JPH0466599B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD The present invention relates to a hem sewing device for folding and sewing the hem of underwear, etc. in a sewing machine.

BACKGROUND OF THE INVENTION As shown in FIGS. 1 and 2, the hem of underwear is usually folded inward and sewn with an overlock seam. This is the so-called hemming stitch. As shown in Fig. 3, this hem stitching is performed by folding the right end of the work cloth C twice so that the first and second folds A and B are formed. Overlap the edge D on the first bent part A, and in this state, the right edge D
Then, overlock stitching is performed on the first folded part A, and after the sewing is completed, the first folded part A is returned to its original state as shown in FIG.

In order to efficiently carry out hem stitching as described above, a guide device as shown in FIG. 5 has conventionally been used. This guide device includes a guide stand 121 attached to the frame of the sewing machine, and a guide stand 121 attached to the frame of the sewing machine.
The guide table 121 is formed with a guide surface 121a that engages with the outer surface of the first folded part A of the work cloth C, and the ruler 122 has a second folded part A. Part B is accommodated. During sewing, the work cloth C is placed on the guide surface 1 as shown in FIG.
The stitch E is formed on the right edge D and the first bent portion A by being guided by the cloth feed direction line 21a and transferred toward the needle passing point.

However, as shown in FIGS. 1 and 6, for example, in the side-joining portion F, the two pieces of cloth are overlapped, so that the thickness increases and a stepped portion G is formed. This stepped portion G is the guide surface 121a.
When guided by
A concave portion H is formed. Therefore, if the work cloth C is transferred in this state and sewing is performed, the sewing will occur because there is no cloth in the recessed portion H. Then, the thread comes undone from this unstitched part, which significantly reduces the commercial value of the sewn product.

In order to solve this problem, a sewn-off prevention device described in Japanese Patent Publication No. 54-6944 was proposed. In this device, when the part of the recessed part H is sewn, the guide surface 121a moves to the right and the part of the recessed part H is sewn.
The work cloth C in the section is moved from the left side of the needle passing point to above the needle passing point. Therefore, in this device, although it is possible to prevent the concave portion H from coming off, there is a problem of overstitching. In other words, when the guide surface 121a moves to the right, the recessed portion H is located at the needle passing point, but the stepped portion G moves too far to the right from above the needle passing point and deviates from the needle passing point. Therefore, in the stepped portion G and its vicinity, the needle falls at a predetermined position, that is, at a position inwardly to the left of the position of the first folded portion A and the right edge D of the work cloth C. For this reason, when the work cloth C is brought into the state shown in FIG. 4 after sewing is completed, the seams are largely visible on the surface (the upper surface in FIG. 4) of the work cloth C, resulting in what is called an over-overlocked state.
Therefore, the appearance deteriorates, which lowers the commercial value of the sewn product in a different sense from the above.

OBJECTS OF THE INVENTION It is an object of the present invention to provide a hem sewing device for a sewing machine that solves the above-mentioned conventional problems and eliminates both loose stitching and over-overlocking.

Structure of the Invention In order to achieve the above object, in the present invention, a hemming ruler is movably supported on the cloth feed side of the work cloth feed means in a direction perpendicular to the cloth feeding direction by the work cloth feed means, and The hem ruler is placed at a distance from the workpiece cloth support surface with a cloth passing gap therebetween, and engages with the inner surface of the first folded part of the workpiece cloth to guide the workpiece cloth through the needle passage point. A cross section U is formed by a lower guide plate on which a guide surface extending along the feed direction line is formed, and an upper guide plate arranged with a gap capable of accommodating the second bent portion of the work cloth from the lower guide plate. a detection means for detecting the presence of a recess formed on the inner surface of the first folded portion of the work cloth; and a detection means for detecting the presence of a recess formed on the inner surface of the first folded portion of the work cloth, and the recess passing through the needle passing point based on detection by the detection means. and actuating means for moving the hemming ruler so that its guide surface moves away from the inner surface of the first bending portion.

Embodiment Hereinafter, an embodiment embodying the present invention will be described based on the drawings from FIG. 7 onwards. In Fig. 7, 1 is a sewing machine frame, 2 is a cloth plate, 3 is a throat plate,
4 is a feed dog; 5 is a needle bar having a sewing machine needle 6 at its lower end; 7 is a presser foot arm having a presser foot 8 pivoted at its lower end; 9
is a wire spring that biases the presser foot 8 in the direction of the presser foot. The workpiece cloth C on the cloth plate 2 and the throat plate 3 is moved along the cloth feed direction line toward the needle passing point of the sewing machine needle 6 by the cooperation of the presser foot 8 and the feed dog 4 that performs the known four-movement feed. is transported in one direction along the line.
Therefore, the upper surface of the cloth plate 2 and throat plate 3 constitutes a workpiece cloth support surface 10, and the feed dog 4
and the presser foot 8 constitute a workpiece cloth feeding means. Further, on the back surface of the presser foot 8, a groove portion 11 is formed along the cloth feeding direction line from the cloth feeding side to the needle passage point.

As shown in FIG. 8, a hemming guide device 21 is attached to the front right side of the sewing machine frame 1. Therefore, the configuration of this hem-pulling guide device 21 will be explained in detail below. A mounting base 23 is fixed to the front right side of the sewing machine frame 1 with screws 22. A device frame 25 is horizontally rotatably supported on the mounting base 23 by step screws 24. From there, it is rotated 90 degrees to the right to an unused position, as shown in the figure. Note that the mounting base 23 and the device frame 25 constitute a support body. Further, a stopper 26 is attached to the mounting base 23, and an elastic piece 27 is attached to the device frame 25, so that when the device frame 25 is placed in the use position, the device frame 25 is prevented from moving further by the stopper 26. Rotation in one direction of the sewing machine frame is restricted, and the hole 2 formed in the elastic piece 27
A protrusion 28 on the mounting base 23 is engaged with the protrusion 7a to elastically hold the device frame 25 in its use position.

On the upper surface of the device frame 25, a release lever 30 which is rotatably biased in one direction by a wire spring 31 is rotatably supported by a step screw 29 at an intermediate portion, and one arm portion 30a of the release lever 30 By operating the release lever 30 and rotating it clockwise in FIG. 8 against the spring force of the wire spring 31,
The other arm 30b of the release lever 30 is attached to the mounting base 23.
As a result, the device frame 25 is rotated to the non-use position side against the spring force of the elastic piece 27 due to the reaction force.

Left and right arms 25a, 25b of the device frame 25
The two holes 41 have support shafts 42 extending in the horizontal direction.
is inserted and supported so as to be movable in the axial direction. As shown in FIG. 10, a rotation prevention member 43 is fixed to an approximately intermediate portion of the support shaft 42, and a bifurcated portion 43a formed at the tip of the rotation prevention member 43 is attached to the device frame 25.
It is fitted into the upper fixing pin 44 and supports the support shaft 42.
rotation is blocked. As shown in FIGS. 8 and 11, a screw hole 45 is formed in the base end shaft center of the support shaft 42, and the screw hole 45 has an adjusting screw 46 having a knob 46a and a flange portion 46b. is screwed in. This flange portion 46b forms a regulating groove 4 formed in the device frame 25.
7, and this adjustment screw 46 is prevented from moving in the axial direction and is only allowed to rotate. Therefore, when the adjustment screw 46 is rotated,
By the action of the screw, the support shaft 42 is moved leftward or rightward along its axial direction.

Brackets 49 and 50 are fixed to the support shaft 42 between the arms 25a and 25b of the device frame 25 by screws 48, respectively. First and second rotary solenoids 51 and 52 are fixed to both brackets 49 and 50, respectively.
As shown in FIG. 2, rotating arms 53 and 54 are fixed to these output shafts, respectively. Also, the rotating arm 54 of the second rotary solenoid 52
12 by the spring 55 shown in FIGS.
It is biased clockwise in the figure.

A guide support 61 is fixed to the tip of the support shaft 42, and as shown in FIG. 13, a skirting auxiliary body 63 is rotatably supported in a horizontal plane by means of step screws 62 on its left end surface. The guide support 61
A detection shaft 68 is inserted into 65 and 66 which are provided through the hemming auxiliary body 63 so as to be slidable in the axial direction, and one end of the detection shaft 68 is inserted into the hemming auxiliary body 63.
A detection piece 70 located within a recess 69 formed on the left side surface 63a side is fixed. Further, a permanent magnet 71 is fixed to the other end of the detection shaft 68 on the right side of the guide support 61.
1 faces a reed switch 73 attached to the guide support 61 via a bracket 72, as shown in FIG. Further, as shown in FIG. 13, a recess 74 is formed in the hole 65 of the guide support 61.
is formed, a stopper 75 is fixed to the detection shaft 68 in the recess 74, and a stopper 75 is fixed to the detection shaft 68.
A coil spring 76 is inserted therein to bias the coil 8 toward the left. Then, the detection shaft 68 is moved to the left by the spring force of the coil spring 76, and the stopper 76 is moved to the left.
5 and the inner surface of the recess 74 are engaged, the left end surface of the detection piece 70 slightly protrudes outward from the left side surface 63a of the hemming auxiliary body 63. Further, when the detection shaft 68 is moved to the right against the spring force of the coil spring 6, the detection piece 70 moves to the inner side of the recess 74. When the permanent magnet 71 is moved left and right together with the detection shaft 68, the reed switch 73 outputs a predetermined electric signal. This permanent magnet 71 and reed switch 73 constitute a detection means.

Further, as shown in FIG. 13, the guide support 61
has an insertion hole 77 formed with a female thread at least at the right end thereof, and a hemming auxiliary body 63 is installed inside the insertion hole 77.
A pressing piece 78 facing the right side and the pressing piece 7
A spring 79 that applies a spring force to the hem 8 in the direction of the hemming auxiliary body 63, and a screw 80 that is screwed into the female thread to adjust the spring force of the spring 79 are inserted. Then, the hemming auxiliary body 63 is always rotated in one direction by the pressing action of the pressing piece 78 due to the spring force of the spring 79, and the stopper portion 63b at the cloth feeding side end of the hemming auxiliary body 63 and the guide support are rotated. 61, the hem-pulling auxiliary body 63 is held in the position shown in FIG. 13 by engagement with the left side surface. 67 This is a stopper that prevents the hem-pulling auxiliary body 63 from rotating in the other direction.

As shown in FIGS. 7 and 14, a guide recess 81 with guide walls 82 on both front and rear sides is formed on the upper surface of the guide support 61, and a ruler support 83 is movable left and right inside the guide recess 81. It is inserted. Regulation members 85 and 86 are fixed on both guide walls 82, respectively, and regulation members 85 and 86 are fixed at the right and left ends of the guide walls 82, respectively, and regulation members 85 and 86 are provided at their right and left ends opposite to the right and left end surfaces of walls 83a and 83b formed before and after the ruler support 83, respectively. Pieces 85a, 86
a is formed, and those regulating pieces 85a, 8
6a restricts the range of horizontal movement of the ruler support 83. Furthermore, lifting prevention pieces 85a and 85b are formed at the upper ends of both regulating members 85 and 86 to prevent the ruler support 83 from lifting up, in contact with the upper surfaces of the walls 83a and 83b of the ruler support 83, respectively. .

A ruler guide shaft 8 is provided between the two walls 83a and 83b.
7 is installed and fixed in parallel with the cloth feeding direction, and a movable body 88 is supported on the ruler guide shaft 87 so as to be movable back and forth. Further, a guide piece 83c is formed protruding from the left side surface of the ruler support 83.
A skirting ruler 90 is supported by a shaft 89 at the left end of the movable body 88 so as to be rotatable in a vertical plane. The hemming ruler 90 has a base 91
and a guide portion 92 fixed to the base portion 91 and formed to have a U-shaped cross section by an upper guide plate 93 and a lower guide plate 94. A guide tongue piece 94a extending forward is integrally formed on the right end of the lower guide plate 94, and a guide surface 94b formed on the right side of the guide tongue piece 94a is bent twice for hemming the work cloth C. The workpiece cloth C is guided by engaging with the inner surface of the first bent portion A of the workpiece cloth C. Further, a gap is formed between the upper guide plate 93 and the lower guide plate 94 to accommodate the second bent portion B of the work cloth C, and a screw 95a is loosened between the guide plates 93 and 94. A cloth receiver 95 whose left and right positions can be adjusted is arranged, and this cloth receiver 95 is arranged so that the workpiece cloth C
engages with the second bent portion B of and guides it.

As shown in FIG. 8, when this hemming ruler 90 is moved along the ruler guide shaft 87 together with the movable body 88 toward the cloth feeding side, the base 91 is moved against the upper surface of the guide piece 83c of the ruler support 83. The hem ruler 90 is held in a substantially horizontal state by engaging with the hem ruler 90, and in this state, the lower guide plate 94 is arranged with a cloth passage gap apart from the workpiece cloth support surface 10. At the same time, the guide tongue 94a of the lower guide plate 94 is located on the lower surface side of the presser foot 8 and enters the groove 11 of the presser foot 8, and the guide surface 94b of the guide tongue 94a is at the needle passing point. It extends along the cloth feeding direction line up to the vicinity. Further, when the hem ruler 90 is moved toward the cloth feed side along the ruler guide shaft 87 as shown by the two-dot chain line in FIG. Removed hem ruler 90
The upward rotation of is allowed, and in this way the hemming ruler 9
0 is rotated upward, the side surface of the guide piece 83c and the side surface of the base 91 face each other, and the hem ruler 90
is prevented from moving toward the cloth feeding side.

A bracket 96 is fixed to the support shaft 42 between the device frame 25 and the guide support 61 with screws 97.
6, an interlocking lever 99 is rotatably supported at the intermediate portion by a step screw 98, and the interlocking lever 99
A connecting link 100 is interposed between one arm 99a of the rotary solenoid 9 and the rotating arm 53 of the first rotary solenoid 51, and the other arm 99a
9b is fitted and connected to a long hole 88a formed in the movable body 88 by a shaft 101. When the first rotary solenoid 51 is energized, the rotating arm 53 is rotated clockwise in FIG. 12, and the interlocking lever 99 is thereby rotated counterclockwise as shown in FIG. The moving body 88 is moved to the cloth feeding side. A coil spring 102 is fitted onto the step screw 98 to bias the interlocking lever 99 clockwise.

Also, one wall 83b of the ruler support 83 and the rotating arm 5 of the second rotary solenoid 52
A connecting link 103 is interposed between the connecting link 103 and the second rotary solenoid 52, and when the second rotary solenoid 52 is energized, the rotating arm 54 is rotated clockwise in FIG. ruler 90
The ruler support body 83 having the following is moved slightly to the right perpendicular to the cloth feeding direction. The second rotary solenoid 52, the connecting link 103, and the like constitute operating means for moving the hem ruler 90.

FIG. 16 is a block circuit diagram showing the electrical configuration of the hem sewing device of this embodiment, in which signals from the reed switch 73, stitch number setting device 111, stitch number counting device 112 and forward/backward movement switch 113 are input. The data signal from the input port 114 is output to the central processing unit (hereinafter referred to as CPU),
Accordingly, the CPU 115 performs calculations, and the processing results are output to the output port 116, and the output from the output port 116 operates the first and second rotary solenoids 51, 52 as appropriate.

Next, the operation of the hemline sewing device configured as described above will be explained. Now, before hemming starts, the first and second rotary solenoids 51 and 52 are demagnetized. For this reason,
As shown in FIG. 8, the spring force of the spring 102 on the step screw 98 acting on the interlocking lever 99 causes the interlocking lever 99 to be placed in one rotational position, and the movable body 88 having the hem ruler 90 is moved. The lower guide plate 9 of the hem ruler 90 is arranged on the cloth feeding side.
The guide tongue piece 94a of 4 is located in the groove 1 on the lower surface of the presser foot 8.
It is entering within 1. Further, due to the action of the spring 55, the ruler support 83 is placed at the right position via the arm 54 and the connecting link 103, and the hemming ruler 90 is placed at the right position together with the movable body 88. It is close to the guide surface 94b of the lower guide plate 94 of the ruler 90 and the left side surface 63a of the hemming auxiliary body 63. At this time, the support shaft 42 can be adjusted to move to the right or left by turning the adjusting screw 46 to the right or left using the knob 46a in advance so that the guide surface 94b is located substantially on the cloth feeding direction line. The left and right positions of the ruler support 61 having the hemming ruler 90 are adjusted in advance.

In order to start hem stitching in this state, first, the forward and backward movement switch 113 shown in FIG. 16, which is provided on a part of the sewing machine frame 1, is operated to close. In this way, a signal based on the operation is input to the CPU 115 via the input port 114, a predetermined signal is output from the CPU 115 to the output port 116, and the first rotary solenoid is output from the output port 116. An excitation current is output to 51. Therefore, the first rotary solenoid 51 is energized and the rotating arm 53 moves to the twelfth rotary solenoid against the spring force of the spring 102 on the step screw 98.
It is rotated clockwise in the figure. Therefore, the connecting link 100 is pulled and the interlocking lever 99 is rotated to the position shown in FIG.
is moved horizontally along the ruler guide shaft 87 to a non-active position where it abuts against the cloth feeding side wall 83b of the ruler support 83, and the guide tongue piece 94b of the hemming ruler 90 touches the groove 11 of the presser foot 8. Move forward from the position. At the same time, the presser foot 8 is raised from the lower working position to the upper non-working position using a foot pedal (not shown).

When the movable body 88 is placed in the inactive position,
The base 91 of the hem ruler 90 comes off the guide piece 83c of the ruler support 83 and the hem ruler 90 can be rotated upward, so that the hem ruler 90 is moved as shown by the two-dot chain line in FIG. 90 to the upper position, and as shown in FIG. The second bent part B is accommodated between the lower guide plate 94 and the upper guide plate 93, and the outer surface of the second bent part B is aligned with the cloth receiver 95. Note that the cloth receiver 95 is moved and adjusted in advance to an appropriate position according to the required hem width (W in FIG. 2).

After setting the work cloth C as described above, return the hem ruler 90 to the downward horizontal position.

At this time, since the first rotary solenoid 51 has already been demagnetized, the interlocking lever 99 is rotated clockwise by the spring force of the spring 102 on the step screw 98, and the hemming ruler 90 is moved together with the movable body 88. It is horizontally moved to the operating position regulated by the wall portion 83a of the support body 83. Then, the guide tongue piece 94a of the hem ruler 90 enters into the groove 11 of the presser foot 8.

When the sewing machine starts operating in this state, the feed dog 4 and the presser foot 8 cooperate to move the workpiece cloth C set on the hem ruler 90 as shown in FIG.
is the guide surface 9 of the lower guide plate 94 along the cloth feeding direction line.
4b toward a sewing point by the sewing machine needle 9, and at that sewing point hemming is performed on the right edge D and the first folded portion A of the work cloth using an overlock stitch. In addition, in FIG. 15, for ease of understanding, the thickness of the work cloth C, the guide surface 94b of the hemming ruler 90, and the hemming auxiliary body 63 are shown.
The distance between the left side surface 63a and the like is exaggerated.

In this way, when the side-joining portion F is fed to the position where it is guided by the hem ruler 90 as shown in FIG. At the same time, a recess I is formed on the inner surface of the stepped portion G on the cloth delivery side. When the step G reaches the position of the detection piece 70, the step G causes the detection piece 70 to sink into the recess 69 against the spring force of the coil spring 76, and the detection shaft 68 becomes a permanent magnet. and moved to the right. As a result, a predetermined signal is output from the reed switch 73, the stitch number counting device 112 starts counting the number of stitches, and the concave portion I and step portion G move toward the needle passing point along the guide surface 94b. Sent. Then, the number of stitches is determined by the number of stitches setting device 11.
1, when the workpiece cloth C is fed a predetermined length and the recess I reaches the needle passage point, the CPU 115 outputs a predetermined signal and activates the second rotary solenoid. 52 is energized. As shown in FIG. 15, the left side surface 63a of the hemline auxiliary body 63 engages with the stepped portion G, so that the hemline auxiliary body 63 is rotated while the pressing piece 78 is inserted thereinto.

Due to the excitation of the second rotary solenoid 52, the rotating arm 54 is rotated counterclockwise in FIG. is moved slightly to the left. Therefore, the guide surface 94b of the hem ruler 90 shifts slightly to the left as shown by the two-dot chain line in FIG. The recess I and step G are located on the needle passage point. Therefore, the recessed portion I can be sewn.

Thereafter, when the stitch number counting device 112 further counts the predetermined number of stitches, that is, when the sewing of the concave portion I and the step portion G is completed, the second rotary solenoid 56 is demagnetized again and the spring force of the spring 55 The guide surface 94b of the hem ruler 90 moves to the right.

As described above, in this hem sewing device, the guide surface 94b that guides the first folded portion A of the work cloth C engages with the inner surface of the first folded portion A. Movement of the bent portion A portion to the left is restricted, and it is impossible that a recessed portion H located on the outer surface of the first bent portion A as shown in FIG. 6 is formed. Therefore, the occurrence of unstitching due to the presence of the recess H can be reliably prevented.

In addition, in this hem sewing device, when the concave portion I and the subsequent stepped portion G shown in FIG. The bending part A becomes straight due to the elasticity of the work cloth C itself, so that the concave part I will not move to the right of the needle passing point, and the possibility of overhanging can be reliably prevented. . In other words, without the hemming ruler 90 moving to the left,
If the fabric is fed in the state shown by the solid line in Fig. 5, the needle will fall into the recess I, and when the work cloth C is brought into the state shown in Fig. 4, a large seam will appear on the surface of the work cloth C. become.

In the above embodiment, the detection piece 70 detects the presence of the step G, and as a result, the presence of the recess I connected to the step G is detected. Alternatively, the presence of the recess I may be directly detected. Further, in the embodiment, the support shaft 42 for supporting the hem ruler 90 is attached to the support body consisting of the mounting base 23 and the device frame 25, but it may be attached directly to the sewing machine frame 1.

Effects of the Invention As exemplified in the embodiments above, the present invention provides a hemming ruler that is arranged with a cloth passage gap apart from a work cloth support surface and is used as a hem ruler for a work cloth to be bent twice for hemming. A lower guide plate is formed with a guide surface that extends along the cloth feed direction line passing through the needle passing point to engage with the inner surface of the bent part and guide the work cloth, and the lower guide plate is processed. and an upper guide plate disposed with a gap capable of accommodating the second folded part of the fabric, and the first part of the work fabric guided by the guide surface of the hem ruler. A detection means is provided for detecting the presence of a recess formed on the inner surface of the bent portion, and based on the detection by the detection means, when the recess passes through the needle passing point, the hemming ruler is moved so that its guide surface is By providing the actuating means for moving the hem away from the inner surface of the first bent portion, an excellent effect is achieved in that both hem-sewing and over-overlocking can be reliably prevented.

[Brief explanation of the drawing]

Fig. 1 is a partial perspective view of a sewn product with hem stitching, Fig. 2 is a partially enlarged perspective view of the same, Fig. 3 is a sectional view showing the hem sewn state, and Fig. 4 is hem stitching. FIG. 5 is a front view showing a conventional hem sewing guide device, and FIG. 6 is an enlarged sectional view showing the conventional hem sewing guide state. Fig. 7 and subsequent figures show an embodiment embodying the present invention, in which Fig. 7 is a partially cutaway side view of a sewing machine equipped with a hemming guide device, and Fig. 8 is a use of the hemming guide device. A plan view showing the state, FIG. 9 is a plan view showing the unused state, FIG. 10 is a sectional view showing a configuration for preventing rotation of the support shaft, and FIG. 11 is adjusting the left and right position of the support shaft. A sectional view showing the configuration for
Fig. 12 is a front view of the hem-pulling guide device, Fig. 13 is a bottom view showing the hem-pulling auxiliary body, Fig. 14 is a sectional view showing the hem-pulling ruler moved to the cloth feeding side, Fig. 15 The figure is an enlarged cross-sectional view showing the guiding state of the work cloth, and FIG. 16 is a block circuit diagram showing the electrical configuration of the hem sewing device of this embodiment. Sewing machine frame...1, Feed dog...4, Presser foot...8, Work cloth support surface...10, Second rotary solenoid...52, Permanent magnet...71, Reed switch...73, Hemming Ruler...90, Upper guide plate...93, Lower guide plate...94, Guide surface...94b, CPU...115, First bending part...
A. Second bent part... B. Processed cloth... C. Concave part...
I.

Claims (1)

[Claims] 1. The workpiece cloth C passes through the needle passage point and is placed on the workpiece cloth support surface 10.
The work cloth feed means 4, 8 for transferring the work cloth in one direction on the upper side, and the work cloth feed means 4, 8 on the cloth feed side of the work cloth feed means 4, 8, the above-mentioned A hemming ruler 90 supported movably in a direction perpendicular to the cloth feeding direction by the work cloth feeding means 4 and 8;
The needle is disposed across a cloth passing gap from the needle and engages with the inner surface of the first folded portion A of the work cloth C which is bent twice for hemming, thereby guiding the work cloth C. A lower guide plate 94 on which a guide surface 94b extending along the cloth feeding direction line passing through the passing point is formed, and a gap capable of accommodating the second bent portion B of the work cloth C is provided to the lower guide plate 94. Upper guide plate 93 arranged
and formed on the inner surface of the first bent portion A of the work cloth C guided by the guide surface 94b of the hem ruler 90. detection means 71 and 73 for detecting the presence of the recess I, and based on the detection by the detection means 71 and 73,
An actuating means 52 and the like is provided for moving the hemming ruler 90 so that its guide surface 94b separates from the inner surface of the first bending part A when the recess I passes the needle passing point. Features: Sewing machine hemming device.