JPS6168080A - Needle rod driver in sewing machine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a needle bar drive device for raising and lowering a needle bar with a sewing needle in a sewing machine.

(Prior art) As a prior art, there is, for example, Japanese Patent Publication No. 59-2791.

(Problems to be Solved by the Invention) In the case of the device disclosed in the above publication, when the stitch loop length is increased or decreased, the upper and lower dead center positions of the needle bar are respectively displaced up and down, so the timing of loop formation is There was a technical problem in that the loop formation operation was uncertain due to fluctuations in the loop formation.

An object of the present invention is to provide a needle bar drive device that solves the above technical problems.

(Means for Solving the Problems) The present invention provides a needle bar drive member connected to a needle bar to which a sewing needle is fixed, in order to drive the needle bar up and down, with a swing fulcrum at a fixed position and a J1vJ action. The needle bar drive member is pivotably supported so as to be able to swing so that a point is displaced, and when the swinging point of the needle bar driving member is displaced, the bottom dead center of the vertical movement stroke of the needle bar is almost constant and the top dead center is fixed. The gist of this invention is a needle bar drive device configured to vary the needle bar drive device.

(Function) The device of the present invention supports a needle bar driving member connected to a needle bar in order to drive the needle bar up and down so that it can swing and its swinging point can be moved, and the swinging point can be moved. When this happens, the swing stroke of the needle bar drive member is increased or decreased at the upper swing end, and the vertical stroke of the needle bar is changed by the displacement of the top dead center.

<Example> Continuing ゛C1 An example of the present invention will be described with reference to the drawings. In the figure, 1 is a needle bar vertically movable with respect to the frame F of the sewing machine head, and 2 is a needle bar 2 at the lower end of the needle bar 1. A sewing needle 3 is fixed to the frame F, and a nipple 3 is perpendicular to the frame F so that it can move up and down and rotate horizontally. The upper piece 4a of the crossed lifting members, whose upper end is bent into an L-shape and extends forward, is connected to a connecting member 5 formed in a bifurcated shape and fitted near the upper end of the needle bar 1. On the other hand, a first engaging member 7 having an engaging groove 6 horizontally formed in the central portion is provided protruding from the rear side near the central portion thereof.

A nipple bar 8 is perpendicular to the frame F on one side of the needle bar 1 so as to be movable up and down, and is normally urged downward by a spring, and a nipple bar 8 extends rearward near the center of the nipple bar. Second
While the engaging member 9 is fixed, a nipple 3 is attached to the lower end of the engaging member 9.
An engaging member 11 is fitted onto the top of the connecting member 10, which is connected to the connecting member 10 so as to be able to move together.

Reference numeral 12 denotes a presser foot bar which is vertically movable relative to the frame on the other side of the needle bar 1, and is normally urged downward by a spring, and has a lower end extending rearward. A third hooking member 13 is fixedly attached, and below the third hooking member 13 is a presser foot 14 which presses the needle base of the fabric in an encircling manner when the fabric is transferred.
are the universal joint 15, the spring 16, and the presser foot support rod 1.
7, and this presser foot 14 is supported via the presser rod 12.
It is moved up and down by the up and down movement of the fabric, and when it moves down, it is horizontally displaced in any direction to transfer the fabric, and when it moves up after the horizontal displacement, it is automatically centripetally returned to its original position by the elastic force of the spring 16. Will be reinstated.

Reference numeral 18 denotes an upper camshaft rotatably mounted horizontally on the rear upper part of the frame F, and is driven to rotate steadily by transmitting the rotation of a driving shaft (not shown).

Reference numeral 19 denotes a support shaft rotatably suspended below the upper cam 18, and is rotationally driven by a stroke change control motor (not shown) whose rotation is controlled based on a stroke change signal.

Reference numeral 20 denotes a lower camshaft that is rotatably mounted horizontally below the support shaft 19, and is rotationally driven by an evacuation control motor (not shown) whose rotation is controlled based on an evacuation signal sent when the upper camshaft 18 is stopped. Ru.

Reference numeral 21 denotes a three-pronged nipple rod drive member that is fitted to one support shaft so as to be able to swing through an eccentric collar 22 that is fitted to the support shaft 19, and extends rearward and upward. The upper arm 21a is movably opposed to the second cam 23 fitted to the upper camshaft 18, while the front arm 21b extending forward is connected to a drive pin fixed to the front end of the front arm 21b. A lower arm 21 is connected to the second engaging member 9 via 26 so as to be able to push up, and further extends downward.
c is movable and spaced apart from a second retraction cam 24 fitted on the lower cam shaft 20, and the upper arm 21a reciprocates ω1 with the constant rotation of the second cam 23, and the front arm 2
1b swings back and forth to move the nipple rod 8 up and down, while when the upper camshaft 18 is stopped and the lower camshaft 20 rotates approximately 90', the lower arm 21c is pushed forward and the front arm 21b is moved upward. When the upper arm 21a and the nipple rod 8 are pulled up above the top dead center of the steady vertical motion and held at the retracted position above the top dead center, and when one of the support shafts is rotated by a predetermined angle, the upper arm 21a and The swinging fulcrum of the front arm 21b is displaced, and the vertical stroke of the nipple rod 8 is increased or decreased.

Reference numeral 25 denotes a presser rod driving member which has almost the same shape as the nipple rod driving member 21 and is fitted to one support shaft so as to be able to swing through an eccentric collar, and includes an upper arm extending rearward and upward. 2
5a is positioned so as to be able to follow a third cam (not shown) fitted to the upper cam shaft 18, while a front arm 25b extending forward is a driving cam fixed to the front end of the front arm 25b. The lower arm (not shown), which is connected to the 311) mating member 13 through the pin 27 so as to be able to push up and move upward, is connected to the third retracting cam fitted to the lower cam shaft 2o. (not shown), the upper arm 25a swings back and forth by ↑1 with the steady rotation of the third cam, and the front arm 25b swings back and forth, so that the While the presser bar 12 moves up and down, when the upper cam shaft 18 is stopped and the lower cam @20 rotates approximately 90', it is pushed forward by the upper and lower arms nη, causing the front arm 25b to swing upward excessively, and the cloth The presser bar 12 is pulled up above the top dead center of steady vertical movement in synchronization with the nipple bar 8 and held at the retracted position above the top dead center, and the spindle 1
When the presser foot a is rotated by a predetermined angle, the swinging fulcrum of the front arm 25b is displaced and the presser foot a! 12 vertical strokes are increased or decreased.

Reference numeral 29 denotes a swing lever that is swingably supported near the rear upper end of the frame F and extends forward, and near the center of the swing lever is a first cam 30 fitted to the upper cam shaft 18. Cam>
The bin 31 engaged with M 30 a is fixed and is reciprocated in the vertical direction by the steady rotation of the first cam 30.

Reference numeral 32 denotes an interlocking lever C fitted to the support shaft 19 so as to be able to swing in opposition to the swing lever 29 via an eccentric collar 33 fitted on the support shaft 19; and the front end of the swinging lever 29 are interlocked via a connecting link 34, and the interlocking lever 32 swings back and forth with the steady rotation of the first cam 30, and the eccentric collar 33 moves to the support shaft 1 in response to a stroke change signal. When the interlocking lever 32 rotates together with the pivot lever 32, the swing fulcrum a of the interlocking lever 32 is displaced around the axis of the support shaft 19.

35 is a two-pronged needle bar drive member fitted so as to be able to swing relative to the support shaft 19, and the front arm 3 extends forward.
A driving pin 36, which is inserted into the engagement groove 6 of the first engagement member 7 of the elevating member 4, is fixed to the front end of the front arm 5a in order to move the needle si up and down. In order to interlock the needle bar driving member 35 and the interlocking lever 32 by engaging the tip 37a of the connecting pin 37 that connects the interlocking lever 32 and the connecting link 34 so as to be slidable in the front-rear direction. A fitting groove 38 formed in a horizontally elongated shape connects the swinging fulcrum a of the interlocking lever 32 and the interlocking lever 32 and the connecting link 34.
The needle bar is recessed along a line connecting the joint fulcrum with the needle bar, and when the interlocking lever 32 swings back and forth, the front needle 35 swings back and forth in the vertical direction, and the needle bar 7 lifts and lowers. On the other hand, when the spindle 19 rotates in response to a stroke change signal and the eccentric collar 33 rotates by a predetermined angle, the connecting link 34 swings and the connecting bottle 37 moves in an approximately linear arc, 1
It is displaced within the medical groove 38.

The connecting center point of the needle bar driving member 35 and the connecting lever 32, the connecting point C of the needle bar driving member 35, and the swinging point C of the needle bar driving member 35 are the respective bottom dead centers of the swinging point C when the connecting bin 37 is displaced. and the axis of one support shaft, that is, the swinging fulcrum of the needle bar drive member 35, the angle of the line segment d1 is always approximately constant, and 1:
The angle of the line segment d2 connecting each top dead center of the H operation point C and the 1E movement fulcrum is set to vary, so that the lower end of the front arm 35a is almost constant and the upper end of the front arm 35a is almost constant. Since the moving end is set to move up and down, 1 of the front arm 35a
The vertical movement stroke of the button frame 1 can be increased or decreased so that the bottom dead center is constant and the top dead center is 1 displacement by increasing or decreasing the movement stroke at the upper swing end, and the vertical movement of the sewing needle 2 can be increased or decreased. The loop length of the stitch formed by can be changed at the upper end of the loop. On the other hand, the lower arm 35b of the needle bar drive member 35 extending downward is always opposed to the needle bar retraction cam 39 fitted on the lower camshaft 20 in a spaced manner.
When the lower camshaft 20 rotates approximately 90' in response to the evacuation signal when the lower arm 35b is stopped, the lower arm 35b is pushed forward and the upper arm 3
5a swings upward excessively, and the needle bar 1 is retracted together with the sewing needle 2 above the top dead center of the steady vertical movement in synchronization with the nipple rod 8 and presser foot drive rod 12, and is held in the retracted state.

Next, the operation and effects of the embodiment having the above configuration will be explained.

Now, in this example, the swinging lever 29 is supported so as to be able to perform steady swinging motion, and the swinging lever 29 is capable of swinging motion with respect to the support shaft 19 whose rotation is controlled based on the stroke change signal, and the swing lever 29 is supported so as to be able to perform steady swinging motion. An interlocking lever 32, which is fitted eccentrically so that the swinging fulcrum a is displaced, is provided so as to be interlocked via a connecting link 34, and the needle bar 1 to which the sewing needle 2 is fixed is moved up and down. The front arm 35a of the four-prong drive member 35, which is connected to the needle bar 1 and fitted in the support shaft 19 for one movement, and the interlocking lever 32, The descending end of the line segment d connecting the fulcrum and the swinging point C is always almost constant, and the rising end of the line segment d fluctuates up and down as the swinging fulcrum a of the interlocking lever 32 moves, causing the front arm to move upward and downward. 35a is connected via a connecting pin 37 and a fitting groove 38 so that the swinging stroke of 35a can be increased or decreased at the upper swinging end.

Therefore, when changing the loop length of the stitch loop formed by the vertical movement of the sewing needle 2, the loop length is expanded or contracted at the upper end side of the stitch loop, and the vertical movement of the sewing needle 2 and the sewing thread are attached to the sewing button 2. The operation of the looper that forms the loop is always in synchronization with the vertical movement stroke of the sewing hook 2, which makes the operation of forming the stitch loop more accurate and stable, and also improves the timing of the loop length change. This has the effect of eliminating the trouble of re-adjusting.

(Effects of the Invention) In other words, the present invention provides a needle bar drive member connected to the needle bar to vertically drive the side bar to which the stitch z1 is fixed, by swinging the needle bar driving member with the pivot point at a fixed position. The needle bar is pivoted so that it can be moved so that its operating point can be displaced, and when the driving point of the needle bar driving member is displaced, the bottom dead center of the vertical movement stroke of the needle bar is almost constant. By configuring the top dead center to vary, there is an effect that the stitch forming operation can be made more accurate and stable.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, in which Fig. 1 is a side sectional view of the main part, Fig. 2 is a front view, and Fig. 3 is a cross-sectional view of the main part.
- X-ray arrow view, Figure 4 is a 1-Y cross-sectional view of Figure 3, Figure 5 is
The figure is an explanatory diagram of the swinging motion of the needle bar driving member. 1... Needle offering 2... Sewing needle 35.
... Needle bar drive member b... Swing fulcrum C... Swing point

Claims (1)

[Claims] The needle bar driving member connected to the needle bar to which the sewing needle is attached is made to be able to swing in such a way that the swinging point is at a fixed position and the swinging point is displaced. The needle bar is pivotably supported, and is characterized in that when the swinging point of the needle bar driving member is displaced, the bottom dead center of the vertical movement stroke of the needle bar is substantially constant and the top dead center varies. A needle bar drive device in a sewing machine.