Movable sinker apparatus and sinker of weft knitting machine

There are provided a movable sinker apparatus of a weft knitting machine and a sinker which are capable of holding and pressing down a knitting yarn of a previous loop and sufficiently pulling down a knitting fabric. At forward positions of the sinkers, second protruding portions are close to each other, and thus a knitting fabric can be sandwiched therebetween. When the front and rear needle beds are faced each other so as to be symmetric at the needle bed gap, the forces of the wire springs are applied so as to pull down the knitting fabric in the vertical direction. A knitting yarn receiving portion is formed on a first protruding portion of the front end portion on the sinker, and thus it is possible to retain a knitting yarn of a previous loop and prevent the knitting yarn from moving as the knitting needle moves forward. the second protruding portion that projects outward in a radial direction is formed on a portion close to a front end of the first protruding portion, and the knitting fabric can be sandwiched and pulled down by the second protruding portions provided on the needle beds that are opposed to each other.

PRIORITY STATEMENT

This application is the national phase under 35 U.S.C. § 371 of PCT International Application No. PCT/JP2005/005962 which has an International filing date of Mar. 29, 2005, which designated the United States of America and which claims priority on Japanese Patent Application number P2004-103185 filed Mar. 31, 2004, the entire contents of which are hereby incorporated herein by reference.

TECHNICAL FIELD

The present invention generally relates to a movable sinker apparatus and/or a sinker, of a weft knitting machine. For example, it may relate to one that can press a knitting fabric and pull down the knitting fabric to a lower portion of a needle bed at an appropriate timing during knitting.

BACKGROUND ART

A movable sinker apparatus has been conventionally used that includes, between knitting needles arranged on a needle bed in a weft knitting machine, a sinker displaced by a cam mechanism provided on a carriage such that the sinker is swingingly displaced using as a fulcrum the vicinity on a needle bed gap side of the needle bed, so that the front end portion of the sinker moves forward into the needle bed gap and is withdrawn from the needle bed gap (see Japanese Examined Patent Publication JP-B2 05-83657 (1993), for example). The carriage is provided with a cam for driving the sinkers.

The front end portion of the sinker moves back and forth with respect to the side of the needle bed gap in conjunction with the travel of the carriage, and thus the front end portion can press a knitting fabric, and can be withdrawn from the needle bed gap to prevent, for example, a mechanical contact with other components in the narrow needle bed gap. The force of a spring is also applied to the sinker of the movable sinker apparatus.

When a reaction force from a knitting yarn is greater than the force of the spring, there is room in which the front end portion moves backward from the needle bed gap, and thus too strong a tensile force can be prevented from being applied to the knitting yarn. However, during stitch determination in which the knitting needle is pulled in by a stitch cam, the front end portion of the sinker is regulated so as not to be moved by the cam backward from the needle bed gap. When the carriage moves away, a state is kept in which the front end portion of the sinker has moved forward into the needle bed gap by the force of the spring.

In this movable sinker apparatus, a knitting yarn receiving portion is formed as a recessed portion on the front end side. Thus, when knitting a knitting fabric, it is possible to prevent a knitting yarn of a previous loop from moving together with the knitting needle when the knitting needle moves forward into the needle bed gap, by catching the knitting yarn of the previous loop. It should be noted that a “previous loop” refers to a knitting stitch that is formed by catching a supplied knitting yarn with a hook of the knitting needle and that is still on the knitting needle.

A movable sinker is known that has upper and lower protruding portions (see Japanese Patent No. 2646317, for example). The upper protrusion of a sinker that is disclosed in Japanese Patent No. 2646317 has a function to press a previous loop such that the previous loop does not move upward together with a knitting needle when the knitting needle is moved forward into the needle bed gap.

As shown in descriptions “catching a course in which the knitting material is newly formed” in Paragraph [0010] and “fastening action of the cam 20 on the newest course of the knitting material” in Paragraph [0012], the lower protrusion acts on a previous loop, and has a function as in JP-B2 05-83657.

The movable sinker apparatus of JP-B2 05-83657 is swingingly displaced about a base portion of the sinker, and catches and presses down a knitting stitch of a previous loop with the knitting stitch receiving portion at the front end portion. Also in the configuration of the sinker as disclosed in Japanese Patent No. 2646317, the main function of the lower protrusion is to fasten and press down a knitting stitch of a previous loop as in JP-B2 05-83657.

More specifically, the knitting stitch receiving portion of JP-B2 05-83657 and the lower protrusion of Japanese Patent No. 2646317 prevent a previous loop from moving upward by pressing the previous loop, and also have a function to pull down a knitting fabric. However, a knitting fabric is not sufficiently pulled down depending on knitting conditions, and thus there is a request for a more reliable pulling-down function.

SUMMARY

An object of an embodiment of the invention to provide a movable sinker apparatus and a sinker, of a weft knitting machine, that can retain and press down a knitting yarn of a previous loop and that can sufficiently pull down a knitting fabric.

An embodiment of the invention is directed to a movable sinker apparatus of a weft knitting machine having front and rear needle beds opposed to each other with a needle bed gap interposed therebetween, the movable sinker apparatus comprising:sinkers arranged next to knitting needles, a knitting fabric being knitted by an interaction with knitting needles by applying a force of a spring so as to press down front end portions of the sinkers, and base portions of the sinkers being supported in a swingingly displaceable manner on the needle beds in the vicinity of the needle bed gap, and recessed portions for retaining and pressing down a knitting yarn of a previous loop that has been knitted being formed as knitting yarn receiving portions on front end portions of the sinkers moving forward into the needle bed gap,wherein the front end portion of the sinker has a shape of an arm extending to a lower portion of the needle bed gap in a circumferential direction with a substantially constant radius from the base portion,wherein on a portion closer to the front ends from a knitting yarn receiving portions on the arm are formed protruding portions that project outward in radial directions of swinging displacements,when the protruding portions are on a straight line linking between centers of swinging displacements of the base portions that are supported by the needle beds, the protruding portions of the sinkers are positioned closest toward the needle beds opposed thereto, and inclined faces inclined toward inner sides in the radial direction are respectively formed on the front end side and on the base portion side in the circumferential direction, andwherein the protruding portions of the sinkers provided on the needle beds that are opposed to each other pull down a knitting fabric in a lower portion of the needle bed gap, sandwiching the fabric therebetween.

Furthermore, an embodiment of the invention is directed to a sinker for use in a movable sinker apparatus having a base portion which is supported in a swingingly displaceable manner in a vicinity of a needle bed gap on a needle bed and a front end portion which is moved forward to the needle bed gap to knit a knitting fabric by an interaction with a knitting needle, the sinker comprising:a front end portion having a shape of an arm extending to a lower portion of the needle bed gap in a circumferential direction with a substantially constant radius from the base portion,wherein the sinker is shaped into a plate,wherein on the arm are formed a first protruding portion that is formed between the base portion and the front end and that projects in a circumferential direction on the front end side, and a second protruding portion that is formed on a portion closer to the front end on the arm from the first protruding portion and that projects outward in a radial direction centered on the base portion,wherein on the base portion side in the circumferential direction in the first protruding portion, a knitting stitch forming edge used when a knitting yarn is pulled in with a hook of a knitting needle is formed, andwherein in the second protruding portion, inclined faces inclined toward inner sides in the radial direction are respectively formed on the front end side and on the base portion side on the arm.

DETAILED DESCRIPTION OF THE EXAMPLE EMBODIMENTS

Now referring to the drawings, example embodiments of the invention are described below.

FIG. 1shows the configuration of the main portions of a movable sinker apparatus1of a weft knitting machine according to an embodiment of the invention. The movable sinker apparatus1of a weft knitting machine is provided in a weft knitting machine in which front and rear needle beds are opposed to each other at a needle bed gap2. In the drawing, one needle bed3is shown and the other needle bed is not shown. The needle bed3is inclined with respect to the needle bed gap2such that the needle bed3is high on the needle bed gap side and becomes lower as being away from the needle bed gap. In other words, the front and rear needle beds3are arranged in the shape of V upside down that is centered on the needle bed gap2. However, for the sake of convenience, one needle bed3is shown in a horizontal state. The configuration of one needle bed3is basically similar to the configuration of the other needle bed.

On the needle bed3, a large number of needle plates5are arranged in the direction toward the needle bed gap2, which is an area for knitting a knitting fabric, on a base stage4that is disposed facing the needle bed gap2. The needle plates5are formed such that the plate thickness is thin at the end portions on the needle bed gap2side. Needle grooves6having an increased width on the needle bed gap2side are formed between the needle plates5. Knitting needles7are accommodated in the respective needle grooves6, and sinkers8are accommodated at their respective end portions having an increased width. The needle bed3is thus configured. In the movable sinker apparatus1of a weft knitting machine, the knitting needles7are selectively moved back and forth with respect to the needle bed gap2while letting a carriage travel back and forth on the needle bed3along the needle bed gap2, that is, in the direction perpendicular to the sheet of the drawing, so that a knitting fabric is knitted by an interaction with the sinkers8. In the drawing, the carriage is not shown, and a knitting needle operation cam mechanism9for letting the knitting needles7operate and a sinker operation cam mechanism10for letting the sinkers8operate are shown.

In the needle bed gap2, it is possible to form knitting loops by feeding a knitting yarn from a yarn feeder11to the knitting needle7. The knitting needle7is disposed next to the sinker8in the width direction in each of the needle grooves6, and is a compound needle in which a needle main portion7aand a slider7bcan be independently displaced back and forth with respect to the needle bed gap2. Although the needle main portion7ais provided with a butt for driving a back and forth displacement with respect to the needle bed gap2, the butt is not shown because it is on the left side of the drawing. The slider7bis provided with a butt7cfor driving a back and forth displacement with respect to the needle bed gap2. The needle plate5has, in its end portion on side of the needle bed gap2, a recessed portion5athat supports the sinker8in a swingingly displaceable manner.

The sinker8has a base portion8athat is supported by the recessed portion5a, and a passive portion8bthat is driven following the back and forth displacement with respect to the needle bed gap2. A sinker jack12that can be linearly displaced back and forth with respect to the needle bed gap2is accommodated in each of the needle grooves6. The sinker jack12is provided with an end portion12athat is engaged with the passive portion8bof the sinker8, and has a butt12cthat projects in the direction away from the base stage4of the needle bed3, on a base portion12bside that extends in the direction away from the needle bed gap2with respect to the end portion12a, and a cutout portion12dthat extends in the direction of the back and forth displacement in the middle between the end portion12aand the base portion12b.

A spacer13is disposed in the direction away from the base stage4of the needle bed3with respect to the knitting needle7in each of the needle grooves6, and has the bottom portion regulating the knitting needle7so as not to move away from the base stage4, and the side portion regulating the sinker jack12so as not to be shifted in the width direction of the needle groove6. A metal band15penetrates the spacer13in each of the needle grooves6and the needle plate5, in a direction along the needle bed gap, that is, a direction perpendicular to the sheet of the drawing so that the spacer13and the needle plate5are fixed together by the metal band15. The metal band15is inserted also into the cutout portion12dof the sinker jack12, and functions as a penetrating member for regulating the sinker jack12so as to be slidingly displaced without moving away from the needle groove6.

The sinker8of this embodiment has a front end portion14acting as a sinker with respect to the needle bed gap2, in which a back and forth displacement thereof with respect to the passive portion8bis converted into a swinging displacement using the base portion8aas a fulcrum. A first protruding portion14aand a second protruding portion14bare formed on the front end portion14. A knitting yarn receiving portion14cand a knitting stitch forming edge14dare formed in the first protruding portion14a. Inclined faces14eand14fare formed on both sides in the second protruding portion14b.

The sinker operation cam mechanism10provided on the carriage acts on the butt12cof the sinker jack12to move the sinker jack12backward from the needle bed gap2such that the front end portion14of the sinker8is withdrawn from the needle bed gap2. An interlock mechanism16is provided in order to interlock the sinker jack12in a backward position. In the interlock mechanism16, a wire17interlocks a protrusion12fat the front end of an extending portion12e. The base portion8aof the sinker8is provided with a wire spring18for biasing the sinker8clockwise in the drawing. A wire19is used to fix the needle plates5and the base stage4. At a position close to the needle bed gap2of the bottom portion of the base stage4, is provided a stopper20against which a front end14gof the front end portion14of the sinker8abuts so that the swinging displacement of the sinker8by the force of the wire spring18is regulated.

FIG. 2shows a state in which the sinkers8are in forward positions.FIG. 3shows a state in which when the sinkers8are in the forward positions, the sinkers8have moved by the resisting force from a knitting yarn backward by the amounts of gaps provided at the end portions12aof the sinker jacks12. At forward positions of the sinkers8, the second protruding portions14bof the front end portions14that have moved forward from the front and rear needle beds3into the needle bed gap2are close to each other, and thus a knitting fabric21can be sandwiched therebetween. When the front and rear needle beds3are faced each other so as to be symmetric at the needle bed gap2, the forces of the wire springs18are applied so as to pull down the knitting fabric21in the vertical direction.

The first protruding portion14aof the front end portion14on the sinker8is provided, at a portion close to the front end14g, with the knitting yarn receiving portion14cas a recess inward in the radial direction of a swinging displacement, and thus it is possible to retain a knitting yarn of a previous loop when the knitting needle7moves forward into the needle bed gap2in a knitting operation of a knitting fabric. A portion close to the base portion8aof the first protruding portion14ais provided with the knitting stitch forming edge14d, and thus it is possible to catch a knitting yarn that is supplied from the yarn feeder11when the needle main portion7ais pulled in by the stitch cam of the carriage to determine the stitch density of a knitting stitch formed with the hook of the needle main portion7a.

FIG. 4shows a state in which the sinkers8are in the backward positions. It is possible to reliably press a knitting fabric by moving the sinkers8between the forward positions shown inFIGS. 2 and 3and the backward positions shown inFIG. 4in accordance with the knitting operation of the knitting needles7. In a case where a resisting force that is greater than the force of the wire spring18is received from a knitting yarn when pressing a knitting force, it is possible to relax the tensile force of the knitting yarn by moving the sinker8backward.

FIGS. 2 to 4show that the metal bands15function as guide members for regulating a sliding displacement such that the sinker jacks12do not move away from the needle plates5, by fitting into the cutout portions12dof the sinker jacks12. Furthermore,FIGS. 2 and 3show that in the forward positions, the end portions of the cutout portions12dabut against the side ends of the metal bands15, and thus the metal bands15function also as stoppers.

FIG. 5shows a state in which the sinker jacks12have been moved to the rearmost from the side of the needle bed gap2and the protrusions12fare interlocked with the wires17in the interlock mechanisms16. The sinkers8are in rest positions. On the sinker jacks12, the extending portions12ewhose front ends are provided with the protrusions12ffunction as cantilevers for the base portions12b, and can be elastically deformed when the wires17surmount the protrusions12f. As long as this force causing the elastic deformation is not applied from the outside, the interlock mechanisms16can keep the state in which the sinkers8are in the rest positions.

InFIG. 6, a state in which the sinkers8are in the forward positions is indicated by the solid line, and a state in which the sinkers8are in the backward positions is indicated by the broken line. Furthermore, a straight line22linking between the center positions of swinging displacements of the base portions8aof the sinkers8on the front and rear needle beds3is indicated by the dashed double dotted line. It is preferable that the second protruding portions14bare below the straight line22at the forward positions, and are above the straight line22at the backward positions. In the vicinity of the straight line22, the knitting fabric21is to be sandwiched between the second protruding portions14bof the sinkers8on the front and rear needle beds3. On this straight line, the forces of the wire springs18are applied downward in the vertical direction, and thus it is possible to sufficiently pull down the knitting fabric21.

More specifically, the sinkers8can be displaced by the forces of the wire springs18downward until the front ends14gabut against the stoppers20, and can move upward by the amounts of gaps at the engagement portions between the end portions12aof the sinker jacks12and the passive portions8bof the sinkers8when a reaction force is received, and thus a sufficient effect for pressing and pulling down a knitting stitch of a previous loop is obtained.

In particular, the locus of the second protruding portions14bformed in swinging displacements are in the vertical direction that is perpendicular to the horizontal straight line22linking between the swinging centers of the sinkers8on both needle beds, and thus a pulling-down effect with a sufficient stroke with respect to a knitting fabric is obtained. Furthermore, the inclined faces14eand14fare formed on both sides in the second protruding portions14b, and thus the second protruding portions14bare easily removed from a knitting stitch of the knitting fabric, so that it is possible prevent the knitting fabric from being brought upward when the sinkers8are returned upward.

Accordingly, the movable sinker apparatus1of a weft knitting machine is provided with the sinkers8that are arranged next to the knitting needles7on each of the needle beds3, in a weft knitting machine in which the front and rear needle beds3are opposed to each other with the needle bed gap2interposed therebetween. On the needle beds3in the vicinity of the needle bed gap2in which the knitting fabric21is knitted by moving the knitting needles7forward from the needle beds3, the base portions8aof the sinkers8are supported in a swingingly displaceable manner.

The knitting yarn receiving portions14cthat are recessed portions for retaining and pressing down a knitting yarn of a previous loop are formed at the front end portions14of the sinkers8that move forward into the needle bed gap2. The forces of the wire springs18are applied so as to press down the front end portions14of the sinkers8, and the knitting fabric21is knitted by an interaction with the knitting needles7. The second protruding portions14bthat project outward in the radial directions of swinging displacements from the base portions8aof the sinkers8are formed on a portion closer to the front ends14gfrom the knitting yarn receiving portions14cin the front end portions14of the sinkers8.

The knitting fabric21in a lower portion of the needle bed gap2is sandwiched and pulled down by the second protruding portions14bof the sinkers8provided on the needle beds3that are opposed to each other. Since the fabric21in a lower portion of the needle bed gap2is sandwiched and pulled down by the second protruding portions14bof the sinkers8provided on the needle beds3that are opposed to each other, it is possible to sufficiently pull down the knitting fabric21in a lower portion of the needle bed gap2.

Furthermore, the second protruding portions14bof the sinkers8are positioned closest toward the front and rear needle beds3opposed thereto, when the second protruding portions14bare on the straight line22linking between the centers of swinging displacements of the base portions8athat are supported by the needle beds3, and thus it is possible to sandwich the knitting fabric21from both sides. When the front and rear needle beds3are made symmetric, the straight line22becomes horizontal, and thus the forces applied on the knitting fabric21when the sinkers8are swingingly displaced are directed downward in the vertical direction, so that it is possible to sufficiently pull down the knitting fabric21.

FIG. 7shows the shape of the sinker8excluding the passive portion8b. The sinker8is formed by, for example, punching or cutting a metal plate, and has the base portion8a, the passive portion8bthat is not shown, and the front end portion14. The front end portion14has the shape of an arm that extends to a lower portion of the needle bed gap2in the circumferential direction with a substantially constant radius from the base portion8a. On the arm of the front end portion14are formed the first protruding portion14athat is formed between the base portion8aand the front end14gand that projects in the circumferential direction on the front end side, and the second protruding portion14bthat is formed on a portion closer to the front end14gon the arm from the first protruding portion14aand that projects outwards in the radial direction centered on the base portion8a.

On the inner side in the radial direction in the first protruding portion14a, a recessed portion having the recessed face on the front end14gside is formed as the knitting yarn receiving portion14cthat retains and presses down a knitting yarn of a previous loop of a knitting fabric. On the base portion8aside in the circumferential direction in the first protruding portion14a, a face with a substantially constant radius ra is formed as the knitting stitch forming edge14d. The knitting stitch forming edge14dis pulled into the needle groove on the needle bed3such that the knitting needle7is moved backward with the stitch cam from the needle bed gap2, and thus the stitch density is determined when a knitting stitch is formed with a hook7c. In a knitting stitch that is formed, a portion that was hooked on the knitting stitch forming edge14dis formed as a sinker loop.

The second protruding portion14bis formed so as to project outward in the radial direction from an arc with a radius rb that extends from the knitting stitch receiving portion14ctoward the front end14g. The radius rb is smaller than the radius ra from the first protruding portion14ato the knitting stitch forming edge14cby the width of the knitting yarn receiving portion14c. The front end of the second protruding portion14bprojects outward in the radial direction from the radius rb with respect to the base portion8a. The inclined faces14eand14finclined toward the inner sides in the radial direction are respectively formed on both sides in the circumferential direction in the second protruding portion14b.

The sinker8has the base portion8athat is supported in a swingingly displaceable manner in the vicinity of the needle bed gap2on the needle bed3of a weft knitting machine, and is used in the movable sinker apparatus1of a weft knitting machine in which the front end portion14is moved forward into the needle bed gap2and thus the knitting fabric21is knitted by an interaction with the knitting needle7. The sinker8has the shape of a plate, and the front end portion14has the shape of an arm that extends to a lower portion of the needle bed gap2in the circumferential direction with a substantially constant radius from the base portion8a.

The knitting yarn receiving portion14cand the knitting stitch forming edge14dthat are provided in the first protruding portion14aof the front end portion14of the sinker8knit the knitting fabric21by an interaction with the knitting needle7, and thus it is possible to reliably form a knitting stitch. The knitting fabric21in a lower portion of the needle bed gap2is sandwiched and pulled down by the second protruding portions14bof the sinkers8provided on the needle beds3that are opposed to each other, and thus it is possible to sufficiently pull down the knitting fabric21in the lower portion of the needle bed gap2.

Furthermore, in the second protruding portion14b, the inclined faces14eand14finclined toward the inner sides in the radial direction are respectively formed on the front end14gside on the arm of the front end portion14and on the base end8aside on the sinker8. Even when the second protruding portion14bhas moved into a knitting stitch of the knitting fabric21, with a swinging displacement centered on the base portion8a, it is possible to easily remove the second protruding portion14bfrom the knitting stitch of the sandwiched knitting fabric21.

In particular, even when a knitting fabric is pulled upward and the tensile force is applied while transferring a stitch, since the inclined faces14eand14fare formed, it is easy to remove the second protruding portion14b, and thus it is possible to prevent a yarn from being broken. Furthermore, even when the sinker8is moved backward from the needle bed gap2, it is easy to remove the second protruding portion14bfrom a knitting stitch, and thus it is possible to prevent a knitting fabric from being brought upward.

It is sufficient that the carriage on which the knitting needle operation cam mechanism9and the sinker operation cam mechanism10described above are mounted is provided on each of the front and rear needle beds3, and that the front and rear carriages can move back and forth in the longitudinal direction of the needle beds3in conjunction with each other. It is sufficient that needle selection mechanisms for selecting the knitting needles7that are used for knitting in accordance with knitting data of a knitting fabric are also provided on the carriages. The configuration thereof and the knitting operation by an interaction between the knitting needles7and the sinkers8are similar to those already known, and thus a description thereof has been omitted.

As described above, the front end portion14of the sinker8is provided with the first protruding portion14aand the second protruding portion14b. The function of the second protruding portion14bis not provided in conventional sinkers. On the sinker of JP-B2 05-83657, the knitting yarn receiving portion is formed on the front end side that moves forward into the needle bed gap, and the outer side portion in the radial direction serves as the protruding portion. The protruding portion has a function to prevent a knitting yarn of a previous loop from moving to the needle bed gap as the knitting needle moves forward into the needle bed gap, by catching the knitting yarn of the previous loop. The lower protrusion of Japanese Patent No. 2646317 has a function similar to that of the protruding portion of JP-B2 05-83657.

The function of the first protruding portion14aof this embodiment is the same as those of the protruding portion of JP-B2 05-83657 and the lower protruding portion of Japanese Patent No. 2646317. In JP-B2 05-83657 and Japanese Patent No. 2646317, the protrusions are for catching a knitting yarn of a previous loop thereby preventing the knitting yarn from moving as the knitting needle moves forward into the needle bed gap, and thus the acting position (knitting stitch) is at a previous loop (knitting stitch that is still on the knitting needle), so that knitting stitches on the lower side are not sufficiently taken into consideration. However, the second protruding portion14bof this embodiment acts on the lower side (knitting stitches formed before the previous stitch) of the protruding portions in JP-B2 05-83657 and Japanese Patent No. 2646317.

Accordingly, effects as below are obtained.1. In the case of a coarse knitting fabric, even when the knitting fabric cannot be pressed by the first protruding portion14a, it is possible to press the knitting fabric with the second protruding portion14b(auxiliary role for the first protruding portion14a).2. During knitting, a pulling-down effect of the second protruding portion14bcan be obtained in addition to a pressing-down effect of the first protruding portion14a. Thus, it is not necessary to use an apparatus for pulling down a knitting fabric.3. When knitting of the last course ends and a knitting stitch is released from the knitting needle7, it is possible to reliably drop the knitting fabric by pulling down the knitting fabric with the second protruding portion14bsuch that a dropping failure is not caused by the knitting fabric stuck in the sinkers in a portion on the lower side of the first protruding portion14a. In particular, a knitting fabric is easily stuck when the knitting fabric is thick or tubular, or in the form of gloves or small products having a light self-weight.

It would be appreciated that it is also possible to provide an apparatus for pulling down a knitting fabric in a lower portion of the needle bed gap2in Effects 2 or 3 described above.

INDUSTRIAL APPLICABILITY

According to an embodiment of the invention, base portions of sinkers are supported in a swingingly displaceable manner by needle beds in the vicinity of a needle bed gap in which knitting needles move forward from the needle beds and thus a knitting fabric is knitted. On front end portions of the sinkers moving forward into the needle bed gap, knitting yarn receiving portions are formed that are recessed portions for retaining and pressing down a knitting yarn of a previous loop. When a force of a spring is applied so as to press down the front end portions of the sinkers, a knitting fabric can be knitted by an interaction with the knitting needles.

Protruding portions that project outward in radial directions of swinging displacements are formed on a portion closer to the front ends from the knitting yarn receiving portions in the front end portions of the sinkers. A knitting fabric in a lower portion of the needle bed gap is sandwiched and pulled down by the protruding portions of the sinkers provided on the needle beds that are opposed to each other, and thus it is possible to sufficiently pull down the knitting fabric in the lower portion of the needle bed gap.

Furthermore, the protruding portions of the sinkers are positioned closest toward the needle beds opposed thereto, when the protruding portions are on a straight line linking between the centers of swinging displacements of the base portions of the sinkers that are supported in the vicinity of the needle bed gap on the needle beds, and thus it is possible to sandwich the knitting fabric from both sides. When the front and rear needle beds are made symmetric, the straight line becomes horizontal, and thus the forces applied on the knitting fabric when the sinkers are swingingly displaced are directed downward in the vertical direction, so that it is possible to sufficiently pull down the knitting fabric.

Furthermore, in the protruding portion of the front end portion of the sinker, inclined faces inclined toward inner sides in the radial direction of a swinging displacement centered on the base portion are respectively formed on the front end side and on the base end side on the arm, and thus with a swinging displacement, it is possible to easily remove the second protruding portion from a knitting stitch of a sandwiched knitting fabric. In particular, even when a knitting fabric is pulled upward and the tensile force is applied while transferring a stitch, since the inclined faces are formed, it is easy to remove the second protruding portion, and thus it is possible to prevent a yarn from being broken.

Furthermore, according to an embodiment of the invention, a sinker can be used in a movable sinker apparatus in which its base portion is supported in a swingingly displaceable manner in the vicinity of a needle bed gap on a needle bed of a weft knitting machine and in which its front end portion is moved forward into the needle bed gap and thus a knitting fabric is knitted by an interaction with a knitting needle. The front end portion of the sinker has the shape of an arm that extends to a lower portion of the needle bed gap in a circumferential direction with a substantially constant radius from the base portion. On the arm are formed a first protruding portion that is formed between the base portion and the front end and that projects in the circumferential direction on the front end side, and a second protruding portion that is formed on a portion closer to the front end on the arm from the first protruding portion and that projects outward in a radial direction centered on the base portion.

A knitting yarn receiving portion and a knitting stitch forming edge that are provided in the first protruding portion knit a knitting fabric by an interaction with the knitting needle, and thus it is possible to reliably form a knitting stitch. A knitting fabric in a lower portion of the needle bed gap is sandwiched and pulled down by the second protruding portions of the sinkers provided on the needle beds that are opposed to each other, and thus it is possible to sufficiently pull down the knitting fabric in the lower portion of the needle bed gap.

Furthermore, according to an embodiment of the invention, in the second protruding portion of the front end portion of the sinker, inclined faces inclined toward inner sides in the radial direction of a swinging displacement centered on the base portion are respectively formed on the front end side and on the base end side on the arm, and thus with a swinging displacement, it is possible to easily remove the second protruding portion from a knitting stitch of a sandwiched knitting fabric. In particular, even when a knitting fabric is pulled upward and the tensile force is applied while transferring a stitch, since the inclined faces are formed, it is easy to remove the second protruding portion, and thus it is possible to prevent a yarn from being broken.