Patent Publication Number: US-7216513-B2

Title: Apparatus for applying sliding resistance for weft knitting machine

Description:
TECHNICAL FIELD 
   The present invention relates to an apparatus for applying sliding resistance for a weft knitting machine, which applies sliding resistance to a moving member which is brought by a carriage and slides in a longitudinal direction of a needle bed in a weft knitting machine. 
   BACKGROUND ART 
   Conventionally, in a weft knitting machine, a plurality of knitting needles are disposed adjacent to each other to a needle bed, and knitting of a fabric is executed in a manner that a knitting yarn is fed while a knitting operation is sequentially executed with the knitting needles. The knitting operation sequentially executed with the knitting needles is executed by a cam mechanism for knitting mounted on a carriage moving along the needle bed, and a carrier brought by the carriage feeds the knitting yarn to the knitting needles. 
     FIG. 15  shows a schematic configuration of a mechanism in which a carriage brings a carrier. In a V-bed weft knitting machine in which a pair of needle beds located at the front and back confront at a needle bed gap, a yarn guide rail  1  serving as a guide rail is constructed above the needle bed gap. A bringing pin  3  is caused to appear and disappear in a part where a bridge  2  connecting the carriages disposed to the front and back needle beds crosses the yarn guide rail  1 , thereby being capable of selectively bringing a carrier  4  serving as a moving member capable of traveling along the yarn guide rail  1 . The carrier  4  is provided with a bringing recessed portion  5  with which the projected bringing pin  3  can engage. 
   A yarn feeding position to feed a knitting yarn to the knitting needle while knitting a fabric is set on a way in which the knitting needle is caused to retreat from the needle bed gap after being caused to advance to the needle bed gap by the knitting cam mounted on the carriage. In the case of using the knitting cam in common to move the carriage in one direction and move in the other direction, there is a need to switch the yarn feeding position to a different position with reference to the position of the knitting cam, in accordance with a moving direction of the carriage. In order that a yarn is fed to a position displaced a given distance with respect to the knitting cam in accordance with the moving direction of the carriage, the bringing recessed portion  5  has a specified width. When the carriage reverses the moving direction, a position in which the bringing pin  3  abuts against the bringing recessed portion is switched from one to the other between a right end  5   a  and a left end  5   b  of the bringing recessed portion  5 . 
   When the bringing pin  3  is caused to subside from the side of the carriage that is moving along the knitted fabric, bringing of the carrier  4  by the carriage is stopped, and in a case where the carriage is moving, the carrier  4  persists in moving along the yarn guide rail  1  as well through inertia. However, it is desired that the carrier  4  remain in a position where the bringing has been stopped. This is because in a case where the carrier  4  moves before stopping from the position where engagement of the bringing pin  3  with the bringing recessed portion  5  has been released, the position becomes ambiguous when the carrier  4  is brought next with the bringing pin  3  projected. 
   In order that the carrier  4  having stopped being brought by the carriage is immediately stopped on the yarn guide rail  1 , sliding resistance is applied in-between the carrier  4  and the yarn guide rail  1 . The sliding resistance may be applied mechanically. The sliding resistance may be applied magnetically (for example, refer to Japanese Examined Patent Publication JP-B2 2858768). 
   Since the sliding resistance between the carrier  4  and the yarn guide rail  1  increases a moving load on the carriage when the carriage brings the carrier  4 , it is preferred that the sliding resistance be small. However, there is a possibility that after the bringing stops, a distance necessary for the carrier  4  to stop gets long and a problem like an overrun occurs. The applicant of the present application proposed a technique of, in the case of utilizing magnetism in a weft knitting machine, using a magnetic circuit that includes a permanent magnet and an electromagnet and changing the strength of magnetism by passing pulsed electric current through the electromagnet (for example, refer to Japanese Unexamined Patent Publication JP-A 3-280405 (1991)). 
   In the case of only applying the sliding resistance in-between the carrier and the guide rail as disclosed in JP-B2 2858768, a load on the carriage that is bringing the carrier increases. In the case of mechanically applying the sliding resistance, wear-out is easy to occur as well. Further, when the carriage reverses, a position against which the bringing pin abuts in the bringing recessed portion with which the bringing pin engages changes. 
   For example, in  FIG. 15 , a case where the carriage moves rightward and knitting of one course ends, and the carriage moves leftward in knitting of the next course, will be assumed. While the carriage is moving rightward, the bringing pin  3  abuts against the right end  5   a  of the bringing recessed portion  5 . Even if the carriage stops, the carrier  4  persists in moving more rightward through inertia. In a case where the sliding resistance is small, the carrier  4  continues movement rightward. When the bringing pin  3  is in a projected state, the left end  5   b  of the bringing recessed portion  5  abuts against the bringing pin  3 , and the movement of the carrier  4  stops. When the bringing pin  3  is not projected, there is a possibility that the carrier  4  moves more rightward, that is, an overrun occurs. In a case where the overrun occurs, the bringing recessed portion  5  is away from the bringing pin  3  and cannot bring the carrier  4  even if the bringing pin  3  is projected so as to move the carriage leftward. 
   In a case where the sliding resistance of the carrier  4  to the yarn guide rail  1  is large, it is possible to stop the carrier  4  within a range where the carrier  4  can be brought by the bringing pin  3  at least when the carriage reverses the moving direction. However, since the carrier  4  is brought after the bringing pin  3  abuts against the left end  5   b  of the bringing recessed portion  5 , an impact is generated when the bringing pin  3  abuts against the left end  5   b . This impact gets larder as the sliding resistance of the carrier  4  to the yarn guide rail  1  is larger. It is feared that this impact causes a noise, and that repetition of the impact causes damage. Further, in the case of increasing a moving speed of the carriage in order to increase productivity, an impact and a noise get larger. 
   In the case of using an electromagnet as disclosed in JP-A 3-280405, it is possible to control applied sliding resistance by utilizing magnetism. However, it is difficult to mount a configuration including the electromagnet on the aforementioned carrier  4 . It is desired that the carrier  4  traveling along the yarn guide rail  1  be as small in size and light in weight as possible. Mounting the configuration including the electromagnet on the carrier  4  results in increase of the weight and upsizing. Moreover, it becomes necessary to supply electric power for exciting the electromagnet. 
   DISCLOSURE OF INVENTION 
   An object of the invention is to provide an apparatus for applying sliding resistance for a weft knitting machine, which applies just only a small load on movement of a carriage and can stop promptly and securely when bringing thereof is stopped. 
   The invention is an apparatus for applying sliding resistance for a weft knitting machine, which applies sliding resistance to a moving member which is brought by a carriage and slides in a longitudinal direction of a needle bed in a weft knitting machine, the apparatus comprising: 
   a guide rail disposed in parallel to the longitudinal direction of the needle bed, the moving member being able to slidably move on the guide rail; 
   connection switching means which is capable of carrying out switching between a state where the moving member and the carriage are connected and the carriage brings the moving member, and a state where the connection is released and the carriage does not bring the moving member; 
   first sliding resistance applying means for applying first sliding resistance in-between the guide rail and the moving member; and 
   second sliding resistance applying means for applying second sliding resistance in-between the moving member and the carriage, and making the second sliding resistance smaller than the first sliding resistance at least when the carriage reverses a moving direction. 
   Further, the invention is characterized in that: 
   the first sliding resistance applying means is provided with a first permanent magnet which generates magnetic attraction and applies the first sliding resistance; and 
   the second sliding resistance applying means is provided with a second permanent magnet which generates magnetic attraction and applies the second sliding resistance smaller than the first sliding resistance. 
   Furthermore, the invention is characterized in that: 
   the first sliding resistance applying means is provided with a permanent magnet which generates magnetic attraction and applies the first sliding resistance; and 
   the second sliding resistance applying means is provided with an electromagnet which generates magnetic attraction and applies the second sliding resistance, and which can control the magnetic attraction and make the second sliding resistance smaller than the first sliding resistance at least just before the moving member is brought, by switching of the connection switching means, into a state where it is brought by the carriage. 
   Still further, the invention is characterized in that the second sliding resistance applying means energizes the electromagnet and applies the second sliding resistance when the moving member being brought by the carriage is separated and stopped. 
   Still further, the invention is characterized in that when the moving member is separated, the second sliding resistance applying means excites the electromagnet so as to apply the second sliding resistance, and thereafter, demagnetizes the electromagnet and a magnetically attracting portion of the moving member. 
   Still further, the invention is characterized in that the second sliding resistance applying means excites the electromagnet by passing electric current of one direction therethrough, and demagnetizes by passing demagnetization electric current in a direction opposite to the one direction. 
   Still further, the invention is characterized in that the connection switching means has: 
   a controlling member disposed to one of the carriage and the moving member, being capable of controlling a deformation state; and 
   a bringing member which is disposed to the other of the carriage and the moving member, and has an engagement place for bringing that can engage with the controlling member when the controlling member is in a predetermined deformation state. 
   Still further, the invention is characterized in that the moving member is a holding arm which holds a yarn carrier having a yarn feeding port for feeding a knitting yarn at a tip thereof, in a position where the yarn feeding port faces a knitting needle in knitting operation. 

   
     BRIEF DESCRIPTION OF DRAWINGS 
     Other and further objects, features, and advantages of the invention will be more explicit from the following detailed description taken with reference to the drawings wherein: 
       FIG. 1  is a front view showing a schematic configuration of a weft knitting machine  11  according to an embodiment of the invention; 
       FIG. 2  is a plan view showing a configuration of a part associated with a permanent magnet  23  and an electromagnet  26  of  FIG. 1 ; 
       FIG. 3  is a front view showing a configuration of a part associated with the permanent magnet  23  and the electromagnet  26  of  FIG. 1 ; 
       FIG. 4  is a sectional side view of a needle bed gap  15  and the surrounding area in the weft knitting machine  11  of  FIG. 1 ; 
       FIG. 5  is a graph schematically showing a relationship between control of a moving state of a carriage  13  in the weft knitting machine  11  of  FIG. 1  and electromagnetic brake by energizing the electromagnet  26 ; 
       FIG. 6  is a right side view showing a state in which the carriage  13  has moved to a position of a stopping device  19  that halts a yarn feeder  16  of  FIG. 1 ; 
       FIG. 7  is a partial front view schematically showing a configuration associated with a bringing state switching mechanism  22  and a connecting portion  24  of  FIG. 1 ; 
       FIG. 8  is a front view showing a configuration of the yarn feeder  16  of  FIG. 1 ; 
       FIG. 9  is a front view showing a state in which the yarn feeder  16  of  FIG. 1  is locked into a holder  18 ; 
       FIG. 10  is a front view showing a state in which the yarn feeder  16  of  FIG. 1  is halted by the stopping device  19 ; 
       FIG. 11  is a front view showing another embodiment of a holder  101  that can be placed on a holding arm  21  of  FIG. 1 ; 
       FIG. 12  is a partial front view showing still another embodiment of the invention; 
       FIG. 13  is a graph schematically showing a relationship between control of the moving state of the carriage  13  when the carriage  13  reverses with the holding arm  21  separated and control of an energized state of the electromagnet  26  in still another embodiment of the invention; 
       FIG. 14  is a block diagram showing a schematic electric configuration for executing bipolar driving of the electromagnet  26  in the embodiment of  FIG. 13 ; and 
       FIG. 15  is a partial front view showing a conventional bringing state of a carrier. 
   

   BEST MODE FOR CARRYING OUT THE INVENTION 
   Now referring to the drawings, preferred embodiments of the invention are described below. 
     FIG. 1  shows a schematic configuration of a weft knitting machine  11  as an embodiment of the invention. In the weft knitting machine  11 , a fabric is knitted while a carriage  13  is caused to reciprocate along a needle bed  12 . A pair of needle beds  12  are disposed at the front and back. To each of the needle beds  12 , a number of knitting needles  14  are disposed adjacent to each other, and selectively execute an advancing motion and a retreating motion with respect to a needle bed gap  15  in which the pair of front and back needle beds  12  face each other, under the action of a knitting cam mounted on the carriage  13 . The weft knitting machine  11  is a V-bed weft knitting machine in which the pair of front and back needle beds  12  face across the needle bed gap  15 , and one of a plurality of yarn feeders  16  is selected and brought with the carriage  13 . The yarn feeder  16  is a moving member, and while moving in a constant positional relationship with the carriage  13 , feeds a knitting yarn to the knitting needles  14  and causes them to form stitch loops repeatedly, whereby a fabric can be knitted. It is possible to feed the knitting yarn to the yarn feeders  16  from yarn feeding apparatuses  17 , respectively. 
   In the weft knitting machine  11 , it is possible to selectively hold the plurality of yarn feeders  16  by a plurality of holders  18  disposed on the side of the carriage  13  and cause the carriage  13  to bring, as well as it is possible to halt an unselected yarn feeder  16  in a stopping device  19  disposed at an end portion of the needle bed  12 , for example, at the left end. Moreover, the weft knitting machine  11  is provided with a control unit  20  that causes the carriage  13  to travel and executes selection of the knitting needle  14 , and so on, in accordance with knitting data for knitting a fabric. 
   In the depth direction in the drawing, the plurality of holders  18  are placed on a holding arm  21 . Also, a plurality of stopping devices  19  are arranged to the placement positions of the respective holders  18 . Between the proximal end of the holding arm  21  and the carriage  13 , a bringing state switching mechanism  22  is disposed. A permanent magnet  23  is also disposed to the holding arm  21 . The bringing state switching mechanism  22  is capable of switching a bringing state of the carriage  13  and the holding arm  21 . The bringing state switching mechanism  22  is capable of acting on a connecting portion  24  on the side of the carriage  13 , and shifting a position to bring the holding arm  21  with respect to the carriage  13 , as well as switching to a state not to bring. A guide rail  25  is disposed so that support of the holding arm  21  is kept and the position of the yarn feeder  16  or the like does not change even if the holding arm  21  is separated from the carriage  13 . The guide rail  25  is constructed so as to become parallel to the longitudinal direction of the needle bed  12  along the needle bed gap  15 . 
   The permanent magnet  23  is disposed to a part in which the holding arm  21  is supported by the guide rail  25  and makes sliding displacement in the longitudinal direction, and functions as the first sliding resistance applying means that magnetically applies the first sliding resistance in-between the holding arm  21  serving as the moving member and the guide rail  25 . The carriage  13  is provided with, as the second sliding resistance applying means, an electromagnet  26  that magnetically applies the second sliding resistance in-between the carriage and the holding arm  21 . 
     FIGS. 2 and 3  show a configuration of a part associated with the permanent magnet  23  and the electromagnet  26  of  FIG. 1 .  FIG. 2  shows in top view, and  FIG. 3  shows in front view. The guide rail  25  is formed using a nonferromagnetic metal material, such as aluminum (Al), for the purpose of weight reduction. The electromagnet  26  is formed with a coil  26   a  wound around a yoke  26   b  made of a ferromagnetic material. A metal band  27  made of steel, which is a ferromagnetic metal, is placed on the surface of the guide rail  25 . The metal band  27  is magnetically attracted toward the permanent magnet  23 , and generates the first sliding resistance. It is also possible to form the entire guide rail  25  by using a ferromagnetic metal material, such as steel. 
   The holding arm  21  is formed using a light metal material, such as aluminum, or a synthetic resin material, for the purpose of weight reduction. On the base of the holding arm  21 , together with the permanent magnet  23 , a steel band  28  is also placed. The steel band  28  is disposed in a position to confront the connecting portion  24  of the carriage  13 . A bringing member  29  is disposed to the connecting portion  24  of the carriage  13 , and arranged so as to face the holding arm  21 . The bringing member  29  is provided with a bringing recessed portion  30 . A bringing pin  31  that appears from and disappears to the side of the holding arm  21  can engage with the bringing recessed portion  30 . 
     FIG. 4  shows a configuration in cross section view of the needle bed gap  15  and the surrounding area in the weft knitting machine  11  of  FIG. 1 . Each of the carriages  13  traveling along the longitudinal direction of the front and back needle beds  12  can bring the holding arm  21 , and is provided with the bringing state switching mechanism  22 , the permanent magnet  23 , the connecting portion  24 , the guide rail  25 , the electromagnet  26 , the metal band  27 , the steel band  28 , the bringing member  29  and the bringing pin  31 . To the needle bed gap  15 , not only the tip of the knitting needle  14  advances from each of the needle beds  12 , but also a member used for knitting a fabric, such as a sinker  42 , advances from each of the needle beds  12 . The yarn feeder  16  can be attached to and detached from the holding arm  21  on the upper end side not shown in the drawing. The yarn feeder  16  placed on the holding arm  21  has a yarn feeding port  16   a  at the lower end, and can feed the knitting yarn to the knitting needle  14  that advances to the needle bed gap  15 . 
     FIG. 5  schematically shows a relationship between control of a moving state of the carriage  13  and electromagnetic brake by energizing the electromagnet  26 . Since the carriage  13  reciprocates along the longitudinal direction of the needle bed  12 , an advancing direction is switched between two of rightward and leftward directions alternately. In the control of the moving state of the carriage  13 , an accelerating region in which a speed is increased from a stationary state, a uniform speed region in which the carriage advances at constant speed, and a decelerating region in which the speed is decreased to a stop are provided for each of the advancing directions. A knitting region to execute knitting of a fabric is provided so as to correspond to the uniform speed region in chief. The knitting region may also be set so as to overlap to the accelerating region and the decelerating region. The electromagnetic brake by the electromagnet  26  is made to act at the end of the decelerating region as shown by hatch that slopes to the right. This is for securely stopping the holding arm  21  after the carriage  13  stops. In the accelerating region, the electromagnetic brake is made to act at the beginning. This is for making the second sliding resistance act during a period before the bringing pin  31  abuts against an end portion of the bringing recessed portion  30 . 
     FIG. 6  shows a state where the carriage  13  has moved to a position of the stopping device  19  that halts the yarn feeders  16  in side view. Although a configuration on the side of one needle bed  12  is described more for the convenience of an explanation, there is the same configuration also on the side of the other needle bed  12  with respect to a central face  15   a  of the needle bed gap  15 . Each of the holding arms  21  is capable of holding up to three yarn feeders  16 . However, since the yarn feeding ports  16   a  at the lower ends of the yarn feeders  16  feed the knitting yarn from almost the same positions on the needle bed gap  15 , it is impossible to place the plurality of yarn feeders  16  on the holding arms  21  at the same time. The stopping devices  19  that halt the yarn feeders  16  are arranged with the positions out of line in the longitudinal direction of the needle bed  12 , it is possible to halt the plurality of yarn feeders  16  at the same time in a manner that the yarn feeding ports  16   a  do not interfere with each other. 
   As described above, in the present embodiment, the weft knitting machine  11  comprises, as an apparatus for applying sliding resistance for a weft knitting machine, the guide rail  25 , the bringing state switching mechanism  22  serving as the connection switching means, the permanent magnet  23  serving as the first sliding resistance applying means, and the electromagnet  26  serving as the second sliding resistance applying means, for the purpose of applying sliding resistance to the holding arm  21  serving as the moving member that is brought by the carriage  13  and slides in the longitudinal direction of the needle bed  12 . The guide rail  25  is constructed in parallel to the longitudinal direction of the needle bed  12 , and the holding arm  21  can slide and move thereon. The bringing state switching mechanism  22  is capable of switching to either a state where the holding arm  21  and the carriage  13  are connected and the carriage  13  brings the holding arm  21 , or a state where the connection is released and the carriage  13  does not bring the holding arm  21 . The permanent magnet  23  applies the first sliding resistance in-between the guide rail  25  and the holding arm  21 . The electromagnet  26  applies the second sliding resistance in-between the holding arm  21  and the carriage  13 , and makes the second sliding resistance smaller than the first sliding resistance at least when the carriage  13  reverses a moving direction. When the carriage  13  stops moving, the holding arm  21  persists in moving through inertia. Since the first sliding resistance is applied in-between the holding arm  21  and the stationary guide rail  25 , and the second sliding resistance is applied in-between the holding arm and the carriage  13  that has stopped moving, sliding resistance that is the sum of the first sliding resistance and the second sliding resistance acts on the stationary parts, and it is possible to stop promptly. 
   Since the second sliding resistance does not act when the carriage  13  brings the holding arm  21 , a load on movement of the carriage  13  is only the first sliding resistance of the two sliding resistances, and hence, it is possible to decrease the load. When the carriage  13  starts bringing the holding arm  21 , a direction of the first sliding resistance that acts between the holding arm  21  and the guide rail  25 , and a direction of the second sliding resistance between the carriage  13  having started movement and the holding arm  21  become the opposite, and the holding arm  21  is substantially held back on the guide rail  25  due to a difference between the first sliding resistance and the second sliding resistance, with the result that it is possible to decrease the sliding resistance that acts when bringing is started, and reduce occurrence of an impact and a noise. 
   Further, the holding arm  21  serving as the moving member is provided with the plurality of holders  18 , each of which holds the yarn feeder  16  having the yarn feeding port  16   a  for feeding the knitting yarn at the tip, in a position where the yarn feeding port  16   a  faces the knitting needle  14  in knitting operation, so that the mass is larger than in the case of holding the yarn feeder alone, and inertia at the time of a stop is also large. However, since it is possible to increase the sliding resistance that acts when the holding arm  21  stops at the end of a bringing movement, it is possible to securely stop. Since it is possible to decrease substantial sliding resistance to the guide rail  25  when the carriage  13  converts a direction, it is possible to reduce occurrence of an impact and a noise. 
   That is to say, it is possible to make the second sliding resistance that can be controlled larger than the first sliding resistance, as well as gradually change. For example, when stopping the holding arm  21  serving as the moving member, it is possible to instantly stop by making the second sliding resistance larger than the first sliding resistance. Moreover, it is possible to gradually increase the second sliding resistance when the carriage  13  reverses for reciprocating in the decelerating region, and gradually decrease in the accelerating region, thereby softening an impact at the abutting time when the bringing pin  31  serving as the controlling member and the bringing recessed portion  30  serving as the engagement place for bringing of the bringing member  29  start engaging each other. 
   In the decelerating region, when the carriage  13  stops, it is also possible to control so as to: cause the holding arm  21  serving as the moving member to overrun; and gradually increase the second sliding resistance so that a position of an end portion of the bringing recessed portion  30  against which the bringing pin  31  abuts is switched from the side against which the bringing pin  31  abuts to an end portion on the opposite side before the carriage  13  stops. When the carriage  13  reverses the moving direction and starts movement next, the carriage can start bringing the holding arm  21  in a state where the bringing pin  31  abuts against the end portion of the bringing recessed portion  30  at a speed of 0, so that it is possible to avoid an impact caused by abutting from a state where there is a distance between the bringing pin  31  and the end portion. In a case where there is a distance to the end portion of the bringing recessed portion  30  against which the bringing pin  31  is going to abut, it is possible to avoid occurrence of an impact, by controlling so as to make the second sliding resistance larger than the first sliding resistance and start bringing the holding arm  21  at the beginning of the accelerating region where the carriage  13  starts moving, and decrease the second sliding resistance so that the end portion of the bringing recessed portion  30  gradually abuts against the bringing pin  31  before the knitting region. 
   It is also possible to provide a second permanent magnet which generates magnetic attraction and applies the second sliding resistance smaller than the first sliding resistance, as the second sliding resistance applying means. Since the sliding resistances are applied by the first and second permanent magnets, it is possible to apply the first sliding resistance and the second sliding resistance in a stable manner at all times. Since the second sliding resistance is smaller than the first sliding resistance, when the carriage  13  reverses the moving direction, it is possible to keep the holding arm  21  stationary on the guide rail  25  until bringing by the holding arm  21  starts, and cause only the carriage  13  to move. 
     FIG. 7  schematically shows a configuration associated with the bringing state switching mechanism  22  and the connecting portion  24  of  FIG. 1 . The bringing state switching mechanism  22  is provided with the bringing pin  31  that is a projecting member, a projection amount of which toward the carriage  13  can be changed. The bringing pin  31  is stored in a pin storage hole  33 , and biased by a spring  34  in a direction to project toward the carriage  13  from the pin storage hole  33 . A roller support pin  35  is disposed around a position where the bringing pin  31  is biased by the spring  34 , and a roller  36  is disposed to the tip of the roller support pin  35 . The roller  36  abuts against an operation bar  37 . The operation bar  37  forms a parallelogram link together with a driving link piece  38  and a driven link piece  39  so as to become parallel to the guide rail  25 , and keeps parallel to the longitudinal direction of the needle bed  12 , that is, a direction of the guide rail  25  at all times. The parallelogram link receives a driving force by a motor  40 , and the operation bar  37  can make displacement so as to approach or leave the carriage  13 . 
   The connecting portion  24  on the side of the carriage  13  includes the bringing member  29 . The bringing member  29  is provided with the bringing recessed portion  30  composed of two steps of a deep part  30   a  and a shallow part  30   b . The deep part  30   a  of the bringing recessed portion  30  is for normal knitting, and shorter in length as compared with the shallow part  30   b  for plaiting knitting. In a case where the bringing pin  31  is not allowed to project, the bringing pin  31  does not engage with the connecting member  29 , so that the carriage  13  can move without bringing the holding arm  21 . When the bringing state switching mechanism  22  switches to the state where the holding arm  21  is not brought by the carriage  13 , the carriage  13  can move with the holding arm  21  and the yarn feeder  16  separated therefrom, the mass accompanying the movement is reduced, and a prompt movement becomes possible. 
   That is to say, the bringing state switching mechanism  22 , which serves as the connection switching means, has: the controlling member that is disposed to one of the carriage  13  and the holding arm  21  serving as the moving member, that is the bringing pin  31  capable of appearing and disappearing, and that is capable of controlling a deformation state thereof; and the bringing member  29  that is disposed to the other of the carriage  13  and the holding arm  21 , and that has the bringing recessed portion  30  as the engagement place for bringing that can engage with the bringing pin  31  when the controlling member is in a predetermined deformation state, namely, when the bringing pin  31  is in a projecting state, with the result that when the carriage  13  converts the direction, it is possible to reduce occurrence of an impact and a noise accompanying conversion of a position where the bringing pin  31  and the bringing recessed portion  29  abuts against each other, by decreasing substantial sliding resistance of the holding arm  21  to the guide rail  25 . 
   The controlling member is not limited to the bringing pin  31  capable of appearing and disappearing, and even if the controlling member is a swinging lever or the like, it is possible to achieve a function as the connection switching means, by using a bringing member in which an engagement place for bringing is disposed so as to match. The engagement place for bringing is not limited to a recessed portion like the bringing recessed portion  30 , and even if the engagement place for bringing is a projection, it is also possible to achieve the function. 
     FIG. 8  shows a configuration of the yarn feeder  16  shown in  FIG. 1 . The yarn feeder  16  is provided with a locking mechanism  51  on the proximal end side of a rod-like base  50 , and provided with the yarn feeding port  16   a  on the tip side. The locking mechanism  51  is provided with a pair of levers  53  and  54  and a swing shaft  55 . At the end of the proximal end portion of the base  50 , a guide member  56  is fixed. The guide member  56  is provided with grooves  56   a  and  56   b  on an upper side and a lower side thereof, respectively, and also provided with a recessed portion  56   c  for being locked by the stopping mechanism  11  on an upper portion thereof. 
   The pair of levers  53  and  54  of the locking mechanism  51  intersect at the midpoints so as to be X-shaped, and can make swing displacement about the swing shaft  55  inserted into the intersection, respectively. On one end sides  53   a  and  54   a  of the respective levers  53  and  54 , projections that can be locked into the holder  18  are formed. It is possible to make an external force act on the other end sides  53   b  and  54   b  of the respective levers  53  and  54 . On the other end sides  53   b  and  54   b , grooves  53   a  and  54   c  are formed at portions subjected to application of the external force, respectively. By applying the external force in-between the other end sides  53   b  and  54   b  of the pair of levers  53  and  54 , it is possible to open and close the one end sides  53   a  and  54   a , and switch between a locked state and an unlocked state with respect to the holder  18 . 
   A wire spring  57  is also arranged adjacent to the locking mechanism  51 . The wire spring  57  is made of a material having elasticity, such as piano wire, both ends thereof are guided by projections  58   a  and  59   a  of a pair of swing pieces  58  and  59  disposed on both sides in the width direction of the base  50  and bent portions  50   a  and  50   b  of the base  50 , and a middle portion thereof is curved so that both the ends spring back by using the intersection of the levers  53  and  54  as a fulcrum. Swing fulcrums  58   b  and  59   b  are disposed to the midpoints of the swing pieces  58  and  59 , respectively. The levers  53  and  54  of the locking mechanism  51  are also provided with pressuring portions  53   d  and  54   d  that receive a pressing force from the wire spring  57  between the swing shaft  55  and the other end sides  53   b  and  54   b , respectively. When an external force acts on the other end sides  53   b  and  54   b  of the levers  53  and  54 , the levers  53  and  54  make swing displacement around the swing shaft  55 , the pressuring portions  53   d  and  54   d  of the levers  53  and  54  press the swing pieces  58  and  59 , and the swing pieces  58  and  59  swing on the swing fulcrums  58   b  and  59   b , thereby making the wire spring  57  curved. Since the other end sides  53   b  and  54   b  of the levers  53  and  54  of the locking mechanism  21  serving as locking means are spring-biased by the wire spring  57  serving as biasing means so that the one end sides  53   a  and  53   b  of the levers  53  and  54  approach each other, it is possible to keep the locked state by the spring bias, in the case of letting the one end sides  53   a  and  54   a  of the levers  53  and  54  locked into the holder  18  in the closing direction. 
     FIG. 9  shows a state in which the yarn feeder  16  is locked into the holder  18 . The holder  18  includes an attachment member  60  and a support member  65 . The attachment member  60  has an attachment portion  60   a  for attachment to the holding arm  21  of  FIG. 1 , and a cam groove  60   b  for releasing lock into the recessed portion  56   c  of the guide member  56  of the yarn feeder  16 . The support member  65  has a projected rim  65   a  that fits into the groove  56   b  on the lower side of the guide member  56 , recessed portions  65   b  into which the one end sides  53   a  and  54   a  of the levers  53  and  54  of the yarn feeder  16  are locked, and a pressing portion  65   c  for causing a switching mechanism disposed to the stopping device  19  to operate. The yarn feeder  16  can maintain a state in which the one end sides  53   a  and  54   a  of the pair of levers  53  and  54  of the locking mechanism  51  are locked into the recessed portions  65   b  of the support member  65  of the holder  18 , owing to a bias by a press from the spring wire  57  to pressuring portions  53   d  and  54   d  of the levers  53  and  54 . 
     FIG. 10  shows a state in which the yarn feeder  16  is halted by the stopping device  19 . In the stopping device  19 , from the lower portion of a frame  70  installed upright from the needle bed  12  of  FIG. 1 , a halt control lever  71  is projected along a path where the carriage  13  reaches. The halt control lever  71  can make swing displacement about a swing shaft  72  disposed to the midpoint. One side of the halt control lever  71  across the swing shaft  72  can slidingly contact the other end sides  53   b  and  54   b  of the levers  53  and  54  of the locking mechanism  51  of the yarn feeder  16 , from below. A pressed member  73  is attached on the other side of the halt control lever  71  across the swing shaft  72 . The pressed member  73  is biased by a spring  74  so as to project upward. A bias by the spring  74  also acts on the halt control lever  71  through the pressed member  73 . From the upper portion of the frame  70 , in almost parallel to the halt control lever  71 , a stopping lever  75  projects so as to extend along a traveling path of the carriage  13 . A stopper nail  76  is disposed in the middle of the stopping lever  75 , and a nail portion  76   a  on one end side thereof can be locked into the recessed portion  56   c  of the guide member  56  of the yarn feeder  16 . The stopper nail  76  makes swing displacement by using a swing shaft  76   c  at the midpoint as a fulcrum as a roller  76   b  on the other end thereof is guided in the cam groove  60   b  disposed to the attachment member  60  of the holder  18 , and lock of the yarn feeder  16  by the nail portion  76   a  on the one end side of the stopper nail  76  is released while the holder  18  is passing by the stopping device  19 . 
   A lock piece  78 , an inclination of which is changed by an operation piece  77   a  of a bistable-type solenoid  77 , abuts against the end portion on the other side across the swing shaft  72  of the halt control lever  71 , the pressed member  73  is pressed, the halt control lever  71  presses the other end sides  53   b  and  54   b  of the levers  53  and  54  of the locking mechanism  51  and can be locked in a state where the locking mechanism  51  shifts to the unlocked state. The solenoid  77  can be excited by the control unit  20  of  FIG. 1 . The locked state of the halt control lever  71  can be released by exciting the solenoid  77  in the opposite direction and causing the lock piece  78  to make swing displacement in the opposite direction. 
   In the stopping device  19 , lock by the stopper nail  76  into the yarn-feeder  16  is released by the cam groove  60   b , but it is possible to hinder movement of the yarn feeder  16  by a stopper portion  79  when the pressing portion  65   c  of the holder  18  moves to a position to press the pressed member  73 . 
     FIG. 11  shows another embodiment of a holder  101  that can be placed on the holding arm  21  of  FIG. 1 . A support member  105  of the holder  101  has recessed portions  105   a ,  105   b  and  105   c  at three places, and can selectively lock the yarn feeder  16 . In the case of locking the yarn feeder  16  into the recessed portion  105   b  in the center, it is possible to use for normal knitting in the same manner as the holder  18  of  FIG. 8 . It is possible to use the left and right recessed portions  105   a  and  105   c  disposed to the support member  105 , when displacing a yarn feeding position of the yarn feeder  16  from timing that the knitting needle  14  is caused to advance to the needle bed gap  15  by the knitting cam, and executing inlay knitting, for example. In the case of locking the yarn feeder  16  into the recessed portion  105   a  on the left, it is possible to feed the yarn in advance when the carriage  13  advances to the left. In the case of locking the yarn feeder  16  into the recessed portion  105   c  on the right, it is possible to feed the yarn in advance when the carriage  13  advances to the right. 
     FIG. 12  shows, as another embodiment of the invention, a configuration to apply the first sliding resistance and the second sliding resistance to the carrier  4  moving along the yarn guide rail  1  as shown in  FIG. 15 . In the present embodiment, parts corresponding to those of the prior art of  FIG. 15  and the embodiments shown in  FIGS. 1 to 11  will be denoted by the same reference numerals, and a duplicated description will be omitted. For the purpose of application of the first sliding resistance when the carrier  4  serving as the moving member moves along the yarn guide rail  1  serving as the guide rail, a permanent magnet  113  is disposed. For the purpose of application of the second sliding resistance in-between the bridge  2  linked with the carriage and the carrier  4 , a sliding member  115  is arranged in the bringing recessed portion  5 . When the bringing pin  3  projects and engages with the bringing recessed portion  5 , the tip of the bringing pin  3  slidingly contacts the surface of the sliding member  115 , and sliding resistance by friction is generated. It is possible to regulate the magnitude of the sliding resistance by a pressing force of the bringing pin  3  to the sliding member  115 . It is also possible to dispose this configuration for application of the sliding resistance to the bringing recessed portion  29  shown in  FIG. 2 . Moreover, it is also possible to dispose a permanent magnet and an electromagnet on the side of the bridge  2 , and electromagnetically apply the second sliding resistance. 
     FIG. 13  schematically shows, as still another embodiment of the invention, a relationship between control of the moving state of the carriage  13  when the carriage  13  leaves the holding arm  21  brought thereby and control of the electromagnet  26 . In the present embodiment, a fabric is knitted in the same configuration as in the embodiment of  FIG. 1  basically. In the present embodiment, parts corresponding to those of the embodiment of  FIG. 1  will be denoted by the same reference numerals, and a duplicated description will be omitted. Control executed when the carriage  13  brings the holding arm  21  is the same as in  FIG. 5 . In the present embodiment, when the carriage reverses, the electromagnet  28  is demagnetized as shown by a broken line. Although such a case will be described that the carriage  13  brings the holding arm  21  when moving leftward in the drawing and leaves the holding arm  21  when reversing for movement rightward, it is needless to say that the same control may be executed when the carriage reverses from a rightward movement to a leftward movement. Moreover, it is needless to say that when the carriage  13  brings or leaves the holding arm  21 , the motor  40  is controlled and the bringing state switching mechanism  22  is switched at the same time. 
   In the control shown in  FIG. 5 , in order that the holding arm  21  is prevented from overrunning when the carriage reverses, the control is executed so that the electromagnet  26  is excited and caused to magnetically attract the steel band  28  on the side of the holding arm  21 , and so that the holding arm  21  stops when the carriage  13  stops, and energizing the electromagnet  26  is stopped when the carriage  13  stops. Next, when the carriage  13  is reversed so as to move in the opposite direction, it is expected that the carriage  13  and the holding arm  21  are separated and only the carriage  13  moves unless the electromagnet  26  is energized and excited. However, in the case of separating the holding arm  21  in this way, it is feared that a stop position of the holding arm  21  is not stabilized. The reason is that even if the electromagnet  26  is energized and an attraction force as the second sliding resistance is made to act when the carriage decelerates, and thereafter, energizing the electromagnet  26  is stopped when the carriage reverses, a magnetized state by residual magnetism in the yoke  26   b  of the electromagnet  26  and the steel band  28  is kept, and the attraction force between the carriage  13  and the holding arm  21  does not disappear, with the result that the holding arm  21  is brought when the carriage  13  reverses and moves. In order to appropriately use leaving and bringing of the holding arm  21  by the carriage  13  with security, it is necessary to move the carriage  13  extra in anticipation of a part for the holding arm  21  to be brought back when the carriage  13  reverses. 
   By decreasing the value of electric current for energizing the electromagnet  26  while the carriage  13  is decelerating, it is possible to decrease the residual magnetism after the energizing is stopped, and clear up the bringing back when the carriage reverses. However, the excitation electric current is decreased and the attraction force of the electromagnet  26  to the steel band  28  is also decreased, and it is feared that the holding arm  21  continues movement and overruns after the carriage  13  stops. In a case where the holding arm  21  overruns, in order to bring the holding arm  21  next, it is necessary to move the carriage  13  extra in anticipation of the overrun so as not to fail to bring. 
   In a case where there is an influence of the residual magnetism on attraction by the electromagnet  26 , a stroke of the movement of the carriage  13  must be increased anyway, and a portion of time not to execute knitting in movement of the carriage  13  increases, with the result that productivity is impaired. In order to solve this problem, it is necessary to avoid that the residual magnetism remains in the yoke  26   b  of the electromagnet  26  and the steel band  28 . 
   Then, in the present embodiment, although the electromagnet  26  is energized and caused to attract in the decelerating region of the movement of the carriage  13  in the same manner as in  FIG. 5 , electric current of the opposite direction to the energization electric current is passed when the carriage reverses, whereby the electromagnet  26  is demagnetized and the residual magnetism in the yoke  26   b  and the steel band  28  is eliminated. Consequently, it is possible to secure a sufficient attraction force when attraction is required, eliminate an attraction force by the residual magnetism when separating the carriage  13  and the holding arm  21 , stabilize a stop position of the holding arm  21 , and eliminate a useless stroke from the movement of the carriage  21 . 
   It is possible to demagnetize the electromagnet  26  by passing electric current in the opposite direction to excitation electric current. The timing to pass the electric current of the opposite direction can be either a stage that the carriage  13  stops at the end of the decelerating region of the carriage  13  or the first stage of the accelerating region after the carriage  13  stops and reverses, or can be both. 
   The problem of the residual magnetism is thought to result from the quality of the material of an attracting piece like the steel band  28  and the quality of the material of the yoke  26   b  of the electromagnet  26 . In particular, since the steel band  28  requires wear resistance, a hard material is used. The hard material is commonly, at the same time, a hard magnetic substance on which residual magnetism easily remains. By changing the material of the steel band  28  and the yoke  28   b  to a soft magnetic substance, it is possible to make the residual magnetism hard to remain. However, in the case of a soft magnetic substance, hardness is lower and wear resistance is insufficient. 
   In demagnetization, electric current in the opposite direction to the excitation electric current is passed so as to avoid that a magnetization state continues though holding force H in a demagnetization curve showing a relationship between magnetic flux density B and holding force H of a ferromagnetic substance becomes 0 after excitation. Even if the demagnetization electric current is passed in the opposite direction, there is a possibility that residual magnetism of the opposite direction remains when energization is stopped. By regulating the magnitude of the demagnetization electric current, it is possible to decrease an attraction force by the residual magnetism of the opposite direction, and prevent the carriage  13  from bringing the holding arm  21  back when reversing. In the case of demagnetizing by AC current such that amplitude decreases, it is possible to securely demagnetize. 
     FIG. 14  shows a schematic electric configuration for bipolar driving which makes it possible to excite and demagnetize the electromagnet  26  in the control unit  20  of  FIG. 1 . The control unit  20  includes a controlling portion  120 , an inputting portion  121 , an operating portion  122 , a carriage position detecting portion  123 , and a bipolar driving circuit  124 . The controlling portion  120  is realized including a microcomputer and the like, and executes control necessary for the weft knitting machine  11  to knit. The inputting portion  121  inputs knitting data on a fabric knitted by the weft knitting machine  11 . The operating portion  122  is used when the operator or the like of the weft knitting machine  11  executes a direction operation. The carriage position detecting portion  123  detects whether or not the carriage  13  is in a specific position like the starting position of the needle bed  12 . The bipolar driving circuit  124  is capable of energizing the coil  26   a  of the electromagnet  26  by switching the polarity to execute excitation in one direction and demagnetization in the other direction with DC current. 
   As to the driving of the carriage  13  in the weft knitting machine  11 , the controlling portion  120  can control a carriage moving portion  125  so as to move the carriage  13  along the needle  12 , control a needle selection actuator  125  so as to select the knitting needle  14 , and so on. Moreover, the controlling portion  120  can control the solenoid  77  of the stopping device  19  so as to select whether or not the yarn feeder  16  is brought by the holder  18 . Furthermore, the controlling portion  120  can control the motor  40  so as to change the connection of the holding arm  21  and the carriage  13 . 
   The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description and all changes which come within the meaning and the range of equivalency of the claims are therefore intended to be embraced therein. 
   INDUSTRIAL APPLICABILITY 
   According to the invention, although the moving member persists in moving through inertia when the carriage that is bringing the moving member stops movement, the first sliding resistance is applied in-between the moving member and the stationary guide rail, and the second sliding resistance is applied in-between the moving member and the carriage having stopped moving, so that sliding resistance that is the sum of the first sliding resistance and the second sliding resistance acts on the stationary parts, and it is possible to promptly stop. Since the second sliding resistance does not act when the carriage brings the moving member, it is possible to reduce a load. When the carriage starts bringing the moving member, the moving member is substantially held back on the guide rail due to a difference between the first sliding resistance and the second sliding resistance, and it is possible to decrease sliding resistance that acts when bringing is started, and reduce occurrence of an impact and a noise. 
   Further, according to the invention, it is possible to apply the first sliding resistance and the second sliding resistance with stability at all times. Since the second sliding resistance is smaller than the first sliding resistance, it is possible to move only the carriage while the moving member is stationary on the guide rail until bringing of the moving member is started when the carriage reverses a moving direction. 
   Furthermore, according to the invention, since it is possible to control the second sliding resistance by the electromagnet, it is possible to increase the second sliding resistance and securely stop the moving member, when the carriage stops as well as when the moving member is separated. When the carriage reverses the moving direction, it is possible to make the second sliding resistance slightly smaller than the first sliding resistance, and reduce occurrence of an impact and a noise. Besides, it is possible to make the second sliding resistance that is controllable larger than the first sliding resistance, or gradually change. When separating the moving member from the carriage and stopping, it is possible to make the second sliding resistance larger than the first sliding resistance and instantly stop, thereby preventing an overrun. Additionally, it is possible to gradually increase the second sliding resistance when the carriage reverses for reciprocating in the decelerating region, and gradually decrease in the accelerating region, thereby softening an impact at the abutting time when the controlling member and the bringing member start engaging each other. 
   Still further, according to the invention, since the second sliding resistance applying means excites the electromagnet so as to apply the second sliding resistance at the deceleration stage before the carriage is separated from the moving member, it is possible to generate a sufficient attraction force between the carriage and the moving member, and stop the moving member as the carriage decelerates and stops, by the sliding resistance by the attraction force. 
   Still further, according to the invention, since the residual magnetism exits in a ferromagnetic substance part on which electromagnetic attraction acts even if energizing the electromagnet is stopped, it is possible to demagnetize the electromagnet and a magnetically attracting portion of the moving member, and clear up the residual magnetism. In such a case that the carriage reverses at low speed, the carriage and the moving member are not separated when the residual magnetism exists, and it is feared that the moving member is brought by the carriage when the carriage reverses the moving direction. In a case where excitation electric current to the electromagnet while the carriage is decelerating is decreased so that the residual magnetism becomes small when energizing the electromagnet is stopped, an attraction force between the carriage and the moving member becomes small, and it is feared that the moving member overruns through inertia. In a case where the moving member overruns when the carriage decelerates, the carriage must be moved in anticipation of the overrun in order that the carriage brings the moving member next, a movement stroke of the carriage increases, and a time required for movement of the carriage increases, so that productivity gets lower. Since the second sliding resistance applying means demagnetizes the electromagnet when the carriage reverses, the residual magnetism does not exist in the electromagnet even if the electromagnet is sufficiently excited so as not to cause an overrun, and it is possible to prevent the moving member from being brought undesirably when the carriage reverses. 
   Still further, according to the invention, since the second sliding resistance applying means excites the electromagnet by passing electric current of one direction therethrough, and demagnetizes by passing demagnetization electric current in the opposite direction to the one direction, it is possible to excite and demagnetize by bipolar driving in the one direction and the opposite direction. 
   Still further, according to the invention, it is possible to decrease occurrence of an impact and a noise accompanying conversion of a position where the controlling member and the engagement place for bringing of the bringing member abuts against each other when the carriage converts a direction, by utilizing an overrun by controlling the second sliding resistance at the time of a stop, or by controlling the second sliding resistance when bringing is started. 
   Still further, according to the invention, it is possible to securely a stop the holding arm such that the mass larger than in the case of using the yarn feeder alone and inertia at the time of a stop is also large, by increasing sliding resistance acting at the time of a stop, and decrease occurrence of an impact and a noise by decreasing substantial sliding resistance to the guide rail when the carriage converts a direction.