JPH09135981A - Sewing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sewing machine capable of enlarging the scope of sewing work compared to a conventional-type sewing machine. SOLUTION: This sewing machine is composed of a sewing mechanism 10 for forming a seam on an object to be sewed by shuttling back and forth a needle 4 in the center line of the needle, a rotary drive mechanism 20 for relatively rotating both object to be sewed and sewing mechanism 10 centering around a rotary axis RC in parallel with the center line of the needle 4, a rectilinear drive mechanism 20 for relatively moving both object to be sewed and sewing mechanism 10 in a straight line so that the rotary axis RC moves in a single straight line L orthogonal with the center line of the needle 4, and a control device for controlling the action of the rotary drive mechanism 20 and the rectilinear drive mechanism 30 in such a manner that the needle 4 relatively moves from a present position on the object to be sewed to an objective position only by the synthesis of the rotary motion and the rectilinear motion.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sewing machine having a mechanism for relatively moving a sewing object and a sewing needle.

[0002]

2. Description of the Related Art As a sewing machine of this type, as shown in FIG. 5B, the embroidery frame 1 is moved in the longitudinal direction of the arm 2 (Y-axis direction) and in the direction orthogonal thereto (X-axis direction). It is known to sew a predetermined pattern on a work cloth (not shown) held by the frame 1.

[0003]

In the above-mentioned conventional sewing machine, since the moving range of the embroidery frame 1 in the Y-axis direction is limited by the support columns 3, the range of the diameter D0 equal to the distance from the sewing needle 4 to the support columns 3 is obtained. The pattern can be sewn only inside. In addition to Japanese Unexamined Patent Publication (Kokai) No. 5-123464 and Japanese Unexamined Patent Publication (Kokai) No. 3-1993089, it is possible to rotate the embroidery frame around an axis parallel to the center line of the sewing needle in addition to the linear movement in the two directions. Sewing machine is described. However, these sewing machines only add rotational movement to two linear movements to correct the relative position between the work cloth and the sewing needle. As long as such drive control is performed, the sewing range is limited due to the limitation of the movement amount in the Y-axis direction, and the above-mentioned problems cannot be solved.

An object of the present invention is to provide a sewing machine capable of expanding the sewing range as compared with the conventional one.

[0005]

According to a first aspect of the present invention, a sewing mechanism that reciprocates a sewing needle in the direction of its center line to form a stitch on a sewing object, and a sewing mechanism that is parallel to the center line of the sewing needle. A rotation drive mechanism for relatively rotating the sewing object and the sewing mechanism about a rotation axis, and the rotation axis moves on a single straight line orthogonal to the center line of the sewing needle. A linear drive mechanism that relatively linearly moves the sewing object and the sewing mechanism, and the sewing needle moves from a current position on the sewing object to a target position only by combining the rotary motion and the linear motion. The above-described object is achieved by a sewing machine including a controller that controls the operations of the rotary drive mechanism and the linear drive mechanism so as to move relative to each other.

According to the second aspect of the present invention, the holding member for the sewing object rotatably supported about the rotation axis parallel to the center line of the sewing needle, and the holding member rotating about the rotation axis. A combination of a rotary drive mechanism, a linear drive mechanism that linearly moves the holding member so that the rotary axis moves on a single straight line orthogonal to the center line of the sewing needle, and the rotary motion and the linear motion. The sewing machine is provided with a controller that controls the operations of the rotary drive mechanism and the linear drive mechanism so that the sewing needle relatively moves from the current position on the sewing object to the target position only by the sewing machine. Achieve the purpose.

According to the above invention, even if there is a structure such as a strut on the side of the sewing object, the restriction of the sewing range can be alleviated by setting the direction of the linear movement so as to avoid it. According to a third aspect of the present invention, in the sewing machine according to the first or second aspect, an arm that holds the sewing needle at one end side and a column that supports the other end side of the arm from a direction parallel to the center line are provided. It is characterized in that the direction connecting the one end and the other end of the arm is orthogonal to the direction of the linear movement by the linear drive mechanism. According to the invention,
Since the sewing object does not move in the longitudinal direction of the arm, the sewing range can be secured over a width approximately twice the size from the sewing needle to the support.

According to a fourth aspect of the present invention, in the sewing machine according to the first or second aspect, the sewing needle is moved from the n-th (where n is a natural number) needle drop point on the sewing object to the (n + 1) -th needle drop point. In the meantime, the controller controls the rotary drive mechanism and the linear drive so that the distance between the n-th needle drop point and the center line of the sewing needle does not exceed the linear distance between the two needle drop points. It controls the operation of the mechanism. According to the present invention, while the sewing needle relatively moves between the pair of needle drop points on the sewing object, there is no possibility that the thread is pulled out from the sewing needle beyond the distance between the needle drop points. .

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described with reference to FIGS. Note that the same parts as those of the conventional example shown in FIG. FIG.
Shows a schematic configuration of the sewing machine according to the present embodiment, 10 is a sewing mechanism, 20 is a rotary drive mechanism, and 30 is a linear drive mechanism. The sewing mechanism 10 has a needle drive motor 11 and a conversion mechanism (not shown) that converts the rotational movement of the needle drive motor 11 into a reciprocating movement of the sewing needle 4 in the direction of the center line (the vertical direction in the drawing). Various well-known mechanisms using cams, links, etc. may be used as the conversion mechanism, and details thereof will be omitted here. Also,
The sewing mechanism 10 also includes a rotary hook (not shown) that supplies the lower thread in association with the upper thread supplied by the sewing needle 4. The rotary hook is always held immediately below the sewing needle 4.

The rotary mechanism 20 transmits the rotary motion of the frame rotary motor 21 to the driven pulley 23 via the belt 22, and the rotary motion of the driven pulley 23 is transferred to the outer periphery of the embroidery frame 1 via a gear mechanism (not shown). It is transmitted to the gear 1a. The embroidery frame 1 is
It is rotatably supported on the movable base 31 about the rotation axis RC. Therefore, the transmission of the rotation to the gear 1a causes the embroidery frame 1 to rotate about the rotation axis RC. Rotation axis RC
Is parallel to the center line of the sewing needle 4, and the sewing needle 4 and the rotation axis RC are at the same position in the longitudinal direction (Y-axis direction) of the arm 2. The embroidery frame 1 may be directly driven around the rotation axis RC by a motor without passing through a power transmission means such as the belt 22. The motor 21, the pulley 23, and the power transmission mechanism from the pulley 23 to the gear 1a can be supported by the movable table 31.

The linear movement mechanism 30 includes a movable base 31 described above.
And a drive unit 32 that reciprocates the same in the X-axis direction. The X-axis direction corresponds to a direction orthogonal to both the center line direction of the sewing needle 4 and the longitudinal direction of the arm 2. The drive unit 32 includes a rack 33 extending in the X-axis direction, a pinion 34 that meshes with the rack 33, and an X-axis drive motor 35 that rotates the pinion 34. The rack 33 moves the movable table 31 at a position where the meshing with the pinion 34 is not limited.
Connected with. Therefore, the movable base 31 linearly reciprocates in the X-axis direction by the rotation of the X-axis drive motor 35. At this time, the rotation axis RC moves on a virtual straight line L passing through the center line of the sewing needle 4 and extending in the X-axis direction.

The structure of the control system of the sewing machine shown in FIG. 1 is shown in FIG. In the figure, reference numeral 40 denotes a CPU that executes operation control and calculation of each part of the sewing machine necessary for sewing work. The CPU 40
For example, it is configured by combining a microprocessing unit and peripheral circuits necessary for its operation. CPU40
Is connected to the data input device 41 and the storage device 42, and is also connected to the above-described motors 11, 21, and 35 via the sewing needle control circuit 43, the frame rotation control circuit 44, and the X-axis drive control circuit 45. . Sewing data is input from the data input device 41, and the data is appropriately stored in the storage device 42. The sewing data includes, for example, information for specifying the position of a needle drop point (point where the sewing needle 4 penetrates through the work cloth) for each needle on the work cloth, the color and type of the sewing thread, and the like. The embroidery data is provided from, for example, a ROM card or a personal computer configured as an embroidery data creation device. When the user gives an instruction to start the sewing work, the CPU 40 outputs control signals for the needle drive motor 11, the frame rotation motor 21, and the X-axis drive motor 35 based on the given sewing data. These control signals are converted into drive signals for the motors 11, 21, and 35 by the control circuits 43 to 45, and the motor 1 is driven according to these drive signals.
1, 21, 35 are rotationally driven in a predetermined direction by a predetermined amount. As a result, the sewing needle 4 reciprocates up and down and relatively moves on the work cloth at a speed synchronized with the reciprocating motion.

Next, the driving principle of the embroidery frame 1 by the CPU 40 will be described with reference to FIG. The left-right direction in FIG. 3 corresponds to the X-axis direction in FIG. A straight line passing through the center line of the sewing needle 4 and extending in the X-axis direction is shown by a chain line L as in FIG. In FIG. 3A, the current needle drop point (n-th needle drop point) for the work cloth on the embroidery frame 1 is P.
Assuming that a and the next needle drop point (n + 1st needle drop point) are Pb, the position NP of the sewing needle 4 at that time coincides with the needle drop point Pa. In order to perform the desired sewing from this state, it is necessary to move the next needle drop point Pb to the position NP. For this purpose, an angle θ formed by the line segment connecting the rotation axis RC of the embroidery frame 1 and the next needle drop point Pb and the X-axis direction
By rotating the embroidery frame 1 only, the position NP of the sewing needle 4 and the needle drop point Pb are aligned in the X-axis direction as shown in FIG. 3B.
Then, as shown by the arrow in FIG.
The needle drop point Pb is moved to the position NP of the sewing needle 4 by driving in the axial direction.
Move up to In this way, the sewing needle 4 is relatively moved from the current position on the work cloth to the target position only by combining the rotational movement of the embroidery frame 1 about the rotation axis RC and the linear movement in the X-axis direction. . Although the rotary motion and the linear motion are separately described above, the rotary motion and the linear motion are executed in parallel during actual sewing. The needle drop point P
The distance d between a and Pb is actually the diameter D1 of the embroidery frame 1.
Although it is much smaller than that shown in FIG. 5A, it is exaggerated in FIG. 3 for convenience of understanding.

Here, in the state of FIG. 3A, the needle drop point Pa
When moving the sewing needle 4 from P to Pb relative to the needle drop point P
The distance between a and the sewing needle 4 does not exceed the above distance d, in other words, the needle drop point Pa does not deviate from the area (hatching area) H within the radius d from the position NP of the sewing needle 4. The movement amount of the embroidery frame 1 is limited. When the needle drop point Pa deviates from the area H, the upper thread is pulled out from the sewing needle 4 more than the amount necessary to pass the sewing thread between the needle drop points Pa and Pb, and the extra thread is removed from the needle drop points Pa and Pb. The quality of the embroidery deteriorates due to the looseness.

In FIG. 3, the case where the needle drop point is moved from Pa to Pb at one time is taken as an example, but these points Pa to Pb are taken.
If you want to form a straight and continuous seam between
As shown in FIGS. 4A to 4E, the embroidery frame 1 is rotated in a fixed direction (counterclockwise in the illustrated example), and the position NP of the sewing needle 4 is aligned with the line connecting the points Pa and Pb. Drive in the X-axis direction is controlled so that the needles do not come off and the intervals between the needle drop points are equal. In this case, since the drive speed needs to be changed sequentially, it is advisable to set either the angular speed of the rotary motion or the speed of the linear motion to a constant speed in order to simplify the control.

According to the above embodiment, the embroidery frame 1 and the sewing needle 4 are combined only by the combination of the linear motion of the arm 2 in the X-axis direction orthogonal to the longitudinal direction and the rotary motion about the rotation axis RC. Since a predetermined relative movement is given between them, it is not necessary to drive the embroidery frame 1 in the Y-axis direction. Therefore, as shown in FIG. 5A, the diameter D1 of the sewing range of the embroidery frame 1 can be increased to almost twice the diameter D0 of the conventional case shown in FIG.

In the above embodiment, the embroidery frame 1 corresponds to the holding member of the sewing object, and the CPU 40 corresponds to the control device. In the above embodiment, the embroidery frame 1 is given a linear motion and a rotary motion, but either one or both motions may be given to the sewing mechanism, that is, the sewing needle or the rotary hook.

[0018]

As described above, according to the present invention,
Since the sewing needle is moved relative to the target position from the current position on the sewing object only by combining the single linear movement and the rotational movement, the sewing object can be moved closer to the structure such as the strut. It is not necessary to separate them, and it is possible to sew a wider area than before. According to the third aspect of the present invention, in particular, the restriction on the sewing range due to the support columns is relaxed, and a sewing area having a diameter approximately twice that of the conventional case can be secured. According to the invention of claim 4, there is no possibility that the sewing thread is unnecessarily pulled out while the sewing needle relatively moves between the pair of needle drop points of the sewing object. Prevents loosening and ensures beautiful sewing.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a schematic configuration of a sewing machine according to an embodiment of the present invention.

FIG. 2 is a block diagram of a control system of the sewing machine shown in FIG.

FIG. 3 is a diagram for explaining a driving principle of an embroidery frame by the sewing machine of FIG.

FIG. 4 is a diagram showing the operation of the embroidery frame when forming continuous stitches in one direction on the work cloth by the sewing machine of FIG. 1.

FIG. 5 is a diagram for comparing sewing ranges of sewing machines,
(A) shows the sewing range by the sewing machine of the present invention, and (b) shows the sewing range by the conventional sewing machine.

[Explanation of symbols]

 1 ... Embroidery frame 2 ... Arm 3 ... Strut 4 ... Sewing needle 10 ... Sewing mechanism 20 ... Rotation drive mechanism 30 ... Linear drive mechanism 40 ... CPU NP ... Sewing needle position Pa, Pb ... Needle drop point

Claims (4)

[Claims] 1. A sewing mechanism that reciprocates a sewing needle in the direction of its center line to form a stitch on a sewing object; and a sewing object about a rotation axis parallel to the center line of the sewing needle. A rotation drive mechanism that relatively rotationally moves the sewing mechanism, and the sewing target and the sewing mechanism such that the rotation axis moves on a single straight line orthogonal to the center line of the sewing needle. A linear drive mechanism for relatively linearly moving the sewing needle, and the rotary drive so that the sewing needle relatively moves from a current position on the sewing object to a target position only by combining the rotational motion and the linear motion. A sewing machine comprising a mechanism and a control device for controlling the operation of the linear drive mechanism. 2. A holding member for a sewing object rotatably supported around a rotation axis parallel to a center line of a sewing needle, and a rotation drive mechanism for rotating the holding member about the rotation axis. A linear drive mechanism that linearly moves the holding member so that the rotation axis moves on a single straight line orthogonal to the center line of the sewing needle; and the sewing needle only by combining the rotational movement and the linear movement. A sewing machine which controls the operations of the rotary drive mechanism and the linear drive mechanism so that the machine relatively moves from the current position to the target position on the sewing object. 3. An arm for holding the sewing needle at one end side, and a column for supporting the other end side of the arm from a direction parallel to the center line, and connect the one end and the other end of the arm. The sewing machine according to claim 1 or 2, wherein the direction and the direction of the linear movement by the linear drive mechanism are orthogonal to each other. 4. The n-th needle drop point and the sewing stitch while the sewing needle moves from the n-th needle drop point (where n is a natural number) on the sewing object to the (n + 1) -th needle drop point. 2. The control device controls the operations of the rotary drive mechanism and the linear drive mechanism so that the distance from the center line of the needle does not exceed the linear distance between the two needle drop points. Or the sewing machine described in 2.