JPS6118860Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to a shaking prevention mechanism that prevents a sewing machine table from swinging back and forth due to motor shaking when starting and stopping a sewing machine.

[Prior art]

Conventionally, the means for attaching the motor to a sewing machine is
For example, there is one shown in FIG.

A motor base (hereinafter referred to as "base") 2 equipped with anti-vibration rubber 1a and 1b is connected to a motor 3.
One of the downwardly curved portions 2a of the base 2 is attached to a mounting arm 4a protruding diagonally from the upper center of the outer casing 4 of the base 2 with a bolt 5 fitted in a substantially horizontal direction, and is attached to the other downwardly curved portion 2b of the base 2. The threaded portion 6n of the square-shaped motor height adjustment screw 6, which is also fitted almost horizontally, is passed through the mounting portion 4b formed on the side of the outer casing opposite to the mounting arm 4a, and then the pair of tightening nuts are inserted. It is firmly fixed to the motor 3 by clamping and fixing it from both the upper and lower sides by means 7.

The base 2 has a mounting bolt 9 screwed onto a sewing machine table (hereinafter referred to as "table") 8.
, the nut 9n is connected via the vibration-proof rubbers 1a and 1b.
It is tightened and hung.

Note that 10 is a control box.

Next, the relative positional relationship between the sewing machine 11 and the motor 3 is shown in FIG.

Sewing machine pulley 12 fixed to the main shaft of sewing machine 11
and a motor pulley 13 fixed to the rotating shaft of the motor 3.
are connected by a V-belt 14, rotate in the direction of arrow a when a sewing machine start switch (not shown) is turned ON, and the sewing machine pulley 12 which receives power via the V-belt 14 rotates in the direction of arrow b. The sewing machine pulley 12 is positioned on a line tilted backward (leftward in Fig. 2) by θ degrees with respect to the motor pulley 13. The anti-vibration rubbers 1a and 1b (not shown) are shown as models.

With the configuration described above, when starting the sewing machine 11, as shown in FIG.
Due to the relative relationship with Si, tension C in the direction of arrow c is instantaneously generated on the lower V-belt 14, but the sewing machine pulley 12 is attached to the table 8 via the fixed sewing machine 11. Compared to this, the rigidity is greater than that of the motor pulley 13 via the vibration isolating rubbers 1a and 1b, so an attractive force E acts to draw the motor pulley 13, that is, the motor 3 diagonally forward and upward.

When the sewing machine 11 is stopped, as shown in the figure, due to the relative relationship between the dynamic inertia force Mi of the sewing machine pulley 12 and the reaction force H of stopping the motor pulley 13, the upper V-belt 14u is caused to move in the direction of the arrow d. Since the tension D is generated for a very short time, a diagonally forward and upward attractive force F acts on the motor 3 in the same way as described above.
That is, when starting and stopping the sewing machine, attractive forces E and F are generated that try to pull the motor 3 diagonally forward and upwardly toward the sewing machine 11 and, by extension, the table 8, although their magnitudes are different. These attractive forces E and F are vertical component forces that push up the table 8, respectively.
Ecosθ and Fcosθ, and horizontal molecules Esinθ and Fsin that try to move table 8 forward
It is divided into θ, but the vertical molecule Ecosθ,
Most of Fcosθ is absorbed by the anti-vibration rubbers 1a and 1b, so its influence on the table 8 is extremely small, but the horizontal component forces Esinθ and Fsinθ
Even if some of the vibration is absorbed by the vibration isolating rubbers 1a and 1b, most of it has a large effect on the table 8, causing it to swing back and forth.

FIG. 4 is a side view showing a normal sewing work position.

Now, in the sewing work, when the sewing machine is first started, the above-mentioned attractive force E causes the sewing machine to
Although the anti-vibration rubbers 1a and 1b are deformed, they absorb the vertical component force Ecosθ by shrinking themselves, and receive the horizontal component force Esinθ to move the motor 3 forward. However, the motor 3 starts rotating and the gravitational force E
When the motor 3 weakens, the motor 3 automatically tries to return to the original position N, but due to the reaction from the forward and upward movement, the motor 3 goes too far backward. Then, as time passes, the motor 3 has a damped free vibration S as shown in FIG.
While doing so, it settles into a dynamic stable position M that is shifted from the original position N by a distance δ toward the sewing machine 11 side, and continues rotating.
On the other hand, when the sewing machine stops, it operates in almost the same way, and when the motor 3 stops, it moves from the dynamic stable position M to the home position N while performing damped free vibration as shown in the figure.
to return to.

Usually, the mass of the sewing machine 11 and the table 8,
The mass and rigidity of the legs 15 are not sufficient to resist the free vibrations of the motor 3, and the free vibrations are transmitted to the table 8 and generate vibrations, and the frequency is
Hz, and the amplitude is 1 mmp-p, which is further amplified during inching and back-tracking. Therefore, sewing worker W feels this vibration as "shaking",
In particular, the horizontal back-and-forth rocking shown by arrow g in Figure 4 not only gives a visual and tactile discomfort similar to seasickness, but also makes it psychologically uncomfortable, causing the needle drop to go awry, etc. This was also a cause of deterioration in the quality of sewn products.

[Purpose of invention]

The present invention was developed in view of the above-mentioned problems, and has a structure in which a support member is fixed to either the sewing machine table or the motor base and abuts on the other to suppress the free vibration of the motor. , aimed at solving these problems.

[Example of idea]

An embodiment of the present invention will be described below with reference to FIG.

First, to describe the configuration, the motor base (hereinafter referred to as the "base") 20 is a modified product of the base 2, and one of the downwardly curved parts is formed outward between the anti-vibration rubbers 1a and 1b installed in opposition to each other. A height adjustment bolt 21 with a threaded hole 20n threaded at a required location near the base of the portion 20a and a locking nut 21n fitted in advance.
After screwing into the screw hole 20n, screw it back until the head 21t of the bolt 21 comes into contact with the back surface 8b of the table 8, and at that position, tighten the locking nut 21n against the surface of the base 20. The bolt 21 is positioned and used as a supporting member.

Next, to describe the operation, when starting the sewing machine 11,
Or, when stopping, even if the motor 3 attempts to move upward due to the attractive force E or F that acts diagonally forward and upward due to the tension C or D generated in the V-belt 14, the head 21t of the height adjustment bolt 21 will not move. Since the base 20, that is, the motor 3 coupled to the base 20, is not displaced because it is stopped by the back surface 8b of the table 8, no vibration is generated.

However, while the motor 3 is in continuous operation, even if the motor 3 is vertically displaced around the point 8c where the head 21t of the bolt 21 contacts the back surface 8b of the table 8 as a fulcrum, the vibration is prevented. Since the vibrations are absorbed by the rubbers 1a and 1b, the effect on the table 8 is minimal.

In addition, as another embodiment, a screw hole 20m may be threaded at a key point near the root of the other curved portion 20b of the base 20, and the height adjustment bolt 21 may be screwed into the screw hole 20m. , furthermore, both screw holes 20
The two bolts 21, 21 may be used for the distances n and 20 m. Further, a screw hole (not shown) into which the height adjustment bolt 21 is screwed is formed on the back surface 8b of the table 8 at a location opposite to the screw holes 20n and 20m, and the height adjustment bolt 21 is used by standing upside down. You can.

Furthermore, the support member is not limited to the height adjustment bolt 21 as long as it is interposed between the base 20 and the table 8 and can prevent the table 8 from shaking.

[Effect of idea]

As explained above, the present invention has a small support member interposed between the sewing machine table and the motor base at an intermediate position between the opposing vibration isolating rubbers.
The structure prevents the motor from shifting when the sewing machine is started or stopped, so it is possible to prevent the motor from shaking when the sewing machine is started or stopped without compromising the anti-vibration effect of table vibration when the motor is idling.
Since we were able to significantly reduce the shaking that occurs in the front and rear directions of the table, it not only eliminates the discomfort experienced by sewing workers caused by the shaking of the table, but also prevents the quality of sewn products from decreasing due to needle drops. It has the effect of preventing

[Brief explanation of the drawing]

Fig. 1 is a diagram showing a mechanism related to the connection between a motor and a table of a conventional sewing machine; Fig. 1 is a plan view of the motor base; , Fig. 3 is an explanatory side view showing the relative positional relationship between the sewing machine and the motor, and Fig. 3 is an explanatory drawing of the tension acting on the V-belt. Figure 4 is an explanatory side view showing the sewing work position, Figure 5 is an explanatory side view showing the state of deformation of the anti-vibration rubber at the moment the motor starts or stops, and Figure 6 shows the free damping after the motor starts and stops. This is an explanatory diagram showing the transition of vibration over time. The figure is a diagram at startup, the figure is a diagram at stop, and Figure 7 is a diagram showing an embodiment of the present invention. The figure is a plane view of the motor base. The figures are side views of the motor and table in a coupled state. 1a... Anti-vibration rubber, 1b... Anti-vibration rubber, 2...
Motor base, 8... Sewing machine table, 21...
Height adjustment bolt, 21n...rotating nut.

Claims (1)

[Scope of Claim for Utility Model Registration] In a sewing machine in which the axis of rotation of the motor is located behind the axis of rotation of the main shaft of the sewing machine, the two are placed above and below a table, and both are connected by an endless belt, the motors are fixed at the bottom and separated from each other. It is equipped with a motor base that is fixed with bolts in contact with the underside of the table via anti-vibration rubber at multiple locations, and a plurality of supporting members that are fixed at one end to one of the table or the motor and the opposite end is engaged to the other. A swing prevention mechanism for a sewing machine table motor, characterized in that members are spaced apart from each other in at least the front-back direction to prevent back-and-forth vibration of a motor base.