Patent Publication Number: US-6981393-B2

Title: Yarn feeders of flat knitting machine

Description:
TECHNICAL FIELD 
   The present invention relates to yarn feeders for a flat knitting machine, and more particularly to yarn feeders used to knit an intersia pattern. 
   BACKGROUND ART 
   A fabric having an intersia pattern can be formed by knitting the fabric with different yarns by switching several yarn feeders, when one course is knitted, without separating the fabric. 
   When the fabric having the intarsia pattern is knitted, as shown in  FIG. 11 , plural yarn feeders  12   a  and  12   b  are slidably disposed on a knitting yarn guide rail. The yarn feeder  12   a  feeds yarn to a first knitting region A, the yarn feeder  12   b  feeds yarn to a second knitting region B, and the yarn feeder  12   a  is replaced with the yarn feeder  12   b  at respective yarn changing point. However, when the yarn feeder  12   a  has fed yarn to a leftmost knitting needle of knitting needles for knitting in knitting region A from a right side, the yarn feeder  12   a  has already passed through a point P 1  and is positioned leftward thereof. 
   Accordingly, when the yarn feeder  12   a  is at this position, a problem occurs in that knitting yarn extending in an obliquely lower right direction from the yarn feeder  12   a  is erroneously fed to a knitting needle for knitting in next knitting region B. 
   To eliminate this problem, a yarn feeder disclosed in Japanese Examined Patent Publication No. 61-51061 has been proposed. 
   In the yarn feeder of this publication, of yarn feeders stopped on a knitting yarn guide rail by a brake unit, a yarn feeding port of a yarn feeder selected by a bringing device is first moved from a waiting position to a feeding position approaching knitting needles by sliding the bringing device, and then a braking force is released. 
   When the bringing device subsequently slides, the yarn feeder is brought thereby and feeds yarn to a predetermined knitting needle so that a predetermined region is knitted therewith. Then, the yarn feeder is released from the bringing device and stopped by the brake unit. 
   When the yarn feeder further slides in a state that the yarn feeder is stopped by the brake unit, the yarn feeding port of the yarn feeder is switched from the feeding position to a waiting position that is moved inward of a knitted region from the feeding position to prevent a problem of a knitting needle in an adjacent knitting region being erroneously fed with yarn. 
   In the yarn feeder of this proposal, however, a series of operations for switching the yarn feeding port of the yarn feeder from the waiting position to the feeding position, releasing a braking force, bringing the yarn feeder, and switching the yarn feeding port of the yarn feeder from the feeding position to the waiting position, inward of a knitted fabric region, from the feeding position is executed while the yarn feeder travels from a time before it is brought to a time after it is brought. Accordingly, a sliding distance of the bringing device, which is required to execute the above operations, is increased, and hence a size of the yarn feeder is increased at a portion thereof operated by the bringing device. This problem of an increase in size of the yarn feeder also occurs in a yarn feeder disclosed in, for example, Japanese Examined Patent Application Publication No. 3-23662 and the like. 
   When the size of the yarn feeder is increased, a weight thereof is increased, and a shock, which is generated when, for example, the bringing device brings the yarn feeder at a high speed, is increased, which makes it necessary to reinforce an apparatus in its entirety. 
   An object of the present invention, which was proposed in view of the above problems, is to provide yarn feeders for a flat knitting machine capable of switching a yarn feeding port from a feeding position to a waiting position in a short traveling distance of a bringing device without increasing a size of a portion selected and brought by the bringing device. In a time during which the yarn feeder selected by the bringing means is brought from a stop state, the yarn feeder port is switched from the waiting position outside the knitting area to the feeding position as well as the yarn feeder port after the selection is cancelled is switched to swing toward out side of the knitting area. 
   SUMMARY OF THE INVENTION 
   To achieve the above object, yarn feeders for a flat sewing machine according to the present invention are characterized by being arranged such that feeder case portions are slidably engaged with a knitting yarn guide rail disposed at an upper portion of needle beds and can be selectively brought by a bringing device. Each feeder case is provided with a yarn feeding position and two waiting positions, i.e. a first waiting position and a second waiting position across the yarn feeding position for a yarn feeding port and with a switching mechanism for switching a yarn feeding port to the feeding position and the first and second waiting positions by swinging the yarn feeding port, characterized in that, of the two waiting positions of the yarn feeding port, the waiting position, which is located on an upper side relative to the feeding position of the sliding path of the bringing device along which the bringing device slides for feeding yarn, is set as the second waiting position, the other waiting position located across the feeding position is set as the first waiting position, the switching mechanism switches the yarn feeding port from the first waiting position to the feeding position at a time during which a yarn feeder selected by the bringing means starts to be brought from a stop state, sets a swinging direction such that the yarn feeding port is swung from the feeding position to the second waiting position after it feeds the yarn, and can switch the yarn feeding port from the feeding position to the second waiting position in association with a selection cancel operation of the yarn feeder executed by the bringing device after the yarn is fed. 
   Next, yarn feeders for a flat knitting machine according to the present invention are characterized by being arranged such that feeder rods are swingably and upward/downward movably supported by feeder cases at intermediate portions thereof, yarn feeding ports are formed at lower ends of the feeder rods, swingably operating portions are formed on the intermediate portions of the feeder rods, push-down operation portions for moving yarn feeder portions downward to a feeding position against upward urging forces are formed at upper ends of the feeder rods, setting units for setting a direction in which the swingably operating portions are moved upward and returned are provided, and switching mechanisms are arranged such that when the feeder rods are moved downward to position the yarn feeding ports at a feeding position, the upward-moving and returning direction of the swingably operating portions are switched by the setting units. 
   Further, one of the features of the yarn feeders for a flat knitting machine according to the present invention resides in that the waiting positions of the yarn feeding ports are set on upper sides of the yarn feeding positions in the sliding path of the bringing device along which the bringing device slides for feeding yarn, and the feeding positions are set at positions nearer to the knitting needles than are the waiting positions of the yarn feeding ports. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a side elevational view of a flat knitting machine having a yarn feeding apparatus including yarn feeders of the present invention. 
       FIG. 2  is an enlarged view of a yarn feeding portion of the present invention. 
       FIG. 3  is a view explaining a mechanism of the yarn feeder portion of the present invention. 
       FIG. 4  is an exploded perspective view of the yarn feeder portion of the present invention. 
       FIG. 5  is a view explaining an operation of a selection lever in the yarn feeder of the present invention. 
       FIG. 6  is a view explaining an operation of the selection lever in the yarn feeder of the present invention. 
       FIG. 7  is a view explaining an operation of the selection lever in the yarn feeder of the present invention. 
       FIG. 8  is a view explaining an operation of the selection lever in the yarn feeder of the present invention. 
       FIG. 9  is a front elevational view showing a modification of the selection lever in the yarn feeder of the present invention. 
       FIG. 10  is a front elevational view showing a modification of a push-down mechanism in the yarn feeder of the present invention. 
       FIG. 11  is a view explaining a knitting course in a conventional knitting of an intersia pattern. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   An embodiment of a yarn feeder of a flat knitting machine of the present invention will be explained below based on the drawings. 
     FIG. 1  is a side elevational view of a flat knitting machine having a yarn feeding apparatus including yarn feeders of the present invention, wherein reference numeral  1  denotes the flat knitting machine in its entirety, and  2  denotes the yarn feeding apparatus. 
   The flat knitting machine  1  has a pair of (front and back) needle beds  3  disposed on a frame  4  in a fan shape with extreme ends thereof confronting each other, and each needle bed  3  has plural knitting needles  5  disposed thereon in parallel with each other so that they are movable back and forth. 
   A carriage  6  is disposed on an upper surface of each needle bed  3  so that it can be caused to reciprocatingly travel by a belt drive device (not shown), and the knitting needles  5  are advanced and retreated by a knitting cam  7  attached to the carriages  6 . 
   A gate arm  8  is disposed on the carriages  6  so as to stride over the front and back needle beds  3 , and is integrally coupled with the carriages  6 . Bringing device  10 , which brings yarn feeders  9 , and push-down device  13 , which pushes down weft yarn ports  12  of the yarn feeders  9  to positions near to an extreme end of the knitting needles  5 ,  5 , are mounted on the gate arm  8 . 
   Four knitting yarn guide rails  11  are disposed on an upper portion of the needle beds  3  along a longitudinal direction thereof in a fan shape in a front and back direction of the needle beds  3  near the vicinity of the extreme ends of the knitting needles  5  disposed in parallel with each other on the needle beds  3 . 
   The bringing device  10  is arranged approximately similarly to that disclosed in Japanese Patent No. 3044370. 
   That is, each bringing device  10  includes transmission rods  15  for transmitting movement of output shafts of solenoids, which are projected and retracted in response to a signal output from a controller (not shown), to bringing pins  14  as shown in FIG.  2 . The bringing pins  14  are urged downward by springs  16  so that they bring the yarn feeders  9  by being engaged with engaging portions  19  formed on a pair of right and left swinging pieces  18  disposed on feeder cases  17  of the yarn feeders  9  at portions near centers of upper ends thereof (refer to FIG.  3 ). 
   Each yarn feeder  9  includes feeder case  17  slidably supported by a knitting yarn guide rail  11 , a feeder rod  20  having a yarn feeding port  12  at a lower end thereof, and a feeder rod guide  21  for guiding the feeder rod  20  upwardly and downwardly, with the feeder rod  20  and the feeder rod guide  21  being formed by hanging down from the feeder case  17 . The feeder rod guide  21  is swingably pivoted to the feeder case  17  at a pivot portion located near an upper portion of the feeder rod guide. 
   The feeder rod  20  is formed of a slender sheet-shaped lower plate  22  whose right and left side edge portions are supported by the feeder rod guide  21  so that it is slidably moved upward and downward, an intermediate plate  23  whose lower end portion is coupled with an upper end portion of the lower plate  22 , and an upper plate  25  whose lower end portion is coupled with an upper end portion of the intermediate plate  23  through a push-down roller  24  projecting from an upper back surface of the intermediate plate  23  and being engaged with a lateral slot  26  formed at a lower end portion thereof. 
   Coil springs  27  are mounted in an intermediate portion of the upper plate  25  between it and spring receiving portions  28  of the feeder case  17  in order to urge the yarn feeding port  12  upward through the intermediate plate  23  and the lower plate  22 . 
   Further, a switching roller  30  of a switching mechanism  29 , which switches an attitude of the yarn feeding port  12 , projects from a front surface of the intermediate plate  23  at an upper end portion thereof. 
   The switching mechanism  29  includes the switching roller  30 , a regulation hole  31  formed through the feeder case  17  for regulating a swinging motion of the switching roller  30 , and a selection lever  32  disposed on a back surface side of the regulation hole  31 . 
   As shown in  FIGS. 3 and 4 , the regulation hole  31  is formed in an approximately trifoliate shape having spaces, with which switching roller  30  is engaged, at upper, right, and left portions thereof. 
   The selection lever  32 , which sets an upward moving direction of the switching roller  30  confronting the regulation hole  31 , is formed in an approximately T-shape with its upper end portion  32   a  formed in a gentle V-shape. The selection lever  32  is pivoted to the feeder case  17  at a pivot portion  32   b  at a center as well as lower portion thereof, which hangs down from a central portion of the upper end portion  32   a  and terminates in an arrow shape having inclined surfaces  33  and  34  on right and left sides thereof for directing the upward moving direction of the switching roller  30 . 
   Further, a holding member  36 , which holds two switching attitudes of the selection lever  32 , is disposed at an upper portion of an arrow-shaped portion  35  composed of the two inclined surfaces  33  and  34 . 
   The holding member  36  is arranged such that mustache-shaped elastic portions  37  are extended right and left from an upper portion of the arrow-shaped portion  35 , and wrapping portions  38  and  39  are formed by curving portions near extreme ends of the elastic portions, and engaging projections  40  and  41  are formed on a back surface of the feeder case  17  so that they are engaged with any one of the wrapping portions  38  and  39  when the selection lever  32  is swung right or left. 
   The push-down device  13  for pushing down the feeder rod  20  is composed of a coupling plate  42  whose one end is coupled with the bringing pin  14  at an intermediate height position thereof and a cam plate  43  whose upper end portion is coupled with another end of the coupling plate  42 . With the push-down device  13  arranged as described above, the cam plate  43  is swung back and forth about a swing pivot pin  44  in association with up/down movement of the bringing pin  14 . 
   As shown in  FIG. 3 , the cam plate  43  has a lower side portion formed flat and both ends formed in an inclined state, and the bringing pin  14  is disposed on a knitting yarn guide rail side at a central position of this flat lower side portion. 
   Note that reference numeral  50  in  FIG. 4  denotes a brake unit composed of a magnet attracted to the knitting yarn guide rail. Since the yarn feeder  9  is reduced in size and weight, the yarn feeder  9  can be stopped at an accurate position even by a light sliding friction generated by an attracting force of the magnet. Accordingly, there does not arise such a problem caused in a conventional yarn feeder that when a yarn feeder being brought is to be stopped, it cannot be stopped at a desired position because a stop position of it is made unstable by a large inertia force thereof, and it is not necessary to provide a special brake unit for stopping the yarn feeder at the desired position by overcoming the large inertia force thereof. 
   Next, operation of the yarn feeding apparatus when a fabric is knitted will be described. 
   When the carriages  6  are caused to travel on the needle beds  3 , for example, from right to left (direction shown by an arrow A in  FIGS. 3 and 5 ) by the belt drive device in response to a signal from the controller, the knitting needles  5  disposed in parallel with each other on the needle beds  3  are advanced and retreated by the knitting cams  7 . 
   When the carriages  6  travel, in a portion where no knitting is executed, a solenoid is actuated in response to an output signal for knitting a pattern so that the output shaft of the solenoid is projected downward, thereby the bringing pin  14  of bringing device  10  is moved upward against tension of a spring  16  through a transmission rod  15 . 
   As the bringing pin  14  is moved upward, the cam plate  43  of a push-down device  13  is lifted up about a swing pivot pin  44  (refer to the cam plate  43  on the right side in FIG.  2 ). 
   Then, at a portion where knitting is executed, a solenoid is actuated in response to a signal output from the controller at a position in front of a position where a carriage  6  confronts a predetermined yarn feeder  9  for supplying yarn to knitting needles  5 , and when the output shaft of the solenoid is retreated upward, the bringing pin  14  moved upward heretofore is pushed downward by tension of another spring  16 . In association with this pushed-down operation of the bringing pin  14 , the cam plate  43  of another push-down device  13  is swung toward a yarn feeder side about a swing pivot pin  44  through a coupling plate  42  (refer to the cam plate  43  on the left side of FIG.  2 ). 
   When the carriage  6  slides and the cam plate  43  pushes down the upper end portion  25   a  of an upper plate  25  against an urging force of a coil spring  27 , the switching roller  30  confronting the regulation hole  31  is placed in a state as shown in  FIG. 6  in such a manner that it is guided and lowered to a central lower portion of the regulation hole  31  from the state shown in FIG.  5 . 
   As the switching roller  30  is guided and lowered to the central lower portion of the regulation hole  31 , the feeder rod guide  21  stands upright at a central portion of the feeder case  17  while projecting the yarn feeding port  12  of the feeder rod  20  downward from a lower end of the feeder rod guide  21 , and the yarn feeding port  12  is located at a yarn feed position near the knitting needles  5  on a needle bed  3 . 
   When the carriages  6  further travel leftward and the bringing pin  14  presses a projecting upper end portion  32   a  on a lower part (left side) of the selection lever  32 , the selection lever  32  is swung counterclockwise about the pivot portion  32   b  acting as a center of rotation as shown in FIG.  7 . An attitude of the selection lever  32  is held because the left wrapping portion  38 , which forms a holding member  36 , of the elastic portion  37  of the selection lever  32  is disengaged from engaging projection  40 , and because the right wrapping portion  39  is engaged with engaging projection  41 . 
   Thereafter, when the bringing pin  14  is abutted against the engaging portion  19  of a swinging piece  18  located downstream of an advancing direction of the selection lever  32 , the yarn feeder  9  is brought by the carriage  6 , and yarn is fed to the knitting needles  5  from the yam feeding port  12  of the yarn feeder  9 , whereby a knitting portion is knitted with yarn fed from the yarn feeder  9 . 
   When the knitting portion has been knitted, the solenoid is energized in response to a signal output from the controller, the output shaft of the solenoid is projected downward, and the bringing pin  14  moved downward heretofore is pushed upward against tension of the spring  16 . As the bringing pin  14  is moved upward, the cam plate  43  of the push-down device  13  is swung by being lifted up about the swing pivot pin  44 . 
   When the bringing pin  14  is moved upward and disengaged from the engaging portion  19  of the swinging piece  18  located downward of an advancing direction of the carriage  6 , the yarn feeder  9  is released. In addition, since the cam plate  43  is lifted up and swung, the feeder rod  20  pushed down heretofore is pushed upward by the coil spring  27  to a position where the feeder port  12  at a lower end thereof does not interfere with the yarn feeding port  12  of another yarn feeder  9 , knitting needles  5 , sinkers and the like. 
   When the feeder rod  20  is pushed upward by the coil spring  27 , the selection lever  32  is already switched in a counterclockwise direction. Accordingly, when the switching roller  30  is moved upward, it is moved upwardly left by being guided by the left inclining surface  33  of the selection lever  32  as shown in FIG.  8 . As a result, the yarn feeding port  12  is moved upward in a state that it is swung right together with the feeder rod guide  21 . 
   Next, when the carriage  6  arrives at a predetermined position where knitting yarn is changed, a solenoid is actuated for another yarn feeder  9  to be changed in response to a signal output from the controller similarly to the operation described above, the output shaft of this solenoid is retreated upward, the bringing pin  14  moved upward heretofore is pushed downward by tension of the spring  27  and the cam plate  43  of the push-down device  13  is swung to the yarn feeder side about the swing pivot pin  44 . 
   After the bringing pin  14  is moved downward, fabric is knitted with knitting yarn fed from the yarn feeding port  12  of a yarn feeder  9  selected by the same procedure as that described above. 
   It should be noted that although the above embodiment explains a case that the carriages  6  are caused to travel on the needle beds  3  from right to left by the belt drive device, knitting can be executed similarly when the carriages  6  travel thereon from left to right. 
   Further, in the above embodiment, the holding member  36  is arranged such that the mustache-shaped elastic portions  37  extend from an upper portion of the arrow-shaped portion  35  right and left, the wrapping portions  38  and  39  are formed by curving portions of the elastic portions  37  near extreme ends thereof, and the engaging projections  40  and  41 , which are engaged with any of the wrapping portions  38  and  39  when the selection lever  32  is swung right or left are disposed on the back surface of the feeder case  17 . However, the holding member  36  is not limited to the above arrangement and may be arranged, for example, such that plural recesses or holes  45  are formed at a portion of the selection lever  32  as shown in  FIG. 9 , and a ball or a pin (not shown), which is engaged with the recesses or the holes  45 , is urged on an engagement side by a spring. 
   Further, in the above embodiment, the push-down device  13  is composed of the coupling plate  42  whose one end is coupled with the bringing pin  14  at an intermediate height position thereof and the cam plate  43  whose upper end portion is coupled with another end portion of the coupling plate  42 , and the cam plate  43  is swung back and forth about the swing pivot pin  44  in association with upward/downward movement of the bringing pin  14 . However, the push-down device  13  may be altered as shown in, for example, FIG.  10 . 
   That is, a receiving piece  46 , which is formed by upsetting the cam plate  43  of the above embodiment, is disposed at an upper end portion of the feeder rod as well, and a receiving piece is pushed downward and the selection lever  32  is switched by traveling about the bringing pin  14 . 
   INDUSTRIAL APPLICABILITY 
   As described above, in the yarn feeders for the flat knitting machine according to the present invention have feeder case portions, which are slidably engaged with a knitting yarn guide rail disposed at an upper portion of needle beds and can be selectively brought by a bringing device, and the feeder cases each of which is provided with a switching mechanism for switching yarn feeding ports between a feeding position and a waiting position, wherein the switching mechanism has the yarn feeding port and the two waiting positions, i.e. a first waiting position and a second waiting position located across the yarn feeding port, the switching mechanism is operated at a time during which a yarn feeder selected by the bringing device is brought from a stop state in order to feed yarn, the yarn feeding port is switched from the first waiting position to the yarn feeding position, the swinging direction, in which the yarn feeding port is swung to the second waiting position after it feeds the yarn, is set, and the yarn feeding port can be switched from the feeding position to the second waiting position in association with a selection cancel operation of the bringing device after it feeds the yarn. 
   With the above arrangement, a sliding distance of the bringing device, which is required to execute a series of operations for switching the yarn feeding port of the yarn feeder from the waiting position to the feeding position, bringing the yarn feeder, and switching the yarn feeder port of the yarn feeder from the feeding position to the waiting position inward of a knitted fabric region knitted, can be shortened, and hence an increase in size of portions of the yarn feeders actuated by the bringing device can be prevented. 
   Since an increase in size of the yarn feeders can be prevented, an increase in weight of the yarn feeders can also be prevented. As a result, there can be also obtained advantages in that even if the bringing device brings the yarn feeders at a high speed, a shock caused in this process can be reduced, thereby the apparatus need not be reinforced in its entirety and durability of the apparatus can be improved.