JPH0262275B2 - - Google Patents

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) The present invention relates to a needle bar arm fixing device for a sewing machine, which simplifies thread replacement operations in sewing operations that require thread replacement. Therefore, it is used in a multi-needle sewing machine in which a needle bar arm having a large number of needle bars is moved to selectively place only a desired needle bar at a sewing position.

(Prior Art) Conventionally, as this type of device, the following technologies shown in FIGS. 6 to 8 are known. (Japanese Patent Publication No. 59-49796).

In the figure, 31 is a switching dial located on the front surface of the horizontal longitudinal body 30 of the arm, and is fixed to a switching shaft 32 that is loosely fitted to the longitudinal body 30. This switching shaft 32 has a switching fork 33 at its center, and a positioning arm 35 at its rear end via a positioning plate 34.
is fixed. A needle bar arm (not shown) that holds a plurality of needle bars is fixed to the end (left side in FIG. 7) of the needle bar arm shaft 36 that is orthogonal to the switching shaft 32.

As seen in FIG. 7, the needle bar arm shaft 36 has
R portion 33a formed at the end of the switching fork 33
, washers 37, 37', elastic bodies 38, 38',
It is sandwiched from both sides by collars 39, 39', etc., respectively.

As seen in FIG. 8, pins 40 and 41 are fixed to the positioning arm 35, and long holes 34a and 34b for locking the pins 40 and 41 are formed in the positioning plate 34 fixed to the arm body 30. It is provided.

When switching the sewing needle bar, operate as follows.

That is, the switching dial 31 is pressed to disengage the pins 40, 41 of the positioning arm 35 from the elongated holes 34a, 34b of the positioning plate 34. Then, move the switch dial 31 so that the desired needle bar is at the sewing position.
is pressed and turned to slide the needle bar arm shaft 36 through the switching fork 33. (The needle bar arm, not shown, is also in synchronization.) The movement of the needle bar arm is regulated by a stopper, not shown.
Turn against 38'. Then, when the pressing is released while maintaining the rotational position of the switching dial 31,
The pins 40, 41 engage with either the elongated holes 34a, 34b. At the same time, due to the restoration of the elastic body,
The switching shaft 32 moves slightly by the amount of restoration, and the pin comes into contact with the long hole in one direction. This fixes the position of the needle bar arm without any play.

(Problem to be Solved by the Invention) In the needle bar switching in the above technology, even if the switching dial is turned against the elastic body and the switching dial operation is released, even if the pin and the slotted hole come into contact, If the elasticity of the body is not in its active state, the needle bar arm side will wobble. This required a relatively large amount of control maintenance force to operate the switching dial, which added to the burden on the female worker to some extent. The present invention aims to eliminate these drawbacks and ensure light and stable workability.

[Structure of the invention]

(Means for Solving the Problems) In the present invention, the above problems are solved by the following configuration means. That is, as shown in FIG.
Stopper plates 5, 6 are engaged with the end face of the shaft portion 3a and the end face of the collar 4, and are fixed to the needle bar arm 3, and stoppers 7, 8 are adjustable and fixed within the machine frame.
The needle bar arm is fixed by engagement between the recess 9a provided in the positioning arm 9 and the pins 11 and 12 fixed to the positioning plate 10.

(Function) The needle bar arm is fixed by the stoppers 7 and 8, the stopper plates 5 and 6, one side of the recess 9a of the positioning arm 9, and the side of the pins 11 and 12.

The engagement between the pin and the positioning arm can be released with a light operating force sufficient to eliminate the frictional resistance between the side surface of the pin and the side surface of the positioning arm recess.

(Embodiment) Reference numeral 13 shown in FIG. 1 is a push-down arm, and a push-down shaft 14 is rotatably supported on the push-down arm by a machine frame (not shown). The push-down arm 13 has recesses 1 of the needle bars 15, 15' shown in FIGS. 2 and 3.
5a, 15a' and a relief part 16
The push-down body 16 having b is fixed. An R-shaped push-down bar 19 having a plurality of needle bars at the same height is fixed to the push-down body 16. A solenoid 20 fixed to the machine frame is connected to the push-down arm 13.
3 to align the needle bars to the same height and pull the non-sewing needle bar upward.

A positioning arm 9 having a recess 9a is fixed to the push-down shaft 14, and swings in the same manner as the push-down arm 13. Stoppers 7, 8 that determine the position of the needle bar arm 3
is eccentrically adjustable and is adjustable and fixed to the machine frame. The needle bar arm 3 has its shaft portion 3a.
are slidably supported on the machine frame, and stopper plates 5 and 6 are fixed in contact with the stoppers 7 and 8 to determine the left and right positions of the needle bar arms. The outer end of the needle bar arm shaft portion 3a forms a stepped shaft 3b.

Among the needle bars held by the needle bar arm 3, the needle bar in the sewing position can slide on a needle bar guide shaft 21 (see FIG. 2) in which the rotation of the upper shaft (not shown) is changed into vertical movement. Connected to the supported crank rod end 22,
The convex portion 22a engages with the concave portions 15b, 15b' of the needle bar to transmit vertical movement to the needle bar.

In addition, the non-sewing needle bar is connected to the projection 16 of the push-down body 16.
a engages with the recesses 15a, 15a', and the protrusion 22a of the crank rod end disengages with the recesses 15b, 15b', causing it to be pulled upward.

A switching arm 2 having an R-shaped end 2a is fixed to a switching shaft 1 which is orthogonal to the needle bar arm shafts 3a and 3b and loosely fitted into the machine frame. The tip R-shaped portion 2a of this switching arm 2 has a stepped portion 3b as described in the configuration section above.
and a collar 4, so that the swinging movement of the switching arm 2 is linked to the sliding movement of the needle bar arm 3 in a conversion manner.
Note that the collar 4 is fixed to the step portion 3b.

A solenoid 23 is fixed to the machine frame, and is connected to the switching arm 2 with a rod 24 and a step screw 25. A positioning plate 10 is fixed to the end of the switching shaft 1, and pins 11 and 12 that engage with the recess 9a of the positioning arm 9 are fixed.

Next, the operation of the embodiment of the present invention will be explained.

In FIG. 1, the right needle bar 15 is in the sewing position. In this state, the stopper plate 5 and the stopper 7 are in contact with each other, and the left side surface of the left pin 12 fixed to the positioning plate 10 and the recess 9 of the positioning arm 9 are in contact with each other.
The needle bar arm 3 is fixed by contacting the left side surface of the needle bar a.

When switching the needle bar, first the solenoid 20 is sucked by operating a switch (not shown).

Then, the push-down arm 13 swings, and the non-sewing needle bar 15' is pushed down to the same height as the needle bar 15 in the sewing position. At this time, the positioning arm 9 also swings in the same manner as the push-down arm 13, and the engagement between the recess 9a and the pin 12 is released. After this operation is completed, the solenoid 23 acts, and the switching arm 2 and the positioning plate 10
swings counterclockwise. This counterclockwise rocking of the switching arm 2 causes the needle bar arm 3 to move to the right. Therefore, the stopper plate 6 and the stopper 8 come into contact with each other, and the movements of the needle bar arm 3, the switching arm 2, and the positioning plate 10 are restricted. At this time, the needle bar 15 that was in the sewing position moves to the non-sewing position, and the recess 15a and the push-down body 16
The projection 16a of the crank lock end 22 and the recess 15 of the needle bar 15 engage with each other.
b is disengaged.

Further, the needle bar 15', which was in the non-sewing position, moves to the sewing position, and is disengaged by the concave portion 15a' and the relief portion 16b of the push-down body 16, and the convex portion 22a of the crank lock end and the needle bar 15' are disengaged from each other. ’ recess 1
5b' is engaged. Then, the suction of the solenoid 20 is released, and the needle bar 15, which is in the non-sewing position, is moved upward by the reverse swinging of the push-down arm 13.
Then, the positioning arm 9 similarly swings, and the right side surface of the recess 9a contacts and engages the right side surface of the pin 11. As a result, the needle bar arm that has been completely switched is fixed.

〔Effect of the invention〕

In order to eliminate the drawbacks of the prior art, it is conceivable to use air to operate the switching dial or to operate it electrically. However, when using air, a separate air source is required, and a large electric drive is also required, and installation to the sewing machine body also interferes with the sewing process.

In the present invention, the tip R portion of the switching arm is sandwiched between the needle bar arm shaft stepped portion and the collar, and the needle bar arm is fixed by the stopper, the stopper plate, the pin, and the positioning arm, so that the needle bar arm cannot move independently. There is no crooked seam or skipped stitches, resulting in stable stitching. Further, there is no need for needle breakage or damage to the needle plate due to needle breakage, resulting in stable work.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of the configuration and functions of the needle bar arm mechanism of the present invention;
Figures 2 and 3 are illustrations of the state of the needle bar during sewing and non-sewing, respectively. Figures 4 and 5 are illustrations of the engagement of the left and right needle bar sewing positioning arms and pins. Figures 6 to 8 are preceding illustrations. It is an explanatory diagram of the technique. DESCRIPTION OF SYMBOLS 1...Switching shaft, 2...Switching arm, 3...Needle bar arm, 4...Collar, 5, 6...Stopper plate, 7, 8...Stopper, 9...Positioning arm, 13...Pushing down arm, 14...
Push-down shaft, 15, 15'... Needle bar, 16... Push-down body, 19... Push-down rod, 20, 23... Solenoid, 22a... Crank rod end convex portion.

Claims (1)

[Claims] 1. A single needle bar arm into which a plurality of needle bars are fitted in a straight line and movable in a direction perpendicular to the cloth feeding direction; In a sewing machine, the sewing machine has a switching shaft that moves a desired needle bar to a sewing state position, and a push-down arm that raises a non-sewing state needle bar among the plurality of needle bars upward and makes it stand still. a positioning arm having a fixed recess; a positioning plate having a plurality of pins fixed to the switching shaft and selectively engaging and disengaging in relation to the recess and the needle bar in the non-sewing state; The needle bar is held between a fixed stopper plate, a stopper that is adjustable and fixed to the machine frame and can come into contact with the stopper plate, and a collar and a needle bar arm shaft fixed to the switching shaft and formed on the needle bar arm. A needle bar arm fixing device for a sewing machine, comprising a switching shaft and a switching arm that links the needle bar arm.