Threading device of sewing machine

A threading device of a sewing machine having a plurality of needles is provided. The threading device is configured to insert a thread through an eye of any one of the needles. The threading device includes a threading hook which moves forward to enter the eye of one of the needles and moves backward to catch and insert the thread through the eye, a threading mechanism which moves the threading hook to insert the thread, a selecting portion operable to select, among the plurality of needles, a needle through which the thread is to be inserted, a positioning mechanism which moves the threading hook to a position corresponding to the needle selected by operating the selecting portion, and a selected needle indicating device which distinguishably indicates the needle with respect to which the threading hook has been positioned by operating the selecting portion.

CROSS-REFERENCE TO RELATED APPLICATION(S)

The present application claims priority from Japanese Patent Application No. 2007-184444 filed on Jul. 13, 2007 and Japanese Patent Application No. 2008-053411 filed on Mar. 4, 2008, the entire contents of which are incorporated herein by reference.

FIELD OF INVENTION

The present invention relates to a threading device of a sewing machine which can insert a thread with respect to a plurality of needles, eyes of which being different in height.

DESCRIPTION OF RELATED ART

In a sewing machine including a plurality of needles, the respective needles have different heights of eyes and are disposed at a regular interval in a direction intersecting a cloth feeding direction. A related art threading device for inserting a thread through each of the needles has a configuration disclosed, for example, in JP 10-137482 A Publication. More specifically, a threading shaft having a lower end provided with a threading hook for inserting a thread into an eye of a needle is supported to enable a vertical motion and a rotating operation with respect to an oscillating base which is oscillatably supported on a sewing machine frame. The threading shaft is provided with a threading lever having a cam groove formed in an oblique direction and enabling an operation downward, a threading guide for determining a height of the threading hook in a threading operation, and a transverse switching cam for oscillating the oscillating base by a manual operation in relation to each other.

The threading hook catches an end of a thread on a tip of the threading shaft when the threading shaft is rotated in one direction to insert the thread through the eye of the needle, and the threading shaft is rotated in the other direction to slip out of the eye, thereby pulling the caught thread into the eye to implement a threading operation.

A pin to be engaged with the cam groove of the threading lever is protruded from the threading shaft, and furthermore, a guide pin for abutting on an abutting surface of the threading guide is provided in the middle of a downward motion. For this reason, when the threading shaft is moved downward by a downward moving operation of the threading lever, the guide pin abuts on the threading guide in the middle of the downward movement so that the downward movement of the threading shaft is blocked. When the threading lever is operated downward, furthermore, the threading shaft is rotated in the one direction with respect to the threading lever to move the threading hook forward by means of the pin to be engaged with the cam groove.

The (two) needles have different arrangements in the direction intersecting the cloth feeding direction and the eyes also have different heights. In the threading device, therefore, two abutting surfaces having different heights are provided on the threading guide and the oscillating base is oscillated by the manual operation of the transverse switching cam to change a position of the threading shaft so that the guide pin is caused to abut on one of the abutting surfaces to enable the threading hook to correspond to the height of the eye and the arrangement of each of the needles.

In another related art threading device disclosed in JP 06-49114 B2 Publication, a horizontal shaft is provided on a sewing machine frame close to a vertical moving path of a needle and a threading member having a threading hook on a lower end is supported to be rotatable and oscillatable around the horizontal shaft. There has been known a configuration in which the threading member is moved over an arcuate track in an oblique direction and the threading hook can be inserted into eyes corresponding to positions of two needles.

According to the related art threading devices described above, however, a needle with respect to which the threading shaft or the threading member is set cannot be visually checked reliably after a switching operation unless the threading lever or an operation knob is actually operated to carry out a threading operation. For this reason, general users of the sewing machine of this type at home cannot carry out the threading operation at ease so that it is necessary to previously execute the threading operation by way of trial, resulting in a reduction in a working efficiency.

In a sewing machine having a large number of needles (e.g., three or more needles), in particular, it is necessary to carry out a work for confirming the needle with respect to which the threading member is set.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a threading device for a sewing machine having a plurality of needles, the threading device being configured to allow a user to easily confirm a needle through which a thread is to be inserted.

According to a first aspect of the invention, there is provided a threading device of a sewing machine having a plurality of needles, the threading device being configured to insert a thread through an eye of any one of the needles.

The threading device includes: a threading hook which moves forward to enter the eye of one of the needles and moves backward to catch the thread and to insert the thread through the eye; a threading mechanism which moves the threading hook to insert the thread; a selecting portion operable to select, among the plurality of needles, a needle through which the thread is to be inserted; a positioning mechanism which moves the threading hook to a position corresponding to the needle selected by operating the selecting portion; and a selected needle indicating device which distinguishably indicates the needle with respect to which the threading hook has been positioned by operating the selecting portion.

According to a second aspect of the invention, the selected needle indicating device includes an indicator which moves together with the threading hook, wherein the selected needle indicating device indicates, in accordance with a position of the indicator, the needle with respect to which the threading hook has been positioned.

According to a third aspect of the invention, the selected needle indicating device includes: position detecting means for detecting a position of the threading hook; and display means for indicating the needle corresponding to the position detected by the position detecting means.

According to a fourth aspect of the invention, the selected needle indicating device emits light to indicate the needle with respect to which the threading hook has been positioned.

According to a fifth aspect of the invention, the selected needle indicating device indicates, at a front side portion of the sewing machine, the needle with respect to which the threading hook has been positioned.

According to a sixth aspect of the invention, the selecting portion is disposed on a rear side of an indicating position of the selected needle indicating device.

According to a seventh aspect of the invention, there is provided a threading device of a sewing machine having a plurality of needles arranged along a direction intersecting a cloth feeding direction, the threading device being configured to selectively insert a thread through an eye of one of the needles.

The threading device includes: a threading hook which is supported on a sewing machine arm so as to be rotatable around a vertical axis and movable along an axial direction of the vertical axis, wherein the threading hook is rotatable, at a downwardly moved position which is coincident with the eye of one of the needles, between a forwardly moved position toward which the threading hook enters the eye and a backwardly moved position toward which the threading hook catches and inserts the thread through the eye; a threading mechanism coupled to the threading hook to rotate the threading hook between the backwardly moved position and the forwardly moved position; a selecting portion operable from an outside of the sewing machine to select a needle through which the thread is to be inserted; a positioning mechanism coupled to the threading hook to move the threading hook, interlockingly with the selecting portion, in the direction along which the plurality of needles are arranged to a position corresponding to the selected needle; and a selected needle indicating device including an indicator which is disposed so as to be visible from the outside of the sewing machine, wherein the indicator is configured to interlock with a movement of the threading hook in the direction along which the plurality of needles are arranged.

According to the first aspect of the invention, in a state in which the threading hook is aligned with the corresponding position to the selected needle through the positioning mechanism in accordance with the operation of the selecting portion, the threading hook is rotated and moved forward through the threading mechanism so that the threading operation is executed.

At this time, if the threading hook is aligned in accordance with the operation of the selecting portion, the selected needle indicating device indicates the needle with which the threading hook is aligned so as to be distinguishable from the other needles.

Differently from the case in which the position of the threading hook is visually confirmed, accordingly, it is possible to accurately grasp the selected needle. Furthermore, it is not necessary to operate the threading hook in order to carry out the confirmation before the threading operation. Therefore, it is possible to eliminate a complicatedness of the confirming work.

Also in case of a sewing machine provided with more needles, moreover, it is possible to carry out the confirming work easily and accurately. Consequently, it is possible to properly correspond to a sewing machine having more needles.

“The position corresponding to the needle” is a position of the threading hook at which the threading hook can be inserted into the eye of the needle when the threading hook is moved forward.

According to the second aspect of the invention, the needle with respect to which the threading hook is positioned is indicated in accordance with the change in the position of the indicator which moves together with the threading hook. Therefore, it is not necessary to provide means for detecting the position of the threading shaft and means for displaying information about the position. Consequently, it is possible to confirm the selected needle with a simple structure.

According to the third aspect of the invention, the change in the position of the threading hook is detected and there is provided the display means for indicating the needle based on the detection. Therefore, a mechanical movable structure is not required and a durability can be enhanced without an influence of a deterioration such as an abrasion.

According to the fourth aspect of the invention, the needle with respect to which the threading shaft is positioned is indicated with a light emission. Therefore, the selected needle can be distinguished more accurately and immediately.

According to the fifth aspect of the invention, the needle with respect to which the threading hook is positioned is indicated on the front side portion of the sewing machine. Therefore, the needle to be selected for the execution of the threading work can be confirmed without moving from a place in which the sewing work is to be carried out or changing a posture to look into the place. Consequently, it is possible to enhance a workability of the threading work and to relieve a burden of an operator.

“The front side portion of the sewing machine” is a position to be a front face seen from a position in which the operator is present with respect to the sewing machine in the sewing work, for example, a surface on an upstream side in a feeding direction of a workpiece in a sewing machine frame or a housing cover of the sewing machine.

According to the sixth aspect of the invention, the selecting portion is disposed behind the indicating position of the selected needle indicating device. In the operation for selecting the needle to carry out the threading work, therefore, it is possible to avoid a problem that an arm of the operator to carry out the operation causes the indication of the selected needle positioned on the front side of the sewing machine to be shielded or seen with difficulty. Thus, the selection of the needle can be confirmed well and a selecting error can be avoided, and furthermore, a workability can be enhanced.

“The rear side the indicating position of the selected needle indicating device” implies a provision on a surface positioned at a downstream side in a cloth feeding direction from a surface over which the selection indication is carried out in the sewing machine frame or the housing cover of the sewing machine. Although it is more desirable to set a position to be a rear face seen from a position in which the operator is present with respect to the sewing machine in the sewing work, it is not restricted but an upper or side surface of the sewing machine frame or the housing cover of the sewing machine may be set.

DETAILED DESCRIPTION

Hereinafter, exemplary embodiments of the invention will be explained with reference to the drawings. The following exemplary embodiments do not limit the scope of the invention. In the following description, a Z-axis direction is a vertical direction which is parallel to a needle bar6, an X-axis direction (a first direction) is a direction intersecting a cloth feeding direction, and a Y-axis direction (a second direction) is a direction parallel to the cloth feeding direction.

First Exemplary Embodiment

A threading device10of a sewing machine according to a first exemplary embodiment will be described with reference toFIGS. 1 to 18.

The sewing machine mounting the threading device10thereon can selectively implement an overlock stitch and a cover stitch and has the needle bar6capable of attaching five needles1-5. Two needles1and2are used for the overlock stitch and three needles3,4and5are used for the cover stitch. The needles1,2of a first group and the needles3,4,5of a second group are parallel with the first direction respectively and are disposed with an offset in a second direction.

The threading device10is disposed in an arm portion of the sewing machine adjacently to the needle bar6.

The threading device10includes a threading shaft11for holding a threading hook20to insert, through eyes of the needles1-5, a thread entering the eyes of the needles by a forward movement and caught by a backward movement, a threading mechanism300for giving a back and forth movement to the threading hook20through the threading shaft11, a thread holding member50for holding the thread in an arrangement on an opposite side to the threading hook20with the needles1-5interposed therebetween, a thread holding member support mechanism60for movably supporting the thread holding member50between a threading position in an arrangement on the opposite side to the threading hook20with the needles1-5interposed therebetween and a standby position separated from the needles1-5, a first support mechanism100for supporting the threading shaft11movably in the X-axis direction, a second support mechanism200for supporting the threading shaft11movably in the Y-axis direction, a positioning mechanism400for moving the threading shaft11to a corresponding position to a selected one of the needles1-5by an operation for a selecting dial401(a selecting portion), a selected needle indicating device70for distinguishably indicating one of the needles1-5with respect to which the threading shaft11is positioned through an operation of the selecting dial401, and a main frame90for supporting each structure.

InFIG. 5, a hook holding arm21is fixed to a lower end of the threading shaft11. The threading hook20supported in a tip part of the hook holding arm21has a hook portion formed in a tip part thereof. The hook portion in the tip part of the threading hook20can be inserted into any of eyes1a-5aof the needles1-5in a forward movement through a rotation in one direction of the threading shaft11, and furthermore, is removed from the eye while catching the thread by the hook portion in a return in a reverse direction to the threading shaft11.

A pair of guide plates22,23is provided in parallel in the tip part of the hook holding arm21. The guide plates22,23are provided apart from each other so as to enable an insertion of one of the needles1-5opposite to both sides of the threading hook20. Furthermore, each of the guide plates22,23has a thread guiding notch formed in a slightly lower position than the threading hook20in a direction of extension of the threading hook20. By the guide plates22,23, it is possible to accurately guide any of the eyes of the needles1-5to the threading hook20in a forward movement.

The main frame90of the threading device10is fixed to a frame of an arm portion of the sewing machine which is not shown.

As shown inFIG. 4, the main frame90includes an almost planar back plate91fixed to and supported on the sewing machine frame and a front frame member92bent like a U shape and fixedly coupled to the back plate91. The back plate91holds a main structure of the positioning mechanism400.

The front frame member92has two left and right sidewall portions94and95which are mutually opposed to a rear sidewall portion93provided in cloth contact with the back plate91. The left sidewall portion94on a left side inFIG. 4(a sewing machine face portion side) has a smaller width (a length in the Y-axis direction) than that of the right sidewall portion95.

Moreover, the rear sidewall portion93is set to have a smaller width (the X-axis direction) than that of the back plate91, and the back plate91is greatly protruded leftward with respect to the rear sidewall portion93.

The second support mechanism200is disposed on an inner region of the front frame member92, and the first support mechanism100is disposed on a further inner side thereof.

As shown inFIG. 4, the second support mechanism200includes a second frame member201bent like an almost L shape and supported movably in the Y-axis direction with respect to the front frame member92of the main frame90.

The second frame member201includes a rear sidewall portion203opposed to the rear sidewall portion93of the front frame member92, and a right sidewall portion204opposed to the right sidewall portion95of the front frame member92.

As shown inFIGS. 3 and 4, cylindrical guide shafts202are protruded from upper and lower ends of the right sidewall portion204, and a pair of long slots95ais formed in the Y-axis direction on the right sidewall portion95of the front frame member92opposite to the guide shafts202. Each of the guide shafts202is inserted through each of the slots95aand has C rings205attached to a tip part thereof so that a slip from the slots95acan be prevented.

When each of the guide shafts202is moved along the slot95a, the second frame member201, that is, the whole second support mechanism200can be moved in the Y-axis direction.

Furthermore, a bracket-shaped transmitting arm (an operation transmitting arm)206is protruded rearward from the rear sidewall portion203of the second frame member201and penetrates a horizontal through hole90aprovided on the main frame90and is thus coupled to the positioning mechanism400which will be described below.

As shown inFIG. 4, the first support mechanism100includes a first frame member101supported movably in the X-axis direction with respect to the second frame member201of the second support mechanism200.

The first frame member101includes a rear sidewall portion103opposed to the rear sidewall portion203of the second frame member201, two left and right sidewall portions104,105bent at a right angle from both ends of the rear sidewall portion103and opposed to each other, and a front sidewall portion106bent from one end of the right sidewall portion105and formed along an X-Z plane.

As shown inFIGS. 3 and 4, the rear sidewall portion103is vertically provided with two support brackets107for inserting and supporting the threading shaft11movably in a vertical direction.

Moreover, a cylindrical guide shaft102is protruded from upper and lower ends of the rear sidewall portion103, and a pair of upper and lower slots203afor inserting the respective guide shafts102is formed in the X-axis direction on the rear sidewall portion203of the second frame member opposite to the guide shafts102. Each of the guide shafts102is inserted through each of the slots203aand has a C ring108attached to a tip part thereof, thereby preventing a slip from the slot203a.

The guide shaft102is slid along the slot203aso that the first frame member101can be moved in the X-axis direction. More specifically, the first support mechanism100can be moved in the X-axis direction with respect to the second frame member201so that all the structures supported by the first frame member101can be moved in the X-axis and Y-axis directions with respect to the main frame90in cooperation of the first support mechanism100with the second support mechanism200.

The left sidewall portion104is provided with a bracket109taking an almost U shape seen from a front and a tip part thereof is coupled to the positioning mechanism400which will be described below, and a moving force is transmitted from the bracket109to the first frame member101in the X-axis direction.

Moreover, a boss-shaped engaging projection109bprovided in an upper surface portion of the bracket109is engaged with a forked coupling arm71aprovided in an indicator moving member71of the selected needle indicating device70which will be described below, and has the function of transmitting a moving operation in the X-axis direction of the first frame member101to the indicator moving member71.

As shown inFIGS. 1 and 2, the front sidewall portion106is provided with guide grooves106a,106bfor guiding a movement to a standby position and a threading position of a moving member61in the thread holding member support mechanism60.

The positioning mechanism400will be described with reference toFIGS. 4,6,7,8and9.

The positioning mechanism400has each structure supported mainly on the back plate91of the main frame90.

The positioning mechanism400includes the selecting dial401for sequentially switching the position of the threading shaft11into the needles1-5so as to select one of the needles1-5through which a thread is to be inserted, a stage switching portion410for intermittently dividing a rotating operation of the selecting dial401corresponding to the positions of the respective needles1-5, a first cam mechanism420for giving a moving operation in the X-axis direction to the threading shaft11through the operation of the selecting dial401, and a second cam mechanism430for giving a moving operation in the Y-axis direction to the threading shaft11through the operation of the selecting dial401.

[Selecting Dial and Stage Switching Portion]

As shown inFIGS. 6 and 7, the selecting dial401is fixed to one end of a rotating support shaft422for pivotally supporting a first cam421of the first cam mechanism420.

As shown inFIG. 8, moreover, the stage switching portion410includes a rotor411of the stage switching portion410fixed to the other end of the rotating support shaft422and a leaf spring417having one end fixed to the back plate91.

Engaging concave portions412-416corresponding to the needles1-5respectively are formed on a part of an outer periphery of the rotor411, and the leaf spring417has a tip part provided with a projection capable of being fitted into the engaging concave portions412-416, and always has an elastic force for causing the projection to come in pressure contact with the outer periphery of the rotor411and the projection is fitted into the engaging concave portions412-416to control the rotation of the rotor411.

When the selecting dial401is rotated, therefore, the leaf spring417is moved back and forth to the engaging concave portions412-416by its own elastic force, thereby controlling the rotation into a fitting position, that is, one of the positions corresponding to the needles1-5.

As shown inFIG. 7, the first cam mechanism420includes the rotating support shaft (first rotating support shaft)422supported rotatably with respect to the back plate91in the X-axis direction, the first cam421taking a cylindrical shape which is fixed to the rotating support shaft422and has an almost spiral cam groove421aformed on an outer periphery (which is not shown inFIG. 4), and an oscillating arm423having an intermediate portion423dsupported rotatably around a vertical axis with respect to the back plate91and a projection423ato be a cam follower which is engaged with the cam groove421a.

As shown inFIG. 4, the bracket109of the first support mechanism100has a slot109aformed in the Y-axis direction and an engaging pin423bof the oscillating arm423is inserted into the slot109a. The oscillating arm423is coupled to the bracket109provided on the first frame member101through the engaging pin423bprovided on the other end thereof.

When the first cam421is rotated in a clockwise direction as seen from a left, a moving force is applied in the X-axis direction (a rightward direction) to the follower projection423aof the oscillating arm423. Consequently, the other end of the oscillating arm423generates a leftward movement so that the first frame member101is moved in a leftward direction through the bracket109. When the first cam421is rotated in a reverse direction, moreover, the first frame member101generates a movement in a rightward direction.

The slot109aof the bracket109serves to permit a displacement in the Y-axis direction which is generated in a rotation of the other end of the oscillating arm423, and furthermore, to permit a movement in the Y-axis direction of the first frame member101with a movement in the Y-axis direction of the second frame member201through the second cam mechanism430which will be described below.

The second came mechanism430has a second cam431for oscillating the oscillating arm423and linearly moving the oscillating arm423in the X-axis direction, a rotating support shaft (a second rotating support shaft)432supported rotatably in the X-axis direction with respect to the back plate91, a follower projection433provided on the rotating support shaft432and serving to convert the linear movement of the second cam431into a rotating operation and to transmit the rotating operation to the rotating support shaft432, and an almost L-shaped link member434for applying a moving operation in the Y-axis direction through the operation transmitting arm206to the second frame member201by the rotation of the rotating support shaft432.

The second cam431taking such a shape as to take a part of an outer peripheral surface taking a shape of a hollow cylinder away is supported slidably in the X-axis direction through the rotating support shaft432.

Moreover, the outer peripheral surface of the second cam431is provided with an engaging projection43la which is protruded outward, and the engaging projection431ais inserted into a slot423cformed in a longitudinal direction at one end side of the oscillating arm423. When the oscillating arm423is oscillated by the rotation of the first cam421, the second cam431is moved in the X-axis direction. A detent435shown inFIG. 7controls the movement in the Y-axis direction of the engaging projection431aand the rotation of the second cam431through the insertion of the engaging projection431aof the second cam431into a slot435aformed in the X-axis direction.

Furthermore, the outer peripheral surface of the second cam431is provided with a guide hole431binto which a tip part of the follower projection433is inserted. The guide hole431bhas an almost spiral section (an inclined portion inFIG. 7) formed in an intermediate part thereof. When the follower projection433is engaged with the almost spiral section, it is moved in a circumferential direction to rotate the rotating support shaft432.

A link member434having a lower end supported pivotally on the rotating support shaft432has an upper end coupled to the transmitting arm206extended from the second frame member201. When the link member434is rotated interlockingly with the rotation of the rotating support shaft432, the transmitting arm206is moved in the Y-axis direction so that the second frame member201and the first frame member101which are coupled to the transmitting arm206are moved in the Y-axis direction.

Next, a switching operation in five stages of the selecting dial401will be described with reference toFIG. 9.

(1) A state in which the selecting dial401is adjusted into a position in which the engaging projection of the leaf spring417is fitted in the engaging concave portion412is set to be a first state. At this time, the projection423ais placed in a first position ofFIG. 9Aat one end side of the cam groove421aand the first frame member101is positioned on a rightmost side. Moreover, the follower projection433is placed in a first position ofFIG. 9Bat one end side of the guide hole431band the second frame member201is positioned on a rearmost side. By the arrangement of the first and second frame members101and201, the threading shaft11is placed in a position in which the threading hook20inserts a thread through the needle1.

(2) A state in which the selecting dial401is adjusted into a position in which the engaging projection of the leaf spring417is fitted in the engaging concave portion413is set to be a second state. At this time, the projection423ais placed in a second position ofFIG. 9Ain the cam groove421aand the first frame member101generates a leftward movement. Moreover, the follower projection433is placed in a second position ofFIG. 9Bin the guide hole431band the second frame member201does not generate the movement in the state of (1). In this case, a moving distance of the first frame member101is coincident with an interval in the X-axis direction between the needles1and2. By the arrangement of the first and second frame members101and201, the threading shaft11is placed in a position in which the threading hook20inserts a thread through the needle2.

(3) A state in which the selecting dial401is adjusted into a position in which the engaging projection of the leaf spring417is fitted in the engaging concave portion414is set to be a third state. At this time, the projection423ais placed in a third position ofFIG. 9Ain the cam groove421aand the first frame member101generates the leftward movement. Moreover, the follower projection433is placed in a third position ofFIG. 9Bin the guide hole431band the second frame member201generates a movement toward a front side. In this case, a moving distance of the first frame member101is coincident with an interval in the X-axis direction between the needles2and3and a moving distance of the second frame member201is coincident with an interval in the Y-axis direction between the needles2and3. By the arrangement of the first and second frame members101and201, accordingly, the threading shaft11is placed in a position in which the threading hook20inserts a thread through the needle3.

(4) A state in which the selecting dial401is adjusted into a position in which the engaging projection of the leaf spring417is fitted in the engaging concave portion415is set to be a fourth state. At this time, the projection423ais placed in a fourth position ofFIG. 9Ain the cam groove421aand the first frame member101generates the leftward movement. Moreover, the follower projection433is placed in a fourth position ofFIG. 9Bin the guide hole431band the second frame member201does not generate the movement in the state of (3). In this case, a moving distance of the first frame member101is coincident with an interval in the X-axis direction between the needles3and4. By the arrangement of the first and second frame members101and201, the threading shaft11is placed in a position in which the threading hook20inserts a thread through the needle4.

(5) A state in which the selecting dial401is adjusted into a position in which the engaging projection of the leaf spring417is fitted in the engaging concave portion416is set to be a fifth state. At this time, the projection423ais placed in a fifth position ofFIG. 9Ain the cam groove421aand the first frame member101generates the leftward movement. Moreover, the follower projection433is placed in a fifth position ofFIG. 9Bin the guide hole431band the second frame member201does not generate the movement in the state of (3). In this case, a moving distance of the first frame member101is coincident with an interval in the X-axis direction between the needles4and5. By the arrangement of the first and second frame members101and201, the threading shaft11is placed in a position in which the threading hook20inserts a thread through the needle5.

By carrying out the position switching operation over the selecting dial401from the first state to the fifth state in order as shown in the (1) to (5), it is possible to position the threading shaft11in the position in which the threading hook20can insert the thread into the positions of the needles1-5, thereby carrying out the threading work over them.

The threading mechanism300will be described with reference toFIGS. 2,3and10to14.

The threading mechanism300includes an operation lever310to be operating means for moving the threading shaft11downward and giving a threading operation, a threading slide guide320to be an up-down frame member for carrying out a downward moving operation together with the threading shaft11through a downward operation of the operation lever310, a height regulating mechanism330for blocking the downward movement of the threading shaft11in a plurality of heights corresponding to the heights of the eyes of the needles1-5, and a threading cam mechanism340for rotating the threading shaft11in such a direction that the threading hook20is moved forward when only the threading slide guide320is moved downward with respect to the threading shaft11.

The threading slide guide320includes a back plate321which is vertically long and has an arcuate section, plate-shaped support portions322and323provided integrally with both of upper and lower ends thereof and provided with through holes for inserting the threading shaft11therethrough, and an engaging shaft324with the operation lever310extended leftward in the X-axis direction from the back plate321.

The support portions322and323are plate-shaped along an X-Y plane and are provided with through holes for inserting the threading shaft11therethrough, and the threading slide guide320is coupled to the threading shaft11slidably along the threading shaft11via the through holes. A compression coil spring325is inserted between the upper support portion322and a first guide pin331provided on the threading shaft which will be described below, and a stopper11ato abut on an upper surface of the support portion322is provided on an upper end of the threading shaft11. Therefore, the threading shaft11and the threading slide guide320are always energized in a state in which the threading shaft11is pressed downward and the threading slide guide320is pressed upward.

As shown inFIGS. 3 and 10, the operation lever310is provided on a left side surface of the left sidewall portion94of the main frame90and has a vertical slot311for inserting two guide shafts96protruded leftward in upper and lower positions on a left side surface of the left sidewall portion94, and is held by a C ring97provided in a tip part of each of the guide shafts96so as not to slip off. The operation lever310is supported to be vertically movable with respect to the main frame90by the structure.

The operation lever310includes a long body portion312in a vertical direction, an arm portion313extended in an orthogonal direction (the Y-axis direction) to the body portion312in the vicinity of the middle of the body portion312, and a thread holding member operating portion314bent at a right angle in a tip part of the arm portion313and extended in the X-axis direction.

The slot311is formed to penetrate the body portion312. Moreover, a lower end of the body portion312is bent at a right angle so that a protruded portion315extended in the X-axis direction is formed and a downward pressing operation is carried out therein. Furthermore, the body portion312is coupled to the main frame90through a tension spring316and an upward tensile force is always energized.

On the other hand, a slot317is formed to penetrate the arm portion313in the Y-axis direction and the engaging shaft324extended from the threading slide guide320is inserted therein. Accordingly a downward moving operation applied to the operation lever310is transmitted from the arm portion313to the threading slide guide320and the threading shaft11through the engaging shaft324. The slot317of the arm portion313is provided in the Y-axis direction in order to permit a movement in the Y-axis direction through the second support mechanism200.

The thread holding member operating portion314serves to give an operation for moving the thread holding member50close to the needle side in the forward movement of the threading hook20. The thread holding member operating portion314is provided in the operation lever310to implement an interlocking motion of the forward moving operation of the threading hook20and the close motion of the thread holding member50. An action of the thread holding member operating portion314on the thread holding member50will be described in detail in an explanation of the thread holding member support mechanism60.

The threading cam mechanism340includes an engaging projection341protruded in a horizontal direction from the threading shaft11toward the back plate321of the threading slide guide320and a slot portion342to be a groove cam formed on the back plate321of the threading slide guide320.

The engaging projection341actually serves as a rear end of the first guide pin331provided to penetrate the threading shaft11which will be described below. The engaging projection341is set to have such a length as to be inserted into the slot portion342formed to penetrate the back plate321and to penetrate the back plate321to an outside. The slot portion342is formed with a longitudinal direction inclined to a vertical direction. The engaging projection341is maintained to be usually positioned on a lower end of the slot portion342by an action of the compression coil spring325provided between the threading shaft11and the threading slide guide320. The slot portion342is inclined in such a direction as to generate a displacement in a direction in which the threading shaft11is rotated toward the forward movement of the threading hook20when the engaging projection341is moved upward along the slot portion342. More specifically, the threading shaft11is rotated clockwise as seen on a plane so that the threading hook20is moved forward. Therefore, the slot portion342is inclined upward in such a direction as to be turned toward the rear side in the Y-axis direction.

In the case in which the threading slide guide320is relatively moved downward with respect to the threading shaft11, the engaging projection341is moved upward along the slot portion342. As described above, the threading shaft11and the threading slide guide320are moved vertically until a greater force than a pressing force of the compression coil spring325is applied by the action of the compression coil spring325provided between the threading shaft11and the threading slide guide320and the stopper11aprovided on the upper end of the threading shaft11. Accordingly, the height regulating mechanism330for blocking a downward movement is provided in the middle of a downward moving path of the threading shaft11. When the downward moving operation is applied to the threading slide guide320and the threading shaft11through the operation lever310, the downward movement of only the threading shaft11is blocked in the middle. In this case, when a greater pressing force than the compression coil spring325is applied from the operation lever310, the threading slide guide320is relatively moved downward with respect to the threading shaft11so that the threading shaft11is rotated by the action of the threading cam mechanism340and the threading hook20is moved forward to carry out the threading operation. The threading hook20is moved backward by a return force of the compression coil spring325through the release of the operation lever310.

The height regulating mechanism330has the function of blocking the downward movement of only the threading shaft11in order to operate the threading cam mechanism340and the function of regulating the height of the threading hook20for each of the needles1-5in cooperation with the positioning mechanism400for moving and positioning the threading shaft11corresponding to the arrangement of the needles1-5in the threading operation of the needles1-5.

More specifically, the height regulating mechanism330includes first and second guide pins331,332provided on the threading shaft11, a lower threading guide350having five abutting portions351-355on which either one of the guide pins331,332abuts from above, and an upper threading guide360(which is not shown inFIG. 10) for guiding a revolution of each of the guide pins331,332in the rotation of the threading shaft11.

Both of the first and second guide pins331,332are provided perpendicularly to the threading shaft11, and the first guide pin331is disposed in an upper position. Moreover, the two guide pins331,332are disposed on the threading shaft11at different angles around the threading shaft11over the X-Y plane.

As shown inFIG. 13A, the abutting portion351is disposed in a position in which the first guide pin331is moved downward to abut thereon when the threading shaft11is placed in a position in which the thread is to be inserted through the needle1. As shown inFIG. 13B, the abutting portion352is disposed in a position in which the first guide pin331is moved downward to abut thereon when the threading shaft11is placed in a position in which the thread is to be inserted through the needle2. As shown inFIG. 13C, the abutting portion353is disposed in a position in which the second guide pin332is moved downward to abut thereon when the threading shaft11is placed in a position in which the thread is to be inserted through the needle3. As shown inFIG. 13D, the abutting portion354is disposed in a position in which the second guide pin332is moved downward to abut thereon when the threading shaft11is placed in a position in which the thread is to be inserted through the needle4. As shown inFIG. 13E, the abutting portion355is disposed in a position in which the second guide pin332is moved downward to abut thereon when the threading shaft11is placed in a position in which the thread is to be inserted through the needle5.

Moreover, all of the planes of the abutting portions351-355are formed to have substantially arcuate shapes in such a manner that the guide pins331,332can maintain the abutting state when the threading shaft11abuts to carry out the rotation.

Furthermore, the abutting portions351-355serve to determine the heights of the threading shaft11and the threading hook20in the threading operation respectively. Therefore, respective planar heights are set to be varied depending on the heights of the eyes of the needles1-5.

In addition, the abutting portions351and352and the abutting portions353,354and355are disposed apart from each other depending on opening angles of the guide pins331,332around the threading shaft11respectively. Thus, a plurality of abutting portions is distributed and disposed corresponding to the number of the guide pins to avoid an interference with the arrangement of each of the abutting portions.

Moreover, two guide pins331,332are present. A difference in a height is made between the first guide pin331and the second guide pin332in such a manner that one of the guide pins331,332does not abut on any of the abutting portions when the other abuts on the abutting portion. Furthermore, a relief portion356is formed to be partially lower than an upper surface in such a manner that one of the guide pins does not abut on a portion other than the abutting portion of the lower threading guide350when the other guide pin abuts on the abutting portion (seeFIG. 13A).

The lower threading guide350has the function of determining the height of the threading hook20in the threading operation. For this reason, a height of a certain section is always required. Accordingly, a sewing machine motor is controlled in such a manner that the needle bar is set to have an upper shaft angle in a predetermined certain section to always obtain the same threading enable section in the threading operation.

InFIG. 14, the upper threading guide360has the function of guiding the guide pin in abutment from above so as to maintain an abutment when any of the guide pins331,332abutting on the abutting portions351-355of the lower threading guide350is moved over the upper surfaces of the abutting portions351-355through the rotation of the threading shaft11.

As shown inFIG. 14, accordingly, the upper threading guide360includes a guide portion361for guiding in abutment when the first guide pin331is moved in abutment on the abutting portion351of the lower threading guide350, a guide portion362for guiding in abutment when the first guide pin331is moved in abutment on the abutting portion352, a guide portion363for guiding in abutment when the second guide pin332is moved in abutment on the abutting portion353, a guide portion364for guiding in abutment when the second guide pin332is moved in abutment on the abutting portion354, a guide portion365for guiding in abutment when the second guide pin332is moved in abutment on the abutting portion355, a relief portion366for permitting a downward movement of the first guide pin331in the downward movement of the threading shaft11, and a relief portion367for permitting a downward movement of the second guide pin332in the downward movement of the threading shaft11.

The thread holding portion50is a member formed by bending a plate, and includes two thread guarding portions51,52for guarding a thread at a lower end and an interposing portion53having a leaf spring for interposing the thread end as shown inFIG. 2. The two thread guarding portions51,52have notches for guarding a thread respectively (not shown) and the thread is provided over them and can be thus laid in the X-axis direction. Moreover, the interposing portion53comes in pressure contact with a holding plate and the leaf spring and can interpose the thread end through an insertion therein. Moreover, the interposing portion53is adjacent in a direction in which the two thread guarding portions51,52are provided side by side. The interposing portion53is caused to interpose a residual end of the thread in the case in which the thread guarding operation is carried out with the thread laid over the two thread guarding portions51,52. Consequently, the thread can be maintained to be stretched in the X-axis direction between the two thread guarding portions51,52.

By interposing the thread and disposing the thread holding member50at an opposite side to the threading hook20in a state in which the thread is stretched in the X-axis direction, thus, it is possible to smoothly catch the thread through a return part in a rearward movement when the threading hook20moved forward in the Y-axis direction passes just above the thread which is orthogonal thereto.

[Thread Holding Member Support Mechanism]

As shown inFIGS. 2 and 4, the thread holding member support mechanism60includes the moving member61to be moved by the guide grooves106a,106bof the front sidewall portion106while holding the thread holding portion50oscillatably, an interlocking member62for moving the moving member61downward with the downward movement of the threading shaft11, and an oscillating lever63for oscillating the thread holding portion50placed in a threading position toward the needle side.

The moving member61is a long plate and is disposed in a vertical direction, and guide shafts64are provided in two places in an upper part thereof. The guide shafts64are inserted into the guide grooves106a,106bof the front sidewall portion106respectively and are fixed with a C ring65from a front side. With the structure, the moving member61can carry out a movement along the guide grooves106a,106b. A position of the thread holding portion50in the case in which the moving member61is placed on upper ends of the guide grooves106a,106bis set to be a standby position, and a position of the thread holding portion50in the case in which the moving member61is positioned on lower ends of the guide grooves106a,106bis set to be a threading position.

A boss-shaped projection61bis provided on a rear side of an upper end of the moving member61, and the interlocking member62to carry out an up-down motion together with the threading shaft11abuts thereon from above.

Furthermore, the moving member61includes a plane portion61aobtained by bending a lower part thereof at a right angle and provided along a Y-Z plane, and the thread holding portion50is pivotally supported through a support shaft in the X-axis direction at a lower end of the plane portion61a. Moreover, the oscillating lever63is pivotally supported by the support shaft which is also provided in the X-axis direction in an upper part of the plane portion61a.

The thread holding portion50has the abutting portion54on the oscillating lever63above the support shaft.

On the other hand, the oscillating lever63has the oscillating portion63asuspended downward, and the oscillating portion63ais provided with a projection63b. The projection63babuts on the abutting portion54of the thread holding portion50from a rear side. Moreover, the oscillating lever63is provided, at an upper rear side thereof, with an engagement extending portion63con which the thread holding member operating portion314of the operation lever310abuts from above. When the thread holding member operating portion314of the operation lever310abuts on the engagement extending portion63cfrom above, the oscillating portion63aof the oscillating lever63is oscillated so that the projection63bpresses the abutting portion54of the thread holding portion50toward a front side to oscillate the thread holding portion50. By the oscillation, the thread guarding portions51,52provided at the lower end of the thread holding portion50can approach the needle1to5side to transfer the thread to the threading hook20.

The moving member61of the thread holding member support mechanism60is downward moved interlockingly with the threading shaft11through the interlocking member62. When the threading shaft11is regulated to have a proper height through each of the abutting portions351-355of the lower threading guide350, therefore, the thread holding portion50can also be regulated to have a proper height through the moving member61.

As shown inFIGS. 16 and 17, the selected needle indicating device70includes the indicator moving member71to be moved together with the first frame member101in only the X-axis direction, a panel72(display means) having selection indicating windows72a-72ecorresponding to the respective needles1-5, an indicator73which is coupled to the indicator moving member71and is placed into a position which selectively faces one of the selection indicating windows72a-72efrom a rear side of the panel72, and a slide table74for reciprocably supporting the indicator73in the X-axis direction.

The indicator moving member71has the indicator73fixed to an upper part thereof and is supported movably in the X-axis direction through the slide table74integrally with the indicator73. The indicator moving member71is provided with two coupling arms71aextended in the Y-axis direction. The coupling arms71ahave such a structure that they are extended in parallel with each other in a cantilever state and are engaged with each other to interpose the engaging projection109bprovided on the bracket109of the first frame member101therebetween. An interval between the two coupling arms71ais set to be greater than at least an outside diameter of the engaging projection109b, and the engaging projection109bcan be smoothly moved in the Y-axis direction between the two coupling arms71a.

The first frame member101supports the threading shaft11and carries out a movement in the X-axis direction and the Y-axis direction when the needle to perform the threading operation is to be selected. On the other hand, the indicator moving member71has such a structure that the engaging projection109bis interposed between the two coupling arms71aextended in the Y-axis direction. When the first frame member101is moved, therefore, only the moving operation in the X-axis direction is transmitted to the indicator moving member71.

All of the needles1-5are disposed in different positions in the X-axis direction. When the thread is to be inserted through the needles1-5, therefore, the indicator moving member71is also moved to five fixed positions in the X-axis direction respectively.

The slide table74is fixed to a rear face of a cover12of the sewing machine. A front face portion is provided with a rectangular opening portion74ain the X-axis direction, and the indicator73is fitted in the opening portion74aslidably along the opening portion74a. The opening portion74apenetrates a bottom face side, and the indicator moving member71positioned on the bottom face side and the indicator73can be coupled to each other.

The indicator73has a prismatic bar-shaped portion73aextended in a vertical direction, and a front face of the bar-shaped portion73ais set to have a bright color or a fluorescent color. On the other hand, a front face portion of the slide table74is set to have a black color or a dark color and a contrast is given in such a manner that the bar-shaped portion73aof the indicator73becomes striking.

As shown inFIG. 15, the panel72is fixed to the surface of the cover12of the sewing machine in such a manner that an operator can carry out a visual confirmation from an outside, particularly, a front side of the sewing machine where the operator is placed in the threading work, and is disposed on the front side of the slide table74. The panel72is a square plate and the slit-shaped selection indicating windows72a-72ein the vertical direction are formed in a penetration. The selection indicating windows72a-72eare provided on the level with the bar-shaped portion73aof the indicator73. The selection indicating windows72a-72eare set into the same positions in the X-axis direction as the bar-shaped portion73aof the indicator73when the indicator moving member71is moved to the respective fixed positions in the threading operation for the needles1-5. In other words, when the thread is to be inserted through each of the needles1-5, the bar-shaped portion73aof the indicator73is positioned in one of the five selection indicating windows72a-72ein a one-to-one relationship. In the case in which the bar-shaped portion73aof the indicator73is positioned in one of the selection indicating windows72a-72e, consequently, the bright color or the fluorescent color can be visually recognized through only one of the selection indicating windows and only the black color or dark color of the slide table72can be visually recognized through four other selection indicating windows. By confirming one of the selection indicating windows72a-72ethat has the bright color or the fluorescent color, therefore, it is possible to distinguish the needle selected among the needles1-5.

Moreover, the panel72shows the selected one of the needles1-5on the surface (front side) of the cover12of the sewing machine. Therefore, the operator of the sewing machine is opposed to the panel72so that the indication can be recognized clearly. The surface (front side) of the cover12of the sewing machine indicates a surface at an upstream side in a feeding direction of a workpiece.

As shown inFIG. 15, furthermore, the selecting dial401is protruded leftward from a left side surface of the cover12of the sewing machine and is not present on the same surface as the panel72but is disposed behind the panel72. Therefore, an arm of the operator to manipulate the selecting dial401does not disturb the recognition of the panel72so that the indication can be recognized clearly.

Description will be given to the threading operation of the threading device10having the configuration described above.

First of all, the needles1-5for inserting the thread therethrough are selected by the rotating operation of the selecting dial401.

At this time, the first cam mechanism420moves the first frame member101of the first support mechanism100in the X-axis direction and the second cam mechanism430moves the second frame member201of the second support mechanism200in the Y-axis direction depending on the angular position of the selecting dial401. By their cooperation, the threading shaft11is moved and placed in a predetermined position in the X-Y plane.

At this point, in the height regulating mechanism330, it is determined as to which of the guide pins331,332abut on which of the abutting portions351-355.

When the operation lever310is manipulated downward, then, the threading shaft11starts a downward moving operation together with the threading slide guide320. Moreover, the moving member61is pressed downward by the interlocking member62provided on the upper end of the threading shaft11so that the thread holding portion50also starts the downward moving operation.

When the predetermined guide pins331,332extended from the threading shaft11abut on the predetermined abutting portions351-355, thereafter, the downward moving operation is blocked so that the threading shaft11and the threading hook20are regulated into the height of the selected needle depending on the set height of the abutting portion. Moreover, the thread holding portion50to be interlocked through the interlocking member62is also regulated into the height of the selected height.

At this point, when the operation lever310is further pressed downward, only the threading slide guide320is moved downward with respect to the threading shaft11. As a result, the threading shaft11is rotated clockwise by the action of the threading cam mechanism340. Moreover, the thread holding member operating portion314of the operation lever310presses the oscillating portion63cof the oscillating lever63from above to rotate the oscillating lever63. As a result, the threading hook20is moved forward and is inserted into the eye of the predetermined needle so that the thread holding portion50is tilted toward the needle side to cause the thread stretched in the X-axis direction to approach the front face of the threading hook20. As a result, the return part of the threading hook20catches the thread.

When the operation lever310is released from the downward pressing state, then, the threading hook20starts the backward movement to pull the caught thread into the eye of the needle so that the threading work is executed.

In the case in which the thread is inserted through the other needles, furthermore, the selecting dial401is rotated to downward manipulate the operation lever310again.

Moreover, the operation of the selected needle indicating device70in the case in which the needles1-5for carrying out the threading work are selected by the rotating operation of the selecting dial401will be described with reference toFIG. 18.

When the thread is to be inserted through each of the needles1,2,3,4and5, the first frame member101and the threading shaft11are moved in the X-axis direction and the Y-axis direction through the positioning mechanism400. InFIG. 18, a change in the position of the bracket109with the movement to each position is indicated as1091,1092,1093,1094and1095. When the threading shaft11is aligned with the needles1-5in order, the bracket109is changed into five positions in the X-axis direction and is changed into two positions in the Y-axis direction as shown. However, only a displacement in the X-axis direction is transmitted to the indicator moving member71and the indicator73. The bar-shaped portion73ais positioned in the selection indicating window72awhen the alignment with the needle1is carried out, the bar-shaped portion73ais positioned in the selection indicating window72bwhen the alignment with the needle2is carried out, the bar-shaped portion73ais positioned in the selection indicating window72cwhen the alignment with the needle3is carried out, the bar-shaped portion73ais positioned in the selection indicating window72dwhen the alignment with the needle4is carried out, and the bar-shaped portion73ais positioned in the selection indicating window72ewhen the alignment with the needle5is carried out. Depending on which of the selection indicating windows72a-72eis changed to have the bright color or the fluorescent color, accordingly, it is possible to quickly recognize which of the needles1-5has been selected.

The threading device10supports the threading shaft11to be movable to an optional position on the X-Y plane by means of the first support mechanism100and the second support mechanism200, and the positioning mechanism400selectively carries out a movement and positioning in the five places corresponding to the needles1-5depending on the rotating operation of the selecting dial401in cooperation of the two cam mechanisms420,430.

As in a sewing machine capable of implementing the overlock stitch and the cover stitch by itself, accordingly, also in the case in which the five needles1-5are provided and are not simply arranged in a line, for example, it is possible to position the threading shaft11through only the rotating operation of the selecting dial401without requiring an individual position adjusting operation in a plurality of directions. In addition, it is also possible to carry out the alignment with all of the needles1-5in order. Accordingly, it is possible to precisely insert the thread through all of the needles1-5.

Moreover, the thread holding portion50is provided on the first frame member101through the moving member61. Therefore, the threading shaft11as well as the thread holding portion50can be aligned with all of the needles1-5in order in the X-Y direction through only the rotating operation of the selecting dial401. Furthermore, it is possible to precisely insert the thread through all of the needles1-5.

In addition, in the threading device10, the abutting portions351-355of the lower threading guide350of the threading mechanism300are set to have the heights corresponding to the needles1-5individually. Therefore, it is possible to regulate the threading hook20to have a proper height with respect to the eye of each of the needles1-5.

Also in the case in which the five needles1-5are provided as in the sewing machine capable of implementing the overlock stitch and the cover stitch by itself, two guide pins331,332are provided. Therefore, it is possible to distribute and provide the abutting portions351-355on the lower threading guide350and to properly regulate the height of the threading hook20, thereby causing the threading work to be more appropriate.

Since the selected needle indicating device70is provided, moreover, it is possible to indicate one of the needles1-5with which the threading shaft11is aligned distinguishably from the other needles when carrying out the alignment in accordance with the manipulation of the selecting dial401. Differently from the case in which the position of the threading shaft11is visually confirmed, accordingly, it is possible to accurately grasp the selected needles1-5. Furthermore, it is not necessary to carry out an operation for rotating the threading shaft11in the confirmation. Therefore, it is possible to eliminate the complicatedness of the confirming work.

Moreover, the selected needle indicating device70indicates one of the needles1-5with respect to which the threading shaft11is positioned in accordance with a change in the positions of the indicator moving member71and the indicator73which are moved together with the threading shaft11. Therefore, it is not necessary to provide means for electrically detecting the position of the threading shaft11and means for displaying information about the position and it is possible to confirm the selected needle with a simple structure.

Second Exemplary Embodiment

Although the selecting dial401(the selecting portion) is protruded leftward from the left side surface of the cover12of the sewing machine in the threading device10of the first exemplary embodiment, the present invention is not restricted to such an arrangement. Hereinafter, a second exemplary embodiment in which a selecting portion and an arrangement thereof are different from the first exemplary embodiment will be described with reference toFIGS. 19 to 22. In the second exemplary embodiment, the same structures as those of the threading device10of the first exemplary embodiment have the same reference numerals and description thereof will be omitted.

The second exemplary embodiment is different from the first exemplary embodiment in that, instead of the circular selecting dial401provided on the rotating support shaft422of the first exemplary embodiment, a third rotating support shaft418A is provided above the rotating support shaft422and a selecting lever401A (a selecting portion) is provided on the third rotating support shaft418A as shown inFIG. 19.

More specifically, as shown inFIGS. 20 and 21, the third rotating support shaft418A is supported rotatably by a back plate91in the X-axis direction above the rotating support shaft422at a rear side of the back plate91, and the selecting lever401A is fixed to one end (a left end) thereof.

The selecting operation switching lever401A includes a lever portion401aextended like a bar outward in a radial direction of a disk which is partially cut away linearly, and is fixed to the third rotating support shaft418A in a central position of the disk.

Furthermore, a main driving gear419A is fixed to the other end (a right end) of the third rotating support shaft418A and is engaged with a driven gear424A which is newly provided on the rotating support shaft422. The driven gear424A is fixed to the rotating support shaft422. When a rotating operation is applied to the selecting lever401A, the driven gear424A is rotated through the third rotating support shaft418A and the main driving gear419A, and furthermore, a first cam421is also rotated. Subsequent operations are the same as those of the first exemplary embodiment.

Moreover, the stage switching portion410is moved to an intermediate position between the rotating support shaft422and the third rotating support shaft418A.

By employing the structure, it is possible to dispose the selecting operation switching lever401A rightward and rearward (the rear side) as compared with the selecting dial401and to provide the lever portion401aso as to be protruded from the rear side (the rear side) of the sewing machine cover12as shown inFIG. 22.

Consequently, the selecting lever401A is disposed on a surface at an opposite side to the indicating position of the panel72in the selected needle indicating device70in the cover12. As compared with the selecting dial401, therefore, it is possible to more effectively avoid a problem in that the arm of the operator for executing the operation for selecting the needles1-5to carry out the threading work causes the indication of the selected needle positioned on the front side of the sewing machine to be shielded or seen with difficulty in the same operation, to confirm the selection of the needle more satisfactorily, and to avoid a selection error and to further enhance a workability.

Other Exemplary Embodiments

The selected needle indicating device70may be provided with a sensor for detecting a change in a position for the threading shaft11or a structure to be displaced in the X-axis direction together with the threading shaft11and may be provided with a panel for displaying which of the needles1-5has been selected upon receipt of a signal sent from the sensor. For example, by utilizing a linear scale for detecting a linear moving amount to couple the sensor to the first frame member101in the same structure as the indicator moving member71, it is possible to detect a position of the threading shaft11which corresponds to one of the needles in the X-axis direction. By utilizing a liquid crystal panel to display the needle selected corresponding to a result of the detection, for example, it is possible to quickly recognize the selected needle.

Consequently, it is possible to decrease a mechanical movable structure and to enhance durability without an influence of deterioration such as an abrasion.

Moreover, the selected needle indicating device70may have such a structure that the needle1-5with respect to which the threading shaft11is positioned is indicated with a light emission. For example, it is possible to easily implement the same structure by attaching a light emitting device to the bar-shaped portion73aof the indicator73or utilizing the panel72in the example which is of a light emitting display type.

Consequently, it is possible to distinguish the selected needles1-5more accurately and immediately.

While description has been made in connection with exemplary embodiments of the present invention, those skilled in the art will understand that various changes and modification may be made therein without departing from the present invention. It is aimed, therefore, to cover in the appended claims all such changes and modifications falling within the true spirit and scope of the present invention.