JP2001334089A - Sewing machine equipped with cutter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely drive a movable cutter arranged in front of a needle location and perform stable hem stitching at high speed also in a sewing machine having the needle location on a small-diameter cylindrical bed. SOLUTION: A cutter shaft 42 is arranged along the front surface of a bed body B having a cylindrical bed B1 projecting from the tip end thereof, which cutter shaft 42 is connected to a cam shaft 50 for driving a thread feeding cam 5 arranged outside the bed body B at the base end side thereof by way of a transmission mechanism having an eccentric ring 53 and a transmission arm 48, a movable cutter of a cutter mechanism 4 is attached to the tip end of the cutter shaft 42 extending to the front position of the cylindrical bed B1, the forward and backward turning of the cutter shaft 42 in accordance with the rotation of the cam shaft 50 is transmitted to the movable cutter so that the cutter appears or disappears in front of the needle location set on the cylindrical bed B1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an edge of a cloth which is moved into and out of a sewing machine bed in front of a needle dropping position, brought into sliding contact with a fixed knife disposed at the position, and fed to the needle dropping position. The present invention relates to a sewing machine with a scalpel configured to cut a sewing machine.

[0002]

2. Description of the Related Art For example, in the case of sewing rubber pants around a waist when sewing sweatpants, pants for infants, or the like, the cloth to be sewn is folded over a predetermined width to the back side. Hem is sewn to the needle drop position, and the edge is sewn to the fabric on the surface side.

In order to carry out such hemming, a movable knife which swings up and down by transmission from a sewing machine main spindle is arranged at a lower front portion of a needle drop position as disclosed in Japanese Patent Application Laid-Open No. 10-287. A sewing machine with a scalpel having a configuration in which a hook-shaped tip blade of the movable scalpel is protruded and retracted on a sewing machine bed and slidably contacts a fixed scalpel arranged at a corresponding position has conventionally been used.

[0004] According to this configuration, the edge of the fabric folded back to the back side for performing the hem sewing is caught by the tip blade portion of the movable knife and is pulled down, and is substantially between the fixed knife and the movable knife. As a result of being cut with a certain turning width, it is possible to stably perform hemming on the edge after cutting with high efficiency.

[0005]

In the above-described sewing machine with a knife, the movable knife has its base end fitted and attached to a knife shaft installed inside a sewing machine bed. The axis is the other movable part (needle,
Like a transmission shaft for a looper, a feed dog, etc.), it is connected to a sewing machine main shaft through a known eccentric mechanism, and is repeatedly rotated within a predetermined angle range in accordance with the rotation of the sewing machine main shaft. With this transmission configuration, the movable knife swings around the axis of the knife shaft in accordance with the rotation of the sewing machine main shaft, and the tip teeth that move up and down due to the swing appear and retract on the sewing machine bed and slide in contact with the fixed knife, The edges of the dough will be cut.

On the other hand, the hem stitch is performed on a tubular sewn material such as the above-mentioned sweatpants and pants for a baby to form a rubber passing portion around the waist. The sewing machine has a configuration in which a tubular bed through which a tubular sewing product can be inserted is protruded on one side of a sewing machine body having a built-in sewing machine spindle, and a needle drop position is set at an upper portion of the tubular bed. It is common.

When the hemming sewing machine having such a tubular bed is configured as a sewing machine with a knife having the movable knife and the fixed knife, the movable knife having an operating area in front of the needle drop position is a sewing cloth. In the conventional case, the transmission shaft for the feed dog is also used as the transmission shaft (female shaft) for the movable knife, and the transmission shaft for the both is used. A mechanism is provided that can be arranged without interference in the limited space inside the cylindrical bed.

However, the size of the tubular bed is determined so that the target tubular sewing product can be inserted, and is applicable to a wide range of sewing including a small-sized tubular sewing product. For this purpose, a sewing machine equipped with a small-diameter cylindrical bed having a diameter of about 180 mm has been commercialized. In such a sewing machine, the transmission shaft for the feed dog inside the cylindrical bed has to be reduced in diameter. As described above, when the transmission shaft is also used as the knife shaft for the movable knife, the transmission shaft is It repeatedly rotates with twisting due to the action of the load applied when cutting with the movable knife, which may hinder not only the cutting operation with the movable knife but also the feeding operation with the feed dog, and stable sewing at high speeds There is a problem that the operation cannot be performed.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and a transmission to a movable knife that appears and disappears in front of a needle drop position is performed through a knife shaft disposed outside a bed main body. Provided is a sewing machine with a knife that can stably perform hem sewing at a high speed without interfering with the cutting operation by the movable knife and the feeding operation by the feed dog even in the configuration having the needle drop position on the bed. The purpose is to do.

[0010]

A sewing machine with a scalpel according to a first aspect of the present invention has a cylindrical shape having a needle drop position set at an upper portion thereof, which protrudes from one side of a bed body containing a main shaft of the sewing machine. A bed, at least a portion of which is arranged so as to protrude outside the bed main body, a transmission shaft that rotates around an axis by transmission from the main shaft of the sewing machine, and a front of the cylindrical bed from a protruding portion of the transmission shaft. Part, a female shaft erected along the front outside of the bed main body, and one end of the female shaft is connected to the projecting portion of the transmission shaft, and the female shaft is rotated in accordance with the rotation of the transmission shaft. A transmission means for repeatedly rotating within a predetermined angle range, and a movable knife attached to the other end of the knife shaft and protruding and retracting at the front of the needle drop position according to the repeated rotation of the knife shaft. Slidably contacts one side of the movable knife and is sent to the needle drop position. Characterized by comprising a fixed knife for cutting the edge of the earth.

[0011] In the present invention, a female shaft erected along the front outer side of a bed body having a cylindrical bed on one side,
The movable shaft is connected to the protruding portion of the transmission shaft to the outside of the bed body via transmission means, and a movable knife is attached to the end of the female shaft extending to the front position of the cylindrical bed, so that the transmission from the sewing machine main shaft is performed. , The knife shaft is repeatedly rotated by the rotation of the transmission shaft, and the repeated rotation is transmitted to the movable knife so as to protrude and retract at the front of the needle drop position.

A sewing machine with a scalpel according to a second invention is characterized in that the transmission shaft of the first invention also serves as a transmission shaft to a threading cam disposed outside the bed body.

In the present invention, the transmission shaft to the threading cam disposed outside the sewing machine bed is also used as the transmission shaft to the female shaft, and a dedicated transmission shaft is not required.

Further, in the sewing machine with a knife according to the third invention, the transmission means according to the first invention or the second invention has an eccentric ring fitted and held on a part of the transmission shaft, and one end fitted on the female shaft. A transmission lever is provided, the other end of which is connected to the eccentric ring, and means for changing a connecting portion of the eccentric ring to the transmission lever in a longitudinal direction of the transmission lever.

In the present invention, the transmission shaft and the female shaft are formed by connecting the eccentric ring fitted and held to the former and the transmission lever fitted to the latter, and the rotation is made according to the rotation of the transmission shaft. The configuration is such that the knife shaft is repeatedly rotated, and furthermore, the connection position between the eccentric ring and the transmission lever can be changed in the longitudinal direction of the transmission lever, and this change reduces the operating stroke of the movable knife caused by the repeated rotation of the knife shaft. Adjust easily.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings showing the embodiments. FIG. 1 is a perspective view showing an entire configuration of a sewing machine with a knife according to the present invention.

The illustrated sewing machine has a sewing machine arm A whose base end is supported by a leg C standing upright on a bed body B.
And a small-diameter cylindrical bed B ₁ protruding from one side of the bed body B so as to be parallel to below the sewing machine arm A.
It has.

A needle bar and a presser bar are supported at the distal end of the sewing machine arm A by hanging. A plurality of needles 1, 1... Are provided at the lower end of the needle bar, and a presser foot is provided at the lower end of the presser bar. 2 are attached respectively. The upper surface of the cylindrical bed B ₁ represents the needle 1, 1 and the needle plate 3 below the position of the presser foot 2 (see FIG. 2) are laid, needle plate 3 below the cylindrical bed B ₁
A looper and a feed dog (not shown) are built in the inside.

The needles 1, 1... Move up and down by a predetermined stroke including the up and down of the needle plate 3 together with the needle bar by transmission from an upper shaft (not shown) provided inside the sewing machine arm A. There is something. The presser foot 2 is lowered onto the needle plate 3 by a predetermined operation, and clamps the cloth W (see FIG. 4) fed from the front onto the bed body B between the needle plate 3 and the bed body B. There is something.

The flat stitch sewing machine configured as described above is
As shown in FIG. 1, and a knife mechanism 4 to the distal end front side of the cylindrical bed B _1. FIG. 2 is a perspective view showing a configuration of a main part of the knife mechanism 4 together with a needle plate, and FIG. 3 is an exploded perspective view of the knife mechanism 4.

2 in FIG. 2 is a cylindrical bed B _{1 as} described above.
Is a needle plate erected on the upper surface of the distal end of the needle plate. The needle plate 3 includes
The needles 1, 1... Which move up and down as described above are individually inserted into the approximate center thereof when descending.
Are formed side by side in the width direction, and the needle drop positions are set. The front and rear and left and right sides of the needle drop position are rectangularly opened to project a feed dog (not shown). Are formed.

The cloth W (see FIG. 4) is fed onto the needle plate 3 from one side (front side) in the longitudinal direction to the other side (rear side) as shown by the white arrow in FIG. The cloth W is sandwiched between the needle plate 3 and the presser foot 2 (see FIG. 1) descending above the needle plate 3, and the feed hole
The intermittent feed at a predetermined stroke is applied by a feed dog (not shown) projecting from the needles 31, 31 onto the needle plate 3, and the needles 1 descending to the needle drop holes 30, 30,.
1 and the operation of a looper (not shown) arranged below the needle plate 3.

The knife mechanism 4 includes a knife base 40 which is fixed to the front (projecting side of the tubular bed B ₁₎ the distal end side of the bed body B,
A shaft abutment 41 (see FIG. 1) fixed to the base end front surface of the bed body B so as to correspond to the stool table 40, and a scalpel erected along the outer front surface of the bed body B therebetween. Axis 42,
A movable knife 43 whose base end is fitted to a protruding portion of the knife shaft 42 from the knife table 40, and one side of the movable knife 43 (right side in the figure)
The movable knife 43 is operated by a transmission described below from a sewing machine main shaft (not shown), and is brought into sliding contact with the fixed knife 44 so as to be fed onto the needle plate 3. The edge is cut off.

The knife base 40 as shown in FIG. 2, by a plurality of screws are fastened to the distal end side front surface of the bed body B, is positioned on the right side of the needle plate 3 is bridged over tubular bed B ₁ It is. The female shaft 42 has a pair of support brackets 40a, 40a provided on the knife base 40 at two locations separated in the axial direction on the distal end side, and one of the base supports 41 at the proximal end side.
As a result, they are supported along the front surface of the bed body B as described above.

As shown in FIG. 2, the distal end of the female shaft 42 crosses the front position of the needle plate 3 in a direction substantially perpendicular to the feeding direction of the cloth W, and the needle drop position set on the needle plate 3 It protrudes to the left.

The movable knife 43 is provided with a blade 43a which is bent in a hook shape at the tip, a base is fixed to a protruding end of the knife shaft 42, and the knife shaft 42 is repeatedly rotated by transmission which will be described later. And the blade portion 43a is moved up and down in response to the pressure. The needle plate 3 is formed with a rectangular notch 32 by notching the left front part of the needle drop holes 30, 30... To an appropriate width, and the blade part 43a at the tip of the movable knife 43 is moved upward. ,
As shown in FIG. 2, it projects above the needle plate 3 through the notch 32.

The fixed knife 44 is, as shown in FIG.
A plate-shaped member having a blade portion 44a on one edge in the longitudinal direction, which is attached to a fixed table 45 supported by the knife table 40 adjacent to the mounting position of the movable knife 43, as shown in FIG. Needle plate 3
The blade portion 44a is disposed along the side edge of the notch 32 on one side, and the blade portion 44a slides from one side on the blade portion 43a of the movable knife 43 that moves up and down as described above, The sliding contact portion is configured to perform a cutting action.

FIG. 4 is an explanatory view of the cutting state of the cloth by the movable knife 43 and the fixed knife 44. As shown in the figure, this cutting is performed on the fabric W sent to the needle drop position with its edge E folded back to the back side, and when performing the hem sewing, the folded portion is sewn to the front side of the fabric W. ,
Before reaching the needle drop position indicated by the one-dot chain line in the drawing, the folding edge E is cut so as to leave a folded portion having an appropriate width.

The movable knife 43 which moves up and down at the position before the needle drop position pushes up the cloth W from the back side at the time of upward movement, and the blade which bends the vicinity of the folded edge E of the cloth W into a hook shape. It is grasped by the portion 43a, and in this state, it is moved downward as shown by the arrow in the figure, and is guided to the sliding contact portion of the fixed knife 44 with the blade portion 44a to be cut. This cutting is continuously performed by the vertical movement of the movable knife 43 generated in a short cycle by the transmission from the knife shaft 42, and hemming is performed on the edges trimmed by the cutting.

As shown in FIG. 2, in the middle of the female shaft 42,
A spring receiving ring 46 is coaxially fitted and fixed between the pair of support brackets 40a, 40a of the knife table 40, and is provided between the spring receiving ring 46 and the support bracket 40a on the distal end side. A coil spring 47 is interposed, and the female shaft 42
Is the coil spring 47 which is applied to the fitting portion of the spring receiving ring 46.
Is biased rightward when viewed from the base end side, that is, from the front side. By this biasing, the movable knife 43 at the tip of the knife shaft 42 moves up and down with its blade portion 43a pressed against the blade portion 44a of the fixed knife 44, and the both blade portions 43a, 4
The cloth W can be reliably cut between 4a.
The fixing position of the spring receiving ring 46 can be changed in the axial direction of the female shaft 42. With this change, the spring force of the coil spring 46 is increased or decreased, and the pressing force of the blade portions 43a, 44a is set appropriately. I can do it.

As described above, the transmission to the knife shaft 42 for moving the movable knife 43 up and down is performed in the vicinity of the base end portion supported by the shaft support 41. As shown in FIG. 1, a thread reeling cam 5 is disposed below a shaft support 41 fixed to the front surface on the base end side of the bed body B. This threading cam 5
Rotating by transmission from a sewing machine main shaft (not shown) supported inside the bed body B, intermittently increasing and decreasing the tension of the looper thread supplied to the looper operating under the needle drop position. The cam shaft 50 is fixed to one end (left end) of a cam shaft 50 erected in parallel to the female shaft 42 on the front surface on the base end side of the bed body B.

The cam shaft 50 is provided with a leg C of the sewing machine arm A.
Is supported by a support table 51 fixed to the front surface of the bed body B and located at a lower part of the bed body B so as to be rotatable around the axis at two places separated in the axial direction. The other end (right end) of the camshaft 50
Is extended beyond the base end face of the bed body B and is connected via a timing belt 52 to a sewing machine spindle (not shown) projecting from the same end face. With the above configuration, the camshaft
Reference numeral 50 rotates around the shaft by transmission from the main shaft of the sewing machine, and functions as a transmission shaft for continuously rotating the thread winding cam 5 fitted to the left end in one direction.

On the front surface of the bed body B, a thread path plate 53 for looper thread is attached at a position corresponding to the thread winding cam 5 rotating as described above, and the thread winding cam 5 is rotated during its rotation.
It is positioned on the upper surface of 53 so that it appears and disappears appropriately. A looper thread is supplied to the thread path plate 53 from a thread tensioner 6 attached to the front surface of the leg C of the sewing machine arm A, and the looper thread is traversed across the position where the thread reeling cam 5 appears and retracts. We are led to the looper inner tubular bed B ₁ through the interior of the. With this configuration, the looper thread is pushed up by the thread reeling cam 5 when the thread reeling cam 5 protrudes above the thread trailing plate 53, and is relaxed when the thread reeling cam 5 is lowered from above the thread trailing plate 53. The looper thread whose tension is increased or decreased according to the operation of the looper is supplied.

In the sewing machine with a knife according to the present invention, the knife shaft 42 of the movable knife 43 uses the cam shaft 50 of the thread reeling cam 5 operating as described above as a transmission shaft, and falls within a predetermined angle range as described above. To rotate repeatedly.

FIG. 5 is an enlarged perspective view of a main part showing a connection relationship between the female shaft 42 and the cam shaft 50. In this figure, in order to clearly show the connecting portion, the thread reeling cam 5 fitted to the tip of the cam shaft 50 and the thread path plate 53 on which the thread reeling cam 5 appears and disappears.
Are not shown.

As shown in the figure, the transmission means from the camshaft 50 as the transmission shaft to the female shaft 42 of the movable knife 43 is formed by an eccentric ring 54 fitted and held in the middle of the camshaft 50 and a female shaft 42. A transmission lever 48 having a base end fitted to the portion thereof, and a distal end of the transmission lever 48 connected to the eccentric ring 54, more specifically, to a distal end of an arm 55 protruding from the eccentric ring 54. It is configured.

The eccentric ring 54 is a well-known well-known method widely used in various parts of the sewing machine for transmitting power from a shaft rotating in one direction, such as the main shaft of the sewing machine, to a repetitively moving movable part such as a needle, a looper, a feed dog or the like. Mechanical elements. Ecsen ring shown
54 is fitted and held on a cam shaft 50 that rotates in one direction,
The rotation of the cam shaft 50 is taken out to the arm 55 of the eccentric ring 54 as a reciprocating motion of a predetermined stroke in the length direction,
This reciprocating action acts on the tip of the transmission lever 48. As a result, the transmission lever 48 swings about the female shaft 42 to which the base end is fitted as a pivot, and the female shaft 42 responds to this swing in an angle range corresponding to the swing angle of the transmission lever 48. The rotation is repeated, and the repeated rotation is transmitted to the movable knife 43 attached to the distal end portion, and the cutting operation described above is performed.

Here, in the sewing machine with a knife according to the present invention, the transmission to the movable knife 43 is performed via the cam shaft 50 and the knife shaft 42 extending along the front surface of the bed body B,
Since these shafts 50 and 42 are located outside the bed body B, the size including the diameter can be freely selected. Therefore, there is no fear that the cutting operation is hindered by a large load applied to the movable knife 43 during the cutting. Further, a cylindrical bed B ₁ protruding from the tip side of the bed body B ₁
The internal feed dog can be operated by transmission from a dedicated transmission shaft, and there is no risk of interfering with the feed operation, and stable hemming can be performed even at high speed.

In the above embodiment, the cam shaft 50 for transmission to the threading cam 5 disposed outside the bed body B is also used as the transmission shaft to the knife shaft 43. No transmission shaft is required, and the configuration can be simplified. The arrangement of the thread reeling cam 5 outside the bed body B facilitates the setting of the looper thread guided from the thread tensioner 6, and facilitates the cleaning of the looper thread during the sewing operation. Therefore, this is an arrangement conventionally used.

As shown in FIG. 5, the transmission lever 48 is connected to the arm 55 of the eccentric ring 54 through a long hole 49 extending in the longitudinal direction of the transmission lever 48. The connection position can be changed within the length range. With this configuration, the swing angle of the transmission lever 48, which is caused by the reciprocating movement of the tip of the arm 55 of the eccentric ring 54, can be changed within the length range of the long hole 49.
The up and down stroke of the movable knife 43 generated through the transmission via the blade 42 can be adjusted according to, for example, the type of the target fabric W, so that a good cutting state can always be obtained.

FIG. 6 is an external perspective view showing another embodiment of a sewing machine with a scalpel according to the present invention. In this embodiment, a thread reeling cam 5 is attached to a cam shaft 50 protruding from one surface of a leg C of a sewing machine arm facing a needle drop position, and an eccentric ring 54 is attached to an extended end of the cam shaft 50. The tip of the arm 55 extending forward from the eccentric ring 54 is connected to the tip of the arm 55 extending above the transmission lever 48 fitted on the female shaft 42 provided on the front surface of the bed body B. The configuration is such that the female shaft 42 is repeatedly rotated in accordance with the rotation of the shaft 50. The cam shaft 50 is extended through the peripheral wall into the inside of the leg portion C, and this extended end is connected to a sewing machine main shaft inside the bed body B by a timing belt,
It rotates in one direction according to the rotation of the main shaft of the sewing machine. In this embodiment, other components are the same as those in the embodiment shown in FIG.
The same reference numerals are given and the detailed description is omitted.

In FIG. 6, the eccentric ring 54 is located outside the threading cam 5 and is arranged so as to close a part of the front surface of the threading cam 5. The threading cam 5 and the eccentric ring 54 may be fitted and held so that the former is on the outside, and the front face of the threading cam 5 may be opened as in FIG. With this arrangement, it is easy to set the looper thread on the thread reeling cam 5 and dispose of the looper thread broken during sewing.

[0043]

As described in detail above, in the sewing machine with a scalpel according to the first invention of the present invention, a scalpel extending along the front outer side of the bed body having the cylindrical bed on one side is attached to the scalpel. An outer end of the female shaft connected to a projecting portion of the transmission shaft via a transmission means, transmitting rotation of the main shaft of the sewing machine to the female shaft via the transmission shaft, and extending to a front position of the cylindrical bed. The movable scalpel attached to the knives is made to protrude and retract at the front of the needle drop position. Cutting operation can be performed stably, and there is no risk of interfering with the feeding operation by the feed dog inside the cylindrical bed, and it is possible to perform stable hem sewing at high speed. Become.

In the sewing machine with the knife according to the second aspect of the invention, the transmission shaft for the threading cam disposed outside the bed body is also used as the transmission shaft for transmitting to the knife shaft. It is not necessary to newly provide a transmission shaft, and a stable cutting operation can be performed with a simple configuration.

Further, in the sewing machine with the knife according to the third invention, the transmission means from the transmission shaft to the knife shaft is formed by connecting the eccentric ring fitted and held to the former and the transmission lever fitted to the latter. Since the connecting portion of the eccentric ring to the transmission lever can be changed in the longitudinal direction of the transmission lever, the amount of repetitive rotation of the knife shaft generated by transmission from the transmission shaft and the movable knife generated by this repetitive rotation The present invention has an excellent effect, for example, such that the operation stroke can be easily adjusted, and reliable cutting can be performed regardless of the type of the fabric.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an overall configuration of a sewing machine with a scalpel according to the present invention.

FIG. 2 is a perspective view showing a configuration of a main part of a knife mechanism provided in the sewing machine with a knife according to the present invention, together with a needle plate.

FIG. 3 is an exploded perspective view of a main part of the knife mechanism shown in FIG. 2;

FIG. 4 is an explanatory diagram of a cut state of a cloth by a movable knife and a fixed knife.

FIG. 5 is an enlarged perspective view of a main part showing a connection relationship between a knife shaft and a cam shaft.

FIG. 6 is an external perspective view showing another embodiment of a sewing machine with a scalpel according to the present invention.

[Explanation of symbols]

1 Needle 3 Needle plate 4 Knife mechanism 5 Threading cam 40 Knife table 41 Shaft support 42 Knife shaft 43 Movable knife 44 Fixed knife 50 Cam shaft (transmission shaft) A Sewing arm B Bed body B ₁ Cylindrical bed W Fabric

 ────────────────────────────────────────────────── ─── Continued on the front page F term (reference) 3B150 AA05 BA02 BA12 CB06 CE01 CE04 CE24 CE25 CE27 EE02 EE08 EE11 EE15 JA20 JA28 JA33

Claims (3)

[Claims] 1. A cylindrical bed having a needle drop position set at an upper portion thereof and protruding from one side of a bed body containing a main shaft of a sewing machine, at least a part of which is projected outside the bed body. A transmission shaft that rotates around the shaft by transmission from the main shaft of the sewing machine, and is erected along a front outer side of the bed main body from a protruding portion of the transmission shaft to a front portion of the cylindrical bed. A transmitting means for connecting one end of the female shaft to a protruding portion of the transmission shaft, and for repeatedly rotating the female shaft within a predetermined angle range according to the rotation of the transmission shaft; A movable knife that is attached to the other end of the shaft and that protrudes and retracts in front of the needle drop position in response to the repetitive rotation of the knife shaft; And a fixed knife for cutting the edge of the fabric to be cut. Rumesu with a sewing machine. 2. The sewing machine with a scalpel according to claim 1, wherein the transmission shaft also serves as a transmission shaft for a threading cam disposed outside the bed main body. 3. The transmission means comprises: an eccentric ring fitted and held on a part of the transmission shaft; and a transmission lever having one end fitted to the female shaft and the other end connected to the eccentric ring. The sewing machine with a knife according to claim 1 or 2, further comprising means for changing a connecting portion of the eccentric ring to the transmission lever in a longitudinal direction of the transmission lever.