JP3617191B2 - Sewing frame drive device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a feed frame driving device for a sewing machine.
[0002]
[Prior art]
In a conventional feed frame drive device with a feed frame, a feed frame holding a sewing product is taken via a drive arm against a feed base that moves in a plane that intersects the reciprocating direction of the needle. I wear it. The mounting connection position between the drive arm and the feed frame for driving the feed frame is uniquely determined by considerations such as ease of assembly, and the consideration for the center of gravity position of the feed frame is Was not.
[0003]
[Problems to be solved by the invention]
Therefore, if there is a difference between the mounting position (connecting position) of the drive arm in the height direction and the center of gravity position of the feed frame in the height direction, a couple of forces will be generated in addition to the inertial force due to the reciprocation of the feed frame. The feeding frame vibrates due to the couple, which is a problem. That is, the feed frame is prepared according to the size, shape, etc. of various sewing products, and in some cases, an auxiliary device for holding the sewing product may be provided on the feed frame. For this reason, the center-of-gravity position may change for each feed frame. For this reason, the aforementioned couple is generated. For example, when the position of the center of gravity differs in the height direction, the feed frame flutters in the vertical direction due to the couple generated thereby, resulting in problems such as noise and deterioration of the quality of the sewing product.
[0004]
The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a feed frame drive device for a low-vibration sewing machine so that no couple is generated when the feed frame reciprocates. That is.
[0005]
[Means for Solving the Problems]
In order to achieve this object, the feed frame driving device of the sewing machine according to claim 1 is capable of changing the connection position between the feed frame and the drive arm in response to a change in the center of gravity of the feed frame. It is characterized by. By changing the coupling position, the vibration of the feed frame can be reduced.
[0006]
According to a second aspect of the present invention, there is provided a feed frame drive device for a sewing machine in which a couple of forces generated by a difference between an inertial force due to a reciprocating motion of the feed frame and a distance between a gravity center position of the feed frame and a connection position of the drive arm is substantially zero. Therefore, it is possible to prevent the feed frame from vibrating.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0008]
FIG. 1 is an overall view of the feeding mechanism. As is well known, a sewing machine having a feed frame is a feed frame that is moved back and forth and right and left in a direction perpendicular to the up and down reciprocating direction of the needle N on the sewing table P and the needle N that carries the needle thread and moves up and down. 3.
[0009]
A device for driving the feed frame will be described. As shown in FIG. 1, a feed frame 3 is set on the upper surface of a sewing table (only a part thereof) P so as to be reciprocally movable in a horizontal plane by an X direction moving mechanism and a Y direction moving mechanism. A sewing product (not shown) is fixed. Here, the XY moving mechanism will be described with reference to FIGS.
[0010]
The X direction moving mechanism is provided on a Y frame 21 reciprocally moved in the Y direction, and includes a drive source 11, a driving force transmission mechanism 13, an X frame 15, and an X guide 19, and the X frame 15 includes the feed frame. 3 is fixed by the method described later. When the drive source 11 operates in the direction of the arrow in FIG. 5, the X frame 15 can move only in the X direction along the X guide rail 23 installed on the Y frame 21.
[0011]
On the other hand, the Y-direction moving mechanism includes a driving source 25, a driving force transmission mechanism 27, a Y frame 21, an X guide rail 23, a fixed guide rail 29, a Y driving arm 31, and a Y guide 33. One of the Y drive arms 31 is fixed to the Y frame 21 and the other is fixed to the Y guide 33. When the drive source 25 operates in the direction of the arrow in FIG. 6, the Y frame 21 can move only in the Y direction along the fixed guide rail 29.
[0012]
By combining the X direction moving mechanism and the Y direction moving mechanism described above, the feed frame 3 can be moved to an arbitrary point in the XY plane.
[0013]
Next, a method for fixing the Y drive arm 31 as the drive arm of the present invention to the Y frame 21 and the Y guide 33 will be described with reference to FIGS. An upright portion 21a is formed on one side of the Y frame 21, and two female screws 21b for attaching the Y drive arm 31 are arranged in a row in the upright portion 21a. The Y drive arm 31 is formed in a U shape, and a through hole corresponding to the female screw 21b is provided in one arm portion 31a, and both are detachably fastened by a screw. The fastening with the Y guide 33 is also performed with the same configuration. That is, a pair of through holes 31d are formed in the other arm portion 31c facing the one arm portion 31a, and the Y guide 33 is detachably fastened by screws through the through holes 31d.
[0014]
The Y drive arm 31 having this configuration is used as a first drive arm, and the Y drive 31 is configured such that the Y frame 31 is in a state where the connecting arm portion 31e for connecting the pair of arm portions 31a and 31c is positioned below as shown in FIG. 21 and the Y guide 33 are connected to each other, and as shown in FIG. 3, the Y frame 21 and the Y guide 33 are connected to each other with the connecting arm portion 31e connecting the pair of arm portions 31a and 31c positioned above. It is possible to take two connection modes of connecting the two.
[0015]
On the other hand, as the Y drive arm 31, a second drive arm having a different form from the first drive arm is prepared. The second driving arm has a shape in which the connecting arm portion 31e of the first driving arm connects the pair of arm portions 31a and 31c at an intermediate position in the height direction.
[0016]
Since the feed frame 3 is held on the Y frame 21, the Y frame 21 and the feed frame 3 are connected to each other due to the presence of a sewing object and an auxiliary presser provided on the feed frame for supporting the work piece. The center of gravity position in the height direction when integrated is changed. For convenience of explanation, this barycentric position is referred to as the barycentric position of the Y frame 21.
[0017]
However, the force point of the driving force from the Y guide 33 can be changed in the vertical direction by changing the mounting direction of the first driving arm as the Y driving arm 31 or using the second driving arm. . That is, when the center of gravity of the Y frame 21 is point G, as shown in FIG. 2, the first drive arm is used as the Y drive arm 31, and the connecting arm portion 31e is positioned below the Y frame 21. By connecting the Y guide 33 and the Y guide 33, the position of the center of gravity of the Y frame 21 and the point of action of the feed force by the Y guide 33 substantially coincide with each other, and no vibration is generated in the feed frame 3.
[0018]
When the center of gravity of the Y frame 21 is at point G ′, as shown in FIG. 3, the first drive arm is used as the Y drive arm 31 and the connecting arm portion 31e is positioned on the Y frame. 21 and the Y guide 33 are connected to each other so that the position in the height direction of the center of gravity of the Y frame 21 and the point of action of the feed force by the Y guide 33 substantially coincide with each other, and no vibration is generated in the feed frame 3.
[0019]
Further, when the center of gravity of the Y frame 21 is at the point G ″, as shown in FIG. 4, if the second drive arm is used as the Y drive arm 31, the center of gravity of the Y frame 21 and the action of the feed force by the Y guide 33 The position in the height direction substantially coincides with the point, and no vibration occurs in the feed frame 3.
[0020]
It should be noted that the change in the center of gravity position due to the difference in the workpiece can be easily known in advance by analysis or the like, and the connection position may be determined based on this result.
[0021]
Next, the action of force during sewing will be described with reference to FIG. FIG. 7 is a simplified side view of a conventional feed frame drive mechanism, in which the article to be sewn, the feed frame 3, the X-direction moving mechanism, and the Y frame 21 are represented as one driven body 35.
[0022]
When the driving source 25 operates in the direction of the arrow r in FIG. 7, the driven body 35 moves in the direction of the arrow d via the driving force transmission mechanism 27. At this time, if acceleration: a is generated in the driven body 35, an inertial force: F acts on the driven body 35. The inertial force F is expressed by F = m · a, where m is the weight of the driven body 35. Then, the gravity center position G in the height direction of the driven body 35 and the attachment position g between the Y drive arm 31 and the Y frame 21 and the Y guide 33 are not the same height. M = F · h acts on the driven body 35, and the Y driving arm 31 is deformed as indicated by a broken line. When the gravity center position G and the attachment position g are the same height, only the inertial force F acts, so that the above-described deformation does not occur.
[0023]
In addition, this invention is not limited to embodiment mentioned above, In the range which does not deviate from the meaning, a various change can be added. For example, although the connection fixing position has been changed in three ways, the number may be further increased or conversely decreased.
[0024]
Further, although the Y frame 21 is provided with a female screw, it may be oval shaped to further increase the degree of freedom in changing the fixing position.
[0025]
Similarly, the change of the connecting and fixing position may be made free with respect to the change of the center of gravity position in the horizontal direction.
[0026]
【The invention's effect】
As is apparent from the above description, according to the feed frame driving device of the sewing machine according to claim 1, the connection position between the feed frame and the drive arm can be changed in response to the change in the center of gravity of the feed frame. Therefore, the vibration of the feed frame can be reduced by changing the connection position.
[0027]
According to the feed frame driving device of the sewing machine according to claim 2, the couple force generated from the difference between the inertial force due to the reciprocating motion of the feed frame and the distance between the gravity center position of the feed frame and the connecting position of the drive arm is made substantially zero. Therefore, it is possible to prevent the feed frame from vibrating.
[Brief description of the drawings]
FIG. 1 is an overall schematic perspective view of a sewing machine feed mechanism according to an embodiment of the present invention.
FIG. 2 is a diagram illustrating a driving arm attachment state in the case of a center of gravity point G;
FIG. 3 is a diagram showing a driving arm attachment state in the case of a center of gravity point G ′.
FIG. 4 is a diagram showing a driving arm attachment state in the case of a center of gravity point G ″.
FIG. 5 is a top view showing a schematic configuration of an X-direction moving mechanism.
FIG. 6 is a top view showing a schematic configuration of a Y-direction moving mechanism.
FIG. 7 is an explanatory diagram of generation of couples.
[Explanation of symbols]
3 Feed frame 15 X frame 21 Y frame 31 Y drive arm 33 Y guide

Claims (2)

A needle that is reciprocated and a feed frame that is connected to a drive arm that is moved in a plane that intersects the reciprocating direction, and a predetermined seam is formed on the workpiece that is held by the feed frame. In the sewing machine that
A feed frame drive device for a sewing machine, wherein the connection position of the feed frame and the drive arm can be changed in response to a change in the center of gravity of the feed frame. 2. The sewing machine according to claim 1, wherein a couple generated by a difference between an inertial force caused by a reciprocating motion of the feed frame and a distance between a gravity center position of the feed frame and a connection position of the drive arm is set to be substantially zero. Feed frame drive device.

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