JPH0350867Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Purpose of the Invention] (Field of Industrial Application) The present invention relates to a needle bar swinging mechanism for a horizontal gag-zag sewing machine, and is used, for example, in a household sewing machine.

(Prior Art) In the needle bar swinging mechanism of a conventional horizontal gag-zag sewing machine, for example, the one disclosed in Utility Model Publication No. 53-28620, the upper end of the needle bar support frame that holds the needle bar has an elastic plate. It is attached to a part of the arm through the handle, and is designed to swing along a kind of conical surface.This allows the rotating direction of the tip of the horizontal hook to be matched with the rotating direction of the needle. It is becoming more and more consistent.

(Problem to be solved by the invention) However, in such a needle bar swinging mechanism, when the needle enters a relatively thick sewing material, it encounters strong resistance, and the reaction force is applied to the needle bar and the needle bar. It is transmitted to the elastic plate via the support frame. Then, the elastic plate may deform, and the center of swing of the needle bar support frame may shift. In other words, when the center of oscillation moves toward the front, the gap between the needle tip and the horizontal hook tip opens slightly, causing skipped stitches.
There were problems such as when the center of oscillation shifted to the front and back, the needle tip collided with the horizontal gutter tip and broke the needle.

Therefore, the technical problem of the present invention is to prevent the pivot center of the needle bar support frame or the needle bar arm from shifting.

[Structure of the idea]

(Means for Solving the Problems) The technical means taken in the present invention to solve the above-mentioned technical problems are as follows: An arm and a semicircular spherical convex attached to the arm so as to protrude horizontally from the arm. a needle bar arm that has a recess on its upper side surface that slides on the semicircular spherical convex part and holds the needle bar so as to be movable up and down, and one end of which is disposed on the arm and the other end of which is connected to the recess of the needle bar arm. and a leaf spring that urges the semicircular spherical convex portion.

(Function) Therefore, when the needle pierces thick fabric,
Even if the reaction force of the resistance received from the cloth is transmitted to the hole that is the center of swing of the needle bar and the semicircular spherical protrusion, the semicircular spherical protrusion slides against the concave part and the reaction force is absorbed. , the center of oscillation is not displaced. Therefore, the various problems described above due to the shift of the center of oscillation will not occur.

(Example) Hereinafter, an example embodying the technical means of the present invention will be described based on FIGS. 1 to 5.
1 and 2, a side surface 12a of a jaw portion 12, which is the terminal end of an arm 11 of a sewing machine 10, is open, and the opening is closed by a face plate (not shown). The needle bar 14 protrudes from within the jaw portion 12 in the direction of the bed 13 facing the jaw portion 12. The needle bar arm 15 has an upwardly protruding portion 15a.
and bushes 16, 16 on the downward protrusion 15b.
(Only one side is shown) It is mounted so that it can move up and down or go up and down. A needle bar 17 is attached to the lower end of the needle bar 14 in a well-known manner, and the needle 17 performs sewing as the needle bar 14 engages with a crank lock (not shown) and moves up and down.

A pin 18 is installed in the needle bar arm 15 so as to be relatively rotatable between its upper protrusion 15a and lower protrusion 15b. The pin 18 is also inserted into the free end 19a of the extender rod 19, and is secured to the free end 19a of the extender rod 19 by means of a screw 20.
is fixed. However, the width rod 19
As is well known, the sewing machine is operatively connected to a pattern generating mechanism (not shown), and when the sewing machine is driven, it makes reciprocating horizontal movements in the X-X direction, that is, in the direction orthogonal to the raphe line. ing. In addition, 21 is an E-ring, and the pin 18 and the free end 19a of the extension rod 19
It is designed to absorb the looseness between the two.

The upper end portion 15c of the needle bar arm 15 has a conical convex portion 15d and a hemispherical concave portion 1 on the front and rear surfaces, respectively.
5e is formed. The conical recess 15e is mounted so as to be rotatable in all directions on a semicircular protrusion 24 provided on one side of the support plate 23 by the biasing force of the free end 22a of the leaf spring 22. Thus, the base end 22b of the leaf spring 22 is fixed to the other side of the support plate 23 with a screw 25, and the support plate 23 is
The screw 2 is inserted into a hole 27 formed in a protrusion 26 protruding from the upper end surface of the jaw portion 12 of the arm 11.
8 is integrally fitted and fixed to a support shaft 29 fixed to the protrusion 26.

Further, a plate 31 in which an arc-shaped elongated hole 30 is formed is fixed to the lower surface 12b of the jaw portion 12 by two screws 32, and the bush 16 passes through the elongated hole 30. The reference numeral 33 denotes a horizontal spool disposed below the bed 13 and rotated by a shaft 34, and is provided with a race surface 35 and a tip 36.

Note that the R center of the elongated hole 30 is on a line connecting the swing center C of the needle bar arm 15 and the intersection of the axial center of the hook shaft 34 and the race surface 35.

The operation of the above configuration will be described. When the sewing machine is driven, the needle bar 14 reciprocates in the vertical direction, and the widening rod 19 reciprocates in the horizontal direction so as to be orthogonal to the sewing line. As a result, the needle bar arm 15 is forced to move in a similar manner due to the horizontal reciprocation of the width adjustment rod 19, but the bush 16, which is integrated with the needle bar arm 15 and holds the needle bar 14,
Since the bush 16 can only move along the elongated hole 30, the bush 16 can reciprocate in the Y-Y direction (FIG. 4). Furthermore, the needle bar arm 15 swings in the ZZ direction due to relative displacement or sliding of the upper end portion 15c of the needle bar arm 15 with respect to the semicircular spherical convex portion 24 (FIG. 2). Thus, the needle bar 14 held by the needle bar arm 15 and the needle 17 integrated with the needle bar 14
is a combination of the above-mentioned reciprocating motion in the YY direction and reciprocating motion in the ZZ direction, and rotates around the CD line and reciprocates so as to draw a conical surface. Therefore, as shown in FIG. 6, it swings in the W-W direction to match the rotating direction of the tip 36 of the horizontal hook 33, and to maintain a constant gap between the needle 17 and the tip 36. I can do it.

[Effect of idea]

In order to solve the above-mentioned technical problem, it is possible to increase the strength of the elastic plate, but if the strength is increased too much, the driving force for swinging the needle bar support frame will have to be increased. Become. but,
In this invention, since the configuration is as described above,
There is no need to increase the force driving the needle bar arm compared to before.

In addition, even when the needle bar and needle bar arm receive strong resistance from the sewing machine needle, such as when sewing thick sewing items, the needle bar arm absorbs the reaction force of this resistance upward against the semicircular convex part. Absorb by sliding. Therefore, no excessive load is applied to the needle bar and the needle bar arm, and the needle bar and the needle bar arm do not bend. Further, even if a strong resistance force is applied, the center of swing will not be displaced from the center of the semicircular spherical convex portion, making it possible to continue stable sewing work.

Furthermore, in the present invention, even if wear occurs in the concave portion or semicircular convex portion of the needle bar arm, the needle bar arm is always urged toward the semicircular convex portion by the leaf spring, so that play is prevented. It never happens.

[Brief explanation of drawings]

Fig. 1 is a front view of the needle bar swinging mechanism of the horizontal gag-zag sewing machine according to the present invention, Fig. 2 is a side view of the device shown in Fig. 1, Fig. 3 is a sectional view taken along the line of Fig. The figure is an explanatory diagram of a plate that restricts the movement of the needle bar, and FIG. 5 is a diagram showing the relationship between the tip of the needle and the needle drop. 11... Arm, 14... Needle bar, 15... Needle bar arm, 15e... Semicircular spherical recess (recess), 22...
Leaf spring, 24... semicircular spherical convex part.

Claims (1)

[Scope of utility model registration request] a needle bar arm that holds the needle bar so as to be movable up and down; an arm, a semicircular spherical convex portion attached to the arm so as to project horizontally from the arm, and a concave portion that slides on the semicircular spherical convex portion on the upper side surface; and a plate spring having one end disposed on the arm and the other end biasing the concave portion of the needle bar arm toward the semicircular spherical convex portion. Rocking mechanism.