JPS5817591Y2 - Transmission mechanism in needle drive device of sewing machine - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a transmission mechanism in a needle drive device of a sewing machine.

In general, the transmission mechanism in this type of needle drive device includes an approximate linear movement mechanism that moves the connecting part between the needle holder and the swinging arm in an arc shape that approximates a straight line, and an approximate linear motion mechanism that moves the needle holder on a true straight line. There is a strictly straight line motion mechanism that allows

This idea belongs to the latter category. The approximate linear motion mechanism is determined by rigorous calculation of the composition ratio of each link that makes up the mechanism, and the error that occurs in the linear motion of the directly connected part between the needle holder and the swinging arm is determined by the ratio of each link that makes up the mechanism. Since the precision of each part is proportional to the precision of the parts, the precision of each part is required to be absolute, and as a result, the resulting mechanism is forced to be expensive.

On the other hand, in a strictly straight line motion mechanism, a needle holder fitted externally on a guide rod is placed at the tip of a sliding ring that is concentrically and slidably fitted into a swinging arm, at the center of the axis of the sliding shaft. There is a structure in which the guide rods are connected so that they are located on the extension line (for example, Japanese Patent Publication No. 5422/1983).

According to this, the guide rod, the connecting portion between the sliding shaft and the needle holder,
Even if the axes of the swinging arm are aligned in a straight line, the connecting part is between the guide rod and the swinging arm, so when the needle holder moves up and down, a bending moment acts on the guide rod, causing the guide Frictional resistance increases during sliding contact between the rod and the needle holder, and there is a risk of seizure due to heat generation during high-speed operation of the sewing machine.

In addition, wear occurs due to increased frictional resistance, which reduces durability, and errors occur in the vertical position of the needle, which may cause errors in the intersection point with the looper in edge sewing machines.

In the same strictly straight line movement mechanism, there is also a
In addition to opening holes in six directions: front and rear, left and right, and top and bottom,
Into the left and right holes, a horizontal shaft with cross-shaped holes in the front and back and up and down directions is inserted, and furthermore, a swinging arm with a hole in the vertical direction at the tip is inserted into the front and rear holes of the horizontal shaft, and the needle is held in place. There is a structure in which a guide rod is inserted into the horizontal shaft and the upper and lower holes of the swinging arm, and the needle holder is raised and lowered by the action of the swinging arm (for example, Japanese Patent Publication No. 49-5946).

However, according to this method, the structure of the needle holder is complicated, so it is expensive.Moreover, since the swing arm has upper and lower holes through which the guide rod is inserted, it is necessary to ensure strength. , the swinging arm is forced to become thicker, and furthermore,
Since a horizontal shaft and a needle holder are formed on the outside of the horizontal shaft, the overall size has to be increased.

Therefore, the overall weight increases and the kinetic inertia increases accordingly, resulting in a disadvantage that it is not suitable for high-speed operation.

In other strictly straight line motion mechanisms, there is a structure in which protrusions are provided on the left and right sides of the needle holder, and a long hole at the tip of the swinging arm is engaged with the protrusions like a pin joint (for example,
5946), but according to this, the swinging arm and needle holder are:
Since there is only a line contact and the contact is a sliding contact, there is a drawback that the friction of the contact portion is severe and durability is poor.

The purpose of this invention is to eliminate all of these drawbacks, and its purpose is to reduce the weight and inertia of movement by downsizing the needle holder and its surrounding parts. , the purpose of this invention is to provide a transmission mechanism that is suitable for high-speed operation, and the purpose of this invention is to make surface contact of the movement transmission part as uniform as possible, and to have high wear resistance, so that The purpose of this invention is to provide a transmission mechanism with no errors, and the purpose of this invention is to provide an inexpensive transmission mechanism that has a small number of parts and a simple shape, making manufacturing and assembly easy. .

That is, this invention, as in the illustrated embodiment, includes a vertical guide rod 2 protruding from a machine frame 1, and a needle holder 4 that is slidably fitted onto the guide rod 2 and has a needle 3 fixed thereto. and a swinging arm 7 which is pivotally connected to the pivot shaft 5 and is swingable about the pivot shaft 5 by the rotation of the rotating main shaft 6, and whose tip is connected to the needle holder 4. In a sewing machine configured to be raised and lowered vertically, a needle holder body 9 has a vertical hole 8 in which the needle 3 is fixed with the needle facing downward and the guide rod 2 is inserted through it and makes sliding contact with the needle holder body 9, and the upper part of the body 9 is integrated. An outer frame 11 having a continuous horizontal hole 10 with a circular cross section on the inside, and a gap 12 having a diameter such that it does not come into contact with the guide rod 2 during elevation.
and a horizontal shaft that is inserted into a horizontal hole 10 of the outer frame 11 and is configured to be rotatable in the circumferential direction of the horizontal hole 10, and further has a sliding hole 13 in a direction intersecting the horizontal hole 10. 14, and a swinging arm 7 having a distal end portion 15 that is slidably inserted in the sliding hole 13 of the horizontal shaft 14 in the axial direction, and the guide rod 2 and the horizontal shaft 14 are connected to each other. The center axis of the horizontal shaft 14 is perpendicular to the center axis of the guide rod 2, and the center axis of the front end 15 of the swing arm 7 is perpendicular to the horizontal axis. 14, so as to be perpendicular to the extension of the solid axis of
The present invention relates to a transmission mechanism in a needle drive device of a sewing machine, characterized in that the arrangement is connected.

Next, this invention will be explained based on the drawings of the embodiments.

A cylindrical guide rod 2 is provided to protrude downward from a machine frame 1 forming a part of a sewing machine body, and a needle holder 4 is externally fitted onto the guide rod 2.

The needle holder 4 fixes the needle 3 facing downward to the front part of the main body 9 with a bolt 3', and inserts the guide rod 2 into a vertical hole 8 formed approximately at the center of the needle holder main body 9. and is configured to be slidable in the axial direction of the guide rod 2.

Here, the needle 3 is fixed to the needle holder 4 on the left side of the guide rod 2 in FIG. 1, but the needle 3 is not limited to this position, for example, in front of the guide rod in FIG. It may be fixed to the needle holder at the rear.

The upper part of the main body 9 is integrally provided with an outer frame 11 having a horizontal hole 10 with a circular cross section inside, and the top of the outer frame 11, which is an extension of the vertical hole 8, also has a hole 11 through which the guide rod 2 is inserted. will be established.

A horizontal shaft 14 is inserted into the horizontal hole 10 and slidably contacts the inner wall of the horizontal hole 10 in the circumferential direction.

The horizontal shaft 14 has a circular gap 12 with a diameter larger than that of the guide rod 2.
Open vertically.

The diameter of the gap 12 may be such that the horizontal shaft 14 and the guide rod 2 do not come into contact even if the horizontal shaft 14 rotates in the circumferential direction due to the swinging of the swinging arm 7, which will be described later.

Furthermore, a sliding hole 13 is provided in the horizontal shaft 14 in a direction that intersects with the horizontal hole 10 on the side of the gap 12 .

A distal end portion 15 of a swinging arm 7, which swings about a pivot 5 by a rotating main shaft 6, is inserted into the sliding hole 13 so as to be slidable in the axial direction thereof.

Thus, the guide rod 2, the horizontal shaft 14, and the tip 15 of the swinging arm 7 are such that the central axis of the horizontal shaft 14 is orthogonal to the center axis of the guide rod 2, and the tip 15 of the swinging arm 7 such that the central axis of is orthogonal to the extension of the central axis of the horizontal axis 14,
Placement will be communicated.

Therefore, no bending moment in the axial direction of the swinging arm 7 is applied to the guide rod 2, making it easy to regulate the needle drop position, improving the durability of the needle drive mechanism and the smoothness of its operation. do.

The swinging arm 7 is fastened to a pivot shaft 5 that rotates in the circumferential direction by a bolt 16, and the pivot shaft 5 is connected to the pivot shaft 5 via a ball crank 17 of the main shaft 6, a rod 18, a ball joint 19, and an arm 20. You will be contacted.

A collar 21 and a bolt 22 are fixed to the horizontal shaft 14 for abutting against the end surface of the outer frame 11 and locking the horizontal shaft 14 in the horizontal hole 10 of the outer frame 11.

Thus, when the swinging arm 7 swings up and down by the rotating main shaft 6,
Along with this, the needle holder 4 is guided by the guide rod 2 and moves up and down.

Since the swinging arm 7 rotates around the pivot 5, its tip 15 moves up and down in an arc, but the tip 15 inside the sliding hole 13 moves up and down.
By sliding, the needle holder 4 moves up and down smoothly.

At this time, the change in angle due to the rotation of the swinging arm 7 appears as a change in the rotation angle of the horizontal shaft 140, and the horizontal shaft 14 rotates in the circumferential direction within the horizontal hole 10 of the needle holder 4. do.

Thus, the needle holder 4 moves up and down linearly, and the needle 3 also moves up and down accordingly.

As is clear from the above, according to this invention, since the structure of each member constituting the needle holder is not complicated, each member can be downsized, and the connection between the horizontal shaft and the swinging arm is Since the tip of the swinging arm is simply slidably inserted into the sliding hole, the swinging arm can also be configured to be thin.

Therefore, the weight of the needle holder and the members near it can be reduced.

As a result, the kinetic inertia during the ascent and descent is significantly reduced, thereby making it possible to obtain a transmission mechanism that is suitable for high-speed operation.

In addition, since the horizontal shaft, the guide rod, and the tip of the swinging arm are arranged and communicated as described above, there is no bending moment in the axial direction of the tip of the swinging arm caused by the swinging of the swinging arm.
Bending moments in other directions are not concentrated at one point, and furthermore, since all motion transmitting parts are in surface contact, frictional resistance is not concentrated at one point.

Therefore, there is no risk of partial breakage or wear, and not only is the needle's upward and downward locus less likely to be distorted, but also a robust transmission mechanism can be obtained.

Further, according to this invention, since the number of parts is small and the structure is simple, manufacturing and assembly is easy and an inexpensive transmission mechanism can be obtained.

[Brief explanation of drawings]

The drawings show one embodiment of this invention, in which Fig. 1 is a schematic front view with a part cut away, Fig. 2 is a plan view with the section A-A in Fig. 1 cut away, and Fig. 3 is a partially cutaway front view. 1 is a sectional view taken along the line B-B in FIG. 1. In the diagram, 1 is the machine frame, 2 is the guide rod, 3 is the needle, 4 is the needle holder, 5
is a pivot, 6 is a rotating main shaft, 7 is a swing arm, 8 is a vertical hole, 9 is a needle holder body, 10 is a horizontal hole, 11 is an outer frame, 12 is a gap, 13
14 is a sliding hole, 14 is a horizontal shaft, and 15 is a tip of a swinging arm.

Claims (1)

[Scope of utility model registration request] A vertical guide rod protruding from the machine frame, a needle holder that is slidably fitted onto the guide rod and has a needle fixed to it, and a needle holder that is pivotally attached to a pivot shaft and can swing freely around the pivot shaft by the rotation of the rotating main shaft. In a sewing machine configured to have a swinging arm whose tip is connected to the needle holder, and configured to raise and lower the needle holder linearly, the needle is fixed facing downward and a guide rod is inserted through the sewing machine. A needle holder main body has a vertical hole that slides into contact with the needle holder, an outer frame that is integrally continuous with the upper part of the main body and has a horizontal hole with a circular cross section on the inside, and a gap with a diameter that does not contact the guide rod during elevation. and a horizontal shaft that is inserted into a horizontal hole of the outer frame and is rotatable in the circumferential direction of the horizontal hole, and further includes a horizontal shaft having a sliding hole in a direction intersecting the horizontal hole, and a sliding shaft of the horizontal shaft. a swinging arm having a distal end that is slidably inserted into the movable hole in the axial direction, and the guide rod, the horizontal shaft, and the distal end of the swinging arm are connected to characterized in that the central axis is orthogonal to the central axis of the guide rod, and the central axis of the tip of the swinging arm is orthogonal to the extension of the central axis of the horizontal shaft; A transmission mechanism in a needle drive device of a sewing machine.