inner hook, thereby performing a sewing operation. In such a full-rotation hook, when the outer hook is driven to rotate at high speed, the upper thread moves faster, and the sliding friction between the inner hook and the upper thread loop increases, causing the thread near the lower end of the bottom of the inner hook to This can cause looping or thread breakage.

In order to solve this problem, conventionally, as shown in FIG. An inclined surface 4 is formed which extends over a range of 160 degrees or less. The inclined surface 4 is formed so as to taper from the rail 6 of the inner hook 2 toward the bottom 7 toward the bottom 7.

However, in such prior art, the position where the inclined surface 4 is formed is located at the upper thread 5 shown in FIG.
Since the position is shifted from the vicinity of the lower end 7a of the bottom portion 7 of the inner hook 2 where the needle thread loop gets caught, there was a problem in that it was not possible to reliably prevent the needle thread loop from getting caught.

Problems to be Solved by the Invention An object of the present invention is to provide a full-rotation hook that allows the upper thread to smoothly pass through the bottom surface of the inner hook even when the outer hook rotates at high speed. .

Means for Solving the Problems The present invention provides an arrangement in which the bottom portion 22 of the inner hook 20 is located approximately 95 degrees downstream in the outer hook rotating direction A from a plane including the needle drop position P1 and the axis l1 of the inner hook 20. , within a range of 10 degrees to the upstream side of the outer hook rotation direction A, 210 degrees to the downstream side of the outer hook rotation direction A, and the axis l
An inclined surface 31 is formed on the open end side of the inner pot 20 with an angle θ3 in the range of 1 degree or more and 45 degrees or less as it moves outward in the radial direction with respect to the virtual plane S perpendicular to the imaginary plane S. There is a full rotation hook.

Function According to the present invention, since the inclined surface is formed on the bottom surface of the inner hook, the needle thread that passes through the thread while contacting the bottom surface of the inner hook during sewing is guided along the inclined surface, and the needle thread is threaded smoothly. It becomes possible to perform a crossing motion.

Embodiment FIG. 1 is a perspective view of an inner pot 20 according to an embodiment of the present invention, and FIG. 2 is a longitudinal sectional view thereof. The inner hook 20 provided in the vertical full-rotation hook includes a peripheral wall 21 formed in a roughly right cylindrical shape, a bottom portion 22 formed on one side in the axial direction of the peripheral wall 21, and a flange 23 formed on the other side of the peripheral wall 21. and has. Peripheral wall 21
A rail 24 is formed on the outer peripheral surface of the outer rotor, and when the inner rotor 20 is housed in the outer rotor, the rail 24 fits into the groove formed on the inner peripheral surface of the outer rotor, and the inner rotor 20 is supported. An inner hook rotation prevention recess 25 is formed in the flange 23 to prevent rotation of the inner hook 20 when the outer hook rotates, and the convex portion of an inner hook rotation prevention member (not shown) fixed to the base of the sewing machine is formed in the flange 23. becomes stuck and prevents rotation of the inner hook 20. Also, a needle 26 is provided on the open end side of the inner hook 20.
A needle drop hole 27 is formed through which the needle drop hole 27 is inserted. This needle drop hole 27 is provided at the needle drop position P1 of the needle 26, and the needle 26 that reciprocates up and down can freely pass therethrough.

A flat inclined surface 31 is formed on the bottom surface 30 of such an inner pot 20 over a range of an angle θ1 from the inner pot bottom surface 30. An angle θ1 extending in the circumferential direction of the inclined surface 31 is defined by 95 degrees downstream in the outer hook rotation direction A from a plane including the needle drop position P1 and the axis l1 of the inner hook 20, and upstream in the outer hook rotation direction A. 10 degrees to the side, 210 degrees to the downstream side of outer hook rotation direction A
It is set within a range of degrees. Moreover, this inclined surface 31 is
As it goes outward in the radial direction, the open end of the inner hook is inclined by an angle θ3 with respect to a virtual plane S perpendicular to the axis l1. This angle θ3 is, for example, 1 to 45 degrees. When this angle θ3 is less than 45 degrees, the inclined surface 3
1 has almost no function of guiding the needle thread. Moreover, if the angle θ3 is larger than 45 degrees, the movement of the needle thread moving from the bottom to the top in FIG. 2 along the bottom surface 32 of the inner hook will be blocked by the inclined surface 31. In order to avoid such problems, the angle θ3 is selected to be greater than or equal to 1 degree and less than or equal to 45 degrees, and the angle θ3 is selected to be greater than or equal to 1 degree and less than or equal to 45 degrees. The thread passing operation of the upper thread can be smoothly guided. Furthermore, by providing the inclined surface 31 on the bottom 22 of the inner hook 20, when the upper thread slides on the bottom surface 30 of the bottom 22 of the inner hook 20, it is pulled near the lower end 22a of the bottom 22. It is possible to prevent the upper thread from getting caught, and thereby the upper thread can be smoothly guided along the inclined surface 31 and easily threaded.

FIG. 3 is a diagram for explaining the operation of threading the upper thread 33 along the outer peripheral surface of the inner hook 20.
The sewing operation is started, the needle thread 33 is captured by the tip, and a needle thread loop is formed as the outer hook rotates, as shown in FIG. 3. Furthermore, when the outer hook is further rotated, the upper thread 33 reaches the vicinity of the lower end 22a of the bottom portion 22 of the inner hook 20, as shown in FIG.
Further, as shown in FIG. 3, the upper thread 33 passes through the lower end 22a of the inner hook 20 and smoothly passes through the lower end 22a of the inner hook 20 without being caught on the lower end 22a of the bottom 22, as shown in FIG. It becomes possible to easily pass through the thread. By forming the inclined surface 31 on the bottom portion 22 of the inner hook 20 in this way, the outer hook 24 can be rotated at high speed around its axis, thereby improving the sewing speed. It becomes possible.

Figure 4 shows the axis l1 below the inner hook axis l1.
FIG. 2 is a cross-sectional view taken from above using a horizontal plane parallel to the cut plane. In the above embodiment, the inclined surface was flat, but in another embodiment of the present invention, the inner pot 2
Alternatively, a truncated conical inclined surface 31a may be formed at the bottom. Such a truncated conical inclined surface 31a
also includes the angle θ1 in the range in which the inclined surface 31 of the above-mentioned embodiment is formed, and can be formed over the entire circumference in one polishing operation, making the processing operation easy.

As another embodiment of the present invention, the inclined surfaces 31, 31
a may be curved so as to be outwardly convex to the left side in FIGS. 2 and 4.

Furthermore, as another embodiment of the present invention, although the above-mentioned embodiments have been described with respect to a vertical full-rotation hook, the present invention can also be suitably implemented in a horizontal full-rotation hook.

Effects of the Invention According to the present invention, since an inclined surface is formed on the outer circumferential surface of the bottom surface of the inner hook, when the upper thread slides along the bottom surface of the inner hook during sewing, this inclined surface The thread is guided smoothly and can be easily passed through without getting caught at the bottom of the inner hook. This makes it possible to rotate the outer hook at a high speed, thereby increasing the sewing speed.

Further, according to the present invention, the inclined surface 31 is located on the upstream side in the outer hook rotation direction A with respect to the downstream side in the outer hook rotation direction A from a plane including the needle drop position P1 and the axis of the inner hook 20. The lower end of the bottom of the inner hook 20, where the needle thread loop is most likely to get caught, is on the side that avoids the thread path of the needle thread loop. This eliminates the need to unnecessarily increase the diameter of the upper thread loop, and allows the thread to be easily passed through.

Moreover, the inclined surface 31 has an angle θ3 of 1 degree or more and 45 degrees or less, which is inclined toward the open end of the inner rotor 20 with respect to the virtual plane S perpendicular to the axis of the inner rotor 20 as it moves outward in the radial direction. This also facilitates threading of the upper thread loop. That is, even if an inclined surface with the angle θ3 of less than 1 degree is formed, it is hardly possible to obtain the function of guiding the needle thread loop. Also, if the angle θ3 is selected to be larger than 45 degrees, the inclined surface 3
The angle of the corner on the base end side, that is, the corner on the bottom surface 32 side of the bottom portion 22, is larger than the corner on the open end side of the inner hook 1, and therefore the needle thread loop is guided by the inclined surface. Most of the functionality is gone. Such problems can be prevented by forming the inclined surface 31 of the present invention, and it is possible to smoothly and reliably pass the needle thread loop over the needle thread, thereby forming a high-quality seam.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of an inner hook 20 according to an embodiment of the present invention, FIG. 2 is a longitudinal sectional view thereof, FIG. 3 is a diagram for explaining the thread passing operation of the upper thread 33, and FIG. FIG. 5 is a sectional view of another embodiment of the invention, FIG. 5 is a sectional view of a typical prior art, and FIG. 6 is a diagram for explaining problems of the prior art. 20... Inner hook, 21... Peripheral wall, 22... Bottom, 24... Rail, 25... Inner hook detent recess, 26... Needle, 27... Needle drop hole, 30... Bottom surface, 31, 31a... Slanted surface.

Claims (1)

[Claims] 1. On the bottom part 22 of the inner hook 20, there is a 10 degree angle on the upstream side in the outer hook rotation direction A, with a reference point of approximately 95 degrees downstream in the outer hook rotation direction A from a plane including the needle drop position P1 and the axis l1 of the inner hook 20. degree, the angle θ3 is 1 degree or more toward the open end of the inner hook 20 within a range of 210 degrees downstream in the outer hook rotation direction A, and radially outward with respect to the virtual plane S perpendicular to the axis l1. , 45
A full-rotation hook characterized by forming an inclined surface 31 which is inclined within a range of less than 100 degrees.