JPH0658878U - Full rotary hook of sewing machine - Google Patents

Abstract

(57) [Summary] (Correction) [Purpose] An inner hook holding a bobbin case containing a bobbin wound with a lower thread on one side is rotatably fitted and held, and the other side has a connecting shaft and needle receiving member. In a zigzag sewing machine or a full rotary hook used for an embroidery sewing machine, thread breakage due to the upper thread wrapping around the back surface of the outer hook during sewing is prevented. [Structure] A U-shaped upper thread made of a wire material such as a steel wire that connects a tip end portion 26A of a thick wall portion 26 of a needle receiving member 3 and a terminal end of an outer peripheral surface 15 of an outer hook 1 on a sword tip 6 side. The guide piece 30 is provided, and the maximum axial height H1 of the needle thread guide piece 30 is the axial height of the terminal end 31 of the boundary line 16 between the inclined surface 14 and the outer peripheral surface 15 of the outer hook 1 on the sword tip 6 side. A full rotary hook of a sewing machine that is equal to or slightly larger than

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention mainly relates to a rotary hook used for zigzag and embroidery lockstitch sewing machines.

[0002]

[Prior art]

 As is well known, the crossing of the upper thread and the lower thread in the lockstitch sewing machine is performed by relative movement between the vertical movement of the needle and the rotary movement of the rotary hook. That is, the needle thread is moved up and down to form a loop near the lowermost end of the needle, and the rotary hook of the rotary hook inserts the tip of the rotary hook into this loop portion. Then, the rotary hook is further rotated, and by passing the loop portion of the upper thread through the front and back of the bobbin case and the inner hook held by the rotary hook, the bobbin wound on the bobbin is crossed. ing.

An example of a conventional full rotary hook related to the present invention will be described with reference to FIGS. 2 to 4. This full-rotary hook has a bobbin case (not shown) accommodating a bobbin (not shown) wound with a bobbin thread (not shown) and an outer pot 1 connected to a drive shaft (not shown). No. 2), a needle receiving member 3 fixed to the back side of the outer hook 1, and a crescent-shaped half-cut ring 4 for rotatably holding the inner hook 2 on the outer hook. The details will be described below. The outer pot 1 is shown in FIGS. 2 and 3. This outer hook 1 has a cutout portion formed on the outer peripheral surface thereof and a sword tip 6 extending to the cutout portion 5, and a connection shaft 7 connected to a drive shaft (not shown) is formed on the back surface thereof. The connecting shaft 7 has a flat portion 7a for circumferential positioning and fixing. Further, an inner hook 2 for holding a bobbin case (not shown) accommodating a bobbin (not shown) wound with a bobbin thread (not shown) is rotatably assembled on the front side of the outer hook 1. Has been. That is, an outer peripheral portion of the outer pot 1 is formed with an axially raised edge portion 8, and a sliding groove 9 is formed in the inner periphery of the edge portion in the circumferential direction. Then, a sliding band 10 formed on the outer peripheral portion of the inner hook 2 is fitted into the sliding groove 9, and the half-break ring 4 is screwed as shown in FIG. It is assembled in a state in which it is rotatable with respect to 1 and is restricted in the axial direction. The inner hook 2 has a substantially disk-like shape, and has a bobbin case mounting shaft 11 in the center thereof and a locking tongue which is engaged with an inner hook rotation stopper piece (not shown) attached to the sewing machine main body at the outer peripheral portion. An inner hook point 13 is formed on the sliding band 10.

The tip of the sword tip 6 extends in the direction of the notch 5 and is formed in a shape inclined in the direction of the connecting shaft 7. The tip 6 of the sword has an inclined surface 14 that increases in height as it moves from the tip to the root, and a conical surface having a boundary line 16 between it and the outer peripheral surface 15 of the outer hook. The inclined surface 14 has a recess 17 formed therein.

The needle receiving member 3 is shown in FIGS. 4 and 5. The needle receiving member 3 has a needle receiving body 18 to be located in the cutout portion 5 of the outer hook 1, a hole 19 for passing the connecting shaft 7 of the outer hook, and a positioning fixing for fixing to the outer hook 1. It has a protrusion 20 and the like. The needle receiving member 3 is joined to the back surface of the outer hook 1 only, and the positioning fixing projection 20 is fitted into the needle receiving member positioning hole 21 provided in the outer hook 1 for accurate positioning. In this state, the screw 23 passed through the hole 22 of the needle receiving member is screwed and fixed in the screw hole 24 provided in the outer pot 1. Further, the needle receiving member 3 is formed with a thick portion 26 at a portion corresponding to the position of a ridge line 25 formed between the root portion of the sword tip 6 of the outer hook and the back surface of the outer hook.

In the structure as described above, the inner hook 2 is made non-rotatable by the locking tongue piece 12, and the bobbin case (not shown) is rotated by the rotational movement of the outer hook 1 synchronized with the vertical movement of the needle (not shown). The upper thread 27 held by the needle (not shown) is crossed with the lower thread (not shown) drawn out from the upper part. That is, when the needle slightly moves up from the lowermost position, the needle thread 27 held by the needle becomes a slack loop. The tip of the sword tip 6 of the rotating outer hook 1 is inserted into this loop portion, and the upper thread 27 is divided into two directions. That is, one is caught by the inner hook blade point 13 of the inner hook 2 and wraps around the back surface 28 of the stationary inner hook 2 so as to wrap around, and the other wraps around the inclined surface 14 of the outer hook 1. FIG. 5 shows a locus of movement of the upper thread 27 wound around the inclined surface 14 of the outer hook 1 as the outer hook 1 rotates. As shown in FIG. 5, the needle thread 27 first moves along the upper surface of the thick portion 26 of the needle receiving member 3 as the outer hook 1 rotates, and then on the slope 29 facing the recess 17. After being guided, the locus A and the locus B are traced sequentially. Therefore, the upper yarn 27 passes above the bobbin case (not shown) as the outer hook 1 rotates. Therefore, the upper thread 27 intersects with the lower thread led out from the bobbin case, and a stitch is formed.

[0007]

[Problems to be solved by the device]

 The loci A and B of the upper thread shown in FIG. 5 are regular loci for forming stitches. Therefore, if the upper thread 27 follows this regular locus, the upper thread and the lower thread inevitably intersect to form a stitch. However, sometimes, as shown in FIG. 6, the upper thread 27 wraps around the back surface of the outer hook, that is, the connecting shaft 7 side. When such a phenomenon occurs, thread breakage always occurs, sewing work stops, and time loss occurs. The present invention is to solve this.

[0008]

[Means for Solving the Problems]

 The reason for this is that the upper thread 27 moves toward the outer peripheral surface 15 of the outer hook 1 due to excessive slack of the upper thread 27, etc., and therefore the regular movement loci A, B along the slope 29 of the inclined surface 14. It is thought that it cannot slip in the order of and goes around to the back. In the present invention, in order to solve this, as shown in FIGS. 1A and 1B, the outer peripheral end surface 26A of the thick portion 26 of the needle receiving member 3 and the end of the outer peripheral surface 15 of the outer hook 1 on the sword tip 6 side. As shown in FIG. 7, the upper thread guide piece 30 was formed into a U-shape with a wire material such as a steel wire and surface-treated so that the upper thread could easily flow. The maximum axial height H1 of the needle thread guide piece 30 is equal to or slightly greater than the axial height of the tip 31 of the boundary line 16 between the inclined surface 14 and the outer peripheral surface 15 of the outer hook 1.

[0009]

As shown in FIG. 1, the needle thread 27 first moves along the thick portion 26 of the needle receiving member 3 and then by the needle thread guide portion 32 of the present invention. It is ensured that the outer hook is guided in the direction of the inclined surface 14 of the outer pot, that is, as shown in FIG.

[0010]

【Example】

 An embodiment of the present invention will be described below with reference to FIGS. 1 (A), 1 (B) and 7. FIG. 7 is an enlarged perspective view showing an example of the needle thread guide piece 30. A steel wire isoelectric wire having a diameter of d = 1 mm as a whole is formed into a U-shape, and one end of the needle thread guiding portion 32 is perforated in the end face portion 26A of the thick portion 26 of the needle receiving member 3. It has a fixing portion 33 that is inserted and fixed in a small hole, and has a fitting portion 34 at the other end that fits into a small hole drilled near the tip of the outer peripheral surface 15 of the outer pot 1. The radius of curvature R1 of the needle thread guide portion 32 is the same as the radius of curvature of the outer peripheral portion 15 of the outer hook 1.

The needle thread guide piece 30 having the above structure is attached between the outer hook 1 and the needle receiving member 3 as shown in FIGS. 1 (A) and 1 (B). That is, the tip end portion 26A of the thick portion 26 of the needle receiving member 3 is cut off with a radius of curvature R2 centered on the axis of the connecting shaft 7 of the outer pot, and a small hole 37 is bored in this step portion 35, The fixing portion 33 of the thread guide piece 30 is inserted. On the other hand, in the outer hook 1, the vicinity of the sword tip side tip of the outer peripheral portion 15 is cut off with a radius of curvature R2 similarly to the needle receiving member, and a small hole 38 is bored in this step portion 36 to insert the needle thread guiding piece 30. 34 is inserted. Here, R2 is equal to or slightly smaller than the curvature obtained by subtracting the diameter d of the wire forming the needle thread guide piece 30 from R1.

Further, as shown in FIG. 1A, the height H1 of the highest point 39 with the needle thread guide piece 30 attached is between the inclined surface 14 and the outer peripheral surface 15 of the outer hook 1. The axial height of the tip end 31 (FIG. 2) of the boundary line 16 of FIG.

As a method of mounting the needle thread guide piece 30, the fixing portion 33 is attached to the needle receiving member by caulking after driving, and the fitting portion 34 is attached and detached to the outer hook here. The diameter of the small hole 38 is made slightly larger than the diameter d of the wire material constituting the needle thread guide piece 30. The fixing portion 33 may be attached to the needle receiving member by caulking, welding, brazing, bonding or the like.

[00014]

[Effect of device]

 According to the present invention, the upper thread is surely guided in the direction of the inclined surface 14 of the outer hook, and never goes around to the back surface of the outer hook. Therefore, there is no thread cutting for the upper thread to wrap around the back of the outer hook, and the time loss due to the stop of the sewing machine is eliminated.

[Brief description of drawings]

FIG. 1A is a side view of an assembly of a full rotary hook according to the present invention, which also shows the locus of the upper thread. (B) is a partially assembled front view of the full rotary hook according to the present invention.

FIG. 2 is an exploded perspective view of a conventional rotary hook.

FIG. 3 is a rear view of an outer hook of a conventional type.

FIG. 4 is a front view of a conventional needle receiving member.

FIG. 5 is a side view of the assembly of a conventional rotary hook in which the upper thread is traced.

FIG. 6 is a rear view of an assembly of a conventional full-rotary hook, showing a state in which an upper thread wraps around a back surface of the hook.

[Explanation of symbols]

 1 Outer hook 2 Inner hook 3 Needle receiving member 4 Half cut ring 5 Outer hook notch 6 Outer hook blade tip 7 Connecting shaft 13 Inner hook blade tip 14 Outer hook inclined surface 15 Outer hook outer peripheral surface 26 Needle receiving member thick part 27 Upper thread 29 Inclined surface 30 Upper thread guide piece 32 Upper thread guide part

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[Procedure amendment]

[Submission date] November 15, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Figure 7

[Correction method] Added

[Correction content]

FIG. 7 is a perspective view showing an example of a needle thread guide piece according to the present invention.

Claims (1)

[Scope of utility model registration request] 1. An inner hook (2) holding a bobbin case accommodating a bobbin wound with a lower thread on one surface is rotatably fitted and held, and a connecting shaft (7) and a needle receiving member (3) are on the other surface. In the full rotary hook having the above), the tip portion (26A) of the thick portion (26) of the needle receiving member (3) and the vicinity of the end of the outer peripheral surface (15) of the outer hook (1) on the sword tip (6) side are provided. An upper thread guide piece (30) made of a wire such as a steel wire to be connected is provided, and the upper thread guide piece (3) is provided.
The maximum axial height (H1) of (0) is the end (31) of the boundary line (16) between the inclined surface (14) and the outer peripheral surface (15) of the outer hook (1) on the sword tip (6) side. The full rotary hook of the sewing machine, which is equal to or slightly larger than the axial height of the sewing machine.