Flat knitting machine

Abstract: A pair of needle beds (1) are provided with head portions thereof opposed to each other and a plurality of sinkers (15) are provided in a juxtaposed relationship at the head portions of the needle beds. First and second needles (8₁F, 8₁B; 8₂F, 8₂B) each having a transfer element are provided for sliding movement between each adjacent pair of sinkers (15). The first and second needles are either provided alternately at an equal distance from each other throughout each needle bed or are individually provided at an equally spaced relationship from each other between the sinkers but such that the distance between adjacent needles positioned on opposite sides of each sinker is different from the distance between first and second needles between the sinkers.

Description: Field of the Invention This invention relates to flat knitting machines. Prior Art One method of knitting a piece of non-sewn clothing utilising a flat knitting machine is known wherein, using at least one pair of needle beds having head portions opposed to each other, loops of a knitted fabric are suitably transferred between the opposed needle beds to form the body, the sleeves and other parts into a unitary fabric. Examples of this method are described in Japanese published patent application No. Heisei 3-75656, British patent application GB-A-2183264, and British patent application GB-A-2228750. It is disclosed in the Japanese published patent application No. Heisei 3-75656 and in the specification of GB-A-2183264 mentioned above that, in order to knit a tubular knitted fabric having an arbitrary link and link pattern including a rib stitch, a purl stitch, a link and link stitch and so forth, using a well-known type of V-bed knitting machine, needles provided in a juxtaposed relationship on the needle beds are used in a divided condition. For example, odd-numbered needles are used to knit a front portion of a tubular knitted fabric while even-numbered needles are used to knit a back portion of tubular knitted fabric. For example, in order to knit a front portion of a tubular knitted fabric having a wide rib stitch, such preparations for knitting of the front portion of the tubular knitted fabric as to transfer those loops of the front portion of the tubular knitted fabric carried on the needles on the front needle bed which are to be formed as purl stitches in the current course to the back needle bed in accordance with a design pattern are completed first, and then knitting of the front portion of the tubular knitted fabric for the current course is performed. Thereafter, prior to knitting of a back portion of the tubular knitted fabric, loops of the front portion of the tubular knitted fabric knitted on the back needle bed are transferred back to the front needle bed, and those loops which are to be formed as purl stitches of the back portion of the tubular knitted fabric in the current course are transferred to the corresponding needles of the front needle bed in accordance with the design pattern in a similar manner as with the front portion of the tubular knitted fabric, whereafter knitting of the back portion of the tubular knitted fabric is performed. The sequence of operations described above is repeated to form a tubular knitted fabric. British patent application GB-A-2228750 discloses two embodiments for knitting a tubular knitted fabric. One of the embodiments is directed to a knitting method for a tubular sweater or a pullover of a raglan sleeve type using a so-called "four-bed flat knitting machine" wherein a pair of upper beds and a pair of lower beds are provided in pairs on the front and the back. The other embodiment is directed to another knitting method for a tubular sweater or a pullover of a set-in sleeve type wherein the tubular sweater is knitted by classifying needles on a flat knitting machine which includes a pair of front and back needle beds. In knitting using a flat knitting machine which includes a pair of front and back needle beds such as the knitting method just described, since a tubular knitted fabric is knitted using only selected ones of the needles of the opposed needle beds without modifying the structure of the needle beds themselves, the distance between adjacent needle loops on a needle bed becomes larger than the distance between adjacent needles on the needle bed, and consequently, the size of a knitted sinker loop becomes much greater than the size of a needle loop. This results not only in a degradation of the feel of the knitted fabric, but also in degradation of the elastic property, particularly the elastic property in a lateral direction, which is the most significant characteristic of a knitted fabric. For example, with a needle bed of 7 gauge, the distance between adjacent needles is 3.628 mm, but if alternate ones of the needles are used, then the distance between adjacent used needles is 7.257 mm. When a plain stitch is knitted, two sinkers are present between adjacent loops, which further increases the length of a sinker loop between the needle loops and further impairs the knitting conditions. EP-A-0238797 describes a two-bed flat knitting machine with small plates between the needles in the two needle beds. The small plates which are pivotable to form a bridge over the gap between the opposed heads of the needle beds each comprise a sinker edge which is below the respective projections forming the bridge, so that the old stitch is reliably held in the gap and by means of the small plates a balanced sinking movement is performed. SUMMARY OF THE INVENTION In view of the foregoing, it is an object of the present invention to provide a flat knitting machine wherein sinker loops do not have a large size when a knitted fabric is knitted using a pair of opposed needle beds under the condition that inoperative needles are present while the needle beds are used solely or simultaneously, so that the flat knitting machine can knit a knitted fabric of a high quality which does not have an inferior feel. In accordance with the invention there is provided a flat knitting machine comprising a pair of needle beds having head portions opposed to each other, and a plurality of sinkers provided in a juxtaposed relationship at said head portions of said needle beds, characterised in that first and second needles each having a transfer element are provided for sliding movement between each adjacent pair of said sinkers. The sinkers are preferably provided in a spaced relationship from each other by a distance corresponding to a predetermined gauge value. The first and second needles are either provided alternately at an equal distance from each other throughout each needle bed or are individually provided at an equally spaced relationship from each other between the sinkers but such that the distance between adjacent needles positioned on opposite sides of each sinker is different from the distance between first and second needles between the sinkers. Further, the ratio of the distance between the needle grooves of the first and second needles positioned between adjacent pairs of the sinker plates and the distance between one of the first and second needles and an adjacent needle positioned on the opposite side of the sinker plate is set to range from 1:1 to 1:2.8. The first and second needles preferably have hooks having an equal size greater than the size of an ordinary hook with respect to the distance between each adjacent pair of needles so that the sinker loops of a knitted fabric may have a size which is substantially equal to or is not much larger than the size of needle loops of the knitted fabric. Two needles are provided between each adjacent pair of sinkers provided in a juxtaposed relationship at the head portions of the needle beds. In order to knit a tubular knitted fabric having a links and links pattern, knit stitches are knitted on the front needle bed while purl stitches are knitted on the back needle bed, and accordingly, loops of a wale are transferred between the front and back needle beds. In order to knit a front fabric and a back fabric on the needle beds in pairs, those needles to knit knit stitches and those needles to knit purl stitches on each needle bed must be used in a divided condition. As a result, those needles which can be used to knit a knit stitch or a purl stitch are alternate first or second needles, and the other needles which are not used are left at their rest positions. During knitting, when a first or second needle in an operative condition catches a knitting yarn and passes it through a needle loop of the last course to form a new needle loop, sinker loops connecting to the new needle loop are contacted by sinkers positioned on the opposite sides of the needle. However, since no sinker is provided between the needle and the second or first needle positioned between the sinkers together with the needle, forward projection of the yarn by a sinker in the proximity of the operative needle is not caused, and consequently an increase in size of the sinker loop is prevented. The difference in size between the sinker loop and the needle loop is reduced also by the fact that the size of the needle loop is increased by having the hooks of the first and second needles of a larger size. The sinkers provided on the needle beds have a spacing corresponding to the predetermined gauge value, and the first and second needles are inserted between the sinkers. When a cardigan rib stitch is knitted on a tubular fabric, every other needle is used for the knitting of a course. Accordingly, by inserting, between the sinkers, needles having a needle density twice the needle density corresponding to the predetermined gauge, a knitted fabric having a number of wales equal to the number of wales in the predetermined gauge can be knitted. BRIEF DESCRIPTION OF THE DRAWINGS Figs. 1A and 1B are sectional views through needle beds of a flat knitting machine in accordance with the present invention. Fig. 2 is an enlarged plan view of the head portions of the needle beds of the flat knitting machine of the present invention. Fig. 3 shows needles which can be used with the flat knitting machine of the present invention: Figs. 3A and 3B show a needle having a blade; Fig. 3C shows a needle having a recessed portion; and Fig. 3D shows a needle having a slider. Figs. 4A, 4B and 4C are schematic views of the head portions of the opposed needle beds illustrating the positions of blades of needles inserted between sinkers. Figs. 5A, 5B, 5C and 5D are plan views illustrating the relationship between needles and a knitting yarn and illustrating a knitting process for a 1x1 rib stitch. DESCRIPTION OF PREFERRED EMBODIMENT An embodiment in accordance with the present invention will now be described with reference to the drawings. Figs. 1A and 1B show vertical sectional views through a needle bed 1, and Fig. 2 shows an enlarged plan view, partly in section. In the flat knitting machine of the present invention, two needle beds 1 are provided, namely a front bed FB and a back bed BB disposed on respective opposite sides of an imaginary vertical centre plane V, with the head portions of the beds opposed to each other in a peak-like configuration. Since the needle beds 1 of the front bed FB and the back bed BB have the same structure, only the structure of the needle bed of the front bed FB will be described below. The needle bed 1 has a plurality of parallel needle plate grooves 2 formed therein by machining, and a needle plate 3 is inserted in each of the needle plate grooves 2. An oblique recess 4 is formed in a lower face of each of the needle plates 3, and another oblique recess 5 is formed in an upper face of the needle bed 1. The needle plates 3 and the needle bed 1 are arranged so that the recesses 4 and the recess 5 are aligned with each other and a wire 6 is threaded through the thus-aligned recesses 4 and 5, while tail portions of the needle plates 3 and of the needle bed 1 are caulked to each other to secure the needle plates 3 and the needle bed 1 to each other. The needle plates 3 comprise needle plates 3a of a greater thickness and needle plates 3b of a lesser thickness arranged alternately with each other. Thus, a needle groove 7 is formed between each adjacent pair of needle plates 3. A needle 8, a needle jack 9 for operating the needle 8, a selector 10 and a select jack 11 are inserted for sliding movement in each of the needle grooves 7. The needles 8 are prevented from coming out of the needle grooves 7 by a band 12 fitted in the needle plates 3 and extending in a direction perpendicular to the needle grooves 7. A transfer needle having a transfer element 13 provided thereon is employed for the needles 8. Examples of needles 8 having such a transfer element 13 are shown in Fig. 3. The needle 8a shown in Figs. 3A and 3B has an arch-shaped blade 13a projecting from a side face of the body of the needle; the needle 8b shown in Fig. 3C has a recessed portion 13b provided in a side face of the body of the needle; and the needle 8c shown in Fig. 3D has a slider 13c provided at an upper portion of the body of the needle for sliding movement relative to the body of the needle. In the needle 8a having the blade 13a projecting from a side face thereof like the needle 8a shown in Figs. 3A and 3B, the transfer element 13 may be provided either on the right-hand face or the lefthand face of the body of the needle. Each of the needle plates 3 has a blade accommodating groove 14 formed therein by machining so that a blade 13a does not make contact with the needle plate 3. Particularly in the case of the needle plates 3b having a lesser thickness, the blade accommodating groove 14 extends from one side to the other side of the needle plate 3b. The blades 13a may be provided, as shown in Fig. 4A, all on the same side faces (facing to the left or right) of the bodies of all of the needles. Alternatively, they may be provided, as shown in Fig. 4B, on opposed side faces of two needles between each pair of adjacent sinker plates 15. Yet again, they may be provided, as shown in Fig. 4C, on the opposite faces of the two needles to those just described. In the cases shown in Fig. 4, grooves for mounting a first needle and a second needle which will be described hereinafter can be constructed as a single needle groove, and in this instance it is necessary to provide a spacer or like element between such two needles as described above in order to prevent interference between the needles, so that an advancing or retracting movement of an individual needle does not have an adverse influence on the adjacent needle. As shown in Figs. 1A and 1B a plurality of sinker plate fitting grooves 16 are provided parallel to each other in a lower face of the front end portion of the needle bed 1, at an acute angle, and a sinker plate 15 formed as a plate having an obtuse-angled, substantially L-shaped side profile is fitted in each of the sinker plate fitting grooves 16. The sinker plate 15 has, at the forward end thereof, a rectangular portion 17 partially arrested on the needle bed 1 and also has, at the rear portion thereof, a hook 18 arrested in a recess 19 formed in the lower face of the needle bed 1, thereby to fix the sinker plate 15 to the needle bed 1. Reference numerals 20 and 21 denote wires threaded through the sinker plates 15. The wire 20 acts as a loop holding wire to hold loops of a knitted fabric depending from a knock-over edge of the needle bed 1 and provides the knock-over timing. It is to be understood of course that the sinker plates 15 need not necessarily be fixed as described above but may instead be plate members which are provided at an end portion of the needle bed for forward and backward movement or pivotal movement towards and away from the knock-over edge of the needle bed. The sinker plates 15 are provided one for every two needles as shown in Fig. 2. Two needles located between two adjacent sinker plates 15, 15 are hereinafter referred to as first needle 8 1 and second needle 8 2 . In the example shown in Fig. 2, the distance between two needle grooves, that is, between two needles positioned on opposite sides of a sinker plate 15 is 2.540 mm, which is larger than the distance of 1.693 mm between two adjacent needles. However, all of the needle grooves are provided at an equidistantly spaced relationship from each other. Fig. 4 shows several arrangements of needles and sinkers by way of example for a knitting machine of 6 gauge. In this instance, three needles are used per inch, and consequently the substantial needle distance is equal to the needle distance of a knitting machine of 3 gauge. In order to raise the needle density, twelve needles are sometimes provided in a knitting machine which corresponds to a machine of 6 gauge. In the case of Fig. 4A, it can be seen that the needles used are thinner than needles for use with a knitting machine of 6 gauge, and therefore the distance between first and second needles is set equal to that of a knitting machine of 15 gauge (1.693 mm); the distance between one of the first and second needles and a needle positioned on the other side of a sinker is set equal to that of a knitting machine of 10 gauge (2.540 mm); and the distance between sinkers is set equal to that of a knitting machine of 6 gauge (4.233 mm) which is equal to the distance between first needles or second needles. Further, the hook size of needles mounted is equal to that of a knitting machine of, for example, 7 gauge so that the balance between sinker loops and needle loops of a knitted fabric is not degraded very much. In Fig. 4A, the ratio of the distance between two needles positioned between two sinkers and the distance between two adjacent needles on opposite sides of a sinker is 1:1.5. Similarly, the ratio in the example of Fig. 4B is 1:1, and the ratio in the example of Fig. 4C is 1:2.8. Preferably, the ratio of the distance between two needles positioned between two sinkers and the distance between two adjacent needles on opposite sides of a sinker ranges from 1:1 to 1:2.8. In particular, where the distance between two adjacent needles on opposite sides of a sinker is smaller than the distance between two needles positioned between two sinkers, the sinkers and the needles are located so close that, when a sinker loop is pulled by a pair of needles positioned on the opposite sides of and contacting the sinker, the loop is bent very strongly between end edges of the sinker and the hooks of the needles, which causes a yarn breakage or other trouble. On the contrary, where the distance between two adjacent needles on opposite sides of a sinker is greater than the 2.8 times distance between two needles positioned between two sinkers, the length of a sinker loop becomes excessively great. As a result, the resulting knitted fabric has a degraded feel with irregular stitches. A method of knitting a knitted fabric using the knitting machine of the present invention will now be described. With the knitting machine of the present invention, when a knitting yarn is supplied to the opposed needles of the pair of needle beds which have their head portions opposed to each other, loops carried on needles on one of the needle beds are sometimes transferred temporarily to needles of the opposed needle bed so that all loops are carried on the needles of one of the needle beds. It is assumed that, for example, a tubular 1x1 rib stitch is to be knitted on the flat knitting machine of the present invention, where the first needles 8 1 and the second needles 8 2 of the front bed side FB and the back bed side BB shown in Fig. 2 and Fig. 4A are disposed between the sinker plates 15, 15. The knitting process is illustrated in Fig. 5. Since the knitted fabric is a tubular fabric, a front knitted fabric FF and a back knitted fabric BF must be knitted separately from each other. Furthermore, in knitting each of the front knitted fabric FF and the back knitted fabric BF, knit stitches and purl stitches must be knitted alternately. The knitting means will be described below. In order to knit a tubular 1x1 rib stitch, loops must be formed using needles on the front bed FB and the back bed BB alternately for each wale so that knit stitches and purl stitches appear on every other wale in both the front knitted fabric FF and the back knitted fabric BF. It is assumed, as shown in Fig. 5A, that the front knitted fabric FF is carried on needles 8 1 F, 8 1 f, 8 1 F, 8 1 f, ... of the front bed FB while the back knitted fabric BF is carried on needles 8 2 B, 8 2 b, 8 2 B, 8 2 b, ... of the back bed BB so that the front and back knitted fabrics FF and BF hang in a tubular form between the front bed FB and the back bed BB. First, knitting of the front knitted fabric FF from this condition will be described. Those loops of the last course of the front knitted fabric FF which are carried on the needles 8 1 f by which purl stitches are to be formed as viewed from the front knitted fabric FF side are transferred to the needles 8 1 b of the back bed BB (Fig. 5B). Then, the front knitted fabric FF is knitted using the first needles 8 1 F of the front bed FB and the first needles 8 1 b of the back bed BB, and those loops carried on the needles 8 1 b of the back bed BB are transferred back to the first needles 8 1 f of the front bed FB (Fig. 5C). Thereafter, knitting of the back knitted fabric BF is started. Those loops carried on the needles 8 2 b by which purl stitches are to be formed as viewed from the back knitted fabric BF side are transferred to the second needles 8 2 f of the front bed FB (Fig. 5D). Then, the back knitted fabric BF is knitted using the second needles 8 2 f of the front bed FB and the second needles 8 2 B of the back bed BB, and those loops carried on the second needles 8 2 B of the front bed FB are transferred back to the second needles 8 2 b of the back bed BB (Fig. 5A). Thereafter, the knitting procedure described above is repeated. Since the knitting procedure described above is performed as a sequence of transferring loops, knitting and transferring loops, where a needle arrangement as shown in Fig. 4A is employed for example, all processes for knitting stitches can be completed, using a carriage having three cam locks, by one stroke of the carriage if, after the back knitted fabric BF is knitted, transfer of purl loops of the back knitted fabric BF from the positions of Fig. 5D to the positions of Fig. 5A and transfer of purl loops of the front knitted fabric FF from the positions of Fig. 5A to the positions of Fig. 5B are performed simultaneously by the first cam, a loop forming operation is performed by the second cam, and then transfer of purl loops of the front knitted fabric FF from the positions of Fig. 5B to the positions of Fig. 5C and transfer of purl loops of the back knitted fabric BF from the positions of Fig. 5C to the positions of Fig. 5D are performed by the third cam. In the flat knitting machine of the present invention, while two, first and second needles 8 1 and 8 2 are provided between two sinker plates 15, 15, only one of these two needles performs a loop forming operation, and a knitting yarn carried on the hook of the needle which is performing a loop forming operation contacts only the sinker plates 15, 15 positioned on the opposite sides of the needle. It does not contact the other needle which is at a rest position and is not performing a loop forming operation. The relationship between the needles 8 1 and 8 2 and new and old loops NL and OL in the knitting procedure described above will now be described with reference to Fig. 2. When a knitting yarn is supplied to a first needle 8 1 F of the front bed FB shown in Fig. 2 and then the needle 8 1 F is lowered so that the knitting yarn carried on the hook of the needle 8 1 F is passed through the old loop OL to make a new loop NL, the new loop NL extends between the two sinkers 15a and 15b between which the first needle 8 1 F and the second needle 8 2 F paired with each other are positioned. Consequently, the knitting yarn, which otherwise forms, on a conventional apparatus, a sinker loop bent at an acute angle by the sinker 15a and another sinker 15c which is positioned between the first and second needles 8 1 F and 8 2 F and indicated by an alternate long and short dash line in Fig. 2, is, with the flat knitting machine of the present invention, free from such a bent portion and extends straightforwardly between the sinker 15b and the needle 8 1 F, which prevents the sinker loop SL from becoming excessively long. Similarly, by a needle 8 1 B of the back bed, a sinker loop is not increased in size. The flat knitting machine of the present invention has the features listed below. In the flat knitting machine of the present invention, since the needles and the sinker plates are provided alternately with one sinker plate being provided for every two first and second needles, when, during knitting which is performed using only odd-numbered ones or even-numbered ones of the needles, a needle loop is retracted by a needle, a sinker loop connecting from the needle loop to another needle loop of another adjacent needle which is in a knitting operation is contacted only by one sinker plate, as compared with a conventional knitting machine where a sinker loop which connects between adjacent operative needles when the needles are retracted during knitting which is performed using every other needle is contacted by two sinker plates. Accordingly, with the flat knitting machine of the present invention, the length of sinker loops can be reduced, and the ratio of needle loops to sinker loops will not be impaired. Further, since when a sinker loop is formed, it is not extended excessively by a sinker, a knitted fabric having elasticity can be obtained. Where each of the first and second needles provided between adjacent pairs of sinkers is inserted in an individually peculiar needle groove, the first and second needles can be provided in a suitably spaced relationship from each other without interfering with each other. Where the first and second needles provided between adjacent pairs of sinkers are inserted in a single common needle track, the two needles can be located close to each other, and the needle density can be increased, which is advantageous for the manufacture of a knitting machine of fine gauge. Furthermore, both of the first and second needles can be located nearer to the centre between the two sinker plates. Where a number of needles equal to twice an ordinary number of needles corresponding to a gauge value representing the number of needles per inch are mounted, even if knitting is performed using every other needle on one of the two needle beds from the necessity of a loop transferring operation to the other, opposed needle bed, a knitted fabric can still be knitted without decreasing the number of wales of the knitted fabric with respect to the predetermined gauge value. Where the first and second needles have hooks having an equal size greater than the size of an ordinary hook with respect to the distance between adjacent needles, a good balance between sinker loops and needle loops can be maintained.

Claims: A flat knitting machine comprising a pair of needle beds (1) having head portions opposed to each other, and a plurality of sinkers (15) provided in a juxtaposed relationship at said head portions of said needle beds, characterised in that first and second needles (8 1 F, 8 2 F; 8 1 B, 8 2 B) each having a transfer element (13a; 13b; 13c) are provided for sliding movement between each adjacent pair (15a, 15b) of said sinkers (15). A flat knitting machine as claimed in claim 1, characterised in that each of said first and second needles (8 1 F, 8 2 F; 8 1 B, 8 2 B) provided between each adjacent pair of said sinkers (15) is inserted in an individually characteristic needle groove (7). A flat knitting machine as claimed in claim 1, characterised in that said first and second needles (8 1 F, 8 2 F; 8 1 B, 8 2 B) provided between each adjacent pair of sinkers (15) are inserted in a single common needle groove (7). A flat knitting machine as claimed in claim 1, 2, or 3, characterised in that said pair of needle beds (FB, BB) have said head portions opposed to each other, and said plurality of sinkers (15) are provided in spaced relationship from each other each by a distance corresponding to a predetermined gauge value, and at the top portions of said needle beds said first and second needles each having a transfer element are provided for sliding movement between said sinkers. A flat knitting machine as claimed in any one of claims 1 to 4, characterised in that said first and second needles are provided alternately between the sinkers (15), and the distance between said first and second needles (8 1 F, 8 2 F; 8 1 B, 8 2 B) are equal to each other. A flat knitting machine as claimed in any one of claims 1 to 4, characterised in that said first needles (8 1 F, 8 1 B) and said second needles (8 2 F,8 2 B) are individually provided parallel to each other at an equally spaced relationship from each other, and the distance between the first and second needles positioned between each adjacent pair of said sinkers (15) is different from the distance between one of the first and second needles and a needle positioned on the opposite side of one of said sinkers. A flat knitting machine as claimed in claim 4, characterised in that the ratio of the distance between the needle grooves of the first and second needles positioned between each adjacent pair of said sinkers and the distance between one of the needle grooves of the first and second needles and a groove for a needle positioned on the opposite side of one of the said sinkers ranges from 1:1 to 1:2.8. A flat knitting machine as claimed in any one of claims 1 to 7, characterised in that each of said transfer elements is a blade (13a) provided on a side portion of a body of each of said needles (8a). A flat knitting machine as claimed in claim 8, characterised in that the blades (13a) as the transfer elements are provided on the same sides of the bodies of said first and second needles. A flat knitting machine as claimed in claim 8, characterised in that the blades (13a) as the transfer elements are provided on different sides of the bodies of said first and second needles. A flat knitting machine as claimed in any one of claims 1 to 10, characterised in that a knitted fabric is formed by using one needle out of every two needles provided in the needle bed, said first and second needles have hooks of equal size, and means are provided to maintain the size of the sinker loops of the knitted fabric substantially equal to or not substantially larger than the size of needle loops of the knitted fabric.

Inventors: SHIMA MASAHIRO, SONOMURA MINORU, SHIMA, MASAHIRO, SONOMURA, MINORU
Applicants: SHIMA SEIKI MFG, SHIMA SEIKI MFG., LTD.
Application year: 1995
Main classification: D04B15
IPC codes: D04B15, D04B7, D04B1, D04B35