(19)
(11)EP 3 608 462 A1

(12)EUROPEAN PATENT APPLICATION

(43)Date of publication:
12.02.2020 Bulletin 2020/07

(21)Application number: 19190078.6

(22)Date of filing:  05.08.2019
(51)Int. Cl.: 
D04B 15/10  (2006.01)
D04B 15/18  (2006.01)
D04B 15/14  (2006.01)
(84)Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR
Designated Extension States:
BA ME
Designated Validation States:
KH MA MD TN

(30)Priority: 10.08.2018 JP 2018151758

(71)Applicant: Precision Fukuhara Works, Ltd.
Kobe-shi Hyogo 651-2242 (JP)

(72)Inventors:
  • NISHIGAKI, Masato
    Nishi-ku, Kobe-shi, Hyogo 651-2242 (JP)
  • ENISHI, Masaru
    Nishi-ku, Kobe-shi, Hyogo 651-2242 (JP)

(74)Representative: Dr. Gassner & Partner mbB 
Wetterkreuz 3
91058 Erlangen
91058 Erlangen (DE)

  


(54)NEEDLE BED FOR CIRCULAR KNITTING MACHINE, AND CIRCULAR KNITTING MACHINE INCLUDING SAME NEEDLE BED


(57) To provide a needle bed for a circular knitting machine in which, an insert piece for forming a groove for slidably storing the knitting tool, the contact area between the knitting tool and the insert piece is reduced. A needle bed which is mountable to the circular knitting machine is configured to slidably store a knitting tool in a groove of which both side surfaces are formed by opposed plate surfaces of adjacent insert pieces 50 having a rectangular plate shape, wherein each insert piece 50 has a plurality of dimples 53 formed in a short-side direction X and a long-side direction Y on the plate surfaces.




Description

BACKGROUND OF THE INVENTION


(Field of the Invention)



[0001] The present invention relates to a needle bed that stores a knitting tool, and a circular knitting machine that rotates the needle bed to knit a tubular knitted fabric.

(Description of Related Art)



[0002] Conventionally, there is known a circular knitting machine that rotates a needle cylinder having a plurality of needles slidably stored in needle grooves, to knit a tubular knitted fabric. Of such circular knitting machines, a single-knit circular knitting machine and a double-knit circular knitting machine are widely used. In the single-knit circular knitting machine, cylinder needles and sinkers are provided to a rotatable needle cylinder. In the double-knit circular knitting machine, needles are provided to both a rotatable needle cylinder and a needle dial.

[0003] The single-knit circular knitting machine includes a cylindrical needle cylinder. A sinker dial is disposed to an upper part of the needle cylinder, and the needle cylinder and the sinker dial rotate synchronously with each other. The cylinder needles are inserted into needle grooves formed vertically on the outer circumference of the needle cylinder. When the needle cylinder is rotated by driving the circular knitting machine, the cylinder needles perform up-and-down movements vertically along cam races. Sinkers for assisting loop formation are inserted into sinker grooves formed radially on the upper surface of the sinker dial. When the sinker dial is rotated by driving the circular knitting machine, the sinkers perform back-and-forth movements horizontally along cam races. The cylinder needle and the sinker are disposed perpendicularly with each other, and form a loop of a knitted fabric by their mutual movements.

[0004] The double-knit circular knitting machine includes a disk-shaped needle dial and a cylindrical needle cylinder. The needle dial is disposed to an upper part of the needle cylinder, and the needle dial and the needle cylinder rotate synchronously with each other. The cylinder needles are inserted into needle grooves formed vertically on the outer circumference of the needle cylinder. When the needle cylinder is rotated by driving the circular knitting machine, the cylinder needles perform up-and-down movements along cam races. Dial needles are inserted into needle grooves formed radially on the upper surface of the needle dial. When the needle dial is rotated by driving the circular knitting machine, the dial needles perform back-and-forth movements horizontally along cam races. The cylinder needle and the dial needle are disposed perpendicularly with each other, and form a loop of a knitted fabric by their mutual movements.

[0005] In general, a needle bed refers to a part that stores knitting tools such as cylinder needles, sinkers, and dial needles as described above and jacks of a needle selection device, which are moved during operation of the circular knitting machine while being guided by cams, the needle selection device, or the like. The single-knit circular knitting machine has needle beds such as a needle cylinder and a sinker dial for storing cylinder needles, sinkers, jacks, and the like. The double-knit circular knitting machine has needle beds such as a needle cylinder for storing cylinder needles, jacks, and the like, and a needle dial for storing dial needles, jacks, and the like.

[0006] Examples of needle beds include a needle bed manufactured by processing a base material so as to form grooves each having both side surfaces and a bottom surface for movably storing a knitting tool such as a sinker, and a needle bed manufactured by forming insert piece grooves, and then inserting insert pieces into the grooves and applying an adhesive agent to joining portions, or fitting insert pieces into the grooves. The needle bed provided with the insert pieces slidably stores knitting tools such as needles and jacks in grooves of which both side surfaces are formed by the adjacent insert pieces and a bottom surface is formed by the base material.

[0007] During operation of the circular knitting machine, for example, in the needle cylinder, the cylinder needle slides between the insert pieces, so that a frictional force is generated between the cylinder needle and each insert piece. Due to deterioration by friction, the durable periods of both parts might be shortened. Therefore, it is necessary to reduce the frictional force. In addition, for example, also in the sinker dial, the sinker which is a knitting tool slides between the side surfaces of the groove formed in the needle bed. Therefore, similarly, it is necessary to reduce the frictional force between both parts.

[0008] As conventional technology for reducing the frictional force by reducing the contact area between the insert piece and the needle, the following examples are known. In Japanese Laid-open Utility Model Publication No. S48-089948, the sectional shape of an insert piece is designed to be a wavy shape. In Chinese Patent Publication No. 101805955, an insert piece is embossed to have a great recess in a row in the long-side direction or a great through hole or the like is formed in an insert piece. In US Patent No. 1869416, a wavy shape or a through hole in an insert piece as described above is formed by press working using a die.

[0009] However, the shapes of the plate surfaces of the conventional insert pieces require significant changes in the structures of the insert pieces, thus taking time and cost for processing. Further, fine accuracy is required in the circular knitting machine. In the case where an insert piece and a knitting tool are processed so as to be bent in a wavy shape or to have a great hole or recess, it is difficult to locate, in the same plane, all the contact points between the insert piece and the knitting tool. Therefore, the dimension accuracy of the processing is reduced, thus causing adverse effects on knitting, or stress is unevenly applied during up-and-down movement of the knitting tool, thus hastening partial deterioration in the knitting tool.

[0010] An effect that a lubricant acting between the knitting tool and the insert piece stays at the wave-shaped part or the like is obtained to a certain extent. However, in order to reduce the contact areas, the wavy shape or the like is formed to be comparatively large. Therefore, there is a large area where the wavy shape or the like does not overlap the knitting tool but protrudes out therefrom, so that the lubricant flows to outside from the wave-shaped part or the like and thus the effect of reducing the frictional force might not be sufficiently obtained. Therefore, the conventional processing for reducing the frictional force is not necessarily commensurate with time and cost taken for the processing and the like.

[0011] Further, in recent years, demand for high-speed operation of the circular knitting machine has been increasing. Along with this, power consumption by operation of the circular knitting machine increases. In addition, if the frictional force of the knitting tool is great, the power for driving increases accordingly, so that the cost is also increased. Therefore, it is necessary to reduce the frictional force.

DISCLOSURE OF THE INVENTION



[0012] The present invention has been made to solve the above problems and an object of the present invention is to provide a needle bed for a circular knitting machine in which, without greatly changing the structures of a knitting tool and an insert piece for forming a groove for slidably storing the knitting tool, the contact area between the insert piece and the knitting tool that slides along the insert piece is reduced so as to reduce the frictional force.

[0013] In order to attain the above object, a needle bed for a circular knitting machine according to the present invention is a needle bed which is mountable to the circular knitting machine, the needle bed being configured to allow a knitting tool to be slidably stored in a groove of which both side surfaces are formed by opposed plate surfaces of adjacent insert pieces having a rectangular plate shape, wherein each insert piece has a plurality of dimples formed in a short-side direction and a long-side direction on the plate surfaces.

[0014] In the above configuration, a plurality of dimples are provided in the short-side direction and the long-side direction on the insert piece. Therefore, the structure of the insert piece itself is not greatly changed, unlike the conventional case in which a wavy shape or the like is formed. Thus, time and cost for processing are decreased and also, processing dimension accuracy can be prevented from being influenced. Further, since a plurality of comparatively small dimples are provided, the contact area between the insert piece and the knitting tool is reduced, so that the frictional force can be effectively reduced. In addition, discharge of a lubricant to the outside can be also suppressed.

[0015] In the present invention, preferably, the insert piece is formed to be separated into a flat-surface area having no dimples and a dimple area having dimples, in the short-side direction, and a dimension of each dimple in the short-side direction is equal to or smaller than 1/4 of a dimension of the insert piece in the short-side direction. An area up to about half of the dimension in the short-side direction of the insert piece is used as an area bonded to a base material, and the remaining half area is used to form a side surface of the needle groove. In addition, the dimension in the short-side direction of the knitting tool is often equal to or greater than 1/2 of the dimension in the short-side direction of the insert piece. Therefore, if the dimension of the dimple is equal to or smaller than 1/4 of the dimension in the short-side direction of the insert piece, the dimple and the knitting tool overlap each other in the short-side direction or such an overlapping part can be increased.

[0016] In the present invention, preferably, a dimension of the dimple in the short-side direction is smaller than a dimension of the knitting tool in the short-side direction. In this case, the dimple and the knitting tool overlap each other in the short-side direction or such an overlapping part can be increased. Since a plurality of comparatively small dimples are provided, the contact area between the insert piece and the knitting tool is reduced, so that the frictional force can be more effectively reduced. In addition, discharge of a lubricant to the outside can be further suppressed.

[0017] Preferably, the dimples are formed such that the dimples formed on the plate surfaces on front and back sides are shifted from each other so as not to overlap each other in a thickness direction of the insert piece. Thus, since the dimples on the front and back plate surfaces are shifted from each other, there are no dimples directly on the back side of the dimples on the front side, and thus it is ensured that the thickness of the insert piece is uniform, so that the strength is not reduced due to formation of dimples.

[0018] Preferably, a dimension of each dimple in the short-side direction is equal to or smaller than 2.0 mm. More preferably, the dimension is equal to or smaller than 1.0 mm. Thus, the contact area between the insert piece and the knitting tool is reduced, so that the frictional force can be more effectively reduced, and in addition, discharge of a lubricant to the outside can be further suppressed.

[0019] Preferably, the dimples are formed by dimple processing in which dimples having identical shapes are formed at regular intervals in each of the short-side direction and the long-side direction. Therefore, it is possible to easily form dimples without influencing processing dimension accuracy by dimple processing, and the surface hardness of the plate material can be increased. In addition, since the dimples are arranged at regular intervals, the lubricant retaining effect can be exerted over the entire area without unevenness.

[0020] Preferably, the dimples are arranged uniformly over an entirety of the dimple area. Thus, the degree of effect does not vary depending on positions in the dimple area, and the friction reducing effect can be obtained at an equal level everywhere in the dimple area.

[0021] In the present invention, preferably, a circular knitting machine includes the above needle bed. In this case, it is possible to obtain a circular knitting machine including a needle bed in which, without greatly changing the structures of the insert piece and the knitting tool, the contact area between the insert piece and the knitting tool that slides along the insert piece is reduced so as to reduce the frictional force.

[0022] The present invention makes it possible to, without greatly changing the structures of a knitting tool and an insert piece for forming a groove for slidably storing the knitting tool, reduce the contact area between the insert piece and the knitting tool that slides along the insert piece, so as to reduce the frictional force.

[0023] Any combination of at least two constructions, disclosed in the appended claims and/or the specification and/or the accompanying drawings should be construed as included within the scope of the present invention. In particular, any combination of two or more of the appended claims should be equally construed as included within the scope of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS



[0024] In any event, the present invention will become more clearly understood from the following description of preferred embodiments thereof, when taken in conjunction with the accompanying drawings. However, the embodiments and the drawings are given only for the purpose of illustration and explanation, and are not to be taken as limiting the scope of the present invention in any way whatsoever, which scope is to be determined by the appended claims. In the accompanying drawings, like reference numerals are used to denote like parts throughout the several views, and:

Fig. 1 is a front view of an entire single-knit circular knitting machine according to the first embodiment of the present invention;

Fig. 2 is a partial vertical sectional view of a knitting portion of the single-knit circular knitting machine;

Fig. 3 is a horizontal sectional view of a needle cylinder;

Fig. 4 is a partial sectional view of a needle bed with a partial enlarged view thereof;

Fig. 5 is an enlarged sectional view of part V in Fig. 3, showing a state in which a needle slides between insert pieces; and

Fig. 6 is a side view of a sinker according to the second embodiment of the present invention.


DESCRIPTION OF EMBODIMENTS



[0025] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Fig. 1 is a front view showing a circular knitting machine 10 having a needle bed according to the first embodiment of the present invention. The circular knitting machine 10 is, for example, a single-knit circular knitting machine, and includes a knitting portion 12 for knitting a tubular knitted fabric, a winding portion 13 for winding the tubular knitted fabric, and a control portion 16 for controlling the entire circular knitting machine.

[0026] In Fig. 1, the knitting portion 12 is provided above a bed 22 supported by a plurality of legs 21. A plurality of posts 24 stand on the bed 22, and a horizontal member 25 is fixed at upper parts of the posts 24 by connection members. A yarn feed portion 9 is supported by the horizontal member 25. The knitting portion 12 is controlled by the control portion 16 so that a needle cylinder 33 (Fig. 2) in which a plurality of cylinder needles 31 (Fig. 2) are slidably stored in cylinder needle grooves 32 (Fig. 2) is rotated by being driven by a main motor 15, and a yarn 11 is fed to each cylinder needle 31 (Fig. 2) via the yarn feed portion 9 to helically stack stitches, thereby forming a tubular knitted fabric. The formed knitted fabric is wound by the winding portion 13 including a plurality of winding rollers provided below the bed 22.

[0027] Fig. 2 shows a partial vertical sectional view of the knitting portion 12 of the single-knit circular knitting machine. The single-knit circular knitting machine includes the needle cylinder 33 having a cylindrical shape, a sinker dial 36 is disposed to an upper part of the needle cylinder 33, and the needle cylinder 33 and the sinker dial 36 rotate synchronously with each other. Each cylinder needle 31 is inserted into the cylinder needle groove 32 formed vertically on the outer circumference of the needle cylinder 33. A cylinder cam 34 is attached to a cam holder 42. By driving of the main motor 15 (Fig. 1), a gear ring 37 is rotated, and the needle cylinder 33 fixed to an upper part of the gear ring 37 is rotated, whereby a needle butt 45 of each cylinder needle 31 is guided by a cylinder cam race 38, to perform up-and-down movement.

[0028] Sinkers 35 for assisting loop formation are inserted into sinker grooves formed radially on the sinker dial 36. A sinker cam 43 is attached to a sinker cap 41. When the sinker dial 36 is rotated by driving the circular knitting machine, a sinker butt 44 of each sinker 35 is guided by a sinker cam race 40, to perform back-and-forth movement. Each sinker 35 is inserted into grooves of the sinker dial 36 and a sinker rest ring 39. The cylinder needle 31 and the sinker 35 are disposed perpendicularly with each other, and form a loop by their mutual movements, thereby producing a tubular knitted fabric.

[0029] Although not provided in this example, the needle bed 30 may store, as well as the cylinder needles 31 and the sinkers 35, knitting tools such as jacks (not shown) of a needle selection device, which are moved during operation of the circular knitting machine while being guided by cams, the needle selection device, or the like.

[0030] Fig. 3 is a horizontal sectional view of the needle cylinder 33. The needle bed 30 is formed by cutting a base material of the needle cylinder 33 by a cutter to form insert piece grooves 51, inserting insert pieces 50 having a rectangular plate shape into the insert piece grooves 51, and then bonding them by an adhesive agent. Then, each cylinder needle 31 is inserted into the cylinder needle groove of which both side surfaces are formed by opposed plate surfaces of the adjacent insert pieces 50 and thus is slidably stored therein (Fig. 2).

[0031] Fig. 4 is a partial sectional view of the needle bed 30 and a partial enlarged view thereof. Multiple dimples 53 are provided in a short-side direction X and a long-side direction Y on both front and back surfaces of each insert piece 50 serving as contact surfaces with the cylinder needle 31. The insert piece 50 is formed to be separated into a flat-surface area 50A having no dimples 53 and a dimple area 50B in the short-side direction X.

[0032] In general, the cylinder needle 31 has a meander shape as shown in Fig. 4, for the purpose of preventing needle breaking, and the like. Each dimple 53 formed on the insert piece 50 has a round recessed shape, and has a diameter smaller than the dimension in the short-side direction X of the cylinder needle 31 which is a knitting tool. The dimension in the short-side direction of the cylinder needle 31 is often equal to or greater than 1/4 of the dimension in the short-side direction of the insert piece 50. Therefore, if the diameter of the dimple 53 is equal to or smaller than 1/4 of the dimension in the short-side direction of the insert piece 50, the cylinder needle 31 and the dimple 53 overlap each other in the short-side direction X or such an overlapping part can be increased. In addition, since a plurality of dimples 53 having a small diameter are provided in the insert piece 50 and are not communicated with the outside, a lubricant is less likely to be discharged to the outside and stays there, so that the lubricant retaining effect is high. Thus, the frictional force between the cylinder needle 31 and the insert piece 50 can be reduced.

[0033] In addition, the dimension in the short-side direction X of the cylinder needle 31 is often about 1/2 of the height of the side walls, of the cylinder needle groove 32, that extend in the short-side direction X. Therefore, if the diameter of the dimple 53 is equal to or smaller than 1/2 of the dimension in the short-side direction X of the cylinder needle groove 32, the cylinder needle 31 and the dimple 53 almost overlap each other in the short-side direction X or such an overlapping part increases. In the case where one great dimple is formed in the short-side direction in the insert piece so as to be arranged in a row in the long-side direction as shown in Chinese Patent Publication No. 101805955, even half of the dimple does not overlap the cylinder needle, so that the effect of reducing the frictional force might be reduced. In contrast, in the present invention, a plurality of small dimples are arranged in the short-side direction X and the long-side direction Y, to reduce the frictional force.

[0034] Further, regarding the insert piece 50 itself, an area up to about half of the dimension in the short-side direction X is used as an area bonded to the base material, and the remaining half area becomes the side wall of the cylinder needle groove 32. Then, half of the side wall is the dimple area. Therefore, if the diameter of the dimple 53 is about 1/4 of the dimension in the short-side direction X of the insert piece 50, effects of the present invention can be sufficiently obtained.

[0035] In this example, the dimensions in long-side direction Y × short-side direction X of the insert piece 50 are about 150 mm × 8 mm. In addition, as shown in Fig. 4, the cylinder needle 31 has a varying shape with a tip end needle part, needle butts 45, and the like, and thus the dimension in the short-side direction X of the cylinder needle 31 is in a range of about 1.0 to 6.5 mm. As described above, if the diameter of the dimple 53 is about 1/4 of the dimension in the short-side direction X of the insert piece 50, the effect of reducing the frictional force is obtained. Therefore, preferably, the diameter D of the dimple 53 is equal to or smaller than 2.0 mm. Further, in consideration of the minimum value of the dimension in the short-side direction X of the cylinder needle 31, it is particularly preferable that the diameter D of the dimple 53 is equal to or smaller than 1.0 mm. In addition, in consideration of the effect of retaining the lubricant, a depth H of the dimple 53 is preferably 5 to 20 µm (0.005 to 0.02 mm). Even though the dimple 53 has such a small-diameter shape, since the dimples 53 are arranged in a zig-zag form, the entire contact area between the insert piece 50 and the cylinder needle 31 is halved as compared to the case where there are no dimples, and thus the frictional force can be reduced. Providing multiple small dimples 53 can reduce the frictional force and increases the effect of retaining the lubricant.

[0036] In this example, as shown in the partial enlarged view in Fig. 4, on the plate surfaces of the insert piece 50, round dimples 53 having identical shapes are arranged at regular intervals in a staggered form, that is, such multiple dimples 53 are arranged in a zig-zag form in the short-side direction X and the long-side direction Y. Solid-line circles represent the dimples 53 on the front surface, and dotted-line circles represent the dimples 53 on the back surface. The dimples 53 on the front and back surfaces of the plate material of the insert piece 50 are formed to be shifted from each other so as not to overlap each other in the thickness direction. Therefore, the thickness of the insert piece 50 after dimple processing is kept almost uniform as a whole and the insert piece 50 has a uniform strength.

[0037] Fig. 5 is an enlarged sectional view of part V in Fig. 3, showing a state in which the cylinder needle 31 slides between the insert pieces 50. As shown in Fig. 5, the cylinder needle 31 slides in the long-side direction Y (see Fig. 4) between the adjacent insert pieces 50. On the surface of the insert piece 50, a plurality of dimples 53 are formed by dimple processing in which dimples having identical shapes are formed at regular intervals in each of the short-side direction X and the long-side direction Y.

[0038] The dimples 53 are formed by performing dimple processing on both surfaces of the plate material with use of a general normal press. There is no influence on processing dimension accuracy by dimple processing, and owing to the effect of applying pressure on both surfaces in this processing, the surface hardness of the insert piece 50 can be increased.

[0039] Power consumption was measured for the case of the needle bed using the insert pieces according to the present invention and the case of a normal needle bed using normal insert pieces with no dimples, and the measured power consumptions were compared. The common knitting conditions were as follows: the diameter of the circular knitting machine was 30 inches, the gauge thereof was 28 G, the rotation speed of the circular knitting machine was 40 rpm, the yarn was a polyester yarn of 167 dtex (deci-tex), the knit texture was plain stitch, the stitch density was 240 mm / 100 W (wale), and the circular knitting machine was operated 2000 times to form a knitted fabric.

[0040] As a result, power consumption in the case of the normal needle bed was 2223.9 Wh. On the other hand, power consumption in the case of the needle bed using the insert pieces according to the present invention was 1901.6 Wh. Thus, it was confirmed that a power consumption reduction effect of 14.5% was obtained by reduction in the frictional force due to the dimples 53.

[0041] In this example, the single-knit circular knitting machine is used. In the case of the double-knit circular knitting machine (not shown), as in the single-knit circular knitting machine, dimples are formed on the insert piece 50 of each cylinder needle groove on which the cylinder needle slides, and in a needle bed storing dial needles, jacks, and the like, dimples are formed in an insert piece of each dial needle groove on which the dial needle slides. Thus, as in the single-knit circular knitting machine described above, it is possible to reduce the frictional force by dimples in each needle bed.

[0042] Fig. 6 is a side view of a sinker according to the second embodiment of the present invention. In this example, a plurality of round dimples 53a are formed on the front and back surfaces of a plate-shaped sinker 35 which horizontally moves relative to a needle moving up and down, so as to assist loop formation. The other configurations are the same as those in the first embodiment. However, the dimples 53 may not be formed on the insert pieces of the needle bed according to the first embodiment.

[0043] The sinker 35 performs back-and-forth movement in the radial direction of the needle cylinder 33. At this time, as shown in Fig. 2, of the sinker 35, a center part on the front side in the center direction of the needle cylinder 33 and almost the entirety of the lower part on the rear side in the opposite direction, cause friction with the groove storing the sinker 35. Therefore, in Fig. 6, the dimples 53a are formed at the center part on the front side and in the entire area on the rear side of the sinker 35. As long as the dimples 53a have a diameter within the range of the knitting tool, the effect thereof is obtained. In this example, preferably, a large number of small dimples are provided in order to provide the lubricant retaining effect uniformly over the entire area. Therefore, by dimple processing, a plurality of minute round dimples 53a are formed at regular intervals in the front-rear direction and the vertical direction.

[0044] Besides the sinkers 35 as described in this example, dimples may be provided to knitting tools such as needles or jacks, whereby the same effect can be obtained without providing dimples to the needle bed. In the case where the dimples 53a are provided to the sinker 35, an effect can be obtained without providing the dimples 53 to the insert piece 50, and thus it becomes unnecessary to perform dimple processing on the needle bed.

[0045] As described above, in the plate-shaped knitting tool which can be slidably stored in the groove formed on the needle bed of the circular knitting machine, a plurality of dimples are provided in the short-side direction and the long-side direction on two side surfaces on the front and back sides, which have the largest area. By using such a plate-shaped knitting tool for a circular knitting machine, it becomes possible to, without greatly changing the structures of the knitting tool and the groove for slidably storing the knitting tool, reduce the contact area between the groove and the knitting tool that slides along the groove and reduce the frictional force therebetween.

[0046] The knitting tool is formed to be separated into a flat-surface area having no dimples and a dimple area having dimples, in the short-side direction. If the dimension of the dimple in the short-side direction is smaller than that of the knitting tool, the dimples are not communicated with the outside, so that the lubricant is retained and the friction is reduced.

[0047] In the knitting tool stored in the groove, if the dimples are provided in areas including the contact part with the groove, the contact area at the contact part is reduced owing to the dimples, whereby the friction can be reduced.

[0048] The dimples may be formed such that the dimples formed on both side surfaces are shifted from each other so as not to overlap each other in the thickness direction of the knitting tool. Thus, the thickness of the knitting tool after dimple processing is kept almost uniform as a whole and the knitting tool has a uniform strength.

[0049] Preferably, the dimension of the dimple in the short-side direction is equal to or smaller than 1.0 mm. In this case, the dimension of the dimple in the short-side direction is smaller than the needle having the smallest dimension in the short-side direction among the knitting tools. Therefore, the dimples are kept within the range of the surface of the knitting tool and the dimples are not communicated with the outside, so that the lubricant can be retained and the friction can be reduced.

[0050] Preferably, the dimple area on one of the side surfaces is provided so as to include a peripheral end area on one side in the short-side direction, and the dimple area on the other one of the side surfaces is provided so as to include a peripheral end area on the side, in the short-side direction, that is opposite to the former peripheral end area. Thus, the dimple areas can be provided at parts where the knitting tool and the groove strongly contact each other when the knitting tool is inclined due to rotation of the circular knitting machine, whereby the friction can be effectively reduced.

[0051] In the single-knit circular knitting machine using the sinker 35, a groove that can store the knitting tool is directly formed on the sinker dial 36 and the sinker rest ring 39 shown in Fig. 2, and the plate-shaped sinker 35 slides in the groove. Therefore, it is necessary to reduce the frictional force as in the first embodiment, and a plurality of dimples 53a described above are formed on the front and back surfaces of the sinker 35 as shown in Fig. 6.

[0052] As described above, in the present invention, a plurality of dimples are formed on the contact surface of the insert piece and the knitting tool so as to reduce the contact area, whereby the frictional force can be reduced and thus power consumption can be reduced. In addition, owing to the effect of retaining the lubricant by the dimples, the use amount of the lubricant can be reduced. Further, the dimples on the front and back surfaces serving as the contact surfaces are shifted from each other, whereby a uniform plate thickness can be ensured and the strength can be prevented from being reduced due to the dimples.

[0053] In the above embodiments, the dimples have a round recessed shape. However, without limitation thereto, the dimples may have an elliptic shape, a polygonal shape, or the like, instead of a round shape. In the above embodiments, the dimples 53 have identical shapes and are arranged at regular intervals in a staggered form. However, without limitation thereto, the shape or the intervals may be varied. Further, the dimples may be provided to one surface or both surfaces of the insert piece or the knitting tool. In the case of providing the dimples on one surface, it is preferable that the dimples are provided on the surface that faces a direction opposite to the rotation direction of the needle bed. The dimple areas may be formed in a scattered manner at several locations on the surface, instead of being formed over the entire surface. In the case where the dimples are provided on both surfaces, the dimple areas may be formed so as not to overlap each other partially or entirely in the thickness direction of the insert piece.

[0054] Although the present invention has been fully described in connection with the preferred embodiments thereof with reference to the accompanying drawings which are used only for the purpose of illustration, those skilled in the art will readily conceive numerous changes and modifications within the framework of obviousness upon the reading of the specification herein presented of the present invention. Accordingly, such changes and modifications are, unless they depart from the scope of the present invention as delivered from the claims annexed hereto, to be construed as included therein.

[Reference Numerals]



[0055] 
10
····circular knitting machine
12
····knitting portion
30
····needle bed
31
····cylinder needle
32
····cylinder needle groove
33
····needle cylinder
35
····sinker
50
····insert piece
50A
····flat-surface area
50B
····dimple area
53 (53a)
····dimple
X
····short-side direction
Y
····long-side direction



Claims

1. A needle bed (30) for a circular knitting machine (10), which is mountable to the circular knitting machine (10), the needle bed (30) being configured to allow a knitting tool (31) to be slidably stored in a groove (32) of which both side surfaces are formed by opposed plate surfaces of adjacent insert pieces (50) having a rectangular plate shape, wherein
each insert piece (50) has a plurality of dimples (53) formed in a short-side direction and a long-side direction on the plate surfaces.
 
2. The needle bed (30) as claimed in claim 1, wherein
each insert piece (50) is formed to be separated into a flat-surface area (50A) having no dimples (53) and a dimple area (50B) having dimples (53), in the short-side direction, and a dimension of each dimple (53) in the short-side direction is equal to or smaller than 1/4 of a dimension of the insert piece (50) in the short-side direction.
 
3. The needle bed (30) as claimed in claim 1 or 2, wherein
a dimension of the dimple (53) in the short-side direction is smaller than a dimension of the knitting tool (31) in the short-side direction.
 
4. The needle bed (30) as claimed in any one of claims 1 to 3, wherein
the dimples (53) are formed such that the dimples (53) formed on the plate surfaces on front and back sides are shifted from each other so as not to overlap each other in a thickness direction of the insert piece (50).
 
5. The needle bed (30) as claimed in any one of claims 1 to 4, wherein
a dimension of each dimple (53) in the short-side direction is equal to or smaller than 2.0 mm.
 
6. The needle bed (30) as claimed in any one of claims 1 to 4, wherein
a dimension of each dimple (53) in the short-side direction is equal to or smaller than 1.0 mm.
 
7. The needle bed as claimed in any one of claims 1 to 6, wherein
the dimples (53) are arranged uniformly over an entirety of the dimple area (50B).
 
8. The needle bed (30) as claimed in any one of claims 1 to 7, wherein
the dimples (53) are formed by dimple processing in which dimples (53) having identical shapes are formed at regular intervals in each of the short-side direction and the long-side direction.
 
9. A circular knitting machine (10) comprising the needle bed (30) as claimed in any one of claims 1 to 8.
 




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REFERENCES CITED IN THE DESCRIPTION



This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.

Patent documents cited in the description