JPH11137880A - Sewing machine frame with excellent assemble performance and rigidity - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase rigidity of a sewing machine frame and to improve twist by the vertical load on a needle and sewing at the upper part of a tower, by integrally forming a bed-arm-tower in a laid U-shaped section by synthetic resin and placing an enhancing plate at a specific position on the bed. SOLUTION: A bed-arm-tower is integrally formed of synthetic resin in a laid U-shape section with one side opening. At the bed side of a corner part A of the bed 2 and the tower 4, an enhancing plate 5 which connects the upper part 8a with the lower part 8b of an open face of the bed is equipped to fix. Further, on the base part of the arm shaped bed, an enhancing plate is equipped to connect and fix the upper and lower parts of the open face of the bed and the arm shaped bed part. Thus twist by the vertical load by the reciprocating needle is restricted to remarkably reduce the twist on the arm 3 causing to remarkably improve swing of the upper part of the tower 4. Further, the displacement of the arm front part is made be only the vertical direction so as not to generate the horizontal displacement at the needle point.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sewing machine frame in which a bed, an arm and a tower are integrally formed of a synthetic resin (including a fiber-reinforced synthetic resin).
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sewing machine frame which is easy to assemble a drive and control mechanism for controlling a sewing operation and has excellent rigidity.

[0002]

2. Description of the Related Art A sewing machine is required to be able to perform a smooth sewing operation. In order to ensure this smooth sewing operation, it is necessary to reduce vibration and displacement of the needle point, and a high rigidity is required for the sewing machine frame. The rigidity of the sewing machine is for preventing a reaction force due to the reciprocating motion of the needle of the sewing machine. The bed 2, the arm 3, and the tower 4 as shown in FIG. 9 are integrally formed inside the cover of the sewing machine. Is held by the sewing machine frame 1 that has been set. A reinforcing member 11 is provided inside the bed 2 of the synthetic resin sewing machine frame 1 to improve rigidity. Note that the tower 4 refers to the entire upright portion on the right side of the dotted line in FIG. 9, and the bed 2 and the arm 3 refer to portions protruding from the upright portion on the left side of the dotted line in FIG. 9. The same applies to the following description.

[0003] On the other hand, there is a high demand for cost reduction and weight reduction of the sewing machine, and the sewing machine frame was originally made of cast iron, but has been changed to aluminum. Recently, frames made of synthetic resin, particularly fiber-reinforced synthetic resin, have been used for further cost reduction and weight reduction.

Further, in order to reduce the cost of the sewing machine, the assembling work of the sewing machine occupies a large weight.
This is because the sewing machine frame has a rigid box-shaped structure in order to obtain high rigidity, and it is necessary to store mechanisms such as drive and control for sewing operations inside the sewing machine frame. Is so small that the assembling work of the sewing machine involves considerable difficulty. In order to assemble these drive and control mechanisms, an opening 1 for storing drive and control mechanisms as shown in FIG.
0a, 10b and 10c are provided respectively. If these openings 10a, 10b, and 10c are made large, the rigidity of the sewing machine frame is reduced. Therefore, these openings are the minimum openings required for assembly.

Moreover, assembling a mechanism for driving, controlling, and the like from the opening for storing the mechanism requires time and requires skill. Therefore, in order to greatly improve the assemblability, a structure in which one side of the box-shaped structure is completely removed as shown in FIG. 10, that is, a sewing machine frame in which one side is opened and the cross section is formed in a U-shape is used. Proposed

[0006]

However, the above-described sewing machine frame having one side surface opened and a U-shaped cross section has a problem that the rigidity is remarkably reduced, and has not been put to practical use. That is, in the case of a sewing machine frame in which one side surface is opened and the cross section is formed in a U-shape, in the reciprocating motion of the needle, which is a normal sewing operation, not only the vertical direction but also the load applied on the reciprocating line of the needle. As shown in FIG. 8A, a so-called swaying phenomenon occurs in the horizontal direction at the upper part of the tower 4 and the vibration becomes severe. As a result,
As the needle tip is displaced in the horizontal direction, the vibration of the needle tip also increases, and smooth sewing becomes difficult.

To improve the rigidity of the sewing machine frame having such a shape, it is possible to solve the problem to some extent by increasing the thickness of the frame by using a metal frame such as cast iron or aluminum. However, there is a problem that the cost of manufacturing the frame increases and the weight of the frame itself increases.

On the other hand, in the case of a synthetic resin frame, the synthetic resin has a significantly lower rigidity than metal materials such as cast iron and aluminum. Therefore, a sewing machine frame having an open side and a U-shaped cross section is used. There is a problem that it cannot be used.

Therefore, according to the present invention, it is easy to assemble mechanisms such as drive and control, and the bed, arm and tower are made of synthetic resin,
In particular, it is an object of the present invention to provide a sewing machine frame which is integrally formed of a fiber reinforced synthetic resin and has excellent rigidity.

[0010]

Means for Solving the Problems In order to achieve the above-mentioned object, the present inventors have formed a bed, an arm and a tower, each of which has an open side and a U-shaped cross section, by integral molding with a synthetic resin. Intensive study was conducted to improve the rigidity of the sewing machine frame. A rigid reinforcing plate is disposed at a specific location of the bed of the sewing machine frame having the one side open and the cross section formed in a U-shape to fix the upper and lower portions of the open surface of the bed. As a result, the present inventor has obtained a finding that the horizontal displacement of the needle tip can be reduced by suppressing the swinging phenomenon of the sewing machine frame, and completed the present invention. The specific portion is the bed side of the corner portion between the bed and the tower, and further, in the case of a sewing machine frame having an arm-shaped bed portion in which the tip of the bed is formed above the installation surface of the sewing machine frame, the arm It is the arm-shaped bed part side of the base of the bed part.

Further, the course leading to the present invention will be described.
It was considered that the tail swing phenomenon and the horizontal deformation of the sewing machine frame were caused by the asymmetry of the rigidity of the frame having the U-shaped cross section in which one side of the box-shaped frame was removed. That is, with respect to the load of the reciprocating movement of the needle for the sewing operation,
In a frame having a box-shaped structure, only deformation in the vertical direction occurs, whereas in a frame having a U-shaped cross-section, one side surface is opened, so that a twist as shown in FIG. It was concluded that this torsion caused the U-shaped frame to be deformed in the horizontal direction, and as a result, the sewing machine frame to be swung.

A detailed structural analysis was performed on the frame having a U-shaped cross section using the finite element method. The result is shown in FIG.
Shown in Note that the broken line in FIG. 7 shows the state before the load (no deformation), and the solid line shows the deformed state after the load. Reinforcement plates are shaded. As shown in FIG. 7, torsion with respect to the sewing machine frame occurs in the arm 3 and the bed 2 due to the vertical load due to the reciprocating movement of the needle. This twist is greater in the arm 3 than in the bed. It has been found that the torsion generated in the bed 2 is added to the arm 3, the torsion in the arm is amplified, the assembling phenomenon occurs at the upper part of the tower 4, and the vibration of the arm is also increased accordingly. .

The hip swing phenomenon is a result of this torsion, and thus it has been concluded that the torsional deformation to this vertical load should be suppressed. From this point of view, as a result of conducting experiments with further intensive studies,
It has been found that improving the rigidity of the bed is more effective for torsional deformation, and can prevent the butt swing phenomenon at the top of the tower. That is, as shown in FIG.
It has been found that connecting the upper part and the lower part of the open surface of the bed part to the bed side of the corner part between the bed 2 and the tower 4 and fixing the same effectively suppresses torsional deformation. A plate of high rigidity such as steel may be used as the reinforcing plate.

Further, in the case of a sewing machine frame having an arm-shaped bed portion in which the leading end of the bed is formed above the installation surface of the sewing machine frame, a reinforcing plate is provided as an effective place for suppressing torsion. Further analysis and experimentation revealed that it was at the base. That is, as shown in FIG. 6, the reinforcing plate 6 may be fixedly provided at the base of the arm-shaped bed part 7 at the base of the arm-shaped bed part by connecting the upper part and the lower part of the open surface of the arm-shaped bed part. It was found that the torsional deformation was suppressed very effectively.

According to a first aspect of the present invention, there is provided a sewing machine frame in which one side is opened and a cross section is formed in a U-shape, and an arm and a tower are integrally formed of synthetic resin. And a reinforcing plate for connecting the upper part and the lower part of the open surface of the bed is fixedly provided on the bed side of the corner part between the bed and the tower. As shown in FIG. 4, in a sewing machine frame 1 having one side open and a U-shaped cross section, an upper portion 8a of an open surface of the bed is provided on the bed side of a corner portion A between the bed 2 and the tower 4. By fixedly providing the reinforcing plate 5 that connects the lower portion 8b, horizontal deformation and butt swing of the sewing machine frame can be suppressed.

According to a second aspect of the present invention, in the configuration of the first aspect of the present invention, the distal end of the bed has an arm-shaped bed formed above a surface on which the sewing machine frame is installed. Is what you do. As shown in FIG. 1, by forming the arm-shaped bed portion 7 above the installation surface of the sewing machine frame at the tip end of the bed 2, handling of sewing is facilitated.

According to a third aspect of the present invention, in the configuration of the second aspect, the reinforcing plate is provided on an arm-shaped bed side of a base of the arm-shaped bed and an open surface of the arm-shaped bed. The upper part and the lower part are connected and fixedly provided. By changing the installation position of the reinforcing plate from the bed side of the corner portion A of the bed 2 and the tower 4 to the arm-shaped bed portion of the base B of the arm-shaped bed portion as shown in FIG. Top 9 of the open side of the
By fixing and providing the reinforcing plate 6 connecting the a and the lower portion 9b, the horizontal deformation and the butt swing phenomenon of the sewing machine frame can be effectively suppressed.

According to a fourth aspect of the present invention, in addition to the configuration of the second aspect of the invention, as shown in FIG. 3, a reinforcing plate is provided on the bed side of the corner A between the bed 2 and the tower 4 and on the arm. The upper and lower sides of the open surface of the bed and the arm-shaped bed are connected to and fixed to both the arm-shaped bed at the base of the arm-shaped bed and the arm-shaped bed at the base of the arm-shaped bed. By providing the reinforcing plates 5 and 6, the horizontal deformation and the butt swing phenomenon of the sewing machine frame can be more effectively suppressed.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described with reference to illustrated examples. FIG. 1 is a diagram showing a sewing machine frame according to an embodiment of the present invention in which a reinforcing plate is fixed to a sewing machine frame having one side opened, and FIG. 5 shows a structural analysis result of the sewing machine frame by a finite element method. . The present embodiment is a sewing machine frame having an arm-shaped bed portion in which a tip portion of a bed is formed above an installation surface of the sewing machine frame, and a reinforcing plate is provided on a bed side of a corner portion between a bed and a tower. It is. The sewing machine frame of the present embodiment uses a fiber-reinforced synthetic resin, and the dimensions are as follows.・ Height of sewing machine frame: 400 mm ・ Length of upper part of sewing machine frame: 438 mm ・ Length of lower part of sewing machine frame: 538 mm ・ Width of sewing machine frame: 85 mm ・ Thickness of sewing machine frame: 4-6 mm ・ Arm length : 250mm ・ Arm thickness: 110mm ・ Bed length: 350mm ・ Bed thickness: 110mm ・ Arm bed length: 220mm ・ Arm bed thickness: 75mm ・ From the installation surface of the arm bed Standing height: 45mm

As shown in FIG. 1, the reinforcing plate was fixed to the bed side of the corner portion A of the bed 2 and the tower 4 by connecting the upper part 8a and the lower part 8b of the open surface of the bed. As the reinforcing plate, a steel plate having a thickness of 2 mm and a width of 30 mm was used.

The structure of the sewing machine frame of this embodiment is analyzed using the finite element method, and the results are shown in FIG. FIG.
The broken line indicates the state before the load (no deformation), and the solid line indicates the deformed state after the load. Reinforcement plates are shaded. As shown in FIG. 5, the torsion caused by the vertical load caused by the reciprocation of the needle is restrained by the reinforcing plate 5 of the bed.
The torsion in the arm 3 is also significantly reduced, and the reduction in the swinging of the upper part of the tower 4 is significantly improved. Further, the displacement of the front portion of the arm is only in the vertical direction, and no horizontal displacement occurs at the needle tip.

Another embodiment of the present invention will be described with reference to the drawings. FIG. 2 is a diagram showing a sewing machine frame according to another embodiment of the present invention in which a reinforcing plate is fixed to a sewing machine frame having one open side, and FIG. 6 shows a structural analysis result of the sewing machine frame by a finite element method. Is shown. The present embodiment is a case where the reinforcing plate 6 is provided on the side of the base of the arm-shaped bed portion 7 on the side of the arm-shaped bed portion using a sewing machine frame of the same specifications and the same material as that of the previous embodiment. As shown in FIG. 2, the reinforcing plate 6 is fixed to the arm-shaped bed portion side B at the base of the arm-shaped bed portion 7 by connecting an upper portion 9a and a lower portion 9b of the open surface of the arm-shaped bed portion. As the reinforcing plate, a steel plate having a thickness of 2 mm and a width of 30 mm was used.

From the result of the structural analysis using the finite element method shown in FIG. 6, as in the previous embodiment, as a result of restraining the torsion by the reinforcing plate 6 of the arm-shaped bed, the torsion in the arm 3 was obtained. Has also been significantly reduced, and the reduction in the swing of the upper part of the tower 4 has been significantly improved.

The reinforcing plate need only be provided at one of the corner of the bed and the tower and the base of the arm-shaped bed. It can be selected according to the shape of the sewing machine frame (length of the arm or the shape of the bed) and the structure of the mechanism such as drive and control. The reinforcing plate may be provided at both the corner of the bed and the tower and at the base of the arm-shaped bed.

The material of the reinforcing plate is rigidity (Young's modulus)
Any material may be used as long as it is high, and a non-ferrous metal material such as a steel material or aluminum may be used. Further, a fiber reinforced synthetic resin (FRP) in which fibers having a high Young's modulus, for example, carbon fibers or the like are compounded, can be used. The size of the reinforcing plate is preferably changed depending on the material of the reinforcing plate, the shape of the sewing machine frame, and the structure of mechanisms such as driving and control. Normally, the reinforcing plate has a thickness of 1 to 3 mm and a width of 10 mm
To 30 mm is preferred.

[0026]

EXAMPLE A sewing machine frame having the same shape as that of the embodiment was molded with BMC (Bulk Mold Compound: a material obtained by reinforcing a thermosetting resin with glass fibers). As shown in FIG. 3, the bed reinforcing plate was provided at both the corner of the bed and the tower and at the base of the arm-shaped bed. Reinforcement plate is thickness 2
The width of the reinforcing plate 5 at the corner between the bed and the tower was 30 mm, and the width of the reinforcing plate 6 at the base of the arm-shaped bed was 15 mm. In order to fix these reinforcing members, bosses for screw holes were previously formed on the bed of the sewing machine frame at the fixing positions of the reinforcing members.

Next, mechanisms such as drive and control are incorporated inside the sewing machine frame, and then the upper and lower portions of the open surface of the bed are connected to the bed side of the corner between the bed and the tower. A reinforcing plate was arranged and screwed. Similarly, a reinforcing plate was arranged on the side of the base of the arm-shaped bed portion near the arm-shaped bed portion so as to connect the upper portion and the lower portion of the open surface of the arm-shaped bed portion, and was screwed. When a sewing operation was performed using a sewing machine frame incorporating mechanisms such as drive and control, a sewing operation as smooth as that of the conventional box-shaped sewing machine frame shown in FIG. 9 could be performed. Of course, the swinging phenomenon of the sewing machine frame during the sewing operation was as low as that of the conventional box-shaped sewing machine frame, and the vibration was small.

Although the reinforcing plate is fixed to the bed by screws in the embodiment, it may be fixed by another fixing method, for example, an adhesive. When there is a visual problem in design, a plate formed of the same BMC as the main body can be used. However, in this case, it is necessary to make the plate thickness such that rigidity can be secured.

Further, in the present embodiment and examples, a sewing machine frame having an arm-shaped bed portion formed above the installation surface of the sewing machine frame is used, but a bed as shown in FIG. 4 is provided on the installation surface of the sewing machine frame. The same reinforcing effect can be obtained with a sewing machine frame installed on the entire surface.

[0030]

As described above, the present invention uses a sewing machine frame in which a bed, an arm and a tower, each of which has an open side and a U-shaped cross section, are integrally formed of a synthetic resin. Thereby, the manufacturing cost of the sewing machine frame is reduced, and the assembly of the mechanisms for controlling and controlling the sewing operation is facilitated, so that the assembly cost can be significantly reduced. Furthermore, by providing a simple reinforcing plate at a specific location of the bed of the sewing machine frame, conventionally, it was thought that it was impossible to realize a sewing machine frame in which one side surface was opened and the cross section was formed in a U-shape. It can have the same degree of rigidity as the conventional box-shaped sewing machine frame, and enables a smooth sewing operation.

[Brief description of the drawings]

FIG. 1 is a diagram showing a sewing machine frame according to an embodiment of the present invention in which a reinforcing plate is fixed to a sewing machine frame having one side opened.

FIG. 2 is a view showing a sewing machine frame according to another embodiment of the present invention in which a reinforcing plate is fixed to a sewing machine frame having one side opened.

FIG. 3 is a view showing a sewing machine frame according to an embodiment of the present invention in which two reinforcing plates are fixed to a sewing machine frame having one open side.

FIG. 4 is a view showing a sewing machine frame of the present invention in which a reinforcing plate is fixed to a sewing machine frame whose one side is opened.

FIG. 5 is a diagram showing a structural analysis by a finite element method of the sewing machine frame according to the embodiment of the present invention when a reinforcing plate is provided.

FIG. 6 is a view showing a structural analysis by a finite element method of a sewing machine frame according to another embodiment of the present invention when a reinforcing plate is provided.

FIG. 7 is a diagram showing a structural analysis of a sewing machine frame with one side opened by a finite element method.

FIG. 8 is a view showing the movement of the sewing machine frame of the sewing machine having one open side when the sewing machine is in operation; FIG. 8A is an external view as viewed obliquely from above; FIG.

FIG. 9 is a view showing a conventional sewing machine frame, wherein FIG.
Is a diagram showing a side surface, and FIG. B is a diagram showing a XX cross section.

FIG. 10 is a diagram showing a sewing machine frame with one side surface opened, FIG. 10A is a diagram showing the side surface, and FIG. 10B is a diagram showing a YY cross section.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Sewing machine frame 2 Bed 3 Arm 4 Tower 5 Reinforcement plate 6 Reinforcement plate 7 Arm-shaped bed portion 8 Open surface of bed 9 Open surface of arm-shaped bed portion 10 Opening for storing mechanisms such as drive and control 11 Reinforcement member A bed Corner between the tower and the tower B Base of the arm-shaped bed C Tip of the arm D Baseline of needle movement

Claims (4)

[Claims] 1. A sewing machine frame in which a bed, an arm, and a tower each having an open side surface and a U-shaped cross section are integrally formed of a synthetic resin. A sewing machine frame excellent in assemblability and rigidity, in which a reinforcing plate connecting an upper part and a lower part of an open surface of a bed is fixedly provided. 2. The sewing machine frame according to claim 1, wherein an end of said bed has an arm-shaped bed portion formed above an installation surface of the sewing machine frame. 3. The reinforcing plate according to claim 2, wherein an upper part and a lower part of an open surface of the arm-shaped bed portion are connected to and fixed to a base portion of the arm-shaped bed portion on the side of the arm-shaped bed portion. A sewing machine frame with excellent assemblability and rigidity. 4. The assemblability according to claim 2, wherein a reinforcing plate for connecting an upper portion and a lower portion of the open surface of the arm-shaped bed portion is fixedly provided on the arm-shaped bed portion side of the base portion of the arm-shaped bed portion. And rigid sewing machine frame.