Circular knitting machine with jacquard pattern control mechanism

Abstract: A circular knitting machine and a jacquard pattern control mechanism therefor is provided in which knitting instrumentalities (27) slidably mounted in grooves in a rotating member, such as a needle cylinder, sinker cap or dial, are controlled by a rocker bar supporting member (40) slidably mounted in each groove behind the knitting instrumentality (27), the rocker bar supporting member (40) has at least one butt (41a) thereon and a rocker bar (44) pivotally mounted on the rocker bar supporting member and having magnetically attractable sections (44f, 44a) at opposite ends thereof. A magnetic attraction device (50) selectively attracts the magnetically attractable sections of the rocker bar to pivot the rocker bar to control the selection of knitting instrumentalities (27) to be moved from inactive to active positions, and a cam system (31, 32, 35, 46, 48) for moving the rocker bar supporting member (40) and selected knitting instrumentalities.

Description: Field of the Invention The present invention relates to circular knitting machines and more particularly to a jacquard pattern control mechanism for such circular knitting machines. Background of the Invention Circular knitting machines typically include a rotating needle cylinder having vertical grooves therein, in which cylinder needles are slidably mounted for movement between active (knitting) and inactive (welt) positions. In some machines, such needles are also movable to an intermediate (tuck) position. Single knit circular knitting machines normally include a sinker cap mounted on top of the needle cylinder for rotation with the needle cylinder. The sinker cap has radial grooves therein, equal in number and corresponding to the grooves in the needle cylinder. A sinker is slidably mounted in each groove in the sinker cap for radial movement between active (extended) and inactive (retracted) positions. To produce some knit fabrics, the sinkers are moved selectively to a plurality of different active or extended positions to bring different portions of the sinkers into cooperative relation with the needles, to form different stitch loops. Separate cam systems are provided for operating the needles and the sinkers to move the needles and sinkers between the inactive positions and the active positions or intermediate positions or combinations thereof. Typically, the needles and sinkers have operating butts thereon which coact with cam tracks to control and operate the needles and sinkers. In order to produce a variety of relatively intricate stitch patterns in the knit fabric, jacquard pattern control mechanisms are commonly provided and used. Such jacquard pattern control mechanisms typically select certain knitting needles for movement to the active (knitting) position while maintaining the other knitting needles in the inactive (welt) position. Most jacquard pattern control mechanisms rely on multiple jacks in the sinker cap grooves and intricate pattern selection control devices for selecting the particular jacks to operate the sinkers. One example of such a control mechanism is disclosed in Japanese patent Laid-Open No. 45755/91 (Publication No. 03045755A). Such control mechanisms operate rather slowly which limits the production speed of the circular knitting machine and the complexity of the control mechanism obstructs the visibility of the various components, making it difficult to monitor the operation of the sinkers or to feed the knitting yarns to the needles through the yarn guides, etc. Another example of a jacquard pattern control mechanism is disclosed in United States Patent No. 5,174,131. As is typical, the control mechanism is disclosed in patent No. 5,174,131 associated with knitting needles. Although this patent states that the control mechanism can be used to control the sinkers, no disclosure is provided as to the manner in which this control mechanism can be adapted to control the sinkers. Even in the control of the knitting needles, the control mechanism of patent No. 5,174,131 has several other disadvantages and deficiencies. For example, the rocker bar of the needle selection system is mounted directly on the knitting needle which has only one operating butt thereon. Additionally, the rocker bar is provided with a plurality of protruding butts for coaction with cam tracks to control the needle. If the butt of the knitting needle should become damaged, as frequently occurs, such as by knitting a yarn with a knot therein, the knitting needle will become uncontrollable, prompting the danger that one or more of the butts on the rocker bar may be broken. Further, the cam system associated with the rocker bar, as disclosed in patent No. 5,174,131, has a vertical cross section. Therefore, if an outside force acts on the rocker bar, the butt(s) thereon may disengage from the cam track(s). Jacquard pattern control mechanisms must include a pattern selection device for the needles and/or sinkers. Such pattern selection devices have taken many different forms, examples of which may be found in United States Patents Nos. 5,375,436; 5,241,288; 4,905,484; 3,518,845 and 3,283,541 and in Japanese Patent Laid-Open No. 299554/87. In U.S. Patents Nos. 5,375,436; 5,241,288 and 4,905,484 and Japanese Patent Laid-Open No. 299554/87, the pattern selection devices comprise an electromagnetic device combining a permanent magnet and an electromagnet. In each of these devices, the magnetic force of the permanent magnet is cancelled or demagnetized by the electromagnet to control the knitting needles. Therefore, the magnetic force of the electromagnet must be limited to the magnetic force of the permanent magnet. In order to obtain the necessary attraction for needle selection, both the permanent magnet and the electromagnet must be large. Because of space limitations, it is therefore difficult to install the requisite number of magnets to perform the needle selection function. U.S. Patents Nos 3 518 845 and 3 283 541 disclose an electromagnetic device including a plurality of electromagnets for performing the needle selection function. In these devices, two separate electromagnets are utilized, one for selecting the needles for movement to the active position and another for selecting the needles to remain in the inactive position. In practice, these electromagnetic devices are too large and very expensive. Our prior specification EP-A-0 752 490, which is relevant under Art 54(3) EPC, describes a circular knitting machine having a jacquard pattern control mechanism in which sinkers slidably mounted in sinker grooves in a sinker cap or dial are controlled by a rocker bar supporting member slidably mounted in each groove behind the sinker. The rocker bar supporting member has a butt thereon and a pivotally mounted rocker bar having magnetically attractable sections at opposite ends thereof. A magnetic attraction device selectively attracts the magnetically attractable sections of the rocker bar to pivot the rocker bar for controlling engagement thereof with a cam system and, hence, movement of the associated sinker from inactive to active positions. It is an object of the present invention to provide a jacquard pattern control mechanism for a circular knitting machine which is adapted to control the sinkers of the machine and which alleviates the aforementioned disadvantages and deficiencies of prior jacquard pattern control mechanisms. The invention consists in a circular knitting machine having knitting instrumentalities for forming knit fabric including a rotatable sinker cap having a plurality of grooves in which sinkers are slidably mounted, and control means for controlling said sinkers to produce a jacquard knit fabric, wherein said control means comprises a plurality of rocker bar supporting members each slidably mounted in the same groove as one of said sinkers, each of said rocker bar supporting members including at least one butt protruding therefrom, a plurality of elongate rocker bars having magnetically attractable opposite end portions each being pivotally mounted on one of said rocker bar supporting members for movement about a medial pivot, opposite end portions of said rocker bar being adapted to be selectively moved between operative and inoperative positions, magnetic attracting means operatively associated with said opposite end portions of said rocker bars for selectively attracting one of said magnetically attractable opposite end portions to pivot said rocker bars and selectively move one of said opposite end portions to said operative position and the other of said opposite end portions to said inoperative position, rocker bar operating cam means engageable with the end portion of said rocker bar in said operative position for either moving said rocker bar and said rocker bar supporting member from a retracted position to an extended position to engage and move said sinker or maintaining said rocker bar and said rocker bar supporting member in said retracted position, a sinker cam engageable with the butts of the sinkers for controlling said sinkers and for moving the same to at least one knitting position upon movement of said rocker bar supporting members to their extended positions and for maintaining said sinkers in a non-knitting position when said rocker bar supporting members are in their retracted positions, an intermediate member having at least one operating butt thereon slidably mounted in each of said grooves between the sinker and the rocker bar supporting member, and intermediate cam means for moving said intermediate members from a retracted position to an extended position, said intermediate cam means including upstream and downstream intermediate cams for successively forming low and high pile loops, which cams have top edges with upwardly inclined portions, said sinker cam having a bottom edge which includes a section extending from a point in vertical alignment with the top of the upwardly inclined portion of the top edge of the upstream intermediate cam to a point overlying the middle of the upwardly inclined portion of the top edge of the downstream intermediate cam, whereby said section prevents sinkers from advancing further than is necessary for low pile formation, and a section which extends from a point in vertical alignment with the middle of the upwardly inclined portion of the top edge of the downstream intermediate cam whereby to permit advancement of the sinkers by the downstream cam. Brief Description of the Drawings Figure 1 is a fragmentary, schematic view of a jacquard pattern control mechanism to which reference is made in order to explain the present invention; Figure 2 is an enlarged, fragmentary perspective view of the rocker bar supporting member, rocker bar, rocker bar cam and electromagnetic selection device of Figure 1; Figure 3 is a fragmentary elevational view of the rocker bar and the electromagnetic selection device shown in Figure 2; Figure 3A is a schematic view of the electromagnetic selection device and the wiring diagram therefor; Figure 4 is a fragmentary vertical selection view taken substantially along line 4-4 in Figure 1 ; Figure 5 is a fragmentary vertical sectional view taken substantially along line 5-5 in Figure 1; Figure 6A is a fragmentary sectional view taken substantially along line 6-6 in Figure 1 showing the sinker and jacquard pattern control mechanism in pile forming selection; Figure 6B is a view similar to Figure 6A showing the sinker and jacquard pattern control mechanism in non-pile selection; Figure 7A is a fragmentary sectional view taken substantially along line 7-7 in Figure 1 showing the pattern control mechanism in pile forming selection; Figure 7B is a view similar to Figure 7A showing the pattern control mechanism in non-pile selection; Figure 8A is a fragmentary sectional view taken substantially along line 8-8 in Figure 1 showing the pattern control mechanism in pile forming selection; Figure 8B is a view similar to Figure 8A showing the pattern control mechanism in non-pile selection; Figure 9 is a fragmentary sectional view taken substantially along line 9-9 in Figure 1; Figure. 10 is a reduced schematic view similar to Figure 1 illustrating a jacquard Pattern control mechanism for forming high and low pile in a knit fabric; Figure 12 is a perspective view illustrating a sinker for making high and low pile in a knit fabric; Figure 12 is a fragmentary sectional view similar to Figure 9 showing an intermediate retractable cam in retracted position; Figure 13 is an enlarged detail of the intermediate cam shown in Figure 12; Figure 14 is a schematic view similar to Figure 1 of a further embodiment showing a pattern control mechanism for controlling knitting needles; Figure 15 is a fragmentary vertical sectional view showing the mechanism shown in Figure 14; and Figure 16 is a schematic view similar to Figure 10 of an embodiment of the present invention for forming high and low pile in a knit fabric. Detailed Description of the Preferred Embodiments Referring now more specifically to the drawings and particularly to Figures 1-7, there is illustrated schematically and sectionally the core part of a circular knitting machine, generally indicated at 20 , which incorporates a jacquard pattern control mechanism. Circular knitting machine 20 includes a rotary needle cylinder 21 having a multiplicity of grooves (not shown in Figures 1-7) therein. A knitting needle 22 is mounted for vertical sliding movement in each of the grooves in the needle cylinder 21 . Circular knitting machine 20 further includes a cam block 23 mounted outside the needle cylinder 21 and mounts a needle cam 24 for raising and lowering the needles 22 between an active (knitting) position and an inactive (welting) position. A rotary sinker cap or dial 25 is mounted on top of the needle cylinder 21 and has a multiplicity of grooves 26 extending radially from the outer periphery to the inner periphery thereof. A sinker 27 is slidably mounted in each of the sinker grooves 26 for movement between an active (extended) position and an inactive (retracted) position. A sinker cam block 30 is mounted above the sinker cap 25 and mounts on its lower surface an inner sinker cam 31 and an outer sinker cam 32 in facing relation to the grooves 26 in sinker cap 25 . Sinker 27 has a main section 27a and an extension section 27b . The outer end of the main section 27a defines a vertical edge 27c . A butt 27d protrudes upwardly from extension section 27b and has vertical edges 27e and 27f. The main section 27a has a nose 27g defining a first top edge 27h for forming pile loops from a pile yarn PY . Main section 27a has a second top edge 27i for forming ground or non-pile stitch loops from a ground yarn GY . Pile yarn PY and ground yarn GY are fed to the needles 22 by a yarn carrier 28 (Figures 4-7). Cam 31 has a side edge 31a that engages the vertical edge 27c of sinker 27 and a side edge 31b which cooperates with a side edge 32a on cam 32 to define a cam track 33 which receives the butt 27d and controls sinker 27 by engagement of side edge 31b with vertical edge 27e and side edge 32a with vertical edge 27f . Cam 32 has another side edge 32b , the function of which will be described presently. An intermediate member 34 is disposed in each sinker groove in sinker cap 25 outwardly of sinker 27 (Figure 4). Intermediate member 34 has a butt 34a thereon which has a first vertical edge 34b and a second vertical edge 34c (Figure 1). A first intermediate cam 35 is mounted on cam block 30 adjacent cam 32 and has a first side edge 35a which cooperates with side edge 32b to define a cam track 36 . Cam track 36 receives butt 34a on intermediate member 34 and controls and moves intermediate member 34 by engagement of side edge 32b with vertical edge 34b and side edge 35a with vertical edge 34c (Figure 1). A second intermediate cam 37 is disposed in cam track 36 and has a first side edge 37a and a second side edge 37b . Side edge 37a has a first sloped or angled section 37a 1 , and a second straight section 37a 2 . Side edge 37b of cam 37 is straight and parallel to side edge 35a of cam 35 . Cam 37 divides cam track 36 into two branches 36a and 36b . If butt 34a on intermediate member 34 is caused to follow branch 36a of cam track 36 , side edge 37a of cam 37 engages vertical edge 34c of butt 34a and moves intermediate member 34 into contact with sinker 27 and moves sinker 27 further toward the needles 22 . Such movement brings the nose 27g of sinker 27 into operative position to form pile loops over top edge 27h . Thereafter, side edge 32b returns intermediate member 34 back to its retracted position which corresponds to branch 36b of cam track 36 . The second intermediate cam 37 is preferably mounted on cam block 30 for movement between an extended, operative position and a retracted, inoperative position (Figures 12 and 13). Accordingly, cam block 30 is provided with a recess 30a into which an inner end 38a of a threaded operating member 38 extends. Cam 37 is mounted on the inner end 38a of operating member 38 by receiving this inner end 38a in a cavity 37c in cam 37 . Cavity 37c is larger than the inner end 38a of operating member 38 such that cam 37 may move a predetermined amount longitudinally or axially of operating member 38 . A coil spring 39 is positioned around operating member 38 between cam 37 and the bottom of recess 30a to bias cam 37 toward the inner end of operating member 38 and toward its operative position. Thus, cam 37 protects the butt 34a from damage from outside forces which may act thereon. A rocker bar supporting member 40 (Figure 2) is slidably mounted in each sinker groove 26 outwardly of intermediate member 34 . Rocker bar supporting member 40 includes an inner end section 41 , the lower portion of which is received in sinker groove 26 and the upper portion of which includes a butt 41a . Butt 41a includes a first vertical edge 41b and a second vertical edge 41c. Rocker bar supporting member 40 includes a medial section 42 having a central portion 42a and opposite end portions 42b and 42c . The lower portion of central portion 42a is received in sinker groove 26 and the upper portion of which has a recess or socket 42d therein. Opposite end portions 42b and 42c of medial section 42 are of less height than central portion 42a such that the top edges thereof are recessed below the top edge of the central portion 42a . Finally, rocker bar supporting member 40 includes an outer end section 43 , the lower portion of which is received in sinker groove 26 . A rocker bar 44 is mounted on the medial section 42 of rocker bar supporting member 40 for pivotal movement by a circular pivot protrusion 44a which is received in socket 42d . Rocker bar 44 has symmetrical opposite end portions 44b and 44c which are beveled, wedge-shaped at their outer extremities at 44d and 44e . The lower portions of opposite end portions 44b and 44c are bulbous-shaped and serve to engage the upper edges of end portions 42b and 42c of medial section 42 of rocker bar supporting member 40 to limit the pivotal movement of rocker bar 44 . The upper sections 44f and 44g of end portions 42b and 42c are magnetically attractable and are raised above the central portion of rocker bar 40 . A rocker bar supporting member cam 46 is carried by cam block 30 adjacent cam 35 . Cam 46 has a side edge 46a which is straight and spaced from a second side edge 35b of cam 35 to define therewith a cam track 47 which receives and controls butt 41a on rocker bar supporting member 40 . Cam 35 has a concave section 35c in its second side edge 35b corresponding to the location of second intermediate cam 37 . Cam 46 has a second side edge 46b which is positioned to engage wedge-shaped end 44d of rocker bar 44 when rocker bar 44 is pivoted to have end portion 44b extended to maintain the rocker bar 44 and rocker bar supporting member 40 in the inactive, retracted position. A rocker bar actuating cam 48 is mounted on cam block 30 and has a side edge 48a spaced from side edge 46b a distance equal to the length of rocker bar 44 . Side edge 48a engages the wedge-shaped end 44e when rocker bar 44 is pivoted to position end portion 44c in extended position. Cam 48 has a protruding portion 48b in side edge 48a in alignment with and of the same shape as the concave section in side edge 35b of cam 35 . The protruding portion 48b preferably has a trapezoidal-shaped cross section corresponding to the wedge-shape of the end 44e of rocker bar 44 . Upstream of protruding portion 48b of cam 48 , a cancelling cam 49 is positioned above the path of travel of rocker bar 44 and includes an upwardly and outwardly sloped surface 49a to engage a pivoted or tilted rocker bar 44 and cam rocker bar 44 back to a level or neutral position. Cancelling cam 49 will function irrespective of the direction in which rocker bar 44 is pivoted. A magnetic attraction selection device, generally indicated at 50 , is positioned immediately downstream of cancelling cam 49 and above the path of travel of rocker bar 44 such that the rocker bar 44 on the rocker bar supporting member 40 passes closely therebeneath. Selection device 50 is positioned upstream of protruding portion 48b of cam 48 . Selection device 50 includes two magnetic attraction means (Figures 2 and 3) disposed in position to attract magnetically the magnetic attractable sections 44f and 44g , respectively, of rocker bar 44 when rocker bar 44 passes therebeneath. Preferably, magnetic attraction selection device 50 comprises a permanent magnet 53 in the center and first and second electromagnets 54 and 55 on opposite sides thereof, which define the magnetic attraction means. Permanent magnet 53 and electromagnets 54 and 55 are all supported by a support member 56 . Preferably, the outer tip of permanent magnet 53 has a mushroom-shaped cross section for reasons to be described presently. Electromagnets 54 and 55 include first and second exciting coils 54a , 55a on opposite sides of permanent magnet 53 and first and second cores 54b , 55b inside and extending to the left and right, respectively, of the coils 54a , 55a . The outer tips 54c , 55c of the cores 54b , 55b are slanted upwardly and outwardly from the inside to the outside to accommodate sufficient pivotal movement of rocker bar 44 without contact with these tips 54c , 55c . Also preferably, the magnetically attractable sections 44f and 44g of rocker bar 44 slant downwardly and outwardly for this same reason. The coils 54a , 55a are connected in series (Figures 3 and 3A). By applying positive or negative voltage to the electromagnets 54 , 55 , the tips 54c , 55c selectively attract magnetically attractable sections 44f , 44g of rocker bar 44 . For example, when positive voltage is applied from A to B (Figure 3A ), the first magnetic field 53b of the permanent magnet 53 is cut-off or cancelled by the magnetic flux generated by the first electromagnet 54 . At the same time, the magnetic flux generated by the second electromagnet 55 and the cut-off or cancelled first magnetic field of permanent magnet 53 enhance the second magnetic field 53c of the permanent magnet 53, thereby resulting in a stronger magnetic field. This stronger magnetic field causes the tip 55c of the core 55b to attract magnetically the magnetically attractable section 44g of rocker bar 44 . Such attraction pivots rocker bar 44 to move wedge-shaped end 44e into contact with side edge 48a of cam 48 . When a negative voltage is applied from A to B , the opposite electromagnetic reaction occurs, in that the second magnetic field 53c of permanent magnet 53 is cut-off or cancelled by the magnetic flux of electromagnet 55 and the first magnetic field 53b of permanent magnet is enhanced by the magnetic flux of electromagnet 54 and by the cut-off second magnetic field 53c of permanent magnet 53 . Such magnetic field causes the first electromagnet 54 to attract the magnetically attractable section 44f of rocker bar 44 to move wedge-shaped end 44d into engagement with side edge 46b of cam 46 . Referring now to Figures 10 and 11, there is illustrated another jacquard Pattern control mechanism in which like elements are referred to by like reference characters with the prime notation added. In with this mechanism, sinker 27' has a first nose 27g' defining a first top edge 27h' for forming high pile loops. Sinker 27' also has a second nose 127g between the first nose 27g' and the second top edge 27i' and defining a third or intermediate top edge 127h for forming low pile loops. Sinker cam 31' has a top edge 31a' and a bottom edge 31b' . Intermediate cam 32' has a top edge 32a' and a bottom edge 32b' . A second intermediate cam 37' is provided between side edges 32b' and 35a' of cam 35' in cam track 36' to divide cam track 36' into a first branch 36a' and a second branch 36b' for forming high pile loops. A third intermediate cam 137 is mounted in cam track 36' downstream of second intermediate cam 37' for forming low pile loops. Third intermediate cam 137 has a first side edge 137a and a second side edge 137b which are spaced apart a lesser distance than the side edges 37a' and 37b' of second intermediate cam 37' . Rocker bar actuating cam 48' has a first protrusion 48b' in alignment with second intermediate cam 37' and a second protrusion 148b downstream thereof in alignment with third intermediate cam 137 . Similarly, cam 35' has a first concave section 35c' and a second concave section 135c . A first magnetic selection device 50' is provided upstream of protrusion 48b' for attracting selectively the magnetically attractable sections 44f' and 44g' of rocker bar 44' . A second magnetic selection device 150 is mounted between protrusions 48b' and 148b . Second magnetic selection device 150 is of the same construction as first magnetic selection device 50' and therefore will not be described again. Cancelling cams 49' and 149 are provided upstream of the first and second magnetic selection devices 50' and 150 , respectively. Referring now to Figures 14 and 15 , there is illustrated a further embodiment of jacquard Pattern control mechanism in which like elements are referred to by like reference characters with the double prime notation added. A circular knitting machine 20" is illustrated with a needle cylinder 21" having a multitude of grooves 221a in the periphery thereof. A knitting needle 22" is slidably mounted in each groove 221a and coacts with a sinker 27" to form stitch loops which combine to form a knit fabric, as described herein a jacquard pile fabric. Needle 22" has a shank 222a with a butt 222b protruding therefrom. A pair of needle operating cams 71 and 72 mounted on a cam holder 70 define a cam track 73 which moves needle 22" up and down in the conventional manner. An intermediate jack member 234 is slidably mounted in groove 221a in cylinder 21" beneath needle 22" . Intermediate jack member 234 has an upper butt 234a adjacent the upper end thereof and a lower butt 234b at a medial portion thereof beneath the upper butt 234a . Intermediate member 234 includes an extension or tail 234c beneath the lower butt 234b . A first intermediate cam 74 defines a cam track 75 which receives upper butt 234a on intermediate jack member 234 . A second intermediate cam 76 defines a first cam track 77 and a second cam track 78 . Cam track 77 receives the lower butt 234b when needle 22" is selected for movement upwardly to the knitting position and cam track 78 receives the lower butt 234b when needle 22" is to be maintained in the welt position. A rocker bar supporting member 240 is mounted for sliding movement in groove 221a of cylinder 21'' for lateral movement to control the action of intermediate jack member 234 . Rocker bar supporting member includes a bifurcated upper end portion 241 which has opposed legs 241a , 241b which receive the extension or tail 234c of intermediate jack member 234 therebetween. Upper end portion 241 has a first butt 241c thereon and a second butt 241d spaced beneath the first butt 241c. A first rocker bar supporting member operating cam 80 defines a cam track 81 which receives butt 241c for controlling the upper portion of rocker bar supporting member 240 . A second cam 82 defines a cam track 83 which receives and controls butt 241d . A medial section 242 of rocker bar supporting member 240 includes a socket 242d for pivotally mounting a rocker bar 44" . Rocker bar 44'' has a circular protrusion mounted in socket 242d and has magnetically attractable section 44f'' and 44g" . Rocker bar 44" also has wedge-shaped ends 44d" and 44e" . A rocker bar actuating cam 80 defines a cam track 81 for receiving and controlling rocker bar 44" . A cancelling cam 49" is disposed adjacent the entrance to cam track 81 to engage and position rocker bar 44" level or in neutral position. A first magnetic selection device 50" is mounted upstream of cam track 81 and immediately downstream of cancelling cam 49" and beside the path of travel of rocker bar 44" . First magnetic selection device 50" includes magnetic attraction means for attracting selectively the magnetically attractable sections 44f'' and 44g'' of rocker bar 44" . A second magnetic device 250 may be placed downstream from first magnetic selection device 50'' should it be desired to further control needle 22" , such as to move the same to a tucking position. Of course, second magnetic selection device 250 is preceded by a second cancelling cam 249 , and should be followed by a second cam 82 . Referring now to Figure 16, there is illustrated an embodiment of the present invention in which like elements are referred to by similar reference characters in which the last two digits are the same as previous reference characters in Figure 10 preceded by the prefixes "3" or "4". In accordance with this embodiment, sinker 327 has a first nose 327g defining a first top edge 327h . Sinker 327 has a second nose 427 between the first nose 327g and the second top edge 327i and defining a third or intermediate top edge 427j for forming low pile loops. Sinker cam 331 has a top edge 331a and a bottom edge 331b . First intermediate cam 332 has a top edge 332a and a bottom edge 332b. A second intermediate cam 337 is provided between bottom edge 331b of cam 331 and a top edge 335a of cam 335 in cam track 336 to divide cam track 336 into a first branch 336a for forming low pile loops and a second branch 336b for forming no pile loops. A third intermediate cam 437 is mounted in cam track 336 downstream of second intermediate cam 337 and has a first edge 437a for forming high pile loops and a second edge 437b for forming no pile loops. Third intermediate cam 437 divides cam track 336 into a third branch 336c and a continuation of second branch 336b . The bottom edge 331b of sinker cam 331 has a second 331b' which extends from a point in vertical alignment with the top of the upwardly inclined portion of top edge 337a of second intermediate cam 337 to a point overlying the middle of the upwardly inclined portion of top edge 437a of third intermediate cam 437 . This section 331b' engages the forward edge 327e of sinker butt 327d to control positively the sinker 327 to prevent sinker 327 from advancing further than is necessary for low pile formation until the same is forcibly advanced by third intermediate cam 437 . Bottom edge 331b has a section 331b'' which permits such forcible advancement of sinker 327 by third intermediate cam 437 . Similarly, the bottom edge 332b of first intermediate cam 332 inclines downwardly immediately downstream of second intermediate cam 337 as indicated at 332b' and then upwardly at third intermediate cam 437 as indicated at 332b" . The bottom edge 332b engages the forward edge 334b of butt 334a on intermediate jack member 334 to control positively any advancing movement of the intermediate jack member 334 due to engagement of the rear edge 334c of butt 334a with second intermediate cam 337 or third intermediate cam 437 . Cam 335 has a bottom edge 335b which has a first concave section 335c therein in alignment with second intermediate cam 337 and a second concave section 435c in alignment with third intermediate cam 437 . These concave sections 335c and 435c permit advancement of rocker bar supporting member 341 and then positively retracts rocker bar supporting member 341 by engaging butt 341a thereof. Cam 348 has a first protrusion 348b in alignment with second intermediate cam 337 and a second protrusion 448b in alignment with third intermediate cam 437 . A first magnetic selection device 350 is provided upstream of protrusion 348b for attracting selectively sections 344f and 344g of rocker bar 344 . A second magnetic selection device 450 is mounted between protrusions 348b and 448b for attracting selectively sections 344f and 344g of rocker bar 344 . Cancelling cams 349 and 449 are provided upstream of the first and second magnetic selection devices 350 and 450 , respectively. The operation of the various jacquard Pattern control mechanism will now be described. When sinker 27 is to be advanced, a signal from a controller (not shown) is sent to the magnetic selection device 50 to cause electromagnet 55 to attract magnetically attractable section 44g of rocker bar 44 (Figure 3) to pivot rocker bar 44 and move wedge-shaped end 44e into extended position. By this time, ground yarn GY is supplied from yarn carrier 28 and crosses over top edge 27i of sinker 27 and is fed to the knitting needle 22 . As rocker bar 44 moves with rotating sinker cap 25 , wedge-shaped end 44e engages the protrusion 48b of cam 48 and rocker bar 44 and rocker bar supporting member 40 are pushed inwardly toward the cylinder 21 . Rocker bar supporting member 40 engages and pushes inwardly intermediate member 34 such that butt 34a engages the inwardly slanting section 37a 1 of side edge 37a of second intermediate cam 37 which pushes intermediate member 34 even further inwardly toward cylinder 21 . Intermediate member 34 engages sinker 27 and advances sinker 27 to its most extended inward position in which nose 27g is in position to receive pile yarn PY from yarn carrier 28 across the top edge 27h thereof to form a pile loop in concert with needle 22 (Figures 8A and 9). When butt 34a reaches the straight section 37a 2 of side edge 37a of second intermediate cam 37 , the tip of nose 27g of sinker 27 is preferably at least 0.3 mm inward from the circumferential action line L 1 (Figure 1) of the knitting needle 22 . Therefore, formation of a pile loop at least 0.3 mm from the tip of nose 27g is ensured and will prevent such pile loop from prematurely slipping off of top edge 27h of sinker 27 . While intermediate member 34 is being pushed further out by second intermediate cam 37 , butt 41a on rocker bar supporting member 40 engages the outwardly slanting portion of concave section 35c of first intermediate cam 35 which returns rocker bar supporting member 40 and thus rocker bar 44 to their original retracted positions. Of course, it is possible to omit intermediate member 34 and have rocker bar supporting member 40 act directly on sinker 27 . Suitable modification of the cam system would be required. When sinker 27 is not to be advanced, a signal is sent to electromagnet 54 so as to attract magnetically attractable section 44f of rocker bar 44 to pivot rocker bar 44 to extend wedge-shaped end 44d . Rocker bar 44 does not engage rocker bar actuating cam 48 and therefore rocker bar 44 and rocker bar supporting member 40 do not move inwardly in groove 26 of sinker cap 25. Consequently, intermediate member 34 is not pushed inwardly and butt 34a thereon remains in branch 36b of cam track 36. Sinker 27 is thus only controlled by cam track 33 and both the pile yarn PY and ground yarn GY are fed to needle 22 and form ground stitch loops across second top edge 27i of sinker 27 . The action line L 2 (Figure 1) shows the action of sinker 27 forming pile and non-pile loops in the knitted fabric. In the foregoing manner, the circular knitting machine 20 forms a figured jacquard pile fabric having pile and non-pile areas based on the pattern signal output by the controller (not shown). For convenience, the action line L 1 of needle 22 shows movement of needle 22 only between the welting and knitting positions. However, it is contemplated that needle 22 may be moved between three positions -- knitting, tucking and welting -- by a known needle selection device. Also, the cams 31 , 32, 35 , 46 and 48 are illustrated as units formed in a straight line. It is contemplated, however, that such cams may be formed by multiple cam segments if it is more convenient. In the sinker mechanism illustrated in Figures 10 and 11, the sinker 27' has three operative positions. The first of these positions is the high pile forming position; the second position is the low pile forming position; and the third position is the ground loop or non-pile forming position. To move sinker 27' to the first position, a signal is sent to electromagnet 55' to attract magnetically attractable section 44g' of rocker bar 44' to pivot rocker bar 44' . Wedge-shaped end 44e' engages the first protrusion 48b' of cam 48' and moves the rocker bar 44' and rocker bar supporting member 40' inwardly. Rocker bar supporting member 40' moves intermediate member 34' inwardly to cause butt 34a' thereon to engage second intermediate cam 37' and move sinker 27' to its innermost position. Pile yarn PY will be fed to needle 22' across top edge 27h' of nose 27g' to form a high pile loop. Meanwhile, butt 41a' on rocker bar supporting member 40 engages the outwardly slanting portion of concave section 35c' of side edge 35b' of cam 35 to return rocker bar supporting member 40' to its original position. Rocker bar 44' passes under second cancelling cam 149 which returns rocker bar 44' to its neutral position. When low pile is to be formed, a signal is sent to second magnetic selection device 150 and particularly to electromagnet 155 to attract section 44g' of rocker bar 44' . Wedge-shaped end 44e' then engages second protrusion 148b of cam 48' to push rocker bar supporting member 40' inwardly to cause butt 34a' on intermediate member 34' to engage third intermediate cam 137 . Third intermediate cam 137 pushes sinker 27' to its second position such that second nose 127g receives pile yarn PY on second top edge 127g thereof to form low pile loops. When non-pile loops are to be formed, signals are sent to electromagnets 54' and 154 to attract section 44f' of rocker bar 44' . Rocker bar 44' thus passes protrusions 48b' and 148b and rocker bar supporting member 40' and intermediate member 34' are not pushed inwardly. Sinker 27' is thus controlled only by cams 31' and 32' and forms only ground or non-pile loops across top edge 27i' of sinker 27' . The embodiment of the member illustrated in Figure 16 operates virtually the same as the mechanism illustrated in Figures 10 and 11 except that sinker 327 is controlled positively at all times. Accordingly, the operation of this embodiment will not be described further. The jacquard pattern control mechanism of the present invention is not limited to making jacquard pile fabrics. Such control mechanism can be used to control selectively knitting instrumentalities, such as sinkers, cylinder needles, dial needles and jacks, etc. to at least two different paths. In the mechanism illustrated in Figures 14 and 15, needle 22" may be moved between at least two positions, i.e., welting and knitting positions. When needle 22'' is not to be raised, but is to be maintained in the welting position, a signal is sent to electromagnet 55" of magnetic selection device 50" to attract section 44g'' of rocker bar 44" . Wedge-shaped end 44e" of rocker bar 44" is moved to extended position and engages the upwardly inclined surface 80a , which has a trapezoidal cross section, of cam 80 to raise rocker bar supporting member 240 upwardly. Butt 241c of rocker bar supporting member 240 engages cancel cam 100 immediately below the bifurcated end 241 of rocker bar supporting member 240 and bifurcated end 241 is pushed outwardly by the slanting portion 1000a of cam 100 . Bifurcated end 241 pushes out extension 234c of intermediate member 234 . Butt 234b on intermediate member 234 does not enter cam track 77 of cam 76 but passes thereby and does not move upwardly. Accordingly, needle 22'' remains in the welting position. After rocker bar 44" passes the summit of cam 80 , butt 241d of rocker bar supporting member 240 engages a downward slanting section 110a of an intermediate cam 110 , thus returning rocker bar supporting member 240 to its original position. The extension 234c of intermediate member 234 returns to its original position and butt 234b enters cam track 78 on cam 76 . To raise knitting needle 22" , a signal is sent to electromagnet 54" so as to attract section 44f" of rocker bar 44'' . Rocker bar 44" thus passes beside section 80a of cam 80 and is not raised upwardly. Butt 241c does not engage cancelling cam 100 and extension 234c is not pushed outwardly. Therefore, butt 234b enters cam track 77 and intermediate member 234 is raised upwardly by cam 76 and knitting needle 22" is raised to the knitting position. If desired, needle 22" can be raised to a tucking position. In such event, second magnetic attraction device 250 is provided, as is second cam 82. According to the present invention, the bevelled wedge-shaped ends of the rocker bar 44 , 44' or 44" firmly engage the rocker bar operating cams 48 , 48' or 80 which have a trapezoidal-shaped cross section. Therefore, the rocker bar 44 , 44' or 44" does not come off of the cam 48 , 48' or 80 thereby ensuring control with no selection errors. Furthermore, the rocker bar 44 , 44' or 44" is free of protruding butts, thereby reducing the possibility of breakage of a butt even when there is a selection error. In addition, at the point where the sinker 27 or 27' changes direction, the vertical edges 27c and vertical edge 27e are held by the side edges of cam 31 . Accordingly, it is possible to run the circular knitting machine 21 with a jacquard pattern as a knitting machine producing a non-patterned fabric. Furthermore, the magnetic attraction devices 50 , 50' 150 , 50" and 250 can be small and fit into very limited spaces because only the rocker bar 44 , 44' or 44" is being controlled. Accordingly, the production of a wide variety of jacquard patterns under computer control can now be accomplished. Whilst reference is made in the description and claims to the various cams having top and bottom edges etc, it will be appreciated that, in an actual circular knitting machine, such edges may not be physically disposed in these relative positions. This terminology is used merely to facilitate the description of the control mechanism in conjunction with the schematic plan views thereof illustrated in the drawings and is not intended to restrict the cams to being one above another. Hence, in the case of sinkers, the so called top and bottom edges of the cams will, be radially disposed inner and outer edges.

Claims: A circular knitting machine having knitting instrumentalities (22,27) for forming knit fabric including a rotatable sinker cap (25) having a plurality of grooves in which sinkers (327) are slidably mounted, and control means for controlling said sinkers to produce a jacquard knit fabric, wherein said control means comprises a plurality of rocker bar supporting members (340) each slidably mounted in the same groove as one of said sinkers (327), each of said rocker bar supporting members including at least one butt (341a) protruding therefrom, a plurality of elongate rocker bars (344) having magnetically attractable opposite end portions (344f, 344g) each being pivotally mounted on one of said rocker bar supporting members for movement about a medial pivot, opposite end portions of said rocker bar being adapted to be selectively moved between operative and inoperative positions, magnetic attracting means (350, 450) operatively associated with said opposite end portions of said rocker bars for selectively attracting one of said magnetically attractable opposite end portions to pivot said rocker bars and selectively move one of said opposite end portions to said operative position and the other of said opposite end portions to said inoperative position, rocker bar operating cam means (346, 348) engageable with the end portion of said rocker bar in said operative position for either moving said rocker bar (344) and said rocker bar supporting member (340) from a retracted position to an extended position to engage and move said sinker (327) or maintaining said rocker bar and said rocker bar supporting member in said retracted position, a sinker cam (331) engageable with the butts (327d) of the sinkers for controlling said sinkers and for moving the same to at least one knitting position upon movement of said rocker bar supporting members (340) to their extended positions and for maintaining said sinkers in a non-knitting position when said rocker bar supporting members are in their retracted positions, an intermediate member (334) having at least one operating butt (334a) thereon slidably mounted in each of said grooves between the sinker (327) and the rocker bar supporting member (340), and intermediate cam means (332,337,437) for moving said intermediate members from a retracted position to an extended position, said intermediate cam means including upstream and downstream intermediate cams (337,437) for successively forming low and high pile loops, which cams have top edges (337a,447a) with upwardly inclined portions, said sinker cam having a bottom edge (331b) which includes a section (331b') extending from a point in vertical alignment with the top of the upwardly inclined portion of the top edge (337a) of the upstream intermediate cam (337) to a point overlying the middle of the upwardly inclined portion of the top edge (437a) of the downstream intermediate cam (437), whereby said section (331b') prevents sinkers (327) from advancing further than is necessary for low pile formation, and a section (331b") which extends from a point in vertical alignment with the middle of the upwardly inclined portion of the top edge (437a) of the downstream intermediate cam (437) whereby to permit advancement of the sinkers by the downstream cam. A circular knitting machine according to claim 1 wherein said intermediate cam means also positively moves said intermediate member (334) from the extended position to the retracted position. A circular knitting machine according to claim 2 wherein the intermediate cam means includes a further intermediate cam (332) which cam (332) which extends between the sinker cam and said upstream and downstream cam members and has a bottom edge inclined downwardly (332b') immediately downstream of the upstream intermediate cam (337) and then upwardly (332b") at said downstream cam (437) whereby positively to control movement of the intermediate members (334) due to engagement of the butts (334a) thereof with the upstream or downstream cam members. A circular knitting machine according to claim 1, 2 or 3 wherein said opposite end portions of each rocker bar (344) have a bevelled wedge shape and wherein said rocker bar operating cam means (346,348) has a trapezoidal-shaped cross section. A circular knitting machine according to claim 1, 2, 3 or 4 wherein each sinker (327) has a plurality of noses for forming ground knit stitch loops and pile stitch loops. A circular knitting machine according to claim 1, 2, 3 or 4 wherein each sinker (327) has a plurality of sinker noses (327a,427) for forming stitch loops of different sizes and wherein each rocker bar (344) has a plurality of magnetically attractable sections (344f,344g) at said opposite end portions for controlling said sinker to produce stitch loops of varying size. A circular knitting machine according to any preceding claim wherein said intermediate cam means is movable between an operative position in which said intermediate cam means is engageable by the butt 334a) on the intermediate members (334) to produce both pile and ground stitch loops and an inoperative position in which said intermediate cam means is not engageable with said butts on said intermediate members to produce only ground stitch loops. A circular knitting machine according to any preceding claim including an intermediate jack member (234) slidably mounted in each groove (221a) of said needle cylinder (21") between said needle (27") and a rocker bar supporting member (240) and having a pair of spaced apart butts (234a,234b) thereon, said intermediate jack member being rockable to move one of said butts thereon between an operative position and an inoperative position, and wherein said rocker bar supporting member is operatively associated with said intermediate jack member for selectively rocking said intermediate jack member between its operative and inoperative positions, and rocker bar operating cam means (80) includes means for selectively operating said rocker bar supporting member (240) to rock said intermediate jack member. A machine according to any preceding claim wherein the magnetic attracting means (350,450) comprises an elongate permanent magnet (53) and first and second electromagnets (54,55) connected to opposite ends of said permanent magnet in series. A machine according to claim 9 wherein said permanent magnet (53) has an outer tip adjacent the rocker bars (344) which has a mushroom-shaped cross section. A machine according to any preceding claim wherein said magnetically attractable sections of each rocker bar (344) slant downwardly and outwardly with respect to a medial portion of said rocker bar.

Inventors: HASHIHIRO SHINJI, SHIBATA TAKAO, YORISUE SHOZO, HASHIHIRO, SHINJI, SHIBATA, TAKAO, YORISUE, SHOZO
Applicants: PRECISION FUKUHARA WORKS LTD, PRECISION FUKUHARA WORKS, LTD
Application year: 1997
Main classification: D04B15
IPC codes: D04B15