JP3024087B2 - Needle bar lever transmission in sewing machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a needle bar lever transmission in a sewing machine, and more particularly to a needle bar lever transmission in a sewing machine capable of reducing wear of parts and improving transmission efficiency.

When performing a sewing operation, a sewing needle of a sewing machine is
By reciprocating up and down from the arm portion of the sewing machine toward the bed of the sewing machine, sewing is performed in accordance with the needle at the bottom. Generally speaking, a sewing needle is provided at a lower end of a needle bar, the needle bar is fitted to a bushing provided on an arm portion of the sewing machine, and protrudes to the outside via the inside of the casing. The needle bar swings the swing lever back and forth along an arc-shaped trajectory by rotation of a main shaft of the sewing machine and conversion of a crank or / and a cam. The reciprocating swing of the swing lever is converted into a linear reciprocating vertical movement of the needle bar by the conversion driving means. The needle bar lever transmission device in the sewing machine of the present invention is a conversion drive device for converting the reciprocating swing of the swing lever into a linear reciprocating motion of the needle bar by a conversion drive means. , Sewing.

[0003]

2. Description of the Related Art Japanese Utility Model Publication No. 5-10788 discloses a needle bar driving device for a sewing machine. As shown in FIG. 9, the needle bar driving device includes a needle bar 103, a swing arm 102, and a connecting pin 104, and a U-shaped guide member 130 is provided at an upper end of the needle bar 103. A pair of intersecting brackets 121 is provided at the tip of the bracket 102, and a through hole 122 is formed at the tip of the bracket 121. In the middle part of the connecting pin 104, a flat surface 141 whose both surfaces are concave is formed. By inserting the connecting pin 104 into the through hole 122 and fitting the guide member 130 to the flat surface 141, the reciprocating swing of the swing arm 102, which is an arc-shaped trajectory, causes the needle bar 103 to reciprocate up and down. Can be converted to The angle of the connection pin 104 is changed by the through hole 122
The horizontal displacement between the arc-shaped trajectory of the swing arm 102 and the linear trajectory of the needle bar 103 causes the flat surface 141 of the connecting pin 104 to slide back and forth on the guide member 130. Are offset by In this configuration, the cutting stress and the torsional stress are concentrated on the flat surface portion of the connection pin 104, and the connection pin 104 always slides in the guide member 130. Note that the swing arms 1 fitted to each other
02, in order to accurately operate the needle bar 103 and the connecting pin 104, the requirements for the processing accuracy of the through hole 122, the guide member 130, and the flat surface 141 are extremely high, so that manufacturing, maintenance, and maintenance are more difficult. Become.

[0004] A needle bar drive of a sewing machine is disclosed in Taiwan Patent No. 280841. As shown in FIG. 10, the needle bar driving device includes a swing arm 202, a needle bar 203, and a guide pin 204, and a long cylindrical connecting bar 221 is provided at the tip of the swing arm 202. 203, a pair of intersecting brackets 230 is provided at the upper end thereof.
03 are provided with holding holes 231 respectively. A guide hole 241 is formed through an intermediate portion of the guide pin 204. By inserting the guide pin 204 into the holding hole 231 and inserting the connecting rod 221 into the guide hole 241, the arc-shaped trajectory of the swing arm 202 can be converted into a vertical reciprocating movement of the needle bar 203. The change in the angle is offset by the rotation of the guide pin 204 in the holding hole 231, and the lateral displacement between the arc-shaped trajectory of the swing arm 202 and the linear trajectory of the needle bar 203 is changed by the connecting rod 221.
Are offset by sliding back and forth in the guide hole 241. In this configuration, since the cutting stress concentrates on the connecting rod 221 and slides constantly in the guide hole 241, the connecting rod 221 may be bent or cut. The connecting rod 221 and the guide hole 241
Since the demand for processing accuracy is extremely high, manufacturing, maintenance and maintenance are more difficult.

[0005]

SUMMARY OF THE INVENTION In the prior art,
Sewing machines or overlocks must accommodate high speed sewing of thick or thin fabrics depending on the market. In particular, for thick and hard fabrics, for example, jeans and # 12 to # 16 pounds of fabric wear very quickly on the needle bar lever of the sewing machine and are prone to noise.

SUMMARY OF THE INVENTION It is a primary object of the present invention to provide a needle bar lever transmission for a sewing machine which is simpler, easier, and more effective than the conventional sewing machine.

It is another object of the present invention to provide a needle bar lever transmission for a sewing machine which reduces power loss and improves transmission efficiency.

It is another object of the present invention to provide a needle bar lever transmission in a sewing machine which reduces wear of parts as much as possible and also reduces failure and noise.

[0009]

A feature of the present invention is that the connecting portion at the tip of the swing arm of the needle bar lever transmission is changed to a slide groove, and the conventional fitting means is not used. . This makes it possible to maintain a state in which the direction in which the force of the needle bar is received always coincides with the direction of movement. By providing the guide device in the middle of the movement trajectory of the needle bar, the movement trajectory of the needle bar can be maintained in a required linear shape.
In this way, the resistance caused by the instantaneous insertion of the sewing needle into the cloth can be cancelled, and the moment caused by the resistance can prevent the bushing of the casing from being damaged, and can also prevent noise caused by wear.

In order to achieve the above object, a needle bar lever transmission in a sewing machine according to the present invention includes a swing lever, a needle bar, and a guide pin, and the guide pin is provided in a guide hole at a tip end of the needle bar. Fitted, forming a flat slide portion at each end of the guide hole, forming a bracket at the tip of the swing arm, and forming a slide groove at each of two parallel branch portions of the bracket, 2 above
The two slide portions are slidably fitted in the slide grooves. As a result, the swing lever, the needle bar and the guide pin are connected to each other, the guide pin makes an angular rotation in the guide hole at the upper end of the needle bar, and the slide portions located at both ends of the guide pin have two swing levers. By performing a linear sliding motion in the slide groove, the reciprocating swinging motion of the swinging lever can be converted into a linear vertical reciprocating motion of the needle bar.

The needle bar lever transmission of the sewing machine according to the present invention is such that a guide pin is fitted into a single guide hole, and slide portions at both ends of the guide pin are fitted into open slide grooves. It can respond to the demand for accuracy when connecting parts. Since the guide pin slides in the two slide grooves of the swing lever, and a relatively large portion between the guide pins rotates in the guide hole of the needle bar, the guide pin acts on the guide pin and its relative connection portion. Cutting or excessive abrasion can be reduced because the applied stress can be effectively dispersed.

By attaching a guide piece to the movement trajectory of the needle bar, the guide piece can be slidably fitted to a guide rail at the upper end of the needle bar. The guide piece and the guide rail of the needle bar are joined so that the needle bar can slide up and down when the needle bar moves, so that the movement of the needle bar is made linear as required, and the bushing of the casing and the needle bar itself are formed. Wear and noise due to them can be reduced.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIGS. 1 and 2, a needle bar lever transmission 1 in a sewing machine according to the present invention
Is installed in the arm portion 12 of the sewing machine 10 and reciprocates up and down on the support swing shaft 16 as a fulcrum through the conversion of the crank or / and the cam by the rotation of the main shaft 14 of the sewing machine 10, whereby the needle bar 3 and the The connected sewing needle 13 is linearly reciprocated up and down.

As shown in FIGS. 3 and 4, the needle bar lever transmission 1 in the sewing machine according to the present invention includes a swing lever 2, a needle bar 3, a guide pin 4, and a guide piece 5.
By forming a shaft support hole 22 at one end of the swing lever 2, the swing lever 2 is fixed to the support swing shaft 16. , Can reciprocate up and down. At the other end of the swing lever 2, a cross-shaped bracket 24 is formed. The bracket 24 is mounted on the swing lever 2.
And two bracket branch portions 25 formed in parallel with each other, and a slide groove 26 substantially parallel to the swing lever 2 is formed in each of the bracket branch portions 25.

A guide hole 32 and a guide rail 34 are formed at the upper end of the needle bar 3. The guide rail 34 has an L-shape and is connected to the tip of the guide hole 32.
Since the needle bar 3 is fitted into a bushing 18 provided on the casing of the arm portion 12 of the sewing machine 10, it can be extended to the outside of the casing. A sewing needle 13 of a sewing machine is connected to a lower end of the needle bar 3.

A flat slide portion 42 is formed at each end of the guide pin 4 to make both upper and lower surfaces flat, and the width in the vertical direction is substantially equal to the slide groove 26 of the swing lever 2. In the vertical direction. The intermediate portion of the guide pin 4 is inserted into the guide hole 3 at the upper end of the needle bar 3.
2 and the slide portion 42 is slidably fitted in the slide groove 26 of the swing lever 2. Thereby, the swing lever 2, the needle bar 3, and the guide pin 4 are connected to each other.

The guide piece 5 is connected to the sewing machine 10.
Is fixed in the casing of the arm section 12 and is L-shaped, and is fitted to the guide rail 34 at the upper end of the needle bar 3 so as to be slid up and down.

As shown in FIGS. 6, 7, and 8, the swing lever 2 swings up and down by the support swing shaft 16. At this time, the guide hole 32 at the upper end of the needle bar 3 and the guide pin 4 relatively rotate and slide, and the two slide grooves 26 of the swing lever 2 and the two guide pins 4
The two sliding portions are in a linear parallel sliding state.
Due to the interlocking relationship between the swing lever 2, the needle bar 3, and the guide pin 4, the swing lever 2
The sewing operation is performed on the cloth M by changing the state of reciprocating swinging up and down by the driving of the needle 6 into a linear up and down reciprocating movement of the needle bar. Since the guide piece 5 and the guide rail 34 at the upper end of the needle bar 3 are joined so as to slide up and down, the needle bar 3 can maintain a more linear vertical reciprocating motion. Since the lateral resistance of the swing lever 2 to the movement of the needle bar 3 is eliminated, the needle bar 3
Wear between the and the bushing 18 can be reduced.

As shown in FIGS. 7 and 11, when the present invention is compared with a conventional needle bar lever transmission, a point is reached where the swing lever 2 and the needle bar 3 are orthogonal to each other (ie, the needle bar 3 It is understood from the present invention that the pressing force P1 transmitted to the needle bar 3 of the swing lever 2 is concentrated on the axis of the swing lever 2 (see FIG. 7). Therefore, wear and noise between the needle bar 3 and the bushing 18 can be eliminated without the needle bar being distorted by the moment. On the other hand, in the prior art, the pressing force P transmitted to the needle bar 3 of the swing lever 2 is
Since the rod 2 is separated from the axis by the distance e, a moment is generated and the needle bar 3 is distorted, easily worn, and easily generates noise.

The present invention is not limited to the above embodiments, and other changes can be added to the embodiments without departing from the scope of the present invention. Therefore, the appended claims should be construed broadly in a manner consistent with the scope of the invention.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a relative position of a needle bar lever transmission and a sewing machine in a sewing machine of the present invention.

FIG. 2 is a front view showing a connection relationship between a needle bar lever transmission and a correlated drive mechanism in the sewing machine of the present invention.

FIG. 3 is a perspective view showing a needle bar lever transmission in the sewing machine of the present invention.

FIG. 4 is an exploded view showing a needle bar lever transmission in the sewing machine of the present invention.

FIG. 5 is a top view showing a needle bar lever transmission in the sewing machine of the present invention.

FIG. 6 is a schematic side view showing the motion state of the needle bar lever transmission in the sewing machine of the present invention, and is a diagram showing a state where the needle bar is located at the highest point.

FIG. 7 is a schematic side view showing a motion state of the needle bar lever transmission in the sewing machine of the present invention, and is a diagram showing a state where the needle bar is located at an intermediate point.

FIG. 8 is a schematic side view showing the motion state of the needle bar lever transmission in the sewing machine of the present invention, and is a diagram showing a state where the needle bar is located at the lowest point.

FIG. 9 is a three-dimensional exploded view showing a conventional technique.

FIG. 10 is a three-dimensional exploded view showing another conventional technique.

FIG. 11 is a schematic side view showing a motion state when a needle bar is located at an intermediate point in a conventional technique.

[Explanation of symbols]

Reference numeral 1: Needle bar lever transmission device, 2: swing lever, 3: needle bar,
4 ... guide pin, 5 ... guide piece, 10 ... sewing machine, 12 ...
Arm part, 13 ... sewing needle, 14 ... main shaft, 16 ... support swing shaft, 18 ... bushing, 22 ... shaft support hole, 24 ... bracket, 25 ... bracket branch part, 26 ... slide groove, 32
... guide holes, 34 ... guide rails, 42 ... slide parts.

Claims (5)

(57) [Claims] 1. A needle bar and a sewing needle connected thereto are linearly moved up and down by reciprocatingly swinging up and down around a supporting swing axis by rotation of a main shaft of the sewing machine, which is installed in an arm portion of the sewing machine. In the needle bar lever transmission of the sewing machine configured to reciprocate in a direction, the pivot lever is fixed to the support pivot shaft by forming a pivot support hole at one end of the pivot lever. At the other end of the swing lever, a bracket consisting of two bracket branches formed parallel to the swing lever is formed, and a slide groove is substantially formed at each of the bracket branches. A guide hole and a guide rail are formed at the upper end of the bar, a sewing needle 13 of a sewing machine is connected to a lower end of the needle bar, and flat slide portions are formed at both ends of the guide pin, respectively. By fitting the intermediate portion into the guide hole at the upper end of the needle bar, and fitting the slide portion slidably into the slide groove of the swing lever,
The needle bar is connected to the swing lever, and the guide piece is fixed in the casing of the arm portion of the sewing machine, and slides up and down by being fitted to the guide rail at the upper end of the needle bar. The swing lever is reciprocally swingable up and down by the support swing shaft, and the guide hole at the upper end of the needle bar and the guide pin are relatively slid in a sliding state. Since the two slide grooves and the two slide portions of the guide pin are in a linear parallel slide state, the state in which the swing lever reciprocates up and down is changed to a linear up and down reciprocating movement of the needle bar. The sewing operation is performed, and the guide piece and the guide rail at the upper end of the needle bar are joined so as to slide up and down, so that the needle bar can further maintain a linear vertical reciprocating motion. The needle bar lever transmission in emissions. 2. The needle bar lever transmission of a sewing machine according to claim 1, wherein the slide groove of the swing lever is formed substantially in parallel with the swing lever. 3. The sliding section of the guide pin has flat upper and lower surfaces, and the vertical width of the sliding section substantially corresponds to the vertical width of the sliding groove of the swing lever. The needle bar lever transmission of the sewing machine according to claim 1, wherein 4. The sewing machine according to claim 1, wherein the needle bar is fitted to a bushing provided on a casing of an arm portion of the sewing machine, and thus is extended out of the casing.
The needle bar lever transmission of the sewing machine according to claim 1. 5. The guide bar and the guide piece of the needle bar are L
The needle bar lever transmission in the sewing machine according to claim 1, wherein the needle bar lever transmission is formed in a letter shape.